Doctor Roller Gap Adjustment - Ricoh DD 4450 Service Manual

4.10.8 DOCTOR ROLLER GAP ADJUSTMENT

Controls ink thickness around the ink roller.
Standard: 0.07 mm gauge passes, 0.09 mm gauge does not.
Tools: Thickness gauge
Normally, the doctor roller gap is not adjusted or changed. It tends to be difficult to

change in the field. If the gap is too narrow, an uneven image may appear on the prints. If
it is too wide, too much ink will be applied to the drum screens, resulting in ink leakage
from the drum.
Ink roller unit ( p.4-65 "Ink Roller Unit, Ink Roller One-Way Clutch")

1. Make sure that a 0.07 mm gap gauge goes through the gap [A] between the ink and doctor
rollers, and that a 0.09 mm gap gauge does not.
The gap should be checked at both ends of the doctor roller. Insert a gap gauge at

each end of the roller. The gap tends to be larger for the center.
While the gap gauge is inserted, hold the doctor and ink rollers with your fingers in

order to stop the rollers from rotating.
While the gap gauge is inserted, hold the end of the gap gauge

2. If the gap is out of the standard, loosen the screw [B] and adjust the gap by turning the cam
bushing [C] for the front and for the rear.
Make sure to repeat the adjustment for both ends of the rollers.

SM 4-67
Drum
C279