Ricoh SP 200 Specifications download pdf (Page 52)

4.5.4 Development Bias

This machine uses a negative-positive development system, in which black

areas of the latent image are at a low negative charge (about -140

50 V)

and white areas are at a high negative charge (about -900 V).

To attract negatively charged toner to the black areas of the latent image on

the drum, the high voltage supply board [A] applies a bias of -600 volts to the

development rollers throughout the image development process. The bias is

applied to the development roller shaft [B] through that shaft’s gear [C].

The development bias is kept at 0V until the latent image comes to the

development roller. This is to prevent toner from transferring to the area of

drum near the development roller, which has not yet been charged. The

development bias is then increased to -600 V at the same time as the

development clutch turns on.

The development bias voltage (-600 V) can be adjusted with SP2-201.

[A]

[C]

[B]

A193D534.wmf

1 August 1996 PCU (PHOTOCONDUCTOR UNIT)

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Ricoh SP 200 Specifications Page 52