Sharp AR-M550 (serv.man12) Service Manual ▷ View online
AR-M550/M620 DETAILS OF EACH SECTION 6 - 70
C. Operational descriptions
Electrostatic latent images formed on the OPC drum by the LED (writ-
ing) unit (LED image light) are converted into visible images by toner.
ing) unit (LED image light) are converted into visible images by toner.
Toner in the developing unit is stirred by the mixing roller.
When toner is stirred, it is negatively charged by mechanical friction.
The developing bias voltage (negative) is applied to the developing
roller.
roller.
Negatively charged toner is attracted and attached to the area on the
OPC drum where negative voltage is reduced by exposure.
OPC drum where negative voltage is reduced by exposure.
On the other hand, the negative voltage at an area where exposure is
not made is higher than the developing bias voltage, and toner is not
attached.
not made is higher than the developing bias voltage, and toner is not
attached.
Aluminum
layer
CGL
CTL
-500v
+150v
Cleaning
mode
mode
Developing
mode
mode
Drum
AR-M550/M620 DETAILS OF EACH SECTION 6 - 71
D. Maintenance and parts replacement
(1) Maintenance list
✕
: Check (Clean, replace, or adjust as necessary.)
❍
: Clean
▲
: Replace
∆
: Adjust
✩
: Lubricate
❏
: Shift position
(2) Maintenance and parts replacement
(List of Replacement Parts)
a. Developing unit
1) Take out the developing tank.
a-1. Developer
1) Take out the developing tank. (See “a. Developing unit” in this sec-
tion)
2) Remove the DV cover.
AR-M550U/M550N (PM: 250K)
When
calling
250K 500K 750K 1000K 1250K 1500K 1750K 2000K
Remark
AR-620U/M620N (PM: 300k)
300K 600K 900K 1200K 1500K 1800K 2100K 2400K
Unit name
No.
Part name
Developing
section
section
1
Developer
▲
▲
▲
▲
▲
▲
▲
▲
Supply when
installing
installing
2
DV seal
▲
▲
▲
▲
▲
▲
▲
▲
3
MG holder F/R
❍
❍
❍
❍
❍
❍
❍
❍
❍
4
Side seal F/R
▲
▲
▲
▲
▲
▲
▲
▲
4
4
3
1
2
3
No.
Unit
Parts
a
Developing unit
1
Developer
▲
2
DV seal
▲
3
MG holders F and R
❍
4
Side seals F and R
▲
5
Toner concentration sensor
a-3
a-3
a-5
a-4
a-4
a-1
a
a-2
2
1
AR-M550/M620 DETAILS OF EACH SECTION 6 - 72
3) Turning the MG roller, take out the old developer.
4) Insert the new developer.
a-2. DV seal
1) Take out the developing tank. (See “a. Developing unit” in this sec-
tion)
2) Take out the old DV seal.
3) Wipe the sealing face with alcohol.
4) Affix the new DV seal at the reference position.
a-3. MG holders F and R
1) Take out the developing tank. (See “a. Developing unit” in this sec-
tion)
2) Remove the DV cover. (See “a-1. Developer” in this section)
3) Remove the doctor cover.
4) Remove the DV cover front.
5) Remove the bias line and main pole position adjusting plate and
screws.
6) Remove the MG gear and screws.
7) Remove the side seals F and R.
AR-M550/M620 DETAILS OF EACH SECTION 6 - 73
8) Remove the MG roller unit.
9) Remove the doctor attaching plate.
10) Remove the MG holders F and R.
a-4. Side Seals F and R
1) Take out the developing tank.
2) Remove the doctor cover.
3) Peel off the right and left side seals.
4) Clean the peeled area.
5) Peel off the new right and left seals from the mounting paper and
affix in the designated positions.
a-5. Toner concentration sensor
1) Remove the developing tank. (See “a. Developing unit” in this sec-
tion)
2) Remove the DV cover. (See “a-1. Developer” in this section)
3) Remove the toner concentration sensor.
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