Canon iR C6800 Series, Service Manual

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Chapter 7
7-63
1 ITB
2 Reflecting surface
PS1: ITB home position sensor A
PS30: ITB home position sensor B
DCCON: DC controller
Memo:
The side A home position detection signal (I_TOP1A) is the signal used when forming an image for a single page
at a time.
The side B home position detection signal (I_TOP1B) is the signal used when forming images for 2 sides at a time.
The DC controller uses the output of the sensor (PS1 or PS30) that detects the reflecting surface of the ITB first as
indicating the home position for side A. It then assumes the point reached a specific period of time after side A home
position to be side B home position.
The machine uses the following sequence of operation to form images in different printing modes:
Full Color, 1 Print
The machine generates the PVREQ (request) signal for individual colors with reference to the ITB home position
detection signal (I_TOP1A) of side A, used for the formation of an image.
F-7-58
Full Color, 2 Prints, Continuous (2page placement; see Note)
The machine generates the PVREQ (request) signal for individual colors based on the ITB home position detection
signal (I_TOP1B) of side B and the home position detection signal (I_TOP1A) of side A, used for the formation of
an image.
For the 1st side, the image is formed in sequence with reference to I_TOP1A; for the 2nd side, on the other hand, the
images are made in sequence based on I_TOP1B.
F-7-59
Start key
ON
PRINT INTR
PVREQ
Laser
(image formation)
side
A
side
B
Home position
detection signal
M Y C Bk
I_TOP1A I_TOP2A I_TOP3A I_TOP4A
(PS1 or PS30
output)
Start key
ON
PRINT INTR
PVREQ
Laser
(image formation)
side
A
side
B
M M Y Y C C Bk Bk
I_TOP1A
I_TOP1B
I_TOP2A
I_TOP2B
I_TOP3A
I_TOP3B
I_TOP4A
I_TOP4B
Home position
detection signal
( PS1 or PS30
output )