Ricoh A230, Руководство по обслуживанию, Страница: 100 / 1134

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DEVELOPMENT
2-37
A230/A231/A232 SM
2.6.4 DEVELOPMENT BIAS
This machine uses a negative development system, in which black areas of the
latent image are at a low negative charge (about -150 V) and white areas are at a
high negative charge (about -950 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 roller throughout the image development process. The bias is applied
to the development roller shaft [B] through the bias terminal spring [C] and bias
terminal [D].
The development bias voltage (-600 V) can be adjusted with SP2-201.
Correction for paper width and thickness (bypass tray only)
The bypass tray can be used for narrower paper than the paper trays. Also, thicker
paper can be used, as well as OHP sheets. In these cases, some copy quality
problems may occur.
To deal with this, the development bias can be increased for paper fed from the
bypass tray. The voltage corrections are adjusted with SP 2-914-3 and 4. The
width thresholds for these adjustments can be adjusted with 2-309-1 and 2-309-2.
Development bias voltages
Paper width from 216 mm to 297 mm: SP2-201-1
Paper width from 150 mm to 216 mm: SP2-201-1 + 50 V (adj. with SP2-914-4)
Paper width below 150 mm: SP2-201-1 + 200 V (adj. with SP2-914-3)
Paper width limits
150 mm limit: SP2-309-1, 216 mm limit: SP2-309-2
Similar voltage adjustments are available for charge roller input voltage and
transfer current.
A230D404.WMF
[A]
[B]
[C]
[D]
Rev. 7/98