Belt Mark Detection; Transfer Roller - Ricoh U-C1 B051 Service Manual

PHOTOCONDUCTOR UNIT (PCU) 26 July 2002

Belt Mark Detection

[B]
[A]: Belt mark sensor
[B]: Mark
[A]
B051D315.WMF
The belt mark sensor is a reflective photosensor.
To exactly synchronize the four mono-color toner images on the image transfer
belt, the belt mark sensor [A] monitors the belt speed. The sensor detects the light
reflected by the marks [B] at the rear end of the belt (25 marks per rotation; mark
frequency: 21 mm). The sensor output is used to control the belt speed.

Transfer Roller

[A]
[B]
[A]: Transfer roller
[B]: High voltage supply board
[C]: Terminal plates
[C]
B051D316.WMF
The transfer roller [A] attracts toner from the OPC belt to the image transfer belt by
using a positive charge.
The terminal in the middle of the PCU contacts the terminal on the transfer roller
shaft when the image transfer belt unit is installed in the PCU.
The current is adjusted based on environmental temperature and humidity.
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