Printer, printing control method, and printing control program

Abstract

To enable accurate specification of a position of a discharge failure nozzle in an ink jet printer equipped with a meandering correction function.SOLUTION: In an ink jet printer equipped with a meandering correction function, a layout processing unit 450 that generates print image data by determining a printing position of each image on each of a plurality of pages to be printed shifts the printing positions of all images in the paper width direction based on the meandering amount of the print paper with the printing position when there is no meandering of the print paper as a reference for normal pages, and shifts the printing position of a cue mark in the paper width direction based on the meandering amount of the print paper with the printing position when there is no meandering of the print paper as a reference while maintaining the printing position of a discharge failure detection pattern image at the printing position when there is no meandering of the print paper for a nozzle check page.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a printing device (i.e., an inkjet type continuous sheet printing device) that prints by ejecting ink onto a long length of printing medium, and more specifically, to a technology that accurately identifies the position of a nozzle that is in a defective ejection state (hereinafter referred to as a "faulty ejection nozzle") even if the printing medium meanders. [Background technology]

[0002] Inkjet printing devices that perform printing by discharging ink onto a printing medium such as printing paper are widely known. In an inkjet printing device, when the discharge interval becomes long, during the period when printing is being performed, the ink may dry due to evaporation of the solvent near the nozzle, air bubbles may get mixed into the nozzle, and dust may adhere to the nozzle. In other words, nozzle discharge failure may occur. When discharge failure occurs, defects in the printed image such as white streaks and missing dots occur. Therefore, conventionally, operations (cleaning and flushing) for recovering the function of the discharge failure nozzle and substitute droplet ejection in which ink droplets that should be ejected by the discharge failure nozzle are ejected by a surrounding nozzle are performed. Note that discharge failure nozzles are detected, for example, by visual inspection by an operator or numerical analysis by an inspection device based on a printed image of a predetermined pattern image (hereinafter referred to as a "discharge failure detection pattern image") as a test chart.

[0003] Furthermore, in inkjet printing devices, the print medium may meander when it is transported by a transport mechanism. When the print medium meanders, misregistration (for example, misregistration between the front and back sides or misregistration between multiple colors) occurs, resulting in reduced print quality. Therefore, a technique has been proposed that corrects input image data so that the printing position of an image shifts according to the amount of meandering of the print medium. Such a technique is disclosed, for example, in JP 2016-55570 A. In the following, the function of correcting input image data according to the amount of meandering of the print medium so as to suppress the occurrence of misregistration is referred to as a "meandering correction function." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-55570 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, in an inkjet printing device having a meandering correction function, a process of shifting the printing position of an image according to the meandering amount of the printing medium during printing (hereinafter referred to as a "printing position shift process") is performed on all pages. Therefore, when a plurality of pages to be printed include a normal page composed of an image based on submitted data and a nozzle check page composed of the above-mentioned ejection failure detection pattern image, the printing position shift process is performed on not only the normal page but also the nozzle check page. Therefore, even if a nozzle with a defective ejection is detected based on the printed image of the ejection failure detection pattern image included in the nozzle check page, the exact position of the nozzle with a defective ejection cannot be specified. Therefore, for example, the presence or absence of a nozzle with a defective ejection is determined on a head (ink ejection head) basis. However, it is strongly desired to be able to accurately specify the position of the nozzle with a defective ejection while suppressing the occurrence of misregistration caused by the meandering of the printing medium.

[0006] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to make it possible to accurately identify the position of a nozzle having ejection problems in an inkjet printing device having a meandering correction function. [Means for solving the problem]

[0007] A first aspect of the present invention is a printing device that performs printing by ejecting ink onto a print medium that is elongated in a transport direction, a transport mechanism that transports the print medium in a first direction; at least one ink ejection head including a plurality of nozzles arranged in a second direction perpendicular to the first direction, and ejecting ink from the plurality of nozzles onto the print medium being transported by the transport mechanism; at least one edge detection sensor that detects the position of an edge of the print medium being transported by the transport mechanism; a meander amount calculation unit that calculates the amount of meandering of the print medium based on the position of the edge detected by the at least one edge detection sensor; a mark image detection sensor for detecting a mark image to be placed at a predetermined position on the printing medium; a layout processing unit that generates print image data by determining a print position of each image on each of a plurality of pages to be printed, taking the meandering amount into consideration, based on input image data including a plurality of images; an ink ejection control unit that controls the ejection of ink from the at least one ink ejection head based on the print image data; Equipped with the plurality of pages are configured by a nozzle check page including a pattern image for detecting a discharge failure and the mark image for detecting a nozzle in a discharge failure state from among the plurality of nozzles, and a normal page including an image other than the pattern image for detecting a discharge failure and the mark image, The layout processing unit is characterized in that, for the normal page, the printing positions of all images are shifted in the second direction based on the meandering amount, with the printing position when the meandering amount is 0 as a reference, and, for the nozzle check page, the layout processing unit shifts the printing position of the mark image in the second direction based on the meandering amount, with the printing position when the meandering amount is 0 as a reference, while maintaining the printing position of the pattern image for detecting ejection defects at the printing position when the meandering amount is 0.

[0008] The second invention is the first invention, the nozzle check page further includes a pattern image for position identification for identifying the position of a nozzle having a discharge defect detected based on the pattern image for detecting a discharge defect, The layout processing unit maintains the printing position of the pattern image for position identification at the printing position when the amount of meandering is zero.

[0009] The third invention is the first invention, the nozzle check page includes an accessory image; The layout processing unit is characterized in that it shifts the printing position of the accessory image included in the nozzle check page in the second direction based on the amount of meandering, with the printing position when the amount of meandering is 0 as a reference.

[0010] The fourth invention relates to the first invention, When the printing medium meanders and causes the printing position of at least a portion of the pattern image for detecting ejection defects to fall outside the area of ​​the printing medium, the layout processing unit performs a trimming process to remove the portion of the pattern image for detecting ejection defects whose printing position falls outside the area of ​​the printing medium.

[0011] The fifth invention relates to the fourth invention, When the printing position of at least a portion of the pattern image for detecting ejection defects falls outside the area of ​​the printing medium due to the meandering of the printing medium, the layout processing unit expands the printing area of ​​the pattern image for detecting ejection defects by a width equivalent to the amount of meandering in the direction in which the printing medium is shifted.

[0012] The sixth aspect of the present invention relates to the first aspect of the present invention, the at least one ink ejection head includes a plurality of ink ejection heads respectively corresponding to a plurality of ink colors; the at least one edge detection sensor includes a plurality of edge detection sensors respectively corresponding to the plurality of ink ejection heads; the meandering amount calculation unit calculates the meandering amount for each of the plurality of ink colors; The layout processing unit determines the print position of each image for each ink color, taking into consideration the corresponding meandering amount.

[0013] The seventh aspect of the present invention is any one of the first to sixth aspects of the present invention, The printing apparatus further includes an imaging device that captures the ejection failure detection pattern image recorded on the printing medium.

[0014] The eighth aspect of the present invention relates to the seventh aspect of the present invention, The printing device includes: a discharge failure position specifying unit that specifies the position of a nozzle having a discharge failure based on the discharge failure detection pattern image captured by the imaging device; an ink amount compensation processing unit that corrects the printing image data so as to compensate for the amount of ink ejected onto the printing medium, based on the position of the nozzle in an ejection failure state identified by the ejection failure position identifying unit; The present invention is characterized by further comprising:

[0015] A ninth aspect of the present invention is a print control method for a printing device that performs printing by ejecting ink onto a print medium having a long shape in a transport direction, comprising: The printing device includes: a transport mechanism that transports the print medium in a first direction; at least one ink ejection head including a plurality of nozzles arranged in a second direction perpendicular to the first direction, and ejecting ink from the plurality of nozzles onto the print medium being transported by the transport mechanism; at least one edge detection sensor that detects the position of an edge of the print medium being transported by the transport mechanism; a mark image detection sensor for detecting a mark image to be placed at a predetermined position on the printing medium; Equipped with The printing control method includes: a meander amount calculation step of calculating a meander amount of the print medium based on the position of the edge detected by the at least one edge detection sensor; a layout processing step for generating print image data by determining the print position of each image on each of a plurality of pages to be printed, taking the meandering amount into consideration, based on input image data including a plurality of images; an ink ejection control step of controlling the ejection of ink from the at least one ink ejection head based on the print image data; Including, the plurality of pages are configured by a nozzle check page including a pattern image for detecting a discharge failure and the mark image for detecting a nozzle in a discharge failure state from among the plurality of nozzles, and a normal page including an image other than the pattern image for detecting a discharge failure and the mark image, In the layout processing step, for the normal page, the printing positions of all images are shifted in the second direction based on the meandering amount, with the printing position when the meandering amount is 0 as a reference, and for the nozzle check page, the printing position of the pattern image for detecting ejection defects is maintained at the printing position when the meandering amount is 0, and the printing position of the mark image is shifted in the second direction based on the meandering amount, with the printing position when the meandering amount is 0 as a reference.

[0016] A tenth aspect of the present invention is a print control program for controlling an operation of a printing device that performs printing by ejecting ink onto a print medium that is elongated in a transport direction, the program comprising: a computer included in the printing device, the computer including: a transport mechanism that transports the print medium in a first direction; at least one ink ejection head that includes a plurality of nozzles arranged in a second direction perpendicular to the first direction and ejects ink from the plurality of nozzles onto the print medium being transported by the transport mechanism; at least one edge detection sensor that detects the position of an edge of the print medium being transported by the transport mechanism; and a mark image detection sensor that detects a mark image to be placed at a predetermined position on the print medium; a meander amount calculation step of calculating a meander amount of the print medium based on the position of the edge detected by the at least one edge detection sensor; a layout processing step for generating print image data by determining the print position of each image on each of a plurality of pages to be printed, taking the meandering amount into consideration, based on input image data including a plurality of images; an ink ejection control step of controlling the ejection of ink from the at least one ink ejection head based on the print image data; Run the command, the plurality of pages are configured by a nozzle check page including a pattern image for detecting a discharge failure and the mark image for detecting a nozzle in a discharge failure state from among the plurality of nozzles, and a normal page including an image other than the pattern image for detecting a discharge failure and the mark image, In the layout processing step, for the normal page, the printing positions of all images are shifted in the second direction based on the meandering amount, with the printing position when the meandering amount is 0 as a reference, and for the nozzle check page, the printing position of the pattern image for detecting ejection defects is maintained at the printing position when the meandering amount is 0, and the printing position of the mark image is shifted in the second direction based on the meandering amount, with the printing position when the meandering amount is 0 as a reference. Effect of the Invention

[0017] According to the first aspect of the present invention, the printing device is provided with a layout processing unit that generates image data for printing by determining the printing position of each image on each of a plurality of pages to be printed in consideration of the meandering amount of the printing medium. The layout processing unit shifts the printing positions of all images for normal pages in a second direction (a direction perpendicular to the conveying direction of the printing medium) based on the meandering amount of the printing medium, but shifts the printing position of the mark image in the second direction based on the meandering amount of the printing medium without shifting the printing position of the pattern image for detecting discharge failure for a nozzle check page used to detect a nozzle in a discharge failure state (discharge failure nozzle). As a result, even if the printing medium meanders, the positional relationship between the pattern image for detecting discharge failure and the nozzle is maintained, and the positional relationship between the printing medium and the mark image is also maintained. Therefore, it is possible to accurately identify the position of the discharge failure nozzle by inspection based on the printed image of the pattern image for detecting discharge failure. In addition, there is no misalignment between the front and back sides, and no error occurs when the mark image is detected by the mark image detection sensor. As described above, it is possible to accurately identify the position of the discharge failure nozzle in a printing device having a meandering correction function.

[0018] According to the second aspect of the present invention, even if the printing medium meanders, the positional relationship between the position identifying pattern image and the nozzles is maintained, which makes it possible to more accurately identify the position of the nozzle that is not ejecting ink in a printing device that has a meandering correction function.

[0019] According to the third aspect of the present invention, even if the print medium meanders, it is possible to maintain the positional relationship between the print medium and the accessory image included in the nozzle check page.

[0020] According to the fourth aspect, the ink is prevented from being ejected outside the area of ​​the print medium.

[0021] According to the fifth aspect of the present invention, it is possible to prevent the range of nozzles for inspecting the ink ejection state from being narrowed due to meandering of the print medium.

[0022] According to the sixth aspect of the present invention, the printing position of each image is adjusted for each ink color, so that the occurrence of misregistration (misregistration) among a plurality of colors is effectively suppressed.

[0023] According to the seventh aspect of the present invention, it is possible to accurately identify the position of the discharge-failure nozzle based on the captured image obtained by the imaging device capturing the discharge-failure detection pattern image.

[0024] According to the eighth aspect of the present invention, the position of the ejection-failed nozzle is accurately identified, and a process is performed to compensate for the amount of ink ejected onto the printing medium based on that position. This allows the ejection of the ink that should have been ejected from the ejection-failed nozzle to be compensated for with high accuracy. As a result, the occurrence of defects in the printed image when an ejection-failed nozzle is present is effectively suppressed.

[0025] According to the ninth aspect of the invention, the same effects as those of the first aspect of the invention can be obtained.

[0026] According to the tenth aspect of the present invention, the same effects as those of the first aspect of the present invention can be obtained. [Brief description of the drawings]

[0027] [Figure 1] 1 is a diagram illustrating the overall configuration of a printing system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing a schematic configuration of an inkjet printing apparatus in the embodiment. [Diagram 3] FIG. 2 is a schematic diagram showing a configuration example of a printing mechanism in the embodiment. [Figure 4] FIG. 2 is a schematic plan view of a main part of a printing mechanism in the embodiment as viewed from above. [Diagram 5] FIG. 4 is a plan view showing one configuration example of a recording unit in the embodiment. [Figure 6] 5 is a diagram for explaining an example of an arrangement of nozzles in an ink ejection head in the embodiment. FIG. [Figure 7] FIG. 2 is a block diagram showing a hardware configuration of the print control device in the embodiment. [Figure 8] 3 is a block diagram showing a functional configuration of a control unit realized by execution of a print control program in the print control device in the embodiment. FIG. [Figure 9] 5A to 5C are schematic diagrams illustrating an example of a pattern image for detecting ejection defects in the embodiment. [Figure 10] 13 is a diagram showing a layout obtained when the position of the left edge of the printing paper coincides with the reference position. FIG. [Figure 11] 13 is a diagram showing the correspondence between the printing paper and the nozzles when the position of the left edge of the printing paper coincides with a reference position. FIG. [Figure 12] FIG. 1 is a diagram for explaining a conventional layout process. [Figure 13] FIG. 1 is a diagram for explaining a conventional layout process. [Figure 14] 13A and 13B are diagrams for explaining layout processing in a hypothetical case in which print position shift processing is not performed only on the nozzle check page. [Figure 15] 13A and 13B are diagrams for explaining layout processing in a hypothetical case in which print position shift processing is not performed only on the nozzle check page. [Figure 16] FIG. 11 is a diagram for explaining a layout process in the embodiment. [Figure 17] FIG. 11 is a diagram for explaining a layout process in the embodiment. [Figure 18] FIG. 11 is a diagram for explaining a layout process in the embodiment. [Figure 19] FIG. 11 is a diagram for explaining a layout process in the embodiment. [Figure 20] 10 is a flowchart showing a procedure of a process related to a meandering correction function in the embodiment. [Figure 21] FIG. 11 is a diagram for explaining the effects of the above embodiment. [Figure 22] FIG. 11 is a diagram for explaining the effects of the above embodiment. [Figure 23] 13 is a schematic diagram showing the configuration of a test chart used to detect ejection-fault nozzles in a first modified example of the embodiment. FIG. [Figure 24] FIG. 11 is a diagram for explaining an effect of the first modified example. [Diagram 25] FIG. 11 is a diagram for explaining an effect of the first modified example. [Figure 26] FIG. 11 is a diagram for explaining that an end detection sensor is provided for each ink color in a second modified example of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. It is assumed that the pages to be printed are made up of a nozzle check page and a normal page.

[0029] <1. Overall configuration of the printing system> FIG. 1 is a diagram showing the overall configuration of a printing system according to an embodiment of the present invention. This printing system is composed of an inkjet printing device 10 and a print data generating device 30. The inkjet printing device 10 and the print data generating device 30 are connected to each other via a LAN 4. The print data generating device 30 generates image data for printing by performing a rasterization process on input data such as a PDF file. This image data is data that has not been subjected to halftone processing, and halftone processing is performed by a print control device 100 in the inkjet printing device 10 as described later. The image data generated by the print data generating device 30 is transmitted to the inkjet printing device 10 via the LAN 4. Note that printing information that specifies the position of an image on each page is also transmitted from the print data generating device 30 to the inkjet printing device 10. The inkjet printing device 10 is composed of a printing machine main body 200 and a print control device 100 that controls the operation of the printing machine main body 200. The inkjet printing device 10 outputs a print image on a printing paper as a printing medium based on image data transmitted from the print data generating device 30 without using a printing plate. The present invention can also be applied to the case where a printing medium other than printing paper (for example, film) is used.

[0030] <2. Configuration of the printer body of the inkjet printing device> FIG. 2 is a diagram showing a schematic configuration of the inkjet printing device 10. As described above, the inkjet printing device 10 is composed of a printing machine main body 200 and a printing control device 100. The printing machine main body 200 includes a paper delivery section 21 that supplies printing paper (in this example, rolled printing paper) 5 having a long shape in the transport direction, a printing mechanism 22a for front side printing, a reversing unit 24 that reverses the front side and back side of the printing paper 5, a printing mechanism 22b for back side printing, and a paper winding section 23 that winds up the printing paper 5 after printing into a roll. The printing mechanism 22a for front side printing and the printing mechanism 22b for back side printing have the same configuration. Hereinafter, when there is no need to distinguish between the printing mechanism 22a for front side printing and the printing mechanism 22b for back side printing, the printing mechanisms are given the reference numeral 22.

[0031] 3 is a schematic diagram showing an example of the configuration of the printing mechanism 22. The printing mechanism 22 includes a first drive roller 221 for transporting the printing paper 5 to the inside, a plurality of support rollers 222 for transporting the printing paper 5 inside the printing mechanism 22, a recording unit 223 for recording a print image on the printing paper 5, a drying mechanism 224 for drying the printing paper 5 on which the print image has been recorded, and a second drive roller 225 for outputting the printing paper 5 from inside the printing mechanism 22. The paper delivery unit 21 (see FIG. 2), the first drive roller 221, the plurality of support rollers 222, the second drive roller 225, and the paper winding unit 23 (see FIG. 2) realize a transport mechanism for transporting the printing paper 5 in a predetermined transport direction. The recording unit 223 is composed of a K head unit 223k that ejects K (black) ink, a C head unit 223c that ejects C (cyan) ink, an M head unit 223m that ejects M (magenta) ink, and a Y head unit 223y that ejects Y (yellow) ink. In the following, when there is no need to distinguish between the K head unit 223k, the C head unit 223c, the M head unit 223m, and the Y head unit 223y, the head units are given the symbol 223. The printing mechanism 22 also includes an edge detection sensor 61 that detects the position of one edge (hereinafter referred to as the "edge position") in the paper width direction (direction perpendicular to the transport direction of the printing paper 5) of the printing paper 5 transported by the transport mechanism, a cue mark detection sensor 62 that detects a cue mark that indicates the start position of the image printing area corresponding to each page, and an in-line scanner 63 as an imaging device that captures the print image. The imaging data obtained by the in-line scanner 63 capturing the print image is sent to the print control device 100.

[0032] 3 is merely an example and is not intended to be limiting. For example, the cue mark detection sensor 62 may not be provided in the printing mechanism 22a for front side printing, and may be provided only in the printing mechanism 22b for back side printing.

[0033] FIG. 4 is a schematic plan view of the main part of the printing mechanism 22 as seen from above. The printing paper 5 is continuously transported from the bottom to the top in FIG. 4. In the process of transporting the printing paper 5, the edge detection sensor 61 detects the above-mentioned edge position. Next, for example, when printing is performed on the printing paper 5 on which only the cue mark 52 has already been printed, or when printing is resumed after the printing paper 5 is rewound due to a printing interruption caused after the printing of the cue mark 52, the cue mark detection sensor 62 detects the cue mark 52. Then, the recording unit 223 records the image in the image printing area 51. Note that, for example, when the cue mark 52 has not yet been recorded on the printing paper 5, the cue mark 52 is also recorded on the printing paper 5. The printing paper 5 on which the print image has been recorded passes through the drying mechanism 224. This causes the printing paper 5 to dry. Then, the in-line scanner 63 captures the print image.

[0034] FIG. 5 is a plan view showing an example of the configuration of the recording unit 223. As shown in FIG. 5, the recording unit 223 is composed of a K-color head unit 223k, a C-color head unit 223c, an M-color head unit 223m, and a Y-color head unit 223y, which are arranged in a row in the transport direction of the print paper 5. Each head unit 223 is composed of a plurality of ink ejection heads (print heads) 251 arranged in a staggered pattern. Each ink ejection head 251 includes a large number of nozzles (not shown in FIG. 5) that eject ink. Each nozzle of the ink ejection head 251 included in the K-color head unit 223k ejects K-color ink, each nozzle of the ink ejection head 251 included in the C-color head unit 223c ejects C-color ink, each nozzle of the ink ejection head 251 included in the M-color head unit 223m ejects M-color ink, and each nozzle of the ink ejection head 251 included in the Y-color head unit 223y ejects Y-color ink.

[0035] FIG. 6 is a diagram for explaining an example of the arrangement of nozzles in the ink ejection head 251. Typically, the ink ejection head 251 includes a plurality of rows of nozzle groups each consisting of a plurality of nozzles arranged in a line in the paper width direction. In the example shown in FIG. 6, the ink ejection head 251 includes four rows of nozzle groups. The portion marked with the reference numeral 41 in FIG. 6 shows a schematic diagram of the landing position of the ink ejected from each nozzle on the printing paper 5. The nozzles in the ink ejection head 251 are arranged so that the landing position of the ink ejected from the nozzles included in the first row of nozzle groups, the landing position of the ink ejected from the nozzles included in the second row of nozzle groups, the landing position of the ink ejected from the nozzles included in the third row of nozzle groups, and the landing position of the ink ejected from the nozzles included in the fourth row of nozzle groups are different from each other. For example, the landing position of the ink ejected from each nozzle included in the first row of nozzle groups is a position between the landing position of the ink ejected from the nozzles included in the third row of nozzle groups and the landing position of the ink ejected from the nozzles included in the fourth row of nozzle groups. 6, the landing position 42 of the ink ejected from the nozzle labeled 252(p) is a position between the landing position 43 of the ink ejected from the nozzle labeled 252(q) and the landing position 44 of the ink ejected from the nozzle labeled 252(r). Note that the transport direction of the printing paper 5 corresponds to the first direction, and the paper width direction corresponds to the second direction.

[0036] <3. Hardware configuration of print control device> FIG. 7 is a block diagram showing a hardware configuration of the print control device 100. As shown in FIG. 7, the print control device 100 includes a main body 110, an auxiliary storage device 121, an optical disk drive 122, a display unit 123, a keyboard 124, and a mouse 125. The main body 110 includes a CPU 111, a memory 112, a first disk interface unit 113, a second disk interface unit 114, a display control unit 115, an input interface unit 116, and a communication interface unit 117. The CPU 111, the memory 112, the first disk interface unit 113, the second disk interface unit 114, the display control unit 115, the input interface unit 116, and the communication interface unit 117 are connected to each other via a system bus. The auxiliary storage device 121 is connected to the first disk interface unit 113. The optical disk drive 122 is connected to the second disk interface unit 114. The display unit (display device) 123 is connected to the display control unit 115. A keyboard 124 and a mouse 125 are connected to the input interface unit 116. The printing machine main body 200 is connected to the communication interface unit 117 via a communication cable. The communication interface unit 117 is also connected to the LAN 4. The auxiliary storage device 121 is a magnetic disk device or the like. An optical disk 19 serving as a computer-readable recording medium such as a CD-ROM or DVD-ROM is inserted into the optical disk drive 122. The display unit 123 is a liquid crystal display or the like. The display unit 123 is used to display information desired by the operator. The keyboard 124 and the mouse 125 are used by the operator to input instructions to this print control device 100.

[0037] The auxiliary storage device 121 stores a print control program (program for controlling the execution of print processing by the printer body 200) 13. The CPU 111 reads the print control program 13 stored in the auxiliary storage device 121 into the memory 112 and executes it to realize various functions of the print control device 100. The memory 112 includes a RAM (Random Access Memory) and a ROM (Read Only Memory). The memory 112 functions as a work area for the CPU 111 to execute the print control program 13 stored in the auxiliary storage device 121. The print control program 13 is stored in the computer-readable recording medium (non-transient recording medium) and provided. That is, the user, for example, purchases an optical disk 19 as a recording medium for the print control program 13, inserts it into the optical disk drive 122, reads out the print control program 13 from the optical disk 19, and installs it in the auxiliary storage device 121.

[0038] <4. Functional configuration of the control unit> 8 is a block diagram showing the functional configuration of the control unit 400 realized by executing the print control program 13 in the print control device 100. The control unit 400 includes a transport control unit 410, a meandering amount calculation unit 420, an accessory generation circuit 430, an image data receiving unit 441, a print information receiving unit 442, a layout processing unit 450, a data conversion unit 460, a drying control unit 470, an imaging control unit 480, and an inspection unit 490. The layout processing unit 450 includes a print position shift processing unit 452. The data conversion unit 460 includes an ink amount compensation processing unit 462.

[0039] The conveyance control unit 410 controls the speed (conveyance speed) at which the conveyance mechanism 29 conveys the print paper 5. The drying control unit 470 controls the temperature (drying temperature) at which the drying mechanism 224 dries the print paper 5 after printing. The imaging control unit 480 controls the timing of capturing an image of a print image by the inline scanner 63. The inspection unit 490 inspects for the presence or absence of a faulty discharge nozzle and (if there is a faulty discharge nozzle) identifies the position of the faulty discharge nozzle based on a captured image obtained by the inline scanner 63 capturing a printed image of a pattern image for detecting faulty discharge included in the nozzle check page.

[0040] The meander amount calculation unit 420 calculates the meander amount of the printing paper 5 (the amount of deviation from the original position of the printing paper 5) based on the edge position detected by the edge detection sensor 61. For example, if the printing paper 5 deviates to the right in the transport direction, the meander amount value will be a positive value, and if the printing paper 5 deviates to the left in the transport direction, the meander amount value will be a negative value. The accessory generation circuit 430 generates accessory images (for example, registration marks, cut marks, barcodes) to be placed in an area outside the page on the printing paper 5.

[0041] The image data receiving unit 441 receives image data transmitted from the print data generating device 30. The print information receiving unit 442 receives print information transmitted from the print data generating device 30. The print information includes information that specifies the layout position of each image (image based on image data) on each page, information that specifies the layout position of each accessory image on each page, information for identifying whether the page to be processed is a normal page or a nozzle check page (or information indicating whether the print position shift process is performed on the page to be processed), and the like. The pattern image for detecting discharge defects is held in, for example, the auxiliary storage device 121 so that it can be referenced by the layout processing unit 450. However, like the image data, the pattern image for detecting discharge defects may also be transmitted from the print data generating device 30 and received by the image data receiving unit 441.

[0042] The layout processing unit 450 determines the printing position of each image (image included in the image data received by the image data receiving unit 441, accessory image generated by the accessory generating circuit 430, and pattern image for detecting discharge defects) on each of the multiple pages to be printed, taking into consideration the meandering amount calculated by the meandering amount calculation unit 420 (hereinafter referred to as the "calculated meandering amount") while referring to the printing information received by the printing information receiving unit 442. In this way, the image data for printing is generated. At this time, the printing position shift processing unit 452 applies printing position shift processing to the normal page, but does not apply printing position shift processing to the nozzle check page. However, with respect to the nozzle check page, the printing position of the cue mark 52 is shifted in the paper width direction based on the calculated meandering amount. Also, if an accessory image is included in the nozzle check page, the printing position of the accessory image is shifted in the paper width direction based on the calculated meandering amount.

[0043] As described above, for normal pages, the layout processing unit 450 shifts the printing positions of all images in the paper width direction based on the calculated meandering amount using the printing positions when the meandering amount of the printing paper 5 is 0 as a reference, and for nozzle check pages, while maintaining the printing positions of the discharge defect detection pattern images at the printing positions when the meandering amount of the printing paper 5 is 0, the layout processing unit shifts the printing positions of the cue marks 52 in the paper width direction based on the calculated meandering amount using the printing positions when the meandering amount of the printing paper 5 is 0 as a reference. In addition, the layout processing unit shifts the printing positions of accessory images included in the nozzle check page in the paper width direction based on the calculated meandering amount using the printing positions when the meandering amount of the printing paper 5 is 0 as a reference.

[0044] When the meandering of the printing paper 5 causes the printing position of at least a part of the pattern image for detecting discharge defects to be outside the region of the printing paper 5, the layout processing unit 450 performs a trimming process to remove the part of the pattern image for detecting discharge defects whose printing position is outside the region of the printing paper 5, and expands the printing region of the pattern image for detecting discharge defects by a width equivalent to the calculated meandering amount in the direction in which the printing paper 5 is shifted. By performing the trimming process in this manner, the ejection of ink outside the region of the printing paper 5 is prevented. Furthermore, by expanding the printing region of the pattern image for detecting discharge defects by a width equivalent to the calculated meandering amount, the range of nozzles for inspecting the ink ejection state is prevented from being narrowed due to the meandering of the printing paper 5.

[0045] The data conversion unit 460 generates halftone image data including information indicating the dot size of the ink corresponding to each pixel by performing halftone processing on the print image data generated by the layout processing unit 450, triggered by the detection of the cue mark 52 by the cue mark detection sensor 62. At that time, if the position of the nozzle with the ejection failure is identified by the inspection unit 490, the ink amount compensation processing unit 462 performs ink amount compensation processing to correct the print image data so that the amount of ink ejected onto the print paper 5 is compensated before the print image data is subjected to the halftone processing. Note that the specific method of the halftone processing is not particularly limited, and known methods such as the error diffusion method and the dither method can be adopted. The halftone image data generated by the data conversion unit 460 is provided to the recording unit 223. As a result, ink is ejected from each nozzle included in each ink ejection head 251 constituting the recording unit 223 based on the halftone image data.

[0046] In this embodiment, the cue mark detection sensor 62 realizes a mark image detection sensor, the data conversion unit 460 realizes an ink discharge control unit, and the inspection unit 490 realizes a discharge defect position specifying unit.

[0047] <5. Pattern image for detecting discharge defects> 9 is a schematic diagram showing an example of a pattern image 71 for detecting discharge failures as a test chart included in a nozzle check page. The pattern image 71 for detecting discharge failures is composed of a plurality of linear patterns 711, which are regular stepped patterns. Each linear pattern 711 is a pattern formed by ink being discharged from a corresponding nozzle. Note that in reality, the pattern image 71 for detecting discharge failures is composed of more linear patterns 711 than those shown in FIG. 9. For example, if one head unit includes 24,000 nozzles, the pattern image 71 for detecting discharge failures for one color is composed of 24,000 linear patterns 711.

[0048] <6. Layout processing> Next, with reference to Figs. 10 to 19, we will explain how the layout processing unit 450 performs the layout processing (processing for determining the print position of each image on each of the multiple pages to be printed). With reference to Figs. 10 to 19, the nozzle check page is given the reference number 7NC, the normal page that is the page before the nozzle check page is given the reference number 7J1, and the normal page that is the page after the nozzle check page is given the reference number 7J2. Also, the reference number 75 is given to the thick dotted line that indicates the original position (hereinafter referred to as the "reference position") as the position of the left edge of the printing paper 5. Here, it is assumed that when the position of the left edge of the printing paper 5 coincides with the reference position 75 (i.e., when the amount of meandering of the printing paper 5 is 0), a layout such as that shown in Fig. 10 is obtained. Furthermore, as shown in FIG. 11, it is assumed that nozzles are present not only in the range corresponding to the paper width of the printing paper 5 (the range indicated by the arrow with reference symbol 76) when the position of the left edge of the printing paper 5 coincides with the reference position 75, but also in the left part of the printing paper 5 (the part indicated by the arrow with reference symbol 77) and the right part of the printing paper 5 (the part indicated by the arrow with reference symbol 78).

[0049] First, the conventional layout process will be described. According to the conventional layout process, the above-mentioned print position shift process is performed on both the normal pages 7J1 and 7J2 and the nozzle check page 7NC. When the position of the left edge of the printing paper 5 is shifted to the left of the reference position 75, for example, a layout as shown in FIG. 12 is obtained. As can be seen from FIG. 10 and FIG. 12, for both the normal pages 7J1 and 7J2 and the nozzle check page 7NC, the distance from the left edge of the printing paper 5 to the cue mark 52 and the distance from the left edge of the printing paper 5 to the image printing area 51 do not change whether the position of the left edge of the printing paper 5 coincides with the reference position 75 or the position of the left edge of the printing paper 5 is shifted to the left of the reference position 75. When the position of the left edge of the printing paper 5 is shifted to the right of the reference position 75, for example, a layout as shown in FIG. 13 is obtained. 10 and 13, for both normal pages 7J1 and 7J2 and nozzle check page 7NC, the distance from the left edge of the printing paper 5 to the cue mark 52 and the distance from the left edge of the printing paper 5 to the image printing area 51 do not change when the position of the left edge of the printing paper 5 coincides with the reference position 75 and when the position of the left edge of the printing paper 5 is shifted to the right of the reference position 75. According to the conventional layout processing as described above, different nozzles are used to print an image when the position of the left edge of the printing paper 5 coincides with the reference position 75 and when the position of the left edge of the printing paper 5 is shifted from the reference position 75. Therefore, the exact position of the nozzle with the ejection failure cannot be identified based on the printed image of the nozzle check page 7NC.

[0050] Next, a hypothetical case will be described in which the print position shift process is not performed only on the nozzle check page 7NC in the conventional layout process. In this case, when the position of the left edge of the printing paper 5 is shifted to the left of the reference position 75, for example, a layout as shown in FIG. 14 is obtained. As can be understood from FIG. 10 and FIG. 14, for the normal pages 7J1 and 7J2, the distance from the left edge of the printing paper 5 to the cue mark 52 and the distance from the left edge of the printing paper 5 to the image printing area 51 do not change when the position of the left edge of the printing paper 5 coincides with the reference position 75 and when the position of the left edge of the printing paper 5 is shifted to the left of the reference position 75. For the nozzle check page 7NC, the distance from the left edge of the printing paper 5 to the cue mark 52 and the distance from the left edge of the printing paper 5 to the image printing area 51 differ when the position of the left edge of the printing paper 5 coincides with the reference position 75 and when the position of the left edge of the printing paper 5 is shifted to the left of the reference position 75. In this case, when the position of the left edge of the printing paper 5 is shifted to the right of the reference position 75, for example, a layout as shown in FIG. 15 is obtained. As can be seen from FIG. 10 and FIG. 15, for the normal pages 7J1 and 7J2, the distance from the left edge of the printing paper 5 to the cue mark 52 and the distance from the left edge of the printing paper 5 to the image printing area 51 do not change when the position of the left edge of the printing paper 5 coincides with the reference position 75 and when the position of the left edge of the printing paper 5 is shifted to the right of the reference position 75. For the nozzle check page 7NC, an image portion (a shaded portion with a reference symbol 81 in FIG. 15) that cannot be printed is generated because the printing position is outside the area of ​​the printing paper 5. According to the processing of this case, depending on the meandering state of the printing paper 5, the range of nozzles in which ejection defects can be detected by the nozzle check page 7NC may be narrower than it should be. In addition, the distance from the left edge of the printing paper 5 to the cue mark 52 in the nozzle check page 7NC will be different when the position of the left edge of the printing paper 5 coincides with the reference position 75 from when the position of the left edge of the printing paper 5 deviates from the reference position 75, which may result in misalignment between the front and back sides or an error when reading the cue mark 52 with the cue mark detection sensor 62.

[0051] Next, the layout process in this embodiment will be described. In this embodiment, when the position of the left edge of the printing paper 5 is shifted to the left of the reference position 75, for example, a layout as shown in FIG. 16 is obtained. For the normal pages 7J1 and 7J2, the process is the same as the conventional layout process (see FIG. 12). For the nozzle check page 7NC, the print position shift process is not performed as described above, so first, a layout as shown in part A of FIG. 17 is obtained. Then, the print position of the cue mark 52 is shifted in the direction in which the printing paper 5 is shifted by a distance equivalent to the meander amount calculated by the meander amount calculation unit 420. As a result, a layout as shown in part B of FIG. 17 is obtained. When the position of the left edge of the printing paper 5 is shifted to the right of the reference position 75, for example, a layout as shown in FIG. 18 is obtained. For the normal pages 7J1 and 7J2, the process is the same as the conventional layout process (see FIG. 13). For the nozzle check page 7NC, the print position shift process is not performed, so first, a layout similar to a hypothetical case in which the print position shift process is not performed only on the nozzle check page 7NC in the conventional layout process is obtained. That is, a layout as shown in part A of FIG. 19 is obtained. The shaded portion with the reference numeral 84 is an image portion that cannot be printed because the printing position is outside the area of ​​the printing paper 5. After the layout as shown in part A of FIG. 19 is obtained, the printing position of the cue mark 52 is shifted by a distance corresponding to the meandering amount calculated by the meandering amount calculation unit 420 in the direction in which the printing paper 5 is shifted. As a result, the distance from the left end of the printing paper 5 to the cue mark 52 becomes the same as when the position of the left end of the printing paper 5 coincides with the reference position 75. Furthermore, the image printing area 51 in which the discharge failure detection pattern image is printed is expanded by a distance (width) corresponding to the meandering amount calculated by the meandering amount calculation unit 420 in the direction in which the printing paper 5 is shifted. In this manner, a layout as shown in part B of FIG. 19 is obtained. The area with the reference numeral 83 in part B of FIG. 18 and FIG. 19 is an area of ​​the image printing area 51 expanded in accordance with the meandering of the printing paper 5. It should be noted that the area indicated by reference numeral 82 in part B of FIGS. 18 and 19 is an area to be removed by the trimming process.

[0052] As described above, according to the layout process of this embodiment, the distance from the left edge of the printing paper 5 to the cue mark 52 in the nozzle check page 7NC does not change whether the position of the left edge of the printing paper 5 coincides with the reference position 75 or the left edge of the printing paper 5 deviates from the reference position 75. Therefore, no positional deviation occurs between the front and back sides, and no error occurs when the cue mark 52 is read by the cue mark detection sensor 62. In addition, each image (each linear pattern with reference numeral 711 in FIG. 9) constituting the pattern image for detecting discharge failures is formed by ejecting ink from the same nozzle when the position of the left edge of the printing paper 5 coincides with the reference position 75 or the left edge of the printing paper 5 deviates from the reference position 75. Therefore, when a discharge failure nozzle exists, the position of the discharge failure nozzle can be accurately identified based on the printed image of the pattern image for detecting discharge failures.

[0053] <7. Processing Procedure> The procedure of the process related to the meandering correction function will be described with reference to the flowchart shown in Fig. 20. Note that in this embodiment, processing is performed for a plurality of pages including a normal page and a nozzle check page.

[0054] First, the meander amount calculation unit 420 calculates the meander amount of the printing paper 5 based on the edge position (the position of the edge of the printing paper 5) detected by the edge detection sensor 61 (step S10). Next, the control unit 400 judges whether or not all data (image data, print information, etc.) required for processing the page to be processed has been obtained (step S20). As a result, if all data required for processing has been obtained, the process proceeds to step S30, and if any data required for processing has not yet been obtained, the process returns to step S10.

[0055] In step S30, the layout processing unit 450 determines whether the page to be processed is a target for the print position shift process (step S30). As a result, if the page to be processed is a target for the print position shift process, the process proceeds to step S31, and if the page to be processed is not a target for the print position shift process, the process proceeds to step S32. Specifically, normal pages are a target for the print position shift process, but nozzle check pages are not a target for the print position shift process.

[0056] In step S31, layout processing including print position shift processing is performed on the page to be processed by the layout processing unit 450. More specifically, when generating the print image data, the print positions of all images in the normal page in the image data received by the image data receiving unit 441 are shifted according to the meandering amount calculated in step S10.

[0057] In step S32, the layout processing unit 450 performs layout processing on the page to be processed, taking into account the meandering amount, without performing print position shift processing. More specifically, when generating the print image data, the print position of the pattern image for discharge failure detection in the nozzle check page is maintained, and the print position of the cue mark 52 in the nozzle check page is shifted according to the meandering amount calculated in step S10. As described above, if the print paper 5 meanders and the print position of at least a part of the pattern image for discharge failure detection falls outside the area of ​​the print paper 5, the part of the pattern image for discharge failure detection whose print position falls outside the area of ​​the print paper 5 is removed by trimming processing, and the print area of ​​the pattern image for discharge failure detection is expanded by a width equivalent to the meandering amount calculated in step S10 in the direction in which the print paper 5 is shifted.

[0058] In step S40, the data conversion unit 460 performs halftone processing on the print image data generated in step S31 or step S32 for the page to be processed. The halftone image data obtained thereby is then transferred to the recording unit 223. As a result, ink is ejected from each nozzle included in each ink ejection head 251 constituting the recording unit 223 based on the halftone image data.

[0059] In step S50, the control unit 400 determines whether or not the processing for all pages has been completed. As a result, if there is a page for which the processing has not been completed, the process returns to step S10, and if the processing for all pages has been completed, the entire processing related to the meandering correction function ends.

[0060] In this embodiment, step S10 realizes a meander amount calculation step, steps S30 to S32 realize a layout processing step, and step S40 realizes an ink ejection control step.

[0061] <8. Effects> The inkjet printing device 10 according to this embodiment is provided with a layout processing unit 450 that generates print image data by determining the printing position of each image on each of a plurality of pages to be printed, taking into consideration the meandering amount of the printing paper 5. For the nozzle check page, the layout processing unit 450 maintains the printing position of the discharge defect detection pattern image at the printing position when the meandering amount of the printing paper 5 is zero, while shifting the printing position of the cue mark 52 in the paper width direction based on the printing position when the meandering amount of the printing paper 5 is zero, based on the calculated meandering amount described above.

[0062] Here, for example, when the position of the left edge of the printing paper 5 coincides with the reference position 75, it is assumed that the cue mark 52 and the pattern image 71 for detecting discharge failure are laid out as shown in FIG. 21 for the nozzle check page 7NC. The nozzles within the dotted line marked with the reference symbol 86 in FIG. 21 are the nozzles corresponding to the image printing area 51 in which the pattern image 71 for detecting discharge failure is printed. Under the above premise, it is assumed that the position of the left edge of the printing paper 5 shifts to the right of the reference position 75 due to the meandering of the printing paper 5. In this case, the layout as shown in FIG. 22 is obtained for the nozzle check page 7NC. The nozzles used to print the pattern image 71 for detecting discharge failure are the same in the layout shown in FIG. 21 and the layout shown in FIG. 22. That is, even if the printing paper 5 meanders, the positional relationship between the pattern image 71 for detecting discharge failure and the nozzles is maintained. For this reason, it is possible to accurately identify the position of the discharge-failed nozzle by inspection based on the printed image of the pattern image 71 for detecting discharge failure. 21 and 22, the distance from the left edge of the printing paper 5 to the cue mark 52 is the same. Therefore, there is no misalignment between the front and back sides, and no error occurs when the cue mark detection sensor 62 reads the cue mark 52.

[0063] As described above, according to this embodiment, in the inkjet printing device 10 having a meandering correction function, it is possible to accurately identify the position of the nozzle with a discharge defect. In addition, since the position of the nozzle with a discharge defect can be accurately identified, the resources required to deal with the nozzle with a discharge defect can be reduced compared to the conventional method. In this way, it is also possible to contribute to the achievement of the SDGs (Sustainable Development Goals). Furthermore, a process is performed to compensate for the amount of ink discharged onto the printing paper 5 based on the accurately identified position of the nozzle with a discharge defect. This effectively suppresses the occurrence of defects in the printed image when a nozzle with a discharge defect is present.

[0064] <9. Variations> Below, a modification of the above embodiment will be described.

[0065] <9.1 First modified example> In the above embodiment, the test chart for detecting discharge-failure nozzles was composed only of the discharge-failure detection pattern image 71, which is an image of a regular stepped pattern as shown in Fig. 9. However, the present invention is not limited to this. In this modified example, the test chart for detecting discharge-failure nozzles is composed of the discharge-failure detection pattern image 71 and a position identification pattern image for detecting the position of the discharge-failure nozzle.

[0066] Fig. 23 is a schematic diagram showing the configuration of a test chart 7 used to detect ejection-failure nozzles in this modified example. As shown in Fig. 23, the test chart 7 in this modified example is composed of an ejection failure detection pattern image 71 in which a large number of linear patterns are regularly arranged in a stepped pattern, and a position specification pattern image 79 made up of a plurality of linear patterns aligned in the paper width direction. For convenience, in Fig. 23, the stepped regular patterns that constitute the ejection failure detection pattern image 71 are represented by a large number of oblique lines aligned in the paper width direction.

[0067] The test chart 7 is configured so that the discharge failure detection pattern image 71 and the position identification pattern image 79 correspond to each other in position in the paper width direction. The image on one end side of the discharge failure detection pattern image 71 and the image on one end side of the position identification pattern image 79 match in position in the paper width direction, and the image on the other end side of the discharge failure detection pattern image 71 and the image on the other end side of the position identification pattern image 79 match in position in the paper width direction. The multiple linear patterns constituting the position identification pattern image 79 are patterns extending in the transport direction of the printing paper 5 and are arranged at equal intervals in the paper width direction. In addition, the interval between adjacent linear patterns in the position identification pattern image 79 is a predetermined interval. Each of these multiple linear patterns is associated with one specific nozzle and is a pattern of one dot width recorded on the printing paper 5 only by ink ejected from the corresponding nozzle.

[0068] As shown in FIG. 23, the plurality of linear patterns constituting the pattern image 79 for position specification are grouped into a plurality of linear pattern groups (seven linear pattern groups in the example shown in FIG. 23), with three linear patterns of the same length adjacent to each other being one group. Each set of linear pattern groups constitutes a position mark indicating a position in the paper width direction on the test chart 7. In FIG. 23, the same reference numerals are given to position marks including linear patterns of the same length. As shown in FIG. 23, the pattern image 79 for position specification includes one or more position mark pairs each including two position marks each including a linear pattern group of the same length, and one position mark including a linear pattern group (three linear patterns) having a length different from that of any of the linear pattern groups in the one or more position mark pairs. In this regard, the one or more position mark pairs are symmetrically arranged in the paper width direction with the one position mark as the center. Therefore, the one position mark is arranged in the center, and each position mark pair is arranged so as to sandwich the one position mark. In the example shown in FIG. 23, three position mark pairs (PM1, PM1), (PM2, PM2), and (PM3, PM3) are arranged symmetrically with one position mark PM4 at the center.

[0069] The position marks in the pattern image 79 for position identification are classified into several types according to the length of the linear pattern group included in each of the position marks. The length of the linear pattern group included in each type of position mark is predetermined. Therefore, the type of each position mark in the pattern image 79 for position identification can be determined by the length of the linear pattern group included in the position mark. In FIG. 23, the position mark consisting of the shortest linear pattern group is given the symbol PM1, the position mark consisting of the second shortest linear pattern group is given the symbol PM2, the position mark consisting of the second shortest linear pattern group is given the symbol PM3, and the position mark consisting of the longest linear pattern group is given the symbol PM4. In the example shown in FIG. 23, three position mark pairs (PM1, PM1), (PM2, PM2), and (PM3, PM3) are arranged so that the length of the linear pattern becomes shorter as it moves away from the central position mark PM4.

[0070] As described above, the pattern image 79 for position identification included in the test chart 7 in this modified example includes a plurality of position marks each consisting of a linear pattern of the same length arranged at a predetermined interval. This allows the position marks to be correctly detected even if a linear pattern that should not actually exist is included in the printed image of the test chart 7 due to dust or the like. Also, each linear pattern in each position mark is associated with one specific nozzle. Therefore, a position to be used as a reference in the printed image of the test chart 7 can be obtained from any of the linear patterns in the detected position marks, and the position of the defective discharge nozzle can be identified based on the position and the inspection result of the printed image of the pattern image 71 for detecting defective discharge.

[0071] In this modified example, the layout processing unit 450 does not shift the printing position of the discharge failure detection pattern image 71 included in the test chart 7 or the position identification pattern image 79 included in the test chart 7 during the layout process (step S32 in FIG. 20). For example, when the position of the left edge of the printing paper 5 coincides with the reference position 75, it is assumed that the cue mark 52, the position identification pattern image 79, and the discharge failure detection pattern image 71 are laid out as shown in FIG. 24 for the nozzle check page 7NC. The nozzles within the dotted line marked with the reference symbol 87 in FIG. 24 are nozzles corresponding to the image printing area 51 in which the discharge failure detection pattern image 71 is printed. Under the above premise, it is assumed that the left edge of the printing paper 5 is shifted to the right of the reference position 75 due to the meandering of the printing paper 5. At this time, a layout as shown in FIG. 25 is obtained for the nozzle check page 7NC. The nozzles used to print the pattern image 79 for position identification and the pattern image 71 for discharge failure detection are the same in the layout shown in FIG. 24 and the layout shown in FIG. 25. That is, even if the printing paper 5 meanders, the positional relationship between the pattern image 79 for position identification and the nozzles and the positional relationship between the pattern image 71 for discharge failure detection and the nozzles are maintained. Therefore, even if a line pattern that should not actually exist is included in the printed image of the test chart 7 due to dust or the like, the position of the discharge-faulty nozzle can be accurately identified by an inspection based on the printed image of the pattern image 71 for discharge failure detection. In addition, the distance from the left end of the printing paper 5 to the cue mark 52 is the same in the layout shown in FIG. 24 and the layout shown in FIG. 25. Therefore, as in the above embodiment, there is no misalignment between the front and back sides and no error when the cue mark 52 is read by the cue mark detection sensor 62.

[0072] <9.2 Second modified example> The inkjet printing device 10 according to the above embodiment is provided with only one edge detection sensor 61. However, the present invention is not limited to this. For example, as shown in FIG. 26, a configuration can be adopted in which a K-color edge detection sensor 61k, a C-color edge detection sensor 61c, an M-color edge detection sensor 61m, and a Y-color edge detection sensor 61y are provided corresponding to the K-color head unit 223k, the C-color head unit 223c, the M-color head unit 223m, and the Y-color head unit 223y, respectively. In such a configuration, the meandering amount calculation unit 420 (see FIG. 8) can determine the meandering amount of the printing paper 5 based on the position of the edge (edge ​​of the printing paper 5) detected by the corresponding edge detection sensor 61 for each of the multiple ink colors. Then, the layout processing unit 450 can determine the printing position of each image by taking into account the corresponding meandering amount (the meandering amount calculated by the meandering amount calculation unit 420) for each ink color. According to this modified example as described above, the printing position of each image is adjusted for each ink color, so that the occurrence of positional deviation (misregistration) between a plurality of colors is effectively suppressed.

[0073] <10. Supplementary Information> In the above embodiment, the CPU 111 as a processor executes the print control program 13 to realize various functions of the print control device 100. However, the present invention is not limited to the configuration using only one CPU 111 as shown in FIG. 7. A configuration using multiple processors, such as a configuration using multiple CPUs, can also be adopted. As a processor, in addition to a CPU, an MPU (Micro Processing Unit), a GPU (Graphics Processing Unit), a DSP (Digital Signal Processor), etc. can also be adopted. In addition, a combination of multiple types of processors can also be used. For example, with respect to the components in the control unit 400 shown in FIG. 8, some components and the remaining components may be realized by different processors. Furthermore, a configuration including an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit) can also be adopted.

[0074] <11.Other> In the above embodiment (including the modified example), the inkjet printing device 10 performs color printing. However, the present invention is not limited to this, and an inkjet printing device that performs monochrome printing may also be used.

[0075] In addition, in the above embodiment (including the modified example), an inkjet printer 10 using aqueous ink is used. However, the present invention is not limited to this, and an inkjet printer using UV ink (ultraviolet light curable ink) such as an inkjet printer for label printing may be used. In this case, an ultraviolet light irradiation mechanism that cures the UV ink on the printing paper 5 by irradiating it with ultraviolet light is provided inside the printing mechanism 22 (see FIG. 3) instead of the drying mechanism 224.

[0076] Furthermore, in the above embodiment (including the modified example), the inkjet printing device 10 has the printing mechanism 22a for front side printing and the printing mechanism 22b for back side printing (i.e., an inkjet printing device capable of double-sided printing). However, the present invention is not limited to this, and an inkjet printing device that does not have the printing mechanism 22b for back side printing may be used.

[0077] <12. Notes> From the above disclosure, a printing device having the following configuration is also conceivable.

[0078] A printing device that performs printing by ejecting ink onto a print medium that is elongated in a transport direction, a transport mechanism that transports the print medium in a first direction; at least one ink ejection head including a plurality of nozzles arranged in a second direction perpendicular to the first direction, and ejecting ink from the plurality of nozzles onto the print medium being transported by the transport mechanism; at least one edge detection sensor that detects the position of an edge of the print medium being transported by the transport mechanism; a mark image detection sensor for detecting a mark image to be placed at a predetermined position on the printing medium; A processor; Memory for storing programs Equipped with When the program stored in the memory is executed by the processor, the program causes the processor to perform the following operations (A), (B), and (C): (A) The amount of meandering of the print medium is determined based on the position of the edge detected by the at least one edge detection sensor. (B) Based on input image data including a plurality of images, print image data is generated by determining the print position of each image on each of a plurality of pages to be printed, taking the amount of meandering into consideration. (C) controlling the ejection of ink from the at least one ink ejection head based on the image data for printing; the plurality of pages are configured by a nozzle check page including a pattern image for detecting a discharge failure and the mark image for detecting a nozzle in a discharge failure state from among the plurality of nozzles, and a normal page including an image other than the pattern image for detecting a discharge failure and the mark image, a printing device in which, when generating the printing image data, the processor shifts the printing positions of all images for the normal page in the second direction based on the amount of meandering, with the printing positions when the amount of meandering is 0 as a reference, and, for the nozzle check page, shifts the printing positions of the mark images in the second direction based on the amount of meandering, with the printing positions when the amount of meandering is 0 as a reference, while maintaining the printing positions of the pattern images for detecting ejection defects at the printing positions when the amount of meandering is 0. [Explanation of symbols]

[0079] 5…Printing paper 7J1, 7J2...Normal pages 7NC…Nozzle check page 10...Inkjet printing device 22...Printing mechanism 51...Image printing area 52...Cue mark 61...End detection sensor 62...Cue mark detection sensor 63…Inline scanner 71…Pattern image for detecting discharge defects 75...Reference position 100...Print control device 200…Printing machine body 223…Recording Department 251...Ink ejection head 420...Meander amount calculation unit 430...Accessory generation circuit 441...Image data receiving unit 442...Printing information receiving unit 450: Layout processing section 452...Print position shift processing unit 460…Data conversion section 462...ink amount compensation processing unit 490…Inspection Department

Claims

1. A printing device that performs printing by ejecting ink onto a print medium that is elongated in a transport direction, a transport mechanism that transports the print medium in a first direction; at least one ink ejection head including a plurality of nozzles arranged in a second direction perpendicular to the first direction, and ejecting ink from the plurality of nozzles onto the print medium being transported by the transport mechanism; at least one edge detection sensor that detects the position of an edge of the print medium being transported by the transport mechanism; a meander amount calculation unit that calculates a meander amount of the print medium based on the position of the edge detected by the at least one edge detection sensor; a mark image detection sensor for detecting a mark image to be placed at a predetermined position on the printing medium; a layout processing unit that generates print image data by determining a print position of each image on each of a plurality of pages to be printed, taking the meandering amount into consideration, based on input image data including a plurality of images; an ink ejection control unit that controls the ejection of ink from the at least one ink ejection head based on the print image data; Equipped with the plurality of pages are configured by a nozzle check page including a pattern image for detecting discharge failures and the mark image for detecting nozzles in a discharge failure state from among the plurality of nozzles, and a normal page including an image other than the pattern image for detecting discharge failures and the mark image, a layout processing unit that, for the normal page, shifts the printing positions of all images in the second direction based on the meandering amount, with a printing position when the meandering amount is 0 as a reference, and, for the nozzle check page, shifts the printing position of the mark image in the second direction based on the meandering amount, with a printing position when the meandering amount is 0 as a reference, while maintaining the printing position of the pattern image for detecting ejection defects at the printing position when the meandering amount is 0.

2. the nozzle check page further includes a pattern image for position identification for identifying the position of a nozzle having a discharge defect detected based on the pattern image for detecting a discharge defect, 2. The printing device according to claim 1, wherein the layout processing section maintains the printing position of the pattern image for position identification at the printing position when the amount of meandering is zero.

3. the nozzle check page includes an accessory image; The printing device according to claim 1 , characterized in that the layout processing unit shifts the printing position of the accessory image included in the nozzle check page in the second direction based on the meandering amount, with the printing position when the meandering amount is 0 as a reference.

4. The printing device described in claim 1, characterized in that when the printing medium meanders and the printing position of at least a portion of the pattern image for detecting ejection defects falls outside the area of ​​the printing medium, the layout processing unit performs a trimming process to remove the portion of the pattern image for detecting ejection defects whose printing position falls outside the area of ​​the printing medium.

5. The printing device described in claim 4, characterized in that when the printing position of at least a portion of the pattern image for detecting ejection defects falls outside the area of ​​the printing medium due to the meandering of the printing medium, the layout processing unit expands the printing area of ​​the pattern image for detecting ejection defects by a width equivalent to the amount of meandering in the direction in which the printing medium is shifted.

6. the at least one ink ejection head includes a plurality of ink ejection heads respectively corresponding to a plurality of ink colors; the at least one edge detection sensor includes a plurality of edge detection sensors respectively corresponding to the plurality of ink ejection heads; the meandering amount calculation unit calculates the meandering amount for each of the plurality of ink colors; 2. The printing apparatus according to claim 1, wherein the layout processing section determines the print position of each image for each ink color by taking into consideration the corresponding meandering amount.

7. 7. The printing apparatus according to claim 1, further comprising an imaging device that captures the ejection failure detection pattern image recorded on the printing medium.

8. a discharge failure position specifying unit that specifies the position of a nozzle having a discharge failure based on the discharge failure detection pattern image captured by the imaging device; an ink amount compensation processing unit that corrects the printing image data so as to compensate for the amount of ink ejected onto the printing medium, based on the position of the nozzle in an ejection failure state identified by the ejection failure position identifying unit; The printing device of claim 7 further comprising:

9. A print control method for a printing device that performs printing by ejecting ink onto a print medium that is elongated in a transport direction, comprising: The printing device includes: a transport mechanism that transports the print medium in a first direction; at least one ink ejection head including a plurality of nozzles arranged in a second direction perpendicular to the first direction, and ejecting ink from the plurality of nozzles onto the print medium being transported by the transport mechanism; at least one edge detection sensor that detects the position of an edge of the print medium being transported by the transport mechanism; a mark image detection sensor for detecting a mark image to be placed at a predetermined position on the printing medium; Equipped with The printing control method includes: a meander amount calculation step of calculating a meander amount of the print medium based on the position of the edge detected by the at least one edge detection sensor; a layout processing step for generating print image data by determining the print position of each image on each of a plurality of pages to be printed, taking the meandering amount into consideration, based on input image data including a plurality of images; an ink ejection control step of controlling the ejection of ink from the at least one ink ejection head based on the print image data; Including, the plurality of pages are configured by a nozzle check page including a pattern image for detecting a discharge failure and the mark image for detecting a nozzle in a discharge failure state from among the plurality of nozzles, and a normal page including an image other than the pattern image for detecting a discharge failure and the mark image, a printing control method characterized in that, in the layout processing step, for the normal page, the printing positions of all images are shifted in the second direction based on the meandering amount, with the printing position when the meandering amount is 0 as a reference, and, for the nozzle check page, the printing position of the pattern image for detecting ejection defects is maintained at the printing position when the meandering amount is 0, and the printing position of the mark image is shifted in the second direction based on the meandering amount, with the printing position when the meandering amount is 0 as a reference.

10. A print control program for controlling an operation of a printing device that prints by ejecting ink onto a print medium that is elongated in a transport direction, comprising: a computer included in the printing device, the computer comprising: a transport mechanism that transports the print medium in a first direction; at least one ink ejection head that includes a plurality of nozzles arranged in a second direction perpendicular to the first direction and ejects ink from the plurality of nozzles onto the print medium being transported by the transport mechanism; at least one edge detection sensor that detects the position of an edge of the print medium being transported by the transport mechanism; and a mark image detection sensor that detects a mark image to be placed at a predetermined position on the print medium; a meander amount calculation step of calculating a meander amount of the print medium based on the position of the edge detected by the at least one edge detection sensor; a layout processing step for generating print image data by determining the print position of each image on each of a plurality of pages to be printed, taking the meandering amount into consideration, based on input image data including a plurality of images; an ink ejection control step of controlling the ejection of ink from the at least one ink ejection head based on the print image data; Run the command, the plurality of pages are configured by a nozzle check page including a pattern image for detecting discharge failures and the mark image for detecting nozzles in a discharge failure state from among the plurality of nozzles, and a normal page including an image other than the pattern image for detecting discharge failures and the mark image, a printing control program characterized in that, in the layout processing step, for the normal page, the printing positions of all images are shifted in the second direction based on the meandering amount, with respect to the printing position when the meandering amount is 0 as a reference, and, for the nozzle check page, the printing position of the pattern image for detecting ejection defects is maintained at the printing position when the meandering amount is 0, and the printing position of the mark image is shifted in the second direction based on the meandering amount, with respect to the printing position when the meandering amount is 0 as a reference.

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