JP6262964B2 - Image recording apparatus and image recording method - Google Patents

Description

  The present invention relates to an image recording apparatus and an image recording method for recording an image on a sheet-like recording medium.

  2. Description of the Related Art Conventionally, there has been known an ink jet type image recording apparatus that records an image on a printing paper by ejecting ink from a plurality of recording heads while conveying the sheet-like printing paper. In this type of image recording apparatus, different colors of ink are ejected from a plurality of recording heads. A color image is formed by the ink of each color adhering to the printing paper. A conventional inkjet image recording apparatus is described in, for example, Patent Document 1.

JP 2004-268361 A

  In the image recording apparatus described above, when ink is ejected onto the upper surface of the printing paper, the ink permeates the printing paper, causing a slight expansion and contraction of the printing paper. When the next ink is ejected onto the printing paper in this state, the positional relationship between the previous ink ejection position and the subsequent ink ejection position may deviate from the ideal positional relationship. Such relative displacement of the ejection position can be a factor that degrades the image quality of the printed matter.

  In the conventional image recording apparatus, a so-called registration mark is printed at the corner of the printing paper, and ink of each color is discharged using the registration mark as a reference, thereby preventing the displacement of the discharge position due to the expansion and contraction of the printing paper. However, in this method, there is a problem that a sensor for measuring the registration mark is necessary and a processing process increases due to the measurement of the registration mark.

  The present invention has been made in view of such circumstances, and the positional relationship between a plurality of color component images recorded on a recording medium without using registration marks is an ideal positional relationship at least in the transport direction. An object of the present invention is to provide an image recording apparatus and an image recording method capable of suppressing deviation from the above.

In order to solve the above problems, a first invention of the present application is an image recording apparatus that records an image on a sheet-like recording medium, and includes a plurality of recording heads, the plurality of recording heads, and the recording medium. A transport mechanism that relatively moves along a transport direction parallel to an arrangement direction of the plurality of recording heads, and a control unit that controls the plurality of recording heads and the transport mechanism based on image data, The plurality of recording heads include a plurality of nozzles arranged in parallel with a horizontal direction orthogonal to the transport direction, and a first head that ejects droplets of the first ink from the nozzles toward the recording medium; And a second head for ejecting droplets of a second ink having a color different from that of the first ink toward the recording medium on the downstream side in the transport direction from the first head. parts, the first And the ink discharge amount, the a storage unit for storing a correspondence relationship between the transport direction of the expansion and contraction amount of the recording medium, based on the first ink component image included in the image data, the first head Rutotomoni to eject droplets of the first ink, on the basis of the first ink component image, wherein the nozzles of the first head calculates the discharge amount of the first ink in each recording area in charge, it is calculated and discharge amount of the first ink, the read from the storage unit based on the correspondence relation, for each of the recording area, determining the amount of extension of the transport direction of the recording medium by the first ink, Based on the determined amount of expansion and contraction and the second ink component image included in the image data, the second head causes the second ink droplets to be ejected.

  According to a second aspect of the present invention, in the image recording apparatus according to the first aspect, the transport mechanism moves the recording medium with respect to the plurality of recording heads fixedly arranged.

  According to a third aspect of the present invention, the image recording apparatus according to the first or second aspect further includes a tension applying unit that applies a tension in the transport direction to the recording medium.

A fourth invention of the present application is the image recording apparatus according to any one of the first to third inventions, wherein the control unit deforms the second ink component image according to the expansion / contraction amount, and the deformed second ink component image. Based on the two-ink component image, the second head is caused to eject droplets of the second ink.

According to a fifth aspect of the present invention, in the image recording apparatus according to any one of the first to third aspects, the control unit determines a discharge timing of the second ink droplet from the second head based on the expansion / contraction amount. It changes based on the correction time corresponding to.

A sixth invention of the present application is the image recording apparatus according to any one of the first to fifth inventions, wherein the control unit is configured to cause the second ink liquid to be ejected from the second head in accordance with the expansion / contraction amount. The number of droplets discharged in the transport direction is changed.

According to a seventh aspect of the present invention, a plurality of recording heads and a sheet-like recording medium are moved relative to each other along a conveying direction parallel to an arrangement direction of the plurality of recording heads, and ink is discharged from the plurality of recording heads. An image recording method for recording an image on the recording medium by discharging droplets, wherein the first heads included in the plurality of recording heads are arranged in parallel with a horizontal direction orthogonal to the transport direction. A) ejecting the first ink from a plurality of nozzles, a) storing a correspondence relationship between the ejection amount of the first ink and the expansion / contraction amount of the recording medium in the transport direction, and b) image data A step of calculating a discharge amount of the first ink for each recording region in charge of the nozzle of the first head based on the included first ink component image; and c) the step calculated in step b). Discharge amount and before Based on the correspondence, for each of the recording area, based on said determining a stretching amount in the conveying direction, d) the discharge amount calculated in said step b) of the recording medium by the first ink Te, wherein the first the recording medium from the head, said a step of discharging droplets of the first ink, e) the expansion amount determined in the step c), the second ink component included in the image data Discharging a second ink droplet from the second head disposed on the downstream side in the transport direction from the first head to the recording medium based on the image.

According to an eighth aspect of the present invention, in the image recording method of the seventh aspect , the recording medium is moved with respect to the plurality of recording heads fixedly arranged.

According to a ninth aspect of the present invention, in the image recording method of the seventh or eighth aspect , the ink droplets are ejected from the plurality of recording heads while applying a tension in the transport direction to the recording medium.

Tenth aspect of the present invention, in any one of the image recording method of the seventh invention to the ninth invention, further comprising the step of deforming the second ink component image according to the amount of expansion or contraction, in the step e) Then, based on the deformed second ink component image, the second ink droplet is ejected from the second head.

An eleventh invention of the present application further includes a step of obtaining a correction time corresponding to the expansion / contraction amount in any of the image recording methods from the seventh invention to the ninth invention, and in the step e ), the second head The ejection timing of the droplets of the second ink from is changed based on the correction time.

According to a twelfth aspect of the present invention, in the image recording method according to any one of the seventh to eleventh aspects, in the step e), the second ink ejected from the second head according to the expansion / contraction amount . The number of droplets discharged in the transport direction is changed.

According to the first to twelfth inventions of the present application, the ejection operation of the second head can be controlled in accordance with the amount of expansion and contraction of the recording medium in the transport direction by the first ink. For this reason, it is possible to suppress the positional relationship between the first ink component image and the second ink component image recorded on the recording medium from deviating from an ideal positional relationship at least in the transport direction.

In particular, according to the third or ninth invention of the present application, image quality can be improved by suppressing slack and wrinkles of the recording medium. Further, when a tension in the transport direction is applied, the first ink tends to stretch in the transport direction of the recording medium. However, according to the present invention, a shift in the recording position of the second ink due to the stretch can be suppressed.

In particular, according to the sixth invention or the twelfth invention of the present application, the number of ejections of the second ink from the second head can be set to an optimum ejection number according to the expansion / contraction amount. Thereby, for example, it is possible to prevent the second ink from partially missing in a region where the second ink should continue in the transport direction.

1 is a diagram illustrating a configuration of an image recording apparatus according to a first embodiment. It is the figure which showed the example of the correspondence data concerning 1st Embodiment. 4 is a flowchart illustrating a flow of printing processing according to the first embodiment. It is the figure which showed notionally the mode of the process which decomposes | disassembles an image. It is the figure which showed notionally the mode of the process which determines the amount of expected growth. It is the figure which showed notably the mode of the process which deform | transforms an image. It is a top view of the printing paper immediately after discharge of Y color ink. FIG. 6 is a top view of a printing sheet immediately before ejection of M color ink. It is a top view of the printing paper after ejection of M color ink. It is a top view of the printing paper after a drying process. 10 is a flowchart illustrating a flow of a printing process according to the second embodiment. It is the figure which showed notionally the mode of the process which calculates correction | amendment time. FIG. 6 is a diagram illustrating a relationship between ink ejection timing and a recorded image. It is an enlarged view of the droplet discharged on the upper surface of the printing paper.

  Embodiments of the present invention will be described below with reference to the drawings.

<1. First Embodiment>
<1-1. Configuration of Image Recording Device>
FIG. 1 is a diagram showing a configuration of an image recording apparatus 1 according to the first embodiment of the present invention. This image recording apparatus 1 discharges ink from a plurality of recording heads 21 to 24 to the printing paper 9 while transporting the printing paper 9 which is a long sheet-like recording medium, whereby the printing paper 9 is colored. An inkjet printing apparatus for recording an image. As shown in FIG. 1, the image recording apparatus 1 includes a transport mechanism 10, an image recording unit 20, a drying processing unit 30, and a control unit 40.

  The transport mechanism 10 is a mechanism for transporting the printing paper 9 in the longitudinal direction. The transport mechanism 10 according to the present embodiment includes an unwinding unit 11, a plurality of rollers 12, and a winding unit 13. The printing paper 9 is fed out from the unwinding unit 11 and conveyed along a conveyance path constituted by a 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, the printed printing paper 9 is collected to the winding unit 13.

  As shown in FIG. 1, the printing paper 9 moves along a conveyance direction parallel to the arrangement direction of the recording heads 21 to 24 below the image recording unit 20. At this time, the recording surface of the printing paper 9 is directed upward (the recording heads 21 to 24 side). Further, when the printing paper 9 comes into contact with the plurality of rollers 12, tension in the transport direction is applied to the printing paper 9. Thereby, slack and wrinkles of the printing paper 9 during conveyance are suppressed. That is, in this embodiment, the plurality of rollers 12 are part of the transport mechanism 10 and also function as a tension applying unit that applies tension in the transport direction to the printing paper 9.

  The image recording unit 20 is a mechanism that ejects ink droplets onto the printing paper 9 conveyed by the conveyance mechanism 10. The image recording unit 20 of this embodiment includes a Y color head 21, an M color head 22, a C color head 23, and a K color head 24. These recording heads 21 to 24 have a plurality of nozzles arranged in parallel with the width direction of the printing paper 9 (horizontal direction orthogonal to the transport direction). Each of the recording heads 21 to 24 has a color component of Y (Yellow), M (Magenta), C (Cyan), and K (Black) as color components of the color image from a plurality of nozzles toward the upper surface of the printing paper 9. Each ink droplet is ejected. Thereby, a color image is recorded on the upper surface of the printing paper 9.

  That is, the Y color head 21 ejects Y color ink droplets onto the upper surface of the printing paper 9. The M color head 22 ejects droplets of M color ink onto the upper surface of the printing paper 9 on the downstream side in the transport direction from the Y color head 21. The C color head 23 ejects droplets of C color ink onto the upper surface of the printing paper 9 on the downstream side in the transport direction from the M color head 22. The K-color head 24 ejects droplets of K-color ink onto the upper surface of the printing paper 9 on the downstream side in the transport direction from the C-color head 23.

  The drying processing unit 30 is a mechanism for drying the ink ejected on the printing paper 9. The drying processing unit 30 is disposed downstream of the K color head 24 in the transport direction. For example, the drying processing unit 30 blows a heated gas on the printing paper 9 to vaporize the solvent in the ink attached to the printing paper 9, thereby drying the ink. However, the drying processing unit 30 may dry the ink by other methods such as light irradiation.

  The control unit 40 is means for controlling the operation of each unit in the image recording apparatus 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. As indicated by broken lines in FIG. 1, the control unit 40 is electrically connected to the transport mechanism 10, the four recording heads 21 to 24, and the drying processing unit 30 described above. The control unit 40 temporarily reads the computer program P stored in the storage unit 43 into the memory 42, and the arithmetic processing unit 41 performs arithmetic processing based on the computer program P, thereby controlling the operation of each unit described above. To do. Thereby, the printing process in the image recording apparatus 1 proceeds.

  The control unit 40 is electrically connected to the server 2 installed outside the image recording apparatus 1. The server 2 stores image data D to be printed. During the printing process, the printing paper 9 is conveyed by the conveyance mechanism 10 and ink of each color is ejected from each recording head 21 to 24 based on the designated image data D. As a result, an image corresponding to the image data D is recorded on the upper surface of the printing paper 9.

  Further, the image recording apparatus 1 of the present embodiment stores correspondence data C in the storage unit 43. FIG. 2 is a diagram showing an example of the correspondence data C. As shown in FIG. 2, the correspondence data C is data that defines the correspondence between the ink ejection amount and the extension amount of the printing paper 9 in the transport direction by the ink. The correspondence relationship between the ink ejection amount and the elongation amount in the transport direction of the printing paper 9 is obtained by measuring in advance through experiments or the like. The correspondence relationship data C is stored in the storage unit 43 in advance by the user of the image recording apparatus 1 before performing the printing process, for example.

<1-2. Printing process in image recording apparatus>
Next, the printing process in the image recording apparatus 1 described above will be described. FIG. 3 is a flowchart showing the flow of printing processing in the image recording apparatus 1. 4 to 6 are diagrams conceptually showing the state of image processing executed in the control unit 40. FIG. 7 to 10 are top views of the printing paper 9 at each stage of the printing process.

  Hereinafter, as an example, a case where an image of a “T” character composed of a composite color of Y color and M color is printed will be described. Therefore, in the following example, the Y-color head 21 is a first head that discharges a droplet of Y-color ink as the first ink. Further, the M color head 22 becomes a second head that ejects droplets of M color ink as the second ink.

  When printing processing is performed in the image recording apparatus 1, first, the control unit 40 separates the image in the image data D read from the server 2 for each color component (step S11). In the present embodiment, since the image of the “T” character in the image data D is composed of a composite color of Y and M, the image in the image data D is Y color as shown in FIG. The ink component image Iy and the M color ink component image Im are separated.

  Next, the control unit 40 reads the correspondence data C from the storage unit 43. Then, as shown in FIG. 5, based on the correspondence data C and the Y color ink component image Iy, the expected elongation amount E of the printing paper 9 with the Y color ink is determined (step S12). Here, first, the ejection amount of Y color ink from the Y color head 21 is calculated based on the Y color ink component image Iy. The discharge amount of Y color ink is calculated for each recording region (region of 1 pixel width divided in the width direction) which each nozzle of the recording head takes charge. Then, with reference to the correspondence data C, the expected elongation amount E of the printing paper 9 corresponding to the discharge amount of the Y color ink is obtained for each recording area described above.

  Subsequently, the control unit 40 deforms the M color ink component image Im in accordance with the calculated expected elongation amount E (step S13). Here, the M color ink component image Im is enlarged in the transport direction in accordance with the expected elongation amount E for each of the recording areas described above. Therefore, as shown in FIG. 2, when the ink ejection amount and the elongation amount of the printing paper 9 have a positive correlation, the larger the Y-color ink ejection amount, the larger the enlargement rate in the transport direction. As a result, an M color ink component image Im enlarged in the width direction is obtained as shown in FIG.

  In the example of FIG. 6, the M color ink component image Im is enlarged equally on the left and right with reference to the center in the transport direction, but the reference position for the enlargement does not necessarily have to be in the center in the transport direction. For example, the image may be enlarged using the edge of the M color ink component image Im on the most downstream side in the transport direction as a reference. The enlargement reference position may be set to a position close to the actual situation in consideration of the expansion / contraction characteristics of the printing paper 9, the tension applied to the printing paper 9, and the like.

  When the above image processing is completed, the image recording apparatus 1 first discharges Y color ink droplets from the Y color head 21 onto the upper surface of the printing paper 9 while conveying the printing paper 9 (step S14). That is, the control unit 40 causes the Y-color head 21 to eject Y-color ink droplets based on the undeformed Y-color ink component image Iy.

  Immediately after the Y color ink droplets are ejected, as shown in FIG. 7, the Y color ink component image Iy is recorded on the upper surface of the printing paper 9 almost according to the instructed dimensions. However, when the Y color ink permeates the printing paper 9, the printing paper 9 is stretched, and the Y color ink component image Iy is deformed as shown in FIG. In particular, in the present embodiment, tension is applied to the printing paper 9 in the transport direction. For this reason, the printing paper 9 and the Y-color ink component image Iy recorded on the printing paper 9 mainly extend in the transport direction.

  Subsequently, the image recording apparatus 1 ejects M color ink droplets from the M color head 22 onto the upper surface of the print paper 9 while transporting the print paper 9 (step S15). Here, if the M color head 22 ejects droplets of M color ink based on the M color ink component image Im before deformation, the printing paper 9 is affected by the expansion of the printing paper 9 described above. The positional relationship between the Y-color ink component image Iy and the M-color ink component image Im is shifted from the ideal positional relationship.

  However, in step S15, the control unit 40 causes the M color head 22 to eject M color ink droplets based on the deformed M color ink component image Im. Thereby, the M color ink component image Im is recorded on the upper surface of the printing paper 9. As described above, the deformed M color ink component image Im has a size reflecting the expected amount of elongation E of the printing paper 9 with the Y color ink. Therefore, after the ejection of the M color ink, as shown in FIG. 9, the Y color ink component image Iy and the M color ink component image Im overlap on the upper surface of the printing paper 9 with almost no deviation.

  Thereafter, the image recording apparatus 1 further conveys the printing paper 9 to the downstream side in the conveyance direction, and in the drying processing unit 30, the ink (Y color ink and M color ink in this embodiment) attached to the printing paper 9 is used. Dry (step S16). When the ink is dried, the elongation in the transport direction of the printing paper 9 returns to a dimension close to the original state. As a result, as shown in FIG. 10, an image of the “T” character almost as specified by the image data D is obtained.

  Thus, in the present embodiment, after the Y color ink component image Iy is recorded on the printing paper 9, the M color ink component image Im enlarged according to the expected elongation amount E of the printing paper 9 by the Y color ink is obtained. Record on printing paper 9. For this reason, it is possible to suppress the positional relationship between the Y color ink component image Iy and the M color ink component image Im recorded on the printing paper 9 from deviating from an ideal positional relationship at least in the transport direction.

<When recording an image composed of 1-3 colors or more>
In the above example, the case where an image composed of only two colors of Y and M is recorded has been described. However, when an image composed of three or more colors is recorded, the third and subsequent color components are recorded. Alternatively, the ink may be ejected by deforming the image. Specifically, the nth ink may be ejected from the nth head as follows, where n is an arbitrary integer of 2 or more.

  First, based on the total discharge amount from the first ink to the (n−1) th ink and the correspondence data C, an expected elongation amount E in the transport direction of the printing paper 9 is obtained. Next, the nth ink component image is enlarged in the transport direction in accordance with the expected elongation amount E. Then, the nth ink is ejected from the nth head onto the upper surface of the printing paper 9 based on the enlarged nth ink component image.

  In this way, even when an image composed of many color components is printed, the mutual positional relationship among the plurality of color component images recorded on the printing paper 9 is an ideal position at least in the transport direction. You can get closer to the relationship. Therefore, the image quality of the printed material can be further improved.

<2. Second Embodiment>
Subsequently, a second embodiment of the present invention will be described. Also in the second embodiment, the configuration itself of the image recording apparatus 1 is the same as that of the first embodiment described above. In this embodiment, the positional relationship between the images of the respective colors recorded on the printing paper 9 is corrected by shifting the ink ejection timing according to the elongation of the printing paper 9 without deforming the image as data. .

  FIG. 11 is a flowchart showing the flow of printing processing according to the second embodiment. Hereinafter, as in the first embodiment, an example of printing an image of a “T” character composed of a composite color of Y color and M color will be described.

  The processes in steps S21 to S22 in FIG. 11 are the same as steps S11 to S12 in the first embodiment. That is, first, the control unit 40 decomposes the image in the image data D read from the server 2 for each color component (step S21). Next, the control unit 40 reads the correspondence data C from the storage unit 43. Then, based on the correspondence relationship data C and the Y color ink component image Iy, the expected elongation amount E of the printing paper 9 by the Y color ink is determined (step S22).

  Subsequently, as shown in FIG. 12, the control unit 40 calculates the correction time Δt based on the expected elongation amount E and the transport speed S of the printing paper 9 by the transport mechanism 10 (step S23). Here, the movement time of the printing paper 9 corresponding to the expected elongation amount E is obtained as the correction time Δt. The correction time Δt is calculated for each recording region (region of 1 pixel width divided in the width direction) assigned to each nozzle of the recording head. The calculation formula for calculating the correction time Δt may be, for example, Δt = E / S.

  When the above processing is completed, the image recording apparatus 1 first discharges Y color ink droplets from the Y color head 21 onto the upper surface of the printing paper 9 while transporting the printing paper 9 (step S24). That is, the control unit 40 causes the Y-color head 21 to eject Y-color ink droplets based on the Y-color ink component image Iy.

  Subsequently, the image recording apparatus 1 ejects M color ink droplets from the M color head 22 onto the upper surface of the printing paper 9 while transporting the printing paper 9 (step S25). At this time, the image recording apparatus 1 changes the ejection timing of the M color ink from the M color head 22 based on the correction time Δt described above.

  FIG. 13 is a diagram showing the relationship between the image recorded on the upper surface of the printing paper 9 and the discharge timing of the Y color ink in step S25. In FIG. 13, the original ejection timing based on the M color ink component image Im in the image data D is indicated by a broken line. As shown in FIG. 13, in step S25, the time zone during which the droplets of M-color ink are ejected is expanded by, for example, Δt / 2 before and after. Then, the M color ink droplets are uniformly ejected in the enlarged time zone. As a result, the Y-color ink component image Iy and the M-color ink component image Im can be superimposed on the upper surface of the printing paper 9 with almost no deviation.

  Note that the method of expanding the time zone during which the M color ink is ejected is not necessarily as shown in FIG. How to apply the correction time Δt to the original ejection timing may be set for each printing process in consideration of the expansion / contraction characteristics of the printing paper 9 and the tension applied to the printing paper 9. .

  Thereafter, the image recording apparatus 1 further conveys the printing paper 9 to the downstream side in the conveyance direction, and in the drying processing unit 30, the ink (Y color ink and M color ink in this embodiment) attached to the printing paper 9 is used. Dry (step S26). When the ink is dried, the elongation in the transport direction of the printing paper 9 returns to a dimension close to the original state. As a result, an image of the “T” character almost as specified by the image data D is obtained.

  As described above, in this embodiment, after the Y color ink component image Iy is recorded on the printing paper 9, when the droplets of the M color ink are ejected, the expected elongation amount E of the printing paper 9 by the Y color ink is supported. Based on the correction time Δt to be changed, the ejection timing of the M color ink is changed. Thereby, it is possible to suppress the positional relationship between the Y color ink component image Iy and the M color ink component image Im recorded on the printing paper 9 from deviating from an ideal positional relationship at least in the transport direction.

  As described above, when the time zone during which the M color ink is ejected is expanded, the ejection interval of the M color ink from the M color head is increased. For this reason, for example, as shown in FIG. 14 (a), the gap between the adjacent droplets Lm as shown in FIG. May occur. Such a gap may remain even after the elongation of the printing paper 9 is eliminated by drying. Considering this point, the image recording apparatus 1 may change the number of ejections of the M color ink droplets Lm in the transport direction in accordance with the correction time Δt. Then, the gap between the adjacent droplets Lm can be eliminated, and a plurality of droplets Lm can be densely arranged on the upper surface of the printing paper 9 as shown in FIG.

  When an image composed of three or more colors is recorded, the ink ejection timing may be changed for the third and subsequent color components. Specifically, the nth ink may be ejected from the nth head as follows, where n is an arbitrary integer of 2 or more.

  First, based on the total discharge amount from the first ink to the (n−1) th ink and the correspondence data C, an expected elongation amount E in the transport direction of the printing paper 9 is obtained. Next, the movement time of the printing paper 9 corresponding to the expected elongation amount E is obtained as the correction time Δt. Then, the nth ink is ejected from the nth head while changing the original ejection timing based on the nth ink component image based on the correction time Δt.

  In this way, even when an image composed of many color components is printed, the mutual positional relationship among the plurality of color component images recorded on the printing paper 9 is an ideal position at least in the transport direction. You can get closer to the relationship. Therefore, the image quality of the printed material can be further improved.

<3. Modification>
As mentioned above, although main embodiment of this invention was described, this invention is not limited to said embodiment.

  In each of the embodiments described above, the expected elongation amount E is obtained for each region of 1 pixel width divided in the width direction. However, the expected elongation amount E is calculated for each region of a plurality of pixel widths divided in the width direction. You may ask for it. Therefore, the deformation of the image and the change of the ejection timing may be performed for each region having a plurality of pixel widths.

  In the above embodiment, the case where the Y color ink component image Iy and the M color ink component image Im overlap has been described. However, in the present invention, the images to be recorded are the Y color ink component image Iy and the M color ink. The ink component image Im may be an image recorded at a different position. Even in such a case, by performing the printing process described above, the positional relationship between the Y color ink component image Iy and the M color ink component image Im is prevented from deviating from an ideal positional relationship at least in the transport direction. it can.

  Further, in the above embodiment, the expected elongation amount E of the printing paper 9 is obtained based on the correspondence data C stored in the storage unit 43, but the elongation amount of the printing paper 9 is measured by the image recording apparatus 1. An additional sensor may be added, and the deformation amount of the image and the correction time Δt may be obtained based on the amount of elongation actually measured by the sensor.

  The present invention can also be applied to cases where the printing paper 9 shrinks when ink is ejected. When shrinkage occurs in the printing paper 9, an expected shrinkage amount in the transport direction of the printing paper 9 is obtained in step S12 or step S22, and in step S13 or step S23, the image is deformed according to the expected shrinkage amount. Alternatively, the correction time Δt may be calculated. That is, the “expansion / contraction amount” in the present invention only needs to include information on at least one of the extension amount and the contraction amount.

  In the above embodiment, the four recording heads 21 to 24 are provided in the image recording apparatus 1. However, the number of recording heads in the image recording apparatus 1 may be two to three, or may be five or more. For example, in addition to Y, M, C, and K colors, a head that discharges special color inks may be provided. The image recording apparatus of the present invention includes a first head that discharges a droplet of a first ink toward a recording medium, and a second ink having a color different from that of the first ink on the downstream side in the transport direction from the first head. And a second head that discharges the liquid droplets toward the recording medium.

  In the above embodiment, the printing paper 9 is moved in the transport direction with respect to the plurality of recording heads 21 to 24 that are fixedly arranged. However, the position of the printing paper 9 may be fixed, and the plurality of recording heads 21 to 24 may be moved with respect to the printing paper 9. That is, the transport mechanism of the present invention may be any mechanism that relatively moves the plurality of recording heads and the recording medium.

  In the above embodiment, the printing paper 9 on a long sheet is conveyed using a plurality of rollers. However, the image recording apparatus of the present invention may record an image while placing and transporting a sheet-like printing paper cut into small pieces on a movable table.

  The image recording apparatus 1 records an image on the printing paper 9 as a recording medium. However, the image recording apparatus of the present invention may record 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 Image recording apparatus 2 Server 9 Printing paper 10 Conveyance mechanism 11 Unwinding part 12 Roller 13 Winding part 20 Image recording part 21 Y color head 22 M color head 23 C color head 24 K color head 30 Drying process part 40 Control part 43 Storage unit C Corresponding relationship data D Image data E Expected elongation Iy Y color ink component image Im M color ink component image Lm Droplet P Computer program S Transport speed Δt Correction time

Claims (12)

An image recording apparatus for recording an image on a sheet-like recording medium,
A plurality of recording heads;
A transport mechanism that relatively moves the plurality of recording heads and the recording medium along a transport direction parallel to an arrangement direction of the plurality of recording heads;
A control unit that controls the plurality of recording heads and the transport mechanism based on image data;
With
The plurality of recording heads include:
A first head having a plurality of nozzles arranged in parallel with a horizontal direction orthogonal to the transport direction, and ejecting droplets of a first ink from the nozzles toward the recording medium;
A second head for ejecting droplets of a second ink having a color different from that of the first ink toward the recording medium on the downstream side in the transport direction from the first head;
Including
The controller is
A storage unit that stores a correspondence relationship between the ejection amount of the first ink and the expansion / contraction amount of the recording medium in the transport direction;
Based on the first ink component image included in the image data, the first head causes the first ink droplets to be ejected, and based on the first ink component image, the nozzles of the first head The first ink discharge amount is calculated for each recording region in charge, and the first ink discharge amount is calculated for each recording region based on the calculated first ink discharge amount and the correspondence read from the storage unit. An amount of expansion / contraction of the recording medium in the transport direction by the first ink is determined, and the second head is configured to perform the second ink component image included in the image data based on the determined expansion / contraction amount and the second ink component image. An image recording apparatus that ejects two ink droplets. The image recording apparatus according to claim 1,
The image recording apparatus in which the transport mechanism moves the recording medium with respect to the plurality of recording heads arranged in a fixed manner. The image recording apparatus according to claim 1 or 2,
An image recording apparatus further comprising a tension applying unit that applies tension in the transport direction to the recording medium. In the image recording device according to any one of claims 1 to 3,
The controller is
Deforming the second ink component image according to the amount of expansion and contraction;
An image recording apparatus that causes the second head to eject droplets of the second ink based on the deformed second ink component image. In the image recording device according to any one of claims 1 to 3,
The controller is
An image recording apparatus that changes a discharge timing of the second ink droplet from the second head based on a correction time corresponding to the expansion / contraction amount. In the image recording device according to any one of claims 1 to 5,
The controller is
An image recording apparatus that changes the number of ejections of the droplets of the second ink ejected from the second head in the transport direction in accordance with the expansion / contraction amount. By ejecting ink droplets from the plurality of recording heads while relatively moving the plurality of recording heads and the sheet-like recording medium along a conveyance direction parallel to the arrangement direction of the plurality of recording heads. An image recording method for recording an image on the recording medium,
The first head included in the plurality of recording heads discharges the first ink from a plurality of nozzles arranged in parallel with a horizontal direction orthogonal to the transport direction,
a) storing a correspondence relationship between the ejection amount of the first ink and the expansion / contraction amount of the recording medium in the transport direction;
b) calculating a discharge amount of the first ink for each recording region handled by the nozzles of the first head based on a first ink component image included in the image data;
c) determining an expansion / contraction amount of the recording medium in the transport direction by the first ink for each recording region based on the ejection amount calculated in the step b) and the correspondence relationship; ,
d) ejecting droplets of the first ink from the first head to the recording medium based on the ejection amount calculated in the step b);
e) Based on the expansion / contraction amount determined in the step c) and the second ink component image included in the image data, the second head arranged on the downstream side in the transport direction from the first head Discharging a second ink droplet onto a recording medium;
An image recording method comprising: The image recording method according to claim 7,
An image recording method for moving the recording medium with respect to the plurality of recording heads fixedly arranged. In the image recording method according to claim 7 or 8,
An image recording method for ejecting ink droplets from the plurality of recording heads while applying a tension in the transport direction to the recording medium. In the image recording method according to any one of claims 7 to 9,
Further comprising the step of deforming the second ink component image according to the amount of expansion and contraction,
In the step e), an image recording method in which droplets of the second ink are ejected from the second head based on the deformed second ink component image. In the image recording method according to any one of claims 7 to 9,
A step of obtaining a correction time corresponding to the amount of expansion and contraction;
In the step e), an image recording method in which the discharge timing of the droplets of the second ink from the second head is changed based on the correction time. The image recording method according to any one of claims 7 to 11,
In the step e), an image recording method of changing the number of ejections of the second ink droplets ejected from the second head in the transport direction in accordance with the expansion / contraction amount.

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