Operation; Charging Control; Wire Cleaning Control; Erase Lamp Control - Konica Minolta BIZHUB 750 Service Manual

9. CHARGING SECTION
9.3

Operation

9.3.1

Charging control

A. Charge wire
The high voltage unit (HV) pressurizes 24V DC to impress a minus (-) DC voltage to the charging wire for dis-
charge.
Charging output range: -600
B. Charge grid
To make the discharge of the charging wire uniform, a minus (-) high voltage is impress from the high voltage unit
(HV) to the charging grid.
Charging grid voltage output range: -500 V to -1000 V
9.3.2

Wire cleaning control

A. Purpose
The wire is cleaned periodically to prevent the deterioration of the discharge characteristics caused by soil
adhered to the charging wire.
B. Timing
• While in the print, executes after completion of a job for every specified number of prints.
• When the environmental condition meets the prescribed condition, executes according to the predeter-
mined condition.
NOTE
• When the environmental condition meets the specified condition with the power on, no cleaning is
made.
• While in the print, the cleaning operation varies with the setting of the software DIPSW in the ser-
vice mode. For particulars, see "24. IMAGE STABILIZATION CONTROL."
9.3.3

Erase lamp control

A. Purpose
To neutralize the residual potential on the drum surface and make the potential on the drum surface uniform, the
erase lamp (EL) is illuminated on the drum before charging.
B. Timing for the erase lamp to be turned on
A start signal turns ON the erase lamp (EL), and it is turned OFF a specified period of time after the last paper is
detected by the paper leading edge sensor (PS43).
28
µ µ
A to -1200 A
Theory of Operation Ver1.0 Aug.2005