Canon LBP-2000 Service Manual page 75

CHAPTER 2
2. Scanner pre-rotation
To ensure that the rotation of the scanner motor stabilizes fast at time of start-up, the machine
rotates the scanner motor by sending the scanner pre-rotation command about 4.25 sec (varies
depending on the image data reception time) in advance of the pickup command (/PRINT) sent by
the video controller to the ASIC, ultimately ensuring the correct positioning of the image leading
edge.
The following diagrams show the timing of operation used for delivery (A4, horizontal); the timing,
however, varies depending on the timing of previous delivery and the printer settings:
Scanner Pre-Rotation ON
Scanner
Start of print
pre-rotation
Scanner Pre-Rotation OFF
Start of print
The machine issues the scanner pre-rotation command for the following condition:
• There is no previous image data and, in addition, no paper is being delivered and no page is
being delivered.
2 - 36
/PRNT
4.3 sec (approx.)
/PRNT
Figure 2-3-5
End of delivery
9.1 sec (approx.)
12.6 sec (approx.)
End of delivery