Canon 1730, Service Manual

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Technical Explanation > Original Exposure and Feed System > Controls > Enlargement / Reduction
Technical Explanation > Original Exposure and Feed System > Controls > Enlargement / Reduction
● Analog Control Performed by the CIS
The flow of analog image processing performed by the contact image sensor (CIS) is as
follows:
a. The light reflected by the original is collected by the rod lens array.
b. The light is received by the original scan sensor array.
c. The original scan sensor array converts the received light to an electric signal and outputs
it.
The original scan sensor array consists of eleven channels (units).
Each channel is provided with an output correction table to output an image signal after
performing gain correction for the input brightness signal.
Driv
er c
ircu
it
11
Original scan sensor
channel x11
3
2
1
468 pixels
5148 pixels
F-2-22
■
Enlargement / Reduction
● Magnification Change in Main Scanning Direction
In book mode or ADF mode
In the main scanning direction, image is read at 100%; thereafter, the data is subjected to
processing by the main controller PCB to suit the selected reproduction ratio.
● Magnification Change in Sub Scanning Direction
The magnification in sub scanning direction is changed as follows:
1) In book mode
Image is read at original scan speed kept at 160 mm/sec; thereafter, the data is subjected
to processing by the main controller PCB to suit the selected reproduction ratio.
2) In ADF mode
Image is read at original scan feeding speed kept at 320 mm/sec; thereafter, the data is
subjected to processing by the main controller PCB to suit the selected reproduction ratio.