Liquid discharge device, control method for correcting liquid discharge device, and recording medium

Abstract

According to one aspect of the present disclosure, a liquid discharge device is a liquid discharge device for forming an image on a recording medium, the liquid discharge device including a first image obtaining unit, a second image generating unit, a correction unit and a liquid discharge unit, the first image obtaining unit being configured to obtain first image data, the second image generating unit being configured to generate second image data by adding a predetermined graphic to the first image data, the correction unit being configured to generate third image data, the third image data being obtained by correcting the first image data based on the second image data and read image data for each page, wherein the read image data is obtained by reading an image formed on the recording medium based on the second image data, and the liquid discharge unit being configured to discharge liquid onto the recording medium based on the third image data.

Description

Technical Field

[0001] The present disclosure relates to a liquid discharge apparatus, a control method for correcting the liquid discharge apparatus, and a recording medium. Background Art

[0002] Generally, for an image forming apparatus that forms an image onto a recording medium, there is known a technology for correcting an image formed on the recording medium when the formation position of the image on the recording medium is positionally shifted or the image is deformed.

[0003] Furthermore, there is disclosed a technique for correcting an image based on a detection result of a pattern formed on an image carrier (for example, see Patent Document 1).

[0004] Reference List

[0005] Patent Literature

[0006] [PTL 1] Japanese Unexamined Patent Application Publication No. 2010-210651 Summary of the Invention

[0007] Technical issues

[0008] However, in a liquid discharge device that forms an image onto a recording medium, the expansion and contraction rates of the recording medium vary from page to page depending on image formation conditions such as the image formation speed or the amount of liquid to be discharged, and therefore, using the technology of Patent Document 1, it may not be possible to correct the image with a high degree of accuracy.

[0009] An object of the present disclosure is to ensure correction accuracy for correcting an image in a liquid discharge device.

[0010] Solution to the problem

[0011] A liquid discharge device according to one aspect of the present disclosure is a liquid discharge device for forming an image on a recording medium, including:

[0012] a first image obtaining unit configured to obtain first image data;

[0013] a second image generating unit configured to generate second data by adding a predetermined graphic to the first image data;

[0014] a correction unit configured to generate third image data obtained by correcting the first image data for each page based on both the second image data and read image data obtained by reading an image formed on the recording medium based on the second image data; and

[0015] A liquid discharge unit is configured to discharge liquid onto the recording medium based on the third image data.

[0016] Beneficial effects of the present invention

[0017] According to the present disclosure, it is possible to ensure the correction accuracy for correcting an image in a liquid discharge device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a block diagram illustrating an example of the overall configuration of a liquid discharge apparatus according to an embodiment.

[0019] Figure 2 is a drawing showing an example of the configuration of a printer according to the embodiment.

[0020] Figure 3 is a block diagram illustrating an example of a hardware configuration of a DFE according to an embodiment.

[0021] Figure 4 is a block diagram illustrating an example of a hardware configuration of an image processing unit according to the embodiment.

[0022] Figure 5 is a block diagram illustrating an example of a functional configuration of an image processing unit according to the first embodiment.

[0023] Figure 6 1 is a flowchart illustrating an example of the overall configuration of the liquid discharge device according to the embodiment.

[0024] Figure 7 1 is a flowchart illustrating an example of a correction value obtaining operation of the liquid discharge device according to the embodiment.

[0025] Figure 8 FIG. 1 is a flowchart illustrating an example of a correction image forming operation of the liquid discharge device according to the embodiment.

[0026] Figure 9 is a drawing showing an example of a list screen of print jobs.

[0027] Figure 10 is a drawing showing a first example of the image position correction setting screen.

[0028] Figure 11 is a drawing showing a second example of the image position correction setting screen.

[0029] Figure 12 is a drawing showing a third example of the image position correction setting screen.

[0030] Figure 13: is a flowchart illustrating an example of a correction value obtaining operation using a test print performed by the liquid discharge apparatus according to this embodiment.

[0031] Figure 14 : is a diagram showing an example of a combination list of correction image forming modes.

[0032] Figure 15 is a flowchart illustrating an example of a correction operation of the liquid discharge apparatus according to this embodiment using a correction value.

[0033] Figure 16 : is a timing chart showing an example of the correction operation of the liquid discharge apparatus according to this embodiment using the correction value.

[0034] Figure 17 are drawings showing examples of marks added to drawing data.

[0035] Figure 18A 1 is a diagram showing coordinate points of raster image data to be labeled for explaining an example of a method of correcting image deformation.

[0036] Figure 18B 1 is a diagram showing coordinate points of read image data for explaining an example of a correction method of image deformation.

[0037] Figure 19 : is a drawing showing an example of an image formation result in which correction according to the embodiment is not performed.

[0038] Figure 20 is a diagram illustrating an example of raster image data in which correction according to the embodiment is performed.

[0039] Figure 21 is a diagram illustrating an example of raster image data in which correction according to the embodiment is performed.

[0040] Figure 22 is a block diagram showing an example of a functional configuration of an image processing unit according to the second embodiment.

[0041] Figure 23 is a diagram showing an example of an ideal variable printing result.

[0042] Figure 24 : is a drawing showing an example of a variable printing result in which correction according to the embodiment is not performed.

[0043] Figure 25 : is a drawing showing an example of a variable printing result in which correction according to the third embodiment is performed.

[0044] Figure 26 2 are drawings showing examples of marking according to the fourth embodiment.

[0045] Figure 27 : is a diagram illustrating a first example of correction according to the fourth embodiment.

[0046] Figure 28 2 is a diagram illustrating a second example of correction according to the fourth embodiment.

[0047] Figure 29 2 is a diagram illustrating a third example of correction according to the fourth embodiment.

[0048] Figure 30 2 is a diagram illustrating a fourth example of correction according to the fourth embodiment.

[0049] Figure 31 2 is a diagram illustrating a fifth example of correction according to the fourth embodiment.

[0050] Figure 32 2 is a diagram illustrating a sixth example of correction according to the fourth embodiment.

[0051] Figure 33 is a flowchart illustrating an example of a correction value calculation operation of the liquid discharge apparatus according to the fourth embodiment.

[0052] Figure 34 is a flowchart illustrating an example of detailed operation of correction value calculation of the liquid discharge apparatus according to the fourth embodiment. DETAILED DESCRIPTION

[0053] Hereinafter, a mode for carrying out the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, the same constituent elements are denoted by the same reference numerals, and repeated explanation thereof will be omitted as appropriate.

[0054] In addition, the embodiments described below are examples of liquid discharge devices for embodying the technical concepts of the present invention, and the present invention is not limited to the embodiments described below. Unless otherwise specified, the dimensions, materials, shapes, relative arrangements, parameter values, etc. of the constituent elements described below are not intended to limit the subject matter of the present invention to only those described below, but are intended to illustrate examples. In addition, the dimensions and arrangements of the components shown in the drawings may be exaggerated to clarify the explanation. It should be noted that the terms "printing" and "image formation" used in the embodiments are considered synonymous.

[0055] In this embodiment, first image data is acquired, and second image data is generated by adding a predetermined pattern to the first image data. Then, third image data is generated by correcting the first image data for each page based on both the second image data and the read image data of an image formed on a recording medium based on the second image data. Liquid is discharged onto the recording medium based on the third image data. Liquid is discharged onto the recording medium based on the third image data, which has been corrected according to the amount of deformation of the recording medium for each image. This ensures accurate image correction even when the images formed on the recording medium differ in the amount of deformation of the recording medium.

[0056] Hereinafter, the embodiment is described while assuming that ink is an example of liquid and paper is an example of recording medium. In the embodiment, a "graphic" is referred to as a "mark."

[0057] <First embodiment>

[0058] <Example of Overall Configuration of Liquid Discharge Device 1>

[0059] First, refer to Figure 1 The overall configuration of the liquid discharge device 1 is explained. Figure 1 1 is a block diagram showing an example of the overall configuration of the liquid discharge device 1. Figure 1 As shown, the liquid discharge apparatus 1 includes a digital front end (DFE) 2 , an image processing unit 3 , and a printer 4 configured to be capable of transmitting and receiving data or signals to and from each other.

[0060] The liquid discharge device 1 receives a print job from a personal computer (PC) 5 (i.e., an external device), forms an image on a sheet based on the print job, and outputs a printed product 6 consisting of the sheet on which the image is formed. The sheet is a sheet member such as plain paper or coated paper. However, the recording medium is not limited to a sheet and may be a sheet member such as an OHP (overhead projector) sheet or film. The sheet member is preferably a cut sheet cut to a predetermined size, but may be a continuous form paper that is not cut.

[0061] The DFE 2 generates raster image data (ie, an example of first image data) using a raster image processor (RIP) engine based on a print job received from the PC 5 , and outputs the raster image data to the image processing unit 3 .

[0062] Furthermore, the DFE 2 receives correction values ​​for correcting an image to be formed on a sheet from the image processing unit 3 and stores the correction values. The DFE 2 may output the correction values ​​to the image processing unit 3 together with the raster image data.

[0063] The image processing unit 3 is an example of an image processing device for performing processing for correcting an image to be formed on a sheet. The image processing unit 3 generates raster image data (an example of second image data) obtained by adding a predetermined mark to the raster image data received from the DFE 2. In addition, the image processing unit 3 obtains read image data from the printer 4, which is read by a sensor provided in the printer 4.

[0064] The image processing unit 3 calculates a correction value based on the amount of sheet deformation obtained from the marked raster image data and the read image data. The image processing unit 3 then corrects the raster image data or the marked raster image data based on the correction value and generates corrected raster image data or marked raster image data (an example of third image data). In the following explanation, for simplicity, either the corrected raster image data or the marked raster image data is simply referred to as correction data. Either the marked raster image data or the correction data is output to the printer 4.

[0065] The printer 4 discharges ink based on either the mark-added raster image data or the correction data received from the image processing unit 3 to form an image on a sheet.

[0066] In the above explanation, an example has been explained in which the image processing unit 3 corrects the raster image data generated by the DFE 2. However, the image processing unit 3 may be configured to correct the image data included in the print job before the raster image data is generated by the DFE 2. Specifically, the image processing unit 3 may correct the RGB image data composed of R (red), G (green), and B (blue) included in the print job before converting it into CMYK image data composed of C (cyan), M (magenta), Y (yellow), and K (black). In this case, the RGB image data included in the print job corresponds to an example of the first image data.

[0067] <Example of Configuration of Printer 4>

[0068] Next, refer to Figure 2 The configuration of the printer 4 included in the liquid discharge apparatus 1 is explained. Figure 2 4 is a diagram for explaining an example of the configuration of the printer 4 .

[0069] like Figure 2As shown, the printer 4 includes a feeding unit 41, a printing unit 42, a drying unit 43, a cooling unit 44, and a conveying unit 45. An arrow extending through these units (i.e., an arrow starting from the feeding unit 41, passing through the printing unit 42, the drying unit 43, and the cooling unit 44, bending back in the conveying unit 45, passing through the printing unit 42 again, and returning to the feeding unit 41) indicates a conveying path P along which a sheet is conveyed in the printer 4.

[0070] In the printer 4, the printing unit 42 forms an image on the front surface (i.e., first surface) of a sheet supplied from the supply unit 41 using ink for forming an image. The drying unit 43 then dries the ink adhered to the sheet, and the sheet is then discharged from the sheet discharge tray 451 of the transport unit 45. In the case of duplex printing, in which images are formed on both the front and back surfaces of the sheet, the duplex unit 452 switches back to the sheet, and the printing unit 42 again forms an image on the back surface (i.e., second surface) on the opposite side of the sheet's front surface. The sheet then passes through the drying unit 43, the cooling unit 44, and the transport unit 45, and is then discharged from the sheet discharge tray 451 or the sheet discharge tray 412.

[0071] (Supply unit 41)

[0072] The feeding unit 41 includes a sheet feeding tray 411 on which a plurality of sheets are stacked, and a sheet discharge tray 412 on which sheets having images formed on their rear surfaces are sequentially stacked and stored. Sheets are separated one by one and fed from the sheet feeding tray 411 by a feeding device (not shown) and fed to the printing unit 42. The feeding unit 41 is not particularly limited in its configuration as long as it feeds sheets to the printing unit 42.

[0073] (Printing unit 42)

[0074] The printing unit 42 includes a receiving body 421 for receiving a supplied sheet, a conveying roller 422 for carrying and conveying the sheet on its outer peripheral surface, and an ink discharge unit 423 for discharging ink from a nozzle toward the sheet carried on the conveying roller 422. Furthermore, the printing unit 42 includes a supply body 424 for supplying the sheet conveyed by the conveying roller 422 to the drying unit 43, and a sensor 425 for reading an image formed on the sheet.

[0075] The sheet conveyed from the feeding unit 41 to the printing unit 42 is conveyed according to the movement of the surface of the receiving body 421, wherein the end of the sheet is gripped by a sheet gripper provided on the surface of the receiving body 421. The sheet conveyed by the receiving body 421 is delivered to the conveying roller 422 at a position facing the conveying roller 422.

[0076] A sheet gripper is also provided on the surface of the conveyor roller 422, and the end of the sheet is gripped by the sheet gripper. The surface of the conveyor roller 422 is formed with a plurality of suction holes in a dispersed manner, and a suction device generates a suction air flow into the inside of the conveyor roller 422 through each suction hole. The sheet supplied from the receiving body 421 to the conveyor roller 422 has its end gripped by the sheet gripper and is drawn to the surface of the conveyor roller 422 by the suction air flow, so that the sheet is conveyed according to the movement of the surface of the conveyor roller 422.

[0077] The ink discharge unit 423 is an example of a liquid discharge unit that discharges four colors of ink (i.e., K, C, M, and Y) from a nozzle onto a sheet based on either the raster image data or the correction data for the additional mark. The ink discharged by the ink discharge unit 423 forms an image on the sheet. The ink discharge unit 423 includes corresponding ink ejectors for the corresponding colors of ink. The configuration of the corresponding ink ejectors for the corresponding colors is not particularly limited and can be any configuration as long as the corresponding ink ejectors for the corresponding colors discharge ink.

[0078] In this embodiment, the ink colors are four colors, namely K, C, M, and Y, but the present invention is not limited thereto. If necessary, an ink ejector for ejecting ink of a special color (such as white, gold, silver, etc.) may be provided, and an ink ejector for ejecting ink that does not constitute an image (such as a surface coating liquid) may also be provided.

[0079] The ink ejection operation of the corresponding ink ejectors of the ink ejection unit 423 is controlled by a drive signal based on either the raster image data or the correction data of the additional mark. When a sheet carried on the transport roller 422 passes through an area facing the ink ejection unit 423, ink of the corresponding color is ejected from the nozzles included in the ink ejector of the corresponding color, thereby adhering to the sheet, thereby forming an image based on either the raster image data or the correction data of the additional mark. The configuration of the printing unit 42 is not particularly limited, as long as the printing unit 42 forms an image by causing ink to adhere to the sheet.

[0080] The sensor 425 is an example of a reading unit provided in the printing unit 42 to read an image formed on a sheet. The image read by the sensor 425 is an image formed on the sheet based on the raster image data to which a predetermined mark is added. The sensor 425 outputs the read image data (i.e., the result obtained by reading the image) to the image processing unit 3 (see Figure 1 ).

[0081] Sensor 425 is a charge-coupled device (CCD) line sensor, in which pixels that output electrical signals based on the intensity of received light are arranged in a one-dimensional array. The pixels are arranged in a direction that intersects the direction in which the sheet is conveyed (i.e., the longitudinal direction of the paper surface). Sensor 425 includes a pixel array that receives red light (R), a pixel array that receives green light (G), and a pixel array that receives blue light (B).

[0082] In the case of a pixel array of corresponding colors, the sensor 425 outputs an electric signal according to the light intensity of the reflected light reflected by the image formed on the sheet. Using the output of the sensor 425, the image formed on the sheet is read.

[0083] Sensor 425 may be provided with a light source for illuminating the sheet with light. By illuminating the sheet with light from the light source, sufficient brightness for reading with sensor 425 can be ensured. Furthermore, sensor 425 may be configured with a complementary metal oxide semiconductor (CMOS), a photodiode (PD) array, or the like, instead of a charge coupled device (CCD). The configuration of sensor 425 is not particularly limited, as long as sensor 425 reads an image formed on the sheet.

[0084] (Drying unit 43)

[0085] The drying unit 43 dries the ink that has been adhered to the sheet by the printing unit 42. The sheet conveyed from the printing unit 42 is dried by the drying unit 43 using heat, and then conveyed to the cooling unit 44. The drying process applied to the ink on the sheet evaporates the liquid (such as water) in the ink, fixing the ink on the sheet and reducing curling of the sheet. The configuration of the drying unit 43 is not particularly limited, as long as the drying unit 43 dries the ink on the sheet.

[0086] (Cooling unit 44)

[0087] The cooling unit 44 cools the sheet heated by the drying unit 43. The cooling unit 44 cools the sheet by blowing air toward the sheet with a fan or by bringing the sheet into contact with the surface of a cooling conveyor roller. The configuration of the cooling unit 44 is not particularly limited as long as the cooling unit 44 cools the sheet.

[0088] (Transmission unit 45)

[0089] The conveying unit 45 includes: a sheet discharge tray 451 on which sheets conveyed from the cooling unit 44 are sequentially stacked and stored; and a duplex unit 452 that performs duplex conveying processing of the sheet by reversing the sheet having an image formed thereon by the printing unit 42 and feeding the sheet back to the image forming unit 200 to perform duplex printing on the sheet.

[0090] (Other functional units)

[0091] As described above, the printer 4 includes a supply unit 41, a printing unit 42, a drying unit 43, a cooling unit 44, and a conveying unit 45, but may also include other functional units as needed. For example, a preprocessing unit that performs preprocessing of image formation may be added between the supply unit 41 and the printing unit 42, and a postprocessing unit that performs postprocessing of image formation may be added between the cooling unit 44 and the conveying unit 45.

[0092] Examples of the preprocessing unit include a unit that performs a processing liquid application process for applying a processing liquid to the sheet to reduce ink bleeding caused by reaction with the ink, but the content of the preprocessing is not particularly limited. In addition, examples of the postprocessing unit include a unit that performs a process for binding a plurality of sheets on which images are formed, but the content of the postprocessing is also not particularly limited.

[0093] The liquid discharge device 1 is a device that performs printing by relatively moving an ink discharge head and a sheet material, but is not limited thereto. Alternatively, the liquid discharge device 1 may be a serial type device that moves the ink discharge head, a line type device that does not move the ink discharge head, etc.

[0094] The "ink discharge head" is a functional component that discharges and ejects ink from ink discharge holes (nozzles). As an energy source for discharging ink, it is possible to use a discharge energy generating device such as a piezoelectric actuator (laminated piezoelectric element and thin film piezoelectric element), a thermal actuator using an electrothermal conversion element such as a heating resistor, and an electrostatic actuator composed of a vibration plate and a counter electrode, but the discharge energy generating device used by the "ink discharge head" is not particularly limited.

[0095] <Example of the hardware configuration of DFE 2>

[0096] Next, refer to Figure 3 Explain the hardware configuration of DFE 2. Figure 3 is a block diagram for explaining an example of the hardware configuration of DFE 2.

[0097] As Figure 3As shown, the DFE 2 includes a central processing unit (CPU) 21, a read-only memory (ROM) 22, a random access memory (RAM) 23, a solid-state drive (SSD) 24, a hard disk drive (HDD) 25, a graphics processing unit (GPU) 26, an interface (I / F) 27, a liquid crystal display (LCD) 28, and an operation unit 29, which are connected so as to be able to send and receive signals or data to and from each other via a system bus B1.

[0098] Among them, the CPU 21 controls the overall operation of the DFE 2. The ROM 22 stores programs such as an initial program loader (IPL) for driving the CPU 21. The RAM 23 is used as a work area for the CPU 21.

[0099] The SSD 24 and the HDD 25 store various data such as programs. The GPU 26 is a processor that performs calculation processing required for image rendering.

[0100] The interface 27 is an interface for connecting various external devices. In this case, the external devices are the image processing unit 3 and the printer 4. The interface 27 may also include a network interface function for performing data communication using a network.

[0101] The LCD 28 is a display device that displays various information such as a cursor, menus, windows, characters, images, and the like. The operation unit 29 includes input devices such as a keyboard provided with a plurality of keys for inputting characters, numerical values, various instructions, and the like; a pointing device for selecting and executing various instructions, selecting a processing target, moving a cursor, and the like; a touch panel display implemented with the LCD 28; and the like. The operation unit 29 is a unit for operating the DFE 2.

[0102] <Example of Hardware Configuration of Image Processing Unit 3>

[0103] Next, refer to Figure 4 The hardware configuration of the image processing unit 3 is explained. Figure 4 2 is a block diagram for explaining the hardware configuration of the image processing unit 3 .

[0104] like Figure 4 As shown, the image processing unit 3 includes a CPU 31, a ROM 32, a RAM 33, an SSD 34, an HDD 35, a GPU 36, an application-specific integrated circuit (ASIC) 37, a field programmable gate array (FPGA) 38, and an interface 39, which are connected so as to be able to send and receive signals or data to and from each other via a system bus B2.

[0105] Among them, the CPU 31 controls the overall operation of the image processing unit 3. The ROM 32 stores programs for driving the CPU 31, such as the IPL. The RAM 33 serves as the working area of the CPU 31. The SSD 34 and HDD 35 store various data such as programs. The GPU 36 is a processor that performs the computational processing required for image rendering.

[0106] The ASIC 37 is an integrated circuit that integrates circuits for multiple functions implemented by the image processing unit 3. The FPGA 37 is an integrated circuit that integrates circuits for multiple functions implemented by the image processing unit 3. The FPGA 37 can set or change the functions to be implemented after manufacturing the integrated circuit.

[0107] The interface 39 is an interface for connecting various external devices. In this case, the external devices are the DFE 2, the printer 4, etc. The interface 39 may also include a network interface function for data communication using a network.

[0108] <Examples of the functional configurations of the DFE 2 and the image processing unit 3>

[0109] Next, refer to Figure 5 to explain the functional configurations of the DFE 2 and the image processing unit 3. Figure 5 is a block diagram for explaining the functional configurations of the DFE 2 and the image processing unit 3.

[0110] As Figure 5 shown, the image processing unit 3 includes a first image acquisition unit 301, a second image generation unit 302, a read image acquisition unit 303, a deformation amount detection unit 304, a correction value acquisition unit 305, and a correction unit 306. These functions are implemented by the CPU 31 executing a predetermined program or by the ASIC 37, FPGA 38, etc.

[0111] The first image acquisition unit 301 receives and acquires raster image data from the DFE 2. The acquired raster image data is output to the second image generation unit 302.

[0112] The second image generation unit 302 generates raster image data with an additional mark obtained by adding a prediction mark to the raster image data received from the first image acquisition unit 301. The second image generation unit 302 outputs the generated raster image data with the attached mark to the deformation amount detection unit 304 or the printer 4.

[0113] For example, when the image correction according to the embodiment is not performed, the second image generation unit 302 outputs the marked raster image data to the printer 4. When the image correction according to the embodiment is performed, the second image generation unit 302 outputs the marked raster image data to the deformation amount detection unit 304.

[0114] The read image acquisition unit 303 receives and acquires, from the sensor 425 , read image data read from an image formed on a sheet by the sensor 425 based on the raster image data of the attached mark.

[0115] The deformation amount detection unit 304 detects the deformation amount of the sheet by calculation based on the marked raster image data and the read image data.

[0116] In this case, the amount of ink attached to the sheet differs depending on the area size or density of the image formed on the sheet. Depending on the amount of ink that has adhered to the sheet, the amount of deformation (expansion and contraction) of the sheet due to heating by the drying unit 43 or cooling by the cooling unit 44 may differ. The deformation amount detection unit 304 calculates the difference in position, size, etc. between the mark in the raster image data of the attached mark and the mark in the read image data, and the deformation amount detection unit 304 can detect the deformation amount of the sheet based on the difference. Reference Figure 17 These tags are interpreted individually.

[0117] Sensor 425 reads an image as RGB image data, but the read image data can be converted into CMYK image data to facilitate comparison with the raster image data of the attached mark (i.e., CMYK image data). This conversion can be performed by sensor 425 or read image acquisition unit 303. However, even if the read image data is RGB image data and the raster image data of the attached mark is CMYK image data, the amount of deformation can be detected because the difference in the position, size, etc. of the mark can be calculated. In the case where RGB image data before conversion to CMYK image data by DFE 2 is used as the first image data, the first image data and the read image data can be compared as RGB image data to detect the amount of deformation. Alternatively, sensor 425 can obtain monochrome image data. In this case, the difference in the position, size, etc. of the mark can be calculated based on the monochrome image data.

[0118] The correction value obtaining unit 305 obtains a correction value through calculation based on the deformation amount of the sheet detected by the deformation amount detecting unit 304. The correction value is output to the DFE 2.

[0119] In this case, the DFE 2 includes a correction value storage unit 21. The function of the correction value storage unit 21 is as follows: Figure 3The correction value storage unit 21 can receive and store the correction value acquisition unit 305 of the image processing unit 3.

[0120] The correction unit 306 obtains the correction value obtained by the correction value obtaining unit 305 by referring to the correction value storage unit 21 of the DFE 2, and generates correction data by correcting the raster image data or the marked raster image data based on the correction value. The DFE 2 outputs the correction data to the printer 4. In this embodiment, for example, the configuration in which the correction value storage unit 21 is provided in the DFE 2 is explained, but this embodiment is not limited to this. For example, the image processing unit 3 may have the function of the correction value storage unit 21, and an external device may have the function of the correction value storage unit 21.

[0121] The ink discharge unit 423 of the printer 4 (see Figure 2 ) forms an image by discharging ink onto a sheet based on either the mark-added raster image data received from the second image generation unit 302 or the correction data received from the correction unit 306. For example, when correction according to this embodiment is not performed, the ink discharging unit 423 discharges ink based on the mark-added raster image data. In contrast, when image correction according to this embodiment is performed, the ink discharging unit 423 discharges ink based on the correction data.

[0122] One or more functions of the image processing unit 3 explained above may be provided in the DFE 2 or the printer 4. Alternatively, one or more functions of the image processing unit 3 may be provided in the DFE 2 and the printer 4 in a distributed manner.

[0123] <Operation Example of Liquid Discharge Device 1>

[0124] Next, refer to Figures 6 to 8 The operation of the liquid discharge device 1 is explained.

[0125] (Example of overall configuration)

[0126] Figure 6 is a flowchart for explaining an example of the overall operation of the liquid discharge apparatus 1 .

[0127] First, in step S61 , the liquid discharge apparatus 1 obtains a correction value through calculation and stores the obtained correction value in the DFE 2 .

[0128] Next, in step S62 , the liquid discharge apparatus 1 performs correction image forming processing using the obtained correction value.

[0129] In this manner, the liquid discharge apparatus 1 can form an image corrected using the previously obtained correction value on a sheet.

[0130] (Example of Correction Value Obtaining Operation)

[0131] Next, Figure 7 1 is a flowchart for explaining an example of the correction value obtaining operation of the liquid discharge device 1. Figure 7 In the Figure 6 The operation of step S61 in the entire operation shown.

[0132] First, in step S71, the first image obtaining unit 301 of the image processing unit 3 obtains raster image data by receiving the raster image data from the DFE 2. The obtained raster image data is output to the second image generating unit 302.

[0133] Next, in step S72, the second image generation unit 302 generates marked-added raster image data obtained by adding a predetermined mark to the raster image data received from the first image acquisition unit 301. The second image generation unit 302 outputs the generated marked-added raster image data to the printer 4.

[0134] Next, in step S73 , the ink discharge unit 423 of the printer 4 discharges ink toward the sheet based on the mark-added raster image data received from the second image generation unit 302 to form an image on the sheet.

[0135] Next, in step S74 , the sensor 425 of the printer 4 reads the image formed on the sheet based on the raster image data of the added mark, and outputs the image to the read image obtaining unit 303 .

[0136] Next, in step S75 , the deformation amount detection unit 304 detects the deformation amount of the sheet by calculation based on the marked raster image data and the read image data received via the read image obtaining unit 303 .

[0137] Next, in step S76 , the correction value obtaining unit 305 obtains a correction value through calculation based on the deformation amount of the sheet detected by the deformation amount detecting unit 304 , and outputs the obtained correction value to the DFE 2 .

[0138] Next, in step S77 , the correction value storage unit 21 of the DFE 2 stores the correction value received from the correction value obtaining unit 305 .

[0139] In this manner, the liquid discharge device 1 can obtain and store the correction value.

[0140] (Example of Correction Image Forming Operation)

[0141] Next, Figure 81 is a flowchart for explaining an example of the correction image forming operation of the liquid discharge device 1. Figure 8 In the Figure 6 The operation of step S62 in the entire operation shown.

[0142] exist Figure 8 In this embodiment, the term "page" is used. In this embodiment, a page refers to a single surface of a sheet. When printing multiple sheets using single-sided printing to form an image on a single surface of each sheet, "first page" refers to the front surface of the first sheet of the multiple sheets. When printing a single sheet using double-sided printing to form images on both surfaces of the sheet, "first page" refers to the front surface of the sheet. When printing multiple sheets using double-sided printing, "first page" refers to the front surface of the first sheet of the multiple sheets.

[0143] However, the term "subsequent page" refers to a page having an image formed thereon subsequently in the image formation order. The order of image formation changes due to interleaf duplex printing, and therefore, a "subsequent page" is not always the subsequent page in a print job. Interleaf duplex printing is an imaging method in which image formation on a subsequent sheet begins in the period between imaging on the front surface and imaging on the rear surface of the sheet immediately preceding the subsequent sheet.

[0144] exist Figure 8 In step S81, first, the DFE 2 outputs to the image processing unit 3 (i) correction values ​​corresponding to raster image data based on which an image is to be formed on a first page of a sheet, and (ii) raster image data corresponding to the correction values.

[0145] Next, in step S82 , the correction unit 306 of the image processing unit 3 receives the correction value and the raster image data from the DFE 2 and corrects the raster image data based on the correction value. The correction data is output to the printer 4 .

[0146] Next, in step S83 , the printer 4 forms an image on a sheet based on the correction data.

[0147] Next, in step S84 , the DFE 2 determines whether to end image formation.

[0148] If, in step S84, image formation is determined to be completed (step S84: Yes), the operation is terminated. In contrast, if image formation is determined not to be completed (step S84: No), in step S85, the DFE 2 outputs the correction values ​​for the "subsequent page" and the raster image data corresponding to the correction values ​​to the image processing unit 3. The process then returns to step S82, and the processing in step S82 and subsequent steps is repeated.

[0149] In this manner, the liquid discharge apparatus 1 can perform correction image formation using the previously obtained correction value.

[0150] The liquid discharge device 1 can be executed before production printing Figure 7 The correction value acquisition operation is performed as a test print, and can be performed Figure 8 The correction image forming operation is performed as a production print of the print job, for which Figure 7 In this case, test printing is printing for forming an image on a recording medium that is not used as a print product, and test printing corresponds to trial printing. In contrast, production printing is printing for forming an image on a recording medium that is used as a print product.

[0151] A correction value for each page is obtained by using (i) an image formation result generated by a test print of a print job specified by a user and (ii) read image data of a sheet, and when production printing of the same print job is performed, correction image formation is performed by using the saved correction value for each of all pages. Hereinafter, correction image formation may be simply referred to as correction.

[0152] Regarding the correction value for each page, for a print job that prints on one side, the correction value is obtained for the single surface on which the image is formed. For a print job that prints on both sides, the correction values ​​are obtained for the front and rear surfaces of the page on which the images are formed. The correction method and test print are set on the job settings screen used to configure the settings for each print job. In this case, the front surface is an example of the first surface, and the rear surface is an example of the second surface.

[0153] <Example of calibration value acquisition operation using test print>

[0154] (Overall operation)

[0155] The liquid discharge device 1 can perform test printing before production printing of each print job and obtain correction values ​​for each page. The liquid discharge device 1 obtains the correction values ​​and thereafter performs production printing by selecting the print job for which the test printing has been completed, so that the liquid discharge device 1 can form an image whose position on the corresponding page has been corrected by the correction values ​​obtained from the test printing.

[0156] In response to a user instruction on the operation screen of the DFE 2 , the liquid discharge apparatus 1 performs test printing of a print job and production printing of a print job at different points in time.

[0157] The liquid discharge apparatus 1 performs test printing in response to an execution instruction on an operation screen for configuring image position correction in a job setting screen for configuring settings of a print job selected from a list screen of print jobs received by the DFE 2.

[0158] In the print job settings, users can also configure settings for image position correction of the print job, settings for selecting single-sided printing or double-sided printing as the printing conditions for the print job, settings for the print mode (productivity, image quality), settings for the type of recording medium, settings for pre-application conditions (whether to perform pre-treatment liquid application), etc.

[0159] The setting of image position correction for correcting the image position of a print job is provided with a predetermined user interface (UI). The liquid discharge apparatus 1 displays the UI on a screen of the DFE 2, a PC (ie, a user terminal), the printer 4, or the like.

[0160] In the image position correction settings, you can set "Correction On," select the correction type, and "Correction Off." With "Correction On," image position correction using test printing is enabled. The liquid ejection device 1 obtains correction values ​​by performing test printing according to the configuration conditions. The DFE 2 of the liquid ejection device 1 associates the obtained correction values ​​with the identification information of the corresponding page.

[0161] The liquid discharge device 1 performs test printing for each print job. When correction values ​​are recorded once for each print job, the liquid discharge device 1 can perform correction using the correction values ​​associated with the print job when the print job is executed again, as long as the image position correction settings remain unchanged. Note that even if the DFE 2 receives print jobs for the same file, if the DFE 2 receives the print jobs at different times, the print jobs are considered different.

[0162] The DFE 2 associates and stores a single image position correction setting and correction value with any given print job. This is because the expansion and contraction rates of recording media during image formation vary depending on the combination of image position correction settings (e.g., whether the settings are configured for high-quality printing with preprocessing or high-productivity printing without preprocessing). If the print job settings change, the DFE 2 records the image position correction settings as another print job. Furthermore, the DFE 2 can associate and display multiple combinations of image position correction and correction value settings with any given print job.

[0163] The liquid discharge device 1 performs production printing using correction values ​​from a test print saved via a screen for executing a print job using the DFE 2. In the data saved by the DFE 2, print job identification information, page identification information, and correction (or correction value) identification information are associated with each other. During image formation, the DFE 2 transmits the associated correction values ​​to the image processing unit 3.

[0164] (Settings screen example)

[0165] refer to Figures 9 to 12 The screen transition from the list screen of print jobs to the print job setting screen of the DFE 2 is explained. Figure 9 is a drawing showing an example of a list screen of print jobs. Figures 10 to 12 is a drawing showing an example of the setting of the image position correction screen. Figure 10 A first example is shown, Figure 11 A second example is shown, and Figure 12 A third example is shown.

[0166] When the DFE 2 receives the print job, the liquid discharge device 1 causes the DFE 2 to display the following information on the LCD 28: Figure 9 The job list screen 501 is shown. The user selects a plurality of print jobs displayed as a list on the operation screen of the DFE 2 to configure print job settings. The print job settings include not only settings for image position correction but also various settings such as settings for selecting whether to print on one side or on both sides and settings for the color material to be used.

[0167] The user can instruct execution of image formation by touching the job execution button 502, and can cause the operation screen to transition to the print job setting screen by touching the job setting button 503. In addition, the user can delete a print job by touching the job delete button 504, and can acquire data of a new print job by touching the job add button 505.

[0168] When the job setting button 503 is touched, a property screen 510 for displaying various setting buttons for the print job is opened. The user touches the setting of the image position correction button 511 from among the multiple items displayed on the property screen 510 so that the settings such as the following can be displayed. Figures 10 to 12 Image position correction setting screen 520 is shown.

[0169] Image Position Correction Settings screen 520 includes a pull-down Image Position Correction button 521 and a test print selection checkbox 522 for obtaining correction values ​​for each page. Image Position Correction button 521 allows the user to select "Off," "Per Page," or "Per Medium" regarding image position correction. "Per Page" allows the user to store and change correction values ​​on a page-by-page basis. "Per Medium" allows the user to change correction values ​​for each sheet type or each type of recording medium.

[0170] Figure 10 The case where "OFF" is selected using the image position correction button 521 is shown, and Figure 11 A case where “for each page” is selected using the image position correction button 521 is shown.

[0171] When the test print selection checkbox 522 is checked, test printing is performed, and the correction values ​​for each page are associated with the print job in question and saved in the DFE 2. After the test print selection checkbox 522 is checked, only the test print is performed before production printing. Production printing can be configured to be automatically performed in a continuous manner after the test print. In addition, after the test print is performed, the image position correction button 521 can be used to select "For Each Page".

[0172] Examples of scenarios where the user selects a correction method include: selecting "For Each Page" when the expansion and contraction rate varies depending on the type of recording medium, sheet type, etc.; and executing a print job that includes image formation on multiple recording media with different expansion and contraction rates. In this case, test printing does not need to be performed for each page.

[0173] In usage scenarios, such as when it is desired to accurately perform correction for each page, or when performing a print job for performing image formation on a recording medium having greatly different expansion and contraction rates for corresponding pages, correction "for each page" is preferably selected. In addition, in the case where it is desired to more accurately correct the arrangement of the front and rear sides of a postcard or the like, it is preferable to select the most appropriate item from the items displayed in the front and rear side position adjustment box 523. "Front and rear side position adjustment" refers to real-time front and rear side positioning processing (which is referred to as real-time front and rear side positioning) performed in real time during image formation by the liquid discharge device 1. Front and rear side position adjustment can be selected only in the case of double-sided printing. In the case where "sheet edge" or "detection mark" is selected in the front and rear side position adjustment box 523, correction is performed so as to position the rear surface based on the front surface. The sheet edge corresponds to the edge of the recording medium, and the detection mark corresponds to the mark in the raster image data of the additional mark.

[0174] When "Detection Mark" is selected in the image position correction settings and margins or no cutting is set in the print job settings, a conflict indication can be displayed. A conflict indication is an indication that notifies you of conflicting or overlapping settings.

[0175] In the case where “for each page” or “for each medium” is selected with the image position correction button 521 , the number of copies button 524 and the items in the front and rear side position adjustment box 523 become selectable.

[0176] When the number of copies is changed using the copy number button, the DFE 2 calculates the average value of the coordinates of the four detection marks on the corresponding pages of the multiple copies consisting of the multiple recording media. The DFE 2 can also store the correction values ​​of the corresponding pages of the multiple copies and apply the stored correction values ​​to the correction.

[0177] In a print job where test printing is performed once, DFE 2 displays the characters "ADJUSTED" to indicate that correction values ​​for each page have been obtained for the print job. If the same job is selected and executed again later, DFE 2 can apply the correction values ​​associated with the print job.

[0178] When “OFF” is selected with the image position correction button 521 and either “Sheet Edge” or “Detection Mark” is selected among the items in the front and rear side position adjustment frame 523, the DFE 2 determines that the settings are conflicting, and displays the following information: Figure 12 Conflicts screen 530 is shown for resolving conflicts.

[0179] (Details of the operation)

[0180] An explanation is given of an operation for obtaining a correction value using a test print by the liquid discharge apparatus 1. In the test print of double-sided printing, the liquid discharge apparatus 1 performs the following operations (1) to (4) in this order.

[0181] (1) Forming an image on the front surface of a recording medium

[0182] The liquid discharge device 1 forms an image by adding a mark on the front surface. In this case, the liquid discharge device 1 does not perform position correction processing of the image. The mark is added at a position 3 mm away from the edge of the sheet.

[0183] (2) Read the front surface of the recording medium to obtain the correction value

[0184] The liquid discharge device 1 uses the sensor 425 to read the front surface of the recording medium, and the DFE 2 stores the coordinates of the four marks on each page (x0y0, x1y1, x2y2, x3y3). When detecting the coordinates of the marks, the DFE 2 detects the center of gravity of the corner portion of each of the four marks. The DFE 2 searches for the center point of the edge where the mark changes from black to white and adopts the found center point as the center of gravity. Even when obtaining a correction value from the rear surface of the recording medium, the DFE 2 performs similar processing. Therefore, the DFE 2 can obtain the amount of deviation on the front surface (including image distortion and position shift) without correction. In this case, the deviation is caused by, for example, the expansion and contraction of the recording medium due to the ink application and drying. The DFE 2 applies the deviation amount based on the coordinates of the four marks to the rear surface as a correction value.

[0185] In this case, the raster image data of the front surface is not compared with the read result. Only the positional information of the mark on the front surface of the read result is transmitted to the DFE 2, and this is reflected on the rear surface to form an image there. When the positional information is applied to the rear surface, the printer 4 changes the correction values ​​and coordinates. The printer 4 derives the correction values ​​using coordinates that are inverted from top to bottom and from left to right. The printer 4 inverts the coordinates of the mark and retains the inverted coordinates. The uninverted coordinates are used for single-sided printing.

[0186] (3) Forming an image on the rear surface of the recording medium

[0187] After adding the markers and performing the correction process (distortion correction and positional shift correction) based on the front surface based on the deviation from the coordinates of the markers on the front surface of the recording medium, the liquid discharge device 1 forms an image on the rear surface of the recording medium. This is because when the markers are added after the correction is performed, rather than performing the correction after the markers are added, the markers are added to the original position without distortion, and therefore, it is impossible to find the amount of distortion.

[0188] (4) Read the back surface of the recording medium to obtain the correction value

[0189] In the liquid discharge device 1, the sensor 425 reads the rear surface of the recording medium, and the DFE 2 compares the rear surface reading result with the raster image data of the front surface of the recording medium to obtain a correction value for the front surface. Furthermore, the DFE 2 of the liquid discharge device 1 compares the rear surface reading result with the front surface reading result to obtain a correction value for the rear surface. This allows the detection of rear surface deviation (including image distortion and positional shift). In this case, this deviation is caused by, for example, expansion and contraction of the recording medium due to the application of ink twice and the drying of the ink twice.

[0190] When obtaining the correction value for the rear surface, correction based on the front surface has already been performed, and therefore, even if the detected deviation amount is the deviation amount for the rear surface, it also includes the deviation amount for the front surface. DFE 2 obtains the coordinates of the four detection marks as the correction values ​​for the front surface of the same recording medium as the recording medium whose rear surface has been read. DFE 2 obtains the coordinates of the four detection marks as the correction values ​​for the rear surface a second time. When test printing is performed on multiple copies, DFE 2 calculates the average value of the coordinates of the four detection marks on the corresponding pages of the multiple copies. For example, when test printing is performed on three copies, DFE 2 calculates and stores the average value of the coordinates of the marks on three sheets for each of the four marks: the front of P1 for the first copy, the front of P1 for the second copy, and the front of P1 for the third copy.

[0191] Regarding the expansion and contraction of the recording medium (caused by ink application or drying) that causes the deviation, the deviation that occurs when reading the front surface in the above-mentioned operation (2) is caused by the ink application being performed once and the drying being performed once. In contrast, the deviation that occurs when reading the rear surface in the above-mentioned operation (4) is caused by the ink application being performed twice and the drying being performed twice, which further changes the expansion and contraction. The correction value for the front surface is obtained from the result of operation (4), and the correction value for the rear surface is obtained from the results of operation (2) and operation (4). The correction values ​​used in production printing are the coordinates of the positions of the marks on the front and rear sides obtained in operation (4).

[0192] The DFE 2 stores the coordinates of the position of the mark and transmits the coordinates of the position to the image processing unit 3, which determines a correction value to perform correction. The correction value includes the coordinates of the original position of the mark obtained by reading the image data, a difference value calculated by comparing with the original data, an average value obtained by averaging the coordinates of the positions on corresponding pages of a plurality of copies, and the like.

[0193] In the test printing of the single-sided printing, the liquid discharge apparatus 1 performs the following operations (a) to (b) in this order.

[0194] (a) Forming an image on the front surface of a recording medium

[0195] The liquid discharge device 1 forms an image by adding a mark to the front surface of the recording medium. In this case, the liquid discharge device 1 does not perform position correction processing of the image. The mark is added at a position 3 mm away from the edge of the sheet.

[0196] (b) Read the front surface of the recording medium to obtain the correction value

[0197] In the liquid discharge device 1, the sensor 425 reads the front surface of the recording medium, and the DFE 2 stores the coordinates of the four marks (x0y0, x1y1, x2y2, x3y3) for each page. The DFE 2 compares the front surface reading results with the raster image data of the front surface to derive the amount of deviation. Thus, the amount of deviation of the uncorrected front surface (including image distortion and positional shift) is detected. In this case, this deviation is caused by, for example, expansion and contraction of the recording medium due to the ink application and drying processes being performed once. The DFE 2 stores correction values ​​for only the front surface for each page, and the liquid discharge device 1 uses these stored correction values ​​for production printing.

[0198] Figure 13 is a flowchart showing an example of a correction value obtaining operation using a test print by the liquid discharge apparatus 1. The liquid discharge apparatus 1 starts the test print in response to an execution instruction for each print job from the user. Figure 13 operation.

[0199] First, in step S131 , the printer 4 of the liquid discharge apparatus 1 determines whether the print job of the test print is single-sided printing.

[0200] In step S131 , in a case where it is determined that the print job of the test print is single-sided printing (step S131 , Yes), in step S132 , the printer 4 of the liquid discharge apparatus 1 forms an image on the front surface of the recording medium to which the mark is added.

[0201] Next, in step S133 , the sensor 425 of the liquid discharge apparatus 1 reads the front surface of the recording medium to which the mark is added.

[0202] Next, in step S134 , the DFE 2 of the liquid discharge apparatus 1 obtains and saves the coordinates of the position of the mark on each page of the front surface from the read image.

[0203] Next, in step S135, the DFE 2 of the liquid discharge device 1 transmits the position information (test print result) stored in the DFE 2 to the printer 4. Then, the printer 4 of the liquid discharge device 1 obtains and stores the difference value obtained by comparing the coordinates of the position of the mark in the read image of the front surface with the coordinates of the position of the mark added to the raster image data before image formation. The difference value between the coordinates of the position of the mark in the read image read from the front surface and the coordinates of the position of the mark added to the raster image data before image formation can be calculated by the DFE 2.

[0204] The operations from step S131 to step S134 are operations performed based on the test printing by the liquid discharge apparatus 1. The operation of step S135 is an operation performed based on the production printing by the liquid discharge apparatus 1.

[0205] In contrast, in a case where it is determined in step S131 that the print job of the test print is not one-sided printing (step S131 , No), in step S136 , the printer 4 of the liquid discharge apparatus 1 forms an image on the front surface of the recording medium to which the mark is added.

[0206] Next, in step S137 , the sensor 425 of the liquid discharge apparatus 1 reads the front surface of the recording medium to which the mark is added.

[0207] Next, in step S138 , the DFE 2 of the liquid discharge apparatus 1 obtains and saves the position coordinates of the mark from the read image read from the corresponding page on the front surface.

[0208] Next, in step S139 , the DFE 2 of the liquid discharge device 1 obtains and stores a difference value obtained by comparing the coordinates of the position of the mark in the read image read from the front surface with the coordinates of the position of the mark added to the raster image data before image formation.

[0209] Next, in step S140 , the printer 4 of the liquid discharge apparatus 1 adds a mark, performs correction using the obtained difference value, and then forms an image on the rear surface of the recording medium.

[0210] Next, in step S141 , the sensor 425 of the liquid discharge apparatus 1 reads the rear surface of the recording medium to which the mark is added.

[0211] Next, in step S142 , the liquid discharge apparatus 1 obtains and saves the coordinates of the position of the mark from the read image read from the corresponding page on the rear surface.

[0212] Next, in step S143, the DFE 2 of the liquid discharge device 1 transmits the positional information (test print result) about the mark on the rear surface stored by the DFE 2 to the printer 4. Then, the printer 4 of the liquid discharge device 1 obtains and stores the difference value obtained by comparing the coordinates of the position of the mark on the read image read from the rear surface with the coordinates of the position of the mark added to the raster image data before image formation. The difference value between the coordinates of the position of the mark on the read image read from the rear surface and the coordinates of the position of the mark in the raster image data before image formation can be calculated by the DFE 2.

[0213] The operations from step S136 to step S142 are operations performed by the liquid discharge apparatus 1 based on the test printing, and the operation of step S143 is an operation performed by the liquid discharge apparatus 1 based on the production printing.

[0214] In this manner, the liquid discharge apparatus 1 can obtain correction values ​​using the test printing.

[0215] Figure 14 : is a diagram showing an example of a combination list in the correction image forming mode. Figure 14 Item (b) shown in corresponds to correction according to the above-described operation (2) and operation (4), which is the operation of the liquid discharge device 1 in the test printing of the double-sided printing. Figure 14 Item (c) shown in is a real-time front and rear side registration mode, and corresponds to an operation for performing correction based on the correction value of the test print of the front surface and based on the (corrected) reading result of the front surface of the production print of the rear surface.

[0216] In the real-time front and rear side positioning of item (c), when the user selects a mark, the DFE 2 notifies the image processing unit 3 of an instruction on where to add the mark. The image processing unit 3 performs image formation control by adding the mark. The image processing unit 3 of the liquid discharge device 1 calculates a correction value based on the reading result of the front surface to correct the rear surface.

[0217] When the correction using the edge of the recording medium is selected in the real-time front and rear side positioning of item (c), the image processing unit 3 corrects the rear surface by reading the edge of the recording medium without adding any mark. In the correction of the edge of the recording medium, the difference between the vertical and horizontal widths of the recording medium used for image formation and the size of the recording medium obtained by reading the read data of the printed front surface is calculated.

[0218] Correction of the rear surface (ie, making the front side and the rear side match each other) includes the following two cases.

[0219] (A) Read the front surface of the production print (i.e., read the mark printed on the front surface of the recording medium or read the edge of the recording medium), and correct the rear surface to match the front surface (real-time front and rear side positioning).

[0220] (B) Execute the above (A) in advance in test printing, and save the correction amount obtained during execution. Perform correction using the saved correction amount. During production printing, there is no need to print the mark.

[0221] In addition, for the correction method of the rear surface, you can choose Figure 14 Methods other than those shown.

[0222] (Correction value)

[0223] A specific example of correction values ​​(coordinates) obtained in test printing is explained. In other words, the correction values ​​obtained in test printing include difference values ​​calculated by comparing the marks formed on the recording medium and the marks in the original raster image data for each page of the print job.

[0224] The correction values ​​include a main scanning position correction value, a sub-scanning position correction value, a main scanning magnification error correction value, a sub-scanning magnification error correction value, a main scanning left deviation correction value, a main scanning right deviation correction value, a sub-scanning top deviation correction value, and a sub-scanning bottom deviation correction value.

[0225] The main scanning position is a position perpendicular to the image transport direction. The sub-scanning position is a position in the image transport direction. The main scanning magnification is the magnification of the image in the main scanning direction. The sub-scanning magnification is the magnification of the image in the sub-scanning direction. The main scanning left deviation correction value, main scanning right deviation correction value, sub-scanning top deviation correction value, and sub-scanning bottom deviation correction value are correction values ​​used to correct image distortion in the upward (top), downward (bottom), left, and right directions.

[0226] (front and rear side positioning)

[0227] Front and rear side registration is performed during production printing of a print job for duplex printing, for which test printing has been completed with the setting of real-time front and rear side registration being on.

[0228] The liquid discharge device 1 forms an image on the front surface of the recording medium while performing correction using the correction value obtained according to the operation (4) of obtaining the correction value using the test print. Thereafter, the sensor 425 reads the front surface of the recording medium. Thereafter, the liquid discharge device 1 forms an image on the rear surface while correcting the image on the rear surface according to the reading result obtained by reading the image formed on the front surface of the production print. In this case, in a manner similar to the operation (3) of obtaining the correction value using the test print, correction is performed when adding a mark so as to detect distortion. Thereafter, the sensor 425 of the liquid discharge device 1 reads the rear surface of the recording medium. However, in this embodiment, even if the read data obtained by reading the rear surface is obtained, the read data is not used for position correction.

[0229] (Example of correction operation for production printing)

[0230] Figure 15 is a flowchart showing an example of an operation of performing correction using a correction value by the liquid discharge apparatus 1 in production printing. The liquid discharge apparatus 1 starts after performing a test print of each print job. Figure 15 operation.

[0231] First, in step S151 , the DFE 2 of the liquid discharge apparatus 1 saves the correction value obtained through test printing.

[0232] Next, in step S152 , the liquid discharge apparatus 1 starts to perform production printing of the print job.

[0233] Next, in step S153 , the liquid discharge apparatus 1 determines whether the correction setting is on.

[0234] If the correction setting is turned on in step S153 (step S153, yes), in step S154, the liquid discharge apparatus 1 performs correction on neither the front surface nor the rear surface, or performs correction by applying a predetermined correction value to all pages. Then, the liquid discharge apparatus 1 ends the operation after the correction is completed.

[0235] In contrast, in step S153 , in a case where it is determined that the setting of correction is not on (step S153 , No), in step S155 , the liquid discharge apparatus 1 determines whether the setting of correction is image position correction for each page.

[0236] In step S155 , in a case where it is determined that the correction setting is page-based image position correction (step S155 , Yes), in step S156 , the liquid discharge apparatus 1 determines whether the real-time front and rear side registration setting is selected.

[0237] If, in step S156, it is determined that the real-time front and rear registration setting is selected (step S156, Yes), in step S157, the liquid discharge device 1 corrects each page using the correction value previously obtained for each page through test printing. The liquid discharge device 1 forms an image on a single surface in the case of single-sided printing, or on both surfaces (i.e., the front and rear surfaces) in the case of double-sided printing, while performing correction for each page using the previously obtained correction value. After image formation is completed, the liquid discharge device 1 ends its operation.

[0238] In contrast, in step S156 , in a case where it is determined that the real-time front and rear side registration setting is not selected (step S156 , No), in step S158 , the liquid discharge apparatus 1 determines whether to perform real-time front and rear side registration using a marker.

[0239] In step S158, if it is determined that real-time front and rear side registration using the mark is performed (step S158, Yes), in step S159, the liquid discharge device 1 performs correction by using the correction value for each page previously obtained by test printing, and thereafter forms an image on the front surface of the recording medium while performing image processing for adding the mark. Thereafter, the liquid discharge device 1 performs correction based on the mark position detection result of the front surface obtained in production printing, and forms an image on the rear surface of the recording medium (real-time front and rear side registration).

[0240] In contrast, in step S158, if it is determined that real-time front and rear side registration using the mark is not being performed (step S158, No), in step S160, the liquid discharge device 1 forms an image on the front surface while performing correction using the correction value for each page previously obtained by test printing. Thereafter, the liquid discharge device 1 forms an image on the rear surface while performing correction based on the detection result obtained from the edge of the recording medium on the front surface of production printing (real-time front and rear side registration).

[0241] Furthermore, if, in step S155, the correction setting is determined not to be page-based image position correction (step S155, No), in step S161, the liquid discharge device 1 performs correction for all pages of the print job using the correction values ​​pre-set according to the type of recording medium. In this case, real-time front and rear side registration is selectable. If real-time front and rear side registration is selected, the image formation on the rear surface is corrected based on the image formation on the front surface. In this case, it is selectable whether to use the mark or the edge of the recording medium.

[0242] In this manner, the liquid discharge apparatus 1 can perform correction processing using the correction value in production printing.

[0243] Figure 16 : is a timing chart showing an example of the correction operation of the liquid discharge apparatus 1 using the correction value.

[0244] exist Figure 16 In the embodiment of the present invention, first, when a print job is sent from the PC 5 to the liquid discharge apparatus 1 in response to a user instruction to turn on the liquid discharge apparatus 1, the DFE 2 of the liquid discharge apparatus 1 generates job identification information in step S171.

[0245] The operations up to step S171 correspond to a test print execution operation and a page-based correction value obtaining operation.

[0246] Next, after the user enters print job settings and correction value settings, an execution instruction for test printing is issued. In response to this execution instruction, the DFE 2 of the liquid discharge device 1 generates page identification information for the print job in step S172 and thereafter begins execution of the test print of the print job. The DFE 2 transmits the raster image data and the page identification information for the print job to the image processing unit 3.

[0247] Next, in step S173 , the image processing unit 3 of the liquid discharge apparatus 1 performs image formation control using the raster image data.

[0248] Next, in step S174 , the printer 4 of the liquid discharge apparatus 1 forms an image based on the raster image data, and the sensor 425 of the liquid discharge apparatus 1 reads the image formed on the recording medium and sends the read data to the image processing unit 3 .

[0249] Next, in step S175 , the image processing unit 3 of the liquid discharge apparatus 1 obtains a correction value using the mark or recording medium edge of each page, and transmits the correction value associated with the page identification information to the DFE 2 .

[0250] Next, in step S176 , the DFE 2 of the liquid discharge apparatus 1 stores the correction value of each piece of page identification information in association with the job identification information.

[0251] The operations from step S172 to step S176 correspond to a test print execution operation and a page-based correction value obtaining operation.

[0252] Thereafter, in response to a user instruction to execute production printing, the DFE 2 transmits the raster image data, page identification information, and correction values ​​associated with the page identification information to the image processing unit 3. The user issues an instruction to execute production printing for a print job for which a test print has been executed and correction values ​​have been obtained. Production printing can be automatically executed after the test print. The user can also issue an instruction to execute production printing when selecting a past print job.

[0253] Next, in step S177 , the image processing unit 3 of the liquid discharge apparatus 1 performs correction for each page based on the raster image data received from the DFE 2 , the page identification information, and the correction value associated with the page identification information.

[0254] Next, in step S178 , the image processing unit 3 of the liquid discharge apparatus 1 performs image formation control using the correction data.

[0255] Next, in step S179 , the printer 4 of the liquid discharge apparatus 1 forms an image based on the correction data, and the sensor 425 of the liquid discharge apparatus 1 reads the image formed on the recording medium and sends the read data to the image processing unit 3 .

[0256] Next, when the real-time front and rear side registration setting is turned on in the correction setting, in step S180 , the image processing unit 3 of the liquid discharge apparatus 1 corrects the raster image data of the rear surface according to the reading result of the front surface of the corresponding page in duplex printing.

[0257] Next, in step S181 , the image processing unit 3 of the liquid discharge apparatus 1 performs image formation control of the rear surface using the correction data.

[0258] Next, in step S182, the printer 4 of the liquid discharge device 1 forms an image based on the correction data, and the sensor 425 of the liquid discharge device 1 reads the image formed on the recording medium and sends the read data to the image processing unit 3. Note that the read data of the rear surface is not used for the correction process according to the present embodiment, but is used for another process such as defect detection.

[0259] The operations from step S177 to step S182 correspond to execution operations of production printing using the correction value for each page.

[0260] In this manner, the liquid discharge apparatus 1 can perform correction using the correction value. Performing correction for each page through test printing and production printing allows an appropriate image to be obtained even when the amount of deformation of the sheet differs from page to page.

[0261] (Application of correction value during duplex printing between pages)

[0262] Hereinafter, a method for determining on which of the front surface or the rear surface an image is formed and applying a stored correction value during inter-page duplex printing is explained.

[0263] The liquid discharge device 1 alternately forms images on the front and back surfaces in the following order, and during inter-page duplex printing, identification information is added to the corresponding pages. The liquid discharge device 1 sorts the correction values ​​by the order in which the images are formed, and the DFE 2 stores the sorted correction values. Hereinafter, for example, "front 1" refers to page 1 on the front surface, "id" refers to identification information, "id1" refers to adding "1" as identification information, and "page 1" indicates page 1.

[0264] Print: front 1 (id1), front 2 (id3), front 3 (id5), back 1 (id2), front 4 (id7), back 2 (id4), front 5 (id9), back 3 (id6), back 4 (id8), back 5 (id10)

[0265] Correction value: Page 1 (id1), Page 2 (id3), ... Page 10 (id10)

[0266] The DFE 2 generates identification information of the page and stores the identification information in association with the correction value of the corresponding page. The DFE 2 sends the raster image data and the correction value to the image processing unit 3 in the order of the pages.

[0267] During inter-page duplex printing, the image processing unit 3 of the liquid discharge device 1 forms an image by sorting the raster image data and the correction value. Furthermore, the image processing unit 3 of the liquid discharge device 1 identifies the front or back of the recording medium based on the identification information. For example, if the number given as the identification information is an odd number, the front surface is determined to face the image processing unit 3, and if the number is an even number, the back surface is determined to face the image processing unit 3.

[0268] With the front surface facing the image processing unit 3, the liquid discharge device 1 receives the correction value obtained from the test print from the DFE 2, and forms an image by performing correction using the received correction value. With the rear surface facing the image processing unit 3, the liquid discharge device 1 forms an image while performing real-time front and rear side positioning by using the correction value based on the deviation amount obtained from the result of previous image formation (i.e., the front surface side of the same page of a given copy).

[0269] <Example of tags added to raster image data>

[0270] Next, refer to Figure 17 The mark added to the raster image data by the second image generating unit 302 is explained. Figure 17 are drawings showing examples of marks added to raster image data.

[0271] Figure 17 An image 92 formed on a sheet 91 is shown. A partially enlarged view 94a shows an end portion 93a on the negative side in the X-axis direction and on the positive side in the Y-axis direction of the image 92. A partially enlarged view 94b shows an end portion 93b on the positive side in the X-axis direction and on the positive side in the Y-axis direction of the image 92.

[0272] As shown in the partially enlarged view 94a, an image of a mark 95a is formed in the end portion 93a. The mark 95a is a figure composed of lines extending in the X-axis direction and the Y-axis direction.

[0273] Furthermore, as shown in a partial enlarged view 94b, an image of a mark 95b is formed in the end portion 93b. Similar to the mark 95a, the mark 95b is a figure composed of lines extending in the X-axis direction and the Y-axis direction.

[0274] The raster image data including the marks 95a and 95b added to the image 92 corresponds to the raster image data of the additional mark. The mark added to the raster image data is not limited to Figure 17 The example shown is a cross-shaped mark, and any mark, such as a cross-shaped mark, can be used as long as the position or deformation, or both, of the image can be detected in the X-axis direction and the Y-axis direction. In addition to adding the mark to the raster image data, characteristic portions of the sheet (such as the edge or corner of the sheet) in the read sheet image data can be identified and used to detect the position and deformation of the image.

[0275] <Example of Correction Value>

[0276] Next, we'll explain correction values. Correction values ​​vary depending on the print job's printing conditions (e.g., duplex printing or single-sided printing). Therefore, whenever the print job's printing conditions change, it's preferable to obtain and store correction values ​​associated with each print job. Below, we'll explain correction values ​​for duplex printing and correction values ​​for single-sided printing. The coordinates explained below correspond to the positions of pixels that make up an image.

[0277] (Double-sided printing)

[0278] In the case of duplex printing, the center coordinates P1 (x1, y1) of the mark position in the raster image data of the additional mark whose image is to be formed on the front surface (i.e., the first surface) match the center coordinates P2 (x2, y2) of the mark position in the raster image data of the additional mark whose image is to be formed on the rear surface (i.e., the second surface). Therefore, a correction value for image formation on the front surface is obtained by geometric calculation. For example, ΔP (x1-x2, y1-y2) (i.e., the difference between (i) the center coordinates P1 (x1, y1) of the mark position in the raster image data of the additional mark whose image is to be formed on the front surface (i.e., the first surface) and (ii) the center coordinates P2 (x2, y2) of the mark position in the raster image data of the additional mark whose image is to be formed on the rear surface (i.e., the second surface)) corresponds to the correction value.

[0279] For example, ΔQ(x1-x2,y1-y2) (e.g., the difference between (i) the center coordinates Q1(x1,y1) of the mark position in the read image data of the rear surface of the sheet whose image will be formed on the front surface (i.e., the first surface) and (ii) the center coordinates Q2(x2,y2) of the mark position in the read image data of the rear surface of the sheet whose image is formed on the rear surface (i.e., the second surface)) corresponds to the correction value.

[0280] (Single-sided printing)

[0281] In the case of single-sided printing, a correction value for image formation on the front surface is obtained by geometric calculation based on the mark position in the raster image data of the additional mark whose image will be formed on the front surface and the center coordinates of the mark position in the read image data of the front surface of the sheet whose image is formed on the front surface.

[0282] (Correct image distortion)

[0283] Next, correction of image deformation is explained. Figure 18A 1 is a diagram showing coordinate points of raster image data to be labeled for explaining an example of a method of correcting image deformation. Figure 18B 1 is a diagram showing coordinate points of read image data for explaining an example of a correction method for image deformation. Figure 18A and 18B In the example of , four coordinate points are arranged in the mark-added raster image data, and four coordinate points are arranged in the read image data.

[0284] exist Figure 18A In the raster image data with additional markings shown in FIG, ideal coordinate points without distortion are obtained. In contrast, in Figure 18B In the read image data shown, due to deformation (expansion and contraction) of the sheet material, the position of point B is shifted by 5 pixels toward the negative side in the X-axis direction and by 5 pixels toward the positive side in the Y-axis direction. Therefore, the deformation of the image can be corrected by performing a geometric transformation operation on the rectangular image composed of coordinate points A, B, C, and D so that the position of point B is shifted by 5 pixels toward the positive side in the X-axis direction and by 5 pixels toward the negative side in the Y-axis direction.

[0285] In this way, multiple coordinate points are arranged in each of the marked raster image data and the read image data, and the deformation of the rectangular image formed by the coordinate points is detected based on the positional shift of the corresponding coordinate points. The rectangular image is then corrected to eliminate the deformation, making it possible to correct the image to be formed on the sheet.

[0286] <Effects of Liquid Discharge Device 1>

[0287] Next, refer to Figures 19 to 21 The effects of the liquid discharge device 1 are explained. First, Figure 19 is a diagram for explaining an example of an image formation result in a case where correction according to the embodiment is not performed. Figure 19 A plurality of pages of a sheet on which an image is formed are shown, wherein page 111 indicates page 1, page 112 indicates page 2, and page 113 indicates page 3.

[0288] Depending on the image to be formed, the amount and distribution of ink that has adhered to the sheet are different, and therefore, the expansion and contraction of the sheet are partially different. Therefore, the positional shift and deformation of the image may differ depending on the printed matter.

[0289] like Figure 19 As shown, on page 111, expansion and contraction increase according to the amount of ink that has adhered to the positive side in the X-axis direction and the positive side in the Y-axis direction. On page 112, expansion and contraction increase according to the amount of ink that has adhered to the negative side in the X-axis direction and the positive side in the Y-axis direction. On page 113, expansion and contraction increase according to the amount of ink that has adhered to the negative side in the X-axis direction and the negative side in the Y-axis direction.

[0290] Next, Figure 20 : is a diagram for explaining an example of raster image data in the case where correction according to the embodiment is performed. Figure 20 shows a sensor 425 (see Figure 2 ) by reading the image formed thereon Figure 19 The image data 121 is the raster image data obtained by (i) obtaining the read image data of pages 111, 112, and 113 and (ii) correcting the raster image data by adding the mark. The raster image data 122 is the raster image data formed on the second page. The raster image data 123 is the raster image data formed on the third page.

[0291] like Figure 20 As shown, in the raster image data 121, the positive side in the X-axis direction and the positive side in the Y-axis direction of the raster image data are expanded so as to correct Figure 19 The expansion and contraction on the positive side in the X-axis direction and the positive side in the Y-axis direction on the page 111 of the image data 122 are corrected. In the raster image data 122, the negative side in the X-axis direction and the positive side in the Y-axis direction of the raster image data are expanded to correct the expansion and contraction on the positive side in the X-axis direction and the Y-axis direction. Figure 19 The expansion and contraction on the negative side in the X-axis direction and the positive side in the Y-axis direction of the page 112. In the raster image data 123, the negative side in the X-axis direction and the negative side in the Y-axis direction of the raster image data are expanded to correct the expansion and contraction. Figure 19Page 113 expands and contracts on the negative side in the X-axis direction and the negative side in the Y-axis direction.

[0292] Next, Figure 21 1 is a diagram for explaining an example of an image formation result in a case where correction according to the embodiment is performed. Figure 21 Shown based on Figure 20 The raster image data 121, 122, and 123 form a plurality of pages of a sheet on which an image is formed. A page 131 indicates a first page, a page 132 indicates a second page, and a page 133 indicates a third page.

[0293] like Figure 21 As shown on page 131, it has been obtained by properly correcting Figure 19 The image is obtained by the expansion and contraction of the page 111 on the positive side in the X-axis direction and the positive side in the Y-axis direction. Similarly, on the page 132, the image has been obtained by appropriately correcting Figure 19 The image is obtained by the expansion and contraction of the page 112 on the negative side in the X-axis direction and the positive side in the Y-axis direction. Similarly, on the page 133, the image has been obtained by appropriately correcting the Figure 19 The image shown is obtained by expanding and contracting the page 113 in the negative side in the X-axis direction and the negative side in the Y-axis direction.

[0294] <Effects of Liquid Discharge Device 1>

[0295] Next, the effects of the liquid discharge device 1 are explained.

[0296] In order to make the ink adhere to the sheet, in the liquid discharge device 1, the deformation amount (expansion and contraction amount) of the sheet varies depending on the amount and distribution of the ink, the amount and distribution of the ink vary depending on the image, and the position shift and deformation of the image may vary depending on the image to be formed on the sheet.

[0297] For example, in a method for forming a representative pattern image on an image support or the like and obtaining a correction amount from an average value of detection results of the pattern images, correction accuracy for correcting positional shifts and image deformation that differ between images may decrease.

[0298] In contrast, in this embodiment, raster image data (i.e., first image data) is obtained, and raster image data (i.e., second image data) of additional marks obtained by adding a predetermined pattern to the raster image data is generated. Then, correction data (i.e., third image data) is generated, the correction data being obtained by correcting each page of the raster image data based on (i) the raster image data of additional marks and (ii) the read image data obtained by reading an image formed on a sheet based on the raster image data of additional marks, and liquid is discharged onto the recording medium based on the correction data.

[0299] Liquid is discharged onto the sheet based on the third image data corrected for each image according to the amount of sheet deformation. This ensures accuracy in correcting the image to be formed on the sheet, even when the amount of sheet deformation varies from image to image. This allows for the formation of a high-quality image on the sheet by correcting for positional shifts and deformation of the image.

[0300] Furthermore, in this embodiment, the correction unit 306 can generate correction data based on the raster image data to which the mark is attached, the read image data, and the print job including the raster image data. The correction value varies depending on the printing conditions of the print job (such as duplex printing or single-sided printing). Therefore, by also generating correction data using information about the print job (including the raster image data), it is possible to more accurately correct the image formed on the sheet.

[0301] <Second embodiment>

[0302] Next, a liquid discharge device 1A according to a second embodiment is explained. In the second embodiment, the same explanations as those of the first embodiment are omitted as appropriate.

[0303] In this embodiment, corrected raster image data is obtained by correcting raster image data or marked raster image data using at least one of (i) a correction value obtained based on the deformation amount of the sheet or (ii) a predefined correction value, so that the number of times the correction value is obtained through calculation is reduced and the calculation load of the image processing unit is reduced.

[0304] <Example of Functional Configuration of Image Processing Unit 3a>

[0305] in this case, Figure 22 1 is a block diagram for explaining the functional configuration of the image processing unit 3a including the liquid discharge device 1a. Figure 22 As shown, the image processing unit 3a includes an adjustment value storage unit 307 and a correction value obtaining unit 305a. The function of the adjustment value storage unit 307 is as follows: Figure 4 Implementation of SSD 34, HDD 35, etc.

[0306] The adjustment value storage unit 307 stores predetermined data (adjustment value) as a correction value for correcting the raster image data of the additional mark. For example, a representative pattern image is formed on a sheet, and the sensor 425 (see Figure 2 ) An average value of results obtained by reading the formed image a plurality of times is stored as a predetermined correction value.

[0307] The correction value obtaining unit 305a can obtain either (i) a correction value calculated based on the deformation amount of the sheet detected by the deformation amount detecting unit 304 or (ii) a predetermined correction value stored in the adjustment value storage unit 307, and output the obtained correction value or the obtained predetermined correction value to the DFE 2. Which of the correction value or the predetermined correction value is obtained by the correction value obtaining unit 305a can be determined by a user of the liquid discharge apparatus 1a using the operation unit 29 of the DFE 2 (see Figure 3 ) or can be determined by the correction value obtaining unit 305a based on the detection result of the deformation amount detection unit 304.

[0308] <Operation and Effect of Liquid Discharge Device 1a>

[0309] As described above, in this embodiment, corrected raster image data is generated by correcting raster image data or marked raster image data using either a correction value obtained based on the amount of sheet deformation or a predetermined correction value. If sheet deformation is substantially the same across all pages, correction is performed using the predetermined correction value. If sheet deformation varies from page to page, correction is performed using a correction value obtained based on the amount of sheet deformation. Consequently, the user's workload for obtaining correction values ​​can be reduced.

[0310] <Third embodiment>

[0311] In this embodiment, the correction according to the embodiment is applied to variable printing. In this case, "variable printing" is a method of forming an image by changing the content of the image to be formed based on data. In variable printing, a single page of a sheet includes: a fixed area in which the content is fixed (i.e., the same) on all pages; and a variable area in which the content varies from page to page. For example, printing the address of a recipient of direct mail is a typical example of variable printing, in which the area of ​​the address corresponds to the variable area, and the area for displaying product information, catalogs, etc. corresponds to the fixed area.

[0312] refer to Figures 23 to 25 The effects of the liquid discharge device according to this embodiment are explained. Figures 23 to 25 The area shaded by diagonal lines in FIG. 8 indicates the above-mentioned variable area, and the area shaded by horizontal lines indicates the above-mentioned fixed area.

[0313] first, Figure 23 is a diagram for explaining an example of an ideal variable printing result. Figure 23 A plurality of pages printed as a variable print sheet are shown. Page 151 indicates the first page of the first copy. Page 152 indicates the second page of the first copy, page 153 indicates the first page of the second copy, page 154 indicates the second page of the second copy, page 155 indicates the first page of the third copy, and page 156 indicates the second page of the third copy.

[0314] Next, Figure 24 is a drawing for explaining an example of variable printing results in a case where correction according to the embodiment is not performed. Figure 24 A plurality of pages printed as a variable print sheet are shown. Page 161 indicates the first page of the first copy, page 162 indicates the second page of the first copy, page 163 indicates the first page of the second copy, page 164 indicates the second page of the second copy, page 165 indicates the first page of the third copy, and page 166 indicates the second page of the third copy.

[0315] In variable printing, a portion of a page serves as a variable area. Therefore, on pages with substantially identical variable areas or pages with variable areas that are substantially symmetrical about the center of the sheet, sheet deformation tends to be the same, and as a result, image position shift and deformation are likely to be the same.

[0316] exist Figure 24 , the variable area on page 163 is substantially the same as the variable area on page 161. On page 164, the variable area is substantially symmetrical with the variable area on page 163 about the center of the sheet. On page 165, the variable area is substantially the same as the variable area on page 161. On page 166, the variable area is substantially the same as the variable area on page 162.

[0317] Therefore, for page 161, page 163, and page 165, the corrected raster image data obtained by correcting the raster image data of the additional mark is generated using the same correction value. For page 162, page 164, and page 166, the corrected raster image data obtained by correcting the raster image data of the additional mark is generated using the same correction value. The correction value acquisition unit 305 can be used to obtain the corrected raster image data based on the deformation amount detection unit 304 (see Figure 5 ) to determine whether to use the same correction value.

[0318] Figure 25 1 is a diagram for explaining an example of variable printing results in a case where correction according to the embodiment is performed. Figure 25A plurality of pages printed as a variable print are shown. Page 171 indicates the first page of the first copy, page 172 indicates the second page of the first copy, page 173 indicates the first page of the second copy, page 174 indicates the second page of the second copy, page 175 indicates the first page of the third copy, and page 176 indicates the second page of the third copy.

[0319] The deformation of the sheet varies from page to page, but the positional shift or deformation, or both, of the image formed on the sheet is alleviated due to the correction.

[0320] In this manner, in the present embodiment, an image to be formed on a sheet can be corrected in variable printing.

[0321] Furthermore, this embodiment obtains page-specific correction values ​​based on a representative pattern formed on a sheet. When forming an image of a recipient's address for a mailed item, this representative pattern can be, for example, a pattern of a postal code, address, and name. In this embodiment, the pattern of the postal code, address, and name are used as calibration markers, and a different correction value is obtained for each of the multiple pages. This ensures accurate correction in variable printing.

[0322] <Fourth embodiment>

[0323] A liquid discharge device 1b according to a fourth embodiment is explained.

[0324] Basic distortion (i.e., distortion that occurs when forming a single image on a single page) can be corrected by applying an affine transformation to a two-dimensional array on the X and Y axes through geometric transformation. In this case, correction values ​​are derived at four points. However, the surface can be corrected using coordinates at three points. Therefore, when arranging and forming two or more images on a single page, correction is performed by printing five or more reference marks in the image formation area.

[0325] Figure 26 are drawings showing examples of marking according to the present embodiment. Figures 27 to 32 1 and 2 are drawings for explaining correction according to the present embodiment. Figure 27 This is the first example. Figure 28 A second example is shown. Figure 29 A third example is shown. Figure 30 A fourth example is shown. Figure 31 A fifth example is shown. Figure 32 A sixth example is shown. Figures 27 to 32In each of the figures, the X-axis and the Y-axis are indicated by arrows. In the X direction along the X axis, the direction indicated by the arrow is represented as the +X direction, and the direction opposite to the +X direction is represented as the -X direction. Similarly, in the Y direction along the Y axis, the direction indicated by the arrow is represented as the +Y direction, and the direction opposite to the +Y direction is represented as the -Y direction.

[0326] like Figure 26 As shown, markers are provided at the four corners of the image (i.e., point A(0,0), point C(200,0), point G(0,200), and point I(200,200)), and also at the center of the image (i.e., point E(100,100)).

[0327] For example, in the case where four images are arranged on a single page, as shown in Figure 27 As shown, marks are formed on the periphery of each image. Alternatively, two or three images may be arranged on a single page, or five or more images may be arranged on a single page. In the case where two images are arranged on a single page, the center point E is not formed (see FIG. Figure 26 ) and forms the marks at the four corners (ie, point A, point B, point C, and point D). When three or more marks are used in each image, 3 points × 2 correction is used. Figure 27 Image "A" in the image and corrected using 3 points × 2 Figure 27 Note that "3 points × 2" means that three markers are corrected twice to correct the quadrilateral.

[0328] like Figure 27 and Figure 28 As shown, when four images are simply arranged on a single page, it is possible to understand how the corresponding images (i.e., images "A" to "D") are deformed. Marks are formed at the four corners of each of the corresponding images (i.e., images "A" to "D"). In this case, at close positions, the images tend to deform in the same direction. For example, in the case where the center of the sheet is displaced in the upper left direction due to expansion and contraction, the lower right of image "A" (on the +X direction side and on the -Y direction side), the lower left of image "B" (on the -X direction side and on the -Y direction side), the upper right of image "C" (on the +X direction side and on the +Y direction side), and the upper left of image "D" (on the -X direction side and on the +Y direction side) are close to each other in position, and therefore, positional shifts with the same tendency may occur at these positions.

[0329] In addition, if Figure 29 and Figure 30 As shown, these nearby marks can be unified if the expansion and contraction at nearby locations have the same trend.

[0330] The position of the mark other than the four corners varies depending on the layout. Figure 31 As shown, in the case of four-image imposition, settings (arrangements) can be made in a region 311 extending in the main scanning direction (ie, X direction) and a region 312 extending in the sub-scanning direction (ie, Y direction).

[0331] like Figure 32 As shown, in the case of six-image imposition, settings can be made in the area 321 extending in the main scanning direction and in the areas 322 and 323 extending in the sub-scanning direction. When the areas are arranged in three columns, settings are made in areas other than two areas. When the areas are arranged in two rows, settings are made in areas other than one area.

[0332] The positions of the setting marks ("T"-shaped mark, "L"-shaped mark and "+"-shaped mark) other than the positions at the four corners are configured to be outside the image 313 (the area surrounded by the dotted line) or the image 324 (the area surrounded by the dotted line) of the trimming mark. These marks are automatically arranged based on the coordinates of the image to be formed on the sheet and the marks at the four corners. Image 313 and image 324 include images to be formed on the sheet in the print job. The image to be formed on the sheet includes trimming marks. The outermost parts of image 313 and image 324 are the boundary lines of the images. In the case of automatic arrangement, the marks are arranged based on the boundary lines of the arranged images. In the case where, for example, the four corners may extend beyond the marks, the mark positions can be specified by the user on the user interface (UI) screen. When the marks are unified, the number of times the user specifies the area to be cut is reduced, which improves usability or reduces processing load.

[0333] <Operation Example of Liquid Discharge Device 1b>

[0334] Figure 33 : is a flowchart showing an example of the correction value calculation operation of the liquid discharge device 1 b .

[0335] First, in step S331 , the liquid discharge apparatus 1 b determines a reference position such as a mark position.

[0336] Next, in step S332 , correction values ​​for the plurality of images are calculated based on the marks formed at the reference positions.

[0337] In this way, the liquid discharge device 1b can obtain a correction value.

[0338] Figure 34 is a flowchart showing an example of detailed operation of correction value calculation of the liquid discharge device 1 b .

[0339] First, in step S341 , the liquid discharge device 1 b sets a flag.

[0340] Next, in step S342 , the liquid discharge apparatus 1 b generates second data by adding data corresponding to the mark to the first image data.

[0341] Next, in step S343 , the printer 4 of the liquid discharge apparatus 1 b forms an image on a sheet based on the second image data.

[0342] Next, in step S344 , the sensor 425 of the liquid discharge device 1 b reads the image formed on the sheet by the printer 4 , and calculates the position of the mark on the sheet based on the read image data.

[0343] Next, in step S345 , the liquid discharge apparatus 1 b calculates a correction value based on the position of the mark.

[0344] Next, in step S346 , the liquid discharge apparatus 1 b stores the calculated correction value in the correction value storage unit 21 .

[0345] In this way, the liquid discharge device 1b can calculate and store the correction value.

[0346] The liquid discharge apparatus 1 b can improve the accuracy of the image forming position by using the correction value stored in the correction value storage unit 21 .

[0347] In this case, the main scanning position correction value is a correction value for correcting the drawing position in a direction perpendicular to the conveying direction of the image (main scanning direction), and the sub-scanning position correction value is a correction value for correcting the drawing position in the conveying direction (sub-scanning direction).

[0348] The main scanning magnification error correction value is a correction value for correcting the image magnification in the main scanning direction, and the sub scanning magnification error correction value is a correction value for correcting the image magnification in the sub scanning direction.

[0349] The main scanning left side deviation correction value, the main scanning right side deviation correction value, the sub scanning top side deviation correction value, and the sub scanning bottom side deviation correction value are correction values ​​used to correct the distortion of the image in the upward (top), downward (bottom), left, and right directions (+X direction side, -X direction side, +Y direction side, -Y direction side), respectively.

[0350] Even in partial registration, test printing, position correction settings, and a method for calculating correction values ​​are used. Even in partial registration, correction value data is stored for each of the multiple images on a corresponding page of a single print job, and correction values ​​can also be stored for each sheet type. The liquid discharge device 1b can apply these stored correction values ​​collectively to all multiple pages in multiple print jobs.

[0351] Although the present invention has been explained above based on the embodiments and examples, the present invention is not limited to the above embodiments and examples. Various additions, changes, modifications, substitutions, etc. can be made to the above embodiments and examples without departing from the gist of the present invention.

[0352] For example, in the above-described embodiments, the imaging device has been explained as a line scan inkjet type image forming device, but the embodiments are not limited thereto. These embodiments can also be applied to a serial scan inkjet type image forming device, and can achieve substantially the same effects as those achieved by the liquid discharge device 1 explained above.

[0353] Furthermore, an embodiment includes a control method for controlling a liquid discharge device. For example, the control method for controlling a liquid discharge device is a control method for controlling a liquid discharge device that forms an image on a recording medium. The control method includes obtaining first image data, generating second image data by adding a predetermined pattern to the first image data, generating third image data by correcting either the first image data or the second image data based on both the second image data and read image data obtained by reading an image formed on the recording medium based on the second image data; and discharging liquid onto the recording medium based on either the second image data or the third image data. Using this control method for controlling a liquid discharge device, it is possible to achieve effects substantially similar to those achieved by the liquid discharge device 1 explained above.

[0354] The embodiment further includes a recording medium. For example, the recording medium stores instructions for causing a liquid discharge device to perform processing including the following steps: obtaining first image data; generating second image data by adding a predetermined pattern to the first image data; generating third image data by correcting either the first image data or the second image data based on the second image data and read image data obtained by reading an image formed on the recording medium based on the second image data; and discharging liquid onto the recording medium based on either the second image data or the third image data. Using this recording medium, it is possible to achieve effects substantially similar to those achieved by the liquid discharge device 1 explained above.

[0355] In addition, the functions of the above-described embodiments may also be implemented by one or more processing circuits. Here, it is assumed that the "processing circuit" includes a processor programmed to perform each function by software, such as a processor implemented in an electronic circuit, a device designed to perform each function as described above, such as an ASIC (Application Specific Integrated Circuit), a DSP (Graphics Signal Processor), an FPGA (Field Programmable Gate Array), and a conventional circuit module.

[0356] This application is based upon and claims the benefit of priority from Japanese Priority Application No. 2020-154275, filed on September 15, 2020, and Japanese Priority Application No. 2021-123609, filed on July 28, 2021, the contents of which are incorporated herein by reference.

[0357] Reference Signs List

[0358] 1 Liquid discharge device

[0359] 2 DFE

[0360] 21 Correction value storage unit

[0361] 3 Image processing unit (example of image processing device)

[0362] 301 First Image Acquisition Unit

[0363] 302 Second image generating unit

[0364] 303 Reading image acquisition unit

[0365] 304 Deformation Detection Unit

[0366] 305 Correction value acquisition unit

[0367] 306 calibration unit

[0368] 307 Adjustment value storage unit

[0369] 4 Printers

[0370] 42 printing units

[0371] 423 ink discharge unit (example of liquid discharge unit)

[0372] 425 Sensor (Example of a reading unit)

[0373] 5 PC

[0374] 6 Printed Materials

[0375] 95a, 95b Markings (Examples of predetermined patterns)

Claims

1. A liquid discharge device for forming an image on a recording medium, comprising: a first image obtaining unit configured to obtain first image data for a test print; a second image generating unit configured to generate second image data for the test printing by adding a predetermined graphic to the first image data; a correction unit configured to generate third image data for production printing by correcting the first image data for each page based on both the second image data and read image data obtained by reading an image formed on the recording medium based on the second image data; as well as A liquid discharge unit is configured to discharge liquid onto the recording medium based on the third image data.

2. The liquid discharge device according to claim 1, further comprising: a reading unit configured to generate read image data by reading an image formed on the recording medium based on the second image data, wherein the correction unit generates the third image data based on both the second image data and the read image data generated by the reading unit.

3. A liquid discharge device according to claim 1 or 2, wherein in a case where an image is formed on two surfaces of the recording medium including a first surface of the recording medium and a second surface on a side opposite to the first surface, the liquid discharge unit discharges the liquid onto the first surface based on the first image data or the second image data, and discharges the liquid onto the second surface on a side opposite to the first surface of the recording medium from which the first surface has been read based on the third image data. 4 . The liquid discharge device according to claim 3 , wherein the second surface is a surface on the opposite side to the first surface of the recording medium from which the first surface has been read.

5. A liquid discharge device according to any one of claims 1 or 2, wherein the correction unit generates the third image data obtained by correcting the first image data using a correction value, and the correction value is calculated by comparing the position of the predetermined graphic in the second image data with the position of the predetermined graphic in the read image data.

6. The liquid discharge device according to claim 1 or 2, further comprising: a correction value obtaining unit configured to obtain a correction value for correcting the first image data or the second image data based on an amount of deformation of the recording medium detected from the second image data and the read image data, The correction unit generates the third image data based on the correction value.

7. The liquid discharge device according to claim 6, further comprising: a correction value storage unit configured to store the correction value, wherein the correction value storage unit generates the third image data based on the correction value obtained by referring to the correction value storage unit. 8 . The liquid discharge apparatus according to claim 6 , wherein in a case where images are formed on a plurality of pages, the correction value obtaining unit obtains correction values ​​that differ between the plurality of pages. 9 . The liquid discharge device according to claim 8 , wherein the correction value obtaining unit obtains correction values ​​that differ between the plurality of pages based on a representative pattern formed on the recording medium. 10 . The liquid discharge device according to claim 6 , wherein the correction value obtaining unit obtains a correction value obtained based on the deformation amount or a predetermined correction value.

11. The liquid discharge device according to any one of claims 1, 2, 4, 7 to 10, wherein: As a test print of a print job, the liquid discharge device generates the second image data based on the first image data, and obtains a correction value for a corresponding page of the print job based on both the second image data and read image data obtained by reading an image formed on the recording medium based on the second image data, and When production printing of the print job is performed, the third image data obtained by correcting the corresponding page using the correction value of the corresponding page is generated, and the liquid is discharged onto the recording medium based on the third image data.

12. The liquid discharge device according to claim 1, wherein in a case where the liquid discharge device performs double-sided printing in production printing of a print job, the liquid discharge device generates, for a first surface of at least one of the pages, the second image data of the first surface based on the first image data, and also generates the third image data of the first surface, the third image data of the first surface being obtained by correcting the second image data of the first surface using a correction value obtained based on data of an image formed on the second surface in a test print, For a second surface of at least one of the pages, the liquid discharge device generates the third image data of the second surface from the first image data of the second surface based on read image data obtained by reading an image formed on the recording medium based on the second image data of the first surface, and The liquid discharge device discharges the liquid onto the recording medium as the production print based on the third image data of the first surface and the third image data of the second surface.

13. The liquid discharge device according to claim 1, wherein in a case where the liquid discharge device performs double-sided printing in production printing of a print job, For a first surface of at least one of the pages, the liquid discharge device generates the third image data of the first surface based on the first image data in the test printing by using a correction value obtained based on data of an image formed on a second surface, the liquid discharge device generates, for a second surface of at least one of the pages, the third image data of the second surface obtained by correcting the first image data of the second surface based on read image data obtained by reading the image formed on the recording medium based on the first image data of the first surface, and The liquid discharge device discharges the liquid onto the recording medium as the production print based on the third image data of the first surface and the third image data of the second surface.

14. A method for controlling a liquid discharge device for forming an image on a recording medium, the method comprising: obtaining first image data for test printing; generating second image data for the test printing by adding a predetermined pattern to the first image data; generating third image data for production printing by correcting the first image data based on both the second image data and read image data obtained by reading an image formed on the recording medium based on the second image data; as well as Liquid is discharged onto the recording medium based on either the second image data or the third image data.

15. A recording medium storing instructions for causing a liquid discharge device to execute a process comprising the following steps: obtaining first image data for test printing; generating second image data for the test printing by adding a predetermined pattern to the first image data; generating third image data for production printing by correcting the first image data based on both the second image data and read image data obtained by reading an image formed on the recording medium based on the second image data; as well as Liquid is discharged onto the recording medium based on the second image data or the third image data.

Images