JP3491915B2 - Image forming device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus capable of executing an electrophotographic process, and in particular, an image is formed by scanning an image of a light beam based on an image signal obtained by reading an original image on a photosensitive member. The present invention relates to an image forming apparatus.

[0002]

2. Description of the Related Art An image forming apparatus capable of executing an electrophotographic process, for example, a copying apparatus has an image output characteristic as shown in FIG.

FIG. 16 is a diagram showing the electrophotographic characteristics in this type of image forming apparatus, the vertical axis representing copy density (Copy.D).
ensity), and the horizontal axis shows the document density (Org. Density).

The characteristics shown in this figure are mainly determined by the photosensitive characteristics of the photosensitive member and the developing characteristics of the developer using toner, and are essential to electrophotographic technology. In the digital electrophotographic copying apparatus, by electrically correcting the image data, it is possible to obtain a free image output characteristic without being influenced by the electrophotographic characteristic. For this correction, a lookup table method is usually adopted. In this method, a reference table for changing the value of the input image signal to another value in accordance with the characteristics on the output side (for example, electrophotographic characteristics) is created in advance. The input data can be changed according to the output characteristics.

However, it is known that an electrophotographic output device cannot always maintain the same image due to a change with time. This is because the photoconductor and the material device such as the toner change with time, and various control methods are adopted for the correction.

Particularly in a digital type copying apparatus, an output image is read by a reader unit, the read data is analyzed, and it is determined whether or not an output image according to an image density signal is obtained. If there is a difference in image density, the image forming conditions are corrected and set so as to cancel the difference.

FIG. 17 and FIG. 18 are diagrams showing electrophotographic characteristics in this type of image forming apparatus.
The vertical axis represents the image density, and the horizontal axis represents the contrast potential. Further, in FIG. 18, the vertical axis represents the contrast potential and the horizontal axis represents the grid bias potential.

[0008]

In such an image forming apparatus, according to the correction setting control of the image forming conditions, it is premised that the change in the image forming conditions behaves in substantially the same manner in all the apparatuses. There is. However, the electrophotographic image forming apparatus includes a charging device for charging the photoconductor, and, for example, a coroton (is a scorotron).
When the height of the charging wire of the charger is changed by, for example, 1 mm, the electrophotographic characteristic shown in FIG. 18 has a characteristic that it easily changes as shown in FIG. Further, although typical changes over time can be considered in advance, it is practically impossible to deal with changes over time that meet the usage conditions of all devices.

Further, when the cause of the change in the image density is investigated, it is a phenomenon that the respective image forming conditions appear intricately intertwined with each other. Therefore, it is necessary to specify which image forming condition causes the image quality deterioration. Is even more difficult. Therefore, the correction of the image forming condition according to the preset condition may cause an error such that the image quality is erroneously deteriorated or no effect is recognized, contrary to the image quality improvement.

Further, in an image forming apparatus using a semiconductor laser as an exposure light source, the rising characteristics of the laser beam and the diameter of the laser beam spot also change with the lapse of time, so that the initial state at the time of factory shipment, etc. There is a problem that it is very difficult to maintain the same exposure condition as the above.

The present invention has been made to solve the above problems , and a predetermined inspection pattern image is formed on a photoconductor.
It is possible to form it repeatedly multiple times, and
When multiple images are repeatedly formed,
Set the image forming conditions, and under different image forming conditions
Predetermined inspection pattern image is repeated multiple times on the photoconductor
After being formed, a predetermined inspection pattern formed on the recording medium
Scan the image and the image based on this read data
By correcting the forming conditions, the original placed on the platen
Optically reads the draft image and outputs the read image signal
Converted to an image signal and based on the converted output image density signal
The modulated light beam is scanned and imaged on the photoconductor,
The developed image by developing the electrostatic latent image formed on the photoconductor
In an image forming apparatus configured to form the on a recording medium,
The specific image forming condition on individual devices, and to provide an image forming apparatus capable of correcting the short One or optimal.

[0012]

An image forming apparatus according to the present invention comprises an image reading means for optically reading a document image placed on a document table, and an image signal read by the image reading means as an output image. and an image signal conversion table for converting into a signal, and the image writing means for scanning and imaging the modulated light beam onto a photosensitive optical body based on the converted output image density signal by the image signal conversion table, the image writing means A developing means for developing the electrostatic latent image formed on the photoconductor by the recording means, and an image developed by the developing means.
And forming means for forming on the medium, a pattern generating means for image density to generate a test pattern image signal representing a predetermined test pattern image is displaced in stages, with the test pattern image signal generated from said pattern generating means On the basis of
Tomo repeatedly formed allowed to several times the predetermined test <br/>査pattern image on said photosensitive member by said image writing means
In addition, the predetermined inspection pattern image is repeatedly formed a plurality of times.
And when the, a condition setting means for setting a plurality of different image forming condition, said predetermined inspection path on the photosensitive member under a plurality of different image forming conditions set by said condition setting means
After the turn image is repeatedly formed a plurality of times, the predetermined inspection pattern image formed on the recording medium is read by the image reading unit, and the correction is performed to correct the image forming condition based on the read data. And means.

[0013] In addition, the condition setting means, said developing means
The image forming conditions are set by changing the developing bias of the above.

Furthermore, the condition setting means is for the said potential of the charged photosensitive member by changing the developing bias of the developing unit configured to set different image forming conditions.

Further, the condition setting means is configured to set different image forming condition by changing the image signal conversion table.

Furthermore, the condition setting means is configured to set the image signal conversion table between the developing bias and the change is allowed by different image forming condition of said developing means.

Further, the condition setting means is configured to set the developing bias and the photosensitive member charge potential and changing the in different image forming conditions of the developing means and the image signal conversion table.

Furthermore, the condition setting means is configured to set the image writing means of the light beam different imaging conditions by changing the amount of light emitted.

Further, the condition setting means is configured to set the image signal conversion table and the image writing means of the light beam emitting amount and the change is allowed by different imaging conditions.

Furthermore, the condition setting means, by changing the amount of light emitted from the light beam of the charging potential and the writing means of the sensitive <br/> optical member and the developing bias of the developing unit and the image signal conversion table The configuration is such that different image forming conditions are set.

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 is a cross-sectional view of an essential part for explaining the configuration of an image forming apparatus showing a first embodiment of the present invention.
A digital copying machine capable of executing an electrophotographic process,
It is composed of a reader unit and a printer unit, and corresponds to the case where the reader unit and the printer unit execute the image forming sequence while communicating with each other.

In the figure, reference numeral 1 denotes a document illuminating device, which is provided with a scanning member provided with, for example, a halogen lamp, and illuminates the document according to the movement of the scanning member. An optical system 2 projects an original image on an image reading sensor 3 such as a CCD. In this embodiment, the image reading sensor 3 reads an image with a resolution of 400 to 600 DPI and converts it into, for example, an 8-bit digital image signal. That is, the image can be read in 256 gradations. Reference numeral 4 is a lookup table (LU) for converting the read image signal and the output image signal.
T) and 5 are laser driver circuits which drive the semiconductor laser unit 6 according to a digital image signal. The laser light emitted from the semiconductor laser of the semiconductor laser unit 6 is deflected by the rotary polygon mirror 7 and is applied to the photosensitive drum 9 via the mirror 8. An electrophotographic image forming unit 10 includes a developing device 11 and a fixing device 12.
An image signal generator 13 is configured to generate any image signal in any pattern. Reference numeral 14 is a developing bias power source, and 15 is an 8-bit D / A converter for controlling the output value of the power source. A primary charger 16 uniformly charges the surface of the photosensitive drum 9. A controller 17 includes a CPU, a ROM, and a RAM, and controls the image forming sequence and the image forming condition setting sequence as a whole.

As an image forming condition in this embodiment, first, in the dark portion potential, the surface potential of the photosensitive drum 9 is uniformly charged to −700 V by the primary charger. The conditions for the exposure by the semiconductor laser are adjusted so that the data of FFh in the image portion potential is −200V. At this time, the digital value of the developing bias before D / A conversion was 80 h. The digital value of this phenomenon bias is 5V / 1 bit (bit), but 0V to
It is configured to be able to control up to -900V.

In the image forming apparatus thus constructed, when the semiconductor laser unit 6 forms an inspection pattern image on the photosensitive drum 9 based on the inspection pattern image signal generated by the image signal generating device 13, a controller is formed. After 17 sets a plurality of different image forming conditions, the inspection pattern image formed on the recording medium is read by the image reading sensor 3, and the controller 17 corrects the set image forming condition from the read data. Since the inspection pattern images corresponding to different image forming conditions are read, the image forming state caused by the complex image forming conditions that cannot be analyzed by the predetermined inspection pattern image reading can be easily grasped, and the set image forming conditions can be optimized. It is possible to correct the state in a short time.

Further, the controller 17 includes the developing device 11
Since different image forming conditions are set by changing the potential of the developing bias power source 14 that determines the developing bias of the above, it is necessary to grasp the image forming state caused by the setting state of the developing bias that is difficult to analyze by reading a predetermined inspection pattern image. Is possible.

Further, since the controller 17 sets different image forming conditions by changing the charging potential of the photosensitive drum 9 and the developing bias of the developing device 11, the developing bias and the photosensitive voltage which are difficult to analyze by reading a predetermined inspection pattern image. It is possible to grasp the image forming state caused by the setting state with the charging potential of the drum 9.

Further, since the controller 17 changes the LUT 4 and sets different image forming conditions, it is possible to grasp the image forming state due to the setting state of the LUT 4 which is difficult to analyze by reading a predetermined inspection pattern image. Become.

Further, since the controller 17 changes the LUT 4 and the developing bias of the developing device 11 to set different image forming conditions, the setting state of the LUT 4 and the setting of the developing bias which are difficult to analyze by reading a predetermined inspection pattern image. It is possible to grasp the image forming state caused by the state.

Since the controller 17 sets different image forming conditions by changing the developing bias of the LUT 4, the developing device 11 and the charging potential of the photosensitive drum 9, the LUT which is difficult to analyze by reading a predetermined inspection pattern image.
4 setting state, developing bias setting state, and photosensitive drum 9
It is possible to grasp the image forming state due to the setting state of the charging potential of the above.

Further, since the controller 17 changes the light emission amount of the light beam of the semiconductor laser unit 6 to set different image forming conditions, the light beam of the semiconductor laser unit 6 which is difficult to analyze by reading a predetermined inspection pattern image. It is possible to grasp the image forming state caused by the setting state of the emitted light amount.

Since the controller 17 sets different image forming conditions by changing the light emission amount of the light beam of the LUT 4 and the semiconductor laser unit 6, the controller 17 of the semiconductor laser unit 6 which is difficult to analyze by reading a predetermined inspection pattern image. It is possible to grasp the image forming state caused by the setting state of the light emission amount of the light beam and the setting state of the LUT 4.

Further, the controller 17 sets different image forming conditions by changing the developing bias of the developing device 11, the developing bias of the developing device 11, the charging potential of the photosensitive drum 9 and the light emission amount of the light beam of the writing means, so that a predetermined inspection is performed. Semiconductor laser unit 6 that is difficult to analyze by reading pattern images
It is possible to grasp the image forming state resulting from the setting state of the emitted light amount of the light beam, the setting state of the developing bias of the developing device 11, the setting state of the LUT 4, and the setting state of the charging potential of the photosensitive drum 9.

In the present embodiment, the case where the image writing means is composed of the semiconductor laser unit 6 has been shown, but it is also applicable to an image forming apparatus in which the image writing means is composed of a liquid crystal shutter or an LED head. Further, the gradation control of the output image signal is based on the area gradation control in the pulse width modulation control method in this embodiment, but other methods may be used.

FIG. 2 shows the image signal generator 1 shown in FIG.
It is a figure which shows an example of the 1st inspection pattern image in which 3 can occur.

As shown in this figure, the inspection pattern image is divided into three stages, each consisting of white, black and three types of halftones. The apparatus of this embodiment stores image data as 8-bit data. The image signal has 255 gradations from 00h to FFh. The halftones in the inspection pattern are 40h, 80h, and C0h. In addition,
The reason why the pattern is divided into three stages in this embodiment is that the developing bias values (DC values) are different, and the respective digital values are 76h (-550V) and 80h.
(-600V) and 8Ah (-650V).

Next, when the output inspection pattern image output shown in FIG. 2 is placed at a predetermined position of the reader unit and image reading is started, a reading result as shown in FIG. 3 is obtained. [Second Embodiment] FIGS. 3 and 4 are diagrams showing image density data for the inspection pattern image shown in FIG. 2, in which the vertical axis represents the image density and the horizontal axis represents the image density data value.

For example, after the image density data values shown in FIG. 3 have been obtained, when 10,000 copies are made and then the reading result for the inspection pattern image is also examined, the image density data values shown in FIG. 4 change. This is because the image density is reduced by the sensitivity change of the photosensitive drum 9 due to the development processing of 10,000 sheets. This decrease in density is 0.05 for the data of "80h", so the result of setting the developing bias to "86h" in the initial data is correct, but it should be set to "88h" correctly. What must be done is clear from FIG.

In this way, the image forming conditions are automatically corrected while the image inspection pattern images corresponding to various image forming conditions as shown in FIG. 2 are formed on the photosensitive drum 9 and read, and as shown in FIG. In addition, the density reproduction characteristic d according to the present embodiment is in a state of following the density reproduction characteristic a at the time of substantially initial setting even after the copying of 20,000 sheets is completed.

FIG. 6 is a diagram for explaining the density reproduction characteristics in the image forming apparatus according to the present invention, in which the vertical axis represents the output image density and the horizontal axis represents the original image density.

In the figure, b and c show the density reproduction characteristic state by the conventional image forming condition correction after the copying of 20,000 sheets, which corresponds to the state in which the image forming condition is considerably deviated from the density reproduction characteristic a. To do.

In the above embodiment, the case where the developing bias in the image forming condition is corrected to control so as to maintain the density reproduction characteristic a has been described. However, when the image density becomes too thin, the developing bias is limited. I will raise it without saying. Therefore, when the developing bias is increased by about 80 V, the potential approaches the dark portion potential of the image, and fogging occurs in the white background portion. In order to prevent such fog, the image forming condition setting control can be performed in a state where the difference between the dark portion potential (grid bias potential) and the developing bias potential is held constant as shown in FIG. FIG. 8 corresponds to the inspection pattern image (second inspection pattern image) in the state where the difference from the developing bias potential is kept constant. For example, the image density at 80 h of the halftone in the inspection pattern is substantially the developing bias. The image density can be corrected by changing it by 100 V or more, and the fog on the white background portion did not occur.

It should be noted that, with the passage of time, particularly the image forming state changes within one day depending on the weather state (humidity, temperature, etc.),
Therefore, as will be described later, the inspection pattern formed by changing the developing bias condition may be read, and the gradation characteristic, that is, the characteristic of the look-up table may be corrected according to the result. [Third Embodiment] FIG. 9 is a diagram showing characteristics of a look-up table in the image forming apparatus according to the present invention, in which the horizontal axis represents the input density and the vertical axis represents the output density.

In the figure, (a) is a reference look-up table. The look-up table (b) is a table in which the characteristics of the look-up table (a) are corrected in the direction of slightly increasing the density. It is the look-up table (c) that is corrected in the direction to suppress it.

FIG. 10 is a diagram showing an example of a third inspection pattern image that can be generated by the image signal generator 13 shown in FIG. 1, and the relationship with the selected look-up table under a constant developing bias. Indicates.

As shown in this figure, the inspection pattern image formed while changing the developing bias as shown in FIG. 2 is read by the image reading sensor 3 shown in FIG. 1, and the optimum is read based on the read data. Any one of the lookup tables (a) to (c) for maintaining the gradation reproduction characteristic is selected.

As a result, the gradation reproduction characteristics, which are slightly deviated due to the effects of the difference in the morning and the difference in temperature and humidity, can be set to the optimum state at all times, and the optimum image can be obtained by following the subtle environmental fluctuations during the day. Formation conditions can be set.

In the above second and third embodiments, the case where the image inspection pattern is formed while individually changing the image forming conditions has been described. For example, as shown in FIG. 11, the difference between the grid bias and the developing bias is shown. May be changed while keeping constant, and the image inspection pattern may be formed while simultaneously changing the characteristics of the look-up table that determines the gradation reproducibility. [Fourth Embodiment] FIG. 11 is a diagram showing an example of a fourth inspection pattern image that can be generated by the image signal generator 13 shown in FIG. 1, while keeping the difference between the grid bias and the developing bias constant. This corresponds to the case where the image inspection pattern is formed while changing the characteristics and simultaneously changing the characteristics of the look-up table (LUT) 4 that determines the gradation reproducibility.

As described above, the image inspection pattern is formed by changing the difference between the grid bias and the developing bias while keeping it constant and simultaneously changing the characteristics of the lookup table that determines the gradation reproducibility. As shown in FIG. 12, simply selecting the selected lookup table 4 under a constant developing bias causes a change over time, that is, after the initial image, for example, a slight deviation occurs in the gradation reproducibility of the 10000th sheet. (In the figure, the output image density is deviated between the image density data “40h” and “C0h”). This is because the sensitivity characteristic of the photosensitive drum 9 shown in FIG. 1 changes as shown in FIG.

FIG. 13 is a diagram showing the sensitivity characteristic of the photosensitive drum 9 in FIG. 1, in which the vertical axis represents the potential of the photosensitive drum 9 and the horizontal axis represents the exposure amount.

As shown in this figure, when image formation is performed on, for example, about 10,000 sheets, the charging potential of the photosensitive drum 9 changes, and the attenuation amount of the potential with respect to a constant light amount changes. Therefore, as shown in FIG. 12, while the difference between the grid bias and the developing bias is kept constant, the image inspection pattern is formed while simultaneously changing the characteristics of the lookup table that determines the gradation reproducibility. ,
It is possible to select and set the optimum image forming condition from the read data.

In the above embodiment, it was necessary to correct the attenuation characteristic by changing the charge amount of the photosensitive drum 9, but as will be described later, a semiconductor laser which serves as an image drawing means of a laser beam printer. The inspection pattern image may be formed while changing the drive current applied to the device under a constant developing bias. [Fifth Embodiment] FIG. 14 is a diagram showing an example of a fifth inspection pattern image that can be generated by the image signal generator 13 shown in FIG. 1, and is the image drawing means of the laser beam printer shown in FIG. This corresponds to the case where the inspection pattern image is formed while the drive current applied to the semiconductor laser 6 is changed under a constant developing bias.

As shown in the figure, after the inspection pattern image is formed while changing the drive current applied to the semiconductor laser 6 serving as the image drawing means of the laser beam printer under a constant developing bias, this image formation is performed. By reading the image with the image reading sensor 3 and determining the developing bias and the laser beam drive current at the same time, the laser drive current change is also corrected without considering the attenuation characteristics of the photosensitive drum 9. It became possible.

[0062]

As described above , according to the present invention,
Predetermined inspection pattern image is repeated multiple times on the photoconductor
In addition to completing the test, a predetermined inspection pattern image is made multiple times.
Set multiple different image forming conditions for repeated formation
However, if a predetermined number of different image forming conditions are set on the photoreceptor,
Recording after the inspection pattern image is repeatedly formed multiple times
Read a predetermined inspection pattern image formed on the medium
The image forming conditions based on this read data
Therefore, without performing the image forming operation multiple times,
Multiple image forming conditions with one image forming operation
By forming a predetermined inspection pattern image multiple times by
Under multiple different image forming conditions.
By reading the inspection pattern image
The optimum image forming conditions for each device can be
Can be corrected in between.

Further, the condition setting means sets different image forming conditions by changing the developing bias of the developing means. Therefore, the image forming state caused by the setting state of the developing bias which is difficult to analyze by reading a predetermined inspection pattern image is set. You can figure it out.

Further, since the condition setting means sets different image forming conditions by changing the charging potential of the photoconductor and the developing bias of the developing means, the developing bias and the photoconductor which are difficult to analyze by reading a predetermined inspection pattern image. It is possible to grasp the image forming state caused by the setting state with the charging potential of.

Further, since the condition setting means changes the image signal conversion table and sets different image forming conditions,
It is possible to grasp the image forming state due to the setting state of the image signal conversion table which is difficult to analyze by reading a predetermined inspection pattern image.

Further, since the condition setting means sets different image forming conditions by changing the image signal conversion table and the developing bias of the developing means, the setting of the image signal conversion table which is difficult to analyze by reading a predetermined inspection pattern image. The image forming state caused by the state and the setting state of the developing bias can be grasped.

Further, since the condition setting means sets different image forming conditions by changing the image signal conversion table, the developing bias of the developing means and the charging potential of the photoconductor, it is difficult to analyze by reading a predetermined inspection pattern image. It is possible to grasp the image forming state caused by the setting state of the image signal conversion table, the setting state of the developing bias, and the setting state of the charging potential of the photoconductor.

Further, since the condition setting means sets different image forming conditions by changing the light emission amount of the light beam of the image writing means, the light emission of the light beam of the image writing means which is difficult to analyze by reading a predetermined inspection pattern image. It is possible to grasp the image forming state caused by the setting state of the light amount.

Further, since the condition setting means sets different image forming conditions by changing the image signal conversion table and the light emission amount of the light beam of the image writing means, image writing which is difficult to analyze by reading a predetermined inspection pattern image. It is possible to grasp the image forming state caused by the setting state of the light emission amount of the light beam of the means and the setting state of the image signal conversion table.

Further, the condition setting means sets different image forming conditions by changing the image signal conversion table, the developing bias of the developing means, the charging potential of the photoconductor, and the light emission amount of the light beam of the writing means. Due to the setting state of the light emission amount of the light beam of the image writing unit, the setting state of the developing bias of the developing unit, the setting state of the image signal conversion table, and the setting state of the charging potential of the photoconductor, which are difficult to analyze by reading the inspection pattern image of The formed image forming state can be grasped.

Therefore, the image forming condition peculiar to each device can be optimized and can be corrected in a short time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts for explaining the configuration of an image forming apparatus showing a first embodiment of the present invention.

FIG. 2 is a diagram showing an example of a first inspection pattern image that can be generated by the image signal generating device shown in FIG.

FIG. 3 is a diagram showing image density data for the inspection pattern image shown in FIG.

4 is a diagram showing image density data for the inspection pattern image shown in FIG.

5 is a diagram showing image density data for the inspection pattern image shown in FIG.

FIG. 6 is a diagram illustrating density reproduction characteristics in the image forming apparatus according to the present invention.

FIG. 7 is a diagram showing image density characteristics in the image forming apparatus according to the present invention.

8 is a diagram showing an example of a first inspection pattern image that can be generated by the image signal generating device shown in FIG.

FIG. 9 is a diagram showing characteristics of a look-up table in the image forming apparatus according to the present invention.

10 is a diagram showing an example of a third inspection pattern image that can be generated by the image signal generating device shown in FIG.

FIG. 11 is a diagram showing a fourth inspection pattern image example that can be generated by the image signal generating device shown in FIG. 1.

FIG. 12 is a diagram illustrating density reproduction characteristics in the image forming apparatus according to the present invention.

FIG. 13 is a diagram showing sensitivity characteristics of a photosensitive drum in FIG.

14 is a diagram showing a fifth inspection pattern image example that can be generated by the image signal generating device shown in FIG.

FIG. 15 is a diagram showing a laser drive current variation characteristic in the image forming apparatus according to the present invention.

FIG. 16 is a diagram showing electrophotographic characteristics in this type of image forming apparatus.

FIG. 17 is a diagram showing electrophotographic characteristics in this type of image forming apparatus.

FIG. 18 is a diagram showing electrophotographic characteristics in this type of image forming apparatus.

FIG. 19 is a diagram showing electrophotographic characteristics in this type of image forming apparatus.

[Explanation of symbols]

4 Look-up table (LUT) 5 Laser driver circuit 13 Image signal generator 14 Development bias power supply 17 Controller

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification symbol FI G03G 15/06 101 (56) References JP-A-63-31355 (JP, A) JP-A-1-261669 (JP, A) JP-A-1-261668 (JP, A) JP-A-1-261670 (JP, A) JP-A-62-291265 (JP, A) JP-A-3-271766 (JP, A) JP-A-3-256067 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04N 1/23-1/31

Claims (9)

(57) [Claims] And 1. A image reading means for reading a document placed on the image on the document table to optically, an image signal conversion table for converting an image signal by the image reading means has read the output image signal, the image signal conversion image writing means for scanning and imaging the modulated light beam on the basis of the output image density signal converted by the table on the sensitive light body, the electrostatic latent image formed on said photosensitive member by said image writing means Developing means for developing and an image developed by the developing means is formed on a recording medium.
And a predetermined inspection pattern image in which the image density is gradually changed.
Inspection and pattern generating means for generating a pattern image signal, said pattern generating means forms a plurality of times said predetermined test pattern image on said photosensitive member by said image writing means based on the test pattern image signal generated from the representative
In addition to the completion of the
And when the number of times repeatedly formed, a condition setting means for setting a plurality of different image forming condition, the predetermined test pattern image on the photosensitive member under a plurality of different image forming conditions set by said condition setting means
After the image has been repeatedly formed a plurality of times, reading the predetermined test pattern image formed on a recording medium by the image reading means, having a correction means for correcting an image forming condition, a based on the read data An image forming apparatus characterized by. 2. The image forming apparatus according to claim 1, wherein the condition setting unit sets different image forming conditions by changing a current image bias of the developing unit . Wherein said condition setting means, the photoconductor charging potential and the developing unit of the developing bias and an image forming apparatus according to claim 1, wherein setting the change is allowed by different imaging conditions. Wherein said condition setting means, the image forming apparatus according to claim 1, wherein the setting the image signal to the conversion table is changed in different imaging conditions. Wherein said condition setting means, the image forming apparatus according to claim 1, wherein the setting the image signal conversion table between the developing bias and changing the in different image forming condition of said developing means. Wherein said condition setting means, according to claim 1, characterized in that to set the image signal conversion table and the developing bias and the photosensitive member charge potential and changing the in different image forming condition of said developing means The image forming apparatus described. Wherein said condition setting means, the image forming apparatus according to claim 1, wherein by changing the emission intensity of the light beam and sets the different image forming conditions of the image writing means. Wherein said condition setting means, image according to claim 1, wherein the setting the image signal conversion table and the image writing means of the light beam emitted light amount and changing the in different image forming conditions Forming equipment. Wherein said condition setting means, said image signal conversion table and the developing bias and the photosensitive member charge potential and the writing means of the light beam emitting amount and the change is allowed by different image forming condition of said developing means The image forming apparatus according to claim 1, wherein the image forming apparatus is set.