Sharp AR-280 Service Manual page 184

(6) Main charger grid voltage correction 2
a. Outline and purpose
When the developing bias voltage is changed, the main charger grid
voltage correction 2 is performed to maintain the relation between the
developing bias voltage and the main charger grid voltage at con-
stant.
b. Details
After the developing bias voltage correction, the voltage of correction
of the developing bias voltage is automatically added to the main
charger grid voltage.
Actual main charger grid voltage variable range: –200 to –900V
(7) Laser beam power correction 2
To maintain the OPC drum bright potential at constant for changes in
the main charger grid voltage due to main charger grid voltage correc-
tion 1 and 2, the laser beam power must be changed accordingly.
Laser beam power correction 2 is performed to output the laser beam
power according to the above situation.
This correction provides stable print density.
(8) Toner concentration correction A
a. Outline and purpose
This correction is used to correct changes in the developer charac-
teristics due to aging and change in the environmental conditions.
When any change occurs in the developer characteristics, it causes
under-toner or over-toner, resulting in improper print density.
To prevent against this, the reference toner control level is changed
according to the conditions to maintain the specified toner concentra-
tion.
This correction provides stable print density.
b. Details of operation
When the developing bias correction voltage (v Vdbc(n)) is minus-
corrected (shifted to the positive polarity direction), it is recognized as
an increase in developing capability, and the reference toner concen-
tration control level set with SIM 25-2 is increased.
With the above operation, toner concentration is decreased to main-
tain the proper print density.
The correction data is cleared to "0" when SIM 25-2 is executed.
Toner
concentration
control level
1
Original
reference
toner
5
concentration
control level
(Set by
SIM 25-2)
99
Operated process(DV bias correction) correction
7/13/2000
(9) Toner concentration correction B
a. Outline and purpose
Developer shows an inclination of overtoning with age. To prevent
against this, the reference toner concentration control level is
changed according to the situation to maintain the specified toner
concentration level.
b. Details of operation
When the developer rotation time (SIM 44-9: DEVE MIXING TIME)
reaches A x 1000sec, the reference toner concentration level set with
SIM 25-2 is increased by D count.
After that, correction by D count is made for every B x 1000sec, and
correction is ended up with C times of the number of times of correc-
tion.
The correction quantity can be changed with SIM 25-8. When ship-
ping, correction is not used.
<Means>
The accumulated use time of developer is detected. When it reaches
the specified level, the toner concentration control reference value is
corrected (SIM 80-2).
Toner
concentration
control level
Toner
concentration
reference value
(SIM 80-2)
·
This correction can be performed with SIM 25-8.
·
The accumulated use time of developer is detected and displayed
on the menu of SIM 44-9 similarly with the drum counter.
·
The accumulated use time of developer is cleared after execution
of SIM 25-2, and the counter is reset to 0sec. It, however, is not
cleared with SIM 25-1.
·
The accumulated use time of developer can be reset with SIM
24-11.
MAX 20
·
The current correction quantity of toner concentration reference
value is displayed on the menu of SIM 44-9 separately from toner
concentration control correction A.
·
The first correction time A can be set with a simulation and the
default is 200. (Set range: 0 to 500)
·
The second or later correction time B can be set with a simulation
T(time)
and the default is 50. (Set range: 0 to 300)
·
The number of times of correction, C, can be set with a simulation
and the default is 3. (Set range: 0 to 10)
·
The correction quantity D can be set with a simulation and the
default is 0. (Set range: 0 to 30)
10 – 4
Ax1000sec Bx1000sec Bx1000sec
Accumulated use time of developer
D count
D count
D count