JP2015150822A - Printer and ink jet head unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printer which performs printing for obtaining one printing image by dividing it into a plurality of paths without having a loop conveyance passage and facilitates drying of an ink.SOLUTION: A printer 1 comprises a first line type ink jet head 21 and a fifth line type ink jet head 41 which discharge a black ink. Second to fourth line type ink jet heads 22-24 are disposed between the first line type ink jet head 21 and the fifth line type ink jet head 41. Therefore, printing for forming an image is divided into a first path performed by driving the first line type ink jet head 21 and a second path performed by driving the fifth line type ink jet head 41 and the discharge amount of ink droplets in one path can be reduced in the printer 1. The first path and the second path are performed with a time difference, thereby drying of the ink droplets is facilitated.

Description

  The present invention relates to a printing apparatus including an inkjet head unit including a plurality of line-type inkjet heads, and the inkjet head unit.

  Pigment inks include those with high and low water resistance (fixability of ink to a print medium) and water resistance of ink fixed on recording paper. Here, when a large amount of ink with low abrasion resistance and water resistance is ejected onto the recording paper at a time, the drying of the ink becomes slow, and the printed image immediately after printing is easily damaged by contact or adhesion of water droplets. Become. In order to prevent such damage to the printed image, the printer described in Patent Document 1 circulates the recording paper along a loop-shaped conveyance path passing through the printing position by the inkjet head during printing, and printing is performed a plurality of times. It is done separately. That is, in Patent Document 1, printing for obtaining one print image is divided into a plurality of passes, thereby reducing the amount of ink ejected at one time toward the recording paper in one pass, and ink droplets. Promotes dryness.

JP 2006-256161 A

  In Patent Document 1, it is possible to divide the printing into a plurality of passes by rotating the printing paper along a loop-shaped conveyance path. However, if a loop-shaped conveyance path is mounted on the printing apparatus, there is a problem that downsizing of the apparatus is hindered.

  SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a printing apparatus that can promote drying of ink by dividing a plurality of passes for printing to obtain one print image without providing a loop-shaped conveyance path. And providing an inkjet head unit.

  In order to solve the above-described problems, a printing apparatus according to the present invention includes a conveyance unit that conveys a recording medium, a line-type first inkjet head that includes a nozzle that ejects ink of a first color, and the recording medium. A line-type second inkjet head having a nozzle that is disposed downstream of the first inkjet head in the transport direction and ejects a second color ink different from the first color ink; And a line-type third inkjet head that is disposed downstream of the second inkjet head in the transport direction and has a nozzle that ejects the ink of the first color.

  The printing apparatus of the present invention includes a first inkjet head and a third inkjet head as inkjet heads that eject the first color ink. Therefore, printing for obtaining one print image can be divided into a first pass performed by driving the first inkjet head and a second pass performed by driving the second inkjet head. Therefore, it is possible to reduce the amount of ink ejected at a time toward the recording medium in one pass, and to promote the drying of the first color ink ejected to the recording medium. In addition, a second inkjet head is disposed between the first inkjet head and the third inkjet head in the recording medium conveyance direction. As a result, the first inkjet head and the third inkjet head are arranged at positions separated from each other, so that the ink ejected by the first inkjet head is landed on the recording medium and the ink ejected by the third inkjet is recorded. There is a time difference between the impact on the medium. Therefore, drying of the ink is promoted by this time difference.

  In the present invention, in order to perform color printing, the ink of the first color is disposed downstream of the second inkjet head in the transport direction and upstream of the third inkjet head. In addition, it is preferable to include a line-type fourth inkjet head having a nozzle that ejects a third color ink different from the second color ink. According to the present invention, the distance between the first inkjet head and the third inkjet head is increased by the provision of the fourth inkjet head. Therefore, the time difference between the landing of the ink ejected by the first inkjet head on the recording medium and the landing of the ink ejected by the third inkjet head on the recording medium becomes large. Therefore, drying of the ink can be promoted.

  In the present invention, it is desirable that the nozzles of the first inkjet head and the nozzles of the third inkjet head are arranged at different positions when viewed from the transport direction. According to the present invention, the landing position on the recording medium of the ink ejected by the first inkjet head and the landing position on the recording medium of the ink ejected by the third inkjet can be shifted. Therefore, drying of each ink can be promoted.

  In the present invention, a line that is disposed downstream of the third inkjet head in the transport direction and has a nozzle that ejects light-transmitting ink having higher wear resistance and water resistance than the first color ink. A fifth inkjet head of the type can be provided. According to the present invention, the light-transmitting ink ejected from the fifth inkjet head is formed by the dots on the recording medium formed by the ink ejected by the first inkjet head and the ink ejected by the third inkjet. The dots on the recording medium can be covered to improve the abrasion resistance and water resistance of the printed image.

  Next, an inkjet head unit according to the present invention includes a line-type first inkjet head having a plurality of nozzles that eject ink of a first color in a first direction, and the first inkjet head unit. A line-type second inkjet head having a plurality of nozzles that are disposed in a second direction intersecting the direction and eject a second color ink different from the first color ink; And a line-type third ink-jet head that has a plurality of nozzles that are disposed in the second direction of the ink-jet head and eject the ink of the first color.

  The ink jet head unit of the present invention has a first ink jet head and a third ink jet head as ink jet heads for discharging the first color ink. Therefore, if the ink jet head unit is mounted on the printing apparatus, the first pass in which printing for obtaining one print image is performed by driving the first ink jet head and the second pass in which driving the second ink jet head is performed. Can be divided into multiple paths. Therefore, it is possible to reduce the amount of ink ejected at a time toward the recording medium in one pass, and to promote the drying of the first color ink ejected to the recording medium. In addition, a second inkjet head is disposed between the first inkjet head and the third inkjet head in the recording medium conveyance direction. As a result, the first inkjet head and the third inkjet head are arranged at positions separated from each other, so that the ink ejected by the first inkjet head is landed on the recording medium and the ink ejected by the third inkjet is recorded. There is a time difference between the impact on the medium. Therefore, drying of the ink is promoted by this time difference.

  In the present invention, in order to perform color printing, the ink of the first color and the ink of the second color are disposed between the second ink jet head and the third ink jet head. Can be provided with a line-type fourth inkjet head having a plurality of nozzles for ejecting different third color inks. According to the present invention, the distance between the first inkjet head and the third inkjet head is increased by the provision of the fourth inkjet head. Therefore, the time difference between the landing of the ink ejected by the first inkjet head on the recording medium and the landing of the ink ejected by the third inkjet on the recording medium becomes large. Therefore, drying of ink can be promoted.

  In the present invention, it is desirable that the nozzles of the first inkjet head and the nozzles of the third inkjet head are disposed at different positions when viewed from the second direction. According to the present invention, the landing position on the recording medium of the ink ejected by the first inkjet head and the landing position on the recording medium of the ink ejected by the third inkjet can be shifted. Therefore, drying of each ink can be promoted.

  In the present invention, there are provided a plurality of nozzles that are disposed in the second direction of the third inkjet head and eject light-transmitting ink having higher abrasion resistance and water resistance than the first color ink. A line-type fifth inkjet head may be provided. According to the present invention, the light-transmitting ink ejected from the fifth inkjet head is formed by the dots on the recording medium formed by the ink ejected by the first inkjet head and the ink ejected by the third inkjet. The dots on the recording medium can be covered to improve the abrasion resistance and water resistance of the printed image.

1 is a schematic configuration diagram of a main part of a printer to which the present invention is applied. It is explanatory drawing of the arrangement | sequence of the nozzle in a print head. 2 is a schematic block diagram of a printer control system. FIG. It is explanatory drawing of the arrangement | sequence of the nozzle in the printing head of a modification.

  A printer to which the present invention is applied will be described below with reference to the drawings.

(printer)
FIG. 1 is a schematic configuration diagram of a main part of the printer. FIG. 2 is an explanatory diagram of nozzle arrangement in the print head. As shown in FIG. 1, a printer (printing apparatus) 1 includes a print head 5, a paper conveyance path 6 extending via a printing position A by the print head 5, and a recording paper (recording medium) along the paper conveyance path 6. ) A transport mechanism 7 for transporting P is provided. The transport mechanism 7 is mounted on a platen unit 8 that faces the print head 5 with a predetermined gap below the print head 5 in the vertical direction. The transport mechanism 7 includes an endless transport belt 11 spanned between a plurality of guide rollers 9 and a drive roller 10, and a transport motor 12 that rotates the transport belt 11 by rotating the drive roller 10. The transport mechanism 7 transports the recording paper P at a predetermined speed by driving the transport motor 12.

  As shown in FIG. 2, the print head 5 (inkjet head unit) includes a first composite inkjet head 16 and a second composite inkjet head 17 having four sets of line-type inkjet heads. The first composite inkjet head 16 is arranged upstream of the second composite inkjet head 17 in the conveyance direction B of the recording paper P.

  The first composite ink-jet head 16 includes four sets of line-type ink-jet heads 21 to 24 arranged at predetermined intervals along the transport direction (second direction) B. The first line-type inkjet head 21 located at the uppermost stream in the conveyance direction B of the recording paper P ejects black ink, and the second line-type inkjet head 22 on the downstream side ejects cyan ink. Further, the third line type ink jet head 23 on the downstream side of the second line type ink jet head 22 ejects magenta ink, and the fourth line type ink jet head 24 on the downstream side ejects yellow ink.

  The first line-type inkjet head 21 includes a first nozzle row 36 in which a plurality of first nozzles 31 that discharge black ink are arranged in an intersecting direction (first direction) C that intersects the transport direction B. The second line type inkjet head 22 includes a second nozzle row 37 in which a plurality of second nozzles 32 that discharge cyan ink are arranged in the cross direction C. The third line-type inkjet head 23 includes a third nozzle row 38 in which a plurality of third nozzles 33 that discharge magenta ink are arranged in the intersecting direction C. The fourth line type inkjet head 24 includes a fourth nozzle row 39 in which a plurality of fourth nozzles 34 that discharge yellow ink are arranged in the cross direction C. The first nozzles 31 constituting the first nozzle row 36, the second nozzles 32 constituting the second nozzle row 37, the third nozzles 33 constituting the third nozzle row 38 and the fourth nozzle row 39 are constituted. The fourth nozzles 34 are provided at overlapping positions when viewed from the transport direction B.

  The second composite inkjet head 17 includes four sets of line-type inkjet heads 41 to 44 arranged at a predetermined interval along the transport direction B. The fifth line-type inkjet head 41 located at the uppermost stream in the conveyance direction B of the recording paper P ejects black ink, and the sixth line-type inkjet head 42 on the downstream side ejects cyan ink. Further, the third line type inkjet head 43 on the downstream side of the seventh line type inkjet head 42 ejects magenta ink, and the eighth line type inkjet head 44 on the downstream side ejects yellow ink.

  The fifth line-type inkjet head 41 includes a fifth nozzle row 56 in which a plurality of fifth nozzles 51 that discharge black ink are arranged in the intersecting direction C. The sixth line-type inkjet head 42 includes a sixth nozzle row 57 in which a plurality of sixth nozzles 52 that discharge cyan ink are arranged in the cross direction C. The seventh line-type inkjet head 43 includes a seventh nozzle row 58 in which a plurality of seventh nozzles 53 that discharge magenta ink are arranged in the intersecting direction C. The eighth line type inkjet head 44 includes an eighth nozzle row 59 in which a plurality of eighth nozzles 54 that discharge yellow ink are arranged in the cross direction C.

  The nozzle interval D in the intersecting direction C of the nozzles 51 to 54 of the second composite inkjet head 17 is equal to the nozzle interval D in the intersecting direction C of the nozzles 51 to 54 of the first composite inkjet head 16. Further, each fifth nozzle 51 constituting the fifth nozzle row 56, each sixth nozzle 52 constituting the sixth nozzle row 57, and each seventh nozzle 53 and eighth nozzle 59 constituting the seventh nozzle row 58 are provided. Each of the eighth nozzles 54 is provided at a position that overlaps when viewed in the transport direction B.

  Here, the nozzles 51 to 54 of the second composite inkjet head 17 are positioned between the nozzles 31 to 34 of the first composite inkjet head 16 when viewed from the transport direction B. That is, the nozzles 51 to 54 of the second composite inkjet head 17 are provided at positions offset from the nozzles 31 to 34 of the first composite inkjet head 16 in the ½ cross direction C of the nozzle interval D.

(Control system)
FIG. 3 is a schematic block diagram of the control system of the printer 1. The control system of the printer 1 includes a control unit 61 that includes a CPU. The control unit 61 is connected to a communication unit 62 that connects an external device such as a computer and the printer 1 so as to communicate with each other. The communication unit 62 receives image data supplied from an external device and inputs it to the control unit 61. The control unit 61 is connected to the print head 5 and the transport motor 12 via a device driver (not shown). A memory 63 is connected to the control unit 61. The memory 63 stores and holds a color processing lookup table 64 and an SML table 65. The control unit 61 includes an image processing unit 66 and a print control unit 67.

  The image processing unit 66 includes a rendering unit 66a, a color conversion unit 66b, a halftone processing unit 66c, and a print data generation unit 66d.

  The rendering unit 66a renders the image data input to the control unit 61, and converts each pixel of the image data into RGB multi-value data. When the RGB multi-value data is generated, the color converter 66b refers to the color processing lookup table 64 and converts the RGB multi-value data of each pixel into ink amount data of each ink droplet. The color processing lookup table 64 stores and holds a color configured by a combination of R, G, and B and ink amount data of each ink droplet in association with each other. When the ink amount data is generated, the halftone processing unit 66c determines the ink amount data of each ink droplet forming each pixel based on the SML table 65 and has a diameter different from that of a blank dot that does not eject ink. Conversion into dot ratio data indicating the ratio of three types of ink droplets. The SML table 65 stores and holds the color gradation value based on each ink amount data and the usage ratios of the three types of dots: blank dots, small dots, medium dots, and large dots.

  The print data generation unit 66d generates print data in a format that can be interpreted by the printer 1 from the dot ratio data generated by the halftone processing unit 66c. The print data is a command group for ejecting ink from each nozzle of the print head 5, and sets the nozzle to be driven and the dot size of the ink droplet ejected from the nozzle.

  Here, the print data generation unit 66d generates print data for printing each pixel formed on the recording paper P in two passes (printing in two divided prints). That is, the print data generation unit 66d selects the first nozzle 31 to be driven from the first nozzle row 36 of the first line-type inkjet head 21 based on the dot ratio data of each pixel, and ejects ink from the nozzle 31. The droplet dot size is set, the nozzle 51 to be driven is selected from the fifth nozzle row 56 of the fifth line-type inkjet head 41, and print data for setting the dot size of the ink droplet ejected from the nozzle 51 is generated. As a result, the print data generation unit 66d determines the dot size of the ink droplets ejected from the nozzles 31 of the first line-type inkjet head 21 and the dot size of the ink droplets ejected from the nozzles 51 of the fifth line-type inkjet head 41. Then, print data that is smaller than the dot size of the ink droplet when the pixel is formed by driving the nozzle 31 of the first line type inkjet head 21 is generated.

  In addition, the print data generation unit 66d selects the nozzle 32 to be driven from the second nozzle row 37 of the second line-type inkjet head 22 based on the dot ratio data of each pixel, and the ink droplets ejected from the nozzle 32. The dot size is set, the nozzle 52 to be driven is selected from the sixth nozzle row 57 of the sixth line-type inkjet head 42, and print data for setting the dot size of the ink droplet ejected from the nozzle 52 is generated. Similarly, based on the dot ratio data of each pixel, the nozzle 33 driven from the third nozzle row 38 of the third line type inkjet head 23 is selected, and the dot size of the ink droplets ejected from the nozzle 33 is set. The nozzle 53 to be driven is selected from the seventh nozzle row 58 of the seventh line-type inkjet head 43, and print data for setting the dot size of the ink droplet ejected from the nozzle 53 is generated. Further, based on the dot ratio data of each pixel, the nozzle 34 to be driven is selected from the fourth nozzle row 39 of the fourth line-type inkjet head 24, the dot size of the ink droplet ejected from the nozzle 34 is set, and the first The nozzle 54 to be driven is selected from the eighth nozzle row 59 of the 8-line inkjet head 44, and print data for setting the dot size of the ink droplet ejected from the nozzle 54 is generated.

(Printing process)
When the printer 1 is supplied with image data from an external device, the image processing unit 66 converts the image data into RGB multi-value data, ink amount data of each ink droplet, and dot ratio data in this order. The image processing unit 66 generates print data based on the dot ratio data.

  When the print data is generated, the print control unit 67 drives the transport motor 12 to transport the recording paper P along the transport path at a predetermined speed. Further, the print head 5 is driven based on the print data, and printing is performed on the recording paper P conveyed at the print position A.

  Here, in this example, each pixel of the image data is printed in two passes. Accordingly, it is possible to reduce the amount of ink droplets ejected toward the recording paper P at a time in one pass, and promote drying of the ink droplets ejected onto the recording paper P.

  Further, in this example, three line-type ink jets that discharge different color inks between two line-type ink jet heads 21 to 24 and 41 to 44 that discharge the same color ink in the conveyance direction B of the recording paper P. A head is disposed. As a result, the two line-type inkjet heads 21 to 24 and 41 to 44 that eject the same color ink are arranged at separated positions, and the ink droplets ejected by the line-type inkjet heads 31 to 34 located upstream in the transport direction B There is a time difference between the landing on the recording paper P and the landing on the recording paper of the ink droplets ejected from the line-type inkjet heads 41 to 44 located downstream in the transport direction B. Therefore, drying of ink droplets is promoted by this time difference.

  Further, in this example, in the two line-type inkjet heads 21 to 24 and 41 to 44 that discharge the same color ink, the nozzles 31 to 34 are different from the nozzles 51 to 54 when viewed from the transport direction B. Provided in position. As a result, the landing positions on the recording paper P of the ink droplets ejected from the nozzles 31 to 34 and 51 to 54 of the two line-type inkjet heads 21 to 24 and 41 to 44 that eject the same color ink can be shifted. As a result, drying of each ink droplet can be promoted.

(Modification)
FIG. 4 is a schematic configuration diagram of a modified print head. Since the print head (inkjet head unit) 5A of this example has the same configuration as the print head 5 of the above example, the corresponding components are denoted by the same reference numerals and description thereof is omitted. .

  In this example, a ninth line type inkjet head 70 that discharges light-transmitting ink having higher abrasion resistance and water resistance than each color ink is disposed at the most downstream side in the transport direction B of the second composite inkjet head 17. . The ninth line-type inkjet head 70 includes a ninth nozzle row 72 in which a plurality of ninth nozzles 71 that eject light transmissive ink are arranged in the intersecting direction C. In this example, each ninth nozzle 71 is provided at a position that overlaps each nozzle 31 to 34 of the first composite inkjet head 16 when viewed from the transport direction B.

  Here, in the printer (printing apparatus) equipped with the print head 5A of this example, the print data generation unit 66d of the image processing unit 66 prints each pixel to be formed on the recording paper P in two passes based on the image data. Print data to be printed (printed in two divided prints) is generated, and each of the ninth nozzles 71 of the ninth line-type inkjet head 70 is driven with respect to the pixel formation region on the recording paper P to transmit large dots of light. Print data for ejecting the specific ink is generated. At the time of printing, light transmissive ink is ejected from each of the ninth nozzles 71 of the ninth line-type inkjet head 70, and the printed image formed on the recording paper P is covered with the light transmissive ink. Therefore, in this example, it is possible to reduce the amount of ink droplets ejected toward the recording paper P at a time in one pass, and promote drying of the ink droplets ejected onto the recording paper P. Further, it is possible to cover the printed image with light transmissive ink and improve its abrasion resistance and water resistance.

1 .. Printer, 2 .. Computer, 5. 5A .. Print head (inkjet head unit), 6 .. Paper transport path, 7 .... Transport mechanism, 8 .... Platen unit, 9 .... Guide roller, 10. · Driving roller, 11 · · Conveyor belt, 12 · · Conveyor motor, 16 · · First composite ink jet head, 17 · · Second composite ink jet head, 21 to 24 · · First to fourth line type ink jet heads, 31 ˜34... First to fourth nozzles 36 to 39... First to fourth nozzle rows 41 to 44 .. Fifth to eighth line type ink jet heads 51 to 54. 56 to 59 .. 5th to 8th nozzle row 61.. Control unit 62 62 Communication unit 63 Memory 64 Color processing lookup table 65 SML table 6 ..Image processing unit, 66a ..Rendering unit, 66b ..Color conversion unit, 66d ..Print data generation unit, 66c ..Halftone processing unit, 67..Print control unit, 70..Ninth inkjet head ( 5th inkjet head), 71 ... 9th nozzle, 72 ... 9th nozzle row, A ... printing position, B ... conveying direction (second direction), C ... cross direction (first direction) ), D..Nozzle spacing, P .. Recording paper (recording medium)

Claims (8)

A transport unit for transporting the recording medium;
A line-type first inkjet head having a nozzle for discharging the first color ink;
A line-type second ink jet head having a nozzle that is disposed downstream of the first ink jet head in the transport direction of the recording medium and that ejects a second color ink different from the first color ink. When,
A line-type third inkjet head disposed downstream of the second inkjet head in the transport direction and having a nozzle that ejects the first color ink;
A printing apparatus comprising:   Disposed downstream of the second ink jet head in the transport direction and upstream of the third ink jet head, and different from the first color ink and the second color ink. The printing apparatus according to claim 1, further comprising a line-type fourth inkjet head having a nozzle that ejects ink of three colors.   The printing apparatus according to claim 1, wherein the nozzles of the first inkjet head and the nozzles of the third inkjet head are arranged at different positions when viewed from the transport direction.   A line type fifth having a nozzle that is disposed downstream of the third inkjet head in the transport direction and that discharges light-transmitting ink having higher abrasion resistance and water resistance than the first color ink. The printing apparatus of any one of Claim 1 thru | or 3 provided with this inkjet head. A line-type first inkjet head having a plurality of nozzles for discharging ink of a first color in a first direction;
A line type having a plurality of nozzles arranged in a second direction intersecting the first direction of the first inkjet head and ejecting a second color ink different from the first color ink. A second inkjet head;
A line-type third ink-jet head having a plurality of nozzles disposed in the second direction of the second ink-jet head and discharging the ink of the first color;
An inkjet head unit comprising:   Nozzle disposed between the second inkjet head and the third inkjet head and ejecting a third color ink different from the first color ink and the second color ink. The inkjet head unit according to claim 5, further comprising a line-type fourth inkjet head having a plurality of lines.   The inkjet head unit according to claim 5 or 6, wherein the nozzles of the first inkjet head and the nozzles of the third inkjet head are arranged at different positions when viewed from the second direction.   A line-type first nozzle having a plurality of nozzles disposed in the second direction of the third inkjet head and ejecting light-transmitting ink having higher abrasion resistance and water resistance than the first color ink. The inkjet head unit according to claim 5, comprising 5 inkjet heads.

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