Canon CLBP-460PS, Service Manual

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2. Operation
When the power is switched ON, the printer enters the WAIT state.
When the printer is ready for operation after the WAIT period, the DC controller sends a
READY signal (/RDY) to the video controller to notify it that the printer is ready.
When the /RDY signal is “L” and data for a page is prepared, the video controller sends the
PRINT signal (/PRNT) to the DC controller.
When the DC controller receives the /PRNT signal, it starts the operation of the INITIAL
ROTATIONS (INTR) period.
At the end of the INTR period, the DC controller sends the TOP OF PAGE signal (/TOP) to the
video controller.
The video controller sends the VIDEO signals (/VDO0 to /VDO7) synchronized with the LINE
SYNC signal (/LSYNC) and the /TOP signal from the DC controller to the gate array. The DC
controller reads the /VDO0 to /VDO7 signals in synchronization with the PRINTER CLOCK sig-
nal (PCLK), then sends them to the laser driver PCB in the laser/scanner unit. The laser driver
PCB generates the PWM-modulated LASER DRIVE signal (laser/scanner internal signal) which
switches the laser diode ON and OFF to produce a modulated laser beam.
The resulting laser beam is scanned repeatedly across the photosensitive drum to form the
latent electrostatic image of the original image.
The latent image formed on the photosensitive drum is developed with toner, and transferred
to the intermediate transfer belt. In full color mode, this process is repeated on the intermedi-
ate transfer belt in the order of Bk (black), M (magenta), C (cyan), and Y (yellow). The toner
image transferred to the intermediate transfer belt is transferred to the paper and delivered onto
the face-down tray or face-up tray.
The DC controller checks for another /PRNT signal from the video controller during the pri-
mary transfer to the intermediate transfer belt.
If there is no /PRNT signal, the printer ends the PRINT sequence and begins the operation of
the LAST ROTATIONS period (LSTR). At the end of this period, the printer enters the STANDBY
(STBY) state.
If another /PRNT signal arrives during printing, however, the PRINT sequence continues.
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CHAPTER 2