Pick-Up And Feeding - Canon LBP1760P Service Manual

B. Pick-up and Feeding
The paper feeder picks up the paper from the cassette installed in the paper feeder and feeds the
paper to the printer. The flow of the paper is as shown below.
The paper size and the presence of the cassette are detected by the three switches (SW801,
802, 803) on the paper feeder driver PCB. The relationship between the switch combinations
and the paper sizes is the same as that of the printer.
The paper feeder is driven by the main motor (M101) of the printer via the gear.
When the /PRNT signal is sent to the engine conroller from the video controller, the main
motor (M101) of the printer starts rotation. When the main motor reaches its prescribed speed,
the paper feeder driver PCB receives the pick-up command from the engine controller, and the
paper feeder pick-up solenoid (SL801) is turned ON. As a result, the pick-up roller, feed roller,
and separation roller are driven by the main motor rotation.
The pick-up roller make one rotation by the solenoid and picks up the paper inside the cas-
sette. Then, the unnecessary sheets are removed by the separation roller and the picked up
paper is fed to the pre-feed sensor (PS102) of the printer.
The CPU on the engine controller PCB detects the conditions of the PS102 for a prescribed
period of time after the pick-up starts. If the PS102 does not detect no paper within the pre-
scribed time, the CPU turns OFF the feed roller clutch (CL101) to stop the paper in the pre-
scribed time after the top of page sensor (PS103) detects the paper present condition of the pre-
ceding paper. When the top of page sensor (PS103) detects the trailing edge of the preceding
paper, the CPU resumes feeding the stopped paper. By this, the between-page distance appro-
priate for the continuous printing is achieved.
The paper then reaches the registration arm where its skew is corrected, goes through trans-
fer, separation, fixing and delivery unit and is delivered to the tray.
Figure 2-7-2
CHAPTER 2
2 - 59