Toshiba 2460 Service Handbook page 49

1.9.2 Precautions
(1) Developer bias
Caution during Adjustment
If fogging appears over the entire surface even though the grid voltage and toner density are appropri-
ate, adjust the developer bias on the control panel. The following defects may occur if the developer
bias is lowered too much:
• Image contrast becomes low.
• Image is patchy or blurred.
• Developer carrier adheres to the photosensitive body, making it easier for scratches to occur or the
surface of photosensitive body by the cleaner blade.
(2) Transfer
Items to Check before Adjustment
Pockmarks or defective transfer also occur in defects besides transfer output adjustment defects. If
this happens, check the following items. If an error is not found after carrying out the following checks,
adjust the output.
• Is the charger wire out of position or dirty? Is the transfer guide deformed?
• Is the developer unit connected? Are the developer magnetic brushes contacting with the drum?
Is the developer unit rotating during copying? Is the toner density low?
• Is the copy paper bending as it is being fed in? Is the copy paper abnormally moist?
• Is the aligning roller rotating normally?
• Is the transfer guide bias outputing?
• Is the separation output deviating from the set value?
• Is the developer bias an appropriate value?
• Is the transfer/separation charger case earthed? Is the photosensitive drum (shaft) earthed? Is the
transfer/separation transformer earthed?
• Is the transfer charge limit plate (transparent film) damaged or deformed?
Caution during Adjustment
1When pockmarks occur:
• If pockmarks are occurring in halftone areas, lower the transfer output value. However, note that if
the transfer output value is lowered too far, the transfer performance also will be reduced.
2When defective transfer occurs:
Increase the transfer output value under the following conditions. However, note that if the transfer
output value is raised too far, pockmarks will occur.
• If defective transfer occurs even though the charger wire is not dirty, and
• If thick paper is frequency used.
• The adjustment code varies according to where pockmarks occur. Select the required adjustment
code while referring to the following diagram.
Adjustment code
Copy leading edge
2460 ADJUSTMENT
Approx. 14 mm Approx. 10 mm
"220" "221"
1 - 46
"222"
Copy trailing edge
September 1997 © TOSHIBA CORP.