Zebra GC420-200520-000 User Manual

11/23/199711/23/1997

Zebra® GC420d™

Desktop Thermal Printer

User Guide

ii

P1039494-001 GC420d™ User Guide 8/15/2011

©2011 ZIH Corp. GC420,GC420d, ZBI, ZBI 2.0, ZBI-Developer, Uni-Ribbon,
ZebraDesigner, ZebraNet, EPL, EPL2, ZPL, ZPL II, OpenACCESS and all product names
and numbers are Zebra trademarks, and Zebra, the Zebra head graphic, ZPL, ZPL II,
Element Energy Equalizer circuit, E3 Circuitand, and ZebraNet are registered trademarks
of ZIH Corp. All rights reserved. All other trademarks are the property of their respective
owners.

iii

This product may contain ZPL®, ZPL II®, and ZebraLink™ programs; Element Energy

3

Equalizer™ Circuit; E

®; and Monotype Imaging fonts. Software ©ZIH corp. All rights

reserved worldwide.

All rights reserved worldwide.Monotype®, Intellifont® and UFST® are trademarks of
Monotype Imaging, Inc. registered in the United States Patent and Trademark Office and
may be registered in certain jurisdictions.

CG Triumvirate is a trademark of Monotype Imaging, Inc. and may be registered in some
jurisdictions.

TrueType® is a trademark of Apple Computer, Inc. registered in the United States Patent
and Trademark Office and may be registered in certancertain jurisdictions.

Proprietary Statement

This manual contains proprietary information of Zebra Technologies Corporation and its
subsidiaries (“Zebra Technologies”). It is intended solely for the information and use of
parties operating and maintaining the equipment described herein. Such proprietary
information may not be used, reproduced, or disclosed to any other parties for any other
purpose without the express written permission of Zebra Technologies.

Product Improvements

Continuous improvement of products is a policy of Zebra Technologies. All specifications
and designs are subject to change without notice.

Liability Disclaimer

Zebra Technologies takes steps to ensure that its published Engineering specifications and
manuals are correct; however, errors do occur. Zebra Technologies reserves the right to
correct any such errors and disclaims liability resulting therefrom.

Limitation of Liability

In no event shall Zebra Technologies or anyone else involved in the creation, production,
or delivery of the accompanying product (including hardware and software) be liable for
any damages whatsoever (including, without limitation, consequential damages including
loss of business profits, business interruption, or loss of business information) arising out
of the use of, the results of use of, or inability to use such product, even if Zebra
Technologies has been advised of the possibility of such damages. Some jurisdictions do
not allow the exclusion or limitation of incidental or consequential damages, so the above
limitation or exclusion may not apply to you.

Canadian DOC Compliance Statement

This Class B digital apparatus complies with Canadian ICES-003.
Cet appareil numérique de la classe B est conforme à la norme NMB-003 du Canada.

8/15/2011 GC420d™ User Guide P1039494-001

iv

FCC Compliance Statement

This device complies with Part 15 rules. Operation is subject to the following two conditions:

1. This device may not cause harmful interference, and

2. This device must accept any interference received, including interference that may cause

undesired operation.

This equipment has been tested and found to comply with the limits for Class B Digital
Devices, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable
protection against harmful interference when the equipment is operated in a residential
environment. This equipment generates, uses, and can radiate radio frequency energy and, if
not installed and used in accordance with the product manuals, may cause harmful interference
to radio communications. However, there is no guarantee that interference will not occur in a
particular installation. If this equipment does cause harmful interference to radio or television
reception, the user is encouraged to do one or more of the following measures:

• Reorient or relocate the receiving antenna.

• Increase the separation between the equipment and receiver.

• Connect the equipment into an outlet on a circuit different from that to which the receiver
is connected.

• Consult the dealer or an experienced RF service technician for help.

The user is cautioned that any changes or modifications not expressly approved by Zebra
Technologies could void the user’s authority to operate the equipment. To ensure compliance,
this printer must be used with fully shielded communication cables.

Environmental Management

Do not dispose of this product in unsorted municipal waste. This product is recyclable, and
should be recycled according to your local standards.

For more information, please see our website at:

Web address: www.zebra.com/environment

P1039494-001 GC420d™ User Guide 8/15/2011

About This Document

This section provides you with contact information, document structure and organization, and
additional reference documents.

Contents

Who Should Use This Document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi

How This Document Is Organized . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi

Contacts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .vii

Document Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii

8/15/11 GC420d™ User Guide P1039494-001 Rev. 1

vi

Who Should Use This Document

Who Should Use This Document

This User Guide is intended for use by any person who needs to operate or to troubleshoot
problems with the printer.

How This Document Is Organized

The User Guide is set up as follows:

Section Description

Introduction on page 1 This section describes what you get in your

Getting Started on page 9 This section describes how to set up your printer

shipping box and provides an overview of printer
features. This section also has procedures that
describe how to open and close the printer and
report any problems.

for the first time and use the most common
operating procedures for loading media.

Print Operations on page 27 This section provides media and print handling,

font and language support, and the set up of less
common printer configurations.

Printer Options on page 41 This section covers the common printer options

and accessories with brief descriptions and how to
get you started using or configuring your printer
option or accessory.

Maintenance on page 55 This section provides routine cleaning and

maintenance procedures.

Troubleshooting on page 67 This section provides information about printer

error reporting that you might need for printer
troubleshooting. Assorted diagnostic tests are
included.

Appendix: Interface Wiring
on page 81

Appendix: Dimensions on page 87 This section provides external printer dimensions

Appendix: ZPL Configuration

on page 91

This section provides additional interface
information and wiring diagrams to assist with
printer to host system integration (typically a PC).

for the standard printer and printer with options.

This section briefly covers printer configuration
and includes a cross-reference to ZPL printer
configuration commands.

P1039494-001 Rev. 1 GC420d™ User Guide 8/15/11

Contacts

Contacts

vii

Technical Support via the Internet is available 24 hours per day, 365 days per year.

Web Site: www.zebra.com
E-mail Back Technical Library:

E-mail address: [e-mail]
Subject line: Emaillist

Self Service Knowledge Base: www.zebra.com/knowledgebase
Online Case Registration: www.zebra.com/techrequest

Which Department

Do You Need?

Regional Headquarters Zebra Technologies Corporation

475 Half Day Road, Suite 500
Lincolnshire, IL 60069 USA

T: [phone]
Toll-free [phone]
F: [phone]

Technical Support

For questions on the
operation of Zebra
equipment and software,
please call your distributor.
For additional assistance,
contact us.

Please have your model and
serial numbers available.

Repair Service
Department

For back-to-base service
and repair.

Technical Training
Department

For Zebra product training
courses.

Inquiry Department

For product literature and
distributor and dealer
information.

Customer Service
Department (US)

Internal Sales
Department (UK)

For printers, parts, media,
and ribbon, please call your
distributor or contact us.

Key:

T: Telephone
F: Facsimile
E: E-mail

T: +1 877 ASK ZEBRA (275 9327)
F: [phone]

Hardware: [e-mail]
Software: [e-mail]

Kiosk printers:

T: [phone]
E: [e-mail]

T: +1 877 ASK ZEBRA (275 9327)
F: [phone]

E: [e-mail]

To request a repair in the U.S.,
go to www.zebra.com/repair

T: [phone]
T: [phone]
F: [phone]

E: [e-mail]

T: +1 877 ASK ZEBRA (275 9327)

E: [e-mail]

T: +1 877 ASK ZEBRA (275 9327)

E: [e-mail]

The Americas

.

Europe, Middle East,

and Africa

Zebra Technologies Europe
Limited
Dukes Meadow
Millboard Road
Bourne End
Buckinghamshire, SL8 5XF
United Kingdom

T: [phone]
F: [phone]

T: [phone]
F: [phone]

E: [e-mail]

T: [phone]
F: [phone]

New requests: [e-mail]
Status updates:

[e-mail]

T: [phone]
F: [phone]

E: [e-mail]

T: [phone]
F: [phone]

E: [e-mail]

T: [phone]
F: [phone]

E: [e-mail]

Asia Pacific

and India

Zebra Technologies Asia Pacific
Pte. Ltd.
120 Robinson Road
#06-01 Parakou Building
Singapore 068913

T: + 65 6858 0722
F: [phone]

T: [phone]
F: [phone]

E: China: [e-mail]

All other areas:

[e-mail]

T: [phone]
F: [phone]

E: China: [e-mail]

All other areas:

[e-mail]

T: + 65 6858 0722
F: [phone]

E: China: [e-mail]

All other areas:

[e-mail]

E: China:

[e-mail]

All other areas:

APACChannelmarketing@zebra.c
om

T: [phone]
F: [phone]

E: China: [e-mail]

All other areas:

[e-mail]

8/15/11 GC420d™ User Guide P1039494-001 Rev. 1

viii

Document Conventions

Document Conventions

The following conventions are used throughout this document to convey certain information.

Alternate Color (online only) Cross-references contain hot links to other sections in this
guide. If you are viewing this guide online in .pdf format, you can click the cross-reference
(blue text) to jump directly to its location.

Command Line Examples Command line examples appear in Courier New font. For
example, type

Files and Directories File names and directories appear in Courier New font. For
example, the

Icons Used

Caution • Warns you of the potential for electrostatic discharge.

ZTools to get to the Post-Install scripts in the bin directory.

Zebra<version number>.tar file and the /root directory.

Caution • Warns you of a potential electric shock situation.

Caution • Warns you of a situation where excessive heat could cause a burn.

Caution • Advises you that failure to take or avoid a specific action could result in physical

harm to you.

Caution • (No icon) Advises you that failure to take or avoid a specific action could result in

physical harm to the hardware.

Important • Advises you of information that is essential to complete a task.

Note • Indicates neutral or positive information that emphasizes or supplements important

points of the main text.

Example • Provides an example, often a scenario, to better clarify a section of text.

P1039494-001 Rev. 1 GC420d™ User Guide 8/15/11

Contents

• About This Document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

Who Should Use This Document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi

How This Document Is Organized . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi

Contacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

Document Conventions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii

• Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

1 • Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

GC420d™ Thermal Printers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

What’s in the Box? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Unpack and Inspect the Printer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Your Printer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Printer Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Operator Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2 • Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Attaching Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Loading Roll Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Preparing Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Placing the Roll in the Media Compartment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Printing a Test (Printer Configuration) Label . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Pre-install Windows® Printer Drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Connecting your Printer to a Computer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Interface Cable Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

After Your Printer is Connected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

3 • Print Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Determining Printer Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

8/15/2011 GC420d™ User Guide P1039494-001

x

Long Term Printer In-activity or Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Thermal Printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Modes of Printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Print Media Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Determining Thermal Media Types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Replacing Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Adjusting the Print Width. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Adjusting the Print Quality. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Media Sensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Printing on Fan-Fold Media. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Printing with Externally Mounted Roll Media. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Fonts and Your Printer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Localizing the Printer with Code Pages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Identifying Fonts in Your Printer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Stand Alone Printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Sending Files to the Printer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Print Meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

EPL Line Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

4 • Printer Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Label Dispenser Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Cutter Option. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Loading Media with the Cutter Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

ZebraNet® 10/100 Internal (Wired) Print Server Option . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Printer Network Configuration Status Label . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Zebra® KDU — Printer Accessory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

KDU Plus™ — Printer Accessory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

ZBI 2.0™ — Zebra Basic Interpreter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

5 • Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Cleaning the Printhead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Media Path Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Platen Cleaning and Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Other Printer Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Replacing the Printhead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

6 • Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Status Light Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Status Light Error Resolutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Print Quality Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Manual Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

P1039494-001 GC420d™ User Guide 8/15/2011

Troubleshooting Tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Printing a Configuration Label . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Recalibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Resetting the Factory Default Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Communications Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Feed Button Modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

A • Appendix: Interface Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Universal Serial Bus (USB) Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Parallel Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Ethernet Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Serial Port Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

B • Appendix: Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

External GK Printer Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

C • Appendix: ZPL Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Managing Printer Configuration with ZPL Programming. . . . . . . . . . . . . . . . . . . . . . . . . . 92

ZPL Configuration Status to Command Cross-reference . . . . . . . . . . . . . . . . . . . . . . . . . 93

Printer Memory Management and Related Status Reports . . . . . . . . . . . . . . . . . . . . . . . 96

ZPL Programming for Memory Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

xi

8/15/2011 GC420d™ User Guide P1039494-001

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Notes • ___________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

P1039494-001 GC420d™ User Guide 8/15/2011

1

Introduction

This section describes what you get in your shipping box and provides an overview of printer
features. This includes procedures that describe how to open and close the printer and report
any problems.

Contents

GC420d™ Thermal Printers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

What’s in the Box? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Unpack and Inspect the Printer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Your Printer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Printer Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Operator Controls. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

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2

GC420d™ Thermal Printers

GC420d™ Thermal Printers

The Zebra® GC420d™ model is the best value in a desktop thermal printer. The GC420d™
printer provides direct thermal printing at speeds up to 4 ips (inches per second) at a 203 dpi
(dots per inch) print density. The GGC420d™ supports both ZPL™ and EPL™ Zebra printer
programming languages and a wide variety of interface and feature options.

The GC420 printers feature:

• Automatic printer language detection and switching between ZPL and EPL
programming and label formats.

• OpenAccess™ design for simplified media loading.

• Color-coded operator controls and media guides.

• Zebra™ Global Printing Solution – supports Microsoft Windows keyboard encoding
(and ANSI), Unicode UTF-8 and UTF 16 (Unicode Transformation Formats), XML,
ASCII (7 and 8 bit used by legacy programs and systems), basic single and double
byte font encoding, Hexadecimal encoding, and custom character maps (DAT table
creation, font linking, and character remapping).

• Improved printer performance: faster print speeds and a 32-bit processor.

• A complete suite of free software applications and drivers to configure printer
settings, design and print labels and receipts, get printer status, import graphics and
fonts, send programming commands, update firmware, and download files. Clone
printer settings and send graphics, files, fonts, and firmware (updates) to one or more
Zebra® Ethernet and locally connected printers with ZebraNet™ Bridge.

• Maintenance reporting enabled and customizable by the user.

• The GC420 direct thermal printer models also include support for Line Mode printing
to support EPL1 legacy programming based printing applications.

The GC420 printers offer these basic printer options:

• Label Dispense (Peel-Off).

• General Media Cutter

• Internal 10/100 Print Server and Ethernet Interface.

• Zebra® ZBI 2.0™ (Zebra BASIC Interpreter) programming language. ZBI™ allows
you to create custom printer operations that can automate processes, use peripherals
(i.e. scanners, scales, keyboards, Zebra® KDU or KDU Plus™, etc.) all without being
attached to a PC or network.

This user’s guide provides all the information you need to operate your printer on a daily basis.
To create label formats, refer to your programming guides or label design applications such as
ZebraDesigner™.

Your printer, when connected to a host computer, functions as a complete system for printing
labels and tags.

Note • Many printer settings may also be controlled by your printer’s driver or label design

software. Refer to the driver or software documentation for more information.

P1039494-001 GC420d™ User Guide 8/15/2011

What’s in the Box?

Power Cord

varies by locale or region

Documentation

and Software

Power

Supply

Cleaning Pen

Printer

Save the carton and all packing materials in case you need to ship or store the printer later.
After unpacking, make sure you have all parts. Follow the procedures for inspecting the
printer to familiarize yourself with printer parts so you can follow the instructions in this book.

What’s in the Box?

3

8/15/2011 GC420d™ User Guide P1039494-001

Unpack and Inspect the Printer

When you receive the printer, immediately unpack it and inspect for shipping damage.

• Save all packing materials.

• Check all exterior surfaces for damage.

• Open the printer and inspect the media compartment for damage to components.

If you discover shipping damage upon inspection:

• Immediately notify the shipping company and file a damage report. Zebra
Technologies Corporation is not responsible for any damage to the printer incurred
during shipment, and will not cover the repair of this damage under its warranty
policy.

• Keep all packaging material for shipping company inspection.

• Notify your authorized Zebra

®

reseller.

4

Interface

Connectors

Feed

Button

Status

Light

Release
Latches

Release
Latches

DC Power

Receptacle

Power

Switch

Fan-Fold Media Entry Slot

What’s in the Box?

Your Printer

Opening the printer

To access the media compartment, you must open the printer. Pull the release latches towards
you and lift the cover. Check the media compartment for loose or damaged components.

Caution • The discharge of electrostatic energy that accumulates on the surface of the

human body or other surfaces can damage or destroy the printhead or electronic
components used in this device. You must observe static-safe procedures when working
with the printhead or the electronic components under the top cover.

P1039494-001 GC420d™ User Guide 8/15/2011

Printer Features

Label-Taken

Sensor

Peel Bar

Platen

Roller

Dispenser Option

BlackLine

Sensor

Gap

Sensor

Roll Holder and

Media Guides

Head-Up Sensor

(inside)

Pinch Roller

Dispenser Door

(open)

Printhead

Media

Guides

Media Guide

Adjustment

What’s in the Box?

5

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6

Power OFF Power ON

Power Switch

Power Switch

What’s in the Box?

Operator Controls

Power Switch

Press up to turn ON or down to turn OFF the printer.

Caution • The printer power should be turned off before connecting or disconnecting the

communications and power cables.

Feed Button

• Tap the Feed button once to force the printer to feed one blank label.

• Press the Feed button to take the printer out of a “pause” condition. The printer is put into
“pause” by either a programming command or an error condition. See What the Status

Light is Telling You on page 68 in the Troubleshooting chapter.

• Use the Feed button for printer setup and status (see Feed Button Modes on page 78 in the
Troubleshooting chapter).

P1039494-001 GC420d™ User Guide 8/15/2011

Status Light

Feed

Button

Status

Light

Located on the top case next to the feed button, the status light functions as a printer
operational indicator (see Status Light Descriptions on page 68).

What’s in the Box?

7

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8

What’s in the Box?

Closing the printer

1. Lower the top cover.

2. Press down until the cover snaps closed.

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2

Getting Started

This section describes how to set up your printer for the first time and use the most common
operating procedures for loading media.

Contents

Attaching Power. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Loading Roll Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Printing a Test (Printer Configuration) Label . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Pre-install Windows® Printer Drivers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Connecting your Printer to a Computer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

After Your Printer is Connected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

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10

Power
Connector

Power

Switch

Plug Varies
by Country

Active Power

Light

Power

Receptacle

AC
Power
Cord

Printer

Power
Supply

IEC 60320-C

Attaching Power

Attaching Power

Important • Set up your printer so that you can handle the power cord easily if needed. To

make certain the printer cannot carry electrical current, you must separate the power cord
from the power supply receptacle or AC electrical outlet.

Caution • Never operate the printer and power supply in an area where they can get wet.

Serious personal injury could result!

1. Make sure the printer’s power switch is in the off position (down).

2. Insert the AC power cord into the power supply.

3. Plug the other end of the cord into an appropriate AC electrical outlet. Note: The active

power light will go on if power is on at the AC outlet.

4. Insert the power supply’s power connector into the printer’s power receptacle.

P1039494-001 GC420d™ User Guide 8/15/2011

Note • Ensure the appropriate power cord with a three (3) prong plug and an
IEC 60320-C5 connector are used at all times. These power cords must bear the
relevant certification mark of the country in which the product is being used.

Loading Roll Media

When you load media, you must place the roll onto the media hangers.

You must use the correct media for the type of printing you require.

Preparing Media

Whether your roll media is inside or outside wound, you load it into the printer the same way.

• Remove the outside length of media. During shipment, handling, or storage, the roll may
become dirty or dusty. Removing the outside length of media avoids dragging adhesive or
dirty media between the printhead and platen.

Loading Roll Media

11

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12

Loading Roll Media

Placing the Roll in the Media Compartment

1. Open the printer. Remember that you need to pull the release latch levers toward the front

of the printer.

2. Open the media guides by turning the media guide adjustment knob toward the rear of the

printer.

P1039494-001 GC420d™ User Guide 8/15/2011

Loading Roll Media

3. Pull the media roll holders open with your free hand and place the media roll on the roll

holders and release. Orient the media roll so that its printing surface will face up as it
passes over the platen (drive) roller.

13

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14

Loading Roll Media

4. Pull the media so that it extends out of the front of the printer. Thread the media under the

media guides.Verify the roll turns freely. The roll must not sit in the bottom of the media
compartment. Verify that the media’s printing surface is facing up.

5. Close the media guides by turning the guide adjuster knob to the front. They should just

touch, but not restrict. the edges of the media.

6. Close the printer. Press down until the cover snaps closed.

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Printing a Test (Printer Configuration) Label

Printing a Test (Printer Configuration) Label

Before you connect the printer to your computer, make sure that the printer is in proper
working order.

You can do this by printing a configuration status label.

1. Make sure the media is properly loaded and the top cover of the printer is closed. Then,

turn the printer power on if you have not already done so. If the printer initializes with the
status light blinking green (pause mode), press the Feed button once to set the printer in
Ready (to print) mode. See the Troubleshooting on page 67 if the printer’s status light
does not turn solid green (Ready).

2. Press the Feed button two to three times to allow the printer to calibrate the printer for the

installed media. The printer may feed several labels during this process.

3. When the status light is solid green, press and hold the Feed button until the status light

flashes once.

4. Release the Feed button. A configuration label will print.

If you cannot get this label to print, refer to Getting Started on page 9.

15

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16

Pre-install Windows® Printer Drivers

Pre-install Windows® Printer Drivers

Zebra is changing the way you install and use your printer with your Windows based PC
systems. We recommend that at minimum, the ZebraDesigner™ Windows® driver be pre­installed to take advantage of the advancements in ease of use and simplicity of the Windows
operating systems since the release of Windows XP® SP2.

Zebra provides the Zebra Setup Utilities (ZSU); a suite of Zebra® printer drivers, utilities, and
communications and installation tools for use with most Windows PC operating systems.
Zebra Setup Utilities and Zebra Windows printer drivers are available on the user’s CD and the
Zebra web site (www.zebra.com) for latest versions.

ZebraDesigner™ Driver and Zebra Setup Utilities (includes the driver): Supports Windows
7®, Windows Vista®, Windows XP®, Windows® 2000®, Windows Server® 2008, and
Windows Server® 2003 operating systems. The driver supports 32 bit and 64 bit Windows
operating systems and is Microsoft Certified. Zebra Setup Utilities and the ZebraDesigner
driver support the following printer communication interfaces: USB, parallel, serial, Wired
and Wireless Ethernet and Bluetooth (using a Bluetooth virtual printer port).

Install the Zebra Setup Utilities before applying power to the printer connected to the PC
(running a Zebra driver supported Windows operating system). The Zebra Setup Utility will
prompt you to apply the printer power. Continue to follow the instructions to complete your
printer installation.

Plug’N’Play (PnP) Printer Detection and Windows® operating systems

More recent Windows operating systems automatically detect the printer when it is connected
via the USB interface. Depending on the hardware configuration and the Windows version,
your printer may be Plug-and-Play (PnP) detected when connecting to the USB, parallel, or
serial port interfaces. The printer drivers do not support serial port PnP installation at this
time.The printer’s PC interface configuration for the parallel port must support and have
bidirectional communications for PnP operations.

The operating system automatically starts a “Add new hardware’ wizard when connecting the
printer for the first time to the PC. If you have pre-loaded the driver suite with the Zebra Setup
Utility, then the printer driver will automatically install. Go to your Windows printer directory
and right-click and select ‘Properties’. Click on the ‘Print test page’ button to verify a
successful installation.

The Windows operating system will detect and re-link a previously installed printer if it is
reconnected to the USB interface or if printer power is turned on after the PC has finished its
restart of the operating system. Ignore the new device detected warnings and close the Task bar
prompts. Wait several seconds for the operating system to match the printer to the driver
software. The warnings will quit and the printer now should be ready to begin printing.

P1039494-001 GC420d™ User Guide 8/15/2011

Pre-install Windows® Printer Drivers

Universal Serial Bus (USB) Device Communications

The printer is a terminal device (not a host or hub) when using a USB interface. You can refer
to the USB Specification for details regarding this interface.

Scanners, scales or other data input (terminal) devices must use the serial port (not the USB
port) to send data to the printer.

Serial Port and Windows® operating systems

The Windows operating system default settings for the serial port communication closely
match the printer’s defaults settings with one exception; the data Flow Control settings. The
Windows default data Flow Control setting is NONE. The printer requires data Flow Control
set to Hardware.

®

Note • The printer does not support Windows

Serial Port Plug and Play (PnP) device

detection at this time.

Ethernet

17

This printer option has a variety of methods and utilities to assist with printer connection and
configuration of networked Zebra printers on a LAN (local area network) or WAN (wide area
network). The Zebra Setup Utility configuration wizards support creating a connection to the
printer on a shared network with Windows based systems by using the printer’s IP address.
The printer includes internal Web pages to provide easy access to printer and network
configuration. The web pages are accessible via the printers IP address using any web browser.
The free version of ZebraNet™ Bridge software allows you to centrally deploy, manage, and
monitor your Zebra® printers with automatic Zebra® printer discovery up to 3 printers from a
single PC screen anywhere on your global network. ZebraNet™ Bridge Enterprise is available
for purchase to manage larger numbers of Zebra® printers.

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18

Connecting your Printer to a Computer

Connecting your Printer to a Computer

The printer support a variety of interface options and configurations. These include: Universal
Serial Bus (USB) interface, RS232 Serial, Parallel (IEEE 1284.4) and 10/100 Ethernet.

• USB, Serial and Parallel

• Optional: USB and Ethernet (Wired)

The Zebra Setup Utility is designed to assist you with installing these interfaces. The
cabling and unique parameters for each of these physical printer communication interfaces is
discussed in the following pages to assist you with making configuration setup choices prior to
and immediately following applying power. The Zebra Setup Utilities configuration wizards
will instruct you to turn the printer’s power on at the appropriate time to complete the
installation of your printer.

Caution • Keep the power switch in the OFF position when attaching the interface cable.

The power cord must be inserted into the power supply and the power receptacle on the
back of the printer before connecting or disconnecting the communications cables.

Interface Cable Requirements

Data cables must be of fully shielded construction and fitted with metal or metallized
connector shells. Shielded cables and connectors are required to prevent radiation and
reception of electrical noise.

To minimize electrical noise pickup in the cable:

• Keep data cables as short as possible (6 foot [1.83 m] recommended).

• Do not tightly bundle the data cables with power cords.

• Do not tie the data cables to power wire conduits.

.

Important • This printer complies with FCC “Rules and Regulations,” Part 15, for Class B

Equipment, using fully shielded data cables. Use of un-shielded cables may increase radiated
emissions above the Class B limits.

P1039494-001 GC420d™ User Guide 8/15/2011

USB Interface Requirements

USB Cable

Universal Serial Bus (version 2.0 compliant) provides a fast interface that is compatible with
your existing PC hardware. USB’s “plug and play” design makes installation easy. Multiple
printers can share a single USB port/hub.

When using a USB cable (not supplied with your printer), verify that the cable or cable
packaging bears the “Certified USB™” mark (see below) to guarantee USB 2.0 compliance.

Connecting your Printer to a Computer

19

.

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20

Connecting your Printer to a Computer

Serial Communications

The GK888 has a DCE serial communication port for hardware compatibility with legacy 888
printers. The required cable must have a nine-pin “D” type (DB-9P) male connector on one
end which plugs into the mating (DB-9S) serial port located on the back of the printer. The
other end of this signal interface cable connects to a serial port on the host computer. The cable
is a Null-Modem (cross-over signal connections) cable. For pinout information, refer to
Appendix A.

The serial port communication settings between the printer and host (typically a PC) must
match for reliable communication. The Bits per second (or Baud rate) and Flow control are the
most common settings that get changed. The host (typically a Windows PC) needs to have the
data Flow control changed to match the printer’s default communication method: Hardware
and is noted by the Host Handshake setting DTR/Xon/Xoff. This combined hardware
(DTR) and software (Xon/Xoff) mode may need to change depending upon use with non­Zebra application software or the serial cable variation in use.

Serial communications between the printer and the host computer can be set by:

• Autobaud synchronization

• ZPL programming ^SC command

• EPL programming Y command

• Resetting the printer to its default printer configuration.

Autobaud

Autobaud synchronization allows the printer to automatically match the communication
parameters of the host computer. To autobaud:

1. Press and hold the feed button until the green status LED flashes once, twice, and then

three times.

2. While the status LED flashes, send the ^XA^XZ command sequence to the printer.

3. When the printer and host are synchronized, the LED changes to solid green. (No labels

will print during autobaud synchronization.)

ZPL ^SC Command

Use the Set Communications (^SC) command to change the communications settings on the
printer.

1. With the host computer set at the same communications settings as the printer, send the

^SC command to change the printer to the desired settings.

2. Change the host computer settings to match the new printer settings.

Refer to the ZPL Programming Guide for more information about this command.

P1039494-001 GC420d™ User Guide 8/15/2011

Connecting your Printer to a Computer

Serial Cable

EPL Y Command

Use the serial port setup (Y) command to change the communications settings on the printer.

1. With the host computer set at the same communications settings as the printer, send the

Y command to change the printer to the desired settings. Note: the Y command does not
support setting the data flow control, use the Xon/Xoff setting.

2. Change the host computer settings to match the new printer settings.

Refer to the EPL Page Mode Programming Guide for more information about this command.

Resetting the Default Serial Port Parameters

Do the following to reset the communications parameters on the printer to the factory defaults
(serial communication settings are: 9600 baud, 8 bit word length, NO parity, 1 stop bit, and
DTR/XON/XOFF data flow control).

1. Press and hold the feed button until the green status LED flashes once, waits a moment

and flashes twice, and then waits again before flashing three times (release
immediately).

2. While the status LED rapidly flashes amber and green, press the feed button. Serial

communications between the printer and the host computer can be set by the ZPL ^SC
command or the EPL Y command.

21

Note • Early models of Zebra

baud, NO

parity, 8 data bits, 1 stop bit and a HARDWARE and SOFTWARE (merged) data

®

printers running the EPL programming language had 9600

control (essentially DTR/Xon/Xoff) as the default serial port settings. The Windows operating
system flow control setting was Hardware for most applications.

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22

Parallel Cable

Connecting your Printer to a Computer

Parallel Port

The required cable must have a 25 pin “D” type (DB-25P) male connector (host) on one end
and a Centronics (printer) on the other end (IEEE 1284 A-B parallel interface specification).

P1039494-001 GC420d™ User Guide 8/15/2011

Ethernet

Ethernet Cable

(RJ45 Connector)

Green LED Amber LED

The printer requires UTP RJ45 Ethernet cable rated CAT-5 or better.

Connecting your Printer to a Computer

23

For more information on configuring your printer to run on a compatible Ethernet based

®

network, see the ZebraNet

10/100 Internal Print Server manual. The printer must be
configured to run on your LAN (local area network) or WAN (wide area network). The print
server on board your printer can be accessed through the printer’s Web pages.

Ethernet Status/Activity Indicators

LED Status Description

Both OFF No Ethernet link detected

Green 100 Mbps link detected

Green with the Amber

flickering on and off

Amber 10 Mbps link detected

Amber with the Green

flickering on and off

100 Mbps link and Ethernet activity detected

10 Mbps link and Ethernet activity detected

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24

After Your Printer is Connected

After Your Printer is Connected

Now that you have basic communication to your printer, you may want to test printer
communications and then install other printer related applications, drivers or utilities.

Testing Communications by Printing

Verifying the print system’s operation is a relatively simple process. For Windows operating
systems, the Zebra Setup Utility or the Windows ‘Printers and Faxes’ Control Panel to access
and print a test label. For non-Windows operation systems, copying a basic ASCII text file
with a single command (~WC) to the printer will print a configuration status label.

Test Printing with Zebra Setup Utility:

1. Open the Zebra Setup Utility.

2. Click on the newly installed printer’s icon to select the printer and activate the printer

configuration buttons below it in the window.

3. Click the ‘Open Printer Tools’ button.

4. In the ‘Print’ tab window, click on the ‘Print configuration label’ line and click on the

‘Send’ button. The printer should print a configuration status label.

Test Printing with Windows ‘Printer and Faxes’ menu:

1. Click on the Windows ‘Start’ menu button, to access the ‘Printers and Faxes’ menu or

‘Control Panel’ to access the ‘Printers and Faxes’ menu. Open the menu.

2. Select the newly installed printer’s icon to select the printer and right-click the mouse to

access the printer ‘Properties’ menu.

3. From the printer’s ‘General’ tab window, click on the ‘Print Test Page’ button. The printer

should print a Windows test print page.

Test Print on a Ethernet printer connected to a network (LAN or WAN) with a
(MS-DOS) ‘Command Prompt’ (or ‘Run’ from the Windows XP Start menu):

1. Create a text file with the following ASCII three characters: ~WC

2. Save the file as: TEST.ZPL (an arbitrary file name and extension name).

3. Read the IP address off the printer’s Configuration Status Label’s Network Status printout.

On a system that is connected to the same LAN or WAN as the printer, type the following
in the Web browser window’s address bar and enter:

fpt (IP address)

(for IP address 123.45.67.01 it would be: ftp 123.45.67.01)

4. Type the word ‘put’ followed by the file name and enter. For this ‘test print’ file, it would

be: put TEST.ZPL
The printer should print a new Print Configuration Status label.

P1039494-001 GC420d™ User Guide 8/15/2011

After Your Printer is Connected

Test Print with a Copied ZPL Command File for Non-Windows Operating Systems:

1. Create a text file with the following ASCII three characters: ~WC

2. Save the file as: TEST.ZPL (an arbitrary file name and extension name).

3. Copy the file to the printer. For DOS, a file sent to a printer connected to the system’s

parallel port would be as simple as:

COPY TEST.ZPL LPT1

Other interface connection types and operating systems will have different command
strings. See your operating system documentation for detailed instructions to copy to the
appropriate printer interface for this test.

25

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26

Notes • ___________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

After Your Printer is Connected

P1039494-001 GC420d™ User Guide 8/15/2011

3

Print Operations

This section provides media and print handling, font and language support, and the setup of
less common printer configurations.

Contents

Determining Printer Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Long Term Printer In-activity or Storage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Modes of Printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Print Media Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Replacing Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Adjusting the Print Width . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Adjusting the Print Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Media Sensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Printing on Fan-Fold Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Printing with Externally Mounted Roll Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Fonts and Your Printer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Stand Alone Printing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Sending Files to the Printer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Print Meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

EPL Line Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

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28

Determining Printer Configuration

Determining Printer Configuration

The printer uses a ZPL printer configuration status label to report the printer’s configuration
status for both EPL and ZPL operations.The ZPL style label provides a more intuitive and
functionally descriptive naming conventions than the EPL style printer status label.
Operational status (darkness, speed, media type, etc.), installed printer options (network,
interface settings, cutter, etc.) and printer description information (serial number, model name,
firmware version, etc.) are all includes on the status label. See Printing a Test (Printer

Configuration) Label on page 15 to print this label. See Appendix: ZPL Configuration
on page 91 for details on printer configuration and the ZPL commands that control the printer

settings listed on the Printer Configuration Status Label.

To get an EPL style printer configuration status label, send the printer the EPL U command.
See the EPL programmer’s guide for more information on the various EPL U commands and
interpreting the settings displayed on these labels.

Long Term Printer In-activity or Storage

Overtime the printhead may stick to the platen (drive) roller. To prevent this, always store the
printer with a piece of media (a label or paper) between the printhead and platen roller. Do not
ship the printer with a roll of media installed or damage to the printer or media may result.

Thermal Printing

Caution • The printhead becomes hot while printing. To protect from damaging the

printhead and risk of personal injury, avoid touching the printhead. Only use the cleaning
pen to perform printhead maintenance.

Caution • The discharge of electrostatic energy that accumulates on the surface of the

human body or other surfaces can damage or destroy the printhead or electronic
components used in this device. You must observe static-safe procedures when working
with the printhead or the electronic components under the top cover.

P1039494-001 GC420d™ User Guide 8/15/2011

Modes of Printing

You can operate this printer in many different modes and media configurations:

• Direct thermal printing (which uses heat sensitive media to print).

• Standard Tear-Off mode allows you to tear off each label (or batch print a strip of labels)
after it is printed.

• Label Dispense Mode: If an optional dispenser is installed, the backing material can be
peeled away from the label as it is printed. After this label is removed, the next one is
printed.

• Stand-alone: The printer can print without being connected to a computer using the
printer’s auto running label form feature (programming based) or by using a data input
device connected to the printer’s serial port. This mode accommodates data input devices,
such as scanners, weigh scales, Zebra
Unit), etc.

• Shared network printing: Printers configured with the Ethernet interface option include an
internal print server with ZebraLink™ printer configuration web page and ZebraNet™
Bridge software for managing and monitoring status of Zebra

Modes of Printing

®

KDU Plus™ or Zebra® KDU (Keyboard Display

®

printers on a network.

29

Print Media Types

Important • Zebra strongly recommends the use of Zebra-brand supplies for continuous

high-quality printing. A wide range of paper, polypropylene, polyester, and vinyl stock has
been specifically engineered to enhance the printing capabilities of the printer and to prevent
premature printhead wear. To purchase supplies, go to http://www.zebra.com/howtobuy.

Your printer can use various types of media:

• Standard media—Most standard (non-continuous) media uses an adhesive backing that
sticks individual labels or a continuous length of labels to a liner.

• Continuous roll media—Most continuous roll media is direct thermal media (similar to
FAX paper) and is used for receipt or ticket style printing.

• Tag s toc k—Tags are usually made from a heavy paper (up to 0.0075in./0.19mm thick).
Tag stock does not have adhesive or a liner, and it is typically perforated between tags.

For more information on basic media types, see Table 1.

The printer typically uses roll media, but you can use fan-fold or other continuous media too.
Use the correct media for the type of printing you require. You must use direct thermal media.

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30

Print Media Types

Table 1 • Types of Media Roll and Fanfold Media

Media Type How It Looks Description

Non-Continuous
Roll Media

Roll media is wound on a core that can be 0.5 to 1.5 in. (12.7 to

38.1 mm) in diameter. Labels have adhesive backing that sticks
them to a liner, and they are separated by gaps, holes, notches, or
black marks. Tags are separated by perforations. Individual labels
are separated by one or more of the following methods:

• Web m ed i a separates labels by gaps, holes, or notches.

• Black mark media uses pre-printed black marks on the back
side of the media to indicate label separations.

Non-Continuous
Fanfold Media

Continuous
Roll Media

• Perforated media has perforations that allow the labels or tags
to be separated from each other easily. The media may also
have black marks or other separations between labels or tags.

Fan-Fold media is folded in a zigzag pattern. Fanfold media can
have the same label separations as non-continuous roll media.
The separations would fall on or near the folds.

Roll media is wound on a core that can be 0.5 to 1.5 in. (12.7 to

38.1 mm) in diameter. Continuous roll media does not have gaps,

holes, notches, or black marks to indicate label separations. This
allows the image to be printed anywhere on the label. A cutter
can be used to cut apart individual labels. With continuous media,
use the transmissive (gap) sensor so the printer can detect when
the media runs out.

P1039494-001 GC420d™ User Guide 8/15/2011

Determining Thermal Media Types

Thermal transfer media requires ribbon for printing while direct thermal media does not.
To determine if ribbon must be used with a particular media, perform a media scratch test.

To perform a media scratch test, complete these steps:

1. Scratch the print surface of the media with a finger nail or pen cap. Press firmly and

quickly while dragging it across the media surface. Direct thermal media is chemically
treated to print (expose) when heat is applied. This test method uses friction heat to expose
the media.

2. Did a black mark appear on the media?

If a black mark... Then the media is...

Does not appear on the media Thermal transfer. A ribbon is required. Your printer

Appears on the media Direct thermal. No ribbon is required.

Replacing Supplies

31

does not support this media.

Replacing Supplies

If labels run out while printing, leave the printer power on while reloading (data loss results if
you turn off the printer). After you re-load media, press the Feed button to restart.

Always use high quality, approved labels and tags. If adhesive backed labels are used that
don’t lay flat on the backing liner, the exposed edges may stick to the label guides and rollers
inside the printer, causing the label to peel off from the liner and jam the printer.

Adjusting the Print Width

Print width must be set when:

• You are using the printer for the first time.

• There is a change in media width.

Print width may be set by:

• The Windows printer driver or application software such as ZebraDesigner™.

• The five-flash sequence in Feed Button Modes on page 78.

• Controlling printer operations with ZPL programming; refer to the Print Width (^PW)

command (consult your ZPL Programming Guide).

• Controlling printer operations with EPL Page Mode programming, refer to the Set Label
Width (

8/15/2011 GC420d™ User Guide P1039494-001

q) command (consult your EPL Programmer’s Guide).

32

Adjusting the Print Quality

Adjusting the Print Quality

Print quality is influenced by the heat (density) setting of the printhead, the print speed, and the
media in use. Experiment with these settings to find the optimal mix for your application. Print
quality can be set with the Zebra Setup Utility’s ‘Configure Print Quality’ routine.

Note • Media manufactures may have specific recommendations for speed settings for your
printer and the media. Some media types have lower maximum speeds than your printer’s
maximum speed.

The relative darkness (or density) setting can be controlled by:

• The six-flash sequence in Feed Button Modes on page 78. This will overwrite any ZPL
and EPL programmed darkness/density settings.

• The Set Darkness (

~SD) ZPL command (consult your ZPL Programming Guide).

• The Density (D) EPL command (consult your EPL Programmer’s Guide).

If you find that the print speed needs to be adjusted, use:

• The Windows printer driver or application software such as ZebraDesigner™.

• The Print Rate (^PR) command (consult your ZPL Programming Guide).

• The Speed Select (

S) command (consult your EPL Programmer’s Guide).

P1039494-001 GC420d™ User Guide 8/15/2011

Media Sensing

The printer has automatic media sensing capability. The printer is designed to continuously
check and adjust media length sensing for minor variations. Once the printer is printing or
feeding media, the printer continually checks and adjusts the media sensing to accommodate
for minor changes in media parameters from label to label on a roll and from roll to roll of
media. The printer will automatically initiate a media length calibration if the expected media
length or the label to label gap distance has exceeded the acceptable variation range when
starting a print job or feeding media. The automatic media sensing in the printer works the
same for printer operations that use EPL and ZPL label formats and programming.

If the printer does not detect labels or black marks (or notches with blackline sensing) after
feeding the media the default maximum label length distance of 39 inches (1 meter), then the
printer will switch to continuous (receipt) media mode. The printer will keep these settings
until changed by software, programming or a manual calibration with different media.

Optionally, the printer can be set to do a short media calibration after printer power up or when
closing the printer with power on. The printer will then feed several labels while calibrating.

The printer’s media settings can be verified by printing a Printer Configuration label. See the

Printing a Test (Printer Configuration) Label on page 15 for more details.

Media Sensing

33

The maximum distance that the automatic media type detection and sensing will check can be
reduced by using the ZPL Maximum Label Length command (^ML). It is recommended that
this distance be set to no less than two times the longest label being printed. If the largest label
being printed was a 4 by 6 inch label, then the maximum label (media) length detection
distance can be reduced from the default distance of 39 inches down to 12 inches.

If the printer has difficulty automatically detecting the media type and auto-calibrating, see

Manual Calibration on page 74 to perform an extensive calibration. It includes a printed graph

of sensor operation for your media. This method disables the printer’s automatic media
sensing capability until the printer’s default parameters are reset to the factory defaults with
the four flash Feed button mode. See the Feed Button Modes on page 78 for more details.

The automatic media calibration can be modified, turned on or turned off to meet your needs.
Sometimes print job conditions require that the printer use all the media on a roll. The two
automatic media conditions, power up with media loaded and closing the printer with power
on, can be controlled individually with the ZPL Media Feed command, ^MF. The feed action
discussed in the ZPL programmers guide for the ^MF command is primarily for automatic
media sensing and calibration. The automatic media calibration that controls the dynamic
media (label to label) calibration is the ^XS command. If multiple media types of different
lengths, material or detection methods (web/gap, black mark, notches or continuous) are used,
you should not change these settings.

The media calibration and detection process can also be refined to match the media type
loaded into the printer. Use the ZPL Media Tracking command (^MN) to set the media type.
Sometimes the printer can detect preprinted media as the gap between labels or the liner
backing with print as a black marks. If the ^MN parameter for continuous media is set, then the
print does not preform the automatic calibration. The ^MN command also includes an
automatic calibration parameter (^MNA) to return the printer to its default setting to
automatically detect all media types.

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34

Printing on Fan-Fold Media

Printing on Fan-Fold Media

Printing on fan-fold media requires you to adjust the media roll holders’ stop position.

1. Open the top cover.

2. With a sample of your media, adjust the media roll holders to the width of the media. The

hangers should just touch, but not restrict, the edges of the media.Tighten the screw using
a small Phillips driver #1.

P1039494-001 GC420d™ User Guide 8/15/2011

Printing on Fan-Fold Media

3. With a sample of your media, adjust the guides to the width of the media.The guides

should just touch, but not restrict, the edges of the media.

35

4. Run the media between the media guide and roll holders.

5. Close the top cover.

After printing or feeding several labels: If the media does not track down the center (moves
from side to side) or the sides of the media (liner, tag, paper, etc.) are frayed or damaged when
exiting the printer, then the media guides or roll holders may need further adjustment.

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36

Printing with Externally Mounted Roll Media

Printing with Externally Mounted Roll Media

The GC420 printer accommodates externally mounted roll media similar to the printer’s
support of fan-fold media. The printer requires the media roll and stand combination to have a
low initial inertia to pull the media off the roll.

Zebra at this time does not offer an external media option for the GC420 printer.

Externally Mounted Roll Media Considerations:

• The media ideally should enter the printer directly behind the printer through the fan-fold
media slot in the rear of the printer. See Printing on Fan-Fold Media on page 34 for media
loading.

• Lower the print speed to decrease the chance of motor stalls. The roll typically has the
highest inertia when trying to start the roll moving. Larger media roll diameters require the
printer to have more torque applied to get the roll moving.

• The media should move smoothly and freely. The media should not slip, skip, jerk, bind
and then move, etc. when mounted on your media stand.

• The printer should not touch the media roll.

• The printer should not slip or lift up off the operating surface.

P1039494-001 GC420d™ User Guide 8/15/2011

Fonts and Your Printer

The GC420 printer supports your language and font requirements with a variety of internal
fonts, on-board font scaling, international font sets and character code page support, Unicode
support, and font download.

The GC420 printer’s font capabilities are programming language dependent. The EPL™
programming language provides for basic bitmapped fonts and international code pages. The
ZPL™ programming language provides advanced font mapping and scaling technology to
support outline fonts (TrueType™ or OpenType™) and Unicode character mapping as well as
basic bitmapped fonts and character code pages. ZPL and EPL programming guides describe
and document the fonts, code pages, character access, listing fonts, and limitations for their
respective printer programming languages. See the printer programming guides for
information on Text, Fonts and Character support.

The GC420 printer includes utilities and application software that support font download into
the printer for both printer programming languages.

Fonts and Your Printer

37

Localizing the Printer with Code Pages

The GC420 printer supports two sets of language, region and character sets for permanent
fonts loaded into the printer for each printer programming language, ZPL and EPL. The printer
supports localization with common international character map code pages.

• For ZPL code page support, including Unicode, see the ^CI command in the ZPL
programmer’s guide.

• For EPL code page support, see the I command in the EPL programmer’s guide.

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38

Fonts and Your Printer

Identifying Fonts in Your Printer

Fonts and memory are shared by the programming languages in the printer. Fonts can be
loaded in many memory areas in the GC420 printer. ZPL programming can recognize EPL and
ZPL fonts. EPL programming can only recognize EPL fonts. See the respective programmer
guides for more information on fonts and printer memory.

ZPL Fonts:

• To manage and download fonts for ZPL print operation, use the Zebra Setup utility or
ZebraNet™ Bridge.

• To display all of the fonts loaded in your printer, send the printer the ZPL ^WD command.
See the ZPL Programmers Guide for details.

• Bitmap fonts in the various printer memory areas are identified by the .FNT file
extension in ZPL.

• Scalable fonts are identified with the .TTF, .TTE or .OTF file extensions in ZPL.
EPL does not support these fonts.

EPL Fonts:

• To download fonts for EPL print operations, use the Zebra Setup Utility or ZebraNet™
Bridge to send files to the printer.

• To display Soft Fonts (ext.) available to EPL, send the printer the EPL command EI.

• All EPL fonts displayed are bitmap fonts. They do not include the .FNT file extension
or the horizontal (H) or vertical (V) designators that are displayed with the ZPL
command ^WD as described above in ZPL Fonts.

• To remove non Asian EPL fonts with EPL programming, use the EK command.

• To remove EPL Asian fonts from the printer, use the ZPL ^ID command.

P1039494-001 GC420d™ User Guide 8/15/2011

Stand Alone Printing

Your printer can be configured to work without being attached to a computer. The printer has
the ability to automatically run a single label form. One or more downloaded label forms can
be accessed and run with a terminal or wedge device or a Zebra
to call a label form. These methods allow the developer to incorporate data input devices, such
as scanners or weight scales, to the printer via the serial port.

Label formats can be developed and stored in the printer to support labels that have:

• No data entry required and print when the Feed button is pressed.

• No data entry required and print when a label is removed from the printer’s optional label
dispenser.

• One or more data variables to be entered via the terminal or wedge device. The label will
print after the last variable data field has been input.

• One or more label formats that are called by scanning bar codes containing programming
to run a label form.

• Label forms designed to work as a process chain with each label including a bar code
containing the programming to run the next label in the process sequence.

Stand Alone Printing

®

KDU (keyboard display unit)

39

Both printer programming languages support special label forms that will automatically run
after a power cycle or reset. The ZPL looks for a file named AUTOEXEC.ZPL and EPL
looks for a label form named AUTOFR. If both files are loaded in the printer, then only the
AUTOEXEC.ZPL will run. The EPL AUTOFR form runs until it is disabled. Both files must
be deleted from the printer followed by a reset or a power cycle to completely remove the files.

Note • The GC420 EPL AUTOFR command can only be disabled with NULL character (00 hex
or ASCII 0). The printer will ignore the other character that normally disables the AUTOFFR
form operation in most other EPL printers, the XOFF character (13 hex or ASCII 19).

The printer can source up to 750mA through a 5 volt line shared between the parallel and serial
ports. See Appendix A for more information on the printer’s serial port interface.

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40

Sending Files to the Printer

Sending Files to the Printer

Graphics, fonts and programming files can be sent to the printer from the Microsoft Windows
operating systems by using the Zebra Setup Utilities (and driver), ZebraNet™ Bridge or

®

Zebra
common for both programming languages and the GC420 printers.

ZDownloader found on the user's CD or at www.zebra.com. These methods are

Print Meter

The GC420 printer has the capability to report printhead maintenance alerts. The printer can
provide cleaning and early warning of end of calculated printhead life alerts. If the RTC (Real
Time Clock) is installed in the printer, the printhead life and history reporting will also include
the date. By default, print metering alerts are disabled.

Many of the print meter messages and reports are customize able. See the ZPL or EPL
Programming Guides for more information on the Print Meter.

To active the Print Meter Alerts, send one of the following commands to the printer:

• EPL command oLY

• ZPL command ^JH,,,,,E

EPL Line Mode

Your direct thermal printer supports Line Mode printing. EPL Line Mode printing is designed
to be command compatible with EPL1 programming language used in early model LP2022
and LP2042 printers. The Zebra 2800 series direct thermal printers also included Line Mode
printer language support. The GC420 continues Zebra’s support of Line Mode.

Line mode printing is ideal for basic retail (point of sale - POS), shipping, inventory, work
flow control, and general labeling. EPL printers with Line Mode, are versatile and are capable
of printing a wide range media and bar codes.

Line Mode printing only prints single lines the height of the largest element present in the line
of text and data - bar code, text, a logo or simple vertical lines. Line mode has many
limitations due to the single line of print: no fine element placement, no overlapping elements,
and no horizontal (ladder) bar codes.

• Line Mode printer operation is entered by sending the printer the EPL OEPL1 command.
See the EPL Programmers Guide (Page Mode) or the EPL Line Mode Programmers
Guide.

• Line Mode printer operation is exited by sending the printer the escOEPL2 Line Mode
command. See the EPL Line Mode Programmers Guide.

• With Line Mode active, ZPL and EPL (EPL2) Page Mode programming will be processed
as Line Mode programming and data.

• With the default ZPL and EPL (EPL2) Page Mode active, Line Mode programming will
be processed as ZPL and/or EPL programming and data.

• Verify printer programming modes by printing out a printer configuration.

P1039494-001 GC420d™ User Guide 8/15/2011

4

Printer Options

This section covers the common printer options and accessories with brief descriptions and
how to get you started using or configuring your printer option or accessory.

Contents

Label Dispenser Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

ZebraNet® 10/100 Internal (Wired) Print Server Option . . . . . . . . . . . . . . . . . . . . . . . . . 49

Zebra® KDU — Printer Accessory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

KDU Plus™ — Printer Accessory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

ZBI 2.0™ — Zebra Basic Interpreter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

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42

Label Dispenser Option

Label Dispenser Option

The factory installed label dispenser option allows you to print a label with backing
(liner/web) being removed from the label as it prints, ready for application. When printing
multiple labels, removing the dispensed (peeled) label notifies the printer to print and dispense
the next label.

To use dispenser-mode correctly, use your printer driver to activate the label (taken) sensor
along with these typical label settings which include but are not limited to length, non­continuous (gap), and web (liner). Otherwise, you must send the ZPL or EPL programming
commands to the printer.

When programming in ZPL, you can use the following command sequences shown below
and refer to your ZPL Programming Guide for more information on ZPL programming.

When programming in EPL, send the Options (O) command with the ‘P’ command
parameter (
included with the Options command string. Refer to your EPL Programmer’s Guide for more
information on programming with EPL and the Options (

OP) to enable the Label Taken sensor. Other printer option parameters may also be

^XA ^MMP ^XZ

^XA ^JUS ^XZ

O) command behaviors.

1. Load your labels into the printer. Close the printer and press the Feed button until a

minimum of 4 inches or 100 millimeters of exposed labels exit the printer. Remove the
exposed labels from the liner.

P1039494-001 GC420d™ User Guide 8/15/2011

2. Lift the liner over the top of the printer and open the dispenser door.

Label Dispenser Option

43

3. Insert the label liner between the dispenser door and the printer body.

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44

Label Dispenser Option

4. Close the dispenser door.

5. Press the Feed button to advance the media.

6. During the print job, the printer will peel off the backing and present a single label. Take

the label from the printer to allow the printer to print the next label. Note: If you did not
activate the label taken sensor to detect the removal of the dispensed (peeled) label with
software commands, the printer will stack and eject peeled labels.

P1039494-001 GC420d™ User Guide 8/15/2011

Cutter Option

The printer supports a factory installed media cutter option for full width cutting of label liner,
tag or receipt media. These cutter options are all supported in a single cutter housing design.
The type of cutter option installed in your printer can be verified by printing a printer
configuration status label. The cutter options are:

• A medium duty cutter for cutting label liner and light tag media (LINER/TAG)

• Cut Width: 4.25 inches (108 mm) maximum to 0.75 inches (19 mm) minimum

• Minimum distance between cuts (label length): 1 inch (25.4 mm). Cutting shorter

• By default, the cutter operations include a self cleaning preventive maintenance

Cutter Option

Maximum Paper Weight (thickness): up to 180 g/m2 (0.0077 in.)
Life*: 2 million cuts: 0.5 mil to 5 mil stock (10-120 g/m2)

1 million cuts: 5 mil to 7.5 mil stock (120-180 g/m2)

750,000 cuts: 7.5 mil to 10 mil (180-200 g/m2)

* - Exceeding the maximum media weight (density/hardness) and thickness will

shorten the cutters usable life or can cause the cutter to fail (jam or other error).

media lengths between the cuts may cause the cutter to jam or error.

cleaning cut after every twenty-fifth cut. This feature can be disabled via ZPL or EPL
SGD (Set/Get/DO) programming command (
recommended.

cutter.clean_cutter) but is not

45

Warning • There are no operator serviceable parts in the cutter unit. Never remove the

cutter cover (bezel). Never attempt to insert objects or fingers in to the cutter mechanism.

Important •

the cutter’s usable life or cause the cutter to jam.

Tools, cotton swabs, solvents (including alcohol), etc. all may damage or shorten

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46

Cutter Option

Loading Media with the Cutter Option

1. Open the printer. Remember that you need to pull the release latch levers toward the front

of the printer.

2. Open the media guides by turning the media guide adjustment knob toward the rear of the

printer.

P1039494-001 GC420d™ User Guide 8/15/2011

Cutter Option

3. Open the media roll holders. Pull the media guides open with your free hand and place the

media roll on the roll holders and release the guides. Orient the media roll so that its
printing surface will be up as it passes over the platen (drive) roller.

.

47

4. Thread the media through the cutter’s inside slot so that it extends out of the front of the

printer. Verify the roll turns freely. The roll must not sit in the bottom of the media
compartment. Verify that media’s printing surface is facing up.

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48

Cutter Option

5. Close the media guides by turning the guide adjuster knob to the front. They should just

touch, but not restrict. the edges of the media..

6. Close the printer. Press down until the cover snaps closed.

P1039494-001 GC420d™ User Guide 8/15/2011

ZebraNet® 10/100 Internal (Wired) Print Server Option

ZebraNet® 10/100 Internal (Wired) Print Server Option

49

The ZebraNet® 10/100 Internal Print Server (PS) is an optional factory installed device that

TM

connects the network and your ZebraLink
with a browser interface for printer and print server settings. If you use the ZebraNet

-enabled printer. The print server provides you

TM

Bridge

Zebra network printer management software, you can easily access the specialized features of

TM

a ZebraLink

enabled printer.

Printers with the 10/100 Internal PS provide the following features:

• Print server and printer setup using a browser

• Remote monitoring and configuration capability of the 10/100 Internal PS using a
browser

•Alerts

• The ability for you to send unsolicited printer status messages via E-mail-enabled
devices

TM

ZebraNet

Bridge — ZebraNetTM Bridge is a software program that works with the
10/100 Internal PS and enhances the features of ZebraLink resident within ZPL-based printers.
The features include the following:

TM

•ZebraNet

Bridge allows you to locate printers automatically. ZebraNetTM Bridge
searches on parameters such as IP address, subnet, printer model, printer status, and
many other user-defined characteristics.

• Remote Configuration — Manage all your Zebra label printers throughout the
enterprise without having to travel to remote sites or physically handle any printers.
Any Zebra printer connected to the enterprise network can be accessed from the

TM

ZebraNet

Bridge interface and configured remotely through an easy-to-use

graphical user interface.

TM

• Printer Alerts, Status, Heartbeat Monitoring and event Notification — ZebraNet
Bridge lets you configure multiple event alerts per device with different alerts directed
to different people. Receive alerts and notifications by e-mail, cell phone/pager, or

TM

through the ZebraNet

Bridge Events tab. View alerts by printer or group, and filter

by date/time, severity, or trigger.

• Configure and Copy Printer Profiles — Copy and paste settings from one printer to
another or broadcast them to an entire group. ZebraNet™ Bridge allows you to copy
printer settings, printer-resident files (formats, fonts, and graphics), and alerts with a
click of the mouse. Create printer profiles — virtual “golden printers” — with desired
settings, objects, and alerts, and clone or broadcast them as if they were real printers,
providing extensive savings in setup time. Printer profiles are also an excellent way to
back up a printer’s configuration for crisis recovery.

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50

ZebraNet® 10/100 Internal (Wired) Print Server Option

Printer Network Configuration Status Label

GC420 printers with the ZebraNet® 10/100 Internal Print Server option on-board print an
additional printer configuration status label for information needed to establish and trouble
shoot network printing. The following printout is printed with the ZPL

~WL command.

The regular printout of the configuration status label has some of the printer’s network settings
such as IP Address, on the lower half of the printout.

The printer’s IP address is needed to identify and configure the printer for operations on your
network. See the ZebraNet

®

10/100 Internal Print Server manual for more information.

P1039494-001 GC420d™ User Guide 8/15/2011

Zebra® KDU — Printer Accessory

The KDU (keyboard display unit) is a small terminal unit that interfaces with the printer for
accessing EPL label forms stored in the printer.

The KDU is strictly a terminal and does not have the capability to store data or set up
parameters. The KDU is used for the following functions:

• List label forms stored in printer

• Retrieve label forms stored in printer

• Input variable data

• Printing labels

Zebra® KDU — Printer Accessory

51

v

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52

45mA*

120mA*

25mA*

( 45mA + 120mA + 25mA ) + 50mA < Max. Current

50mA

* - Not real values

Current Draw

KDU Plus™ — Printer Accessory

KDU Plus™ — Printer Accessory

The KDU Plus is a terminal device with memory for storing files and maintaining one or more
remote printers. The KDU Plus has a larger laptop style keyboard than the Zebra’s original
KDU design.

The KDU Plus is designed for the following functions:

• List label forms stored in printer

• Retrieve label forms stored in printer

• Input variable data

• Printing labels

• File storage and transfer

The KDU Plus is designed to work with ZPL and EPL printers by dynamically detecting and
switching the printer’s communications configuration (DTE or DCE) to match your Zebra
printer. By default, the KDU Plus will start up forms mode. This is compatible with the
operation of Zebra’s original KDU. The KDU Plus is configurable to work in ZPL or terminal
modes too.

The KDU Plus has file transfer and storage capabilities. This is great for maintaining remote
and stand alone printers with label forms, logos and smaller font sets.

The KDU Plus has two configurable serial port and a PS/2 port to connect to other data input
devices such as scanners, weigh scales, etc..

The +5 volts from the printer’s serial (pin 9) provides power for the KDU Plus and any
additional input devices attached to the KDU Plus.

Maximum total current draw for the GC420 printer’s serial (and parallel) port: 750mA
The KDU Plus’s current without external input devices attached is: 50mA

Caution • The KDU Plus’s input ports (AUX1, AUX2, and PS/2 style) are not fused.

P1039494-001 GC420d™ User Guide 8/15/2011

Exceeding the total current draw available could damage an input device, KDU Plus, or
the printer.

ZBI 2.0™ — Zebra Basic Interpreter

Customize and enhance your printer with ZBI 2.0 optional programming language,
ZBI 2.0 allows Zebra printers to run applications and take input from scales,
scanners and other peripherals—all without a PC or network connection. ZBI 2.0
works with the ZPL printer command language so that printers can understand
non-ZPL data streams and convert them into labels. That means the Zebra printer
can create bar codes and text from input received, non-ZPL label formats, sensors,
keyboards and peripherals. Printers can also be programmed to interact with PC
based database applications to retrieve information to be used on printed labels.

ZBI 2.0 can be activated by ordering a ZBI 2.0 Key Kit, or activated by purchasing a key from
the ZBI 2.0 store at www.zebrasoftware.com

Use the ZDownloader utility to apply the key. Zdownloader is available on the users CD or at
the Zebra Web site: www.zebra.com

.

An intuitive ZBI-Developer™ programming utility is used to create, test and
distribute ZBI 2.0 applications is available on the users CD or at the Zebra Web site:

www.zebra.com

.

.

ZBI 2.0™ — Zebra Basic Interpreter

53

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54

Notes • ___________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

ZBI 2.0™ — Zebra Basic Interpreter

P1039494-001 GC420d™ User Guide 8/15/2011

Maintenance

This section provides routine cleaning and maintenance procedures.

5

Contents

Cleaning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Cleaning the Printhead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Media Path Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Platen Cleaning and Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Other Printer Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Replacing the Printhead. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

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56

Cleaning

Cleaning

When you clean the printer, use one of the following supplies that best suits your needs:

Cleaning Supplies

Order

Quantity

Intended Purpose

Cleaning pens (105950-035) Set of 12 Clean printhead

Cleaning swabs (105909-057) Set of 25 Clean media path, guides and sensors

You can obtain cleaning supplies at

www.zipzebra.com.

The cleaning process takes just a couple of minutes using the steps outlined below.

Printer Part Method Interval

Printhead Let the printhead to cool for a minute, then use a

new cleaning pen to swab the dark line on the

After every roll of

media.
printhead cleaning from the center to the outside
edges of the printhead.
See Cleaning the Printhead on page 57

Platen roller Remove the platen roller to clean. Clean the

As needed.
roller thoroughly with 90% medical-grade
alcohol and a cleaning swab or lint-free cloth.
See Platen Cleaning and Replacement

on page 60

Peel bar Clean it thoroughly with 90% medical-grade

Media path

alcohol and a fiber-free cleaning swab.

Let alcohol dissipate and the printer dry
completely.

Exterior Water-dampened cloth.

Interior Gently brush out printer.

Caution • Adhesives and media material can over time transfer onto the printer

components along the media path including the platen and printhead. This build-up can
accumulate dust and debris. Failure to clean the printhead, media path and platen roller
could result in inadvertent loss of labels, label jams and possible damage to the printer.

Important • Using too much alcohol can result in contamination of the electronic

components requiring a much longer drying time before the printer will function properly.

P1039494-001 GC420d™ User Guide 8/15/2011

Cleaning the Printhead

Always use a new cleaning pen on the printhead (an old pen carries contaminants from its
previous uses that may damage the printhead).

Caution • The printhead becomes hot while printing. To protect from damaging the

printhead and risk of personal injury, avoid touching the printhead. Use only the cleaning
pen to perform maintenance.

When you load new media, you can also clean the printhead.

1. Rub the cleaning pen across the dark area of the printhead. Clean from the middle to the

outside. This will move adhesive transferred from the edges of media to the printhead
outside of media path.

2. Wait one minute before closing the printer.

Cleaning

57

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58

Media

Guides

Platen

Peel

Bar

Pinch

Roller

Ridges

Cleaning

Media Path Considerations

Use a cleaning swab to remove debris, dust or crust that has built-up on the holders, guides and
media path surfaces.

1. Use the alcohol in the cleaning swab to soak the debris to break up the adhesive.

2. Wipe the ridges to remove accumulated debris.

3. Wipe the inside edges of both edge guides to remove any built-up residue.

4. Wait one minute before closing the printer.

Discard the cleaning swab after use.

P1039494-001 GC420d™ User Guide 8/15/2011

Sensor Cleaning

Black-Line

Sensor

Gap

Sensor

Label Taken

Sensor

Dust can accumulate on the media sensors.

1. Gently brush away dust; if necessary, use a dry swab to brush away dust. If adhesives or

other contaminates remain, use an alcohol moistened swab to break it up.

2. Use a dry swab to remove any residue that may be left from the first cleaning.

Cleaning

59

3. Repeat steps 1 and 2 as required until all residue and streaks are removed from the sensor.

.

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60

Cleaning

Platen Cleaning and Replacement

The standard platen (drive roller) normally does not require cleaning. Paper and liner dust can
accumulate without effecting print operations. Contaminates on the platen roller can damage
the printhead or cause the media to slip or stick when printing. Adhesive, dirt, general dust,
oils and other contaminates should be cleaned immediately off the platen.

Clean the platen (and media path) whenever the printer has significantly poorer performance,
print quality or media handling. The platen is the print surface and drive roller for your media.
If sticking or jamming continues even after cleaning, you must replace the platen.

The platen can be cleaned with a fiber-free swab (such as a Texpad swab) or a lint free, clean,
damp cloth very lightly moistened with medical grade alcohol (90% pure or better).

1. Open the cover (and dispenser door). Remove media from platen area.

2. Using a pointed stylus (such as tweezers, small slot-head screwdriver, or razor-knife),

unhook the tabs on the right and left sides. Then rotate them forward.

3. Lift the platen out of the printer’s bottom frame.

4. Clean the platen with the alcohol moistened swab. Clean from the center out. Repeat this

process until the all of the roller surface has been cleaned. If there has been heavy
adhesive build-up or label jam, repeat with a new swab to remove residual contaminates.
Adhesives and oils, for example, may be thinned by the initial cleaning but not completely
removed.

P1039494-001 GC420d™ User Guide 8/15/2011

Cleaning

5. Install the platen in the printer. Discard the cleaning swabs after use - do not reuse.

6. Make sure the bearings and gear are on the shaft of the platen as shown.

7. Align the platen with the gear to the left and lower it into the printer’s bottom frame.

61

8. Rotate the tabs back and snap them into place.

Allow the printer to dry for one minute before closing the dispenser door, media cover or
loading labels.

Other Printer Maintenance

There are no user level maintenance procedures beyond those detailed in this section. See the
Troubleshooting on page 67 for more information on diagnosing printer and print problems.

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62

Replacing the Printhead

Replacing the Printhead

If you need to replace the printhead, read the procedure and review the removal and
installation steps before actually replacing the printhead.

Caution • Prepare your work area by protecting against static discharge. Your work area

must be static-safe and include a properly grounded conductive cushioned mat to hold the
printer and a conductive wrist strap for yourself.

Caution • Turn the printer power off and unplug the power cord before replacing the

printhead.

Before following the steps in this procedure, open the printer by pulling the release latches
forward then lifting the top cover.

Printhead Removal

1. Use a #1 Phillips driver to loosen the four screws that hold the latch frame to the top case.

P1039494-001 GC420d™ User Guide 8/15/2011

Replacing the Printhead

2. Grasp the print head spring and pull it to the left; then, slide it free of the latch frame.

63

3. Gently pull the wire bundles from the printhead.

4. Use a #1 Phillips driver to loosen the two screws and washers and release the print head

from the latch frame and bracket.

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64

Replacing the Printhead

Printhead Installation

1. Route the print head cables under the latch shaft and plug the printhead cables into the

receptacles on the printhead.

2. Hold the printhead against the bracket while replacing the screws and washers. Attach the

ground wire using the right screw and washer. Use a #1 Phillips driver to tighten the
screws.

P1039494-001 GC420d™ User Guide 8/15/2011

Replacing the Printhead

3. Slip the left end of the printhead spring into the left side of the latch bracket; then slide the

right end into the other side. The angle of the “V” fits into the indent on the top of the
printhead bracket.

65

4. Align the latch bracket up to the top case and ensure that the cable are not bent or pinched.

5. Replace the four screws that hold the latch bracket to the top case and use a #1 Phillips

driver to tighten them.

6. Clean the print head as described under Cleaning the Printhead on page 57.

7. Reload media. Plug in the power cord, turn on the printer and print a status report to

ensure proper function. See Printing a Test (Printer Configuration) Label on page 15

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66

Notes • ___________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

Replacing the Printhead

P1039494-001 GC420d™ User Guide 8/15/2011

6

Troubleshooting

This section provides information about printer error reporting that you might need for printer
troubleshooting. Assorted diagnostic tests are included.

Contents

Status Light Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Status Light Error Resolutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Print Quality Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Manual Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Troubleshooting Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Resetting the Factory Default Values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Communications Diagnostics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Feed Button Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

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68

Status Light Descriptions

Status Light Descriptions

What the Status Light is Telling You

LED Status and Color Printer Status

For a Resolution,
Refer to Number:

Off Off 1

Solid Green On 2

Solid Amber Stopped 3

Flashing Green Normal Operation 4

Flashing Red Stopped 5

Double Flashing Green Paused 6

Flashing Amber Paused 7

Alternately Flashing Green and Red Needs Service 8

Flashing Red, Red and Green Needs Service 9

Flashing Red, Amber Green

(* - Do NOT reset or turn off power!)

Memory

Defragmentation

10*

P1039494-001 GC420d™ User Guide 8/15/2011

Status Light Error Resolutions

The following Status Error Light Resolution numbers correspond to the Status Light
Description table on the previous page. Each error number may have one or more resolution to
correct that error listed.

1. The printer is not receiving power.

• Have you turned on the printer power?

• Check power connections from the wall outlet to the power supply, and from the power
supply to the printer. See Attaching Power on page 10.

• Disconnect the printer from the wall outlet for 30 seconds and then reconnect the printer to
the wall outlet.

2. The printer is on and in an idle state.

No action necessary.

Status Light Error Resolutions

69

3. The printer has failed its power on self test (POST).

• If this error occurs right after you turn on the printer, contact an authorized reseller for
assistance. When the printer is operating normally, the printer status light will be amber
for about 10 seconds before turning green (solid or blinking).

There is a memory error.

• If this error occurs after you have been printing, turn the printer power off and on, and
then resume printing.

The printhead needs to cool down.

• If this error continues, turn the printer power off for five minutes or more, and then turn
on. If the amber light persists, then the printer requires service.

4. The printer is receiving data.

• As soon as all of the data has been received, the status LED will turn green and the printer
will automatically resume operation.

5. The media is out.

• Follow the instructions for Loading Roll Media on page 11 in the Getting Started section,
and then press the Feed button to resume printing.

The printhead is open.

• Close the top cover and then press the Feed button to resume printing.

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70

Status Light Error Resolutions

6. The printer is paused.

7. The printhead is over temperature.

8. FLASH memory is not programmed.

9. The printhead or motor has had a critical failure.

10. The printer is defragmenting memory.

• Press the Feed button to resume printing.

• Printing will stop until the printhead cools to an acceptable printing temperature. When it
does, the printer will automatically resume operation.

• Return the printer to an authorized reseller.

• Return the printer to an authorized reseller.

Caution • Do NOT turn off the printer power during defragmentation. Doing so can damage

the printer.

• Defragmentation is a normal operation of the printer – necessary to manage the memory
space for optimal use. The printer will defragment its memory both after a factory default
and when the printer detects that a defragment is required.

When the printer is in this condition, allow it to finish defragmenting. If this warning occurs
frequently, check the label formats. Formats that frequently and repeatedly write to and
erase from memory my cause the printer to defragment often. Using formats that avoid
frequent and repeated memory write/erase event will minimize the need for
defragmentation.

• If this warning condition does not go away, contact Technical Support. The printer
requires service.

P1039494-001 GC420d™ User Guide 8/15/2011

Print Quality Problems

No print on the label.

• The media may not be direct thermal media. See the test procedure Determining Thermal

Media Types on page 31.

• Is the media loaded correctly? Follow the instructions for Loading Roll Media on page 11
in the Getting Started section. For printing using transfer ribbon, see Printing a Test

(Printer Configuration) Label on page 15.

The printed image does not look right.

• The printhead is dirty. Clean the printhead.

• The printhead is under temperature.

• Adjust the print darkness and/or print speed.

Print Quality Problems

71

•Use the
Programming Guide.

•Use the
Guide.

• Manually adjust print darkness with the six-flash sequence of Feed Button Modes

on page 78.

• The Windows printer driver or application software may change these settings and
may require a change to optimize print quality.

• The media being used is incompatible with the printer. Be sure to use the recommended
media for your application, and always use Zebra-approved labels and tags.

• The printhead has worn out. The printhead is a consumable item and will wear out due to
friction between the media and printhead. Using unapproved media may shorten life or
damage your printhead. Replace the printhead.

• The platen may need cleaning or replacement. The platen (driver) roller maybe losing
traction due to:

• Foreign objects attached to its surface,

• The rubbery smooth surface has become polished and slippery, or

• There is damage to the normally smooth and flat print surface such as box knife cuts.

^PR (speed) and ~SD (darkness) commands referenced in the ZPL

D (darkness/density) and S (speed) commands in the EPL Programmer’s

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72

Print Quality Problems

There are long tracks of missing print (blank vertical lines) on
several labels.

The printing does not start at the top of the label or misprinting of
one to three labels.

• The printhead is dirty. Clean the printhead.

• The printhead elements are damaged.

• The media may not be threaded correctly. Follow the instructions for Loading Roll Media

on page 11 in the Getting Started section.

• The printer needs to be calibrated. Refer to the two-flash sequence of Feed Button Modes

on page 78 in this section.

• ZPL Label Formats - The correct media sensor may not be activated. Manual calibration
selects the media sensing method for the labels being used (refer to the
the ZPL Programming Guide).

^MN command in

• ZPL Label Formats - Verify that the Label Top (
application (consult the ZPL Programming Guide).

• EPL Label Formats - The correct media sensor may not be activated for label dispensing,
blackline or notch sensing, or for Gap/Web sensing. Manual calibration selects the media
sensing method for the labels being used (refer to the
Programmer’s Guide).

• EPL Label Formats - Verify that the Set Label Length (Q) command is correctly set for
your application (consult the EPL Programmer’s Guide).

^LT) command is correctly set for your

O and Q commands in the EPL

A ZPL label format was sent to, but not recognized by, the printer.

• Is the printer in pause mode? If so, press the Feed button.

• If the status LED is on or flashing, refer to What the Status Light is Telling You on page 68.

• Make sure the data cable is correctly installed.

• A communications problem has occurred. First, make sure that the correct
communications port on the computer is selected. Refer to Connecting your Printer to a

Computer on page 18 in the Getting Started section.

• Verify the correct Format and Control Prefix on the printer match what you are using in
your ZPL programmed label format. The default Format (COMMAND CHAR) is Caret
(^) character and the Control (CONTROL CHAR) is a Tilde (~) character. Verify the
characters with the Configuration Status label printout. Refer to the one-flash sequence of

Feed Button Modes on page 78 to print this label.

P1039494-001 GC420d™ User Guide 8/15/2011

Print Quality Problems

A EPL label format was sent to, but not recognized by, the printer.

• Is the printer in pause mode? If so, press the Feed button.

• If the printer has label dispensing enabled, the printer may be waiting for the label to be
removed. The liner/web must be properly threaded through the label dispenser mechanism
(peeler) to correctly operate in label dispense mode, refer to Label Dispenser Option

on page 42.

• If the status LED is on or flashing, refer to What the Status Light is Telling You on page 68.

• Make sure the data cable is correctly installed.

• A communications problem has occurred. First, make sure that the correct
communications port (USB) on the computer is selected. Refer to Connecting your

Printer to a Computer on page 18 in the Getting Started section.

73

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74

Manual Calibration

Manual Calibration

Manual calibration is recommended whenever you are using pre-printed media or if the printer
will not correctly auto calibrate.

1. Make sure media is loaded.

2. Turn on the printer power.

3. Press and hold the Feed button until the green status light flashes once, then twice and

then continuing until the flash groups reach the group of seven flashes. Release the Feed
button.

4. The printer will set the media sensor for the label backing being used. After it is done

making this adjustment, the roll will automatically feed until a label is positioned at the
printhead. A profile of the media sensor settings (similar to the example below) will print.
Upon completion, the printer will save the new settings in memory and the printer is ready
for normal operation.

5. Press the Feed button. One entire blank label will feed. If this does not happen, try

defaulting (refer to the four-flash sequence in “Feed Button Modes” later in this chapter)
and recalibrating the printer.

Note • Performing a manual calibration disables the auto calibration function. To return to

auto calibration, default the printer (refer to the four-flash sequence in Feed Button Modes

on page 78 in this section).

P1039494-001 GC420d™ User Guide 8/15/2011

Troubleshooting Tests

Printing a Configuration Label

To print out a listing of the printer’s current configuration, refer to the one-flash sequence in

Feed Button Modes on page 78 in this section. See Appendix: ZPL Configuration on page 91

to interpret the label.

Troubleshooting Tests

75

Recalibration

Recalibrate the printer if it starts to display unusual symptoms, such as skipping labels. Refer
to the two-flash sequence in Feed Button Modes on page 78 in this section.

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76

Resetting the Factory Default Values

Resetting the Factory Default Values

Sometimes, resetting the printer to the factory defaults may solve some problems. Refer to the
four-flash sequence in Feed Button Modes on page 78 in this section.

Communications Diagnostics

If there is a problem transferring data between the computer and printer, try putting the printer
in the communications diagnostics mode. The printer will print the ASCII characters and their
respective hexadecimal values (a sample is shown below) for any data received from the host
computer. To find out how,

There are multiple ways to enter hex data dump mode:

•The ~JD ZPL command

•The dump EPL command

• On power up with the Feed button pressed. Refer to the power off mode procedure in Feed

Button Modes on page 78 in this section.

The printer will print ‘Now in DUMP’ (see below) and advance to the top of the next label.

P1039494-001 GC420d™ User Guide 8/15/2011

Communications Diagnostics

The following example of a communications DUMP mode printed out. The printout displays
hexadecimal data 00h-FFh (0-255 decimal) with a unique character for each hexadecimal
value displayed above the hexadecimal data.

77

The blank lines between the lines of data are where serial port and Bluetooth data handling
errors get logged. The errors are:

•F = Frame Error

• P = Parity Error

•N = Noise Error

• O = Data Overrun Error

To exit the diagnostic mode and resume printing, turn off and then turn on the printer. An
alternate method for exiting the diagnostic mode is to press the Feed button as many times as it
takes to clear the printer’s command buffer and print ‘Out of DUMP’ on the label.

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78

Feed Button Modes

Feed Button Modes

With the printer power off, press and hold the Feed button while you turn on the power.

Flash Sequence Action

Amber - Red
Flashing

Amber

Green

Power Off Modes

Firmware Download Mode - The printer starts rapidly flashing red to denote entry into
the Firmware Download mode. Releasing the Feed button here will start initializing the
printer for download. The printer is ready to start downloading firmware when the status
light begins to slowly flash between red and green.

See Sending Files to the Printer on page 40 for more information on using the Firmware
(and File) Download utility available for use with this printer. Firmware updates for your
printer, if available, are posted on the Zebra on our web site at:

www.zebra.com

Normal Operations Mode - The printer continues into a normal printer initialization.
Releasing the Feed button here will allow the printer to start normally without firmware
download or operating in communications diagnostics mode.

Communications Diagnostic (Dump) Mode - Release the Feed button immediately after
the printer status light turns green. The printer will print ‘Now in DUMP’ at the top of the
label and then advance to the next label. After printing the first label, the printer will
automatically enter into diagnostic mode in which the printer prints out a literal
representation of all data subsequently received.

To exit the diagnostic mode and resume printing, turn off and then turn on the printer. An
alternate method for exiting the diagnostic mode is to press the Feed button as many times
as it takes to clear the printer’s command buffer and print ‘Out of DUMP’ on the label.

P1039494-001 GC420d™ User Guide 8/15/2011

Feed Button Modes

Power On Modes

With the printer power on and top cover closed, press and hold the Feed button for several seconds. The green status
LED will flash a number of times in sequence. The explanation at the right (Action) shows what happens when you
release the key after the start specific number of flashes and before the next flash sequence starts.

Flash Sequence Action

Configuration Status - Prints a detailed printer configuration status label. The label can be used

*

*
**

*
**
***

*
**
***
****

*
**
***

to verify printing, assist printer to computer communication configuration, maintenance,
troubleshooting, and help us with customer care communications.

Standard Auto Media Calibration - The printer detects and sets media type and media length,
and it adjusts the media sensors for optimal performance with the installed media (equivalent ZPL
command ~JC). The printer will feed one to four labels while calibrating.

Note: Users familiar with the Zebra EPL desktop printer use this Feed mode to replace power-up
AutoSensing calibration (equivalent EPL command XA).

Serial Port Configuration - Applies only to printers with serial interface ports.

To reset the serial port communication parameters, except for Flow Control. Press and release the
Feed button while the LED rapidly flashes amber and green.

For autobaud synchronization: Send the ^XA^XZ command sequence to the printer while the LED
rapidly flashes amber and green. When the printer and host are synchronized, the LED changes to
solid green. NOTE: No labels will print during autobaud synchronization.

Factory Defaults - Resets the printer to the factory default settings (equivalent to ZPL command
^JUN). See Appendix: ZPL Configuration on page 91 for a description of the primary

configuration settings and their associated ZPL commands. Some configuration settings are not
returned to their initial ‘out of box’ settings. Other settings are exclusively set, viewed and
controlled by programming are also reset. The printer then performs a standard media calibration
followed by .a memory defragmentation routine.

Once a network printer has entered the Factory Default mode, the status light will turn amber
for three (3) seconds. During that time you may do two things: Do nothing and the printer will
reset the factory defaults automatically as described above OR press and hold the feed button to
enter a factory default reset modes for printers with a network (Ethernet, Wi-Fi or Bluetooth)
printer option (equivalent ZPL command ^JUF). Releasing the button after the first flash resets
the network factory options only (equivalent ZPL command ^JUN). Releasing the button after
the second flash sequence (two flashes) will reset the printer defaults only. Releasing the button
after the third flash sequence (three flashes) will reset both printer and network settings
(equivalent ZPL commands ^JUN and ^JUF)

Print Width Adjustment - Prints a succession of boxes starting at the minimum print width and
ending in the printer’s maximum print width in 4mm increments. Press the Feed button once when
the printer has reached the desired maximum print width. Note that the printer driver and
applications can override this setting.

****
*****

79

*
**
***
****
*****

Print Darkness (Density) Adjustment - Prints a succession of bar code simulation patterns
starting at the minimum darkness (print density/heat) and ending in the printer’s maximum
darkness in increments of four (4) using the ZPL darkness setting range values. Press the Feed
button once the pattern is clear and legible. Do not continue to increase the darkness setting or
bar code line widths may become distorted reducing readability. Note that the printer driver and
applications can override this setting.

******

*
**
***
****
*****

Manual Media Calibration - The printer runs extensive tests to detect and set media type and
media length, and then it adjusts the media sensors for optimal performance with the installed
media (equivalent ZPL command ~JG). Manual calibration is recommended whenever you are
using pre-printed media, print on the liner or if the printer will not correctly auto calibrate. A
graphical profile of the media sensing will print. See Manual Calibration on page 74 for more
details and considerations.

******
*******

If the Feed button remains pressed after 7th flash sequence cycle finishes, the printer exits the
configuration mode when the Feed button is released.

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Notes • ___________________________________________________________________

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__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

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__________________________________________________________________________

__________________________________________________________________________

Feed Button Modes

P1039494-001 GC420d™ User Guide 8/15/2011

A

Appendix: Interface Wiring

This section provides printer interface connection information.

Contents

Universal Serial Bus (USB) Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Parallel Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Ethernet Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Serial Port Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

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82

1

2

3

4

Universal Serial Bus (USB) Interface

Universal Serial Bus (USB) Interface

The figure below displays the cable wiring required to use the printer’s USB interface.

The printer requires cable or cable packaging that bears the “Certified USB™” mark to
guarantee USB 2.0 compliance.

Pin Signal

1Vbus - N/C

2D-

3D+

4Ground

Shell Shield / Drain Wire

For printer supported operating systems and drivers, see the software and documentation CD
or visit the Zebra Web site at:

http://www.zebra.com

For information on the USB interface, go to the USB web site at:

http://www.usb.org

P1039494-001 GC420d™ User Guide 8/15/2011

Parallel Interface

PRINTER

DB-25

Pin No.

Centronics

Pin No.

DB-25 to Centronics

(Cable)

HOST

STROBE~

DATA 0
DATA 1
DATA 2
DATA 3
DATA 4
DATA 5
DATA 6
DATA 7

ACK~

BUSY

PAPER ERR.

SELECT

AUTOFD~

ERROR~

N/A
N/A

N/A
SIG. GND
SIG. GND
SIG. GND
SIG. GND
SIG. GND
SIG. GND
SIG. GND

STROBE~

DATA 0
DATA 1
DATA 2
DATA 3
DATA 4
DATA 5
DATA 6
DATA 7

ACK~

BUSY

PAPER ERR.

SELECT

AUTOFD~

n/c

SIG. GND

CHAS GND

+5V
SIG. GND
SIG. GND
SIG. GND
SIG. GND
SIG. GND
SIG. GND
SIG. GND

n/c

ERROR~

SIG. GND
SIG. GND
SIG. GND
SIG. GND
SIG. GND

SIG. GND

n/c
n/c

SELECTIN~

1
2
3
4
5
6
7
8

9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

1
2
3
4
5
6
7
8

9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36

The printer’s parallel interface uses the IEEE 1284-A to 1284-B parallel interface cables. the
host connector has a DB-25 pin male connector. The printer connector is a Centronics style
connector.

Parallel Interface

83

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84

4
3
2
1

5
6
7
8

Ethernet Interface

Ethernet Interface

This interface requires a UTP RJ45 Ethernet cable rated CAT-5 or better.

The table below provides the cable’s pinout assignments.

Signal Pin Pin Signal
Tx+11Tx+
Tx-22Tx­Rx+33Rx+
—44—
—55—
Rx-66Rx­—77—
—88—

P1039494-001 GC420d™ User Guide 8/15/2011

Serial Port Interface

DB-9P

Connector

to Printer

DB-9P

Connector

to Printer

DB-25S
Connector
to DCE Device

DB-9S
Connector
to DCE Device

Pin Description

1 +5 V @ 0.75 A fused
2 TXD (transmit data) output from the printer
3 RXD (receive data) input to the printer
4 DSR (data set ready) input to the printer
5 Chassis ground
6 DTR (data terminal ready) output from the printer -- controls

7 CTS (clear to send) - Not used by the printer
8 RTS (request to send) output from the printer -- always in the

9 Not used

The maximum current available through the serial and/or parallel port is not to
exceed a total of 0.75 Amps.

When XON/XOFF handshaking is selected, data flow is controlled by the ASCII
control codes DC1 (XON) and DC3 (XOFF). The DTR control lead will have no
effect.

Serial Port Interface

85

when the host may send data

ACTIVE condition when the printer is turned on

Interconnecting to DCE Devices — When the printer is connected via its RS-232
interface to data communication equipment (DCE) such as a modem, a Null
Modem RS-232 (straight-through) interface cable must be used. The figure below
shows the connections required for this cable.

Connecting to the KDU (Keyboard Display Unit) — The KDU was designed for
DCE printer connections (and does not require an adapter to communicate).

Connecting the Printer to a DCE Device

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Notes • ___________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

Serial Port Interface

P1039494-001 GC420d™ User Guide 8/15/2011

Appendix: Dimensions

This section provides external printer dimensions.

B

Contents

External GK Printer Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Label Dispenser Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Cutter Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

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88

All dimensions are

in inches

External GK Printer Dimensions

External GK Printer Dimensions

P1039494-001 GC420d™ User Guide 8/15/2011