Canon LASER SHOT LBP-1210, Service Manual

Page: 169 / 202

II. IMAGE DEFECTS
Perform troubleshooting according to the malfunction diagnosis flowchart (Figure 4-1-1). If an
“image defect” is found, the defective part must be located and rectified by the following proce-
dures.
Table 4-2-1
• II-1 Light: Output very light image
• II-2 Dark: Output very dark image
• II-3 Completely Blank: Output no image
• II-4 All Black: Output all black paper
• II-5 Dots in Vertical Lines : Output white dots on the paper
• II-6 Dirt on Back of Paper: Output dirt on the back of the paper
• II-7 Vertical Lines: Output vertical lines on the paper
• II-8 Black Horizontal Lines: Output horizontal lines on the paper
• II-9 Dirt: Output dirt on surface of the paper
• II-10 Blank Spots: Output image with blank spots
• II-11 White Vertical Lines: Output white vertical lines on the paper
• II-12 White Horizontal Lines: Output white horizontal lines on the paper
• II-13 Poor Fixing: Output the image with poorly fixed toner
• II-14 Image Distortion: Output distorted image
• II-15 Faulty registration: Gap between the leading edges of the paper and the image
II-1. Light
<Possible causes>
1) The image density is improperly adjusted.
Action: Adjust the image density by operating the external device.
2) Open the cartridge cover while printing and remove the EP-xx cartridge. Open the drum pro-
tective shield of the cartridge and check the toner image on the photosensitive drum surface.
If the toner image has not been transferred to the paper properly, go to step 3). If the toner
image on the drum is faint, go to step 7).
Do not open the drum protective shield for more than 10 seconds.
3) The transfer charging roller is deformed or deteriorated.
Action: Replace the transfer charging roller.
4) Poor contact in the transfer charging roller contact on the engine controller PCB and the
transfer charging roller shaft contact
Action: Clean the contacts if dirty. If the problem still remains after cleaning, or parts are
deformed or damaged, replace any defective parts.
5) Defective engine controller PCB
Action: Replace the engine controller PCB.
6) Defective interfece controller PCB
Action: Replace the interfece controller PCB.
7) Defective laser/scanner unit
CHAPTER 4
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