Sharp AR-C172M (serv.man4) Service Manual ▷ View online
AR-C172M DESCRIPTIONS OF EACH SECTION 7 - 16
(3) Major parts/signals functions and operations
RW: Abbreviation of Related Wiring, which means the said load is specified in the related figure of the mechanical and the electrical sec-
tions.
(4) Operational descriptions
a. Drum cartridge and toner cartridge drive
The drive power for the drum cartridges are transmitted from the
drive motor (DM) to the drum gears.
drive motor (DM) to the drum gears.
The toner cartridge is driven through the drum gear and the con-
nection gear.
nection gear.
The motor (stepping motor) for black is driven by the drive signal
sent directly from the PCU, and the motors color are driven by the
drive signals sent from the PCU through the driver PWB.
sent directly from the PCU, and the motors color are driven by the
drive signals sent from the PCU through the driver PWB.
b. LED (writing) unit
Four LED (writing) units are provided for each of Yellow, Magenta,
Cyan, and Black.
Cyan, and Black.
Each LED (writing) unit converts YMCK dot image data outputted
from the ICU PWB into LED light, and radiate the light onto the
OPC drum, forming electrostatic latent images on the OPC drum.
from the ICU PWB into LED light, and radiate the light onto the
OPC drum, forming electrostatic latent images on the OPC drum.
Since the position of each LED unit of CMYK is shifted in the
paper transport direction, the above operation depends on the rel-
ative position and differs in the operating timing.
paper transport direction, the above operation depends on the rel-
ative position and differs in the operating timing.
2
5
4
4
7
1
8
9
3
6
5
11
10
No.
Name
Code, Signal name
Function
1
OPC drum (YMCK)
—
Forms electrostatic latent images.
2
Main charger (YMCK)
MC
Charges the OPC drum surface negatively.
3
Discharge lens
—
Discharges the OPC drum surface.
4
Cleaning blade
—
Cleans the OPC drum surface to remove residual toner.
5
Toner reception seal
—
Seals to prevent against toner leakage.
6
Waste toner transport screw
—
Transports toner scraped by the cleaning blade to the waste toner box of the
toner cartridge.
toner cartridge.
7
MC cleaner
—
Cleans the MC (charging plate).
8
LED unit
—
Converts image signals into LED light and radiates it onto the OPC drum.
9
Developing roller
—
Attaches toner to the OPC drum. (Do not touch the developing roller.)
10
DV CRUM (Y, M, C, K)
—
Memory for toner cartridge data (counter, etc.)
11
Waste toner box
—
Collects waste toner transported from the drum cartridge.
RW
Grid biks
GB
Controls the drum surface potential.
RW
Discharge lamp
DL
Radiates lights onto the discharge lens.
RW
Drum motor A, A’, B, B’
DM A, A’, B, B’
Drives the OPC drum.
RW
Toner empty sensor
TES
Detects the toner quantity in the toner cartridge.
AR-C172M DESCRIPTIONS OF EACH SECTION 7 - 17
• LED unit composition
c. OPC drum section operations
The OPC drum surface is charged negatively by the main charger,
and LED light of images are radiated onto the OPC drum surface
by the LED (writing) unit to form electrostatic latent images.
and LED light of images are radiated onto the OPC drum surface
by the LED (writing) unit to form electrostatic latent images.
1) The OPC drum surface is negatively charged by the main
charger.
The screen grid is attached to the main charger unit. The OPC
drum is charged at a voltage nearly same as the voltage
applied to the screen grid.
drum is charged at a voltage nearly same as the voltage
applied to the screen grid.
2) LED light is radiated onto the OPC drum surface by the LED
(writing) unit to form electrostatic latent images.
When LED light is radiated onto the OPC drum CGL, positive
and negative charges are generated. Positive charges gener-
ated in the CGL are attracted and moved by negative charges
of the OPC drum, and negative charges by positive charges of
the aluminum layer of the OPC drum. Therefore, on the OPC
drum surface and in the aluminum layer, positive and negative
charges are neutralized, reducing the OPC drum surface
potential.
and negative charges are generated. Positive charges gener-
ated in the CGL are attracted and moved by negative charges
of the OPC drum, and negative charges by positive charges of
the aluminum layer of the OPC drum. Therefore, on the OPC
drum surface and in the aluminum layer, positive and negative
charges are neutralized, reducing the OPC drum surface
potential.
Electric charges remain in the areas where LED light is not
radiated onto the OPC drum.
radiated onto the OPC drum.
As a result, electrostatic latent images are formed on the OPC
drum surface.
drum surface.
Charges are disposed in direct proportion to the amount of
light received.
light received.
3) Clean and remove residual toner from the OPC drum with the
cleaning blade after transfer operations.
Removed residual toner is transported to the waste toner sec-
tion of the toner cartridge by the waste toner transport screw.
tion of the toner cartridge by the waste toner transport screw.
4) The whole surface of the OPC drum is discharged.
By radiating discharge lamp light onto the discharge lens, light
is radiated through the discharge lens to the OPC drum sur-
face.
is radiated through the discharge lens to the OPC drum sur-
face.
When discharge lamp light is radiated onto the OPC drum
CGL, positive and negative charges are generated.
CGL, positive and negative charges are generated.
Positive charges generated in the CGL are attracted and
moved by negative charges of the OPC drum, and negative
charges by positive charges of the aluminum layer of the OPC
drum. Therefore, on the OPC drum surface and in the alumi-
num layer, positive and negative charges are neutralized,
reducing the OPC drum surface potential, preparing the drum
surface for the new copy cycle.
moved by negative charges of the OPC drum, and negative
charges by positive charges of the aluminum layer of the OPC
drum. Therefore, on the OPC drum surface and in the alumi-
num layer, positive and negative charges are neutralized,
reducing the OPC drum surface potential, preparing the drum
surface for the new copy cycle.
Item
Content
Print width
314mm
Total number of dots
7424 dot
Resolution
600dpi
LED
composition
composition
Number of LED chips
58 chip
Number of dots
128 dot
Lens
Selfoc lens
Aluminum
layer
OPC drum
CTL
CGL
High voltage unit
Main corona unit
Screen grid
OPC drum
LED light
Aluminum
layer
layer
OPC drum
CGL
CTL
OPC drum
Lens
CTL
CGL
Aluminum
layer
layer
Aluminum
layer
layer
CTL
CGL
AR-C172M DESCRIPTIONS OF EACH SECTION 7 - 18
d. Developing section (composed of four units of YMCK)
operations
Electrostatic latent images generated on the OPC drum by the
LED (writing) units are converted into visible images by toner.
LED (writing) units are converted into visible images by toner.
Toner in the developing unit is agitated by the mixing roller.
By mixing operation, toner is negatively charged due to mechani-
cal friction.
cal friction.
The developing bias voltage (negative) is applied to the develop-
ing roller.
ing roller.
The diflerence for the voltage potential between the toner and DV
roller surface attracts the toner to the DV roller.
roller surface attracts the toner to the DV roller.
In the areas of the OPC drum, when the charge was detected, the
voltage potential difference is greater than the DV roller. Therefore
the toner is attracted from the DV roller to the drum.
voltage potential difference is greater than the DV roller. Therefore
the toner is attracted from the DV roller to the drum.
In the unexposed areas of the drum, the potential on the DV roller
created by the bias voltage and therefore the toner to not attracted
to those areas of the drum.
created by the bias voltage and therefore the toner to not attracted
to those areas of the drum.
Negatively charged toner is attracted and attached to the exposed
area on the OPC drum surface where the negative potential was
reduced by LED exposure.
area on the OPC drum surface where the negative potential was
reduced by LED exposure.
On the other hand, in the areas on the OPC drum where exposure
was not made, the positive potential is higher than the developing
bias voltage, repelling toner.
was not made, the positive potential is higher than the developing
bias voltage, repelling toner.
<1> Remaining toner quantity detection
Rotation of the detection lever connected to the mixing roller is
sensed by the sensor (TES) to detect the remaining toner
quantity.
sensed by the sensor (TES) to detect the remaining toner
quantity.
<2> Waste toner collection
Waste toner collected by the drum cleaning blade is trans-
ported to the waste toner box of the toner cartridge by the
toner transport spring in the drum unit.
ported to the waste toner box of the toner cartridge by the
toner transport spring in the drum unit.
Aluminum
layer
layer
CGL
CTL
OPC drum
Drive
Drive
Own weight
Own weight
OPC drum
AR-C172M DESCRIPTIONS OF EACH SECTION 7 - 19
B. Disassembly/assembly/maintenance
(1) Process section maintenance target parts
✕
: Check (Clean, replace, or adjust as necessary.)
❍
: Clean
▲
: Replace
∆
: Adjust
✩
: Lubricate
❏
: Shift position
Note: When replacing the OPC drum, execute SIM 25-1 for 2 minutes. (This simulation is executed in order to avoid generation of stripes on
a half-tone print image.)
Unit name
No.
Part name
When
calling
50K
100K 150K 200K 250K 300K 350K 400K
Remark
Drum peripheral
section
section
1
Drum (B/W, Color)
▲
▲
▲
▲
▲
▲
▲
▲
2
Charging unit
▲
▲
▲
▲
▲
▲
▲
▲
3
Cleaner blade
▲
▲
▲
▲
▲
▲
▲
▲
4
Toner reception seal
▲
▲
▲
▲
▲
▲
▲
▲
5
Drum cartridge
▲
▲
▲
▲
▲
▲
▲
▲
When replacing the unit
Developing section
(integrated with
toner cartridge)
(integrated with
toner cartridge)
6
Toner cartridge
Replaced by user when toner empty
(or at the specified distance covered)
LED
7
LED lens
❍
❍
❍
❍
❍
❍
❍
❍
❍
2
2
4
4
3
3
1
1
7
6
5
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