Specifications

6.6.2 Vd Correction Factor (Only For Black Toner)

After developer is replaced, the triboelectric charge sometimes changes as

the new developer mixture is not stabilized in during the first 500 copies. The

development bias for the ID sensor is adjusted automatically to compensate

for these changes.

The CPU calculates the threshold level for the Vd correction when the black

developer initial setting procedure (SP mode #65) is completed. This

threshold level is the average of Vsp/Vsg x 100 (%). The result of the

calculation can be monitored by SP mode #64. The CPU has a software

counter to count number of copies made with the developer. The counter

resets to "0" when SP mode #65 is performed. The Vd correction is made

based on the data of the counter and of SP mode #64. The following table

gives the threshold levels for each data value of SP#64.

SP Data

(SP mode #64)

Vsp/Vsg x100 (%)

Change of Development Bias Voltage

0 to 499 copies More than 500 copies

12 to 15

0 to 7

8 to 11

16 to 21

More than 22

±0 volts

–40 volts

–20 volts

±0 volts

+20 volts

+40 volts

1 December 1990

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