Inkjet printing apparatus, inkjet printing method, and program

Abstract

This invention provides an inkjet printing apparatus, an inkjet printing method, and a program that enable stable color measurement. [Solution] The inkjet printing apparatus of the present invention comprises a printing unit that prints a colorimetric chart including colorimetric patches and position patches on a recording medium, a colorimetric device that detects the colorimetric chart, and a control unit, wherein the control unit performs a first control in printing the colorimetric chart such that the amount of ink adhering to the position patches is greater than the amount of ink adhering to the colorimetric patches.

Description

Technical Field

[0001] The present invention relates to an inkjet printing apparatus, an inkjet printing method, and a program.

Background Art

[0002] An image reading apparatus that acquires parameters such as the position, inclination, and magnification of a colorimetric image based on the reading result of a position measurement image is known (see Patent Document 1). The position measurement image is also referred to as a position patch.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] On the other hand, in an inkjet printing apparatus, nozzle defects in a state where ink is not ejected from the nozzles of a print head may cause problems. When such nozzle defects occur, white vertical streaks extending in the paper conveyance direction (FD direction) may occur due to dot omission. As shown in FIG. 1, when this white vertical streak L overlaps with the position patch 202, detection of the position patch by an image reading apparatus performed while conveying the paper may not be appropriately performed. As a result, stable colorimetry cannot be performed. Note that the white vertical streak L in FIG. 1 is shown larger than the actual width assumed for the sake of explanation.

[0005] The present invention has been made in view of the above situation. The problem to be solved by the present invention is to provide an inkjet printing apparatus, an inkjet printing method, and a program capable of stable colorimetry.

Means for Solving the Problems

[0006] The above-mentioned problems according to the present invention are solved by the following means.

[0007] 1. A printing unit that prints a colorimetric chart including colorimetric patches and position patches onto a recording medium, A colorimeter that detects the aforementioned colorimeter chart, It comprises a control unit and, The control unit performs a first control in printing the colorimetric chart such that the amount of ink adhering to the position patch is greater than the amount of ink adhering to the colorimetric patch. Inkjet printing device.

[0008] 2. The control unit performs the first control by making the ink dot diameter in the position patch larger than the ink dot diameter in the colorimetric patch. The inkjet printing apparatus described in paragraph 1.

[0009] 3. Before the first control, do not detect the nozzle defect position. The inkjet printing apparatus described in paragraph 1.

[0010] 4. The control unit performs the first control by ejecting ink multiple times from the same nozzle at the same position during printing of the position patch. The inkjet printing apparatus described in paragraph 1.

[0011] 5. The control unit performs the first control by ejecting two or more inks at the same position during the printing of the position patch. The inkjet printing apparatus described in paragraph 1.

[0012] 6. The control unit performs the first control by relaxing the ink amount limit value when printing the position patch. The inkjet printing apparatus described in paragraph 1.

[0013] 7. The control unit performs the first control during the printing of the colorimetric chart, which is performed during a normal job or between consecutive normal jobs. The inkjet printing apparatus according to claim 1.

[0014] 8. The recording medium is printing paper, and the control unit changes an increase amount of an ink adhesion amount to the position patch with respect to an ink adhesion amount to the colorimetric patch in the first control according to a paper type of the printing paper. The inkjet printing apparatus according to claim 1.

[0015] 9. In the first control, the control unit increases an ink adhesion amount only to edge regions of four sides in the position patch. The inkjet printing apparatus according to claim 1.

[0016] 10. In the first control, the control unit increases an ink adhesion amount only to an edge region in a recording medium conveyance direction in the position patch. The inkjet printing apparatus according to claim 1.

[0017] 11. The colorimetric device includes a single-wavelength reflection-type optical fiber sensor or a reflection-type color sensor as a position sensor that detects the position patch. The inkjet printing apparatus according to claim 1.

[0015] 9. In the first control, the control unit increases an ink adhesion amount only to edge regions of four sides in the position patch. The inkjet printing apparatus according to claim 1.

[0016] The inkjet printing apparatus according to claim 1.

[0015] 9. In the first control, the control unit increases an ink adhesion amount only to edge regions of four sides in the position patch. The inkjet printing apparatus according to claim 1.

[0016] 10. In the first control, the control unit increases an ink adhesion amount only to an edge region in a recording medium conveyance direction in the position patch The inkjet printing apparatus according to claim 1.

[0017] 11. The colorimetric device includes a single-wavelength reflection-type optical fiber sensor or a reflection-type color sensor as a position sensor that detects the position patch. The inkjet printing apparatus according to claim 1.

[0018] 12. The printing unit prints the colorimetric chart in a single-pass method. The inkjet printing apparatus according to claim 1.

[0019] 13. The printing unit prints the colorimetric chart using ultraviolet curable ink. The inkjet printing apparatus according to claim 1.

[0020] 14. A chart printing step in which the printing unit prints a colorimetric chart including a colorimetric patch and a position patch on a recording medium, and a colorimetric step in which the colorimetric device detects the colorimetric chart. In the chart printing process, the control unit performs a first control to make the amount of ink adhering to the position patch greater than the amount of ink adhering to the colorimetric patch. Inkjet printing method.

[0021] 15. An inkjet printing apparatus comprising a printing unit for printing a colorimetric chart including colorimetric patches and position patches on a recording medium, a colorimetric device for detecting the colorimetric chart, and a computer, wherein the computer is... In printing the colorimetric chart, the control unit functions as a first control that makes the amount of ink adhering to the position patch greater than the amount of ink adhering to the colorimetric patch. program. [Effects of the Invention]

[0022] According to the present invention, it is possible to provide an inkjet printing apparatus, an inkjet printing method, and a program that enable stable color measurement. [Brief explanation of the drawing]

[0023] [Figure 1] This figure shows a colorimetric chart with white streaks. [Figure 2] This is a schematic diagram of one embodiment of an inkjet printing apparatus. [Figure 3] This is a block diagram showing the functional configuration of one embodiment of an inkjet printing apparatus. [Figure 4] This is a schematic diagram of one embodiment of a colorimeter. [Figure 5] This figure shows an example of a colorimetric chart. [Figure 6] This flowchart shows an example of the process from printing to outputting a colorimetric chart. [Figure 7] This flowchart shows a detailed example of the CD location patch detection operation. [Figure 8] This flowchart shows a detailed example of the colorimetric measurement process. [Figure 9]This flowchart shows an example of a typical job flow. [Figure 10] This flowchart shows an example of a colorimetric job flow. [Figure 11] This figure illustrates a portion of a colorimetric chart printed based on the first processing step. [Figure 12] This figure illustrates a portion of a colorimetric chart printed based on the first processing step. [Figure 13] This figure illustrates a portion of a colorimetric chart printed based on the first processing step. [Figure 14] This figure illustrates a portion of a colorimetric chart printed based on the first processing step. [Figure 15] This diagram schematically shows the ink dots relative to the dot area in a colorimetric patch. [Figure 16] This diagram schematically shows the ink dots in the dot area of ​​a position patch. [Figure 17] This diagram schematically shows the ink dots in the dot area of ​​a position patch. [Figure 18] This figure shows a position patch with a high ink coverage across its entire surface. [Figure 19] This figure shows a position patch where the amount of ink applied is increased only to the edge regions of all four sides. [Figure 20] This figure shows a position patch in which the amount of ink applied is increased only to the edge regions on both sides in the direction of medial recording transport. [Figure 21] This figure shows a position patch in which the amount of ink applied is increased only to the front edge region in the direction of media transport. [Modes for carrying out the invention]

[0024] The following description illustrates one or more embodiments of the present invention with reference to the drawings. The effects and features of the embodiments of the present invention will be understood from the following detailed description and drawings. The following detailed description and drawings are provided for illustrative purposes only and do not limit the scope of the present invention.

[0025] Figure 2 is a schematic diagram of one embodiment of the inkjet printing apparatus 1 of the present invention. Figure 3 is a block diagram showing the functional configuration of one embodiment of the inkjet printing apparatus 1 of the present invention.

[0026] As shown in Figures 2 and 3, the inkjet printing apparatus 1 may include a paper feeding unit 2, a transport unit 3, a printing unit 4, an image scanning unit 5, a paper discharge unit 6, a colorimeter 7, a control unit 8, and an operation unit 9.

[0027] The paper feeding unit 2 stores the recording medium M. The paper feeding unit 2 has, for example, a tray. Examples of recording medium M include printing paper, fabric, sheet-like resin, etc. Examples of printing paper include plain paper, coated paper, etc.

[0028] As shown in Figure 2, the transport unit 3 includes, for example, a feeder board 31, a first transfer drum 32, a transport drum 33, a second transfer drum 34, and an unloading unit 35.

[0029] The feeder board 31 transports the recording medium M from the paper feeding unit 2 to the first transfer drum 32. The first transfer drum 32 holds one end of the recording medium M transported by the feeder board 31, picks it up, and transfers it to the transport drum 33.

[0030] The transport drum 33 is, for example, cylindrical. The side surface of the transport drum 33 serves as a transport surface that attracts and holds the recording medium M. With the recording medium M held on the transport surface, the transport drum 33 rotates in one direction around its central axis as the axis of rotation. As a result, the transport drum 33 transports the recording medium M, which is attracted and held on the transport surface, along the transport surface.

[0031] The printing unit 4 may have, for example, one or more head units 41. The printing unit 4 performs printing jobs to produce printed materials using an inkjet method. Each head unit 41 has one or more inkjet heads. The head unit 41 may have an ink ejection surface at a position facing the transport surface of the transport drum 33. The head unit 41 ejects ink onto the recording medium M held in the transport drum 33 at an appropriate timing corresponding to the rotation of the transport drum 33 to form an image and produce a printed material P. The ink is not particularly limited, but for example, an ultraviolet-curing ink may be used.

[0032] In the inkjet printing apparatus 1 illustrated in Figure 2, four head units 41 are arranged at predetermined intervals, starting from the upstream side in the rotational direction of the transport drum 33. The four head units 41 correspond to, for example, four colors of ink: yellow, magenta, cyan, and black. The printing method is not limited, but for example, it is a single-pass method. The single-pass method is a method of printing in a single pass using one or more head units 41 that cover the entire area in the width direction of the recording medium M. In conventional inkjet printing apparatuses, white vertical streaks are likely to occur in the single-pass method if a nozzle failure occurs. However, in the inkjet printing apparatus of the present invention, white vertical streaks are less likely to occur even in the single-pass method due to the first control described later.

[0033] The printing unit 4 may have an ultraviolet irradiation unit 42 downstream of the head unit 41 in the transport direction. If the ink is an ultraviolet-curable ink, the ultraviolet irradiation unit 42 can cure the ink on the recording medium M by irradiating it with ultraviolet light.

[0034] Printing unit 4 performs printing jobs such as regular jobs and color measurement jobs. A regular job is a printing job that produces a regular printed material P1 that is not subject to color measurement. A color measurement job is a printing job that produces a color measurement chart printed material P2 on which a color measurement chart is printed.

[0035] The image scanning unit 5 illuminates the printed material P with light from a light source and reads the reflected image in order to read information such as whether there are defects in the printed material P and the location of nozzle defects. The image scanning unit 5 is composed of, for example, an inline sensor in which multiple detection elements are arranged along a direction perpendicular to the transport direction of the printed material (width direction). The image data read by the image scanning unit 5 is sent to, for example, the control unit 8.

[0036] The second transfer drum 34 holds and picks up one end of the printed material transported by the transport drum 33 and hands it over to the discharge unit 35.

[0037] The discharge section 35 is the discharge route for printed materials, and it transports the printed materials to the paper discharge section 6 or the colorimeter 1. Specifically, the discharge section 35 transports regular printed materials P1 produced in a regular job to the paper discharge section 6, and transports colorimeter chart printed materials P2 produced in a colorimeter job to the colorimeter 7. The discharge section 35 is composed of, for example, a belt, rollers, etc. The transport route in the discharge section 35 may branch along the way, as shown in Figure 2. The paper discharge section 6 has, for example, a tray.

[0038] The colorimeter 7 is a device that detects the colorimeter chart 200 and can be arranged inline with the inkjet printing device 1. Figure 4 is a configuration diagram showing an example of the colorimeter 7. As shown in Figure 4, the colorimeter 7 includes, for example, a colorimeter head 71, a first motor 72, a second motor 73, a paper leading edge detection sensor 74, a paper trailing edge detection sensor 75, a left home sensor 76, a right home sensor 77, and a white calibration plate 78. The colorimeter head 71 includes a colorimeter sensor 71a and a position sensor 71b. The colorimeter sensor 71a optically detects and measures the colorimeter patch. Colorimetering is the measurement of color information, for example, L * a * b *The purpose is to measure color values ​​such as values. As the colorimeter 71a, for example, a spectrophotometer that measures color by spectrally analyzing reflected light from a colorimeter patch can be used. The position sensor 71b detects the position patch. The position sensor 71b is, for example, mechanically mounted adjacent to the colorimeter 71a and is movable together with the colorimeter 71a. The first motor 72, when driven, moves the colorimeter head 71 back and forth in the main scanning direction (CD direction, Cross Direction). The second motor 73, when driven, transports the colorimeter chart printout P2 in the sub-scanning direction (FD direction, Feed Direction) perpendicular to the main scanning direction. The paper leading edge detection sensor 74 and the paper trailing edge detection sensor 75 detect the leading edge and trailing edge of the colorimeter chart printout P2, respectively. The left home sensor 76 and the right home sensor 77 detect the left and right limit positions when the colorimeter 71a is moved. The white calibration plate 78 is used to calibrate the colorimeter 71a.

[0039] The position sensor 71b is preferably a single-wavelength reflective optical fiber sensor or a reflective color sensor. A single-wavelength reflective optical fiber sensor or a reflective color sensor exhibits different differences in the amount of light received in the white region and the amount of light received in the black region depending on its distance from the position patch to be detected. Specifically, the smaller the distance from the position patch, the larger the difference between the amount of light received in the white region and the amount of light received in the black region, resulting in better sensitivity. On the other hand, when the distance between the position sensor 71b and the position patch is small, the detection range becomes narrower, making it susceptible to the effects of white vertical streaks caused by nozzle defects. However, in the present invention, the first control described later makes it less likely for white vertical streaks to occur, allowing the distance between the position sensor 71b and the position patch to be reduced. Therefore, by using a single-wavelength reflective optical fiber sensor or a reflective color sensor, sensitivity can be improved when the distance between the position sensor 71b and the position patch is reduced, enabling more stable color measurement.

[0040] The control unit 8 controls the operation of other functional components according to print image data, print settings, etc. The control unit 8 is a computer and includes, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), and ROM (Read Only Memory). The CPU executes various control programs to drive and control the inkjet printer 1 and performs various calculations. RAM provides the CPU with a working memory space and stores temporary data. RAM may include non-volatile memory. ROM stores various control programs executed by the CPU, setting data, etc. Rewritable non-volatile memory such as flash memory may be used instead of ROM. The control unit 8 can perform the first control described later. The control unit 8 may have an overall control unit 81 that performs overall control of the inkjet printer 1 and a print control unit 82 that controls printing operations and performs image processing.

[0041] The overall control unit 81 may be an external device, such as a client's personal computer. The overall control unit 81 generates print data based on print jobs, such as regular jobs and color measurement jobs. Specifically, the overall control unit 81 generates print data by performing RIP (Raster Image Processor) processing to convert image data into a raster image, color correction, and conversion to a printable bitmap format. The generated print data is then transmitted to, for example, the print control unit 82. Note that the print data does not necessarily have to be data generated by the overall control unit; it may be data that has been stored in advance. The overall control unit 81 may also perform other functions, such as control for executing print jobs and purging to transport the color measurement chart printout P2 to the colorimeter 7 instead of the paper output unit 6.

[0042] The print control unit 82, for example under the control of the overall control unit 81, controls the operation of the transport unit 3, the printing unit 4, the image scanning unit 5, etc., to produce a printed material P. Specifically, the print control unit 82 determines the ink ejection amount, performs image processing, processes colorimetric data, controls the head unit drive, controls ultraviolet irradiation, controls transport, determines the ink ejection method, determines the ink amount limit value, acquires nozzle defect information, acquires paper type information, etc., to produce a printed material.

[0043] The control panel can be used by the user to input various settings for printing, information for creating ICC profiles, and so on.

[0044] Figure 5 shows an example of a colorimetric chart 200. The colorimetric chart 200 illustrated in Figure 5 has a plurality of colorimetric patches 201 and a plurality of position patches 202.

[0045] Multiple colorimetric patches 201 consist of multiple columns arranged in the CD direction and multiple rows arranged in the FD direction. The frontmost row of the multiple rows is the first row. The front side refers to the front side in the transport direction of the colorimetric chart printout P2. Multiple position patches 202 include CD position patches 202a whose main purpose is to indicate position information in the CD direction and FD position patches 202b whose main purpose is to indicate position information in the FD direction.

[0046] Multiple CD position patches 202a are located in front of the colorimetric patch 201, and are spaced apart from each other in the CD direction.

[0047] Multiple FD position patches 202b are positioned on either the left or right side of the colorimetric patch 201, or both sides, spaced apart from each other in the FD direction. Each FD position patch 202b is positioned such that its position in the FD direction coincides with each row of the colorimetric patch 201. Specifically, each FD position patch 202b aligned in the FD direction on the left side of the colorimetric patch 201 is positioned such that its position in the FD direction coincides with each odd-numbered row of the colorimetric patch 201. Each FD position patch 202b aligned in the FD direction on the right side of the colorimetric patch 201 is positioned such that its position in the FD direction coincides with each even-numbered row of the colorimetric patch 201. In this invention, "left side" refers to the left side when the colorimetric chart printout P2 is being transported. "Right side" refers to the right side when the colorimetric chart printout P2 is being transported.

[0048] The above description is an illustration of the colorimetric chart 200 shown in Figure 5, and does not limit the colorimetric chart 200 according to the present invention.

[0049] Figure 6 is a flowchart showing an example of the flow from printing to discharge of the colorimetric chart 200. In step S1-1, the printing unit 4 produces the colorimetric chart printout P2. In step S1-2, the transport unit 3 transports the colorimetric chart printout P2 to the colorimetric device 7. In step S1-3, the colorimetric device 7 performs CD position patch detection. In step S1-4, the colorimetric device 7 performs color measurement. In step S1-5, the colorimetric device 7 transmits the color measurement data to the print control unit 82. In step S1-6, the colorimetric device 7 discharges the colorimetric chart printout P2.

[0050] Although not shown in the flowchart of Figure 6, the print control unit 82 may transmit the received color measurement data to the overall control unit 81. Based on the obtained color measurement data, the overall control unit 81 may perform control related to print image adjustment, such as color proofing and ICC profile creation. The transmission of color measurement data to the print control unit 82 (step S1-5) may be performed each time a color measurement patch 201 is measured, each time the color measurement operation for a row to be measured is completed, or all at once after all color measurement patches 201 have been measured.

[0051] Figure 7 is a flowchart showing a detailed example of the CD position patch detection operation (steps S1-3). In step S2-1, the first motor 72 moves the colorimetric head 71 in the CD direction so that the position sensor 71b is in a position to detect the leftmost CD position patch 202a, and waits for the colorimetric chart printout P2 to be transported. In step S2-2, when the paper leading edge detection sensor 74 detects the leading edge of the transported colorimetric chart printout P2, the flow proceeds to step S2-3. In step S2-3, the second motor 73 is driven to continue transporting the colorimetric chart printout P2 in the FD direction. In step S2-4, when the position sensor 71b detects the leftmost CD position patch 202a, the flow proceeds to step S2-5. In step S2-5, the second motor 73 stops transporting the colorimetric chart printout P2. In step S2-6, the first motor 72 moves the colorimetric head 71 from the left end to the right end, and at this time, the position sensor 71b acquires the position information of each CD position patch 202a. From the position information of each CD position patch 202a, the size of the colorimetric patch 201, the colorimetric timing, etc. are calculated and the calculated values ​​are stored for subsequent colorimetric operations. In step S2-7, the first motor 72 moves the colorimetric head 71 to the left end in the CD direction and stops it until the position sensor 71b is in a position to detect the left FD position patch 202b.

[0052] Figure 8 is a flowchart showing a detailed example of the color measurement operation (steps S1-4). In step S3-1, the second motor 73 is driven to transport the color measurement chart printout P2 in the FD direction. In step S3-2, when the position sensor 71b detects the FD position patch 202b of the transported color measurement chart printout P2, the flow proceeds to step S3-3. In step S3-3, the second motor 73 stops transporting the color measurement chart printout P2. In step S3-4, it is determined whether the next row to be measured is an odd-numbered row. If the next row to be measured is an odd-numbered row, the flow proceeds to step S3-5. In step S3-5, the color measurement sensor 71a moves to the white calibration plate 78 and is calibrated. In step S3-6, the color measurement sensor 71a measures each color measurement patch 201 while moving in the CD direction. At this time, the direction of movement of the colorimetric sensor 71a is from left to right if the row to be measured is odd-numbered, and from right to left if the row to be measured is even-numbered. If it is determined in step S3-7 that the last colorimetric patch 201 of the row to be measured has been measured, the flow proceeds to step S3-8. In step S3-8, the measurement head 71 is moved a predetermined distance in the CD direction and then stopped. If it is determined in step S3-9 that the measurement of all colorimetric patches 201 has been completed, the flow ends. If it is not determined that the measurement of all colorimetric patches 201 has been completed, the flow returns to step S3-1.

[0053] Figure 9 is a flowchart showing an example of a typical job flow. In step S4-1, the control unit 8 receives a print job and acquires image data to be printed. In step S4-2, the control unit 8 performs RIP processing on the acquired image data to convert RGB data to CMYK data. In step S4-3, the control unit 8 performs halftone screening processing on each color data to convert the binary data to, for example, 256 gradation values. In step S4-4, the control unit 8 converts the gradation values ​​into the amount of ink to be ejected, for example, 5 levels of ink. In step S4-5, the control unit 8 performs ink amount limiting processing. In step S4-6, the control unit 8 sets the ink ejection method. In step S4-7, based on the control by the control unit 8, the printing unit 4 produces a normal printed document P1.

[0054] Figure 10 is a flowchart showing an example of the color measurement job flow. In step S5-1, the control unit 8 receives an instruction to perform a color measurement operation and acquires the print data of the pre-generated color measurement chart 200. The control unit 8 also acquires information such as the paper type of the recording medium M. In step S5-2, the control unit 8 identifies the area in the print data of the color measurement chart 200 where the position patch 202 will be printed. In step S5-3, the control unit 8 performs a first control to make the amount of ink adhering to the position patch 202 greater than the amount of ink adhering to the color measurement patch 201. In step S5-4, based on the control including the first control by the control unit 8, the printing unit 4 produces the color measurement chart printout P2.

[0055] As mentioned above, in conventional inkjet printing devices, nozzle failure can cause white vertical streaks L, as shown in Figure 1. If these white vertical streaks L overlap with the position patch 202, it becomes difficult to properly detect the position patch 202, making stable color measurement impossible. As a countermeasure, conventionally, when a condition occurred where ink was not ejected from a nozzle, the nozzle failure location was detected, and then "nozzle failure correction" was performed to correct the dot data that should have been printed by distributing it to surrounding nozzles. If nozzle failure correction is performed properly, white vertical streaks L are less likely to occur. However, since nozzle failure can occur suddenly, it is difficult to always perform appropriate nozzle failure correction. In contrast, in the inkjet printing device 1 of the present invention, the amount of ink adhering to the position patch 202 is greater than the amount of ink adhering to the color measurement patch 201 by the first control. As a result, even if a nozzle failure occurs in the nozzle that ejects ink to the position patch 202, white vertical streaks L are less likely to occur on the position patch 202. Therefore, stable color measurement is possible in the inkjet printing device 1 of the present invention.

[0056] In the inkjet printing apparatus 1 of the present invention, the first control makes it less likely for white vertical streaks to appear on the position patch 202 even if a nozzle defect occurs in the nozzle that ejects ink to the position patch 202. Therefore, the inkjet printing apparatus 1 of the present invention does not need to detect the nozzle defect position before the first control.

[0057] The control unit 8 may perform the first control by making the ink dot diameter in the position patch 202 larger than the ink dot diameter in the colorimetric patch 201. The control unit 8 may perform the first control by ejecting ink multiple times from the same nozzle at the same position during printing of the position patch 202. The control unit 8 may perform the first control by ejecting two or more colors of ink at the same position during printing of the position patch 202. The control unit 8 may perform the first control by relaxing the ink amount limit during printing of the position patch 202.

[0058] Figures 11 to 14 illustrate portions of the colorimetric chart 200 printed based on the first processing, showing the position patch 202 and the colorimetric patch 201 side by side. Colorimetric patch 201k is one of several colorimetric patches 201.

[0059] In Figure 11, the position patch 202 and the colorimetric patch 201k are printed in black (K) alone. Here, the amount of ink adhering to the position patch 202 is greater than the amount of ink adhering to the colorimetric patch 201k.

[0060] In Figure 12, the position patch 202 and the colorimetric patch 201k are printed in black. Assuming that the maximum value for solid black is 100%, the colorimetric patch 201k is printed with K100%, while the position patch 202 is printed with black using K100% + C100%. As a result, the amount of ink adhering to the position patch 202 is greater than the amount of ink adhering to the colorimetric patch 201k.

[0061] In Figure 13, both the position patch 202 and the colorimetric patch 201k are printed in black. Assuming that the maximum value for solid black is 100%, the colorimetric patch 201k is printed with K100%, while the position patch 202 is printed with black using K100%+C50%+M40%+Y40%. As a result, the amount of ink adhering to the position patch 202 is greater than the amount adhering to the colorimetric patch 201k.

[0062] In Figure 14, the position patch 202 and the colorimetric patch 201k are printed in black. Here, the ink amount limit for the colorimetric patch 201k is limited to 320% (K80%+C80%+M80%+Y80%), while the ink amount limit for the position patch 202 is relaxed to 400%. As a result, the amount of ink adhering to the position patch 202 is greater than the amount of ink adhering to the colorimetric patch 201k.

[0063] Figures 15 to 17 illustrate an example of control where the ink dot diameter in position patch 202 is larger than the ink dot diameter in colorimetric patch 201.

[0064] Figure 15 schematically shows the ink dot 302 relative to the dot area 301 in the colorimetric patch 201. Figure 16 schematically shows the ink dot 302 relative to the dot area 301 in the position patch 202. In this example, as shown in Figure 15, the ink dot 302 in the colorimetric patch 201 is contained within the dot area 301. In contrast, as shown in Figure 16, the ink dot 302 in the position patch 202 extends into the adjacent dot area 301. That is, the ink dot diameter in the position patch 202 is larger than the ink dot diameter in the colorimetric patch 201.

[0065] Figure 17 shows an example where the ink dot diameter in position patch 202 is even larger than in Figure 16. In Figure 17, the ink dot 302 extends more than halfway into the adjacent dot area 301. In this case, even if a nozzle defect of one dot occurs, ink is filled in from the adjacent dot area 301. In other words, nozzle defect correction is performed even if the nozzle defect position is not detected before the first control.

[0066] The ink dot diameter can be increased, for example, by increasing the amount of ink ejected in a single ink ejection or by ejecting ink multiple times from the same nozzle at the same position.

[0067] Figures 18 to 21 show the region A1 in position patch 202 where the amount of ink applied is increased by the first control, and the region A2 where the amount of ink applied is not increased.

[0068] As shown in Figure 18, in the first control, the control unit 8 may set the amount of ink deposited on the entire area of ​​the position patch 202 to be greater than the amount of ink deposited on the colorimetric patch 201.

[0069] As shown in Figure 19, in the first control, the control unit 8 may set the amount of ink deposited on the edge regions of the four sides of the position patch 202 to be greater than the amount of ink deposited on the colorimetric patch 201. This reduces the amount of ink used. In this case, the amount of ink deposited on areas other than the edge regions of the four sides may be the same as the amount of ink deposited on the colorimetric patch 201. The "edge region" refers to, for example, an area within a certain distance from the edge of the position patch 202. The distance from the edge of the position patch 202 that constitutes the edge region can be arbitrarily determined, for example, to be less than or equal to the spot diameter of the position sensor 71b. The spot diameter of the position sensor 71b is the diameter of the detection range on the paper by the position sensor 71b, for example, 2 to 3 mm.

[0070] As shown in Figure 20, in the first control, the control unit 8 may make the amount of ink deposited on the edge regions on both sides of the recording medium transport direction (FD direction) of the position patch 202 greater than the amount of ink deposited on the colorimetric patch 201. This further reduces the amount of ink used. In this case, the amount of ink deposited on regions other than the edge regions on both sides of the recording medium transport direction (FD direction) may be the same as the amount of ink deposited on the colorimetric patch 201.

[0071] As shown in Figure 21, in the first control, the control unit 8 may increase the amount of ink deposited on the front edge region of the position patch 202 in the recording medium transport direction (FD direction) to more than the amount of ink deposited on the colorimetric patch 201. This further reduces the amount of ink used. In this case, the amount of ink deposited on regions other than the front edge region in the recording medium transport direction (FD direction) may be the same as the amount of ink deposited on the colorimetric patch 201.

[0072] The control unit 8 may perform the first control when printing the colorimetric chart 200 during a normal job or between consecutive normal jobs. Printing the colorimetric chart 200 during a normal job or between consecutive normal jobs requires even greater accuracy because a normal job will start immediately afterward. Therefore, the first control is more effective when printing the colorimetric chart 200 at such a timing. However, the control unit is not limited to this, and may also perform the first control when printing the colorimetric chart 200, for example, before the start of a normal job.

[0073] The control unit may change the amount of increase in the amount of ink deposited on the position patch 202 relative to the amount of ink deposited on the colorimetric patch 201 in the first control, depending on the type of recording medium M. If the recording medium M is printing paper, the control unit may change the amount of increase in the amount of ink deposited on the position patch 202 relative to the amount of ink deposited on the colorimetric patch 201 in the first control, depending on the type of printing paper. This makes it easier to appropriately adjust the amount of increase in the amount of ink deposited, taking into account that there are differences in the shape of the ink dots 302 formed on the recording medium M depending on the type of recording medium M, and in the case of the recording medium M, depending on the type of printing paper.

[0074] [Inkjet printing method] The inkjet printing method of the present invention comprises a chart printing step and a colorimetric step. In the chart printing step, the printing unit 4 prints a colorimetric chart 200 including colorimetric patches 201 and position patches 202 onto the recording medium M. In this chart printing step, the control unit 8 performs the first control described above. In the colorimetric step, the colorimetric device 7 detects the colorimetric chart 200 printed on the recording medium M.

[0075] [program] The program of the present invention is a program that causes the computer provided in the inkjet printing apparatus 1 described above to function as a control unit 8 that performs the first control described above.

[0076] The above description and drawings are for illustrative purposes only and do not intend to limit the scope of the present invention. The scope of the present invention should be interpreted as stated in the claims. [Explanation of symbols]

[0077] 1. Inkjet printing device 2 Paper feed section 3. Conveying section 31 Feeder board 32. First handover drum 33 Conveyor Drum 34. Second handover drum 35. Loading section 4 Printing Department 41 Head Unit 42 UV irradiation area 5. Image scanning unit 6. Paper output section 7 Colorimetric device 71 Colorimeter head 71a Colorimeter 71b Position sensor 72 First Motor 73 Second Motor 8 Control Unit 81 Overall Control Unit 82 Printing Control Unit 9 Control section 200 Colorimetric Chart 201 Colorimetric Patch 202 Location Patch 202a CD Location Patch 202b FD location patch 301 dot area 302 Ink Dot M recording medium P1 Normal printed matter P2 Colorimetric Chart Printed Material

Claims

1. A printing unit that prints a colorimetric chart including colorimetric patches and position patches onto a recording medium, A colorimeter that detects the aforementioned colorimeter chart, It comprises a control unit and, The control unit performs a first control in printing the colorimetric chart, such that the amount of ink adhering to the position patch is greater than the amount of ink adhering to the colorimetric patch. Inkjet printing device.

2. The control unit performs the first control by making the ink dot diameter in the position patch larger than the ink dot diameter in the colorimetric patch. The inkjet printing apparatus according to claim 1.

3. Before the first control, the nozzle defect position is not detected. The inkjet printing apparatus according to claim 1.

4. The control unit performs the first control by ejecting ink multiple times from the same nozzle at the same position during the printing of the position patch. The inkjet printing apparatus according to claim 1.

5. The control unit performs the first control by ejecting two or more inks at the same position during the printing of the position patch. The inkjet printing apparatus according to claim 1.

6. The control unit performs the first control by relaxing the ink amount limit value during printing of the position patch. The inkjet printing apparatus according to claim 1.

7. The control unit performs the first control during the printing of the colorimetric chart, which is performed during a normal job or between consecutive normal jobs. The inkjet printing apparatus according to claim 1.

8. The recording medium is printing paper, The control unit changes the amount by which the amount of ink deposited on the position patch is increased relative to the amount of ink deposited on the colorimetric patch in the first control, according to the type of paper used for printing. The inkjet printing apparatus according to claim 1.

9. In the first control, the control unit increases the amount of ink applied only to the edge regions of the four sides of the position patch. The inkjet printing apparatus according to claim 1.

10. The control unit, in the first control, increases the amount of ink applied only to the edge region in the recording medium transport direction of the position patch. The inkjet printing apparatus according to claim 1.

11. The colorimeter includes a single-wavelength reflective optical fiber sensor or a reflective color sensor as a position sensor for detecting the position patch. The inkjet printing apparatus according to claim 1.

12. The printing unit prints the colorimetric chart using a single-pass method. The inkjet printing apparatus according to claim 1.

13. The printing unit prints the colorimetric chart using ultraviolet-curable ink. The inkjet printing apparatus according to claim 1.

14. A chart printing process in which the printing unit prints a colorimetric chart including colorimetric patches and position patches onto a recording medium, The colorimeter has a colorimeter step in which the colorimeter device detects the colorimeter chart, In the chart printing process, the control unit performs a first control to make the amount of ink adhering to the position patch greater than the amount of ink adhering to the colorimetric patch. Inkjet printing method.

15. An inkjet printing apparatus comprising a printing unit that prints a colorimetric chart including colorimetric patches and position patches on a recording medium, a colorimetric device that detects the colorimetric chart, and a computer, wherein the computer is... In printing the colorimetric chart, the control unit functions as a first control that makes the amount of ink adhering to the position patch greater than the amount of ink adhering to the colorimetric patch. program.

Images