Canon imageCLASS X LBP1238 II Service Manual page 145

● Gradation 17 Pattern (TYPE = 4)
Check item
Gradation Check that gradation in density is made appropriately.
Fogging Check that no fogging appears in the blank area.
Black line Check that no black line appears on the image.
White line Check that no white line appears on the image.
Uneven Density Check that there is no density difference between the front and
rear sides.
● Thin Horizontal Line Pattern (TYPE = 5)
Checking method
135
Assumed cause
Failure of Photosensitive Drum
Failure of laser exposure system
Failure of developing system
Failure of Photosensitive Drum
Failure of laser exposure system
Failure of developing system
Failure of developing system
Failure of cleaning (drum)
Failure of Transfer Roller
Soiling on the laser light path
Failure of developing system
Failure of Photosensitive Drum
Failure of developing system
Failure of Transfer Roller
7. Troubleshooting