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MX-M753N  EXTERNAL VIEW AND INTERNAL STRUCTURE  4 – 20

13

Paper feed roller 
(No. 4 paper feed tray)

Feeds paper to the paper transport section.

14

Separation roller 
(No. 4 paper feed tray)

Feeds paper to the paper transport section.

15

Paper pickup roller 
(No. 4 paper feed roller)

Sends paper to the paper transport section.

16

Resist roller (Drive)

Transports paper to the transfer section. / Controls the paper transport timing and adjusts the relative relationship 
between the image and paper.

17

Resist roller (Idle)

Applies pressure to paper and the resist roller to transport the paper.

18

Transport roller 1 (Drive)

Transports paper fed from the large capacity tray (LCC) to the transport roller 2.

19

Transport roller 1 (Idle)

Applies pressure to paper and the resist roller to transport the paper.

20

Transport roller 2 (Drive)

Transports paper transported from the manual paper feed and the transport roller 1 to the transport roller 3.

21

Transport roller 2 (Idle)

Applies a pressure to paper and the transport roller to provide a transport power of the transport roller to paper.

22

Transport roller 3 (Drive)

Transports paper transported from the paper teed tray 2 and the transport roller 2 to the transport roller 3.

23

Transport roller 3 (Idle)

Applies pressure to paper and the resist roller to transport the paper.

24

Transport roller 4 (Drive)

Transports paper transported from the transport roller 3 to the transport roller 15.

25

Transport roller 4 (Idle)

Applies pressure to paper and the resist roller to transport the paper.

26

Transport roller 5 (Drive)

Transports paper fed from the paper feed tray 4 to the transport rollers 6 and 7.

27

Transport roller 5 (Idle)

Applies pressure to paper and the resist roller to transport the paper.

28

Transport roller 6 (Idle)

Reduces friction between paper and the paper guide.

29

Transport roller 7 (Drive)

Transports paper transported from the transport roller 5 to the transport roller 10.

30

Transport roller 7 (Idle)

Applies a pressure to paper and the transport roller to provide a transport power of the transport roller to paper.

31

Transport roller 8 (Drive)

Transports paper transported from the paper feed tray 3 to the transport rollers 9 and 10.

32

Transport roller 8 (Idle)

Applies a pressure to paper and the transport roller to provide a transport power of the transport roller to paper.

33

Transport roller 9 (Idle)

Reduces friction between paper and the paper guide.

34

Transport roller 10 (Drive)

Transports paper transported from the transport rollers 7 and 8 to the transport roller 11.

35

Transport roller 10 (Idle)

Applies a pressure to paper and the transport roller to provide a transport power of the transport roller to paper.

36

Transport roller 11 (Drive)

Transports paper transported from the transport roller 10 to the transport roller 13.

37

Transport roller 11 (Idle)

Applies a pressure to paper and the transport roller to provide a transport power of the transport roller to paper.

38

Transport roller 12 (Idle)

Reduces friction between paper and the paper guide.

39

Transport roller 13 (Drive)

Transports paper fed from the paper feed trays 1, 3, and 4 to transport roller 15.

40

Transport roller 13 (Idle)

Applies a pressure to paper and the transport roller to provide a transport power of the transport roller to paper.

41

Transport roller 14 (Idle)

Reduces friction between paper and the paper guide.

42

Transport roller 15 (Drive)

Transports paper to the transport resist roller.

43

Transport roller 15 (Idle)

Applies a pressure to paper and the transport roller to provide a transport power of the transport roller to paper.

44

Transport roller 16 (Drive)

Transports paper from the fusing roller to the paper exit roller 1.

45

Transport roller 16 (Idle)

Applies a pressure to paper and the transport roller to provide a transport power of the transport roller to paper.

46

Transport roller 17 (Idle)

Reduces friction between paper and the paper guide.

47

Transport roller 18 (Idle)

Reduces friction between paper and the paper guide.

48

Transport roller 19 (Drive)

Transports paper from the transport from the paper exit roller 2 to the transport roller 20.

49

Transport roller 19 (Idle)

Applies a pressure to paper and the transport roller to provide a transport power of the transport roller to paper.

50

Transport roller 20 (Drive)

Transports paper transported from the transport roller 19 to the transport roller 21.

51

Transport roller 20 (Idle)

Applies a pressure to paper and the transport roller to provide a transport power of the transport roller to paper.

52

Transport roller 21 (Drive)

Transports paper transported from the transport roller 20 to the transport roller 15.

53

Transport roller 21 (Idle)

Applies a pressure to paper and the transport roller to provide a transport power of the transport roller to paper.

54

Transport roller 22 (Idle)

Reduces friction between paper and the paper guide.

55

Paper exit roller 1 (Drive)

Discharges paper to the paper exit tray. / Switches back paper.

56

Paper exit roller 1 (Idle)

Applies a pressure to paper and the paper exit roller to provide a transport power of the paper exit roller to paper.

57

Paper exit roller 2 (Drive)

Discharges paper. / Transports paper to the duplex (ADU) section.

58

Paper exit roller 2 (Idle)

Applies a pressure to paper and the transport roller to provide a transport power of the paper exit roller to paper.

59

Fusing roller (Pressing)

Applies a pressure to the fusing roller (heating).

60

Fusing roller (Heating)

Heat and press toner onto paper to fuse images.

61

Transfer roller 1A (Drive)

Transports paper (which is fed from the manual paper feed tray) to the transport roller.

62

Transfer roller 1A (Idle)

Applies a pressure to paper and the transport roller to provide a transport power of the transport roller to paper.

63

Paper exit roller 3 (Drive)

Discharges paper to the paper exit tray. /Switches back paper.

64

Paper exit roller 3 (Idle)

Applies a pressure to paper and the transport roller to provide a transport power of the transport roller to paper.

MX-M753N  ADJUSTMENTS AND SETTINGS  5 – 1

MX-M753N

Service Manual

 

Each adjustment item in the adjustment item list is associated with
a specific Job number. Perform the adjustment procedures in the
sequence of Job numbers from the smallest to the greatest.
However, there is no need to perform all the adjustment items. Per-
form only the necessary adjustments according to the need.

Unnecessary adjustments can be omitted. Even in this case, how-
ever, the sequence from the smallest to the greatest Job number
must be observed.
If the above precaution should be neglected, the adjustment would
not complete normally or trouble may occur.

ADJ 1

Adjusting the developing unit

1A

Adjust the developing doctor gap

1B

Adjust the developing roller main pole position

1C

Toner density control reference value setting

25-2

ADJ 2

Adjusting high voltage values

2A

Adjust the main charger grid voltage

8-2

2B

Adjust the developing bias voltage

8-1

2C

Transfer current adjustment

8-6

2D

Transfer belt cleaning voltage adjustment

8-17

2E

Transfer cleaning roller voltage adjustment

8-18

ADJ 3

Print engine image skew adjustment (LSU parallelism adjustment)

64-2

ADJ 4

Scan image distortion adjustment (OC 
mode)

4A

Scanner (reading) unit parallelism adjustment

4B

Scan image sub scanning direction distortion adjustment

4C

Scan image main scanning direction distortion adjustment

ADJ 5

Scanner image skew adjustment (DSPF 
mode)

5A

DSPF parallelism adjustment

5B

DSPF skew adjustment (Front surface mode)

64-2

5C

DSPF skew adjustment (Back surface mode)

64-2

ADJ 6

Scan image focus adjustment

6A

Image focus adjustment (Document table mode/DSPF front surface mode)

48-1

6B

Image focus adjustment (DSPF back surface mode)

ADJ 7

Image lead edge position, image loss, 
void area, image off-center, and image 
magnification ratio adjustment 
(automatic adjustment)

7A

Print image main scanning direction image magnification ratio automatic adjustment 
(Print engine)

50-28

7B

Print image off-center automatic adjustment (Print engine) (Each paper feed tray)

50-28

7C

Copy lead edge image reference position adjustment, image loss, void area, scanner 
image off-center, and scanner sub scanning direction image magnification ratio 
automatic adjustment (document table mode)

50-28

7D

Copy image off-center, image loss, void area, image lead edge position, and DSPF 
sub scanning direction image magnification ratio automatic adjustment 
(DSPF mode)

50-28

ADJ 8

Print lead edge image position, void area adjustment (Printer mode)

50-5

ADJ 9

CCD calibration

9A

CCD gamma adjustment (CCD calibration) (Document table mode)

63-3/63-5

9B

CCD gamma adjustment (CCD calibration) (DSPF mode)

63-3

9C

Shading adjustment (Calibration) (DSPF mode)

63-2

ADJ 10

Automatic adjustment of copy/printer density and gradation

46-74

ADJ 11

Copy density and gradation adjustment

11A

Automatic adjustment of copy density and gradation

46-24

11B

Manual copy density and gradation adjustment

46-16

11C

Copy density and gradation adjustment (Each copy mode) (Whole adjustment) 
(Normally unnecessary to adjust)

46-2

11D

Manual copy density and gradation adjustment for each copy mode 
(Normally unnecessary to adjust)

46-10

11E

Document background density reproducibility adjustment in the auto copy mode 
(Normally unnecessary to adjust)

46-32

11F

Color document reproducibility adjustment in the copy mode 
(Normally unnecessary to adjust)

46-37

11G

Manual copy density and gradation adjustment (DSPF mode) 
(Individual adjustment of the low density area and the high density area)

46-9

11H

Automatic copy density and gradation adjustment by the user 
(ENABLE/DISABLE setting and adjustment of the automatic copy density and 
gradation adjustment)

26-53

ADJ 12

Printer density and gradation adjustment

12A

Automatic adjustment of printer density and gradation

67-24

12B

Manual printer density and gradation adjustment

67-25

12C

Automatic printer density and gradation adjustment by the user 
(ENABLE/DISABLE setting and adjustment of the automatic printer density and 
gradation adjustment)

26-54

ADJ 13

Setting of the operating conditions for the automatic exposure mode in copy, scan, and FAX mode

46-19

ADJ 14

Paper size detection adjustment

14A

Manual paper feed tray paper width sensor adjustment

40-2

14B

DSPF tray paper size (width) sensor adjustment

53-6

14C

Adjust the paper width sensor for paper feed tray 3

40-12

ADJ 15

Adjusting the original size detection 
(in original table mode)

15A

Adjust the detection point of the original size sensor (in original table mode)

41-1

15B

Adjust the sensitivity of the original size sensor

41-2

ADJ 16

Touch panel coordinate setting

65-1

MX-M753N  ADJUSTMENTS AND SETTINGS  5 – 2

*1: ADJ7 is the automatic adjustment of ADJ18, 19, 20, and 21.
When ADJ7 is executed, there is no need to execute ADJ18, 19, 20, and 21.
ADJ18, 19, 20, and 21 are executed only when a manual adjustment is required.

 

NOTE: Be careful not to put a fingerprint or a foreign material on

the DV roller surface. If a fingerprints or a foreign material
is put on the surface, the picture quality may be degraded.

 

* The developing unit has been disassembled.
* The print density is low.
* The toner is excessively dispersed.

1)

Remove the developing unit of the machine.

2)

Remove the developing unit cover and doctor cover.

3)

Loosen the DV doctor fixing screws.

4)

Manually turn the DV roller to align the marking on the DV
roller surface with the DV doctor position.

ADJ 17

Fusing paper guide position adjustment

ADJ 18

Print engine image position, image 
magnification ratio, void area, off-center 
adjustment (manual adjustment)

18A

Print engine image magnification ratio adjustment (Main scanning direction)

50-10

18B

Print engine image position adjustment

50-10/50-1

18C

Print engine print area (void area) adjustment

50-10

ADJ 19

Scan image magnification ratio 
adjustment (Manual adjustment)

19A

Main scanning direction image magnification ratio adjustment 
(Document table mode)

48-1

19B

Sub scanning direction image magnification ratio adjustment (Document table mode)

48-1/48-5

19C

Main scanning direction image magnification ratio adjustment (DSPF mode)

48-1

19D

Sub scanning direction image magnification ratio adjustment (DSPF mode)

48-1

ADJ 20

Scan image off-center adjustment 
(Manual adjustment)

20A

Scan image off-center adjustment (Document table mode)

50-12

20B

Scan image off-center adjustment (DSPF mode)

50-12/50-6

ADJ 21

Copy image position, image loss, and 
void area adjustment 
(Manual adjustment)

21A

Copy image position, image loss, void area adjustment (Document table mode)

50-1

21B

Document scan position adjustment (DSPF mode scanner scan position adjustment)

53-8

21C

Copy mode image loss adjustment (DSPF mode)

50-6

ADJ 22

Finisher and punch unit adjustments 
(alignment, punch hole position, staple 
position, folding position)

22A

MX-FN15/MX-PN4

3-10

22B

MX-FN16/MX-PN4

22C

MX-FN14/MX-PN10

MX-M753N  ADJUSTMENTS AND SETTINGS  5 – 3

5)

Insert a 0.43mm clearance gauge in between the DV roller and
DV doctor so that the gauge is positioned at a distance of 40
mm to 70 mm from the DV doctor end face.

6)

Tighten the DV doctor fixing screws while pressing the DV doc-
tor in the arrow direction.
(This should be done for both front and rear frames.)

7)

On both sides of the DV doctor and at its center, make sure
that the DV doctor gap is 0.43

0.03mm.

* When inserting a clearance gauge, take care not to damage the

DV doctor or MG roller.

Repeat steps 2 to 6 until the DV doctor gap meets the requirement.

 

* The developing unit has been disassembled.
* The print density is low.
* The toner is excessively dispersed.

1)

Remove the developing unit.

2)

Remove the developing unit cover and blade cover, and then
place the developing unit on a level surface.

3)

Attach a piece of string to a sewing needle or pin.

4)

With the string in hand, bring the needle closer to the DV roller
while keeping the needle parallel with the roller. (Do not use a
clip, which does not accurately indicate the position.)

5)

Keeping the needle 2 to 3 mm off the DV roller surface, mark
the DV roller surface at an extension of the needle tip. (Do not
let the needle tip contact the DV roller.)

6)

Measure the distance between the marking on the DV roller
and leading edge of the DV doctor, and make sure that it is
19

0.5mm.

If this requirement is not met, do the following steps.

7)

Remove the front cover.

20mm

50mm

20mm

50mm

19 0.5mm