Precautions - Toshiba e-STUDIO350 Service Handbook

3.6.2

Precautions

[A] Developer bias
Note for adjustment
Adjust the developer bias if fogging occurs over the entire image even though the main charger grid
voltage and toner density are appropriate. However, the following may occur if the developer bias is
lowered too much:
• Image contrast becomes low.
• Image is patchy or blurred.
• The carrier in the developer material adheres to the photoconductive drum, causing scratches
around the cleaner.
[B] Transfer
Items to check before adjustment
Blotched image or poor transfer can be also caused by matters other than defective adjustment of
transfer output. Check the following items before adjusting the transfer charger. If there is no problem,
adjust the output of the transfer charger.
• Is the charger wire incorrectly installed or dirty? Is the transfer guide deformed?
• Is the developer unit properly installed? Is the developer magnetic brush in contact with the drum?
Is the developer sleeve rotating during printing? Is the toner density low?
• Is the copy paper fed straight? Is the copy paper abnormally moist?
• Is the rotation of the registration roller normal?
• Is the output of the transfer guide bias normal?
• Is the separation output different from the set value?
• Is the developer bias value an appropriate one?
• Are the transfer/separation charger case and the drum shaft grounded? Is the high-voltage trans-
former grounded?
• Is the transfer insulation film (transparent film attached to the transfer guide) damaged or deformed?
Note for adjustment
When blotched image appear:
• If blotched image appear in halftone areas, lower the transfer output value. Remember that transfer
performance becomes low if the transfer output value is lowered too much.
When transfer is poor:
Increase the transfer output value under the following conditions. Remember that blotched image
appear if the transfer output value is increased too much.
• Transfer is poor even though the charger wire is not dirty.
• Thick paper has been frequently used.
Note: Note:
The Thick Paper Mode is recommendable when thick paper is used.
Increase the transfer output value only to prevent a poor transfer without selecting the Thick
Paper Mode when thick paper is frequently used.
e-STUDIO350/352/353/450/452/453
ADJUSTMENT
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