Canon 1000 Service Manual page 185

d. Detecting the Thickness of Paper
When picking up paper from the multifeeder, the CLC1000 uses the paper thickness detecting roller and
the reflecting type paper thickness sensor in the multifeeder pick-up assembly to check the thickness of
paper; in particular, it controls the fixing speed to ensure proper fixing of images on thick paper.
The paper thickness detecting roller rotates by the drive of the pick-up motor (M10) coming by way of the
paper thickness detecting roller clutch (CL7).
Under the control of the CPU on the DC controller PCB, the light of the LED of the paper thickness
sensor is shone against the paper thickness detecting roller (upper) when paper is not moving through the
paper thickness detecting roller. The difference in the angle of the light of the LED reflected by the paper
thickness detection roller (upper) lets the paper thickness sensor to identify the shift of the paper detecting
roller (upper) caused by the thickness of paper.
The shift is subjected to computation to find out the thickness of paper: 'roller position when paper is
present' - 'roller position when paper is absent' = paper thickness.
Pick-up motor
controller PCB
Pick-up
motor
Paper thickness
detecting roller
clutch
Pick-up motor controller PCB
COPYRIGHT © 2001 CANON INC.
DC controller PCB
J2213A J2207A
-1
-9
Multifeeder relay PCB
M10
Paper thickness
detecting roller (upper) LED
CL7
CANON CLC1000/1000S/3100 REV.2 MAY 2001 PRINTED IN JAPAN (IMPRIME AU JAPON)
J2207A
-8
Paper thickness
sensor (PTS1)
Paper thickness detecting roller (lower)
Figure 3-611
3. OPERATION AND TIMING
J2207A
-10
Photo diode array
Pressure spring
(front)
3-141