Image forming device

Abstract

To enable an image area in a recording medium which a user can utilize to be increased.SOLUTION: An image forming device comprises: extracting means that extracts an image for position-sensing from image data in a job; first image forming means that forms the image for position-sensing on a recording medium; sensing means that senses the image for position-sensing formed by the first image forming means; and detecting means that detects a correction amount of an image formation position of second image forming means arranged at a downstream side in a conveying direction of the recording medium with respect to the first image forming means, from a position of the image for position-sensing sensed by the sensing means and a position of an image for position-sensing in the image data.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] Patent document 1 discloses a recording device including a plurality of recording heads arranged in parallel across the width of the recording medium in a direction perpendicular to the transport direction in which the recording medium is transported, and which record an image across the width of the recording medium, a pattern recording means which repeatedly records a predetermined pattern, a reading means which is arranged upstream of each of the recording heads in the transport direction of the recording medium, and which reads the predetermined pattern recorded by the pattern recording means, an adjustment means which adjusts the recording position of the recording head in a direction perpendicular to the transport direction of the recording head, and a control means which controls the adjustment means to adjust the recording position by the adjustment means based on the reading result of the reading means.

[0003] Patent Document 2 describes a plurality of image forming means provided for each color that forms a color image on a recording medium by performing main scanning and sub-scanning, a control means that controls the plurality of image forming means so that an image based on image data is formed, and also controls the plurality of image forming means so that a registration mark is formed that includes a first registration mark in which deviation in the main scanning direction does not appear in the sub-scanning direction and a second registration mark in which deviation in the main scanning direction appears in the sub-scanning direction, each of the first registration mark and the second registration mark having a reference color mark and a mark of another color different from the reference color that is spaced a predetermined distance in the sub-scanning direction from the reference color mark, a reading means that reads the first registration mark and the second registration mark formed on the recording medium, and The image forming apparatus disclosed includes a first calculation means for calculating a correction amount in the sub-scanning direction using a deviation amount in the sub-scanning direction of the mark of the other color for a first registration mark based on the reading result of the reading means, a second calculation means for calculating a correction amount in the main scanning direction using the deviation amount in the sub-scanning direction of the mark of the other color for the first registration mark based on the reference color mark and the deviation amount in the sub-scanning direction of the mark of the other color for a second registration mark based on the reference color mark based on the reading result of the reading means, and an image forming position correction means for correcting an image forming position based on the image data based on the correction amounts calculated by the first calculation means and the second calculation means.

[0004] Patent document 3 discloses an image forming device that includes a receiving means for receiving a print job, an image forming means for recording an image on paper, an extraction means for extracting a partial image from the normal image of the print job formed by the image forming means that can be used as a patch for density detection, and an image reading means for reading image density information of the partial image extracted and fixed to the paper, and that performs image quality adjustment based on the image density information of the read partial image. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2005-35083 A [Patent Document 2] JP 2007-322722 A [Patent Document 3] JP 2014-10422 A Summary of the Invention [Problem to be solved by the invention]

[0006] In a configuration in which a mark dedicated to detection is formed on a recording medium and the mark is detected to adjust the color registration, an area for forming the mark needs to be provided on the recording medium, which reduces the image area on the recording medium that is available to the user.

[0007] An object of the present invention is to make it possible to increase the image area on the recording medium that is available to the user, compared to a configuration in which a mark dedicated to detection is formed on the recording medium. [Means for solving the problem]

[0008] The first aspect has an extraction means for extracting an image for position detection from image data of a job, a first image forming means for forming the image for position detection on a recording medium, a detection means for detecting the image for position detection formed by the first image forming means, and a detection means for detecting a correction amount of an image formation position of a second image forming means arranged downstream in the transport direction of the recording medium relative to the first image forming means, based on the position of the image for position detection detected by the detection means and the position of the image for position detection in the image data.

[0009] In a second aspect, the detection means is a first detection means arranged downstream in the transport direction relative to the first image forming means and upstream in the transport direction relative to the second image forming means, and a second detection means for detecting the image for position detection formed by the first image forming means is arranged downstream in the transport direction of the second image forming means, and the detection means detects a correction amount for the formation position of a third image forming means downstream in the transport direction of the second detection means from the position of the image for position detection detected by the second detection means and the position of the image for position detection in the image data.

[0010] In a third aspect, the extraction means extracts a single image constituted only by the image formed by the first image formation means as the image for position detection.

[0011] In a fourth aspect, when the image data of the job does not include the single image, the extraction means extracts a first image formed by the first image forming means and a second image formed by the second image forming means as images for position detection, and the detection means detects a correction amount for the formation position of the second image forming means from the position of the first image detected by the first detection means and the position of the first image in the image data, and detects a correction amount for the formation position of the third image forming means from the position of the second image detected by the second detection means and the position of the second image in the image data.

[0012] In a fifth aspect, the extraction means extracts a processing mark as an image for position detection.

[0013] In a sixth aspect, when the image data includes a mark for processing, the extraction means extracts the mark for processing with priority over other images.

[0014] In a seventh aspect, the detection means is arranged downstream in the transport direction relative to the second image forming means, the extraction means extracts a first image formed by the first image forming means and a second image formed by the second image forming means as images for position detection, and the detection means detects a correction amount for the formation position of the second image forming means from the difference between the position of the first image detected by the detection means and the position of the first image in the image data, and the difference between the position of the second image detected by the detection means and the position of the second image in the image data.

[0015] In an eighth aspect, the detection means has a length equal to or greater than the width of an image area of ​​the recording medium.

[0016] In a ninth aspect, the detection means has a length equal to or greater than the width of the recording medium.

[0017] A tenth aspect has a receiving means for receiving an instruction to designate an image for position detection.

[0018] An eleventh aspect of the present invention has a correction unit that corrects the image forming position based on the amount of correction detected by the detection unit. Effect of the Invention

[0019] According to the first aspect, the image area available to the user is larger than in a configuration in which a mark dedicated to detection is formed on a recording medium.

[0020] According to the configuration of the second aspect, the image formed by the second image forming means and the image formed by the third image forming means can be aligned with respect to the image formed by the first image forming means.

[0021] According to the third aspect, detection errors in the correction amount can be suppressed compared to a configuration in which an image in which the image formed by the first image forming means and the image formed by the second image forming means are superimposed is extracted as an image for position detection.

[0022] According to the configuration of the fourth aspect, the image formed by the second image forming means can be aligned with the image formed by the first image forming means, and the image formed by the third image forming means can be aligned with the image formed by the second image forming means.

[0023] According to the configuration of the fifth aspect, the process of extracting the image for position detection is simpler than in a configuration in which only an image other than the processing mark is extracted as the image for position detection.

[0024] According to the configuration of the sixth aspect, the process of extracting an image for position detection is simpler than in a configuration in which other images are preferentially extracted.

[0025] According to the seventh aspect, the degree of freedom in arranging the detection means is higher than in a configuration in which the detection means is arranged downstream in the transport direction relative to the first image forming means and upstream in the transport direction relative to the second image forming means.

[0026] According to the configuration of the eighth aspect, the image for position detection can be detected no matter where the image for position detection is formed in the width direction of the image area.

[0027] According to the configuration of the ninth aspect, even if the image for position detection is formed on the recording medium so as to extend beyond the image area, the image for position detection can be detected.

[0028] According to the configuration of the tenth aspect, the user can specify an image for position detection.

[0029] According to the configuration of the eleventh aspect, the image formed by the second image forming means is aligned with the image formed by the first image forming means. [Brief description of the drawings]

[0030] [Figure 1] FIG. 1 is a schematic diagram illustrating a configuration of an inkjet recording apparatus according to a first embodiment. [Diagram 2] 2 is a block diagram showing a hardware configuration of a control device according to the first embodiment. FIG. [Diagram 3]FIG. 2 is a block diagram showing the functional configuration of a CPU according to the first embodiment. [Figure 4] 4 is a flowchart showing a flow of a control process executed by the control device according to the first embodiment. [Diagram 5] 5 is a flowchart showing a flow of an extraction process (step S101 in FIG. 4) executed by the control device according to the first embodiment. [Figure 6] 10 is a diagram showing a state in which an image of image data including processing marks according to the first embodiment is visualized on continuous paper. FIG. [Figure 7] FIG. 2 is a diagram showing a state in which an image of image data according to the first embodiment is decomposed into images of each color. [Figure 8] 11 is a diagram showing a state in which an image of image data including a K single image according to the first embodiment is visualized on continuous paper. FIG. [Figure 9] 11 is a diagram showing a state in which an image of image data including a C single image according to the first embodiment is visualized on continuous paper. FIG. [Figure 10] 11 is a diagram showing a state in which an image of image data including an M single image according to the first embodiment is visualized on continuous paper. FIG. [Figure 11] 5 is a flowchart showing a flow of an example of a correction amount detection process executed by the control device according to the first embodiment. [Figure 12] 5 is a flowchart showing a flow of an example of a correction amount detection process executed by the control device according to the first embodiment. [Figure 13] 10 is a schematic diagram showing a configuration for forming a mark dedicated to detection on continuous paper. FIG. [Figure 14] FIG. 13 is a schematic diagram showing a modified example in which a characteristic portion (a portion having a characteristic shape) of a K image in image data is extracted. [Figure 15] FIG. 11 is a schematic diagram showing the configuration of an inkjet recording apparatus according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. (Inkjet recording device 10) First, we will explain the inkjet recording device 10. Fig. 1 is a schematic diagram showing the configuration of the inkjet recording device 10. In Fig. 1, a side view of the inkjet recording device 10 is shown in the upper part of the page, and a plan view of continuous paper P and detection units 40C, 40M, and 40Y, which will be described later, viewed from above is shown in the lower part of the page.

[0032] The inkjet recording apparatus 10 shown in Fig. 1 is an example of an image forming apparatus that forms an image on a recording medium. Specifically, as shown in Fig. 1, the inkjet recording apparatus 10 is an apparatus that ejects ink droplets onto continuous paper P (an example of a recording medium) to form an image on the continuous paper P. Therefore, the inkjet recording apparatus 10 can also be said to be an example of an ejection apparatus that ejects droplets.

[0033] The continuous paper P is a long recording medium having a length in the transport direction as shown in Fig. 1. Specifically, the continuous paper P is a sheet of paper on which a plurality of pages P1 are arranged along the transport direction.

[0034] 1, the inkjet recording apparatus 10 includes a transport mechanism 20, an image forming unit 30, detection units 40C, 40M, and 40Y, and a control device 50. The specific configurations of each unit of the inkjet recording apparatus 10 (the transport mechanism 20, the image forming unit 30, the detection units 40C, 40M, and 40Y, and the control device 50) will be described below.

[0035] (Transport mechanism 20) The transport mechanism 20 shown in Fig. 1 is a mechanism that transports the continuous paper P. Specifically, as shown in Fig. 1, the transport mechanism 20 has, for example, a plurality of winding rolls 26, an unwinding roll (not shown), and a take-up roll (not shown).

[0036] In the transport mechanism 20, a rotationally driven take-up roll (not shown) takes up the continuous paper P, while an unwinding roll (not shown) unwinds the continuous paper P, thereby transporting the continuous paper P at a predetermined transport speed. The multiple winding rolls 26 are rolls around which the continuous paper P is wound. The multiple winding rolls 26 are wound around the continuous paper P between the unwinding roll (not shown) and the take-up roll (not shown). This determines the transport path of the continuous paper P from the unwinding roll (not shown) to the take-up roll (not shown). In each figure, the transport direction of the continuous paper P (hereinafter sometimes simply referred to as the "transport direction") is indicated by arrow A as appropriate.

[0037] The configuration of the transport mechanism 20 is not limited to the above. For example, the transport mechanism 20 may be a mechanism that transports the continuous paper P from a storage section in which the continuous paper P is stored in a folded state to a storage section in which the continuous paper P is stored so as to be folded. The transport mechanism 20 may also be a mechanism that uses a pair of transport rolls, a transport belt, or the like as a transport member that transports the continuous paper P.

[0038] Furthermore, in this embodiment, continuous paper P is used as the recording medium, but this is not limiting. For example, sheets of paper (that is, cut paper) may be used as the recording medium.

[0039] (Image forming unit 30) The image forming unit 30 shown in Fig. 1 has a function of forming an image on the continuous paper P. Specifically, the image forming unit 30 forms an image by ejecting ink droplets in a non-contact manner onto the continuous paper P transported by the transport mechanism 20. More specifically, the image forming unit 30 has ejection heads 32K, 32C, 32M, and 32Y (hereinafter referred to as 32K to 32Y) as shown in Fig. 1.

[0040] Each of the ejection heads 32K to 32Y is a head that ejects ink droplets. Specifically, each of the ejection heads 32K to 32Y ejects ink droplets of each color, black (K), cyan (C), magenta (M), and yellow (Y), onto the continuous paper P to form an image on the continuous paper P. More specifically, each of the ejection heads 32K to 32Y is configured as follows.

[0041] As shown in Fig. 1, the ejection heads 32K-32Y are arranged in this order toward the downstream side in the transport direction. Each of the ejection heads 32K-32Y has a length in the width direction of the continuous paper P. The width direction of the continuous paper P is a direction that intersects with the transport direction (specifically, a direction perpendicular to the transport direction). In each drawing, the width direction of the continuous paper P (hereinafter sometimes referred to as the "paper width direction") is appropriately indicated by arrow B.

[0042] Each of the ejection heads 32K-32Y has a nozzle surface 30S in which nozzles (not shown) are formed. The nozzle surface 30S of each of the ejection heads 32K-32Y faces downward, and faces, with a gap therebetween, the continuous paper P transported by the transport mechanism 20. Each of the ejection heads 32K-32Y ejects ink droplets from the nozzles (not shown) onto the continuous paper P using a known method such as a thermal method or a piezoelectric method to form an image based on image data.

[0043] The inks used in each of the ejection heads 32K to 32Y include, for example, water-based inks and oil-based inks. Water-based inks contain, for example, a solvent whose main component is water, a colorant (specifically, a pigment, a dye, etc.), and other additives. Oil-based inks contain, for example, an organic solvent, a colorant (specifically, a pigment, a dye, etc.), and other additives.

[0044] As described above, in the image forming unit 30, the ejection heads 32K to 32Y eject ink droplets of each color onto the continuous paper P to form an image on the continuous paper P, so the image forming unit 30 can also be said to be an example of an ejection mechanism that ejects droplets.

[0045] In the following, the black (K) image formed by the ejection head 32K is referred to as a K image, the cyan (C) image formed by the ejection head 32C is referred to as a C image, the magenta (M) image formed by the ejection head 32M is referred to as an M image, and the yellow (Y) image formed by the ejection head 32Y is referred to as a Y image.

[0046] In this embodiment, the ejection heads 32K, 32C, and 32M are examples of the first, second, and third forming means, respectively. Note that any of the ejection heads 32K, 32C, and 32Y, the ejection heads 32K, 32M, and 32Y, and the ejection heads 32C, 32M, and 32Y may be understood as examples of the first, second, and third forming means, respectively.

[0047] Also, the ejection head 32K may be understood as an example of a first forming means, and any one or two of the ejection heads 32C, 32M, and 32Y may be understood as an example of a second forming means. Also, the ejection head 32C may be understood as an example of a first forming means, and any one or two of the ejection heads 32M and 32Y may be understood as an example of a second forming means. Also, the ejection head 32M may be understood as an example of a first forming means, and the ejection head 32Y may be understood as an example of a second forming means.

[0048] (Detection units 40C, 40M, 40Y) 1 are detection units that detect an image formed on the continuous paper P. As an example, the detection units 40C to 40Y are configured with reflective optical sensors.

[0049] 1, the detection units 40C to 40Y have a length equal to or greater than the width of the image area R of the continuous paper P. In other words, the detection ranges of the detection units 40C to 40Y have a length equal to or greater than the width of the image area R of the continuous paper P. Specifically, the detection units 40C to 40Y have a length equal to or greater than the width of the continuous paper P. In other words, the detection ranges of the detection units 40C to 40Y have a length equal to or greater than the width of the continuous paper P. The width of the continuous paper P is the length along the paper width direction.

[0050] In this embodiment, the detection units 40C to 40Y are disposed between the ejection heads 32K to 32Y. Specifically, the detection unit 40C is disposed between the ejection heads 32K and 32C in the transport direction. That is, the detection unit 40C is disposed downstream of the ejection head 32K in the transport direction and upstream of the ejection head 32C in the transport direction. The detection unit 40C may be disposed at a position equidistant to the ejection heads 32K and 32C, or at a position close to one of the ejection heads 32K and 32C.

[0051] The detection unit 40M is disposed between the ejection head 32C and the ejection head 32M in the transport direction. That is, the detection unit 40M is disposed downstream of the ejection head 32C in the transport direction and upstream of the ejection head 32M in the transport direction. The detection unit 40M may be disposed at a position equidistant to the ejection head 32C and the ejection head 32M, or at a position close to one of the ejection head 32C and the ejection head 32M.

[0052] The detection unit 40Y is disposed between the ejection head 32M and the ejection head 32Y in the transport direction. That is, the detection unit 40Y is disposed downstream of the ejection head 32M in the transport direction and upstream of the ejection head 32Y in the transport direction. The detection unit 40Y may be disposed at a position equidistant to the ejection head 32M and the ejection head 32Y, or at a position close to one of the ejection head 32M and the ejection head 32Y.

[0053] The detection units 40C, 40M, and 40Y are an example of the detection means. Specifically, when the ejection head 32C is regarded as an example of the second forming means, the detection unit 40C is regarded as an example of the detection means or the first detection means. Also, when the ejection head 32M is regarded as an example of the second forming means, the detection unit 40M is regarded as an example of the detection means or the first detection means. Also, when the ejection head 32Y is regarded as an example of the second forming means, the detection unit 40Y is regarded as an example of the detection means.

[0054] Furthermore, when the ejection head 32M is regarded as an example of a third forming means, the detection unit 40M is regarded as an example of a second detecting means. When the ejection head 32Y is regarded as an example of a third forming means, the detection unit 40Y is regarded as an example of a second detecting means.

[0055] (Control device 50) Fig. 2 is a block diagram showing a hardware configuration of a control device 50 according to this embodiment. The control device 50 shown in Fig. 2 is a device that controls the operation of each part (e.g., the conveying mechanism 20 and the image forming unit 30, etc.) of the inkjet recording apparatus 10. Specifically, as shown in Fig. 2, the control device 50 has a CPU (Central Processing Unit) 51, a memory 52, a storage 53, a communication interface 54, and an input unit 55. The parts of the control device 50 are connected to each other via a bus 59 so as to be able to communicate with each other.

[0056] The storage 53 stores various programs including a control program and various data including control data. The control program is a program that causes a computer including the CPU 51 to function as the control device 50. Specifically, the storage 53 is realized by a recording device such as an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a flash memory.

[0057] The memory 52 is a working area for the CPU 51 to execute various programs, and temporarily records various programs or various data when the CPU 51 executes processing. The CPU 51 reads various programs including a control program from the storage 53 into the memory 52, and executes the programs using the memory 52 as a working area.

[0058] The communication interface 54 is an interface for communicating with an external device, and transmits and receives various data to and from the external device through communication using various wired or wireless communication lines.

[0059] The input unit 55 is a functional unit where various input operations are performed by the user. Specifically, the input unit 55 is composed of mechanical operation keys such as a keyboard, a touch panel, and the like.

[0060] In the control device 50, the CPU 51 executes a control program to realize various functions for controlling the inkjet recording device 10. The following describes the functional configuration realized by the cooperation of the CPU 51 as a hardware resource and the control program as a software resource. Figure 3 is a block diagram showing the functional configuration of the CPU 51.

[0061] 3, in the control device 50, the CPU 51 executes a control program to function as an acquisition unit 51A, an extraction unit 51B, a detection unit 51C, a control unit 51D, and a reception unit 51E. The extraction unit 51B is an example of an extraction means, the detection unit 51C is an example of a detection means, and the reception unit 51E is an example of a reception means.

[0062] (Acquisition part 51A) The acquiring unit 51A acquires a job execution instruction for executing a job related to image formation and job information related to the job.

[0063] Specifically, the acquisition unit 51A receives a job execution instruction and job information from an external device via the communication interface 54, for example, to acquire the job execution instruction and the job information.

[0064] A job is a processing unit of an image forming operation that is executed in response to a single instruction to execute image formation. Job information includes at least information on whether or not to add a mark for processing (hereinafter referred to as a "processing mark"), and image data.

[0065] The processing mark is a mark used for processing the continuous paper P, and is a predetermined mark. Specifically, the processing mark is a mark of a predetermined shape and size. In this embodiment, the processing mark is a mark (so-called registration mark) that indicates the cutting position of the continuous paper P. In this embodiment, the processing mark is, for example, configured by intersecting a line of a predetermined thickness and length along the transport direction and a line of a predetermined thickness and length along the paper width direction. Furthermore, the processing mark is a mark formed by a K image by the ejection head 32K arranged on the most upstream side.

[0066] It should be noted that, as an example, cutting of the continuous paper P is performed as a post-process in a cutting device separate from the inkjet recording device 10 after an image has been formed. In the cutting device, the processing marks are read by a sensor or the like, and the continuous paper P is cut in accordance with the processing marks. The cut continuous paper P is bound, for example.

[0067] The image data of the processing marks is recorded in the storage 53, and when the acquisition unit 51A acquires information for adding processing marks, the CPU 51 adds the image data of the processing marks to the job information.

[0068] In this way, the image data in the job information includes image data generated by the user and image data previously stored in the control device 50. Note that image data generated by the user may be used as the processing mark.

[0069] Note that a job execution instruction and job information may be generated by reading a document with a reading device (specifically, a scanner), and the job execution instruction and the job information may be acquired by acquisition unit 51A. In addition, acquisition unit 51A may acquire the job execution instruction and the job information by inputting the job execution instruction and the job information through input unit 55.

[0070] (Extraction part 51B) The extraction unit 51B extracts an image for position detection from the image data of the job. Specifically, the extraction unit 51B extracts an image for detection (an example of an image for position detection) to be detected by the detection units 40C, 40M, and 40Y from the image data included in the job information acquired by the acquisition unit 51A.

[0071] When the image data of a job includes a processing mark, the extraction unit 51B extracts the processing mark as a detection image to be detected by the detection units 40C, 40M, and 40Y. In this embodiment, when the image data includes a processing mark, the extraction unit 51B extracts the processing mark preferentially over other images (images other than the processing mark).

[0072] When the image data of a job does not include a processing mark, and the image data of the job includes a K-only image consisting only of a K image, the extraction unit 51B extracts the K-only image as a detection image to be detected by the detection units 40C, 40M, and 40Y.

[0073] The single image is an image that is composed of one color image without forming images of other colors in the predetermined area until it is detected by the most downstream detection unit 40Y. Therefore, the K single image is an image that is composed of only the K image without forming C and M images in the predetermined area until it is detected by the most downstream detection unit 40Y. Since the Y image is formed after being detected by the most downstream detection unit 40Y, the K single image also includes an image composed of two colors, the K image and the Y image, in the predetermined area. In addition, the processing mark can also be considered as a single image. As an example, the predetermined area is an area of ​​10 dots of ink (for example, about 0.4 mm in length) in each of the transport direction and the paper width direction. The predetermined area is not limited to the above area, and may be an area of ​​more than a plurality of dots of ink, and is set according to the detection capabilities of the detection units 40C, 40M, and 40Y.

[0074] Furthermore, when the image data of the job does not include a K single image, the extraction unit 51B extracts a K image (hereinafter referred to as a "K detection image") as a detection image to be detected by the detection unit 40C. The K detection image is an image on which images of other colors (specifically, at least one of a C image and an M image) are superimposed in a predetermined area before it is detected by the detection unit 40Y located on the most downstream side. Note that when the K detection image is detected by the detection unit 40C, it is in a state where it exists alone, since images of other colors have not yet been formed. The K detection image is an example of a first image.

[0075] When the image data of the job does not include a K single image, and when the image data of the job includes a C single image consisting of only a C image, the extraction unit 51B extracts the C single image as a detection image to be detected by the detection units 40M and 40Y. When the image data of the job does not include a C single image, the extraction unit 51B extracts a C image (hereinafter, referred to as a "C detection image") as a detection image to be detected by the detection unit 40M. The C detection image is an image that is superimposed with an image of another color (specifically, at least one of a K image and an M image) in a predetermined region until it is detected by the detection unit 40Y located at the most downstream side. Note that when the C detection image is detected by the detection unit 40M, it is in a state where it is superimposed with the K image or exists alone. The C detection image is an example of a second image.

[0076] When the image data of the job does not include a C single image, and when the image data of the job includes an M single image consisting of only an M image, the extraction unit 51B extracts the M single image as a detection image to be detected by the detection unit 40Y. When the image data of the job does not include an M single image, the extraction unit 51B extracts an M image (hereinafter referred to as an "M detection image") as a detection image to be detected by the detection unit 40Y. The M detection image is an image that is superimposed with an image of another color (specifically, at least one of a K image and a C image) in a predetermined area before being detected by the detection unit 40Y. Note that the M image is superimposed with at least one of a K image and a C image when it is detected by the detection unit 40Y. Hereinafter, the image extracted by the extraction unit 51B as a detection image may be referred to as an extracted image.

[0077] (Detection unit 51C) The detection unit 51C detects the correction amount of each ejection position (an example of an image forming position) of the ejection heads 32C, 32M, and 32Y from the position of the extracted image detected by each of the detection units 40C, 40M, and 40Y and the position of the extracted image in the image data of the job. A specific detection process will be described later.

[0078] (Control unit 51D) The control unit 51D has a function of controlling the driving of each of the ejection heads 32K to 32Y. Specifically, the control unit 51D controls the driving of the ejection head 32K, and performs a process of forming a K image based on image data of a job.

[0079] Furthermore, the control unit 51D controls the driving of each of the ejection heads 32C, 32M, and 32Y based on the correction amount of the ejection position of each of the ejection heads 32C, 32M, and 32Y detected by the detection unit 51C, and performs processing to form each of the C image, M image, and Y image based on the image data of the job. That is, the control unit 51D corrects the ejection positions of the ejection heads 32C, 32M, and 32Y based on the correction amount of the ejection position of each of the ejection heads 32C, 32M, and 32Y detected by the detection unit 51C. Specific image forming processing will be described later. The control unit 51D is an example of a correction means.

[0080] (Reception desk 51E) The reception unit 51E has a function of receiving an instruction to specify a detection image. The reception unit 51E receives an instruction to specify a detection image to be detected by each of the detection units 40C, 40M, and 40Y from an external device via the communication interface 54 by a user, thereby receiving the instruction. When the reception unit 51E receives the instruction, the extraction process by the extraction unit 51B is not performed.

[0081] (Control process of this embodiment) Next, an example of the control process of this embodiment will be described.

[0082] When the CPU 51 receives the job execution instruction and the job information, it reads out the control program from the storage 53 and starts executing the control process.

[0083] 4, when this control process is started, the CPU 51 first executes an extraction process to extract detection images to be detected by the detection units 40C, 40M, and 40Y from the image data of the job (step S101). Next, the CPU 51 executes a K image formation process to form a K image based on the image data of the job (step S102).

[0084] Next, the CPU 51 executes a correction amount detection process to detect a correction amount of the ejection position of the ejection head 32C (step S103). Next, the CPU 51 corrects the ejection position of the ejection head 32C based on the correction amount detected in the correction amount detection process for the ejection head 32C, and executes a C image formation process to form a C image based on the image data of the job (step S104).

[0085] Next, the CPU 51 executes a correction amount detection process to detect a correction amount of the ejection position of the ejection head 32M (step S105). Next, the CPU 51 corrects the ejection position of the ejection head 32M based on the correction amount detected in the correction amount detection process for the ejection head 32M, and executes an M image formation process to form an M image based on the image data of the job (step S106).

[0086] Next, the CPU 51 executes a correction amount detection process to detect a correction amount of the ejection position of the ejection head 32Y (step S107). Next, the CPU 51 corrects the ejection position of the ejection head 32Y based on the correction amount detected in the correction amount detection process for the ejection head 32Y, and executes a Y image formation process to form a Y image based on the image data of the job (step S108).

[0087] The extraction process (step S101) may be performed before the correction amount detection process (step S103) in the ejection head 32C, or may be performed after the K image formation process (step S102). The specific contents of each process will be described below.

[0088] (Extraction process) FIG. 5 is a flowchart showing the flow of the extraction process (step S101 in FIG. 4) executed by the control device 50.

[0089] As shown in FIG. 5, when the CPU 51 starts the execution of the extraction process, it determines whether or not the image data of the job includes a processing mark (step S201).

[0090] As shown in Fig. 6, when the image data of the job includes a processing mark (step S201: YES), the CPU 51 extracts the processing mark as a detection image to be detected by the detection units 40C, 40M, and 40Y (step S202), and ends the extraction process. Note that Fig. 6 and Figs. 7 to 10 described later show a state in which the image data of the job is visualized on the continuous paper P.

[0091] When the image data of the job does not include a processing mark (step S201: NO), the CPU 51 separates the image data into images of each color (step S203) as shown in Fig. 7. In Fig. 7, the K image is composed of characters. Also, in Fig. 7, the C image is represented by vertical lines, the M image is represented by horizontal lines, and the Y image is represented by dots.

[0092] Next, the CPU 51 judges whether or not the image data of the job includes a K single image composed of only a K image (step S204). As shown in Fig. 8, when the image data of the job includes a K single image (step S204: YES), the CPU 51 extracts the K single image as a detection image to be detected by the detection units 40C, 40M, and 40Y (step S205), and ends the extraction process. The K single image is the image surrounded by a two-dot chain line in Fig. 8.

[0093] 9, when the image data of the job does not include a K single image (step S204: NO), the CPU 51 extracts the K detection image as a detection image to be detected by the detection unit 40C (step S206). Note that the image surrounded by the dashed line in FIG. 9 can be used as the K detection image.

[0094] Next, the CPU 51 judges whether or not the image data of the job includes a C single image composed of only a C image (step S207). As shown in Fig. 9, when the image data of the job includes a C single image (step S207: YES), the CPU 51 extracts the C single image as a detection image to be detected by the detection units 40M and 40Y (step S208), and ends the extraction process. The C single image is the image surrounded by a two-dot chain line in Fig. 9.

[0095] As shown in Fig. 10, when the image data of the job does not include a C single image (step S207: NO), the CPU 51 extracts the C detection image as a detection image to be detected by the detection unit 40M (step S209). Note that the image surrounded by the dashed line in Fig. 10 can be used as the C detection image. The image surrounded by the dashed line in Fig. 10 can also be used as the K detection image.

[0096] Next, the CPU 51 judges whether or not the image data of the job includes an M single image composed of only M images (step S210). As shown in Fig. 10, when the image data of the job includes an M single image (step S210: YES), the CPU 51 extracts the M single image as a detection image to be detected by the detection unit 40Y (step S211), and ends the extraction process. Note that the M single image is an image surrounded by a two-dot chain line in Fig. 10.

[0097] When the image data of the job does not include an M single image (step S210: NO), the CPU 51 extracts the M detection image as a detection image to be detected by the detection unit 40Y (step S212), and ends the extraction process.

[0098] In this embodiment, as described above, the CPU 51 judges whether or not the image data of the job includes a processing mark (step S201) before judging whether or not the image data of the job includes other images (for example, a K single image, a C single image, and an M single image) (steps S204, S207, and S210 described later). If the image data of the job includes a processing mark (step S201: YES), the CPU 51 extracts the processing mark as a detection image to be detected by the detection units 40C, 40M, and 40Y (step S202). That is, if the image data of the job includes a processing mark, the CPU 51 extracts the processing mark in preference to other images (for example, a K single image, etc.).

[0099] (K image formation processing) The CPU 51 controls the ejection of the ejection head 32K based on the K image of the image data of the job. As a result, the ejection head 32K ejects black (K) ink droplets onto the continuous paper P to form a K image on the continuous paper P. The K image includes an extracted image extracted by the extraction process. In other words, the ejection head 32K forms an extracted image extracted by the extraction process on the continuous paper P. The K image including the extracted image is detected by the detection unit 40C. The extracted image formed by the ejection head 32K is any one of a processing mark (see step S202), a K single image (see step S205), and a K detection image (see step S206).

[0100] (Correction amount detection process in ejection head 32C) The CPU 51 detects the correction amount of the ejection position of the ejection head 32C from the position of the extracted image detected by the detection unit 40C and the position of the extracted image in the image data of the job. Specifically, the CPU 51 detects the correction amount of the ejection position of the ejection head 32C in the transport direction as follows, for example.

[0101] First, the CPU 51 obtains the reference timing from the position of the extracted image in the image data, as shown in Fig. 11 (step S301). The reference timing is the timing that is the reference for the timing at which the detection unit 40C detects the extracted image. In other words, when the detection unit 40C detects the extracted image at the reference timing, correction of the ejection position of the ejection head 32C in the transport direction is not required (i.e., the correction amount is 0). In other words, the reference timing can be said to be the timing at which the detection unit 40C detects the extracted image when no fluctuation occurs in the transport direction of the continuous paper P.

[0102] Fluctuations in the transport direction of the continuous paper P refer to a state in which the continuous paper P is transported faster or slower, and the timing at which the K image reaches the ejection position of the ejection head 32C is faster or slower. Fluctuations in the transport direction of the continuous paper P occur, for example, due to elongation of the continuous paper P or fluctuations in the tension of the continuous paper P. Elongation of the continuous paper P occurs, for example, when the continuous paper P absorbs ink and swells.

[0103] Next, the CPU 51 determines whether or not the detection timing at which the detection unit 40C actually detects the extracted image matches the reference timing (step S302). If the detection timing matches the reference timing (step S302: YES), the CPU 51 determines that the correction amount is 0 (step S303). That is, the CPU 51 determines that correction is not required.

[0104] If the detection timing does not match the reference timing (step S302: NO), the CPU 51 detects the difference between the detection timing and the reference timing as the correction amount (step S304). Specifically, for example, if the detection timing is delayed from the reference timing, the delay is detected as the correction amount. For example, if the detection timing is earlier than the reference timing, the advance is detected as the correction amount.

[0105] In this way, the CPU 51 detects the correction amount for the ejection timing of the ejection head 32C from the detection timing at which the detection unit 40C actually detects the extracted image and the reference timing.

[0106] The CPU 51 detects the correction amount in the paper width direction, for example, as follows.

[0107] First, the CPU 51 determines a reference position in the paper width direction from the position of the extracted image in the image data (step S401). The reference position is a reference position in the paper width direction at which the detection unit 40C detects the extracted image. In other words, when the detection unit 40C detects the extracted image at the reference position, correction of the ejection position of the ejection head 32C in the paper width direction is not required (i.e., the correction amount is 0). In other words, the reference position can be said to be the detection position at which the detection unit 40C detects the extracted image when no fluctuation occurs in the paper width direction of the continuous paper P.

[0108] Incidentally, the fluctuation in the paper width direction of the continuous paper P refers to a state in which the continuous paper P is shifted to one side in the paper width direction. The fluctuation in the paper width direction of the continuous paper P occurs, for example, when the continuous paper P meanders.

[0109] Next, the CPU 51 determines whether or not the detection position where the detection unit 40C actually detects the extracted image matches the reference position (step S402). If the detection position matches the reference position (step S402: YES), the CPU 51 detects the correction amount as 0 (step S403). That is, the CPU 51 determines that correction is not required.

[0110] When the detected position does not match the reference position (step S402: NO), the CPU 51 detects the difference between the detected position and the reference position as the correction amount (step S404). Specifically, for example, when the detected position is shifted to one side in the paper width direction from the reference position, the CPU 51 detects the shift amount as the correction amount.

[0111] (C Image formation processing) The CPU 51 controls the driving of the ejection head 32C based on the correction amount of the ejection position of the ejection head 32C detected by the correction amount detection process, and performs processing to form a C image based on the image data of the job.

[0112] Specifically, the CPU 51 controls the ejection timing of the ejection head 32C based on the correction amount of the ejection timing of the ejection head 32C detected by the correction amount detection process. Also, the CPU 51 shifts the ejection position of the ejection head 32C in the paper width direction by changing the nozzles that eject ink droplets based on the correction amount of the ejection position of the ejection head 32C detected by the correction amount detection process. This causes the ejection head 32C to eject cyan (C) ink droplets onto the continuous paper P to form a C image on the continuous paper P. In this way, the CPU 51 corrects the ejection position of the ejection head 32C based on the correction amount of the ejection position of the ejection head 32C detected by the correction amount detection process.

[0113] Note that the ejection position of the ejection head 32C may be shifted in the paper width direction by moving the ejection head 32C itself in the paper width direction.

[0114] In the extraction process, if a C single image (see step S208) or a C detection image (see step S209) is extracted, the C image formed on the continuous paper P includes the C single image or C detection image as an extracted image. That is, in this case, the ejection head 32C forms the extracted image extracted by the extraction process on the continuous paper P. The C image including this extracted image is detected by the detection unit 40M.

[0115] In the extraction process, when the processing mark (see step S202) or the K single image (see step S205) is extracted as the detection image, the C single image (see step S208) and the C detection image (see step S209) are not extracted as the detection image. In this case, the processing mark (see step S202) or the K single image (see step S205) is detected by the detection unit 40M.

[0116] In this embodiment, the image forming process based on the correction amount is executed on the page on which the detection image is formed on the continuous paper P. The image forming process based on the correction amount may be executed on the page following the page on which the detection image is formed on the continuous paper P.

[0117] (Correction amount detection process in ejection head 32M) The CPU 51 detects the correction amount of the ejection position of the ejection head 32M from the position of the extracted image detected by the detection unit 40M and the position of the extracted image in the image data of the job. Specifically, the CPU 51 detects the correction amount of the ejection position of the ejection head 32M in the transport direction, similar to the correction amount detection process for the ejection head 32C described above (see FIG. 11).

[0118] Furthermore, the CPU 51 detects the amount of correction of the ejection position of the ejection head 32M in the paper width direction, similar to the correction amount detection process for the ejection head 32C described above (see FIG. 12).

[0119] (M image formation processing) The CPU 51 controls the driving of the ejection head 32M based on the correction amount of the ejection position of the ejection head 32M detected by the correction amount detection process, and performs processing to form an M image based on the image data of the job.

[0120] Specifically, the CPU 51 controls the ejection timing of the ejection head 32M based on the correction amount of the ejection timing of the ejection head 32M detected by the correction amount detection process. Also, the CPU 51 shifts the ejection position of the ejection head 32M in the paper width direction by changing the nozzle that ejects ink droplets based on the correction amount of the ejection position of the ejection head 32M detected by the correction amount detection process. This causes the ejection head 32M to eject magenta (M) ink droplets onto the continuous paper P to form an M image on the continuous paper P. In this way, the CPU 51 corrects the ejection position of the ejection head 32M based on the correction amount of the ejection position of the ejection head 32M detected by the correction amount detection process.

[0121] Note that the ejection position of the ejection head 32M may be shifted in the paper width direction by moving the ejection head 32M itself in the paper width direction.

[0122] In the extraction process, when an M single image (see step S211) or an M detection image (see step S212) is extracted, the M image formed on the continuous paper P includes the M single image or M detection image as an extracted image. That is, in this case, the ejection head 32M forms the extracted image extracted by the extraction process on the continuous paper P. The M image including this extracted image is detected by the detection unit 40Y.

[0123] In the extraction process, if any of the processing mark (see step S202), the K single image (see step S205), and the C single image (see step S208) is extracted as a detection image, the M single image (see step S211) and the M detection image (see step S212) are not extracted as detection images. In this case, the detection unit 40Y detects any of the processing mark (see step S202), the K single image (see step S205), and the C single image (see step S208).

[0124] In this embodiment, the image forming process based on the correction amount is executed on the page on which the detection image is formed on the continuous paper P. The image forming process based on the correction amount may be executed on the page following the page on which the detection image is formed on the continuous paper P.

[0125] (Correction amount detection process for ejection head 32Y) The CPU 51 detects the correction amount of the ejection position of the ejection head 32Y from the position of the extracted image detected by the detection unit 40Y and the position of the extracted image in the image data of the job. Specifically, the CPU 51 detects the correction amount of the ejection position of the ejection head 32Y in the transport direction, similar to the correction amount detection process for the ejection head 32C described above (see FIG. 11).

[0126] Furthermore, the CPU 51 detects the amount of correction for the ejection position of the ejection head 32Y in the paper width direction, similar to the correction amount detection process for the ejection head 32C described above (see FIG. 12).

[0127] (Y image formation process) The CPU 51 controls the driving of the ejection head 32Y based on the correction amount of the ejection position of the ejection head 32Y detected by the correction amount detection process, and performs processing to form a Y image based on the image data of the job.

[0128] Specifically, the CPU 51 controls the ejection timing of the ejection head 32Y based on the correction amount of the ejection timing of the ejection head 32Y detected by the correction amount detection process. Also, the CPU 51 shifts the ejection position of the ejection head 32Y in the paper width direction by changing the nozzles that eject ink droplets based on the correction amount of the ejection position of the ejection head 32Y detected by the correction amount detection process. This causes the ejection head 32Y to eject yellow (Y) ink droplets onto the continuous paper P to form a Y image on the continuous paper P. In this way, the CPU 51 corrects the ejection position of the ejection head 32Y based on the correction amount of the ejection position of the ejection head 32Y detected by the correction amount detection process.

[0129] In this embodiment, the image forming process based on the correction amount is executed on the page on which the detection image is formed on the continuous paper P. The image forming process based on the correction amount may be executed on the page following the page on which the detection image is formed on the continuous paper P.

[0130] Moreover, the ejection position of the ejection head 32Y may be shifted in the paper width direction by moving the ejection head 32Y itself in the paper width direction.

[0131] (Action according to this embodiment) Next, the operation of this embodiment will be described.

[0132] According to this embodiment, a detection image is extracted from the image data of a job, and the detection result of the extracted image is used to detect the correction amount of each of the ejection positions of the ejection heads 32C, 32M, and 32Y. In other words, in this embodiment, the correction amount of each of the ejection positions of the ejection heads 32C, 32M, and 32Y is detected using an image formed in the image area R of the continuous paper P based on the image data of the job in response to an instruction to execute the job.

[0133] Here, in a configuration in which a mark dedicated for detection is formed on the continuous paper P (hereinafter referred to as a first configuration), the correction amount for the ejection position of each of the ejection heads 32C, 32M, and 32Y is detected using the detection result of the mark dedicated for detection formed on the continuous paper P. In the first configuration, as shown in Fig. 13, it is necessary to provide an area N1 in which the mark dedicated for detection M1 is formed separately from the image area R, and therefore the image area R becomes narrower by the amount of the area N1.

[0134] In contrast, in this embodiment, as described above, the correction amount for each ejection position of the ejection heads 32C, 32M, and 32Y is detected using an image formed in the image area R of the continuous paper P based on the image data of the job upon instruction to execute the job, thereby increasing the image area R available to the user.

[0135] In this embodiment, when the processing mark (see step S202) or the K single image (see step S205) formed by the discharge of the discharge head 32K is extracted as the detection image, each of the detection units 40C, 40M, and 40Y detects the extracted image. Then, the correction amount of the discharge position of each of the discharge heads 32C, 32M, and 32Y is detected from the position of the extracted image detected by each of the detection units 40C, 40M, and 40Y and the position of the extracted image in the image data of the job (steps S103, S105, and S107). Therefore, the images formed by each of the discharge heads 32C, 32M, and 32Y are aligned with the image formed by the discharge head 32K.

[0136] 5, in this embodiment, when a K single image is included in the job image data (step S204: YES), the K single image is extracted as a detection image to be detected by the detection units 40C, 40M, and 40Y (step S205). Then, the amount of correction for the ejection position of each of the ejection heads 32C, 32M, and 32Y is detected from the position of the extracted image detected by each of the detection units 40C, 40M, and 40Y and the position of the extracted image in the job image data (steps S103, S105, and S107).

[0137] Here, in a configuration (hereinafter referred to as a second configuration) in which an image in which the K image by the ejection head 32K and the C image by the ejection head 32C are superimposed is extracted as a detection image, if the ejection positions of the ejection heads 32K and 32C are misaligned, the superimposed images in a misaligned state will be detected. This may cause a detection error in the correction amount of the ejection positions of the ejection heads 32M and 32Y.

[0138] In contrast, when extracting a K-only image as a detection image to be detected by detection units 40C, 40M, and 40Y, an image formed by ejection head 32K alone is used, so that detection errors in the correction amount are suppressed compared to the second configuration.

[0139] In this embodiment, if the job image data does not include a K single image (step S204: NO), the K detection image is extracted as a detection image to be detected by the detection unit 40C (step S206). Then, the correction amount of the ejection position of the ejection head 32C is detected from the position of the extracted image detected by the detection unit 40C and the position of the extracted image in the job image data (step S103). Furthermore, the C single image (step S208) or the C detection image (step S209) is extracted, and the correction amount of the ejection position of the ejection head 32M is detected from the position of the extracted image detected by the detection unit 40M and the position of the extracted image in the job image data (step S105).

[0140] In this case, the C image formed by the ejection head 32C is aligned with the K image formed by the ejection head 32K, and the M image formed by the ejection head 32M is aligned with the C image formed by the ejection head 32C.

[0141] In this embodiment, when the image data of the job includes a processing mark (step S201: YES), the processing mark is extracted as a detection image to be detected by the detection units 40C, 40M, and 40Y (step S202). The processing mark is a mark used in processing the continuous paper P, and is a predetermined mark. In this embodiment, the processing mark is a default mark recorded in the storage 53.

[0142] Therefore, the process of extracting the detection image is simpler than in a configuration in which only an image other than the processing mark (for example, an image designated by the user) is extracted as the detection image.

[0143] In addition, in this embodiment, when the image data of the job includes a processing mark, the CPU 51 extracts the processing mark with priority over other images (for example, a K-only image, etc.). This simplifies the extraction process of the detection image compared to a configuration in which other images are extracted with priority.

[0144] (Modification of Extraction Process) In this embodiment, when the image data of a job includes a K single image (step S204: YES), the CPU 51 extracts the K single image as a detection image to be detected by the detection units 40C, 40M, and 40Y (step S205), but this is not limited to the above. For example, the CPU 51 may extract the K detection image as a detection image to be detected by the detection unit 40C (step S206) without determining whether the image data of a job includes a K single image (step S204). That is, the CPU 51 may extract the K detection image as a detection image to be detected by the detection unit 40C regardless of whether the image data of a job includes a K single image.

[0145] Similarly, when the image data of the job includes a C single image (step S207: YES), the CPU 51 extracts the C single image as a detection image to be detected by the detection units 40M and 40Y (step S208), but this is not limited to the above. For example, the CPU 51 may extract the C detection image as a detection image to be detected by the detection unit 40M (step S209) without determining whether the image data of the job includes a C single image (step S207). In other words, the CPU 51 may extract the C detection image as a detection image to be detected by the detection unit 40M regardless of whether the image data of the job includes a C single image.

[0146] Furthermore, when the image data of the job contains an M single image (step S210: YES), the CPU 51 similarly extracts the M single image as a detection image to be detected by the detection unit 40Y (step S211), but this is not limited thereto. For example, the CPU 51 may extract the M detection image as a detection image to be detected by the detection unit 40Y (step S212) without determining whether the image data of the job contains an M single image (step S210). That is, the CPU 51 may extract the M detection image as a detection image to be detected by the detection unit 40Y regardless of whether the image data of the job contains an M single image.

[0147] In the present embodiment, the control device 50 includes a reception unit 51E that receives an instruction to specify an image for detection, thereby enabling the user to specify an image for detection.

[0148] In this embodiment, the detection units 40C to 40Y have a length equal to or greater than the width of the image area R of the continuous paper P. Therefore, no matter where the detection image is formed in the width direction of the image area R, the detection image can be detected.

[0149] More specifically, the detection units 40C to 40Y have a length equal to or greater than the width of the continuous paper P. Therefore, even if the detection image is formed on the continuous paper P so as to extend beyond the image area R, the detection image can be detected.

[0150] (Modification of the correction amount detection process for the ejection heads 32C, 32M, and 32Y) Although the correction amount of each ejection position of the ejection heads 32C, 32M, and 32Y is detected from the position of the extracted image detected by each of the detection units 40C, 40M, and 40Y and the position of the extracted image in the image data of the job, this is not limited to this. For example, the correction amount of each ejection position of the ejection heads 32C, 32M, and 32Y may be detected from the shape of the extracted image detected by each of the detection units 40C, 40M, and 40Y and the shape of the extracted image in the image data of the job.

[0151] Specifically, a characteristic portion (a portion having a characteristic shape) of a K image (e.g., a K single image) in the image data of a job may be extracted, and the correction amount of each ejection position of the ejection heads 32C, 32M, and 32Y may be detected based on the shape of the extracted image. An example of the characteristic portion is a portion formed in a ring shape (e.g., the portion surrounded by a two-dot chain line in FIG. 14).

[0152] Also, for example, two images spaced apart in the paper width direction (for example, the portion surrounded by the dashed line in FIG. 14) may be extracted as detection images. In this case, the amount of correction for the skew (inclination) of each of the ejection heads 32C, 32M, and 32Y may be detected from the positions of the two extracted images detected by each of the detection units 40C, 40M, and 40Y and the positions of the two extracted images in the image data of the job.

[0153] In this way, it is sufficient to detect the amount of correction for the ejection positions of the ejection heads 32C, 32M, and 32Y from the extracted image, and various methods, including known methods, can be used to detect the amount of correction.

[0154] Second Embodiment Next, an inkjet recording apparatus 200 according to a second embodiment will be described. Fig. 15 is a schematic diagram showing the configuration of an inkjet recording apparatus 200 according to a second embodiment. Note that parts configured in the same manner as in the first embodiment are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0155] In the first embodiment, the detection units 40C, 40M, and 40Y are disposed between the ejection heads 32K to 32Y, but in this embodiment, a single detection unit 240 is disposed downstream in the transport direction relative to the ejection head 32Y disposed at the most downstream side in the transport direction. The detection unit 240 is an example of a detection means.

[0156] In this embodiment, the extraction unit 51B extracts each of the K image, C image, M image, and Y image as a detection image to be detected by the detection unit 240. As the K image, for example, any of the above-mentioned processing mark, K single image, and K detection image is extracted. As the C image, M image, and Y image, for example, each of the C single image, M single image, and Y single image is extracted.

[0157] The detection unit 51C detects the amount obtained by subtracting "the amount of deviation between the position of the C image detected by the detection unit 240 and the position of the C image in the image data of the job in the transport direction and the paper width direction" from "the amount of deviation between the position of the K image detected by the detection unit 240 and the position of the K image in the image data of the job in the transport direction and the paper width direction" as the correction amount of the ejection position of the ejection head 32C. In other words, the detection unit 51C detects the amount obtained by subtracting "the difference between the position of the K image and the position of the C image on the image detected by the detection unit 240" from "the difference between the position of the K image and the position of the C image on the image data" as the correction amount of the ejection position of the ejection head 32C.

[0158] Similarly, the detection unit 51C detects the amount obtained by subtracting the “difference between the position of the C image and the position of the M image on the image detected by the detection unit 240” from the “difference between the position of the C image and the position of the M image on the image data” as the correction amount for the ejection position of the ejection head 32M.

[0159] Furthermore, the detection unit 51C similarly detects the amount obtained by subtracting the "difference between the position of the M image and the position of the Y image on the image detected by the detection unit 240" from the "difference between the position of the M image and the position of the Y image on the image data" as the correction amount for the ejection position of the ejection head 32M.

[0160] Then, the control unit 51D controls the driving of each of the ejection heads 32C, 32M, and 32Y based on the correction amount of the ejection position of each of the ejection heads 32C, 32M, and 32Y detected by the detection unit 51C, and performs processing to form each of the C image, M image, and Y image based on the image data of the job. Note that, in this embodiment, the image formation processing based on the correction amount is performed on the page next to the page on which the detection image was formed and thereafter.

[0161] In this embodiment, the detection unit 240 is disposed downstream in the transport direction relative to the ejection head 32Y disposed at the most downstream side in the transport direction, so there is a high degree of freedom in the arrangement of the detection unit compared to a configuration in which the detection unit is disposed between each of the ejection heads 32K to 32Y. Also, in this embodiment, since it is configured with a single detection unit 240, it is possible to reduce the number of parts, reduce costs, and simplify the configuration.

[0162] (Modification) In the first and second embodiments, the inkjet recording apparatuses 10 and 200 are used as an example of the image forming apparatus, but the present invention is not limited to this. For example, the image forming apparatus may be an electrophotographic type image forming apparatus that forms a toner image on the continuous paper P through the processes of charging, exposing, developing, transferring, and fixing.

[0163] The present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements are possible without departing from the spirit and scope of the present invention. For example, the above-described modified examples may be appropriately combined to form a configuration.

[0164] In addition, in the above embodiment, the processor refers to a processor in a broad sense, and includes a general-purpose processor (e.g., the aforementioned CPU, etc.) and a dedicated processor (e.g., GPU: Graphics Processing Unit, ASIC: Application Specific Integrated Circuit, FPGA: Field Programmable Gate Array, programmable logic device, etc.).

[0165] In addition, the operations of the processor in the above embodiment may be performed not only by one processor but also by multiple processors located at physically separate locations working together. The order of the operations of the processor is not limited to the order described in the above embodiment, and may be changed as appropriate. [Explanation of symbols]

[0166] 10, 200 Inkjet recording device (an example of an image forming device) 32K Discharge head (an example of a first forming means) 32C Discharge head (an example of a second forming means) 32M Discharge head (an example of a third forming means) 40C Detection unit (an example of a detection means, an example of a first detection means) 40M Detection unit (an example of a second detection means) 51B Extraction unit (an example of an extraction means) 51C Detection unit (an example of a detection means) 51E Reception unit (an example of a reception means) 240 Detection unit (an example of detection means) P Continuous paper (an example of a recording medium)

Claims

1. An extraction means for extracting an image for position detection from image data of a job; a first image forming means for forming an image for position detection on a recording medium; a detection means for detecting the image for position detection formed by the first image forming means; a detection means for detecting a correction amount of an image forming position of a second image forming means disposed downstream in a conveying direction of the recording medium with respect to the first image forming means, based on a position of an image for position detection detected by the detection means and a position of the image for position detection in the image data; having The extraction means extracts a processing mark indicating a cutting position of the continuous paper as the recording medium as an image for position detection. Image forming device.

2. When the image data includes a mark for processing, the extraction means extracts the mark for processing preferentially over other images. The image forming apparatus according to claim 1 .

3. the detection unit is a first detection unit disposed downstream in the transport direction with respect to the first image forming unit and upstream in the transport direction with respect to the second image forming unit, a second detection unit that detects the image for position detection formed by the first image forming unit is disposed downstream of the second image forming unit in the transport direction; The detection unit detects a correction amount of a formation position of a third image forming unit downstream of the second detection unit in the transport direction from a position of the image for position detection detected by the second detection unit and a position of the image for position detection in the image data.

3. The image forming apparatus according to claim 1 or 2.

4. The extraction means extracts a single image formed only by the image formed by the first image forming means as the image for position detection. The image forming apparatus according to claim 3 .

5. When the image data of the job does not include the single image, the extraction unit A first image formed by one image forming means and a second image formed by the second image forming means are extracted as images for position detection; The detection means detects a correction amount of the formation position of the second image forming means from the position of the first image detected by the first detection means and the position of the first image in the image data, and detects a correction amount of the formation position of the third image forming means from the position of the second image detected by the second detection means and the position of the second image in the image data. The image forming apparatus according to claim 4 .

6. the detection unit is disposed downstream of the second image forming unit in the transport direction, the extraction means extracts a first image formed by the first image forming means and a second image formed by the second image forming means as images for position detection; The detection means detects a correction amount of the formation position of the second image forming means from a difference between a position of a first image detected by the detection means and a position of the first image in the image data, and a difference between a position of a second image detected by the detection means and a position of the second image in the image data. The image forming apparatus according to any one of claims 1 to 5.

7. The detection means has a length equal to or greater than the width of the image area of ​​the recording medium. The image forming apparatus according to any one of claims 1 to 6.

8. The detection means has a length equal to or greater than the width of the recording medium. The image forming apparatus according to claim 7.

9. A receiving unit is provided for receiving an instruction to specify an image for position detection. The image forming apparatus according to any one of claims 1 to 8.

10. An extraction means for extracting, when image data of a job includes a single image consisting of an image of one color, the single image from the image data as an image for position detection; a first image forming means for forming an image for position detection on a recording medium; a detection means for detecting the image for position detection formed by the first image forming means; The position of the image for position detection detected by the detection means and the position detection in the image data From the position of the image to be conveyed, the downstream side of the conveying direction of the recording medium with respect to the first image forming means a detection means for detecting a correction amount of an image forming position of a second image forming means disposed on the first image forming means; have Image forming device.

11. An image forming apparatus as described in any one of claims 1 to 10, further comprising a correction means for correcting the image formation position based on the correction amount detected by the detection means.

Images