M3 (Developing Motor) Control; Developing Bias Control - Konica Minolta 7020 Service Manual

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DEVELOPING UNIT
[3]

M3 (Developing Motor) Control

24VDC
24VDC
PGND
PGND
SGND
5VDC
DCPS
M3 (developing motor) is controlled by the PRDB (printer
drive board).
1. Operation
M3 runs on 24V DC power, and drives the developing
sleeve. M1 drives the agitator wheel and agitator
screws. (For information about M1, refer to "M1 (Main
motor) control.") M3 includes an internal speed sen-
sor, and utilizes PLL control to maintain a constant
speed, using a reference clock signal output by
PRDB.
M3 goes ON and OFF in sync with M1.
2. Signals
a. Input signal
(1) M3 LD (M3 −> PRDB)
M3 status detect signal.
Goes [L] when M3 rotation reaches the rated speed.
[H]: Stopped, or rotating at other than rated speed.
[L]: Rotating at rated speed. (PLL: stable)
b. Output signals
(1) M3 CONT (PRDB −> M3)
M3 drive control signal.
[L]: M3 ON
[H]: M3 OFF
(2) M3 CLK (PRDB −> M3)
Reference clock for M3 rotation control.
24VDC
24VDC
PGND
PGND
SGND
M3
M3 LD
M3 CLK
M3 CONT
SGND
5VDC
PRDB
2-G-2
[4]

Developing Bias Control

1
24VDC
24VDC
PGND
PGND
SGND
5VDC
24VDC
PGND
DCPS
Developing bias is controlled by the PRDB (printer drive
board) and the HV (high voltage unit).
1. Operation
Application of developing bias to the developing
sleeve starts a predetermined time interval after M3
(developing motor) comes ON, and ends a
predetermined time interval after charging goes OFF.
2. Signals
a. Output signals
(1) B CONT (PRDB −> HV)
Developing bias ON/OFF control signal.
[L] sets developing bias ON and outputs high
voltage.
(2) B SHIFT (PRDB −> HV)
Developing bias level control signal.
Analog signal from PRDB; controls the developing
bias output level.
B SHIFT output range
Bias-Voltage output range
24VDC
24VDC
PGND
PGND
SGND
M3
M3 LD
M3 CW/CCW
M3 CLK
M3 CONT
SGND
5VDC
SGND
PS1 PS1
5VDC
B CONT
BIAS
B SHIFT
PRDB
HV
2 to 8V
–350 to –830V