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MX-M1204  ADJUSTMENTS  5 – 5

2) Attach the digital multi-meter between the connector CN3 pin

(11) on the high voltage pwb and GND.

3)

Enter the adjustment value with 10-key, and press [EXECUTE]
key.
The DV BIAS voltage is outputted for 30sec.

4)

Check the output voltage with the digital multi-meter.
If the output voltage is outside the specified range described in
the above table, perform procedures 2 thru 4 until the specified
value is reached. 

NOTE:
If the specified voltage is not obtained by changing the adjust-
ment value, one of the following parts may be defective. 
-  High voltage PWB
-  PCU PWB
-  Development unit
-  High voltage circuit electrode

 

This adjustment is needed in the following situations:
* The high voltage PWB has been replaced. 
* U2 trouble has occurred.
* The PCU PWB has been replaced.
* The EEPROM of the PCU PWB has been replaced.
1) Enter the Sim. 8-6 mode. 
2) Select the output mode to be adjusted with the scroll button.

3) Enter the adjustment value with 10-key, and press [OK] button.

The adjustment value is set.
Normally when the default value is set, the specified voltage is
outputted.
When [EXECUTE] button is pressed, the adjustment value is
saved and the transfer voltage is outputted simultaneously.
Since the actual output cannot be checked, if it is presumed to
be abnormal even though the adjustment value is set to the
default value, replace the high voltage pwb. 

 

This adjustment is needed in the following situations:
* When the photoconductor drum is replaced.
* When the front surface potential sensor is replaced.
* When the main charger unit is replaced.
* When the main high voltage PWB is replaced.
* When the photoconductor unit (process unit) is disassembled.

* The PCU PWB has been replaced.
* The EEPROM of the PCU PWB has been replaced.
* Before executing the image adjustment
1)

Enter the Sim.44-3 mode. 

2)

Select the adjustment mode.
-  INI DARK VO:

When the OPC drum is replaced, select this mode.

-  DARK VO: 

In the other cases, select this mode.

3)

Press [EXECUTE] key.
[EXECUTE] button is highlighted, and the OPC drum is rotated
to start the OPC drum dark potential adjustment operation.
After completion of the adjustment, [EXECUTE] button returns
to the normal display.
The main charger grid voltage is automatically corrected until
the OPC drum dark potential becomes the specified value.

&1

A

TC PLAIN SPX

Transfer current (THV+): Standard paper front surface

0 - 255

142

174

45μA

55μA

B

TC PLAIN DPX

Transfer current (THV+): Standard paper back surface

0 - 255

112

147

35μA

45μA

C

TC HEAVY SPX

Transfer current (THV+): Heavy paper front surface

0 - 255

142

174

45μA

55μA

D

TC HEAVY DPX

Transfer current (THV+): Heavy paper back surface

0 - 255

128

142

40μA

45μA

E

TC OHP

Transfer current (THV+): OHP

0 - 255

96

127

30μA

40μA

F

TC FRONT EDGE BIAS

Transfer current (THV+): Paper lead edge

0 - 255

32

32

10μA

10μA

G

TC ADSORPTION BIAS

Transfer current (THV+): Absorption process

0 - 255

96

127

30μA

40μA

H

TC INTERVAL BIAS

Transfer current (THV+): Between paper

0 - 255

48

48

15μA

15μA

I

TC CLEANING AC SPX

Transfer cleaning AC (THVAC)

0 - 255

191

191

4500V

4500V

J

TC CLEANING DC -

Transfer cleaning DC bias - (THV–)

0 - 255

135

201

-400V

-600V

K

TC CLEANING BRUSH +

Transfer CL brush print + (THVCL (+))

0 - 128

109

109

200V

200V

L

TC CLEANING BRUSH -

Transfer CL brush cleaning - (THVCL (–))

128 - 255

169

169

-500V

-500V

M

PTDL SPX

PTDL front surface

0 - 255

15

20

1.2mA

1.6mA

N

PTDL DPX

PTDL back surface

0 - 255

15

20

1.2mA

1.6mA

TopPage

: ‘14/Feb

: ‘16/Aug.

MX-M1204  ADJUSTMENTS  5 – 6

 

 

The check and the adjustment are required in the following cases:
* When the developing unit is disassembled.
* When the print image density is too low.
* When there is a thin spot on a print image.
* When the print image density is uneven.
* When there is abnormally much toner dispersion.
1) Remove the developing unit from the machine, and remove

the cover and the guide as shown in the figure below.

2)

Loosen the developing doctor blade fixing screw.

3)

Insert a thickness gauge of 0.42mm into the gap of 40mm -
70mm from the edge of the developing doctor blade.

4)

Push the developing doctor blade in the direction of the devel-
oping roller (arrow direction), and tighten the fixing screw of
the developing doctor blade. (Perform the similar procedure for
the front frame and the rear frame.)

5)

Check to confirm that the doctor gap is in the range of 0.42 



0.025mm at two positions in 40mm - 70mm from the both 

sides of the developing doctor blade. When inserting the thick-
ness gauge, be sure not to scratch the developing doctor
blade and the developing roller.

 

The check and the adjustment are required in the following cases:
* When the developing unit is disassembled.
* When the print image density is too low.
* When there is a thin spot on a print image.
* When the print image density is uneven.
* When there is abnormally much toner dispersion.
1)

Place the developing unit on a flat surface.

2)

Remove developer from the developing roller.

3)

Put a string on a needle or a pin. (Do not use a paper clip,
which cannot provide an accurate position.)

70mm

40mm

70mm

40mm

0.42   0.025mm

+

-

0.42   0.025mm

+

-

MX-M1204  ADJUSTMENTS  5 – 7

4) Hold the string, and put the needle closer to the developing

roller.

5) With the needle 2 - 3mm apart from the developing roller, mark

the intersect of the extended line and the developing roller sur-
face. (Do not bring the needle into contact with the developing
roller.)

6) Measure the height of the marking position, and check to con-

firm that it is 60.5

 0.5mm.

If the height is not in the above range, adjust the developing
roller main pole position by the following procedure. 
Loosen the fixing screw of the developing roller main pole
adjustment plate, and move the adjustment plate in the arrow
direction to make an adjustment.

Repeat the procedures 4 thru 6 until the developing roller main
pole position is within the specified range.
After completion of the adjustment of the developing roller
main pole position, tighten the fixing screw of the developing
roller main pole adjustment plate.

 

This adjustment is required in the following case:
* When developer is replaced.

Note:
Never execute this adjustment unless developer is replaced. 
Select the most suitable simulation mode according to the mainte-
nance case. 

[Setting with the Sim. 25-2 mode]
1)

Enter an input of Sim. 25-2 with the front cover open.

2)

After entering the input, close the front cover.

3)

Open the toner cartridge tray.

4)

Press [EXECUTE] key.
[EXECUTE] key is highlighted, and the developing roller
rotates. The toner density is detected by the toner density sen-
sor, and the output value is displayed. 
After execution of the above operation for about 3min, the
average value of the toner density sensor detection levels is
set (saved) as the reference toner density control value. 
After completion of the reference toner density control value
setting, [EXECUTE] key returns to the normal display. This
indicates completion of the setting. 

When setting of the reference toner density control value has
failed, [EE-EU], [EE-EL] or [EE-EC] is displayed.

<<Error display list (AUTO DEVE ADJUSTMENT)>>

2   3mm

60.5   0.5mm

+

-

60.5   0.5mm

+

-

EE-EL

EL abnormality

The sensor output 
level is less than 
26, or the control 
voltage level 
exceeds 197.

In case of an 
error, the humidity 
area, the 
execution 
transition target, 
and the execution 
control voltage are 
not registered.

EE-EU

EU abnormality

The sensor output 
level exceeds 
200, or the control 
voltage level is 
less than 49.

EE-EC

EC abnormality

The sample level 
is not 120 

 5 

when the 
automatic density 
adjustment is 
being performed.

MX-M1204  ADJUSTMENTS  5 – 8

 

 

This adjustment is needed in the following situations:
* The LSU has been replaced or removed.
* Print images are distorted.
This adjustment should be followed by:
* ADJ3C Adjust the print image off-center (print engine section)
1) Enter the Sim.64-2 mode. 
2) Set the conditions as shown below.

The paper feed tray with A3 (11 X 17) paper in it is selected.

3) Press [EXECUTE] button.

The grid pattern image is outputted.

4) Check the printed grid pattern for distortions.

[Check Method 1]
Compare the front frame side and rear frame side of the
printed paper in terms of the distance between the outer end of
the grid pattern image and the edge of the paper.
No adjustment is needed if the difference between these
dimensions is within 0.5 mm.

[Check Method 2]
If the right-angle level of the traverse print line is 0.5mm or less
with respect to the longitudinal print line of paper, no adjust-
ment is needed.

Carry out the following work if the situation is unsatisfactory.

5)

Open the front cabinet. Remove the toner cartridge unit.

6)

Remove the the process cover.

7)

Loosen the fixing screw of the print image distortion adjust-
ment cam. Adjust the angle of the print image distortion adjust-
ment cam to set the print image distortion to the minimum.

When the vertical line image is tilted to the left with the front
frame side as the reference, turn the print image distortion
adjustment cam clockwise to change the angle. 
When the vertical line image is tilted to the right with the front
frame side as the reference, turn the print image distortion
adjustment cam counterclockwise to change the angle. 
Repeat steps 3 to 7 until an acceptable result is obtained.

A

PRINT PATTERN 
(1 - 22, 53 - 58, 71 - 78 ) 

Used to specify the print 
pattern.
(* For details, refer to the 
following descriptions.)

5

B

DOT1 
(DOT1>=2 IF A : 2, 11) 

Used to set the print dot 
number. (Self print pattern: 
for m by n)

1

C

DOT2 
(DOT2 <= 100 IF A : 59) 

Used to set the empty dot 
number. (Self print pattern: 
for m by n)

254

D

DENSITY 
(FIXED ”255” IF A : 9) 

Used to specify the print 
gradation.

255

E

RESOLUTION (DPI) 

Used to select the 
resolution. (600DPI, 
1200DPI)

1

F

MULTI COUNT

Number of print

1

G

EXPO
SURE 
(2 to 8 
IF  A  :   
14  to  19) 

THROUGH

Used to 
specify 
the 
exposure 
mode

No process 
(Through)

8 

(STAN

DARD

DITHER) 

CHAR/PIC

Text/Printed 
Photo

CHAR/
PRPIC

Text/ 
Photograph

CHAR

Text

PRINT PIC

Printed Photo

PRINT 
PAPER

Photograph

MAP

Map

STANDARD
DITHER

Dither without 
correction

R

F

b

a