Ricoh FT4460, Service Manual, Page: 361 / 413

28 February 1989
1.18 TONER DENSITY TOO LOW
- Phenomena -
Toner density is too low.
(1) Density of the solid black areas is too low.
(2) Solid areas feel rough to the touch.
(3) Carrier is on the copy.
(4) Light spots appear on solid black copies.
- Possible Causes -
1.
2 .
Vsg is low.
When Vsg lower than 2.5V is detected five times in succession, the CPU
changes the toner supply to fixed supply mode (black) and the service
call indicator starts blinking.
Charge corona current is too high.
If the output of the ID sensor grid is increased, Vsp and the toner density
decrease.
3. ID sensor bias voltage of is too low.
4.
5.
Exposure lamp voltage is too low.
Toner supply clutch is defective.
Too many solid (dense) copies are being made.
The amount of toner supplied is inadequate for the amount of toner that
is required.
- Actions -
1. Check the following items by making a copy of the SP Mode Data Sheet
in SP Mode No.1.
No.31 Black Toner Supply Amount (ID sensor mode)
No.32 Black Toner Supply Amount (Fixed mode)
No.33 Black Toner ID Sensor Bias Adjustment
No.70 Color Toner Supply Amount (Fixed mode)
No.75 Color Toner Sensor Bias Adjustment
2. Check Vsg in SP Mode No.54
Set Vsg to +4 ± 0.2V by turning VR102 on the system control board.
If Vsg cannot be adjusted higher than 2.5V, check for a dirty or defective
ID sensor
12-24