M15 (Polygon) Control - Konica Minolta 7155 Service Manual

WRITE UNIT
*2 Light source
Conventionally, two parallel beams were gener-
ated from two laser beams. The laser diode
adopted for this machine can generate two
beams using a single chip, requiring neither fine-
adjustment prism nor beam composition prism.
MODEL
7155/7165/7255/7272 SERVICE MANUAL
MANUAL REVISED EDITION
2-D-2

[3] M15 (Polygon) Control

24V1
P.GND
POLM CONT
POLM CLK
POLM LOCK
PRCB
24V/1
5V/2
S.GND
P.GND
DCPS
M15 (polygon) is driven by PMDB (polygon drive
board) and is controlled by PRCB (printer control
board).
1. Operation
a. Explanation of operation
M15 is a 3-phase brushless DC motor which is
driven by the 3-phase bipolar method. The cur-
rent flowing through the coil is switched accord-
ing to the position of the rotor detected by the
position sensor (magnetic sensor) in the motor.
This motor rotates the polygon mirror to scan the
laser beams from LDB (laser driver board) in the
axial direction of the drum. Its rotation is held
constant by PLL control.
b. Rotational speed
M15 is powered by 24 VDC and its rotational
speed is as follows:
In the case of the 7155/7165
Rotational Linear
speed speed
37,795 rpm 320 mm/s
33,070 rpm 280 mm/s
21,850 rpm 185 mm/s
In the case of the 7255/7272
4
Rotational Linear
speed speed
40,748 rpm 345 mm/s
33,070 rpm 280 mm/s
40,748 rpm 172.5 mm/s
DATE PAGE
Dec. 2003 2-D-2
4 4
M15
PMDB
7155 7165
- normal
normal -
thick paper
7255 7272
- normal
normal -
thick paper
METHOD
REPLACEMENT