Canon imagePRESS C1 Service Manual - page 421
Chapter 7
7-72
F-7-89
[1] ITB
[2] Reflecting surface
[3] Side driver PCB
PS1: ITB home position sensor A
PS2: ITB home position sensor B
DC-CON: DC controller
MEMO:
A-surface home position (I_TOP1A) is the signal to form images by one surface on the ITB.
B-surface home position (I_TOP1B) is the signal to form images by two surfaces on the ITB.
The DC controller determines the first sensor output (PS1 or PS2) that detects the reflecting surface on the ITB after receiving the print instruction as A-surface
home position.
It then assumes the point reached a specific period of time after side A home position to be side B home position.
The following are the timing of image forming for each print mode.
1. 5 Full-color one-sheet print
PVREQ signal (image demanding signal) for each color is produces based on A-surface ITB home position detection signal (I_TOP1A). The image is formed based
on this PVREQ signal.
F-7-90
2. 5 Full-Color 2-Sheet Continuous Printing (2-image printing) (See after-mentioned note)
PVREQ signal (image demanding signal) for each color is produced based on the A-surface ITB home position detection signal (I_TOP1A) and the B-surface ITB
home position detection signal (I_TOP1B). The image is formed at constant speed based on this PVREQ signal.
The image is formed in order based on I_TOP1A for the first surface, I_TOP1B for the second surface.
PS2
PS1
PS2
[2]
I_TOP_SNS_2
I_TOP_SNS_1
[3]
DC-CON
J3403
J1193
[1]
[2]
[2]
Start key ON
ON
INTR
PVREQ
Laser
(image formation)
A-surf
ace
B-surf
ace
Home position
detection signal
L
Y
M
C
I_TOP1A
I_TOP2A
I_TOP3A
I_TOP4A
Bk
I_TOP5A
(PS1 or PS2 output)