Canon GP335 Service Manual page 135

6. Correcting the Application Voltage Level (APVC control)
The primary charging efficiency varies according to changes in the site environment
(temperature, humidity) and deterioration of the charging roller. A reference current is applied
when the main power switch is turned on to find out the degree of voltage output for correction a
follows:
A reference voltage is applied during initial rotation after main power switch is turned on.
The current output is measured, and communicated to the PW-CPU of the composite power
supply PCB.
The PW-CPU computes the optimum application voltage.
Primary charging is initiated using the optimum application voltage.
7. Controlling the Output Mode
To prevent stray toner in non-image areas in continuous copying, both AC bias and DC bias
outputs are varied between image areas and non-image areas.
Related Service Mode
ADJUST>HV-PR1>P-DC
ADJUST>HV-PR1>P-NO-DC
ADJUST>HV-PR1>P-AC
ADJUST>HV-PR1>P-NO-AC
Be sure to enter the value indicated on the service label if you have replaced the image
processor PCB or initialized the RAM.
COPYRIGHT © 1999 CANON INC. CANON 405/335 REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 6 IMAGE FORMATION SYSTEM
DC bias output for image areas.
DC bias output for non-image areas.
AC bias output for image areas.
AC bias output for non-image areas.
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