Xerox 3150 - Phaser B/W Laser Printer, Service Manual

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Troubleshooting
7-4
7.1.7 Uneven Density
7.1.8 Background Contamination
Example Possible Cause Sequence of Repair Actions
Print density is uneven from left to right.
1. The toner level is not even on the
toner cartridge roller due to a
damaged blade or low toner.
2. The life of the toner cartridge has
expired.
3. The pressure force on the left and
right springs of the transfer roller
are not even or the springs are
damaged.
4. The transfer roller is improperly
installed.
5. The transfer roller bearings or
holders are damaged.
6. Laser window is dirty.
a. Remove the toner cartridge and gently
shake it to loosen toner.
b. Replace the toner cartridge and retest.
c. Replace the left and right bushings and
spring assemblies.
d. Clean the laser window.
Example Possible Cause Sequence of Repair Actions
Light or dark background contamination appears all over the paper.
1. Using unsupported media.
2. Printing large quantities of low
coverage (2%) pages or not using
the printer for a long period of time.
3. The toner cartridge life has expired.
4. The transfer rollers up/down
movement is off.
5. There is a problem with the HVPS.
a. Use only approved media.
b. The toner cartridge is designed to print
5,000 sheets at 5% coverage. If 2% is
consistently used, background
contamination can occur.
c. Replace the toner cartridge.
d. Clean the transfer roller bushings.
e. Clean the high voltage terminals.
f. Replace the HVPS.
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