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WRITE UNIT
*2 Positioning
Each laser beam is positioned by the compres-
sion prism and fine adjustment prism.
*3 Laser beam combining
Two laser beams output at right angle to each
other are redirected in the same direction using
the beam combining prism.
Semiconductor laser 1
Semiconductor
laser 2
Laser 1 beam passes
Laser 2 beam
reflected
Beam combining prism
[3] M17 (Polygon) Control
M17 EM
M17 CLK
M17 CONT
PRCB
24VDC
PGND
DCPS2
M17 (polygon) is driven by the PMDB (polygon driver
board) and is controlled by the PRCB (printer control
board).
1. Operation
a.
Explanation of operation
M17 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 LDB1 and 2 (laser driver
boards 1 and 2) in the axial direction of the drum.
Its rotation is held constant by PLL control.
b.
Rotational speed
36VDC is used to drive M17. The rotation speeds
are as follows:
Resolution
400 dpi
600 dpi
2. Signals
a.
PRCB input signals
(1) M17 EM (PMDB to PRCB)
This signal indicates the clock synchronization
state of M17.
[L]: Synchronous (normal)
[H]: Asynchronous (abnormal)
2-D-2
SGND
24VDC
M17 MAG A'
M17 MAG A
M17 MAG B'
M17
M17 MAG B
M17 MAG C'
M17 MAG C
M17 DRIVE C
M17 DRIVE B
M17 DRIVE A
PMDB
Rotational speed (rpm)
24,803.1 rpm
37,204.7 rpm
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