Ricoh CH-C1, Service Training

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352
Ch-C1 Training
Slide 352
Toner Supply Control

If toner supply is calculated based on the amount of toner
used in covered areas only, errors can increase, especially
when changes occur in ambient temperature and drum
characteristics.

This makes it difficult to control toner supply only with
pixel counts to maintain constant image density.

Rather than depend on pixel counts in covered areas,
several ID sensor patterns (Default: 10 patterns) are
created on the drum and ITB between sheets.

The machine uses two readings to calculate Vtref

Vsg (reflectivity of the bare surface of the ITB)

Vsp (reflectivity of the pattern areas covered with toner).

The value of Vtref is then used to set the toner reference
voltage for the TD sensor.

This reference voltage is frequently updated with fresh
readings of the patterns to stabilize the amount of toner in
the development unit.
No additional notes