AR-285 (serv.man16). AR280 285 335 Service Manual-Operational Description - Sharp Copying Equipment Service Manual (repair manual). Page 3

The operations of the image forming section are corrected in order to maintain stable and high-quality print even though any changes occur in the
temperature, humidity, consumable parts characteristics, engine conditions, or other environmental conditions.

In concrete, the correction is performed by controlling various control parameters related to the image forming section (process) operations. 

With the above correction operations, stable print quality is always provided, reducing service calls and service works. 

There are following items of the image forming section correction operations (process correction operations).

Image forming section correction operations (process correction operations) list

Item No.

Correction operations

Purpose, effect

Execution conditions, operating timing

1

Image density sensor sensitivity
correction (Calibration) (Gain
adjustment)

Allows the image density sensor to always
detect the correct image patch density. 

Before process correction operation

2

OPC drum marking sensor sensitivity
correction

Allows the OPC drum marking sensor to
always detect the OPC drum marking
normally.

 1

3

Developing bias voltage correction

Prevents against density change and
background copy.

 1

4

Laser beam power correction 1

Prevent against a decrease in print density
due to OPC drum membrane decrease.

Specified rotating time of the OPC drum
(Every 20,000 sec)

Laser beam power correction 2

Outputs the laser beam power
corresponding to the main charger grid
voltage (to maintain the constant voltage). 

Immediately after correction of the main
charger grid voltage (

1)

5

Main charger grid voltage correction 1

Corrects a decrease in the charging voltage
due to the OPC drum membrane decrease,
maintains the correct density of print and
prevent against background copy.

Specified rotating time of the OPC drum
(Every 20,000 sec)

Main charger grid voltage correction 2

Maintains the relations between the
developing bias voltage and the main
charger grid voltage at constant (to prevent
against background copy).

Immediately after correction of the
developing bias voltage (

1)

6

Toner concentration correction

Maintains the normal toner concentration to
maintain the proper density of print and
prevent against background copy.

When the developing bias voltage correction
is performed for the voltage higher than the
specified level is made immediately after the
developing bias voltage correction. (

1)

 1 During warm-up after turning on the power.

During warm-up after cancelling SIM 7-1, 24-7, 25-2, 44-2.
After completion of printing when the accumulated print time reaches 30 min from the previous correction.
When the next print is made when non-print status continues one hour.

The image forming section correction operation (process correction operation) is performed under the following conditions and timing. 

1) During warm-up after turning on the power.

2) During warm-up after cancelling SIM 7-1, 24-7, 25-2, 44-2.

3) After completion of printing when the accumulated print time reaches 30 min from the previous correction.

4) When the next print is made when non-print status continues one hour.

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