Rap 7.8 Image Quality Problems; Image Quality Defect Definitions, Causes And Solutions - Xerox DocuPrint P8e Service Manual

RAP 7.8 Image Quality Problems

This section contains image quality repair procedures to assist in correcting image quality defects. These
procedures provide definitions, causes and solutions.
Throughout these procedures, the term "vertical" refers to the process direction (the direction paper
travels through the printer); the term "horizontal" refers to the scanning direction (the direction the laser
beam scans across the page).

7.0.1 Image Quality Defect Definitions, Causes and Solutions

Defect Definitions
NON-UNIFORM IMAGE
QUALITY: The line darkness and
solid area density image vary
across the print.
BLACK PRINTS: the print is
completely covered with toner
and has no visible image.
HORIZONTAL DELETIONS:
There are areas of the image that
are extremely light or missing
entirely. These missing areas
form wide bands that run
horizontally across the page in
the direction of scanning.
Repair Analysis Procedures (RAP)
Possible Causes
1. Print Cartridge.
2. Print Cartridge ground.
3. Unstable high voltage output.
4. BTR contamination.
5. LSU Laser window
contamination.
1. Controller PWB.
2. Incorrect charge voltage.
3. Print Cartridge.
4. Engine Controller PWB.
5. Laser on all the time.
1. Controller PWB.
2. Print Cartridge grounding
problem.
3. Print Cartridge.
4. Transfer Roller.
5. Laser Assembly
6. Engine Controller PWB.
7. Fuser Assembly.
7/98
7-12
Solutions
1. Inspect drum for deterioration or contamination.
If defective, replace the Print Cartridge.
2. Verify Print Cartridge ground. Check continuity
between cartridge contact and the Controller
PWB metal cover. Ensure that the drum contact
is clean and undamaged.
3. Verify that all high voltage outputs are to
specification (refer to section 5, DCU operation).
4. Inspect Transfer Roller spring tension and
bearings. Remove the Transfer Roller and clean
(dust off). Replace Transfer Roller if necessary
(PL 7).
5. Remove the LSU (Laser) Assembly, clean or
replace as necessary (PL 6).
1. Using the DCU, print a DCU test print. If the test
print is OK, replace the Controller PWB. If test
print is black, continue.
2. Verify charge voltage output. Charge voltage
+/
equals - 1.3 KVDC - 100 VDC. If not replace
the HVPS PWB.
3. Replace Print Cartridge (PL 1).
4. Replace Engine Controller PWB (PL 10).
5. Replace LSU (LASER) Assembly (PL 6).
1. Using the DCU, print a DCU test print. If the test
print is OK, replace the Controller PWB (PL 10).
2. Verify Print Cartridge ground. Check continuity
between cartridge contact and the Controller
PWB metal cover. Ensure that the drum contact
is clean and undamaged.
3. If deletion repeats every:
94.3 mm (3.8in) - Drum defect
37.7 mm (1.5in) - Charge Roll
40.0 mm (1.2in) - Supply Roll
46.1 mm (1.8in) - Developer Roll
Replace the Print Cartridge (PL 1).
4. If deletion repeats every 47.1 mm (1.9 in.),
replace the Transfer Roller (PL 7).
5. Replace Laser Assembly (PL 6).
6. Replace Engine Controller PWB (PL 10).
7. If deletion repeats every 56.1 mm (2.2 in) Heat
Roll or 56.2 mm (2.2in) Pressure Roll, replace
the Fuser Assembly (PL 8)
Xerox DocuPrint P8e Service Manual