Image Defects - Canon LBP-1210 Service Manual

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.
• II-1 Light:
• II-2 Dark:
• II-3 Completely Blank:
• II-4 All Black:
• II-5 Dots in Vertical Lines :
• II-6 Dirt on Back of Paper:
• II-7 Vertical Lines:
• II-8 Black Horizontal Lines:
• II-9 Dirt:
• II-10 Blank Spots:
• II-11 White Vertical Lines:
• II-12 White Horizontal Lines:
• II-13 Poor Fixing:
• II-14 Image Distortion:
• II-15 Faulty registration:
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
Table 4-2-1
Output very light image
Output very dark image
Output no image
Output all black paper
Output white dots on the paper
Output dirt on the back of the paper
Output vertical lines on the paper
Output horizontal lines on the paper
Output dirt on surface of the paper
Output image with blank spots
Output white vertical lines on the paper
Output white horizontal lines on the paper
Output the image with poorly fixed toner
Output distorted image
Gap between the leading edges of the paper and the image
CHAPTER 4
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