Sharp SF-1120, SF-1020 service manual Optical system dirt correction, Cpu

(Optical system dirt correction)

This model perform dirt correction by changing the copy lamp inten- sity according to the dirt degree in the optical system (the copy lamp unit, No. 1 mirror, No.2 mirror, No.3 mirror) to prevent against remark- able degrading of copy quality.

The reference value is the AE sensor output value which is obtained when the reference plate is exposed with the copy lamp voltage of 67.0V (134.0V) at power ON.

This value is checked with sim 44-08, 09.

Reference plate (Glass holder) Table glass

Copy lamp light quantity "UP"

Automatic exposure sensor

CPU

Reference value >Measured value Correction data output

CLV
Sim46
CL(V) = INI CL(V) + (0.33 x 2)
1step = (0.33 x 2)
100	200	300	400
CLV + (0.7)

(1) Setting the reference value for optical system correction.		(2) Dirt correction
Reference plate (Glass holder)	Table glass	Reference plate (Glass holder)

79.8K 80K

Table glass

Automatic exposure sensor

CPU reference value setting

1Clean the optical system at every maintenance.

2Perform Simulation 46-1.

(The previous data are cleared.)

3After completion of Simulation 46-1, when performing the first mirror initialization, measure light quantity of the copy lamp. Obtain the average value from the four measurement values and use the average value as the reference value for correction.

800ms

CL

Light quantity measurement

Obtain the average value of four AE sensor values, and store it.

Copy lamp light quantity "UP"

Automatic exposure sensor

CPU

Reference value >Measured value Correction data output

1Measure light quantity when performing mirror initialization.

2Store the correction data into memory.

3Reset the register inside the CPU.

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