Head for liquid discharge device and liquid discharge device comprising the same

Abstract

To enable printing processing to be performed with different printing resolution, in performing printing using the same head and prevent a plurality of heads from positionally shifting from each other, in performing printing using the heads.SOLUTION: A head for a liquid discharge device has a nozzle group including a plurality of nozzles. The head further has a nozzle surface in a regular hexagonal shape on which the nozzle group is arranged when viewed from a nozzle axis direction and six side surfaces adjacent to six sides of the nozzle surface. In a state where the head is mounted on the liquid discharge device, the nozzle group is configured so that arrangement densities of the plurality of nozzles in a crossing direction crossing the nozzle axis direction are different between when the head is in a predetermined first printing posture and a second printing posture in which a rotation angle around a predetermined rotation axis which is parallel to the nozzle axis direction is equal to a predetermined angle with respect to the first printing posture.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a liquid ejection device equipped with a head that ejects liquid such as ink onto a recording medium. [Background technology]

[0002] For example, as disclosed in Patent Document 1, an inkjet printer is known that includes an ink head in which a large number of ink ejection ports are arranged and which has an ink ejection region that is hexagonal in plan view. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-311959 Summary of the Invention [Problem to be solved by the invention]

[0004] In a liquid ejection device that ejects liquid, there are cases where it is required to perform printing processes at different print resolutions using the same head. However, the technology disclosed in Patent Document 1 does not allow for such changes in print resolution. Furthermore, for example, if an attempt is made to adjust the print resolution by arranging multiple heads side by side, misalignment between the heads may occur, and the desired print resolution may not be achieved.

[0005] Therefore, the present disclosure aims to enable printing processes to be performed at different print resolutions when printing using the same head, and to prevent misalignment between heads when printing using multiple heads. [Means for solving the problem]

[0006] In order to solve the above problems, one aspect of the present disclosure is a head for a liquid ejection device having a nozzle group including a plurality of nozzles that eject liquid onto the surface of a recording medium, wherein when viewed from a nozzle axis direction of the plurality of nozzles, the head has a regular hexagonal nozzle surface on which the nozzle group is arranged, and six side surfaces adjacent to six sides of the nozzle surface, and when attached to the liquid ejection device, the nozzle group is configured so that the arrangement density of the plurality of nozzles in a direction intersecting the nozzle axis direction differs when the head is in a predetermined first printing position and when the head is in a second printing position in which the rotation angle around a predetermined rotation axis parallel to the nozzle axis direction forms a predetermined angle with respect to the first printing position. [Effects of the Invention]

[0007] According to one aspect of the present disclosure, when printing using the same head, the present disclosure can perform printing processes at different print resolutions, and when printing using multiple heads, can prevent misalignment between the heads. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view showing a schematic configuration of a liquid ejection device according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a plan view of the head in the first printing position. [Figure 3] FIG. 3 is a partial enlarged view of the head in the first printing position of FIG. [Figure 4] FIG. 4 is a plan view of the head in the second printing position. [Figure 5] FIG. 5 is a partial enlarged view of the head in the second printing position of FIG. [Figure 6] FIG. 6 is a schematic diagram showing how a plurality of heads are arranged in combination. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The same or corresponding elements throughout the drawings will be designated by the same reference numerals, and redundant description will be omitted. The present disclosure is not limited to the embodiments, and additions, deletions, and modifications may be made without departing from the spirit of the present disclosure.

[0010] [Configuration of liquid ejection device] Fig. 1 is a plan view showing a schematic configuration of a liquid ejection device 1 (hereinafter also referred to as "device 1") according to an embodiment of the present disclosure. Fig. 1 shows the configuration of the device 1 as seen from the direction of the rotation axis X. In addition, the head unit 2 in the first printing position is shown by a solid line, and the head unit 2 in the second printing position is shown by a dashed line.

[0011] The device 1 is, for example, an inkjet printer that performs a printing process in which liquid, such as ink, is ejected from a head 3 to form characters, images, etc., on a recording medium M. The device 1 is, for example, a line head type, and forms an image by ejecting liquid from a fixedly arranged head unit 2 onto a sheet-like recording medium M transported in a transport direction P1. As will be described later, when the head 3 is attached to the device 1, a nozzle group 16 including a plurality of nozzles 15 provided on the head 3 is configured such that the arrangement density of the plurality of nozzles 15 in a direction intersecting the nozzle axis direction differs between when the head 3 is in a predetermined first printing position and when the head 3 is in a second printing position in which the rotation angle about a predetermined rotation axis X parallel to the nozzle axis direction forms a predetermined angle θ with respect to the first printing position. In each printing position, droplets of liquid are ejected from the nozzles 15. This allows the device 1 to perform printing processes at different printing resolutions when using the same head 3.

[0012] 1 includes, as an example, a head unit 2, a platen 5, a transport unit 6, a liquid tank 7, a control unit 8, a casing 10, an arm 11 that supports the head unit 2, and a plurality of heads 3. The system of the device 1 may be another system, such as a serial head system.

[0013] The head unit 2 includes a plurality of heads 3 and a holder 4 that integrally supports the plurality of heads 3. As an example, the holder 4 extends in a direction P2 perpendicular to the transport direction P1. In this embodiment, the holder 4 is a plate member, and the plurality of heads 3 are fixed to one plate surface of the holder 4. The plurality of heads 3 are arranged on the holder 4 with their side surfaces 3b (see FIG. 2) in surface contact with each other. Note that the head unit 2 does not necessarily have to include the holder 4. In this case, the head unit 2 may be directly fixed to the device 1 with the plurality of heads 3 connected to each other.

[0014] The platen 5 is a plate member with a flat upper surface, and is arranged opposite the head unit 2. The dimension of the platen 5 in the orthogonal direction P2 is longer than that of the head unit 2. As a result, the platen 5 is arranged so that the entire landing area of ​​droplets ejected from the multiple nozzles 15 of the head 3 is located within the upper surface area of ​​the platen 5. The platen 5 supports, on its upper surface, the recording medium M that is transported along a predetermined transport direction P1. This defines the distance between the head unit 2 and the recording medium M.

[0015] The transport section 6 has two pairs of transport rollers 12 and 13, and a transport motor. One of the pairs of transport rollers, 12, is disposed upstream of the platen 5 in the transport direction P1. The transport roller pair 12 includes a vertical pair of a drive roller and a driven roller. The drive roller is driven by the transport motor, and holds the recording medium M between itself and the driven roller, and transports the recording medium M downstream in the transport direction P1 onto the platen 5.

[0016] The other pair of conveying rollers 13 is disposed downstream in the conveying direction P1 with respect to the platen 5. The pair of conveying rollers 13 includes a vertical pair of a drive roller and a driven roller. The drive roller is driven by a conveying motor, and sandwiches the recording medium M between itself and the driven roller, and conveys the recording medium M from the platen 5 downstream in the conveying direction P1.

[0017] The multiple liquid tanks 7 store liquid to be supplied to the multiple heads 3. The device 1 of this embodiment includes multiple liquid tanks 7, the number of which corresponds to the type of liquid. As an example of the multiple liquid tanks 7, the device 1 of this embodiment includes a first tank 7A that stores ink of a first color and a second tank 7B that stores ink of a second color. The color of the ink can be set appropriately. For example, two colors can be selected from black, blue, and red. The multiple liquid tanks 7 are connected to the multiple heads 3 by supply tubes 14. The liquid stored in the multiple liquid tanks 7 is supplied to the heads 3 via the supply tubes 14.

[0018] The control unit 8 controls the operation of the drive elements of each unit included in the device 1. For example, when the control unit 8 receives an external command to execute a print job, it causes the conveying unit 6 to convey the recording medium M onto the platen 5. When the recording medium M reaches a predetermined position on the platen 5, liquid is ejected from each head 3 based on image data specified by the print job, forming an image on the recording medium M. In this way, the control unit 8 executes the printing process. The recording medium M on which the image has been formed is conveyed by the conveying unit 6 and discharged from the device 1.

[0019] The casing 10 houses the liquid tank 7 and the control unit 8. The arm 11 extends from the casing 10 and supports the head unit 2. A holder 4 for the head unit 2 is detachably attached to the arm 11. The arm 11 of this embodiment supports the head unit 2 so that it can rotate about a rotation axis X that is parallel to the nozzle axis direction of the multiple nozzles 15 of the head 3. As a result, as shown in FIG. 1, the device 1 of this embodiment is configured so that the arrangement density of the multiple nozzles 15 in a direction intersecting the nozzle axis direction differs between a first printing position and a second printing position that forms a predetermined angle θ with respect to the first printing position about the rotation axis X (see FIGS. 3 and 5).

[0020] 1 shows the relative positional relationship between the head unit 2 in the first printing attitude and an imaginary line Q1 that passes through the axial center position O of the rotation axis X and extends in the transport direction P1, and also shows the relative positional relationship between the head unit 2 in the second printing attitude and an imaginary line Q2 that forms a predetermined angle θ with the imaginary line Q1 around the rotation axis X. In this embodiment, the predetermined angle θ is 30°. As an example, the rotation axis X extends perpendicular to the plane including the upper surface of the platen 5, but is not limited to this.

[0021] [Head configuration] Fig. 2 is a plan view of the head 3 in a first printing position, and Fig. 3 is a partially enlarged view of the head 3 in the first printing position of Fig. 2. Fig. 4 is a plan view of the head 3 in a second printing position, and Fig. 5 is a partially enlarged view of the head 3 in the second printing position of Fig. 4. Figs. 3 and 5 show the arrangement of the multiple nozzles 15 as viewed from the nozzle axis direction, and each shows single imaginary parallel lines L2, N2, and M2. For the sake of explanation, in Figs. 2 to 5, the grid pattern F is shown with imaginary lines, but in reality, no imaginary lines exist.

[0022] As shown in FIGS. 2 and 4 , the head 3 is a head for the liquid ejection device 1 and includes a plurality of nozzles 15. The head 3 has a regular hexagonal nozzle surface 3a on which nozzle groups 16 are arranged, as viewed from the nozzle axis direction of the plurality of nozzles 15, and six side surfaces 3b adjacent to the six sides of the nozzle surface 3a. The head 3 of this embodiment is, as an example, detachably attached to the holder 4 by a fastening member. The nozzle groups 16 of this embodiment include a lattice-arranged nozzle group 17 in which the plurality of nozzles 15 are arranged in a lattice pattern F, with equilateral triangles as lattice units G, as viewed from the nozzle axis direction. In this embodiment, as an example, the plurality of nozzles 15 are arranged on three vertices of the equilateral triangle of the lattice unit G. The nozzle group 16 of this embodiment includes only the lattice-arranged nozzle group 17. Each nozzle 15 has a circular opening, and the center of the nozzle 15 is located at the radial center of the opening.

[0023] 3, in this embodiment, the first printing posture is a posture in which one side of the equilateral triangle that forms the lattice unit G is parallel to the transport direction P1. Also, as shown in FIG. 5, in this embodiment, the second printing posture is a posture in which one side of the equilateral triangle that forms the lattice unit G is perpendicular to the transport direction P1.

[0024] In the second printing posture of this embodiment, the rotation angle differs by 30° from the first printing posture, and therefore the arrangement density of the multiple nozzles 15 differs between the first printing posture and the second printing posture by approximately 1.7 times (√3 times). Specifically, the nozzle arrangement density in the second printing posture is approximately 1.7 times (√3 times) higher than the nozzle arrangement density in the first printing posture. As a result, in the device 1, while using the head 3 having the same grid-arranged nozzle group 17, it is possible to perform printing processing in the second printing posture with a print resolution that is approximately 1.7 times (√3 times) higher in accuracy than in the first printing posture.

[0025] FIG. 3 shows a pitch D1 in the orthogonal direction P2 of the nozzles 15 that eject a first color liquid in the first printing posture, and a pitch D2 in the orthogonal direction P2 of the nozzles 15 that eject a second color liquid in the first printing posture. The pitches D1 and D2 are the same value. FIG. 5 shows a pitch D3 in the orthogonal direction P2 of the nozzles 15 that eject a first color liquid in the second printing posture, and a pitch D4 in the orthogonal direction P2 of the nozzles 15 that eject a second color liquid in the second printing posture. The pitches D3 and D4 are the same value. In the device 1 of this embodiment, the arrangement density of the multiple nozzles 15 is the same in a printing posture in which the rotation angle is 60° with respect to the first printing posture.

[0026] Also, as shown in Figures 3 and 5, when the device 1 defines three nozzles 15, among the multiple nozzles 15, that are arranged at positions corresponding to the vertices of an equilateral triangle in a lattice unit G as a first nozzle 15A, a second nozzle 15B, and a third nozzle 15C, the opening centers of all of the first nozzles 15A and all of the second nozzles 15B are located on a first virtual line L1 that passes through the opening centers of the closest first nozzle 15A and second nozzle 15B, and on multiple first virtual parallel lines L2 that are parallel to the first virtual line L1.

[0027] The centers of the openings of all the second nozzles 15B and all the third nozzles 15C are located on a second virtual line N1 passing through the centers of the openings of the closest second nozzles 15B and third nozzles 15C and on multiple second virtual parallel lines N2 parallel to the second virtual line N1. The centers of the openings of all the third nozzles 15C and all the first nozzles 15A are located on a third virtual line M1 passing through the centers of the openings of the closest third nozzles 15C and first nozzles 15A and on multiple third virtual parallel lines M2 parallel to the third virtual line M1. The line pitches of the first, second, and third virtual lines L1, N1, and M1 and the multiple first, second, and third virtual parallel lines L2, N2, and M3 are the same value.

[0028] In this way, in the device 1, by setting the positions of the multiple nozzles 15, it is possible to prevent the nozzle spacing from becoming uneven in the transport direction P1 and the perpendicular direction P2 in both the first printing attitude and the second printing attitude, thereby enabling printing processing of stable quality.

[0029] 3 and 5, in the grid pattern F, grid units G with two different orientations are alternately arranged. The first to third nozzles 15A, 15B, and 15C described above refer to three nozzles 15 arranged in grid units G with the same orientation included in the grid pattern F. The nozzles 15 arranged on a specific line, which is one of lines L1, L2, N1, N2, M1, and M2, are assigned different symbols in adjacent grid units G with the same orientation along the specific line. As shown in FIG. 3, for example, one nozzle 15 shared by two adjacent grid units G1 and G2 with the same orientation along a first virtual line L1 in the grid unit G corresponds to the second nozzle 15B in the grid unit G1 and the first nozzle 15A in the lattice unit G2.

[0030] The nozzle group 16 arranged on the nozzle surface 3a may include at least one unused nozzle 15. In this case, narrowing the pitch between active nozzles increases the nozzle arrangement density in both the first printing position and the second printing position, thereby improving print resolution. Widening the pitch between active nozzles decreases the nozzle arrangement density in both the first printing position and the second printing position, thereby reducing print resolution.

[0031] Also, for example, if at least one flow path (e.g., a manifold) for liquid supplied to the plurality of nozzles 15 is disposed inside the head 3, the plurality of nozzles 15 disposed in an area that overlaps with the flow path when viewed from the nozzle axis direction may be set as an unused nozzle. This makes it possible to avoid, for example, interference between the liquid supply path connected to the nozzles 15 disposed in that area and the flow path. Also, for example, if the nozzle group 16 includes a plurality of nozzle rows arranged parallel to the longitudinal direction of the manifold, at least one nozzle 15 belonging to the plurality of nozzle rows that overlaps with the manifold may be set as an unused nozzle.

[0032] [Method of manufacturing a liquid ejection device] A manufacturing method for the device 1 of the present disclosure will be described below in relation to the arrangement of the multiple heads 3. This manufacturing method is a method for manufacturing a device 1 equipped with three or more multiple heads 3, each having a nozzle group 16 including a plurality of nozzles 15 that eject liquid onto the surface of the recording medium M. FIG. 6 is a schematic diagram showing how multiple heads are combined and arranged. As an example, FIG. 6 shows a three-stage state diagram (FIG. 6(a), FIG. 6(b), FIG. 6(c)) showing how five heads 3A to 5E are combined and arranged.

[0033] 6(a), in this manufacturing method, first, a first head 3A, a second head 3B, and a third head 3C are prepared as multiple heads 3. Each head 3A has a hexagonal nozzle surface 3a on which nozzle groups 16 are arranged when viewed from the nozzle axis direction of the multiple nozzles 15, and six side surfaces 3b adjacent to the six sides of the nozzle surface 3a. Second, the first head 3A and the second head 3B are arranged so that one side surface 3b of the first head 3A and one side surface 3b of the second head 3B are in surface contact with each other.

[0034] Thirdly, after arranging the first head 3A and the second head 3B, the third head 3C is arranged so that another side surface 3b of the arranged first head 3A and another side surface 3b of the arranged second head 3B are in surface contact with two adjacent side surfaces 3b of the third head 3C.

[0035] Next, as shown in Fig. 6(b), the fourth head 3D is arranged so that one side surface 3b of each of any two heads among the arranged first to third heads 3A to 3C is in surface contact with two adjacent side surfaces 3b of the fourth head 3D. In Fig. 6(b), the other side surface 3b of the arranged first head 3A and the other side surface 3b of the arranged third head 3C are in surface contact with the two adjacent side surfaces 3b of the fourth head 3D.

[0036] Next, as shown in Figure 6(c), the fifth head 3E is positioned so that one side surface 3b of each of any two heads among the first to fourth heads 3A to 3D is in surface contact with two adjacent side surfaces 3b of the fifth head 3E. In Figure 6(c), the other side surface 3b of the third head 3C and the other side surface 3b of the fourth head 3D are in surface contact with two adjacent side surfaces 3b of the fifth head 3E. Note that when placing the sixth and subsequent heads 3, they are also positioned in the same manner as the third head 3C to the fifth head 3E.

[0037] According to the above manufacturing method, even when manufacturing a device 1 including a plurality of heads 3, misalignment between the heads 3 can be easily prevented by arranging the heads 3 so that one side surface 3b of each head is in surface contact with each other. Therefore, by including a plurality of heads 3 arranged with high precision, a device 1 with excellent printing performance can be manufactured. Note that when the side surfaces 3b of the heads 3 are in surface contact with each other, it is desirable, for example, that the entire surfaces of the side surfaces 3b be in surface contact with each other.

[0038] As described above, the head 3 of this embodiment has, when viewed from the nozzle axis direction of the multiple nozzles 15, a nozzle surface 3a on which the nozzle groups 16 are arranged, and six side surfaces 3b adjacent to the six sides of the nozzle surface 3a, and when attached to the device 1, the nozzle groups 16 are configured so that the arrangement density of the multiple nozzles 15 in the intersecting direction intersecting the nozzle axis direction differs when the head 3 is in a predetermined first printing posture and when it is in a second printing posture in which the rotation angle around a predetermined rotation axis X parallel to the nozzle axis direction forms a predetermined angle θ with respect to the first printing posture.

[0039] According to the above configuration, when printing using the same head 3, printing processes can be performed in printing postures with different arrangement densities of the multiple nozzles 15 of the head 3, allowing printing processes to be performed at different print resolutions. Furthermore, because the head 3 is formed in a hexagonal prism shape, when printing using multiple heads 3, it is easy to prevent misalignment between the heads 3 by, for example, arranging the heads 3 so that one side surface 3b of each head is in surface contact with each other.

[0040] Furthermore, in the head 3 of this embodiment, when viewed from the nozzle axis direction, the nozzle group 16 includes a grid-arranged nozzle group 17 in which a plurality of nozzles 15 are arranged in a grid pattern F with equilateral triangles as grid units G. This allows printing processes to be performed at different print resolutions using the grid-arranged nozzle group 17.

[0041] In the device 1 of this embodiment, the predetermined angle θ is 30°, and the arrangement density of the multiple nozzles 15 is the same in a printing position where the rotation angle is 60° relative to the first printing position. This allows printing to be performed at a printing resolution that is approximately 1.7 times higher using the grid-arranged nozzle group 17. Furthermore, it is easy to switch between the first printing position and the second printing position.

[0042] Furthermore, the nozzle group 16 of this embodiment includes only the grid-arranged nozzle group 17. This allows printing processes to be performed at different print resolutions using all of the nozzles 15 of the head 3. Furthermore, since it is no longer necessary to form any nozzle groups other than the grid-arranged nozzle group 17 in the head 3, the manufacturing efficiency of the head 3 can be improved.

[0043] Furthermore, in this embodiment, when the three nozzles 15 arranged at positions corresponding to the vertices of an equilateral triangle in the lattice unit G are designated as a first nozzle 15A, a second nozzle 15B, and a third nozzle 15C, the centers of the openings of all of the first nozzles 15A and all of the second nozzles 15B are located on a first virtual line L1 passing through the centers of the openings of the closest first nozzle 15A and second nozzle 15B and on a plurality of first virtual parallel lines L2, the centers of the openings of all of the second nozzles 15B and all of the third nozzles 15C are located on the second virtual line N1 and a plurality of second virtual parallel lines N2, and the centers of the openings of all of the third nozzles 15C and all of the first nozzles 15A are located on a third virtual line M1 and a plurality of third virtual parallel lines M2. The first, second and third imaginary lines L1, N1 and M1 and the first, second and third imaginary parallel lines L2, N2 and M3 have the same line pitch.

[0044] According to this configuration, even if the printing attitude of the head 3 changes by 30°, it is possible to change the printing resolution while preventing misalignment between the multiple nozzles 15, thereby enabling highly accurate printing processing.

[0045] The device 1 of this embodiment also includes a transport unit 6 that transports the recording medium M in a predetermined transport direction P1, which is a direction perpendicular to the nozzle axis direction. The first printing posture is a posture in which any of the first virtual line L1 and the multiple first virtual parallel lines L2, the second virtual line N1 and the multiple second virtual parallel lines N2, or the third virtual line M1 and the multiple third virtual parallel lines M2 is parallel to the transport direction P1. The second printing posture is a posture in which any of the first virtual line L1 and the multiple first virtual parallel lines L2, the second virtual line N1 and the multiple second virtual parallel lines N2, or the third virtual line M1 and the multiple third virtual parallel lines M2 is perpendicular to the transport direction P1.

[0046] According to the above configuration, based on the transport direction P1 of the recording medium M, one of the first printing posture and the second printing posture can be set as a printing posture with low resolution, and the other posture can be set as a printing posture with high resolution.

[0047] Furthermore, the manufacturing method of the device 1 of this embodiment is a manufacturing method of the device 1 that includes three or more heads 3, each having a nozzle group 16 including a plurality of nozzles 15 that eject liquid onto the surface of the recording medium M, and the heads 3 are prepared as follows: a first head 3A, a second head 3B, and a third head 3C, each having a hexagonal nozzle surface 3a on which the nozzle groups 16 are arranged when viewed from the nozzle axis direction of the plurality of nozzles 15, and six side surfaces 3b adjacent to the six sides of the nozzle surface 3a; the first head 3A and the second head 3B are arranged so that one side surface 3b of the first head 3A and one side surface 3b of the second head 3B are in surface contact with each other side surface 3b; and after arranging the first head 3A and the second head 3B, the third head 3C is arranged so that the other side surface 3b of the arranged first head 3A and the other side surface 3b of the arranged second head 3B are in surface contact with two adjacent side surfaces 3b of the third head 3C.

[0048] This manufacturing method makes it easy to prevent misalignment between the heads 3, even when manufacturing the device 1 using multiple heads 3. This makes it possible to manufacture the device 1 equipped with multiple heads 3 arranged with high precision. Note that the nozzle group 16 of the head 3 may include nozzles 15 that are not arranged at the vertices of the triangles that are the lattice units G of the lattice pattern F. [Industrial Applicability]

[0049] The present disclosure can be applied to a liquid ejection device equipped with a head that ejects a liquid such as ink onto a recording medium. [Explanation of symbols]

[0050] L1 First virtual line L2 First imaginary parallel line M1 Second virtual line M2 Second imaginary parallel line N1 3rd Virtual Line N2 Third imaginary parallel line M Recording medium P Conveying direction X rotation axis 1 Liquid discharge device 2. Head unit (liquid ejection device head unit) 3, 3A~3E head 3a Nozzle surface 3b side 6. Conveyor 15 nozzles 16 nozzle groups 17 Grid-arranged nozzle group

Claims

1. A head for a liquid ejection device, the head having a nozzle group including a plurality of nozzles that eject liquid onto a surface of a recording medium, a nozzle surface having a regular hexagonal shape in which the nozzle group is arranged when viewed from the nozzle axis direction of the plurality of nozzles, and six side surfaces adjacent to six sides of the nozzle surface; and A head for a liquid ejection device, wherein when the head is attached to the liquid ejection device, the nozzle group is configured so that the arrangement density of the multiple nozzles in a direction intersecting the nozzle axis direction differs when the head is in a predetermined first printing position and when the head is in a second printing position in which the rotation angle around a predetermined rotation axis parallel to the nozzle axis direction forms a predetermined angle with respect to the first printing position.

2. The liquid ejection head according to claim 1 , wherein the nozzle groups include a lattice-arranged nozzle group in which the plurality of nozzles are arranged in a lattice pattern with equilateral triangles as lattice units, as viewed in the nozzle axis direction.

3. The predetermined angle is 30°. The liquid ejection device head according to claim 2 , wherein the nozzles are arranged at the same density in a printing position where the rotation angle is 60° relative to the first printing position.

4. The liquid ejection head according to claim 3 , wherein the nozzle group includes only the lattice-arranged nozzle group.

5. When three nozzles among the plurality of nozzles arranged at positions corresponding to the vertices of the equilateral triangle in the lattice unit are defined as a first nozzle, a second nozzle, and a third nozzle, the centers of the openings of all of the first nozzles and all of the second nozzles are located on a first virtual line passing through the centers of the openings of the first nozzles and the second nozzles that are closest to each other, and on a plurality of first virtual parallel lines that are parallel to the first virtual line; the centers of the openings of all the second nozzles and all the third nozzles are located on a second virtual line passing through the centers of the openings of the second nozzles and the third nozzles that are closest to each other, and on a plurality of second virtual parallel lines that are parallel to the second virtual line; the centers of the openings of all of the third nozzles and all of the first nozzles are located on a third virtual line passing through the centers of the openings of the third nozzles and the first nozzles that are closest to each other, and on a plurality of third virtual parallel lines that are parallel to the third virtual line; 5. The liquid ejection head according to claim 4, wherein the first, second, and third virtual lines and the plurality of first, second, and third virtual parallel lines have the same line pitch.

6. a conveying unit configured to convey the recording medium in a predetermined conveying direction that is a direction perpendicular to the nozzle axis direction, the first printing posture is a posture in which any one of the first virtual line and the plurality of first virtual parallel lines, the second virtual line and the plurality of second virtual parallel lines, or the third virtual line and the plurality of third virtual parallel lines is parallel to the transport direction, 6. A head for a liquid ejection device according to claim 5, wherein the second printing posture is a posture in which any one of the first virtual line and the plurality of first virtual parallel lines, the second virtual line and the plurality of second virtual parallel lines, or the third virtual line and the plurality of third virtual parallel lines is perpendicular to the transport direction.

7. At least three heads according to any one of claims 1 to 6 are provided; A head unit for a liquid ejection device, wherein, when viewed from the nozzle axis direction, each of the three heads is arranged so that two adjacent side surfaces are in surface contact with one of the side surfaces of each of the remaining two heads among the three heads.

8. A liquid ejection device comprising at least one head according to any one of claims 1 to 6.

9. A method for manufacturing a liquid ejection device having three or more heads, each head having a nozzle group including a plurality of nozzles that eject liquid onto a surface of a recording medium, comprising: As the plurality of heads, a first head, a second head, and a third head are prepared, each having a hexagonal nozzle surface on which the nozzle groups are arranged when viewed from a nozzle axis direction of the plurality of nozzles, and six side surfaces adjacent to six sides of the nozzle surface; the first head and the second head are arranged so that one side surface of the first head and one side surface of the second head are in surface contact with each other; A method for manufacturing a liquid ejection device, comprising: arranging the first head and the second head, and then arranging the third head so that another side of the arranged first head and another side of the arranged second head are in surface contact with two adjacent side surfaces of the third head.

Images