Canon LBP-860 Service Manual page 72

CHAPTER 2
B. Operation
When the power is switched ON. the
printer enters the WAIT state. When the
s i g n a l (/KDYl is sent from the DC
controller to notify the video controller that
the printer is ready. When the /RDY signal
is "L" and data for a page is ready, lhe
video controller sends the PRINT signal
When the DC controller receives the
ROTATIONS (INTR] operations. A certain
lime after the INTR period, the DC
controller sends the VERTICAL SYNC
REQUEST signal (/VSREQ) to the video
controller. After video controller receives
the /VSREQ signal, it sends the VERTICAL
SYNC signal (/VSYNC) to the DC controller.
When the DC controller receives the
sequence.
The video controller synchronizes the
VIDEO signal (VDO) with the HORIZONTAL
SYNC signal (BDJ and the VERTICAL SYNC
signal (VSYNC) sent from the DC controller.
and sends it to the DC controller. In
response to the /VU0 signal, the DC
controller generates the LASER DRIVE
signal (/VDATA) that switches the laser
diode ON and OFF. and sends it to the
laser driver.
The resulting laser beam is scanned
repeatedly across lhe photosensitive drum
by the mirror drum to form a latent
electrostatic image of the original data, as
described earlier.
When a page is being printed, the DC
controller checks for another /PRNT signal
from the video controller. If none has
arrived by the end of the PRINT period, the
DC controller begins the LAST ROTATION
period, the printer enters the STANDBY
If another /PRNT signal arrives during
printing. however. the print sequence
continues. The LAST ROTA'IlONS operations
are performed, and the printer enters the
Download Service Manual and Resetter Printer at http://printer1.blogspot.com
standby state.