Transition Of Photoconductor Surface Potential; Photoconductor Drum Sensitivity Correction; Process Control Function - Sharp SF-2220 Service Manual

(4) Transition of photoconductor surface potential

Charge
-730V
-215V

(5) Photoconductor drum sensitivity correction

In this model, fall in sensitivity due to long use of the photoconductor
drum is corrected by the copy lamp light intensity to prevent against
considerable change in copy quality.
The photoconductor drum sensitivity fall correction is performed as
follows:
Cleaner
OPC drum
CLV + 2 counts
(Sim46)

(6) Process control function

[Summary]
The process control function detects the density of the standard toner
image formed on the photoconductor, the density of the initial image
and controls the charging grid voltage so that the same level as the
initial image density is provided.
That is, the process conditions are established and the high voltage
output and exposure level are controlled to stabilize the toner density.
In this model, the density sensing level is automatically set.
Develop
Exposure BL
Dark area
Developing bias voltage
Light area
Develop
Change the tickness of the carrier transport layer (CTL).
By the developper.
By the cleaner blade.
CLV
CL(V) + (0.33V x 2)
Sim46
Transfer Separate
Residual potential
(NEW)
CTL
CGL
0 5K 10K 15K
R
MAin control PWB
CPU density
judgement
I/O MC grid
output selection
5 – 14
Clean D L
(USED)
CTL
CGL
20K 25K 70K 75K
Drum counter
F
High voltage PWB
MC grid bias
output (density
correction)
in each mode
(Light quantity
correction)
80K