Controls (Reader); Controls - Canon Color Image Reader-F1 Service Manual

2
Technology > Controls (Reader) > Controls > Detecting the Size of Originals

Controls (Reader)

Controls

■ Enlargement/Reduction
● Magnifications in Main Scanning Direction
An image is read at 100% in main scanning direction. Magnification variation and its data
process are controlled on main controller PCB 2.
● Magnification in Sub Scanning Direction
To vary the magnification of sub scanning direction, the machine operates as below
depending on the original reading methods and the magnifications.
To suite the selected rate of magnification, the machine changes the speed of original reading
and executes data processing on main controller PCB 2.
e.g.) Reduction to 25%: an original is read at 243mm/s, and the data is processed for 25%
reduction (skipping for 4/1) by the main controller PCB 2.
e.g.) at 100%: an original is read at 243mm/s.
Operation
25% to 50%
Speed change of original reading 260
(mm/sec)
Digital magnification process (%) on 25 to 50
the main controller PCB 2
2 Technology > Controls (Reader) > Controls > Detecting the Size of Originals
Magnifications
50.1% to 199.9% 200% to 400%
260 130
50.1 to 199.9 100 to 200
T-2-2
■ 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 (AB type: 12 points measurement, inch type: 6 points
measurement)
• Sub scanning direction: Reflection type photo sensor (AB type: 1 point, inch type: 1 point,
AB/inch type: 2 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.
2-4
2-4