Mita-Kyocera ST20 CHAPTER3

Chapter 3

Paper specifications

Chapter 3 Contents

3-1 Introduction ...................................................................................................................................... 3-3

3-2 Power supply/motor driver board .................................................................................................. 3-4

3-2-1 Power supply circuit........................................................................................................................ 3-4

3-2-2 Motor driver circuit .......................................................................................................................... 3-5

3-3 Controller board............................................................................................................................... 3-6

3-3-1 Solenoid driver................................................................................................................................ 3-7

3- 4 Printer interface .............................................................................................................................. 3-8

3-4-1 Connector configuration.................................................................................................................. 3-8

3-4-2 Controller board CPU I/O interface................................................................................................. 3-9

3-5 Sensors........................................................................................................................................... 3-11

3-6 Error message................................................................................................................................ 3-12

3-7 Printing timing charts.................................................................................................................... 3-13

3-1 Introduction

This chapter explains the operation of the electrical circuits in the bulk stacker. Procedures for
hardware troubleshooting are also included in this chapter. Schematic diagrams are provided in
Appendix. The schematic diagram should be referred to along with the explanation in the following
pages.

The electrical system of the bulk stacker can be functionally divided in the following two parts:

Power supply/motor driver
Controller

These two part are mounted on separate circuit-boards. Details on each part follow are explained
on the following pages.

3-3

ST-20

3-2 Power supply/motor driver board

See figure 3-2-1 below. The motor driver/power supply board is located on the top of the bulk
stacker, inside the top plate.

Power supply/motor driver board

Figure 3-2-1 Location of power supply/motor driver board

3-2-1 Power supply circuit

See appendix power supply/motor driver board circuit diagram.

The bulk stacker has no power switch provided as the printer's power switch simultaneously activates
the bulk stacker's power supply. When printer power turns on, the 5 V DC reaches at pin #3 of the
interface connector. It activates and closes relay RL1 on the motor driver/power supply board
which in turn connects the primary power (120 or 220 V AC) to transformer T1. The power supply
section produces both the 5 V and 24 V DC and feeds them accordingly to the respective circuits.
Regulator IC1 is provided for the 5 V DC power supply.

ST-20

3-4

3-2-2 Motor driver circuit

See appendix power supply/motor driver circuit board diagram.

The motor driver receives commands for driving the feed motor from the controller board through
connector J1.

The feed motor is located on the top of the bulk stacker, inside the top panel. The feed motor drives
the feed roller for feeding paper arriving from the printer towards the paper tray. Power voltage for
this motor is regulated by means of resistors R11 and R14 on the power supply/motor driver board
so as to obtain a constant 16 V DC source. The feed motor turns on when the level of pin #9 of J1
(FEEDON*) becomes low.

3-5

ST-20

3-3 Controller board

The controller board is located on the right inside of the bulk stacker as shown in figure 3-3-1
below.

Controller board

Figure 3-3-1 Location of the controller board

A 4-bit CPU (µPD75004) is used in the controller board to manage controlling the following devices,
while keeping contact with the printer using the serial communication method.

Solenoid driver
Printer interface
Sensor controller

Details on each of these devices follow.

ST-20

3-6

3-3-1 Solenoid driver

The bulk stacker has one solenoid (Duplexer selection solenoid). Solenoid is located as shown in
Figure 3-3-2 below and changes the paper path according to the simultaneous activation of the
duplexer (DU-20/DU-21).

See figure 3-3-3, If the bulk stacker is used together with the duplexer for duplex printing, the CPU
IC1 turns the DPSON* signal low , which in turn ener gizes duplexer selection solenoid to allow the
paper to be fed into the duplexer.

Duplexer selection solenoid

Figure 3-3-2 Duplexer selection solenoid

24 V DC

CPU

IC1

37

14

Driver

IC3

15

DPSON*

Figure 3-3-3 Solenoid control signal

3-7

Duplexer
selection
solenoid

ST-20

3- 4 Printer interface

This section provides information regarding the bulk stacker's interface to the printer.

3-4-1 Connector configuration

The bulk stacker and the printer exchange signals between each other through connector J7 which
is mounted on top the bulk stacker . The names and the functions of the signals handled by the bulk
stacker are as follows.

5 4 3 2 1

6 7 8 9 10

Bulk stacker's left side

Printer positioning pin

Figure 3-4-1 Bulk stacker connector

Table 3-4-1 Bulk stacker connector pin assignment

Pin No. Input/Output Signal Description

1 Input DSENS Duplexer’s feed path sensor (open collector) output

(24 V DC if duplexer is installed above the bulk

stacker)
2 Input SCKD Serial clock
3 Input +5 V 5 V DC power
4 Output READY Hand shake signal
5 Input SEL0 Select bit 0
6 Input SEL1 Select bit 1
7 Input SEL2 Select bit 2
8 Output SID Bulk stacker output data
9 Input SOD Bulk stacker input data
10 - GND Ground

ST-20

3-8

Signals SEL0, SEL1, and SEL2 are used by the printer to select and deselect the bulk stacker. The
bulk stacker is selected as the paper destination when SEL0 is “1”, SEL1 is “0”, and SEL2 is “1”.

All levels are of C-MOS level. Pulled-up for input and open-circuited for output. The clock­synchronous serial interface configuration is used with the maximum synchronization clock of 200
kHz.

3-4-2 Controller board CPU I/O interface

Table 3-1 below shows signals used by the controller board CPU (µPD75004) for its I/O interface.

Table 3-4-2 Controller board CPU I/O signals

Pin Input/Output Signal Description Logic (Meaning)

12

-

SOD(SI)

Printer's communication

­14
18, 19
17
25
24

22, 23
31
32
33
27-29
10, 11

13
9
40, 41
39

-

­Input
Input
Input

-

­Input

-

-

-

-

­Output

­Output

SCKD*

­RCOPN*
DSENS
SOIN*

-

­NSBF*

­SEL0-SEL2
DIPSW1-DIPSW2

SID (SO)
READY*

­FEEDON*

Communication clock
Not used
Rear cover status
Paper feeding in duplexer
Paper detection in bulk stacker's
paper inlet
Not used
Not used
Paper full in paper tray
Not used
Bulk stacker activation bits
Bulk stacker mode selection bits;
“1” for both bits (at power on)
Status to printer (communication)
Ready to send status
Not used
Feed motor status

-

Cover open
No paper
Paper detected

-

-

Paper full

-

-

-

-

-

Ready

-

On

On
38
37
34-36
6, 7

Output
Output

-

-

RDYLED*
DPSON*

-

-

READY indicator status
Path selection/duplexer
Not used
Not used

3-9

To duplexer

-

-

-

ST-20

The following table shows port assignment for the controller board CPU (µPD75004).

Table 3-4-3 Controller board CPU pin assignment

Port bit3 bit2 bit1 bit0

Port0
Port1
Port2
Port3
Port4
Port5
Port6
Port7
Port8

SI

-

-

­RDYLED*

-

-

-

-

SO
RCOPN*
NSIN*
VLOW*
FEEDON*

-

­SEL2

-

SCK

­SOIN*

-

-

­NSBF*
SEL1
DIPSW2

-

­DSENS*
READY*

­DPSON*

­SEL0
DIPSW1

ST-20

3-10

3-5 Sensors

The bulk stacker has sensors provided for controlling paper transportation and detection of paper
jam. The following sensors are used:

Table 3-5-1 Controller board CPU input sensors signals

Sensor Signal Function Type of sensor Logic

Inlet sensor

Paper tray
exit sensor

Paper tray
full sensor

SOIN*

NSIN*

NSBF*

Mounted at the paper inlet of
the bulk stacker. Detects the
paper fed and occurrence of
paper jam; provides various
timings for bulk stacker
control.

Located at the paper tray exit.
Detects timing of paper exit
and occurrence of paper jam.

Detects if the paper tray
becomes full (approximately
1500 sheets).

Photo
interrupter

Photo
interrupter

Photo
interrupter

Pin #24 of CPU
IC1 turns to low
while paper is
sensed.

Pin #23 of CPU
IC1 turns to low if
paper exists.

Pin #32 of CPU
IC1 becomes low
when the paper
tray is full.

3-11

ST-20

3-6 Error message

The printer looks after itself and shows various error codes starting with the Call Service person
message if a defect is found during operation. The error messages pertaining to use of the bulk
stacker together with the printer are as follows.

Table 3-6-1 Error codes regarding bulk stacker

Error code Meaning Suggested remedy

C4

C5

C6

For other error codes, refer to printer's Service Manual.

Defect in communication between the
bulk stacker and the printer engine.

Error during self-diagnostics of bulk
stacker.

Defect at power-up in communication
between the bulk stacker and the
printer engine.

Replace the printer’s engine
board. Replace the bulk
stacker’s controller board.
Replace the connector of bulk
stacker.

Replace the bulk stacker’s
feed motor. Replace the bulk
stacker’s power supply/motor
driver board.

Replace the printer’s engine
board. Replace the bulk
stacker’s controller board.
Replace the connector of bulk
stacker.

ST-20

3-12

3-7 Printing timing charts

FS-3700/ST-20/A4

3-13

FS-3700 Motor
(MMOT)

FS-3700 Cassette feed
(FDCL1)

FS-3700 Registration clutch
(REGCL)

FS-3700 Registration sensor
(JAMR)

FS-3700 Fuser sensor
(JAM0)

HS-20 Motor
(MON, VLOW)

HS-20 Sensor
(HSPAP)

ST-20 Feed motor
(FEED)

ST-20 Inlet sensor
(SOIN)

ST-20 Paper tray exit sensor
(NSIN)

0 (s)

1055 (ms)

1055

24

2454

2012

2620

2243

High speed

2621

4311

5163

4117

Low speed

4697

5382

5495

6

5706

5872

5918

6754

6798

6899

810

8413

7369

7948

7500

9170

7807

7748

8532

10011

10055

9170

9194

10154

12 14

11842

11842

10760

12445

11070

11010

11800

ST-20

ST-20

FS-3700/DU-20/ST-20/A4 (Continued to next page)

3-14

FS-3700 Motor (MMOT)
FS-3700 Cassette feed

(FDCL1)
FS-3700 Registration clutch

(REGCL)
FS-3700 Registration sensor

(JAMR)
FS-3700 Fuser sensor (JAMO)

HS-20 Motor (MON, VLOW)

HS-20 Sensor (HSPAP)

DU-20 Motor
(FEED0, FEED1, VLOW)

DU-20 Clutch (CLON)
DU-20 Stepping motor

(PA, PB, PA_, PB_)
DU-20 Entrance sensor (PISNS)

DU-20 Home sensor (PHSNS)
DU-20 Exit sensor (POSNS)

DU-20 Guide home sensor
(GHOME)

ST-20 Feed motor (FEEDON)

ST-20 DU-1/ST-20 (DPSON)

ST-20 Inlet sensor (SOIN)

ST-20 Paper tray exit sensor
(NSIN)

0 (s)

4

4500

5456

5702

4500

High speed

6068

6

6914

6082

5982
FWD.

High speed

6218

CCW

6178

6218

810

9022

9978

8626

7576

8160

Low speed

9378 17020

10432

10216

10218

10266
High speed

10488

12 14 16 18 20 22 24 26

11130

11716

12412

13437

13587

CW

13724

REV.
Low speed

15166

15218

15166

15360

16492

16268

15800

FWD.
High speed

16936

16936

16100

16498

16748

17104

16812

17850

17706

17106

16788
CCW

16788

18800

18612

18172

FWD.,REV.

18180

18180

1826416630

19660

19182

18908

19488

19532

19524

20206

19870

19992

20408

21211

20186

20374

21248

21296

21361

CW

21754

21870

22042

21816

21816

23288

22008

23398

22608

22920

22450

22750

22706

22668

23140

23460

23672

23586

23586

23438

CCW

23146

23438

23408

23750

24500

24826

23758

23758

24050

25450

25264

25834

24832

24832

24936

FS-3700 Motor (MMOT)

FS-3700 Cassette feed
(FDCL1)

FS-3700 Registration clutch
(REGCL)

FS-3700 Registration sensor
(JAMR)

FS-3700 Fuser sensor (JAMO)

22 (s)

22920

23140

23460

24

23758

24508

25450

25264

26

26522

26312

26854

27024

26642

27900

28 30

29788

Repeat

29566

28522

30398

30108

31156

32 44 36 38

36332

36624

36330

31904

32954

34544

28310

39178

40

42 44 46 48

FS-3700/DU-20/ST-20/A4 (Continued)

43941

40768

3-15

ST-20

HS-20 Motor (MON, VLOW)

HS-20 Sensor (HSPAP)

DU-20 Motor
(FEED0, FEED1, VLOW)

DU-20 Clutch (CLON)
DU-20 Stepping motor

(PA, PB, PA_, PB_)
DU-20 Entrance sensor (PISNS)
DU-20 Home sensor (PHSNS)

DU-20 Exit sensor (POSNS)
DU-20 Guide home sensor

(GHOME)

ST-20 Feed motor (FEEDON)

ST-20 DU-1/ST-20 (DPSON)

ST-20 Inlet sensor (SOIN)
ST-20 Paper tray exit sensor

(NSIN)

22450

22042

22008

23146

22608

23586

23586

23288

23398

22706

22668

23672

23758

23758
23438

CCW

22750

23438

23408

24826

24050

25834

25562

24832

24832

24936

26164

26836

26206

26198 29386

30320

30230

30230

30082

CCW

30082

30096

30398

30398

30740

31466

31476

31476

31612

32476

32206

32846

33482

32888

32880

27944

27060

27861

CW CW

28462

28011

28658

28436

29098

28706

28462

29932

29400

29796
30042

39350

29288

34590

34688

34688

34507

34657

34870

35116

3535633700

35622

35978

36454

36454

36016

36042

36624

36624

37430

36788

37700

37700

37454

38702

38066

39926

40812

41580

41336

42264

42200

42596

47576

43560

43684

43018