Ricoh D104 Field Service Manual page 664

6. Troubleshooting
Action Procedure
1. If the grainy images only appear in black image areas with Printer Full Color mode, select "CMY
+K" with the PCL printer driver. For details, see "Action 1" described below.
2. Change the paper transfer bias. For details, see "Action 2A" described below.
3. Increase the amount of the toner per area (M/A). For details, see "Action 3" described below.
4. Ask a customer to change paper from high resistant paper to more smooth paper.
Cause 2: Grainy Image on Humid Paper
The surface resistance of paper such as humid paper is low, and the electrical field for the paper transfer
is weak.
Action Procedure
1. Ask a customer to keep paper in dry condition.
2. Turn on the tray heater if it has already been installed or ask a customer to install the optional tray
heater.
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3. If the grainy images only appear in black image areas with Printer Full Color mode, select "CMY
+K" with the PCL printer driver. For details, see "Action 1" described below.
4. Change the paper transfer bias. For details, see "Action 2A" described below.
5. Increase the amount of the toner per area (M/A). For details, see "Action 3" described below.
Cause 3: Grainy Image on 2nd Side of Paper
This may be caused by the resistance value difference from 1st side and 2nd side paper. The resistance
of the 2nd side paper is changed after the paper has passed the fusing unit. As a result, the resistance
of 2nd side paper which has passed the fusing unit is out of the range for the standard resistance of
paper.
Action Procedure
1. If the grainy images only appear in black image areas with Printer Full Color mode, select "CMY
+K" with the PCL printer driver. For details, see "Action 1" described below.
2. Change the paper transfer bias. For details, see "Action 2B" described below.
3. Increase the amount of the toner per area (M/A). For details, see "Action 3" described below.
4. Ask a customer to change paper from rough surface paper to more smooth paper.
Cause 4: Grainy Image on Small Size Paper
The transfer current tends to leak at the non paper area of the paper transfer roller. As a result, insufficient
transfer current causes a grainy image when using small size paper in the high temperature and high
humidity condition.
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