Canon LBP1760P, Service Manual

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V. PICK-UP/FEED SYSTEM
A. Outline
Presence of paper in the multi-purpose tray is detected by the multi-purpose tray paper sensor
(PS105). Presence of paper in the cassette is detected by the cassette paper sensor (PS101).
The paper size in the cassette and whether the cassette is installed are detected by the three
switches (SW600, 601, 602) on the paper size detection PCB.
In case of paper pick-up from the cassette, while the main motor rotates, the pick-up sole-
noid (SL101) and feed roller clutch (CL101) are turned ON. Then, cassette pick-up roller, cas-
sette feed roller, separation roller and feed rollers rotate, and a sheet of paper is fed into the
printer.
In case of paper pick-up from the multi-purpose tray, while the main motor rotates, the multi-
purpose tray pick-up solenoid (SL102) is turned ON. Then, the multi-purpose pick-up roller
rotates, and a sheet of paper is fed into the printer.
When the paper reaches the pre-transfer roller after passing through the pre-feed sensor
(PS102), its skew is adjusted by hitting the registration arm.
In the prescribed period of time after the top of page sensor (PS103) detects the leading edge
of the paper, the VERTICAL SYNC signal (/TOP) is sent from the engine controller to the video
controller.
As the paper is fed during this time, the leading edge of the image on the drum matches the
leading edge of the paper by sending the /VDO signal in a certain period of time after the video
controller receives the /TOP signal. The paper goes through transfer, separation, fixing, and
delivery unit and is delivered onto the face-up or face-down tray.
There are four photointerrupters (PS102, PS103, PS106, PS501) on the paper path for detect-
ing arrival or passing of the paper.
If the paper does not reach or pass these sensors within the prescribed period of time, the
microprocessor on the engine controller assesses a paper jam and notifies the video controller
of the jam occurrence.
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CHAPTER 2