Inkjet recording device, inkjet recording method, and program

Abstract

This invention provides an inkjet recording device, an inkjet recording method, and a program that enable efficient adjustment of the ink ejection timing, even when the nozzle has a significant deviation in ink ejection characteristics compared to other nozzles. [Solution] The inkjet recording device 1 includes a chart forming unit 411 that causes the inkjet head to form a test chart for identifying the landing position of ink ejected from each of the multiple nozzles 2421 of the inkjet head 242; an acquisition unit 412 that acquires the landing positions of the multiple nozzles 2421 from an image of the test chart captured by an imaging unit 26; a detection unit 413 that detects the amount of landing deviation of the multiple nozzles 2421 from the landing positions; and an adjustment unit 414 that adjusts the landing positions of the multiple nozzles 2421 based on the detection result of the detection unit 413. The adjustment unit 414 excludes nozzles 2421 whose amount of landing deviation in the transport direction is greater than a predetermined value from the adjustment target for reducing the amount of landing deviation.

Description

Technical Field

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

Background Art

[0002] Conventionally, an inkjet recording apparatus that ejects ink onto a recording surface of a recording medium conveyed in a conveyance direction to record an image is known. In an inkjet recording apparatus, ink is ejected from nozzles of an inkjet head at an appropriate timing based on image data.

[0003] In an inkjet recording apparatus, due to manufacturing errors, nozzle clogging, etc., there may be a deviation in ejection speed and ejection angle for each nozzle. When such a so-called ejection deviation occurs, the ink lands at a position different from the target, so the image quality of the formed image deteriorates. Therefore, for example, Patent Document 1 describes an inkjet printer that corrects ejection deviation by acquiring the landing position of ink ejected from each nozzle and adjusting the ejection timing of each nozzle based on the acquired landing position.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, a nozzle having a significant deviation in ejection speed and ejection angle compared to other nozzles has unstable ink ejection itself. Therefore, even if the ejection timing is adjusted as in Patent Document 1, it is not possible to stably eject ink at the adjusted ejection timing, and ejection deviation still occurs, which is inefficient.

[0006] This invention has been made in view of the above circumstances. Its purpose is to provide an inkjet recording device, an inkjet recording method, and a program that can efficiently adjust the ejection timing even when equipped with a nozzle that exhibits a significant deviation in ink ejection characteristics compared to other nozzles. [Means for solving the problem]

[0007] To solve the above problems, the invention described in claim 1 is an inkjet recording apparatus, An inkjet head is positioned along the transport direction of the recording medium and forms an image by ejecting ink onto the recording medium from multiple nozzles, An imaging unit for capturing an image formed on the recording medium, A chart forming unit that causes the inkjet head to form a test chart for identifying the landing position of the ink ejected from each of the plurality of nozzles, An acquisition unit that acquires the landing positions of the ink ejected from the plurality of nozzles from the image of the test chart captured by the imaging unit, A detection unit for detecting the amount of deviation in the impact of ink ejected from the plurality of nozzles from the aforementioned impact position, The system includes an adjustment unit that adjusts the landing position of the ink ejected from the plurality of nozzles based on the detection result of the detection unit, The adjustment unit excludes nozzles whose projectile misalignment in the transport direction is greater than a predetermined value from the adjustments required to reduce the projectile misalignment.

[0008] The invention described in claim 2 is an inkjet recording apparatus as described in claim 1, The system includes a setting unit for setting the amount of ink dispensed by each of the aforementioned multiple nozzles, The adjustment unit causes the setting unit to set nozzles whose impact deviation in the transport direction is greater than a predetermined value as non-discharging nozzles that do not discharge ink.

[0009] The invention described in claim 3 is an inkjet recording apparatus as described in claim 1, The system includes a setting unit for setting the amount of ink dispensed by each of the aforementioned multiple nozzles, The adjustment unit excludes nozzles where the amount of impact deviation in the transport direction is greater than a predetermined value from the adjustment of the ink impact position. Based on the detection result of the detection unit after the adjustment unit has made adjustments, the setting unit sets the plurality of nozzles whose point of impact deviation is greater than a predetermined value as non-discharging nozzles that do not dispense ink.

[0010] The invention described in claim 4 is an inkjet recording apparatus as described in claim 1, The system includes a setting unit for setting the amount of ink dispensed by each of the aforementioned multiple nozzles, The adjustment unit increases the amount of impact deviation by adjusting the ink impact position for nozzles where the amount of impact deviation in the transport direction is greater than a predetermined value. Based on the detection result of the detection unit after the adjustment unit has made adjustments, the setting unit sets the plurality of nozzles whose point of impact deviation is greater than a predetermined value as non-discharging nozzles that do not dispense ink.

[0011] The invention described in claim 5 is an inkjet recording apparatus according to any one of claims 2 to 4, The system includes a supplementary unit that compensates for the ink set to be dispensed from the non-dispensing nozzle by dispensing it from an adjacent nozzle.

[0012] The invention described in claim 6 is, An inkjet head is positioned along the transport direction of the recording medium and forms an image by ejecting ink onto the recording medium from multiple nozzles, An inkjet recording method using an inkjet recording apparatus comprising an imaging unit for capturing an image formed on the recording medium, A chart formation step involves causing the inkjet head to form a test chart for identifying the landing position of the ink ejected from each of the plurality of nozzles, An acquisition step of obtaining the landing positions of the ink ejected from the plurality of nozzles from the image of the test chart captured by the imaging unit, A detection step of detecting the landing deviation amount of the ink ejected from the plurality of nozzles from the landing position; An adjustment step of adjusting the landing position of the ink ejected from the plurality of nozzles based on the detection result in the detection step, and The adjustment step excludes from the adjustment target for reducing the landing deviation amount, the nozzles in which the landing deviation amount in the conveyance direction is greater than a predetermined value.

[0013] The invention according to claim 7 is a program, An inkjet head that is arranged along the conveyance direction of a recording medium and forms an image by ejecting ink from a plurality of nozzles onto the recording medium, An imaging unit that images the image formed on the recording medium, and causes a computer of an inkjet recording apparatus including A chart forming unit that causes the inkjet head to form a test chart for identifying the landing position of the ink ejected from each of the plurality of nozzles, An acquisition unit that acquires the landing position of the ink ejected from the plurality of nozzles from an image of the test chart imaged by the imaging unit, A detection unit that detects the landing deviation amount of the ink ejected from the plurality of nozzles from the landing position, Function as an adjustment unit that adjusts the landing position of the ink ejected from the plurality of nozzles based on the detection result of the detection unit, The adjustment unit excludes from the adjustment target for reducing the landing deviation amount, the nozzles in which the landing deviation amount in the conveyance direction is greater than a predetermined value.

Advantages of the Invention

[0014] According to the present invention, even if there is a nozzle with a significant deviation in ink ejection characteristics compared to other nozzles, the ejection timing can be efficiently adjusted.

Brief Description of the Drawings

[0015] [Figure 1]It is a diagram showing a schematic configuration of an inkjet recording apparatus. [Figure 2] It is a perspective view of a conveyance unit. [Figure 3] It is a schematic diagram showing the configuration of a head unit and an imaging unit. [Figure 4] It is a schematic diagram showing the configuration of a head unit and an imaging unit. [Figure 5] It is a block diagram showing the main functional configuration of an inkjet recording apparatus. [Figure 6] It is a diagram showing an example of a first test chart. [Figure 7] It is a diagram showing an example of a second test chart. [Figure 8] It is a flowchart of landing position control processing. [Figure 9] It is a flowchart of landing deviation correction processing. [Embodiments for Carrying Out the Invention]

[0016] Hereinafter, an inkjet recording apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples and the following detailed description. In the following description, components having the same functions and configurations are denoted by the same reference numerals, and the description thereof is omitted.

[0017] [Overall Configuration of Inkjet Recording Apparatus] FIG. 1 is a diagram showing a schematic configuration of an inkjet recording apparatus 1 according to an embodiment of the present invention. The inkjet recording apparatus 1 includes a paper feeding unit 10, an image recording unit 20, a paper discharging unit 30, and a control unit 40 (see FIG. 5). Under the control of the control unit 40, the inkjet recording apparatus 1 conveys a recording medium stored in the paper feeding unit 10 to the image recording unit 20, records an image (inkjet image) on the recording medium in the image recording unit 20, and conveys the recording medium on which the image is recorded to the paper discharging unit 30.

[0018] As recording media, various media capable of fixing ink deposited on the surface can be used, including paper such as plain paper and coated paper, as well as fabrics or sheet-like resins. Furthermore, the recording media is not limited to short media such as sheet paper, but may also be long media such as roll paper supplied by a roll-to-roll system.

[0019] (Paper feed section) The paper feeding unit 10 comprises a paper feeding tray 11 and a media supply unit 12. The paper feeding tray 11 stores the recording medium. The media supply unit 12 transports and supplies the recording medium to the image recording unit 20. The media supply unit 12 comprises a ring-shaped belt supported on its inside by two rollers. The media supply unit 12 transports the recording medium from the paper feeding tray 11 to the image recording unit 20 by rotating the rollers with the recording medium placed on the belt.

[0020] (Image recording unit) The image recording unit 20 includes a transport unit 21, a transfer unit 22, a heating unit 23, a head unit 24, a fixing unit 25, an imaging unit 26, and a delivery unit 27, among others.

[0021] {Conveyor section} The transport unit 21 transports the recording medium in the transport direction, which is the direction of the transport drum 211's circumferential movement, by having a cylindrical transport drum 211, which holds the recording medium placed on the transport surface, rotate around a rotation axis (cylindrical axis) that extends in the width direction.

[0022] <Conveyor Drum> Figure 2 shows a perspective view of the conveying unit 21. The conveying drum 211 includes a claw portion 2111 and an air intake portion 2112 that hold the recording medium on its conveying surface.

[0023] <Claw area> The claw portion 2111 has a plurality of claws arranged in the width direction at predetermined positions on the conveying surface of the conveying drum 211. The claw portion 2111 holds the recording medium by gripping the vicinity of one side between itself and the conveying surface of the conveying drum 211. As a result, the recording medium is placed with its tip positioned at a predetermined mounting position defined by the claw portion 2111.

[0024] <Intake section> The intake unit 2112 includes a plurality of intake holes provided on the conveying surface of the conveying drum 211, and a suction force generating unit (not shown, e.g., an air pump or fan) that generates a suction force to draw gas into the conveying drum 211 through the intake holes. That is, the intake unit 2112 uses the suction force generated by the intake from the intake holes to draw the recording medium towards the conveying surface of the conveying drum 211.

[0025] Furthermore, the transport unit 21 is equipped with a transport drum motor (not shown) that rotates the transport drum 211, and rotates by an angle proportional to the amount of rotation of the transport drum motor. Note that in Figure 2, a portion of the recording medium is shown curled up from the transport surface of the transport drum 211; this is for the purpose of illustrating the air intake hole. Therefore, when the recording medium is transported by the transport drum 211, the entire recording medium is held so as to lie along the transport surface of the transport drum 211.

[0026] {Transfer Unit} Returning to Figure 1, the transfer unit 22 transfers the recording medium transported by the media supply unit 12 of the paper feeding unit 10 to the transport unit 21. The transfer unit 22 is located between the media supply unit 12 and the transport unit 21 of the paper feeding unit 10. The transfer unit 22 holds one end of the recording medium transported from the media supply unit 12 with its swing arm 221, picks it up, and transfers it to the transport unit 21 via the transfer drum 222.

[0027] {Heating part} The heating unit 23 is located between the position of the transfer drum 222 and the position of the head unit 24, and heats the recording medium being transported by the transport unit 21 so that it reaches a temperature within a predetermined temperature range. The heating unit 23 has, for example, an infrared heater, and energizes the infrared heater based on a control signal supplied from the control unit 40 to generate heat.

[0028] {Head Unit} The head unit 24 records an image by ejecting ink onto the recording medium from nozzle openings provided on the ink ejection surface facing the transport surface of the transport drum 211 at an appropriate timing corresponding to the rotation of the transport drum 211 in which the recording medium is held. The head unit 24 is positioned such that its ink ejection surface and the transport surface of the transport drum 211 are separated by a predetermined distance. In the inkjet recording apparatus 1 of this embodiment, four head units 24, each corresponding to one of the four ink colors, yellow (Y), magenta (M), cyan (C), and black (K), are arranged at predetermined intervals from upstream in the transport direction in the order of Y, M, C, and K.

[0029] Each head unit 24 is equipped with four inkjet heads 242 (hereinafter also referred to as the first inkjet head 242a to the fourth inkjet head 242d) in which multiple recording elements are arranged in the width direction, as shown in Figure 3. Each recording element provided on the inkjet head 242 is equipped with a pressure chamber for storing ink, a piezoelectric element provided on the wall of the pressure chamber, and a nozzle 2421 (see Figure 4). When a drive signal is input to deform the piezoelectric element, the pressure chamber deforms due to the deformation of the piezoelectric element, changing the pressure inside the pressure chamber, and ink is ejected from the nozzle 2421 that communicates with the pressure chamber. The amount of ink ejected from the nozzle 2421 can be adjusted by changing the amplitude of the voltage of the drive signal.

[0030] In the head unit 24, the nozzles 2421 are formed over the width of the image formation area (a predetermined recording width) of the recording medium. The head unit 24 is used in a fixed position relative to the transport drum 211 when recording an image. In other words, the inkjet recording device 1 is an inkjet recording device that performs single-pass (one-pass) image recording using a line head. In the inkjet recording device 1 of this embodiment, the ink ejection timing is adjusted according to the rotation of the transport drum 211 so that the recording resolution in the transport direction and width direction (i.e., the arrangement density of recording elements in the head unit 24) is 1200 dpi.

[0031] The ink ejected from the nozzle of the recording element is one that changes phase to a gel-like or sol-like state depending on the temperature and hardens when irradiated with energy rays such as ultraviolet light. In this embodiment, an ink that is gel-like at room temperature and becomes sol-like when heated is used. The head unit 24 is equipped with an ink heating unit (not shown) that heats the ink stored inside it. The ink heating unit operates under the control of the control unit 40 and heats the ink to a temperature at which it becomes sol-like. The inkjet head 242 ejects the heated, sol-like ink. When this sol-like ink is ejected onto the recording medium, after the ink lands on the recording medium, it cools naturally and quickly turns into a gel-like state, solidifying on the recording medium.

[0032] {Fixing part} Returning to Figure 1, the fixing unit 25 has an energy ray irradiation unit arranged in the width direction of the transport unit 21. The fixing unit 25 irradiates the recording medium placed on the transport unit 21 with energy rays such as ultraviolet light from the energy ray irradiation unit to harden and fix the ink ejected onto the recording medium. The energy ray irradiation unit of the fixing unit 25 is positioned facing the transport surface in the transport direction from the position of the head unit 24 to the position of the transfer drum 271 of the delivery unit 27, which will be described later.

[0033] {Imaging Unit} The imaging unit 26 is positioned between the ink fixing position by the fixing unit 25 and the placement position of the transfer drum 271, so as to be able to read the surface of the recording medium on the transport surface. The image data captured by the imaging unit 26 is sent to the acquisition unit 412 (described later) of the control unit 40.

[0034] <Line Sensor> As shown in Figure 3, the imaging unit 26 includes a first line sensor 262a and a second line sensor 262b (hereinafter, either one of these will be referred to as line sensor 262) attached to a mounting member 263. The imaging unit 26 uses the first line sensor 262a and the second line sensor 262b to capture images of partially different imaging ranges and reads the images recorded on the recording medium and the reference member 2121.

[0035] Figure 4 is a magnified view showing the overlapping arrangement ranges in the width direction of the first line sensor 262a and the second line sensor 262b, and the corresponding portion of the multiple inkjet heads 242. As shown in Figure 4, the first line sensor 262a and the second line sensor 262b each have an image sensor group 2621G consisting of multiple image sensors 2621 arranged at equal intervals in the width direction. Note that in Figure 4, the number of image sensors 2621 and nozzles 2421 has been omitted and is depicted as fewer than the actual number due to space limitations in the drawing.

[0036] The range R1 in the first line sensor 262a, which is within a predetermined vicinity range from the first end in the width direction of the arrangement range of the image sensor group 2621G, overlaps with the range R1 in the second end in the width direction of the arrangement range of the image sensor group 2621G in the second line sensor 262b. As a result, the arrangement ranges in the width direction of the image sensor groups 2621G of the first line sensor 262a and the second line sensor 262b are continuous. Furthermore, the arrangement ranges in the width direction of the image sensor groups 2621G of the first line sensor 262a and the second line sensor 262b are provided such that they encompass the width direction recording width of the image by the head unit 24, i.e., the width direction arrangement range of the nozzle 2421.

[0037] <Image sensor> The image sensor 2621 receives incident light that has been reflected from the surface of the recording medium, which is emitted from a light source (not shown), and outputs a signal corresponding to the intensity of the incident light. The first line sensor 262a and the second line sensor 262b output a signal representing the one-dimensional image output from the multiple image sensors 2621 of the image sensor group 2621G.

[0038] More specifically, each image sensor 2621 has three sub-image sensors arranged in the transport direction, each outputting a signal corresponding to the intensity of the R (red), G (green), and B (blue) wavelength components of the incident light. Therefore, in the image sensor group 2621G, there are three rows of sub-image sensor arrays, each corresponding to R, G, and B, arranged in the width direction. The sub-image sensors corresponding to R, G, and B are, for example, CCD (Charge Coupled Device) sensors or CMOS (Complementary Metal Oxide Semiconductor) sensors equipped with photodiodes as photoelectric conversion elements. Furthermore, each sub-image sensor has a color filter arranged in its light-receiving section that transmits light of the R, G, or B wavelength component.

[0039] In the image sensor group 2621G, the arrangement pitch of the image sensors 2621 in the width direction does not need to be equal to the arrangement pitch of the nozzles 2421 in the width direction in the head unit 24. In this embodiment, the arrangement pitch of the image sensors 2621 is twice that of the arrangement pitch of the nozzles 2421, and the reading resolution in the width direction is 600 dpi. In addition, the output timing of the signal from the line sensor 262 is adjusted so that the reading resolution in the transport direction is 600 dpi.

[0040] The positional relationship between the inkjet head 242 of the head unit 24 and the first line sensor 262a and the second line sensor 262b will now be explained. As shown in Figure 3, the head unit 24 has the first inkjet head 242a to the fourth inkjet head 242d arranged sequentially in the width direction with respect to the mounting member 243. Also, as shown in Figure 4, each inkjet head 242 has two nozzle rows, each composed of multiple nozzles 2421 arranged at equal intervals in the width direction, and these are arranged such that the width direction positions of the nozzles 2421 in each nozzle row are offset from each other. Furthermore, the nozzles 2421 included in the two nozzle rows constitute a nozzle group 2421G.

[0041] The nozzle group 2421G may consist of one nozzle row or three or more nozzle rows. The number of inkjet heads 242 in the head unit 24 may be three or fewer, or five or more. Alternatively, instead of inkjet heads 242, a head module may be used in which two or more inkjet heads 242 are combined with a slight offset in the width direction so that the widthwise positions of the nozzles 2421 do not overlap.

[0042] The four inkjet heads 242 are arranged in a staggered pattern so that the arrangement range in the width direction of the nozzle group 2421G is seamlessly connected. Specifically, the inkjet heads 242 are positioned such that the nozzle group end vicinity range R2 within a predetermined proximity range from the first end in the width direction of the arrangement range of the nozzle group 2421G overlaps with the nozzle group end vicinity range R2 at the second end in the width direction of the other nozzle group 2421G. As a result, the arrangement range in the width direction of the nozzle group 2421G of the four inkjet heads 242 is continuous.

[0043] Furthermore, as shown in Figure 4, the widthwise range in which the nozzle group end vicinity range R2 of the second inkjet head 242b and the third inkjet head 242c overlap is included in the range R1 of the first line sensor 262a and the second line sensor 262b. Therefore, the first inkjet head 242a and the second inkjet head 242b are provided such that the widthwise arrangement range of the nozzle group 2421G is included in the widthwise arrangement range of the image sensor group 2621G of the first line sensor 262a. Similarly, the third inkjet head 242c and the fourth inkjet head 242d are provided such that the widthwise arrangement range of the nozzle group 2421G is included in the widthwise arrangement range of the image sensor group 2621G of the second line sensor 262b. Therefore, images recorded by the first inkjet head 242a and the second inkjet head 242b can be captured by the first line sensor 262a. Furthermore, images recorded by the third inkjet head 242c and the fourth inkjet head 242d can be captured by the second line sensor 262b.

[0044] {Delivery Department} Returning to Figure 1, the delivery unit 27 comprises a transfer drum 271 and a belt loop 272. The transfer drum 271 is cylindrical and transfers the recording medium from the transport unit 21 to the belt loop 272. The belt loop 272 is ring-shaped and supported on the inside by two rollers. The delivery unit 27 transports the recording medium, which has been transferred from the transport unit 21 to the belt loop 272 by the transfer drum 271, and sends it to the paper discharge unit 30.

[0045] (Paper output section) The paper output unit 30 has a paper output tray 31. The paper output tray 31 is plate-shaped, and the recording medium sent from the image recording unit 20 by the delivery unit 27 is placed on it.

[0046] Figure 5 is a block diagram showing the main functional configuration of the inkjet recording device 1. The inkjet recording device 1 includes a heating unit 23, a head unit 24, a fixing unit 25, an imaging unit 26, a control unit 40, a transport drive unit 51, an operation display unit 52, an input / output interface 53, and a bus 54, etc.

[0047] <Head Control Unit> The head unit 24 includes a head control unit 241. The head control unit 241 outputs various control signals and image data to a head drive unit (not shown) of the inkjet head 242 at timings corresponding to control signals input from the control unit 40. Based on these outputs, the head control unit 241 causes the head drive unit to supply a drive signal to deform the piezoelectric element to the recording element, thereby ejecting ink from the nozzle 2421 of the recording element.

[0048] <Imaging Control Unit> The imaging unit 26 includes an imaging control unit 261. Based on control signals input from the control unit 40, the imaging control unit 261 images the surface of the recording medium using each line sensor 262. The imaging control unit 261 also generates imaging data based on the signals output from the image sensor group 2621G of each line sensor 262 as a result of the imaging and outputs it to the control unit 40. Specifically, the imaging control unit 261 amplifies the signals output from the image sensor group 2621G of each line sensor 262, performs AD (analog-to-digital) conversion, and generates digital data that indicates the light detection intensity by the image sensor 2621 in, for example, 256 gradations. The imaging control unit 261 also corrects (white correction) the obtained digital data according to calibration data that has been generated in advance and stored in the storage unit 44. Here, the calibration data is a correction value that converts the value of the digital data obtained by imaging a predetermined standard white plate with each line sensor to a value corresponding to the reflectance of the standard white plate. The imaging control unit 261 outputs imaging data consisting of white-corrected digital data to the control unit 40, causing the storage unit 44 to store the imaging data.

[0049] (Control Unit) The control unit 40 includes a CPU (Central Processing Unit) 41, RAM (Random Access Memory) 42, ROM (Read Only Memory) 43, and a storage unit 44.

[0050] {CPU} The CPU 41 reads various control programs and setting data stored in the ROM 43, stores them in the RAM 42, and executes the programs to perform various calculations. The CPU 41 also provides overall control over the operation of the inkjet recording device 1.

[0051] {RAM} RAM42 provides the CPU41 with a working memory space and stores temporary data. RAM42 may also include non-volatile memory.

[0052] {ROM} ROM43 stores various control programs and setting data executed by the CPU41. Alternatively, rewritable non-volatile memory such as EEPROM (Electrically Erasable Programmable Read Only Memory) or flash memory may be used instead of ROM43.

[0053] {Storage section} The storage unit 44 stores print jobs (image recording commands) and image data related to those print jobs input from the external device 2 via the input / output interface 53, image data of the test chart described later, and imaging data generated by the imaging unit 26. The storage unit 44 also stores image sensor misalignment information indicating the misalignment of the image sensor 2621, corrected impact position information relating to the impact position of the ink, and impact position misalignment information indicating the amount of misalignment of the ink impact position. Image sensor misalignment information, corrected impact position information, and impact position misalignment information will be described later. For example, an HDD (Hard Disk Drive) can be used as the storage unit 44, and DRAM (Dynamic Random Access Memory) may also be used in combination.

[0054] The control unit 40 functions as a chart formation unit 411, acquisition unit 412, detection unit 413, adjustment unit 414, setting unit 415, and complementation unit 416 when the CPU 41 executes a program stored in the ROM 43.

[0055] <Chart Formation Section> The chart formation unit 411 controls the head control unit 241 to form a predetermined test chart stored in the storage unit 44 on the recording medium at a preset timing. The chart formation unit 411 controls the head control unit 241 to form a first test chart 60 and a second test chart 70.

[0056] The first test chart 60 is composed of positional misalignment detection marks and dots formed by each nozzle 2421, as shown in Figure 6, for example. The first test chart 60 is formed to identify the landing position of the ink ejected from the nozzle 2421 in the transport direction. If there is an ejection misalignment in the transport direction of the nozzle 2421, a dot will be formed at a location that is shifted in the transport direction relative to other dots, as shown by the dashed line in Figure 6.

[0057] The first test chart 60 is thus composed mainly of multiple high-resolution dots. Therefore, the chart forming unit 411 forms the first test chart 60 during setup of the inkjet recording device 1, for example, when replacing the inkjet head 242.

[0058] The second test chart 70 is a ladder-shaped chart composed of line segments formed by each nozzle 2421, which are shifted in position in the transport direction by units of several nozzles, as shown in Figure 7, for example. The second test chart 70 is formed to identify the landing position of the ink ejected from the nozzle 2421 in the width direction and to detect ejection defects. If there is an ejection misalignment in the width direction of the nozzle 2421, a misalignment occurs in the position of adjacent line segments, and the uniform pattern is disrupted.

[0059] On the other hand, as described above, in the second test chart 70, each nozzle 2421 forms a line segment extending in the transport direction. Therefore, if there is a misalignment in the ejection direction of a nozzle 2421, the line segment in the transport direction corresponding to that nozzle 2421 will be interrupted midway, as shown by the dashed-dotted line in Figure 7. Similarly, if a nozzle 2421 becomes a defective nozzle that can no longer eject ink, the line segment in the transport direction corresponding to that nozzle 2421 will not be formed.

[0060] Unlike the first test chart 60, the second test chart 70 does not require high-resolution image formation at the dot level. Therefore, it may be formed, for example, in a non-image-forming area of ​​the recording medium. Alternatively, it may be formed, for example, at a predetermined timing after the image formation process has been performed.

[0061] <Acquisition part> Returning to Figure 5, the acquisition unit 412 acquires the landing positions of the ink ejected by each nozzle 2421 based on the image data obtained by the imaging unit 26 capturing the test chart.

[0062] <Detection Unit> The detection unit 413 detects misalignment by comparing the landing positions of the ink ejected by each nozzle 2421, acquired by the acquisition unit 412, with the original data of the test chart stored in the storage unit 44. Furthermore, if the detection unit 413 detects that a predetermined nozzle 2421 has misalignment, it acquires the amount of misalignment.

[0063] <Adjustment section> The adjustment unit 414 adjusts the landing position of the ink ejected from each nozzle 2421 by adjusting the ejection timing of each nozzle 2421 based on the amount of offset of the ink ejected by each nozzle 2421, which is acquired by the detection unit 413.

[0064] <Settings section> The setting unit 415 sets the amount of ink ejected by each nozzle 2421. In the impact position control process described later, the setting unit 415 sets nozzles 2421 whose impact deviation in the transport direction is greater than a predetermined value as non-ejecting nozzles with an ejection amount of 0 (i.e., no ink is ejected). The predetermined value refers to, for example, 10 times the recording resolution.

[0065] <Supplementary section> The supplementation unit 416 compensates when a predetermined nozzle 2421 becomes a non-discharge nozzle by setting it to dispense the ink that is set to discharge from that nozzle 2421 to, for example, an adjacent nozzle located next to that nozzle 2421 in the transport direction or width direction. The supplementation unit 416 then stores this setting as a missing supplementation setting in the storage unit 44.

[0066] {Transport drive unit} The transport drive unit 51 supplies a drive signal to the transport drum motor of the transport drum 211 based on a control signal supplied from the control unit 40, causing the transport drum 211 to rotate at a predetermined speed and timing. The transport drive unit 51 also supplies drive signals to motors that operate the medium supply unit 12, the transfer unit 22, and the delivery unit 27 based on a control signal supplied from the control unit 40, causing the recording medium to be supplied to the transport unit 21 and discharged from the transport unit 21.

[0067] {Operation display section} The operation display unit 52 includes a display device and an input device. The display device is, for example, a liquid crystal display or an organic EL display. The input device is, for example, an operation key or a touch panel superimposed on the screen of the display device. The operation display unit 52 displays various information on the display device and converts user input operations to the input device into operation signals and outputs them to the control unit 40.

[0068] {Input / Output Interface} The input / output interface 53 mediates the transmission and reception of data between the external device 2 and the control unit 40. The input / output interface 53 is composed of, for example, various serial interfaces, various parallel interfaces, or a combination thereof.

[0069] {bus} Bus 54 is a path for sending and receiving signals between the control unit 40 and other components.

[0070] (external device) External device 2 is, for example, a personal computer, which supplies print jobs and image data, etc., to the control unit 40 via the input / output interface 53.

[0071] [Impact position control processing] The impact position control process using this inkjet recording device 1 will be explained based on the flowcharts in Figures 8 and 9.

[0072] First, the control unit 40 performs an ink misalignment correction process when setting up the inkjet recording device 1 (step S101). In the ink misalignment correction process, the chart formation unit 411 forms a first test chart 60 on the recording medium in order to detect the ink misalignment in the transport direction (step S1011). The acquisition unit 412 acquires image data of the first test chart 60 captured by the imaging unit 26 and obtains the landing position of the ink ejected by each nozzle 2421 (step S1012). Then, the detection unit 413 acquires the amount of ink misalignment in the transport direction of the ink ejected by each nozzle 2421 (step S1013). The adjustment unit 414 corrects the ink misalignment in the transport direction by correcting the ejection timing only for the nozzles 2421 whose amount of ink misalignment in the transport direction is less than or equal to a predetermined value (step S1014). On the other hand, the adjustment unit 414 does not correct the discharge timing or adjust the impact deviation for nozzles 2421 whose impact deviation in the transport direction is greater than a predetermined value.

[0073] After the impact misalignment correction process is executed, the control unit 40 waits until a predetermined timing for forming the second test chart 70 (step S102). When the predetermined timing is reached (step S102; Yes), the chart formation unit 411 causes the head unit 24 to form the second test chart 70 on the recording medium for detecting impact misalignment in the width direction and missing nozzles (step S103). Once the second test chart 70 is formed on the recording medium, the acquisition unit 412 acquires image data of the second test chart 70 captured by the imaging unit 26 and obtains the impact position of the ink ejected by each nozzle 2421 (step S104). The detection unit 413 then obtains the amount of impact misalignment in the width direction for each nozzle 2421 (step S105). At this time, the detection unit 413 also determines whether or not there are nozzles 2421 whose impact misalignment in the transport direction is greater than a predetermined value (step S106).

[0074] If there is a nozzle 2421 whose projectile misalignment in the transport direction is greater than a predetermined value (step S106; Yes), the setting unit 415 sets that nozzle 2421 as a non-discharge nozzle (step S107). The setting unit 415 also sets any other nozzles 2421 whose projectile misalignment in the width direction is greater than or equal to a predetermined value as non-discharge nozzles (step S108).

[0075] On the other hand, if there is no nozzle 2421 whose impact deviation in the transport direction is greater than a predetermined value (step S106; No), the setting unit 415 proceeds to step S108 and terminates the impact position control process. Then, during the subsequent image forming process, the compensation unit 416 compensates for the ink that a non-discharge nozzle has been set to discharge by an adjacent nozzle adjacent to that non-discharge nozzle.

[0076] [Effects of the Embodiment] As described above, the inkjet recording apparatus 1 according to this embodiment includes an inkjet head 242, an imaging unit 26, a chart forming unit 411, an acquisition unit 412, a detection unit 413, an adjustment unit 414, and a setting unit 415. The adjustment unit 414 excludes a plurality of nozzles 2421 in the first test chart 60 whose ink placement deviation in the transport direction is greater than a predetermined value from the adjustment target for the ink placement position, and does not make them subject to adjustment to reduce the amount of placement deviation. This configuration is efficient because it excludes nozzles 2421 whose ink ejection characteristics deviate significantly compared to other nozzles 2421 and which cannot be ejected stably even after adjustment from the adjustment target.

[0077] Then, after the adjustment by the adjustment unit 414, the setting unit 415, based on the detection result of the detection unit 413, designates any nozzle 2421 whose amount of impact deviation in the transport direction is greater than a predetermined value as a non-discharge nozzle. With this configuration, any nozzle 2421 whose amount of impact deviation is greater than a predetermined value and which cannot stably discharge ink to the adjusted impact position even after adjusting the impact position of the discharged ink is designated as a non-discharge nozzle. Therefore, even if a nozzle 2421 has a significantly greater deviation in ink discharge characteristics compared to other nozzles 2421, a decrease in image quality can be suppressed.

[0078] Furthermore, the inkjet recording apparatus 1 according to this embodiment includes a complementation unit 416 that compensates for ink set to be ejected from a non-ejecting nozzle by ejecting it from an adjacent nozzle. With this configuration, it is possible to suppress the deterioration of image quality caused by the non-ejecting setting of nozzle 2421.

[0079] [Other configurations] Although several embodiments of the present invention have been described, the scope of the present invention is not limited to the embodiments described above, but includes the scope of the invention as described in the claims and its equivalents.

[0080] For example, in the above example, in the impact position control process, if there is a nozzle 2421 whose impact deviation in the transport direction is greater than a predetermined value, the setting unit 415 sets the corresponding nozzle 2421 as a non-discharge nozzle. However, if the adjustment unit 414 and the setting unit 415 have a cooperative function, the adjustment unit 414 may, at step S1014, cause the setting unit 415 to set a nozzle 2421 whose impact deviation in the transport direction is greater than a predetermined value as a non-discharge nozzle.

[0081] Furthermore, in the above example, the adjustment unit 414 does not adjust the landing position of the ink ejected from nozzle 2421 in the first test chart 60 if the amount of landing deviation in the transport direction is greater than a predetermined value, but the system is not limited to this. In step S1014, the adjustment unit 414 may adjust the landing position of the ink ejected from nozzle 2421 so that the amount of landing deviation in the transport direction becomes larger. With this configuration, the ejection position of nozzle 2421 is shifted significantly when the second test chart 70 is formed. Therefore, in step S108, nozzle 2421 can be set as a non-ejecting nozzle.

[0082] Furthermore, there is a limit to how much the complementary unit 416 can substitute for the discharge amount of a non-discharge nozzle with an adjacent nozzle. Therefore, if the complementary unit 416 determines that the discharge amount of a non-discharge nozzle can no longer be adequately replaced by the adjacent nozzle, the operation display unit 52 may notify the user to replace the corresponding inkjet head 242. Also, although the above assumes that an adjacent nozzle is a nozzle arranged adjacent to a non-discharge nozzle in the transport direction or width direction, it is not limited to this. Moreover, the discharge amount of a non-discharge nozzle does not need to be compensated for by a single adjacent nozzle; it can be compensated for by multiple adjacent nozzles.

[0083] Furthermore, while the above discloses examples in which hard disks, semiconductor non-volatile memory, etc., are used as ROMs as computer-readable media for the program according to the present invention, the invention is not limited to these examples. Portable recording media such as CD-ROMs can be used as other computer-readable media. In addition, carrier waves can be used as a medium for providing the data of the program according to the present invention via a communication line. [Explanation of Symbols]

[0084] 1. Inkjet recording device 242 Inkjet Heads 2421 Nozzle 26 Imaging Department 411 Chart Formation Section 412 Acquisition Department 413 Detection Unit 414 Adjustment section 415 Settings Section 60 First Test Chart 70 Second Test Chart

Claims

1. An inkjet head is positioned along the transport direction of the recording medium and forms an image by ejecting ink onto the recording medium from multiple nozzles, An imaging unit for capturing an image formed on the recording medium, A chart forming unit that causes the inkjet head to form a test chart for identifying the landing position of the ink ejected from each of the plurality of nozzles, An acquisition unit that acquires the landing positions of the ink ejected from the plurality of nozzles from the image of the test chart captured by the imaging unit, A detection unit for detecting the amount of deviation in the impact of ink ejected from the plurality of nozzles from the aforementioned impact position, The system includes an adjustment unit that adjusts the landing position of the ink ejected from the plurality of nozzles based on the detection result of the detection unit, The adjustment unit excludes nozzles whose projectile misalignment in the transport direction is greater than a predetermined value from the adjustment target for reducing the projectile misalignment.

2. The system includes a setting unit for setting the amount of ink dispensed by each of the aforementioned multiple nozzles, The inkjet recording apparatus according to claim 1, wherein the adjustment unit causes the setting unit to set nozzles whose impact deviation in the transport direction is greater than a predetermined value as non-discharging nozzles that do not discharge ink.

3. The system includes a setting unit for setting the amount of ink dispensed by each of the aforementioned multiple nozzles, The adjustment unit excludes nozzles where the amount of impact deviation in the transport direction is greater than a predetermined value from the adjustment of the ink impact position. The inkjet recording apparatus according to claim 1, wherein the setting unit sets the plurality of nozzles whose impact deviation is greater than a predetermined value as non-ejecting nozzles that do not eject ink, based on the detection result of the detection unit after adjustment by the adjustment unit.

4. The system includes a setting unit for setting the amount of ink dispensed by each of the aforementioned multiple nozzles, The adjustment unit increases the amount of impact deviation by adjusting the ink impact position for nozzles where the amount of impact deviation in the transport direction is greater than a predetermined value. The inkjet recording apparatus according to claim 1, wherein the setting unit sets the plurality of nozzles whose impact deviation is greater than a predetermined value as non-ejecting nozzles that do not eject ink, based on the detection result of the detection unit after adjustment by the adjustment unit.

5. The inkjet recording apparatus according to any one of claims 2 to 4, further comprising a supplementary unit that supplements the ink set to be ejected from the non-ejecting nozzle by ejecting it from an adjacent nozzle.

6. An inkjet head is positioned along the transport direction of the recording medium and forms an image by ejecting ink onto the recording medium from multiple nozzles, An inkjet recording method using an inkjet recording apparatus comprising an imaging unit for capturing an image formed on the recording medium, A chart formation step involves causing the inkjet head to form a test chart for identifying the landing position of the ink ejected from each of the plurality of nozzles, An acquisition step of obtaining the landing positions of the ink ejected from the plurality of nozzles from the image of the test chart captured by the imaging unit, A detection step for detecting the amount of deviation in the landing position of the ink ejected from the plurality of nozzles from the aforementioned impact position, The system includes an adjustment step that adjusts the landing position of the ink ejected from the plurality of nozzles based on the detection results in the detection step, The adjustment step is an inkjet recording method in which nozzles whose impact deviation in the transport direction is greater than a predetermined value are excluded from the adjustment to reduce the impact deviation.

7. An inkjet head is positioned along the transport direction of the recording medium and forms an image by ejecting ink onto the recording medium from multiple nozzles, A computer for an inkjet recording apparatus, comprising an imaging unit for capturing an image formed on the recording medium, A chart forming unit that forms a test chart on the inkjet head for identifying the landing position of the ink ejected from each of the plurality of nozzles, An acquisition unit acquires the landing positions of the ink ejected from the plurality of nozzles from the image of the test chart captured by the imaging unit. A detection unit that detects the amount of deviation in the landing position of the ink ejected from the plurality of nozzles from the aforementioned impact position. Based on the detection results of the detection unit, it functions as an adjustment unit that adjusts the landing position of the ink ejected from the plurality of nozzles. The adjustment unit includes a program that excludes nozzles whose projectile misalignment in the transport direction is greater than a predetermined value from the adjustments required to reduce the projectile misalignment.

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