HP LaserJet 1160, 1320, Service Manual

Size:
8.47 Mb
Download

Changing the printer separation pad

Normal use with good media causes wear. The use of poor media might require more frequent replacement of the separation pad. If the printer regularly pulls multiple sheets of media at a time, you might need to change the separation pad.

1. Remove the main input tray (tray 2).

2. Locate the separation pad.

ENWW

Changing the printer separation pad 59

3. Remove the screws.

60 Chapter 4 Maintenance

ENWW

 

4. Remove the separation pad.

NOTE

Before you proceed to step 4, examine the position of the separation pad in the tray.

5. Insert the new separation pad.

ENWW

Changing the printer separation pad 61

6. Replace the screws.

62 Chapter 4 Maintenance

ENWW

Cleaning the printer separation pad

If you want to clean the separation pad rather than replace it, follow the instructions below.

1.Remove the separation pad as described in steps 1 through 4 of Changing the printer separation pad.

2.Dab a lint-freecloth in water, and scrub the separation pad.

3.Using a dry, lint-freecloth, wipe the pickup roller to remove loosened dirt.

4.Allow the separation pad to dry completely before you reinstall it in the printer (see steps 5 and 6 of Changing the printer separation pad).

ENWW

Cleaning the printer separation pad 63

64 Chapter 4 Maintenance

ENWW

5

Theory of operation

Chapter contents

 

Chapter contents......................................................................................................................

65

Introduction...............................................................................................................................

66

Internal components.................................................................................................................

67

Timing.......................................................................................................................................

68

Engine control system..............................................................................................................

70

Laser/scanner system..............................................................................................................

72

Pickup/feed/delivery system....................................................................................................

73

Image-formationsystem...........................................................................................................

75

ENWW

Chapter contents 65

Introduction

This chapter presents an overview of the relationships between major components in the printer, and includes a detailed discussion of the image-formationsystem. The following systems are discussed:

Engine control system

Laser/scanner system

Pickup/feed/delivery system

Image-formationsystem

Figure 5-1. Block diagram illustrates the relationships among the four systems.

Figure 5-1.

Block diagram

66 Chapter 5 Theory of operation

ENWW

Internal components

Figure 5-2. Cross-section of printer highlights the major internal components.

Figure 5-2.

Cross-sectionof printer

 

1

Top output bin delivery roller

 

2

Fuser film

 

3

Laser/scanner

 

4

Primary charging roller

 

5

Developing cylinder

 

6

Print cartridge

 

7

Feed roller

 

8

Separation pad

 

9

Pickup roller

 

10

Registration roller

 

11

Duplexer pickup roller

 

12

Registration shutter

 

13

Transfer roller

 

14

Photosensitive drum

 

15

Duplexer feed roller

 

16

Pressure roller

 

17

Rear output bin delivery roller

ENWW

Internal components 67

Timing

Sequence of operation

Operation sequences are controlled by the microprocessor on the dc controller. Table 5-1. Sequence of operation describes engine operations for each period of a print operation.

Table 5-1.Sequence of operation

Name

Timing

WAIT

From power-onuntil the end of the main

 

motor initial drive

STBY

From the end of the WAIT or LSTR

(standby)

period until either a print command is

 

sent from the formatter or the power is

 

turned off.

Purpose

Detects presence of a print cartridge. Clears potential from the drum surface and cleans the transfer roller.

See Table 5-2. Power-on sequence for a complete description of the WAIT (poweron) period. Also see General timing chart for detailed information about printer timing.

Prepares the printer to receive print commands

INTR (initial

From the time of the print command until

rotation)

the pickup solenoid is turned on.

PRINT

From the end of the INTR period until the

 

primary high-voltageis turned off.

LSTR (last

From the end of the PRINT period (when

rotation)

high-voltageis turned off) until the main

 

motor stops rotating.

Prepares the photosensitive drum for printing.

Forms the image on the photosensitive drum and transfers the toner image to the media.

Delivers the last page of a print job.

After LSTR, the printer either returns to STBY or, if another print command was sent from the formatter, enters INTR.

Power-onsequence

Table 5-2.Power-onsequence

Step

Action

1

Power-on

2

CPU initialization

3

Video interface communication start

4

Check sensors for residual media

5

Main motor initial drive

6

Fuser heater initial drive. The fuser heater reaches a surface temperature

 

of 100 degrees C.

7

Laser/scanner motor initial drive

68 Chapter 5 Theory of operation

ENWW