DOWNLOAD Sharp AR-C150 (serv.man5) Service Manual ↓ Size: 4.23 MB | Pages: 62 in PDF or view online for FREE

Item

NO.

Correction items

Factors

Purpose and effect

Change item

NOTE

6

Toner
concentration
control correction

Toner
concentration
sensor
correction 

Developing capability
change and toner
concentration sensor
detection error due to
developer/toner
characteristics
(chargeability) change
(temperature/humidity
change, developer
aging change)

For change  in developing
capability and the toner
concentration sensor error  due
to change in developer and
toner  characteristics
(chargeability)(temperature/
humidity change, developer
aging), the toner concentration
is maintained in the proper
level, the proper density print is
maintained, background copy is
prevented, and toner dispersion
is prevented.

Toner
concentration
control data

Reset by SIM 25-2.

7

Image reading
correction 

Dark component
correction 

The CCD output
components include
non-image components.

Non-image component is
subtracted from the CCD output
to provide the effective image
component  only. 

Only effective
image
component is
taken out from
the CCD output. 

White balance
correction 

CCD sensitivity
fluctuation/Optical
system light quantity
fluctuation

CCD output fluctuation due to
CCD sensitivity fluctuation and
optical system light quantity
fluctuation is corrected.

The gain of the
amp for CCD
(image signals)
is adjusted. 

Shading
correction 

CCD pixel
fluctuations/Optical
system light quantity
unevenness

"Uneven density in reading
images due to CCD pixel
fluctuation, optical system light
quantity unevenness is
corrected. "

The output gain
of each pixel of
CCD is adjusted.

8

CCD gamma
correction 

"Gamma fluctuation in
R, G, B"

Gamma fluctuation of R/G/B is
corrected to make proper
balance of gray (color) when
reading images.  

Gamma of each
of R/G/B.

9

Half tone image
correction 

Laser beam duty
correction 1

OPC drum/developing
section
(developer/toner)
characteristics change
(Temperature/humidity
change,
developer/toner
deterioration)

"For the image forming section
characteristics change, the
color balance (gamma) set with
SIM 46-24(21) is maintained.
(The half tone density is
maintained.)"

Laser beam
power (Laser
beam ON duty)

10

Color balance
adjustment

Laser beam duty
correction 2

Color balance
fluctuations between
machines

Set the color balance fluctuation
between the machines to the
standard color balance
(gamma). 

Laser beam
power (Laser
beam ON duty)

11

Link between
color balance
adjustment data
and half tone
image correction
data

Link between color balance
adjustment data and half tone
image correction data

12

User auto color
balance
adjustment (Auto
gamma setup)

Color balance adjustment is
performed by the user. 

Laser beam
power (Laser
beam ON duty)

13

Resist roller
RPM correction 

Paper conditions
change (Transport
capability change)

When the paper transport
capability is changed due to
humidity, the relative transport
speed of the transfer belt and
the resist roller is changed to
assure proper paper transport
capability in the transfer section.

Resist roller RPM

AR-C150

3 – 2

Conditions for correction and execution timing are shown below.
List of correction operations (process correction operations) in the AR-C150 image forming section.

Item

No

Correction items

Execution conditions/Operation timing

1

Image density sensor sensitivity
correction (Calibration) (Gain
adjustment)

Before correction of the image forming section (process correction)

2

OPC drum marking sensor sensitivity
adjustment (Calibration) (Gain
adjustment)

1. Before correction of the image forming section (process correction)
2. When warming up after turning on the power and canceling the simulation

3

OPC drum deterioration correction 

Laser beam power
correction

The specified OPC drum rotating time (every specified haurs)

4

High density (saturation density) image
correction 

Developing bias
voltage correction 

SIM44-6 (Forcible execution)
1. During warming immediately after turning on the power and canceling the

sleep mode and when the fusing temperature is the specified
temperature or below. 

2. After completion of printing after the specified time of the Magenta OPC

drum total rotating time after high density (saturation density) image
correction by condition 1. If, however, high density (saturation density)
image correction was performed in advance under the other condition
than this condition, the correction under this condition is not performed.

3. When the temperature in the previous correction is the specified

temperature or below, and the temperature difference from the previous
correction is the spcified temperature or more after the specified time of
the previous correction.

4. When correction is not made for the specified time or more after

correction of the previous high density (saturation density) image forming
correction, and after completion of copying.

5. When the toner concentration control correction for humidity change is

made and the toner concentration control level is reset to the original
level and the specified time passes. When, however, high density
(saturation density) image forming correction is made under the other
condition than this condition in advance to it, correction under this
condition is not performed.

6. During warming up after replacement of the OPC drum. (Replacement of

the OPC drum is judged by execution of SIM 24-7.)

7. During warming up after replacement of developer (Replacement of

developer is judged by execution of SIM 25-2.)

Main charger grid
voltage correction 

After correction of the developing bias voltage

5

Transfer capability correction

Transfer voltage
correction 

When temperature/humidity is changed.
When switching the paper kind. 
When printing the back surface of paper in the duplex print mode. 

6

Toner concentration control correction 

Toner concentration
sensor correction 

When the developing voltage is corrected more than the specified voltage
and temperature and humidity are changed immediately after correction of
the developing bias voltage. 
When the developer counter (timer) reaches the specified values.  

7

Image reading correction 

Dark component
correction 

1. During warming up after turning on the power and canceling the
simulation or the sleep mode. 

White balance
correction 
Shading correction 

8

CCD gamma correction

Execute with SIM 63-3.

9

Half tone density image correction 

Laser beam duty
correction 1

SIM44-26 (Forcible execution)
1) After the high density (saturation density) image correction (when the

developing bias voltage is changed by more than 45V in correction) 

2) During warming up after replacement of OPC drum (Replacement of the

OPC drum is judged by execution of SIM 24-7.)

3) During warming up after replacement of developer (Replacement of

developer is judged by execution of SIM 25-2.)

10

Color balance adjustment

Laser beam duty
correction 2

SIM46-24(21)

11

Half tone image correction initial setup

SIM44-21

12

User auto color balance adjustment
(Auto gamma setting)

Performed by the user program.

13

Resist roller RPM correction 

When temperature/humidity is changed.

AR-C150

3 – 3

The toner image patch density on the transfer belt is precisely de-
tected by correcting changes in sensitivity due to dirt on the image
density sensor and a change in the temperature during the high den-
sity (saturation) image correction and the half tone image correction.
Thus the above correction is made correctly.
There are two sensor; one for color and the other for monochrome. 
The correction is made for each of them. 

(Calibration operation 1 of the image density sensor for color) 
1) Perform calibration of the image density sensor by attaching the

adjustment sheet to the transfer belt with SIM 44-4. 
Read the reflection lights from the adjustment sheet to obtain the
LED drive voltage (Vref) which provides the specified output. 
Specified output (PSS C TARGET ID): Vmin + 2.0v

Vmin: Sensor output level (dark voltage) when the sensor output
is zero.

2) The calibration plate in the sensor section is shifted to the sensor

position (driven by the solenoid), and the reflection ratio of the cali-
bration plate is read by the sensor at the LED drive voltage (Vref)
obtained in the above procedure.
The sensor output level at that time is stored as Vssc.

(Calibration 2 of the image density sensor for color) 
This operation is automatically performed before the harf tone image
density correction and the high density (saturation density) image cor-
rection. 
The calibration plate in the sensor section is shifted to the sensor po-
sition (driven by the solenoid) to obtain the LED drive voltage (Vrefc)
so that the sensor output level is Vssc. 
The obtained LED drive voltage (Vrefc) is used for detection of the im-
age density.

(Calibration of image density sensor for monochrome)
The sensor LED drive voltage is changed and the reflection lights
from the transfer belt surface are read by the sensor. Obtain the sen-
sor LED drive voltage (Vrefk) when the sensor output voltage is at the
specified level (Reference Level (PSS B TARGET ID)(Vmin + 2.6v).

Vmin: Sensor output level (dark voltage) when the sensor output is
zero. 

The obtained LED drive voltage (Vrefb) is used for detection of the
image density. 

A change in the sensitivity due to dirt on the OPC drum marking sen-
sor and a change in the temperature is corrected to make precise de-
tection of the number and the position of the OPC drum marking. 

By detecting the OPC drum marking position, the following operations
are performed. 

1) Control of the toner image patch formation position in the high

density (saturation density) image correction and the half tone im-
age correction.

2) Control of each OPC drum phase in printing

3) By detecting the number of the OPC drum marking, the type of the

OPC drum is identified and the laser beam power and the main
charger grid voltage are switched depending on the OPC drum
type.

(Calibration)
The sensor LED drive voltage is changed and the reflection lights
from the OPC drum surface are read by the sensor. Obtain the sen-
sor LED drive voltage (Vrefd) when the sensor output voltage is at the
specified level (3.6V). 

Vmin: Sensor output level (dark voltage) with the sensor input is zero.

LSU

LSU

LSU

LSU

Y

C

M

BK

Drum mark
sensor

Drum mark
sensor

Drum mark
sensor

Drum mark
sensor

Humidity sensor

Calibration plate

Image density sensor

Sensor drive (LED) voltage

IMAGE DENSITY SENSOR CALIBRATION 1 (for Color sensor)

Sensor output
level (voltage)

V min (LED off)

Reference Level
(PSS C TARGET ID)
(Vmin + 2.0v)
(Set by SIM44-4)

Reference sensor drive (LED) voltage (Vref)

Used by sensor adjusting
sheet and SIM44-4

Reference Level
(Vssc)

Step 2

Used by sensor reference
plate and SIM44-4

Step 3

Step 1

Sensor drive (LED) voltage

IMAGE DENSITY SENSOR CALIBRATION 2 (for Color sensor)

Sensor output
level (voltage)

V min (LED off)

Reference sensor drive (LED) voltage (Vrefc)
(Actual sensor drive (LED) voltage

Reference
Level (Vssc)

Used by sensor calibration
plate and SIM44-4

Step 1

Step 2

Sensor drive(LED) voltage

IMAGE DENSITY SENSOR CALIBRATION 1 (for Monochrome sensor)

Sensor output
level (voltage)

V min (LED off)

Reference Level
(PSS B TARGET ID)
(Vmin + 2.6v)

Set by SIM44-4
(Transfer belt serface level)

Step 1

Step 2

Reference sensor drive (LED) voltage (Vrefk)
(Actual sensor drive (LED) voltage

AR-C150

3 – 4

The obtained LED drive voltage (Vrefd) is used for detection of the
OPC drum marking. 

A decline in the photo sensitivity due to deterioration of the OPC drum
is corrected by increasing the laser beam power according to the
OPC drum rotating time (the degree of use) to maintain the proper
print density (prevention against a decline in the print density). 

Deterioration of the OPC drum advances in proportion to the print
quantity. 

There are following causes of deterioration of the OPC drum (decline
in sensitivity).

1) OPC drum membrane decrease (due to mechanical stress by the

cleaning blade and developer (mainly by the cleaning blade)
(partly by friction heat))

2) Photo stress due to laser beams and external lights

3) Electrical stress (high voltage) due to chargers

The laser beam power is increased according to the count value of
the OPC drum counter (time) as shown below:

The OPC drum counter is reset by executing TC 24-7.

a. Outline and purpose
The development conditions are varied by changes in the charac-
teristics of toner and developer and deterioration of developer caused
by changes in temperature and humidity. 
To solve the above problem, the developing bias voltage is varied ac-
cording to the conditions, maintaining the proper print density and
preventing against background copying.
There are following factors for changes in the development condi-
tions. 

1) Developer deterioration (Change in the developer shape caused

by friction heat and mechanical stress in the developing unit and
abrasion of the coating layer)

2) Changes in the developer characteristics caused by changes in

temperature and humidity (Changes in electrical characteristics
depending on temperature and humidity)

Deterioration of developer advances in proportion to the print
quantity.

 
b. Details of operation 

<1> In the case of color mode
(Case 1) When the OPC drum correction counter is reset with SIM 24-7, the correction conditions are initialized and correction is performed from the

developing bias voltage set with SIM 44-5. 

Sensor drive(LED) voltage

PHOTOCONDUCTOR SENSOR CALIBRATION

Sensor output

level(voltage)

V min(LED off)

5.0v

Reference

Level(3.6v)

Reference sensor drive(LED) voltage(Vrefd)

Photo conductor surface
reflection level

Step 1

Step 2

LASER BEAM POWER CORRECTION (for Photoconductor waredown correction)

[uW]

Laser beam
power

Start point(Reset by T.C24-7)

Photoconductor drum rotation time(h)

Higher

Image patch density

100

90

83

Lower

0

100

200

300

400

500

600

Develping bias voltage

Limit(-600v)

CASE 2

Y/M/C PAT TARGET
ID(Set by SIM44-4)

Limit(-125v)

Correction voltage 1(PADV1)

Correction voltage 2(PADV2)

1st stage

PTK1/BS1(ID1)

PTK2/BS2(ID2)

PTK3/BS3(ID3)

PTK1/BS1(ID1)

PTK2/BS2(ID2)

PT3/BS3(ID3)

PTK4/BS4(ID4)2

PTK5/BS5(ID5)

PTK6/BS6(ID6)

CASE 1

AR-C150

3 – 5