Canon CLBR 460ps Service Manual page 116

CHAPTER 2
c. ITB unit life detection
This detector determines whether the end of the ITB unit life has been reached.
The ITB counter unit on the side of the ITB unit conducts the ITB unit life detection. The ITB
counter unit consists of 12 gears with different numbers of teeth and the ITB unit life detection
lever. The gears transmit the rotation of the intermediate transfer belt to the ITB counter gear.
The ITB counter gear moves the ITB counter lever when the end of the ITB unit life is reached.
The position of the ITB counter lever is monitored by the ITB unit life sensor (PS1) in the print-
er.
Normally, the life detection lever does not block light from PS1 and the ITB UNIT LIFE
DETECTION signal (/ITBW) is "H". When the number of the intermediate transfer belt rotations
reaches the specified value (about 100,000 rotations), the ITB counter lever slides to lift up the
life detection lever. The life detection lever blocks light from PS1 and /ITBW goes "L".
If /ITBW is "L" during WAIT period after power-ON or the ITB unit drawer open/close, the DC
controller determines that the end of the ITB unit life has been reached and sends the ITB unit
life warning to the video controller.
ITB unit
ITB counter unit
ITB counter gear
ITB counter Lever
ITB unit life sensor (PS1)
< When the end of the ITB unit life has not been reached >
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ITB counter unit
ITB unit life detection lever
Figure 2-4-14
Intermediate transfer belt
feed roller
< When the end of the ITB unit life has been reached >
Gears 1 to 11