AR-FN3 (serv.man2). ARFN3-Service Manual - Sharp Copying Equipment Service Manual (repair manual). Page 45

The control signal (STMA,B) from the expansion I/O expansion is
inputted through the driver TD62503F to the H driver circuit which
consists of a large-current driving transistors Q1 

∼

 4, thus driving the

staple motor which staples sheets.

The rotational direction (CW, CCW) of the staple motor is controlled
by signal logics STMA, STMB. The motor is braked to a stop at the
home position.

TD62503 (IC105) is a driver to drive Q1 

∼

 4. A delay circuit is com-

posed of peripheral resistors, capacitors, and diodes to prevent short
current from flowing into the H driver circuit which is formed by Q1 

∼

4, when STMA and STMB are changed over.

The staple motor has a large rush current. It thus has a current limit
circuit consisting of a voltage comparator BA10393F (IC104) and
peripheral resistances and capacitors, to apply current limit at about
5.3A.  To prevent the circuit from shorting or motor locking, a protec-
tive fuse (F2) is installed.

The stapler unit (EH-524S: Max Co., Ltd.) staples up to 50 sheets of
80g/m

2

 paper. The unit consists of a driving DC motor (STM), home

position sensor (STHP), non-needle sensor (LSTS), cartridge sensor
(NCTS), and self-priming sensor which detects the stapling position of
needles (READY).

Item

Specification

Outside dimensions

97(H) 

×

 80(W) 

×

 104(L) mm

Stapling capacity

52 g/m

2

 sheets ~ 80 g /m

2

 50 sheets,

below 5 mm thick

Stapling type

Bypass flat clinch

Stapling speed

400 msec or below

Needle cartridge

5000 needles

500

3K

2SB1431

Q04

150

5K

2SD1590

Q03

2.5A/125V
T1.6A/250V

F02

+24V

I/O

PE4

PE5

8 STMA

9 STMB

+5V

R168

R167

R165

R166

D08

D07

RN105

10K

10K

200

200

1K

1K

1SS133

1SS133

(IC03)

TD62503F

TD62503F

3

14

4

13

IC105

IC105

R176

C179

68000P

1K

IC105

IC105

TD62503F

TD62503F

15

2

1

16

R22

R23

2.4K(1/4W)

2.4K(1/4W)

R175

C180

68000P

C163

10000P

C164

10000P

500

3K

2SB1431

Q02

150

5K

2SD1590

Q01

D03 D04

STM+

STM-

STM

1SR124-400

2

1K

+5V

R138

+
-

100

C151
0.1U

C152
0.1U

R151
1.2K

R7

0.22
(1W)

R152
3.9K

+5V

+10V

+5V

R153
2.2K

BA10393F

C178
0.1U

8

1

3

2

4

IC104

5

12

11

6

TD62503F

TD62503F

IC105

  

RN105

STHP

STM

LSTS

NCTS

READY

+5V

GND

Finisher

main PWB

Stapler unit

AR-FN3

9 – 12

8/19/1999