Canon LBP5000 Series, Service Manual

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Chapter 2
2-7
3) If the phase of /BDI12 is behind that of the phase reference clock signal, the DC controller generates /SCNACC12; if ahead, it generates /SCNDEC12 to correct
any variation in rotation between lines.
2.3.3.4 Fault Detection
0010-6051
LBP5000 / LBP5100
The CPU monitors the frequency comparator of the ASIC to find out whether the scanner motor is rotating at a specific speed.
The CPU will identify any of the following conditions as the presence of a fault in the scanner motor, thus stopping the printer engine and, at the same time, indi-
cating 'E100' in the status widow.
1. Scanner Motor Start-Up Error
When the scanner motor is starting up, the machine does not detect a scanner ready state within 5 sec.
2. Scanner Rotation Error
While the scanner motor is being rotated normally, the cumulative period of time during which the frequency of the /BDI signal deviates from a specific
frequency range reaches a specific value (in terms of print distance, about 23 mm).
If this condition occurs while image mask control is deactivated, the machine will identify it not as a fault but as a BD error.
MEMO
While the scanner motor is rotating normally and image mask remains deactivated, the machine will identify a BD error if the frequency of the /BDI signal once
deviates from a specific frequency range.
2.4 IMAGE FORMATION SYSTEM
2.4.1 Overview/Configuration
2.4.1.1 Outline
0010-6054
LBP5000 / LBP5100
The image formation system is the core of the machine, in which toner images are formed and transferred to print paper.
The machine's image formation system is controlled by the DC controller PCB. When the print command arrives from the video controller PCB, the DC controller
PCB controls the laser/scanner unit and the high-voltage power supply circuit to form a print image according to the video signal (VDO, /VDO).
The machine's cartridges are equipped with a memory tag that reads and writes data to suit instructions from the DC controller by way of the memory controller PCB.