Canon CLBP-460PS, Service Manual

Page: 135 / 566

B. Paper Pick-up
1. Cassette pick-up
a. Outline
The presence of the paper on the cassette is sensed by the cassette paper sensor (PS8). The
paper size and the presence of a cassette are detected by three paper size detection switches
(SW801 to 803). Combinations of paper size detection switches are listed in Table 2-5-2.
When it detects the HOME POSITION signal (HP1) for the first color image forming after the
PRINT signal (/PRNT) is received, the DC controller drives the pick-up motor (M2).
After the prescribed period of time, the cassette pick-up solenoid (SL2) is turned ON to trans-
mit the rotational force of the pick up motor to the cassette pick-up roller and the paper is picked
up by its rotation.
After the paper is separated from any extra sheets by the separation roller, it is fed into the
printer by rotation of the cassette feed roller and the feed roller.
After passing through the registration paper sensor (PS2), the paper reaches the registration
roller. The registration roller is not rotating at this time, so the paper temporarily stops in the
registration roller position. Its leading edge is curled and any skew is corrected.
In a specified period of time after detecting the home position for paper refeed (see note 1),
the DC controller drives the registration clutch (CL1) to feed the paper to the secondary trans-
fer unit. The leading edge of the image on the intermediate transfer belt is matched with the
leading edge of the paper (see note 2).
The paper is then fed to the fixing and delivery unit.
Notes 1: The home position signal for the paper refeed is the same as that for the fourth color
for full-color printing (HP4) and the first color for mono-color printing (HP1).
2: If the feeding speed is changed according to the media data specified by the video
controller (see P.2-76), the speed of each motor (pick-up, fixing, and drum) is changed
when CL1 is driven.
2 - 77
CHAPTER 2