3: Operation
Colorwriter LSR 2000 Printer
Service Guide
3-23
Scanner system
Figure 3-12
Scanner system
The scanning mirror is a crucial part of the scanner unit. It is
mounted on the scanner motor shaft and rotates with the scanner
motor.
The rotation of the scanner motor is controlled by the scanner
driver, so that the laser beam reflected by the scanning mirror scans
across the photosensitive drum at a constant speed.
When the scanner motor drive signal (/SCNON) and the scanner
clock signal (SCNCLK) are sent to the scanner driver by the DC
controller, the scanner driver rotates the scanner motor.
Scanner motor circuit
The scanner motor is a three-phase, 8-pole DC brushless motor
with a hall element. It is incorporated in a single unit with the
scanner driver which controls it to rotate at a constant speed.
When the printer is turned ON, the oscillation frequency of the
crystal oscillator (X103) is divided by the gate array (IC109) and the
resulting signal is sent as the SCNCLK signal to the scanner driver.
When the /PRNT signal that is sent to the CPU (IC101) on the
DC controller becomes “L,” the CPU sets the /SCNON signal to
“L” via the gate array and rotates the scanner motor.
DC
controller
PCB
/SCNON
Scanning
mirror
Motor
Scanner unit
Scanner
driver
/SCNCLK
/SCNRDY