CHAPTER 2 THEORY OF OPERATION
Confidential
2-20
When the new toner detection switch detects that the toner cartridge is replaced with a new
one, the developing bias voltage is initialized at the same time.
The toner used for the printer has a property that print density is light first and gradually darker
in the course of usage. The developing bias controls the toner property so that the print
density is constant from first to last.
Toner property
Actual control
[Used toner amount]
[Used toner amount]
Print density
Bias voltage
Bias voltage
Print density
[Density]
[Voltage]
[Density]
[Voltage]
To obtain a print result of a constant density all the time, the printer counts the number of print
pages immediately after the toner cartridge is replaced and changes the bias voltage according
to the accumulated number of prints with the toner cartridge.
The bias voltage is changed with the steps described below:
(1) When the new toner sensor detects that the toner cartridge is replaced with a new (full)
one, the developing bias is set to 400V (initialized).
(2) After that, the bias voltage is stepped down according to the number of prints.
3.4.3 Counter reset during indication of “Toner Life End”
The counter resetting method during indication of “Toner Life End” depends on the cause of
toner life end and the condition of the inserted toner cartridge. Refer to the following table for
details.
Toner Life End
(Toner empty)
Toner Life End
(Developer count full)
When a used toner is
inserted (Reset gear
is at the position of in
use.)
Toner exchange count: +0
Page counter of each toner: Continued
Coverage of each toner: Continued
Development bias: Reset (Default)
Not used.
When a new toner is
inserted (Reset gear
is at the position of
factory set.)
Toner exchange count: +1
Page counter of each toner: Reset (0)
Coverage of each toner: Reset (0)
Development bias: Reset (Default)
