LIQUID EJECTION DEVICE, CONTROL METHOD FOR LIQUID EJECTION DEVICE, AND STORAGE MEDIUM

Abstract

To secure image correction accuracy of a liquid discharge device.SOLUTION: A liquid discharge device for forming an image on a recording medium includes: a first image acquisition part for acquiring first image data; a second image generation part for generating second image data obtained by adding a predetermined figure to the first image data; a correction part for generating read-out image data of the image formed on the recording medium on the basis of the second image data, and third image data obtained by correcting the first image data for each page on the basis of the second image data; and a liquid discharge part for discharging a liquid onto the recording medium on the basis of the third image data.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection apparatus, a control method for a liquid ejection apparatus, and a storage medium. [Background technology]

[0002] Conventionally, in an image forming apparatus that forms an image on a recording medium, a technique is known that corrects the image formed on the recording medium when the image formation position on the recording medium is shifted or the image is deformed.

[0003] Furthermore, a technique for correcting an image based on the detection result of a figure formed on an image carrier has been disclosed (see, for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a liquid ejection device that forms an image on a recording medium, the expansion / contraction rate of the recording medium varies from page to page depending on image formation conditions such as the image formation speed, or the amount of liquid ejected, and therefore the technology in Patent Document 1 may not be able to correct the image with high precision.

[0005] An object of the present invention is to ensure image correction accuracy in a liquid ejection device. [Means for solving the problem]

[0006] A liquid ejection device according to one aspect of the present invention is a liquid ejection device that forms an image on a recording medium, and includes a first image acquisition unit that acquires first image data, a second image generation unit that generates second image data in which a predetermined figure is added to the first image data, a correction unit that generates third image data by correcting the first image data for each page based on the second image data and read image data of the image formed on the recording medium based on the second image data, and a liquid ejection unit that ejects liquid onto the recording medium based on the third image data. When performing double-sided printing in the actual printing of a print job, the liquid ejection device generates, for the first side of the page, the second image data for the first side from the first image data, and further generates the third image data for the first side corrected from the second image data for the first side using a correction value acquired based on data after image formation of the second side opposite to the first side by test printing; and for the second side, generates the third image data for the second side corrected from the first image data for the second side based on read image data of the image formed on the recording medium based on the second image data for the first side, and ejects liquid onto the recording medium for the actual printing based on the third image data for the first side and the third image data for the second side. do. [Effects of the Invention]

[0007] According to the present invention, it is possible to ensure the accuracy of image correction in the liquid ejection device. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram illustrating an example of the overall configuration of a liquid ejection device according to an embodiment. [Figure 2] FIG. 1 is a diagram illustrating an example of the configuration of a printer according to an embodiment. [Figure 3] FIG. 2 is a block diagram of an example of the hardware configuration of a DFE according to an embodiment. [Figure 4] FIG. 2 is a block diagram illustrating an example of the hardware configuration of an image processing unit according to the embodiment. [Figure 5] FIG. 2 is a block diagram illustrating an example of the functional configuration of an image processing unit according to the first embodiment. [Figure 6] FIG. 4 is a flowchart illustrating an example of the overall operation of the liquid ejection device according to the embodiment. [Figure 7] FIG. 10 is a flowchart illustrating an example of a correction value acquisition operation of the liquid ejection device according to the embodiment. [Figure 8] FIG. 10 is a flowchart illustrating an example of a corrected image forming operation of the liquid ejection device according to the embodiment. [Figure 9] FIG. 10 illustrates an example of a list screen of print jobs. [Figure 10] FIG. 10 is a diagram showing a first example of an image position correction setting screen. [Figure 11] FIG. 10 is a diagram showing a second example of an image position correction setting screen. [Figure 12] FIG. 10 is a diagram showing a third example of an image position correction setting screen. [Figure 13] 10 is a flowchart showing an example of a correction value acquisition operation using a test print by the liquid ejection device according to the embodiment. [Figure 14] FIG. 10 is a diagram showing an example of a list of combinations of correction image forming modes. [Figure 15] FIG. 10 is a flowchart showing an example of a correction operation using a correction value performed by the liquid ejection device according to the embodiment. [Figure 16]10A and 10B are sequence diagrams showing an example of a correction operation using a correction value performed by the liquid ejection device according to the embodiment. [Figure 17] 10A and 10B are diagrams illustrating examples of marks added to drawing data. [Figure 18] 10A and 10B are diagrams showing examples of correction values, in which FIG. 10A shows an example of coordinate points of marked drawing data, and FIG. 10B shows an example of coordinate points of read image data. [Figure 19] 10A and 10B are diagrams illustrating an example of an image formation result without correction according to the embodiment. [Figure 20] 10A and 10B are diagrams illustrating an example of drawing data that has been corrected according to the embodiment. [Figure 21] 10A and 10B are diagrams illustrating an example of an image formation result after correction according to the embodiment. [Figure 22] FIG. 10 is a block diagram illustrating an example of the functional configuration of an image processing unit according to the second embodiment. [Figure 23] FIG. 10 is a diagram illustrating an example of an ideal variable print result. [Figure 24] FIG. 10 is a diagram illustrating an example of a variable print result without correction according to the embodiment. [Figure 25] FIG. 13 is a diagram showing an example of a variable print result after correction according to the third embodiment. [Figure 26] FIG. 10 is a diagram showing an example of a mark according to the fourth embodiment. [Figure 27] FIG. 13 is a diagram illustrating a first example of correction according to the fourth embodiment. [Figure 28] FIG. 13 is a diagram illustrating a second example of correction according to the fourth embodiment. [Figure 29] FIG. 13 is a diagram illustrating a third example of correction according to the fourth embodiment. [Figure 30] FIG. 10 is a diagram illustrating a fourth example of correction according to the fourth embodiment. [Figure 31] FIG. 10 is a diagram illustrating a fifth example of correction according to the fourth embodiment. [Figure 32] FIG. 10 is a diagram illustrating a sixth example of correction according to the fourth embodiment. [Figure 33] FIG. 11 is a flowchart showing an example of a correction value calculation operation of a liquid ejection device according to a fourth embodiment. [Figure 34]FIG. 11 is a flowchart showing a detailed example of the operation of calculating a correction value in the liquid ejection device according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes embodiments of the present invention with reference to the accompanying drawings. In the drawings, the same components are designated by the same reference numerals, and redundant explanations will be omitted where appropriate.

[0010] Furthermore, the embodiments described below are intended to exemplify a liquid ejection device embodying the technical concept of the present invention, and are not intended to limit the present invention to the embodiments described below. Unless otherwise specified, the dimensions, materials, shapes, relative positions, parameter values, etc. of the components described below are intended to be illustrative and not to limit the scope of the present invention. Furthermore, the sizes and positional relationships of components shown in the drawings may be exaggerated for clarity. Note that the terms printing, printing, and image formation in the embodiments are all synonymous.

[0011] In this embodiment, first image data is acquired, and second image data is generated by adding a predetermined figure to the first image data. Then, based on the second image data and scanned image data of an image formed on a recording medium based on the second image data, third image data is generated by correcting the first image data for each page, and liquid is ejected onto the recording medium based on the third image data. By ejecting liquid onto the recording medium based on the third image data corrected for each image according to the amount of deformation of the recording medium, image correction accuracy is ensured even when the amount of deformation of the recording medium differs for each image formed on the recording medium.

[0012] In the following description of the embodiment, ink is an example of a liquid, paper is an example of a recording medium, and a "figure" is referred to as a "mark."

[0013] [First embodiment] <Example of overall configuration of liquid ejection device 1> First, the overall configuration of a liquid ejection device 1 will be described with reference to Fig. 1. Fig. 1 is a block diagram illustrating an example of the overall configuration of the liquid ejection device 1. As shown in Fig. 1, the liquid ejection device 1 has a DFE (Digital Front End) 2, an image processing unit 3, and a printer 4. These are configured to be able to send and receive data or signals to and from each other.

[0014] The liquid ejection device 1 receives a print job from an external device, a PC (Personal Computer) 5, forms an image on paper based on the print job, and outputs a printed matter 6 after the image has been formed. The paper is a sheet material such as plain paper or coated paper. However, the recording medium is not limited to paper, and may be a sheet material such as an overhead projector sheet or film. The sheet material is preferably a cut sheet cut to a predetermined size, but may also be a continuous sheet that has not been cut.

[0015] Based on the print job received from the PC 5, the DFE 2 generates drawing data as an example of first image data using a RIP (Raster Image Processor) engine, and outputs the drawing data to the image processing unit 3.

[0016] The DFE 2 can also receive and store correction values for correcting an image to be formed on paper from the image processing unit 3, and output these correction values to the image processing unit 3 together with the drawing data.

[0017] The image processing unit 3 is an example of an image processing device that executes a process to correct an image to be formed on paper. The image processing unit 3 generates marked drawing data (an example of second image data) in which predetermined marks are added to the drawing data input from the DFE 2. The image processing unit 3 also acquires from the printer 4 the read image data read by a sensor provided in the printer 4.

[0018] The image processing unit 3 calculates and obtains a correction value based on the deformation amount of the paper obtained from the marked drawing data and the read image data. Then, based on this correction value, the image processing unit 3 corrects either the drawing data or the marked drawing data to generate either the corrected drawing data or the marked drawing data (an example of third image data). In the following, for simplicity of explanation, either the corrected drawing data or the marked drawing data will be simply referred to as corrected data. Either the marked drawing data or the corrected data is output to the printer 4.

[0019] The printer 4 ejects ink to form an image on a sheet based on either the mark-added drawing data or the corrected data input from the image processing unit 3.

[0020] Although the example has been shown in which the image processing unit 3 corrects the drawing data generated by the DFE 2, the image processing unit 3 may also correct the image data included in the print job before the DFE 2 generates the drawing data. That is, the image processing unit 3 may correct the RGB image data of R (red), G (green), and B (blue) included in the print job before converting it into CMYK image data 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 first image data.

[0021] <Printer 4 configuration example> Next, the configuration of the printer 4 included in the liquid ejection device 1 will be described with reference to Fig. 2. Fig. 2 is a diagram illustrating an example of the configuration of the printer 4.

[0022] 2, the printer 4 has a paper feed unit 41, a printing unit 42, a drying unit 43, a cooling unit 44, and a conveying unit 45. The arrows displayed between the components, that is, the arrows that start at the paper feed unit 41, pass through the printing unit 42, the drying unit 43, and the cooling unit 44, turn around at the conveying unit 45, pass through the printing unit 42 again, and return to the paper feed unit 41, represent the conveying path P along which paper is conveyed within the printer 4.

[0023] In printer 4, an image is formed on the front surface (first side) of paper fed from paper feed unit 41 in printing unit 42 using ink for image formation. Then, after the ink adhering to the paper is dried in drying unit 43, the paper is discharged using discharge tray 451 of conveyance unit 45. In the case of double-sided printing, in which images are formed on both the front and back sides of the paper, the paper is switched back by reversing unit 452, and an image is again formed on the back surface (second side) of the paper, opposite the front side, in printing unit 42. Thereafter, the paper passes through drying unit 43, cooling unit 44, and conveyance unit 45, and is then discharged using discharge tray 451 or discharge tray 412.

[0024] (Paper feed section 41) The paper feed unit 41 has a paper feed tray 411 on which a plurality of sheets of paper are stacked, and a paper output tray 412 on which sheets of paper with images formed on the back side are stacked and held. The sheets of paper are separated one by one from the paper feed tray 411 and sent out by a feeding device (not shown), and then fed to the printing unit 42. There are no limitations on the configuration of the paper feed unit 41, as long as it can send sheets of paper to the printing unit 42.

[0025] (Printing Department 42) The printing unit 42 has a receiving drum 421 that receives the fed paper, a transport drum 422 that carries and transports the paper on its outer circumferential surface, and an ink ejection unit 423 that ejects ink from nozzles toward the paper carried on the transport drum 422. It also has a transfer drum 424 that delivers the paper transported by the transport drum 422 to the drying unit 43, and a sensor 425 that reads the image formed on the paper.

[0026] The paper transported from the paper supply unit 41 to the printing unit 42 has its leading edge gripped by a paper gripper provided on the surface of the receiving drum 421, and is transported as the surface of the receiving drum 421 moves. The paper transported by the receiving drum 421 is handed over to the transport drum 422 at a position opposite the transport drum 422.

[0027] A paper gripper is also provided on the surface of the transport drum 422, and the leading edge of the paper is gripped by the paper gripper. In addition, multiple suction holes are formed in a distributed manner on the surface of the transport drum 422, and a suction device generates a suction air current in the suction hole, which flows toward the inside of the transport drum 422. The paper transferred from the receiving drum 421 to the transport drum 422 has its leading edge gripped by the paper gripper, and is adsorbed to the surface of the transport drum 422 by the suction air current, and is transported as the surface of the transport drum 422 moves.

[0028] The ink ejection unit 423 is an example of a liquid ejection unit that ejects ink of four colors, K, C, M, and Y, from nozzles onto paper based on either the marked drawing data or the corrected data. An image is formed on paper by the ink ejected by the ink ejection unit 423. The ink ejection unit 423 has an individual ink ejection unit for each ink color. There are no limitations on the configuration of the ink ejection units for each color, and any configuration can be used as long as they eject ink.

[0029] In this embodiment, the ink colors used are four colors: K, C, M, and Y, but are not limited to these. If necessary, an ink ejection unit that ejects ink of a special color such as white, gold, or silver may be provided, or an ink ejection unit that ejects ink that does not form an image, such as a surface coating liquid, may be provided.

[0030] The ink ejection units of the ink ejection section 423 are each controlled in ejection operation by a drive signal corresponding to either the marked drawing data or the corrected data. When the paper carried on the transport drum 422 passes through an area facing the ink ejection section 423, ink of each color is ejected from the nozzles included in the ink ejection units of each color and adheres to the paper, forming an image corresponding to either the marked drawing data or the corrected data. There are no limitations on the configuration of the printing section 42, as long as it forms an image by adhering ink to the paper.

[0031] The sensor 425 is an example of a reading unit that is disposed in the printing unit 42 and reads an image formed on paper. The image read by the sensor 425 is an image formed on paper based on marked drawing data to which predetermined marks have been added. The sensor 425 outputs read image data, which is the result of reading the image, to the image processing unit 3 (see FIG. 1).

[0032] Sensor 425 is a CCD (Charge Coupled Device) line sensor in which pixels are arranged in a one-dimensional array, and each pixel outputs an electrical signal corresponding to the intensity of the received light. The pixel arrangement direction is a direction intersecting the direction in which the paper is transported (the depth direction of the paper surface). Sensor 425 also 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).

[0033] The sensor 425 outputs an electrical signal corresponding to the intensity of light reflected by the image formed on the paper using a pixel array for each color. The image formed on the paper is read using the output of the sensor 425.

[0034] Each sensor 425 may include a light source that irradiates light onto the paper. Irradiating light from the light source onto the paper ensures sufficient brightness for reading by the sensor 425. The sensor 425 may also be configured with a CMOS (Complementary Metal-Oxide-Semiconductor) or a PD (Photo Diode) array instead of a CCD. There are no limitations on the configuration of the sensor 425 as long as it can read an image formed on the paper.

[0035] (Drying section 43) The drying unit 43 dries the ink that has been deposited on the paper in the printing unit 42. The paper transported from the printing unit 42 is dried by heating in the drying unit 43 and then transferred to the cooling unit 44. The ink on the paper is subjected to a drying process, which evaporates the liquid components in the ink, such as water, and fixes the ink on the paper, while also preventing the paper from curling. There are no limitations on the configuration of the drying unit 43, as long as it dries the ink that has been deposited on the paper.

[0036] (Cooling section 44) The cooling unit 44 cools the paper that has been heated in the drying unit 43. Cooling can be achieved by blowing air onto the paper with a fan or by transporting the paper while it is in contact with the surface of a cooling transport drum. There are no limitations on the configuration of the cooling unit 44, as long as it can cool the paper.

[0037] (Transport unit 45) The conveying section 45 has a paper output tray 451 that stacks and holds the paper sheets conveyed from the cooling section 44 in order, and an inversion unit 452 that performs a paper inversion and conveyance process to invert the paper sheets on which an image has been formed in the printing section 42 and send them back to the image forming section 200 for double-sided printing on the paper sheets.

[0038] (Other functional parts) The printer 4 has a paper feed unit 41, a printing unit 42, a drying unit 43, a cooling unit 44, and a conveying unit 45, but other functional units can also be added as appropriate. For example, a pre-processing unit that performs pre-processing for image formation can be added between the paper feed unit 41 and the printing unit 42, or a post-processing unit that performs post-processing for image formation can be added between the cooling unit 44 and the conveying unit 45.

[0039] Examples of pre-treatment sections include a section that applies a treatment liquid to the paper to react with the ink and suppress bleeding, but there are no particular restrictions on the type of pre-treatment. Examples of post-treatment sections include a section that binds multiple sheets of paper on which images have been formed, but there are no particular restrictions on the type of post-treatment.

[0040] In addition, the liquid ejection device 1 has a device in which the ink ejection head and the sheet material move relative to each other, but is not limited thereto. Specific examples include a serial type device that moves the ink ejection head, a line type device that does not move the ink ejection head, and the like.

[0041] Further, the "ink ejection head" is a functional component that ejects and sprays ink from ejection holes (nozzles). As an energy generation source for ejecting ink, a piezoelectric actuator (laminated piezoelectric element and thin film piezoelectric element), a thermal actuator using an electrothermal conversion element such as a heating resistor, a discharge energy generation means such as an electrostatic actuator composed of a diaphragm and a counter electrode, etc. can be used, but the discharge energy generation means used is not limited.

[0042] <Hardware Configuration Example of DFE2> Next, referring to FIG. 3, the hardware configuration of DFE2 will be described. FIG. 3 is a block diagram for explaining an example of the hardware configuration of DFE2.

[0043] As shown in FIG. 3, DFE2 includes a CPU (Central Processing Unit) 21, a ROM (Read Only Memory) 22, a RAM (Random Access Memory) 23, an SSD (Solid State Drive) 24, an HDD (Hard Disk Drive) 25, a GPU (Graphics Processing Unit) 26, an I / F (Interface) 27, an LCD (Liquid Crystal Display) 28, and an operation unit 29. These are connected to each other via a system bus B1 so as to be able to transmit and receive signals or data.

[0044] Among these, the CPU 21 controls the operation of the entire DFE2. The ROM 22 stores programs used for driving the CPU 21 such as an IPL (Initial Program Loader). The RAM 23 is used as a work area for the CPU 21.

[0045] The SSD 24 and the HDD 25 store various data such as programs, etc. The GPU 26 is a processor that performs calculations required for image rendering.

[0046] The I / F 27 is an interface for connecting various external devices, such as the image processing unit 3 and the printer 4. The I / F 27 may also include a network I / F function for data communication over a network.

[0047] The LCD 28 is a display device that displays various types of information such as a cursor, menus, windows, characters, images, etc. The operation unit 29 has input means such as a keyboard with multiple keys for inputting characters, numbers, various instructions, etc., a pointing device for selecting and executing various instructions, selecting a processing target, moving the cursor, etc., and a touch panel display using the LCD 28, and is a component for operating the DFE2.

[0048] <Example of hardware configuration of image processing unit 3> Next, the hardware configuration of the image processing unit 3 will be described with reference to Fig. 4. Fig. 4 is a block diagram illustrating an example of the hardware configuration of the image processing unit 3.

[0049] 4, 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 ASIC (Application Specific Integrated Circuit) 37, an FPGA (Field-Programmable Gate Array) 38, and an I / F 39. These are connected via a system bus B2 so as to be able to transmit and receive signals and data to and from each other.

[0050] Among these, the CPU 31 controls the operation of the entire image processing unit 3. The ROM 32 stores programs used for driving the CPU 31 such as the IPL. The RAM 33 is used as the work 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 necessary for image rendering.

[0051] The ASIC 37 is an integrated circuit that combines the circuits of multiple functions realized by the image processing unit 3. The FPGA 37 is an integrated circuit that combines the circuits of multiple functions realized by the image processing unit 3, and the functions to be realized can be set or changed after the manufacture of the integrated circuit.

[0052] The I / F 39 is an interface for connecting various external devices. The external devices in this case are the DFE 2, the printer 4, etc. Also, the I / F 39 can include the function of a network I / F for data communication using a network.

[0053] <Functional configuration example of the DFE 2 and the image processing unit 3> Next, referring to FIG. 5, the functional configuration of the DFE 2 and the image processing unit 3 will be described. FIG. 5 is a block diagram for explaining an example of the functional configuration of the DFE 2 and the image processing unit 3.

[0054] As shown in FIG. 5, 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 realized by the CPU 31 executing a predetermined program or by the ASIC 37, the FPGA 38, etc.

[0055] The first image acquisition unit 301 inputs and acquires drawing data from the DFE 2. The acquired drawing data is output to the second image generation unit 302.

[0056] The second image generation unit 302 generates marked drawing data by adding a predetermined mark to the drawing data input from the first image acquisition unit 301. The second image generation unit 302 also outputs the generated marked drawing data to the deformation amount detection unit 304 or the printer 4.

[0057] For example, when the image correction according to the embodiment is not performed, the second image generation unit 302 outputs the marked drawing data to the printer 4. When the image correction according to the embodiment is performed, the second image generation unit 302 outputs the marked drawing data to the deformation amount detection unit 304.

[0058] The read image acquisition unit 303 inputs and acquires, from the sensor 425, read image data of an image formed on a sheet based on the marked drawing data.

[0059] The deformation amount detection unit 304 detects the amount of deformation of the paper by calculation based on the marked drawing data and the read image data.

[0060] Here, the amount of ink adhered to the paper varies depending on the area or density of the image formed on the paper. The amount of deformation (expansion / contraction) of the paper due to heating in the drying unit 43 or cooling by the cooling unit 44 may vary depending on the amount of ink adhered to the paper. The deformation amount detection unit 304 calculates the difference in the position, size, etc. of the mark in the marked drawing data and the mark in the scanned image data, and can detect the amount of deformation of the paper from this difference. This mark will be described separately using FIG. 17.

[0061] Although the sensor 425 reads the image as RGB image data, the read image data may be converted to CMYK image data to facilitate comparison with the marked drawing data, which is CMYK image data. This conversion may be performed by the sensor 425 or the read image acquisition unit 303. However, since it is only necessary to calculate differences in the position and size of the marks, the amount of deformation can be detected even if the read image data is RGB image data and the marked drawing data is CMYK image data. Furthermore, if the RGB image data before conversion to CMYK image data by the DFE2 is used as the first image data, the amount of deformation can also be detected by comparing the first image data and the read image data as RGB image data. Furthermore, the sensor 425 may also be monochrome image data. In this case, it is only necessary to calculate differences in the position and size of the marks from the monochrome image data.

[0062] The correction value acquisition unit 305 acquires a correction value by calculation based on the deformation amount of the paper detected by the deformation amount detection unit 304. The correction value is output to the DFE2.

[0063] Here, the DFE 2 has a correction value storage unit 21. The function of the correction value storage unit 21 is realized by the SSD 24 or the HDD 25 in Fig. 3, etc. The correction value storage unit 21 can input and store the correction value acquired by the correction value acquisition unit 305 of the image processing unit 3.

[0064] The correction unit 306 references the correction value storage unit 21 of the DFE2 to acquire the correction value acquired by the correction value acquisition unit 305, and corrects either the drawing data or the marked drawing data based on this correction value to generate corrected data. The DFE2 outputs the corrected data to the printer 4. Note that, although the present embodiment illustrates a configuration in which the DFE2 is provided with the correction value storage unit 21, the present invention is not limited to this. The image processing unit 3 may also be provided with the function of the correction value storage unit 21, or an external device may be provided with the function of the correction value storage unit 21.

[0065] The ink ejection unit 423 (see FIG. 2) in the printer 4 ejects ink onto paper to form an image based on either the marked drawing data input from the second image generation unit 302 or the corrected data input from the correction unit 306. For example, when the correction according to the embodiment is not performed, the ink ejection unit 423 ejects ink based on the marked drawing data. On the other hand, when the image correction according to the embodiment is performed, the ink ejection unit 423 ejects ink based on the corrected data.

[0066] It should be noted that some or all of the functions of the image processing unit 3 described above may be provided in either the DFE 2 or the printer 4. Alternatively, some or all of the functions of the image processing unit 3 may be provided in a distributed manner in the DFE 2 and the printer 4.

[0067] <Example of operation of liquid ejection device 1> Next, the operation of the liquid ejection device 1 will be described with reference to FIGS.

[0068] (Overall operation example) FIG. 6 is a flowchart illustrating an example of the overall operation of the liquid ejection device 1.

[0069] First, in step S61, the liquid ejection device 1 acquires a correction value by calculation and stores it in the DFE2.

[0070] Subsequently, in step S62, the liquid ejection device 1 executes corrected image formation using the acquired correction values.

[0071] In this way, the liquid ejection device 1 can form an image on a sheet that has been corrected using the correction value acquired in advance.

[0072] (Example of correction value acquisition operation) 7 is a flowchart illustrating an example of the correction value acquisition operation of the liquid ejection device 1. The operation in FIG. 7 explains the details of the operation of step S61 in the overall operation in FIG.

[0073] First, in step S71, the first image acquisition unit 301 of the image processing unit 3 inputs and acquires drawing data from the DFE 2. The acquired drawing data is output to the second image generation unit 302.

[0074] Subsequently, in step S72, the second image generation unit 302 generates marked drawing data by adding a predetermined mark to the drawing data input from the first image acquisition unit 301. The second image generation unit 302 outputs the generated marked drawing data to the printer 4.

[0075] Next, in step S73, the ink ejection unit 423 in the printer 4 ejects ink onto the paper based on the mark-added drawing data input from the second image generation unit 302, forming an image on the paper.

[0076] Next, in step S 74 , the sensor 425 in the printer 4 reads the image formed on the paper based on the mark-added drawing data, and outputs it to the read image acquisition unit 303 .

[0077] Subsequently, in step S75, the deformation amount detection unit 304 detects the deformation amount of the paper by calculation based on the marked drawing data and the read image data input via the read image acquisition unit 303.

[0078] Subsequently, in step S76, the correction value acquisition unit 305 acquires a correction value by calculation based on the deformation amount of the paper detected by the deformation amount detection unit 304, and outputs the acquired correction value to the DFE 2.

[0079] Subsequently, in step S77, the correction value storage unit 21 of the DFE 2 stores the correction value input from the correction value acquisition unit 305.

[0080] In this way, the liquid ejection device 1 can obtain and store the correction values.

[0081] (Example of corrected image formation operation) 8 is a flowchart illustrating an example of the corrected image forming operation of the liquid ejection device 1. The operation in FIG. 8 explains the details of the operation of step S62 in the overall operation in FIG.

[0082] Note that the term "page" is used in Figure 8, but in the embodiment, a page refers to one side of a sheet of paper. When single-sided printing, in which an image is formed on one side of a sheet, is performed on multiple sheets of paper, "page 1" refers to the front side (front surface) of the first sheet of paper among the multiple sheets of paper. When double-sided printing, in which an image is formed on both sides of a sheet of paper, is performed on a single sheet of paper, "page 1" refers to the front side of the single sheet of paper, and when double-sided printing is performed on multiple sheets of paper, it refers to the front side of the first sheet of paper among the multiple sheets of paper.

[0083] However, the term "next page" refers to the order in which images are formed. This order of image formation changes depending on the interleaf, so it is not necessarily the next page in the print job. Note that interleaf refers to an image formation method in which image formation on the next sheet begins between the image formation on the front and back of the first sheet.

[0084] In FIG. 8, first, in step S81, the DFE 2 outputs to the image processing unit 3 a correction value corresponding to drawing data for forming an image on the first page of paper, and the drawing data corresponding to this correction value.

[0085] Subsequently, in step S82, the correction unit 306 in the image processing unit 3 receives the correction value and the drawing data from the DFE 2, and corrects the drawing data based on the correction value.

[0086] Next, in step S83, the printer 4 forms an image on paper based on the corrected data.

[0087] Subsequently, in step S84, the DFE 2 determines whether or not to end image formation.

[0088] If it is determined in step S84 that image formation is to be ended (step S84, Yes), the operation ends. On the other hand, if it is determined that image formation is not to be ended (step S84, Yes), in step S85, the DFE 2 outputs the correction value for the "next page" and the drawing data corresponding to the correction value to the image processing unit 3. Thereafter, the process returns to step S82, and the operations from step S82 onwards are repeated.

[0089] In this way, the liquid ejection device 1 can form a corrected image using the correction value acquired in advance.

[0090] The liquid ejection device 1 may execute the correction value acquisition operation of Fig. 7 as a test print before actual printing, and execute the corrected image formation operation of Fig. 8 as actual printing of the print job for which the test print was performed by the operation of Fig. 7. Here, test printing refers to printing in which the recording medium on which an image is formed is not used as the printed matter, and corresponds to trial printing. Actual printing refers to printing in which the recording medium on which an image is formed is used as the printed matter.

[0091] The correction values for each page are acquired and saved using the image formation results of the test print of the print job specified by the user and the scanned image data of the paper, and when the same print job is printed for production, the saved correction values for each page are used to form corrected images. Note that, hereinafter, corrected image formation may be referred to simply as correction.

[0092] For the correction value for each page, in the case of a print job for single-sided printing, the correction value for one side of the image formed is obtained. In the case of a print job for double-sided printing, the correction values for the front and back pages of the image formed are obtained. The correction method settings and test print settings are made on the job setting screen, which is used to make settings for each print job. Here, the front side is an example of the first side, and the back side is an example of the second side.

[0093] <Example of correction value acquisition using test print> (Overall operation) The liquid ejection device 1 can perform test printing for each print job before actual printing and acquire correction values for each page. After acquiring the correction values, the liquid ejection device 1 can select a print job that has been test printed and perform actual printing, thereby forming images in which the image position for each page has been corrected using the correction values acquired from the test printing.

[0094] The liquid ejection device 1 executes test printing of a print job and actual printing of the print job at different times in response to instructions from a user using the operation screen of the DFE 2.

[0095] The liquid ejection device 1 performs test printing in response to an execution instruction using an operation screen for setting image position correction on a job setting screen for each print job selected from a list screen of print jobs input to the DFE 2.

[0096] In the print job settings, it is possible to set the image position correction for the print job, as well as the printing conditions for the print job, such as single-sided or double-sided printing, the print mode (productivity and image quality), the type of recording medium, and the pre-coating conditions (whether or not to apply pre-treatment liquid).

[0097] Image position correction settings for correcting the image position in a print job are performed using a predetermined UI (User Interface). The liquid ejection device 1 displays this UI on the screen of the DFE 2, PC (user terminal), printer 4, or the like.

[0098] In the image position correction setting, it is possible to set correction on, select the type of correction, or turn correction off. When correction is on, it is possible to set image position correction by test printing. The liquid ejection device 1 acquires correction values by performing test printing under the set conditions. The liquid ejection device 1 associates the acquired correction values with the page identification information and stores them in the DFE 2.

[0099] The liquid ejection device 1 performs a test print for each print job. Once the correction values are registered for each print job, the liquid ejection device 1 can perform correction using the correction values associated with the print job even when the print job is executed again, as long as the image position correction settings are not changed. Note that even print jobs for the same file will become different print jobs if they are input to the DFE 2 at different times.

[0100] The DFE2 associates and saves one image position correction setting and correction value for each print job. This is because the expansion / contraction rate of the recording medium during image formation varies depending on the combination of image position correction settings (for example, high image quality with preprocessing and high productivity without preprocessing). When the print job settings change, the DFE2 registers the image position correction settings as a separate print job. Note that the DFE2 can also associate and display multiple combinations of image position correction settings and correction values for a single print job.

[0101] The liquid ejection device 1 performs actual printing using the correction values of the test print saved via a screen for executing a print job in the DFE 2. The data saved by the DFE 2 includes print job identification information, page identification information, and correction identification information (or the correction values themselves), which are associated with each other. The DFE 2 transmits the associated correction values to the image processing unit 3 when forming an image.

[0102] (Example of setting screen) The screen transition from the print job list screen to the print job setting screen in the DFE 2 will be described with reference to Figures 9 to 12. Figure 9 is a diagram showing an example of the print job list screen. Figures 10 to 12 are diagrams showing examples of image position correction setting screens, with Figure 10 showing a first example, Figure 11 showing a second example, and Figure 12 showing a third example.

[0103] When a print job is input to the DFE 2, the liquid ejection device 1 causes the DFE 2 to display a job list screen 501 shown in Fig. 9 on the LCD 28. The user can select multiple print jobs displayed in the list on the operation screen of the DFE 2 and perform print job settings. The print job settings include various settings such as image position correction settings, single-sided or double-sided printing settings, and settings for the color materials to be used.

[0104] The user can instruct the execution of image formation by touching a job execution button 502, and can transition to a print job setting screen by touching a job setting button 503. The user can also delete a print job by touching a job deletion button 504, and can import data for a new print job by touching a job addition button 505.

[0105] When the job setting button 503 is touched, a properties screen 510 is opened, which displays various setting buttons for the print job. The user can display an image position correction setting screen 520 shown in FIGS. 10 to 12 by touching an image position correction setting button 511, among the multiple items displayed on the properties screen 510.

[0106] The image position correction setting screen 520 includes a drop-down image position correction button 521 and a test print selection checkbox 522 for obtaining a correction value for each page. The image position correction button 521 allows the user to select "Off," "Per Page," or "Per Media" for image position correction. "Per Page" refers to control for storing and changing the correction value on a page-by-page basis. "Per Media" refers to control for changing the correction value for each type of paper or recording medium.

[0107] FIG. 10 shows a case where "OFF" is selected by the image position correction button 521, and FIG. 11 shows a case where "per page" is selected by the image position correction button 521.

[0108] When the test print selection checkbox 522 is checked, a test print is performed, and the correction values for each page are associated with this print job and saved in the DFE2. After the test print selection checkbox 522 is checked, only the test print is performed independently before the actual print is performed. The actual print may be performed automatically and consecutively after the test print. Furthermore, after the test print is performed, "per page" may be selectable using the image position correction button 521.

[0109] Examples of situations in which a user may select a correction method include selecting "per media" when the expansion / contraction ratio varies depending on the type of recording medium or paper, or when executing a print job that includes image formation on multiple recording media with different expansion / contraction ratios. In these cases, it is not necessary to perform a test print for each sheet.

[0110] In addition, it is preferable to select "per page" correction when accurate correction is required for each page, or when the print job is expected to have significantly different expansion / contraction rates for each page of the recording medium. Furthermore, when more accurate positional relationship between the front and back sides of a postcard or the like is required, it is preferable to select an appropriate option from among those displayed in the front and back position adjustment box 523. "Front and back position adjustment" refers to real-time front and back position alignment processing (referred to as real-time front and back position alignment) performed in real time while image formation is being performed by the liquid ejection device 1. Front and back position adjustment can only be selected in the case of double-sided printing. If "paper edge" or "detection mark" is selected in the front and back position adjustment box 523, correction is performed to align the back side with the front side. The paper edge corresponds to the edge of the recording medium, and the detection mark corresponds to the mark in the marked drawing data.

[0111] When "detection mark" is selected in the image position correction settings, if margins or no cutting are set in the print job settings, a conflict message may be displayed. The conflict message is a message that notifies you that the settings are conflicting or overlapping.

[0112] When "per page" or "per media" is selected using the image position correction button 521, the number of copies button 524 and each item in the front and back position adjustment box 523 become selectable.

[0113] When the number of copies is changed using the copies button, the DFE2 calculates the average of the four-point detection mark coordinates for each page of each "copy" across multiple recording media. The DFE2 may also store correction values for each page of multiple "copies" and apply them to the correction.

[0114] For a print job for which a test print has been performed once, the DFE2 displays the word "Adjusted" to indicate that the correction values for each page of this print job have been acquired. If the same print job is selected and executed again later, the DFE2 can apply the correction values associated with this print job.

[0115] If "Off" is selected using the image position correction button 521 and either "Paper edge" or "Detection mark" is selected as an item in the front and back position adjustment box 523, the DFE2 determines that there is a conflict in the settings and displays a conflict screen 530 to resolve the conflict, as shown in Figure 12.

[0116] (Details of operation) The following describes the operation of obtaining correction values using test printing by the liquid ejection device 1. In double-sided test printing, the liquid ejection device 1 executes the following operations (1) to (4) in this order.

[0117] (1) An image is formed on the surface of a recording medium. The liquid ejection device 1 forms an image by adding a mark to the surface. At this time, the liquid ejection device 1 does not execute the position correction process for the image. The mark is added at a position 3 mm from the edge of the paper.

[0118] (2) The surface of the recording medium is read and a correction value is obtained. The liquid ejection device 1 reads the surface of the recording medium using the sensor 425, and the DFE2 stores the coordinates (x0y0, x1y1, x2y2, x3y3) of the four marks for each page. When detecting the coordinates of the marks, the DFE2 detects the center of gravity of the corners of each of the four marks. The DFE2 searches for the center of gravity of the edge where the mark changes from black to white. The DFE2 also performs a similar process when acquiring correction values for the back surface of the recording medium. This allows the DFE2 to acquire the amount of misalignment (including image distortion and misalignment) on the front surface without correction. The misalignment is caused by factors such as the expansion and contraction of the recording medium due to a single ink application and drying. The DFE2 applies the amount of misalignment based on the coordinates of the four marks as a correction value to the back surface.

[0119] Here, the drawing data on the front side is not compared with the reading result. Only the position information of the mark on the front side from the reading result is sent to DFE2, which reflects it on the back side and forms an image on the back side. When applied to the back side, the printer 4 changes the correction values and coordinates. Correction values are calculated on the printer 4 side using coordinates that are inverted vertically and horizontally. The printer 4 inverts the coordinates of the mark and retains the inverted coordinates. Coordinates that are not inverted are used for single-sided printing.

[0120] (3) An image is formed on the back side of the recording medium. The liquid ejection device 1 applies a mark to the back surface of the recording medium, and then performs correction (distortion correction and misalignment correction) processing to align the mark with the front surface based on the deviation from the coordinates of the mark on the front surface of the recording medium, before forming an image. This is because if correction is not performed after applying the mark, and the mark is applied after correction, the mark will be applied in the original, undistorted position, and the amount of distortion will not be known.

[0121] (4) The back side of the recording medium is read to obtain the correction value. The liquid ejection device 1 reads the back side of the recording medium using the sensor 425, and compares the back side reading result with the drawing data for the front side of the recording medium using the DFE2 to obtain a correction value for the front side. The liquid ejection device 1 also compares the back side reading result with the front side reading result using the DFE2 to obtain a correction value for the back side. This makes it possible to detect the amount of misalignment on the back side (including image distortion and positional deviation). This misalignment is caused by factors such as expansion and contraction of the recording medium due to the two ink applications and drying.

[0122] When the correction value for the back side is acquired, a correction has already been made to align it with the front side, so the detected misalignment amount is the misalignment amount for the back side, but it also includes the misalignment amount for the front side. The DFE2 acquires the coordinates of four detection marks as correction values for the front side of the same recording medium as the back side that was scanned. The DFE2 acquires the coordinates of four detection marks as the second correction value for the back side. When performing test printing of multiple copies, the DFE2 calculates the average of the four detection mark coordinates for the same page in each copy across all copies. For example, if three copies are to be printed, the DFE2 calculates and stores the average values for the P1 front page of the first copy, the P1 front page of the second copy, and the P1 front page of the third copy at each of the four coordinates.

[0123] Regarding the expansion and contraction of the recording medium (due to ink application or drying), which causes misalignment, the misalignment when reading the front side in operation (2) above is due to the influence of one ink application and one drying. The misalignment when reading the back side in operation (4) is due to the influence of two ink applications and two drying, so the expansion and contraction changes even more. A correction value for the front side is obtained from the results of operation (4), and a correction value for the back side is obtained from the results of operations (2) and (4). The correction values used in the actual printing are the mark position coordinates for the front and back sides obtained in operation (4).

[0124] The DFE 2 stores the position coordinates of the marks, and transmits the position coordinates to the image processing unit 3, which then determines and corrects the correction values. The correction values include the position coordinates of the marks themselves obtained from the scanned image data, the difference values calculated by comparing them with the original data, and the average values of the position coordinates for the same page in multiple copies.

[0125] In the test print for single-sided printing, the liquid ejection device 1 executes the following operations (a) to (b) in this order. (a) An image is formed on the surface of a recording medium. The liquid ejection device 1 forms an image by applying a mark to the surface of the recording medium. At this time, the liquid ejection device 1 does not perform position correction processing of the image. The mark is applied at a position 3 mm from the edge of the paper. (b) The surface of the recording medium is read to obtain a correction value. The liquid ejection device 1 reads the surface of the recording medium using the sensor 425, and the DFE2 stores the coordinates (x0y0, x1y1, x2y2, x3y3) of the four marks for each page. The DFE2 compares the results of the front-side reading with the front-side drawing data to determine the amount of misalignment. This detects the amount of misalignment on the front side without correction (including image distortion and misalignment). This misalignment is caused by factors such as the expansion and contraction of the recording medium due to a single ink application and drying. The DFE2 saves the correction values for the front side only for each page, and the liquid ejection device 1 uses the saved correction values for the actual printing.

[0126] 13 is a flowchart showing an example of the operation of acquiring correction values using test printing by the liquid ejection device 1. The liquid ejection device 1 starts the operation of FIG. 13 in response to an instruction from the user to execute test printing for each print job.

[0127] First, in step S131, the liquid ejection device 1 determines whether the print job for the test print is a single-sided print job using the printer 4.

[0128] In step S131, if it is determined that the printing is one-sided (step S131, Yes), in step S132, the liquid ejection device 1 causes the printer 4 to form an image on the surface of the recording medium to which the mark has been applied.

[0129] Next, in step S133, the liquid ejection device 1 causes the sensor 425 to read the surface of the recording medium on which the mark has been applied.

[0130] Subsequently, in step S134, the liquid ejection device 1 uses the DFE 2 to acquire and store the position coordinates of the marks from the scanned image of each page on the front side.

[0131] Next, in step S135, the liquid ejection device 1 transmits the position information (test print result) stored in the DFE2 to the printer 4 via the DFE2. Then, the liquid ejection device 1 acquires and stores the difference obtained by comparing the position coordinates of the mark in the scanned image of the front side with the position coordinates of the mark to be added to the drawing data before image formation via the printer 4. Note that the difference value between the position coordinates of the mark in the scanned image of the front side and the position coordinates of the mark to be added to the drawing data before image formation may be calculated by the DFE2.

[0132] The operations from step S131 to step S134 are performed by the liquid ejection apparatus 1 based on test printing, and the operation of step S135 is performed by the liquid ejection apparatus 1 based on actual printing.

[0133] On the other hand, if it is determined in step S131 that the printing is not single-sided (step S131, No), in step S136, the liquid ejection device 1 causes the printer 4 to form an image on the surface of the recording medium to which the mark has been applied.

[0134] Subsequently, in step S137, the liquid ejection device 1 causes the sensor 425 to read the surface of the recording medium on which the mark has been applied.

[0135] Subsequently, in step S138, the liquid ejection device 1 uses the DFE 2 to acquire and store the position coordinates of the marks from the scanned image of each page on the front side.

[0136] Subsequently, in step S139, the liquid ejection device 1 obtains and stores the difference between the position coordinates of the mark in the scanned image of the front surface and the position coordinates of the mark to be added to the drawing data before image formation, using the DFE 2.

[0137] Next, in step S140, the liquid ejection device 1 causes the printer 4 to apply a mark, and then corrects the mark using the acquired difference to form an image on the back side of the recording medium.

[0138] Next, in step S141, the liquid ejection device 1 causes the sensor 425 to read the rear surface of the recording medium to which the mark has been applied.

[0139] Next, in step S142, the liquid ejection device 1 acquires and stores the position coordinates of the marks from the scanned image of each page on the back side.

[0140] Next, in step S143, the liquid ejection device 1 transmits the position information (test print result) of the mark on the back surface stored in the DFE2 to the printer 4. Then, the liquid ejection device 1 acquires and stores the difference obtained by comparing the position coordinates of the mark in the read image of the back surface with the position coordinates of the mark to be added to the drawing data before image formation using the printer 4. Note that the difference value between the position coordinates of the mark in the read image of the back surface and the position coordinates of the mark to be added to the drawing data before image formation may be calculated by the DFE2.

[0141] The operations from step S136 to step S142 are performed by the liquid ejection apparatus 1 based on the test print, and the operation of step S143 is performed by the liquid ejection apparatus 1 based on the actual print.

[0142] In this way, the liquid ejection device 1 can obtain correction values using the test print.

[0143] Fig. 14 is a diagram showing an example of a list of combinations of correction image formation modes. (b) shown in Fig. 14 corresponds to the correction in operation (2) and operation (4) described above as the operation of the liquid ejection device 1 in test printing in double-sided printing. (c) shown in Fig. 14 corresponds to a real-time front / back registration mode in which the front side uses the correction value of the test print and the back side is corrected based on the reading result of the front side (corrected) of the actual print.

[0144] In the real-time front / back alignment (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 adds the mark and controls image formation. The liquid ejection device 1 calculates a correction value using the image processing unit 3 based on the reading result of the front side, and corrects the back side.

[0145] In the real-time front-back alignment of (c), if correction using the edge of the recording medium is selected, the image processing unit 3 reads the edge of the recording medium and corrects the back side without adding a mark. Correction using the edge of the recording medium calculates the difference between the length and width of the recording medium used for image formation and the recording medium size of the read data after printing on the front side.

[0146] Backside correction (matching the front and back) includes the following two methods. (A) The front side of the actual print (a mark is printed on the front side or the edge of the recording medium) is read, and the back side is corrected to match the front side (real-time front-back registration). (B) Perform the above (A) on a test print in advance, save the correction amount at that time, and then perform correction using the saved correction amount. When printing the actual print, there is no need to print marks.

[0147] It should be noted that a method other than the method shown in FIG. 14 can also be selected as the method for correcting the back surface.

[0148] (Regarding correction values) A specific example of the correction values (coordinates) obtained by test printing will be described below. In other words, the correction values obtained by test printing are difference values calculated by comparing the marks formed on the recording medium with the marks in the original drawing data for each page of each print job.

[0149] 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 side misalignment correction value, a main scanning right side misalignment correction value, a sub-scanning upper side misalignment correction value, and a sub-scanning lower side misalignment correction value.

[0150] The main scanning position is the position of the image in the direction perpendicular to the transport direction. The sub-scanning position is the position of the image in the 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 misalignment correction value, main scanning right misalignment correction value, sub-scanning upper misalignment correction value, and sub-scanning lower misalignment correction value are correction values that correct distortions in the top, bottom, left, and right of the image.

[0151] (Regarding front and back alignment) Front and back registration is performed during actual printing for a double-sided print job for which test printing has already been completed and when the real-time front and back registration setting is on.

[0152] The liquid ejection device 1 forms an image on the front side of the recording medium while making corrections using the correction values acquired in operation (4) of acquiring correction values using the test print. Then, the sensor 425 reads the front side of the recording medium. The liquid ejection device 1 then forms an image on the back side while making corrections to match the read results of the image formed on the front side in the actual printing. In this case, as in operation (3) of acquiring correction values using the test print, marks are added to detect distortion before correction. Then, the liquid ejection device 1 reads the back side of the recording medium with the sensor 425. However, in this embodiment, although read data for the back side is acquired, it is not used for position correction.

[0153] (Example of correction operation during production printing) 15 is a flowchart showing an example of the operation of performing correction using the correction value in actual printing by the liquid ejection device 1. The liquid ejection device 1 starts the operation of FIG. 15 after completing execution of test printing for each print job.

[0154] First, in step S151, the liquid ejection apparatus 1 stores the correction values acquired by the DFE 2 through test printing.

[0155] Subsequently, in step S152, the liquid ejection device 1 starts executing the actual printing of the print job.

[0156] Next, in step S153, the liquid ejection device 1 determines whether or not the correction setting is on.

[0157] If it is determined in step S153 that it is on (Yes in step S153), in step S154 the liquid ejection device 1 either does not perform correction on either the front or back side, or applies a predetermined correction value to all pages for correction. Then, the liquid ejection device 1 ends its operation after the correction is completed.

[0158] On the other hand, if it is determined in step S153 that the correction setting is not on (step S153, No), then in step S155 the liquid ejection device 1 determines whether the correction setting is image position correction for each page.

[0159] In step S155, if it is determined that image position correction is to be performed for each page (step S155, Yes), in step S156, the liquid ejection device 1 determines whether or not real-time front-to-back position adjustment setting is selected.

[0160] If it is determined in step S156 that the real-time front-to-back alignment setting has been selected (Yes in step S156), then in step S157 the liquid ejection device 1 corrects each page using the correction value for each page previously obtained by test printing. The liquid ejection device 1 forms an image while correcting each page using the previously obtained correction value on one side in the case of single-sided printing, or on both sides in the case of double-sided printing. After image formation is complete, the liquid ejection device 1 ends its operation.

[0161] On the other hand, if it is determined in step S156 that the mark has not been selected, the liquid ejection device 1 determines in step S158 whether or not to perform real-time front-to-back alignment using the mark.

[0162] If it is determined in step S158 that real-time front-to-back alignment should be performed using marks (Yes in step S158), then in step S159, the liquid ejection device 1 performs correction using the correction values for each page previously obtained by test printing, then performs image processing to add marks, and then forms an image on the front side of the recording medium. Thereafter, the liquid ejection device 1 performs correction in accordance with the mark position detection results for the front side in actual printing, and forms an image on the back side of the recording medium (real-time front-to-back alignment).

[0163] On the other hand, if it is determined in step S158 that real-time front-to-back alignment will not be performed using the marks (step S158, No), in step S160, the liquid ejection device 1 forms an image on the front side while making corrections using the correction values for each page obtained in advance by test printing. Thereafter, the liquid ejection device 1 forms an image on the back side while making corrections in accordance with the detection results of the recording medium edge on the front side in actual printing (real-time front-to-back alignment).

[0164] Furthermore, if it is determined in step S155 that image position correction is not required for each page (step S155, No), in step S161, the liquid ejection device 1 performs correction using a correction value that is preset according to the type of recording medium for all pages of the print job. In this case, it is also possible to select real-time front-to-back alignment. If real-time front-to-back alignment is selected, image formation on the back side is corrected to match image formation on the front side. In this case, it is possible to select whether to use a mark or a recording medium edge.

[0165] In this way, the liquid ejection device 1 can execute the correction process using the correction value in the actual printing.

[0166] FIG. 16 is a sequence chart showing an example of a correction operation using the correction value by the liquid ejection device 1.

[0167] In FIG. 16, first, in response to an input instruction from a user, the PC 5 transmits a print job to the liquid ejection apparatus 1, and then, in step S171, the liquid ejection apparatus 1 generates job identification information using the DFE 2.

[0168] The operations up to step S171 correspond to the test print execution operation and the correction value acquisition operation for each page.

[0169] Next, the user inputs print job settings and correction value settings, and then issues an instruction to execute a test print. In response to this instruction, in step S172, the liquid ejection device 1 generates page identification information for the print job using the DFE 2, and then starts executing the test print for the print job. The DFE 2 transmits the drawing data and page identification information for the print job to the image processing unit 3.

[0170] Next, in step S173, the liquid ejection device 1 causes the image processing unit 3 to perform image formation control using the drawing data.

[0171] Next, in step S174, the liquid ejection device 1 causes the printer 4 to form an image based on the drawing data, and also causes the sensor 425 to read the image formed on the recording medium and send the read data to the image processing unit 3.

[0172] Next, in step S175, the liquid ejection device 1 uses the mark for each page or the recording medium edge to obtain a correction value by the image processing unit 3, and transmits the correction value associated with the page identification information to the DFE 2.

[0173] Subsequently, in step S176, the liquid ejection device 1 stores the correction value for each piece of page identification information by using the DFE 2 in association with the job identification information.

[0174] The operations from step S172 to step S176 correspond to the test print execution operation and the correction value acquisition operation for each page.

[0175] Thereafter, in response to a user's instruction to execute actual printing, the DFE 2 transmits the drawing 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 actual printing for a print job for which test printing has already been executed and correction values have been obtained. The actual printing may be executed automatically after the test printing. The user can also select a past print job and issue an instruction to execute actual printing.

[0176] Next, in step S177, the liquid ejection device 1 causes the image processing unit 3 to perform correction for each page based on the drawing data received from the DFE 2, the page identification information, and the correction value associated with the page identification information.

[0177] Subsequently, in step S178, the liquid ejection device 1 causes the image processing unit 3 to perform image formation control using the corrected data.

[0178] Next, in step S179, the liquid ejection device 1 causes the printer 4 to form an image based on the corrected data, and also causes the sensor 425 to read the image formed on the recording medium and send the read data to the image processing unit 3.

[0179] Next, if the real-time front / back alignment setting is on in the correction settings, in step S180, the liquid ejection device 1 corrects the drawing data for the back side of double-sided printing using the image processing unit 3 to match the reading results for the front side of the same page.

[0180] Next, in step S181, the liquid ejection device 1 causes the image processing unit 3 to control image formation on the back side using the corrected data.

[0181] Next, in step S182, the liquid ejection device 1 causes the printer 4 to form an image based on the corrected data, and also causes the sensor 425 to read the image formed on the recording medium and transmit the read data to the image processing unit 3. Note that the read data of the back side is not used in the correction process in this embodiment, but is used for other processes such as defect detection.

[0182] The operations from step S177 to step S182 correspond to the operation of executing actual printing using the correction values for each page.

[0183] In this way, the liquid ejection device 1 can perform correction using the correction value. By performing correction for each page through test printing and actual printing, it is possible to obtain an appropriate image even if the amount of paper deformation differs from page to page.

[0184] (Regarding application of correction values during interleafing) A method for determining whether an image is to be formed on the front side or the back side during interleaf and applying the stored correction value will be described.

[0185] During interleaf printing, the liquid ejection device 1 alternately forms images on the front and back sides in the order shown below, and assigns identification information to each printed page. The liquid ejection device 1 rearranges the correction values in the order of image formation and saves them using the DFE 2. Note that in the following, for example, "Front 1" means the first page on the front side, "id" means identification information, "id1" means that "1" has been assigned as identification information, and "Page 1" means that it is the first page. 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) Correction value: Page 1 (id1), Page 2 (id3), ... Page 10 (id10)

[0186] The DFE 2 generates page identification information and stores the information in association with the correction value for each page. The DFE 2 transmits the drawing data and the correction values to the image processing unit 3 in page order.

[0187] During interleaf printing, the liquid ejection device 1 rearranges the drawing data and correction values using the image processing unit 3 to form an image. The liquid ejection device 1 also recognizes the front or back of the recording medium based on the identification information using the image processing unit 3. For example, if the number assigned as the identification information is an odd number, it is determined to be the front side, and if it is an even number, it is determined to be the back side.

[0188] In the case of the front side, the liquid ejection device 1 receives the correction value acquired from the transmitted test print from the DFE 2 and performs image formation while making corrections using the correction value.In the case of the back side, the liquid ejection device 1 performs image formation while performing real-time front-to-back alignment using a correction value based on the amount of misalignment acquired from the image formation result of the previous number (the front side of the same page in the set).

[0189] <Example of marks added to drawing data> Next, a mark that the second image generating unit 302 adds to the drawing data will be described with reference to Fig. 17. Fig. 17 is a diagram illustrating an example of a mark that is added to the drawing data.

[0190] 17 shows an image 92 formed on a sheet of paper 91. A partially enlarged view 94a shows an end 93a of the image 92 on the negative side in the X-axis direction and the positive side in the Y-axis direction, and a partially enlarged view 94b shows an end 93b of the image 92 on the positive side in the X-axis direction and the positive side in the Y-axis direction.

[0191] As shown in the partially enlarged view 94a, an image of a mark 95a is formed on the end portion 93a. The mark 95a is a figure made up of lines extending in the X-axis direction and the Y-axis direction.

[0192] As shown in a partially enlarged view 94b, an image of a mark 95b is formed on the end portion 93b. Like the mark 95a, the mark 95b is also a figure made up of lines extending in the X-axis direction and the Y-axis direction.

[0193] The drawing data of an image in which marks 95a and 95b are added to image 92 corresponds to the marked drawing data. Note that the marks added to the drawing data are not limited to those exemplified in Fig. 17, and any mark, such as a cross mark, can be used as long as it can detect the position and / or deformation of the image in the X-axis and Y-axis directions. Note that in addition to adding marks to the drawing data, characteristic parts of the paper itself, such as the edges and corners of the paper, may be recognized in the scanned image data of the paper and used to detect the position and deformation of the image.

[0194] <Example of correction value> Next, correction values will be explained. Because correction values differ depending on the printing conditions of a print job, such as double-sided printing or single-sided printing, it is preferable that the correction values be acquired each time the printing conditions of the print job are changed and stored in association with each individual print job. Below, correction values for double-sided printing and single-sided printing will be explained. Note that the coordinates shown below correspond to the positions of the pixels that make up the image.

[0195] (For double-sided printing) In the case of double-sided printing, the center coordinate P1 (x1, y1) of the mark position in the mark-added drawing data for forming an image on the front side (first side) coincides with the center coordinate P2 (x2, y2) of the mark position in the mark-added drawing data for forming an image on the back side (second side). Therefore, a correction value for forming an image on the front side is obtained by geometric calculation. For example, the correction value may be ΔP(x1-x2, y1-y2), which is the difference between the center coordinate P1 (x1, y1) of the mark position in the mark-added drawing data for forming an image on the front side (first side) and the center coordinate P2 (x2, y2) of the mark position in the scanned image data for the back side of the paper on which an image is formed on the back side (second side).

[0196] For example, the correction value is ΔQ(x1-x2, y1-y2), which is the difference between the center coordinate Q1(x1, y1) of the mark position in the read image data of the back side of a sheet of paper on which an image is formed on the front side (first side) and the center coordinate Q2(x2, y2) of the mark position in the read image data of the back side of a sheet of paper on which an image is formed on the back side (second side).

[0197] (For single-sided printing) In the case of single-sided printing, the correction value for forming an image on the front side is obtained by geometric calculation based on the center coordinates of the mark position in the marked drawing data for forming an image on the front side and the mark position in the read image data of the front side of the paper on which the image is formed on the front side.

[0198] (When correcting image distortion) Next, correction of image deformation will be described. Figure 18 is a diagram showing an example of a method for correcting image deformation, where (a) is a diagram showing an example of coordinate points of marked drawing data, and (b) is a diagram showing an example of coordinate points of read image data. In the example of Figure 18, four coordinate points are arranged in the marked drawing data, and four coordinate points are arranged in the read image data.

[0199] The marked drawing data shown in Figure 18(a) provides ideal coordinate points without any deformation. In contrast, in the scanned image data shown in Figure 18(b), the coordinate position of point B is shifted by 5 pixels in the negative X-axis direction and 5 pixels in the positive Y-axis direction due to deformation (expansion) of the paper. Therefore, the deformation of the image can be corrected by performing a geometric transformation operation on the rectangular image formed by coordinate points A, B, C, and D so that the coordinate position of point B is shifted by 5 pixels in the positive X-axis direction and 5 pixels in the negative Y-axis direction.

[0200] In this way, multiple coordinate points are placed within each of the marked drawing data and the scanned image data, and deformation of the rectangular image formed by the coordinate points is detected from the positional deviation of each coordinate point.The rectangular image is then corrected to eliminate the deformation, thereby correcting the image formed on the paper.

[0201] <Action of Liquid Discharge Device 1> Next, the operation of the liquid ejection device 1 will be described with reference to FIGS. First, Fig. 19 is a diagram illustrating an example of an image formation result when correction according to the embodiment is not performed. Fig. 19 shows multiple pages of paper on which images have been formed, with page 111 representing the first page, page 112 representing the second page, and page 113 representing the third page.

[0202] The amount and distribution of ink applied to the paper varies depending on the image being formed, which causes the paper to expand and contract in different parts, which can result in different image misalignment and deformation for each printed item.

[0203] As shown in Figure 19, on page 111, shrinkage increases depending on the amount of ink applied on the positive X-axis direction and the positive Y-axis direction. On page 112, shrinkage increases depending on the amount of ink applied on the negative X-axis direction and the positive Y-axis direction. On page 113, shrinkage increases depending on the amount of ink applied on the negative X-axis direction and the negative Y-axis direction.

[0204] Next, Fig. 20 is a diagram illustrating an example of drawing data when correction according to the embodiment is performed. Fig. 20 shows drawing data corrected based on the read image data obtained by sensor 425 (see Fig. 2) reading each of pages 111, 112, and 113 of Fig. 19 formed on paper, and the marked drawing data. Drawing data 121 represents the drawing data to be formed on the first page, drawing data 122 represents the drawing data to be formed on the second page, and drawing data 123 represents the drawing data to be formed on the third page.

[0205] 20, in drawing data 121, the drawing data is expanded on the positive X-axis direction and the positive Y-axis direction to correct for shrinkage on the positive X-axis direction and the positive Y-axis direction of page 111 in Fig. 19. In drawing data 122, the drawing data is expanded on the negative X-axis direction and the positive Y-axis direction to correct for shrinkage on the negative X-axis direction and the positive Y-axis direction of page 112 in Fig. 19. In drawing data 123, the drawing data is expanded on the negative X-axis direction and the negative Y-axis direction to correct for shrinkage on the negative X-axis direction and the negative Y-axis direction of page 113 in Fig. 19.

[0206] Next, Fig. 21 is a diagram illustrating an example of an image formation result when correction according to the embodiment is performed. Fig. 21 shows multiple pages of paper on which images are formed based on the drawing data 121, 122, and 123 of Fig. 20, with page 131 representing the first page, page 132 representing the second page, and page 133 representing the third page.

[0207] As shown in Fig. 21, for page 131, an appropriate image is obtained in which the shrinkage in the positive X-axis direction and the positive Y-axis direction of page 111 in Fig. 19 has been corrected. Similarly, for page 132, an appropriate image is obtained in which the shrinkage in the negative X-axis direction and the positive Y-axis direction of page 112 in Fig. 19 has been corrected, and for page 133, an appropriate image is obtained in which the shrinkage in the negative X-axis direction and the negative Y-axis direction of page 113 in Fig. 19 has been corrected.

[0208] <Effects of the liquid ejection device 1> Next, the effects of the liquid ejection device 1 will be described.

[0209] Because liquid ejection devices deposit ink onto paper, the amount of deformation (expansion / contraction) of the paper varies depending on the amount and distribution of ink deposited, which differs for each image, and the positional deviation and deformation of the image may differ for each image formed on the paper.

[0210] In a method in which a representative pattern image is formed on an image carrier or the like and the correction amount is obtained from the average value of the detection results of the pattern image, the accuracy of correcting image misalignment and deformation, which differ from image to image, may decrease.

[0211] In this embodiment, drawing data (first image data) is acquired, and marked drawing data (second image data) is generated by adding a predetermined figure to the drawing data. Then, based on the marked drawing data and read image data of an image formed on paper based on the marked drawing data, corrected data (third image data) is generated by correcting the drawing data for each page, and liquid is ejected onto a recording medium based on the corrected data.

[0212] By ejecting liquid onto the paper based on the third image data corrected for each image according to the amount of deformation of the paper, it is possible to ensure the accuracy of correction of the image formed on the paper even when the amount of deformation of the paper differs for each image, and it is possible to form a high-quality image on the paper with the image misalignment and deformation corrected.

[0213] In this embodiment, the correction unit 306 can also generate corrected data based on the marked drawing data, the scanned image data, and a print job that includes the drawing data. The correction value varies depending on the printing conditions of the print job, such as double-sided printing or single-sided printing. Therefore, by generating the corrected data using information about the print job that includes the drawing data, the image formed on the paper can be corrected more accurately.

[0214] [Second embodiment] Next, a liquid ejection device 1a according to a second embodiment will be described, with the explanation of portions that overlap with the first embodiment being omitted where appropriate.

[0215] In this embodiment, the number of times correction values are obtained by calculation is reduced, and the computational load on the image processing unit is reduced, by generating corrected drawing data by correcting either the drawing data or the marked drawing data using either a correction value obtained based on the deformation amount of the paper or a predetermined correction value.

[0216] <Example of functional configuration of image processing unit 3a> 22 is a block diagram illustrating an example of the functional configuration of the image processing unit 3a included in the liquid ejection device 1a. As shown in FIG. 22, the image processing unit 3a has an adjustment value storage unit 307 and a correction value acquisition unit 305a. The function of the adjustment value storage unit 307 is realized by the SSD 34 or HDD 35 in FIG. 4, etc.

[0217] The adjustment value storage unit 307 stores predetermined adjustment values for correcting the marked drawing data. For example, a representative pattern image is formed on a sheet of paper, and the formed image is read multiple times by the sensor 425 (see FIG. 2 ). The average value of the results is stored as the predetermined adjustment value.

[0218] The correction value acquisition unit 305a can acquire either a correction value calculated based on the deformation amount of the paper detected by the deformation amount detection unit 304 or a predetermined correction value stored in the adjustment value storage unit 307, and output it to the DFE 2. Which correction value the correction value acquisition unit 305a acquires may be set by the user of the liquid ejection device 1a using the operation unit 29 (see FIG. 3) of the DFE 2, or the correction value acquisition unit 305a may determine based on the detection result of the deformation amount detection unit 304.

[0219] <Functions and Effects of Liquid Discharger 1a> As described above, in this embodiment, the drawing data or the marked drawing data is corrected using either a correction value acquired based on the amount of deformation of the paper or a predetermined correction value to generate corrected drawing data. If the deformation of the paper is approximately the same for each page, the correction is performed using a predetermined correction value. If the deformation of the paper is different for each page, the correction is performed using a correction value acquired based on the amount of deformation of the paper. This reduces the workload for the user to acquire the correction value.

[0220] [Third embodiment] In this embodiment, the correction according to the embodiment is applied to variable printing. Here, variable printing refers to a method of forming an image by changing the content of the image based on data. In variable printing, a single page of paper contains fixed areas where the content is fixed (common) for each page, and variable areas where the content is variable for each page. For example, printing addresses on direct mail is a typical example of variable printing, with the address area being a variable area and the area displaying product information or a catalog being a fixed area.

[0221] The operation of the liquid ejection device according to this embodiment will be described with reference to Figures 23 to 25. Note that the areas indicated by diagonal hatching in Figures 23 to 25 indicate the variable areas, and the areas indicated by horizontal hatching indicate the fixed areas.

[0222] First, Fig. 23 is a diagram illustrating an example of an ideal variable printing result. Fig. 23 shows multiple pages of variable-printed paper, with page 151 being the first page of the first copy, page 152 being the second page of the first copy, page 153 being the first page of the second copy, page 154 being the second page of the second copy, page 155 being the first page of the third copy, and page 156 being the second page of the third copy.

[0223] Next, Fig. 24 is a diagram illustrating an example of a variable printing result when correction according to the embodiment is not performed. Fig. 24 shows multiple pages of variable-printed paper, with page 161 being the first page of the first copy, page 162 being the second page of the first copy, page 163 being the first page of the second copy, page 164 being the second page of the second copy, page 165 being the first page of the third copy, and page 166 being the second page of the third copy.

[0224] In variable printing, part of the page becomes a variable area, so on pages where the variable areas are approximately equal, or where the variable areas are approximately symmetrical across the center of the paper, the tendency for the paper to deform will be equal, which may result in equal image misalignment and deformation.

[0225] 24, page 163 has a variable area that is approximately equal to that of page 161. Page 164 has a variable area that is approximately symmetrical to that of page 163 across the center of the paper. Page 165 has a variable area that is approximately equal to that of page 161, and page 166 has a variable area that is approximately equal to that of page 162.

[0226] Therefore, the common correction value is used to correct the marked drawing data to generate corrected drawing data for pages 161, 163, and 165. The common correction value is also used to correct the marked drawing data to generate corrected drawing data for pages 162, 164, and 166. Whether or not to use the common correction value can be determined by the correction value acquisition unit 305 based on the detection result of the deformation amount detection unit 304 (see FIG. 5).

[0227] Fig. 25 is a diagram illustrating an example of a variable printing result after correction according to the embodiment. Fig. 25 shows multiple pages that have been variably printed, with page 171 being the first page of the first copy, page 172 being the second page of the first copy, page 173 being the first page of the second copy, page 174 being the second page of the second copy, page 175 being the first page of the third copy, and page 176 being the second page of the third copy.

[0228] Although the deformation of the paper differs for each page, the image formed on the paper has reduced misalignment and / or deformation due to the correction.

[0229] In this way, in this embodiment, it is possible to correct the image formed on the paper in variable printing.

[0230] In this embodiment, different correction values are obtained for each of multiple pages based on a representative pattern formed on the paper. This representative pattern is, for example, a pattern of postal code, address, and name when forming an image of a mail address. In this embodiment, the postal code, address, and name pattern is used as a correction mark, and different correction values are obtained for each of multiple pages. This ensures correction accuracy in variable data printing.

[0231] [Fourth embodiment] A liquid ejection device 1b according to a fourth embodiment will be described.

[0232] Basic deformation, that is, deformation that occurs when forming one image per page, can be corrected by performing an affine transformation on the two-dimensional array of the X and Y axes using geometric transformation. In this case, the correction value is found using four points. However, since surface correction is possible using the coordinates of three points, when forming two or more images on one page, correction is performed by printing five or more reference marks in the image formation area.

[0233] Fig. 26 is a diagram showing an example of a mark according to this embodiment. Figs. 27 to 32 are diagrams explaining correction according to this embodiment, with Fig. 27 being a first example, Fig. 28 being a second example, Fig. 29 being a third example, Fig. 30 being a fourth example, Fig. 31 being a fifth example, and Fig. 32 being a sixth example. In each diagram, the X-axis and Y-axis are indicated by arrows, and in the X direction along the X-axis, the direction in which the arrow points is defined as the +X direction, and the direction opposite to the +X direction is defined as the -X direction. Similarly, in the Y direction along the Y-axis, the direction in which the arrow points is defined as the +Y direction, and the direction opposite to the +Y direction is defined as the -Y direction.

[0234] As shown in FIG. 26, the marks are placed at points A (0,0), C (200,0), G (0,200), and I (200,200) at the four corners of the image, and at point E (100,100) in the center of the image.

[0235] For example, if there are four images to be placed on one page, marks are formed around each image as shown in FIG. 27. Note that there may be two, three, or even five or more images to be placed on one page. If there are two images, a mark is not formed at the central point E (see FIG. 26), but points A, B, C, and D are formed at the four corners. Note that using three or more marks for each image, image "A" in FIG. 27 is corrected using three points x 2, and image "B" is corrected using three points x 2, resulting in better accuracy. Note that "3 points x 2" means that three marks are corrected twice to correct the rectangle.

[0236] As shown in Figures 27 and 28, when four images are simply arranged on one page, it is possible to see how each of images "A" to "D" has been deformed. Marks are created at the four corners of each of images "A" to "D." At this time, deformation tends to occur in the same direction at positions that are close to each other. For example, if the center of the paper is shifted toward the upper left due to expansion or contraction, the lower right of image "A" (on the +X side and the -Y side), the lower left of image "B" (on the -X side and the -Y side), the upper right of image "C" (on the +X side and the +Y side), and the upper left of image "D" (on the -X side and the +Y side) are all close to each other, so a positional shift with the same tendency will occur.

[0237] As shown in FIGS. 29 and 30, if the expansion and contraction at nearby positions tend to be the same, the nearby marks can be made common.

[0238] The mark positions other than those at the four corners vary depending on the imposition. As shown in Figure 31, in the case of four faces, setting (arrangement) can be performed in an area 311 extending in the main scanning direction (X direction) and an area 312 extending in the sub-scanning direction (Y direction).

[0239] In the case of six faces as shown in Fig. 32, settings can be made in area 321 extending in the main scanning direction and areas 322 and 323 extending in the sub-scanning direction. When arranging in three columns, settings are made outside the area in two locations. When arranging in two rows, settings are made outside the area in one location.

[0240] Furthermore, the positions where marks other than the four corners are set (T·L·+ marks) are specified outside of image 313 (area surrounded by dashed lines) or image 324 (area surrounded by dashed lines) of the cutting register marks. The marks are automatically positioned based on the coordinates of the image to be formed on the paper and the marks at the four corners. Images 313 and 324 include the images to be formed on the paper in the job. The images to be formed on the paper include the cutting register marks. The outermost edges of images 313 and 324 are the image boundaries. In the case of automatic positioning, the marks are positioned based on the boundaries of the image to be placed. Note that if the four corners are likely to extend beyond the boundaries, the user may be allowed to specify the mark position on a UI (User Interface) screen. Standardizing the marks reduces the number of times the user needs to specify the cutting area, improving usability and reducing the processing load.

[0241] <Example of operation of liquid ejection device 1b> FIG. 33 is a flowchart showing an example of the correction value calculation operation of the liquid ejection device 1b.

[0242] First, in step S331, the liquid discharger 1b determines a reference position such as a mark position.

[0243] Subsequently, in step S332, correction values for each of the multiple images are calculated based on the marks formed at the reference positions.

[0244] In this way, the liquid ejection device 1b can obtain the correction value.

[0245] FIG. 34 is a flowchart showing an example of detailed operation of calculating the correction value by the liquid ejection device 1b.

[0246] First, in step S341, the liquid discharger 1b sets a mark.

[0247] Subsequently, in step S342, the liquid ejection device 1b adds data corresponding to the marks to the first image data to generate second image data.

[0248] Subsequently, in step S343, the liquid ejection device 1b forms an image on a sheet of paper using the printer 4 based on the second image data.

[0249] Subsequently, in step S344, the liquid ejection device 1b reads the image formed on the paper by the printer 4 using the sensor 425, and calculates the position of the mark on the paper based on the read image data.

[0250] Subsequently, in step S345, the liquid ejection device 1b calculates a correction value based on the position of the mark.

[0251] Subsequently, in step S346, the liquid ejection device 1b stores the calculated correction value in the correction value storage unit 21.

[0252] In this way, the liquid ejection device 1 can calculate and store the correction values.

[0253] The liquid ejection device 1b can improve the accuracy of the image formation position by using the correction values stored in the correction value storage unit 21.

[0254] Here, the main scanning position correction value is a correction value that corrects the drawing position in the direction perpendicular to the image transport direction (main scanning direction), and the sub-scanning position correction value is a correction value that corrects the drawing position in the transport direction (sub-scanning direction).

[0255] The main scanning magnification error correction value is a correction value that corrects the magnification of an image in the main scanning direction, and the sub scanning magnification error correction value is a correction value that corrects the magnification of an image in the sub scanning direction.

[0256] The left side misalignment correction value in the main scanning direction, the right side misalignment correction value in the main scanning direction, the upper side misalignment correction value in the sub-scanning direction, and the lower side misalignment correction value in the sub-scanning direction are correction values that correct distortions in the up, down, left, and right directions of the image (+X direction side, −X direction side, +Y direction side, −Y direction side).

[0257] Partial alignment also uses a test print, position correction settings, and a mechanism for retaining correction values. For partial alignment, correction value data may be stored for each of multiple images on each page of a job, and correction values may also be stored for each paper type. The liquid ejection device 1b can use the stored correction values as the same correction values across multiple jobs and multiple pages.

[0258] Although the preferred embodiments and examples of the present invention have been described in detail above, the present invention is not limited to these embodiments and examples, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

[0259] For example, although the above-described embodiment has been described using a line-scan inkjet image forming apparatus as an example, the present invention is not limited to this. The embodiment can also be applied to a serial-scan inkjet image forming apparatus, and the same effects as those of the above-described liquid ejection apparatus can be obtained.

[0260] The embodiments also include a method for controlling a liquid ejection device. For example, the method for controlling a liquid ejection device is a method for controlling a liquid ejection device that forms an image on a recording medium, and includes the steps of acquiring first image data, generating second image data by adding a predetermined graphic 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 scanned image data of the image formed on the recording medium based on the second image data, and ejecting liquid onto the recording medium based on either the second image data or the third image data. Such a method for controlling a liquid ejection device can achieve the same effects as those of the liquid ejection device described above.

[0261] The embodiment also includes a storage medium. For example, the storage medium stores instructions for causing the liquid ejection device to acquire first image data, generate second image data by adding a predetermined graphic to the first image data, generate third image data by correcting either the first image data or the second image data based on the second image data and scanned image data of an image formed on a recording medium based on the second image data, and eject liquid onto the recording medium based on either the second image data or the third image data. Such a storage medium can achieve the same effects as the liquid ejection device 1 described above.

[0262] Furthermore, each function of the above-described embodiments can be realized by one or more processing circuits. Here, the term "processing circuit" in this specification includes a processor programmed to perform each function by software, such as a processor implemented by an electronic circuit, as well as devices such as an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), and conventional circuit modules designed to perform each of the above-described functions. [Explanation of symbols]

[0263] 1 Liquid discharge device 2 DFE 21 Correction value storage section 3. Image processing unit (an example of an image processing device) 301 First Image Acquisition Unit 302 Second image generation unit 303 Read image acquisition unit 304 Deformation detection unit 305 Correction value acquisition unit 306 Correction Unit 307 Adjustment value storage section 4 Printers 42 Printing Department 423 Ink ejection unit (an example of a liquid ejection unit) 425 Sensor (Example of reading unit) 5 PC 6 Printed matter 95a, 95b Mark (example of a prescribed figure) [Prior art documents] [Patent documents]

[0264] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-210651

Claims

1. A liquid ejection device for forming an image on a recording medium, a first image acquisition unit that acquires first image data; a second image generating unit that generates second image data by adding a predetermined graphic to the first image data; a correction unit that generates third image data by correcting the first image data for each page based on the second image data and read image data of the image formed on the recording medium based on the second image data; a liquid ejection unit that ejects liquid onto the recording medium based on the third image data, When performing double-sided printing in the actual printing of a print job, the liquid ejection device For a first side of the page, the second image data of the first side is generated from the first image data, and further, the third image data of the first side is generated by correcting the second image data of the first side using a correction value obtained based on data after image formation of a second side opposite to the first side by test printing; Regarding the second side, the third image data for the second side is generated by correcting the first image data for the second side based on read image data of the image formed on the recording medium based on the second image data for the first side; liquid is ejected onto the recording medium as the actual printing based on the third image data of the first surface and the third image data of the second surface. Liquid discharge device.

2. A liquid ejection device for forming an image on a recording medium, a first image acquisition unit that acquires first image data; a second image generating unit that generates second image data by adding a predetermined graphic to the first image data; a correction unit that generates third image data by correcting the first image data for each page based on the second image data and read image data of the image formed on the recording medium based on the second image data; a liquid ejection unit that ejects liquid onto the recording medium based on the third image data, When performing double-sided printing in the actual printing of a print job, the liquid ejection device For the first side of the page, the third image data for the first side is generated from the first image data using a correction value acquired based on data after image formation of a second side opposite to the first side by test printing; Regarding the second side, the third image data for the second side is generated by correcting the first image data for the second side based on read image data of the image formed on the recording medium based on the first image data for the first side; liquid is ejected onto the recording medium as the actual printing based on the third image data of the first surface and the third image data of the second surface. Liquid discharge device.

3. The image forming apparatus further includes a reading unit that reads the image formed on the recording medium based on the second image data. The liquid ejection device according to claim 1 or 2.

4. When forming images on both the first surface and the second surface, the liquid ejection unit ejects the liquid onto the first surface based on the first image data or the second image data, and ejects the liquid onto the second surface of the recording medium from which the first surface has been read based on the third image data. The liquid ejection device according to claim 1 .

5. The second side is the side opposite to the first side of the recording medium from which the first side has been read. The liquid ejection device according to claim 4 .

6. The correction unit generates the third image data by correcting the first image data using the correction value calculated by comparing the position of the graphic in the second image data with the position of the graphic in the read image data of the image. The liquid ejection device according to claim 1 .

7. a correction value acquisition unit that acquires the correction value for correcting either the first image data or the second image data based on the deformation amount of the recording medium detected from the second image data and the read image data of the image; The correction unit generates the third image data based on the correction value. The liquid ejection device according to claim 1 .

8. a correction value storage unit for storing the correction value; The correction unit generates the third image data based on the correction value acquired by referring to the correction value storage unit. The liquid ejection device according to claim 7 .

9. When the image is formed on a plurality of pages, the correction value acquisition unit acquires different correction values for each of the plurality of pages. The liquid ejection device according to claim 7 or 8.

10. The correction value acquisition unit acquires the correction value, which differs for each of the plurality of pages, based on a representative pattern formed on the recording medium. The liquid ejection device according to claim 9 .

11. The correction value acquisition unit acquires either the correction value acquired based on the deformation amount or the predetermined correction value. The liquid ejection device according to any one of claims 7 to 10.

12. The liquid ejection device generating the second image data from the first image data as a test print of the print job, and acquiring the correction value for each page of the print job based on the second image data and read image data of the image formed on the recording medium based on the second image data; When performing the actual printing, the third image data in which each of the pages has been corrected is generated using the correction value for each of the pages acquired, and liquid is ejected onto the recording medium based on the third image data. The liquid ejection device according to claim 1 .

13. A method for controlling a liquid ejection device that forms an image on a recording medium, comprising: acquiring first image data; generating second image data by adding a predetermined graphic to the first image data; generating third image data by correcting the first image data for each page based on the second image data and read image data of the image formed on the recording medium based on the second image data; a step of ejecting liquid onto the recording medium based on the third image data; When performing double-sided printing in the actual printing of a print job, the liquid ejection device For a first side of the page, generating the second image data of the first side from the first image data, and further generating the third image data of the first side corrected from the second image data of the first side using a correction value acquired based on data after image formation of a second side opposite to the first side by test printing; generating, for the second side, the third image data for the second side by correcting the first image data for the second side based on read image data of the image formed on the recording medium based on the second image data for the first side; and ejecting liquid onto the recording medium as the actual printing based on the third image data of the first side and the third image data of the second side. A method for controlling a liquid ejection device.

14. A method for controlling a liquid ejection device for forming an image on a recording medium, comprising: acquiring first image data; generating second image data by adding a predetermined graphic to the first image data; generating third image data by correcting the first image data for each page based on the second image data and read image data of the image formed on the recording medium based on the second image data; a step of ejecting liquid onto the recording medium based on the third image data; When performing double-sided printing in the actual printing of a print job, the liquid ejection device generating the third image data for the first side of the page from the first image data using a correction value obtained based on data after image formation of a second side opposite to the first side by test printing; for the second side, generating the third image data for the second side by correcting the first image data for the second side based on read image data of the image formed on the recording medium based on the first image data for the first side; and ejecting liquid onto the recording medium as the actual printing based on the third image data of the first side and the third image data of the second side. A method for controlling a liquid ejection device.

15. acquiring first image data; generating second image data by adding a predetermined graphic to the first image data; generating third image data by correcting the first image data for each page based on the second image data and read image data of an image formed on a recording medium based on the second image data; Discharging liquid onto the recording medium based on the third image data; When performing double-sided printing for the actual printing of a print job, For a first side of the page, the second image data of the first side is generated from the first image data, and further, the third image data of the first side is generated by correcting the second image data of the first side using a correction value obtained based on data after image formation of a second side opposite to the first side by test printing; Regarding the second side, the third image data for the second side is generated by correcting the first image data for the second side based on read image data of an image formed on the recording medium based on the second image data for the first side; liquid is ejected onto the recording medium as the actual printing based on the third image data of the first surface and the third image data of the second surface. A storage medium that stores instructions for causing the liquid ejection device to execute a process.

16. Acquire first image data; generating second image data by adding a predetermined graphic to the first image data; generating third image data by correcting the first image data for each page based on the second image data and read image data of an image formed on a recording medium based on the second image data; Discharging liquid onto the recording medium based on the third image data; When performing double-sided printing for the actual printing of a print job, For the first side of the page, the third image data for the first side is generated from the first image data using a correction value acquired based on data after image formation of a second side opposite to the first side by test printing; Regarding the second side, the third image data for the second side is generated by correcting the first image data for the second side based on read image data of an image formed on the recording medium based on the first image data for the first side; liquid is ejected onto the recording medium as the actual printing based on the third image data of the first surface and the third image data of the second surface. A storage medium that stores instructions for causing the liquid ejection device to execute a process.

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