Inkjet printing apparatus and printing method

Abstract

An object of the present invention is to suppress the number of components in an inkjet printing apparatus capable of arbitrarily adjusting the pitch between a plurality of nozzles. The inkjet printing apparatus includes: a first line head unit including a first base member and a plurality of first inkjet heads, the plurality of first inkjet heads being mounted on the first base member so as to be relatively rotatable about an axis orthogonal to the printing surface with respect to the first base member, and the plurality of first inkjet heads being linearly arranged with a plurality of nozzles; and a line head unit rotation mechanism unit that relatively rotates the first line head unit about an axis orthogonal to the printing surface with respect to the printing surface.

Description

Technical Field

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

[0002] In recent years, a method of manufacturing a device using an inkjet printing apparatus has attracted attention. The inkjet printing apparatus ejects droplets from a plurality of nozzles while controlling the positional relationship between the nozzles and the coating target portion of the printing object. As the printing object, a printing object in which the coating target portions of the printing object are arranged at a constant pitch, typified by a display device, is used.

[0003] In such a case, a method of coating is disclosed in which an inkjet head having a plurality of nozzles arranged at a constant pitch is rotated about an axis orthogonal to the surface of the printing object so that the pitch of the landed droplets coincides with the pitch of the coating target portions of the coating object (for example, Patent Document 1).

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent No. 4971560 Summary of the Invention

[0007] An inkjet printing apparatus according to an aspect of the present invention includes: a first line head unit including a first base member and a plurality of first inkjet heads, the plurality of first inkjet heads being mounted on the first base member so as to be relatively rotatable about an axis orthogonal to the printing surface with respect to the first base member, and the plurality of first inkjet heads having a plurality of nozzles arranged linearly and coating the same type of ink; and a line head unit rotation mechanism unit that relatively rotates the first line head unit about an axis orthogonal to the printing surface with respect to the printing surface.

[0008] In addition, a printing method according to an aspect of the present invention uses an inkjet printing apparatus including: a first line head unit having a first base member and a plurality of first inkjet heads, the plurality of first inkjet heads being mounted on the first base member so as to be relatively rotatable about an axis orthogonal to a printing surface with respect to the first base member, and the plurality of first inkjet heads being linearly arranged with a plurality of nozzles and coating the same type of ink; and a line head unit rotation mechanism unit that relatively rotates the first line head unit about an axis orthogonal to the printing surface with respect to the printing surface. The printing method includes the steps of: rotating the plurality of first inkjet heads so that a distance between the plurality of nozzles in a direction orthogonal to a moving direction of the printing surface becomes a distance corresponding to a specified definition; rotating the first line head unit by the line head unit rotation mechanism unit so that a distance between two adjacent first inkjet heads among the plurality of first inkjet heads in a direction orthogonal to the moving direction of the printing surface becomes a distance corresponding to the specified definition; 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 perform printing. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a top view of a display panel.

[0010] Figure 2 is a schematic top view of an inkjet printing apparatus according to Embodiment 1 of the present invention.

[0011] Figure 3 is a view showing Figure 2 a schematic top view of a line head unit and a line head unit Φ rotation mechanism mounted on the inkjet printing apparatus shown.

[0012] Figure 4 is a view showing Figure 2 a schematic top view of a state in which the line head unit is rotated in the inkjet printing apparatus shown.

[0013] Figure 5 is a view showing Figure 2 a top view of a relationship between nozzle positions and a printing object position in a case of printing a display panel with a first definition in the inkjet printing apparatus shown.

[0014] Figure 6 is a view showing Figure 2 a top view of a relationship between nozzle positions and a printing object position in a case of printing a display panel with a second definition in the inkjet printing apparatus shown.

[0015] Figure 7 is a view showing Figure 2 a top view of a case where nozzle positions and a printing object position do not match in a case of printing a display panel with a third definition in the inkjet printing apparatus shown.

[0016] Figure 8 It is a top view showing the relationship between the nozzle position and the printing object position when printing a display panel with the third definition in the inkjet printing apparatus of Embodiment 1 shown in Figure 2 the following figure.

[0017] Figure 9 It is a schematic top view of a line head unit mounted on the inkjet printing apparatus of Embodiment 2 of the present invention.

[0018] Figure 10 It is a view showing a state where tilt adjustment has been performed in one line head unit of the inkjet printing apparatus shown in Figure 9 the following figure to be consistent with the first definition.

[0019] Figure 11 It is a view showing a state where two line heads are combined in the inkjet printing apparatus shown in Figure 9 the following figure to enable printing with the first definition.

[0020] Figure 12 It is a view showing a state where position adjustment of a dual line head unit has been performed in the inkjet printing apparatus shown in Figure 9 the following figure to perform printing with the fourth definition.

[0021] Figure 13 It is a schematic top view of the inkjet printing apparatus of Embodiment 2.

[0022] Figure 14 It is a schematic top view of a line head mounted on the inkjet printing apparatus of Embodiment 3 of the present invention and a rotation mechanism for rotating the line head.

[0023] Figure 15A It is a top view showing the nozzle positions of the inkjet heads mounted on the line heads of Embodiments 1 to 3.

[0024] Figure 15B It is a top view showing the Y-direction position shift between the A-column nozzles and the B-column nozzles when the inkjet head mounted on the line head unit is tilted by an inclination angle θ.

[0025] Figure 16A It is a top view showing the nozzle positions of an inkjet head having 800 nozzles in one column mounted on the line head unit.

[0026] Figure 16B It is a top view showing the Y-direction position shift between the A-column nozzles and the B-column nozzles when the inkjet head having 800 nozzles formed in one column and mounted on the line head units of Embodiments 1 to 3 is tilted by an inclination angle θ.

[0027] Figure 17A It is a graph (low definition side) showing the relationship between the clarity of the display panel and the rotation angle of the line head unit in Embodiment 1 and Embodiment 3.

[0028] Figure 17B It is a graph (low definition side) showing the relationship between the clarity of the display panel and the number of nozzles used by the inkjet head in the line head unit in Embodiment 1 and Embodiment 3.

[0029] Figure 17C It is a graph (low definition side) showing the relationship between the clarity of the display panel and the offset amount of the nozzle position of the B column nozzles in Embodiment 1 and Embodiment 3.

[0030] Figure 18A It is a graph (high definition side) showing the relationship between the clarity of the display panel and the rotation angle of the line head unit in Embodiment 1 and Embodiment 3.

[0031] Figure 18B It is a graph (high definition side) showing the relationship between the clarity of the display panel and the number of nozzles used in Embodiment 1 and Embodiment 3.

[0032] Figure 18C It is a graph (high definition side) showing the relationship between the clarity of the display panel and the offset amount of the nozzle position of the B column nozzles in Embodiment 1 and Embodiment 3.

[0033] Figure 19A It is a graph (low definition side) showing the relationship between the clarity of the display panel and the rotation angle of the line head unit in Embodiment 2.

[0034] Figure 19B It is a graph (low definition side) showing the relationship between the clarity of the display panel and the number of nozzles used by the inkjet head in the sub-line head unit in Embodiment 2.

[0035] Figure 19C It is a graph (low definition side) showing the relationship between the clarity of the display panel and the offset amount of the nozzle position of the B column nozzles in Embodiment 2.

[0036] Figure 20A It is a graph (high definition side) showing the relationship between the clarity of the display panel and the rotation angle of the corresponding line head in Embodiment 2.

[0037] Figure 20B It is a graph (high definition side) showing the relationship between the clarity of the display panel and the number of nozzles used by the inkjet head in the sub-line head in Embodiment 2.

[0038] Figure 20CIt is a graph (high-definition side) showing the relationship between the clarity of the display panel and the offset of the nozzle position of the nozzle in column B in Embodiment 2.

[0039] Description of reference numerals:

[0040] 1 Inkjet printing device

[0041] 2 Display panel

[0042] 3 Substrate

[0043] 20 Line head unit

[0044] 20A Main line head unit

[0045] 20B Sub-line head unit

[0046] 21 Line head base (first base member, second base member)

[0047] 22 Line head unit Φ rotation mechanism (line head unit rotation mechanism section)

[0048] 23 Parallel link mechanism

[0049] 23a Fixed link

[0050] 23b Movable link (connecting member)

[0051] 24 Inkjet head (first inkjet head, second inkjet head)

[0052] 24a1 Nozzle

[0053] 24a2 Nozzle

[0054] 24a3 Nozzle

[0055] 24a4 Nozzle

[0056] 25 θ-axis sliding mechanism

[0057] 29 Inkjet head θ rotation mechanism (inkjet head rotation mechanism section)

[0058] 40 Stand for line head unit

[0059] 43 Dual line head unit

[0060] 50 Line head unit transfer mechanism (moving mechanism section)

[0061] Pd Clarity

[0062] θ First angle

[0063] Φ Second angle. Detailed implementation mode

[0064] Using Patent Document 1 Figure 7 and Figure 12 explain the conventional method. Patent Document 1 Figure 7 is a diagram showing the bottom surface of the inkjet head unit, and Patent Document 1 Figure 12 is a diagram showing the object to be printed.

[0065] As shown in Patent Document 1 Figure 7 the inkjet head unit includes a head mounting base 120, reference planes 120a, 120b, R inkjet heads 121a to 121h, G inkjet heads 122a to 122h, and B inkjet heads 123a to 123h.

[0066] In each of the R inkjet heads 121a to 121h, 200 nozzles are linearly formed at a constant pitch. For example, in the R inkjet head 121a, the nozzle 121a1 represents the first nozzle, and the nozzle 121a200 represents the 200th nozzle. The same applies to the G inkjet heads 122a to 122h and the B inkjet heads 123a to 123h. In addition, each inkjet head is provided with a rotational drive mechanism in the θ direction and a translational drive mechanism in the nozzle row direction.

[0067] As shown in Patent Document 1 Figure 12 in the object to be printed, red coloring pixels 100a, blue coloring pixels 100b, and green coloring pixels 100c are repeated in sequence along the X direction, and the pitch of the same coloring pixels is constantly arranged at 190.5 μm.

[0068] Next, explain the conventional method of ejecting droplets from the nozzles of the inkjet head onto the above object to be printed for coating.

[0069] Measure the X-direction pitch between the nozzles at both ends of each of the inkjet heads 121a to 121h, 122a to 122h, and 123a to 123h mounted on the inkjet head unit using a nozzle hole position measuring camera. For example, measure the pitch between the nozzle 121a1 and the nozzle 121a200 of the inkjet head 121a. Then, based on the measurement result of the nozzle hole position measuring camera, adjust the position of the rotational direction of the inkjet head 121a using the rotational drive mechanism so that the X-direction pitch between the nozzle 121a1 and the nozzle 121a200 is 190.5 μm. Perform the above operation on all the inkjet heads 121a to 121h, 122a to 122h, and 123a to 123h.

[0070] Moreover, the positions of the inkjet heads 121a to 121h are adjusted by a translation drive mechanism so that, among the R inkjet heads 121a to 121h adjacent to each other in the X direction, the distance in the X direction between the first nozzle, for example, nozzle 121a1 and nozzle 121b1 becomes 38.100 mm. The above operation is performed on all the inkjet heads 121a to 121h, 122a to 122h, and 123a to 123h.

[0071] Next, the positions of the inkjet heads 121a, 122a, and 123a are adjusted by a translation drive mechanism so that, among the inkjet heads 121a, 122a, and 123a adjacent to each other in the Y direction, the distances in the X direction between nozzle 121a1, nozzle 122a1, and nozzle 123a1 respectively become 1 / 3 of the pixel pitch, i.e., 63.5 μm. The above operation is performed on all the inkjet heads 121a to 121h, 122a to 122h, and 123a to 123h.

[0072] By adjusting the positions of all the inkjet heads 121a to 121h, 122a to 122h, and 123a to 123h in this way, the nozzle pitch in the X direction of all the inkjet heads 121a to 121h, 122a to 122h, and 123a to 123h is made to coincide with the pixel pitch in the X direction of the printing object.

[0073] Next, after aligning the printing object in the X, Y, and θ directions, the printing object is scanned below the inkjet head unit, so that the inkjet heads 121a to 121h, 122a to 122h, and 123a to 123h eject ink at a required timing. Thereby, the ink can be applied to the printing object with good accuracy.

[0074] However, in recent years, the size of display panels has been continuously increasing. In addition, in order to suppress uneven drying of the coating, the requirement for coating the entire width of the printing object substrate in one scan has been continuously increasing. In addition, the number of inkjet heads used has increased. In the conventional method in which two drive mechanisms are mounted on each inkjet head, the number of drive shafts has increased significantly, which has become a problem from the viewpoints of cost and equipment management.

[0075] The present invention has been completed in view of such problems, and an object thereof is to suppress the number of components in an inkjet printing apparatus capable of arbitrarily adjusting the pitch between a plurality of nozzles.

[0076] To achieve the above object, an inkjet printing apparatus according to an aspect of the present invention includes: a first line head unit including a first base member and a plurality of first inkjet heads, the plurality of first inkjet heads being mounted on the first base member so as to be relatively rotatable about an axis orthogonal to the printing surface with respect to the first base member, and the plurality of first inkjet heads being linearly arranged with a plurality of nozzles; and a line head unit rotation mechanism unit that relatively rotates the first line head unit about an axis orthogonal to the printing surface with respect to the printing surface.

[0077] Further, a printing method according to an aspect of the present invention uses an inkjet printing apparatus including: a first line head unit including a first base member and a plurality of first inkjet heads, the plurality of first inkjet heads being mounted on the first base member so as to be relatively rotatable about an axis orthogonal to the printing surface with respect to the first base member, and the plurality of first inkjet heads being linearly arranged with a plurality of nozzles; and a line head unit rotation mechanism unit that relatively rotates the first line head unit about an axis orthogonal to the printing surface with respect to the printing surface. The printing method includes the steps of: rotating the plurality of first inkjet heads so that a distance between the plurality of nozzles in a direction orthogonal to the moving direction of the printing surface becomes a distance corresponding to a specified definition; rotating the first line head unit by the line head unit rotation mechanism unit so that a distance between two adjacent first inkjet heads among the plurality of first inkjet heads in a direction orthogonal to the moving direction of the printing surface becomes a distance corresponding to a specified definition; 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 perform printing.

[0078] According to the inkjet printing apparatus and the printing method of the present invention, it is possible to suppress the number of components in an inkjet printing apparatus capable of arbitrarily adjusting the pitch of a plurality of nozzles.

[0079] Hereinafter, Embodiment 1 of the inkjet printing apparatus 1 of the present invention will be described with reference to the drawings.

[0080] (Embodiment 1)

[0081] Figure 1 is a plan view of a display panel 2 which is an object to be coated by the inkjet printing apparatus 1. As Figure 1 shown, red pixels 3a, blue pixels 3b, and green pixels 3c are repeatedly arranged on a substrate 3, and a pitch (Pp) corresponding to a Y-direction distance between pixels of the same color is constant within the substrate 3. The Y direction is Figure 1 the vertical direction. The plate surface of the substrate 3 is an example of a "printing surface".

[0082] Figure 2 is a schematic plan view of the inkjet printing apparatus 1 according to Embodiment 1. Figure 3It is a schematic top 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".

[0083] Use Figure 2 To describe the entire inkjet printing apparatus 1, use Figure 3 To describe the line head unit 20. It should be noted that in each figure, the printing direction is set as the X direction, and the width direction orthogonal to the printing direction is set as the Y direction. The printing direction is the same as the direction in which the printing surface moves. In addition, the front side and the back side of the paper surface in each figure are described as the upper and lower sides of the inkjet printing apparatus 1.

[0084] <Structure>

[0085] As Figure 2 shown, the inkjet printing apparatus 1 includes a platform 17, a substrate conveyance table 12 provided on the platform 17, head unit support portions 16 provided on both sides in the Y direction on the platform 17, and a line head unit 20 on the head unit support portions 16 by means of the line head unit Φ rotation mechanism 22.

[0086] It should be noted that the line head unit 20 is a line head unit distinguished by each ejected ink. For example, it is distinguished into a line head unit for red ink, a line head unit for blue ink, and a line head unit for green ink. Coating is performed in sequence.

[0087] The substrate conveyance table 12 includes: an X-axis guide 13 provided to extend in the X direction on the platform 17; an X-axis slider 9 supported on the X-axis guide 13 so as to be movable in the X direction; and a substrate adsorption worktable 11 mounted by means of a Yα drive mechanism (not shown) provided on the X-axis slider 9. Above the substrate adsorption worktable 11, a display panel 2 to be printed can be adsorbed and fixed parallel to the XY plane.

[0088] The position of the X-axis slider 9 is controlled by an X-axis slider control mechanism (not shown). Specifically, the X-axis slider control mechanism performs feedback control on the drive amount of the X-axis linear motor 14 that drives the X-axis slider 9 so that the detection result of the X-axis position detection mechanism 15 that detects the position of the X-axis slider 9 becomes the target position of the X-axis slider 9.

[0089] A Yα drive mechanism (not shown) moves the substrate adsorption table 11 relative to the X-axis slider 9 in the Y direction and rotates it about an axis orthogonal to the XY plane. Hereinafter, the direction about this axis is referred to as the α direction. The Yα drive mechanism is controlled by a Yα control mechanism (not shown). The Yα control mechanism controls the Yα drive mechanism based on the target position of the substrate adsorption table 11 in the Y direction and the target position in the α direction.

[0090] In addition, an alignment camera (not shown) for measuring the position of the display panel 2 in the X direction, the Y direction, and the α direction is provided on the stage 17.

[0091] As Figure 3 shown, the line head unit 20 includes a line head base 21 formed in a rectangular shape in plan view, a plurality of 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 head 24 is an example of a "first inkjet head" and a "second inkjet head".

[0092] The first ends of the respective inkjet heads 24a to 24j are connected to the fixed link 23a via a link rotation shaft member 23c so as to be relatively rotatable about the central axis of the link rotation shaft member 23c. In addition, the second ends of the respective inkjet heads 24a to 24j are connected to the movable link 23b via a link rotation shaft member 23c so as to be relatively rotatable about the central axis of the link rotation shaft member 23c. The fixed link 23a and the movable link 23b are arranged in parallel with each other. The respective inkjet heads 24a to 24j are arranged in parallel with each other and at equal intervals. That is, the respective 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 orthogonal to the printing surface of the display panel 2 (i.e., the plate surface of the substrate 3).

[0093] The fixed link 23a is fixed to the line head base 21 such that the length direction of the fixed link 23a is along the length direction of the line head base 21. The movable link 23b is arranged on the line head base 21 such that the length direction of the movable link 23b is along the length direction of the line head base 21 and the movable link 23b can move relatively parallel to the line head base 21.

[0094] Specifically, both end portions of the movable link 23b are connected to the θ-axis table 25a via the movable link lateral sliding guide 23g. Through the movable link lateral sliding guide 23g, the movable link 23b relatively moves with respect to the line head base 21 in a direction orthogonal to the length direction of the line head base 21. The θ-axis table 25a is disposed on the line head base 21 via the θ-axis guide 25g. Through the θ-axis guide 25g, the θ-axis table 25a relatively moves with respect to the line head base 21 along the length direction of the line head base 21. The θ-axis sliding mechanism 25 is constituted by the θ-axis table 25a and the θ-axis guide 25g.

[0095] In addition, the θ-axis table 25a is connected to a nut portion (not shown) fitted to the θ-axis ball screw 26s. The θ-axis ball screw 26s is connected to the θ-axis motor 26m. The θ-axis motor 26m is fixed to the line head base 21 via the θ-axis motor bracket 26b. By driving the θ-axis motor 26m, the θ-axis table 25a moves along the θ-axis guide 25g. The θ-axis drive unit 26 is constituted by the θ-axis motor 26m, the θ-axis ball screw 26s, and the θ-axis motor bracket 26b.

[0096] Moreover, a θ-axis position detection mechanism (not shown) for detecting the position of the θ-axis table 25a is mounted on the θ-axis table 25a. The position of the θ-axis table 25a is controlled by a θ-axis position control mechanism (not shown). Specifically, the θ-axis position control mechanism performs feedback control on the drive amount of the θ-axis motor 26m so that the detection result of the θ-axis position detection mechanism becomes the target position of the θ-axis table 25a. The inkjet head θ rotation mechanism 29 is constituted by the parallel link mechanism 23, the θ-axis sliding mechanism 25, and the θ-axis drive unit 26. By the movable link 23b performing parallel movement by means of the inkjet head θ rotation mechanism 29, the inkjet head 24 relatively rotates with respect to the line head base 21. The angle at which the inkjet head 24 rotates with respect to the X direction is denoted as the first angle θ. The first angle θ is the angle formed by the X direction and the length direction of the inkjet head 24. The inkjet head θ rotation mechanism 29 is an example of the "inkjet head rotation mechanism portion".

[0097] 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 rotation sliding mechanism 22r, and a Φ-axis lateral sliding guide 22g1. The line head Φ rotation shaft member 22c is disposed on the upper surface of one side of the head unit support portions 16 provided on both sides in the Y direction on the platform 17, and connects the head unit support portions 16 and the first end portion of the line head base 21. Through the line head Φ rotation shaft member 22c, the line head base 21 relatively rotates with respect to the head unit support portions 16 about the central axis of the line head Φ rotation shaft member 22c that is orthogonal to the XY plane. The central axis of the Φ rotation shaft member 22c is orthogonal to the printing surface of the display panel 2 (i.e., the plate surface of the substrate 3).

[0098] The Φ-axis guide member 22g2 is disposed on the upper surface of the other side of the head unit support portion 16, and causes the Φ-axis table 22t to move relative to the head unit support portion 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 member 22g1. Through the rotary sliding mechanism 22r, the Φ-axis lateral sliding guide member 22g1 rotates relative to the Φ-axis table 22t about an axis orthogonal to the XY plane and passing through the rotary sliding mechanism 22r. The second end portion of the line head base 21 is connected to the Φ-axis lateral sliding guide member 22g1. The second end portion is located at a position opposite to the first end portion with the plurality of inkjet heads 24 interposed therebetween. Through the Φ-axis lateral sliding guide member 22g1, the line head base 21 moves relative to the rotary sliding mechanism 22r in the direction in which the Φ-axis lateral sliding guide member 22g1 extends.

[0099] In addition, a Φ-axis motor 22m is mounted on the upper surface of the other side of the head unit support portion 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 portion (not shown) fitted to the Φ-axis ball screw 22s is connected to the Φ-axis table 22t. With this configuration, the Φ-axis motor 22m moves the Φ-axis table 22t in the X direction by rotation. On the other hand, the line head unit 20 rotates relative to the axis of the Φ-rotation shaft member 22c disposed on one side of the head unit support portion 16. That is, through the line head unit Φ-rotation mechanism 22, the line head unit 20 rotates relative to the head unit support portion 16. The angle of rotation of the line head unit 20 with respect to the Y direction is denoted as a second angle Φ. The second angle Φ is the angle formed by the Y direction and the longitudinal direction of the line head unit 20. In Figure 4 showing the inclination of the line head unit 20 becomes Figure 3 a schematic top view of the inkjet printing apparatus 1 of Embodiment 1 in the state shown.

[0100] In addition, the inkjet printing apparatus 1 includes an inkjet ejection control unit (not shown) that controls the ejection drive of each nozzle provided in all the inkjet heads 24 mounted on the line head unit 20. The inkjet ejection control unit can control the ejection timing of each nozzle based on the output signal of the X-axis position detection mechanism 15, the angle of the longitudinal direction of the inkjet head 24 with respect to the X direction (i.e., the first angle θ), and the angle of the longitudinal direction of the line head unit 20 with respect to the Y direction (i.e., the second angle Φ). Each nozzle ejects ink downward.

[0101] It should be noted that in Figure 3 it shows a state in which four nozzles 24a1 to 24a4 are linearly arranged in the inkjet head 24a. However, this is a simple illustration of the nozzle arrangement. In an actual inkjet head 24, as Figure 15AAs shown, 400 nozzles 24aA1 to 24aA400 are arranged at constant intervals along a linear A column. Additionally, 400 nozzles 24aB1 to 24aB400 are arranged at constant intervals along a linear B column. The A column and the B column are arranged parallel to each other. The A column and the B column are an example of a "nozzle column".

[0102] <Operation>

[0103] Next, the printing operation of the inkjet printing apparatus 1 having the above structure will be described.

[0104] (1) First, use Figures 5 to 8 to describe the operation of making the Y-direction pitch of all the nozzles arranged in the line head unit 20 coincide with the definition of clarity Pd of the display panel 2 to be printed.

[0105] Figure 5 is a top view showing the relationship between the nozzle positions and the printing object positions in the case of printing the display panel 2a having the first definition of clarity Pd in the inkjet printing apparatus 1 of the first embodiment. Figure 6 is a top view showing the relationship between the nozzle positions and the printing object positions in the case of printing the display panel 2b having the second definition of clarity Pd in the inkjet printing apparatus 1 of the first embodiment. Figure 7 is a top view showing the case where the nozzle positions and the printing object positions do not match in the case of printing the display panel 2c having the third definition of clarity Pd in the inkjet printing apparatus 1 of the first embodiment. Figure 8 is a top view showing the relationship between the nozzle positions and the printing object positions in the case of printing the display panel 2c having the third definition of clarity Pd in the inkjet printing apparatus 1 of the first embodiment.

[0106] In Figure 5 , Mp is the distance between the central axes of the link rotation shaft members 23c adjacent to each other in the fixed link 23a. MpΦ is the Y-direction distance of Mp and corresponds to the Y-direction interval between adjacent inkjet heads 24. MpΦ is represented by Equation (1). Φ is the second angle.

[0107] MpΦ = Mp × cos Φ Equation (1)

[0108] In addition, Np is the distance between adjacent nozzles in any inkjet head 24. θ is the first angle. Hp corresponds to the Y-direction distance between adjacent nozzles in one inkjet head 24. Hp is represented by Equation (2). The first angle θ is changed so as to coincide with Pp, which is the Y-direction distance between the same colors corresponding to the display panel 2, to adjust Hp. Hp can also change by more than twice before and after the relative rotation of the inkjet head 24 with respect to the line head base 21.

[0109] Hp = Np × sinθ Equation (2)

[0110] Here, in order to make the pitch in the Y direction of all the nozzles arranged in the line head unit 20 equal to Hp, Equation (3) needs to be satisfied. Therefore, MpΦ is adjusted by changing the second angle Φ based on Equation (1). N is the number of nozzles required for printing in any inkjet head 24 (details will be described later).

[0111] MpΦ = n × Hp Equation (3)

[0112] In addition, the area where ink is ejected onto the moving printing surface (printing width in the Y direction) is set as Pw. If the number of nozzles linearly arranged in one inkjet head 24 is set as Nn, then Pw is represented by Equation (4).

[0113] Pw = Nn × Hp Equation (4)

[0114] Figure 5 The state of the line head unit 20 shown indicates that Mp corresponding to the distance from the link rotation axis member 23c is n times the pitch (Pp) between the same colors of the display panel 2 (4 times in Figure 3 ), and the printing width (Pw) is consistent with Mp.

[0115] In addition, Figure 5 The first angle θ of the inkjet head 24 shown is the state where the pitch in the Y direction of all the nozzles arranged in the line head unit 20 can be made equal to Hp and is the minimum. That is, Figure 5 The first angle θ of the inkjet head 24 shown is the state where ink can be coated most clearly in one scan. When the first angle θ of the inkjet head 24 is smaller than the Figure 5 shown angle, there is a region where the pitch in the Y direction of all the nozzles arranged in the line head unit 20 is wider than Hp. Therefore, since printing cannot be performed in one scan, it is necessary to perform multiple scans repeatedly for printing.

[0116] In Figures 2 to 4 , only 4 nozzles are simply shown for one inkjet head 24, but as Figure 15A shown, among the nozzles of the inkjet head 24 actually used in Embodiments 1 to 3, 400 nozzles are arranged in each of Column A and Column B. In this embodiment, the nozzles in Column A of the two columns of Figure 15A are used. In addition, Figure 5 The first definition Pd of the display panel 2a shown is 440 ppi (pixels per inch). Hereinafter, the case of printing the display panel 2a using the line head unit 20 equipped with the Figure 15A inkjet head 24 will be described.

[0117] As Figure 15A shown, the inkjet head 24 is set such that Np = 0.16933333 mm (= 169.33333 μm), and Nn = 400 is set as described above. In addition, the line head unit 20 is set such that 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 deg, Hp = 57.727273 μm (Equation (2)).

[0118] At this time, Mp / Hp = 400, and Mp is an integer multiple of Hp. Therefore, by setting the second angle Φ to 0 deg in Equation (1), MpΦ = Mp, and Equation (3) holds. Therefore, the line head unit Φ rotation mechanism 22 is controlled so that the second angle Φ is 0 deg. At this time, n = 400.

[0119] In addition, at this time, according to Equation (4), Pw = 23090.90 μm. Therefore, Pw = Mp. In addition, since Equation (3) holds, the pitch in the Y direction of all the nozzles arranged in the line head unit 20 is equal to Hp.

[0120] When printing the display panel 2a using the line head unit 20 set in this way, the pitch (Pp) corresponding to the distance in the Y direction between the same colors of the display panel 2a is equal to Hp (that is, Pp = Hp = 57.72726 μm). Therefore, according to Equation (5), the definition Pd of the display panel 2a becomes 440 ppi, which corresponds to the first definition Pd.

[0121] Pd = 25400 / Pp Equation (5)

[0122] In addition, in this case, there are no nozzles adjacent to each other along the printing direction (X direction). That is, all the nozzles are used for printing. Since 400 nozzles are formed in the inkjet head 24 as described above, the number of nozzles used for printing in one inkjet head 24 is 400. In addition, this is represented by n shown in Equation (3). That is, n represents the number of nozzles required for printing in one inkjet head 24.

[0123] Next, Figure 6 is used to describe the case of printing the display panel 2b having the second definition Pd using the line head unit 20 in this embodiment. The second definition Pd is 220 ppi.

[0124] When the clarity Pd is 220 ppi, according to Equation (5), Pp = 115.454545 μm. To make Hp = Pp, according to Equation (2), θ is set to 42.98588 deg. Additionally, according to Equation (4), Pw = 46181.8 μm, so Pw / Mp = 2. Therefore, Mp / Hp = 200 (= n), and thus Mp is an integer multiple of Hp. Therefore, by setting the second angle Φ = 0 deg, Equation (3) is satisfied. In this case, the pitch in the Y direction of all the nozzles arranged in the line head unit 20 is equal to Hp. Thus, it is only necessary to control the inkjet head θ rotation mechanism 29 to position the inkjet head 24 at θ = 42.98588 deg and control the line head unit Φ rotation mechanism 22 to position the line head unit 20 at Φ = 0 deg.

[0125] It should be noted that in this case, since Pw / Mp = 2, the nozzles of the inkjet heads 24 adjacent to each other along the printing direction (X direction) are arranged as shown in Figure 6 . Therefore, even if ink is not ejected from one nozzle, the defective condition of one nozzle can be compensated by ejecting ink from the other nozzle. In other words, in one inkjet head 24, not all the nozzles need to be used for printing. In this case, the number of nozzles required for printing in one inkjet head 24 is n = 200.

[0126] As shown in Figure 6 , the regions Pw where two adjacent inkjet heads 24 among the multiple inkjet heads 24 eject ink onto the moving printing surface overlap with each other. For example, the printing region Pw1 of the inkjet head 24b overlaps with half of the printing region Pw2 of the inkjet head 24c. It should be noted that this is not limited thereto, and the printing region Pw1 of the inkjet head 24b may also overlap with more than half of the printing region Pw2 of the inkjet head 24c.

[0127] Next, use Figure 7 and Figure 8 to illustrate the case of printing on the display panel 2c with the third clarity Pd using the line head unit 20 in this embodiment. The third clarity Pd is 222 ppi.

[0128] When the clarity Pd is 222 ppi, according to Equation (5), Pp = 114.414414 μm. To make Hp = Pp, according to Equation (2), θ is set to 42.50665 deg. Additionally, in the case where the second angle Φ = 0 deg, according to Equation (4), Pw = 45765.76577 μm, so Pw / Mp = 1.9819812. Additionally, 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.

[0129] Here, the second angle Φ is adjusted so that Mp is an integer multiple of Hp. Hereinafter, the case where MpΦ is 201 times Hp, i.e., n = 201 in Equation (3), will be described. It is assumed that n = 201 because 201 is an integer that is smaller and closest to Mp / Hp (=201.8181) in the case where the second angle Φ = 0 deg.

[0130] In the case where n = 201, according to Equation (3), MpΦ = 201×Hp = 22997.29 μm. Here, since Mp = 23090.9 μm, according to Equation (1), the second angle Φ = 5.160897 deg.

[0131] It should be noted that the offset Δp in the Y direction of the nozzles of the inkjet head 24a and the nozzles of the inkjet head 24b in the state where the second angle Φ = 0 and the state where the second angle Φ = 5.160897 deg is expressed as follows. Figure 7 The offset Δp in the Y direction of the nozzles of the inkjet head 24a and the nozzles of the inkjet head 24b shown is expressed as follows.

[0132] Δp=(201.8181 - 201)×Hp = 93.60242 μm

[0133] Based on the above, the inkjet head θ rotation mechanism 29 is controlled to position the inkjet head 24 at θ = 42.50665 deg. In addition, the line head unit Φ rotation mechanism 22 is controlled to position the line head unit 20 at Φ = 5.1608970 deg ( Figure 8 ). Thus, the pitch in the Y direction of all the nozzles arranged in the line head unit 20 can be made consistent with Hp (=114.4144 μm). Therefore, since Pp = 114.414414 μm, the resolution Pd is 222 ppi. It should be noted that in this case, since n = 201, 201 nozzles are used for printing in one inkjet head 24.

[0134] As described above, as Figure 8 shown, by setting the first angle θ according to the resolution Pd of the display panel 2, the distance (Hp) in the Y direction between the multiple nozzles formed in one inkjet head 24 is adjusted. Moreover, by setting the second angle Φ according to the resolution Pd of the display panel 2, the interval in the width direction (Y direction) of the multiple inkjet heads 24 is adjusted. Thus, the pitch in the Y direction of all the nozzles arranged in the line head unit 20 can be made consistent with the resolution Pd of the display panel 2.

[0135] So far, the method for adjusting the nozzle pitch in the cases where the resolution Pd = 440 ppi, 220 ppi, and 222 ppi has been described. Here, in Figure 17A , Figure 17B , Figure 18A andFigure 18B The calculation results of the second angle Φ and the number of nozzles used for printing (hereinafter referred to as the number of nozzles used) are shown in the case of the definition Pd on the low-definition side (220 to 230 ppi) and the high-definition side (430 to 440 ppi).

[0136] Figure 17A It is a graph (low-definition side) showing the relationship between the definition Pd of the display panel 2 and the second angle Φ of the line head unit 20. Figure 17B It is a graph (low-definition side) showing the relationship between the definition Pd of the display panel 2 and the number of nozzles used of the inkjet head 24. Figure 18A It is a graph (high-definition side) showing the relationship between the definition Pd of the display panel 2 and the second angle Φ of the line head unit 20. Figure 18B It is a graph (high-definition side) showing the relationship between the definition Pd of the display panel 2 and the number of nozzles used of the inkjet head 24.

[0137] In Figure 17A , 17B , in the case where the definition Pd = 220 ppi (second definition 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 ).

[0138] When the definition Pd gradually increases from 220 ppi, the number of nozzles used remains 200, and the second angle Φ gradually increases. And, the definition Pd at the time when the number of nozzles used is 200 and the second angle Φ is around 6 deg is substantially the same as the definition Pd at the time when the number of nozzles used is 201 and the second angle Φ is 0. Thus, when the definition Pd increases, the number of nozzles used increases, and the second angle Φ repeatedly increases and decreases.

[0139] In addition, on the high-definition side, as shown in Figure 18A , 18B , it is also the same as the above-mentioned low-definition side Figure 17A , 17B . When the definition Pd increases, the number of nozzles used increases, and the second angle Φ repeatedly increases and decreases. On the high-definition side, for example, the definition Pd at the time when the number of nozzles used is 391 and the second angle Φ is around 4 deg is substantially the same as the definition Pd at the time when the number of nozzles used is 392 and the second angle Φ is 0. As described above, in the range where the definition Pd is 220 ppi to 440 ppi, the range of the second angle Φ being 0 to 6 deg is sufficient.

[0140] It should be noted that, as shown in Figure 17A , Figure 18AAs shown, the sharpness Pd at the second angle Φ = 0 exists every approximately 1 ppi. That is, every approximately 1 ppi, it is possible to print the sharpness Pd without rotating the line head unit 20.

[0141] It should be noted that in this embodiment, as the maximum sharpness Pd that can be coated in one scan, it is designed to be Figure 5 440 ppi, but since it is coated in multiple printing scans, as long as the condition is good, it is possible to handle a higher-resolution panel.

[0142] In addition, for the low sharpness side, an example where the sharpness Pd is 220 ppi is shown in Figure 6 , but in the setting where the sharpness Pd is 440 ppi shown in Figure 5 , by using every other nozzle in the Y direction, it is also possible to handle 220 ppi. In addition, in this case, by increasing the first angle θ and adjusting the second angle Φ, it is possible to handle up to 110 ppi. Moreover, in this case, by expanding the pitch of the nozzles used, it is possible to further reduce the sharpness Pd. In this way, by designing to be able to handle any sharpness Pd from 440 ppi to its half, 220 ppi, in the state where all nozzles are used, it is possible to handle any sharpness Pd below 440 ppi.

[0143] In addition, as shown in Figure 15A , in the inkjet head 24 used in this embodiment, column B is arranged at a position 8.0433 mm parallelly separated from column A. Column B is arranged with a stagger of 84.66667 μm in the direction along column A with respect to column A. Figure 15B It is a top view for explaining the minimum offset ΔY in the Y direction between the nozzles arranged in column A and the nozzles arranged in column B when the inkjet head 24 is tilted by the first angle θ.

[0144] In Figure 17C , 18C , the results obtained by calculating the offset ΔY on the low sharpness side (220 - 230 ppi) and the high sharpness side (430 - 440 ppi) are shown. In Figure 17C , 18C , in the case of the sharpness Pd where the offset ΔY = 0 shown at point 71, the nozzles in column A and the nozzles in column B are adjacent to each other along the printing direction (X direction).

[0145] In this way, when multiple columns are provided in the inkjet head 24 and the sharpness Pd with an offset ΔY of 0 is selected, it is not necessary to use all the nozzles in one column for printing. Therefore, it is possible to cope with the bad condition of not ejecting ink from the nozzles in another column, and thus it is possible to improve the operation rate of the inkjet printing apparatus 1.

[0146] (2) Next, use Figure 2 to describe the alignment method of the display panel 2.

[0147] The display panel 2 is adsorbed on the substrate adsorption workbench 11 and arranged parallel to the XY plane. Then, the positions of alignment marks, pixels, etc. (not shown) inside the display panel 2 are detected by an alignment camera (not shown). Moreover, a Yα drive mechanism (not shown) below the substrate adsorption workbench 11 is actuated to rotate the substrate adsorption workbench 11 so that the pixel arrangement is parallel to the printing direction (X direction).

[0148] Moreover, the relative positions of the nozzles and the substrate 3 in the X direction and the Y direction are measured and adjusted by the alignment camera. At this time, a line head unit 20 with a pre-adjusted first angle θ and second angle Φ is used to print on a test substrate (not shown). By measuring the pixels printed on the test substrate with the alignment camera, the positional relationship between the nozzles and the alignment camera is corrected. The alignment camera after correction is used to adjust the positional deviation between the pixels of the display panel 2 and the nozzle positions. In this case, for the positional deviation in the Y direction, it is adjusted by the Yα drive mechanism. In addition, for the positional deviation in the X direction, it is adjusted by the X-axis slider 9. It should be noted that by performing test printing with a combination of a single type of first angle θ and second angle Φ as described above and measuring the pixels with the alignment camera, the positional relationship between the alignment camera and the nozzles is confirmed.

[0149] Then, the first angle θ and the second angle Φ set based on the target sharpness Pd are input to the inkjet ejection control unit. The inkjet ejection control unit performs calculations based on the input first angle θ and second angle Φ so as to be able to eject at a timing such that the ejection timing of each nozzle coincides with the pixel position in the X direction of the display panel.

[0150] (3) Finally, use Figure 2 to describe the actual printing operation.

[0151] In Figure 2 the shown inkjet printing apparatus 1 is provided with a single line head unit 20. The above single line head unit 20 is configured to eject ink of one color. Therefore, in the case of printing three colors as in the Figure 1 shown display panel 2, in the inkjet printing apparatus 1, three line head units 20 that eject inks of different hues are arranged in a row along the printing direction (X direction).

[0152] For each of the three line head units 20, the adjustment of the nozzle pitch in the Y direction in the above (1) and the adjustment of the relative position between the display panel 2 to be printed and the nozzles in the above (2) are performed according to the hue. Then, the X-axis slider 9 is moved from Figure 2Scanned to the position indicated by the solid line Figure 2 the position indicated by the dashed line. At this time, the display panel 2 on the substrate adsorption workbench 11 passes under the inkjet heads 24 of the three line head units 20 at a constant speed.

[0153] 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 according to the ejection instructions sent from the inkjet ejection control unit. Thereby, the display panel with the target sharpness Pd is printed.

[0154] (Embodiment 2)

[0155] Next, use Figures 9 to 13 to describe Embodiment 2. The difference between Embodiment 2 and Embodiment 1 is that the inkjet printing apparatus 1 includes a plurality of line head units 20.

[0156] In Figure 9 the line head unit 20 of Embodiment 2 shown, the distance Mp between the link rotation shaft members 23c is set to Mp = 46181.82 μm (= 46.18182 mm), which is twice that of the above-mentioned Embodiment 1. When the width of the used inkjet head 24 is wide or when the link rotation shaft members 23c are made larger for more precision of the link rotation shaft members 23c, Mp is considered to be set larger. Other matters not described are the same as those in Embodiment 1.

[0157] In the case where Mp is set in this way, in order to cope with the sharpness Pd = 220 ppi (that is, Pp = Hp = 115.4545 μm), according to Equation (2), the first angle θ is set to 42.98588 deg.

[0158] In addition, Pw is Pw = 46181.82 μm (= 46.18182 mm) according to Equation (4). In this case, since Pw = Mp, all the nozzles of the inkjet head 24 are used for printing.

[0159] In this embodiment, when coping with a sharpness Pd higher than 220 ppi, the first angle θ is further reduced. In this case, in the region between adjacent inkjet heads 24, a region where the Y-direction pitch of the nozzles is wider than Hp appears.

[0160] Figure 10This is a diagram illustrating the case where the inkjet head 24 is rotated to handle 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 deg according to Equation (2). Moreover, the printing width Pw is Pw = 23090.90 μm (= 23.09090 mm). In this case, Pw = (1 / 2) × Mp and an unprinted area having the same width as Pw appears between adjacent inkjet heads 24 (the area where the pitch in the Y direction of the nozzles is wider than Hp). Figure 10 The shown areas 30a, 30c, 30e, 30g, 30i are printed areas. Additionally, areas 30b, 30d, 30f, 30h are unprinted areas.

[0161] In this case, as Figure 11 shown, a sub-line head unit 20B is arranged to supplement the area not printed by the main line head unit 20A. Thereby, the unprinted area can be prevented from occurring. 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".

[0162] The main line head unit 20A and the sub-line head unit 20B constitute a dual line head unit 43. Figure 11 This is used to explain the dual line head unit 43. Additionally, Figure 13 shows an inkjet printing apparatus 1 equipped with the dual line head unit 43.

[0163] <Structure>

[0164] In the present embodiment, a gantry for line head units 40 is provided. The gantry for line head units 40 rotates two line head units 20A, 20B simultaneously. Additionally, in the present embodiment, a gantry Φ rotation mechanism 42 and a line head unit transfer mechanism 50 for laterally moving the sub-line head unit 20B along the gantry for line head units 40 are further provided. The line head unit transfer mechanism 50 is an example of a "moving mechanism section".

[0165] First, the structure of the gantry Φ rotation mechanism 42 will be described. The gantry Φ rotation mechanism 42 includes a gantry Φ rotation shaft member 42c, a Φ axis guide 42g2, a Φ axis workbench 42t, a rotation sliding mechanism 42r, and a Φ axis lateral sliding guide 42g1.

[0166] The Φ-axis rotating shaft member 42c of the gantry is disposed on the upper surface of one side of the head unit support portions 16 provided on both sides of the platform 17. The Φ-axis rotating shaft member 42c of the gantry connects the head unit support portion 16 and the first end portion of the gantry 40 for the line head unit. Through the Φ-axis rotating shaft member 42c of the gantry, the gantry 40 for the line head unit relatively rotates with respect to the head unit support portion 16 about the central axis of the Φ-axis rotating shaft member 42c orthogonal to the XY plane.

[0167] The Φ-axis guide member 42g2 is disposed on the upper surface of the other side of the head unit support portion 16, and relatively moves the Φ-axis table 42t with respect to the head unit support portion 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 member 42g1. Through the rotary sliding mechanism 42r, the Φ-axis lateral sliding guide member 42g1 relatively rotates with respect to the Φ-axis table 42t about the axis orthogonal to the XY plane and passing through the rotary sliding mechanism 42r. The second end portion of the gantry 40 for the line head unit is connected to the Φ-axis lateral sliding guide member 42g1. Through the Φ-axis lateral sliding guide member 42g1, the gantry 40 for the line head unit relatively moves with respect to the rotary sliding mechanism 42r in the direction in which the Φ-axis lateral sliding guide member 42g1 extends.

[0168] In addition, the Φ-axis motor 42m is mounted on the upper surface of the other side of the head unit support portion 16 via the Φ-axis motor bracket 42b. The Φ-axis motor 42m is connected to the Φ-axis ball screw 42s, and a nut portion (not shown) fitted to the Φ-axis ball screw 42s is connected to the Φ-axis table 42t. With such a configuration, the Φ-axis motor 42m moves the Φ-axis table 42t in the X direction by rotation. On the other hand, the gantry 40 for the line head unit relatively rotates about the axis of the Φ-axis rotating shaft member 42c of the gantry disposed on one side of the head unit support portion 16. That is, through the gantry Φ-rotation mechanism 42, the gantry 40 for the line head unit is inclined with respect to the head unit support portion 16.

[0169] The sub-line head unit 20B is disposed on one side of the gantry 40 for the line head unit. The main line head unit 20A is disposed on the other side of the gantry 40 for the line head unit. Thus, by rotating the gantry 40 for the line head unit, the two line head units 20A and 20B rotate.

[0170] Next, the structure of the line head unit transfer mechanism 50 will be described. The line head unit transfer mechanism 50 moves the sub-line head unit 20B along the side surface of one side of the gantry 40 for the line head unit.

[0171] On one side of the gantry 40 for the line head unit, a line head unit transfer axis table 50t is arranged via a line head unit transfer axis guide 50g extending along the side of the gantry 40 for the line head unit. On the gantry 40 for the line head unit, a line head unit transfer axis motor bracket 50b is provided, and a line head unit transfer axis motor 50m is arranged via the 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.

[0172] In addition, the position of the line head unit transfer axis table 50t is controlled by a line head unit transfer axis control mechanism (not shown). Specifically, for the line head unit transfer axis table 50t, the line head unit transfer axis control mechanism performs feedback control on the driving amount of the line head unit transfer axis motor 50m so that the detection result of a line head unit transfer axis table position detection mechanism (not shown) that detects the position of the line head unit transfer axis table 50t becomes the target position of the line head unit transfer axis table 50t.

[0173] In addition, a sub-line head unit 20B is fixed to the line head unit transfer axis table 50t. On the other hand, a main line head unit 20A is fixed to the other side of the gantry 40 for the line head unit 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 gantry 40 for the line head unit along the line head unit transfer axis guide 50g.

[0174] <Operation>

[0175] Next, the printing operation of the inkjet printing apparatus 1 of the present embodiment will be described. The operation of the gantry Φ rotation mechanism 42 for adjusting 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 above-described Embodiment 1. Therefore, the adjustment of the nozzle position of the main line head unit 20A will be omitted, and the adjustment of the nozzle position of the sub-line head unit 20B will be described.

[0176] As described above, in the present embodiment, when dealing with a resolution Pd of 220 ppi or more, as Figure 11 shown, for the regions 30b, 30d, 30f, 30h, 30j that are not printed by the main line head unit 20A, supplementation by the sub-line head unit 20B is required.

[0177] Figure 11 It shows the pair with Figure 10A diagram showing the case where a display panel 2 with the same image resolution Pd, i.e., 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). Additionally, in this embodiment, since Mp = 46181.82 μm (= 46.18182 mm) is set, the printing width Pw = (1 / 2) × Mp. Therefore, as described above, an unprinted area appears between adjacent inkjet heads 24.

[0178] Moreover, since Mp = 800 × Hp, Mp is an integer multiple of Hp. Therefore, the second angle Φ is set to 0. Specifically, the second angle Φ is adjusted to 0 using the gantry Φ rotation mechanism 42. Additionally, for the inkjet head θ rotation mechanisms 29 of each line head unit 20A and 20B, the first angle θ is adjusted to 19.93227 deg.

[0179] 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 such that the regions 30b, 30d, 30f, 30h, 30j that can be printed by the sub - line head unit 20B correspond to the regions 30b, 30d, 30f, 30h, 30j that are not printed by the main line head unit 20A and the nozzle pitch in the Y - direction is the same. The adjustment of the position of the nozzles of the sub - line head unit 20B is performed as in Embodiment 1, by measuring the pixels printed on a test substrate using an alignment camera.

[0180] Next, Figure 12 a description will be given of the case where the image resolution Pd = 439.95 ppi. In Figure 12 it, a state is shown in which one less nozzle for printing is used in the inkjet head 24 of the sub - line head unit 20B. Since the actual number of nozzles of the inkjet head 24 used for printing is 400, 399 nozzles are used for printing.

[0181] In the case where the image resolution Pd = 439.95 ppi, according to Equation (5), Pp = Hp = 57.733833 μm. In this case, the printing width Pw of the main line head unit 20A is Pw = 23093.533 μm according to Equation (4). On the other hand, in the sub - line head unit 20B, since 399 nozzles are used for printing, the printing width Pw of the sub - line head unit 20B is Pw = 23035.799 μm. Therefore, the total printing width Pw after adding 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 coincides with MpΦ.

[0182] In this case, the second angle Φ is Φ = 2.731930 deg according to Equation (1). On the other hand, the first angle θ is θ = 19.934632 deg according to Equation (2). The console frame Φ rotation mechanism 42 and the inkjet head θ rotation mechanism 29 are set to the first angle θ and the second angle Φ calculated as such.

[0183] Moreover, as described above, the position of the sub-line head unit 20B is adjusted by the line head unit transfer mechanism 50. That is, it is adjusted so that the regions 30b, 30d, 30f, 30h, 30j that can be printed by the sub-line head unit 20B correspond to the regions 30b, 30d, 30f, 30h, 30j that are not printed by the main line head unit 20A and the nozzle pitch in the Y direction is the same. As a result, the definition Pd = 439.95 ppi.

[0184] So far, the method for adjusting the nozzle pitch in the case of the definition Pd = 440 ppi and 439.95 ppi has been described. Here, in Figure 19A , Figure 19B , Figure 20A and Figure 20B show the calculation results of the second angle Φ and the number of nozzles used by the inkjet head 24 of the sub-line head unit 20B in the case of the definition Pd on the low-definition side (220 - 230 ppi) and the high-definition side (430 - 440 ppi).

[0185] Figure 19A is a graph showing the relationship between the definition Pd of the display panel 2 and the second angle Φ of the line head unit 20 (low-definition side). Figure 19B is a graph showing the relationship between the definition Pd of the display panel 2 and the number of nozzles used by the sub-line head unit 20B (low-definition side). Figure 20A is a graph showing the relationship between the definition Pd of the display panel 2 and the second angle Φ of the line head unit 20 (high-definition side). Figure 20B is a graph showing the relationship between the definition Pd of the display panel 2 and the number of nozzles used by the sub-line head unit 20B (high-definition side).

[0186] In Figure 19A , in the case of the definition Pd = 220 ppi, the second angle Φ = 0. In addition, in Figure 19B , the number of nozzles used is 0. This case indicates that printing by the sub-line head unit 20B is not required.

[0187] When the definition Pd gradually increases from 220 ppi, the number of nozzles used is maintained at 200, and the second angle Φ gradually increases. Also, the definition Pd at the time when the number of nozzles used is 0 and the second angle Φ is around 4 deg is approximately the same as the definition Pd at the time when the number of nozzles used is one and the second angle Φ is 0. Thus, when the definition Pd increases, the number of nozzles used increases, and the second angle Φ repeatedly increases and decreases.

[0188] In addition, on the high-definition side, as Figure 20A , Figure 20B shows, it is also the same as the above-mentioned on the low-definition side Figure 19A , 19B that when the definition Pd increases, the number of nozzles used increases, and the second angle Φ repeatedly increases and decreases. On the high-definition side, for example, the definition Pd at the time when the number of nozzles used is 382 and the second angle Φ is around 3 deg is approximately the same as the definition Pd at the time when the number of nozzles used is 383 and the second angle Φ is 0. As described above, in the range where the definition Pd is 220 ppi to 440 ppi, a range of 0 to 4 deg for the second angle Φ is sufficient.

[0189] It should be noted that, as Figure 19A , Figure 20A shows, the second angle Φ = 0, that is, the definition Pd at which the line head unit 20 does not need to be rotated exists every approximately 0.5 ppi. In addition, when comparing Figure 19A with that in the case of the first embodiment Figure 17A , Figure 19A the period in which the second angle Φ = 0 in Figure 17A is approximately half of the period in which the second angle Φ = 0 in Figure 19C , 20C . This is because, in the first embodiment, the responsible section of 400 nozzles is adjusted in units of one nozzle, whereas in the case of the second embodiment, the responsible section of 800 nozzles is adjusted in units of one nozzle. In addition, in the second embodiment, the maximum value of the second angle Φ can be reduced relative to the first embodiment. The results of calculating the offset ΔY on the low-definition side (220 to 230 ppi) and the high-definition side (430 to 440 ppi) are shown in

[0190] (Third Embodiment)

[0191] Next, Figure 14 is used to describe the third embodiment. In order to adjust the first angle θ, the θ-axis drive unit 26 was used in the first embodiment. In contrast, in the third embodiment, both ends of the movable link 23b are driven by different drive shafts. Matters not described are the same as those in the first and second embodiments.

[0192] In this embodiment, a movable link R driving motor 27m is mounted on one side of the θ-axis table 25a via a movable link R driving motor bracket 27b. A movable link R driving ball screw 27s is connected to the movable link R driving motor 27m. The nut portion of the movable link R driving ball screw 27s is connected to one end portion of the movable link 23b. The movable link R driving motor 27m is controlled by a movable link R driving shaft control mechanism (not shown). The movable link R driving shaft control mechanism performs feedback control on the driving amount of the movable link R driving motor 27m so that the detection result of a movable link R driving shaft position detection mechanism (not shown) that detects the position of one end portion of the movable link 23b becomes the target position of one end portion of the movable link 23b.

[0193] On the other hand, a movable link L driving motor 28m is mounted on the other side of the θ-axis table 25a via a movable link L driving motor bracket 28b. A movable link L driving ball screw 28s is connected to the movable link L driving motor 28m. The nut portion of the movable link L driving ball screw 28s is connected to the other end portion of the movable link 23b. The movable link L driving motor 28m is controlled by a movable link L driving shaft control mechanism (not shown). The movable link L driving shaft control mechanism performs feedback control on the driving amount of the movable link L driving motor 28m so that the detection result of a movable link L driving shaft position detection mechanism (not shown) that detects the position of the other end portion of the movable link 23b becomes the target position of the other end portion of the movable link 23b. Moreover, by the movable link R driving shaft control mechanism and the movable link L driving shaft control mechanism, it is possible to make the moving amounts of one end portion and the other end portion of the movable link 23b the same.

[0194] When drive shafts are respectively arranged at both end portions of the movable link 23b as described above, compared with the case where one drive shaft is arranged as in the first embodiment, the movable link 23b can be driven with higher precision. Therefore, the inkjet head 24 can be rotated with higher precision.

[0195] It should be noted that in this embodiment, an inkjet head 24 having 400 nozzles formed in a single row as shown in Figure 15A is used, but instead of this, Figure 16A , 16BAn inkjet head 24 having 800 nozzles formed in a row as shown. When set to the first angle θ corresponding to the resolution Pd = 440 ppi, since the number of nozzles used is 400, there are nozzles in the inkjet head 24 having 800 nozzles formed in a row that are not used for printing. Additionally, at this time, in adjacent inkjet heads 24, there are nozzles adjacent to each other along the printing direction (X direction). Therefore, it is possible to cope with the defective condition where ink is not ejected from one of the nozzles of adjacent nozzles.

[0196] The condition for coping with this defective condition is represented by Equation (6). When the resolution Pd = 440 ppi, according to Equation (5), Pp = Hp = 57.72727 μm. When the number of nozzles formed in one inkjet head 24 is 800, according to Equation (4), Pw = 4681.818 μm. Additionally, Mp is set to 23090.909 μm. In this case, since Equation (6) is satisfied, there are nozzles that can cope with the defective condition of non - ejection of ink.

[0197] Pw≥2×Mp Equation (6)

[0198] It should be noted that in the present embodiment, link rotation shaft members 23c are respectively arranged at both ends of the inkjet head 24. Here, there are cases where the inkjet head 24 needs to be replaced due to nozzle clogging or the like. Therefore, the line head unit 20 may further include a mounting plate (not shown) capable of loading and unloading the inkjet head 24. In this case, the link rotation shaft members 23c are arranged at both ends of the mounting plate. The inkjet head 24 is mounted on the mounting plate in a manner that allows loading, unloading, and replacement. Additionally, the inkjet head 24 needs to be accurately positioned relative to the link rotation shaft members 23c. Therefore, the inkjet head 24 is mounted on the mounting plate using an expansion pin or the like.

[0199] It should be noted that for the line head unit 20 in the present embodiment, the number of inkjet heads 24 is 10. However, according to the method of the present invention, even if the number of inkjet heads 24 is further increased, the number of the line head unit Φ rotation mechanism 22 and the inkjet head θ rotation mechanism 29 for adjusting the rotation of the inkjet head 24 does not increase.

[0200] As described above, according to the inkjet printing apparatuses of Embodiments 1 to 3, even if the number of inkjet heads 24 used is increased to expand the width of the printing object, the mechanism for driving the inkjet heads 24 is not increased, and the pitch in the direction orthogonal to the printing direction of the nozzles can be arbitrarily adjusted.

[0201] [Industrial Applicability]

[0202] The inkjet printing device of the above solution of the present invention is effective for coating ink or the like on a printing object with a constant pitch in high definition, and can be applied to an inkjet printing device in printing an organic EL light-emitting body, a hole transport layer or an electron transport layer, or a color filter, etc.

Claims

1. An inkjet printing apparatus, wherein, the inkjet printing apparatus includes: a first line head unit including a first base member and a plurality of first inkjet heads, the plurality of first inkjet heads being mounted on the first base member so as to be integrally relatively rotatable about an axis orthogonal to a printing surface with respect to the first base member, and the plurality of first inkjet heads being linearly arranged with a plurality of nozzles and applying the same type of ink; and a line head unit rotation mechanism unit that relatively rotates the first line head unit about an axis orthogonal to the printing surface with respect to the printing surface.

2. An inkjet printing apparatus, wherein, the inkjet printing apparatus includes: a first line head unit including a first base member and a plurality of first inkjet heads, the plurality of first inkjet heads being mounted on the first base member so as to be relatively rotatable about an axis orthogonal to a printing surface with respect to the first base member, and the plurality of first inkjet heads being linearly arranged with a plurality of nozzles and applying the same type of ink; a line head unit rotation mechanism unit that relatively rotates the first line head unit about an axis orthogonal to the printing surface with respect to the printing surface; a second line head unit including a second base member and a plurality of second inkjet heads, the plurality of second inkjet heads being mounted on the second base member so as to be relatively rotatable about an axis orthogonal to the printing surface with respect to the second base member, and the plurality of second inkjet heads being linearly arranged with a plurality of nozzles and applying the same type of ink; and a moving mechanism unit that relatively moves the first line head unit with respect to the second line head unit in a direction intersecting the direction in which the printing surface moves.

3. An inkjet printing apparatus, wherein, the inkjet printing apparatus includes: a first line head unit including a first base member and a plurality of first inkjet heads, the plurality of first inkjet heads being mounted on the first base member so as to be relatively rotatable about an axis orthogonal to a printing surface with respect to the first base member, and the plurality of first inkjet heads being linearly arranged with a plurality of nozzles and applying the same type of ink; and a line head unit rotation mechanism unit that relatively rotates the first line head unit about an axis orthogonal to the printing surface with respect to the printing surface, the first line head unit further includes a connecting member that connects one end of each of the plurality of first inkjet heads, the first base member, the plurality of first inkjet heads, and the connecting member constitute a parallel link mechanism.

4. The inkjet printing apparatus according to claim 3, wherein, the first line head unit further includes an inkjet head rotation mechanism unit that relatively rotates the plurality of first inkjet heads with respect to the first base member by relatively moving the connecting member with respect to the first base member.

5. An inkjet printing apparatus, wherein, the inkjet printing apparatus includes: A first line head unit including a first base member and a plurality of first inkjet heads, wherein the plurality of first inkjet heads are mounted on the first base member so as to be relatively rotatable about an axis orthogonal to the printing surface with respect to the first base member, and the plurality of first inkjet heads are linearly arranged with a plurality of nozzles and apply the same type of ink; and a line head unit rotation mechanism unit that relatively rotates the first line head unit about an axis orthogonal to the printing surface with respect to the printing surface, Regions where 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 Regions where the two first inkjet heads that apply the same type of ink eject ink onto the moving printing surface overlap by more than half.

7. The inkjet printing apparatus according to claim 5 or 6, 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 able to be located at positions along the direction of movement of the printing surface.

8. An inkjet printing apparatus, wherein The inkjet printing apparatus includes: A first line head unit including a first base member and a plurality of first inkjet heads, wherein the plurality of first inkjet heads are mounted on the first base member so as to be relatively rotatable about an axis orthogonal to the printing surface with respect to the first base member, and the plurality of first inkjet heads are linearly arranged with a plurality of nozzles and apply the same type of ink; and a line head unit rotation mechanism unit that relatively rotates the first line head unit about an axis orthogonal to the printing surface with respect to the printing surface, The inkjet printing apparatus is configured such that a distance between two adjacent nozzles arranged in one of the plurality of first inkjet heads along the direction in which the plurality of first inkjet heads are arranged can change by more than twice before and after the relative rotation of the plurality of first inkjet heads with respect to the first base member.

9. An inkjet printing apparatus, wherein The inkjet printing apparatus includes: A first line head unit including a first base member and a plurality of first inkjet heads, wherein the plurality of first inkjet heads are mounted on the first base member so as to be relatively rotatable about an axis orthogonal to the printing surface with respect to the first base member, and the plurality of first inkjet heads are linearly arranged with a plurality of nozzles and apply the same type of ink; and a line head unit rotation mechanism unit that relatively rotates the first line head unit about an axis orthogonal to the printing surface with respect to the printing surface, A plurality of nozzle arrays each composed of the plurality of nozzles are arranged in the plurality of first inkjet heads respectively, Nozzles arranged in one of the plurality of nozzle arrays and nozzles arranged in the other of the plurality of nozzle arrays are configured to be able to be located at positions along the direction of movement of the printing surface.

10. An inkjet printing apparatus, wherein The inkjet printing apparatus includes: A first line head unit includes a first base member and a plurality of first inkjet heads. The plurality of first inkjet heads are mounted on the first base member so as to be relatively rotatable about an axis orthogonal to the printing surface with respect to the first base member, and the plurality of first inkjet heads are linearly arranged with a plurality of nozzles and apply the same type of ink. And A line head unit rotation mechanism portion that relatively rotates the first line head unit about an axis orthogonal to the printing surface with respect to the printing surface. The first line head unit further includes a mounting plate for detachably mounting the plurality of first inkjet heads. The plurality of first inkjet heads are mounted on the first line head unit via the mounting plate.

11. A printing method, wherein the printing method uses an inkjet printing apparatus including: A first line head unit includes a first base member and a plurality of first inkjet heads. The plurality of first inkjet heads are mounted on the first base member so as to be integrally relatively rotatable about an axis orthogonal to the printing surface with respect to the first base member, and the plurality of first inkjet heads are linearly arranged with a plurality of nozzles and apply the same type of ink. And A line head unit rotation mechanism portion that relatively rotates the first line head unit about an axis orthogonal to the printing surface with respect to the printing surface. The printing method includes the following steps: Integrally rotating the plurality of first inkjet heads so that the distance between the plurality of nozzles in a direction orthogonal to the moving direction of the printing surface becomes a distance corresponding to a specified image definition. Rotating the first line head unit by the line head unit rotation mechanism portion so that the distance between two adjacent first inkjet heads among the plurality of first inkjet heads in a direction orthogonal to the moving direction of the printing surface becomes a distance corresponding to the specified image definition. 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 perform printing.

12. A printing method, wherein the printing method uses an inkjet printing apparatus including: A first line head unit includes a first base member and a plurality of first inkjet heads. The plurality of first inkjet heads are mounted on the first base member so as to be relatively rotatable about an axis orthogonal to the printing surface with respect to the first base member, and the plurality of first inkjet heads are linearly arranged with a plurality of nozzles and apply the same type of ink. And A line head unit rotation mechanism portion that relatively rotates the first line head unit about an axis orthogonal to the printing surface with respect to the printing surface. The printing method includes the following steps: Rotating the plurality of first inkjet heads so that the distance between the plurality of nozzles in a direction orthogonal to the moving direction of the printing surface becomes a distance corresponding to a specified image definition. Rotate the first line head unit by using the line head unit rotation mechanism unit so that the distance between two adjacent first inkjet heads among the plurality of first inkjet heads in a direction orthogonal to the moving direction of the printing surface becomes a distance corresponding to the specified definition; Move the printing surface relative to the first line head unit, and eject ink from the plurality of nozzles toward the printing surface to perform printing; And Rotate the first line head unit by using the line head unit rotation mechanism unit so that, among two adjacent first inkjet heads among the plurality of first inkjet heads, the nozzles of the first inkjet head arranged on one side and the nozzles of the first inkjet head arranged on the other side are located at positions along the moving direction of the printing surface.

13. A printing method, wherein The printing method uses an inkjet printing device, and the inkjet printing device includes: A first line head unit, which includes a first base member and a plurality of first inkjet heads. The plurality of first inkjet heads are mounted on the first base member so as to be able to relatively rotate around an axis orthogonal to the printing surface with respect to the first base member, and the plurality of first inkjet heads are linearly arranged with a plurality of nozzles and apply the same type of ink; And A line head unit rotation mechanism unit, which relatively rotates the first line head unit around an axis orthogonal to the printing surface with respect to the printing surface, The printing method includes the following steps: Rotate the plurality of first inkjet heads so that the distance between the plurality of nozzles in a direction orthogonal to the moving direction of the printing surface becomes a distance corresponding to the specified definition; Rotate the first line head unit by using the line head unit rotation mechanism unit so that the distance between two adjacent first inkjet heads among the plurality of first inkjet heads in a direction orthogonal to the moving direction of the printing surface becomes a distance corresponding to the specified definition; And Move the printing surface relative to the first line head unit, and eject ink from the plurality of nozzles toward the printing surface to perform printing, A plurality of nozzle arrays composed of the plurality of nozzles are respectively arranged on the plurality of first inkjet heads, The printing method further includes the following step: Rotate the first line head unit by using the line head unit rotation mechanism unit so that the nozzles arranged in one nozzle array among the plurality of nozzle arrays and the nozzles arranged in the other nozzle array among the plurality of nozzle arrays are located at positions along the moving direction of the printing surface.

14. The inkjet printing device according to claim 4, wherein The inkjet head rotation mechanism unit includes a first motor, and the first motor relatively moves the connection member with respect to the first base member.

15. An inkjet printing device, wherein The inkjet printing device includes: A first line head unit having a first base member and a plurality of first inkjet heads, the plurality of first inkjet heads being mounted on the first base member so as to be relatively rotatable about an axis orthogonal to the printing surface with respect to the first base member, and the plurality of first inkjet heads being linearly arranged with a plurality of nozzles and applying the same type of ink; A line head unit rotation mechanism unit that relatively rotates the first line head unit about an axis orthogonal to the printing surface with respect to the printing surface; And A platform The first base member has a first end portion and a second end portion located at a position opposite to the first end portion with the plurality of first inkjet heads interposed therebetween; The first end portion is rotatably supported by the platform; The line head unit rotation mechanism unit includes a second motor that rotates the first base member about the first end portion by moving the second end portion relative to the platform.

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