JP2003057891A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of realizing density adjustment in a short time by shortening a density target value setting time performed by changing toner concentration by the consumption of toner and replenishment with toner. SOLUTION: This image forming device is equipped with a patch forming means for forming a plurality of toner patches having different density and forming a plurality of density patches on a recording medium, a density sensor for obtaining 1st density data shoeing the density of a plurality of toner patches, a density data acquiring part for acquiring 2nd density data showing the density of a plurality of density patches, and a density control means for adjusting an image forming parameter based on relation between the 1st density data and the 2nd density data. Then, the patch forming means forms the toner patch and the density patch again by adjusting exposing light quantity when all of the 2nd density data is larger or smaller than specified target density.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention
Image forming devices used in copying machines, printers, etc.
You. 2. Description of the Related Art Conventionally used in copiers and printers, etc.
An electrophotographic image forming apparatus emits light along a document surface.
Image signal obtained by scanning or external input
Exposure light modulated based on image signal is uniformly charged
The latent image is formed by irradiating the photosensitive drum and the latent image is formed.
Developed with toner by image device
Forms an image, and transfers and fixes the toner image on paper.
The method of forming an image is used,
To ensure that the density of the image is
It is formed in a non-image area, its density is measured, and the measured
By comparing the density of the toner patch with the target value,
-Image forming parameters that affect image density such as replenishment
ADC (Auto density co.)
Control method is generally used. However, the state of the transfer unit and the fixing unit is
It differs from image forming apparatus to
Fluctuates due to environmental changes.
Even if the density of the formed toner patch is the same,
The density of the formed image may not be the same. So
Here, the toner patch is printed on paper and the density patch
And select the desired density gradation from the density patches
To obtain a density patch having the desired density gradation.
-Set the patch density as the target value, or
Measures the density of the density patch and
By determining whether the switch concentration is within an acceptable range.
It is necessary to reset the target density. JP-A-11-
No. 174748 discloses that a toner image on a photosensitive drum before transfer is transferred.
Toner patch and density patch after fixing on paper.
And adjust the density gradation to form a toner patch.
Density of the toner patch on the photoconductor drum before transfer
Is measured using a density sensor and set on paper.
The applied density patch is transferred to the image reading section of the image forming apparatus.
And the relationship between the density data
A toner patch to obtain a density patch of a desired density.
The density of the image is calculated, and the calculated density is used in the image forming process.
There is disclosed a technology for setting a concentration target value in a semiconductor device. According to this technique, the density formed on the paper
Read patches using the image reading unit of the image forming device
Target density is within the range of
Calculate the density of the toner patch using the correlation.
If the density target value is automatically set,
There is an advantage that the time for resetting is short. SUMMARY OF THE INVENTION [0005]
According to the technology disclosed in JP-A-11-174748,
The target density of the image was read using an image reading unit, etc.
Out of the density range of the density patch fixed on the paper
In this case, toner supply or toner consumption
After changing the mixing ratio of the toner, the toner patch is
Formed on the body or fixed on paper to measure the density of each
If it takes time to set the target concentration
There is a drawback. FIG. 1 is a schematic diagram of Japanese Patent Application Laid-Open No. H11-174748.
In the technology disclosed in
FIG. 2 is a flowchart, and FIG.
It is an explanatory view of a setting method. Note that the vertical axis in FIG.
The density data of the toner patch measured by the
Patches on paper after fixing read using a reading unit
The density data of the image is shown.
Toner patches formed by changing the floor and on paper
Plotted the measured density of the density patch fixed on the
Things. [0007] In FIG. 1, the operator has three levels.
Place the paper on which the density patch changed on the floor is printed
"Copy" on the platen of the image reading unit
(S-100). Then, the light is
Is the image data corresponding to the density patch obtained by
From the first to the third level, for example, in the direction of increasing darkness
The density (IIT1,
IIT2, IIT3. However, IIT3 is better than IIT2
Larger, IIT2 is greater than IIT1)
(S-101). Next, the density I of the second level density patch
Compare IT2 with target density of image (IIT target value)
(S102). Then, as shown in FIG.
If IT2 is greater than the IIT target value, the first level
Density IIT1 of the degree patch and the target density of the image (IIT target
(S103). And IIT1 is I
If it is smaller than the IT target value, the second level density patch
The density of the second level toner patch corresponding to the density IIT2
Data Radc2 and the density data of the first level patch image
1st level toner patch density data corresponding to IIT1
Using the data Radc1 to determine the toner patch density target value
Target ΔRadc target value = (Radc1-Radc)
2) × (IIT target value−IIT2) / (IIT1-II)
T2) is obtained (S104). By the way, ADC sensor
Output increases as the density decreases. On the other hand, when IIT1 is larger than the IIT target value,
If the target density of the image is
Out of the density range of the density patch
Consuming toner because it is judged to be too dark
(S105). Then, toner is consumed, and
At the stage when the degree has become thin, re-use the toner patch and density patch
Is formed, and the steps from the “copy” scan (S-100) are performed.
Need to be repeated. The density IIT of the second-level density patch
2 and a target density of the image (IIT target value) (S1).
02), and as shown in FIG.
If smaller than the target value, the density of the third level density patch
Compare IIT3 with target density of image (IIT target value)
(S106). Then, IIT3 is greater than the IIT target value.
If it is larger, the density of the third level density patch IIT3
Corresponding third-level toner patch density data Radc
3 and the second level corresponding to the density IIT2 of the density patch.
Using the density data Radc2 of the two-level toner patch
ΔRadc from the target density value of the reference toner image
Standard value = (Radc3-Radc2) × (IIT target value−
IIT2) / (IIT3-IIT2) is obtained (S10
7). Then, the deviation from the density target value of the reference toner image
When the ΔRadc target value is calculated (S104, S10
7), the calculated displacement ΔRadc target value and the second water
The second-level tone corresponding to the density IIT2 of the standard density patch
Sum Radc density with density data Radc2 of nap patch
The target value is set as the density target value (S108), and the Radc density is set.
The degree target value is stored (S109). On the other hand, when IIT3 is smaller than the IIT target value,
If the target density of the image is
Out of the density range of the density patch on the
Toner concentration is too low.
Perform (S110). Then, the toner density becomes
At the stage when it becomes exhausted, toner patches and density patches are formed again
Steps from "copy" scan (S-100)
Need to be repeated. The present invention has been made in consideration of the above circumstances, and has been made in consideration of the above circumstances.
Scan using an image reading unit, etc.
Target density of the image from the density range of the density patch on
If the toner is removed, replenish the toner and replenish the toner.
Concentration target value by adjusting the concentration of
The required image density in a short time.
It is an object of the present invention to provide an image forming apparatus. [0012] According to the present invention, there is provided the present invention for achieving the above object.
A bright image forming apparatus irradiates exposure light onto an image carrier and
Forming an electrostatic latent image and applying toner to the electrostatic latent image to form a toner image
And finally transfer and transfer the toner image onto a recording medium.
And fix the image comprising the fixed toner image on the recording medium.
In the image forming apparatus to be formed, a plurality of tones having different densities are used.
To form a toner patch.
Transfer and fixation on the recording medium
Multiple density patches consisting of toner patches fixed on the body
Patch forming means for forming a
Multiple toners before being transferred to the recording medium
-By measuring the patch density,
-A density sensor for obtaining the first density data representing the density of the patch.
Formed on a recording medium by the patch forming means.
These are obtained from the density measurement of multiple density patches
The second density data representing the densities of the plurality of density patches is acquired.
The density data acquisition unit to be obtained and measurement by the density sensor
Density data obtained by the above and the above density data acquisition
Based on the relationship with the second concentration data acquired by the
Image type that affects the density of the image formed on the recording medium
Density control means for adjusting the composition parameters.
Switch forming means, wherein the density data acquisition unit acquires
Any of the second density data is larger than a predetermined target density.
Or any of the second density data is the target density.
If the exposure light is smaller than
Adjust the amount of light for multiple toner patches and multiple
Is formed to form a density patch. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described.
explain. FIG. 3 is an image forming apparatus according to an embodiment of the present invention.
FIG. The image forming apparatus shown in FIG.
There is a platen 2 where 1 is set, and below the platen 2
Denotes an exposure lamp 3, a scanning optical system 4, a CCD sensor 5,
The image sensor 35 includes a CCD sensor 5
Represents the reflected light of the light emitted from the exposure lamp 3 onto the document,
Light is received via the scanning optical system 4 and photoelectrically converted into 256 gradations.
Image data represented by the density of This image
The data is temporarily stored in the image memory 6 of the image reading unit 35.
You. The image data temporarily stored in the image memory 6 is subjected to image processing.
The image processing unit (IPS) 7 performs predetermined image processing and performs image processing.
Is sent to the laser exposure device 8. Leh
The exposure device 8 includes a light emitting driver 8a and a semiconductor laser 8b.
The light emission driver 8a is controlled by the light intensity determination unit 28.
Generates an image signal obtained by modulating the signal of the set level.
To drive the semiconductor laser 8b.
A laser beam is emitted based on the image signal. Semiconductor laser
The laser light emitted from the laser 8 b
By the rotation, the photosensitive drum 10 is scanned in the axial direction. The photosensitive drum 10 rotates in the direction of arrow A.
Along the circumference of the photosensitive drum 10 in the rotation direction A.
Charging device 11, developing device 12, transfer device 13, density sensor 1
4, a cleaner 15, and a static eliminator 16 are arranged. The charger 11 uniformly covers the surface of the photosensitive drum.
And the charged photosensitive drum 10 is irradiated with laser light.
When projected, an electrostatic latent image is formed. The developing device 12 is filled in a developer stirring chamber.
An auger 12a for mixing and charging the two-component developer,
It is rotatably arranged at a position close to the photosensitive drum 10.
Developing roller 12b, and a bias voltage applying unit 17
When a developing bias is applied to the developing roll from
The developer on the developing roll 12b is applied to the electrostatic latent image on the drum 10.
As a result, a toner image is formed on the photosensitive drum 10.
On the other hand, the toner box 18 connected to the developing device 12
Stores toner for developer. In developing unit 12
Is controlled by the motor driver 19.
Spence motor 20 drives toner box 18
The toner mixture ratio in the developer (TC%)
Is kept at a predetermined level. The transfer unit 13 faces the photosensitive drum 10.
The photosensitive drum 1 is disposed at the transfer position 29 of the toner image
0 and the toner on the photosensitive drum 10
An electric field for attracting an image to the paper P is applied to the photosensitive drum 1
The toner image on 0 is transferred to the paper P. The paper P is
The photoconductor drum and the transfer device 13 are paired by the paper feed roll 21.
It is sent to the opposite transfer position 29. The toner image transferred onto the paper P is
Is transported to the fixing device 23 while being guided by the
Is heated and pressurized to fix the paper, and the discharge roll 2
4 to the tray 25, and a series of image forming operations
finish. In addition to the above, the image forming apparatus includes a toner cartridge.
Switch, density patch, toner patch density
There is an image control unit 26 for calculating a standard value and the like. Image control
The unit 26 forms toner patches at predetermined intervals.
And the density of the toner patch is measured by the density sensor 14.
The measured value is compared with the target concentration value, and
An image that affects density, such as toner replenishment, if it comes off
Density to maintain proper image density by adjusting formation parameters
Controlling. However, the transfer device 13 and the fixing device 23
Is not constant and the toner particles measured by the density sensor
After fixing, the density of the switch is within the allowable range.
The density of the image may be incorrect, in which case
It is necessary to reset the concentration target value. So, for example,
When the target density setting mode is selected from the
The unit 26 forms a toner patch on the photosensitive drum 10
After the density is measured by the density sensor 14, the toner
The patches are transferred and fixed to form density patches. Soshi
And place the density patch on the platen 2 of the image forming apparatus.
Read by CCD sensor 5, density data of 256 gradations
To obtain the image data. Then, measurement is performed by the density sensor 14.
Measured data and density data read by CCD sensor 5
Get a density patch of desired density based on the correlation with
And calculate the density of the toner patch to obtain the target density value.
Normally, this target density value and the measured value of the density of the toner patch are
To adjust image forming parameters by comparing
U. However, the density data read by the CCD sensor 5 is
As a result of comparison by the comparison unit 34 provided in the control unit 26, the density
Data is greater than the target image density,
Or, if both are smaller than the target image density,
In this case, it is set by the control unit 26 and the light intensity determination unit 28.
Light intensity to a predetermined intensity, and the changed light intensity
Forming a toner patch based on the temperature on the photosensitive drum again,
A patch image having a shifted image density is formed on a sheet.
At this time, the density sensor 14 detects the toner whose density has shifted.
The density of the patch is measured, and a CCD sensor 5 such as an image reading unit is used.
Reads the density of the density patch whose density has shifted. As described above, the density obtained by reading the density patch
If all data is greater than or
If all the degree data are small, the toner mixture ratio (TC
%) Does not have to wait for the laser exposure unit 8 to change.
Can be changed by temporarily changing the exposure intensity
You can change the density of the
The target density value can be set in a short time using the changed density.
Can be reset. In addition, reset the target density value.
The flow will be described later. Here, the density sensor 14 detects the transfer position 29
Than the photosensitive drum 10 in the rotation direction A.
However, it can also be located downstream. In that case,
The measurement of the density of the toner patch by the
In the case of No. 9, it is necessary to perform the transfer without transferring the image onto the paper. There
To form the same toner patch twice, one of which is the density
Used to measure density with sensor 14, the other on paper
Used to transfer and fix to form density patches
You. The density sensor 14 is arranged upstream of the transfer position 29.
Measurement takes longer than in the case where
Is separated from the developing device 12 and may be contaminated by toner.
Decrease. FIG. 4 shows the density target value in this embodiment.
It is a figure showing an operator operation procedure at the time of determination. Referring to FIG. 4, the operator first selects "PG
(Pattern Generator) Copy "Pro
The program is executed (S10). This "PG Copy" pro
Gram forms a toner patch on the photoreceptor drum and
The density sensor 14 measures the density and obtains density data.
Transfer the toner patch whose measurement has been completed
Control program to print out density patches by wearing
It is. The details of the "PG copy" program will be described later.
I do. Next, the operator prints out
"PG copy" is set on the platen (S20),
"IIT (Image Input Termina)
1) Execute the "measurement" program (S30). This "I
The "IT measurement" program was set on the platen
Read the image density of "PG copy" with CCD sensor
Obtain density data, read it with this CCD sensor,
Data and density data measured with the PG Copy program
Is used to calculate the toner patch density target value (Radc target value).
Value). Note that "IIT
Details of the "measurement" program will be described later. FIG. 5 is a diagram showing “PG copy” in this embodiment.
-Is a flowchart showing the processing procedure of the program.
You. First, as shown in FIG.
Measure the density of the light drum background and obtain VCLEAN
(S200). Next, the photosensitive material is formed to form a toner patch.
The light intensity of the laser
Level (for example, 150 μW) (S2
01). The light intensity level is set by the control unit from the light intensity determination.
This is done by giving a command to the fixed part. And
Read the toner patch data from the
Driving the light emitting driver based on the data, the first level
Exposure light with a light intensity of from a semiconductor laser irradiates electrostatic latent image
Is formed, and a first-level toner patch is formed on the photosensitive drum.
At the same time as resetting the timer for controlling the patch formation position.
(S202). Then, adjust the light intensity to an intermediate level.
(For example, 220 μW) (S20)
3) When the timer reaches a predetermined value (Tmsec)
Forming a second-level toner patch on the photosensitive drum
(S204). Continue to increase the light intensity to a higher level (e.g.,
For example, 290 μW) (S205).
Timing when the time reaches a predetermined value (2 × Tmsec)
To form a third level toner patch on the photosensitive drum.
(S206). From the first formed on the photosensitive drum
The density of the third level toner patch is determined by the
The third level is the strongest corresponding to the intensity of
The standard is the thinnest. The toner packages of the first to third levels are
Switches at the timing when they pass the measurement point of the density sensor.
Is measured, and the density value of the first-level toner patch (VPA
TCH1), the second-level toner patch density value (VPA
TCH2), the density value of the third level toner patch (VPA
TCH3) (S207 to S20)
9). Whether the first concentration measurement was performed at the measurement point of the concentration sensor
The toner patches up to the third level are the same at the transfer position.
(S210), and is transferred onto the paper by the fixing device.
To form a density patch 30 (S211).
As shown in FIG. 6, the density patch 30 on the paper is
Density corresponding to the first level in the direction of arrow C where the paper is transported
Patch 30a, patch 30b corresponding to the second level, third
Patches 30c corresponding to the levels are arranged at equal intervals, and thereafter,
"PG copy" in the "IT measurement" program
Treated. On the other hand, the density sensor detects the density of the toner patch.
Degree value, VPATCH1, VPATCH2, VPATCH
3 and the density value VCLEAN of the background of the photosensitive drum
Is multiplied by a coefficient (here, 200) to obtain a relative density value Rad.
Calculate c1, Radc2, Radc3 and calculate the result
Is R as a measurement value of each toner patch by the density sensor.
It is stored in an AM or the like (S212). Note that the concentration sensor
Light emitting diode (LED) and photodiode (PD)
, The density is determined by the amount of reflected light.
Since the measurement is performed, the measurement value of the density sensor
The lower the value, the higher the value.
You. Therefore, Radc1 is the largest and Radc3
Is the smallest. FIG. 7 shows the "ITT measurement" in this embodiment.
Is a flowchart showing the processing procedure of the "set" program.
You. In FIG. 7, the printed
The operator changes the density patch with three levels to the image.
“Copy” scanning on the platen of the reading unit (S-
300). And it is obtained by photoelectric conversion by CCD sensor.
Also, from the image data corresponding to the density patch,
Density patches that have shifted from the first to the third level in
Each concentration (IIT1, IIT2, IIT3.
IIT3 is greater than IIT2, and IIT2 is
3 is obtained (S-301). Next, the second
The density IIT2 of the level density patch and the target density (I
(IT target value) by the comparing unit (S302). Soshi
If IIT2 is greater than the IIT target value, the first water
The density IIT1 of the quasi-density patch and the target density (II
T (target value) is compared by the comparing unit (S303). Soshi
If IIT1 is smaller than the IIT target value, the second water
The second-level tone corresponding to the density IIT2 of the standard density patch
And the first-level density data Radc2.
Level toner patch corresponding to the switch density IIT1
From the density target value using the density data Radc1 of
Transfer ΔRadc target value = (Radc1-Radc2) ×
(IIT target value-IIT2) / (IIT1-IIT2)
Is obtained (S304). On the other hand, when IIT1 is larger than the IIT target value,
The density pattern on the paper read using the image reading unit.
The density of each of the switches is out of the target density,
The toner patch is determined to be too dark.
DOWN processing is performed to lower the density of light (S30).
5). The density IIT of the second level density patch
2 and the target density of the image (IIT target value)
(S302), when IIT2 is smaller than the IIT target value.
The density IIT3 of the third level density patch and the image density
The comparison unit compares the target density (IIT target value) with the reference density (S30).
6). And when IIT3 is larger than the IIT target value
Is the third level corresponding to the density IIT3 of the third level density patch.
The density data Radc3 of the three-level toner patch and the second water
The second-level tone corresponding to the density IIT2 of the standard density patch
Density target using the density data Radc2
Deviation from the value ΔRadc target value = (Radc3-Ra
dc2) × (IIT target value−IIT2) / (IIT3-
IIT2) is obtained (S307). And the concentration target value
When the deviation ΔRadc target value is calculated from (S3
04, S307), and the calculated displacement ΔRadc target
Value and the density IIT2 of the second level density patch
With the density data Radc2 of the second level toner patch
The sum and the Radc density target value are set to the density target value (S30).
8) The Radc concentration target value is stored (S309). one
If the direction IIT3 is smaller than the IIT target value, the image reading
The density of the density patch read using the
It is judged that the toner density is too low and the toner density is too low.
Therefore, the light amount UP process described below is performed (S31).
0). FIG. 8 is a view showing the toner path described in S310 of FIG.
FIG. 7 is a diagram for explaining a light amount UP process for increasing the density of a switch.
is there. In FIG. 8, the vertical axis is measured by a density sensor.
The relative density value of the toner patch obtained, the horizontal axis is the image reading part
The density of the density patch on the fixed paper read using
It shows the degree. The solid line in the figure indicates the first “PG copy”
Between the density measurement value of the toner patch and the curve
The second "PG copy" after the
-"Represents a curve connecting the measured density values. Density measurement by the first "PG copy"
The value is such that the density of the first level toner patch is Radc1,
The density of the patch is IIT1, and the toner patch of the second level is
Switch density is Radc2, density patch density is IIT2
And the density of the third level toner patch is Radc3,
The density of the density patch is IIT3. Meanwhile, the density patch
Is the IIT target value, the first target concentration
Any of the first to third levels measured by "PG copy"
Is smaller than the desired target concentration (IIT target value)
Calculates the density target value (Radc target value) of the toner patch.
I can't get it out. Therefore, the control unit determines the light intensity.
Change the light intensity set by the
Amount UP processing) and toner based on the changed light intensity
A patch is formed on the photosensitive drum, and the second “PG
Do "pee". Density measurement by the second "PG copy"
The value is such that the density of the first level toner patch is Radc11,
The density of the density patch is IIT11, and the second-level toner
-Patch density is Radc12, density patch density is I
IT12, the density of the third-level toner patch is Ra
dc13, the density of the density patch is IIT13. this
In such a case, make the exposure intensity sufficiently large by the control unit.
Since it is changed, the desired target concentration (IIT target value)
Within the range of the density measurement value by the second "PG copy"
Fits. Here, the IIT target value is the third level density parameter.
The density of the second level, which is lower than the switch density IIT13.
The concentration is higher than the concentration IIT12. Therefore, the description of S307 in FIG.
The density of the second level toner patch is calculated by the same formula as
Radc12 and the density target value of the toner patch (Radc
The difference ΔRadc from the standard value is calculated, and described in S308.
According to the same calculation formula as the above, the density target value (R
adc target value). Here, Ra in the calculation formula described in S307 is used.
Substitute Radc13 for dc3 and Radc12
Is substituted for Radc12. As described above, the light intensity with the fast response is changed.
Density patch of the desired target density
Drive the dispense motor to develop toner
Replenish in the container and mix with toner by stirring with auger
Ratio, increase the toner density, and then
It can be processed in a very short time than increasing the degree value
You. FIG. 9 is a diagram showing the toner particles described in S305 of FIG.
For explaining the light amount DOWN processing for lowering the switch density.
FIG. In FIG. 9, the vertical axis is measured by a density sensor.
The relative density value of the toner patch obtained, the horizontal axis is the image reading part
The density of the density patch on the fixed paper read using
Represents a degree value. The solid line in the figure indicates the first “PG copy”
Between the density measurement value of the toner patch and the curve
The second "PG copy" after the
-"Represents a curve connecting the measured density values. Density measurement by the first "PG copy"
The value is such that the density of the first level toner patch is Radc1,
The density of the patch is IIT1, and the toner patch of the second level is
Switch density is Radc2, density patch density is IIT2
And the density of the third level toner patch is Radc3,
The density of the density patch is IIT3. Meanwhile, the density patch
Is the IIT target value, the first target concentration
Any of the first to third levels measured by "PG copy"
Is also higher than the desired target concentration (IIT target value),
Calculating a density target value (Radc target value) of the toner patch
I can't. Therefore, the control unit sends the light intensity determination unit
Light intensity set to a predetermined intensity (light intensity D
OWN processing) and the toner based on the changed exposure light
A patch is formed on the photosensitive drum, and the second “PG
Do "pee". Second-time “PG copy” density measurement
The value is such that the density of the first level toner patch is Radc11,
The density of the density patch is IIT11, and the second-level toner
-Patch density is Radc12, density patch density is I
IT12, the density of the third-level toner patch is Ra
dc13, the density of the density patch is IIT13. this
In such a case, make the exposure intensity sufficiently small by the control unit.
Since it is changed, the desired target concentration (IIT target value)
Within the range of the density measurement value by the second "PG copy"
Fits. Here, the IIT target value is the third level density parameter.
The density of the second level, which is lower than the switch density IIT13.
The concentration is higher than the concentration IIT12. Therefore, the description of S304 in FIG.
In the same manner as described above, the density Ra of the second-level toner patch
dc12 and the toner patch density target value (Radc target
Value) and the difference ΔRadc from
According to the same calculation formula as above, the density target value (Ra
dc target value). Note that Ra in the calculation formula described in S307 is used.
Substitute Radc13 for dc3 and Radc12
Is substituted for Radc12. As described above, the light intensity with the fast response is changed.
As a result, a density patch of a desired target density can be obtained at a stretch,
By printing out using the whole image etc.
Low toner mixing ratio in developing unit by consuming a large amount of toner
And lower the toner density before adjusting the toner patch density value.
Processing can be performed in a much shorter time than lowering. As described above, the image form of the present invention is
According to the forming apparatus, in the density adjustment, the toner is fixed on the paper.
Density when the density range of the density patch deviates from the target density.
Adjustment by conventional toner consumption and toner replenishment
Changed the method to change the exposure intensity of the exposure equipment
Therefore, the responsiveness increases and the setting time of the concentration target value is shortened.
be able to.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flowchart for setting a target concentration value in the technique disclosed in Japanese Patent Application Laid-Open No. 11-174748. FIG. 2 is an explanatory diagram of a specific method of determining a density target value in the technology disclosed in Japanese Patent Application Laid-Open No. 11-174748. FIG. 3 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. FIG. 4 is a diagram showing an operator operation procedure when determining a density target value in the embodiment. FIG. 5 is a flowchart illustrating a processing procedure of a “PG copy” program in the embodiment. FIG. 6 is a diagram illustrating a density patch. FIG. 7 is a flowchart showing a processing procedure of a “IIT measurement” program in the embodiment. 8 is a diagram for explaining a light amount UP process for increasing the density of a toner patch described in S310 of FIG. 7; FIG. 9 is a diagram for explaining a light amount DOWN process for reducing the density of the toner patch described in S305 of FIG. 7; [Description of Signs] 1 Document 2 Platen 3 Exposure lamp 4 Scanning optical system 5 CCD sensor 6 Image memory 7 Image processing unit 8 Laser exposure unit 8a Light emission driver 8b Semiconductor laser 9 Polygon mirror 10 Photoconductor drum 11 Charger 12 Developing unit 13 Transfer unit 14 Density sensor 15 Cleaner 16 Static eliminator 17 Bias voltage applying unit 18 Toner box 19 Motor driver 20 Dispense motor 21 Paper feed roll 22 Transport guide 23 Fixing unit 24 Discharge roll 25 Tray 26 Control unit 27 Patch data memory 28 Light intensity determination Unit 29 transfer position 30 density patch 30a density patch 30b corresponding to the first level density patch 30c corresponding to the second level density patch 34 corresponding to the third level 34 comparing unit 35 image reading unit

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Toru Iwanami             2274 Hongo, Ebina-shi, Kanagawa Fuji Zero             Co., Ltd. Ebina Office F term (reference) 2H027 DA09 DA10 DB01 DE02 DE07                       DE10 EA02 EA05 EA06 EB01                       EC07 EC10 ED06 ED09 ED10                       EE01 HB04 HB06 ZA07                 2H076 AB05 DA05 DA08 DA21                 2H077 AA11 AA15 AB02 AB14 AD06                       AD36 DA04 DA08 DA47 DB01                       DB08 DB13 EA03 GA04

Claims (1)

Claims: 1. An electrostatic latent image is formed by irradiating exposure light onto an image carrier, and a toner image is formed by applying toner to the electrostatic latent image. Finally, in an image forming apparatus for transferring and fixing on a recording medium to form an image composed of a fixed toner image on the recording medium, a plurality of toner patches having different densities are formed, and the plurality of toner patches are finally formed. A patch forming unit that forms a plurality of density patches composed of toner patches fixed on the recording medium by transferring and fixing the recording medium on the recording medium; A density sensor that obtains first density data representing the density of the plurality of toner patches by measuring the density of the plurality of toner patches; and a density sensor formed on a recording medium by the patch forming unit. A density data acquisition unit that acquires second density data representing the densities of the plurality of density patches obtained by the density measurement of the plurality of density patches; and a first density data obtained by measurement by the density sensor and the density data acquisition unit. A density control unit that adjusts image forming parameters that affect the density of an image formed on a recording medium based on a relationship with the second density data acquired by the density data acquisition unit; When any of the second density data acquired by the density data acquisition unit is larger than a predetermined target density, or when any of the second density data is smaller than the target density, An image forming apparatus, wherein a plurality of toner patches and a plurality of density patches are formed again by adjusting the amount of exposure light applied to an image carrier.