JP6239898B2 - Recording apparatus, recording method, and recording medium - Google Patents

Description

  The present invention relates to a recording apparatus and a recording method for recording an image or the like by discharging droplets onto a recording medium. Furthermore, the present invention relates to a recording medium having a test pattern recorded by the recording apparatus.

  2. Description of the Related Art Conventionally, a recording apparatus that records an image on a printing paper by ejecting ink from a plurality of nozzles provided in the ink head while relatively moving the printing paper and the ink head is known. As an ink head of this type of recording apparatus, an ink head in which a plurality of nozzles arranged in a straight line perpendicular to the relative movement direction is arranged in a plurality of rows in the relative movement direction is used (for example, Patent Documents). 1).

  In the recording apparatus described in Patent Document 1, each ink head has a plurality of nozzle rows each having nozzles arranged at predetermined distances. In a plurality of nozzle arrays that overlap in the relative movement direction, the nozzles included in each nozzle array are arranged at positions that do not overlap with the nozzles included in other nozzle arrays in the relative movement direction (different positions with respect to the direction perpendicular to the relative movement direction). (Paragraphs 0037 to 0039). If such an ink head is used, the printing pitch can be reduced and the printing performance can be improved. However, it is necessary to adjust the ejection timing of ink from each nozzle row and align the ink ejection positions on the printing paper.

JP 2009-279811 A Japanese Patent Laid-Open No. 10-329381 JP 2010-214630 A

  As a technique for adjusting the ejection position of ink from the ink head, conventionally, a method of printing a plurality of test patterns with ejection timings shifted by a predetermined amount and comparing the test patterns is used (for example, Patent Document 2). ).

  However, in the method described in Patent Document 2, in order to include a test pattern having an optimum timing among a plurality of test patterns, it is necessary to print many test patterns by changing the ejection timing in small increments. For this reason, a large amount of ink is required for printing the test pattern.

  On the other hand, as a technique for adjusting the ink ejection position between nozzle arrays, conventionally, a different color ink is ejected from each of the two nozzle arrays, and a pattern is printed that targets the same position on the printing paper. A method of recognizing the displacement direction of discharge between nozzle rows from blurring is used (for example, Patent Document 3).

  However, in the method described in Patent Document 3, it is necessary that the two nozzle arrays that adjust the ejection timing eject ink of different colors (paragraph 0022, FIG. 3). For this reason, it is not possible to adjust the ejection timing between the nozzle rows for a plurality of nozzle rows that eject the same color of ink as in the recording apparatus described in Patent Document 1.

  Further, in the method described in Patent Document 3, it is necessary to print a pattern targeting the same position on the printing paper from each nozzle so that the symbols printed by each nozzle row overlap (claim 1, paragraph) 0008). However, when the ink head has a plurality of nozzle arrays that eject ink of the same color as in the recording apparatus described in Patent Document 1, the nozzles included in each nozzle array are the nozzles included in the other nozzle arrays. These are arranged at positions that do not overlap with the relative movement direction (different positions with respect to the direction perpendicular to the relative movement direction). In such a recording apparatus, the nozzles included in each nozzle row cannot be printed such that the nozzles included in the other nozzle rows completely overlap with the design.

  The present invention has been made in view of such circumstances, and for a recording apparatus having a nozzle head having a plurality of nozzle rows in which a plurality of nozzles are linearly arranged, nozzles are printed by printing a small number of test patterns. It is an object of the present invention to provide a technique capable of correcting a recording position shift between columns.

In order to solve the above problems, a first invention of the present application is a recording apparatus that records characters or images on a recording medium by discharging the liquid droplets onto the recording medium, and discharges the liquid droplets. A nozzle head having a plurality of nozzles; a relative movement means for relatively moving the recording medium and the nozzle head in a first direction; and a discharge controller for controlling the discharge of droplets from the nozzles. The nozzle head has a structure in which a plurality of nozzle rows each including a plurality of the nozzles arranged linearly in a second direction orthogonal to the first direction are arranged in the first direction, The control unit distinguishes a band-like region extending in the second direction at a predetermined position in the first direction on the recording medium into a reference region and an adjustment region, and one reference nozzle included in the plurality of nozzle rows from the column, the reference territory Whole and, by ejecting droplets as target and at least a portion of said adjustment region, a reference pattern is recorded, from the adjustment target nozzle array included in a plurality of the nozzle rows other than the reference nozzle row, the adjusting The adjustment target pattern is recorded by ejecting droplets targeting the area.

A second invention of the present application is the recording apparatus according to the first invention, wherein the ejection control unit ejects liquid droplets from the reference nozzle row, targeting the entire reference area and a part of the adjustment area. Thus, the reference pattern is recorded, and the adjustment target pattern is recorded by ejecting droplets from the adjustment target nozzle row targeting another part of the adjustment region.

A third invention of the present application is the recording apparatus according to the first invention, wherein the ejection control unit ejects liquid droplets from the reference nozzle row to target the entire reference area and the entire adjustment area. A reference pattern is recorded, and an adjustment target pattern is recorded by ejecting droplets from the adjustment target nozzle row to target the entire adjustment region.

According to a fourth aspect of the present invention, there is provided a recording apparatus for recording characters and images on the recording medium by discharging the liquid droplets onto the recording medium, wherein the nozzle head has a plurality of nozzles for discharging the liquid droplets. And a relative movement means for relatively moving the recording medium and the nozzle head in a first direction, and a discharge controller for controlling the discharge of liquid droplets at the nozzle, the nozzle head comprising: A plurality of nozzle rows arranged in a straight line in a second direction orthogonal to the first direction, wherein a plurality of nozzle arrays are arranged in the first direction; One reference nozzle row included in the plurality of nozzle rows by distinguishing a band-like region extending in the second direction at a predetermined position in the first direction on the medium into a plurality of reference regions and a plurality of adjustment regions From at least the above criteria By ejecting liquid droplets with an area as a target, a reference pattern is recorded, and liquid droplets are ejected with an adjustment area as a target from an adjustment target nozzle array included in the plurality of nozzle arrays other than the reference nozzle array The adjustment target pattern is recorded, and the plurality of adjustment regions include a plurality of first adjustment regions, and the first adjustment region is the adjustment region and is one of the adjustment target nozzle rows. A target area for ejecting droplets from the target nozzle row, the plurality of reference areas and the plurality of first adjustment areas are alternately arranged in the second direction.

A fifth invention of the present application is the recording medium having a test pattern recorded using a recording apparatus that records characters and images on the recording medium by discharging droplets onto the recording medium. The recording apparatus includes a nozzle head having a plurality of nozzles for discharging droplets, and a relative movement unit that relatively moves the recording medium and the nozzle head in a first direction. Has a structure in which a plurality of nozzle arrays each including a plurality of nozzles arranged in a straight line at equal intervals in a second direction orthogonal to the first direction are arranged in the first direction, and the test pattern is The test pattern is arranged in a band-like region extending in the second direction at a predetermined position in the first direction on the recording medium, and the test pattern is arranged in the second direction with a plurality of reference dots arranged in the second direction. ,plural The distance between the center point of one of the reference dots and the center point of the other reference dot is an integer multiple of a predetermined distance, and the center of the one adjustment target dot The distance between the point and the center point of the other adjustment target dots is a distance that is an integral multiple of the predetermined distance, and the distance between the center point of one reference dot and the center point of one adjustment target dot is Unlike the distance that is an integral multiple of the predetermined distance, the band-shaped region includes only a plurality of the reference dots, a reference region, a plurality of the reference dots, and a plurality of the adjustment target dots. And an adjustment area.

6th invention of this application is a recording medium of 5th invention, Comprising: The said some reference | standard dot is arrange | positioned in the said whole reference | standard area | region and a part of said adjustment area | regions, and the said several adjustment object dot is said adjustment Located in another part of the region.

7th invention of this application is a recording medium of 5th invention, Comprising: The said some reference | standard dot is arrange | positioned in the said whole reference | standard area | region and the whole said adjustment | control area | region, and the said several adjustment object dot is the said whole adjustment | control area Placed in.

An eighth invention of the present application is the recording medium having a test pattern recorded by using a recording apparatus that records characters and images on the recording medium by discharging droplets onto the recording medium. The recording apparatus includes a nozzle head having a plurality of nozzles for discharging droplets, and a relative movement unit that relatively moves the recording medium and the nozzle head in a first direction. Has a structure in which a plurality of nozzle arrays each including a plurality of nozzles arranged in a straight line at equal intervals in a second direction orthogonal to the first direction are arranged in the first direction, and the test pattern is The test pattern is arranged in a band-like region extending in the second direction at a predetermined position in the first direction on the recording medium, and the test pattern is arranged in the second direction with a plurality of reference dots arranged in the second direction. ,plural The distance between the center point of one of the reference dots and the center point of the other reference dot is an integer multiple of a predetermined distance, and the center of the one adjustment target dot The distance between the point and the center point of the other adjustment target dots is a distance that is an integral multiple of the predetermined distance, and the distance between the center point of one reference dot and the center point of one adjustment target dot is Unlike the distance that is an integral multiple of the predetermined distance, the band-shaped area includes a plurality of reference areas in which only the plurality of reference dots are arranged, and a plurality of adjustment areas in which the plurality of adjustment target dots are arranged. The plurality of reference regions and the plurality of adjustment regions are alternately arranged in the second direction.

According to a ninth aspect of the present invention, there is provided a recording method using a recording apparatus that records characters and images on the recording medium by discharging the liquid droplets onto the recording medium. A nozzle head having a plurality of nozzles for discharging ink, and relative movement means for relatively moving the recording medium and the nozzle head in a first direction, wherein the nozzle head is orthogonal to the first direction. A plurality of nozzle arrays arranged in a straight line in the second direction have a structure in which a plurality of nozzle arrays are arranged in the first direction; a) a predetermined position in the first direction on the recording medium In which a band-like region extending in the second direction is distinguished into a reference region and an adjustment region;
b) After step a), a reference pattern is ejected from one reference nozzle array included in the plurality of nozzle arrays, targeting the reference area and at least a part of the adjustment area. Recording a reference pattern, and
c) After the step a), the adjustment target pattern is recorded by ejecting droplets from the adjustment target nozzle rows included in the plurality of nozzle rows other than the reference nozzle row, targeting the adjustment region. An adjustment target pattern recording process;
d) a relative movement step of relatively moving the recording medium and the nozzle head in a first direction between the step b) and the step c);
Including a recording method.

A tenth invention of the present application is the recording method according to the ninth invention, wherein in the step b), droplets are ejected from the reference nozzle row targeting the entire reference region and a part of the adjustment region. ,
In the step c), droplets are ejected from the adjustment target nozzle row targeting another part of the adjustment region.

An eleventh invention of the present application is the recording method according to the ninth invention, wherein in the step b), droplets are ejected from the reference nozzle row targeting the entire reference region and the entire adjustment region, and the step c). ), Droplets are ejected from the adjustment target nozzle row targeting the entire adjustment region.

A twelfth invention of the present application is a recording method using a recording apparatus that records characters and images on the recording medium by ejecting the liquid droplets onto the recording medium. A nozzle head having a plurality of nozzles for discharging ink, and relative movement means for relatively moving the recording medium and the nozzle head in a first direction, wherein the nozzle head is orthogonal to the first direction. A plurality of nozzle arrays arranged in a straight line in the second direction have a structure in which a plurality of nozzle arrays are arranged in the first direction; a) a predetermined position in the first direction on the recording medium A preparation step for distinguishing the band-like region extending in the second direction into a reference region and an adjustment region in step b) After the step a), at least the reference nozzle row included in the plurality of nozzle rows Targeting the reference area A reference pattern recording step of recording a reference pattern by discharging droplets; and c) after the step a), from the adjustment target nozzle row included in the plurality of nozzle rows other than the reference nozzle row, The adjustment target pattern recording step of recording the adjustment target pattern by ejecting droplets targeting the adjustment region, and d) between the step b) and the step c), the recording medium and the nozzle head And in the step a), the band-like region is distinguished into a plurality of reference regions and a plurality of adjustment regions, and a plurality of the reference regions, The adjustment areas are alternately arranged in the second direction.

According to the first invention, the fifth invention, and the ninth invention of the present application, it is possible to obtain a reference pattern and an adjustment target pattern recorded with a predetermined position in the first direction on the recording medium as a target. By comparing these reference patterns with the adjustment target pattern, it is possible to correct the shift in the recording position between the nozzle rows. Only the reference pattern is recorded in the reference area, and the reference pattern and the adjustment target pattern are mixed in the adjustment area. For this reason, it is easy to visually confirm the shift amount of the recording positions of both patterns.

According to the second invention, the sixth invention, and the tenth invention of the present application, the reference pattern and the adjustment target pattern are mixed with little overlap in the adjustment region. As a result, the liquid droplets ejected from the reference nozzle row and the liquid droplets ejected from the adjustment target nozzle row hardly overlap each other. Therefore, blurring of droplets is suppressed, and more accurate concentration distribution data can be obtained. Further, the expansion and contraction of the recording medium caused by the overlapping of the droplets hardly occurs.

According to the third invention, the seventh invention, and the eleventh invention of the present application, the reference pattern and the adjustment target pattern overlap each other in the adjustment region, so that it is easy to visually confirm the shift amount of the recording positions of both patterns.

According to the fourth, eighth, and twelfth aspects of the present application, it is possible to improve the detection accuracy of the positional deviation amount by alternately arranging the reference region and the adjustment region corresponding to the adjustment target nozzle row. .

FIG. 2 is a diagram conceptually illustrating a configuration of a recording apparatus. It is a bottom view of a head unit. It is a bottom view of a nozzle head. 3 is a block diagram illustrating a control system of the recording apparatus. FIG. 2 is a flowchart showing a flow of printing in the recording apparatus of FIG. 1. It is the figure which showed the example of the linear pattern recorded using the recording device of FIG. 2 is a flowchart showing a test pattern printing flow in the recording apparatus of FIG. 1. It is a top view of the printing paper before and after printing a test pattern. It is the figure which showed the example of the partial top view and density distribution data of the test pattern which concern on one Embodiment. It is the figure which showed the example of the partial top view and density distribution data of the test pattern which concerns on other embodiment. It is the figure which showed the example of the partial top view and density distribution data of the test pattern which concerns on other embodiment. It is the figure which showed the test pattern which concerns on one modification. It is the figure which showed the test pattern which concerns on one modification.

  Embodiments of the present invention will be described below with reference to the drawings. Hereinafter, the direction in which the printing paper 9 is conveyed is referred to as a “first direction”, and the horizontal direction orthogonal to the first direction is referred to as a “second direction”.

<1. Configuration of recording apparatus>
FIG. 1 is a diagram conceptually showing the configuration of a recording apparatus 1 according to an embodiment of the present invention. FIG. 2 is a bottom view of the head unit 20. FIG. 3 is a bottom view of the nozzle head 22. FIG. 4 is a block diagram showing a control system of the recording apparatus 1.

  The recording apparatus 1 records a color image on the printing paper 9 by ejecting ink droplets from the plurality of head units 20 onto the printing paper 9 while conveying the printing paper 9 which is a long band-like recording medium. This is an ink jet printing apparatus. As illustrated in FIG. 1, the recording apparatus 1 includes a transport mechanism 10, four head units 20, an image acquisition unit 30, and a control unit 40.

  The transport mechanism 10 is a mechanism for transporting the printing paper 9 in a first direction that is the longitudinal direction thereof. The transport mechanism 10 according to the present embodiment includes an unwinding unit 11, a plurality of rollers 12, a winding unit 13, and a motor 14. Further, as conceptually shown in FIG. 1, a motor 14 serving as a power source is connected to the unwinding unit 11, the plurality of rollers 12, and the winding unit 13.

  When the motor 14 is driven, the unwinding unit 11, the plurality of rollers 12, and the winding unit 13 rotate. Then, the printing paper 9 is fed out from the unwinding unit 11 and conveyed to the winding unit 13 along the conveyance path constituted by the plurality of rollers 12. Each roller 12 guides the printing paper 9 to the downstream side of the conveyance path by rotating about the horizontal axis. Further, when the printing paper 9 comes into contact with the plurality of rollers 12, tension is applied to the printing paper 9. The transported printing paper 9 is collected to the winding unit 13.

  The four head units 20 are arranged above the transport path of the printing paper 9 with an interval in the first direction. The four head units 20 respectively eject yellow (Y), magenta (M), cyan (C), and black (K) ink droplets onto the upper surface of the printing paper 9. Since the structures of the four head units 20 are substantially the same, the structure of one head unit 20 will be described below.

  As shown in FIG. 2, the head unit 20 includes a housing 21 and a plurality of nozzle heads 22 fixed to the housing 21. Each nozzle head 22 has a discharge surface exposed on the lower surface of the housing 21. The plurality of nozzle heads 22 are arranged in a staggered manner (alternatingly in an oblique manner) along the width direction.

  The plurality of nozzle heads 22 includes a first nozzle head row 221 arranged in the second direction, and a second nozzle head row 222 arranged in the width direction at a position downstream of the first nozzle head row 221. Have The nozzle heads 22 of the first nozzle head row 221 and the nozzle heads 22 of the second nozzle head row 222 are alternately arranged in the second direction. As described above, the plurality of nozzle heads 22 are arranged in a staggered manner, so that the plurality of nozzle heads 22 are arranged at a high density in the second direction.

  Each nozzle head 22 has a plurality of nozzles 24 that eject ink droplets. As shown in FIG. 3, the plurality of nozzles 24 are two-dimensionally arranged on the ejection surface of each nozzle head 22. Specifically, each nozzle head 22 has a structure in which a plurality of nozzle rows 23 are arranged in the first direction. Each nozzle row 23 is composed of a plurality of nozzles 24 arranged linearly in the second direction.

  In the present embodiment, each nozzle head 22 has four nozzle rows 23 of a first nozzle row 231, a second nozzle row 232, a third nozzle row 233, and a fourth nozzle row 234. Each has 80 nozzles 24. That is, each nozzle head 22 has 320 nozzles 24. However, the number of nozzle rows 23 included in each nozzle head 22 and the number of nozzles 24 included in each nozzle row 23 are not limited thereto. Each nozzle head 22 may have other numbers of nozzle rows 23 such as two, eight, or sixteen, and each nozzle row 23 may have other numbers such as five, twenty, or 180. The nozzle 24 may be provided.

  The individual nozzles 24 in the nozzle head 22 are arranged with their positions shifted in the second direction, and one nozzle 24 is assigned to an area of 1 pixel width on the printing paper 9. On the other hand, in each nozzle row 23, the plurality of nozzles 24 are arranged at equal intervals in the second direction. Since one nozzle head 22 has four nozzle rows 23, two nozzles 24 adjacent in the second direction in each nozzle row 23 are arranged at positions separated by 4 pixels.

  When the recording apparatus 1 is in operation, ink droplets are ejected from the plurality of nozzles 24 onto the upper surface of the printing paper 9 while the printing paper 9 is being conveyed by the conveying mechanism 10. As described above, each head unit 20 includes a plurality of nozzle heads 22 each having a plurality of nozzles 24 arranged in a staggered manner in the width direction. For this reason, each head unit 20 can eject ink droplets over almost the entire width of the upper surface of the printing paper 9. Further, a color pattern is formed on the upper surface of the printing paper 9 by sequentially performing such ink droplet ejection processing in the four head units 20. That is, the transport device 10 and the four head units 20 constitute a recording unit that records a pattern such as an image on the printing paper 9.

  As shown in FIG. 1, the image acquisition unit 30 is disposed on the downstream side of each head unit 20. The image acquisition unit 30 acquires image data of a pattern recorded on the printing paper 9 by each head unit 20. In the present embodiment, the image acquisition unit 30 includes a line-shaped CCD camera, and photoelectrically reads all or part of the pattern recorded on the printing paper 9. Thereby, the image data of the pattern formed on the printing paper 9 by the four head units 20 is acquired.

  The control unit 40 is a part for controlling the operation of each unit in the recording apparatus 1. As conceptually shown in FIG. 1, the control unit 40 of the present embodiment is configured by a computer having an arithmetic processing unit 41 such as a CPU, a memory 42 such as a RAM, and a storage unit 43 such as a hard disk drive. Yes. The control unit 40 is electrically connected to the motor 14 of the transport mechanism 10, the four head units 20, and the image acquisition unit 30.

  The control unit 40 temporarily reads the computer program 431 and data 432 stored in the storage unit 43 into the memory 42, and the arithmetic processing unit 41 performs arithmetic processing based on the computer program 431 and data 432. The operation of each unit in the recording apparatus 1 is controlled. Thereby, the printing process in the recording apparatus 1 and the detection / adjustment process of the positional deviation amount described later proceed. Note that the control unit 40 may be configured by an electronic circuit.

  As shown in FIG. 4, the control unit 40 of the present embodiment includes a discharge control unit 44, a density data acquisition unit 45, and a detection unit 46 as processing units realized on software. The functions of the ejection control unit 44, the density data acquisition unit 45, and the detection unit 46 are realized by the arithmetic processing unit 41, the memory 42, and the storage unit 43 described above.

  The ejection control unit 44 controls ejection of ink droplets in each nozzle row 23. Accordingly, the ejection control unit 44 controls the ejection position of the ink droplets in each nozzle row 23. In the present embodiment, the control of the ink droplet ejection position is performed by controlling the ejection timing of the ink droplets from each nozzle 24. In the present embodiment, ink droplets are ejected from each nozzle row 23 while conveying the printing paper 9 at a constant speed. The printing paper 9 passes through the lower side of each nozzle row 23 in the order of the first nozzle row 231, the second nozzle row 232, the third nozzle row 233, and the fourth nozzle row 234. An ink droplet ejected from a predetermined nozzle 24 is received. Therefore, the landing position of the ink droplets in the first direction on the printing paper 9 is determined by the ejection timing of the ink droplets from each nozzle row 23. Therefore, the ejection control unit 44 can adjust the ejection timing of the ink droplets of the nozzle rows 23 to align the ejection positions in the first direction from the nozzle rows 23.

  The density data acquisition unit 45 acquires density distribution data in the first direction in the designated area based on the image data acquired by the image acquisition unit 30. Based on the density distribution data acquired by the density data acquisition unit 45, the detection unit 46 detects the amount of positional deviation in the first direction of the patterns recorded in the two areas to be compared.

<2. Printing flow>
Next, the flow of printing using the recording apparatus 1 will be described. FIG. 5 is a flowchart showing the flow of printing in the recording apparatus 1. Hereinafter, the flow of printing when a single straight line having a width of 1 pixel is recorded on the printing paper 9 using one nozzle head 22 will be described with reference to FIG.

  The recording apparatus 1 prints various patterns while conveying the printing paper 9. First, when the control unit 40 operates the motor 14, the transport mechanism 10 is driven, and the transport of the printing paper 9 is started (step S101).

  The recording apparatus 1 prints a target pattern by ejecting ink droplets from each nozzle row 23 while conveying the printing paper 9. In the present embodiment, since the first nozzle row 231 is located on the most upstream side in the first direction, the ink is in the order of the first nozzle row 231, the second nozzle row 232, the third nozzle row 233, and the fourth nozzle row 234. Droplet ejection is performed.

  First, ink droplets are ejected from the first nozzle row 231 at the first ejection time (step S102). The first ejection time is set in advance with reference to the target position for pattern printing.

  Next, ink droplets are ejected from the second nozzle row 232 at a second ejection time slightly delayed from the first ejection time (step S103). Subsequently, ink droplets are ejected from the third nozzle row 233 at a third ejection time slightly delayed from the second ejection time (step S103). Similarly, ink droplets are ejected from the fourth nozzle row 234 at a fourth ejection time slightly delayed from the third ejection time (step S104).

  The second discharge time, the third discharge time, and the fourth discharge time are stored in advance in the control unit 40 in a rewritable manner in consideration of the conveyance speed of the printing paper 9 with the first discharge time as a reference. As a result, the ink droplets ejected from each nozzle row 23 land on the same position in the first direction on the printing paper 9. As a result, a 1-pixel wide pattern extending in the second direction is formed.

  FIG. 6 is a diagram showing an example of a one-pixel-wide linear pattern recorded using the recording apparatus 1. 6A shows an example of a straight line pattern when there is no deviation in the ejection position in the first direction by each nozzle row 23. FIG. Further, (b) and (c) show examples of linear patterns in the case where there is a shift in the ejection position in the first direction by each nozzle row 23.

  As shown in FIG. 6A, the linear pattern includes a first dot D1 recorded by ink droplets ejected from the first nozzle row 231 and a second dot recorded by ink droplets ejected from the second nozzle row 232. D2, the third dot D3 recorded by the ink droplets ejected from the third nozzle row 233, and the fourth dot D4 recorded by the ink droplets ejected from the fourth nozzle row 234 are arranged in order.

  Each of the dots D1 to D4 is assigned to an area corresponding to one pixel. Therefore, the distance in the second direction between the center points of adjacent dots is a constant distance d0. Further, the distance in the second direction between the center points of the dots recorded by the same nozzle row 23 is a constant distance d1. In the present embodiment, since the number of nozzle rows arranged in the second direction is four, d1 is a distance four times d0.

  When the ejection timing of each nozzle row 23 is sufficiently adjusted and there is no deviation in the ejection position of each nozzle row 23, the dots D1 to D4 are the same in the first direction as shown in FIG. Placed in position. At this time, the width of the linear pattern in the first direction is the same as the width of each dot. On the other hand, when the ejection timing of each nozzle row 23 is not sufficiently adjusted, the ejection position of each nozzle row 23 is shifted, and as shown in FIGS. 6B and 6C, each of the dots D1 to D4. Are not aligned in the first direction. That is, the dots D2 to D4 are displaced in the first direction with respect to the dot D1. At this time, the width of the linear pattern in the first direction is larger than the width of each dot.

  In order to eliminate such a displacement in the first direction, it is necessary to adjust the ejection timing of each nozzle row 23. A method for adjusting the ejection timing of each nozzle row 23 will be described in detail below.

<3. Print test pattern and detect misalignment>
Next, test pattern printing and positional deviation amount detection in the recording apparatus 1 will be described. The test pattern visualizes the shift amount of the recording position during printing between the nozzle rows 23. FIG. 7 is a flowchart showing a flow of test pattern printing in the recording apparatus 1. FIG. 8 is a top view of the printing paper 9 before and after printing the test pattern.

  Here, as an example, the flow of test pattern printing and positional deviation amount detection when the first nozzle row 231 is the reference nozzle row and the second nozzle row 232 is the adjustment target nozzle row will be described below.

  First, a test pattern including the reference pattern P1 and the adjustment target pattern P2 is printed on the printing paper 9. When printing a test pattern, first, the control unit 40 sets a strip-like region F extending in the second direction at a predetermined position in the first direction on the printing paper 9 as a print pattern target position for the test pattern. And the discharge control part 44 of the control part 40 distinguishes the strip | belt-shaped area | region F into the reference | standard area | region F1 and the adjustment area | region F2 (step S201).

  In the present embodiment, as shown in FIG. 8, the ejection control unit 44 divides the belt-like region F corresponding to one nozzle head 22 into five in the second direction, and the reference region F1 and the adjustment region F2 are alternately arranged. The reference area F1 and the adjustment area F2 are distinguished so as to be arranged. In this manner, by alternately arranging the reference region F1 and the adjustment region F2, it is possible to make it less susceptible to the positional deviation in the first direction at both ends of the nozzle head 22 in the second direction. That is, it is possible to increase the detection accuracy of the positional deviation amount between the reference area F1 and the adjustment area F2.

  Next, the control unit 40 drives the motor 14 to operate the transport mechanism 10 and starts transporting the printing paper 9. Then, the ejection control unit 44 causes the predetermined nozzle 24 of the first nozzle row 231 to eject ink droplets at a predetermined first ejection time. Thereby, ink droplets are ejected with the reference area F1 as a target. As a result, the reference pattern P1 is recorded near the reference area F1 of the printing paper 9 (step S202).

  Even after the recording of the reference pattern P1, the printing paper 9 continues to be transported to the transport mechanism 10. For this reason, the printing paper 9 and the nozzle head 22 are relatively moved in the first direction (step S203).

  Subsequently, the ejection control unit 44 causes the predetermined nozzle 24 of the second nozzle row 232 to eject ink droplets at a predetermined second ejection time. Thereby, ink droplets are ejected with the adjustment area F2 as a target. As a result, the adjustment target pattern P2 is recorded in the vicinity of the adjustment area F2 of the printing paper 9 (step S204). Through the above steps S201 to S204, the test pattern P including the reference pattern P1 and the adjustment target pattern P2 is recorded on the printing paper 9, as shown in FIG.

  As shown in FIG. 8, the reference pattern P1 includes a plurality of first dots D1 formed by ink droplets ejected from the first nozzle row 231. The adjustment target pattern P2 includes a plurality of second dots D2 formed by ink droplets ejected from the second nozzle row 232. Here, the first dot D1 constituting the reference pattern P1 is referred to as a reference dot, and the second dot D2 constituting the adjustment target pattern P2 is referred to as an adjustment target dot. The plurality of reference dots and the plurality of adjustment target dots are each arranged along the second direction.

  As described above, the distance between the center points of the dots recorded by the same nozzle row is d1. Accordingly, the distance between the center point of one reference dot D1 and the center point of another reference dot D1 is a distance that is an integral multiple of d1. Similarly, the distance between the center point of one adjustment target dot D2 and the center point of another adjustment target dot D2 is a distance that is an integral multiple of d1. On the other hand, the distance between the center point of the reference dot D1 and the center point of the adjustment target dot D2 (for example, the distances d2 and d3 shown in FIG. 8) is different from an integer multiple of d1.

  In the present embodiment, since the first nozzle row 231 that is the reference nozzle row is positioned upstream of the second nozzle row 232 that is the adjustment target nozzle row, the reference pattern P1 is recorded before the adjustment target pattern P2. However, the present invention is not limited to this. For example, when the reference nozzle row is the fourth nozzle row 234, the band-like region F passes below the fourth nozzle row 234 after passing below the second nozzle row 232. In this case, after the adjustment target pattern is recorded by the second nozzle row 232 that is the adjustment target nozzle row, the printing paper 9 is conveyed downstream, and the reference pattern is recorded by the fourth nozzle row 234 that is the reference nozzle row. Is done.

  In the test pattern P of the present embodiment, the reference pattern P1 is not recorded in the adjustment area F2, but the present invention is not limited to this. Variations of the test pattern P will be described later.

  When the reference pattern P1 and the adjustment target pattern P2 are recorded on the printing paper 9, the recording apparatus 1 next detects the amount of positional deviation in the first direction between the reference pattern P1 and the adjustment target pattern P2.

  After step S <b> 204, the printing paper 9 is further transported, and the belt-like region F is transported to near the lower part of the image acquisition unit 30. Then, the image acquisition unit 30 acquires the image data 300 of the test pattern P including the reference pattern P1 and the adjustment target pattern P2 (Step S205).

  As shown in FIG. 4, the image data 300 acquired by the image acquisition unit 30 is delivered to the density data acquisition unit 45 of the control unit 40. The density data acquisition unit 45 analyzes the density distribution in the vicinity of the belt-like region F based on the image data 300. Then, the density data acquisition unit 45 acquires density distribution data 450 including density distribution data 451 in the first direction near the reference area F1 and density distribution data 452 in the first direction near the adjustment area F2 (step S206). ).

  Specifically, the density data acquisition unit 45 obtains the average value of the density in the second direction in each area near the reference area F1 and the adjustment area F2 of the image data 300. Accordingly, the density data acquisition unit 45 acquires density distribution data 450 including density distribution data 451 in the first direction near the reference area F1 and density distribution data 452 in the first direction near the adjustment area F2. In the present embodiment, the density distribution data 450 is an average value of the density in the second direction in each region, but may be an integrated value of the density in the second direction in each region.

  Then, the detection unit 46 of the control unit 40 detects the amount of displacement in the first direction of the adjustment target pattern P2 with respect to the reference pattern P1 based on the density distribution data 450 (step S207).

  FIG. 9 is a view showing a part of the image data 300 of the test pattern P and an example of the density distribution data 450. In FIG. 9, (a) is an example in which the reference pattern P1 and the adjustment target pattern P2 are coincident with each other in the first direction, and (b) and (c) are examples in which the adjustment target pattern P2 is relative to the reference pattern P1. This is an example of shifting to the upstream side.

  As shown in FIG. 9A, when the reference pattern P1 and the adjustment target pattern P2 coincide with each other in the first direction, the density distribution data 451 near the reference area F1 and the density distribution near the adjustment area F2. The data 452 matches. On the other hand, as shown in FIGS. 9B and 9C, as the deviation in the first direction between the reference pattern P1 and the adjustment target pattern P2 increases, the density distribution data 451 near the reference region F1 and the adjustment region F2 are increased. There is a deviation from the nearby density distribution data 452. Specifically, the barycentric positions of the density values of the density distribution data 451 and 452 are shifted. Therefore, by analyzing the density distribution data 450, it is possible to detect the amount of positional deviation in the first direction between the reference pattern P1 and the adjustment target pattern P2.

  In the present embodiment, the detection unit 46 calculates the barycentric coordinates of the density distributions of the respective density distribution data 451 and 452, and thereby the barycentric position x10 in the first direction of the reference pattern P1 and the first direction of the adjustment target pattern P2. Centroid position x20. Then, by detecting the shift amount and shift direction in the first direction between the centroid position x10 and the centroid position x20, the detection unit 46 calculates the shift amount 460 in the first direction of the adjustment target pattern P2 with respect to the reference pattern P1. To detect.

  In the present embodiment, the position shift amount in the first direction between the reference pattern P1 and the adjustment target pattern P2 is detected by calculating the center of gravity position in each of the regions F1 and F2 of the density distribution data 450. This is not the case. Variations in the detection method of the positional deviation amount 460 by the detection unit 46 will be described later.

  Finally, as shown in FIG. 4, the positional deviation amount 460 detected by the detection unit 46 is fed back to the discharge control unit 44 (step S208). Accordingly, the ejection control unit 44 adjusts the ejection time of each ink droplet in the nozzle row 23 based on the positional deviation amount 460 detected by the detection unit 46. That is, the ejection control unit 44 adjusts the ejection target position on the printing paper 9 for each nozzle row 23.

  Specifically, when the adjustment target pattern P2 is shifted to the upstream side of the reference pattern P1, the ejection time of the second nozzle row 232 that is the adjustment target nozzle row is advanced. When the adjustment target pattern P2 is shifted downstream from the reference pattern P1, the ejection time of the second nozzle row 232 that is the adjustment target nozzle row is delayed. The change amount of the discharge time is a time corresponding to the magnitude of the positional deviation amount 460. By considering the conveyance speed of the printing paper 9, the change amount of the ejection time corresponding to the positional deviation amount 460 can be determined.

  As described above, in the recording apparatus 1, printing is performed between the nozzle rows 23 by printing one test pattern P including the reference pattern P <b> 1 and the adjustment target pattern P <b> 2 and analyzing the density distribution data of the test pattern P. The positional deviation can be corrected.

<4. Types of test patterns>
Here, the types of test patterns will be described below.

<4-1. First test pattern>
First, with reference to FIG. 9, the test pattern P (hereinafter referred to as “first test pattern P”) used in the above embodiment will be described in detail below.

  When recording the first test pattern P, the ejection control unit 44 records the reference pattern P1 by ejecting ink droplets from the first nozzle array 231 that is the reference nozzle array to target the entire reference area F1. . At this time, ink droplets are not ejected from the first nozzle row to the adjustment region F2. The ejection control unit 44 records the adjustment target pattern P2 by ejecting ink droplets from the second nozzle row 232, which is the adjustment target nozzle row, targeting the entire adjustment region F2. At this time, ink droplets are not ejected from the second nozzle row 232 to the reference region F1.

  Thereby, in the first test pattern P, only the reference pattern P1 is recorded in the vicinity of the reference area F1, and only the adjustment target pattern P2 is recorded in the vicinity of the adjustment area F2. That is, the density distribution data 451 near the reference area F1 is density distribution data only for the reference pattern P1, and the density distribution data 452 near the adjustment area F2 is density distribution data only for the adjustment target pattern P2.

  For this reason, the position (hereinafter referred to as the lower end position) x11 of the downstream end of the density distribution range of the density distribution data 451 coincides with the lower end position of the reference pattern P1. The position (hereinafter referred to as the upper end position) x12 of the upstream end of the density distribution range of the density distribution data 451 coincides with the upper end position of the reference pattern P1. Further, the barycentric position x10 of the density distribution of the density distribution data 451 coincides with the barycentric position in the first direction of the reference pattern P1.

  Similarly, the lower end position x21 of the density distribution data 452 coincides with the lower end position of the adjustment target pattern P2, and the upper end position x22 of the density distribution data 452 coincides with the upper end position of the adjustment target pattern P2. Further, the gravity center position x20 of the density distribution of the density distribution data 452 coincides with the gravity center position in the first direction of the adjustment target pattern P2.

  In the first test pattern P, the density distribution data 451 and 452 represent the density distributions of only the patterns P1 and P2, so that the positional deviation amount detection process is easy. In addition, since the reference pattern P1 and the adjustment target pattern P2 do not overlap with each other, an error due to bleeding is less likely to occur even when the printing paper 9 in which ink droplets easily blur is used. Further, the expansion and contraction of the printing paper 9 due to the overlapping of the ink droplets hardly occurs.

<4-2. Second test pattern>
Next, the second test pattern will be described. FIG. 10 is a diagram showing the second test pattern Pa and its density distribution data 450a.

  When recording the second test pattern Pa, the ejection control unit 44 ejects ink droplets from the first nozzle array 231 that is the reference nozzle array to target the entire reference area F1 and the entire adjustment area F2, thereby causing the reference pattern to be ejected. P1 is recorded. The ejection control unit 44 records the adjustment target pattern P2 by ejecting ink droplets from the second nozzle row 232, which is the adjustment target nozzle row, targeting the entire adjustment region F2. At this time, ink droplets are not ejected from the second nozzle row 232 to the reference region F1.

  Thereby, in the second test pattern Pa, only the reference pattern P1 is recorded in the vicinity of the reference area F1, and both the reference pattern P1 and the adjustment target pattern P2 are recorded in the vicinity of the adjustment area F2. That is, the density distribution data 451a in the vicinity of the reference area F1 is density distribution data for only the reference pattern P1, and the density distribution data 452a in the vicinity of the adjustment area F2 is a density distribution of a pattern including both the reference pattern P1 and the adjustment target pattern P2. It becomes data.

  Therefore, the density distribution data 451a near the reference area F1 of the second test pattern Pa is the same as the density distribution data 451 near the reference area F1 of the first test pattern P. That is, the lower end position x11a of the density distribution data 451a matches the lower end position of the reference pattern P1, and the upper end position x12a of the density distribution data 451a matches the upper end position of the reference pattern P1. Further, the barycentric position x10a of the density distribution data 451a coincides with the barycentric position in the first direction of the reference pattern P1.

  As shown in FIG. 10A, when the positions of the reference pattern P1 and the adjustment target pattern P2 in the first direction are aligned, the lower end position x11a, the upper end position x12a, and the gravity center position x10a of the density distribution data 451a The lower end position x21a, the upper end position x22a, and the gravity center position x20a of the density distribution data 452a coincide with each other.

  On the other hand, as shown in FIGS. 10B and 10C, when the reference pattern P1 and the adjustment target pattern P2 are shifted in the first direction, the lower end position x21a of the density distribution data 452a is the reference pattern P1 and This coincides with the lower end position of one of the adjustment target patterns P2. In FIGS. 10B and 10C, since the adjustment target pattern P2 is shifted to the upstream side of the reference pattern P1, the lower end position x21a of the density distribution data 452a matches the lower end position of the reference pattern P1. . That is, the lower end position x21a of the density distribution data 452a matches the lower end position x11a of the density distribution data 451a. Further, the upper end position x22a of the density distribution data 452a coincides with the other upper end position of the reference pattern P1 and the adjustment target pattern P2. In FIGS. 10B and 10C, the upper end position x22a of the density distribution data 452a coincides with the upper end position of the adjustment target pattern P2.

  Thus, at least one of the lower end position x21a and the upper end position x22a of the density distribution data 452a matches the lower end position x11a or the upper end position x12a of the density distribution data 451a.

  In addition, since the reference pattern P1 and the adjustment target pattern P2 are distributed at the same density in the vicinity of the adjustment region F2, the gravity center position of the density distribution data 452a is the same as the gravity center position of the reference pattern P1 in the first direction and the adjustment target. This is the midpoint of the center of gravity of the pattern P2 in the first direction.

  In the second test pattern Pa, both the reference pattern P1 and the adjustment target pattern P2 are recorded in the vicinity of the adjustment area F2. For this reason, when the reference pattern P1 and the adjustment target pattern P2 are shifted in the first direction, they appear darker and thicker than the reference region F1 with the naked eye. Even when the reference pattern P1 and the adjustment target pattern P2 are not shifted in the first direction, they appear darker than the reference region F1 with the naked eye. For this reason, the second test pattern Pa makes it easy to visually determine the distinction between the reference area F1 and the adjustment area F2. Therefore, it is easy to visually confirm the recording position deviation between the reference pattern P1 and the adjustment target pattern P2.

<4-3. Third test pattern>
Next, the third test pattern will be described. FIG. 11 is a diagram showing the third test pattern Pb and its density distribution data 450b.

  When recording the third test pattern, the ejection control unit 44 ejects ink droplets from the first nozzle array 231 that is the reference nozzle array to target the entire reference area F1 and a part of the adjustment area F2. The reference pattern P1 is recorded. Further, the ejection control unit 44 records the adjustment target pattern P2 by ejecting ink droplets from the second nozzle row 232, which is the adjustment target nozzle row, targeting another part of the adjustment region F2. At this time, ink droplets are not ejected from the second nozzle row 232 to the reference region F1.

  In the example of FIG. 11, each of the first nozzle row 231 and the second nozzle row 232 ejects ink droplets from every other nozzle and ejects from each nozzle row 23 with the adjustment region F2 as a target. It is set so that ink droplets do not overlap on the printing paper 9.

  As a result, in the second test pattern Pb, only the reference pattern P1 is recorded in the vicinity of the reference area F1, and both the reference pattern P1 and the adjustment target pattern P2 are recorded in the vicinity of the adjustment area F2. That is, the density distribution data 451b near the reference area F1 is density distribution data only for the reference pattern P1, and the density distribution data 452b near the adjustment area F2 is a density distribution of a pattern including both the reference pattern P1 and the adjustment target pattern P2. It becomes data.

  Therefore, the density distribution data 451b near the reference area F1 of the third test pattern Pb is the same as the density distribution data 451 near the reference area F1 of the first test pattern P. That is, the lower end position x11b of the density distribution data 451b matches the lower end position of the reference pattern P1, and the upper end position x12b of the density distribution data 451b matches the upper end position of the reference pattern P1. Further, the barycentric position x10b of the density distribution data 451b matches the barycentric position in the first direction of the reference pattern P1.

  As shown in FIG. 11A, when the positions of the reference pattern P1 and the adjustment target pattern P2 in the first direction are aligned, the lower end position x11b, the upper end position x12b, and the gravity center position x10b of the density distribution data 451b The lower end position x21b, the upper end position x22b, and the center of gravity position x20b of the density distribution data 452b coincide with each other.

  On the other hand, as shown in FIGS. 11B and 11C, when the reference pattern P1 and the adjustment target pattern P2 are displaced in the first direction, the lower end position x21b of the density distribution data 452b is the reference pattern P1 and This coincides with the lower end position of one of the adjustment target patterns P2. In FIGS. 11B and 11C, since the adjustment target pattern P2 is shifted to the upstream side of the reference pattern P1, the lower end position x21b of the density distribution data 452b matches the lower end position of the reference pattern P1. . That is, the lower end position x21b of the density distribution data 452b matches the lower end position x11b of the density distribution data 451b. Further, the upper end position x22b of the density distribution data 452b coincides with the other upper end position of the reference pattern P1 and the adjustment target pattern P2. 11B and 11C, the upper end position x22b of the density distribution data 452b matches the upper end position of the adjustment target pattern P2.

  Thus, at least one of the lower end position x21b and the upper end position x22b of the density distribution data 452b matches the lower end position x11b or the upper end position x12b of the density distribution data 451b.

  In addition, since the reference pattern P1 and the adjustment target pattern P2 are distributed at the same density in the vicinity of the adjustment region F2, the gravity center position of the density distribution data 452b is the same as the gravity center position of the reference pattern P1 in the first direction and the adjustment target. This is the midpoint of the center of gravity of the pattern P2 in the first direction. In FIG. 11, the reference pattern P1 and the adjustment target pattern P2 are distributed at the same density in the vicinity of the adjustment region F2. However, if the distribution density of the reference pattern P1 and the adjustment target pattern P2 is different, the density distribution data The position of the center of gravity of 452b is a position corresponding to the ratio of the distribution densities of both patterns P1 and P2.

  In the third test pattern Pb, both the reference pattern P1 and the adjustment target pattern P2 are recorded in the vicinity of the adjustment area F2. Therefore, when the reference pattern P1 and the adjustment target pattern P2 are shifted in the first direction, the line appears to be thicker than the reference region F1 with the naked eye. For this reason, when the reference pattern P1 and the adjustment target pattern P2 are deviated, the third test pattern Pb can easily visually determine the distinction between the reference area F1 and the adjustment area F2. Therefore, it is easy to visually confirm the recording position deviation between the reference pattern P1 and the adjustment target pattern P2.

  Further, even if the deviation between the reference pattern P1 and the adjustment target pattern P2 is small or not, the reference pattern P1 and the adjustment target pattern P2 are difficult to overlap. As a result, bleeding due to overlapping patterns is suppressed. Therefore, accurate concentration distribution data can be obtained as compared with the case where bleeding occurs. Further, the expansion and contraction of the printing paper 9 due to the overlapping of the ink droplets hardly occurs.

<5. Misalignment detection method>
Next, the positional deviation amount detection method will be described in detail. As described above, the detection unit 46 calculates the first of the reference pattern P1 and the adjustment target pattern P2 from the density distribution data 451 near the reference area F1 and the density distribution data 452 near the adjustment area F2 included in the density distribution data 450. A displacement amount in one direction is detected. Hereinafter, a method of detecting the positional deviation amount 460 in the detection unit 46 will be described.

<5-1. Detection by center of gravity position>
In the above embodiment, the detection unit 46 detects the positional deviation amount 460 in the first direction between the reference pattern P1 and the adjustment target pattern P2 by analyzing the center of gravity position of the density distribution data 450. Hereinafter, a method for detecting the amount of displacement 460 based on the position of the center of gravity according to the type of test pattern will be described.

  In the first test pattern P shown in FIG. 9, the barycentric position x10 of the density distribution data 451 near the reference area F1 matches the barycentric position of the reference pattern P1 in the first direction. Further, the barycentric position x20 of the density distribution data 452 near the adjustment area F2 matches the barycentric position in the first direction of the adjustment target pattern P2.

  Therefore, the positional deviation amount of the centroid position x20 with respect to the centroid position x10 matches the positional deviation amount 460 of the adjustment target pattern P2 with respect to the reference pattern P1. As described above, in the first test pattern P, the positional deviation amount 460 in the first direction between the reference pattern P1 and the adjustment target pattern P2 can be detected as the positional deviation amount of the centroid position x20 with respect to the centroid position x10.

  In the second test pattern Pa shown in FIG. 10, the barycentric position x10a of the density distribution data 451 near the reference area F1 coincides with the barycentric position of the reference pattern P1 in the first direction. On the other hand, in the vicinity of the adjustment region F2, as described above, the reference pattern P1 and the adjustment target pattern P2 are distributed at the same density, so that the center of gravity position x20a of the density distribution data 452a is the center of gravity of the reference pattern P1 in the first direction. This is the midpoint between the position and the barycentric position in the first direction of the adjustment target pattern P2.

  That is, the displacement amount of the gravity center position x20a with respect to the gravity center position x10a is half of the displacement amount 460 of the adjustment target pattern P2 with respect to the reference pattern P1. As described above, in the second test pattern Pa, the positional deviation amount 460 in the first direction between the reference pattern P1 and the adjustment target pattern P2 is detected as twice the positional deviation amount of the centroid position x20a with respect to the centroid position x10a. it can. However, in this case, since the measurement error included in the positional deviation amount of the centroid position x20a with respect to the centroid position x10a is doubled, the detection accuracy of the positional deviation amount 460 is lower than that of the first test pattern P.

  As shown in FIG. 11, the third test pattern Pb is the same as the second test pattern Pa when the reference pattern P1 and the adjustment target pattern P2 are distributed at the same density in the vicinity of the adjustment region F2. When the density of the reference pattern P1 and the adjustment target pattern P2 in the vicinity of the adjustment region F2 is different, it is necessary to consider the density ratio between the reference pattern P1 and the adjustment target pattern P2, and the analysis in the detection unit 46 is complicated. It becomes. For this reason, when the density of the reference pattern P1 and the adjustment target pattern P2 in the vicinity of the adjustment region F2 is different, detection can be performed with higher accuracy by performing detection based on a distribution width described later.

<5-2. Detection by distribution width>
The detection unit 46 can detect the positional deviation amount 460 in the first direction between the reference pattern P1 and the adjustment target pattern P2 by analyzing the distribution width of the density distribution data 450. Hereinafter, a method for detecting the positional deviation amount 460 based on the distribution width according to the type of the test pattern will be described.

  In the first test pattern shown in FIG. 9, as described above, the lower end position x11 and the upper end position x12 of the density distribution data 451 coincide with the lower end position and the upper end position of the reference pattern P1, respectively. Further, the lower end position x21 and the upper end position x22 of the density distribution data 452 respectively coincide with the lower end position and the upper end position of the adjustment target pattern P2.

  Accordingly, the positional deviation amount of the lower end position x21 with respect to the lower end position x11 matches the positional deviation amount of the adjustment target pattern P2 with respect to the reference pattern P1. Further, the amount of positional deviation of the upper end position x22 with respect to the upper end position x12 matches the amount of positional deviation 460 of the adjustment target pattern P2 with respect to the reference pattern P1. Thus, in the first test pattern P, the positional deviation amount 460 between the reference pattern P1 and the adjustment target pattern P2 in the first direction is the positional deviation amount of the lower end position x21 with respect to the lower end position x11 or the upper end position with respect to the upper end position x12. It can be detected as a positional deviation amount of the position x22.

  Further, in the first test pattern P, the positional deviation amount 460 between the reference pattern P1 and the adjustment target pattern P2 in the first direction is the positional deviation amount of the lower end position x21 with respect to the lower end position x11 and the upper end position x22 with respect to the upper end position x12. You may detect as an average with positional offset amount. In this case, the influence of the measurement error is smaller than only the positional deviation amount between the upper end positions or only the positional deviation amount between the lower end positions.

  In the second test pattern Pa shown in FIG. 10, as described above, at least one of the lower end position x21a and the upper end position x22a of the density distribution data 452a matches the lower end position x11a or the upper end position x12a of the density distribution data 451a.

  When the lower end position x11a and the lower end position x21a coincide with each other, the positional deviation amount of the upper end position x22a with respect to the upper end position x12a coincides with the positional deviation amount 460 of the adjustment target pattern P2 with respect to the reference pattern P1. Similarly, when the upper end position x12a and the upper end position x22a coincide with each other, the positional deviation amount of the lower end position x21a with respect to the lower end position x11a coincides with the positional deviation amount 460 of the adjustment target pattern P2 with respect to the reference pattern P1.

  Thus, in the second test pattern Pa, the positional deviation amount 460 in the first direction between the reference pattern P1 and the adjustment target pattern P2 is the positional deviation amount of the lower end position x21a with respect to the lower end position x11a or the upper end position with respect to the upper end position x12a. It can be detected as a positional deviation amount of the position x22a.

  In the third test pattern Pb shown in FIG. 11, like the second test pattern Pa, at least one of the lower end position x21b and the upper end position x22b of the density distribution data 452b is the lower end position x11b or the upper end position x12b of the density distribution data 451b. Match.

  Therefore, in the third test pattern Pb, similarly to the second test pattern Pa, the positional deviation amount 460 in the first direction between the reference pattern P1 and the adjustment target pattern P2 is set to the positional deviation amount of the lower end position x21b with respect to the lower end position x11b, or The amount of displacement of the upper end position x22b with respect to the upper end position x12b can be detected.

  The detection of the lower end position and the upper end position of each density distribution data of the density distribution data 450 is performed by providing a threshold value, for example. In FIG. 9, as indicated by density distribution data 451 in (a), a range in which the density value is equal to or greater than a predetermined threshold c is defined as a pattern distribution range, and its lower end position is the lower end position x11 of the density distribution data 451 and its upper end. The position may be detected as the upper end position x12 of the density distribution data 451.

  As described above, when detecting the lower end position and the upper end position of each density distribution data of the density distribution data 450 by providing threshold values, different threshold values may be set according to the color of the ink droplet used for recording the test pattern. Good.

<6. Modification>
Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

<6-1. Test pattern array>
In the above embodiment, as shown in FIG. 8, one band-like region F is divided into five in the second direction, and the reference region and the adjustment region are alternately arranged. However, the present invention is not limited to this. I can't.

  In the following, examples of test pattern arrangements will be described. For convenience of explanation, only the reference pattern is recorded in the reference area and only the corresponding adjustment target pattern is recorded in the adjustment area. A description will be given using one test pattern. However, the following arrangement can also be applied to other test patterns such as the second test pattern.

  FIG. 12 is a diagram showing an arrangement of test patterns according to a modification. The test pattern Pc is obtained by recording test patterns for one reference nozzle row and one adjustment target nozzle row of the nozzle head in two belt-like regions F.

  In the example of FIG. 12, two band-like regions F corresponding to one nozzle head are each divided into five in the second direction, and reference regions F1 and adjustment regions F2 are alternately arranged. In the two belt-like regions F, the reference regions F1 or the adjustment regions F2 are arranged so as not to overlap each other in the first direction.

  In this way, the position in the first direction can be compared between the reference pattern for the entire reference nozzle array and the adjustment target pattern for the entire adjustment target nozzle array. Thereby, it is possible to further increase the detection accuracy of the positional deviation amount between the reference pattern and the adjustment target pattern.

  FIG. 13 is a diagram showing an arrangement of test patterns according to another modification. In the example of FIG. 13, one band-like region F includes a reference region F1, a first adjustment region F2, a second adjustment region F3, and a third adjustment region F4. The reference region F1 is a target region for ejecting ink droplets from a reference nozzle row (for example, the first nozzle row). The first adjustment region F2 is a target region for ejecting ink droplets from a first adjustment nozzle row (for example, the second nozzle row). The second adjustment region F3 and the third adjustment region F4 are targets for ejecting ink droplets from the second adjustment nozzle row (for example, the third nozzle row) and the third adjustment nozzle row (for example, the fourth nozzle row), respectively. It is an area.

  In the example of FIG. 13, a single band-shaped region F includes a reference region F1 and a plurality of adjustment regions F2 to F4 corresponding to a plurality of different nozzle rows. The amount of displacement of the nozzle row can be detected. Therefore, the amount of ink used for printing the test pattern can be further suppressed.

<6-2. Other variations>
Further, the recording apparatus of the above embodiment has a recording unit that performs recording on a recording medium, an image acquisition unit, a density data acquisition unit, and a detection unit, but the present invention is not limited to this. Absent. The recording apparatus of the present invention has only a recording unit that performs recording on a recording medium, and the image acquisition unit, the density data acquisition unit, and the detection unit belong to other apparatuses independent of the recording apparatus. It may be.

  For example, the recording apparatus may be realized by an inkjet printer, the image acquisition unit may be realized by a scanner, and the density data acquisition unit and detection unit may be realized by a personal computer. Further, the recording apparatus may further include an input unit, and the amount of positional deviation detected by the detection unit may be input from the outside.

  In the above embodiment, the position of the nozzle head 22 is fixed, and the printing paper 9 is moved in the first direction with respect to the nozzle head 22. However, the position of the printing paper 9 may be fixed, and the nozzle head 22 may be moved in the first direction with respect to the printing paper 9. That is, the relative movement means of the present invention may be any means that relatively moves the nozzle head and the recording medium in the first direction.

  The recording apparatus 1 records an image on the printing paper 9 as a recording medium. However, the recording apparatus of the present invention may record a pattern such as an image on a sheet-like recording medium (for example, a resin film) other than general paper.

  Moreover, you may combine suitably each element which appeared in said embodiment and modification in the range which does not produce inconsistency.

DESCRIPTION OF SYMBOLS 1 Recording device 9 Printing paper 10 Conveyance mechanism 20 Head unit 22 Nozzle head 23 Nozzle row 24 Nozzle 30 Image acquisition part 40 Control part 44 Discharge control part 45 Density data acquisition part 46 Detection part 231 1st nozzle row 232 2nd nozzle row 233 Third nozzle row 234 Fourth nozzle row 300 Image data 450, 450a, 450b, 451, 451a, 451b, 452, 452a, 452b Density distribution data 460 Position shift amount F Band-like region F1 Reference region F2, F3, F4 Adjustment region F2 -F4 Adjustment area P, Pa, Pb Test pattern P1 Reference pattern P2 Adjustment target pattern x10, x10a, x10b, x20, x20a, x20b Center of gravity position x11, x11a, x11b, x21, x21a, x21b Lower end position x12, x12a, x 2b, x22, x22a, x22b the upper end position

Claims (21)

A recording apparatus for recording characters and images on the recording medium by discharging droplets onto the recording medium,
A nozzle head having a plurality of nozzles for discharging droplets;
A relative movement means for relatively moving the recording medium and the nozzle head in a first direction;
A discharge controller for controlling the discharge of droplets in the nozzle;
Have
The nozzle head has a structure in which a plurality of nozzle rows composed of the plurality of nozzles arranged linearly in a second direction orthogonal to the first direction are arranged in the first direction;
The discharge controller is
A band-like region extending in the second direction at a predetermined position in the first direction on the recording medium is distinguished into a reference region and an adjustment region,
A reference pattern is recorded by ejecting droplets from one reference nozzle row included in the plurality of nozzle rows, targeting the entire reference region and at least a part of the adjustment region ,
An adjustment target pattern is recorded by ejecting droplets from the adjustment target nozzle row included in the plurality of nozzle rows other than the reference nozzle row, targeting the adjustment region.
Recording device. The recording apparatus according to claim 1,
  The discharge controller is
    From the reference nozzle row, the reference pattern is recorded by ejecting droplets targeting the entire reference area and a part of the adjustment area,
    A recording apparatus that records the adjustment target pattern by ejecting liquid droplets from the adjustment target nozzle row targeting another part of the adjustment region. The recording apparatus according to claim 1,
  The discharge controller is
    From the reference nozzle row, the reference pattern is recorded by ejecting droplets targeting the entire reference area and the entire adjustment area,
    A recording apparatus that records an adjustment target pattern by ejecting droplets from the adjustment target nozzle row to target the entire adjustment region. A recording apparatus according to any one of claims 1 to 3,
  The nozzle head has three or more nozzle rows,
  The discharge control unit distinguishes the band-shaped region into the reference region, the first adjustment region, and the second adjustment region,
  The first adjustment area is the adjustment area, and is a target area for discharging droplets from the first adjustment target nozzle array that is one of the adjustment target nozzle arrays,
  The recording apparatus, wherein the second adjustment area is the adjustment area and is a target area for ejecting droplets from a second adjustment target nozzle array that is another one of the adjustment target nozzle arrays. A recording apparatus for recording characters and images on the recording medium by discharging droplets onto the recording medium,
  A nozzle head having a plurality of nozzles for discharging droplets;
  A relative movement means for relatively moving the recording medium and the nozzle head in a first direction;
  A discharge controller for controlling the discharge of droplets in the nozzle;
Have
  The nozzle head has a structure in which a plurality of nozzle rows composed of the plurality of nozzles arranged linearly in a second direction orthogonal to the first direction are arranged in the first direction;
  The discharge controller is
    A band-like region extending in the second direction at a predetermined position in the first direction on the recording medium is distinguished into a plurality of reference regions and a plurality of adjustment regions,
    From one reference nozzle row included in the plurality of nozzle rows, by ejecting droplets targeting at least the reference region, a reference pattern is recorded,
    From the adjustment target nozzle row included in the plurality of nozzle rows other than the reference nozzle row, the adjustment target pattern is recorded by ejecting droplets targeting the adjustment region,
  The plurality of adjustment areas include a plurality of first adjustment areas,
  The first adjustment area is the adjustment area, and is a target area for discharging droplets from the first adjustment target nozzle array that is one of the adjustment target nozzle arrays,
  The plurality of reference regions and the plurality of first adjustment regions are alternately arranged in the second direction.
Recording device. A recording apparatus according to any one of claims 1 to 5,
  An image acquisition unit for acquiring image data of the reference pattern and the adjustment target pattern;
  A density data acquisition unit that acquires density distribution data in the first direction near the reference area and the adjustment area based on the image data;
  A detection unit that detects a displacement amount of the reference pattern and the adjustment target pattern in the first direction based on the density distribution data;
A recording apparatus further comprising: The recording apparatus according to claim 6,
  The detection unit is based on the concentration distribution data.
    A gravity center position in the first direction of the density distribution data in the vicinity of the reference region;
    A gravity center position in the first direction of the density distribution data in the vicinity of the adjustment region;
The recording apparatus detects the amount of positional deviation by comparing the two. The recording apparatus according to claim 6,
  The detection unit is based on a predetermined threshold value.
    A distribution region of the concentration distribution data in the vicinity of the reference region;
    A distribution region of the density distribution data in the vicinity of the adjustment region;
The recording apparatus detects the amount of positional deviation by comparing the two. A recording apparatus according to any one of claims 6 to 8,
  The recording apparatus, wherein the ejection control unit adjusts each ejection target position of the nozzle row based on the displacement amount detected by the detection unit.   The recording medium having a test pattern recorded using a recording device that records characters and images on the recording medium by discharging droplets onto the recording medium,
  The recording device comprises:
    A nozzle head having a plurality of nozzles for discharging droplets;
    A relative movement means for relatively moving the recording medium and the nozzle head in a first direction;
Have
  The nozzle head has a structure in which a plurality of nozzle rows composed of a plurality of nozzles arranged in a straight line at equal intervals in a second direction orthogonal to the first direction are arranged in the first direction;
  The test pattern is disposed on a belt-like region extending in the second direction at a predetermined position in the first direction on the recording medium,
  The test pattern is
    A plurality of reference dots arranged in the second direction;
    A plurality of adjustment target dots arranged in the second direction;
Have
  The distance between the center point of one of the reference dots and the center point of the other reference dot is a distance that is an integral multiple of a predetermined distance.
  The distance between the center point of one of the adjustment target dots and the center point of the other adjustment target dot is a distance that is an integral multiple of the predetermined distance.
  The distance between the center point of one reference dot and the center point of one adjustment target dot is different from a distance that is an integral multiple of the predetermined distance;
  The strip region is
    A reference region in which only a plurality of the reference dots are arranged; and
    An adjustment region in which a plurality of reference dots and a plurality of adjustment target dots are arranged;
A recording medium. The recording medium according to claim 10, wherein
The plurality of reference dots are arranged in the whole reference region and a part of the adjustment region,
A plurality of the adjustment target dots is a recording medium arranged in another part of the adjustment area. The recording medium according to claim 10, wherein
The plurality of reference dots are arranged in the entire reference area and the entire adjustment area,
A plurality of the adjustment target dots are arranged on the entire adjustment area. The recording medium having a test pattern recorded using a recording device that records characters and images on the recording medium by discharging droplets onto the recording medium,
  The recording device comprises:
    A nozzle head having a plurality of nozzles for discharging droplets;
    A relative movement means for relatively moving the recording medium and the nozzle head in a first direction;
Have
  The nozzle head has a structure in which a plurality of nozzle rows composed of a plurality of nozzles arranged in a straight line at equal intervals in a second direction orthogonal to the first direction are arranged in the first direction;
  The test pattern is disposed on a belt-like region extending in the second direction at a predetermined position in the first direction on the recording medium,
  The test pattern is
    A plurality of reference dots arranged in the second direction;
    A plurality of adjustment target dots arranged in the second direction;
Have
  The distance between the center point of one of the reference dots and the center point of the other reference dot is a distance that is an integral multiple of a predetermined distance.
  The distance between the center point of one of the adjustment target dots and the center point of the other adjustment target dot is a distance that is an integral multiple of the predetermined distance.
  The distance between the center point of one reference dot and the center point of one adjustment target dot is different from a distance that is an integral multiple of the predetermined distance;
  The strip region is
    A plurality of reference areas in which only a plurality of the reference dots are arranged; and
    A plurality of adjustment areas in which a plurality of adjustment target dots are arranged; and
Have
  The plurality of reference areas and the plurality of adjustment areas are recording media that are alternately arranged in the second direction. A recording method using a recording apparatus that records characters and images on the recording medium by discharging droplets onto the recording medium,
  The recording device comprises:
    A nozzle head having a plurality of nozzles for discharging droplets;
    A relative movement means for relatively moving the recording medium and the nozzle head in a first direction;
Have
  The nozzle head has a structure in which a plurality of nozzle rows composed of the plurality of nozzles arranged linearly in a second direction orthogonal to the first direction are arranged in the first direction;
  a) a preparation step of distinguishing a band-like region extending in the second direction at a predetermined position in the first direction on the recording medium into a reference region and an adjustment region;
  b) After step a), a reference pattern is ejected from one reference nozzle array included in the plurality of nozzle arrays, targeting the reference area and at least a part of the adjustment area. Recording a reference pattern, and
  c) After the step a), the adjustment target pattern is recorded by ejecting droplets from the adjustment target nozzle rows included in the plurality of nozzle rows other than the reference nozzle row, targeting the adjustment region. An adjustment target pattern recording process;
  d) a relative movement step of relatively moving the recording medium and the nozzle head in a first direction between the step b) and the step c);
Including a recording method. 15. The recording method according to claim 14, wherein
In step b), droplets are ejected from the reference nozzle row targeting the entire reference region and a part of the adjustment region,
A recording method in which, in the step c), droplets are ejected from the adjustment target nozzle row targeting another part of the adjustment region. 15. The recording method according to claim 14, wherein
In step b), droplets are ejected from the reference nozzle row targeting the entire reference area and the entire adjustment area,
In the step c), a droplet is ejected from the adjustment target nozzle row targeting the entire adjustment region. A recording method using a recording apparatus that records characters and images on the recording medium by discharging droplets onto the recording medium,
  The recording device comprises:
    A nozzle head having a plurality of nozzles for discharging droplets;
    A relative movement means for relatively moving the recording medium and the nozzle head in a first direction;
Have
  The nozzle head has a structure in which a plurality of nozzle rows composed of the plurality of nozzles arranged linearly in a second direction orthogonal to the first direction are arranged in the first direction;
  a) a preparation step of distinguishing a band-like region extending in the second direction at a predetermined position in the first direction on the recording medium into a reference region and an adjustment region;
  b) After the step a), a reference pattern recording step of recording a reference pattern by discharging droplets from one reference nozzle row included in the plurality of nozzle rows targeting at least the reference region; ,
  c) After the step a), the adjustment target pattern is recorded by ejecting droplets from the adjustment target nozzle rows included in the plurality of nozzle rows other than the reference nozzle row, targeting the adjustment region. An adjustment target pattern recording process;
  d) a relative movement step of relatively moving the recording medium and the nozzle head in a first direction between the step b) and the step c);
Including
  In the step a), the band-like region is distinguished into a plurality of reference regions and a plurality of adjustment regions,
  The recording method, wherein the plurality of reference areas and the plurality of adjustment areas are alternately arranged in the second direction. A recording method according to any one of claims 14 to 17,
  e) an image acquisition step of acquiring image data of the reference pattern and the adjustment target pattern after the steps b) to d);
  f) A density data acquisition step for acquiring density distribution data in the first direction near the reference region and the adjustment region based on the image data after the step e);
  g) After the step f), based on the density distribution data, a detection step of detecting a positional deviation amount in the first direction between the reference pattern and the adjustment target pattern;
A recording method further comprising: The recording method according to claim 18, wherein
  In the step g), based on the density distribution data, the positional deviation amount is obtained by acquiring the center-of-gravity position of the reference pattern in the first direction and the center-of-gravity position of the adjustment target pattern in the first direction. Detecting the recording method. The recording method according to claim 18, wherein
  In step g), based on a predetermined threshold,
    A distribution region of the concentration distribution data in the vicinity of the reference region;
    A distribution region of the density distribution data in the vicinity of the adjustment region;
A recording method in which the amount of positional deviation is detected by comparing. A recording method according to any one of claims 18 to 20, comprising:
  h) After the step g), a feedback step of adjusting the relative movement amount in the step d) based on the positional deviation amount.
A recording method further comprising:

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