Sharp SF-1020 AE Auto Exposure sensor circuit, Toner supply motor drive circuit, Reset IC IC13

Models: SF-1120 SF-1020

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(9) AE (Auto Exposure) sensor circuit

The AE sensor circuit is composed of the AE sensor PWB; which is composed of the photo diode, the I-V convertor circuit, and the amplifier circuit; and the amplifier circuit on the control PWB.

 

 

 

 

 

+24V

CPU

 

 

 

 

4

 

AES

 

R40

1

 

AN0

 

 

 

 

 

 

 

1KJ

IC14A

 

 

 

 

 

 

 

C38

ZD2

LM324 11

 

 

 

1000PF

HZS883

 

 

 

 

 

 

I/O

 

AEG1

 

 

 

 

 

 

 

 

 

 

AEG0

 

 

 

 

 

R50

100KJ

2

R53

C48

0.1µ F

3

1KJ

 

6

 

 

7

 

 

5

 

 

IC14B

 

 

 

 

 

LM324

 

R44

R43

R45

R47

15KF 750F 75F 270F

AEG1

AEG0

 

PDK

 

PDA

R48

 

C49

100KJ

 

2200PF

 

AE sensor PWB

Operation amplifier A performs I-V conversion of the original density level (minute current) from the sensor. Operation amplifiers B and C amplify the output of operation amplifier A to a suitable level for inputting to the CPU.

The amplifying level is automatically set by selecting the AE gain signal (AEG0 AEG2) outputted from the I/O chip when test command SIM 47 is executed.

AE operation is performed by the software in the control PWB. When a reflected ray enters the sensor, a voltage corresponding to the light quantity is inputted to the CPU. The CPU compares the input voltage and the copy lamp application voltage and controls the copy lamp voltage so that the exposure level corresponds to the original density.

(10) Toner supply motor drive circuit

IC104 is the motor control IC which drives the toner supply motor with the pulse signals (TMa, TMb) outputted from the I/O chip.

 

 

 

 

 

 

+24V

 

 

 

 

IC5

 

C2

 

 

+5V

2

 

6

+

 

 

 

 

 

 

 

TMa

 

9

IN1

8

10UF35V

 

 

 

 

 

 

I/O

TMb

 

1

IN2

7

TMa

 

 

5

3

TMb

 

 

 

GND

 

 

 

 

 

 

 

R20

R211

 

TA7291S

 

 

 

47KJ

47KJ

 

 

 

 

M

Truth value table

 

Input

 

Output

Mode

 

 

 

 

 

 

TMa

 

TMb

TMa

 

TMb

 

 

 

 

 

 

 

 

L

 

L

 

Stop

 

 

 

 

 

 

 

H

 

L

H

 

L

CW/CCW

 

 

 

 

 

 

 

L

 

H

L

 

H

CCW/CW

 

 

 

 

 

 

 

H

 

H

L

 

L

Break

 

 

 

 

 

 

 

: High impedance Internal circuit

(11) Reset IC (IC13)

1General

The M51953 BL is the semiconductor IC most suitable to detect the power voltage and reset the logic circuit of every type including the CPU.

It is provided with the built-in delay circuit. Delay time is easily ob- tained by adding external capacity.

Pin connections (Top view)

 

5

Output

BL

4

Delay capacity

M51953

3

GND

 

 

2

NC

 

1

Power

+5V

 

+24V

 

2

8

 

 

 

 

6

+24V

 

REG

TMa

 

 

7

 

 

 

 

 

 

 

M

 

Protection

3

 

 

circuit

TMb

 

 

(Heat insulated)

 

 

 

 

9

1

5

 

 

 

GND

 

TMa

 

4 pin = NC pin

 

TMb

 

 

 

External view 5P5

12 – 14

Page 133
Image 133
Sharp SF-1020, SF-1120 AE Auto Exposure sensor circuit, Toner supply motor drive circuit, Reset IC IC13, Cw/Ccw, Ccw/Cw