4-Channel High-Speed Reading Ccd - Canon iR105 Service Manual

3.3 4-Channel High-Speed Reading CCD

To support high-speed reading at 80 ipm, the machine uses a 4-channel high-speed read-
ing CCD. It consists of two CCDs connected to form a single entity (each, half length of a
common CCD); the entire CCD is divided in the middle into first half and last half.
Reading starts simultaneously at both left and right sides, thereby cutting the data transfer
time required for reading by half and ultimately enabling high-speed reading.
The image data is divided into 4 channels: first-half even-numbered pixels, first-half odd-
numbered pixels, last-half even-numbered pixels, and last-half odd-numbered pixels. The
following diagram shows how CCD data is transferred:
Direction of charge transfer
Clock pulse C
Output
unit C
Light-
receiving
7500 7499 7498 7497
unit
Output
unit D
Clock pulse D
Direction of charge transfer
COPYRIGHT© 2001 CANON INC.
Transfer unit C
3754 3753 3752 3751
Transfer unit D
F02-303-01
2000 2000 2000 2000 CANON iR105 REV.0 JULY 2001
CHAPTER 2 NEW FUNCTIONS
Direction of charge transfer
Transfer unit A
3750 3749 3748 3747
Transfer unit B
Direction of charge transfer
Clock pulse A
Output
unit A
CCD
shift
4 3 2 1
pulse
Output
unit B
Clock pulse B
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