Specifications

Troubleshooting Print Quality Problems - 1

Image Quality Problems

It can be easily determined whether an image quality problem is being caused by the print engine or by the

I/O controller board by producing a service test page. The service test page can be generated by jumper-

ing the two pins of connector J101 on the I/O controller board.

If the test page is normal, but the regular prints have an image quality problem, the problem is probably

with the I/O controller board. If the test print has also the image quality problem, the problem is probably

in the print engine.

When troubleshooting an image problem, produce a test print using letter size or A4 paper, exactly iden-

tify the symptom, and isolate the problem by referencing the accompanying troubleshooting tables.

If the tables do not lead you to a solution to the problem, examine each part listed in the initial analysis of

the table corresponding to the problem. The fault is probably among those parts. Replace the part or parts

that in your judgment will most likely resolve the problem.

Roller Diameters

For a listing of the diameters of the rollers in the LaserWriter 12/640 PS, see page 13 in the Principles of

Operation chapter. Knowing these diameters can assist in troubleshooting repetitive horizontal print

defects.

List of Troubleshooting Tables

The troubleshooting tables cover the following typical fourteen image quality problems:

Table P-1 Light Prints

Table P-2 Blank Prints

Table P-3 Black Prints

Table P-4 Vertical Band Deletions

Table P-5 Horizontal Band Deletions

Table P-6 Vertical Streaks

Table P-7 Horizontal Streaks

Table P-8 Spot Deletions

Table P-9 Spots

Table P-10 Residual Image

Table P-11 Background

Table P-12 Skewed Image

Table P-13 Damaged Prints

Table P-14 Unfused Image

Table P-15 No PhotoGrade

Table P-16 No Duplex Printing

Table P-17 Duplex Page Upside-Down

Table P-18 No Multipurpose Tray Printing

Note

: Vertical refers to the direction of paper travel. Horizontal refers to the direction perpendicular to

the direction of paper travel.