Service manual

DEVELOPING UNIT
2-G-3
2 UNIT EXPLANATION
[5] Toner Density Control
The toner density is controlled directly by PRCB
(printer control board) by controlling M11 (toner
supply 1). When the front right or left door of this
machine opens or closes, MS1 (interlock 1) or
MS2 (interlock 2) operates to interrupt the DC
power supply to the motor, stopping the M11.
1. Operation
a. Toner density detection
Concerning the toner density, the reference
patch density is detected by a patch detection
method. This method outputs the corresponding
analog voltage signal to the PRCB.
The PRCB compares the detected voltage with
the reference value to determine whether toner
must be added.
b. Toner supply operation
Upon read of the patch, M11 is turned ON to sup-
ply toner. The time needed to add toner depends
on the paper size.
2. Signals
a. Output signals
(1) M11 DRIVE A, A
(PRCB to M11)
M11 A-phase drive signal.
(2) M11 DRIVE B, B
(PRCB to M11)
M11 B-phase drive signal.
PRCB
M11
24VDC
24VDC
M11 DRIVE A
M11 DRIVE A
M11 DRIVE B
M11 DRIVE B
DCPS2
24VDC
PGND
MS2 MS1
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