JP2022028178A - Image formation apparatus, and method for determining presence or absence of abnormality in image reading section - Google Patents

Abstract

To enable detection of abnormality in an image reading section without troubling a user and without increasing cost of an apparatus.SOLUTION: A control section in an image formation apparatus 1 according to the present invention compares a reading result of a first image by a first image reading section 30 with a reading result of the first image by a second image reading section 60, thereby performing processing for determining presence or absence of abnormality in the first image reading section 30 or the second image reading section 60.SELECTED DRAWING: Figure 1

Description

The present invention relates to an image forming apparatus and a method for determining the presence or absence of an abnormality in an image reading unit.

Conventionally, in an image forming apparatus such as an inkjet printer or an LED (Light Emitting Diode) printer, a vertical streak (a streak along a sub-scanning direction) is formed on a printed matter by analyzing a read image obtained by reading the printed matter with a line sensor or the like. It is inspected whether or not a defect such as the above has occurred. Streaks in printed matter occur when an abnormality (such as ejection failure of the nozzle of an inkjet printer) occurs in the image forming part, but dust, etc. on the reading surface of the line sensor that reads the printed matter and the white correction plate used for shading correction. It also occurs when foreign matter is attached or when the cell in the line sensor has a problem. That is, it also occurs when an abnormality has occurred in the image reading unit.

Then, when it is erroneously determined that there is an abnormality in the image forming portion even though foreign matter such as dust is attached to the reading surface of the line sensor that reads the printed matter and the white correction plate used for shading correction, the image is imaged. Corrections are made to eliminate vertical streaks caused by abnormalities in the formed portion. For example, in the correction of ejection defects of the nozzles of an inkjet printer, corrections are made to increase the amount of ink ejected from nozzles in the vicinity of the nozzles determined to have ejection defects. That is, overcorrection is performed by increasing the amount of ink ejected to a portion where the nozzle ejection failure does not occur. As a result, vertical streaks along the sub-scanning direction appear at that location. Therefore, it is necessary to appropriately determine whether or not an abnormality has occurred in the image reading unit, including the adhesion of foreign matter to the reading surface of the line sensor and the white correction plate, and the malfunction of the cell in the line sensor.

For example, in Patent Document 1, a reading unit that transfers optical information indicating an image of a manuscript form and the transferred optical information are used to convert an image into a first pixel signal that constitutes a pixel at a first resolution. A first sensor, a second sensor that uses the transferred optical information to convert an image into a second pixel signal that constitutes a pixel at a second resolution higher than the first resolution, and a first and first sensor. Using the resolution conversion unit that converts one of the two pixel signals to the same resolution as the other pixel signal, and the first and second pixel signals converted to the same resolution, the corresponding pixel is used. The foreign matter presence / absence determination unit that detects whether or not there is a foreign matter, and at least for the pixels that are determined to have foreign matter, the foreign matter is generated by using the first and second pixel signals corresponding to the pixels located in the vicinity thereof. According to the signal sorting unit that detects whether the abnormality is occurring in the first or second pixel signal of the pixel determined to be present, and the detection results obtained by the foreign matter presence / absence determining unit and the signal sorting unit. , The image quality deterioration correction unit that corrects the first or second pixel signal, and the manuscript form are classified into arbitrary patterns, and the correction judgment that determines whether or not the image quality deterioration correction unit performs correction according to this pattern result. Department and
An image reader comprising the above is disclosed.

According to the technique described in Patent Document 1, it is possible to detect streaks due to foreign matter on the reading optical path, and further, when image quality deterioration occurs due to foreign matter on the document, the place where the streaks occur is the background, the character portion, or the character portion. It is possible to detect on which pattern the image is generated, such as in the photo section.

Further, Patent Document 2 is an image forming apparatus including a scanner for reading an image and a print head for printing, and is read by a head control means for controlling the print head to print a test pattern and a scanner. An image forming apparatus including an image processing means for diagnosing a defect of a print head and a scanner by determining and processing image data of a test pattern is described. In the image forming apparatus described in Patent Document 2, the head control means prints the test pattern multiple times, or the scanner reads the test pattern multiple times, so that the correct answer of the determination result of the nozzle defect or the optical system defect is correct. The rate can be improved.

Japanese Unexamined Patent Publication No. 2010-246125 Japanese Unexamined Patent Publication No. 2001-007969

However, in the technique described in Patent Document 1, since it is necessary to use a plurality of sensors having different resolutions, the processing becomes complicated and the cost of the image forming apparatus increases. Further, in the technique described in Patent Document 2, in order to improve the accuracy of determination of a nozzle defect and an optical system defect, it is necessary to print and read the test pattern a plurality of times, which is troublesome for the user.

The present invention has been made in view of such a situation, and an object of the present invention is to be able to detect an abnormality in an image reading unit without bothering the user and increasing the cost of the device. To be.

In order to solve the above problems, the image forming apparatus on one side of the present invention has a first image forming unit that forms a first image on a first surface, which is one surface of a recording material, and a first image forming unit. A first image reading unit that reads a first image formed by the unit, a second image forming unit that forms a second image on a second surface that is different from the first surface of the recording material, and a second image forming unit. A second image reading unit for reading a first image or a second image, and a control unit are provided. The control unit compares the reading result of the first image by the first image reading unit with the reading result of the first image by the second image reading unit, whereby the first image reading unit or the second image reading unit or the second image reading unit is used. Performs abnormality determination processing in the image reading unit of.

Further, in the method for determining the presence or absence of abnormality in the image reading unit on one side of the present invention, a first image forming unit that forms a first image on a first surface, which is one surface of a recording material, and a first image forming unit. A first image reading unit that reads a first image formed by the unit, a second image forming unit that forms a second image on a second surface that is different from the first surface of the recording material, and a second image forming unit. This is a method for determining the occurrence of an abnormality in an image reading unit by an image forming apparatus including a second image reading unit for reading a first image or a second image and a control unit. Then, in the method of determining the presence or absence of abnormality in the image reading unit on one aspect of the present invention, the control unit controls the reading result of the first image by the first image reading unit and the first image by the second image reading unit. It has a procedure for performing abnormality presence / absence determination processing in the first image reading unit or the second image reading unit by comparing with the reading result.

According to the present invention, the first image reading unit or the second image reading unit or the second image reading unit is compared with the reading result of the first image by the first image reading unit and the reading result of the first image by the second image reading unit. It is determined whether or not there is an abnormality in the image reading unit of. Therefore, according to the present invention, it is possible to detect an abnormality in the image reading unit without bothering the user and increasing the cost of the device. Issues, configurations and effects other than those described above will be clarified by the following description of the embodiments.

It is a schematic diagram which shows the whole structure of the image formation system which concerns on one Embodiment of this invention. It is a schematic block diagram which shows the whole structure of the image forming part of the 1st image forming apparatus which concerns on one Embodiment of this invention. It is a top view which shows the head unit in the state seen from the paper side which concerns on one Embodiment of this invention. It is a perspective view which shows the structural example of the 1st image reading apparatus and a white correction plate which concerns on one Embodiment of this invention. It is a block diagram which shows the structural example of the control system of the 1st image forming apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows the structural example of the control system of the 1st image reading apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows the structural example of the control system of the 1st printer controller which concerns on one Embodiment of this invention. It is a block diagram which shows the structural example of the control system of the 1st control apparatus which concerns on one Embodiment of this invention. A head in the case where no deposit is attached to the image reading surface or white correction plate of the first image reading device and the image reading surface or white correction plate of the second image reading device according to the embodiment of the present invention. It is a figure which shows the structural example of the reading image of an image. It is a figure which shows the structural example of the reading image of the head image in the case where the deposit is attached to the image reading surface or the white correction plate of the 1st image reading apparatus which concerns on one Embodiment of this invention. It is a figure which shows the structural example of the reading image of the head image in the case where the deposit is attached to the image reading surface or the white correction plate of the 2nd image reading apparatus which concerns on one Embodiment of this invention. It is a figure which shows the example of the reading image of the head image for confirmation of the nozzle ejection failure based on the surface adjustment data shown in FIG. 9 or FIG. 10 which concerns on one Embodiment of this invention. It is a flowchart which shows the example of the procedure of the image quality adjustment method in a normal time by the image formation system which concerns on one Embodiment of this invention. It is a flowchart which shows the example of the image formation processing by the image formation system after performing the image quality adjustment which concerns on one Embodiment of this invention. It is a flowchart which shows the example of the procedure of the image quality adjustment method when the abnormality occurs in the image reading apparatus by the conventional image formation system. It is a flowchart which shows the example of the image formation processing by the image formation system after the image quality adjustment is performed which concerns on one Embodiment of this invention. It is a flowchart which shows the example of the procedure of the image quality adjustment method by the image formation system which concerns on one Embodiment of this invention. It is a flowchart which shows the example of the abnormality presence | absence determination processing of the image reading apparatus by the 1st control apparatus which concerns on one Embodiment of this invention.

Hereinafter, examples of embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same function or configuration are designated by the same reference numerals, and duplicate description of the components will be omitted.

<Structure of image formation system>
First, the overall configuration of the image forming system according to the embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic view showing an overall configuration of an image forming system 1 (an example of an image forming apparatus). It should be noted that FIG. 1 describes the elements required for the explanation of the present invention or related elements thereof, and the image forming system of the present invention is not limited to the example shown in FIG.

As shown in FIG. 1, the image forming system 1 includes a paper feeding device 10, a first image forming device 20, a first image reading device 30 (an example of a first image reading unit), a paper reversing unit 40, and a first image forming device. 2. The image forming device 50, the second image reading device 60 (an example of the second image reading unit), and the paper ejection device 70 are included. Further, the image forming system 1 includes a first printer controller 101, a first control device 102 (an example of a control unit), a second printer controller 103, and a second control device 104. Each of these devices constituting the image forming system 1 is communicably connected via a network N including a LAN (Local Area Network) or the like.

The paper feed device 10 has a plurality of paper feed trays in which paper of various paper types and paper sizes (an example of recording material) is stored, and the paper stored in the paper feed tray is used as the first image forming apparatus 20. Paper is fed to the paper transport unit 210 (see FIG. 5).

The first image forming apparatus 20 is an image forming apparatus that forms an image on paper by an inkjet method, and is a surface of paper (an example of the first surface) based on a print job input from the first printer controller 101. An image is formed (printed) on the paper. When the surface adjustment chart data is transmitted from the first printer controller 101, the first image forming apparatus 20 forms a surface adjustment chart (an example of the first image) on the surface of the paper.

The first printer controller 101 performs RIP (Raster Image Processor) processing on drawing data included in a print job transmitted from a terminal device (not shown) to generate image data such as surface adjustment chart data. do. Then, the first printer controller 101 transmits the generated image data to the first image forming apparatus 20.

Further, the first printer controller 101 controls the first image forming apparatus 20 to perform image quality adjustment processing based on the surface adjustment data when the surface adjustment data is transmitted from the first control device 102. conduct. The image quality adjustment process is a process of reflecting the surface adjustment data in the image formation by the first image forming apparatus 20 from the next time onward.

The first image reading device 30 includes an in-line sensor 330 (see FIG. 6), and covers the entire surface of one page of a paper on which an image such as a surface adjustment chart output from the first image forming device 20 is formed. read. The first image reading device 30 transmits the read image read by the inline sensor 330 to the first control device 102.

Further, the first image reading device 30 has a white correction plate 332 (see FIG. 4) at the position of the image reading surface 331 (see FIG. 4) of the inline sensor 330 when reading the surface adjustment chart (when performing image quality adjustment). 4) is moved to perform shading correction for image quality adjustment. The configuration of the in-line sensor 330 and the white correction plate 332 will be described in detail with reference to FIG. 4 described later.

The first control device 102 is a control device that controls the operation of the first image reading device 30. When the scanned image transmitted from the first image reading device 30 is a scanned image of the surface adjustment chart, the first control device 102 determines the surface adjustment data (first surface) based on the scanned image. (Example of adjustment data) is generated. Specifically, the first control device 102 decomposes an image for each color of the read image and for each image formed by each recording head 242 (see FIG. 3) of the first image forming device 20. Then, the first control device 102 generates surface adjustment data based on the information obtained from each decomposed image, and transmits the surface adjustment data to the first printer controller 101.

Further, when the surface adjustment data is created, the first control device 102 determines whether or not a ejection defect has occurred in the nozzle of the recording head 242 of the head unit 24 of the first image forming device 20 based on the read image. Is determined. That is, the first control device 102 determines that a ejection defect has occurred in the head when the ink ejection from the nozzle to which the ink should be originally output cannot be confirmed. Then, surface adjustment data for compensating for this ejection defect is generated. Complementing the ejection defect of the head can be performed, for example, by increasing the amount of ink ejected from the nozzle adjacent to the nozzle in which the ejection defect has occurred.

Further, when the first control device 102 receives the surface adjustment data from the second control device 104, the surface adjustment data created by the own device and the surface adjustment data are transmitted from the second control device 104. Compare with surface adjustment data. The surface adjustment data transmitted from the second control device 104 is based on the scanned image obtained by reading the surface adjustment chart printed by the first image forming apparatus 20 by the second image reading device 60. It is the adjustment data for the surface generated by the second control device 104. That is, the first control device 102 compares the surface adjustment data generated by each of the first control device 102 and the second control device 104 based on the read image of the same surface adjustment chart.

Then, the first control device 102 determines whether or not the cause of dirt, vertical streaks, or the like is due to an abnormality in the first image reading device 30 or the second image reading device 60. The abnormality of the first image reading device 30 or the second image reading device 60 includes the adhesion of foreign matter such as dust to the image reading surface 331 of the inline sensor 330 or the white correction plate 332 (see FIG. 4). Among the cells included in the in-line sensor 330, there is a failure of a specific cell. The details of the abnormality presence / absence determination processing of the image reading device by the first control device 102 will be described in detail with reference to FIG. 18 described later.

When the paper reversing unit 40 is instructed to perform double-sided printing in the print job, the paper reversing unit 40 inverts the surface of the paper output from the first image forming apparatus 20 to form a second image. Transport to device 50. On the other hand, when single-sided printing is instructed in the print job, the surface of the paper output from the first image forming apparatus 20 is conveyed to the second image forming apparatus 50 without being inverted. Further, the paper reversing unit 40 does not invert the surface of the paper output from the first image forming apparatus 20 even when the image reading device abnormality presence / absence determination process is performed by the first control device 102, and the second sheet reversing unit 40 does not invert the surface of the paper. It is conveyed to the image forming apparatus 50. The mechanism and configuration of the paper reversing unit 40 may be any mechanism and configuration as long as the front and back surfaces of the paper can be inverted.

The second image forming apparatus 50 is an image forming apparatus that forms an image on paper by an inkjet method, and is the back surface of the paper (an example of the second surface) based on a print job input from the second printer controller 103. Form an image. When the back side adjustment chart data is transmitted from the second printer controller 103, the second image forming apparatus 50 forms the back side adjustment chart (an example of the second image) on the back side of the paper.

The second image forming apparatus 50 does not print the image on the conveyed paper when the image reading device abnormality presence / absence determination processing is performed by the first control device 102, and the second image forming apparatus 50 does not print the image on the conveyed paper as it is. Transport to the image reader 60.

The second printer controller 103 performs RIP processing on the drawing data included in the print job transmitted from the terminal device (not shown) to generate image data such as backside adjustment chart data. Then, the second printer controller 103 transmits the generated image data to the second image forming apparatus 50. Further, when the back surface adjustment data is transmitted from the second control device 104, the second printer controller 103 causes the second image forming apparatus 50 to reflect the front surface adjustment data in the next and subsequent image formation. Perform image quality adjustment processing.

The second printer controller 103 does not generate backside adjustment chart data when the image reading device abnormality presence / absence determination process is performed by the first control device 102.

The second image reading device 60 includes an in-line sensor (not shown) and reads the entire surface of one page of the paper on which the image such as the adjustment chart for the back surface is formed, which is output from the second image forming device 50. The second image reading device 60 transmits the read image read by the inline sensor to the second control device 104. Further, the second image reading device 60 uses the reading image obtained by reading the surface adjustment chart by the in-line sensor as the second control device when the image reading device abnormality presence / absence determination process is performed by the first control device 102. Send to 104.

The second control device 104 is a control device that controls the operation of the second image reading device 60. When the scanned image transmitted from the second image reading device 60 is a scanned image of the back surface adjustment chart, the second control device 104 generates back surface adjustment data based on the scanned image. Specifically, the second control device 104 decomposes an image for each color of the read image and for each image formed by each recording head (not shown) of the second image forming device 50. Then, the second control device 104 generates backside adjustment data based on the information obtained from each decomposed image, and transmits the backside adjustment data to the second printer controller 103.

Further, the second control device 104 is based on the image read from the surface adjustment chart transmitted from the second image reading device 60 when the image reading device abnormality presence / absence determination process is performed by the first control device 102. Generate surface adjustment data. Then, the second control device 104 transmits the surface adjustment data to the first control device 102.

The paper ejection device 70 includes a paper ejection tray 71 and a purge tray 72. Paper on which an image is normally formed is ejected to the output tray 71. Paper on which the front / back adjustment chart is printed and paper on which an image is not normally formed are discharged to the purge tray 72.

<Structure of image forming unit of image forming apparatus>
Next, with reference to FIG. 2, a configuration example of the image forming unit 240 (an example of the first image forming unit: see FIG. 5) of the first image forming apparatus 20 according to the present embodiment will be described. FIG. 2 is a schematic configuration diagram showing the overall configuration of the image forming unit 240 of the first image forming apparatus 20. Since the configuration of the image forming unit of the second image forming apparatus 50 is also the same as the configuration shown in FIG. 2, only the overall configuration of the image forming apparatus 240 will be described here, and the second image forming apparatus 50 will be described. The description of the configuration of the image forming unit will be omitted.

The image forming unit 240 of the first image forming apparatus 20 shown in FIG. 2 ejects (injects) ink droplets from a plurality of nozzles provided in the recording head 242 (see FIG. 3) of the head unit 24. Form an image on paper. The image forming unit 240 forms an image on paper by superimposing, for example, four colors of inks of yellow (Y), magenta (M), cyan (C), and black (K). The type of color used by the image forming unit 240 is not limited to the four types of Y, M, C, and K, and other colors may be used.

As shown in FIG. 2, the image forming unit 240 includes a paper supply unit 12, an image forming drum 21, a delivery unit 22, a heating unit 23, four head units 24, a fixing unit 25, a paper ejection unit 26, and the like.

The paper supply unit 12 supplies the paper fed from the paper feed device 10 to the image forming drum 21. The image forming drum 21 is formed in a cylindrical shape and is rotationally driven by a drive motor (not shown) to rotate counterclockwise (direction indicated by a semicircular arrow in the figure). Paper supplied from the paper feeding device 10 (see FIG. 1) is supported on the outer peripheral surface of the image forming drum 21. Then, the image forming drum 21 conveys the paper by rotating while supporting the paper. The heating unit 23, the head unit 24, and the fixing unit 25 are arranged so as to face the outer peripheral surface of the image forming drum 21, respectively.

The delivery unit 22 is provided between the paper supply unit 12 and the image forming drum 21. The delivery unit 22 includes a claw portion 221 and a cylindrical delivery drum 222 and the like. The claw portion 221 supports one end of the paper conveyed by the paper supply portion 12. The transfer drum 222 guides the paper supported on the claw portion 221 toward the image forming drum 21. As a result, the paper is delivered from the paper supply unit 12 to the outer peripheral surface of the image forming drum 21 via the delivery unit 22.

A heating unit 23 is arranged on the downstream side of the delivery drum 222 in the paper transport direction. The heating unit 23 has, for example, a heating wire, and generates heat when energized. Under the control of the control unit 200 (see FIG. 5), the heating unit 23 heats the paper supported on the image forming drum 21 so that the paper passing in the vicinity of the heating unit 23 reaches a predetermined temperature.

A head unit 24 is provided on the downstream side of the heating unit 23 in the paper transport direction. Four head units 24 are provided corresponding to each color of yellow, magenta, cyan, and black. The four head units 24 are arranged in the order of yellow, magenta, cyan, and black from the upstream side with respect to the paper transport direction.

The head unit 24 is a recording unit that ejects ink droplets from each of a plurality of nozzles of the plurality of recording heads 242 (see FIG. 3) to form an image on paper. The length of the head unit 24 is set to a length (page width) that covers the entire paper in a direction orthogonal to the paper transport direction (paper width direction). That is, the first image forming apparatus 20 (and the second image forming apparatus 50) according to the present embodiment is a single-pass type line head type inkjet that forms an image by causing the head unit 24 to scan the paper only once. It is a recording device. The four head units 24 have the same configuration as each other except that the color of the ink to be ejected is different from each other. Details of the head unit 24 will be described later with reference to FIG.

The fixing portion 25 is arranged on the downstream side of the four head units 24 in the paper transport direction. As the fixing portion 25, for example, a fluorescent tube or the like that irradiates ultraviolet rays such as a low-pressure mercury lamp is applied. Then, the fixing portion 25 irradiates the paper conveyed by the image forming drum 21 with ultraviolet rays to cure the ink droplets ejected on the paper. As a result, the fixing unit 25 fixes the image formed on the paper.

The paper ejection unit 26 includes a cylindrical separation drum 261 and an ejection belt 262 and the like. The separation drum 261 separates the paper supported on the image forming drum 21 from the outer peripheral surface of the image forming drum 21. Then, the separation drum 261 guides the paper to the discharge belt 262.

The discharge belt 262 is formed in an endless shape and is rotatably supported by a plurality of rollers (not shown). The discharge belt 262 feeds the paper delivered by the separation drum 261 to the first image reading device 30 in the subsequent stage. In the case of the discharge belt 262 in the second image forming apparatus 50, the discharge belt 262 is sent out to the second image reading device 60.

[Head unit configuration example]
Next, a configuration example of the head unit 24 of the first image forming apparatus 20 will be described with reference to FIG. FIG. 3 is a plan view showing the head unit 24 when viewed from the paper side. Since the configuration of the head unit of the second image forming apparatus 50 is also the same as the configuration shown in FIG. 3, only the configuration of the head unit 24 of the first image forming apparatus 20 will be described here, and the second image The description of the configuration of the head unit of the forming apparatus 50 will be omitted.

The head unit 24 includes a plurality of recording heads 242a to 242f. In the following description, when it is not necessary to individually distinguish the recording heads 242a to 242f, these are collectively referred to as the recording head 242.

FIG. 3 schematically shows the position of the nozzle of the recording head 242. The nozzles are arranged in a direction intersecting the paper transport direction (paper transport direction: the direction indicated by the downward arrow in the drawing) (in the present embodiment, the main scanning direction: the direction indicated by the right arrow in the drawing). .. This nozzle arrangement direction is called the nozzle row direction. The six recording heads 242a to 242f are arranged in a staggered manner so that the arrangement ranges in the nozzle row direction partially overlap each other. The nozzles of the recording heads 242a, 242c, and 242e arranged in odd numbers along the nozzle row direction are located on the same straight line in the nozzle row direction, and the recording heads 242b, 242d, and 242f arranged in even numbers. The nozzles are located on the same line in the nozzle row direction.

Further, the six recording heads 242a to 242f are nozzles in the vicinity of one end of one recording head 242 among a plurality of nozzles (nozzles) provided in each of the pair of recording heads 242 adjacent to each other. And the nozzle in the vicinity of the other end of the other recording head 242 and the nozzle in the nozzle row direction overlap each other, and the recording heads 242 are arranged so as to be offset from each other in the nozzle row direction.

In other words, the six recording heads 242a to 242f include a range in which the arrangement ranges of the nozzle groups provided in each in the nozzle row direction are different from each other, and the ranges in which ink can be ejected are continuously connected in the nozzle row direction. They are arranged in a good positional relationship. An overlapping range R (joint) is set in each range in the nozzle row direction in which the nozzle groups of the recording heads 242a to 242f are arranged so as to overlap each other. In each overlapping range R, ink is complementarily ejected from each nozzle of the pair of recording heads 242 in which the nozzles are provided in the overlapping range R. In the present embodiment, the entire range in the nozzle row direction in which the nozzle groups of the pair of recording heads 242 are arranged overlapping each other is defined as the overlapping range R.

The number and arrangement of the recording heads 242 are not limited to the above-mentioned example, and may be configured such that five or less or seven or more recording heads 242 are arranged.

Further, the recording head 242 is an inkjet head having a plurality of recording elements including a nozzle for ejecting ink droplets toward the paper. In addition to the nozzle, the recording element includes a pressure chamber for storing ink and a piezoelectric element (not shown) provided on the side wall of the pressure chamber, and the nozzle communicates with the pressure chamber. A drive voltage for deforming the piezoelectric element is supplied to the recording head 242 from the head drive unit 241 (see FIG. 5) as a drive condition according to the pixel value of the image data.

Then, due to the deformation operation of the piezoelectric element, the pressure chamber is deformed according to the drive voltage from the head drive unit 241 to change the pressure in the pressure chamber, and ink droplets are ejected from the nozzle communicating with the pressure chamber. The operation is performed. As a result, in each of the recording heads 242, ink droplets having a liquid amount corresponding to the pixel value of the image data are ejected from the plurality of nozzles toward the paper, and an image is formed on the paper supported by the image forming drum 21. Will be done.

<Structure of image reader and white correction plate>
Next, with reference to FIG. 4, the configuration of the in-line sensor 330 and the white correction plate of the first image reading device 30 will be described. FIG. 4 is a perspective view showing a configuration example of the inline sensor 330 and the white correction plate 332. Since the configuration of the inline sensor of the second image reading device 60 is also the same as the configuration shown in FIG. 4, only the configuration of the inline sensor of the first image reading device 30 will be described, and the second image reading device 60 will be described. The description of the configuration of the in-line sensor is omitted.

FIG. 4A shows the configuration of the inline sensor 330 in a state where the image reading surface 331 of the inline sensor 330 is arranged on the upper side in the Z direction. In the figure, "X" indicates the paper width direction (main scanning direction), "Y" indicates the paper conveying direction (secondary scanning direction), and "Z" indicates the vertical direction. The surface of the image reading surface 331 of the inline sensor 330 is covered with glass, and a line camera made of CCD (Charge Coupled Device Image Sensor) or CMOS (Complementary Metal Oxide Semiconductor Image Sensor) or the like is formed on the lower side of the glass in the Z direction. (In-line sensor) is provided.

The length of the image reading surface 331 in the X direction is set longer than the maximum width assumed as the paper width. As a result, the in-line sensor 330 can read the information in the main scanning direction of the paper at once without scanning in the main scanning direction.

FIG. 4B shows the configuration of the in-line sensor 330 in a state where the image reading surface 331 is arranged on the lower side in the Z direction. The in-line sensor 330 is arranged in the image forming system 1 in the posture shown in FIG. 4B, and reads the paper transported on the transport surface Sf shown by the broken line. The white correction plate 332 is a plate used for determining the white level and the black level at the time of shading correction, and the surface of the white correction plate 332 facing the image reading surface 331 is covered with glass.

The white correction plate 332 is normally retracted to a standby position (position of "(P1)" shown in the figure) in the image reading surface 331 where the inline sensor cannot read, but when shading correction is executed, the white correction plate 332 is normally retracted. It moves to the position directly below the image reading surface 331 in the Z direction (the position of "(P2)" indicated by the alternate long and short dash line in the figure). Then, the shading correction of the inline sensor 330 is performed by the first control device 102 based on the white level and the black level calculated by reading the white correction plate 332 by the inline sensor 330.

At this time, if the surface of the white correction plate 332 has deposits such as dust, the white level in the pixel corresponding to the spot is lower than that in the other pixels, so that it corresponds to the deposit in the scanned image. At the position, vertical streaks are generated along the sub-scanning direction.

The shading correction using the white correction plate 332 is performed before the surface adjustment chart is read by the inline sensor 330. However, it is not performed when the execution interval from the previous execution of the surface adjustment chart reading is short, or when the temperature of the in-line sensor 330 measured by a thermometer (not shown) does not change in the time direction. Sometimes.

<Structure of the control system of the first image forming apparatus>
Next, the configuration of the control system of the first image forming apparatus 20 will be described with reference to FIG. FIG. 5 is a block diagram showing a configuration example of the control system of the first image forming apparatus 20. Since the configuration of the control system of the second image forming apparatus 50 is the same as the configuration of the control system of the first image forming apparatus 20, only the configuration of the control system of the first image forming apparatus 20 will be described here. However, the description of the configuration of the control system of the second image forming apparatus 50 will be omitted.

As shown in FIG. 5, the first image forming apparatus 20 includes a control unit 200. The control unit 200 is, for example, a ROM (Read Only Memory) for storing a CPU (Central Processing Unit) 201, a RAM (Random Access Memory) 202 used as a work area of the CPU 201, a program executed by the CPU 201, and the like. Includes 203 and the like.

The CPU 201 of the control unit 200 is connected to each unit constituting the first image forming apparatus 20 via the system bus B1 and controls the operation of each unit.

Further, the control unit 200 includes a storage unit 204 as a large-capacity storage device including an HDD (Hard Disc Drive), an SSD (Solid State Drive), or the like. The storage unit 204 stores image data received from the first printer controller 101, data regarding the amount of ink droplets ejected from the nozzle group in the plurality of recording heads 242 (ink ejection amount data), and the like.

Further, the first image forming apparatus 20 includes a paper transport unit 210, an operation display unit 220, a communication I / F (Interface) unit 230, an image forming unit 240, and the like.

The paper transport unit 210 transports paper by driving a transport system mechanism such as a transfer unit 22 and a paper discharge unit 26 (see FIG. 2).

The operation display unit 220 includes, for example, a panel-type display device (an example of a notification unit) such as a liquid crystal display (LCD) or an organic EL (Electro Luminescence) display device, and a position input device such as a touch pad. It is composed of a touch panel that combines the above. The operation display unit 220 displays an instruction menu for the user, information on the acquired image data, and the like. The display device of the operation display unit 220 is notified of an abnormality (for example, when the first control device 102 detects the occurrence of an abnormality in the first image reading device 30 or the second image reading device 60). Notification) etc. are displayed.

The communication I / F unit 230 is connected to the first printer controller 101. Then, the communication I / F unit 230 receives the image data from the first printer controller 101, and supplies the received image data to the control unit 200 via the system bus B1.

The image forming unit 240 forms an image on the surface of the paper based on the image data transmitted from the first printer controller 101. When the data for the surface adjustment chart is transmitted from the first printer controller 101, the surface adjustment chart is formed on the surface of the paper. The head drive unit 241 in the head unit 24 drives the recording head 242. Since the other parts constituting the image forming unit 240 have already been described with reference to FIG. 2, the description thereof will be omitted here.

<Configuration of control system of first image reader>
Next, the configuration of the control system of the first image reading device 30 will be described with reference to FIG. FIG. 6 is a block diagram showing a configuration example of the control system of the first image reading device 30. Since the configuration of the control system of the second image reading device 60 is the same as the configuration of the control system of the first image reading device 30, only the configuration of the control system of the first image reading device 30 will be described here. However, the description of the configuration of the control system of the second image reading device 60 will be omitted.

As shown in FIG. 6, the first image reading device 30 includes a control unit 300. The control unit 300 includes, for example, a CPU 301, a RAM 302 used as a work area of the CPU 301, a ROM 303 for storing a program or the like executed by the CPU 301, and the like.

The CPU 301 of the control unit 300 is connected to each unit constituting the first image reading device 30 via the system bus B3, and controls the operation of each unit. Further, the control unit 300 includes a storage unit 304 or the like as a large-capacity storage device including an HDD, an SSD, or the like.

Further, the first image reading device 30 includes a paper transport unit 310, a communication I / F unit 320, an in-line sensor 330, and the like.

The paper transport unit 310 drives a mechanism of a transport system (not shown). The communication I / F unit 320 is connected to the first control device 102. Then, the communication I / F unit 320 receives the control signal transmitted from the first control device 102, and transmits the read image read by the inline sensor 330 to the first control device 102.

The in-line sensor 330 is, for example, a line sensor in which a plurality of detection elements are arranged in the width direction (main scanning direction) of the paper. The in-line sensor 330 can acquire an image formed on paper for each of a plurality of wavelength components, for example, three wavelengths of red (R), green (G), and blue (B). The in-line sensor 330 reads the entire surface of one page of the paper on which the image such as the surface adjustment chart is formed, and outputs the read image to the control unit 300.

Since the white correction plate 332 has already been described with reference to FIG. 4, the description thereof will be omitted here.

<Configuration of control system of the first printer controller>
Next, the configuration of the control system of the first printer controller 101 will be described with reference to FIG. 7. FIG. 7 is a block diagram showing a configuration example of the control system of the first printer controller 101. Since the configuration of the second printer controller 103 is the same as the configuration of the first printer controller 101, only the configuration of the first printer controller 101 will be described here, and the configuration of the second printer controller 103 will be described. Is omitted.

As shown in FIG. 7, the first printer controller 101 includes a control unit 110. The control unit 110 includes, for example, a CPU 111, a RAM 112 used as a work area of the CPU 111, a ROM 113 for storing a program or the like executed by the CPU 111, and the like.

The CPU 111 of the control unit 110 is connected to each unit constituting the first printer controller 101 via the system bus B5, and controls the operation of each unit. Further, the CPU 111 controls not to reverse the paper with respect to the paper reversing unit 40 (see FIG. 1) connected via the communication I / F unit 115 based on the control (instruction) by the first control device 102. Also do.

Further, the control unit 110 includes a storage unit 114 as a large-capacity storage device including an HDD, an SSD, or the like. The storage unit 114 stores image data and the like transmitted to the first image forming apparatus 20.

Further, the first printer controller 101 includes a communication I / F unit 115, an operation input unit 116, a display unit 117, a RIP unit 118, and the like.

The communication I / F unit 115 is connected to the first image forming apparatus 20, and transmits the image data or the like generated by the RIP unit 118 to the first image forming apparatus 20. Further, the communication I / F unit 115 is also connected to the first control device 102, and receives surface adjustment data, a notification notifying the failure of the first image reading device 30, and the like from the first control device 102. do.

Further, the communication I / F unit 115 is also connected to the second control device 104, and receives surface adjustment data from the second control device 104. Further, the communication I / F unit 115 is also connected to the paper reversing unit 40, and transmits a control signal or the like instructing the paper reversing unit 40 not to invert the paper.

The operation input unit 116 is composed of, for example, a keyboard, a mouse, or the like, and has a role as an input unit that receives various instructions, characters, numbers, and other data input by the user's operation. The display unit 117 is a panel-type display device such as a liquid crystal display device or an organic EL display device, and displays an instruction menu for the user, information on acquired image data, and the like.

The RIP unit 118 performs RIP processing on the drawing data included in the print job transmitted from the terminal device (not shown) to generate image data such as surface adjustment chart data.

<Structure of control system of first control device>
Next, the configuration of the control system of the first control device 102 will be described with reference to FIG. FIG. 8 is a block diagram showing a configuration example of the control system of the first control device 102.

As shown in FIG. 8, the first control device 102 includes a control unit 120. The control unit 120 includes, for example, a CPU 121, a RAM 122 used as a work area of the CPU 121, a ROM 123 for storing a program or the like executed by the CPU 121, and the like.

The CPU 121 of the control unit 120 is connected to each unit constituting the first control device 102 via the system bus B7, and controls the operation of each unit. For example, the CPU 121 performs the following control when performing the image reading device abnormality presence / absence determination process.

(1) Control for transmitting a control signal or the like instructing the paper reversing unit 40 not to invert the paper.
(2) Control to prevent the second image forming apparatus 50 from forming the back side adjustment chart on the paper by not causing the second printer controller 103 to generate the back side adjustment data.
(3) Control to cause the second image reading device 60 to read the surface adjustment chart.
(4) A control for causing the second control device 104 to generate surface adjustment data based on a read image of the surface adjustment chart.

Further, the CPU 121 performs an abnormality presence / absence determination process for determining the presence / absence of an abnormality in the first image reading device 30 or the second image reading device 60. In the abnormality presence / absence determination process of the image reading device, the CPU 121 first generates surface adjustment data (first surface adjustment data) generated by the first control device 102 based on the image read by the surface adjustment chart by the first image reading device 30. Based on (an example of an example of the reading result of the image), the ejection state (hereinafter, also referred to as “first nozzle state”) of the nozzle of the recording head 242 (see FIG. 3) of the first image forming apparatus 20 is determined.

Further, the CPU 121 is based on the surface adjustment data (an example of the reading result of the first image) generated by the second control device 104 based on the image read by the surface adjustment chart by the second image reading device 60. Therefore, the ejection state of the nozzle of the recording head 242 of the first image forming apparatus 20 (hereinafter, also referred to as “second nozzle state”) is determined.

Then, the CPU 121 determines whether or not an abnormality has occurred in the first image reading device 30 or the second image reading device 60 by comparing the first nozzle state and the second nozzle state. When the CPU 121 determines that an abnormality has occurred in the first image reading device 30 or the second image reading device 60, the CPU 121 displays the fact on the display device of the operation display unit 220 to indicate the occurrence of the abnormality. It also controls to notify the user.

With the occurrence of an abnormality, for example, there is a possibility that deposits are attached to the image reading surface 331 or the white correction plate 332 of the first image reading device 30 and the image reading surface or the white correction plate of the second image reading device 60. May also be notified and a message urging the cleaning of these surfaces may be notified together.

Further, the control unit 120 includes a storage unit 124 as a large-capacity storage device including an HDD, an SSD, or the like. The storage unit 124 stores a surface-read image or the like received from the first image reading device 30.

Further, the first control device 102 includes a communication I / F unit 125, an operation input unit 126, a display unit 127, an adjustment data generation unit 128 (an example of the first adjustment data generation unit), and the like.

The communication I / F unit 125 is connected to the first image reading device 30 and receives the surface reading image transmitted from the first image reading device 30. Further, the communication I / F unit 125 is also connected to the first printer controller 101, and transmits the adjustment data and the like generated by the adjustment data generation unit 128 to the first printer controller 101.

The operation input unit 126 is composed of, for example, a keyboard, a mouse, or the like, and has a role as an input unit that receives various instructions, characters, numbers, and other data input by the user's operation. The display unit 127 is a panel-type display device such as a liquid crystal display device or an organic EL display device, and displays an instruction menu for the user, information on acquired image data, and the like.

The adjustment data generation unit 128 generates surface adjustment data (example of first image adjustment data) based on the scanned image transmitted from the first image reading device 30. In the surface adjustment data, correction for nozzle ejection failure of the recording head 242 (see FIG. 3), head tilt adjustment, nozzle overlap adjustment, voltage adjustment for adjusting the amount of ink ejection, and voltage adjustment between the same colors. Adjustment in the main scanning direction / sub-scanning direction, gamma correction, shading correction, etc. are instructed.

The configuration of the control system of the second control device 104 is almost the same as the configuration of the control system of the first control device 102, but the communication I / F unit is the second image reading device 60 and the second printer. It differs from the first control device 102 in that it is connected not only to the controller 103 but also to the first printer controller 101. When the control unit of the second control device 104 performs the image reading device abnormality presence / absence determination process by the first control device 102, the control unit generates surface adjustment data based on the read image of the surface adjustment chart, and the control unit for the surface. The adjustment data is transmitted to the first printer controller 101 via the communication I / F unit.

<Structure of scanned image of surface adjustment data generated by each of the first image reading device and the second image reading device>
Next, with reference to FIGS. 9 to 12, the configuration of the read image of the head image read by each of the first image reading device 30 and the second image reading device 60 will be described. The head image is an image printed for the purpose of confirming whether or not each nozzle constituting the recording head 242 (see FIG. 3) is clogged.

In the head image, for example, the odd-numbered row and the even-numbered row of the nozzles of the recording head 242 (see FIG. 3) are divided into upper and lower sides in one head image, respectively, and further, the upper side and the lower side are also divided into several stages. It is generated by ejecting ink separately. By confirming the read image of the head image generated in this way, the first control device 102 can confirm the ink ejection state in each nozzle constituting the recording head 242.

FIG. 9 shows the head in the case where the image reading surface 331 or the white correction plate 332 of the first image reading device 30 and the image reading surface or the white correction plate of the second image reading device 60 have no deposits. It is a figure which shows the structural example of the scanned image of. FIG. 10 is a diagram showing a configuration example of a read image of a head image when an deposit is attached to the image reading surface 331 or the white correction plate 332 of the first image reading device 30.

FIG. 11 is a diagram showing a configuration example of a read image of a head image when an deposit is attached to the image reading surface or the white correction plate (not shown) of the second image reading device 60. FIG. 12 is a diagram showing an example of a scanned image of a head image for confirming a nozzle ejection defect based on the surface adjustment data shown in FIG. 9 or FIG. The X direction in FIGS. 9 to 12 indicates the main scanning direction (paper transport direction) of the first image forming apparatus 20 or the second image forming apparatus 50, and the Y direction indicates the first image forming apparatus 20. Alternatively, the sub-scanning direction (paper width direction) of the second image forming apparatus 50 is shown.

FIG. 9A shows an example of a read image of the head image read by the first image reading device 30, and FIG. 9B shows an example of the read image of the head image read by the second image reading device 60. show.

9A and FIGS. 9A and FIGS. 9A and FIGS. 9A and FIGS. 9A and FIG. As shown in 9B, the ink ejection state in each nozzle becomes uniform.

Here, for example, it is assumed that a ejection defect has occurred in three specific nozzles of the recording head 242 when printing the surface adjustment chart. In this case, in the surface adjustment chart, three image quality defects indicating nozzle ejection defects occur. As a result, in both the image read by the first image reading device 30 (FIG. 9A) and the image read by the second image reading device 60 (FIG. 9B), the corresponding nozzle has a ejection failure. Three pixels appear in which it is assumed that the above is generated.

That is, the number of nozzle ejection defects determined based on the image read by the first image reading device 30 (hereinafter, also referred to as "number of first nozzle ejection defects": an example of the first nozzle state. ) And the number of nozzle ejection defects determined based on the image read by the second image reading device 60 of the head image (hereinafter referred to as "the number of nozzle ejection defects": the second nozzle state. One example) is the same number (3).

On the other hand, when the image reading surface 331 or the white correction plate 332 of the first image reading device 30 has an deposit, the image read by the first image reading device 30 of the head image is shown in 10A. The image read by the second image reading device 60 of the head image is as shown in 10B.

That is, as shown in FIG. 10A, vertical streaks occur in the image read by the first image reading device 30 with deposits. On the other hand, in the image read by the second image reading device 60 without deposits, which is shown in FIG. 10B, no vertical streaks are generated. In this case, the number of first nozzle ejection defects is smaller than the number of second nozzle ejection defects.

Further, when an deposit is attached to the image reading surface or the white correction plate of the second image reading device 60, vertical streaks occur in the head image read image by the second image reading device 60 shown in FIG. 11B. do. On the other hand, in the image read by the first image reading device 30 without deposits, which is shown in FIG. 11A, no vertical streaks are generated. Therefore, the number of second nozzle ejection defects generated is smaller than the number of first nozzle ejection defects.

However, when the nozzle ejection failure actually occurs in the recording head 242 of the second image forming apparatus 50, the number of nozzle ejection defects generated in the first nozzle (determined based on the adhesion of deposits) and the second nozzle There is a possibility that the number of ejection defects (actual ejection defects actually occur) will be the same by chance.

For example, the number of the nozzle where the ejection defect has occurred detected from the image read by the first image reading device 30 (hereinafter, also referred to as “first ejection defect occurrence nozzle number”: first nozzle). An example of the state) is assumed to be "1", "23", "45", "1369", and "2486". Then, the number of the nozzle where the ejection defect has occurred detected from the image read by the second image reading device 60 (hereinafter, also referred to as “second ejection defect occurrence nozzle number”: second nozzle). An example of the state) is assumed to be "54", "76", "387", "2619", and "3751". In this case, the number of first nozzle ejection defects and the number of second nozzle ejection defects are both five, which is the same number. However, in this case, the first ejection defect occurrence nozzle number and the first ejection defect occurrence nozzle number are different.

In the present embodiment, the control unit 120 of the first control device 102 includes the number of first nozzle ejection defects and the number of second nozzle ejection defects, the number of the first nozzle ejection defects and the second ejection defects. Based on the generated nozzle number and the occurrence nozzle number, the abnormality presence / absence determination process of the image reading device is performed. Specifically, the control unit 120 of the first control device 102 detects a larger number of occurrences when the number of occurrences of the first nozzle ejection failure and the number of occurrences of the second nozzle ejection failure are different. It is determined that an abnormality such as adhesion of deposits has occurred in the image reading device that generated the scanned image.

Further, when the number of first nozzle ejection defects and the number of second nozzle ejection defects are the same, the control unit 120 of the first control device 102 determines the number of the first nozzle ejection defects. , It is determined whether or not the nozzle number where the second ejection defect occurs matches. Then, when the first ejection defect occurrence nozzle number and the second ejection defect occurrence nozzle number match, the control unit 120 of the first control device 102 has the image reading surface 331 of the first image reading device 30. Alternatively, it is determined that no deposits have adhered to either the white correction plate 332 and the image reading surface or the white correction plate of the second image reading device 60.

On the other hand, even if the number of first nozzle ejection defects and the number of second nozzle ejection defects are the same, the first nozzle defect occurrence nozzle number and the second ejection defect occurrence nozzle number do not match. In this case, the control unit 120 of the first control device 102 is attached to the image reading surface 331 or the white correction plate 332 of the first image reading device 30 or the image reading surface or the white correction plate of the second image reading device 60. , It is determined that deposits are attached.

Next, referring to FIG. 12, the nozzle ejection based on the surface adjustment data is actually performed even though the image reading surface 331 or the white correction plate 332 of the first image reading device 30 has deposits. An example of a scanned image of a head image for checking a defect will be described. When it is erroneously determined that a nozzle ejection defect has occurred even though the image reading surface 331 or the white correction plate 332 of the first image reading device 30 has an adhering matter, the correction for the nozzle ejection defect is made. Will be done. Specifically, complementation is performed such as increasing the amount of ink ejected from a nozzle adjacent to the nozzle determined to have a ejection defect.

As a result, as seen in the portion surrounded by the alternate long and short dash line in FIG. 12, the ink ejection regions are connected to each other. When such overcorrection is performed, vertical streaks (not shown) appear along the sub-scanning direction in the image formed on the paper by the image forming unit 240. In this embodiment, we propose a method to prevent such erroneous determination.

<Image quality adjustment method using an image formation system>
[Image quality adjustment method during normal operation]
Next, with reference to FIG. 13, the procedure of the image quality adjusting method by the image forming system 1 according to the present embodiment will be described. FIG. 13 is a flowchart showing an example of a procedure of an image quality adjusting method in a normal time by the image forming system 1. The normal time is a case where the job is normally executed without detecting an abnormality or the like. The image quality adjustment process of FIG. 13 is performed after the test printing performed prior to the actual printing.

First, the first printer controller 101 starts the image quality adjustment process based on the image quality adjustment job transmitted from the terminal device (not shown) (step S1). Next, the paper feeding device 10 (see FIG. 1) starts feeding to the first image forming device 20 (step S2). Next, the RIP unit 118 (see FIG. 7) of the first printer controller 101 generates data for the surface adjustment chart (step S3).

Next, the image forming unit 240 (see FIG. 5) of the first image forming apparatus 20 prints the surface adjustment chart on the surface of the paper (step S4). Next, the in-line sensor 330 (see FIG. 6) of the first image reading device 30 reads the surface adjustment chart printed on the paper (step S5). After that, the reading result of the surface adjustment chart is transmitted from the first image reading device 30 to the first control device 102. Before reading the surface adjustment chart, shading correction using the white correction plate 332 (see FIG. 4) is performed based on the control by the control unit 300 of the first image reading device 30. ..

Next, the adjustment data generation unit 128 (see FIG. 8) of the first control device 102 generates surface adjustment data based on the reading result of the surface adjustment chart (step S6). Next, the communication I / F unit 125 of the first control device 102 transmits the surface adjustment data to the first printer controller 101 (step S7).

Next, the paper reversing unit 40 (see FIG. 1) reverses the front and back surfaces of the paper conveyed from the first image reading device 30 (step S8). Next, the RIP unit (not shown) of the second printer controller 103 generates backside adjustment chart data (step S9). Next, the image forming unit (not shown) of the second image forming apparatus 50 forms the back surface adjustment chart on the back surface of the paper (step S10).

Next, the in-line sensor (not shown) of the second image reading device 60 reads the back surface adjustment chart (step S11). Next, the adjustment data generation unit (not shown) of the second control device 104 generates back surface adjustment data based on the reading result of the back surface adjustment chart (step S12). Next, the communication I / F unit (not shown) of the second control device 104 transmits the backside adjustment data to the second printer controller 103 (step S13). Next, the paper is conveyed to the purge tray 72 of the paper ejection device 70 (see FIG. 1) (step S14).

[Image formation method in normal times]
Next, with reference to FIG. 14, an example of the image forming process by the image forming system 1 after the image quality adjustment is performed will be described. FIG. 14 is a flowchart showing an example of image formation processing by the image formation system 1 after the image quality adjustment is performed. First, the first printer controller 101 starts a job based on a normal job transmitted from a terminal device (not shown) (step S15). Next, the first image forming apparatus 20 performs job-based printing (production printing) (step S16). Since the above-mentioned image quality adjustment process is properly performed, no abnormality occurs during printing based on the job, and the job is output normally.

[Conventional image quality adjustment method when an abnormality occurs in the image reader]
Next, with reference to FIG. 15, a procedure of an image quality adjusting method when an abnormality has occurred in an image reading device by a conventional image forming system will be described. FIG. 15 is a flowchart showing an example of a procedure of an image quality adjusting method when an abnormality has occurred in an image reading device by a conventional image forming system. The conventional image forming system also has the same configuration as the image forming system 1 according to the present embodiment shown in FIG.

First, the first printer controller 101 starts the image quality adjustment process based on the image quality adjustment job transmitted from the terminal device (not shown) (step S21). Next, the paper feeding device 10 starts feeding to the first image forming device 20 (step S22). Next, the RIP unit 118 of the first printer controller 101 generates data for the surface adjustment chart (step S23).

Next, the image forming unit 240 of the first image forming apparatus 20 prints the surface adjustment chart on the surface of the paper (step S24). Next, the in-line sensor 330 of the first image reading device 30 reads the surface adjustment chart (step S25). After that, the reading result of the surface adjustment chart is transmitted from the first image reading device 30 to the first control device 102. It is assumed that the reading result obtained at this time indicates that streaks, stains, etc. have been detected.

Next, the adjustment data generation unit 128 of the first control device 102 generates surface adjustment data based on the reading result of the surface adjustment chart (step S26). Next, the communication I / F unit 125 of the first control device 102 transmits the surface adjustment data to the first printer controller 101 (step S27). Here, the surface adjustment data sent to the first printer controller 101 is adjustment data that has been corrected for nozzle ejection defects based on the detection of streaks, stains, and the like.

Since the processes from step S28 to step S34 are the same as the processes from step S8 to step S14 in FIG. 13, the description of these steps will be omitted.

[Conventional image formation method when there is a false detection of nozzle ejection failure]
Next, with reference to FIG. 16, an example of the image forming process by the image forming system 1 after the image quality adjustment is performed will be described. FIG. 16 is a flowchart showing an example of image formation processing by the image formation system 1 after the image quality adjustment is performed. First, the first printer controller 101 starts a job based on a normal job transmitted from a terminal device (not shown) (step S35). Next, the first image forming apparatus 20 performs printing (production printing) based on the job (step S36). The image printed at this time is an image overcorrected by the adjustment data for nozzle ejection defect correction generated based on the detection result of streaks, stains, and the like. Therefore, vertical streaks appear in the printed image.

Then, the cause is investigated by the user (step S37). In other words, if the user finds a vertical streak in the printed image produced by production printing after adjusting the image quality, the user investigates where the cause is. Next, the user detects that an deposit is attached to the surface of the image reading surface 331 or the white correction plate 332 of the first image reading device 30 (step S38).

That is, in the conventional method, despite the occurrence of an abnormality such as adhesion on the surface of the image reading surface 331 or the white correction plate 332 of the first image reading device 30, nozzle ejection failure occurs. If it is falsely detected as occurring, overcorrection will be performed. As a result, vertical streaks occur in the printed matter produced by the actual printing after the image quality adjustment is performed. The user will find this vertical streak when performing production printing, and it will take time to investigate the cause.

[Image quality adjustment method]
Next, with reference to FIG. 17, the procedure of the image quality adjusting method by the image forming system 1 according to the present embodiment will be described. FIG. 17 is a flowchart showing an example of the procedure of the image quality adjusting method by the image forming system 1.

First, the first printer controller 101 starts the image quality adjustment process based on the image quality adjustment job transmitted from the terminal device (not shown) (step S41). Next, the paper feeding device 10 starts feeding to the first image forming device 20 (step S42). Next, the RIP unit 118 of the first printer controller 101 generates data for the surface adjustment chart (step S43).

Next, the image forming unit 240 of the first image forming apparatus 20 prints the surface adjustment chart on the surface of the paper (step S44). Next, the in-line sensor 330 of the first image reading device 30 reads the surface adjustment chart (step S45). After that, the reading result of the surface adjustment chart is transmitted from the first image reading device 30 to the first control device 102.

Next, the adjustment data generation unit 128 of the first control device 102 generates surface adjustment data based on the reading result of the surface adjustment chart (step S46). It is assumed that the reading result obtained at this time indicates that streaks, stains, etc. have been detected. Next, the communication I / F unit 125 of the first control device 102 transmits the surface adjustment data to the first printer controller 101 (step S47).

Next, the paper reversing unit 40 (see FIG. 1) passes the paper as it is without reversing it, and conveys it to the second image forming apparatus 50 (step S48). Next, the second image reading device 60 reads the surface adjustment chart printed on the paper (step S49). Next, the adjustment data generation unit (not shown) of the second control device 104 generates surface adjustment data based on the reading result of the surface adjustment chart (step S50).

Next, the communication I / F unit (not shown) of the second control device 104 transmits the surface adjustment data to the first control device 102 (step S51). Here, the surface adjustment data sent to the first control device 102 is adjustment data that has been corrected for nozzle ejection defects based on the detection of streaks, stains, and the like. Next, the paper is conveyed to the purge tray 72 of the paper ejection device 70 (step S52). Next, the first control device 102 performs an abnormality presence / absence determination process of the image reading device (step S53). The abnormality presence / absence determination process of the image reading device by the first control device 102 will be described in detail with reference to FIG. 18 below.

[Processing for determining whether or not there is an abnormality in the image reading device by the first control device]
Next, with reference to FIG. 18, the procedure of the abnormality presence / absence determination processing of the image reading device by the first control device 102 will be described. FIG. 18 is a flowchart showing an example of abnormality presence / absence determination processing of the image reading device by the first control device 102.

First, the control unit 120 of the first control device 102 has the number of nozzle ejection defects generated in the first nozzle (the number of ejection failure nozzles in the first image forming apparatus 20 detected by the first image reading device 30) and the second. It is determined whether or not the number of nozzle ejection defects (the number of nozzle ejection defects in the first image forming apparatus 20 detected by the second image reading device 50) is the same as the number of nozzle ejection defects (step S61). The control unit 120 of the first control device 102 detects the number of nozzle ejection defects generated in the first nozzle using the surface adjustment data generated by the adjustment data generation unit 128. Further, the control unit 120 of the first control device 102 detects the number of nozzle ejection defects generated by using the surface adjustment data generated by the adjustment data generation unit of the second control device 104.

When it is determined in step S61 that the number of occurrences of the first nozzle ejection failure and the number of occurrences of the second nozzle ejection failure are the same (when the determination in step S61 is YES), the control unit 120 is the first. Whether or not the nozzle number for which the ejection defect has occurred (the nozzle number for the ejection defect in the first image forming apparatus 20) and the nozzle number for which the second ejection defect has occurred (the nozzle number for the ejection defect in the second image forming apparatus 50) match. (Step S62).

When it is determined in step S62 that the first ejection failure occurrence nozzle number and the second ejection failure occurrence nozzle number match (when the determination in step S62 is YES), the control unit 120 is the first. In the image reading device 30, it is determined that no abnormality such as adhesion of deposits such as dust has occurred (step S63).

On the other hand, when it is determined in step S62 that the first ejection failure occurrence nozzle number and the second ejection failure occurrence nozzle number do not match (when the determination in step S62 is NO), the control unit 120 determines. It is determined that an abnormality such as adhesion of deposits has occurred in either the first image reading device 30 or the second image reading device 60 (step S64).

When it is determined in step S61 that the number of occurrences of the first nozzle ejection failure and the number of occurrences of the second nozzle ejection failure are different (when the determination in step S61 is NO), the control unit 120 controls the first nozzle ejection. It is determined whether or not the number of defects generated is larger than the number of defects generated in the second nozzle ejection (step S65).

When it is determined in step S65 that the number of occurrences of the first nozzle ejection failure is larger than the number of occurrences of the second nozzle ejection failure (when the determination in step S65 is YES), the control unit 120 reads the first image. It is determined that an abnormality such as adhesion of deposits has occurred in the device 30 (step S66). On the other hand, when it is determined that the number of occurrences of the first nozzle ejection failure is smaller than the number of occurrences of the second nozzle ejection failure (when the determination in step S65 is NO), the control unit 120 is the second image reading device 60. In addition, it is determined that an abnormality such as adhesion of adhered matter has occurred (step S67).

In the above-described embodiment, the control unit 120 of the first control device 102 reads the first image by the first image reading device 30 and the first image read by the second image reading device 60. By comparing with and, the abnormality presence / absence determination processing in the first image reading device 30 or the second image reading device 60 is performed. Therefore, according to the present embodiment, it is possible to reduce erroneous determination of the cause of causing vertical streaks without taking time and effort for the user and without increasing the cost of the device.

Further, in the above-described embodiment, when the control unit 120 of the first control device 102 performs the abnormality presence / absence determination process, the surface of the paper on which the surface adjustment chart is formed by the first image forming device 20 is set on the paper. Control is performed so that the inversion unit 40 does not invert and the second image forming apparatus 50 does not form an image. That is, in the present embodiment, since the abnormality presence / absence determination processing in the first image reading device 30 or the second image reading device 60 is performed using each device originally possessed by the image forming system 1, a dedicated device or device is used. There is no need to newly set up such things. Therefore, according to the present embodiment, it is possible to determine the presence or absence of an abnormality in the first image reading device 30 or the second image reading device 60 without increasing the cost of the device.

Further, in the above-described embodiment, the control unit 120 compares the first nozzle state and the second nozzle state in the abnormality presence / absence determination process. As described above, the first nozzle state is the state of the nozzle of the first image forming unit 20 determined by the control unit 120 based on the reading result of the first image by the first image reading device 30. .. Further, as described above, the second nozzle state is the state of the nozzle of the first image forming unit 20 determined by the control unit 120 based on the reading result of the first image by the second image reading unit 60. Is. Therefore, according to the present embodiment, the first image forming unit 20 or the second image forming apparatus has an abnormality even though the first image reading apparatus 30 or the second image reading apparatus 60 has an abnormality. It is possible to prevent erroneous determination that the 50 has an abnormality. That is, according to the present embodiment, it is possible to prevent overcorrection due to erroneous determination.

Further, in the above-described embodiment, the number of first nozzle ejection defects and the number of second nozzle ejection defects, or the number of first nozzle ejection defects, the number of second nozzle ejection defects, and the first ejection are generated. The presence or absence of an abnormality in the first image reading device 30 or the second image reading device 60 is determined based on the defect occurrence nozzle number and the second ejection failure occurrence nozzle number. Therefore, according to the present embodiment, the accuracy of determining the presence or absence of an abnormality in the first image reading device 30 or the second image reading device 60 is improved.

Further, in the above-described embodiment, when the control unit 120 of the first control device 102 determines that an abnormality has occurred in the first image reading device 30 or the second image reading device 60, that fact is determined. The user is notified via the operation display unit 220 of the first image forming apparatus 20. Therefore, according to the present embodiment, the user can quickly take measures against the abnormality.

<Various deformation examples>
The present invention is not limited to the above-described embodiment, and various other application examples and modifications can be taken as long as they do not deviate from the gist of the present invention described in the claims.

In the above-described embodiment, the first control device 102 gives an example of performing the abnormality presence / absence determination process of the image reading device, but the present invention is not limited to this. Instead of the first control device 102, the second control device 104 may perform the abnormality presence / absence determination process of the image reading device.

Further, in the above-described embodiment, the first image forming device 20 and the first image reading device 30 are provided as separate devices, and the second image forming device 50 and the second image reading device 60 are separate. However, the present invention is not limited to this. The first image reading device 30 may be formed integrally with the first image forming device 20, and the second image reading device 60 may be formed integrally with the second image forming device 50.

Further, in the above-described embodiment, an example of applying the image forming apparatus of the present invention (first image forming apparatus 20 and second image forming apparatus 50) to an inkjet type image forming apparatus has been given, but the present invention has been given. Is not limited to this. The image forming apparatus of the present invention is applicable to other image forming apparatus such as an LED (Liquid Crystal Display) printer and an electrophotographic printer, as long as it is an image forming apparatus that conveys paper via a drum, a roller, a belt, or the like. May be done.

1 ... Image forming system, 20 ... First image forming apparatus, 24 ... Head unit, 30 ... First image reading device, 40 ... Paper reversing unit, 50 ... Second image forming apparatus, 60 ... Second image Reading device, 70 ... Paper ejection device, 101 ... First printer controller, 102 ... First control device, 103 ... Second printer controller, 104 ... Second control device, 120 ... Control unit, 128 ... Adjustment data Generation unit, 242 ... Recording head, 320 ... White correction plate, 330 ... In-line sensor, 331 ... Image reading surface

Claims (10)

A first image forming unit that forms a first image on a first surface, which is one surface of a recording material,
A first image reading unit that reads the first image formed by the first image forming unit, and a first image reading unit.
A second image forming portion that forms a second image on the second surface, which is a surface different from the first surface in the recording material,
A second image reading unit that reads the first image or the second image,
With a control unit,
The control unit compares the reading result of the first image by the first image reading unit with the reading result of the first image by the second image reading unit, whereby the first image is read. An image forming apparatus that performs abnormality presence / absence determination processing in the image reading unit or the second image reading unit. The first surface is further provided with a paper reversing section for reversing the surface of the recording material on which the first image is formed.
When the control unit performs the abnormality presence / absence determination process, the control unit controls not to invert the surface of the recording material on which the first image is formed in the first image forming unit to the paper reversing unit, and the first image forming unit. The image forming apparatus according to claim 1, wherein the image forming unit of 2 is controlled so as not to form the second image. The first image forming unit and the second image forming unit each include a plurality of recording heads having a plurality of nozzles.
The control unit is the state of the nozzle of the first image forming unit determined based on the reading result of the first image by the first image reading unit in the abnormality presence / absence determination process. A claim for comparing the nozzle state with the second nozzle state, which is the state of the nozzle of the first image forming unit, which is determined based on the reading result of the first image by the second image reading unit. Item 2. The image forming apparatus according to Item 2. The first nozzle state determined by the control unit is detected based on the reading result of the first image by the first image reading unit, and a ejection defect occurs in the first image forming unit. The second nozzle state is represented by the number of first nozzle ejection defects, which is the number of nozzles, and the second nozzle state is detected based on the reading result of the first image by the second image reading unit. It is represented by the number of second nozzle ejection defects, which is the number of nozzles in which the ejection defects have occurred in the image forming portion of 1.
When the number of occurrences of the first nozzle ejection failure and the number of occurrences of the second nozzle ejection failure are different from each other, the control unit causes an abnormality in the first image reading unit or the second image reading unit. The image forming apparatus according to claim 3. In the first nozzle state detected by the control unit, a ejection failure occurs in the first image forming unit detected based on the reading result of the first image by the first image reading unit. It is represented by the number of first nozzle ejection defects, which is the number of nozzles, and the first nozzle number, which is the number of the nozzles in which the ejection defects occur, and the second nozzle state is A second nozzle ejection defect occurrence, which is the number of nozzles in which the ejection defect has occurred in the first image forming portion, detected based on the reading result of the first image by the second image reading unit. It is represented by the number and the number of the second nozzle with the ejection defect, which is the number of the nozzle with the ejection defect.
In the control unit, the number of the first nozzle ejection defects and the number of the first nozzle ejection defects are the same, and the first ejection defect occurrence nozzle number and the first ejection defect occur. The image forming apparatus according to claim 4, wherein it is determined that no abnormality has occurred in the first image reading unit and the second image reading unit when the defect occurrence nozzle numbers match. In the control unit, the number of the first nozzle ejection defects and the number of the first nozzle ejection defects are the same, and the first ejection defect occurrence nozzle number and the second ejection defect occur. The image forming apparatus according to claim 5, wherein when the defect occurrence nozzle number is different, it is determined that an abnormality has occurred in the first image reading unit or the second image reading unit. Based on the reading result of the first image by the first image reading unit, the first image adjustment data including the correction for ejection failure in the nozzle of the first image forming unit is generated. Adjustment data generator and
Based on the reading result of the first image by the second image reading unit, a second image adjustment data including a correction for ejection failure in the nozzle of the first image forming unit is generated. With the adjustment data generator,
The control unit compares the detected first nozzle state determined using the first image adjustment data with the second nozzle state determined using the second image adjustment data. The image forming apparatus according to any one of claims 3 to 6, wherein the presence or absence of an abnormality in the first image reading unit or the second image reading unit is determined. The cause of the abnormality in the first image reading unit is the adhesion of the image reading surface of the first image reading unit to the image reading surface, and the first image reading when the shading correction of the first image reading unit is performed. It is at least one of the deposits on the white correction plate read by the unit and the defect of a specific cell among the plurality of cells possessed by the first image reading unit, and is the second image reading unit. The cause of the abnormality is the deposit on the image reading surface of the image reading surface of the second image reading unit, and the white correction plate read by the second image reading unit during the shading correction of the second image reading unit. The image formation according to any one of claims 3 to 6, which is at least one of the defects of a specific cell among the plurality of cells possessed by the second image reading unit and the deposits on the image. Device. It also has a notification unit that notifies the user.
7. When the control unit determines that an abnormality has occurred in the first image reading unit or the second image reading unit, the control unit notifies the user to that effect via the notification unit. Or the image forming apparatus according to 8. A first image forming unit that forms a first image on a first surface that is one surface of a recording material, and a first image reading that reads the first image formed by the first image forming unit. A second image forming unit that forms a second image on a second surface that is different from the first surface of the recording material, and a second image that reads the first image or the second image. This is a method for determining the occurrence of an abnormality in an image reading unit by an image forming apparatus including an image reading unit and a control unit.
The control unit compares the reading result of the first image by the first image reading unit with the reading result of the first image by the second image reading unit, whereby the first image is read. A method for determining the presence or absence of an abnormality in an image reading unit, which comprises a procedure for performing an abnormality presence / absence determination process in the image reading unit or the second image reading unit.

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