Canon IR2800, IR3300 Controlling the DC Developing Bias, Controlling the AC Developing Bias, 20 P

CHAPTER 4 IMAGE FORMATION SYSTEM

7.2.2 Controlling the DC Developing Bias

[1]When the DC bias ON signal from the DC controller PCB goes ‘0’, the bias control sig- nals (pulse signals) are generated by the PW-CPU of the high-vole power supply PCB.

[2]The DC bias from the high-voltage main transformer is applied to the developing cylin- der.

[3]The output voltage level of the DC bias is fed back to the PW-CPU.

[4]The pulse width of the DC control signal is varied to suit the return voltage, thereby maintaining the DC bias to a specific level.

7.2.3 Controlling the AC Developing Bias

[1]When the AC bias ON signal and the AC pulse ON signal from the DC controller PCB goes ‘0’, the AC transformer is driven.

[2]An AC bias is added to the DC bias and applied to the developing cylinder.

7.2.4 Controlling the Level of the DC Developing Bias

the level of the DC developing bias is varied between image area and non-image area to prevent stray toner inside the machine.

In memory copy mode, the laser is driven based on binary image data which lacks density information, not enabling adjustment using a density correction curve for the density of the image being generated. To make up for the lack, the DC developing bias is varied for den- sity adjustment.

E064

Indicates the presence of a high-voltage (primary charging, transfer charg- ing, development) output fault.

COPIER>ADJUST>DEVELOP>DE-DC

Use it to enter the adjustment value of the developing bias DC component for the image area.

COPIER>ADJUST>DEVELOP>DE-OFST

Use it to enter the offset value for the developing bias DC component.

4-20 P COPYRIGHT © 2001 CANON INC. CANON iR2200/iR2800/iR3300 REV.0 MAR. 2001