Primary/Transfer Corona Current And Grid Bias Voltage Control System; Outline; Switching Primary/Transfer Corona Current On/Off - Canon NP6320 Service Manual

III. PRIMARY/TRANSFER CORONA CURRENT AND
GRID BIAS VOLTAGE CONTROL SYSTEM
A.

Outline

The circuit shown in Figure 4-301 controls the primary/transfer coronal current and the bias
voltage of the grid of the primary corona. Main functions are as follows.

1. Switching primary/transfer corona current ON/OFF

2. Maintaining primary/transfer corona current constant
3. Switching primary corona grid bias voltage
4. Switching primary corona grid bias ON/OFF
In order to eliminate the effects of changes in atmospheric conditions on the effectiveness of
the corona discharge, the current to the primary corona wire is maintained constant.
The primary corona and transfer corona current are switched ON and OFF by the HVT ON
command (HVTON*).
The grid bias voltage is switched by the GRID ON signal (GRDON).
B.

Switching Primary/Transfer Corona Current ON/OFF

a. When HVTON*=1
Differential amplifier goes OFF.
Variable pulse width oscillator goes OFF.
High-voltage transformer goes OFF.
b. When HVTON*=0
Differential amplifier goes ON.
Variable pulse width oscillator goes ON.
High-voltage transformer goes ON.
COPYRIGHT © 1999 CANON INC.
CHAPTER 4 IMAGE FORMATION SYSTEM
CANON NP6320 REV.0 DEC. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
4-5