Liquid ejecting device

Abstract

To improve printing accuracy.SOLUTION: A liquid jet device 1 includes a liquid jet head 10 which has a jet surface F1 having a first nozzle array NLA for jetting first ink, and a second nozzle array NLB for jetting second ink, and can hold the liquid jet head in a first posture in which the jet surface F1 inclines with respect to a horizontal plane F0. Viscosity of the first ink is higher than viscosity of the second ink. The first nozzle array NLA is positioned above the second nozzle array NLB in a gravity direction G1 in the first posture.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a liquid ejecting apparatus and a liquid ejecting head. [Background technology]

[0002] In a recording head that ejects a plurality of types of ink, the ejection surface that ejects the ink may be inclined with respect to the horizontal plane (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-34170 A Summary of the Invention [Problem to be solved by the invention]

[0004] The viscosity of ink may differ depending on the type of ink. In the conventional technology, the relationship between the effect of the ink having different viscosities and the effect of the ink ejection surface being tilted is not taken into consideration. [Means for solving the problem]

[0005] A liquid ejection device according to one aspect of the present invention includes a liquid ejection head having an ejection surface including a first nozzle row for ejecting a first ink and a second nozzle row for ejecting a second ink, and is capable of holding the liquid ejection head in a first position in which the ejection surface is inclined with respect to a horizontal plane. The viscosity of the first ink is higher than the viscosity of the second ink. In the first position, the first nozzle row is located above the second nozzle row in the direction of gravity.

[0006] A liquid ejecting apparatus according to one aspect of the present invention includes a first ejection unit including a first nozzle that ejects a first ink. a first liquid ejection head having a projection surface and a second ejection surface including a second nozzle for ejecting a second ink; A second liquid ejection head having the above, and is provided with. The viscosity of the first ink is higher than the viscosity of the second ink. higher. The angle formed between the direction in which the first ink is ejected from the first nozzles and the gravitational direction is the first angle. Is it a loop? The first liquid ejection head is arranged so that the angle formed between the direction in which the first ink is ejected from the first nozzles and the gravitational direction is the first angle, and the angle formed between the direction in which the second ink is ejected from the second nozzles and the gravitational direction is the second angle, which is larger than the first angle. The second liquid ejection head is arranged so that the angle formed between the direction in which the second ink is ejected from the second nozzles and the gravitational direction is the second angle, which is larger than the first angle. The liquid ejection head according to one aspect of the present invention includes a first nozzle row for ejecting a first ink, a second nozzle row for ejecting a second ink, and a third nozzle row for ejecting a third ink. The viscosity of the third ink is lower than the viscosity of the first ink and higher than the viscosity of the second ink. The third nozzle row is located between the first nozzle row and the second nozzle row with respect to the gravitational direction. The third nozzle row is located between the first nozzle row and the second nozzle row with respect to the gravitational direction.

[0007]

Brief Description of the Drawings

Brief Description of the Drawings

[0008]

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Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, in each figure, the dimensions and scales of each part may be appropriately different from the actual ones. Further, since the embodiments described below are preferred specific examples of the present invention, various technically preferable limitations are imposed. However, the scope of the present invention is not limited to these embodiments unless otherwise specifically stated to limit the present invention in the following description.

[0010] In the following description, there may be cases where three mutually intersecting directions are described as the X-axis direction, the Y-axis direction, and the Z-axis direction. The X-axis direction includes the X1 direction and the X2 direction which are opposite directions to each other. The X-axis direction is an example of the first direction. The Y-axis direction includes the Y1 direction and the Y2 direction which are opposite directions to each other. The Y-axis direction is an example of the second direction. The Z-axis direction includes the Z1 direction and the Z2 direction which are opposite directions to each other. The X-axis direction, the Y-axis direction, and the Z-axis direction are orthogonal. Note that the X-axis direction, the Y-axis direction, and the Z-axis direction are directions based on the injection surface F1 described later.

[0011] Also, the downward direction of the gravity direction is defined as the gravity direction G1, and the direction orthogonal to both the gravity direction G1 and the X-axis direction is described as the K-axis direction. Also, the direction opposite to the gravity direction G1 is defined as the upward direction G2. The K-axis direction includes the K1 direction and the K2 direction which are opposite directions to each other. The K-axis direction is an example of the third direction. The K-axis direction is an example of the horizontal direction. The horizontal direction is a direction orthogonal to the gravity direction G1. The third direction is a direction orthogonal to both the first direction and the gravity direction G1.

[0012] FIG. 1 is a schematic diagram showing a liquid injection device 1 according to the first embodiment. FIG. 2 is a block diagram showing an ink flow path. The liquid injection device 1 is an inkjet printing device that injects ink, which is an example of "liquid", as droplets onto a medium PA. The liquid injection device 1 is a so-called line-type printing device in which a plurality of nozzles for injecting ink are distributed over the entire range in the width direction of the medium PA. The medium PA is typically printing paper. Note that the medium PA is not limited to printing paper, and may be a printing target of any material such as a resin film or a fabric, for example.

[0013] The liquid injection device 1 includes a liquid injection head 10 having an injection surface F1 inclined with respect to the horizontal plane F0. The liquid injection device 1 includes a plurality of liquid containers 2, a control unit 3, a medium conveyance mechanism 4, an ink supply unit 5, and the liquid injection head 10. The liquid injection device 1 may include one liquid injection head 10 or may include a plurality of liquid injection heads 10. The liquid injection device 1 of the present embodiment includes one liquid injection head 10. When a plurality of liquid injection heads 10 are provided, the plurality of liquid injection heads 10 are arranged in the X-axis direction to form a line head.

[0014] The control unit 3 controls the operations of the respective elements of the liquid injection device 1. The control unit 3 includes, for example, a processing circuit such as a CPU or an FPGA, and a storage circuit such as a semiconductor memory. Various programs and various data are stored in the storage circuit. The processing circuit realizes various controls by executing the program and appropriately using the data. CPU is an abbreviation for Central Processing Unit. FPGA is an abbreviation for Field Programmable Gate Array.

[0015] The medium conveyance mechanism 4 is controlled by the control unit 3 and conveys the medium PA in the conveyance direction DM. The conveyance direction DM is the conveyance direction of the medium PA at a position facing the injection surface F1 and is parallel or substantially parallel to the Y-axis direction. The medium conveyance mechanism 4 includes a long conveyance roller along the width direction of the medium PA and a motor for rotating the conveyance roller. Note that the medium conveyance mechanism 4 is not limited to a configuration using a conveyance roller, and for example, a configuration using a drum or an endless belt that conveys the medium PA in a state where it is adsorbed to the outer peripheral surface by an electrostatic force or the like may also be used.

[0016] A medium conveyance path 4a for conveying the medium PA is formed in the liquid injection device 1. The medium conveyance path 4a is a path from the paper feed unit 4b to the paper discharge unit 4c. The medium conveyance mechanism 4 conveys the medium PA along the medium conveyance path 4a. The paper feed unit 4b and the paper discharge unit 4c include trays capable of storing the medium PA.

[0017] The liquid container 2 stores ink. Specific examples of the liquid container 2 include, for example, a cartridge that is detachable from the liquid ejecting apparatus 1, an ink pack in a bag shape formed of a flexible film, and an ink tank that can be refilled with ink. Note that the type of ink stored in the liquid container 2 is arbitrary.

[0018] The liquid container 2 includes liquid containers 2A, 2B, 2C, and 2D. The first ink is stored in the liquid container 2A. The second ink is stored in the liquid container 2B. The third ink is stored in the liquid container 2C. The fourth ink is stored in the liquid container 2D. For example, the first ink, the second ink, the third ink, and the fourth ink are inks of different colors. The viscosities of these first ink, second ink, third ink, and fourth ink are different from each other. The viscosity of the first ink is higher than the viscosity of the second ink. The viscosity of the third ink is lower than the viscosity of the first ink and higher than the viscosity of the second ink. The viscosity of the fourth ink is lower than the viscosity of the third ink and higher than the viscosity of the second ink. The components for each type of ink will be described later.

[0019] The difference between the viscosity of the first ink and the viscosity of the second ink is 0.5 mPa·S or more. At 25°C, the viscosity of the first ink is higher than the viscosity of the second ink. At 25°C, the viscosities of the first to fourth inks are high in the order of the first ink, the third ink, the fourth ink, and the second ink. Note that the temperature at which the viscosities of the inks are compared may be higher than 25°C or lower than 25°C, and it is preferable to compare at the temperature of the ink in the actually used liquid ejecting head 10.

[0020] The ink supply unit 5 includes ink flow paths 6 and 7 that supply ink from the liquid container 2 to the liquid ejection head 10, and a pressure adjustment unit 8 that adjusts the pressure of the ink within the liquid ejection head 10. The ink flow path 6 includes a flow path extending from the liquid container 2 to the pressure adjustment unit 8. The ink flow path 7 includes a flow path extending from the pressure adjustment unit 8 to the liquid ejection head 10. The ink flow path 7 includes a flow path formed within the liquid ejection head 10. The ink flow paths 6 and 7 are formed, for example, by piping or tubes. The ink flow paths 6 and 7 include, for example, flow path members such as grooves, recesses, through holes, etc., as well as piping and tubes.

[0021] The pressure adjustment unit 8 adjusts the pressure of the ink supplied to the liquid ejection head 10 so that a predetermined pressure acts on the nozzle N. The pressure adjustment unit 8 is, for example, a negative pressure generation unit that includes a pressure adjustment valve. This negative pressure generation unit has, for example, a pressure adjustment valve that opens and closes the ink flow path, and a flexible member that deflects based on the differential pressure between the pressure in the ink flow path downstream of the pressure adjustment valve and the atmospheric pressure, and controls the opening and closing of the pressure adjustment valve by moving the pressure adjustment valve due to the deflection of this flexible member so that a predetermined range of negative pressure acts on the nozzle N.

[0022] Alternatively, the pressure adjustment unit 8 may adjust the pressure of the ink supplied to the liquid ejection head 10 by a sub-tank that temporarily stores the ink. Specifically, the pressure adjustment unit 8 has a sub-tank and an arbitrary sensor capable of detecting the storage amount of the ink within the sub-tank. When the storage amount of the ink within the sub-tank detected by the sensor decreases below the threshold value, ink is replenished from the liquid container 2 to keep the storage amount of the ink within the sub-tank substantially constant, that is, to keep the liquid level of the ink stored within the sub-tank substantially constant, and thereby adjust the pressure of the ink within the liquid ejection head 10 based on the head difference between the liquid level within the sub-tank and the liquid ejection head 10. Also, the pressure within the sub-tank may be set to a predetermined pressure by a compressor to adjust the pressure of the ink supplied to the liquid ejection head 10.

[0023] The pressure adjustment unit 8 includes pressure adjustment units 8A, 8B, 8C, and 8D. The pressure adjustment unit 8A communicates with the liquid container 2A and adjusts the pressure of the first ink. The pressure adjustment unit 8B communicates with the liquid container 2B and adjusts the pressure of the second ink. The pressure adjustment unit 8C communicates with the liquid container 2C and adjusts the pressure of the third ink. The pressure adjustment unit 8D communicates with the liquid container 2D and adjusts the pressure of the fourth ink. The pressure adjustment units 8A, 8B, 8C, and 8D can maintain the pressures of the first ink, the second ink, the third ink, and the fourth ink at the same pressure.

[0024] FIG. 3 is a bottom view showing the nozzle plate 11 on which the nozzle rows NL are formed. The liquid ejection head 10 includes a nozzle plate 11 having a plurality of nozzle rows NL. The nozzle row NL includes a plurality of nozzles N for ejecting ink. Among the surfaces of the nozzle plate 11, the surface facing the medium PA is the ejection surface F1 for ejecting ink. A plurality of nozzles N are formed on the ejection surface F1. The ejection surface F1 is arranged at a distance from the medium PA.

[0025] The plurality of nozzle rows NL include nozzle rows NLA, NLB, NLC, and NLD. The nozzle row NLA includes a plurality of nozzles N for ejecting the first ink. The nozzle row NLB includes a plurality of nozzles N for ejecting the second ink. The nozzle row NLC includes a plurality of nozzles N for ejecting the third ink. The nozzle row NLD includes a plurality of nozzles N for ejecting the fourth ink. When not distinguishing the nozzle rows NLA, NLB, NLC, and NLD, they may be described as the nozzle row NL.

[0026] The nozzle row NL includes a plurality of nozzles N arranged in the X-axis direction. The nozzle N is a through hole penetrating in the plate thickness direction of the nozzle plate 11. The plate thickness direction of the nozzle plate 11 is along the Z-axis direction. The nozzle rows NLA, NLB, NLC, and NLD are arranged at different positions in the Y-axis direction.

[0027] In the direction of the Y1 axis, the nozzle rows NLA, NLC, NLD, and NLB are arranged in this order. The nozzle rows NLA, NLC, NLD, and NLB are spaced apart from each other in the Y-axis direction. The nozzle row NLC is arranged between the nozzle row NLA and the nozzle row NLB in the Y-axis direction. The nozzle row NLD is arranged between the nozzle row NLC and the nozzle row NLB in the Y-axis direction.

[0028] When viewed in the Y-axis direction, at least a part of the nozzle rows NLA, NLC, NLD, and NLB overlap. In the present embodiment, when viewed in the Y-axis direction, the nozzle rows NLA, NLC, NLD, and NLB all overlap.

[0029] As shown in FIG. 1, the liquid ejection head 10 is held in an inclined posture with respect to the housing 1a of the liquid ejection device 1, for example. Note that "the liquid ejection head 10 is held with respect to the housing 1a of the liquid ejection device 1" includes both the case where the liquid ejection head 10 is directly fixed and held with respect to the housing 1a, and the case where the liquid ejection head 10 is indirectly held with respect to the housing 1a via a member different from the housing 1a. The liquid ejection device 1 can hold the liquid ejection head 10 in an inclined posture in which the ejection surface F1 is inclined with respect to the horizontal plane F0.

[0030] FIG. 4 is a schematic view showing the liquid ejection head 10 in an inclined posture in which the ejection surface F1 is inclined with respect to the horizontal plane F0. As shown in FIG. 4, the ejection surface F1 of the liquid ejection head 10 is inclined at an inclination angle θ1 with respect to the horizontal plane F0. The inclination angle θ1 is, for example, an acute angle less than 90 degrees. The inclination angle θ1 may be an obtuse angle exceeding 90 degrees. The inclination angle θ1 may be 90 degrees. The inclination here includes 90 degrees. The inclined posture of the liquid ejection head 10 in which the ejection surface F1 is inclined at the inclination angle θ1 with respect to the horizontal plane F0 is an example of the first posture.

[0031] In the inclined posture of the liquid ejection head 10 shown in FIG. 4, the plurality of nozzle rows NL are arranged at different heights with respect to the gravitational direction G1. The nozzle row NLA is arranged at the height position HA, and the nozzle row NLB is arranged at the height position HB. The height position HA is located above the height position HB. That is, the nozzle row NLA that ejects the first ink having a higher viscosity is located above the nozzle row NLB that ejects the second ink having a lower viscosity.

[0032] The nozzle row NLC is arranged at the height position HC. The height position HC is below the height position HA and above the height position HB. In the inclined posture of the liquid ejection head 10, the nozzle row NLC is located below the nozzle row NLA and above the nozzle row NLB. That is, among the first ink, the second ink, and the third ink, the nozzle row NLC that ejects the third ink having the second highest viscosity is arranged between the nozzle row NLA and the nozzle row NLB with respect to the gravitational direction G1.

[0033] The nozzle row NLD is arranged at the height position HD. The height position HD is below the height position HC and above the height position HB. In the inclined posture of the liquid ejection head 10, the nozzle row NLD is located below the nozzle row NLC and above the nozzle row NLB. That is, among the second ink, the third ink, and the fourth ink, the nozzle row NLD that ejects the fourth ink having the second highest viscosity is arranged between the nozzle row NLC and the nozzle row NLB with respect to the gravitational direction G1.

[0034] As shown in FIG. 4, when viewed in the X-axis direction, the nozzle rows NLA, NLC, NLD, and NLB are arranged at intervals from each other.

[0035] When comparing the plurality of nozzle rows NL, the nozzle row NL that ejects the ink having a higher viscosity is located above the nozzle row NL that ejects the ink having a lower viscosity.

[0036] Next, with reference to FIGS. 5 to 7, due to factors such as circulation cleaning (not shown) that cause an abnormality in the pressure adjustment unit 8 and circulate the ink in the flow path within the liquid ejection head 10, the meniscus of the nozzle N becomes positive pressure, and the behavior of the ink droplets 101 and 102 ejected from the nozzle N and the satellite droplet 101a separated from the ink droplet 101 will be described. Here, the nozzle plates 11 and 111 of a liquid ejection head that ejects two types of inks with different viscosities will be exemplified and described. In FIGS. 5 and 6, the nozzle plate 111 according to Comparative Example 1 is shown, and in FIG. 7, the nozzle plate 11 according to Example 1 is shown. In the nozzle plate 111 according to Comparative Example 1, the nozzle row NLB that ejects the second ink with a lower viscosity is located above the nozzle row NLA that ejects the first ink with a higher viscosity. In the nozzle plate 11 according to Example 1, contrary to the case of Comparative Example 1, the nozzle row NLA that ejects the first ink is located above the nozzle row NLB that ejects the second ink.

[0037] FIG. 5 is a cross-sectional view showing a state in which the ink droplets 101 and 102 are overflowing from the nozzles NA and NB of the nozzle plate 111 according to Comparative Example 1. In the state shown in FIG. 5, the ink droplet 102, which is the second ink, is overflowing from the upper nozzle row NLB, and the ink droplet 101, which is the first ink, is overflowing from the lower nozzle row NLA.

[0038] FIG. 6 is a cross-sectional view showing the nozzle plate 111 according to Comparative Example 1, and is a view showing a state in which the ink droplet 101 overflowing from the nozzle NA is dripping along the ejection surface F1. In the state shown in FIG. 6, the ink droplet 102 is moving in the Y1 direction along the ejection surface F1. The ink droplet 101 overflowing from the lower nozzle row NLA exists in front of the nozzle NA. The front of the nozzle NA is outside the nozzle NA and is the position in the Z1 direction of the nozzle NA. The ink droplet 102 with a lower viscosity is more likely to drip downward by gravity than the ink droplet 101 with a higher viscosity. The ink droplet 102 moves in the Y1 direction and approaches the lower ink droplet 101. As time passes, the ink droplet 102 moves in the Y1 direction, contacts the ink droplet 101, and the ink droplet 102 and the ink droplet 101 are mixed together.

[0039] In this state, when the first ink is ejected from the nozzle row NLA, the first ink mixed with the second ink lands on the medium PA. Therefore, there is a possibility that the printing accuracy may decrease.

[0040] FIG. 7 is a cross-sectional view showing the nozzle plate 11 according to the first embodiment, and shows a state where ink droplets 101 and 102 are overflowing from the nozzles NA and NB. In the state shown in FIG. 7, the ink droplet 102 is moving in the Y1 direction along the ejection surface F1. In this case, the ink droplet 101 overflowing from the upper nozzle row NLA remains at the position in front of the nozzle NA. The upper ink droplet 101 does not approach the lower nozzle row NLB. The ink droplet 102 oozing out from the lower nozzle row NLB moves downward by gravity, but the ink droplet 102 does not approach the ink droplet 101. The ink droplet 101 and the ink droplet 102 do not mix. Thus, since the nozzle row NLA that ejects the first ink having a higher viscosity is located above the nozzle row NLB with respect to the gravitational direction G1, in the first embodiment, color mixing between the first ink and the second ink can be suppressed.

[0041] In the liquid ejection head 10 according to the first embodiment shown in FIG. 4, the nozzle rows NLA, NLB, NLC, and NLD are arranged according to the viscosity of the ink. The nozzle row NLA that ejects the first ink having the highest viscosity is arranged at a higher position with respect to the gravitational direction G1 than the other nozzle rows NLB, NLC, and NLD. Thus, since the nozzle row NLA that ejects the first ink that is least likely to drip is arranged at a high position, the first ink is prevented from mixing with the other second ink, third ink, and fourth ink.

[0042] In the liquid ejection head 10, the nozzle row NLB that ejects the second ink having the lowest viscosity is arranged at a lower position with respect to the gravitational direction G1 than the other nozzle rows NLA, NLC, and NLD. Thus, since the nozzle row NLB that ejects the second ink that is most likely to drip is arranged at a low position, the second ink is prevented from mixing with the other first ink, third ink, and fourth ink.

[0043] In the liquid ejection head 10, among a plurality of types of inks, the nozzle row for ejecting the first ink with a higher viscosity is positioned above the nozzle row for ejecting the second ink with a lower viscosity with respect to the gravitational direction G1, so that mixing of the inks is suppressed. As a result, improvement in printing accuracy in the liquid ejection apparatus 1 can be achieved. Compared with the configuration of Comparative Example 1 in which the nozzle row NL for ejecting the second ink with a lower viscosity is arranged at a higher position than the nozzle row NL for ejecting the first ink with a higher viscosity, in the liquid ejection head 10, the possibility of mixing of the plurality of inks is low.

[0044] In the liquid ejection head 10, the nozzle row NLC is positioned between the nozzle row NLA and the nozzle row NLB with respect to the gravitational direction G1. The viscosity of the third ink ejected from the nozzle row NLC is lower than the viscosity of the first ink and higher than the viscosity of the second ink. On the ejection surface F1, the upper first ink is less likely to drip, so the possibility of adhering to the lower third ink is low. On the ejection surface F1, since the second ink exists below, the possibility of the second ink adhering to the upper third ink is small.

[0045] In the liquid ejection head 10, the nozzle row NLD is positioned between the nozzle row NLC and the nozzle row NLB with respect to the gravitational direction G1. The viscosity of the fourth ink ejected from the nozzle row NLD is lower than the viscosity of the third ink and higher than the viscosity of the second ink. On the ejection surface F1, the upper third ink is relatively less likely to drip, so the possibility of adhering to the lower fourth ink is low. On the ejection surface F1, since the second ink exists below, the possibility of the second ink adhering to the upper fourth ink is small.

[0046] For example, when the ejection surface F1 is inclined, if the ink that is more likely to drip exists above there is a risk that the ink drips and mixes with the lower ink. In the liquid ejection apparatus 1, the viscosity of the first ink supplied to the nozzle row NLA arranged above is such that the nozzle row N arranged below Higher than the viscosity of the second ink supplied to the LB. As a result, the ink that is less likely to drip will be 1 placed upward, preventing mixing of multiple types of inks.

[0047] Next, with reference to FIG. 8, the inclined posture of the liquid ejection head 10 according to Example 2 will be described. FIG. 8 is a schematic view showing the liquid ejection head 10 according to Example 2, and is a view showing an inclined posture in which the ejection surface F1 is inclined so as to face obliquely upward. The difference between the liquid ejection head 10 of Example 2 shown in FIG. 8 and the liquid ejection head 10 of the first embodiment shown in FIG. 4 is that the inclination angle θ2 of the ejection surface F1 is different from the inclination angle θ1.

[0048] The inclination angle θ2 is an obtuse angle greater than 90 degrees with respect to the horizontal plane F0. The inclination angle θ2 is a rotation angle counterclockwise in the figure around the rotation axis along the X-axis direction. In FIG. 8, the ejection surface F1 is inclined so as to face obliquely upward. The liquid ejection head 10 according to such Example 2 exhibits the same effects as the liquid ejection head 10 according to the above-described first embodiment.

[0049] Next, with reference to FIG. 9, the inclined posture of the liquid ejection head 10 according to Example 3 will be described. FIG. 9 is a schematic view showing the liquid ejection head 10 according to Example 3, and is a view showing a posture in which the ejection surface F1 is perpendicular to the horizontal plane F0. The difference between the liquid ejection head 10 of Example 3 shown in FIG. 9 and the liquid ejection head 10 of the first embodiment shown in FIG. 4 is that the angle θ3 of the ejection surface F1 is different from the inclination angle θ1. Note that the inclined posture of the liquid ejection head 10 may include a posture perpendicular to the horizontal plane F0. In the present embodiment, there may be a case where the ejection surface F1 is inclined when it is perpendicular to the horizontal plane F0. The angle θ3 forms 90 degrees with respect to the horizontal plane F0 and is a right angle. The liquid ejection head 10 according to such Example 3 exhibits the same effects as the liquid ejection head 10 according to the above-described first embodiment, and can reduce variations in the ease of ink supply and suppress variations in ink ejection characteristics in a plurality of nozzle rows.

[0050] Next, with reference to FIG. 10, the attitude change of the liquid ejection head 10 according to Example 4 will be described. FIG. 10 is a schematic view showing the liquid ejection head 10 according to Example 4. In FIG. 10, the liquid ejection head 10 in the first attitude P1 in which the ejection surface F1 is inclined with respect to the horizontal plane F0 is illustrated by a solid line, and the liquid ejection head 10 in the second attitude P2 arranged such that the ejection surface F1 is along the horizontal plane F0 is indicated by a broken line. The liquid ejection head 10 can rotate and move around a rotation axis S1 extending in the X-axis direction.

[0051] The attitude of the liquid ejection head 10 can be changed to a plurality of attitudes including the first attitude P1 and the second attitude P2. The liquid ejection device 1 according to Example 4 has an attitude change mechanism 13 for changing the attitude of the liquid ejection head 10. The attitude change mechanism 13 includes a bearing 14 that holds a rotation axis S1 extending in the X-axis direction, and a drive mechanism 15 that rotates the rotation axis S1. The bearing 14 rotatably supports the rotation axis S1. The drive mechanism 15 includes, for example, a motor.

[0052] Note that in the first attitude P1 and the second attitude P2, the rotation axis S1 may be present at the same position or at different positions. In the attitude change of the liquid ejection head 10 from the first attitude P1 to the second attitude P2, the liquid ejection head 10 may include a linear movement. The liquid ejection device 1 can linearly move the bearing 14 that holds the rotation axis S1. For example, it can be linearly moved by a rack and pinion. The liquid ejection head 10 can be linearly moved using other ball screws, guide grooves, actuators, belt mechanisms, etc.

[0053] Next, with reference to FIG. 11, the liquid ejection head 10 according to Example 5 will be described. FIG. 11 is a schematic view showing the liquid ejection head 10 of the liquid ejection apparatus 1 according to Example 5 and a cap 22 that covers the ejection surface F1 of the liquid ejection head 10. The liquid ejection apparatus 1 can perform a maintenance operation. The liquid ejection apparatus 1 performs a maintenance operation in the second posture P2 of the liquid ejection head 10. The liquid ejection apparatus 1 performs a printing operation in the first posture P1 shown in FIG. 10 and a maintenance operation in the second posture P2 shown in FIG. 11.

[0054] The liquid ejection apparatus 1 includes a cap 22, a pipe 23, and a pump 24 that are used for a maintenance operation. The cap 22 covers the ejection surface F1 of the liquid ejection head 10. The cap 22 is arranged so as to cover the openings of the nozzles N in the plurality of nozzle rows NL. A space 22a for receiving the ink ejected from the nozzles N is formed in the cap 22.

[0055] A pipe 23 is connected to the cap 22. The pipe 23 is a pipe for discharging the ink present in the space 22a of the cap 22. A pump 24 is connected to the pipe 23. By driving the pump 24, the ink in the cap 22 can be sucked and discharged outside the cap 22.

[0056] Examples of the maintenance operation of the liquid ejection apparatus 1 include a flushing process, a suction cleaning process, and a pressure cleaning process. These maintenance operations are executed in the second posture P2 of the liquid ejection head 10. In the flushing process, by applying a pressure fluctuation to the pressure chamber communicating with the nozzle N using the actuator of the liquid ejection head 10, the ink that does not contribute to the recording operation is ejected from the nozzle N. In the suction cleaning process, for example, the pump 24 is used to suck the ink from the nozzle N. Further, in the pressure cleaning process, the ink flow path in the liquid ejection head 10 may be pressurized from upstream of the pressure chamber using a pump or the like (not shown) to discharge the ink from the nozzle N.

[0057] In this way, in the liquid ejection device 1, by performing maintenance processing, unnecessary ink in the nozzle N can be discharged to the outside of the liquid ejection head 10. In the second posture P2 of the liquid ejection head 10, the ejection surface F1 is parallel to the horizontal plane F0. In the liquid ejection device 1, since the maintenance operation can be performed in this second posture P2, the remaining amount of ink in the cap 22 can be reduced during air suction. For example, when the liquid ejection head 10 is in the first posture P1, the cap 22 is inclined, so ink remains in the corner portion 22c in the cap 22. On the other hand, in the present embodiment, since the maintenance operation is performed with the bottom surface 22b of the cap 22 arranged along the horizontal plane F0, the ink remaining in the cap 22 can be reduced. When performing the maintenance operation in an inclined posture, there is a risk of ink leakage from the seal portion during capping. The seal portion during capping includes the portion where the cap 22 and the ejection surface F1 are in contact.

[0058] Next, with reference to the component table shown in FIG. 12, the components of the ink will be described. Hereinafter, unless otherwise specified, "parts" and "%" regarding the component amounts are based on mass.

[0059] <Adjustment of Pigment Dispersion Liquid> To a solution prepared by dissolving 5.0 g of concentrated hydrochloric acid in 5.5 g of water, 1.6 g of 4-amino-1,2-benzenedicarboxylic acid was added at a temperature of 5°C. To maintain the temperature at 10°C or lower, a solution prepared by dissolving 1.8 g of sodium nitrite in 9.0 g of water was added to the solution obtained above while stirring with an ice bath. After stirring for 15 minutes, the specific surface area was 220 m 26.0 g of carbon black having a DBP oil absorption of 105 mL / 100 g and being / g was added and then mixed. Further, after stirring for 15 minutes, the obtained slurry was filtered through filter paper, the carbon black was thoroughly washed with water, and dried in an oven at 110 °C. Water was added to the obtained carbon black to obtain a pigment dispersion liquid in a state where a self-dispersing pigment having -C6H3-(COONa)2 groups bonded to the particle surface of the carbon black was dispersed in water (the pigment content was 15.0%). Then, using the ion exchange method, the sodium ions in the pigment dispersion liquid were replaced with potassium ions. The pigment dispersion liquid was used for the preparation of the first ink having a black hue.

[0060] <Adjustment of liquid containing dye> As dye 1, a liquid containing C.I. Direct Blue 199, as dye 2, a liquid containing C.I. Acid Red 289, and as dye 3, a liquid containing C.I. Direct Yellow 132 were obtained, respectively, and a liquid containing dyes 1 to 3 (the dye content was 10.0%). The liquid containing dye 1 was used for the preparation of the second ink having a cyan hue. The liquid containing dye 2 was used for the preparation of the third ink having a magenta hue. The liquid containing dye 3 was used for the preparation of the fourth ink having a yellow hue.

[0061] <Adjustment of ink> Each component shown in the table shown in FIG. 12 was mixed and stirred thoroughly. Then, it was pressure-filtered through a cellulose acetate filter (manufactured by Advantec) with a pore size of 1.2 μm to prepare an ink. The viscosity η of the ink at 25 °C is described in the lower part of the table. The viscosity η of the ink was measured using a rotational viscometer (RE80 type viscometer, manufactured by Toki Sangyo Co., Ltd.). In addition, the viscosity of the ink may be measured with a viscometer (trade name "RE80 type viscometer", manufactured by Toki Sangyo Co., Ltd.). Acetylenol E100 is a nonionic surfactant manufactured by Kawaken Fine Chemicals.

[0062] Next, with reference to FIG. 13, the arrangement of the nozzle rows NL of the liquid ejection head 10B according to Modification 1 will be described. FIG. 13 is a bottom view showing the ejection surface 11B of the liquid ejection head 10B according to Modification 1. The liquid ejection head 10B has a plurality of nozzle rows NL. The nozzle rows NL include nozzle rows NLA1, NLA2, NLA3 for ejecting the first ink, nozzle rows NLB1, NLB2, NLB3 for ejecting the second ink, nozzle rows NLC1, NLC2, NLC3 for ejecting the third ink, and nozzle rows NLD1, NLD2, NLD3 for ejecting the fourth ink. When not distinguishing between the nozzle rows NLA1, NLA2, NLA3, NLB1, NLB2, NLB3, NLC1, NLC2, NLC3, NLD1, NLD2, NLD3, they may be referred to as the nozzle row NL.

[0063] The liquid ejection head 10B has a plurality of head chips 12. A nozzle plate having nozzles N formed thereon is provided on the head chip 12. A nozzle row NL for ejecting one type of ink is provided on the head chip 12. The head chip 12 has a pressure chamber and an actuator (not shown). The actuator raises the pressure of the ink in the pressure chamber to eject the ink from the nozzles N.

[0064] The nozzle rows NLA1, NLA2, NLA3 are arranged at different positions in the X-axis direction. The nozzle rows NLA1, NLA 3 and the nozzle row NLA 2 are arranged at different positions in the Y-axis direction. The nozzle row NLA2 is located in the Y2 direction with respect to the nozzle rows NLA1, NLA3. In the first posture P1 of the liquid ejection head 10B, the nozzle row N LA2 is located above the nozzle rows NLA1, NLA3 with respect to the gravity direction G1. In the first posture P1, the ejection surface F2 is in a state inclined with respect to the horizontal plane. In the first posture P1, the ejection surface F2 is in a state inclined with respect to the horizontal plane.

[0065] The arrangement of nozzle rows NLB1, NLB2, and NLB3 is the same as that of nozzle rows NLA1, NLA2, and NLA3. The nozzle rows NLB1, NLB2, and NLB3 are spaced apart from the nozzle rows NLA1, NLA2, and NLA3 in the Y-axis direction.

[0066] The arrangement of nozzle rows NLC1, NLC2, and NLC3 is the same as that of nozzle rows NLA1, NLA2, and NLA3. The nozzle rows NLC1, NLC2, and NLC3 are located between the nozzle rows NLA1, NLA2, and NLA3 and the nozzle rows NLB1, NLB2, and NLB3 in the Y-axis direction.

[0067] The arrangement of nozzle rows NLD1, NLD2, and NLD3 is the same as that of nozzle rows NLA1, NLA2, and NLA3. The nozzle rows NLD1, NLD2, and NLD3 are located between the nozzle rows NLC1, NLC2, and NLC3 and the nozzle rows NLB1, NLB2, and NLB3 in the Y-axis direction.

[0068] The liquid ejecting device 1 may be provided with a liquid ejecting head 10B instead of the liquid ejecting head 10. The liquid ejecting device 1 provided with the liquid ejecting head 10B has the same operational effects as the liquid ejecting device 1 provided with the above-described liquid ejecting head 10.

[0069] Next, with reference to FIG. 14, the arrangement of the nozzle rows NL of the liquid ejecting head 10C according to Modification 2 will be described. FIG. 14 is a bottom view showing the ejection surface F3 of the liquid ejecting head 10C according to Modification 2. The liquid ejecting head 10C has a plurality of nozzle rows NL. The nozzle rows NL include a nozzle row NLA that ejects the first ink, a nozzle row NLB that ejects the second ink, a nozzle row NLC that ejects the third ink, and a nozzle row NLD that ejects the fourth ink. When the nozzle rows NLA, NLB, NLC, and NLD are not distinguished, they may be referred to as the nozzle row NL.

[0070] The liquid ejection head 10C has a plurality of head chips 12C. The head chip 12C is provided with a nozzle plate 11C on which nozzles N are formed. The head chip 12C is provided with nozzle rows NLA, NLB, NLC, and NLD, respectively.

[0071] FIG. 14 shows the V-axis direction and the W-axis direction that are orthogonal to each other. The V-axis direction and the W-axis direction are orthogonal to the Z-axis direction. The V-axis direction and the W-axis direction are directions based on the ejection surface F3. The V-axis direction includes the V1 direction and the V2 direction. The W-axis direction includes the W1 direction and the W2 direction. The V-axis direction intersects the X-axis direction at an inclination angle α.

[0072] The plurality of nozzle rows NL extend along the V-axis direction. The nozzles N included in the nozzle row NL are arranged in the V-axis direction. The nozzle row NLA and the nozzle row NLD are arranged in the V-axis direction. The nozzle row NLA and the nozzle row NLD are spaced apart in the V-axis direction. The nozzle row NLA and the nozzle row NL D are spaced apart in the Y-axis direction. FIG. 1 4 shows virtual lines L3 and L4 illustrated by a two-dot chain line are. The virtual lines L3 and L4 are lines that are spaced apart from each other in the Y-axis direction and extend along the X-axis direction. The virtual line L3 is located in the Y2 direction of the virtual line L4. The nozzle rows NLA and NLC are also located in the Y2 direction from the virtual line L3, and the nozzle rows NLB and NLD are located in the Y1 direction from the virtual line L4 .

[0073] The nozzle row NLC and the nozzle row NLB are arranged in the V-axis direction. The nozzle row NLC and the nozzle row NLB are spaced apart in the V-axis direction. The nozzle row NLC and the nozzle row NLB are spaced apart in the Y-axis direction. In the liquid ejection head 10C, the nozzle rows NLA and NLC are an example of the first nozzle row, and the nozzle rows NLD and NLB are an example of the second nozzle row.

[0074] When viewed in the Y-axis direction, at least a part of the nozzle row NLA overlaps with the nozzle rows NLD and NLB. For example, among two head chips 12C adjacent to each other in the X-axis direction, the one arranged in the X1 direction is defined as the head chip 12C1, and the one arranged in the X2 direction of the head chip 12C1 is defined as the head chip 12C2. The nozzle row NLA of the head chip 12C1 and the nozzle rows NLD and NLB of the head chip 12C2 overlap at least partially when viewed in the Y-axis direction. Note that the nozzle row NLA and the nozzle rows NLD and NLB within the same head chip 12 may overlap at least partially in the Y-axis direction.

[0075] Similarly, when viewed in the Y-axis direction, at least a part of the nozzle row NLC overlaps with the nozzle rows NLD and NLB. The nozzle row NLC of the head chip 12C1 and the nozzle rows NLD and NLB of the head chip 12C2 overlap at least partially when viewed in the Y-axis direction. Note that the nozzle row NLC and the nozzle rows NLD and NLB within the same head chip 12 may overlap at least partially in the Y-axis direction.

[0076] When viewed in the X-axis direction, the nozzle row NLA and the nozzle rows NLD and NLB are arranged with a gap in the Y-axis direction. When viewed in the X-axis direction, the nozzle row NLC and the nozzle rows NLD and NLB are arranged with a gap in the Y-axis direction.

[0077] Regarding the Y-axis direction, the distance between the nozzle row NLA and the nozzle row NLC provided in the same head chip 12C is narrower than the distance between the nozzle row NLC provided in the head chip 12C1 and the nozzle row NLA provided in the head chip 12C2.

[0078] The nozzle NA1 located at the upper end of the nozzle row NLA with respect to the gravity direction G1 is located above the nozzle ND1 located at the upper end of the nozzle row NLD and the nozzle NB1 located at the upper end of the nozzle row NLB with respect to the gravity direction G1.

[0079] The nozzle NC1 located at the upper end of the nozzle row NLC with respect to the gravity direction G1 is located above the nozzle ND1 located at the upper end of the nozzle row NLD and the nozzle NB1 located at the upper end of the nozzle row NLB with respect to the gravity direction G1.

[0080] The liquid ejecting apparatus 1 including such a liquid ejecting head 10C exhibits the same operational effects as the liquid ejecting apparatus 1 including the above-described liquid ejecting head 10.

[0081] In the liquid ejecting head 10C including nozzle rows NL that at least partially overlap each other with respect to the gravity direction G1, when considering the problem that a plurality of types of ink droplets drip and mix along the ejection surface F3 as described above, the nozzles N located at the same position on the X-axis, which is the extending direction of the intersection line between the ejection surface F3 in the inclined posture and the horizontal plane F0, are compared to determine the height relationship between the nozzle rows NL that at least partially overlap each other. This is because, since the intersection line between the ejection surface F3 in the inclined posture and the horizontal plane F0 extends along the X-axis, the ink overflowing from the nozzle N tends to drip in the Y1 direction on the ejection surface F3 due to the action of gravity. The X-axis is an example of a virtual axis along the extending direction of the intersection line between the ejection surface F in the inclined posture and the horizontal plane F0. In the liquid ejecting head 10C including nozzle rows NL that at least partially overlap each other with respect to the gravity direction G1, when considering the problem that a plurality of types of ink droplets drip and mix along the ejection surface F3 as described above, the nozzles N located at the same position on the X-axis, which is the extending direction of the intersection line between the ejection surface F3 in the inclined posture and the horizontal plane F0, are compared to determine the height relationship between the nozzle rows NL that at least partially overlap each other. This is because, since the intersection line between the ejection surface F3 in the inclined posture and the horizontal plane F0 extends along the X-axis, the ink overflowing from the nozzle N tends to drip in the Y1 direction on the ejection surface F3 due to the action of gravity. The X-axis is an example of a virtual axis along the extending direction of the intersection line between the ejection surface F in the inclined posture and the horizontal plane F0. In the liquid ejecting head 10C including nozzle rows NL that at least partially overlap each other with respect to the gravity direction G1, when considering the problem that a plurality of types of ink droplets drip and mix along the ejection surface F3 as described above, the nozzles N located at the same position on the X-axis, which is the extending direction of the intersection line between the ejection surface F3 in the inclined posture and the horizontal plane F0, are compared to determine the height relationship between the nozzle rows NL that at least partially overlap each other. This is because, since the intersection line between the ejection surface F3 in the inclined posture and the horizontal plane F0 extends along the X-axis, the ink overflowing from the nozzle N tends to drip in the Y1 direction on the ejection surface F3 due to the action of gravity. The X-axis is an example of a virtual axis along the extending direction of the intersection line between the ejection surface F in the inclined posture and the horizontal plane F0. In the liquid ejecting head 10C including nozzle rows NL that at least partially overlap each other with respect to the gravity direction G1, when considering the problem that a plurality of types of ink droplets drip and mix along the ejection surface F3 as described above, the nozzles N located at the same position on the X-axis, which is the extending direction of the intersection line between the ejection surface F3 in the inclined posture and the horizontal plane F0, are compared to determine the height relationship between the nozzle rows NL that at least partially overlap each other. This is because, since the intersection line between the ejection surface F3 in the inclined posture and the horizontal plane F0 extends along the X-axis, the ink overflowing from the nozzle N tends to drip in the Y1 direction on the ejection surface F3 due to the action of gravity. The X-axis is an example of a virtual axis along the extending direction of the intersection line between the ejection surface F in the inclined posture and the horizontal plane F0. In the liquid ejecting head 10C including nozzle rows NL that at least partially overlap each other with respect to the gravity direction G1, when considering the problem that a plurality of types of ink droplets drip and mix along the ejection surface F3 as described above, the nozzles N located at the same position on the X-axis, which is the extending direction of the intersection line between the ejection surface F3 in the inclined posture and the horizontal plane F0, are compared to determine the height relationship between the nozzle rows NL that at least partially overlap each other. This is because, since the intersection line between the ejection surface F3 in the inclined posture and the horizontal plane F0 extends along the X-axis, the ink overflowing from the nozzle N tends to drip in the Y1 direction on the ejection surface F3 due to the action of gravity. The X-axis is an example of a virtual axis along the extending direction of the intersection line between the ejection surface F in the inclined posture and the horizontal plane F0. In the liquid ejecting head 10C including nozzle rows NL that at least partially overlap each other with respect to the gravity direction G1, when considering the problem that a plurality of types of ink droplets drip and mix along the ejection surface F3 as described above, the nozzles N located at the same position on the X-axis, which is the extending direction of the intersection line between the ejection surface F3 in the inclined posture and the horizontal plane F0, are compared to determine the height relationship between the nozzle rows NL that at least partially overlap each other. This is because, since the intersection line between the ejection surface F3 in the inclined posture and the horizontal plane F0 extends along the X-axis, the ink overflowing from the nozzle N tends to drip in the Y1 direction on the ejection surface F3 due to the action of gravity. The X-axis is an example of a virtual axis along the extending direction of the intersection line between the ejection surface F in the inclined posture and the horizontal plane F0. In the liquid ejecting head 10C including nozzle rows NL that at least partially overlap each other with respect to the gravity direction G1, when considering the problem that a plurality of types of ink droplets drip and mix along the ejection surface F3 as described above, the nozzles N located at the same position on the X-axis, which is the extending direction of the intersection line between the ejection surface F3 in the inclined posture and the horizontal plane F0, are compared to determine the height relationship between the nozzle rows NL that at least partially overlap each other. This is because, since the intersection line between the ejection surface F3 in the inclined posture and the horizontal plane F0 extends along the X-axis, the ink overflowing from the nozzle N tends to drip in the Y1 direction on the ejection surface F3 due to the action of gravity. The X-axis is an example of a virtual axis along the extending direction of the intersection line between the ejection surface F in the inclined posture and the horizontal plane F0. In the liquid ejecting head 10C including nozzle rows NL that at least partially overlap each other with respect to the gravity direction G1, when considering the problem that a plurality of types of ink droplets drip and mix along the ejection surface F3 as described above, the nozzles N located at the same position on the X-axis, which is the extending direction of the intersection line between the ejection surface F3 in the inclined posture and the horizontal plane F0, are compared to determine the height relationship between the nozzle rows NL that at least partially overlap each other. This is because, since the intersection line between the ejection surface F3 in the inclined posture and the horizontal plane F0 extends along the X-axis, the ink overflowing from the nozzle N tends to drip in the Y1 direction on the ejection surface F3 due to the action of gravity. The X-axis is an example of a virtual axis along the extending direction of the intersection line between the ejection surface F in the inclined posture and the horizontal plane F0. 3 The X-axis is an example of a "virtual axis along the extending direction of the intersection line between the ejection surface F in the inclined posture and the horizontal plane F0".

[0082] Also, the problem of color mixing due to ink dripping is likely to occur within the same head chip 12C. In this modified example, within the same head chip 12C, the nozzle row NLA and the nozzle row NLC at least partially overlap each other with respect to the gravity direction G1, and the nozzle row NLB and the nozzle row NLD at least partially overlap each other with respect to the gravity direction G1.

[0083] Here, the nozzle rows located at the same position within the same head chip 12C and on the X-axis When comparing nozzle NA of NLA with nozzle NC of nozzle row NLC, when the said nozzle NA of nozzle row NLA is located above the said nozzle NC of nozzle row NL C , it is preferable that nozzle row NLA is a nozzle row above nozzle row NLC. Similarly, when comparing nozzle ND of nozzle row NLD located at the same position on the X-axis within the same print head chip 12C with nozzle NB of nozzle row NLB, when the said nozzle ND of nozzle row NLD is located above the said nozzle NB of nozzle row NL , it is preferable that nozzle row NLD is a nozzle row above nozzle row NL . Thus, nozzle row NLB. In this way, nozzle row NLA can be taken as an example of the first nozzle row, nozzle row NLB can be taken as an example of the second nozzle row, nozzle row NLC can be taken as an example of the third nozzle row, and nozzle row NLD can be taken as an example of the fourth nozzle row.

[0084] Next, with reference to FIG. 15, the arrangement of nozzle rows NL of the liquid ejection head 10D according to Modification 3 will be described. FIG. 15 is a bottom view showing the ejection surface F4 of the liquid ejection head 10D according to Modification 3. The liquid ejection head 10D has a plurality of nozzle rows NL. The nozzle rows NL include a nozzle row NLA for ejecting the first ink and a nozzle row NLB for ejecting the second ink. When not distinguishing between nozzle rows NLA and NLB, they may be described as nozzle row NL.

[0085] The liquid ejection head 10D has a plurality of head chips 12D. A nozzle plate 11D having nozzles N formed thereon is provided on the head chip 12D. Nozzle rows NLA and NLB are respectively provided on the head chip 12D.

[0086] ​The plurality of nozzle rows NL extend along the V-axis direction. The nozzles N included in the nozzle row NL are arranged in the V-axis direction. The nozzle rows NLA and NLB are arranged at different positions from each other in the W-axis direction. When viewed in the W-axis direction, at least a part of the nozzle rows NLA and NLB overlap. When viewed in the Y-axis direction, at least a part of the nozzle row NLA and the nozzle row NLB overlap. When viewed in the X-axis direction, at least a part of the nozzle row NLA and the nozzle row NLB overlap.

[0087] When viewed in the X-axis direction, at least a part of the nozzle row NLA and the nozzle row NLB overlap, that is, when viewed in the gravity direction G1, at least a part of the nozzle row NLA and the nozzle row NLB overlap. The nozzle NA1 located at the upper end of the nozzle row NLA with respect to the gravity direction G1 is located above the nozzle NB1 located at the upper end of the nozzle row NLB with respect to the gravity direction G1.

[0088] Also, when comparing the nozzle NA of the nozzle row NLA and the nozzle NB of the nozzle row NLB that are located at the same position on the X-axis within the same print head 12D, the nozzle NA of the nozzle row NLA is located above the nozzle NB of the nozzle row NLB. Therefore, when considering the problem that ink overflows on the ejection surface F4 and color mixing occurs, similar to the above-described Modification 2, in the liquid ejection head 10D, the nozzle row NLA may be taken as an example of the first nozzle row, and the nozzle row NLB may be taken as an example of the second nozzle row.

[0089] In FIG. 16, virtual lines L5 and L6 are illustrated as two-dot chain lines. The virtual lines L5 and L6 are straight lines that are separated from each other in the Y-axis direction and extend along the X-axis direction. The virtual line L5 is located in the Y2 direction of the virtual line L6. When viewed in the Z-axis direction, the virtual line L5 overlaps the nozzle NA1, and the virtual line L6 overlaps the nozzle NB1. The nozzle row NLA includes a portion arranged in the Y2 direction with respect to the virtual line L6.

[0090] A liquid ejection apparatus 1 including such a liquid ejection head 10D exhibits the same operational effects as the liquid ejection apparatus 1 including the above-described liquid ejection head 10.

[0091] Next, with reference to FIG. 16, the arrangement of the nozzle rows NL of the liquid ejection heads 10G and 10H according to Modification 4 will be described. FIG. 16 is a bottom view showing the ejection surface of the liquid ejection heads 10G and 10H according to Modification 4. The liquid ejection apparatus 1 shown in FIG. 1 may include a head unit 20 having a plurality of liquid ejection heads 10G and 10H instead of the liquid ejection head 10. The head unit 20 has a plurality of liquid ejection heads 10G and 10H arranged alternately in the X-axis direction. In FIG. 16, a plurality of liquid ejection heads 10G and liquid ejection heads 10H arranged between the plurality of liquid ejection heads 10G are illustrated.

[0092] The liquid ejection head 10G includes, as a plurality of nozzle rows NL, a nozzle row NLA1 for ejecting the first ink, a nozzle row NLB1 for ejecting the second ink, a nozzle row NLC1 for ejecting the third ink, and a nozzle row NLD1 for ejecting the fourth ink.

[0093] The liquid ejection head 10G has a plurality of head chips 12G1, 12G2, 12G3, and 12G4. The nozzle row NLA1 is provided on the head chip 12G1, the nozzle row NLB1 is provided on the head chip 12G2, the nozzle row NLC1 is provided on the head chip 12G3, and the nozzle row NLD1 is provided on the head chip 12G4.

[0094] In the liquid ejection head 10G, the nozzle row NLA1 is an example of a first nozzle row, the nozzle row NLB1 is an example of a second nozzle row, the nozzle row NLC1 is an example of a third nozzle row, and the nozzle row NLD1 is an example of a fourth nozzle row. The plurality of nozzle rows NLA1, NLB1, NLC1, NLD1 extend in the X-axis direction. In the Y1 direction, the nozzle rows NLA1, NLC1, NLD1, NLB1 are arranged in this order. In the X-axis direction, the lengths are long in the order of the nozzle row NLB1, the nozzle row NLD1, the nozzle row NLC1, and the nozzle row NLA1. The nozzle row NLB1 is longer than the nozzle row NLA1 in the X-axis direction. In the inclined posture of the head unit 20, the nozzle rows NLA1, NLC1, NLD1, NLB1 are arranged at higher positions in this order.

[0095] The liquid ejection head 10H includes, as a plurality of nozzle rows NL, a nozzle row NLA2 that ejects a first ink, a nozzle row NLB2 that ejects a second ink, a nozzle row NLC2 that ejects a third ink, and a nozzle row NLD2 that ejects a fourth ink.

[0096] The liquid ejection head 10H has a plurality of head chips 12H1, 12H2, 12H3, 12H4. The nozzle row NLA2 is provided in the head chip 12H1, the nozzle row NLB2 is provided in the head chip 12H2, the nozzle row NLC2 is provided in the head chip 12H3, and the nozzle row NLD2 is provided in the head chip 12H4.

[0097] In the liquid ejection head 10H, the nozzle row NLA2 is an example of a first nozzle row, the nozzle row NLB2 is an example of a second nozzle row, the nozzle row NLC2 is an example of a third nozzle row, and the nozzle row NLD2 is an example of a fourth nozzle row. The plurality of nozzle rows NLA2, NLB2, NLC2, NLD2 extend in the X-axis direction. In the Y1 direction, the nozzle rows NLA2, NLC2, NLD2, and NLB2 are arranged in this order. In the X-axis direction, the lengths are long in the order of the nozzle row NLA2, the nozzle row NLC2, the nozzle row NLD2, and the nozzle row NLB2. The nozzle row NLA2 is longer than the nozzle row NLB2 in the X-axis direction. In the inclined posture of the head unit 20, the nozzle rows NLA2, NLC2, NLD2, and NLB2 are arranged at higher positions in this order.

[0098] A liquid ejection apparatus 1 including such liquid ejection heads 10G and 10H exhibits the same operational effects as the liquid ejection apparatus 1 including the above-described liquid ejection head 10.

[0099] Next, with reference to FIG. 17, a liquid ejection apparatus 1B according to the second embodiment will be described. FIG. 17 is a schematic diagram showing the liquid ejection apparatus 1B according to the second embodiment. The liquid ejection apparatus 1B includes a plurality of liquid ejection heads 30A to 30E, a drum 35 that conveys a medium PA, and pressure adjustment units 38A to 38E. In the description of the second embodiment, the same description as that of the first embodiment will be omitted. As described above, the X-axis direction, the Y-axis direction, and the Z-axis direction shown in each figure differ according to the postures of the liquid ejection heads 30A to 30E. Note that the drum 35 may be an intermediate transfer body on which the ink ejected from the liquid ejection heads 30A to 30E lands.

[0100] The drum 35 rotates around a rotation axis 35a extending in the X-axis direction. The medium PA is conveyed as the drum 35 rotates. The medium PA passes through positions corresponding to the liquid ejection heads 30A to 30E. Ink is ejected from the liquid ejection heads 30A to 30E onto the moving medium PA.

[0101] The plurality of liquid ejection heads 30A to 30E are arranged at mutually different positions in the circumferential direction of the drum 35. The ejection surfaces F31 to F35 of the liquid ejection heads 30A to 30E are arranged at different angles respectively. The ejection surfaces F31 to F35 are the surfaces of the nozzle plate.

[0102] FIG. 18 is a schematic view showing the posture of the liquid ejection head 30A. The liquid ejection head 30A has a nozzle row NLA for ejecting the first ink. A nozzle row NLA is formed on the ejection surface F31 of the liquid ejection head 30A. The plurality of nozzles NA included in the nozzle row NLA are arranged in the X-axis direction. The LA direction perpendicular to the ejection surface F31 is along the gravity direction G1. The ink ejected from the nozzles NA of the liquid ejection head 30A flies downward along the gravity direction G1.

[0103] FIG. 19 is a schematic view showing the posture of the liquid ejection head 30B. The liquid ejection head 30B has a nozzle row NLB for ejecting the second ink. A nozzle row NLB is formed on the ejection surface F32 of the liquid ejection head 30B. The plurality of nozzles NB included in the nozzle row NLB are arranged in the X-axis direction. The LB direction perpendicular to the ejection surface F32 is along the gravity direction G1. In FIG. 19, an upward direction G2 which is the direction opposite to the gravity direction G1 is shown. The ink ejected from the nozzles NB of the liquid ejection head 30B flies in the upward direction G2.

[0104] The liquid ejection head 30A is an example of a first liquid ejection head, and the liquid ejection head 30B is , an example of a second liquid ejection head. The ejection surface F31 is an example of a first ejection surface, and the ejection surface F32 is an example of a second ejection surface. The nozzle NA is an example of a first nozzle for ejecting the first ink, and the nozzle NB is an example of a second nozzle for ejecting the second ink. The viscosity of the first ink is High than the viscosity of the second ink.

[0105] In the liquid ejection head 30A shown in FIG. 18, the angle β1 formed by the ejection direction of the first ink ejected from the nozzle row NLA and the gravity direction G1 is 0 degrees. The angle β1 is an example of a first angle. Since the angle β1 is 0 degrees, it is not shown. In the liquid ejection head 30B shown in FIG. 19, the angle β2 formed by the ejection direction of the second ink ejected from the nozzle NB and the gravity direction G1 is 180 degrees. The angle β2 is an example of a second angle. The angle β2 is larger than the angle β1.

[0106] FIG. 20 is a schematic view showing the posture of the liquid ejection head 30C. The liquid ejection head 30C has a nozzle row NLC for ejecting a third ink. The nozzle row NLC is formed on the ejection surface F33 of the liquid ejection head 30C. A plurality of nozzles NC included in the nozzle row NLC are arranged in the X-axis direction. The LC direction perpendicular to the ejection surface F33 is along the K1 direction orthogonal to the gravity direction G1. The K1 direction orthogonal to the gravity direction G1 is shown in FIG. 20. The ink ejected from the nozzle NC of the liquid ejection head 30C flies along the K1 direction orthogonal to the gravity direction G1.

[0107] The liquid ejection head 30C is an example of a third liquid ejection head. The ejection surface F33 is an example of a third ejection surface. The nozzle NC is an example of a third nozzle for ejecting a third ink. The viscosity of the third ink is lower than the viscosity of the first ink and higher than the viscosity of the second ink.

[0108] The angle β3 formed by the K1 direction, which is the ejection direction of the third ink ejected from the nozzle NC, and the gravity direction G1 is 90 degrees. The angle β3 is an example of a third angle. The angle β3 is larger than the angle β1 and smaller than the angle β2.

[0109] FIG. 21 is a schematic view showing the posture of the liquid ejection head 30D. The liquid ejection head 30D has a nozzle row NLD for ejecting a fourth ink. The ejection surface F34 of the liquid ejection head 30D has the nozzle row NLD formed thereon. A plurality of nozzles ND included in the nozzle row NLD are , are arranged in the X-axis direction. The LD direction perpendicular to the ejection surface F34 is along the direction intersecting the gravity direction G1 and the K-axis direction. In FIG. 21, the gravity direction G1 and Orthogonal the intersecting direction K 1 are shown. The ink ejected from the nozzles ND of the liquid ejection head 30D flies obliquely upward along the direction intersecting the gravity direction G1 and the K-axis direction, that is, the Z1 direction in FIG. 21.

[0110] The liquid ejection head 30D is an example of a fourth liquid ejection head. The ejection surface F34 is an example of a fourth ejection surface. The nozzle ND is an example of a fourth nozzle that ejects a fourth ink. The viscosity of the fourth ink is lower than that of the third ink and higher than that of the second ink.

[0111] The ejection direction of the fourth ink ejected from the nozzle ND, that is, the angle β4 formed between the Z1 direction in FIG. 21 and the gravity direction G1, is 135 degrees. The angle β4 is an example of a fourth angle. The angle β4 is larger than the angle β3 and smaller than the angle β2.

[0112] FIG. 22 is a schematic diagram showing the posture of the liquid ejection head 30E. The liquid ejection head 30E has a nozzle row NLE that ejects a fifth ink. The ejection surface F35 of the liquid ejection head 30E is formed with the nozzle row NLE. A plurality of nozzles NE included in the nozzle row NLE are arranged in the X-axis direction. The LE direction perpendicular to the ejection surface F35 intersects the gravity direction G1 and the K-axis direction along Z1 direction . The ink ejected from the nozzles NE of the liquid ejection head 30E is in the direction intersecting the gravity direction G1 and the K-axis direction, that is, obliquely downward along the Z1 direction in FIG. 22 and flies.

[0113] The liquid ejection head 30E is an example of a fifth liquid ejection head. The ejection surface F35 is an example of a fifth ejection surface. The nozzle NE is an example of a fifth nozzle that ejects a fifth ink. The viscosity of the fifth ink is lower than the viscosity of the first ink and higher than the viscosity of the third ink.

[0114] The ejection direction of the fifth ink ejected from the nozzle NE, that is, the angle β5 formed by the Z1 direction in FIG. 22 and the gravitational direction G1, is 45 degrees. The angle β5 is an example of a fifth angle. The angle β5 is an angle larger than the angle β1 and smaller than the angle β3.

[0115] Next, referring to FIG. 17, the head differences H1 to H5 in the nozzle rows NLA to NLE will be described. The liquid ejection head 30A is provided with a pressure adjustment unit 38A. The liquid ejection head 30B is provided with a pressure adjustment unit 38B. The liquid ejection head 30C is provided with a pressure adjustment unit 38C. The liquid ejection head 30D is provided with a pressure adjustment unit 38D. The liquid ejection head 30E is provided with a pressure adjustment unit 38E. The pressure adjustment unit 38A is connected to the nozzle row NLA. The pressure adjustment unit 38B is connected to the nozzle row NLB. The pressure adjustment unit 38C is connected to the nozzle row NLC. The pressure adjustment unit 38D is connected to the nozzle row NLD. The pressure adjustment unit 38E is connected to the nozzle row NLE.

[0116] The pressure adjustment units 38A to 38E include, for example, a pressure adjustment valve, a sub-tank, or a pump, etc. including 。Pressure The pressure adjustment unit 38A adjusts the pressure of the first ink. The pressure adjustment unit 38B adjusts the pressure of the second ink. The pressure adjustment unit 38C adjusts the pressure of the third ink. The pressure adjustment unit 38D adjusts the pressure of the fourth ink. The pressure adjustment unit 38E adjusts the pressure of the fifth ink. The pressure adjustment units 38A to 38E can maintain the pressures of the first ink, the second ink, the third ink, the fourth ink, and the fifth ink at the same pressure. Note that each liquid ejection head 30A to 30E ink 8D adjusts the pressure of the fourth ink. The pressure adjustment unit 38E adjusts the pressure of the fifth ink. The pressure adjustment units 38A to 38E can maintain the pressures of the first ink, the second ink, the third ink, the fourth ink, and the fifth ink at the same pressure. and can maintain the pressures of the first ink, the second ink, the third ink, the fourth ink, and the fifth ink at the same pressure. Note that each of the liquid ejection heads 30A to 30E Assume that the resistance in the ink flow path is the same.

[0117] Figure 17 shows the height positions HA, HB , HC, HD, HE of the nozzle rows NLA, NLB, NLC, NLD, NLE. Height The positions HA, HE, HC, HD, HB are in descending order of height. The pressure adjusting unit 38A is located above the height position HA. The pressure adjusting unit 3 8B is located below the height position HB. The pressure adjusting unit 38C is at the same height as the height position HC. The pressure adjusting unit 38D is located below the height position HD. The pressure adjusting unit 38 E is located above the height position HE.

[0118] The head difference H1 between the pressure adjusting unit 38A and the nozzle row NLA is larger than the head difference H5 between the pressure adjusting unit 38E and the nozzle row NLE. The head difference H5 is larger than the head difference H3 between the pressure adjusting unit 38C and the nozzle row NLC. Note that the head difference H3 is not shown. The head difference H3 is larger than the head difference H4 between the pressure adjusting unit 38D and the nozzle row NLD. The head difference H4 is larger than the head difference H2 between the pressure adjusting unit 38B and the nozzle row NLB. That is, the head differences H1, H5, H3, H4, H2 are in descending order.

[0119] Also in the liquid ejecting apparatus 1B according to such a second embodiment, the same operational effects as those of the liquid ejecting apparatus 1 of the first embodiment are obtained.

[0120] In the liquid ejection device 1B, the positions of the nozzles NA, NB, NC, ND, and NE of the nozzle arrays NLA, NLB, NLC, NLD, and NLE are different according to the viscosity of the ink. The nozzle NA of the nozzle array NLA that ejects the first ink with the highest viscosity is arranged at a higher position in the gravitational direction G1 than the nozzles NB, NC, ND, and NE of the other nozzle arrays NLB, NLC, NLD, and NLE. The first ink is supplied to the nozzle NA of the nozzle array NLA having a larger head difference H1 compared to the nozzles NB, NC, ND, and NE of the nozzle arrays NLB, NLC, NLD, and NLE.

[0121] In the liquid ejection device 1B, the nozzle NB4 of the nozzle array NLB that ejects the second ink with the lowest viscosity is arranged at a lower position in the gravitational direction G1 than the nozzles NA, NC, ND, and NE of the other nozzle arrays NLA, NLC, NLD, and NLE. The second ink is supplied to the nozzle NB of the nozzle array NLB having a smaller head difference H2 compared to the nozzles NA, NC, ND, and NE of the nozzle arrays NLA, NLC, NLD, and NLE.

[0122] In the liquid ejection device 1B, since the nozzle NA of the nozzle array NLA that ejects the first ink with a higher viscosity is positioned above the nozzle NB of the nozzle array NLB that ejects the second ink with a lower viscosity in the gravitational direction G1, variations in the ink supply characteristics to the plurality of nozzle arrays NL that eject different types of ink can be reduced, and variations in the ink ejection characteristics in the plurality of nozzle arrays NL can be suppressed. As a result, the printing accuracy in the liquid ejection device 1B can be improved.

[0123] In the liquid ejection device 1B, the nozzle NC of the nozzle array NLC that ejects the third ink is positioned between the nozzle NA of the nozzle array NLA and the nozzle NB of the nozzle array NLB in the gravitational direction G1. The third ink having a lower viscosity than the first ink is supplied to the nozzle NC of the nozzle array NLC having a head difference H3 smaller than the head difference H1. The third ink having a higher viscosity than the second ink is supplied to the nozzle NC of the nozzle array NLC having a head difference H3 larger than the head difference H2.

[0124] In the liquid ejection device 1B, the nozzles ND of the nozzle row NLD that ejects the fourth ink are positioned between the nozzles NC of the nozzle row NLC and the nozzles NB of the nozzle row NLB with respect to the gravitational direction G1. The fourth ink having a lower viscosity than the third ink is supplied to the nozzles ND of the nozzle row NLD where the head difference H4 is smaller than the head difference H3. The fourth ink having a higher viscosity than the second ink is supplied to the nozzles ND of the nozzle row NLD where the head difference H4 is larger than the head difference H2.

[0125] In the liquid ejection device 1B, the nozzles NE of the nozzle row NLE that ejects the fifth ink are positioned between the nozzles NA of the nozzle row NLA and the nozzles NC of the nozzle row NLC with respect to the gravitational direction G1. The fifth ink having a lower viscosity than the first ink is supplied to the nozzles NE of the nozzle row NLE where the head difference H5 is smaller than the head difference H1. The fifth ink having a higher viscosity than the third ink is supplied to the nozzles NE of the nozzle row NLE where the head difference H5 is larger than the head difference H3.

[0126] In such a liquid ejection device 1B, since the height positions of the nozzles NA to NE are different according to the viscosity of the ink, variations in the ink supply characteristics to the plurality of nozzles NA to NE that eject different types of ink are reduced, and variations in the ink ejection characteristics at the plurality of nozzles NA to NE can be suppressed. As a result, the printing accuracy in the liquid ejection device 1B can be improved.

[0127] Note that the above-described embodiments merely show typical forms of the present invention, and the present invention is not limited to the above-described embodiments, and various modifications and additions are possible without departing from the gist of the present invention.

[0128] In the above-described embodiments, a plurality of inks having different colors are exemplified, but the present invention is not limited thereto. For example, the first ink and the second ink may have different viscosities and be the same color.

[0129] In the foregoing embodiments, the line-type liquid ejecting apparatus 1 including a line head has been exemplified. However, the present invention may also be applied to a serial-type liquid ejecting apparatus that reciprocates a carriage equipped with a liquid ejecting head 10 in the width direction of a medium PA.

[0130] The liquid ejecting apparatus 1 exemplified in the foregoing embodiments can be adopted not only in equipment dedicated for printing but also in various equipment such as facsimile machines and copying machines. However, the use of the liquid ejecting apparatus of the present invention is not limited to printing. For example, a liquid ejecting apparatus that discharges a solution of a coloring material is used as a manufacturing apparatus for forming a color filter of a display device such as a liquid crystal display panel. Also, a liquid ejecting apparatus that discharges a solution of a conductive material is used as a manufacturing apparatus for forming wirings and electrodes of a wiring board. Further, a liquid ejecting apparatus that discharges a solution of an organic substance related to a living body is used, for example, as a manufacturing apparatus for manufacturing a biochip.

Explanation of Reference Numerals

[0131] 1, 1B... liquid ejecting apparatus, 1a... housing, 10, 10B to 10D, 10G, 10H... liquid ejecting head, 11... nozzle plate, 30A... liquid ejecting head, 30B... liquid ejecting head, 30C to 30E... liquid ejecting head, 38A... pressure adjusting unit, 38B... pressure adjusting unit, F0... horizontal plane, F1... ejection surface, F31... ejection surface, F32... ejection surface, G1... direction of gravity, L1... first virtual line, N... nozzle, NL... nozzle row, NLA... nozzle row, NLB... nozzle row, NLC... nozzle row, NLD... nozzle row, Q1... first contact point, G2... second contact point, S1... rotation axis, X... X-axis direction, Y... Y-axis direction, Z... Z-axis direction.

Claims

1. A liquid ejection head having an ejection surface including a first nozzle row for ejecting a first ink, a second nozzle row for ejecting a second ink, and a third nozzle row for ejecting a third ink, and a medium conveyance mechanism, wherein the liquid ejection head can be held in a first posture in which the ejection surface is inclined with respect to a horizontal plane, and the medium conveyance mechanism conveys a medium upward from below with respect to the gravity direction at a position facing the ejection surface of the liquid ejection head held in the first posture, wherein the viscosity of the third ink is lower than the viscosity of the first ink and higher than the viscosity of the second ink, in the first posture, the first nozzle row is located above the second nozzle row with respect to the gravity direction, the third nozzle row is below the first nozzle row with respect to the gravity direction and above the second nozzle row, a liquid ejection device.

2. The liquid ejection device according to claim 1, wherein a difference between the viscosity of the first ink and the viscosity of the second ink is 0.5 mPa·S or more.

3. The liquid ejection device according to claim 1 or 2, wherein the first nozzle row and the second nozzle row are formed on a common nozzle plate.

4. When a direction in which an intersection line between the ejection surface in the first posture and the horizontal plane extends is defined as a first direction, and a direction orthogonal to the first direction in the ejection surface is defined as a second direction, the liquid ejection device according to claim 3, wherein at least a part of the first nozzle row and the second nozzle row overlap when viewed in the second direction.

5. The liquid ejection device according to any one of claims 1 to 4, wherein the first nozzle row and the second nozzle row are arranged with a space therebetween when viewed in the first direction, where the direction in which an intersection line between the ejection surface in the first posture and the horizontal plane extends is defined as the first direction.

6. The nozzles of the first nozzle row located at the same position on a virtual axis along the extending direction of the intersection line between the ejection surface in the first posture and the horizontal plane are located above the nozzles of the second nozzle row located at the same position on the virtual axis with respect to the gravity direction, the liquid ejection device according to any one of claims 1 to 5.

7. The ejection surface further includes a fourth nozzle row for ejecting a fourth ink, wherein the viscosity of the fourth ink is higher than the viscosity of the second ink and lower than the viscosity of the third ink, in the first posture, the fourth nozzle row is below the third nozzle row with respect to the gravity direction ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ and is the liquid according to any one of claims 1 to 6, which is located above the second nozzle row injector. **Claim 8** A first liquid injection head having a first injection surface including a first nozzle for injecting a first ink, A second liquid injection head having a second injection surface including a second nozzle for injecting a second ink, A first pressure adjustment unit that adjusts the pressure of the first ink supplied to the first nozzle, A second pressure adjustment unit that adjusts the pressure of the second ink supplied to the second nozzle, and 、 The viscosity of the first ink is higher than the viscosity of the second ink, The first liquid injection head is arranged such that the angle formed by the direction in which the first ink is injected from the first nozzle and the direction of gravity is a first angle degree, The second liquid injection head is arranged such that the angle formed by the direction in which the second ink is injected from the second nozzle and the direction of gravity is a second angle greater than the first angle, The relative position of the first pressure adjustment unit with respect to the first injection surface is the same as the relative position of the second pressure adjustment unit with respect to the second injection surface. A liquid injection device. **Claim 9** A third liquid injection head having a third injection surface including a third nozzle for injecting a third ink is provided The viscosity of the third ink is higher than the viscosity of the second ink and lower than the viscosity of the first ink, 、 The third liquid injection head is arranged such that the angle formed by the direction in which the third ink is injected from the third nozzle and the direction of gravity is a third angle greater than the first angle and smaller than the second angle. The liquid injection device according to claim 8. ​ ​ ​

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