AR-C150 (serv.man5). ARC150-Basic Manual - Sharp Copying Equipment Service Manual (repair manual). Page 55

a. Outline and purpose
When the developing bias voltage is changed, the main charger grid voltage is corrected in order to maintain the constant difference (voltage differ-
ence of 200V) between the bias voltage and the main charger grid voltage to prevent against background copy. 
When the developing bias voltage is changed, this correction is performed automatically. 

b. Details of operation
If the main charger grid voltage is not –200V higher than the developing bias voltage, background copy is made. 

After correction of the developing bias voltage, the main charger grid voltage is automatically added with the correction quantity of the developing bias
voltage.
Therefore, the actual main charger grid voltage becomes as follows:

Correction is performed for the following three ffactors by changing the transfer voltage.

1) Correction for changes in the transfer capability due to changes in temperature and humidity. 

2) Correction for changes in the transfer efficiency due to the paper kind. 

3) Correction for changes in the transfer efficiency due to changes in the paper surface conditions.

The transfer voltage is changed according to the above conditions. 

TRANSFER VOLTAGE CORRECTION TABLE

(PRINT MODE)

Condition

level

Humidity

sensor

count value

Normal paper(Simplex)

Cardbord

Transparency sheet

Normal paper(Duplex)

K

C

M

Y

K

C

M

Y

K

C

M

Y

K

C

M

Y

1

1 – 10

3KV

3KV

3KV

3KV

3KV

3KV

3KV

3KV

3KV

3.5KV

4KV 4.5KV 3KV

3KV

3KV

3KV

2

11 – 18

2.75KV 2.75KV 2.75KV 2.75KV 3KV

3KV

3KV

3KV

3KV

3.5KV

4KV 4.5KV 2.75KV 2.75KV 2.75KV 2.75KV

3

(Standard)

19 – 30

2.5KV

2.5KV

2.5KV

2.5KV

3KV

3KV

3KV

3KV

3KV

3.5KV

4KV 4.5KV 2.5KV 2.5KV

2.5KV

2.5KV

4

31 – 40

2.25KV 2.25KV 2.25KV 2.25KV 3KV

3KV

3KV

3KV

3KV

3.5KV

4KV 4.5KV 2.25KV 2.25KV 2.25KV 2.25KV

5

41 – 50

2KV

2KV

2KV

2.25KV 2.5KV 2.5KV 2.5KV 2.5KV 2.75KV 3.25KV 3.75KV 4.5KV 2KV

2KV

2KV

2.25KV

6

51 – 60

1.75

1.75

1.75

2.25KV 2KV

2KV

2KV

2KV 2.5KV

3KV

3.5KV 5KV 1.75KV 1.75KV 1.75KV 2.25KV

7

61 –

1.75

1.75

1.75

2.25KV 2KV

2KV

2KV

2KV 2.5KV

3KV

3.5KV 5KV 1.75KV 1.75KV 1.75KV 2.25KV

IMAGE DENSITY CORRECTION(PROCESS ORRECTION) MODE

Humidity

condition

level

Humidity

sensor count

value

Image density correction(Process

correction)

K

C

M

Y

1

1 – 10

3KV

3KV

3KV

3KV

2

11 – 18

2.75KV 2.75KV 2.75KV 2.75KV

3 (Standard)

19 – 30

2.5KV

2.5KV

2.5KV

2.5KV

4

31 – 40

2.5KV

2.5KV

2.5KV

2.5KV

5

41 – 50

2.5KV

2.5KV

2.5KV

2.5KV

6

51 – 60

2.25KV 2.25KV 2.25KV 2.25KV

7

61 –

2KV

2KV

2KV

2KV

CONDITION LEVEL TABLE

Condition level

Humidity sensor count value

1

1 – 10

2

11 – 18

3 (Standard)

19 – 30

4

31 – 40

5

41 – 50

6

51 – 60

7

61 –

This operation is to correct changes in the developer characteristics
due to aging and changes in the environment (temperature and hu-
midity). 
The developer characteristic (chargeability) fluctuates greatly in the
early stage, and fluctuates by changes in temperature and humidity
and by aging.
The change in the developer chargeability may lead to an error in the
toner concentration sensor operation. 
If there occurs an error in the toner concentration sensor operation,
the toner concentration cannot be controlled properly.  

The developing density is also changed by the change in the devel-
oper chargeability. 

These factors may cause undertoner, overtoner, or insufficient charg-
ing, resulting in an abnormal print density. 

To prevent against the above, the reference toner concentration con-
trol level is changed according to the situations to keep the constant
toner concentration.
This correction keeps the constant toner concentration, prevents
against toner dispersion, and stabilizes the print density. 

(Correction for aging)
Correction is performed by changing the reference toner concentra-
tion control level according to the developer correction counter (devel-
oper unit operation time). 
The developer correction counter is reset by execution of SIM 25-2.

(Correction for changes in humidity)
When the developing bias voltage is changed and the humidity rank
level s changed in the high density (saturation density) image correc-
tion, the correction is performed by changing the reference toner con-
centration control level.

AR-C150

3 – 8