Enlargement/Reduction; Detecting The Size Of Originals - Canon D1 Service Manual

2
Technology > Controls (Reader)

■ Enlargement/Reduction

● Magnifications in Main Scanning Direction
In book mode/ADF mode
An image is read at 100% in main scanning direction. Magnification variation and its data
process are controlled on main controller2 PCB.
● Magnification in Sub Scanning Direction
In book mode/ADF mode
An original is read at 140mm/s and the data is processed by the main controller PCB 2.

■ Detecting the Size of Originals

● Overview
The machine identifies the original size by the combination of measurement result of reflection
light from the reflection sensor and specific points of CCD. Also to identify it accurately even
though an original moves when ADF is closed, the machine measures 2 points for each size.
- Main scanning direction: CCD
- Sub scanning direction: Reflection type photo sensor (AB type: 1 point, inch type: 1 point )
The followings are the procedures of original size identification.
1) External light search (main scanning direction only)
According to the LED status, the machine identifies the CCD level of each detection
position in main scanning direction.
2) Output level detection of each sensor
The machine turns on the LED on CCD unit and measures the CCD level of each detection
position in main scanning direction.
Also, turns on the LED on reflection type photo sensor in sub scanning direction and
measures the sensor output.
The original size is identified by the combination of these output result.
● Control Details
For main scanning direction, the machine moves the CCD unit to the following CCD original
detection positions according to the location of original to measure the CCD level of each
detection position. For sub scanning direction, the machine uses the original sensor 0, 1 to
identify sizes.
2 Technology > Controls (Reader)
AB type
Original sensor 0
Original detection
position 1
B5R
B6
Original detection
position 2 A5 A4R
Original detection
B4
position 3 B5
Original detection
A3
position 4 A4
CCD original detection position
1. 2 points original detection at each detection position
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.
* The machine checks if the signal is changed or not from ADF (pressure plate) open to
close at both points of 1A and 1B.
Change in the signal: Yes
Change in the signal: No
Judgment is done by the measurement results of 1A and 1B, and it indicates the presence
of original if either point shows absence (absence). It indicates absence
of original if both signals show Yes (presence).
Borderline of
original size
approx 13mm
Borderline of
original size
Inch type
Original sensor 1
Original detection
position 1
STMTR
Original detection
position 2
LTRR
STMT LGL
Original detection
279.4×431.8mm
position 3
LTR (11"×17")
CCD original detection position
F-2-9
1A=additional
detection point 1
approx 4mm
1B=conventional
detection point 2
F-2-10
2-6
2-6