Ricoh A230, Service Manual, Page: 95 / 1134

DRUM CHARGE
2-32
A230/A231/A232 SM
If the humidity drops, the drum potential goes up even if the charge roller voltage
supply stays the same (efficiency of voltage transfer decreases with increased
humidity). As a result, more toner is transferred to ID sensor pattern [B]. If the
sensor output reaches a certain point, the drum charge voltage will be reduced.
To determine whether to change the drum charge roller voltage, the machine
compares Vsdp with Vsg.
•
Vsdp / Vsg > 0.90 = Reduce the drum charge voltage by 30 V
•
Vsdp / Vsg < 0.85 = Increase the drum charge voltage by 30 V
NOTE: The maximum drum charge roller voltage is – 2 kV.
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 charge roller voltage can be increased for paper fed from the
bypass tray. The voltage corrections are adjusted with SP 2-914-1 and 2. The
width thresholds for these adjustments can be adjusted with 2-309-1 and 2-309-2.
Charge roller input voltages
Paper width from 216 mm to 297 mm: SP2-001-1
Paper width from 150 mm to 216 mm: SP2-001-1 + 50 V (adj. with SP2-914-2)
Paper width below 150 mm: SP2-001-1 + 250 V (adj. with SP2-914-1)
Paper width limits
150 mm limit: SP2-309-1
216 mm limit: SP2-309-2
Similar voltage adjustments are available for development bias and transfer
current.