Sharp AR-C150 (serv.man5) Service Manual ▷ View online
1) Three toner patched of different densities are made on the OPC
drum by the three different bias voltages, and are transferred on
the transfer belt. The developing bias voltage (Dvpx) at that time is
as follows:
the transfer belt. The developing bias voltage (Dvpx) at that time is
as follows:
2) Three toner patch densities (reflection lights) are read by the im-
age density sensor to check that the intersection of lines connect-
ing three toner patch density points reaches the reference density
level.
(The reference density level is set with SIM 44-4. It differs depend-
ing on the color.)
ing three toner patch density points reaches the reference density
level.
(The reference density level is set with SIM 44-4. It differs depend-
ing on the color.)
If the above condition is satisfied, the correction developing bais
voltage (PADVx) and the developing bias voltage (DVx) are calcu-
lated for the reference density level by the linear approximation
method.
voltage (PADVx) and the developing bias voltage (DVx) are calcu-
lated for the reference density level by the linear approximation
method.
If the condition of (2) is not satisfied, perform the following procedure.
3) The toner patch making conditions are changed as shown below
to make three toner patches of different densities on the OCP
drum and transfer them on the transfer belt.
drum and transfer them on the transfer belt.
4) Three toner patch densities (reflection lights) are read by the im-
age density sensor to check that the intersection of lines connect-
ing three toner patch density points reaches the reference density
level.
(The reference density level is set with SIM 44-4. It differs depend-
ing on the color.)
If the above condition is satisfied, the correction developing bias
voltage (PADVx) and the actual developing bias voltage (DVx) are
calculated for the reference density level by the linear approxima-
tion method.
Procedures 3) and 4) are repeated until the above condition is sat-
isfied. (However, the multiplier "n" increases.)
ing three toner patch density points reaches the reference density
level.
(The reference density level is set with SIM 44-4. It differs depend-
ing on the color.)
If the above condition is satisfied, the correction developing bias
voltage (PADVx) and the actual developing bias voltage (DVx) are
calculated for the reference density level by the linear approxima-
tion method.
Procedures 3) and 4) are repeated until the above condition is sat-
isfied. (However, the multiplier "n" increases.)
(Case 2) When the developing bias voltage correction is performed for the second time after performing once, the developing bias voltage set in the
previous correction is used as the start point.
The basic operations are the same as (Case 1).
DEVELOPING BIAS VOLTAGE CORRECTION(Color)
DEVELOPING BIAS VOLTAGE CORRECTION(Color)
Higher
Image patch density
100
90
83
Lower
100
200
300
400
500
600
Develping bias voltage
Limit(-600v)
PTK1/BS1(ID1)
PTK2/BS2(ID2)
PTK3/BS3(ID3)
PTK2/BS2(ID2)
PTK5/BS5(ID5)
PTK1/BS1(ID1)
PTK6/BS6(ID6)
Y/M/C PAT TARGET ID(Set by
SIM44-4)
SIM44-4)
Limit(-125v)
Correction voltage 1(PADVx1)
Correction voltage 2(PADVx2)
2nd stage
1st stage
1st stage
PT3/BS3(ID3)
PTK4/BS4(ID4)2
AR-C150
3 – 6
<2> In the case of the monochrome mode
The basic operations are the same as the color mode3. The following items differ in the color mode and in the monochrome mode.
The basic operations are the same as the color mode3. The following items differ in the color mode and in the monochrome mode.
(Color mode)
In the case of the color mode, when the toner patch density is read by the image density sensor, the higher the developing bias is, the more the
toner quantity is, increasing reflection lights, resulting in an increased sensor output.
toner quantity is, increasing reflection lights, resulting in an increased sensor output.
(Monochrome mode)
In the case of the monochrome mode, on the contrary to the color mode, the higher the developing bias is, the more the toner quantity is and the
more the lights are absorbed, decreasing the reflection lights, resulting in a decreased sensor output.
more the lights are absorbed, decreasing the reflection lights, resulting in a decreased sensor output.
The above operation is performed for each color.
DEVELOPING BIAS VOLTAGE CORRECTION(Black)
DEVELOPING BIAS VOLTAGE CORRECTION(Black)
Lower
Image patch density
15
Higher
0
100
200
300
400
500
600
Develping bias voltage
Limit(-600v)
PTK2/BS2(ID2)
PTK3/BS3(ID3)
PTK4/BS4(ID4)2
PTK2/BS2(ID2)
PTK5/BS5(ID5)
PTK6/BS6(ID6)
PT3/BS3(ID3)
CASE 2
K PAT TARGET
ID(Set by SIM44-4)
ID(Set by SIM44-4)
1st stage
Limit(-150v)
Correction voltage 1(PADVK1)
Correction voltage 2(PADVK2)
PTK1/BS1(ID1)
PTK1/BS1(ID1)
CASE 1
DEVELOPING BIAS VOLTAGE CORRECTION(Black)
DEVELOPING BIAS VOLTAGE CORRECTION(Black)
Lower
Image patch density
15
Higher
0
100
200
300
400
500
600
Develping bias voltage
Limit(-600v)
PTK2/BS2(ID2)1
PTK4/BS4(ID4)2
PTK2/BS2(ID2)2
PTK1/BS1I1D1)2
PTK6/BS6(ID6)2
PT3/BS3(I31)2
K PAT TARGET
ID(Set by SIM44-4)
ID(Set by SIM44-4)
Correction voltage 2(PADVK2)
Limit(-150v)
PTK3/BS3(I31)1
Correction voltage 1(PADVK1)
PTK5/BS5(ID5)2
PTK1/BS1(ID1)1
1st stage
2nd stage
AR-C150
3 – 7
(2) Main charger grid voltage correction
a. Outline and purpose
When the developing bias voltage is changed, the main charger grid voltage is corrected in order to maintain the constant difference (voltage differ-
ence of 200V) between the bias voltage and the main charger grid voltage to prevent against background copy.
When the developing bias voltage is changed, this correction is performed automatically.
When the developing bias voltage is changed, the main charger grid voltage is corrected in order to maintain the constant difference (voltage differ-
ence of 200V) between the bias voltage and the main charger grid voltage to prevent against background copy.
When the developing bias voltage is changed, this correction is performed automatically.
b. Details of operation
If the main charger grid voltage is not –200V higher than the developing bias voltage, background copy is made.
If the main charger grid voltage is not –200V higher than the developing bias voltage, background copy is made.
After correction of the developing bias voltage, the main charger grid voltage is automatically added with the correction quantity of the developing bias
voltage.
Therefore, the actual main charger grid voltage becomes as follows:
voltage.
Therefore, the actual main charger grid voltage becomes as follows:
E. Transfer correction
(1) Outline and purpose
Correction is performed for the following three ffactors by changing the transfer voltage.
1) Correction for changes in the transfer capability due to changes in temperature and humidity.
2) Correction for changes in the transfer efficiency due to the paper kind.
3) Correction for changes in the transfer efficiency due to changes in the paper surface conditions.
(2) Details of operation
The transfer voltage is changed according to the above conditions.
TRANSFER VOLTAGE CORRECTION TABLE
(PRINT MODE)
Condition
level
Humidity
sensor
count value
Normal paper(Simplex)
Cardbord
Transparency sheet
Normal paper(Duplex)
K
C
M
Y
K
C
M
Y
K
C
M
Y
K
C
M
Y
1
1 – 10
3KV
3KV
3KV
3KV
3KV
3KV
3KV
3KV
3KV
3.5KV
4KV 4.5KV 3KV
3KV
3KV
3KV
2
11 – 18
2.75KV 2.75KV 2.75KV 2.75KV 3KV
3KV
3KV
3KV
3KV
3.5KV
4KV 4.5KV 2.75KV 2.75KV 2.75KV 2.75KV
3
(Standard)
19 – 30
2.5KV
2.5KV
2.5KV
2.5KV
3KV
3KV
3KV
3KV
3KV
3.5KV
4KV 4.5KV 2.5KV 2.5KV
2.5KV
2.5KV
4
31 – 40
2.25KV 2.25KV 2.25KV 2.25KV 3KV
3KV
3KV
3KV
3KV
3.5KV
4KV 4.5KV 2.25KV 2.25KV 2.25KV 2.25KV
5
41 – 50
2KV
2KV
2KV
2.25KV 2.5KV 2.5KV 2.5KV 2.5KV 2.75KV 3.25KV 3.75KV 4.5KV 2KV
2KV
2KV
2.25KV
6
51 – 60
1.75
1.75
1.75
2.25KV 2KV
2KV
2KV
2KV 2.5KV
3KV
3.5KV 5KV 1.75KV 1.75KV 1.75KV 2.25KV
7
61 –
1.75
1.75
1.75
2.25KV 2KV
2KV
2KV
2KV 2.5KV
3KV
3.5KV 5KV 1.75KV 1.75KV 1.75KV 2.25KV
IMAGE DENSITY CORRECTION(PROCESS ORRECTION) MODE
Humidity
condition
level
Humidity
sensor count
value
Image density correction(Process
correction)
K
C
M
Y
1
1 – 10
3KV
3KV
3KV
3KV
2
11 – 18
2.75KV 2.75KV 2.75KV 2.75KV
3 (Standard)
19 – 30
2.5KV
2.5KV
2.5KV
2.5KV
4
31 – 40
2.5KV
2.5KV
2.5KV
2.5KV
5
41 – 50
2.5KV
2.5KV
2.5KV
2.5KV
6
51 – 60
2.25KV 2.25KV 2.25KV 2.25KV
7
61 –
2KV
2KV
2KV
2KV
CONDITION LEVEL TABLE
Condition level
Humidity sensor count value
1
1 – 10
2
11 – 18
3 (Standard)
19 – 30
4
31 – 40
5
41 – 50
6
51 – 60
7
61 –
F. Toner concentration control correction
(1) Outline and purpose
This operation is to correct changes in the developer characteristics
due to aging and changes in the environment (temperature and hu-
midity).
The developer characteristic (chargeability) fluctuates greatly in the
early stage, and fluctuates by changes in temperature and humidity
and by aging.
The change in the developer chargeability may lead to an error in the
toner concentration sensor operation.
If there occurs an error in the toner concentration sensor operation,
the toner concentration cannot be controlled properly.
due to aging and changes in the environment (temperature and hu-
midity).
The developer characteristic (chargeability) fluctuates greatly in the
early stage, and fluctuates by changes in temperature and humidity
and by aging.
The change in the developer chargeability may lead to an error in the
toner concentration sensor operation.
If there occurs an error in the toner concentration sensor operation,
the toner concentration cannot be controlled properly.
The developing density is also changed by the change in the devel-
oper chargeability.
oper chargeability.
These factors may cause undertoner, overtoner, or insufficient charg-
ing, resulting in an abnormal print density.
ing, resulting in an abnormal print density.
To prevent against the above, the reference toner concentration con-
trol level is changed according to the situations to keep the constant
toner concentration.
This correction keeps the constant toner concentration, prevents
against toner dispersion, and stabilizes the print density.
trol level is changed according to the situations to keep the constant
toner concentration.
This correction keeps the constant toner concentration, prevents
against toner dispersion, and stabilizes the print density.
(2) Details of operation
(Correction for aging)
Correction is performed by changing the reference toner concentra-
tion control level according to the developer correction counter (devel-
oper unit operation time).
The developer correction counter is reset by execution of SIM 25-2.
Correction is performed by changing the reference toner concentra-
tion control level according to the developer correction counter (devel-
oper unit operation time).
The developer correction counter is reset by execution of SIM 25-2.
(Correction for changes in humidity)
When the developing bias voltage is changed and the humidity rank
level s changed in the high density (saturation density) image correc-
tion, the correction is performed by changing the reference toner con-
centration control level.
When the developing bias voltage is changed and the humidity rank
level s changed in the high density (saturation density) image correc-
tion, the correction is performed by changing the reference toner con-
centration control level.
AR-C150
3 – 8
G. Image reading correction
(1) Dark component correction
a. Outline and purpose
The CCD by its nature outputs a certain level of voltage component even though there is no reception of lights. This voltage component is called the
dark component. Since the dark component must not be included in the image signal, it is stored in advance and must be subtracted from the image
component when images are actually read. .
The CCD by its nature outputs a certain level of voltage component even though there is no reception of lights. This voltage component is called the
dark component. Since the dark component must not be included in the image signal, it is stored in advance and must be subtracted from the image
component when images are actually read. .
This operation is called the dark component correction.
b. Details of operation
1) With the scanner lamp OFF, the CCD output is read and stored as the dark component. (This operation is performed for every warm-up.)
1) With the scanner lamp OFF, the CCD output is read and stored as the dark component. (This operation is performed for every warm-up.)
In an actual image scanning, the dark component is subtracted from the CCD output component, and the remainder is used as the actual image com-
ponent.
ponent.
The above operation is performed for the CCD of each color (R, G, B).
(2) White balance correction
a. Outline and purpose
The CCD output gain is adjusted to the proper level so as to read im-
ages in the wide range of densities correctly.
The CCD output gain is adjusted to the proper level so as to read im-
ages in the wide range of densities correctly.
b. Details of operation
1) The scanner lamp is lighted and the shading sheet (white) is read
1) The scanner lamp is lighted and the shading sheet (white) is read
by the CCD. Adjust the amp gain in the CCD PWB so that the
max. CCD output level is 240, and store the gain.
The above operation is performed for the CCD element of each
color (R, G, B).
max. CCD output level is 240, and store the gain.
The above operation is performed for the CCD element of each
color (R, G, B).
3) In an actual image scanning, the image signals are amplified with
the gain adjusted in the above procedure and are outputted to the
ICU PWB.
ICU PWB.
(3) Shading correction
a. Outline and purpose
This correction is performed to correct unevenness of the image den-
sity due to the following factors.
This correction is performed to correct unevenness of the image den-
sity due to the following factors.
1) Light quantity is decreased as apart from the optical center be-
cause of the optical structure.
2) Unevenness of brightness of the scanner lamp
3) Sensitivity variation in the CCD pixels
b. Details of operation
1) The scanner lamp is lighted and the shading sheet (white) is read
1) The scanner lamp is lighted and the shading sheet (white) is read
by the CCD. The max. output level of the CCD at that time is 255.
2) Calculate the correction coefficient from the ratio of the max. out-
put level (Wmax) and each CCD element output level (Wt(n)) and
store it.
store it.
Correction coefficient Wtc(n) = Wmax / Wt(n)
3) Obtain the actual image scanning level (Ioutc(n)) from the CCD
detection level and the correction coefficient in an actual image
scanning.
scanning.
Ioutc(n) = Wtc(n) x Iout(n)
Perform the above operation for the CCD element of each color
(R, G, B).
(R, G, B).
–
=
Original image data
signal(Including dark component)
Dark component(Deduct)
True image data
signal
signal
CCD output level (Dark component)
in the no image condition(Black)
Scanner lamp off
DOCUMENT
CCD
WHITE SHEET
LAMP ON
LAMP OFF
CCD
0
Dark component level (Pdcl)
255
240 (max.) Adjust the gain
so that the max. level is 240.
(Pmax)
so that the max. level is 240.
(Pmax)
Ptl' = (Ptl - Pdcl) / (Pmax - Pdcl)
×
255
Shading correction is performed for each target
pixel according to the result of the above calculation.
pixel according to the result of the above calculation.
SHARDING CORRECTION (DARK COMPONENT CORRECTION,WHITE LEVEL CORRECTION)
CCD output level
AR-C150
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