Ricoh A172 - Page 442

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Field Engineering Bulletin
Digital Color Series
TECHNICAL OPERATIONS
BULLETIN NO: SDC206/E - 005 DATE: 10122197
I
Subject: FIREFLY SPOTS - UNSTABLE CARRIER
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n Copy Quality
q Electrical
0 Mechanical
q Modification
0 Safety Information
0 Technical Information
0 General Information
Model - Product/Serial Numbers Affected
1 Modification Schedule
SDC206
SDC206/E
I
q Mandatory
0 Scheduled Visit
I
q Next Call
q Next PM
q As Necessary
Install Time
Problem
Firefly spots (light spots) in the solid or halftone image area.
Cause
Unstable carrier particles attracted to the drum surface block prevent proper toner transfer to the transfer belt.
Note
A Similar image symptom may occur when condensed toner is attracted to the drum surface. The condensed
toner appears in the center of the light spot. The cause of this symptom is different and is not corrected with
the following procedure.
Solution
Follow the steps below to remove the unstable carrier in the developer.
1. Open SP mode 2-2 Test Pattern Condition. Set the test pattern condition and select full dot
pattern.
2. Make an 11 xl 7” single color copy(s) using the color(s) which has light spots.
3. Open SP mode 3-3 Drum Potential Control Output and note VB actual data of the color which has
light spots.
4. Open SP mode l-4 Voltage Setting for P-con Reset Mode and input VB actual data + 200 to
the VB for color(s) which has light spots. Input VB actual data + 355 to the VG of the color(s)
which has light spots.
Example: If VB actual is -3OOV, input -500V to the VB and -655V to the VG.
5. Open SP mode 4-l Auto Process Control Selfcheck and select reset.
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