Oki Microline 421, ML420, ML421, ML420n, ML421n Specification Sheet

It’s designed for commanding performance in
demanding environments.

The OKI®MICROLINE®420 9-pin printer and its
wide-carriage counterpart ML421 are a quantum leap
forward in Impact printer performance.

Engineered for dedicated forms printing in the most
demanding point-of-sale, automation and utility
environments, ML420/421 printers are right at home
in applications such as retail sales counters, medical
facilities, automotive rental and repair shops, airline
boarding gates, financial departments and manufac­turing sites. Their print speed and versatile paper
handling make them ideal for the office, too.

Performance is built in. The ML420/421 sport

features that give them a strong edge over their
predecessors as well as the competition:

• 3-piece top cover provides easy access and

unsurpassed break resistance

• An internal cooling fan provides continuous airflow

for the printhead—maximizing throughput
productivity for long, unattended print jobs

• Additional feed rollers provide precise forms

handling and printed-character placement accuracy

Highlights:

Rated at 20,000 hours MTBF
3-Year standard warranty
Print speeds up to 570 cps

1

Integrated USB and IEEE Parallel connectivity
standard

Optional OkiLAN

®

6120i 10/100 Base-T Ethernet

®

internal print server
Crisp, clear printing on 6-part forms
Expandable head gap – accommodates multi-

part forms and cut-sheet stock including labels
and stiff index stock

128 KB receive buffer/memory

7.5 million-character ribbon life
200-million character printhead life
Small footprint – ideal for retail countertops
Uses the same accessories as

ML320/321 Turbo Series

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SuperSpeed Draft Mode.

Reliable,

fast

and

easy to use.

Exceptional paper-handling versatility. The

ML420/421 have a zero-tear feature that accurately
positions continuous forms for a clean tear at the
perforation, which eliminates wasted stock. You also
get perfect results with single sheets, index stock,
labels and envelopes, too. All without jams or smears.

Value that goes the distance. The OKI ML420/421

deliver the kind of productivity usually reserved for
printers many times the price—starting with a super­fast print speed of 570 characters-per-second (in
SuperSpeed Draft mode).

Then there’s the rugged printhead—with its
200-million character life, powerful samarium cobalt
magnets and stored-energy pins— delivering precise,
sharp characters all the way through to the last
page of a 6-part form. And the patented OKI
closed-loop feedback system that assures character
placement accuracy.

The OKI ML420/421: Just turn ‘em on and
turn ‘em loose.

This rugged dedicated forms printer
is backed by a 3-Year standard warranty.

Narrow carriage
MICROLINE 420

OKI®MICROLINE®420/421

9-Pin Impact Printers

Printed in the USA. MS11326/0404pdf

Wide-carriage MICROLINE 421

Built to last, inside and out. Field-proven reliability

is just one reason OKI

®

MICROLINE®impact printers

are the most widely-used in North America.

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The performance-optimized power supply of the
ML420/421 has been enlarged to easily handle
harsh printing conditions—and its energy
management capabilities match power expenditures
to print-job size, maximizing the life of the 9-pin
printhead and other components. A long-lasting
rack-and-pinion drive system ensures print quality
longer than belt or cable systems. And the
ergonomically-designed, impact-resistant chassis
protects the ML420/421 from damage, even in the
toughest working environments.

Performance that’s user-friendly. Controls are

conveniently placed on the front panel for fast
access. The automatic loading of continuous and cut
stock makes every print job easier, and the design of
the internal sheet separator enables easy loading of
tractor-fed paper into the rear push tractor.

OKI has a reputation for quality and reliability no
competing printer can claim—and backs it with
3 years of warranty coverage

2

and a network of
authorized OKI Dealer Service Centers and Service
Depots.

The reliable, affordable ML420/421 can
work wonders in virtually any forms-handling
application.

Specifications

Technology, Speed and Print Characteristics

• Printhead: 9-Pin SIDM

• Graphics Resolution: 240 (H) x 216 (V) dpi maximum

• Feed Rate: 4.5 ips (11.4 cm/sec.)

• Print Speed and Character Matrix:

Mode NLQ Utility HSD SSD

(10 cpi) (10 cpi) (10 cpi) (12 cpi)

Speed (in cps) 95 380 510 570

Emulation, Interface and Memory

• Emulation: Epson®FX, IBM®ProPrinter®, OKI MICROLINE

• Interface: Standard – IEEE Parallel and USB;

Optional – RS-232C Serial and Ethernet

®

via OkiLAN®6120 i
10/100 Base-T Internal Print Server (no AC power adapter
required); Twin-ax/Co-ax (Also available through 3rd Party)

• Memory: 128K

Compatibility

• Operating Systems: Windows®XP, 2000, 98/95,

3.x and NT

®

4.0; MS-DOS

®

Paper Handling

• Paper Input: Single-part, Multi-part, Continuous forms,

Cut sheet, Index stock, Envelopes, Labels

• Number of Copies: 6

• Thickness: 0.017" (0.43 mm) maximum

• Paper Feeding: Rear Push and Friction Feed

• Options: Bottom Push Tractor, Top Pull Tractor,

Cut Sheet Feeder, Roll Paper Stand

Warranty and Reliability

• Limited Warranty: 3-Year parts and labor, 2-Year printhead

• MTBF: 20,000 hours (25% duty cycle/ 35% page density)

• Reliability:

ML420 – 24,000 pg./mo. duty cycle
ML421 – 17,000 pg./mo. duty cycle

• Printhead Life: 200 million characters

•Ribbon Life: 7.5 million characters

Environmental

• Size (WxDxH):

ML420 – 15.7" x 13.6" x 6.0" (39.8 cm x 34.5 cm x 15.2 cm);
ML421 – 21.7" x 13.6" x 6.0" (55.1 cm x 34.5 cm x 15.2 cm)

• Net Weight:

ML420 – 16.4 lb. (7.43 kg); ML421 – 21.2 lb. (9.6 kg)

• Acoustic Noise: 56 dBA

• Power Requirements: 120V Model: 120 VAC +6%, -15%;

230V Model: 230 VAC +15%, -14%

For more information on OKI Impact Printers and sup-

plies, including OKIcare®Extended Service Programs:
1-800-OKI-DATA (800-654-3282).

1

Q4 2003 IDC Quarterly Tracker and Evans Research.

2

3-year standard warranty parts and labor/2-year printhead.

3

Available in the U.S. and Canada only.

All specifications subject to change without notice.
© 2004 Oki Data Americas, Inc. OKI Reg.T.M., M.D., M.R.,MICROLINE,

OkiLAN, OKIcare Reg. T.M., Oki Electric Industry Co., Ltd. 7-Day/24-Hour
logo T.M., Oki Data Americas, Inc. Epson Reg.T.M., Seiko Epson Corp. IBM,
ProPrinter Reg. T.M., International Business Machines, Inc. Windows,
Windows NT,MS-DOS Reg.T.M., Microsoft Corp. Ethernet Reg.T.M., SCO.
Energy Star Reg. T.M., U.S. EPA. USB-Logo T.M. Universal Serial Bus
Implementers Forum, Inc.

OKI®MICROLINE®420/421

9-Pin Impact Printers

Ordering Information

Description Part Numbers

MICROLINE 420/Parallel/120V 62418701
MICROLINE 420/Parallel/120V/Black 91909701
MICROLINE 420/Parallel/230V 62418702
MICROLINE 421/Parallel/120V 62418801
MICROLINE 421/Parallel/230V 62418802

Accessories

Top-Mount Pull Tractor Kit with acoustic cover:

ML420 70030501
ML421 70030601

Bottom Push Tractor Kit:

ML420 70030701

ML421 70030801
Cut Sheet Feeder 70030101
Roll Paper Stand (ML420 only) 70023301
RS-232C Serial Interface (19.2K baud max.) 70012801
OkiLAN

®

6120i 10/100 Base-T Ethernet

Internal Print Server 70046501
OkiLAN

®

6020e 10/100 Base-T Ethernet

External Print Server 70036001
OkiLAN 6010e 10 Base-T Ethernet

External Print Server 70034401
Self-inking Ribbon Cartridge 42377801
Co-ax Adapter 70047201

Twin-ax/Co-ax (Also available through Third Party.

Call 1-800-OKI-DATA.)

OKIcare®Overnight Exchange Warranty
Extensions

3

U.S. Canada

OKI ML400 Series 1-Yr.Warranty Ext. 58264901 58263111
OKI ML400 Series 2-Yr.Warranty Ext. 58264902 58263112

OKIcare®Depot Warranty Extensions

3

U.S. Canada

OKI ML400 Series 1-Yr.Warranty Ext. 58264701 58265511
OKI ML400 Series 2-Yr.Warranty Ext. 58264702 58265512
Upgrade to 3-Yr. Overnight Exchange 58264801 58264811

To contact Oki Data Americas, Inc.
In USA: 2000 Bishops Gate Blvd.

Mount Laurel, NJ 08054-4620
Tel: 800.OKI.DATA (800.654.3282)
Fax: [phone]

In Canada: 2735 Matheson Blvd. East
Mississauga, Ontario L4W 4M8
Tel: [phone]
Fax: [phone]

In Latin America and Mexico:

2000 Bishops Gate Blvd.
Mount Laurel, NJ 08054-4620
Tel: [phone]
Fax: [phone]

www.okidata.com 800.OKI.DATA