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MX-DE28 N  OPERATIONAL DESCRIPTIONS  4 – 6

The paper feeder detects the amount of paper remaining in the tray as one of four levels, and displays the level it has detected. 

The paper feeder determines the remaining paper level based on how many times the paper level detector turns ON during the time between
the start of the lift-up of the paper feed tray and the activation (turning ON) of the upper limit detector. 

Paper empty detector detects 

when there is no paper remaining.

1/3 range

Sensor: logical Low

2/3 range

Sensor: logical High

3/3 range

Sensor: logical Low

When there is no paper

Paper level 1/3 position

Paper level 2/3 position

Paper level 3/3 position

Rotary panel

Paper empty detector

(CPED2, D1PED, D2PED)

Actuator for detecting the 

amount of remaining paper

Paper level detector

(CSPD2, D1PQD, D2PQD)

MX-DE28 N  OPERATIONAL DESCRIPTIONS  4 – 7

When the upper limit detector is ON and the tray is lifted up,

The amount of the remaining paper in the tray is 0% (no paper) when the paper level detector detects the empty of the paper.

The amount of the remaining paper is determined in three stages by changing the paper level detector position as the following table and figure

shown until the upper limit detector is ON after the tray is inserted and lifted up when the paper level detector detects the paper. 

The paper feeder determines the remaining paper level based on how many times the paper level detector turns ON during the time between
the start of the lift-up of the paper feed tray and the activation (turning ON) of the upper limit detector. 

Left tray(Tray 3)

Right tray(Tray 4)

0%

0%

Paper empty detector ON (No paper)

6%

9%

Paper level detector -> Transparent -> Light block -> Transparent 

Refer to the following Figure 1.

33%

50%

Paper level detector -> Transparent -> Light block

Refer to the following Figure 2.

100%

100%

Paper level detector -> Transparent 

Refer to the following Figure 3.

Lift up 

Lift up 

Paper empty detector

(D1PED,D2PED)

<Figure 1> 

<Figure 2>  

<Figure 3> 

Upper limit detector

(D1LUD, D2LUD)

Paper level detector

(D1PQD, D2PQD)

(Transparent) Low

Paper level detector

(D1PQD, D2PQD)

(Transparent) High

Paper level detector

(D1PQD, D2PQD)

(Light block) High

Paper level detector

(D1PQD, D2PQD)

(Transparent) Low

Paper empty detector

(D1PED,D2PED)

Upper limit detector

(D1LUD, D2LUD)

Paper level detector

(D1PQD, D2PQD)

(Light block) High

Paper level detector

(D1PQD, D2PQD)

(Transparent) Low

Lift up is stopped

Lift up is stopped 

Paper empty detector

(D1PED,D2PED)

Upper limit detector

(D1LUD, D2LUD)

Paper level detector

(D1PQD, D2PQD)

(Transparent) Low

Lift up is stopped 

MX-DE28 N  ELECTRICAL SECTION  5 – 1

MX-DE28 N

Service Manual

 

A

A

B

B

C

C

D

D

E

E

4

4

3

3

2

2

1

1

AC N

AC L

L 

CAL

 

CA

N 

CAN

 

CA

/RxD_LCC

/TxD_LCC

/DSR_LCC

/TRC_LCC

/DTR_LCC

RES_LCC

+2

4V

+5

V

+5

V

+24V

1/21/21/2

+24V

+24V

+24V

GND

+5V

+5V

+5V

+5V

+5V

3

LCC

2

C2PFC

C2PUC

C2LUM

Paper feed tray 2  transport clutch

Paper feed tray 2  paper feed clutch

Paper feed tray 2  lift-up motor

C2SS3

C2SS4

C2SS2

C2SSSET_D

C2SS1

2CS size detection  PWB UN

Paper feed tray 2  attachment detection detector

Paper feed tray 2  paper rear edge detector 1

Paper feed tray 2  paper rear edge detector 2

Paper feed tray 2  paper rear edge detector 3

Paper feed tray 2  paper rear edge detector 4

C2SPD

DSW_C2

C2PFD

C2PED

C2LUD

Paper feed tray 2  paper level detector

Paper feed tray 2 open/close  detection detector

Paper feed tray 2  paper transport  detector

Paper feed tray 2  paper empty detector

Paper feed tray 2  upper limit detector

WH-CS2 Dehumidifying heater (Upper)

Saf

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rounding

Saf

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rounding

Main unit

MX-DE28 N  ELECTRICAL SECTION  5 – 2

A

A

B

B

C

C

D

D

E

E

4

4

3

3

2

2

1

1

/DPFM-CLK

/DPFM-EN

DPFM-T

/DTR_DSK

/RxD_DSK

RES_DSK

/TRC_DSK

/DSR_DSK

/TxD_DSK

AC N

AC L

AC N

AC L

+5

V

+2

4V

2/22/22/2

DPFM

+24V

TANDEM MAIN PWB

CPU(ATSAMD20J16A-AU)

DPTRC

+24V

D1PFC

+24V

+24V

D2PFC

D1LM

+24V

+24V

D2LM

3

Xtal(12.288MHz)

WH-DSK

WH-DSK2

D1PFD

+5V

+5V

D1PPD1

Paper feed tray 4  paper pass detector

Paper feed tray 3  paper pass detector 1

D1PPD2

+5V

Paper feed tray 3  paper pass detector 2

D1LUD

+5V

D2LUD

+5V

Paper feed tray 3  upper limit detector

Paper feed tray 4  upper limit detector

D1PED

+5V

D2PED

+5V

Paper feed tray 3  paper empty detector

Paper feed tray 4  paper empty detector

D1PQD

+5V

D2PQD

+5V

Paper feed tray 3  paper quantity detector

Paper feed tray 4  paper quantity detector

+5V

DHOD

+5V

D1CDT

Horizontal transport  open/close detector

Paper feed tray 3  installation detector

(ULN2003AFWG)

+5V

D2CDT

Paper feed tray 4  installation detector

Desk paper feed motor

Desk paper transport clutch

Paper feed tray 3  paper feed clutch

Paper feed tray 2  transport clutch

Paper feed tray  3 lift-up motor

Paper feed tray 4  lift-up motor

Transistor array 

Sensor input  circuit

Lift motor  drive circuit

Lift motor  drive circuit

Output buffer

Output buffer

Input buffer

Input buffer

Input buffer

Input buffer

Output buffer

Warm heater(Lower1) 

Warm heater(Lower2) 

Saf

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rounding

On board writing circuit

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