Liquid ejection device and liquid ejection device adjustment method

Abstract

The present invention provides a liquid ejection device and a method for adjusting the liquid ejection device, which can record the landing position appropriately corrected based on landing position information obtained from a test pattern; a printing device (1) comprises: a nozzle (13) having a plurality of nozzles (131) for ejecting ink droplets toward a printing medium (5); a moving part (20) for moving the nozzle (13) relative to the printing medium (5) in a relative movement direction; and a control part (60) for controlling the nozzle (13) and the moving part (20) to record a test pattern (Tp) on the printing medium (5), and correcting the control of the nozzle (13) and / or the moving part (20) based on a correction value obtained from the test pattern (Tp), thereby performing recording; the test pattern (Tp) has a plurality of blocks (Ptmn) for obtaining a plurality of correction values, the correction values ​​being used to correct the landing position of the ink droplets landing on the printing medium (5) in the relative movement direction.

Description

Technical Field

[0001] The present invention relates to a liquid ejecting device and an adjustment method of the liquid ejecting device. Background Art

[0002] Conventionally, as an example of a liquid ejecting apparatus, there is known an inkjet printer that prints a full-color image by ejecting a plurality of color inks and black ink in the form of ink droplets.

[0003] Patent Document 1 describes a technique for correcting the deviation in the landing position of liquid droplets ejected from such a liquid ejection device. Specifically, the liquid ejection device of Patent Document 1 forms an ejection speed test pattern for determining the ejection speed of liquid ejected in the form of droplets from an ejection portion, and corrects the timing of liquid ejection based on an ejection speed parameter associated with the liquid ejection speed detected from the ejection speed test pattern.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-111037

[0005] However, the landing position deviation correction method described in Patent Document 1 suffers from the following problem: When there are variations in the standard for generating the ejection velocity test pattern used to derive the correction amount, appropriate correction may not be performed. Specifically, for example, when the test pattern is formed by liquid ejected from a specific nozzle with individual differences, or when there are variations in the flatness of the surface of the medium forming the test pattern, an appropriate test pattern cannot be generated, resulting in inadequate correction. Summary of the Invention

[0006] The liquid ejection device of the present invention comprises: a nozzle having a plurality of nozzles for ejecting liquid droplets onto a recording medium; a moving portion for moving the nozzle head relative to the recording medium in a relative moving direction; and a control portion for controlling the nozzle head and the moving portion to record a test pattern on the recording medium, and correcting the control of the nozzle head and / or the moving portion based on a correction value obtained from the test pattern for recording; the test pattern has a plurality of blocks that can be candidates for obtaining a plurality of the correction values, and the correction values ​​are used to correct the landing positions of the liquid droplets in the relative moving direction on the recording medium.

[0007] In the adjustment method of the liquid ejection device of the present invention, the liquid ejection device comprises: a nozzle having a plurality of nozzles for ejecting droplets onto a recording medium; and a moving part for moving the nozzle relative to the recording medium in a relative movement direction; the adjustment method of the liquid ejection device includes: a test pattern recording process for controlling the nozzle and the moving part to record a test pattern on the recording medium, the test pattern having a plurality of blocks capable of obtaining candidates for a plurality of correction values, the correction values ​​being used to correct the landing positions of the droplets in the relative movement direction on the recording medium; a correction value candidate derivation process for deriving a plurality of candidates for the correction values ​​from the test pattern; and a correction value determination process for performing statistical processing on the derived plurality of candidates for the correction values ​​to determine the correction values. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a front view showing the configuration of a printing device as a liquid ejecting device according to the first embodiment.

[0009] Figure 2 This is a block diagram showing the configuration of a printing apparatus as a liquid ejecting apparatus according to the first embodiment.

[0010] Figure 3 It is a schematic diagram showing an example of the arrangement of the nozzle rows as viewed from the bottom surface of the nozzle head.

[0011] Figure 4 This is a conceptual diagram for explaining the elements that cause changes in the landing position of ink droplets on a printing medium.

[0012] Figure 5 This is a conceptual diagram for explaining the elements that cause changes in the landing position of ink droplets on a printing medium.

[0013] Figure 6 This is a conceptual diagram for explaining the elements that cause changes in the landing position of ink droplets on a printing medium.

[0014] Figure 7 This is a conceptual diagram for explaining the elements that cause changes in the landing position of ink droplets on a printing medium.

[0015] Figure 8 This is a conceptual diagram for explaining the elements that cause changes in the landing position of ink droplets on a printing medium.

[0016] Figure 9 A diagram showing an example of a test pattern.

[0017] Figure 10 1 and 2 are diagrams showing examples of images of blocks included in a test pattern.

[0018] Figure 11This is a map that indicates the printing standard of each image in a block using corresponding ideographic characters.

[0019] Figure 12 This is a table showing the printing standards of each image in a block.

[0020] Figure 13 This is a map diagram for explaining the printing standard of information related to the landing positions of ink droplets obtained from the test pattern.

[0021] Figure 14 This is a map diagram for explaining the printing standard of information related to the landing positions of ink droplets obtained from the test pattern.

[0022] Figure 15 This is a map diagram for explaining the printing standard of information related to the landing positions of ink droplets obtained from the test pattern.

[0023] Figure 16 This is a map diagram for explaining the printing standard of information related to the landing positions of ink droplets obtained from the test pattern.

[0024] Figure 17 This is a map diagram for explaining the printing standard of information related to the landing positions of ink droplets obtained from the test pattern.

[0025] Figure 18 This is a map diagram for explaining the printing standard of information related to the landing positions of ink droplets obtained from the test pattern.

[0026] Figure 19 This is a map diagram for explaining the printing standard of information related to the landing positions of ink droplets obtained from the test pattern.

[0027] Figure 20 This is a map diagram for explaining the printing standard of information related to the landing positions of ink droplets obtained from the test pattern.

[0028] Figure 21 This is a map diagram for explaining the printing standard of information related to the landing positions of ink droplets obtained from the test pattern.

[0029] Figure 22 This is a front view showing the configuration of a printing device as a liquid ejecting device according to a second embodiment.

[0030] Figure 23 This is a block diagram showing the configuration of a printing apparatus as a liquid ejecting apparatus according to the second embodiment.

[0031] Figure 24 This is a schematic diagram showing an example of the arrangement of nozzle rows as viewed from the bottom surface of a head included in a printing apparatus as a liquid ejecting apparatus according to a second embodiment.

[0032] Figure 25 This is a diagram showing an example of a test pattern according to the second embodiment.

[0033] Description of Reference Numerals

[0034] 1…Printing device, 5…Printing medium, 10…Ink applying unit, 11…Nozzle unit, 12…Ink supply unit, 13…Nozzle, 14…Nozzle control unit, 15…Gap adjustment unit, 20…Moving unit, 30…Printing control unit, 31…Internal interface, 32…CPU, 33…Memory, 34…Drive control unit, 35…Moving control signal generating circuit, 36…Ejection control signal generating circuit, 37…Drive signal generating circuit, 38…Gap control circuit, 40…Scanning unit, 41…Slide, 42…Guide shaft, 50…Conveyor unit, 51…Supply unit, 52…Storage unit, 53…Conveyor roller, 55…Platen , 60…control unit, 100…printing unit, 110…image processing unit, 111…image control unit, 112…input unit, 113…display unit, 114…storage unit, 115…CPU, 116…ASIC, 117…DSP, 118…memory, 119…interface within the device, 120…universal interface, 131…nozzle, 132…nozzle array, 132A…nozzle array, 132B…nozzle array, 132SA…reference nozzle array, 133…nozzle tip, 134…independent nozzle, 135…nozzle unit, Ptmn…block, Gjk…image, Tp…test pattern, WG…workpiece gap. DETAILED DESCRIPTION

[0035] 1. Implementation Method 1

[0036] Reference Figure 1 、 Figure 2 The configuration of a printing device 1 as a liquid ejecting device according to this embodiment will be described.

[0037] In addition, in the coordinates marked in the drawings, the Z-axis direction is the up and down direction, the +Z direction is the upward direction, the X-axis direction is the front and back direction, the -X direction is the front direction, the Y-axis direction is the left and right direction, the +Y direction is the left direction, and the XY plane is the horizontal plane.

[0038] In addition, this embodiment describes the printing of images, text, symbols, etc. as one form of recording. Recording includes not only printing of images, text, symbols, etc., but also recording of digital information by depositing droplets at desired locations on a recording medium, depositing constituent materials or molding materials on a product, and the like.

[0039] The printing apparatus 1 includes a printing unit 100 and an image processing unit 110 connected to the printing unit 100 .

[0040] The printing unit 100 is an inkjet serial printer that prints a desired image by applying liquid ink to a long print medium 5 wound in a roll as a recording medium based on print data received from the image processing unit 110 .

[0041] The image processing unit 110 includes an image control unit 111, an input unit 112, a display unit 113, a storage unit 114, and other components, and controls a print job to cause the printing unit 100 to perform printing. Furthermore, the image processing unit 110 generates print data for causing the printing unit 100 to print a desired image based on the image data. As a preferred example, the image processing unit 110 is implemented using a personal computer.

[0042] The software running on the image processing unit 110 includes general image processing application software for processing image data to be printed, printer driver software for controlling the printing unit 100 or generating print data for the printing unit 100 to print, and a color conversion lookup table generation program for creating the color conversion lookup table required for generating print data. In the following description, the image processing application software is referred to as the image processing application, and the printer driver software is referred to as the printer driver.

[0043] Here, image data refers to code information such as barcodes, and RGB digital image information including line drawings and text data.

[0044] The image control unit 111 includes a CPU 115, an ASIC 116, a DSP 117, a memory 118, an internal interface 119, a general-purpose interface 120, and other components, and centrally manages the entire printing device 1. The CPU stands for Central Processing Unit, the ASIC stands for Application Specific Integrated Circuit, and the DSP stands for Digital Signal Processor. The input unit 112 is an information input unit that serves as a user interface. Specifically, it includes a keyboard, a mouse pointer, and the like.

[0045] The display unit 113 is an information display unit serving as a user interface, and displays information input from the input unit 112 , images printed by the printing unit 100 , information related to print jobs, and the like under the control of the image control unit 111 .

[0046] The storage unit 114 is a rewritable storage medium such as a hard disk drive or a memory card, and stores programs executed by the image control unit 111 as software executed by the image processing unit 110 , images to be printed, information related to print jobs, and the like.

[0047] Memory 118 is a storage medium that ensures storage of programs executed by CPU 115 or a work area for execution, and is composed of storage elements such as RAM and EEPROM. RAM stands for random access memory, and EEPROM stands for electrically erasable programmable read-only memory.

[0048] The universal interface 120 is an interface capable of connecting to external electronic devices, such as a LAN interface or a USB interface. LAN refers to a local area network, and USB refers to a universal serial bus.

[0049] The printing unit 100 is composed of an ink applying unit 10, a moving unit 20, a print control unit 30, and the like. The printing unit 100 receives print data from the image processing unit 110 and controls the ink applying unit 10 and the moving unit 20 according to the print data through the print control unit 30 to print an image on the print medium 5.

[0050] The print data is image data converted by the image processing application and printer driver included in the image processing unit 110 into data for image formation that can be printed by the printing unit 100 , and includes commands for controlling the printing unit 100 .

[0051] The ink applying section 10 is composed of a head unit 11 , an ink supply section 12 , a gap adjusting section 15 , and the like.

[0052] The moving unit 20 is composed of a scanning unit 40 , a transport unit 50 , and the like.

[0053] The scanner unit 40 is composed of a carriage 41 , a guide shaft 42 , a carriage motor, etc. The carriage motor is not shown in the figure.

[0054] The transport unit 50 is composed of a supply unit 51 , a storage unit 52 , transport rollers 53 , a platen 55 , and the like.

[0055] The head unit 11 includes a head 13 having a plurality of nozzles 131 for ejecting printing ink in the form of ink droplets, and a head control unit 14. The head unit 11 is mounted on a carriage 41. Specifically, the head 13 is mounted on the carriage 41 and reciprocates in the X-axis direction as the carriage 41 moves in the X-axis direction, which is the scanning direction.

[0056] As the ink, an eight-color ink set of cyan C, magenta M, yellow Y, light cyan LC, light magenta LM, light yellow LY, light black LK, and black K is preferably used.

[0057] The ink supply unit 12 includes an ink cartridge and an ink supply path for supplying ink from the ink cartridge to the ejection head 13. The ink cartridge and the ink supply path are not shown in the figure.

[0058] like Figure 3 As shown, the nozzle head 13 is composed of eight nozzle head units 135, namely, nozzle head units 135a to 135h arranged along the X-axis direction.

[0059] Each head unit 135 is composed of eight independent heads 134 , namely, independent heads 134 a to 134 h arranged in the Y-axis direction.

[0060] Each independent nozzle head 134 is composed of four nozzle tips 133, namely nozzle tips 133a to 133d. The nozzle tips 133a to 133d are arranged so that they are staggered in the X-axis direction from the +Y side toward the -Y side. Nozzle tip 133a and nozzle tip 133c are arranged on the -X side of nozzle tip 133b and nozzle tip 133d.

[0061] Each nozzle tip 133 is composed of a nozzle row 132A and a nozzle row 132B that are adjacent to each other in the X-axis direction. The nozzle row 132A is arranged on the +X side of the nozzle row 132B.

[0062] In each nozzle row 132A and each nozzle row 132B, 400 nozzles 131 are arranged along the Y-axis direction, which is the nozzle row direction.

[0063] The nozzles 131 are arranged at predetermined intervals in the entire Y-axis direction when the head units 135 are viewed from the X-axis direction, and are formed to be able to eject ink supplied to the nozzle rows 132 in the −Z direction.

[0064] Each nozzle tip 133 is manufactured using, for example, a silicon wafer as a base material using a MEMS manufacturing process that applies a semiconductor process. The nozzles 131 included in each nozzle tip 133 form a nozzle group having the same or similar ink ejection characteristics. Here, MEMS refers to micro-electromechanical systems (MEMS).

[0065] Light yellow ink LY is supplied to the nozzle row 132A included in the head unit 135 a and the nozzle row 132B included in the head unit 135 h .

[0066] Yellow LY ink is supplied to the nozzle row 132B included in the head unit 135 a and the nozzle row 132A included in the head unit 135 h .

[0067] Magenta M ink is supplied to the nozzle row 132A included in the head unit 135b and the nozzle row 132B included in the head unit 135g.

[0068] Cyan C ink is supplied to the nozzle row 132B included in the head unit 135b and the nozzle row 132A included in the head unit 135g.

[0069] The ink of light black LK is supplied to the nozzle row 132A included in the head unit 135c and the nozzle row 132B included in the head unit 135f.

[0070] Light magenta LM ink is supplied to the nozzle row 132B included in the head unit 135c and the nozzle row 132A included in the head unit 135f.

[0071] Light cyan LC ink is supplied to the nozzle row 132A included in the head unit 135d and the nozzle row 132B included in the head unit 135e.

[0072] Black K ink is supplied to the nozzle row 132B included in the head unit 135d and the nozzle row 132A included in the head unit 135e.

[0073] The ink cartridge, the ink supply path, and the ink supply path to the nozzles 131 that eject the same ink are independently provided for each ink.

[0074] The gap adjustment unit 15 can adjust the distance between the lower surface of the nozzle head 13, that is, the nozzle surface where the nozzles 131 open, and the upper surface of the platen 55 supporting the print medium 5, according to the thickness of the print medium 5. The gap adjustment unit 15 includes a support mechanism that can change the support position of the guide shaft 42 or the support position of the platen 55 in the Z-axis direction under the control of the print control unit 30. Illustration and detailed description of this support mechanism are omitted.

[0075] The moving unit 20 , that is, the scanning unit 40 and the conveying unit 50 , moves the printing medium 5 relative to the nozzle head 13 under the control of the printing control unit 30 .

[0076] The guide shaft 42 extends in the X-axis direction and supports the carriage 41 in a slidable state. Furthermore, the carriage motor serves as the driving source for reciprocating the carriage 41 along the guide shaft 42. Specifically, under the control of the print control unit 30, the scanning unit 40 moves the carriage 41 in the X-axis direction along the guide shaft 42, that is, moves the nozzle head 13 in the X-axis direction along the guide shaft 42. Specifically, the moving unit 20 moves the nozzle head 13 and the print medium 5 relative to each other in a first direction in the X-axis direction that intersects the Y-axis direction, which is the direction of the nozzle array, and in a second direction opposite to the first direction. While the nozzle head 13 of the nozzle unit 11 mounted on the carriage 41 moves in the X-axis direction, it ejects ink droplets onto the print medium 5 supported by the platen 55 under the control of the print control unit 30, thereby forming a plurality of dot arrays along the X-axis direction on the print medium 5.

[0077] In this embodiment, the image control unit 111 and the print control unit 30 constitute a control unit 60 that controls the head 13 and the moving unit 20 based on image data to perform printing.

[0078] The supply unit 51 rotatably supports a reel for rolling up the print medium 5 and delivers the print medium 5 to the transport path. The storage unit 52 rotatably supports a reel for rolling up the print medium 5 and takes up the printed print medium 5 from the transport path.

[0079] The transport roller 53, which is composed of a drive roller that moves the print medium 5 and a driven roller that rotates as the print medium 5 moves, moves the print medium 5 in the Y-axis direction, which is a transport direction intersecting the scanning direction, on the upper surface of the platen 55. The transport roller 53 forms a transport path that transports the print medium 5 from the supply unit 51 to the ink storage unit 52 via the printing area of ​​the ink application unit 10. The printing area is the area on the upper surface of the platen 55 where the print head 13 moves in the X-axis direction.

[0080] The platen 55 is a flat plate that extends in the XY plane direction and supports the print medium 5 from below in the printing area.

[0081] The print control unit 30 includes an internal device interface 31 , a CPU 32 , a memory 33 , a drive control unit 34 , and the like, and controls the print unit 100 .

[0082] The internal interface 31 is connected to the internal interface 119 of the image processing unit 110 , and transmits and receives data between the image processing unit 110 and the printing unit 100 .

[0083] The CPU 32 is a processing unit for controlling the entire printing unit 100 .

[0084] The memory 33 is a storage medium that ensures an area for storing programs executed by the CPU 32 or a work area for the execution, and is composed of a storage element such as a RAM or an EEPROM.

[0085] The CPU 32 controls the ink applying unit 10 and the moving unit 20 via the drive control unit 34 based on the program stored in the memory 33 and the print data received from the image processing unit 110 .

[0086] The drive control unit 34 includes firmware that operates under the control of the CPU 32 , and controls the driving of the head unit 11 , the ink supply unit 12 , the gap adjustment unit 15 of the ink applying unit 10 , the scanning unit 40 of the moving unit 20 , and the transport unit 50 .

[0087] The drive control unit 34 is composed of a drive control circuit including a movement control signal generating circuit 35, an ejection control signal generating circuit 36, a drive signal generating circuit 37, a gap control circuit 38, and the like, as well as a ROM or flash memory that contains firmware for controlling these drive control circuits. The ROM or flash memory that contains the firmware for controlling the drive control circuits is not shown in the figure. Here, ROM refers to read-only memory.

[0088] The movement control signal generating circuit 35 is a circuit that generates signals for controlling the scanning unit 40 and the conveying unit 50 of the moving unit 20 based on the print data and in accordance with instructions from the CPU 32 .

[0089] The ejection control signal generation circuit 36 ​​generates head control signals for selecting nozzles 131 to eject ink, selecting the ejection amount, controlling the ejection timing, etc., based on print data and in accordance with instructions from the CPU 32 .

[0090] The drive signal generating circuit 37 is a circuit that generates a drive signal for driving the pressure generating chamber included in the nozzle head 13 .

[0091] The gap control circuit 38 is a circuit that drives and controls a support mechanism included in the gap adjustment unit 15 , that is, a support mechanism capable of changing the support position of the guide shaft 42 or the support position of the platen 55 in the Z-axis direction.

[0092] Through the above configuration, the printing control unit 30 prints the desired image on the printing medium 5 by repeatedly performing the following actions on the printing medium 5 supplied to the printing area by the supply unit 51 and the conveying roller 53, which refers to: the action of moving the slide 41 supporting the nozzle 13 along the guide shaft 42 in the X-axis direction while ejecting ink droplets from the nozzle 13, and the action of moving the printing medium 5 in the +Y direction intersecting the X-axis direction through the conveying roller 53.

[0093] However, the landing position of ink droplets ejected from nozzles 131 on the print medium 5, i.e., the position of dots formed by the ink droplets, varies depending on factors such as the timing of ink droplet ejection from the nozzle head 13, the position of the nozzle ejecting the ink droplets, the relative movement speed between the nozzle head 13 and the print medium 5, the ink droplet ejection speed, the distance from the nozzle head 13 to the print medium 5, the direction of the ejected ink droplets, and the conveyance accuracy of the print medium 5. The landing position of the ink droplets deviates, and the greater the deviation from the predetermined landing position, the lower the print quality. Therefore, when the landing position deviation is estimated in advance, by pre-assessing the state of this deviation, it is possible to correct the timing of ink droplet ejection and the relative movement between the nozzle head 13 and the print medium 5 to achieve a closer landing position, thereby suppressing a decrease in print quality.

[0094] Reference Figures 4 to 8 The factors that cause the landing position of ink droplets ejected from the nozzles 131 on the printing medium 5 to change will be described in detail.

[0095] In the following description, the ejection velocity of ink droplets ejected from nozzle 131 in the -Z direction is denoted by Vm0, the movement velocity of nozzle head 13, i.e., the relative movement velocity between nozzle 131 and print medium 5 in the X-axis direction, is denoted by Vcr, the flight velocity of ink droplets is denoted by Vm1, and the distance from the tip of nozzle 131 to print medium 5, i.e., the workpiece gaps, are denoted by WG1 and WG2. WG1 and WG2 are two settable workpiece gaps, or two actual workpiece gaps relative to the set workpiece gap WG, and ΔWG = WG2 - WG1 > 0.

[0096] like Figure 4 As shown, the offset δ1 between the ejection position P0 of the ink droplet and the landing position in the X-axis direction is obtained by the following formula.

[0097] δ1=WG1 / Vm0×Vcr

[0098] Therefore, when there are variations in the ejection speed Vm0 of the ink droplets, the moving speed Vcr of the head 13 , and the work gap WG1 , the offset amount δ1 also varies.

[0099] In addition, if Figure 5 As shown in FIG. 2 , the offset amount δ2 of the landing position relative to δ1 when the workpiece gap changes from WG1 to WG2 is obtained by the following formula.

[0100] δ2=WG2 / Vm0×Vcr-WG1 / Vm0×Vcr=ΔWG / Vm0×Vcr

[0101] ΔWG=WG2-WG1 For example, when the actual workpiece gap is WG2 relative to the set value WG1 of the workpiece gap, it can also be regarded as a deviation of the workpiece gap, and the offset δ2 is the offset of the landing position caused by the deviation ΔWG.

[0102] In addition, if Figure 6 As shown in FIG. 2 , the offset δ3 of the landing position relative to δ1 when the ejection angle of the ink droplet deviates by θ in the +X direction can be approximated by the following formula.

[0103] δ3=WG1×tanθ

[0104] The deviation of the ejection angle is caused by, for example, deviation in the installation angle of the individual nozzle heads 134 or the nozzle head unit 135 in the nozzle head 13 , deviation in the molding accuracy of the nozzle tip 133 , and the like.

[0105] In addition, if Figure 7As shown in FIG. 1 , when the installation position of the nozzle head 131 deviates by Δx in the +x direction, the offset δ4 relative to the landing position δ1 is obtained by the following formula.

[0106] δ4=Δx

[0107] If the actually observed offsets δ1-δ4 differ from the expected values ​​of the offsets δ1-δ4, i.e., the design values ​​of the offsets δ1-δ4 determined based on the set conditions, the timing of ink droplet ejection can be corrected to bring the values ​​closer to the predetermined landing position. Correction of ink droplet ejection timing can be achieved, for example, by correcting the rising and falling timings of the waveform of the drive signal generated by the drive signal generation circuit 37.

[0108] In addition, the deviation of the landing position in the Y-axis direction, that is, the conveying direction of the printing medium 5, which is different from the deviation direction of the deviation amounts δ1 to δ4, can be corrected by conveying the printing medium 5 by the conveying unit 50 to be close to the specified landing position.

[0109] The printing device 1 of this embodiment can print a test pattern for observing the landing position of ink droplets on the printing medium 5 and perform printing by correcting the control of the nozzle head 13 and / or the moving unit 20 based on information obtained by analyzing the test pattern.

[0110] Furthermore, when printing a test pattern in the above-mentioned printing method, that is, when printing is performed by ejecting ink droplets while moving the nozzle head 13 in the scanning direction, it is difficult to record the ejection position P0 of the ink droplets in the X-axis direction, which is the starting point of the offset amounts δ1 to δ4, on the printing medium 5. Figure 8 As shown, the ejection position P0 can be determined as the midpoint between the landing position when the ink droplet is ejected at the ejection position P0 during the forward scan, i.e., in the +X direction, and the landing position when the ink droplet is ejected at the ejection position P0 during the return scan, i.e., in the -X direction. Furthermore, the offset δ1 can be obtained as half the distance between these landing positions. The ejection position P0 and offset δ1 determined here assume that the movement speed Vcr of the nozzle 13 during the forward and return scans is equal and that the ejection direction of the ink droplets is not tilted relative to the -Z direction.

[0111] Reference Figures 9 to 12 , the test pattern Tp in this embodiment is described.

[0112] Figure 9The following figure shows test pattern Tpk corresponding to the first row of independent heads 134 in head unit 135a-135h. Here, k = a-h, corresponding to independent heads 134a-134h. Therefore, test pattern Tpk in test pattern Tp consists of eight test patterns Tp (test patterns Tpa-Tph) arranged in the Y-axis direction.

[0113] like Figure 9 As shown, the test pattern Tpk is composed of 32 patches Ptmn = Pt11 to Pt48 with m = 4 rows and n = 8 columns. The patches Ptmn with m = 4 rows correspond to the nozzle tips 133a to 133d of the individual nozzle heads 134 in sequence.

[0114] The four corners of the block Ptmn are surrounded by the block identification mark Mk, as shown in Figure 10 As shown, it is composed of 60 pattern images of images Gjk=G11 to G125 with j=12 rows and k=5 columns.

[0115] Image Gjk is an image whose position can be easily determined by pattern matching based on image recognition, and is line-symmetrical with respect to the relative movement direction between the nozzle 13 and the print medium 5. In this embodiment, the relative movement direction includes not only the scanning direction, i.e., the X-axis direction, but also the transport direction, i.e., the Y-axis direction. Therefore, image Gjk is a point-symmetrical image.

[0116] exist Figure 10 In the example shown, the image Gjk has different shapes for each column, but may also have the same shape.

[0117] The position of each image Gjk determined by pattern matching is the position of a representative point of each image Gjk, for example, the center point of the image Gjk. The determined position of the image Gjk can be processed as a representative value of the landing position information of the ink droplets ejected by one or more nozzles 131 used to print the image Gjk.

[0118] Pattern matching based on image recognition is performed by, for example, capturing a test pattern Tp as image data using a digital camera or scanner, and comparing the grayscale values ​​of the original image data of the block Ptmn serving as the training data with the obtained image data of each block Ptmn. Therefore, the size of each image Gjk is preferably an integer multiple of the resolution of the digital camera or scanner, and the shape of each image Gjk is preferably such that the offset during pattern matching is linearly related to the grayscale value difference.

[0119] Next, refer to Figure 11 、 Figure 12 The standard for printing each image Gjk will be described.

[0120] Figure 11This is a printing standard map that indicates the printing standard of each image Gjk in the block Ptmn using the corresponding ideographic characters a to i.

[0121] exist Figure 12 In the table, the symbols represent ideographic characters corresponding to the printing standards determined by the printing direction, WG, and nozzle array. The printing direction is the direction of movement of the nozzle 13 when printing the corresponding image Gjk, with the +X direction representing the outward movement and the -X direction representing the return movement. In addition, WG indicates whether the set value of the distance from the front end of the nozzle 131 to the printing medium 5 when printing the corresponding image Gjk, that is, the workpiece gap, is WG1 or WG2. The nozzle array indicates whether the nozzle 131 that performs the ejection is a nozzle belonging to the nozzle array 132A of the nozzle tip 133 or a nozzle belonging to the nozzle array 132B. In addition, although the nozzle array of the symbol b is set to SA, this means that printing is performed using the nozzles 131 included in one nozzle array 132A serving as a reference among the 256 nozzle arrays 132A and the 256 nozzle arrays 132B possessed by the nozzle head 13. In the following description, the nozzle array 132A serving as a reference will be referred to as the reference nozzle array 132SA. The reference nozzle row 132SA is selected from the nozzle row 132A arranged approximately near the center of the nozzle head 13 in a plan view.

[0122] In addition, Figure 11 In the map of the printing standard shown, even if the same symbol is printed based on the printing of the symbol shown at different positions in the Y-axis direction, it is printed by different nozzles 131 in the Y-axis direction.

[0123] In addition, the head unit 135 that prints each block Ptmn is as follows.

[0124] The blocks Ptmn of the first column, ie, blocks Pt11 , Pt21 , Pt31 , and Pt41 , are printed by the head unit 135 a in addition to the image Gjk printed based on the printing standard of symbol b.

[0125] The blocks Ptmn of the second column, namely, blocks Pt13, Pt23, Pt33, and Pt43, are printed by the head unit 135b in addition to the image Gjk printed based on the printing standard of symbol b.

[0126] The blocks Ptmn of the third column, namely, blocks Pt13, Pt23, Pt33, and Pt43, are printed by the head unit 135c in addition to the image Gjk printed based on the printing standard of symbol b.

[0127] The blocks Ptmn of the fourth column, ie, blocks Pt14 , Pt24 , Pt34 , and Pt44 , are printed by the head unit 135 d in addition to the image Gjk printed based on the printing standard of symbol b.

[0128] The blocks Ptmn of the fifth column, namely, blocks Pt15 , Pt25 , Pt35 , and Pt45 , are printed by the head unit 135 e in addition to the image Gjk printed based on the printing standard of symbol b.

[0129] The blocks Ptmn in the sixth column, ie, blocks Pt16 , Pt26 , Pt36 , and Pt46 , are printed by the head unit 135 f in addition to the image Gjk printed based on the printing standard of symbol b.

[0130] The blocks Ptmn of the seventh column, ie, blocks Pt17, Pt27, Pt37, and Pt47, are printed by the head unit 135g in addition to the image Gjk printed based on the printing standard of symbol b.

[0131] The blocks Ptmn in the eighth column, ie, blocks Pt18 , Pt28 , Pt38 , and Pt48 , are printed by the head unit 135 h in addition to the image Gjk printed based on the printing standard of symbol b.

[0132] Next, refer to Figures 13 to 21 , the information on the landing position shift obtained by analyzing the test pattern Tp described above will be described.

[0133] First, according to Figure 13 The images Gjk = G11 to G15 (denoted by symbol a) and Gjk = G21 to G25 (denoted by symbol b) are enclosed by a bold line. The amount of landing position shift between the eight head units 135, including the nozzles 131 that print these images Gjk, is detected. Specifically, the images Gjk = G21 to G25 (denoted by symbol b) are images printed by the nozzles 131 included in the reference nozzle array 132SA. Furthermore, the images Gjk = G11 to G15 (denoted by symbol a) adjacent to the +Y side of these images are printed using the same printing standard as the images Gjk = G21 to G25 (denoted by symbol b), namely, with the same printing direction, the same workpiece gap, and the same nozzle array on the A side. These images are printed by the nozzles 131 included in each of the eight head units 135.

[0134] Therefore, it is possible to detect the amount of deviation of the landing position of ink ejected from the nozzles 131 included in the eight head units 135 relative to the landing position of ink ejected from the nozzles 131 included in the reference nozzle array 132SA.

[0135] Here, the reference nozzle row 132SA can be considered the first nozzle row, and the nozzle rows 132A included in each of the seven head units 135 other than the head unit 135 having the reference nozzle row 132SA can be considered the second nozzle row. Specifically, the nozzle head 13 includes a first nozzle row and a second nozzle row in which the nozzles 131 are arranged in a nozzle row direction, and the plurality of blocks Ptmn include a plurality of blocks Ptmn from which a plurality of offset amounts can be derived, the offset amounts being the relative displacement between the landing positions of ink droplets ejected from the nozzles 131 of the first nozzle row and the landing positions of ink droplets ejected from the nozzles 131 of the second nozzle row.

[0136] Alternatively, the head unit 135 having the reference nozzle array 132SA may be referred to as the first nozzle unit, and the other head units 135 may be referred to as the second nozzle unit. Specifically, the head 13 includes a first nozzle unit and a second nozzle unit. The first nozzle unit is composed of a plurality of nozzle arrays having the nozzles 131 arranged therein, and the second nozzle unit is different from the first nozzle unit and is composed of a plurality of nozzle arrays having the nozzles 131 arranged therein. The first nozzle array is included in the first nozzle unit, and the second nozzle array is included in the second nozzle unit.

[0137] In addition, the information on the landing position offset between the nozzle units 135 can be obtained as difference information from the reference nozzle array 132SA, and 5 / block Ptmn×4 blocks Ptmn=20 can be obtained for each independent nozzle 134, that is, 20×8 independent nozzles 134=160 can be obtained for each nozzle unit 135.

[0138] Based on the information of the 160 landing position deviations obtained, correction values ​​can be derived for suppressing landing position deviations among the eight head units 135. For example, as described above, landing position deviations in the X-axis direction can be suppressed by correcting the timing of ejecting ink droplets.

[0139] The correction value for ejection timing corresponds to each of the 160 values ​​of landing position offset information obtained, and can be derived as a candidate correction value. Specifically, the test pattern Tp includes multiple patches Ptmn that can yield multiple candidate correction values. These correction values ​​are used to correct the landing position of ink droplets on the print medium 5 in the relative movement direction.

[0140] As a method of deriving a correction value for correcting the timing of ejecting ink droplets for each head unit 135 , various statistical processing methods can be utilized.

[0141] For example, the information on 160 landing position deviations obtained is averaged, and a correction value for the ejection timing corresponding to the obtained average value is derived.

[0142] Alternatively, if the 160 pieces of landing position offset information obtained include information with outliers, the outliers are removed and the average value is calculated. This is then used as a correction value for the ejection timing corresponding to the average value. Outliers are values ​​not detected during normal printing, and are detected due to, for example, abnormalities in the position or shape of the patch Ptmn caused by wrinkles or lifting of the print medium 5 or ink clogging of the nozzle 131.

[0143] Alternatively, a method may be adopted in which the median or mode of the 160 landing position deviation values ​​is extracted as a representative value, and a correction value corresponding to the representative value is used as a correction value for the ejection timing.

[0144] Alternatively, instead of correcting the ink droplet ejection timing for each head unit 135, the ink droplet ejection timing may be corrected for each nozzle tip 133. In this case, the average or median value of the five landing position offsets obtained from the combination of the five groups Ptmn of the same nozzle tip 133 is used as a representative value of the offset amount.

[0145] Here, when the present embodiment is understood as a method for adjusting a printing device 1 having a nozzle 13 having a plurality of nozzles 131 for ejecting ink droplets toward a printing medium 5 and a moving portion 20 for moving the nozzle 13 relative to the printing medium 5 in a relative movement direction, the method for adjusting the printing device 1 includes: a test pattern recording process of controlling the nozzle 13 and the moving portion 20 to print a test pattern Tp having a plurality of blocks Ptmn on the printing medium 5, the plurality of blocks Ptmn being capable of obtaining a plurality of correction value candidates for correcting the landing positions of ink droplets landing on the printing medium 5 in the relative movement direction; a correction value candidate derivation process of deriving a plurality of correction value candidates from the test pattern Tp; and a correction value determination process of performing statistical processing on the derived plurality of correction value candidates to determine the correction value.

[0146] In addition, as described above, the block Ptmn is a pattern that is line-symmetrical in the relative movement direction of the printing position of the printed block Ptmn, which can be detected by pattern matching, and the difference information between the printing positions of two blocks Ptmn among the multiple blocks Ptmn is used to derive each of the multiple correction value candidates.

[0147] In the test pattern recording process, as shown by the image Gjk=G21~G25 represented by the symbol b and the image Gjk=G11~G15 represented by the symbol a, and as also described in the following description, the two blocks Ptmn for obtaining the difference information are printed adjacent to each other in the relative movement direction for detecting the landing position deviation, that is, the direction intersecting the X-axis direction, that is, the Y-axis direction.

[0148] Then, you can Figure 14 The images Gjk=G31, G33, G35, G72, G74 represented by the symbol c surrounded by the thick line, and the images Gjk=G41, G43, G45, G82, G84 represented by the symbol d, are calculated for each nozzle unit 135 respectively for the estimated value of the ink droplet ejection velocity Vm0 of the nozzle 131 that prints these images Gjk.

[0149] Specifically, the printing of images Gjk = G31, G33, G35, G72, and G74, indicated by reference numeral c, and the printing of images Gjk = G41, G43, G45, G82, and G84, adjacent to these images in the Y-axis direction, indicated by reference numeral d, differ only in the workpiece gap WG. The printing direction is the -X direction, and the nozzle array is nozzle array 132A.

[0150] like Figure 5 As shown,

[0151] Since δ2=(WG2-WG1) / VmO×Vcr,

[0152] therefore,

[0153] Vm0=(WG2-WG1) / δ2×Vcr,

[0154] When the workpiece gaps WG1 and WG2 and the moving speed Vcr of the nozzle 13 are known values, the ink droplet ejection speed Vm0 of the nozzle 131 can be obtained as an estimated value by detecting δ2 based on the image Gjk=G31, G33, G35, G72, G74 represented by symbol c and the image Gjk=G41, G43, G45, G82, G84 represented by symbol d. Based on the obtained ink droplet ejection speed Vm0, for example, when the workpiece gap WG is changed or when a deviation is detected in the workpiece gap WG, Figure 5 As shown,

[0155] δ2=ΔWG / Vm0×Vcr,

[0156] Therefore, δ2 can be derived, and correction values ​​such as the ink droplet ejection timing corresponding to δ2 can be derived.

[0157] 160 δ2 can be obtained from the test pattern Tp for each head unit 135. As a method of deriving the ink droplet ejection velocity Vm0 of the nozzle 131 from the 160 δ2, various statistical processing methods can be used, similar to the derivation of the correction value described above.

[0158] Then, you can Figure 15The images Gjk=G41, G43, G45, G82, G84 represented by the symbol d surrounded by the thick line and the images Gjk=G51, G53, G55, G92, G94 represented by the symbol a, are calculated as estimated values ​​for each nozzle unit 135, namely, the distance from the front end of the nozzle 131 that prints these images Gjk to the printing medium 5, that is, the workpiece gap WG.

[0159] Specifically, the images Gjk=G41, G43, G45, G82, and G84 represented by symbol d and the images Gjk=G51, G53, G55, G92, and G94 represented by symbol a adjacent to these images in the Y-axis direction differ only in the printing direction.

[0160] Assuming that the ejection velocity Vm0 of the ink droplets and the movement velocity Vcr of the nozzle 13 are known values, the movement velocity Vcr of the nozzle 13 in the outward and return strokes are equal, and the ejection direction of the ink droplets is not tilted relative to the -Z direction, as shown in FIG. Figure 8 As shown,

[0161] δ1×2=WG1 / Vm0×Vcr×2

[0162] therefore,

[0163] WG1=(δ1×2)×Vm0 / Vcr / 2,

[0164] By detecting δ1×2 based on the image Gjk=G41, G43, G45, G82, G84 represented by symbol d and the image Gjk=G51, G53, G55, G92, G94 represented by symbol a, WG1 can be obtained. In other words, the actual workpiece gap WG1 can be obtained for the set workpiece gap WG. Therefore, when a deviation is detected in the workpiece gap WG, as shown in FIG. Figure 5 As shown,

[0165] δ2=ΔWG / Vm0×Vcr,

[0166] Therefore, δ2 can be derived, and also, a correction value corresponding to δ2 can be derived.

[0167] 160 values ​​of δ1×2 can be obtained from the test pattern Tp for each head unit 135. As a method of deriving the workpiece gap WG1 from the 160 values ​​of δ1×2, various statistical processing methods can be used, similar to the derivation of the correction value described above.

[0168] However, as described above, the images Gjk = G41, G43, G45, G82, and G84, represented by symbol d, and the images Gjk = G51, G53, G55, G92, and G94, adjacent to these images in the Y-axis direction, represented by symbol a, differ only in their printing directions. Specifically, the movement unit 20 moves the nozzle head 13 and the print medium 5 relative to each other in a first direction intersecting the nozzle array direction and in a second direction opposite to the first direction. The plurality of patches Ptmn includes patches Ptmn printed while the nozzle head 13 moves relative to the print medium 5 in the first direction and patches Ptmn printed while the nozzle head 13 moves relative to the print medium 5 in the second direction.

[0169] Then, you can Figure 16 The images Gjk=G51, G53, G55, G92, G94 represented by the symbol a surrounded by the thick line and the images Gjk=G61, G63, G65, G102, G104 represented by the symbol e, the estimated value of the ink droplet ejection speed Vm0 of the nozzle 131 that prints these images Gjk is calculated for each nozzle unit 135.

[0170] With reference Figure 14 The only difference in the description is the position of the nozzle 131 of the printed image Gjk and the combination of the printing direction and the two workpiece gaps WG. However, since the information of the ink droplet ejection velocity Vm0 derived under different conditions can be obtained in the same nozzle array 132A, a more effective correction value can be derived.

[0171] Then, you can Figure 17 The images Gjk=G32, G34, G71, G73, G75 represented by the symbol f surrounded by the thick line and the images Gjk=G42, G44, G81, G83, G85 represented by the symbol g, the estimated value of the ink droplet ejection velocity Vm0 of the nozzle 131 that prints these images Gjk is calculated for each nozzle unit 135.

[0172] With reference Figure 14 The difference in the description is that the nozzle column including the nozzle 131 for printing the image Gjk is changed from the nozzle column 132A to the nozzle column 132B. However, since the information of the ejection velocity Vm0 of the ink droplets ejected by the nozzles 131 of different nozzle columns can be obtained, a more effective correction value can be derived.

[0173] Here, when printing is performed by the nozzles 131 included in the same nozzle row 132A, Figure 14When the image Gjk=G31, G33, G35, G72, G74 represented by the symbol c and the image Gjk=G41, G43, G45, G82, G84 represented by the symbol d are shown, the nozzle 131 can be used as the first nozzle and the nozzle column 132A can be used as the first nozzle column.

[0174] In addition, when printing by the nozzles 131 included in the same nozzle array 132B, Figure 17 When the image Gjk=G32, G34, G71, G73, G75 represented by the symbol f and the image Gjk=G42, G44, G81, G83, G85 represented by the symbol g are shown, the nozzle 131 can be used as the second nozzle and the nozzle column 132B can be used as the second nozzle column.

[0175] That is, the plurality of blocks Ptmn include a plurality of blocks Ptmn from which a plurality of estimated values ​​can be derived, including a plurality of estimated values ​​of the ejection speed of ink droplets ejected from the first nozzle of the first nozzle row and a plurality of estimated values ​​of the ejection speed of ink droplets ejected from the second nozzle of the second nozzle row.

[0176] Here, when printing is performed by the nozzles 131 included in the same nozzle row 132A, Figure 14 When the image Gjk represented by the symbol c shown in the figure is G31, G33, G35, the nozzle 131 can be used as the first nozzle, and the nozzle 131 different from the first nozzle included in the same nozzle array 132A including the first nozzle can be used to print the image. Figure 14 When the image Gjk represented by the symbol c shown is G72 or G74, the nozzle 131 can be used as the third nozzle.

[0177] In addition, when printing by the nozzles 131 included in the same nozzle array 132B, Figure 17 When the image Gjk=G32, G34 represented by the symbol f shown in the figure, the nozzle 131 can be used as the second nozzle, and the nozzle 131 different from the second nozzle included in the same nozzle array 132B including the second nozzle can be used to print the image. Figure 17 When the image Gjk represented by the symbol f shown is G71, G73, G75, the nozzle 131 can be used as the fourth nozzle.

[0178] That is, the plurality of blocks Ptmn include a plurality of blocks Ptmn from which a plurality of estimated values ​​can be derived, including a plurality of estimated values ​​of the ejection speed of ink droplets ejected from the third nozzle of the first nozzle column and a plurality of estimated values ​​of the ejection speed of ink droplets ejected from the fourth nozzle of the second nozzle column.

[0179] Then, you can Figure 18The images Gjk=G42, G44, G81, G83, G85 represented by the symbol g surrounded by the thick line and the images Gjk=G52, G54, G91, G93, G95 represented by the symbol h, the distance from the front end of the nozzle 131 that prints these images Gjk to the printing medium 5, that is, the workpiece gap WG is calculated as an estimated value for each nozzle unit 135.

[0180] With reference Figure 15 The difference in the description is that the nozzle array including the nozzle 131 for printing the image Gjk is changed from the nozzle array 132A to the nozzle array 132B. However, since the estimated value of the distance from the front end of the nozzle 131 of the different nozzle arrays to the printing medium 5, that is, the workpiece gap WG, can be obtained, a more effective correction value can be derived.

[0181] Here, when printing is performed by the nozzles 131 included in the same nozzle row 132A, Figure 15 When the image represented by the symbol d is Gjk=G41, G43, G45, G82, G84 and the image represented by the symbol a is Gjk=G51, G53, G55, G92, G94, the nozzle 131 can be used as the first nozzle and the nozzle column 132A can be used as the first nozzle column.

[0182] In addition, when printing by the nozzles 131 included in the same nozzle array 132B, Figure 18 When the image Gjk=G42, G44, G81, G83, G85 represented by the symbol g and the image Gjk=G52, G54, G91, G93, G95 represented by the symbol h are shown, the nozzle 131 can be used as the second nozzle and the nozzle column 132B can be used as the second nozzle column.

[0183] That is, the plurality of blocks Ptmn include a plurality of blocks Ptmn from which a plurality of estimated values ​​can be derived, the plurality of estimated values ​​including a plurality of estimated values ​​of the distance from the first nozzle of the first nozzle row to the printing medium 5 and a plurality of estimated values ​​of the distance from the second nozzle of the second nozzle row to the printing medium 5 .

[0184] Here, when printing is performed by the nozzles 131 included in the same nozzle row 132A, Figure 15 When the image Gjk represented by the symbol d shown in the figure is G41, G43, or G45, the nozzle 131 can be used as the first nozzle, and a nozzle 131 different from the first nozzle included in the same nozzle array 132A including the first nozzle can be used to print the image. Figure 15 When the image Gjk represented by the symbol d shown is G82 or G84, the nozzle 131 can be used as the third nozzle.

[0185] In addition, when printing by the nozzles 131 included in the same nozzle array 132B, Figure 18 When the image Gjk=G42, G44 represented by the symbol g shown in the figure, the nozzle 131 can be used as the second nozzle, and the nozzle 131 different from the second nozzle included in the same nozzle array 132B including the second nozzle can be used to print the image. Figure 18 When the image Gjk represented by the symbol g shown is G81, G83, G85, the nozzle 131 can be used as the fourth nozzle.

[0186] That is, the plurality of blocks Ptmn include a plurality of blocks Ptmn from which a plurality of estimation values ​​can be derived, the plurality of estimation values ​​including a plurality of estimation values ​​of the distance from the third nozzle of the first nozzle row to the printing medium 5 and a plurality of estimation values ​​of the distance from the fourth nozzle of the second nozzle row to the printing medium 5.

[0187] Then, you can Figure 19 The images Gjk=G52, G54, G91, G93, G95 represented by the symbol h surrounded by the thick line and the images Gjk=G62, G64, G101, G103, G105 represented by the symbol i, the estimated value of the ink droplet ejection speed Vm0 of the nozzle 131 that prints these images Gjk is calculated for each nozzle unit 135.

[0188] With reference Figure 16 The difference in the description is that the nozzle column including the nozzle 131 for printing the image Gjk is changed from the nozzle column 132A to the nozzle column 132B. However, since the information of the ejection velocity Vm0 of the ink droplets ejected by the nozzles 131 of different nozzle columns can be obtained, a more effective correction value can be derived.

[0189] Then, you can Figure 20 The images Gjk=Glll, G112, G113, G114, G115 represented by the symbol h surrounded by the thick line and the images Gjk=G121, G122, G123, G124, G125 represented by the symbol a are detected for each nozzle unit 135, and the offset of the landing position between the nozzle columns including the nozzles 131 that print these images Gjk is detected respectively.

[0190] Specifically, images Gjk = G111, G112, G113, G114, and G115, denoted by reference numeral h, are images printed by nozzles 131 included in nozzle array 132B. Furthermore, images Gjk = G121, G122, G123, G1224, and G125, denoted by reference numeral a and adjacent to the -Y side of these images, are images printed by nozzles 131 included in nozzle array 132A. Other than this, the images are printed using the same printing standard, that is, the same printing direction and the same workpiece gap.

[0191] Therefore, the amount of displacement between the landing position of ink ejected from nozzles 131 included in nozzle row 132B and the landing position of ink ejected from nozzles 131 included in nozzle row 132A can be detected for each head unit 135. Furthermore, correction values ​​for ink droplet ejection timing and the like can be derived based on the obtained displacement.

[0192] That is, here, when the nozzle column 132A is regarded as the first nozzle column and the nozzle column 132B is regarded as the second nozzle column, the nozzle head 13 has a first nozzle column and a second nozzle column in which the nozzles 131 are arranged along the nozzle column direction, and the multiple blocks Ptmn include multiple blocks Ptmn that can derive multiple offset amounts, which are the offsets in the relative movement direction between the landing positions of the ink droplets ejected from the nozzles 131 of the first nozzle column and the landing positions of the ink droplets ejected from the nozzles 131 of the second nozzle column.

[0193] Then, you can Figure 21 In the two blocks Ptmn arranged above and below, the images Gjk=G121~G125 represented by the symbol a surrounded by a thick line in the upper block Ptmn and the images Gjk=G11~G15 represented by the symbol a surrounded by a thick line in the lower block Ptmn, the offset amount of the landing position offset between the nozzle columns including the nozzles 131 that print these images Gjk is detected for each nozzle unit 135.

[0194] Specifically, for example, when the image Gjk=G121~G125 represented by the symbol a surrounded by a thick line in the upper block Ptmn is printed by the nozzle 131 belonging to the nozzle tip 133a, and the image Gjk=G11~G15 represented by the symbol a surrounded by a thick line in the lower block Ptmn is printed by the nozzle 131 belonging to the nozzle tip 133b, the offset amount of the landing position offset between the nozzle tip 133a and the nozzle tip 133b can be detected separately for each nozzle unit 135.

[0195] That is, here, when the nozzle column included in the nozzle tip 133a is regarded as the first nozzle column and the nozzle column included in the nozzle tip 133b is regarded as the second nozzle column, the nozzle head 13 has a first nozzle column and a second nozzle column in which the nozzles 131 are arranged along the nozzle column direction, and the multiple blocks Ptmn include multiple blocks Ptmn that can derive multiple offset amounts, which are the offsets in the relative movement direction between the landing positions of the ink droplets ejected from the nozzles 131 of the first nozzle column and the landing positions of the ink droplets ejected from the nozzles 131 of the second nozzle column.

[0196] According to this embodiment, the following effects can be obtained.

[0197] The printing device 1 includes a print head 13 having multiple nozzles 131 for ejecting ink droplets onto a print medium 5; a moving unit 20 for moving the print head 13 relative to the print medium 5 in a relative movement direction; and a control unit 60 for controlling the print head 13 and the moving unit 20 to print a test pattern Tp on the print medium 5. Printing is performed by correcting the control of the print head 13 and / or the moving unit 20 based on correction values ​​obtained from the test pattern Tp. The test pattern Tp includes multiple blocks Ptmn from which multiple correction value candidates can be obtained. These correction values ​​are used to correct the landing positions of ink droplets on the print medium 5 in the relative movement direction. Because multiple correction value candidates for correcting the landing positions are available, statistical processing of the multiple correction value candidates allows for the derivation of appropriate correction values. For example, even if the multiple correction value candidates include unique data with an offset, statistical processing, such as by eliminating the unique data, allows the derivation of appropriate correction value candidates without the offset. Consequently, printing can be performed with the landing positions appropriately corrected.

[0198] The nozzle head 13 has a first nozzle array and a second nozzle array arranged along the nozzle array direction, as shown in FIG. Figure 20 As described, the plurality of blocks Ptmn include a plurality of blocks Ptmn capable of deriving a plurality of offsets in the relative movement direction between the landing positions of ink droplets ejected from the nozzles 131 of the first nozzle array and the landing positions of ink droplets ejected from the nozzles 131 of the second nozzle array.

[0199] By comparing the ideal offset between the landing positions of ink droplets ejected from the nozzles 131 of the first nozzle row and the landing positions of ink droplets ejected from the nozzles 131 of the second nozzle row with the offset obtained based on the test pattern Tp, correction can be performed to achieve printing with the ideal offset. For example, if the ideal offset is zero, appropriate correction can be performed by correcting the control of the printhead 13 and / or the moving unit 20 so that the offset obtained based on the test pattern Tp becomes zero.

[0200] In this embodiment, since multiple offset data can be obtained from the test pattern Tp, even if the obtained multiple offset data include unique data with an offset, by performing statistical processing such as excluding the unique data, correction values ​​can be derived from multiple appropriate offset data without an offset. This allows printing with the impact position appropriately corrected.

[0201] As reference Figure 14 and Figure 17As described, the plurality of blocks Ptmn include a plurality of blocks Ptmn from which estimated values ​​can be derived, including a plurality of estimated values ​​of the ejection velocity Vm0 of ink droplets ejected from the first nozzle of the first nozzle row and a plurality of estimated values ​​of the ejection velocity Vm0 of ink droplets ejected from the second nozzle of the second nozzle row.

[0202] By calculating the ejection velocity Vm0 of the ejected ink droplets in advance, when the relative movement speed between the nozzle 13 and the printing medium 5, or the setting of the distance from the nozzle 13 to the printing medium 5 is changed, the changed landing position can be estimated, and the corresponding landing position can be properly corrected.

[0203] In this embodiment, the multiple candidate blocks Ptmn used to obtain correction values ​​include multiple blocks Ptmn from which estimated values ​​can be derived. These correction values ​​are used to correct the landing position of ink droplets. These estimated values ​​include multiple estimated values ​​of the ejection velocity Vm0 of ink droplets ejected from the first nozzle of the first nozzle row and multiple estimated values ​​of the ejection velocity Vm0 of ink droplets ejected from the second nozzle of the second nozzle row. Therefore, even if the multiple estimated values ​​include biased unique data, the estimated value of the ejection velocity Vm0 can be derived from multiple appropriate, unbiased estimated values ​​of the ejection velocity Vm0 by performing statistical processing, such as eliminating the unique data. Furthermore, estimated values ​​of the ejection velocity Vm0 can be derived separately for the first nozzle of the first nozzle row and the second nozzle of the second nozzle row. Therefore, the landing position can be appropriately corrected based on the estimated values ​​of the ejection velocity Vm0 of the ink droplets. For example, even when the relative movement speed between the head 13 and the print medium 5 or the distance setting from the head 13 to the print medium 5 is changed, the changed landing position can be appropriately corrected.

[0204] As reference Figure 14 and Figure 17 As described, the plurality of blocks Ptmn include a plurality of blocks Ptmn from which a plurality of estimation values ​​can be derived, the plurality of estimation values ​​including a plurality of estimation values ​​of the ejection velocity Vm0 of the ink droplets ejected from the first nozzle and the third nozzle of the first nozzle column and a plurality of estimation values ​​of the ejection velocity Vm0 of the ink droplets ejected from the second nozzle and the fourth nozzle of the second nozzle column.

[0205] Even for the same nozzle row, differences may be observed in the estimated values ​​of the ejection velocity Vm0 derived depending on the nozzles 131. Since the estimated values ​​of the ejection velocity Vm0 of the different nozzles 131 are appropriately derived in the first nozzle row and the second nozzle row, if there are individual differences among the nozzles 131 within the same nozzle row, their influence can be eliminated or reduced by, for example, calculating the average of these differences.

[0206] As reference Figure 15 and Figure 18 As described, the multiple blocks Ptmn include multiple blocks Ptmn from which estimated values ​​can be derived, the estimated values ​​including multiple estimated values ​​of the distance from the first nozzle of the first nozzle row to the printing medium 5, that is, the workpiece gap WG, and multiple estimated values ​​of the distance from the second nozzle of the second nozzle row to the printing medium 5.

[0207] When ejecting ink droplets while moving the nozzle head 13 relative to the print medium 5, the impact position of the ink droplets changes as the distance from the nozzle 131 to the print medium 5 changes. Therefore, by appropriately calculating an estimated value for the distance from the nozzle 131 to the print medium 5, the impact position can be appropriately corrected.

[0208] In this embodiment, the multiple candidate blocks Ptmn used to obtain correction values ​​include multiple blocks Ptmn from which estimated values ​​can be derived. These correction values ​​are used to correct the landing position of ink drops. These estimated values ​​include multiple estimated values ​​for the distance from the first nozzle of the first nozzle row to the print medium 5 and multiple estimated values ​​for the distance from the second nozzle of the second nozzle row to the print medium 5. Therefore, even if the multiple estimated values ​​include biased unique data, statistical processing, such as eliminating the unique data, can be performed to derive appropriate estimated values ​​for the distance from the nozzle 131 to the print medium 5 from multiple appropriate, unbiased estimated values. Furthermore, estimated values ​​for the distance from the first nozzle of the first nozzle row and the second nozzle of the second nozzle row can be derived separately for each nozzle 131 to the print medium 5. This allows appropriate correction of the landing position based on the estimated values ​​for the distance from the nozzle 131 to the print medium 5. For example, even if the relative movement speed between the nozzle head 13 and the print medium 5 or the distance setting between the nozzle head 13 and the print medium 5 is changed, appropriate correction can be made to the changing landing position.

[0209] As reference Figure 15 and Figure 18 As described, the plurality of blocks Ptmn include a plurality of blocks Ptmn from which a plurality of estimated values ​​can be derived, the plurality of estimated values ​​including a plurality of estimated values ​​of the distance from the first nozzle and the third nozzle of the first nozzle row to the printing medium 5, that is, a plurality of estimated values ​​of the workpiece gap WG, and a plurality of estimated values ​​of the distance from the second nozzle and the fourth nozzle of the second nozzle row to the printing medium 5.

[0210] Even for the same nozzle array, differences may occur in the estimated values ​​derived as the distance from the nozzle 131 to the print medium 5 depending on the nozzle 131. Since the estimated values ​​of the distance from the different nozzles 131 to the print medium 5 are appropriately derived in the first nozzle array and the second nozzle array, even if differences occur within the same nozzle array, their influence can be eliminated or reduced by, for example, averaging the differences.

[0211] As reference Figure 13 As described, the printhead 13 includes a first nozzle unit and a second nozzle unit. The first nozzle unit is composed of multiple nozzle rows with nozzles 131 arranged in an array, i.e., the printhead unit 135 having the reference nozzle row 132SA. The second nozzle unit is different from the first nozzle unit and is composed of multiple nozzle rows with nozzles 131 arranged in an array, i.e., the printhead unit 135 other than the first nozzle unit. The first nozzle row is included in the first nozzle unit, and the second nozzle row is included in the second nozzle unit. Therefore, it is possible to appropriately correct the landing position deviation between the first and second nozzle units.

[0212] The moving unit 20 moves the nozzle head 13 and the print medium 5 relative to each other in a first direction intersecting the nozzle array direction and in a second direction opposite to the first direction. The plurality of patches Ptmn include patches Ptmn printed while the nozzle head 13 moves relative to the print medium 5 in the first direction, and patches Ptmn printed while the nozzle head 13 moves relative to the print medium 5 in the second direction. Therefore, printing can be performed with appropriate correction applied to landing position deviations that occur during relative movement in both the first and second directions.

[0213] The adjustment method of the printing device 1 includes: a test pattern Tp recording process, controlling the nozzle 13 and the moving part 20 to print a test pattern Tp having multiple blocks Ptmn on the printing medium 5, and the multiple blocks Ptmn can obtain multiple correction value candidates for correcting the landing position of the ink droplets landing on the printing medium 5 in the relative movement direction; a correction value candidate derivation process, deriving multiple correction value candidates from the test pattern Tp; and a correction value determination process, performing statistical processing on the derived multiple correction value candidates to determine the correction value.

[0214] By statistically processing the derived multiple correction value candidates, appropriate correction values ​​can be derived. For example, even if the derived multiple correction value candidates contain biased unique data, statistical processing, such as by excluding the unique data, allows correction values ​​to be derived from appropriate correction value candidates without bias. This enables printing with appropriately corrected impact positions.

[0215] The block Ptmn is a pattern that is line-symmetrical in the relative movement direction of the printing position of the printed block Ptmn, and can be detected by pattern matching. In deriving each candidate correction value among the multiple candidates for correction values, difference information between the printing positions of two blocks Ptmn among the multiple blocks Ptmn is used. The two blocks Ptmn used to obtain the difference information are printed adjacent to each other in a direction intersecting the relative movement direction.

[0216] When the printing position where the patch Ptmn is printed is determined by pattern matching based on image data captured by a camera, it is preferable to eliminate the influence of aberration of the lens included in the camera.

[0217] According to the present embodiment, the two blocks Ptmn for detecting the difference information of the printing position are printed adjacent to each other in a direction intersecting the relative movement direction, and thus the influence of lens aberration can be reduced.

[0218] 2. Implementation Method 2

[0219] Next, refer to Figures 22 to 24 A description will be given of a printing device 1L as a liquid ejecting device according to Embodiment 2. In the description, the same components as those in the above-described embodiment are denoted by the same reference numerals, and duplicate descriptions are omitted.

[0220] In the first embodiment, the printing unit 100 included in the printing apparatus 1 is described as a serial printer, but it may also be a line printer.

[0221] The printing device 1L includes a printing unit 100L instead of the printing unit 100 in Embodiment 1. The printing unit 100L is an inkjet line printer that prints a desired image on the print medium 5 based on print data received from the image processing unit 110 .

[0222] The printing unit 100L is composed of an ink applying unit 10L, a moving unit 20L, a print control unit 30, and the like. The printing unit 100L receives print data from the image processing unit 110 and controls the ink applying unit 10L and the moving unit 20L based on the print data through the print control unit 30 to print an image on the print medium 5.

[0223] The ink applying section 10L is composed of a head unit 11L, an ink supply section 12 , a gap adjusting section 15L, and the like.

[0224] The moving section 20L is composed of a transport section 50 and the like. The transport section 50 is composed of a supply section 51, a storage section 52, transport rollers 53, a platen 55 and the like.

[0225] The head unit 11L includes a head 13L and a head control unit 14L. The head unit 11L is fixedly supported so that the lower surface of the head 13L faces the printing area where the platen 55 supports the print medium 5 .

[0226] like Figure 24 As shown, the nozzle 13L is viewed from the bottom surface. Figure 3The nozzle head 13 is shown rotated 90 degrees to the left. For simplicity of description, the nozzle head 13L is shown with the same configuration as the nozzle head 13 except for the orientation. However, it is preferable that the length of the nozzle unit 135, that is, the number of independent nozzle heads 134 included in the nozzle unit 135, is a number corresponding to the maximum width of the print medium 5 to be printed by the printing unit 100.

[0227] The gap adjustment unit 15L includes a support mechanism capable of changing the support position of the head unit 11L or the support position of the platen 55 in the Z-axis direction under the control of the print control unit 30 .

[0228] The printing control unit 30 prints a desired image on the printing medium 5 by repeatedly ejecting ink droplets from the nozzle 13L and moving the printing medium 5 along the Y-axis direction using the conveying roller 53 for the printing medium 5 supplied to the printing area by the supply unit 51 and the conveying roller 53.

[0229] In this embodiment, the relative movement direction is the conveying direction, that is, the Y-axis direction. Figures 4 to 8 The landing position deviation described above occurs in the Y-axis direction.

[0230] As the test pattern of this embodiment, the test pattern Tp in the embodiment 1 is replaced by Figure 25 The test pattern TpL shown in FIG. The test pattern TpL only needs to have a block Ptmn capable of detecting information related to the deviation of the landing position of the ink droplet in the Y-axis direction. Therefore, it does not necessarily need to have an image Gjk of the same shape as that of Embodiment 1. The image Gjk printed as the test pattern TpL only needs to be line-symmetrical in the relative movement direction of the nozzle head 13L and the print medium 5, that is, in the Y-axis direction.

[0231] That is, in the printing apparatus 1L, the moving unit 20 moves the head 13L and the print medium 5 relative to each other in the nozzle array direction. The plurality of patches Ptmn include patches Ptmn printed before and after the head 13L moves relative to the print medium 5 in the nozzle array direction.

[0232] In the liquid ejection device of this embodiment, since multiple candidates for correction values ​​for correcting the landing position deviation of ink droplets generated in the relative movement direction of the nozzle 13L and the printing medium 5 can be obtained, appropriate correction values ​​can be derived by statistically processing the multiple candidates for correction values ​​obtained.

[0233] In addition, in the above-mentioned embodiment, the case where there is one test pattern Tp and one test pattern TpL is described respectively, but it can also be configured as follows: printing multiple test patterns Tp and test patterns TpL respectively, and deriving appropriate correction values ​​based on the information related to the landing position deviation of multiple ink droplets obtained from the multiple test patterns Tp and test patterns TpL.

[0234] Furthermore, in the above-described embodiment, the printing unit 100 or the printing unit 100L is described as an inkjet printer that supplies long print media 5 wound in a roll. However, the print media is not limited to roll print media 5 and may also be sheet-like paper, for example. In the case of sheet-like paper, the supply unit 51 may be replaced with a supply mechanism including, for example, a separator for feeding the paper one by one, and the storage unit 52 may be replaced with, for example, a storage tray for storing the paper ejected after printing. With such a printing device, as long as a test pattern having multiple patches Ptmn, which can be used to obtain multiple candidate correction values ​​for correcting ink droplet landing position deviations, can be printed on multiple sheets of paper.

Claims

1. A liquid ejection device, characterized in that: have: a nozzle having a plurality of nozzles for ejecting liquid droplets toward a recording medium; a moving portion for moving the nozzle relative to the recording medium in a relative moving direction; as well as a control unit that controls the nozzle and the moving unit to record a test pattern on the recording medium, and calibrates the control of the nozzle and / or the moving unit based on a correction value obtained from the test pattern to perform recording; The test pattern has a plurality of blocks from which a plurality of candidates for the correction values ​​can be obtained, the correction values ​​being used to correct the landing position of the droplet on the recording medium in the relative moving direction. The plurality of blocks include a plurality of pattern images having shapes different from rectangles or grid lines, The plurality of pattern images respectively have gaps with pattern images adjacent to each other in the relative movement direction, and the plurality of pattern images are line-symmetrical images in the relative movement direction. Each of the plurality of pattern images has a shape different from the pattern image adjacent to the pattern image in the relative movement direction.

2. The liquid ejection device according to claim 1, wherein The nozzle head comprises a first nozzle row and a second nozzle row in which the nozzles are arranged along a nozzle row direction; The plurality of blocks include a plurality of blocks from which a plurality of offsets can be derived, the offsets being offsets in a relative movement direction between landing positions of droplets ejected from the nozzles of the first nozzle column and landing positions of droplets ejected from the nozzles of the second nozzle column.

3. The liquid ejection device according to claim 2, wherein: The plurality of blocks include a plurality of blocks capable of deriving a plurality of inference values; The multiple estimated values ​​include: a plurality of estimated values ​​of the ejection velocity of the liquid droplets ejected from the first nozzle of the first nozzle row; and A plurality of estimated values ​​of the discharge speed of the liquid droplets discharged from the second nozzle of the second nozzle row.

4. The liquid ejection device according to claim 3, wherein: The plurality of blocks include a plurality of blocks capable of deriving a plurality of inference values; The multiple estimated values ​​include: a plurality of estimated values ​​of the ejection velocity of the liquid droplets ejected from the third nozzle of the first nozzle array; and A plurality of estimated values ​​of the discharge speed of the liquid droplets discharged from the fourth nozzle of the second nozzle row.

5. The liquid ejection device according to claim 2, wherein: The plurality of blocks include a plurality of blocks capable of deriving a plurality of inference values; The multiple estimated values ​​include: a plurality of estimated values ​​of the distance from the first nozzle of the first nozzle array to the recording medium; and A plurality of estimated values ​​of the distance from the second nozzle of the second nozzle row to the recording medium.

6. The liquid ejection device according to claim 5, wherein: The plurality of blocks include a plurality of blocks capable of deriving a plurality of inference values; The multiple estimated values ​​include: a plurality of estimated values ​​of the distance from the third nozzle of the first nozzle array to the recording medium; and A plurality of estimated values ​​of the distance from the fourth nozzle of the second nozzle array to the recording medium.

7. The liquid ejection device according to claim 2, wherein: The nozzle head includes a first nozzle unit and a second nozzle unit, the first nozzle unit is composed of a plurality of nozzle columns in which the nozzles are arranged, and the second nozzle unit is different from the first nozzle unit and is composed of a plurality of nozzle columns in which the nozzles are arranged; The first nozzle array is included in the first nozzle unit, and the second nozzle array is included in the second nozzle unit.

8. The liquid ejection device according to any one of claims 2 to 7, wherein: The moving unit relatively moves the nozzle head and the recording medium in a first direction intersecting the nozzle array direction and in a second direction opposite to the first direction; The plurality of blocks include: a block for performing recording while the head moves in the first direction relative to the recording medium; and A block that performs recording while the head moves in the second direction relative to the recording medium.

9. The liquid ejection device according to any one of claims 2 to 7, wherein: The moving portion moves the nozzle head and the recording medium relative to each other in the direction of the nozzle array; The plurality of blocks include blocks recorded before and after the head moves relative to the recording medium in the nozzle array direction.

10. A method for adjusting a liquid ejection device, characterized in that: The liquid ejection device comprises: a nozzle having a plurality of nozzles for ejecting liquid droplets toward a recording medium; and a moving portion for moving the nozzle relative to the recording medium in a relative moving direction; The adjustment method of the liquid ejection device includes: a test pattern recording step of controlling the nozzle and the moving portion to record a test pattern on the recording medium, the test pattern having a plurality of blocks that are candidates for obtaining a plurality of correction values, the correction values ​​being used to correct a landing position of the droplet on the recording medium in the relative moving direction; a correction value candidate deriving step of deriving a plurality of correction value candidates from the test pattern; and a correction value determination step of performing statistical processing on the derived plurality of correction value candidates to determine the correction value; The plurality of blocks include a plurality of pattern images having shapes different from rectangles or grid lines, The plurality of pattern images respectively have gaps with pattern images adjacent to each other in the relative movement direction, and the plurality of pattern images are line-symmetrical images in the relative movement direction. Each of the plurality of pattern images has a shape different from the pattern image adjacent to the pattern image in the relative movement direction.

11. The method for adjusting a liquid ejecting device according to claim 10, wherein: The block is a pattern that is line-symmetrical in the relative movement direction, so that a recording position of the block can be detected by pattern matching; Derivation of each of the plurality of correction value candidates uses information on a difference in recording positions between two of the plurality of blocks; The two blocks for obtaining the difference information are recorded adjacent to each other in a direction intersecting the relative movement direction.

Images