Ricoh A172 Service Manual page 505

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SUBJECT: LIGHT COPIES
SYMPTOM:
Light copies especially in high image density or poor solid fill areas after Developer replacement (can occur
from around 1K to a few thousand scans). One or more of the following conditions may be observed in this
period.
1. Development gamma (SP Data Output page 3) may be high (around four or more).
2. Vcnt compensation value (difference between Vcnt0 and Vcnt on SP Data Output page1) is large.
3. Vt is not too different from Vref and does not look abnormal.
4. Vk is high (around 15V or more).
CAUSE:
During the "Process Control Self Check", depending on the ID sensor characteristics, the OPC Drum, and
other related parts, determines how Vmin is detected. The Development Gamma is calculated high. The
high Development Gamma increases the Vcnt compensation value, so after each "Process Control Self
Check", the image density decreases.
SOLUTION:
Turn off the Vcnt correction system and manually input fixed Vcnt compensation value. The optimum fixed
Vcnt compensation value is 6.
PROCEDURE:
1. If you had previously adjusted Vref (SP Data Output page 1), return it to Vref0.
2. If Toner Max M/A Target (SP Adjustment page four and page 16) was adjusted previously, return it to
default (1.000), wait 5 minutes and perform the "Process Control Self Check".
Note: After all the procedures in this TSB are finished, check the copy quality and adjust Toner
Max M/A Target if necessary.
3. If the Vcnt correction by number of scans is on, turn it off.
(Open SP Adjustment page 16 and if data in No.1 is 00001, input 00000.)
4. Turn off the Vcnt correction by development gamma.
(Open SP Special Feature page 1 and turn off the TC Correction.)
5. Manually input Vcnt compensation value. The data to input is Vcnt data at Developer Initial Setting
minus six.
Open SP Data Output page 1 and record Vcnt0 for each color. Open SP Adjustment page12 and input
Vcnt0 – six for each color into the Toner Sensor Gain data.
RICOH GROUP COMPANIES
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