Canon LBP-860, Service Manual

Page: 50 / 219

CHAPTER 2
D. Scanner
Drive
1. Outline
2-14
The
key part of the scanner motor unit is
the which is a hexagonal
prism with mirror faces. It is mounted on
the scanner motor shaft and turned by the
motor.
The scanner motor is controlled by the
scanner driver to make the laser beam
reflected from the scanning mirror scan
across the photosensitive drum at constant
DC controller
speed.
The scanner driver drives the scanner
motor when it is receiving the SCANNER
MOTOR DRIVE signal from the
DC controller.
2. Scanner motor rotation control
Figure 2-15 shows the scanner motor
control circuit.
The scanner motor is a
DC brushless motor containing a Hall
element, and forms a unit along the
scanner driver, which controls scanner
motor rotation at constant speed.
When the printer power is switched ON,
the oscillation frequency of the crystal
(X202) is divided by the gate array
and the SCNCLK signal is sent to the
scanner driver.
When the signal that is sent to
the CPU on the DC controller
becomes
the CPU sets the
CPU
Gate array
,
motor/
driver
Figure 2-15
2 - 1 3