Points Of Measurement Used For Original Size Identification - Canon imagerunner C5180 Service Manual

Specifically, the following takes place:
1) External Light Search (main scanning direction only)
While keeping the scanning lamp off, the machine measures the level of the CCD at specific points in main
scanning direction.
2) Sensor Output Level Detection
The machine turns on the scanning lamp, and measures the sensor output at specific points. It then checks
combinations of these measurement to find the size of the original.

6.3.4.2 Points of Measurement Used for Original Size Identification

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:
AB-Configuration
Point of original
detection 1
B6
Print of original
A5
detection 2
B5
Point of original
detection 4
CCD original detection position
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.
Original size
border line
Original size
border line
Original
sensor 1
B5R
A4R
B4
A3
A4
Near 13 mm
Near 4 mm
Inch-configuration
Point of original
detection 1
STMTR
Point of original
detection 2
STMT
Point of original
detection 3
CCD original detection position
F-6-17
1A:additional point
of detection
1B:conventional point
if detection
F-6-18
Chapter 6
Original
sensor 3
LTRR LGL
279.4×431.8mm
LTR
(11"×17")
6-13