Dark/Black Image; Uneven Density; Background - Ricoh BP20 Service Manual

4.6.7 DARK/BLACK IMAGE

Description: Printed image is dark.
Cause
1. No charge voltage from the engine board.
2. Charge voltage fault due to bad contact
between toner cartridge and cartridge set.
3. VD0 signal from main PBA is low.

4.6.8 UNEVEN DENSITY

Description: Side-to-side print density is uneven.
Cause
1. Pressure force on the left and right
springs of the transfer roller is not even,
springs are damaged, transfer roller is not
correctly installed, transfer roller bushings
or holders are damaged.
2. Toner cartridge has reached end of life.
3. Toner inside the cartridge is not level due
to damaged blade or low toner.

4.6.9 BACKGROUND

Description: A faint, "background" type of imaging defect is visible throughout the
output print.
Cause
1. The machine has not printed large
quantities of low coverage pages, or the
machine has not been used for an
extended period.
2. A recycled toner cartridge is being used.
3. The toner cartridge has reached end of
life.
4. The up/down movement of the transfer
roller is not smooth.
5. HVPS is not functioning normally.
SM
Solution
1. Check the connector that connects the
HVPS and the engine board.
2. Clean the high voltage charge terminals.
Replace the HVPS if the problem
persists.
3. Replace the LSU or main PBA.
Solution
1. Replace both the left and right bushings
and spring assemblies.
2. Replace the toner cartridge.
3. Gently shake the toner cartridge side to
side 5-6 times and try to print again.
Replace the toner cartridge if the problem
persists.
Solution
1. The toner cartridge is designed to print
3,000 sheets with 5% coverage.
Background can appear if the machine
prints more than 3,600 pages with only
2% coverage.
2. Machine operation is not guaranteed
when using recycled toner cartridges.
Gently shake the toner cartridge side to
side 5-6 times and try to print again.
Replace the toner cartridge if the problem
persists.
3. Replace the toner cartridge.
4. Clean the transfer roller bushings.
5. Clean the high voltage charge terminals.
Replace the HVPS if the problem
persists.
4-13
PRINTOUT PROBLEMS
G144/G145