Inkjet printing apparatus and printing method

Abstract

To suppress the number of components on an inkjet printing device that can arbitrarily adjust a pitch of multiple nozzles.SOLUTION: An inkjet printing device includes: a first line head unit including a first base member and multiple first inkjet heads which are fitted to the first base member so as to be rotatable about an axis line orthogonal to a printing surface relative to the first base member and in which multiple nozzles are arranged linearly; and a line head unit rotary mechanism part for rotating the first line head unit about the axis line orthogonal to the printing surface relative to the printing surface.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an inkjet printing apparatus and a printing method. [Background technology]

[0002] In recent years, a method for manufacturing devices using an inkjet printing apparatus has been attracting attention. An inkjet printing apparatus ejects droplets from multiple nozzles while controlling the positional relationship between the nozzles and the target areas of the printing object. Some printing objects, such as display devices, have target areas of the printing object arranged at a fixed pitch.

[0003] In this case, a coating method has been disclosed in which an inkjet head with multiple nozzles arranged at a fixed pitch is rotated around an axis perpendicular to the surface of the printing object, thereby matching the pitch of the impacted droplets with the pitch of the coating target portion of the coating object (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4971560 Summary of the Invention [Problem to be solved by the invention]

[0005] However, as display panels have become larger in recent years, the number of inkjet heads used has increased. With the conventional method of equipping each inkjet head with two drive mechanisms, the number of drive axes has increased dramatically, which has become a problem in terms of cost and facility management. The present invention has been made in view of the above-mentioned problems, and aims to provide a method for manufacturing a nozzle array that can be easily arranged with a desired pitch. The present invention aims to reduce the number of parts in an inkjet printing device that can be freely adjusted. [Means for solving the problem]

[0006] The inkjet printing apparatus according to one aspect of the present invention includes a first base member, and a printing surface, the first base member being rotated about an axis perpendicular to the printing surface. In one body The ink jet head includes a first line head unit that is attached to the first base member so as to be rotatable relative to the first base member and that has a plurality of first inkjet heads that apply the same type of ink and have a plurality of nozzles arranged in a line, and a line head unit rotation mechanism that rotates the first line head unit relative to the printing surface around an axis perpendicular to the printing surface.

[0007] A printing method according to one aspect of the present invention includes: a first base member; and a printing surface of the first base member, the printing surface being rotated about an axis perpendicular to the axis of the first base member. Integral a line head unit rotation mechanism that rotates the first line head unit relative to the printing surface about an axis perpendicular to the printing surface, the first line head unit being attached to the first base member so as to be relatively rotatable, the first inkjet heads having a plurality of first inkjet heads that apply the same type of ink and each having a plurality of nozzles arranged in a line; and a line head unit rotation mechanism that rotates the first line head unit relative to the printing surface about an axis perpendicular to the printing surface, the method including: rotating the first inkjet heads so that a distance between the plurality of nozzles in a direction perpendicular to the direction in which the printing surface moves corresponds to a predetermined resolution; In one body a step of rotating the first line head unit by the line head unit rotation mechanism so that the distance between two adjacent first inkjet heads among the plurality of first inkjet heads in a direction perpendicular to the direction in which the printing surface moves is a distance corresponding to the predetermined resolution; and a step of moving the printing surface relative to the first line head unit and ejecting ink from the plurality of nozzles toward the printing surface to perform printing. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a plan view of a display panel. [Figure 2] 1 is a schematic plan view of an inkjet printing apparatus according to a first embodiment of the present invention. [Figure 3] 3 is a schematic plan view showing a line head unit and a line head unit Φ rotation mechanism mounted on the inkjet printing apparatus shown in FIG. 2. FIG. [Figure 4] 3 is a schematic plan view showing a state in which a line head unit is rotated in the inkjet printing apparatus shown in FIG. 2.

[0023] FIG. [Figure 5] 3 is a plan view showing the relationship between nozzle positions and print target positions when printing a display panel with a first resolution in the inkjet printing device shown in FIG. 2. FIG. [Figure 6] 3 is a plan view showing the relationship between nozzle positions and print target positions when printing a display panel with second resolution in the inkjet printing device shown in FIG. 2. FIG. [Figure 7] 10 is a plan view showing a case where the nozzle position does not match the print target position when printing a display panel with a third resolution in the inkjet printing device shown in FIG. 2. FIG. [Figure 8] 3 is a plan view showing the relationship between nozzle positions and print target positions when printing a display panel with a third resolution in the inkjet printing apparatus of the first embodiment shown in FIG. 2. FIG. [Figure 9] FIG. 10 is a schematic plan view of a line head unit mounted on an inkjet printing apparatus according to a second embodiment of the present invention. [Figure 10] 10 is a plan view showing a state in which the tilt of one line head unit mounted on the inkjet printing apparatus shown in FIG. 9 has been adjusted to match the first definition. FIG. [Figure 11] 10 is a plan view showing a dual line head unit in which two line heads are combined so as to be able to perform printing at a first resolution in the inkjet printing apparatus shown in FIG. 9. FIG. [Figure 12] 10 is a plan view showing a state in which the position of the dual line head unit has been adjusted so as to perform printing at a fourth resolution in the inkjet printing apparatus shown in FIG. 9. FIG. [Figure 13] FIG. 10 is a schematic plan view of an inkjet printing apparatus according to a second embodiment. [Figure 14] FIG. 10 is a schematic plan view showing a line head mounted on an inkjet printing apparatus according to a third embodiment of the present invention and a rotation mechanism for rotating the line head. [Figure 15A] FIG. 2 is a plan view showing nozzle positions of an inkjet head mounted on a line head according to the first to third embodiments. [Figure 15B] 10 is a plan view showing the positional deviation in the Y direction between the nozzles in row A and the nozzles in row B when the inkjet head mounted on the line head unit is tilted at an angle θ. FIG. [Figure 16A] FIG. 2 is a plan view showing nozzle positions of an inkjet head with 800 nozzles in one row mounted on a line head unit. [Figure 16B] FIG. 10 is a plan view showing the Y-direction positional deviation between nozzles in row A and nozzles in row B when an inkjet head having 800 nozzles formed in one row, which is mounted on a line head unit according to any one of the first to third embodiments, is tilted at an angle θ. [Figure 17A] 10 is a graph showing the relationship between the resolution of a display panel and the rotation angle of a line head unit (low resolution side) in the first and third embodiments. [Figure 17B] 10 is a graph (low definition side) showing the relationship between the resolution of a display panel and the number of used nozzles of an inkjet head in a line head unit in the first and third embodiments. [Figure 17C] 10 is a graph (low definition side) showing the relationship between the resolution of the display panel and the amount of deviation of the nozzle positions of the B row nozzles in the first and third embodiments. [Figure 18A] 10 is a graph (high definition side) showing the relationship between the resolution of a display panel and the rotation angle of a line head unit in the first and third embodiments. [Figure 18B] 10 is a graph (high definition side) showing the relationship between the resolution of a display panel and the number of nozzles in use in the first and third embodiments. [Figure 18C] 10 is a graph (high definition side) showing the relationship between the resolution of the display panel and the amount of deviation of the nozzle positions of the B row nozzles in the first and third embodiments. [Figure 19A] 10 is a graph (low definition side) showing the relationship between the resolution of a display panel and the rotation angle of a line head unit in the second embodiment. [Figure 19B] 10 is a graph (low definition side) showing the relationship between the resolution of a display panel and the number of used nozzles of an inkjet head in a sub-line head unit in the second embodiment. [Figure 19C] 10 is a graph (low definition side) showing the relationship between the resolution of the display panel and the amount of displacement of the nozzle positions of the nozzles in row B in the second embodiment. [Figure 20A] 10 is a graph (high definition side) showing the relationship between the resolution of a display panel and the corresponding rotation angle of a line head in the second embodiment. [Figure 20B] 10 is a graph (high definition side) showing the relationship between the resolution of a display panel and the number of used nozzles of inkjet heads in sub-line heads in the second embodiment. [Figure 20C] 10 is a graph (high definition side) showing the relationship between the resolution of the display panel and the amount of displacement of the nozzle positions of the nozzles in row B in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] The conventional method will be described with reference to Figures 7 and 12 of Patent Document 1. Figure 7 of Patent Document 1 is a diagram showing the bottom surface of an inkjet head unit, and Figure 12 of Patent Document 1 is a diagram showing an object to be printed.

[0010] As shown in FIG. 7 of Patent Document 1, the inkjet head unit includes a head mounting base 120, reference surfaces 120a and 120b, R inkjet heads 121a to 121h, G inkjet heads 122a to 122h, and B inkjet heads 123a to 123h.

[0011] Each of the R inkjet heads 121a to 121h has 200 nozzles formed linearly at a constant pitch. For example, in the R inkjet head 121a, nozzle 121a1 indicates the first nozzle, and nozzle 121a200 indicates the 200th nozzle. This also applies to the G inkjet heads 122a to 122h and the B inkjet heads 123a to 123h. Each inkjet head is equipped with a rotation drive mechanism in the θ direction and a translation drive mechanism in the nozzle row direction.

[0012] As shown in FIG. 12 of Patent Document 1, on the printing object, red colored pixels 100a, blue colored pixels 100b, and green colored pixels 100c are arranged in this order along the X direction, and the pitch between the same colored pixels is uniformly set at 190.5 μm.

[0013] Next, a conventional method for applying ink droplets onto the above-mentioned printing object from the nozzles of an inkjet head will be described.

[0014] The nozzles at both ends of each of the inkjet heads 121a-121h, 122a-122h, and 123a-123h mounted on the inkjet head unit, for example, the pitch in the X direction between nozzle 121a1 and nozzle 121a200 of inkjet head 121a, is measured using a nozzle hole position measurement camera. Next, based on the measurement results of the nozzle hole position measurement camera, the rotational position of R inkjet head 121a is adjusted using a rotation drive mechanism so that the pitch in the X direction between nozzle 121a1 and nozzle 121a200 is 190.5 μm. This is performed for all of the inkjet heads 121a-121h, 122a-122h, and 123a-123h.

[0015] Furthermore, for R inkjet heads 121a to 121h adjacent to each other in the X direction, the positions of inkjet heads 121a to 121h are adjusted by the translation drive mechanism so that the pitch in the X direction between the first nozzles, for example, nozzle 121a1 and nozzle 121b1, is 38.100 mm. This is performed for all inkjet heads 121a to 121h, 122a to 122h, and 123a to 123h.

[0016] Next, the positions of inkjet heads 121a, 122a, and 123a, which are adjacent to each other in the Y direction, are adjusted by the translation drive mechanism so that the pitch in the X direction of nozzles 121a1, 122a1, and 123a1 becomes 63.5 μm, which is one-third of the pixel pitch. This is performed for all inkjet heads 121a to 121h, 122a to 122h, and 123a to 123h.

[0017] By adjusting the positions of all inkjet heads 121a to 121h, 122a to 122h, and 123a to 123h in this manner, the nozzle pitch in the X direction of all inkjet heads 121a to 121h, 122a to 122h, and 123a to 123h is matched with the pixel pitch in the X direction of the printing object.

[0018] Next, after aligning the printing object in the X, Y, and θ directions, the printing object is scanned below the inkjet head unit, and ink is ejected from the inkjet heads 121a-121h, 122a-122h, and 123a-123h at the required timing, thereby enabling ink to be applied to the printing object with high precision.

[0019] However, in recent years, display panels have become larger, and there is a growing demand for coating the entire width of the substrate in a single scan to prevent uneven drying of the coating.In addition, the number of inkjet heads used is increasing, and with the conventional method of equipping each inkjet head with two drive mechanisms, the number of drive axes has increased dramatically, which has become a problem in terms of cost and facility management.

[0020] The present invention has been made in view of the above problems, and has as its object to reduce the number of parts in an inkjet printing device that can arbitrarily adjust the pitch of a plurality of nozzles.

[0021] In order to achieve the above object, an inkjet printing device in one aspect of the present invention comprises a first base member, a first line head unit attached to the first base member so as to be rotatable relative to the first base member about an axis perpendicular to the printing surface, and comprising a plurality of first inkjet heads each having a plurality of nozzles arranged in a straight line, and a line head unit rotation mechanism that rotates the first line head unit relative to the printing surface about an axis perpendicular to the printing surface.

[0022] In one aspect of the present invention, a printing method uses an inkjet printing device including: a first base member; a first line head unit attached to the first base member so as to be rotatable relative to the first base member about an axis perpendicular to the printing surface, the first line head unit including a plurality of first inkjet heads having a plurality of nozzles arranged in a line; and a line head unit rotation mechanism that rotates the first line head unit relative to the printing surface about the axis perpendicular to the printing surface, the method including the steps of: rotating the plurality of first inkjet heads so that the distance between the plurality of nozzles in a direction perpendicular to the direction in which the printing surface moves corresponds to a predetermined resolution; rotating the first line head unit by the line head unit rotation mechanism so that the distance between two adjacent first inkjet heads among the plurality of first inkjet heads in the direction perpendicular to the direction in which the printing surface moves corresponds to the predetermined resolution; and moving the printing surface relative to the first line head unit and ejecting ink from the plurality of nozzles toward the printing surface to print.

[0023] According to the inkjet printing apparatus and printing method of the present invention, the number of parts can be reduced in an inkjet printing apparatus that can arbitrarily adjust the pitch of a plurality of nozzles.

[0024] Hereinafter, a first embodiment of an inkjet printing apparatus 1 of the present invention will be described with reference to the drawings.

[0025] (Embodiment 1) Figure 1 is a plan view of a display panel 2 that is the target of coating by an inkjet printing device 1. As shown in Figure 1, red pixels 3a, blue pixels 3b, and green pixels 3c are repeatedly arranged on a substrate 3, and the pitch (Pp), which corresponds to the distance between pixels of the same color in the Y direction, is constant within the substrate 3. The Y direction is the up-down direction in Figure 1. The plate surface of the substrate 3 is an example of a "printing surface."

[0026] Fig. 2 is a schematic plan view of the inkjet printing apparatus 1 of embodiment 1. Fig. 3 is a schematic plan view of the line head unit 20 mounted on the inkjet printing apparatus 1 of embodiment 1 and the line head unit Φ rotation mechanism 22 that rotates the entire line head unit 20. The line head unit Φ rotation mechanism 22 is an example of a "line head unit rotation mechanism section."

[0027] An overall view of the inkjet printing device 1 will be described using Figure 2, and the line head unit 20 will be described using Figure 3. In each figure, the printing direction is the X direction, and the width direction perpendicular to the printing direction is the Y direction. The printing direction is the same as the direction in which the printing surface moves. In each figure, the front and back sides of the paper will be described as the top and bottom of the inkjet printing device 1.

[0028] <Configuration> As shown in Figure 2, the inkjet printing device 1 includes a base plate 17, a substrate transport stage 12 installed on the base plate 17, head unit support parts 16 installed on both sides of the base plate 17 in the Y direction, and a line head unit 20 mounted on the head unit support part 16 via a line head unit Φ rotation mechanism 22.

[0029] The line head unit 20 is a separate line head unit for each ink to be ejected, for example, for red ink, blue ink, and green ink, and each ink is applied in turn.

[0030] The substrate transfer stage 12 includes an X-axis guide 13 installed on a base plate 17 so as to extend along the X direction, an X-axis slider 9 supported on the X-axis guide 13 so as to be movable along the X direction, and a substrate suction table 11 mounted via a Yα drive mechanism (not shown) installed on the X-axis slider 9. A display panel 2 to be printed can be suction-fixed onto the substrate suction table 11 in a manner parallel to the XY plane.

[0031] The position of the X-axis slider 9 is controlled by an X-axis slider control means (not shown). Specifically, the X-axis slider control means feedback controls the drive amount of an X-axis linear motor 14 that drives the X-axis slider 9 so that the detection result of an X-axis position detection means 15 that detects the position of the X-axis slider 9 coincides with the target position of the X-axis slider 9.

[0032] The Yα drive mechanism (not shown) moves the substrate suction table 11 along the Y direction relative to the X-axis slider 9 and rotates it around an axis perpendicular to the XY plane. Hereinafter, the direction around this axis will be referred to as the α direction. The Yα drive mechanism is controlled by a Yα control means (not shown). The Yα control means controls the Yα drive mechanism based on the target position of the substrate suction table 11 in the Y direction and the target position in the α direction.

[0033] Furthermore, an alignment camera (not shown) is installed on the surface plate 17 to measure the position of the display panel 2 in the X direction, the Y direction, and the α direction.

[0034] As shown in Fig. 3, the line head unit 20 includes a line head base 21 formed in a rectangular shape when viewed from above, multiple inkjet heads 24, a fixed link 23a, and a movable link 23b. The line head base 21 is an example of a "first base member" and a "second base member." The movable link 23b is an example of a "connecting member." The inkjet heads 24 are an example of a "first inkjet head" and a "second inkjet head."

[0035] A first end of each of the inkjet heads 24a to 24j is connected to the fixed link 23a by a link rotation shaft member 23c so as to be rotatable relative to the fixed link 23a about the central axis of the link rotation shaft member 23c. A second end of each of the inkjet heads 24a to 24j is connected to the movable link 23b by a link rotation shaft member 23c so as to be rotatable relative to the fixed link 23a about the central axis of the link rotation shaft member 23c. The fixed link 23a and the movable link 23b are arranged parallel to each other. The inkjet heads 24a to 24j are arranged parallel to each other and at equal intervals. That is, the inkjet heads 24a to 24j, the fixed link 23a, and the movable link 23b constitute a parallel link mechanism 23. The central axis of the link rotation shaft member 23c is perpendicular to the printing surface of the display panel 2 (i.e., the plate surface of the substrate 3).

[0036] The fixed link 23a is fixed to the line head base 21 so that the longitudinal direction of the fixed link 23a is aligned with the longitudinal direction of the line head base 21. The movable link 23b is disposed on the line head base 21 so that the longitudinal direction of the movable link 23b is aligned with the longitudinal direction of the line head base 21 and so as to be movable in parallel relative to the line head base 21.

[0037] Specifically, both ends of the movable link 23b are connected to the θ-axis table 25a via movable link lateral sliding guides 23g. The movable link 23b moves relative to the line head base 21 along a direction perpendicular to the longitudinal direction of the line head base 21 by the movable link lateral sliding guides 23g. The θ-axis table 25a is disposed on the line head base 21 via the θ-axis guide 25g. The θ-axis table 25a moves relative to the line head base 21 along the longitudinal direction of the line head base 21 by the θ-axis guide 25g. The θ-axis table 25a and the θ-axis guide 25g constitute a θ-axis sliding mechanism 25.

[0038] The θ-axis table 25a is connected to a nut (not shown) that fits onto a θ-axis ball screw 26s. The θ-axis ball screw 26s is connected to a θ-axis motor 26m. The θ-axis motor 26m is fixed to the line head base 21 via a θ-axis motor bracket 26b. When the θ-axis motor 26m is driven, the θ-axis table 25a moves along the θ-axis guide 25g. The θ-axis motor 26m, the θ-axis ball screw 26s, and the θ-axis motor bracket 26b constitute the θ-axis drive unit 26.

[0039] Furthermore, the θ-axis table 25a is equipped with a θ-axis position detection unit (not shown) that detects the position of the θ-axis table 25a. The position of the θ-axis table 25a is controlled by a θ-axis position control unit (not shown). Specifically, the θ-axis position control unit feedback-controls the drive amount of the θ-axis motor 26m so that the detection result of the θ-axis position detection unit matches the target position of the θ-axis table 25a. The parallel link mechanism 23, the θ-axis sliding mechanism 25, and the θ-axis drive unit 26 constitute an inkjet head θ rotation mechanism 29. The inkjet head 24 rotates relative to the line head base 21 as the movable link 23b moves in parallel by the inkjet head θ rotation mechanism 29. The angle by which the inkjet head 24 rotates with respect to the X direction is referred to as a first angle θ. The first angle θ is the angle between the X direction and the longitudinal direction of the inkjet head 24. The inkjet head θ rotation mechanism 29 is an example of an "inkjet head rotation mechanism."

[0040] The line head unit Φ rotation mechanism 22 includes a line head Φ rotation shaft member 22c, a Φ axis guide 22g2, a Φ axis table 22t, a rotary slide mechanism 22r, and a Φ axis horizontal slide guide 22g1. The line head Φ rotation shaft member 22c is disposed on the upper surface of one side of the head unit support portion 16, which is installed on both sides of the surface plate 17 in the Y direction, and connects the head unit support portion 16 to a first end of the line head base 21. The line head Φ rotation shaft member 22c rotates the line head base 21 relative to the head unit support portion 16 around the central axis of the line head Φ rotation shaft member 22c, which is perpendicular to the XY plane. The central axis of the Φ rotation shaft member 22c is perpendicular to the printing surface of the display panel 2 (i.e., the plate surface of the substrate 3).

[0041] The Φ-axis guide 22g2 is disposed on the upper surface of the other side of the head unit support 16 and moves the Φ-axis table 22t relative to the head unit support 16 in the X direction. The rotary sliding mechanism 22r is disposed on the upper surface of the Φ-axis table 22t and connects the Φ-axis table 22t to the Φ-axis lateral sliding guide 22g1. The rotary sliding mechanism 22r causes the Φ-axis lateral sliding guide 22g1 to rotate relative to the Φ-axis table 22t around an axis that is perpendicular to the XY plane and passes through the rotary sliding mechanism 22r. A second end of the line head base 21 is connected to the Φ-axis lateral sliding guide 22g1. The second end is located opposite the first end, with the multiple inkjet heads 24 sandwiched between them. The Φ-axis lateral sliding guide 22g1 moves the line head base 21 relative to the rotary sliding mechanism 22r in the direction in which the Φ-axis lateral sliding guide 22g1 extends.

[0042] A φ-axis motor 22m is attached to the upper surface of the other side of the head unit support part 16 via a φ-axis motor bracket 22b. The φ-axis motor 22m is connected to a φ-axis ball screw 22s, and a nut (not shown) engaged with the φ-axis ball screw 22s is connected to a φ-axis table 22t. With this configuration, the φ-axis table 22t moves in the X direction when the φ-axis motor 22m rotates. Meanwhile, the line head unit 20 rotates relatively around the axis of a φ rotating shaft member 22c disposed on one side of the head unit support part 16. That is, the line head unit 20 rotates relatively to the head unit support part 16 by the line head unit φ rotation mechanism 22. The angle by which the line head unit 20 rotates relative to the Y direction is referred to as a second angle Φ. The second angle Φ is the angle between the Y direction and the longitudinal direction of the line head unit 20. FIG. 4 is a schematic plan view of the inkjet printing apparatus 1 of the first embodiment when the inclination of the line head unit 20 is in the state shown in FIG.

[0043] The inkjet printing device 1 also includes an inkjet ejection control unit (not shown) that controls the ejection drive of each nozzle provided in all of the inkjet heads 24 mounted on the line head unit 20. The inkjet ejection control unit is capable of controlling the ejection timing of each nozzle based on the output signal of the X-axis position detection means 15, the angle of the longitudinal direction of the inkjet head 24 relative to the X direction (i.e., the first angle θ), and the angle of the longitudinal direction of the line head unit 20 relative to the Y direction (i.e., the second angle Φ). Each nozzle ejects ink downward.

[0044] 3, the inkjet head 24a is shown with four nozzles 24a1 to 24a4 arranged in a straight line. However, this is a simplified representation of the nozzle arrangement, and in the actual inkjet head 24, as shown in FIG. 15A, 400 nozzles 24aA1 to 24aA400 are arranged at regular intervals along a straight line A. Also, 400 nozzles 24aB1 to 24aB400 are arranged at regular intervals along a straight line B. Line A and line B are arranged parallel to each other. Line A and line B are examples of "nozzle lines."

[0045] <Operation> Next, the printing operation of the inkjet printing apparatus 1 configured as above will be described. (1) First, the operation of adjusting the pitch in the Y direction of all the nozzles arranged in the line head unit 20 to the definition Pd of the display panel 2 to be printed will be described with reference to FIGS.

[0046] FIG. 5 is a plan view illustrating the relationship between the nozzle position and the print target position when printing a display panel 2a having a first resolution Pd in ​​the inkjet printing apparatus 1 of embodiment 1. FIG. 6 is a plan view illustrating the relationship between the nozzle position and the print target position when printing a display panel 2b having a second resolution Pd in ​​the inkjet printing apparatus 1 of embodiment 1. FIG. 7 is a plan view illustrating a case where the nozzle position and the print target position do not match when printing a display panel 2c having a third resolution Pd in ​​the inkjet printing apparatus 1 of embodiment 1. FIG. 8 is a plan view illustrating the relationship between the nozzle position and the print target position when printing a display panel 2c having a third resolution Pd in ​​the inkjet printing apparatus 1 of embodiment 1.

[0047] In Figure 5, Mp is the distance between the central axes of adjacent link rotation shaft members 23c in the fixed link 23a. MpΦ is the distance between Mp in the Y direction, and corresponds to the distance between adjacent inkjet heads 24 in the Y direction. MpΦ is expressed by equation (1). Φ is the second angle.

[0048] MpΦ=Mp×cosΦ Equation (1)

[0049] Furthermore, Np is the distance between adjacent nozzles in any inkjet head 24. θ is the first angle. Hp corresponds to the distance in the Y direction between adjacent nozzles in one inkjet head 24. Hp is expressed by equation (2). Hp is adjusted by changing the first angle θ so that it matches Pp, which corresponds to the distance in the Y direction between nozzles of the same color on the display panel 2. Hp may change by more than twice as much before and after relative rotation of the inkjet head 24 with respect to the line head base 21.

[0050] Hp=Np×sinθ Equation (2)

[0051] Here, in order to make the pitch in the Y direction of all nozzles arranged in the line head unit 20 equal to Hp, it is necessary to satisfy equation (3). To achieve this, the second angle Φ is changed based on equation (1) to adjust MpΦ. n is the number of nozzles required for printing in any inkjet head 24 (details will be described later).

[0052] MpΦ=n×Hp Equation (3)

[0053] Furthermore, the area where ink is ejected onto the moving printing surface (printing width in the Y direction) is denoted by Pw. If the number of nozzles aligned in a line in one inkjet head 24 is denoted by Nn, Pw is expressed by equation (4).

[0054] Pw=Nn×Hp...Equation (4)

[0055] The state of the line head unit 20 shown in Figure 5 indicates that Mp, which corresponds to the distance between the link rotation shaft members 23c, is n times (four times in Figure 3) the pitch (Pp) between the same colors on the display panel 2, and the printing width (Pw) matches Mp.

[0056] 5 is a state in which the pitch in the Y direction of all the nozzles arranged in the line head unit 20 can be made equal and minimum at Hp. In other words, the first angle θ of the inkjet head 24 shown in FIG. 5 is a state in which ink can be applied most precisely in one scan. If the first angle θ of the inkjet head 24 is smaller than the angle shown in FIG. 5, there will be places where the pitch in the Y direction of all the nozzles arranged in the line head unit 20 will be wider than Hp. Therefore, printing cannot be done in one scan, and multiple scans must be repeated to print.

[0057] 2 to 4, only four nozzles are shown for each inkjet head 24 for simplicity's sake. However, the inkjet head 24 actually used in the first to third embodiments has 400 nozzles arranged in each of rows A and B, as shown in FIG. 15A. In this example, the nozzles in row A of the two rows shown in FIG. 15A are used. The first resolution Pd of the display panel 2a shown in FIG. 5 is 440 ppi (pixels per inch). Below, we will explain the case where the display panel 2a is printed using the line head unit 20 in which the inkjet head 24 shown in FIG. 15A is arranged.

[0058] 15A, the inkjet head 24 is set to Np=0.16933333 mm (=169.33333 μm), and as described above, Nn=400. The line head unit 20 is set to Mp=23090.909 μm. Therefore, when the inkjet head θ rotation mechanism 29 is controlled to rotate the inkjet head 24 so that θ=19.93227 degrees, Hp=57.727273 μm (Equation (2)).

[0059] At this time, Mp / Hp=400, and Mp is an integer multiple of Hp. Therefore, by setting the second angle Φ to 0 degrees in equation (1), MpΦ=Mp, and equation (3) is established. Therefore, the line head unit Φ rotation mechanism 22 is controlled to set the second angle Φ to 0 degrees. At this time, n=400.

[0060] Furthermore, at this time, from equation (4), Pw = 23090.90 μm. Therefore, Pw = Mp. Furthermore, since equation (3) holds, the pitch in the Y direction of all the nozzles arranged in the line head unit 20 is the same at Hp.

[0061] When printing is performed on the display panel 2a using the line head unit 20 configured in this way, the pitch (Pp), which corresponds to the distance in the Y direction between the same colors on the display panel 2a, is equal to Hp (i.e., Pp = Hp = 57.72726 μm). Therefore, the resolution Pd of the display panel 2a is 440 ppi according to equation (5), which corresponds to the first resolution Pd.

[0062] Pd=25400 / Pp...Formula (5)

[0063] In this case, there are no nozzles adjacent to each other in the printing direction (X direction). In other words, all nozzles are used for printing. As described above, the inkjet head 24 has 400 nozzles formed therein, so the number of nozzles used for printing in one inkjet head 24 is 400. This is also expressed by n in equation (3). In other words, n indicates the number of nozzles required for printing in one inkjet head 24.

[0064] Next, in this embodiment, a case where a display panel 2b having a second definition Pd is printed using the line head unit 20 will be described with reference to Fig. 6. The second definition Pd is 220 ppi.

[0065] When the resolution Pd is 220 ppi, equation (5) gives Pp = 115.454545 μm. To obtain Hp = Pp, equation (2) sets θ = 42.98588 deg. Furthermore, equation (4) gives Pw = 46181.8 μm, resulting in Pw / Mp = 2. Therefore, Mp / Hp = 200 (= n), which means Mp is an integer multiple of Hp. Therefore, equation (3) is satisfied by setting the second angle Φ = 0 deg. In this case, the Y-direction pitch of all nozzles arranged in the line head unit 20 is equal to Hp. Based on these, the inkjet head θ rotation mechanism 29 is controlled to position the inkjet head 24 so that θ = 42.98588 deg, and the line head unit Φ rotation mechanism 22 is controlled to position the line head unit 20 so that Φ = 0 deg.

[0066] In this case, Pw / Mp=2, so the nozzles of the inkjet heads 24 are positioned adjacent to each other in the printing direction (X direction), as shown in FIG. 6. Therefore, even if one nozzle stops ejecting ink, the malfunction of that nozzle can be compensated for by ejecting ink from the other nozzle. In other words, it is not necessary to use all the nozzles in one inkjet head 24 for printing. In this case, the number of nozzles required for printing in one inkjet head 24 is n=200.

[0067] 6, the areas Pw in which two adjacent inkjet heads 24 eject ink onto the moving printing surface overlap each other. For example, the printing area Pw1 of inkjet head 24b overlaps with half of the printing area Pw2 of inkjet head 24c. However, this is not limiting, and the printing area Pw1 of inkjet head 24b may overlap with more than half of the printing area Pw2 of inkjet head 24c.

[0068] Next, in this embodiment, a case where a display panel 2c having a third definition Pd is printed using the line head unit 20 will be described with reference to Figures 7 and 8. The third definition Pd is 222 ppi.

[0069] When the resolution Pd is 222 ppi, equation (5) gives Pp = 114.414414 μm. To set Hp = Pp, equation (2) sets θ = 42.50665 deg. Furthermore, when the second angle Φ = 0 deg, equation (4) gives Pw = 45765.76577 μm, so Pw / Mp = 1.9819812. Furthermore, since Mp / Hp = 201.8181, Mp is not an integer multiple of Hp. Therefore, when the second angle Φ = 0 deg, equation (3) is not satisfied.

[0070] Here, the second angle Φ is adjusted to make Mp an integer multiple of Hp. Below, a case where MpΦ is 201 times Hp, that is, n=201, in equation (3) will be described. n=201 is chosen because it is the closest integer to and smaller than Mp / Hp (=201.8181) when the second angle Φ=0 deg.

[0071] When n=201, MpΦ=201×Hp=22997.29 μm from equation (3). Here, Mp=23090.9 μm, and therefore, from equation (1), the second angle Φ=5.160897 deg.

[0072] The amount of misalignment Δp in the Y direction between the nozzles of inkjet head 24a and the nozzles of inkjet head 24b shown in FIG. 7 when the second angle Φ=0 and when the second angle Φ=5.160897 deg is expressed as follows:

[0073] Δp=(201.8181−201)×Hp=93.60242μm

[0074] Using these, the inkjet head θ rotation mechanism 29 is controlled to position the inkjet head 24 so that θ = 42.50665 deg. The line head unit Φ rotation mechanism 22 is also controlled to position the line head unit 20 so that Φ = 5.1608970 deg (FIG. 8). These settings allow the Y-direction pitch of all nozzles arranged on the line head unit 20 to be adjusted to Hp (= 114.4144 μm). Therefore, Pp = 114.414414 μm, and the resolution Pd is 222 ppi. In this case, n = 201, so 201 nozzles are used for printing in one inkjet head 24.

[0075] 8, the Y-direction distance (Hp) between the multiple nozzles formed in one inkjet head 24 is adjusted by setting the first angle θ in accordance with the resolution Pd of the display panel 2. Furthermore, the widthwise (Y-direction) spacing of the multiple inkjet heads 24 is adjusted by setting the second angle Φ in accordance with the resolution Pd of the display panel 2. In this way, the Y-direction pitch of all the nozzles arranged in the line head unit 20 can be adjusted to match the resolution Pd of the display panel 2.

[0076] So far, we have explained how to adjust the nozzle pitch when the resolution Pd is 440 ppi, 220 ppi, and 222 ppi. Here, the calculation results for the second angle Φ and the number of nozzles used for printing (hereinafter referred to as the number of nozzles used) for the low-resolution side (220 to 230 ppi) and high-resolution side (430 to 440 ppi) resolution Pd are shown in Figures 17A, 17B, 18A, and 18B.

[0077] FIG. 17A is a graph (low definition side) showing the relationship between the resolution Pd of the display panel 2 and the second angle Φ of the line head unit 20. FIG. 17B is a graph (low definition side) showing the relationship between the resolution Pd of the display panel 2 and the number of nozzles in use of the inkjet head 24. FIG. 18A is a graph (high definition side) showing the relationship between the resolution Pd of the display panel 2 and the second angle Φ of the line head unit 20. FIG. 18B is a graph (high definition side) showing the relationship between the resolution Pd of the display panel 2 and the number of nozzles in use of the inkjet head 24.

[0078] In Figures 17A and 17B, when the resolution Pd = 220 ppi (second resolution Pd), as described above, the second angle Φ of the line head unit 20 is 0 deg (Figure 17A), and the number of nozzles used is 200 (Figure 17B).

[0079] As the resolution Pd gradually increases from 220 ppi, the second angle Φ gradually increases while the number of active nozzles remains at 200. The resolution Pd when the number of active nozzles is 200 and the second angle Φ is around 6 degrees is approximately the same as the resolution Pd when the number of active nozzles is 201 and the second angle Φ is 0. In this way, as the resolution Pd increases, the number of active nozzles increases and the second angle Φ repeatedly increases and decreases.

[0080] 17A and 17B for the low-resolution side, as the resolution Pd increases, the number of nozzles in use increases and the second angle Φ repeatedly increases and decreases. On the high-resolution side, for example, the resolution Pd when the number of nozzles in use is 391 and the second angle Φ is around 4 degrees is approximately the same as the resolution Pd when the number of nozzles in use is 392 and the second angle Φ is 0. As described above, when the resolution Pd is in the range of 220 ppi to 440 ppi, it is sufficient to set the second angle Φ in the range of 0 to 6 degrees.

[0081] 17A and 18A, the resolution Pd at which the second angle Φ=0 exists approximately every 1 ppi. That is, the resolution Pd at which the line head unit 20 does not need to rotate can be printed approximately every 1 ppi.

[0082] In this embodiment, the maximum resolution Pd that can be applied in one scan is designed to be 440 ppi as shown in Figure 5, but if it is acceptable to apply it in multiple print scans, it can be used for panels with even higher resolution.

[0083] Furthermore, on the low-resolution side, while Figure 6 shows an example in which the resolution Pd is 220 ppi, it is also possible to achieve 220 ppi by setting the resolution Pd as shown in Figure 5 to 440 ppi and using every other nozzle in the Y direction. In this case, increasing the first angle θ and further adjusting the second angle Φ makes it possible to achieve resolutions down to 110 ppi. Furthermore, in this case, increasing the pitch of the nozzles used makes it possible to further reduce the resolution Pd. In this way, by designing the printer to support resolutions from 440 ppi down to half that, 220 ppi, when all nozzles are used, it is possible to achieve any resolution Pd below 440 ppi.

[0084] As shown in Fig. 15A, the inkjet head 24 used in this example has row B positioned parallel to row A at a distance of 8.0433 mm. Row B is shifted from row A by 84.66667 µm in the direction along row A. Fig. 15B is a plan view illustrating the minimum shift amount ΔY in the Y direction between the nozzles arranged in row A and the nozzles arranged in row B when the inkjet head 24 is tilted by the first angle θ.

[0085] 17C and 18C show the results of calculating the deviation ΔY at low resolution (220-230 ppi) and high resolution (430-440 ppi). In Figures 17C and 18C, at resolution Pd where the deviation ΔY = 0, as indicated by point 71, the nozzles in row A and the nozzles in row B are adjacent to each other in the printing direction (X direction).

[0086] In this way, when the inkjet head 24 is provided with multiple rows and a resolution Pd is selected that makes the deviation ΔY 0, it is possible to prevent all nozzles in one row from being used for printing. This makes it possible to deal with the problem of ink not being ejected from the nozzles in the other rows, which leads to an increase in the operating rate of the inkjet printing device 1.

[0087] (2) Next, the alignment method for the display panel 2 will be explained with reference to FIG.

[0088] The display panel 2 is adsorbed onto the substrate adsorption table 11 and arranged parallel to the XY plane. Next, an alignment camera (not shown) detects the positions of alignment marks and pixels (not shown) within the display panel 2. Furthermore, a Yα drive mechanism (not shown) below the substrate adsorption table 11 is operated to rotate the substrate adsorption table 11 so that the pixel arrangement is parallel to the printing direction (X direction).

[0089] Furthermore, the relative positions of the nozzles and substrate 3 in the X and Y directions are measured and adjusted using an alignment camera. At this time, a test substrate (not shown) is printed using the line head unit 20, the first angle θ and second angle Φ of which have been adjusted in advance. The positional relationship between the nozzles and the alignment camera is calibrated by measuring the pixels printed on the test substrate with the alignment camera. The calibrated alignment camera is used to adjust the misalignment between the pixels of the display panel 2 and the nozzle positions. In this case, the misalignment in the Y direction is adjusted using the Yα drive mechanism. Furthermore, the misalignment in the X direction is adjusted using the X-axis slider 9. As described above, test printing is performed using one combination of the first angle θ and the second angle Φ, and the pixels are measured with the alignment camera to confirm the positional relationship between the alignment camera and the nozzles.

[0090] The first angle θ and second angle Φ, which are set based on the target resolution Pd, are then input to the inkjet ejection control unit, which calculates the ejection timing of each nozzle based on the input first angle θ and second angle Φ so that ejection is synchronized with the pixel position in the X direction of the display panel.

[0091] (3) Finally, the actual printing operation will be explained using FIG. The inkjet printing device 1 shown in Fig. 2 is arranged with one line head unit 20. The above-mentioned one line head unit 20 is configured to eject ink of one color. Therefore, when printing with three colors is required, such as the display panel 2 shown in Fig. 1, the inkjet printing device 1 has three line head units 20 that eject ink of different color tones arranged in a row along the printing direction (X direction).

[0092] For each of the three line head units 20, the nozzle pitch in the Y direction is adjusted in (1) above, and the relative position between the display panel 2 to be printed and the nozzles is adjusted in (2) above according to the color tone. Next, the X-axis slider 9 is scanned from the position shown by the solid line in Figure 2 to the position shown by the dashed line in Figure 2. At this time, the display panel 2 on the substrate suction table 11 passes below the inkjet heads 24 of the three line head units 20 at a constant speed.

[0093] When the display panel 2 passes under the inkjet heads 24 of the three line head units 20, the nozzles of the three line head units 20 eject droplets in response to ejection commands sent from the inkjet ejection control unit, thereby printing a display panel having the target definition Pd.

[0094] (Embodiment 2) Next, a second embodiment will be described with reference to Figures 9 to 13. The difference between the first embodiment and the second embodiment is that the inkjet printing apparatus 1 includes a plurality of line head units 20.

[0095] In the line head unit 20 of the second embodiment shown in Fig. 9, the distance Mp between the link rotation shaft members 23c is set to Mp = 46181.82 µm (= 46.18182 mm), which is twice as long as that of the first embodiment. If the inkjet head 24 used is wide or if the link rotation shaft members 23c are large in order to make them more precise, it is conceivable to set Mp to a larger value. Other matters not described are the same as those in the first embodiment.

[0096] When Mp is set in this way, in order to correspond to the resolution Pd=220 ppi (that is, Pp=Hp=115.4545 μm), the first angle θ is set to 42.98588 degrees according to equation (2).

[0097] Furthermore, Pw is calculated as Pw=46181.82 μm (=46.18182 mm) from equation (4). In this case, Pw=Mp, so all of the nozzles of the inkjet head 24 are used for printing.

[0098] In this embodiment, if the resolution Pd is to be higher than 220 ppi, the first angle θ is further reduced. In this case, there will be a location between adjacent inkjet heads 24 where the nozzle pitch in the Y direction is wider than Hp.

[0099] FIG. 10 illustrates the case where the inkjet head 24 is rotated to correspond to a resolution of Pd=440 ppi (i.e., Pp=Hp=57.72727 μm). In this case, the first angle θ is set to θ=19.93227 degrees using equation (2). Furthermore, the printing width Pw is Pw=23090.90 μm (=23.09090 mm). In this case, Pw=(½)×Mp, and a non-printed area of ​​the same width as Pw (an area where the nozzle pitch in the Y direction is wider than Hp) appears between adjacent inkjet heads 24. Areas 30a, 30c, 30e, 30g, and 30i shown in FIG. 10 are printed areas. Areas 30b, 30d, 30f, and 30h are non-printed areas.

[0100] In this case, as shown in Figure 11, a sub-line head unit 20B is arranged to complement the areas not printed by the main line head unit 20A. This makes it possible to prevent unprinted areas from appearing. The main line head unit 20A is an example of a "first line head unit." The sub-line head unit 20B is an example of a "second line head unit."

[0101] The main line head unit 20A and the sub-line head unit 20B form a dual line head unit 43. The dual line head unit 43 will be described with reference to Fig. 11. An inkjet printing device 1 equipped with the dual line head unit 43 is shown in Fig. 13.

[0102] <Configuration> In this embodiment, a line head unit gantry 40 is provided. The line head unit gantry 40 rotates the two line head units 20A and 20B simultaneously. This embodiment also includes a gantry Φ rotation mechanism 42 and a line head unit transfer mechanism 50 that moves the sub-line head unit 20B laterally along the line head unit gantry 40. The line head unit transfer mechanism 50 is an example of a "moving mechanism section."

[0103] First, we will explain the configuration of the gantry Φ rotation mechanism 42. The gantry Φ rotation mechanism 42 includes a gantry Φ rotation shaft member 42c, a Φ axis guide 42g2, a Φ axis table 42t, a rotary slide mechanism 42r, and a Φ axis horizontal slide guide 42g1.

[0104] The gantry Φ rotating shaft member 42c is disposed on the upper surface of one side of the head unit support portion 16, which is installed on both sides of the surface plate 17. The gantry Φ rotating shaft member 42c connects the head unit support portion 16 to a first end of the line head unit gantry 40. The gantry Φ rotating shaft member 42c allows the line head unit gantry 40 to rotate relative to the head unit support portion 16 around the central axis of the gantry Φ rotating shaft member 42c, which is perpendicular to the XY plane.

[0105] The Φ-axis guide 42g2 is disposed on the upper surface of the other side of the head unit support part 16 and moves the Φ-axis table 42t relative to the head unit support part 16 in the X direction. The rotary sliding mechanism 42r is disposed on the upper surface of the Φ-axis table 42t and connects the Φ-axis table 42t and the Φ-axis lateral sliding guide 42g1. The rotary sliding mechanism 42r causes the Φ-axis lateral sliding guide 42g1 to rotate relative to the Φ-axis table 42t around an axis that is perpendicular to the XY plane and passes through the rotary sliding mechanism 42r. A second end of the line head unit gantry 40 is connected to the Φ-axis lateral sliding guide 42g1. The Φ-axis lateral sliding guide 42g1 causes the line head unit gantry 40 to move relative to the rotary sliding mechanism 42r in the direction in which the Φ-axis lateral sliding guide 42g1 extends.

[0106] A φ-axis motor 42m is attached to the upper surface of the other side of the head unit support part 16 via a φ-axis motor bracket 42b. The φ-axis motor 42m is connected to a φ-axis ball screw 42s, and a nut portion (not shown) that engages with the φ-axis ball screw 42s is connected to the φ-axis table 42t. With this configuration, the φ-axis table 42t moves in the X direction when the φ-axis motor 42m rotates. Meanwhile, the line head unit gantry 40 rotates relatively around the axis of a gantry φ rotation shaft member 42c disposed on one side of the head unit support part 16. That is, the line head unit gantry 40 is tilted with respect to the head unit support part 16 by the gantry φ rotation mechanism 42.

[0107] The sub line head unit 20B is disposed on one side of the line head unit gantry 40. The main line head unit 20A is disposed on the other side of the line head unit gantry 40. As a result, when the line head unit gantry 40 rotates, the two line head units 20A and 20B rotate.

[0108] Next, a description will be given of the configuration of the line head unit transfer mechanism 50. The line head unit transfer mechanism 50 moves the sub line head unit 20B along one side surface of the line head unit gantry 40.

[0109] A line head unit transfer axis table 50t is disposed on one side surface of the line head unit gantry 40 via a line head unit transfer axis guide 50g that extends along one side surface of the line head unit gantry 40. A line head unit transfer axis motor 50m is disposed on the line head unit gantry 40 via a line head unit transfer axis motor bracket 50b. A line head unit transfer axis ball screw 50s is connected to the line head unit transfer axis motor 50m. A nut portion (not shown) that moves along the line head unit transfer axis ball screw 50s is connected to the line head unit transfer axis table 50t.

[0110] The position of the line head unit transfer axis table 50t is controlled by a line head unit transfer axis control means (not shown). Specifically, the line head unit transfer axis control means feedback controls the drive amount of the line head unit transfer axis motor 50m for the line head unit transfer axis table 50t so that the detection result of a line head unit transfer axis table position detection means (not shown) that detects the position of the line head unit transfer axis table 50t coincides with the target position of the line head unit transfer axis table 50t.

[0111] Furthermore, the sub line head unit 20B is fixed to the line head unit transfer axis table 50t. Meanwhile, the main line head unit 20A is fixed to the other side surface of the line head unit gantry 40 via a line head unit mounting plate 41. That is, the line head unit transfer mechanism 50 moves the sub line head unit 20B relative to the line head unit gantry 40 along the line head unit transfer axis guide 50g.

[0112] <Operation> Next, a description will be given of the printing operation of the inkjet printing apparatus 1 of this embodiment. The operation of the gantry Φ rotation mechanism 42 that adjusts the nozzle position of the main line head unit 20A is the same as the operation of the line head unit Φ rotation mechanism 22 of the first embodiment described above. Therefore, the adjustment of the nozzle position of the main line head unit 20A will be omitted, and only the adjustment of the nozzle position of the sub-line head unit 20B will be described.

[0113] As mentioned above, in this embodiment, when supporting a resolution Pd of 220 ppi or more, the areas 30b, 30d, 30f, 30h, and 30j that are not printed by the main line head unit 20A must be complemented by the sub-line head unit 20B, as shown in Figure 11.

[0114] FIG. 11 shows the case where a display panel 2 having the same resolution Pd as FIG. 10, 440 ppi (Pp = Hp = 57.72727 μm), is coated. In this case, the first angle θ of the inkjet head 24 is set to θ = 19.93227 deg. Therefore, the printing width Pw = 23090.90 μm (= 23.09090 mm). In this embodiment, Mp is set to 46181.82 μm (= 46.18182 mm), so the printing width Pw = (1 / 2) × Mp. Therefore, as described above, unprinted areas appear between adjacent inkjet heads 24.

[0115] Furthermore, since Mp = 800 × Hp, Mp is an integer multiple of Hp. Therefore, the second angle Φ is set to 0. Specifically, the gantry Φ rotation mechanism 42 is adjusted so that the second angle Φ = 0. Furthermore, the inkjet head θ rotation mechanism 29 of each line head unit 20A, 20B is adjusted so that the first angle θ = 19.93227 deg.

[0116] Furthermore, the position of the sub line head unit 20B is adjusted by the line head unit transfer mechanism 50. Specifically, the position of the sub line head unit 20B is adjusted so that the areas 30b, 30d, 30f, 30h, and 30j that can be printed by the sub line head unit 20B correspond to the areas 30b, 30d, 30f, 30h, and 30j that cannot be printed by the main line head unit 20A, and so that the nozzle pitch in the Y direction is the same. This adjustment of the nozzle positions of the sub line head unit 20B is performed by measuring pixels printed on a test substrate with an alignment camera, as was done in the first embodiment.

[0117] Next, the case where the resolution Pd=439.95 ppi will be described using Figure 12. Figure 12 shows a state in which the number of nozzles used for printing in the inkjet head 24 of the sub-line head unit 20B is reduced by one. Since the number of nozzles of the inkjet head 24 actually used for printing is 400, 399 nozzles are used for printing.

[0118] When the resolution Pd=439.95 ppi, equation (5) gives Pp=Hp=57.733833 μm. In this case, equation (4) gives the printing width Pw of the main line head unit 20A as Pw=23093.533 μm. Meanwhile, since 399 nozzles are used for printing in the sub line head unit 20B, the printing width Pw of the sub line head unit 20B is Pw=23035.799 μm. Therefore, the printing width Pw obtained by adding up the printing widths Pw of the line head units 20A and 20B is Pw=46129.332 μm. The second angle Φ is set so that this total printing width Pw matches MpΦ.

[0119] In this case, the second angle Φ is calculated as Φ = 2.731930 deg from equation (1). Meanwhile, the first angle θ is calculated as θ = 19.934632 deg from equation (2). The gantry Φ rotation mechanism 42 and inkjet head θ rotation mechanism 29 are controlled so that the first angle θ and second angle Φ are calculated as above.

[0120] Furthermore, as described above, the position of the sub-line head unit 20B is adjusted by the line head unit transfer mechanism 50. That is, the positions are adjusted so that the areas 30b, 30d, 30f, 30h, and 30j that can be printed by the sub-line head unit 20B correspond to the areas 30b, 30d, 30f, 30h, and 30j that cannot be printed by the main line head unit 20A, and so that the nozzle pitch in the Y direction is the same. This results in a resolution Pd of 439.95 ppi.

[0121] So far, we have explained how to adjust the nozzle pitch when the resolution Pd is 440 ppi and 439.95 ppi. Here, the calculation results for the second angle Φ and the number of nozzles in use of the inkjet head 24 of the sub-line head unit 20B for the resolution Pd on the low resolution side (220 to 230 ppi) and high resolution side (430 to 440 ppi) are shown in Figures 19A, 19B, 20A, and 20B.

[0122] Fig. 19A is a graph (low definition side) showing the relationship between the resolution Pd of the display panel 2 and the second angle Φ of the line head unit 20. Fig. 19B is a graph (low definition side) showing the relationship between the resolution Pd of the display panel 2 and the number of nozzles used in the sub line head unit 20B. Fig. 20A is a graph (high definition side) showing the relationship between the resolution Pd of the display panel 2 and the second angle Φ of the line head unit 20. Fig. 20B is a graph (high definition side) showing the relationship between the resolution Pd of the display panel 2 and the number of nozzles used in the sub line head unit 20B.

[0123] In Fig. 19A, when the resolution Pd = 220 ppi, the second angle Φ = 0. Also, in Fig. 19B, the number of nozzles in use is 0. In this case, this indicates that printing by the sub-line head unit 20B is not necessary.

[0124] As the resolution Pd gradually increases from 220 ppi, the second angle Φ gradually increases while the number of active nozzles remains at 200. The resolution Pd when the number of active nozzles is 0 and the second angle Φ is around 4 degrees is approximately the same as the resolution Pd when the number of active nozzles is 1 and the second angle Φ is 0. In this way, as the resolution Pd increases, the number of active nozzles increases and the second angle Φ repeatedly increases and decreases.

[0125] 20A and 20B, as with the low-resolution side shown in FIGS. 19A and 19B, as the resolution Pd increases, the number of nozzles in use increases and the second angle Φ repeatedly fluctuates. On the high-resolution side, for example, the resolution Pd when the number of nozzles in use is 382 and the second angle Φ is around 3 degrees is approximately the same as the resolution Pd when the number of nozzles in use is 383 and the second angle Φ is 0. As described above, when the resolution Pd is in the range of 220 ppi to 440 ppi, it is sufficient to set the second angle Φ in the range of 0 to 4 degrees.

[0126] As shown in FIGS. 19A and 20A, the resolution Pd at which the second angle Φ=0, i.e., the line head unit 20 no longer needs to rotate, occurs approximately every 0.5 ppi. Comparing FIG. 17A and FIG. 19A for the first embodiment, the cycle at which the second angle Φ=0 in FIG. 19A is approximately half the cycle at which the second angle Φ=0 in FIG. 17A. This is because, in the first embodiment, the section covered by 400 nozzles is adjusted in units of one nozzle, whereas in the second embodiment, the section covered by 800 nozzles is adjusted in units of one nozzle. Furthermore, in the second embodiment, the maximum value of the second angle Φ can be made smaller than in the first embodiment. The results of calculating the deviation amount ΔY on the low resolution side (220 to 230 ppi) and the high resolution side (430 to 440 ppi) are shown in FIGS. 19C and 20C.

[0127] (Embodiment 3) Next, a third embodiment will be described with reference to Fig. 14. In the first embodiment, the θ-axis drive unit 26 is used to adjust the first angle θ, whereas in the third embodiment, both ends of the movable link 23b are driven by separate drive shafts. Items that will not be described are the same as those in the first and second embodiments.

[0128] In this embodiment, a movable link R drive motor 27m is attached to one side of the θ-axis table 25a via a movable link R drive motor bracket 27b. A movable link R drive ball screw 27s is connected to the movable link R drive motor 27m. A nut portion of the movable link R drive ball screw 27s is connected to one end of the movable link 23b. The movable link R drive motor 27m is controlled by movable link R drive shaft control means (not shown). The movable link R drive shaft control means feedback-controls the drive amount of the movable link R drive motor 27m so that the detection result from movable link R drive shaft position detection means (not shown), which detects the position of one end of the movable link 23b, becomes a target position for one end of the movable link 23b.

[0129] Meanwhile, a movable link L drive motor 28m is attached to the other side of the θ-axis table 25a via a movable link L drive motor bracket 28b. A movable link L drive ball screw 28s is connected to the movable link L drive motor 28m. A nut portion of the movable link L drive ball screw 28s is connected to the other end of the movable link 23b. The movable link L drive motor 28m is controlled by a movable link L drive shaft control means (not shown). The movable link L drive shaft control means feedback-controls the drive amount of the movable link L drive motor 28m so that the detection result of a movable link L drive shaft position detection means (not shown), which detects the position of the other end of the movable link 23b, matches the target position of the other end of the movable link 23b. Furthermore, the movable link R drive shaft control means and the movable link L drive shaft control means can make the movement amounts of one end and the other end of the movable link 23b the same.

[0130] When a drive shaft is provided at each end of movable link 23b as described above, movable link 23b can be driven with higher precision than when one drive shaft is provided as in embodiment 1. Therefore, inkjet head 24 can be rotated with higher precision.

[0131] In this embodiment, the inkjet head 24 shown in FIG. 15A is used, in which 400 nozzles are formed in a row. However, instead of this, the inkjet head 24 shown in FIGS. 16A and 16B may be used, in which 800 nozzles are formed in a row. When the first angle θ is set to correspond to the resolution Pd=440 ppi, the number of nozzles used is 400. Therefore, in an inkjet head 24 in which 800 nozzles are formed in a row, some nozzles are not used for printing. Furthermore, in this case, adjacent inkjet heads 24 have nozzles that are adjacent to each other along the printing direction (X direction). This makes it possible to address the problem of ink not being ejected from one of adjacent nozzles.

[0132] The condition that can address this problem is shown by equation (6). When the resolution Pd=440 ppi, equation (5) gives Pp=Hp=57.72727 μm. When 800 nozzles are formed on one inkjet head 24, equation (4) gives Pw=4681.818 μm. Also, Mp=23090.909 μm is set. In this case, equation (6) is satisfied, so there is a nozzle that can address the problem of ink not being ejected.

[0133] Pw≧2×Mp...Equation (6)

[0134] In this embodiment, a link rotation shaft member 23c is disposed on each end of the inkjet head 24. However, the inkjet head 24 may need to be replaced due to clogged nozzles or other reasons. For this reason, the line head unit 20 may further include a mounting plate (not shown) to which the inkjet head 24 can be detached. In this case, the link rotation shaft members 23c are disposed on both ends of the mounting plate. The inkjet head 24 is attached to this mounting plate in a detachable and replaceable manner. Furthermore, the inkjet head 24 needs to be positioned with high precision relative to the link rotation shaft members 23c. For this purpose, the inkjet head 24 is attached to the mounting plate using an expansion pin or the like.

[0135] Although the line head unit 20 in this embodiment has ten inkjet heads 24, according to the method of the present invention, even if the number of inkjet heads 24 is further increased, the number of line head unit Φ rotation mechanisms 22 and inkjet head θ rotation mechanisms 29 that adjust the rotation of the inkjet heads 24 does not increase.

[0136] As described above, according to the inkjet printing devices of the first to third embodiments, even if the number of inkjet heads 24 used is increased to widen the width of the printing object, the pitch of the nozzles in the direction perpendicular to the printing direction can be adjusted arbitrarily without increasing the number of mechanisms for driving the inkjet heads 24. [Industrial Applicability]

[0137] The inkjet printing apparatus according to the above aspect of the present invention is effective for applying ink or the like to a printing object with high resolution and a constant pitch, and can be applied to inkjet printing apparatuses for printing organic EL light-emitting bodies, hole transport layers, or electron transport layers, or for printing color filters, etc. [Explanation of symbols]

[0138] 1. Inkjet printing device 2 Display Panel 3. Circuit Board 20 line head unit 20A Main Line Head Unit 20B Sub-line head unit 21 line head base (first base member, second base member) 22 Line head unit Φ rotation mechanism (line head unit rotation mechanism part) 23 Parallel link mechanism 23a permalink 23b Movable link (connecting member) 24 inkjet heads (first inkjet head, second inkjet head) 24a1 nozzle 24a2 nozzle 24a3 nozzle 24a4 nozzle 25 θ-axis sliding mechanism 29 Inkjet head θ rotation mechanism (inkjet head rotation mechanism) 40 Line head unit gantry 43 Dual Line Head Unit 50 Line head unit transfer mechanism (moving mechanism part) Pd definition θ 1st angle Φ 2nd angle

Claims

1. a first base member; and a first line head unit attached to the first base member so as to be integrally rotatable relative to the first base member about an axis perpendicular to a printing surface, the first line head unit including a plurality of first inkjet heads each having a plurality of nozzles arranged in a straight line and each applying the same type of ink; an inkjet printing device including: a line head unit rotation mechanism that rotates the first line head unit relatively to the printing surface about an axis perpendicular to the printing surface.

2. A first line head unit comprising: a first base member; a first line head unit attached to the first base member so as to be rotatable relative to the first base member about an axis perpendicular to a printing surface; and a plurality of first inkjet heads each having a plurality of nozzles arranged in a straight line for applying the same type of ink; a line head unit rotating mechanism that rotates the first line head unit relative to the printing surface about an axis perpendicular to the printing surface; a second base member; and a second line head unit attached to the second base member so as to be rotatable relative to the second base member about an axis perpendicular to the printing surface, the second line head unit including a plurality of second inkjet heads each having a plurality of nozzles linearly arranged to apply the same type of ink; a movement mechanism that moves the first line head unit relative to the second line head unit in a direction intersecting a direction in which the printing surface moves.

3. A first line head unit comprising: a first base member; a first line head unit attached to the first base member so as to be rotatable relative to the first base member about an axis perpendicular to a printing surface; and a plurality of first inkjet heads each having a plurality of nozzles arranged in a straight line for applying the same type of ink; a line head unit rotating mechanism that rotates the first line head unit relative to the printing surface about an axis perpendicular to the printing surface; the first line head unit includes a connecting member that connects one ends of the first inkjet heads to each other, The first base member, the first inkjet heads, and the connecting member form a parallel link mechanism.

4. the first line head unit further includes an inkjet head rotating mechanism that rotates the first inkjet heads relative to the first base member by moving the connecting member relative to the first base member; The inkjet printing apparatus of claim 3.

5. A first line head unit comprising: a first base member; a first line head unit attached to the first base member so as to be rotatable relative to the first base member about an axis perpendicular to a printing surface; and a plurality of first inkjet heads each having a plurality of nozzles arranged in a straight line for applying the same type of ink; a line head unit rotation mechanism that rotates the first line head unit relative to the printing surface about an axis perpendicular to the printing surface, an inkjet printing device, wherein areas in which two adjacent first inkjet heads among the plurality of first inkjet heads eject ink onto the moving printing surface overlap each other.

6. The inkjet printing apparatus according to claim 5 , wherein the areas in which the two first inkjet heads that apply the same type of ink eject ink onto the moving printing surface overlap each other by half or more.

7. 7. The inkjet printing device according to claim 5, wherein nozzles arranged in one of the two first inkjet heads that apply the same type of ink and nozzles arranged in the other of the two first inkjet heads are configured to be capable of being positioned along a direction in which the printing surface moves.

8. A first line head unit comprising: a first base member; a first line head unit attached to the first base member so as to be rotatable relative to the first base member about an axis perpendicular to a printing surface; and a plurality of first inkjet heads each having a plurality of nozzles arranged in a straight line for applying the same type of ink; a line head unit rotation mechanism that rotates the first line head unit relative to the printing surface about an axis perpendicular to the printing surface, an inkjet printing device configured such that a distance between two adjacent nozzles arranged on one of the plurality of first inkjet heads along a direction in which the plurality of first inkjet heads are arranged can change by a factor of two or more before and after relative rotation of the plurality of first inkjet heads with respect to the first base member.

9. A first line head unit comprising: a first base member; a first line head unit attached to the first base member so as to be rotatable relative to the first base member about an axis perpendicular to a printing surface; and a plurality of first inkjet heads each having a plurality of nozzles arranged in a straight line for applying the same type of ink; a line head unit rotation mechanism that rotates the first line head unit relative to the printing surface about an axis perpendicular to the printing surface, a plurality of nozzle rows each including a plurality of nozzles are arranged in each of the first inkjet heads; A nozzle arranged in one of the plurality of nozzle rows and a nozzle arranged in the other of the plurality of nozzle rows a nozzle disposed on said inkjet printing apparatus, said nozzles being configured to be positionable along a direction of movement of said printing surface.

10. A first line head unit comprising: a first base member; a first line head unit attached to the first base member so as to be rotatable relative to the first base member about an axis perpendicular to a printing surface; and a plurality of first inkjet heads each having a plurality of nozzles arranged in a straight line for applying the same type of ink; a line head unit rotating mechanism that rotates the first line head unit relative to the printing surface about an axis perpendicular to the printing surface; the first line head unit includes a mounting plate to which the first inkjet heads are detachably attached; The plurality of first inkjet heads are attached to the first line head unit via the mounting plate.

11. a first base member; and a first line head unit attached to the first base member so as to be integrally rotatable relative to the first base member about an axis perpendicular to a printing surface, the first line head unit including a plurality of first inkjet heads each having a plurality of nozzles arranged in a straight line and each applying the same type of ink; a line head unit rotation mechanism that rotates the first line head unit relative to the printing surface about an axis perpendicular to the printing surface, rotating the first inkjet heads in unison so that a distance between the nozzles in a direction perpendicular to a direction in which the printing surface moves corresponds to a predetermined resolution; rotating the first line head unit by the line head unit rotation mechanism so that a distance between two adjacent first inkjet heads among the plurality of first inkjet heads in a direction perpendicular to a direction in which the printing surface moves corresponds to the predetermined resolution; a step of moving the printing surface relative to the first line head unit and ejecting ink from the multiple nozzles toward the printing surface to perform printing.

12. A first line head unit comprising: a first base member; a first line head unit attached to the first base member so as to be rotatable relative to the first base member about an axis perpendicular to a printing surface, the first line head unit comprising a plurality of first inkjet heads each having a plurality of nozzles arranged in a straight line for applying the same type of ink; a line head unit rotation mechanism that rotates the first line head unit relative to the printing surface about an axis perpendicular to the printing surface, rotating the first inkjet heads so that a distance between the nozzles in a direction perpendicular to a direction in which the printing surface moves corresponds to a predetermined resolution; rotating the first line head unit by the line head unit rotation mechanism so that a distance between two adjacent first inkjet heads among the plurality of first inkjet heads in a direction perpendicular to a direction in which the printing surface moves corresponds to the predetermined resolution; a step of moving the printing surface relative to the first line head unit and discharging ink from the multiple nozzles toward the printing surface to perform printing; and rotating the first line head unit by the line head unit rotation mechanism so that nozzles arranged in one first inkjet head and nozzles arranged in the other first inkjet head of two adjacent first inkjet heads among the plurality of first inkjet heads are positioned along a direction in which the printing surface moves.

13. A first line head unit comprising: a first base member; a first line head unit attached to the first base member so as to be rotatable relative to the first base member about an axis perpendicular to a printing surface; and a plurality of first inkjet heads each having a plurality of nozzles arranged in a straight line for applying the same type of ink; a line head unit rotation mechanism that rotates the first line head unit relative to the printing surface about an axis perpendicular to the printing surface, rotating the first inkjet heads so that a distance between the nozzles in a direction perpendicular to a direction in which the printing surface moves corresponds to a predetermined resolution; rotating the first line head unit by the line head unit rotation mechanism so that a distance between two adjacent first inkjet heads among the plurality of first inkjet heads in a direction perpendicular to a direction in which the printing surface moves corresponds to the predetermined resolution; a step of moving the printing surface relative to the first line head unit and discharging ink from the plurality of nozzles toward the printing surface to perform printing; a plurality of nozzle rows each including a plurality of nozzles are arranged in each of the first inkjet heads; The printing method further includes a step of rotating the first line head unit by the line head unit rotation mechanism so that nozzles arranged in one of the plurality of nozzle rows and nozzles arranged in the other of the plurality of nozzle rows are positioned along a direction in which the printing surface moves.

14. the inkjet head rotation mechanism includes a first motor that moves the connecting member relative to the first base member; 5. The inkjet printing apparatus of claim 4.

15. A first line head unit comprising: a first base member; a first line head unit attached to the first base member so as to be rotatable relative to the first base member about an axis perpendicular to a printing surface; and a plurality of first inkjet heads each having a plurality of nozzles arranged in a straight line for applying the same type of ink; a line head unit rotating mechanism that rotates the first line head unit relative to the printing surface about an axis perpendicular to the printing surface; A surface plate and a the first base member has a first end and a second end opposite to the first end with the first inkjet heads interposed therebetween; The first end is rotatably supported by the base, the line head unit rotation mechanism includes a second motor that rotates the first base member about the first end by moving the second end relative to the base plate; The inkjet printing apparatus of claim 1 .

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