JP5615380B2 - Inkjet printer - Google Patents

Description

  The present invention relates to an ink jet printer that discharges ink droplets from an ink jet head and performs printing on a medium.

  Conventionally, textile printing has been performed on fabric media such as woven fabrics and knitted fabrics using an inkjet printer. In textile printing using this ink jet printer, as in normal printing, the ink jet head is scanned in the scanning direction to discharge ink droplets from the ink jet head, and the cloth medium is transported in a direction orthogonal to the scanning direction for each scan. It is transported to. The ink jet printer controls the ink droplet ejection timing and the conveyance amount in the conveyance direction of the cloth medium so that the ink droplets that land on the cloth medium have an interval corresponding to the set resolution. Yes.

Japanese Patent Laid-Open No. 02-293174 JP 2002-326344 A

  By the way, cloth media for textile printing are formed with textured or stitched holes (hereinafter, the textured or stitched holes of the fabric media are simply referred to as “fabric media holes”). Part of the ink droplets ejected from the ink drops into the hole of the cloth medium without landing on the cloth medium.

  However, in the conventional ink jet printer, the transport amount in the transport direction of the cloth media is controlled only in accordance with the set resolution. Therefore, periodicity is generated at the positions where the ink droplets fall into the holes of the cloth media, and moire is generated. Stripes are generated.

  Therefore, Patent Documents 1 and 2 are disclosed as techniques for suppressing the generation of moire fringes in printing using an inkjet printer.

  In Patent Document 1, in the case of performing dot overprinting, in order to suppress the occurrence of moire fringes due to overprinting of dots more than necessary, the media feed amount is set in accordance with the thickness of the media. Is described.

  However, since the technique described in Patent Document 1 is merely a technique for adjusting the number of overlapping dots, it is not possible to suppress moire fringes that occur during textile printing on cloth media.

  Further, in Patent Document 2, when performing textile printing on a cloth medium, the resolution is changed to an optimum resolution for each cloth medium in order to suppress the occurrence of moire fringes. It is described that the color change of printing can be prevented while changing moire fringes by suppressing the moire pattern.

  However, the technique described in Patent Document 2 has a periodicity in the interval between the ink droplets that fall into the holes in the cloth media because the transport amount of the cloth media becomes constant after the resolution is changed to the optimum for each cloth medium. However, the problem that moire fringes are generated due to the occurrence of such a problem has not been sufficiently solved. Moreover, the technique described in Patent Document 2 newly creates a look-up table (LUT) that is used when converting image data into drive data for an inkjet head in order to prevent a change in the color of printing due to a change in resolution. ing. That is, in Patent Document 2, first, the gradation data of each color is adjusted to correct the gradation data (step S103), and then an LUT in which color interpolation is performed based on the corrected gradation data is created. (Step S104) Next, as the input data used for the error diffusion method, different data depending on the combination of color density and color is input to the personal computer (Step S105), and then the desired image is changed again. Printing is performed on the fabric by the error diffusion method based on the LUT and the changed input data (step S106). As described above, in the technique described in Patent Document 2, two operations of changing the resolution and preventing the color change of the printing are generated in order to suppress the occurrence of moire. is there.

  Therefore, an object of the present invention is to provide an ink jet printer that can suppress the generation of moire fringes without deteriorating workability when performing textile printing.

  The ink jet printer according to the present invention scans an ink jet head on which nozzles for ejecting ink droplets are mounted in the scanning direction, and relatively moves the ink jet head and the medium in a transport direction orthogonal to the scanning direction, An ink jet printer that performs printing on a medium, wherein the relative movement amount of the ink jet head and the medium in the transport direction is changed for each scanning within a range in which the resolution does not change.

  According to the ink jet printer of the present invention, since the relative movement amount of the ink jet head and the medium in the transport direction is changed for each scan, when performing textile printing on the cloth medium, the ink droplets are generated on the cloth medium. Since the intervals falling into the holes become irregular and the periodicity is lost, the generation of moire fringes can be suppressed. In addition, since the amount of movement is varied within a range in which the resolution does not change, the problem of color change associated with the change in resolution does not occur, so the occurrence of moire fringes can be suppressed without deteriorating workability.

  The relative movement amount of the inkjet head and the medium in the transport direction is preferably varied within a range where white stripes or black stripes are not generated between the print lines printed in each scan. In this way, by setting the fluctuation range of the movement amount within a range in which white stripes or black stripes are not generated between the print lines, it is possible to prevent the image quality from deteriorating.

  In addition, it is preferable that the relative movement amount of the inkjet head and the medium in the transport direction is different for each scan. In this way, by varying the amount of movement for each scan, the interval at which the ink droplets fall into the holes in the cloth media can be appropriately made non-uniform.

  In this case, it is preferable that the relative movement amount of the inkjet head and the medium in the transport direction is changed stepwise in one direction. In this way, by changing the movement amount in one direction in steps, the positional deviation of the ink droplets that land on the cloth medium can be made inconspicuous, so that it is possible to suppress a decrease in print image quality.

  Also, after changing the relative movement amount of the inkjet head and media in the transport direction stepwise in one direction, the relative movement amount of the inkjet head and media in the transport direction stepwise in the other direction. It is preferable to change to In this way, after the movement amount is changed stepwise in one direction, the movement amount is changed stepwise in the other direction, thereby making the positional deviation of the ink droplets that land on the cloth media more inconspicuous. Therefore, it is possible to further suppress a decrease in print image quality.

  And it is preferable to further have a fluctuation amount setting means for setting a fluctuation amount that fluctuates the relative movement amount of the inkjet head and the medium in the transport direction. In this way, by allowing the movement amount to be set by the variation amount setting means, it is possible to appropriately suppress the occurrence of moire fringes according to, for example, the type of cloth media and the inclination state of the cloth media.

  Also, in order to change the relative movement amount of the inkjet head and the medium in the conveyance direction for each scan within the range where the resolution does not change, the relative movement amount of the inkjet head and the medium in the conveyance direction is changed. It is preferable to further have switching means for manual switching. By having such a switching means, finer adjustment based on the operator's vision becomes possible.

  In the media transport method according to the present invention, an inkjet head on which nozzles for ejecting ink droplets are mounted is scanned in the scanning direction, and the inkjet head and the medium are relatively moved in the transport direction orthogonal to the scanning direction. A medium transport method for an ink jet printer that performs printing on a medium, characterized in that the relative movement amount of the ink jet head and the medium in the transport direction is changed within a range in which the resolution does not change for each scan. To do.

  According to the media transport method of the present invention, the ink droplets are transferred to the fabric media when performing printing printing on the fabric media in order to change the relative movement amount of the inkjet head and the media in the transport direction for each scan. Since the intervals falling into the holes become irregular and the periodicity is lost, the generation of moire fringes can be suppressed. In addition, since the amount of movement is varied within a range in which the resolution does not change, the problem of color change associated with the change in resolution does not occur, so the occurrence of moire fringes can be suppressed without deteriorating workability.

  The medium transport program according to the present invention scans an ink jet head on which nozzles for ejecting ink droplets are mounted in the scanning direction, and relatively moves the ink jet head and the medium in a transport direction orthogonal to the scanning direction. A medium transport program for causing an ink jet printer to perform printing on a medium to be executed, and for each scan, the relative movement amount of the ink jet head and the medium in the transport direction is changed within a range in which the resolution does not change. It is characterized by that.

  According to the media transport program of the present invention, the ink droplets are transferred to the cloth media when performing printing printing on the cloth media in order to change the relative movement amount of the inkjet head and the media in the transport direction for each scan. Since the intervals falling into the holes become irregular and the periodicity is lost, the generation of moire fringes can be suppressed. In addition, since the amount of movement is varied within a range in which the resolution does not change, the problem of color change associated with the change in resolution does not occur, so the occurrence of moire fringes can be suppressed without deteriorating workability.

  According to the present invention, it is possible to suppress the occurrence of moire fringes without deteriorating workability when performing textile printing.

1 is a schematic configuration diagram of an inkjet printer according to an embodiment. It is a block diagram which shows the function structure of a control part. It is a block diagram which shows the function structure of a media conveyance control part. It is a figure which shows the relationship between a feed stripe and deviation | shift amount. 4A and 4B are diagrams illustrating landing images of ink droplets. FIG. 5A illustrates a case where the cloth medium is transported by a reference transport amount, and FIG. 5B illustrates a case where the cloth medium is transported by a control transport amount. FIG. 10 is a diagram illustrating a landing state of ink liquid on the cloth medium M when transport control is performed with a reference transport amount. FIG. 6 is a diagram illustrating a landing state of ink droplets on a cloth medium when transport control is performed with a controlled transport amount.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of an inkjet printer according to the invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

  FIG. 1 is a schematic configuration diagram of an ink jet printer according to the present embodiment. As shown in FIG. 1, an ink jet printer 1 is a printer that performs textile printing on a cloth medium M such as a woven fabric or a knitted fabric by an ink jet method, and includes a head unit 2 held movably in a scanning direction S, and a head unit 2 Mounted on the inkjet head 3 for discharging ink droplets, a drive mechanism 4 for moving (scanning) the head unit 2 in the scanning direction S, and conveyance for conveying the cloth medium M in the conveyance direction F orthogonal to the scanning direction S. A mechanism 5 and a control unit 6 that performs overall control of the inkjet printer 1 are provided. The scanning direction S is also called a scanning direction or a main scanning direction, and the transport direction F is also called a feed direction or a sub-scanning direction.

  The inkjet head 3 is formed with a plurality of nozzles 3a for ejecting ink droplets. These nozzles 3 a form a nozzle row having a predetermined length along the transport direction F. For this reason, when the head unit 2 scans, ink droplets are ejected from the respective nozzles 3a, whereby a print line having the same width as the nozzle row can be formed on the cloth medium M.

  The drive mechanism 4 may have any configuration as long as the head unit 2 can be moved in the scanning direction S. For example, the drive mechanism 4 can be configured by an endless belt (not shown) connected to the head unit 2 and extending in the scanning direction S, and a drive motor (not shown) that rotationally drives the endless belt. By configuring the drive mechanism 4 as described above and controlling the rotational speed of the drive motor, the head unit 2 can be reciprocated in the scanning direction S at a predetermined speed.

  The transport mechanism 5 may have any configuration as long as the cloth medium M can be moved in the transport direction F. For example, the transport mechanism 5 can be configured by a plurality of transport rollers held rotatably in the transport direction and a drive motor (not shown) that rotationally drives the transport rollers. By configuring the transport mechanism 5 as described above and controlling the rotation amount of the drive motor, the cloth medium M can be transported in the transport direction F by a predetermined amount.

  The control unit 6 performs textile printing on the cloth medium M by comprehensively controlling the inkjet head 3, the drive mechanism 4, and the transport mechanism 5 based on print data transmitted from an external device such as a personal computer (not shown). It is. The control unit 6 is mainly configured by a computer including a CPU, a ROM, and a RAM, for example, and reads predetermined computer software on the CPU and RAM, and operates under the control of the CPU. Each function of the control unit 6 to be described later is realized.

  FIG. 2 is a block diagram illustrating a functional configuration of the control unit. As shown in FIG. 2, the control unit 6 functions as a head drive control unit 61, a discharge control unit 62, and a media transport control unit 63. Hereinafter, each function of the control unit 6 will be described in detail.

  The head drive control unit 61 is a part that reciprocates the head unit 2 in the scanning direction S by performing drive control of the drive mechanism 4 based on print data.

  The ejection control unit 62 is a part that ejects ink droplets from each nozzle 3 a formed in the inkjet head 3 by performing ejection control of the inkjet head 3 based on the print data.

  The media conveyance control unit 63 is a part that conveys the cloth media M in the conveyance direction F by performing drive control of the conveyance mechanism 5 based on the print data. The media transport control unit 63 then transports the cloth media M in the transport direction F by changing the transport amount of the cloth media M in the transport direction F within a range in which the resolution does not change, particularly for each scan.

  FIG. 3 is a block diagram illustrating a functional configuration of the media transport control unit. As illustrated in FIG. 3, the media conveyance control unit 63 includes a reference conveyance amount calculation unit 631, a fluctuation amount calculation unit 632, and a control execution unit 633.

  The reference carry amount calculation unit 631 is a part that calculates the reference carry amount of the cloth medium M according to the print resolution. The printing resolution is the density of dots (ink droplets) formed on the cloth medium M, and is usually represented by the number of dots per inch (dots par inch: dpi). The reference carry amount is a carry amount of the cloth medium M in which dots are formed at a set print resolution and the dot intervals are equal.

  The fluctuation amount calculation unit 632 is a part that calculates a deviation amount (fluctuation amount) that fluctuates the conveyance amount of the cloth medium M in the conveyance direction F for each scan within a range in which the print resolution does not change.

  This deviation amount is a value for changing the transport amount in the transport direction F of the cloth medium M for each scanning by adding to the reference transport amount calculated by the reference transport amount calculation unit 631. Any value may be used as long as the resolution does not change.

  For example, the amount of misalignment is preferably in a range where white stripes (white stripes) or black stripes (black stripes) are not generated between print lines printed in each scan. A feed stripe is a stripe in the scanning direction S generated when print lines to be printed in each scan overlap or separate from each other. When these print lines overlap by a certain amount, a black stripe feed stripe is generated and these print lines are printed. When the lines are separated by a certain amount, white stripes are generated. FIG. 4 is a diagram illustrating the relationship between the feed stripe and the amount of deviation. FIG. 4 shows a case where textile printing is performed with the number of passes being 8 and the resolution being 600 dpi × 600 dpi, and the amount of deviation is shown in units of 3 μm. For this reason, for example, when the deviation amount is +1, the deviation amount is 3 μm in the conveyance direction F, and when the deviation amount is −2, the deviation amount is −6 μm in the conveyance direction F. In the case shown in FIG. 4, white streaks occur when the amount of deviation is −4 or more, and black streaks occur when the amount of deviation is −12 or less. Within the range of 11, the amount of deviation is calculated. Since the relationship between the feed stripe and the amount of deviation changes depending on the type and resolution of the cloth medium M, the relationship between the feed stripe and the amount of deviation is examined in advance, and the amount of deviation is calculated based on the result of this investigation. It is preferable.

  Further, it is preferable that the amount of deviation is a different value for each scan and is changed stepwise. For example, the amount of deviation may be changed stepwise in one direction (for example, the positive direction) such as 0, +1, +2, 0, +1, +2, and the amount of deviation may be changed to 0, +1, +2, +1, As in 0, after changing stepwise in one direction (for example, positive direction), it may be changed stepwise in the other direction (for example, negative direction). In this case, the unit of the deviation amount can be set to 3 μm, for example, as in the case of FIG.

  The control execution unit 633 calculates a control conveyance amount obtained by adding the deviation amount for each scan calculated by the variation amount calculation unit 632 to the reference conveyance amount calculated by the reference conveyance amount calculation unit 631, and performs conveyance based on the control conveyance amount. This is a part that executes drive control of the mechanism 5. For example, consider the case where the transport mechanism 5 includes a plurality of transport rollers and a drive motor that rotationally drives the transport rollers as described above. In this case, the control execution unit 633 first transports the cloth media M by the control transport amount based on the relationship between the rotation amount (rotation number) of the drive motor and the transport amount of the cloth media M transported by the rotation of the transport roller. Therefore, the rotation amount of the drive motor necessary for this is calculated, and the rotation drive control of the drive motor is performed based on the calculation result.

  Note that the reference transport amount calculated by the reference transport amount calculation unit 631, the deviation amount calculated by the variation amount calculation unit 632, and the control transport amount calculated by the control execution unit 633 are each assumed to be the transport amount of the cloth medium M. However, for example, the control amount (rotation amount) of the drive motor of the transport mechanism 5 may be used.

  Here, with reference to FIG. 5, the landing image of the ink droplet when the cloth medium M is conveyed by the controlled conveyance amount will be described. FIG. 5 is a diagram showing an image of landing of ink droplets. FIG. 5A shows a case where the cloth medium is conveyed by the reference conveyance amount, and FIG. 5B shows a case where the cloth medium is conveyed by the control conveyance amount. If so, each is shown. In FIG. 5B, the shift amount of the first scan is 0, the shift amount of the second scan is +1, the shift amount of the third scan is +2, the shift amount of the fourth scan is +1, and the shift amount of the fifth scan. In this example, the amount is set to 0, the shift amount at the sixth scan is set to +1, and the carry amount of the cloth medium is changed for each scan.

  As shown in FIG. 5A, when the cloth medium M is transported in the transport direction F by the reference transport amount, ink droplets land at equal intervals with a set resolution. On the other hand, as shown in FIG. 5B, when the cloth medium M is transported in the transport direction F by the control transport amount, the resolution does not change, but the transport amount of the cloth medium M fluctuates for each scan. The landing positions of the droplets are not uniform in the transport direction F.

  Next, the conveyance control operation of the cloth medium M in the inkjet printer 1 will be described. The operation of the inkjet printer 1 described below is performed under the control of the control unit 6. That is, in the control unit 6, a processing unit (not shown) constituted by a CPU or the like follows a program recorded in a storage device such as a ROM, a head drive control unit 61, a discharge control unit 62, a media transport control unit 63, etc. The following processing is performed by centrally controlling each function. Therefore, the program recorded in the storage device is a program that causes the inkjet printer 1 to perform these functions.

  First, the control unit 6 performs drive control of the drive mechanism 4 to reciprocate the head unit 2 in the scanning direction S, and performs ejection control of the inkjet head 3 to eject ink droplets from each nozzle 3a. As a result, one line of printing is performed on the cloth medium M.

  Next, the control unit 6 performs drive control of the transport mechanism 5 based on the control transport amount obtained by adding the deviation amount to the reference transport amount. As a result, the cloth medium M is transported in the transport direction F by the control transport amount. The control unit 6 calculates a reference transport amount, calculates a deviation amount, and calculates a control transport amount prior to driving control of the transport mechanism 5, and the control unit 6 acquires print data. Any timing may be used as long as the drive control of the drive mechanism 4 is executed.

  Here, with reference to FIG. 6 and FIG. 7, the landing state of the ink droplet on the cloth medium M will be described. FIG. 6 is a diagram showing a landing state of the ink liquid on the cloth medium M when the conveyance control is performed with the reference conveyance amount, and FIG. 7 is an ink droplet on the cloth medium when the conveyance control is performed with the control conveyance amount. It is the figure which showed the landing state of.

  As shown in FIG. 6, when the conveyance control is performed with the reference conveyance amount, the conveyance amount of the cloth medium M for each scan becomes constant while the holes of the cloth medium M are equally spaced. Then, periodicity occurs at the position where the ink droplet falls in the hole of the cloth medium M in the transport direction F. For this reason, moire fringes are generated on the fabric medium M that has been printed and printed.

  On the other hand, as shown in FIG. 7, when the conveyance control is performed with the controlled conveyance amount, the conveyance amount of the cloth medium M for each scanning changes while the holes of the cloth medium M are equally spaced. Then, the periodicity is lost at the position where the ink droplet falls in the hole of the cloth medium M in the transport direction F. For this reason, the moire fringes generated in the fabric medium M printed and printed are greatly suppressed.

  As described above, according to the inkjet printer 1 according to the present embodiment, since the transport amount of the cloth medium M in the transport direction F is changed for each scan, when performing textile printing on the cloth medium M, ink droplets are generated. Since the intervals falling into the holes of the cloth media M become irregular and the periodicity is lost, the generation of moire fringes can be suppressed. In addition, by changing the transport amount of the cloth media M within a range in which the resolution does not change, the problem of color change due to the change in resolution does not occur, so that the occurrence of moire fringes is suppressed without deteriorating workability. Can do.

  Then, by setting the fluctuation range of the carry amount within a range in which white stripes or black stripes are not generated between the print lines, it is possible to prevent the print image quality from being deteriorated.

  In addition, by making the carry amount different for each scan, the interval at which the ink droplets fall into the holes in the cloth medium M in the carry direction F can be appropriately made non-uniform.

  In this case, by changing the amount of deviation in one direction in steps, the positional deviation of the ink droplets that land on the cloth medium M can be made inconspicuous, so that it is possible to suppress a decrease in print image quality.

  Furthermore, after changing the amount of deviation stepwise in one direction, the amount of deviation of the ink droplets that land on the cloth medium M can be made less noticeable by changing the amount of deviation stepwise in the other direction. Therefore, it is possible to further suppress a decrease in print image quality.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, in the present embodiment, the cloth medium M is transported in the transport direction F, and the inkjet head 3 and the cloth medium M are relatively moved in the transport direction F. However, for example, a flatbed printer As described above, the inkjet head 3 (the head unit 2 or Y bar equipped with the inkjet head) is transported in the transport direction F to move the inkjet head 3 and the cloth media M relatively in the transport direction F. Also good.

  In the above embodiment, the setting of the deviation amount is not particularly described. However, for example, a deviation amount setting unit (variation amount setting unit) for setting the deviation amount is further provided, and the deviation amount is set according to the type of the media. The amount setting means may appropriately set the deviation amount by user setting or automatic setting. In this way, by making it possible to set the amount of deviation, for example, the generation of moire fringes can be appropriately suppressed according to the type of cloth media, the inclination state of the cloth media, and the like.

  In the above-described embodiment, the shift amount is always calculated, and the transfer mechanism 5 is controlled to be controlled by the control transfer amount obtained by adding the shift amount to the reference transfer amount. However, for example, whether or not the transfer amount is changed. It is good also as providing the selection means to select. In this case, when it is selected that the conveyance amount is changed by the selection unit, the conveyance mechanism 5 is controlled by the control conveyance amount obtained by adding the deviation amount to the reference conveyance amount, and the selection unit is selected not to change the conveyance amount. Controls the transport mechanism 5 according to the reference transport amount.

  Moreover, although the said embodiment demonstrated as what changes the relative moving amount | distance to the conveyance direction of an inkjet head and a medium by control of the control part 6, it replaced with control of the control part 6, or a control part. In conjunction with the control of 6, the operator may manually switch the relative movement amount of the inkjet head and the medium in the transport direction. In this case, in order to change the relative movement amount of the inkjet head and the medium in the conveyance direction for each scan within a range in which the resolution does not change, the relative movement amount of the inkjet head and the medium in the conveyance direction is changed. Switching means for manual switching by the operator is further provided. By providing such switching means, finer adjustment based on the operator's vision becomes possible.

DESCRIPTION OF SYMBOLS 1 ... Inkjet printer, 2 ... Head unit, 3 ... Inkjet head, 3a ... Nozzle, 4 ... Drive mechanism, 5 ... Conveyance mechanism, 6 ... Control part, 61 ... Head drive control part, 62 ... Discharge control part, 63 ... Media Transport control unit, 631... Reference transport amount calculation unit, 632. Fluctuation amount calculation unit, 633... Control execution unit, F. Transport direction, M.

Claims (7)

The inkjet head on which nozzles for discharging ink droplets are mounted is scanned in the scanning direction, and the inkjet head and the medium are moved relative to each other in the transport direction orthogonal to the scanning direction to perform printing on the medium. An inkjet printer,
By changing the relative movement amount of the inkjet head and the medium in the transport direction for each scan within a range in which the resolution does not change , the interval between dots formed on the medium is made nonuniform in the transport direction. An ink jet printer, characterized in that   The relative movement amount of the inkjet head and the medium in the transport direction is varied within a range in which white stripes or black stripes are not generated between print lines printed in each scan. The inkjet printer according to 1.   The inkjet printer according to claim 1, wherein a relative movement amount of the inkjet head and the medium in the transport direction is varied for each scan.   The inkjet printer according to claim 3, wherein a relative movement amount of the inkjet head and the medium in the transport direction is changed stepwise in one direction.   After the relative movement amount of the inkjet head and the medium in the conveyance direction is changed stepwise in one direction, the relative movement amount of the inkjet head and the medium in the conveyance direction is changed stepwise in the other direction. The inkjet printer according to claim 3, wherein   The inkjet printer according to claim 1, further comprising a fluctuation amount setting unit that sets a fluctuation amount that fluctuates a relative movement amount of the ink jet head and the medium in the transport direction. In order to change the relative movement amount of the inkjet head and the medium in the conveyance direction for each scan within a range in which the resolution does not change, the relative movement amount of the inkjet head and the medium in the conveyance direction. The inkjet printer according to claim 1, further comprising switching means for manually switching the operation.