JP2008179019A - Image forming apparatus and image forming system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect with good precision unevenness in the main scanning direction generated in an image forming apparatus without any help from others. <P>SOLUTION: The image forming apparatus is equipped with an image forming part 14 and an image reading part 15. The image reading part 15 is equipped with a line sensor arranging an imaging element in the conveying direction of paper, and moves this in the direction of intersecting at right angles to the conveying direction of the paper. By doing so, as the main scanning direction of the image forming part 14 (exposure apparatus) and the main scanning direction of the image reading part 15 (line sensor) intersect at right angles each other, it is possible to acquire image data hardly influenced by the noises caused by the line sensor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and an image forming system.

  In an image formed by the image forming apparatus, density unevenness (non-uniformity) may occur in a predetermined direction. For example, in an electrophotographic image forming apparatus, it is known that unevenness is likely to occur in the exposure scanning direction (main scanning direction). In addition, in order to detect and correct such unevenness, there is a technique of optically reading the formed image when it is being conveyed and performing correction according to the reading result (for example, Patent Documents). 1). When reading an image in this way, it is common to use a line-shaped image reading device having the same width as the image or paper, and read the entire image or paper while transporting it to other transport means. is there.

  However, such a line-shaped image reading apparatus is generally composed of a plurality of imaging elements, and the characteristics of each element vary, so that the reading characteristics are also non-uniform. Therefore, when it is attempted to measure the unevenness of the image in the main scanning direction with such a configuration, the unevenness due to the image reading device itself is superimposed on the unevenness of the image itself in the reading result of the image reading device. As a result, there is a problem that the unevenness of the image cannot be accurately measured and appropriate correction cannot be performed.

There are technologies described in Patent Documents 2 and 3 that focus on such problems. However, these techniques have a problem in that an image must be read manually.
JP 2005-208364 A JP 2001-105697 A JP 2006-60713 A

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique capable of accurately detecting unevenness in the main scanning direction generated in the image forming apparatus without manual intervention. is there.

In order to achieve the above-described object, the present invention continuously forms an image having a predetermined width in the first direction of a sheet-like material on the sheet-like material based on supplied image data. An image forming unit, a conveying unit configured to convey a sheet-like object on which an image is formed by the image forming unit, along a second direction orthogonal to the first direction, and the conveying unit is conveying or conveying An image pickup means provided with a plurality of image pickup elements for generating an image signal obtained by picking up an image formed on the sheet-like object along the second direction of the sheet-like object, and the image pickup means in the second direction And an image forming apparatus including a moving unit that moves the image forming apparatus in a direction perpendicular to the image forming apparatus.
According to such an image forming apparatus, the main scanning direction of the image forming unit parallel to the first direction and the main scanning direction of the imaging unit parallel to the second direction are orthogonal to each other. Even when there is a variation in the main scanning direction, the image can be read without being affected by this.

  Further, in the image forming apparatus, the conveying unit may be configured to reduce a conveying speed of the sheet-like material or to stop conveying the sheet-like material when the imaging unit takes an image. . If it is the structure which stops conveyance of a sheet-like object, it will become possible to read a test image at a fixed speed irrespective of the width | variety of the sheet-like object in the 1st direction.

  In the image forming apparatus, the transport unit includes a transport path for the sheet-like material on which an image is formed by the image forming unit, a first transport path for guiding the sheet-like material to the imaging unit, and the first transport path. A configuration may be provided that includes route switching means for determining one of the second transport routes different from the one transport route.

  In the image forming apparatus, a supply unit that supplies image data to the image forming unit, and an extraction that extracts information about unevenness in the first direction of the image formed on the sheet-like material by the image forming unit. And correction means for correcting the image data supplied from the supply means to the image forming means in the first direction based on the information extracted by the extraction means, and the supply means includes the image Supplying image data representing a test image for detecting unevenness in the first direction, the imaging means generates an image signal representing the test image while being moved by the moving means, and the extracting means The information may be extracted based on an image signal representing the test image generated by the imaging unit.

  In addition, the present invention is an image forming system including an image forming apparatus and a control device that controls the image forming apparatus, and the image forming apparatus performs a first direction of a sheet-like material based on image data. An image forming unit that continuously forms an image having a predetermined width on the sheet-like material, and a sheet-like material on which an image is formed by the image forming unit is orthogonal to the first direction. Conveying means for conveying in the direction, and an image pickup device for generating an image signal obtained by imaging an image formed on the sheet-like material being conveyed or conveyed by the conveying means in the second direction of the sheet-like material Image data representing a test image for detecting unevenness in the first direction of the image, a plurality of imaging means provided along the moving means, a moving means for moving the imaging means in a direction orthogonal to the second direction, The picture An image generated by the imaging unit based on a test image formed by the image forming unit based on test image data supplied by the supplying unit. An image forming system comprising: an acquisition unit that acquires a signal; and an extraction unit that extracts information about unevenness in the first direction based on an image signal representing the test image acquired by the acquisition unit.

  According to the present invention as described above, unevenness in the main scanning direction generated in the image forming apparatus can be accurately detected without manual intervention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiment described below, image data is image data in a so-called RGB format, and 8 bits (256) for each color of R (red: red), G (green: green), and B (blue: blue). It is assumed that the pixel data has a gradation value of (gradation).

[Configuration of the embodiment]
FIG. 1 is a diagram showing an overall configuration of an image forming system 100 according to an embodiment of the present invention. As illustrated in FIG. 1, the image forming system 100 according to the present exemplary embodiment includes an image forming apparatus 10, a control apparatus 20, a client apparatus 30, and a network 40. The image forming apparatus 10 forms an image corresponding to the supplied image data on a sheet-like object such as paper. In the present embodiment, the image forming apparatus 10 is an electrophotographic printer. The control device 20 is a computer device that performs control for correcting unevenness that occurs in the image forming apparatus 10. The client device 30 is a computer device such as a personal computer, and supplies image data to be processed by the image forming apparatus 10. The network 40 is a communication network such as the Internet or a LAN (Local Area Network), for example, and connects the image forming apparatus 10 and the control apparatus 20 in a communicable manner.

  FIG. 2 is a block diagram illustrating a configuration of the image forming apparatus 10. As shown in FIG. 1, the image forming apparatus 10 includes a control unit 11, a storage unit 12, a communication unit 13, an image forming unit 14, and an image reading unit 15. The control unit 10 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The control unit 11 controls the operation of each unit of the image forming apparatus 10 by the CPU executing a program stored in the ROM or the storage unit 12 using the RAM as a work area. In addition, the control unit 11 performs various image processes on the image data. This image processing can be executed by the CPU described above, but it is more desirable to use a dedicated integrated circuit.

  The image processing executed by the control unit 11 includes image data correction processing using a lookup table. Here, the correction process is a process of converting the gradation value of each pixel data constituting the image data into a predetermined value corresponding to the gradation value. The set of predetermined values to be converted is a lookup table. In the present embodiment, the lookup table applied to the pixel data is different for each pixel data in the main scanning direction. This is to correct density unevenness in the main scanning direction that occurs in the image forming unit 14 using this lookup table.

The storage unit 12 is a storage device such as an HDD (Hard Disk Drive) and stores various data. The data stored in the storage unit 12 includes the above-described lookup table (LUT).
The communication unit 13 is an interface device for exchanging information via the network 40. The communication unit 13 obtains image data and an instruction regarding image formation via the network 40 and supplies them to the control unit 11.

The image forming unit 14 forms an image corresponding to the supplied image data on a sheet-like material such as paper. The sheet-like material may be made of a material different from paper (for example, plastic).
FIG. 3 is a diagram illustrating main configurations of the image forming unit 14 and the image reading unit 15. As shown in the figure, the image forming unit 14 includes a transfer unit 141Y, 141M, 141C and 141K, an intermediate transfer belt 142, a transfer roll 143, a fixing device 144, a plurality of transport rolls 145, and a path switching member. 146, a first tray 147, and a second tray 148. Note that a one-dot chain line in the figure indicates a sheet conveyance path.

  The transfer units 141Y, 141M, 141C, and 141K each include a photosensitive drum, a charging member, an exposure device, a developing device, and a transfer member. Each of the transfer units 141Y, 141M, 141C, and 141K forms an electrostatic latent image by exposing and scanning the charged photosensitive drum with a laser beam corresponding to the image, and developing this with toner. Then, the image is transferred (primary transfer) to the intermediate transfer belt 142. The transfer units 141Y, 141M, 141C, and 141K form yellow (Y), magenta (M), cyan (C), and black (K) toner images, respectively.

  The photosensitive drums of the transfer units 141Y, 141M, 141C, and 141K each have a predetermined width in a direction perpendicular to the paper surface of FIG. The width of the photosensitive drum is at least larger than the maximum size of paper that can be used in the image forming apparatus 10. The exposure devices of the transfer units 141Y, 141M, 141C, and 141K perform exposure scanning in the width direction of the photosensitive drum to form an electrostatic latent image. That is, the main scanning direction of the exposure apparatus is the width direction of the photosensitive drum, that is, the direction perpendicular to the paper surface of FIG.

  The intermediate transfer belt 142 conveys the toner image that has been primarily transferred by the transfer units 141Y, 141M, 141C, and 141K. On the intermediate transfer belt 142, yellow, magenta, cyan, and black toner images are superimposed and transferred so as to form a single image. The transfer roll 143 transfers (secondary transfer) the toner image conveyed by the intermediate transfer belt 142 to a sheet. The fixing device 144 heats the sheet on which the toner image is transferred by the transfer roll 143 and fixes the toner on the sheet. Each of the plurality of transport rollers 145 transports a sheet on which toner is fixed, and forms a sheet transport path.

  The path switching member 146 switches the paper transport path according to an image forming mode described later. The path switching member 146 is in either a position indicated by a solid line (hereinafter referred to as “first position”) or a position indicated by a broken line (hereinafter referred to as “second position”) during sheet conveyance. It is stationary. When the path switching member 146 is in the first position, the paper is conveyed to the first tray 147, while when the path switching member 146 is in the second position, the paper is conveyed to the second tray 148. .

  The first tray 147 and the second tray 148 accommodate sheets on which images are formed and conveyed by the conveyance roll 145. The first tray 147 accommodates paper on which a test image to be described later is formed, while the second tray 148 accommodates paper on which an image other than the test image is formed. An image reading unit 15 is attached to the first tray 147.

The image reading unit 15 reads an image formed on a sheet and generates image data representing the reading result.
FIG. 4 is a diagram illustrating a main configuration of the image reading unit 15. As shown in the figure, the image reading unit 15 includes a platen 151, a line sensor 152, a sensor moving mechanism 153, and a conveyor belt 154. Although not shown in the figure, the image reading unit 15 includes a signal processing circuit that converts an image signal that is an analog signal into image data that is digital data and outputs the image data.

The platen 151 is a transparent plate-like member and constitutes a part of the upper surface of the first tray 147. Note that the size of the platen 151 is approximately the same as or larger than the paper on which the image is formed.
The line sensor 152 is a line-shaped sensor provided along the sheet conveyance direction, and is formed by arranging a plurality of color light sources and imaging elements in a line shape below the platen 151. As the light source of the line sensor 152, for example, an LED (Light Emitting Diode) is used. Further, it is preferable to use three colors of red (red), green (green) and blue (blue) as the color of the light source. Here, the light sources of red, green, and blue are light sources that emit light having respective main wavelengths of around 620 nm (red), 525 nm (green), and 470 nm (blue). For example, a photodiode is used as the image sensor. Under such a configuration, the line sensor 152 irradiates light on the paper supported between the platen 151 and the conveyor belt 154, and the image sensor receives reflected light from the paper and according to the amount of light received. By generating an image signal, an image formed on the sheet is captured.

  The configuration of the image reading unit may be a combination of a white light source and a three-line color sensor in which a three-line configuration line sensor is covered with a color filter. That is, the image reading unit may use any type of light source or sensor as long as the image to be read can be split into three or more colors and read.

The sensor moving mechanism 153 includes a motor or the like, supports both ends of the line sensor 152, and moves it in a direction perpendicular to the paper surface of FIG. That is, the direction in which the line sensor 152 captures an image simultaneously is the main scanning direction of the line sensor 152, whereas the movement direction of the sensor moving mechanism 153 is the sub-scanning direction of the line sensor 152.
5 is a diagram showing the configuration of the platen 151, the line sensor 152, and the sensor moving mechanism 153 from the direction of the arrow A in FIG. In the figure, the platen 151 is indicated by a two-dot chain line. The sensor moving mechanism 153 reciprocates the line sensor 152 from the position indicated by the solid line in the drawing to the position indicated by the broken line. For example, the line sensor 152 has a width of about 210 mm and a movement distance of about 300 mm. With such a configuration, even when an A4 size (210 mm × 297 mm) sheet is conveyed in the longitudinal direction, the entire surface of the sheet can be read.

  The conveyor belt 154 is an endless belt member supported by the support rolls 154a and 154b. As the transport belt 154, a material whose surface has a frictional resistance capable of transporting paper is appropriately selected. The support rolls 154a and 154b are roll-shaped members that rotate, and are configured such that at least one of them is driven. The conveyance belt 154 conveys the sheet following the rotation of the support rolls 154a and 154b, and stops the sheet at an appropriate position.

The configuration of the image forming apparatus 10 is as described above. Next, the configuration of the control device 20 will be described with reference to the block diagram of FIG.
As shown in FIG. 6, the control device 20 includes a control unit 21, a storage unit 22, a communication unit 23, an operation unit 24, and a display unit 25. The control unit 21 includes a CPU, a ROM, a RAM, and the like, and controls the operation of each unit of the control device 20. The storage unit 22 is a storage device such as an HDD, and stores various data. The data stored in the storage unit 22 includes image data to be supplied to the image forming apparatus 10 and test image data.

The test image data is image data used to detect density unevenness in the main scanning direction that occurs in the image forming apparatus 10 and has a predetermined pattern.
FIG. 7 is a diagram illustrating an example of test image data. The test image data includes a plurality of belt-like images having the same gradation value in the main scanning direction of the image forming unit 14 (that is, the main scanning direction of the exposure apparatus), and each belt-like image has a predetermined floor. It is a key value. For example, the test image data D1 includes half-tone images of yellow (Y), magenta (M), cyan (C), and black (K) of 20%, 40%, 60%, 80%, and 100%, respectively. It was created to be formed on a sheet with a point percentage. The test image data D2 includes red (R), green (G), and blue (B) band images on the paper with halftone dot percentages of 20%, 40%, 60%, 80%, and 100%, respectively. It was created to be formed. Here, “percentage of halftone dots” indicates the coverage of toner per unit area, and 0% represents colorless (background color) and 100% represents a so-called solid color.
In the present embodiment, an image formed on a sheet using test image data is referred to as a “test image”.

Returning to the description of FIG. The communication unit 23 is an interface device for exchanging information via the network 40. The communication unit 23 supplies image data and an instruction regarding image formation to the image forming apparatus 10 via the network 40.
The operation unit 24 is an input device for a user of the control device 20 to input an instruction, and includes a keyboard and a mouse.
The display unit 25 is a display device such as a liquid crystal monitor, for example, and notifies the user of the control device 20 of various information.

  The client device 30 has substantially the same hardware configuration as that of the control device 20 described above, although there is a difference in data to be stored. The client device 30 outputs an instruction regarding image formation and image data in accordance with an instruction from the user. Instructions and image data relating to image formation are supplied to the image forming apparatus 10 via the control device 20.

[Operation of the embodiment]
With the above configuration, in the image forming system 100, the user instructs the client device 30 to cause the image forming device 10 to form an image. When instructing the image forming apparatus 10, the client apparatus 30 supplies image data that is a basis for image formation.
In the image forming system 100, an image is formed by two types of operation modes. One is a mode in which the user forms an image based on arbitrary image data, and this is hereinafter referred to as “normal mode”. The other is a mode for maintaining good image quality in the normal mode, and this is hereinafter referred to as “correction mode”.

The operation in the correction mode is performed when the user instructs this or at a predetermined timing. The timing for performing the operation in the correction mode includes, for example, a timing at which the image forming apparatus 10 is turned on, a timing at which a predetermined time has elapsed since the previous operation in the correction mode, and the like.
FIG. 8 is a sequence chart showing operations of the image forming apparatus 10 and the control apparatus 20 in the correction mode. Hereinafter, description will be given with reference to FIG.

  First, the control unit 21 of the control device 20 transmits an instruction to form a test image to the image forming device 10 (step S1). At this time, the control unit 21 transmits the test image data stored in the storage unit 22 to the image forming apparatus 10. In addition, by adding or embedding predetermined identification information to the test image data, this may be replaced with an instruction to form a test image. That is, the control unit 11 of the image forming apparatus 10 may determine whether or not the correction mode is set by determining whether or not the received image data includes identification information.

  When receiving the above instruction from the control device 20, the control unit 11 of the image forming apparatus 10 determines a mode to be executed (step S2). Here, since an instruction to form a test image is transmitted from the control device 20, the control unit 11 determines that the mode to be executed is the correction mode. Therefore, the control unit 11 thereafter controls each unit to perform an operation according to this mode.

  When it is determined that the mode to be executed is the correction mode, the control unit 11 moves the path switching member 146 to the first position so that the sheet is conveyed to the first tray 147 and the subsequent image. Prepare for formation (step S3). Then, the control unit 11 causes the image forming unit 14 to form the received image data, that is, a test image corresponding to the test image data (step S4). Specifically, the control unit 11 performs color space conversion on the test image data and supplies data for controlling the exposure amount of the laser beam of the exposure apparatus to each of the transfer units 141Y, 141M, 141C, and 141K. To form a test image.

  The sheet on which the test image is formed is conveyed to the first tray 147 because the path switching member 146 is at the first position. When transported to the first tray 147, the control unit 11 transports the paper onto the transport belt 154 of the image reading unit 15 and stops it at an appropriate position (step S5). At this time, the control unit 11 conveys the sheet to a position where the position where the sheet should be read is located on the platen 151.

  Thereafter, the control unit 11 causes the line sensor 152 and the sensor moving mechanism 153 to perform an operation for capturing a test image formed on the sheet (step S6). The control unit 11 reads the image data while moving the line sensor 152 to the sensor moving mechanism 153 and stores it in the RAM. And the control part 11 transmits this image data to the control apparatus 20 (step S7).

  When receiving the image data representing the test image, the control unit 21 of the control device 20 generates correction information based on the received image data (step S8). The correction information is information for correcting density unevenness in the main scanning direction of the image forming unit 14 and is information corresponding to the above-described lookup table. Specifically, the control unit 21 compares the pixel data constituting the image data representing the test image with respect to each line in the sub-scanning direction (direction corresponding to the main scanning direction of the image forming unit 14). Judge the variation.

  Since the test image is a set of the band-like images described above, it should originally have a constant density in the sub-scanning direction. However, when the image forming unit 14 causes density unevenness in the main scanning direction, the density varies. That is, the fact that the gradation value of the image data representing the test image has variations in the sub-scanning direction indicates density unevenness in the main scanning direction of the image forming unit 14. Therefore, the control unit 21 generates correction information so that the look-up table acts in a direction to suppress density unevenness in the main scanning direction of the image forming unit 14. For example, when the density unevenness is such that the central portion in the main scanning direction is thinner than the end portion, the control unit 21 looks that an image in which the central portion has a relatively high density is formed. The up table is calculated.

  When the correction information, that is, the lookup table is generated, the control unit 21 transmits it to the image forming apparatus 10 (step S9). When receiving the lookup table, the control unit 11 of the image forming apparatus 10 stores it in the storage unit 12 (step S10). As a result, the operation in the correction mode is completed, and the image forming apparatus 10 is in a state where the operation in the normal mode can be executed. The image forming apparatus 10 uses the look-up table stored in step S10 for subsequent image formation.

  When the image forming apparatus 10 and the control apparatus 20 perform the operation as described above, the image forming apparatus 10 updates the look-up table every time the operation in the correction mode is executed. The image forming apparatus 10 is configured so that the main scanning direction of the image reading unit 15 that reads a test image is orthogonal to the paper conveyance direction, and therefore, the image reading unit 15 determines the image reading unit 15 for each image sensor of the image reading unit 15. It is possible to prevent the noise caused by the variation of. Therefore, according to the image forming system 100 of the present embodiment, density unevenness caused by the image forming unit 14 can be detected with higher accuracy, and more appropriate correction can be performed. Further, according to the image forming system 100 of the present embodiment, a test image can be read without human intervention, and the convenience of correction can be improved.

[Modification]
Although the present invention has been described with reference to one preferred embodiment, the present invention is not limited to the above-described embodiment, and various modifications can be made. An example is shown below.

  In the embodiment described above, the control device 20 that generates the correction information is provided. However, the image forming apparatus 10 may have a function corresponding to the control device 20 described above. That is, the configuration corresponding to the above-described embodiment can be realized by a single image forming apparatus.

  In the above-described embodiment, the correction information corresponds to the lookup table applied to the image data. However, the aspect of the correction information is not limited to this. In short, the correction information may be in any form as long as it can eliminate unevenness in the main scanning direction of the exposure apparatus.

  In the above-described embodiment, the image reading unit 15 stops the conveyance of the paper when reading the paper on which the test image is formed. However, the configuration may be such that the conveyance of the paper is not stopped. For example, the conveyance speed when reading the paper on which the test image is formed may be lowered than before, or the reading may be performed while the conveyance speed is constant.

When reading is performed without stopping the conveyance of the sheet, the image data represents an image having a shape different from that of the actual image. For example, a rectangular strip image is distorted into a parallelogram. If it does so, the image pick-up element which reads the same strip | belt-shaped image will not become the same, and there exists a possibility of receiving the influence of the dispersion | variation for every image pick-up element.
Therefore, when reading without stopping the conveyance of the sheet, it is preferable to use test image data as shown in FIG. The test image data shown in FIG. 9 has a configuration in which the belt-like image is tilted in advance in consideration of the relative change of the imaging position as the paper is conveyed. For example, if the sheet conveyance speed and the movement speed of the line sensor 152 are predetermined speeds, and v ₁ (paper conveyance speed) and v ₂ (line sensor 152 movement speed), respectively, If L _a and L _b satisfy the following expression (1), it is theoretically possible to always read the same density region with the same image sensor.

1 is a diagram illustrating an overall configuration of an image forming system according to an embodiment of the present invention. 1 is a block diagram illustrating a configuration of an image forming apparatus. FIG. 2 is a diagram illustrating main configurations of an image forming unit and an image reading unit of the image forming apparatus. FIG. 3 is a diagram illustrating a main configuration of an image reading unit of the image forming apparatus. FIG. 3 is a diagram illustrating a main configuration of an image reading unit of the image forming apparatus. 3 is a block diagram showing a configuration of a control device 20. FIG. It is a figure which shows an example of test image data. 6 is a sequence chart showing operations of the image forming apparatus and the control apparatus. It is a figure which shows an example of test image data.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Image forming system, 10 ... Image forming apparatus, 11 ... Control part, 12 ... Memory | storage part, 13 ... Communication part, 14 ... Image forming part, 141Y, 141M, 141C, 141K ... Transfer unit, 142 ... Intermediate transfer belt, 143: Transfer roll, 144: Fixing unit, 145 ... Conveyance roll, 146 ... Path switching member, 147 ... First tray, 148 ... Second tray, 15 ... Image reading unit, 151 ... Platen, 152 ... Line sensor, 153 ... Sensor moving mechanism, 154 ... conveyor belt, 20 ... control device, 21 ... control unit, 22 ... storage unit, 23 ... communication unit, 24 ... operation unit, 25 ... display unit, 30 ... client device, 40 ... network

Claims (5)

Image forming means for continuously forming an image having a predetermined width in the first direction of the sheet-like material on the sheet-like material based on the supplied image data;
Conveying means for conveying the sheet-like material on which an image is formed by the image forming means, along a second direction orthogonal to the first direction;
An image pickup means provided with a plurality of image pickup elements for generating an image signal obtained by picking up an image formed on the sheet-like object being conveyed or conveyed by the conveyance means, along the second direction of the sheet-like object; ,
An image forming apparatus comprising: a moving unit that moves the imaging unit in a direction orthogonal to the second direction. The conveying means is
2. The image forming apparatus according to claim 1, wherein when the imaging unit captures an image, the conveyance speed of the sheet-like material is reduced or the conveyance of the sheet-like material is stopped. The conveying means is
The transport path of the sheet-like object on which the image is formed by the image forming unit is selected from the first transport path that guides the sheet-like object to the imaging unit and the second transport path that is different from the first transport path. The image forming apparatus according to claim 1, further comprising a path switching unit that determines whether or not. Supply means for supplying image data to the image forming means;
Extracting means for extracting information about unevenness in the first direction of the image formed on the sheet-like material by the image forming means;
Correction means for correcting the image data supplied by the supply means to the image forming means in the first direction based on the information extracted by the extraction means;
The supply means includes
Supplying image data representing a test image for detecting unevenness in the first direction of the image;
The imaging means includes
Generating an image signal representing the test image while being moved by the moving means;
The extraction means includes
The image forming apparatus according to claim 1, wherein the information is extracted based on an image signal representing the test image generated by the imaging unit. An image forming system comprising an image forming apparatus and a control device that controls the image forming apparatus,
The image forming apparatus includes:
Image forming means for continuously forming an image having a predetermined width in the first direction of the sheet-like material on the sheet-like material based on the image data;
Conveying means for conveying the sheet-like material on which an image is formed by the image forming means in a second direction orthogonal to the first direction;
An image pickup means provided with a plurality of image pickup elements for generating an image signal obtained by picking up an image formed on the sheet-like object being conveyed or conveyed by the conveyance means, along the second direction of the sheet-like object; ,
Moving means for moving the imaging means in a direction orthogonal to the second direction;
A supply unit that supplies image data representing a test image for detecting unevenness in the first direction of the image to the image forming unit;
The controller is
Obtaining means for obtaining an image signal generated by the imaging means based on a test image formed by the image forming means based on test image data supplied by the supplying means;
An image forming system, comprising: an extracting unit that extracts information about unevenness in the first direction based on an image signal representing the test image acquired by the acquiring unit.

Images