Canon iR C6800 Series, Service Manual

Page: 195 / 1404

Chapter 5
5-13
5.3.4.2
Points of Measurement Used for Original Size Identification
0002-5150
For main scanning direction, the machine moves the No. 1 mirror base to the following points in relation to the
location of the original to measure the levels of the CCD. For sub scanning direction, the machine checks the states
of the sensors arranged as follows:
F-5-17
To raise the accuracy of original size identification (as when the original is displaced while the ADF is closed), the
machine makes use of the following 2 types of mechanisms:
1.Presence/Absence of an Original at 2 Points (for each point of measurement)
For each point of measurement in main scanning direction, the machine checks the presence/absence of an original
with reference to the CCD output at 2 points near the point of measurement.
F-5-18
T-5-6
Result of measurement Result of detection
A B
no no original absent
yes no original present
no yes original present
yes yes original present
Point of original
detection 3
Point of original
detection 4
Point of original
detection 1
Print of original
detection 2
B5
B6
A5
A4
B5R
A4R
B4
A3
CCD original detection position
Point of original
detection 2
Point of original
detection 1
Point of original
detection 3
LTRR STMT
LTR
LGL
279.4×431.8mm
(11"×17")
CCD original detection position
Original
sensor 3
AB-Configuration Inch-configuration
STMTR
Original
sensor 1
Near 4 mm
Near 13 mm
1A:additional point
of detection
Original size
border line
Original size
border line
1B:conventional point
if detection