JP6379507B2 - Printing apparatus and printing method - Google Patents

Description

  The present invention relates to printing.

  The printing apparatus normally forms an image by sequentially landing ink on the print medium while relatively moving the print head and the print medium. Even when the print head is tilted, a technique is known in which print data is adjusted according to the tilt amount of the print head in order to normally print an image with the ink landing position being brought close to a desired position (for example, Patent Document 1).

JP 2005-96369 A

  The problem of the prior art is that the processing load for adjusting print data is heavy. The above adjustment may be performed across pages. In such a case, the processing load becomes heavy. As a result, processing takes time, and the time required for printing becomes long. Note that the purpose of adjusting the print data is not limited to that according to the inclination of the print head, but includes that relating to the fact that an image cannot be printed normally due to various factors. In addition, downsizing of the apparatus, cost reduction, resource saving, ease of manufacture, improvement in usability, and the like have been desired.

  SUMMARY An advantage of some aspects of the invention is to solve at least one of the problems described above, and the invention can be implemented as the following forms.

  According to one aspect of the invention, a printing apparatus is provided. The printing apparatus includes: a line head in which a plurality of dot recording elements that form dots on a recording medium are arranged over the recording width of the recording medium; and print data for dot recording by the line head. A correction unit that executes correction for reducing a shift of a recording position due to a dot recording element and deletion of a part of the print data or a part of the print data after the correction. According to this embodiment, the processing load is reduced. This is because part of the print data or part of the print data after modification is deleted, so that the processing load for modification is reduced for the part to be deleted.

  In the above embodiment, a determination unit that determines whether or not to delete a part of the print data or a part of the modified print data is provided; the correction unit is determined not to perform the deletion In this case, the data to be deleted when the deletion is performed is included in the corrected print data. According to this aspect, it is possible to determine whether to reduce the processing load or suppress deterioration in image quality. This is because if the deletion is not performed, the deterioration of the image quality is suppressed.

  In the above embodiment, the determination unit determines that the deletion is performed when the print data includes data for printing an image unnecessary as a printed material on the edge of the recording medium. According to this aspect, the determination can be appropriately executed. This is because if the print data includes data for printing an image unnecessary as a printed material on the edge of the recording medium, the deleted data is likely to correspond to an image unnecessary as a printed material.

  In the above aspect, even when the data for printing the unnecessary image is included, the determination unit performs the deletion if at least a part of the printing of the image necessary as a printed matter cannot be executed due to the shift. Decide not to implement. According to this aspect, the above determination can be executed more appropriately.

  In the above embodiment, the modification unit forms the dot at a position corresponding to the outside of the print area by the modification or the print data modified as data for forming the dot at a position corresponding to the outside of the print area by the modification. The deletion is executed on the modified print data modified as data. According to this embodiment, the processing load is reduced. For print data that is modified as data to form dots at positions corresponding to outside the print area by modification, or print data after modification that has been modified as data to form dots at positions corresponding to outside the print area by modification, This is because if deletion is executed, it is not necessary to adjust data across pages.

  In the above embodiment, the line head includes a plurality of print heads; each of the plurality of dot recording elements is provided in any one of the plurality of print heads. According to this embodiment, the displacement of the print head relative to the line head can be reduced.

  The present invention can be realized in various forms other than the above. For example, the present invention can be realized in the form of a printing method, a program for realizing the method, a non-temporary storage medium storing the program, a printing system, a data processing method, and the like.

FIG. The figure which looked at the head from the lower part. 6 is a flowchart illustrating printing processing. The figure explaining printing in case correction is not implemented. The figure which shows arrangement | positioning of the dot by the corrected dot data. The figure explaining printing when deletion of data and movement between pages are not carried out. The figure which shows the image containing an unnecessary part. The figure explaining deletion of data. The figure explaining printing in case data deletion is performed. The figure which shows the data arrangement | positioning by the dot data before correction. FIG. 5 is a diagram for explaining printing when page-to-page movement is performed.

  FIG. 1 is a schematic sectional view of the printer 1. The printer 1 forms an image with UV ink on a medium. The UV ink is cured when irradiated with ultraviolet rays. This curing is caused by a photopolymerization reaction occurring in the ultraviolet curable resin contained in the UV ink. The medium in the present embodiment is roll paper S wound in a roll shape. The roll paper S corresponds to an example of the “recording medium” of the present invention. The recording medium is not limited to roll paper, and a film wound in a roll shape may be used.

  An image forming method using the printer 1 will be described. The printer 1 is a so-called line printer. Roll paper S wound in a roll shape is supplied to the printing area by transport rollers 2A, 2B, etc., and is transported at a constant speed from the upstream side to the downstream side in the paper transport direction. The roll paper S located in the printing area faces the head 4 while being supported by the platen 3 from the back side.

  The head 4 is a so-called line head, and includes a head Y, a head M, a head C, and a head K. Each of the heads Y, M, C, and K is disposed across the width direction of the roll paper S. The head Y ejects yellow UV ink, the head M ejects magenta UV ink, the head C ejects cyan UV ink, and the head K ejects black UV ink toward the roll paper S.

  On the lower surface of each head 4 (the surface facing the roll paper S), a large number of nozzles are arranged at predetermined intervals in the paper width direction. Each nozzle functions as a dot recording element by ejecting UV ink. The paper width direction is a direction orthogonal to the paper transport direction. When the roll paper S passes under the head 4, UV ink is ejected from the head 4, thereby forming dots of each color on the roll paper S.

  Thereafter, the roll paper S faces the irradiation unit 10. The irradiation unit 10 irradiates ultraviolet rays toward the roll paper S moving in the paper conveyance direction. As a result, the dots formed on the roll paper S are cured. Thus, the image forming process on the roll paper S is completed. The roll paper S on which the image is formed is wound up into a roll again.

  The operations of the transport rollers 2A and 2B and the head 4 described above are controlled by the control unit 30 provided in the printer 1. The control unit 30 can exchange data with an external device. For example, image data for printing can be received from the external PC 90 via Ethernet (registered trademark). The image data corresponds to an example of “print data” of the present invention, and the control unit 30 corresponds to an example of “modification unit” and “decision unit” of the present invention.

  FIG. 2 is a view of the head 4 as viewed from below. Each head Y, M, C, K includes a plurality of print heads 80. The print heads 80 are staggered as shown in FIG. Each print head 80 includes a plurality of nozzles.

  FIG. 3 is a flowchart showing the printing process. The printing process is executed by the control unit 30. The control unit 30 stores a program for executing print processing. The trigger when the control unit 30 starts the printing process is that the image data for printing is received from the external device.

  First, the received image data is converted into dot data (step S100). The dot data is data indicating the presence or absence of dot formation for each pixel for each YMCK. Since the printer 1 prints at a resolution of 600 dpi, dot data is generated accordingly. The control unit 30 writes the generated dot data to a built-in memory. The subsequent steps are executed for the dot data written in the memory.

  Next, the dot data is corrected (step S200). In order to explain the modification of the dot data, printing in the case where the modification is not performed will be described.

  FIG. 4 is a diagram for explaining printing in a case where no correction is performed. FIG. 4A illustrates the arrangement of dots indicated by dot data (hereinafter referred to as “data arrangement”). The data arrangement shown in FIG. 4A is an extract of 4 × 8 pixels from the dot data. In the following description, 4 × 8 pixels are assumed to be one page. Circles shown in FIG. 4A indicate dot positions. The type of hatching applied to the circle indicates the difference in dot color.

  FIG. 4B shows the positions of dots formed on the roll paper S according to the dot data shown in FIG. 4A (hereinafter referred to as “landing positions”). As shown in FIG. 4B, the landing position has a deviation in the paper conveyance direction with respect to the dot data. Hereinafter, this deviation is referred to as “conveyance direction deviation”.

  The conveyance direction deviation is caused by various causes. For example, as shown in FIG. 4, the arrangement of the nozzles Nz is caused by deviation from the ideal arrangement. The displacement of the nozzles Nz is caused by a displacement of the mounting position of the head 4 with respect to the printer 1 or a displacement of the mounting position of the print head 80 with respect to the head 4. The deviation in the transport direction is also caused by the flight bend of the ejected ink. The flight bend is caused by, for example, ink clogging of the nozzle Nz.

  FIG. 5 shows the data arrangement modified in step S200. This modification is for compensating for a deviation in the conveyance direction. In order to realize this compensation, the control unit 30 stores in advance compensation values for each column in the paper width direction. The compensation value is determined by a previously performed experiment.

  If one side in the paper width direction is defined as the back side and the other side is defined as the near side, in the case illustrated in FIG. A compensation value of -1 means that the arrangement is shifted by one pixel upstream in the paper transport direction. The compensation value in the second row from the back is 0. A compensation value of 0 means that no compensation is required. The compensation value of the foremost column is +2. The compensation value of +2 means that the arrangement is shifted by two pixels on the downstream side in the paper conveyance direction.

  Subsequently, it is determined whether the modified data arrangement overlaps with the data arrangement of the previous and subsequent pages (step S300). In the modification shown in FIG. 5, the data arrangement that was originally 8 pixels in the paper conveyance direction is expanded to 11 pixels by the modification. For example, if there are no pages to be printed continuously before and after printing this page, there is no overlap with the data arrangement of the previous and next pages. Alternatively, when a sufficiently long margin is set, there is no overlap with the data arrangement of the previous and subsequent pages.

  In contrast, when multiple pages are printed continuously and the margin in the transport direction is short, if the data layout is expanded in the paper transport direction by modification, the data layout of the previous and subsequent pages overlaps. End up.

  If there is no overlap with previous and subsequent pages (step S300, NO), empty data is added to the corrected dot data (step S800). FIG. 6A shows a data arrangement to which empty data is added. FIG. 6A shows empty data by a broken-line circle. No dot is formed at the position where the empty data is added. The addition of empty data is performed to shape the data arrangement into a rectangular shape.

  Thereafter, printing is executed according to the dot data (step S900), and the printing process is finished. FIG. 6B shows the landing position when printing is performed according to the dot data shown in FIG. As shown in FIG. 6B, the deviation in the transport direction is compensated, and printing is executed according to the dot data before modification.

  On the other hand, if the modified data arrangement overlaps with the previous and next pages (step S300, YES), it is determined whether there is an unnecessary portion in the image (step S400). FIG. 7 illustrates an image including an unnecessary part. This image includes a cut line indicated by an elliptical dotted line. Since the printed matter of this image is finally cut off by the cut line and used, the outside of the cut line is a substantially unnecessary image. The determination in step S400 is executed based on whether or not such a cut line is included, for example.

  If there is an unnecessary part in the image (step S400, YES), it is determined whether printing of the part necessary for the image can be normally executed even if the data protruding from the page is deleted from the dot data (step S500). This determination will be described in detail later.

  Even if the data that protrudes from the page is deleted from the dot data, if the printing of the necessary portion of the image can be executed normally (step S500, YES), the data that protrudes from the page is deleted from the dot data (step S600).

  FIG. 8 is a diagram for explaining this deletion. If there are no margins at both ends in the transport direction in the dot data before modification (FIG. 4A), some dots protrude from the edge of the page in the dot data after modification. As shown in FIG. 8, the farthest column is shifted by one pixel upstream, so that the dot located most upstream protrudes from the page. Therefore, the data corresponding to this dot is deleted. In the case of the foremost line and the second line from the near side, the data corresponding to the dots protruding downstream are deleted.

  Subsequently, empty data is added to the deleted dot data (step S800). As shown in FIG. 9A, when the deletion is executed, the same number of empty data as the number of deleted dots is added.

  Finally, printing is executed according to the dot data (step S900). FIG. 9B shows a landing position when data deletion (step S600) is executed. As shown in FIG. 9B, the displacement in the transport direction is compensated, while a dot defect occurs. This loss is caused by data deletion.

  The above-described determination in step S500 is executed based on the positional relationship between a portion necessary as an image and the dot defect. That is, if all the missing dots correspond to an unnecessary part as an image, the part necessary as an image can be printed normally. On the other hand, if at least a part of the missing dots corresponds to a portion necessary for an image, the portion necessary for the image cannot be printed normally. Therefore, step S500 is realized by examining whether or not all the missing dots correspond to a necessary portion as an image.

  However, in the present embodiment, in order to simplify step S500, the determination is performed by a method described below instead of the above method. The method will be described with reference to FIG. In the case of FIG. 7, the gap between the image of the necessary portion and the upstream end of the page is length L1. Accordingly, it is confirmed on the upstream side that if the number of dots in each row deleted on the upstream side is equal to or less than the number of pixels corresponding to the length L1, the necessary portion can be printed normally. If it is determined whether or not the maximum number of dots to be deleted on the upstream side is equal to or less than the number of pixels corresponding to the length L1, the determination in step S400 is realized on the upstream side.

  In the case shown in FIG. 8, the maximum number of dots deleted on the upstream side is one dot in the innermost row. In this embodiment, since it is 600 dpi, the length of one dot (one pixel) is 0.0423 mm. As shown in FIG. 7, since 0.0423 mm is shorter than the length L1, it is determined that printing of a necessary portion on the upstream side can be executed normally.

  In the case shown in FIG. 8, the maximum number of dots deleted on the downstream side is 2 dots. The length for 2 dots is 0.0847 mm. Since 0.0847 mm is shorter than the length L2, it is determined that printing of a necessary portion can be normally executed also on the downstream side. According to such a method, step S400 is realized by setting only one column as a determination target for each of the upstream side and the downstream side.

  On the other hand, when there is no unnecessary part in the image (step S400, NO), or when the necessary part cannot be printed normally (step S500, NO), instead of executing the above deletion, dots that protrude from the page are displayed. Move to the previous or next page (step S700). This movement will be described with reference to FIGS.

  FIG. 10 shows a data arrangement based on dot data before modification. This dot data is data for four pages. FIG. 11A shows the data arrangement after modification and movement. FIG. 11B shows the landing positions according to the data arrangement shown in FIG.

  As shown in FIG. 11 (a), the second column from the back is one pixel downstream, the third column from the back is two pixels downstream, and the fourth column from the back (frontmost column) is downstream. Three pixels are modified on the side.

  As shown in FIG. 11A, the dot data of the third page includes data of dots that have been moved out of the second page due to modification. Similarly, the dot data on the fourth page includes dot data that has been moved out of the third page due to the modification. The same applies to the second page (not shown). The dots that protrude from the fourth page due to the modification are included in the newly added fifth page.

  After adding empty dots to the dot data of the first and last pages (first and fifth pages) (step S800) and printing according to the dot data (step S900), as shown in FIG. Landing according to the dot data. Note that FIG. 11B illustrates a state in which the page division of dot data is virtually separated in the paper conveyance direction with a boundary as a boundary. Actually, there is no gap between pages, and images are continuously formed.

According to the above embodiment, at least the following effects can be obtained.
(A) When part of the dot data is deleted, the processing load is lighter than when dot data is moved between pages.
(B) By using the determination based on the data analysis (steps S400 and S500), it is possible to prevent normal printing of a portion necessary as an image.
(C) Since the compensation value is set for each nozzle, it is possible to compensate for the deviation of the landing position due to various factors. In particular, since the head 4 is a line head, such compensation is effective.

  The present invention is not limited to the embodiments, examples, and modifications of the present specification, and can be implemented with various configurations without departing from the spirit of the present invention. For example, the technical features in the embodiments, examples, and modifications corresponding to the technical features in the embodiments described in the summary section of the invention are to solve some or all of the above-described problems, or In order to achieve part or all of the effects described above, replacement or combination can be performed as appropriate. If the technical feature is not described as essential in this specification, it can be deleted as appropriate. For example, the following are exemplified.

Deletion of a part of dot data may be executed prior to dot data modification or may be executed simultaneously.
The modification of the dot data and the deletion of a part of the dot data may be executed together with the generation of the dot data.

  The determination of whether or not there is an unnecessary part in the image may be performed based on information directly indicating whether or not there is an unnecessary part in the image, for example. This information may be transmitted along with the image data.

  It is not necessary to determine whether there is an unnecessary part in the image (step S400). In this case, when it overlaps with the previous and subsequent pages (step S300, YES), the data protruding from the page may be deleted (step S600).

  It is not necessary to determine whether or not printing of a necessary part as an image can be normally executed (step S500). In this case, when there is an unnecessary part in the image (step S400, YES), the data protruding from the page may be deleted (step S600).

  If there is an unnecessary part as an image in the center part instead of the edge part of the page, the dot data of that part may be deleted. If data deletion is performed prior to dot data modification, the processing load required for modification is reduced. Furthermore, the amount of data transferred to the head can be reduced.

A device group including an external PC in addition to the printing device may constitute the printing system. For example, it may be configured as follows. At least part of the generation, correction, and deletion of the dot data may be executed by an external PC. For example, the external PC may execute up to the generation of dot data, or may execute all of them.
A RIP (raster image processor) may be added to the printing system. The RIP may be configured as hardware connected between an external PC and a printing apparatus. In this case, the RIP may execute up to the generation of dot data, or all of them may be executed.
Such an external PC or RIP may be regarded as an example of a modification unit or a determination unit.

The absolute value of the compensation value may take a value smaller than 1.
The shift compensation does not have to completely cancel the shift, and may reduce the shift by compensating a part of the shift.
A cylindrical rotating drum may be used as the platen.
The line head may comprise only one print head.
A serial head may be used instead of the line head.
A normal ink may be used instead of the UV ink.
Instead of the printing method for ejecting ink, printing may be performed using another printing method, for example, a thermal method.

DESCRIPTION OF SYMBOLS 1 ... Printer 2A ... Conveyance roller 2B ... Conveyance roller 3 ... Platen 4 ... Head 10 ... Irradiation unit 30 ... Control part 80 ... Print head 90 ... External PC
S ... Roll paper Y ... Head M ... Head C ... Head K ... Head Nz ... Nozzle

Claims (3)

A line head in which a plurality of dot recording elements for forming dots on a recording medium are arranged over the recording width of the recording medium;
The dot data is modified so as to correct the deviation of the dot landing position due to the error in the mounting position of the line head, the modified dot data, the first image, and the necessary area in the first image And a creation unit for creating print data based on data for designating unnecessary areas,
The creation unit creates print data of a second image following the print data of the first image, and the line head prints across the first image and the second image. , creates print data to include the necessary area included in the first image, generates print data such that the do not include a non-procedure region included in the first image, the second image Is an image printed on the next page of the first image,
Printing device. The creation unit creates print data so as to include the unnecessary area when at least a part of the necessary area cannot be printed when printed with print data created so as not to include the unnecessary area. The printing apparatus according to 1. A printing method using a line head in which a plurality of dot recording elements for forming dots on a recording medium are arranged over the recording width of the recording medium,
The dot data is modified so as to correct the deviation of the dot landing position due to the error in the mounting position of the line head, the modified dot data, the first image, and the necessary area in the first image And creating the print data based on the data that specifies the unnecessary area,
In the creation procedure, when the print data of the second image is created following the print data of the first image, and the line head prints across the first image and the second image, , creates print data to include the necessary area included in the first image, generates print data such that the do not include a non-procedure region included in the first image, the second image Is an image printed on the next page of the first image,
Printing method.

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