Structure Of The Sheet Feeder - Canon BJC-2000 Service Manual

Part 4: Technical Reference
BJC-2000

3.5.2 Structure of the sheet feeder

This printer has no paper selection lever on the cut sheet feeder.
If the paper meets specifications, it can be fed without selecting the paper type. The
paper is loaded in the cut sheet feeder such that a corner of it is caught by the paper
separator. When printing starts, the pick-up roller starts to rotate through the drive
of the paper feed motor. Plain paper is fed with its corner held by the paper separator,
and then pushed into the paper feed section. When printing on thick paper like
envelopes, as the paper is stiffer than the return force of the paper separator's spring,
the paper separator is pressed down to feed the paper.
The initial position of the pick-up roller is detected when the flag is sensed by the
pick-up roller sensor on the logic board.
When paper is sensed by the paper end sensor for over a second, it is fed
automatically until it reaches the starting position for printing.
When the paper pick-up operation is executed, if no paper is sensed, it is executed again. If
the paper is still not sensed, it is assessed as a paper feed error.
Paper
Pick-Up Roller
Paper Separater
<Plain Paper Pick-Up.> <Thick Paper Pick-Up.>
Figure 4-19 Paper Pick-up Mechanism
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