Liquid ejecting apparatus and liquid ejecting head

Abstract

A liquid ejecting apparatus and a liquid ejecting head capable of improving printing accuracy are provided. The liquid ejecting apparatus according to the present application includes a liquid ejecting head (10) having an ejecting surface (F1) including a first nozzle row (NLA) ejecting a first ink and a second nozzle row (NLB) ejecting a second ink, and is capable of holding the liquid ejecting head (10) in a first posture in which the ejecting surface (F1) is inclined with respect to a horizontal surface (F0). The dynamic surface tension of the first ink is greater than the dynamic surface tension of the second ink. In the first posture, the first nozzle row (NLA) is located upward of the second nozzle row (NLB) with respect to a direction of gravity (G1).

Description

Technical Field

[0001] This invention relates to a liquid injection device and a liquid injection head. Background Technology

[0002] In record heads that spray multiple types of ink, there are cases where the ink spraying surface is tilted relative to the horizontal plane (for example, see Patent Document 1).

[0003] For each type of ink, there are cases where the dynamic surface tension of the ink varies. In existing technology, the combined effect of the varying dynamic surface tensions of multiple inks and the effect of the spray surface tilt has not been considered.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2014-34170 Summary of the Invention

[0005] One aspect of the present invention relates to a liquid jetting device comprising a liquid jetting head having a jetting surface including a first nozzle array for jetting a first ink and a second nozzle array for jetting a second ink. The liquid jetting device is capable of holding the liquid jetting head in a first orientation in which the jetting surface is tilted relative to a horizontal plane. The dynamic surface tension of the first ink is greater than that of the second ink. In the first orientation, the first nozzle array is positioned above the second nozzle array with respect to the direction of gravity.

[0006] One aspect of the present invention relates to a liquid jetting apparatus comprising: a first liquid jetting head having a first jetting surface including a first nozzle for jetting a first ink; and a second liquid jetting head having a second jetting surface including a second nozzle for jetting a second ink. The dynamic surface tension of the first ink is greater than the dynamic surface tension of the second ink. The first jetting surface is configured such that the angle between the jetting direction of the first ink jetted from the first nozzle and the direction of gravity is a first angle, and the second jetting surface is configured such that the angle between the jetting direction of the second ink jetted from the second nozzle and the direction of gravity is a second angle greater than the first angle.

[0007] One aspect of the present invention relates to a liquid jetting head comprising: a first nozzle array for jetting a first ink; a second nozzle array for jetting a second ink; and a third nozzle array for jetting a third ink. The dynamic surface tension of the third ink is less than that of the first ink and greater than that of the second ink. The third nozzle array is located between the first and second nozzle arrays with respect to the direction of gravity. Attached Figure Description

[0008] Figure 1 This is a schematic diagram illustrating the liquid injection device according to the first embodiment.

[0009] Figure 2 A block diagram representing the ink flow path.

[0010] Figure 3 A bottom view showing a nozzle plate with rows of nozzles.

[0011] Figure 4 A schematic diagram of a liquid jet head showing its tilted orientation relative to a horizontal plane, and a diagram showing the head difference in the nozzle array.

[0012] Figure 5 This is a cross-sectional view of the nozzle plate involved in Comparative Example 1, and a diagram showing the state in which ink droplets are overflowing from the nozzle.

[0013] Figure 6 This is a cross-sectional view of the nozzle plate involved in Comparative Example 1, and a diagram showing the state of ink droplets overflowing from the nozzle and hanging down along the spray surface.

[0014] Figure 7 This is a cross-sectional view of the nozzle plate involved in Example 1, and a diagram showing the state in which ink droplets are overflowing from the nozzle.

[0015] Figure 8 This is a schematic diagram showing the liquid injection head involved in Embodiment 2, and a diagram showing the inclined posture of the injection surface tilted upwards.

[0016] Figure 9 This is a schematic diagram showing the liquid injection head involved in Embodiment 3, and a diagram showing the injection surface being perpendicular to the horizontal plane.

[0017] Figure 10 This is a schematic diagram illustrating the liquid injection device involved in Example 4.

[0018] Figure 11 This is a schematic diagram illustrating the liquid injection device involved in Example 5.

[0019] Figure 12 This is a schematic diagram illustrating the liquid injection device involved in Example 6.

[0020] Figure 13 A table showing the composition of the inks involved in the embodiments.

[0021] Figure 14 A bottom view showing the spray surface of the liquid injection head involved in Modified Example 1.

[0022] Figure 15 This is a bottom view showing the spray surface of the liquid injection head involved in Modified Example 2.

[0023] Figure 16This is a bottom view showing the spray surface of the liquid injection head involved in Modified Example 3.

[0024] Figure 17 This is a bottom view showing the spray surface of the liquid injection head involved in Modified Example 4.

[0025] Figure 18 This is a schematic diagram illustrating the liquid injection device according to the second embodiment.

[0026] Figure 19 A schematic diagram showing the configuration of the liquid injection head.

[0027] Figure 20 A schematic diagram showing the configuration of the liquid injection head.

[0028] Figure 21 A schematic diagram showing the configuration of the liquid injection head.

[0029] Figure 22 A schematic diagram showing the configuration of the liquid injection head.

[0030] Figure 23 A schematic diagram showing the configuration of the liquid injection head. Detailed Implementation

[0031] Hereinafter, the methods for implementing the present invention will be described with reference to the accompanying drawings. However, the dimensions and scales of the various parts in the drawings may sometimes differ appropriately from the actual situation. Furthermore, although various technically preferred limitations have been imposed on the embodiments described below as preferred specific examples of the present invention, the scope of the present invention is not limited to these embodiments unless otherwise specifically limited in the following description.

[0032] In the following description, the three intersecting directions will sometimes be referred to as the X-axis, Y-axis, and Z-axis. The X-axis includes the X1 and X2 directions, which are opposite directions to each other. The X-axis is an example of the first direction. The Y-axis includes the Y1 and Y2 directions, which are opposite directions to each other. The Y-axis is an example of the second direction. The Z-axis includes the Z1 and Z2 directions, which are opposite directions to each other. The X-axis, Y-axis, and Z-axis are orthogonal. Furthermore, the Y-axis and Z-axis are directions referenced to the jet surface F1 described later.

[0033] Furthermore, let's define the downward direction of gravity as the gravity direction G1, and the direction orthogonal to both the gravity direction G1 and the X-axis direction as the K-axis direction. Let's define the direction opposite to the gravity direction G1 as the upward direction G2. The K-axis direction includes the K1 direction and the K2 direction, which are opposite to each other. The K-axis direction is an example of a third direction. The K-axis direction is an example of a horizontal direction. The horizontal direction is orthogonal to the gravity direction G1. The third direction is orthogonal to both the first direction and the gravity direction G1.

[0034] Figure 1 , represents a schematic diagram of the liquid injection device 1 according to the first embodiment. Figure 2 This is a block diagram illustrating the ink flow path. Liquid jetting device 1 is an inkjet printing apparatus that jets an example of a "liquid," namely ink, as ink droplets onto a medium PA. Liquid jetting device 1 is a so-called row-type printing apparatus in which multiple nozzles that jet ink are distributed across the entire width direction of the medium PA. The medium PA is typically printing paper. However, the medium PA is not limited to printing paper; for example, it can be any printing material such as resin film or fabric.

[0035] The liquid jetting device 1 includes a liquid jetting head 10 having a jetting surface F1 inclined relative to the horizontal plane F0. The liquid jetting device 1 includes: multiple liquid containers 2, a control unit 3, a media delivery mechanism 4, an ink supply unit 5, and the liquid jetting head 10. The liquid jetting device 1 may have one liquid jetting head 10 or multiple liquid jetting heads 10. The liquid jetting device 1 of this embodiment includes one liquid jetting head 10. When multiple liquid jetting heads 10 are included, the multiple liquid jetting heads 10 are arranged in the X-axis direction and form a row head.

[0036] The control unit 3 controls the operation of various components of the liquid injection device 1. The control unit 3 includes, for example, a processing circuit such as a CPU or FPGA, and a storage circuit such as a semiconductor memory. Various programs and data are stored in this storage circuit. The processing circuit executes the program and uses the data appropriately to achieve various controls. CPU is short for Central Processing Unit. FPGA is short for Field Programmable Gate Array.

[0037] The media conveying mechanism 4 is controlled by the control unit 3 and conveys the medium PA in the conveying direction DM. The conveying direction DM is the conveying direction of the medium PA at the position opposite to the spray surface F1, and is parallel or substantially parallel to the Y-axis direction. The media conveying mechanism 4 includes a conveying roller that is elongated along the width direction of the medium PA, and a motor that rotates the conveying roller. In addition, the media conveying mechanism 4 is not limited to a structure using a conveying roller; for example, it can also be a roller or a seamless belt that conveys the medium PA while it is being attracted to the outer peripheral surface by electrostatic force or the like.

[0038] In the liquid injection device 1, a media transport path 4a is formed for transporting the media PA. The media transport path 4a is a path from the paper supply section 4b to the paper discharge section 4c. The media transport mechanism 4 transports the media PA along the media transport path 4a. The paper supply section 4b and the paper discharge section 4c include trays capable of storing the media PA.

[0039] Liquid container 2 stores ink. Specific examples of liquid container 2 include, for instance, a box removably installed in the liquid dispensing device 1, a bag-shaped ink pouch formed of a flexible film, and an ink canister capable of replenishing ink. Furthermore, the type of ink stored in liquid container 2 is arbitrary.

[0040] Liquid container 2 includes liquid containers 2A, 2B, 2C, and 2D. Liquid container 2A contains a first ink. Liquid container 2B contains a second ink. Liquid container 2C contains a third ink. Liquid container 2D contains a fourth ink. For example, the first, second, third, and fourth inks are inks of different colors. The dynamic surface tensions of these first, second, third, and fourth inks are different. The dynamic surface tension of the first ink is greater than that of the second ink. The dynamic surface tension of the third ink is less than that of the first ink but greater than that of the second ink. The dynamic surface tension of the fourth ink is less than that of the third ink but greater than that of the second ink. The composition of each type of ink and the determination of its dynamic surface tension will be described later.

[0041] The difference in dynamic surface tension between the first ink and the second ink is greater than 1.0 mN / m. In the dynamic surface tension measurement described later, with a lifetime of 10 msec, the dynamic surface tension of the first ink is greater than that of the second ink. With a lifetime of 10 msec, the dynamic surface tension of the first ink is greater than that of the third ink, the third ink is greater than that of the fourth ink, and the fourth ink is greater than that of the second ink.

[0042] The ink supply unit 5 includes ink channels 6 and 7 for supplying ink from the liquid container 2 to the liquid nozzle 10, and a pressure regulating unit 8 for regulating the pressure of the ink within the liquid nozzle 10. The ink channel 6 includes a channel from the liquid container 2 to the pressure regulating unit 8. The ink channel 7 includes a channel from the pressure regulating unit 8 to the liquid nozzle 10. The ink channel 7 includes a channel formed within the liquid nozzle 10. The ink channels 6 and 7 may include, for example, channel components or pipes / hose formed with grooves, recesses, through holes, etc.

[0043] The pressure regulating unit 8 regulates the pressure of the ink supplied to the liquid injection head 10 by applying a predetermined pressure to the nozzle N. The pressure regulating unit 8 may be, for example, a negative pressure generating unit including a pressure regulating valve. This negative pressure generating unit may also be configured to have a pressure regulating valve and a flexible member, and control the opening and closing of the pressure regulating valve by moving the pressure regulating valve using the flexure of the flexible member, thereby applying a negative pressure within a predetermined range to the nozzle N. The pressure regulating valve opens and closes the ink flow channel, and the flexible member flexes based on the pressure difference between the downstream ink flow channel and atmospheric pressure compared to the pressure regulating valve.

[0044] Furthermore, the pressure regulating unit 8 can also regulate the pressure of the ink supplied to the liquid jet head 10 by using a temporary ink storage tank. Specifically, the pressure regulating unit 8 has a storage tank and an arbitrary sensor capable of detecting the amount of ink stored in the storage tank. If the amount of ink stored in the storage tank detected by the sensor decreases compared to a threshold, ink is replenished from the liquid container 2 to keep the amount of ink stored in the storage tank approximately constant. In other words, the pressure of the ink in the liquid jet head 10 can be regulated by maintaining the liquid level of the ink stored in the storage tank approximately constant, thereby adjusting the pressure of the ink in the liquid jet head 10 based on the head difference between the liquid level in the storage tank and the liquid jet head 10. Alternatively, the pressure of the ink supplied to the liquid jet head 10 can be regulated by using a compressor to set the pressure in the storage tank to a predetermined pressure.

[0045] The pressure regulating unit 8 includes pressure regulating units 8A, 8B, 8C, and 8D. Pressure regulating unit 8A is connected to liquid container 2A and regulates the pressure of the first ink. Pressure regulating unit 8B is connected to liquid container 2B and regulates the pressure of the second ink. Pressure regulating unit 8C is connected to liquid container 2C and regulates the pressure of the third ink. Pressure regulating unit 8D is connected to liquid container 2D and regulates the pressure of the fourth ink.

[0046] Figure 3 The image shows a bottom view of a nozzle plate 11 with multiple nozzle rows NL. The liquid ejection head 10 includes a nozzle plate 11 having multiple nozzle rows NL. The nozzle rows NL include multiple nozzles N for ejecting ink. The surface of the nozzle plate 11 facing the medium PA is the ink ejection surface F1. Multiple nozzles N are formed on the ink ejection surface F1. The ink ejection surface F1 is configured to be separate from the medium PA.

[0047] Multiple nozzle rows NL include nozzle rows NLA, NLB, NLC, and NLD. Nozzle row NLA includes multiple nozzles N that spray a first ink. Nozzle row NLB includes multiple nozzles N that spray a second ink. Nozzle row NLC includes multiple nozzles N that spray a third ink. Nozzle row NLD includes multiple nozzles N that spray a fourth ink. Additionally, without distinguishing between nozzle rows NLA, NLB, NLC, and NLD, there may be cases where it is described as nozzle row NL.

[0048] The nozzle array NL comprises multiple nozzles N arranged in the X-axis direction. Each nozzle N is a through-hole extending through the thickness of the nozzle plate 11. The thickness of the nozzle plate 11 is along the Z-axis. Nozzle arrays NLA, NLB, NLC, and NLD are positioned at different locations in the Y-axis direction.

[0049] Oriented towards the Y1 direction, the nozzle arrays are arranged in the order of NLA, NLC, NLD, and NLB. The nozzle arrays NLA, NLC, NLD, and NLB are separated along the Y-axis. The NLC nozzle array is positioned between the NLA and NLB nozzle arrays along the Y-axis. The NLD nozzle array is positioned between the NLC and NLB nozzle arrays along the Y-axis.

[0050] When viewed along the Y-axis, at least a portion of nozzle arrays NLA, NLC, NLD, and NLB are repeated. In this embodiment, all of nozzle arrays NLA, NLC, NLD, and NLB are repeated when viewed along the Y-axis.

[0051] like Figure 1As shown, the liquid jet head 10 is held in an inclined position relative to the housing 1a of the liquid jetting device 1, for example. Furthermore, "the liquid jet head 10 is held relative to the housing 1a of the liquid jetting device 1" includes both the case where the liquid jet head 10 is directly fixed and held relative to the housing 1a, and the case where the liquid jet head 10 is held indirectly relative to the housing 1a via a component different from the housing 1a. The liquid jetting device 1 can hold the liquid jet head 10 in an inclined position where the spray surface F1 is inclined relative to the horizontal plane F0.

[0052] Figure 4 This is a schematic diagram of a liquid jet head 10 showing its tilted attitude with the jet surface F1 inclined relative to the horizontal plane F0, and a diagram showing the head differences H1 to H4 in the nozzle array NL. Figure 4 As shown, the spray surface F1 of the liquid jet head 10 is tilted relative to the horizontal plane F0 at an angle θ1. The tilt angle θ1 is, for example, an acute angle less than 90 degrees. The tilt angle θ1 can also be an obtuse angle greater than 90 degrees. The tilt angle θ1 can also be 90 degrees. The tilting attitude of the liquid jet head 10 with the spray surface F1 tilted relative to the horizontal plane F0 at an angle θ1 is an example of a first attitude.

[0053] exist Figure 4 In the tilted orientation of the liquid jet head 10 shown, multiple nozzle rows NL are positioned at different heights relative to the gravitational direction G1. Nozzle row NLA is positioned at height position HA, and nozzle row NLB is positioned at height position HB. Height position HA is located above height position HB. That is, nozzle row NLA, which jets a first ink with a higher dynamic surface tension, is located above nozzle row NLB, which jets a second ink with a lower dynamic surface tension.

[0054] Nozzle array NLC is positioned at height position HC. Height position HC is lower than height position HA and higher than height position HB. In the tilted position of liquid jet head 10, nozzle array NLC is lower than nozzle array NLA and higher than nozzle array NLB. That is, nozzle array NLC, which jets the third ink (which has the second largest dynamic surface tension among the first, second, and third inks), is positioned between nozzle array NLA and nozzle array NLB about the direction of gravity G1.

[0055] Nozzle array NLD is positioned at height position HD. Height position HD is lower than height position HC and higher than height position HB. In the tilted posture of liquid jet head 10, nozzle array NLD is lower than nozzle array NLC and higher than nozzle array NLB. That is, nozzle array NLD, which jets the fourth ink (which has the second largest dynamic surface tension among the second, third, and fourth inks), is positioned between nozzle array NLC and nozzle array NLB about the direction of gravity G1.

[0056] like Figure 4 As shown, when viewed in the X-axis direction, nozzle arrays NLA, NLC, NLD, and NLB are arranged in a way that is spaced apart from each other.

[0057] When comparing multiple nozzle rows NL, the nozzle row NL that sprays ink with a higher dynamic surface tension is positioned above the nozzle row NL that sprays ink with a lower dynamic surface tension.

[0058] Next, refer to Figures 5 to 7 This section explains the situation where, due to an abnormality in the pressure regulating unit 8, or due to cyclic cleaning caused by the ink circulating in the flow channel within the liquid jet head 10 via a circulation mechanism (not shown), the meniscus of nozzle N becomes under positive pressure, causing ink droplets 101 and 102 to droop along the jetting surface F1. Here, nozzle plates 11 and 111 for jetting two types of ink with different dynamic surface tensions are illustrated and explained. Figure 5 as well as Figure 6 The figure shows the nozzle plate 111 involved in Comparative Example 1. Figure 7 The figure illustrates the nozzle plate 11 according to Example 1. In the nozzle plate 111 according to Comparative Example 1, the nozzle array NLB, which sprays a second ink with a lower dynamic surface tension, is positioned above the nozzle array NLA, which sprays a first ink with a higher dynamic surface tension. In the nozzle plate 11 according to Example 1, the situation is reversed compared to Comparative Example 1, where the nozzle array NLA, which sprays the first ink, is positioned above the nozzle array NLB, which sprays the second ink.

[0059] Figure 5 The image shown is a cross-sectional view indicating that ink droplets 101 and 102 are overflowing from nozzles NA and NB of the nozzle plate 111 involved in Comparative Example 1. Figure 5 In the state shown, ink droplets 102 overflow from the upper nozzle array NLB as the second ink, and ink droplets 101 overflow from the lower nozzle array NLA as the first ink.

[0060] Figure 6This is a cross-sectional view of the nozzle plate 111 involved in Comparative Example 1, and a diagram showing the state in which ink droplets 101 overflowing from nozzle NA hang down along the spray surface F1. Figure 6 In the shown state, ink droplet 102 moves along the jetting surface F1 in the Y1 direction. Ink droplet 101 overflowing from the lower nozzle array NLA exists on the front side of nozzle NA. The front side of nozzle NA is the outside of nozzle NA and is located in the Z1 direction of nozzle NA. Ink droplet 102, with lower dynamic surface tension, is more likely to droop downwards due to gravity compared to ink droplet 101, which has higher dynamic surface tension. Ink droplet 102 moves in the Y1 direction, thus approaching the lower ink droplet 101. Over time, ink droplet 102 moves in the Y1 direction and comes into contact with ink droplet 101, thereby mixing ink droplet 102 and ink droplet 101 together.

[0061] In this state, when the first ink is ejected from the nozzle array NLA, the first ink, mixed with the second ink, will fall onto the media PA. Therefore, it is possible to reduce the printing accuracy.

[0062] Figure 7 This is a cross-sectional view of the nozzle plate 11 according to Embodiment 1, showing the state in which ink droplets 101 and 102 are overflowing from nozzles NA and NB. Figure 7 In the shown state, ink droplet 102 moves along the jetting surface F1 in the Y1 direction. In this case, ink droplet 101 overflowing from the upper nozzle array NLA will remain as is on the front of nozzle NA. The upper ink droplet 101 will not approach the lower nozzle array NLB. Although ink droplet 102 overflowing from the lower nozzle array NLB will move downwards due to gravity, ink droplet 102 will not approach ink droplet 101. Ink droplet 101 and ink droplet 102 will not mix together. In this way, since the nozzle array NLA, which jets the first ink with a larger dynamic surface tension, is located higher than the nozzle array NLB with respect to the direction of gravity G1, the mixing of the first ink and the second ink can be suppressed in Example 1.

[0063] exist Figure 4 In the liquid jetting head 10 of the first embodiment shown, the nozzle rows NLA, NLB, NLC, and NLD are configured according to the dynamic surface tension of the ink. The nozzle row NLA, which jets the first ink with the highest dynamic surface tension, is positioned higher relative to the other nozzle rows NLB, NLC, and NLD in the direction of gravity G1. In this way, since the nozzle row NLA, which jets the first ink whose droplets are least likely to droop, is positioned higher, mixing of the first ink with the other second, third, and fourth inks can be prevented.

[0064] In the liquid ejector head 10, the nozzle row NLB, which ejects the second ink with the lowest dynamic surface tension, is positioned lower relative to the other nozzle rows NLA, NLC, and NLD in the direction of gravity G1. In this way, since the nozzle row NLB, which ejects the second ink from which droplets are most likely to droop, is positioned lower, mixing of the second ink with the first, third, and fourth inks can be prevented.

[0065] In the liquid jet head 10, since the nozzle array NLA, which jets the first ink with a higher dynamic surface tension among multiple types of inks, is positioned above the nozzle array NLB, which jets the second ink with a lower dynamic surface tension, relative to the direction of gravity G1, the mixing of inks is suppressed. As a result, the printing accuracy in the liquid jetting apparatus 1 can be improved. Compared to the structure of Comparative Example 1, where the nozzle array NLB, which jets the second ink with a lower dynamic surface tension, is positioned higher than the nozzle array NLA, which jets the first ink with a higher dynamic surface tension, the possibility of multiple inks mixing is lower in the liquid jet head 10.

[0066] Next, refer to Figure 4 The head differences H1 to H4 in the nozzle array NL are explained. Figure 4 The height position H0 of the pressure regulating unit 8 is shown with respect to the direction of gravity G1. Height position H0 is located above the height positions HA, HB, HC, and HD of the nozzle rows NLA, NLB, NLC, and NLD. As described above, HA, HC, HD, and HB are arranged from high to low. The height position H0 of the pressure regulating unit 8 is not limited to being above the height positions of the nozzle rows NLA, NLB, NLC, and NLD. The height position H0 of the pressure regulating unit 8 can also be below the height positions of the nozzle rows NLA, NLB, NLC, and NLD. Furthermore, the height position H0 of the pressure regulating unit 8 can also be the height position between the nozzle rows NLA and NLB. Additionally, the height positions of multiple pressure regulating units 8A, 8B, 8C, and 8D are all height positions H0.

[0067] The head difference H2 between the pressure regulating unit 8 and the nozzle array NLB is greater than the head difference H4 between the pressure regulating unit 8 and the nozzle array NLD. The head difference H4 between the pressure regulating unit 8 and the nozzle array NLD is greater than the head difference H3 between the pressure regulating unit 8 and the nozzle array NLC. The head difference H3 between the pressure regulating unit 8 and the nozzle array NLC is greater than the head difference H1 between the pressure regulating unit 8 and the nozzle array NLA.

[0068] exist Figure 4With the liquid injection head 10 tilted, the head differences H1, H2, H3, and H4 acting on the nozzle array NL vary depending on the height position. Compared to the case with a smaller head difference, the case with a larger head difference makes it easier to supply ink to the nozzle array NL. Comparing the nozzle arrays NLA and NLB, the nozzle array NLA, with its smaller head difference H1, is less likely to be supplied with ink compared to the nozzle array NLB, which has a larger head difference H2.

[0069] Furthermore, for example, when the dynamic surface tensions of various types of inks differ, the capillary force and meniscus pressure resistance acting on the inks in nozzle N differ. The capillary force acting on the first ink with a higher dynamic surface tension is greater than that acting on the second ink with a lower dynamic surface tension. The meniscus pressure resistance of the first ink with a higher dynamic surface tension is greater than that of the second ink with a lower dynamic surface tension. Moreover, the first ink with a higher dynamic surface tension is easier to supply to the nozzle array NL compared to the second ink with a lower dynamic surface tension.

[0070] In other words, since the difference in the dynamic surface tension of the ink affects the ease of ink supply to the nozzle array NL, by distributing inks with different dynamic surface tensions according to the height of the nozzle array NL, the deviation in the ease of ink supply to the nozzle array NL caused by the head difference is mitigated, thereby reducing the deviation in the ease of ink supply to the nozzle array NL. As a result, the deviation in jetting characteristics can be reduced. Jetting characteristics, for example, include the weight Iw and velocity Vm of the jetted droplets.

[0071] In existing liquid jetting devices, the combined effect of varying dynamic surface tension and the tilt of the jetting surface F1 of the liquid jetting head 10 is not considered. Without taking into account the differences in dynamic surface tension for each ink and the tilt of the jetting surface F1, problems arise such as increased differences in the jetting characteristics of the ink for each nozzle row NL.

[0072] For example, when the pressure regulating units 8 corresponding to each of the multiple nozzle rows NL have a common structure, and when the distances (head differences) in the direction of gravity between each nozzle row NL and the pressure regulating units 8 corresponding to each nozzle row NL are equal, the pressure (negative pressure) acting on each nozzle row NL is the same. However, when the liquid injection head 10 is tilted, the multiple nozzle rows NL are arranged at different positions with respect to gravity, resulting in deviations in the head differences, and further differences in the dynamic surface tension of each ink, thus potentially causing deviations in the pressure acting on each nozzle row NL.

[0073] Furthermore, when supplying the readily available first ink to the readily available nozzle array NLB and the difficult-to-supply second ink to the difficult-to-supply nozzle array NLA, a significant difference arises between the jetting characteristics of the nozzle array NLA and the nozzle array NLB. In addition, in this case, there is a possibility that a relatively large negative pressure acting on the meniscus of the nozzle array NLA may cause air bubbles to be drawn into the nozzle N, or that a relatively large positive pressure acting on the meniscus of the nozzle array NLB may cause ink to overflow from the nozzle N and damage the meniscus.

[0074] In the liquid ejection head 10 of this embodiment, the nozzle rows NLA, NLB, NLC, and NLD are configured according to the dynamic surface tension of the ink. The nozzle row NLA, which ejects the first ink with the highest dynamic surface tension, is positioned at a higher position relative to the gravity direction G1 compared to the other nozzle rows NLB, NLC, and NLD. The nozzle row NLA, which has a smaller head difference H1, is supplied with the first ink that is easier to supply.

[0075] In the liquid jet head 10, the nozzle row NLB, which ejects the second ink with the lowest dynamic surface tension, is positioned at a lower position relative to the gravity direction G1 compared to the other nozzle rows NLA, NLC, and NLD. The nozzle row NLB, which has a larger head difference H2, is supplied with the second ink that is difficult to supply.

[0076] In the liquid jet head 10, since the nozzle array for jetting the first ink with a higher dynamic surface tension is positioned above the nozzle array for jetting the second ink with a lower dynamic surface tension relative to the direction of gravity G1, deviations in the ease of ink supply can be reduced, thereby suppressing deviations in the jetting characteristics of the inks in the multiple nozzle arrays. As a result, the printing accuracy in the liquid jetting device 1 can be improved.

[0077] Furthermore, in the liquid jetting device 1, since the multiple pressure regulating units 8 are arranged at the same height position H0 about the direction of gravity G1, compared with the case where the height positions of the multiple pressure regulating units 8 are different, the liquid jetting device 1 can be miniaturized and its structure can be simplified. By making the height positions H0 of the multiple pressure regulating units 8 consistent, the ink flow path can be simplified.

[0078] Next, refer to Figure 8 The tilting posture of the liquid injection head 10 involved in Example 2 will be described. Figure 8 Here is a schematic diagram of the liquid injection head 10 according to Embodiment 2, and a diagram showing the inclined posture of the injection surface F1 tilted in a way that is tilted upwards. Figure 8 The liquid injection head 10 of Embodiment 2 shown is... Figure 4The difference in the liquid injection head 10 of the first embodiment shown is that the tilt angle θ2 of the injection surface F1 is different from the tilt angle θ1.

[0079] The tilt angle θ2 is an obtuse angle, greater than 90 degrees, relative to the horizontal plane F0. The tilt angle θ2 is centered on the rotation axis along the X-axis and is a left-hand rotation angle as illustrated in the diagram. Figure 8 In this embodiment, the spray surface F1 is tilted upwards. The liquid spray head 10 of this embodiment 2 can achieve the same effect as the liquid spray head 10 of the first embodiment described above, and can suppress deviations in the spray characteristics of ink in multiple nozzle rows.

[0080] Next, refer to Figure 9 The tilting posture of the liquid injection head 10 involved in Example 3 will be described. Figure 9 Here, is a schematic diagram of the liquid injection head 10 according to Embodiment 3, and is a diagram showing the orientation of the injection surface F1 being perpendicular to the horizontal plane F0. Figure 9 The liquid injection head 10 of Embodiment 3 shown is... Figure 4 The difference in the liquid jet head 10 of the first embodiment shown is that the angle θ3 of the jetting surface F1 is different from the tilt angle θ1. Furthermore, the tilting posture of the liquid jet head 10 can also include a posture that is perpendicular to the horizontal plane F0. In this embodiment, the case where the jetting surface F1 is perpendicular to the horizontal plane F0 is sometimes referred to as tilting. The angle θ3 is 90 degrees relative to the horizontal plane F0, which is a right angle. The liquid jet head 10 according to this embodiment 3 can achieve the same effects as the liquid jet head 10 according to the first embodiment described above, and can reduce the deviation in the ease of ink supply, thereby suppressing the deviation in the ink jetting characteristics of the multiple nozzle rows.

[0081] Next, refer to Figure 10 The attitude change of the liquid injection head 10 involved in Example 4 will be explained. Figure 10 This is a schematic diagram illustrating the liquid injection head 10 according to Example 4. Figure 10 In the diagram, a liquid jet head 10 in a first posture P1, where the jet surface F1 is tilted relative to the horizontal plane F0, is illustrated with solid lines, while a liquid jet head 10 in a second posture P2, where the jet surface F1 is configured along the horizontal plane F0, is illustrated with dashed lines. The liquid jet head 10 is capable of rotational movement about a rotation axis S1 extending in the X-axis direction.

[0082] The attitude of the liquid injection head 10 can be changed to multiple attitudes, including a first attitude P1 and a second attitude P2. The liquid injection device 1 according to Embodiment 4 has an attitude changing mechanism 13 that changes the attitude of the liquid injection head 10. The attitude changing mechanism 13 includes a bearing 14 that holds a rotating shaft S1 extending in the X-axis direction, and a drive mechanism 15 that rotates the rotating shaft S1. The bearing 14 supports the rotating shaft S1 in a rotatable manner. The drive mechanism 15 includes, for example, a motor.

[0083] exist Figure 10 In the diagram, imaginary lines L1 and L2 are illustrated using double-dotted lines. Imaginary line L1 is an imaginary straight line passing through the center C1 between nozzle arrays NLA and NLB, and extending in a direction perpendicular to the injection surface F1 in the first posture P1. When viewed along the X-axis, imaginary line L1 extends along the Z-axis. When the liquid injection head 10 is in the first posture P1, the rotation axis S1 is located closer to nozzle array NLB when viewed from imaginary line L1. In other words, when the liquid injection head 10 is in the first posture P1, the rotation axis S1 is located closer to nozzle array NLB in the Y-axis direction compared to imaginary line L1. Imaginary line L1 is an example of a first imaginary line.

[0084] The imaginary line L2 is an imaginary straight line passing through the center C1 between nozzle arrays NLA and NLB, and extending in a direction perpendicular to the injection surface F1 in the second attitude P2. When viewed in the X-axis direction, imaginary line L2 extends in the Z-axis direction. Figure 10 In the diagram, dashed lines indicate the arrows representing the X-axis, Y-axis, and Z-axis directions in the second posture P2. The first posture P1 and the second posture P2 are offset by an angle θ1 when viewed along the X-axis. When the liquid injection head 10 is in the second posture P2, the rotation axis S1, when viewed from the imaginary line L2, is located near the nozzle array NLB. In other words, when the liquid injection head 10 is in the second posture P2, the rotation axis S1 is located in the Y-axis direction closer to the nozzle array NLB than along the imaginary line L2.

[0085] Furthermore, in both the first posture P1 and the second posture P2, the rotating shaft S1 can be located at the same position or at different positions. During the posture change of the liquid injection head 10 from the first posture P1 to the second posture P2, the liquid injection head 10 can also include linear movement. The liquid injection device 1 can cause the bearing 14 that holds the rotating shaft S1 to move linearly. For example, linear movement can be achieved via a rack and pinion. Other methods such as ball screws, guide grooves, actuators, and belt mechanisms can also be used to make the liquid injection head 10 move linearly.

[0086] Next, the centrifugal force acting on the meniscus during the rotational movement of the liquid jet head 10 will be explained. When the liquid jet head 10 rotates about the rotation axis S1, the centrifugal force acts on the meniscus within the multiple nozzle rows NL. The radius of rotation RA from the rotation axis S1 to the nozzle row NLA is greater than the radius of rotation RB from the rotation axis S1 to the nozzle row NLB. During the rotational movement of the liquid jet head 10, the magnitude of the centrifugal force acting on the meniscus of the nozzle row NLA differs from the magnitude of the centrifugal force acting on the meniscus of the nozzle row NLB. Specifically, the magnitude of the centrifugal force acting on the meniscus of the nozzle row NLA is greater than the magnitude of the centrifugal force acting on the meniscus of the nozzle row NLB.

[0087] The centrifugal force acting immediately after the initial rotation of the liquid jet head 10 causes the meniscus within the nozzle N to move outwards. In other words, this centrifugal force causes the meniscus to move in a direction away from the rotation axis S1. Furthermore, an inertial force acting on the meniscus within the nozzle N, which is moved outwards by this centrifugal force, is also acting. This inertial force is a force that moves the meniscus into the nozzle N. In other words, the inertial force acting on the meniscus in a direction closer to the rotation axis S1. Through this centrifugal force and the inertial force it generates, it is possible for the meniscus to either fly outwards from the nozzle N or for the meniscus to concave, introducing air bubbles into the nozzle N.

[0088] When the dynamic surface tension of the inks is the same, the meniscus of the nozzle array NLA, which has a higher centrifugal force, is more likely to collapse compared to the nozzle array NLB, which has a lower centrifugal force. In the liquid ejector head 10, a first ink with a higher dynamic surface tension is supplied to the nozzle array NLA, and a second ink with a lower dynamic surface tension is supplied to the nozzle array NLB. The first ink is supplied to the nozzle array NLA with the higher centrifugal force, and the second ink is supplied to the nozzle array NLB with the lower centrifugal force. Therefore, since the first ink with a higher dynamic surface tension is supplied to the nozzle with the higher centrifugal force, the collapse of the meniscus can be suppressed.

[0089] In the liquid jet head 10, inks with higher dynamic surface tension from various types of inks are supplied to the nozzle array NL with higher centrifugal force, while inks with lower dynamic surface tension are supplied to the nozzle array NL with lower centrifugal force. This suppresses the collapse of the meniscus of the ink within the nozzle N.

[0090] In the liquid jet head 10, by suppressing the collapse of the curved liquid surface, the entry of air bubbles into the nozzle N of the nozzle array NLA is suppressed, or the leakage of ink from the nozzle N of the nozzle array NLA is suppressed.

[0091] Furthermore, although the liquid injection head 10 according to Embodiment 4 has multiple nozzle rows NL extending in the X-axis direction, it may also include a nozzle row NL extending in a direction intersecting the X-axis when viewed from above towards the Z-axis direction on the injection surface F1. In this case, the radius of rotation from the rotation axis S1 to the nozzle row NL can be set as the distance between the nozzle N farthest from the rotation axis S1 among the multiple nozzles N constituting the nozzle row NL when viewed in the X-axis direction and the rotation axis S1.

[0092] Next, refer to Figure 11 The liquid injection head 10 involved in Example 5 will be described. Figure 11 This is a schematic diagram showing the liquid injection head 10 of the liquid injection device 1 according to Embodiment 5, and the cover 22 covering the injection surface F1 of the liquid injection head 10. The liquid injection device 1 is capable of performing maintenance operations. The liquid injection device 1 performs maintenance operations in the second posture P2 of the liquid injection head 10. The liquid injection device 1 in Figure 10 The printing action (recording action) is performed in the first posture P1 shown. Figure 11 The maintenance action is performed in the second posture P2 shown. That is, the first posture P1 is an example of a "recording posture," and the second posture P2 is an example of a "maintenance posture." Furthermore, the printing action is an example of a recording action. A "recording action" refers to the act of ejecting ink from nozzle N and allowing the ink to adhere to the medium, thereby recording text, images, etc.

[0093] The liquid jetting device 1 includes a cover 22, piping 23, and a pump 24, which are used during maintenance operations. The cover 22 covers the jetting surface F1 of the liquid jetting head 10. The cover 22 is configured to cover the openings of the nozzles N of the plurality of nozzle rows NL. A space 22a is formed in the cover 22 to receive the ink ejected from the nozzles N.

[0094] A pipe 23 is connected to the cover 22. The pipe 23 is for discharging ink present in the space 22a of the cover 22. A pump 24 is connected to the pipe 23. By driving the pump 24, the ink inside the cover 22 is drawn in and discharged outside the cover 22.

[0095] Maintenance operations for the liquid jetting device 1 include rinsing, suction cleaning, and pressurized cleaning. These maintenance operations are performed when the liquid jetting head 10 is in the second position P2. In the rinsing process, the pressure is varied by using the actuator of the liquid jetting head 10 to act on the pressure chamber connected to the nozzle N, thereby ejecting ink that does not contribute to recording from the nozzle N. In the suction cleaning process, for example, a pump 24 is used to draw ink from the nozzle N. Furthermore, in the pressurized cleaning process, the ink flow channel within the liquid jetting head 10 can be pressurized from an upstream position relative to the pressure chamber by using a pump (not shown), thereby discharging ink from the nozzle N.

[0096] In this way, in the liquid jetting device 1, unwanted ink in the nozzle N can be discharged to the outside of the liquid jetting head 10 through maintenance. In the second posture P2 of the liquid jetting head 10, the jetting surface F1 is parallel to the horizontal plane F0. In the liquid jetting device 1, since the maintenance operation can be performed in this second posture P2, the amount of ink remaining in the cover 22 can be reduced during air suction driven by the pump 24 while the space inside the cover 22 is open to the atmosphere. For example, since the cover 22 is tilted when the liquid jetting head 10 is in the first posture P1, ink may remain at the corner 22c inside the cover 22. On the other hand, in this embodiment, since the maintenance operation is performed with the bottom surface 22b of the cover 22 arranged along the horizontal plane F0, the amount of ink remaining in the cover 22 can be reduced. When the maintenance operation is performed in the tilted posture, there is a risk of ink leakage from the sealing part when the cover is closed. The sealing part when the cover is closed includes the part that contacts the cover 22 and the jetting surface F1.

[0097] In the liquid jetting device 1, the orientation of the liquid jetting head 10 can be changed from a first orientation P1 to a second orientation P2. As described above, when the liquid jetting head 10 rotates around the rotation axis S1, centrifugal force and the inertial force caused by this centrifugal force act on the meniscus of the ink in the nozzle array NL, which may cause the meniscus to collapse. In the liquid jetting device 1, since the first ink with the highest dynamic surface tension among various types of ink is supplied to the nozzle array NLA, which has the greatest centrifugal force and the inertial force caused by this centrifugal force, the possibility of meniscus collapse is reduced. By suppressing the collapse of the meniscus, the entry of air bubbles into the nozzle N of the jetting head 10 is suppressed, or the leakage of ink from the nozzle N of the nozzle array NLA is suppressed.

[0098] Next, refer to Figure 12The liquid injection device 1 according to Embodiment 6 will be described. In Embodiment 6, the effects of centrifugal force acting on the nozzle array NL of the liquid injection head 10 when the liquid injection device 1 is placed on the floor surface 26 will be described. The liquid injection head 10 of the liquid injection device 1 is arranged at an angle relative to the horizontal plane F0. The liquid injection device 1 includes a housing 1a for storing the liquid injection head 10. The liquid injection head 10 is held relative to the housing 1a. Feet 1c and 1d are provided on the bottom of the housing 1a. Feet 1c and 1d are disposed on the floor surface 26. The floor surface 26 is, for example, along the horizontal plane F0.

[0099] exist Figure 12 The diagram, marked with an arrow, illustrates the K-axis direction, which is orthogonal to the gravitational direction G1 when viewed along the X-axis. The K-axis direction follows... Figure 12 The feet 1c and 1d separate along the K-axis. For example, when observing the liquid jetting device 1 in the direction of gravity G1, the K-axis is along the long side of the housing 1a. Alternatively, the feet 1c and 1d may also separate in other directions.

[0100] Foot 1c includes contact Q1, and foot 1d includes contact Q2. Contact Q1 is an example of a first contact, and contact Q2 is an example of a second contact. Contacts Q1 and Q2 are the portions that contact the floor surface 26 when the basket 1a is placed on the floor surface 26. Contact Q1 is located in the K-axis direction near one end 1e of the basket 1a. Contact Q2 is located in the K-axis direction near the other end 1f of the basket 1a. One end 1e of the basket 1a is the end of the basket 1a in the K1 direction. The other end 1f of the basket 1a is the end in the K2 direction.

[0101] The center of gravity G of the liquid injection device 1 is located between contact Q1 and contact Q2 along the K-axis, and is closer to point Q1 than contact Q2. When viewed along the X-axis, the distance UR between contact Q1 and nozzle array NLA is greater than the distance DR between contact Q1 and nozzle array NLB. Similarly, when viewed along the X-axis, the distance UL between contact Q2 and nozzle array NLA is greater than the distance DL between contact Q2 and nozzle array NLB. The position of nozzle array NL is, for example, the center of the opening of nozzle N in the injection surface F1.

[0102] exist Figure 12 In the first posture P1 of the liquid jet head 10 shown, the distance UR is greater than the distance DL. In the first posture of the liquid jet head 10, the distance UL is longer than the distance DR.

[0103] For example, consider a scenario where multiple workers hold and move the liquid jetting device 1, eventually placing it on the floor surface 26. For instance, two workers separated along the K-axis can hold the liquid jetting device 1 from either side. When placing the liquid jetting device 1 on the floor surface 26, one worker near one end 1e contacts the floor surface 26 with their foot 1c first, followed by another worker near the other end 1f contacting the floor surface 26 with their foot 1d. With foot 1c contacting the floor surface 26 first, the liquid jetting device 1 rotates counterclockwise by R1 when viewed along the X-axis, using contact point Q1 as a fulcrum. In this case, since the distance UR is longer than the distance DR, a centrifugal force greater than that of the nozzle array NLA will act on the nozzle array NLB.

[0104] In this manner, when the liquid jetting device 1 is placed on the floor surface 26, different magnitudes of centrifugal force and inertial force caused by the centrifugal force are generated in the nozzle rows NLA and NLB according to the distances UR and DR from the contact point Q1. In the liquid jetting device 1, a first ink is supplied in the nozzle row NLA and a second ink is supplied in the nozzle row NLB. The first ink with a higher dynamic surface tension is supplied in the nozzle row NLA where the centrifugal force and inertial force are greater, while the second ink with a lower dynamic surface tension is supplied in the nozzle row NLB where the centrifugal force and inertial force are smaller. As a result, the possibility of meniscus collapse of the first ink in the nozzle row NLA can be reduced in the liquid jetting head 10. That is, the possibility of meniscus collapse is lower when the first ink is supplied in the nozzle row NLA compared to when the second ink is supplied in the nozzle row NLA.

[0105] In the case of liquid jetting device 1, since the center of gravity G of liquid jetting device 1 is located closer to foot 1c than foot 1d in the K-axis direction, the operator is more likely to have foot 1c contact the floor surface 26 first than foot 1d. In liquid jetting device 1, as described above, since the first ink is supplied in the nozzle array NLA, the possibility of the meniscus collapsing within the nozzle N of the nozzle array NLA is reduced.

[0106] Next, the case where the liquid jetting device 1 is configured such that foot 1d contacts the floor surface 26 before foot 1C will be described. When foot 1d contacts the floor surface 26 first, the liquid jetting device 1 rotates clockwise (R2) when viewed from the X-axis direction with contact point Q2 as the fulcrum. In this case, since the distance UL is longer than the distance DL, a centrifugal force and an inertial force caused by this centrifugal force act on the nozzle array NLA greater than those on the nozzle array NLB. Thus, when the liquid jetting device 1 is placed on the floor surface 26, different magnitudes of centrifugal force and inertial force are generated on the nozzle arrays NLA and NLB depending on the distances UL and DL from contact point Q2. In the liquid jetting head 10, a first ink with a higher dynamic surface tension is supplied to the nozzle array NLA, where the centrifugal force and the inertial force caused by this centrifugal force are greater, and a second ink with a lower dynamic surface tension is supplied to the nozzle array NLB, where the centrifugal force and the inertial force caused by this centrifugal force are smaller. Therefore, in the liquid ejector head 10, the possibility of meniscus collapse of the first ink within the nozzle array NLA can be reduced. In other words, the possibility of meniscus collapse is lower when the first ink is supplied to the nozzle array NLA compared to when the second ink is supplied to the nozzle array NLA.

[0107] For example, in the top view of the liquid jetting device 1 taken in the direction of gravity G1, the length along the K-axis is longer than the length along the X-axis. When moving such a liquid jetting device 1, it is easier to achieve balance when multiple workers are separated and holding the liquid jetting device 1 in the K-axis direction compared to when multiple workers are separated and holding the liquid jetting device 1 in the X-axis direction. In the liquid jetting head 10, the first ink is dispensed into the nozzle array NLA, thus suppressing the collapse of the meniscus compared to when the second ink is dispensed into the nozzle array NLA. In the liquid jetting device 1, either foot 1c or foot 1d can be lowered first.

[0108] Furthermore, when the liquid jetting device 1 is moved, multiple workers can separate and hold the liquid jetting device 1 in the X-axis direction. Since the nozzle array NLA is located above the nozzle array NLB with respect to the direction of gravity G1, the distance between the contact point of the housing 1a and the floor surface 26 located in the X1 direction and the nozzle array NLA is longer than the distance between that contact point and the nozzle array NLB. Similarly, the distance between the contact point of the housing 1a and the floor surface 26 located in the X2 direction and the nozzle array NLA is longer than the distance between that contact point and the nozzle array NLB. Therefore, regardless of whether the X1 direction end of the housing 1a is lowered first or the X2 direction end of the housing 1a is lowered first, the collapse of the meniscus can be suppressed because the first ink is dispensed into the nozzle array NLA.

[0109] Furthermore, although the liquid injection head 10 according to Embodiment 6 has multiple nozzle rows NL extending in the X-axis direction, it may also include a nozzle row NL extending in a direction intersecting the X-axis when viewed from above towards the injection surface F1 in the Z-axis direction. In this case, the distance from the contact point to the nozzle row NL can simply be set to the distance between the nozzle N farthest from the contact point among the multiple nozzles N constituting the nozzle row NL when viewed in the X-axis direction and the contact point.

[0110] Next, the method for measuring the dynamic surface tension of ink and the properties of ink will be explained. The dynamic surface tension of ink can be determined, for example, by the maximum bubble pressure method. Other methods can also be used to measure dynamic surface tension, such as the pendant drop method, the Wilhelmy method, and the ring method. In the maximum bubble pressure method, the tip of a thin tube is immersed in ink, and the maximum pressure required to release bubbles from the thin tube is measured. In this maximum bubble pressure method, bubbles are continuously generated at the tip of the thin tube to measure the maximum pressure.

[0111] In this maximum bubble pressure method, the time from the point when a new bubble is generated at the tip of the capillary tube during the measurement of maximum pressure until the maximum bubble pressure is reached is called the lifespan. The maximum bubble pressure is reached at the point when the radius of curvature of the bubble becomes equal to the radius of the capillary tube. The dynamic surface tension of ink is the surface tension of the ink in a state of motion. The dynamic surface tension of ink can be adjusted, for example, by changing the type and amount of surfactants, water-soluble organic solvents, resins, etc., contained in the ink.

[0112] Although the properties of the ink are described below, substances listed as "parts" and "%" in terms of component quantity are, unless otherwise specified, based on quality. Figure 13 A table showing the composition of the ink.

[0113] The pigment dispersion 1 is described below. A solution obtained by dissolving 5.0 g of concentrated hydrochloric acid in 5.5 g of water was cooled to 5°C, and 1.6 g of 4-aminophthalic acid was added to this solution. The container containing this solution was placed in an ice bath, stirred, and the temperature of the solution was maintained below 10°C. Simultaneously, a solution obtained by dissolving 1.8 g of sodium nitrite in 9.0 g of ion-exchanged water at 5°C was added. After stirring for 15 minutes, 6.0 g of pigment was added while stirring, and the mixture was stirred for another 15 minutes to obtain a slurry. The pigment added while stirring was carbon black with a specific surface area of ​​220 m² / g and a DBP oil absorption of 105 mL / 100 g. The obtained slurry was filtered through filter paper, the particles were thoroughly washed with water, and then dried in an oven at 110°C. Advantec filter paper, commercially available under the name "Standard Filter Paper No. 2," was used as the filter paper. After replacing sodium ions with potassium ions via ion exchange, an appropriate amount of ion-exchanged water is added to adjust the pigment content, thereby obtaining pigment dispersion 1 with a pigment content of 20.0%. Pigment dispersion 1 is used for the preparation of a first ink with a black hue.

[0114] The pigment dispersion 2 is described below. A styrene-ethyl acrylate-acrylic acid copolymer (resin dispersant) with an acid value of 150 mg KOH / g and a weight average molecular weight of 8,000 was prepared. The prepared resin dispersant was neutralized with an equimolar amount of potassium hydroxide with the same acid value and dissolved in deionized water to prepare an aqueous solution containing 20.0% resin (solid component). 20.0 parts of pigment (CI Pigment Blue 15:3), 30.0 parts of the aqueous solution of the resin dispersant, and 50.0 parts of deionized water were mixed to obtain a mixture.

[0115] The obtained mixture and 200 parts of 0.3 mm diameter zirconia beads were placed in an intermittent vertical sand mill (manufactured by IMEX). After dispersing with water for 5 hours, centrifugation was performed to remove coarse particles. After pressure filtration using a 3.0 μm microfilter (manufactured by Fujifilm), an appropriate amount of deionized water was added to obtain pigment dispersion 2. The obtained pigment dispersion 2 has a pigment content of 20.0% and a resin dispersant content of 6.0%. Pigment dispersion 2 is used in the preparation of a second ink with a blue-green hue.

[0116] Pigment dispersion 3 will be described. Except for changing the pigment to CI Pigment Yellow 74, the pigment dispersion 3 is obtained by following the same sequence as pigment dispersion 2 described above, resulting in a pigment dispersion 3 with a pigment content of 20.0% and a resin dispersant content of 6.0%. Pigment dispersion 3 is used in the preparation of a third ink having a yellow hue.

[0117] The pigment dispersion 4 is described below. Except for the substitution of 20.0 parts of pigment (CI pigment magenta 122), 20.0 parts of an aqueous solution of resin dispersant, and 60.0 parts of deionized water, the remaining components are prepared in the same order as pigment dispersion 2 described above, resulting in pigment dispersion 4 with a pigment content of 20.0% and a resin dispersant content of 4.0%. Pigment dispersion 4 is used in the preparation of a fourth ink having a magenta hue.

[0118] The preparation of the inks is explained. The components (unit: %) shown in Table 1 were mixed and thoroughly stirred, then pressure filtered through a 0.8 μm cellulose acetate filter (Advantec) to prepare the various inks. In Table 1, "Acetylenol E100" and "Acetylenol E60" are trade names of surfactants manufactured by Kawaken Fine Chemicals. At the bottom of Table 1, the dynamic surface tension γ with a lifetime of 10 ms is shown. The dynamic surface tension γ was measured at 25°C using a dynamic surface tension meter based on the maximum bubble pressure method. A dynamic surface tension meter manufactured by KRUSS, with the trade name "BUBBLE PRESSURE TENSIOMETER BP-2", was used as the dynamic surface tension meter.

[0119] Next, refer to Figure 14 The configuration of the nozzle array NL of the liquid injection head 10B involved in Modified Example 1 will be described. Figure 14 Here, we show a bottom view of the spray surface F2 of the liquid jet head 10B according to Modified Example 1. The liquid jet head 10B has multiple nozzle rows NL. The nozzle rows NL include: nozzle rows NLA1, NLA2, and NLA3 for spraying a first ink; nozzle rows NLB1, NLB2, and NLB3 for spraying a second ink; nozzle rows NLC1, NLC2, and NLC3 for spraying a third ink; and nozzle rows NLD1, NLD2, and NLD3 for spraying a fourth ink. Additionally, when not distinguishing between nozzle rows NLA1, NLA2, NLA3, NLB1, NLB2, NLB3, NLC1, NLC2, NLC3, NLD1, NLD2, and NLD3, they are sometimes referred to as nozzle row NL. In the liquid jet head 10B, nozzle row NLA is an example of a first nozzle row, nozzle row NLB is an example of a second nozzle row, nozzle row NLC is an example of a third nozzle row, and nozzle row NLD is an example of a fourth nozzle row.

[0120] The liquid ejection head 10B has multiple head chips 12. Each head chip 12 has a nozzle plate with nozzles N formed on it. Each head chip 12 has a nozzle array NL for ejecting one type of ink. Each head chip 12 has a pressure chamber (not shown) and an actuator. The actuator increases the pressure of the ink in the pressure chamber, thereby ejecting the ink from the nozzles N.

[0121] Nozzle arrays NLA1, NLA2, and NLA3 are positioned at different locations along the X-axis. Nozzle arrays NLA1 and NLA3 are also positioned at different locations along the Y-axis. Nozzle array NLA2 is located in the Y2 direction compared to nozzle arrays NLA1 and NLA3. In the first orientation P1 of the liquid injection head 10B, nozzle array NLA2 is positioned above nozzle arrays NLA1 and NLA3 relative to the direction of gravity G1. In the first orientation P1, the injection surface F2 is tilted relative to the horizontal plane.

[0122] The configuration of nozzle rows NLB1, NLB2, and NLB3 is the same as that of nozzle rows NLA1, NLA2, and NLA3. Nozzle rows NLB1, NLB2, and NLB3 are separated from nozzle rows NLA1, NLA2, and NLA3 in the Y-axis direction.

[0123] The configuration of nozzle groups NLC1, NLC2, and NLC3 is the same as that of nozzle groups NLA1, NLA2, and NLA3. In the Y-axis direction, nozzle groups NLC1, NLC2, and NLC3 are located between nozzle groups NLA1, NLA2, and NLA3 and nozzle groups NLB1, NLB2, and NLB3.

[0124] The configuration of nozzle groups NLD1, NLD2, and NLD3 is the same as that of nozzle groups NLA1, NLA2, and NLA3. In the Y-axis direction, nozzle groups NLD1, NLD2, and NLD3 are located between nozzle groups NLC1, NLC2, and NLC3 and nozzle groups NLB1, NLB2, and NLB3.

[0125] The liquid injection device 1 can also replace the liquid injection head 10 and have a liquid injection head 10B. The liquid injection device 1 with the liquid injection head 10B has the same function as the liquid injection device 1 with the liquid injection head 10 described above.

[0126] Next, refer to Figure 15 The configuration of the nozzle array NL of the liquid injection head 10C involved in Modified Example 2 will be described. Figure 15Here, is a bottom view of the spray surface F3 of the liquid injection head 10C involved in Modified Example 2. The liquid injection head 10C has multiple nozzle rows NL. The nozzle rows NL include a nozzle row NLA for spraying a first ink, a nozzle row NLB for spraying a second ink, a nozzle row NLC for spraying a third ink, and a nozzle row NLD for spraying a fourth ink. In addition, when the nozzle rows NLA, NLB, NLC, and NLD are not distinguished, they are sometimes referred to as nozzle row NL.

[0127] The liquid injection head 10C has multiple head chips 12C. Within each head chip 12C, a nozzle plate 11C is provided, on which nozzles N are formed. Within each head chip 12C, nozzle rows NLA, NLB, NLC, and NLD are respectively provided.

[0128] exist Figure 15 The diagram illustrates the mutually orthogonal V-axis and W-axis directions. The V-axis and W-axis directions are orthogonal to the Z-axis direction. The V-axis and W-axis directions are directions referenced to the injection surface F3. The V-axis direction includes directions V1 and V2. The W-axis direction includes directions W1 and W2. The V-axis direction intersects the X-axis direction at an angle α relative to the X-axis direction.

[0129] Multiple nozzle rows NL extend along the V-axis. The nozzles N contained within each nozzle row NL are arranged along the V-axis. Nozzle rows NLA and NLD are arranged along the V-axis. Nozzle rows NLA and NLD are separated along the V-axis. Nozzle rows NLA and NLD are separated along the Y-axis. Figure 15 In the diagram, imaginary lines L3 and L4 are shown as double-dotted lines. Imaginary lines L3 and L4 are straight lines that separate from each other in the Y-axis direction and run along the X-axis direction. Imaginary line L3 lies in the Y2 direction relative to imaginary line L4. Nozzle groups NLA and NLC are located in the Y2 direction relative to imaginary line L3, while nozzle groups NLB and NLD are located in the Y1 direction relative to imaginary line L4.

[0130] Nozzle arrays NLC and NLB are arranged in the V-axis direction. Nozzle arrays NLC and NLB are separated in the V-axis direction. Nozzle arrays NLC and NLB are separated in the Y-axis direction. In the liquid injection head 10C, nozzle arrays NLA and NLC are an example of a first nozzle array, and nozzle arrays NLD and NLB are an example of a second nozzle array.

[0131] When viewed in the Y-axis direction, the nozzle array NLA and nozzle arrays NLD and NLB at least partially overlap. For example, among two adjacent head chips 12C in the X-axis direction, the head chip configured in the X1 direction is designated as head chip 12C1, and the head chip configured in the X2 direction of head chip 12C1 is designated as head chip 12C2. The nozzle array NLA of head chip 12C1 and the nozzle arrays NLD and NLB of head chip 12C2 at least partially overlap when viewed in the Y-axis direction. In addition, the nozzle arrays NLA and NLD and NLB within the same head chip 12 may also at least partially overlap in the Y-axis direction.

[0132] Similarly, when viewed in the Y-axis direction, the nozzle array NLC and nozzle arrays NLD and NLB at least partially overlap. The nozzle array NLC of head chip 12C1 and the nozzle arrays NLD and NLB of head chip 12C2 at least partially overlap when viewed in the Y-axis direction. Furthermore, the nozzle arrays NLC and NLD and NLB within the same head chip 12 may also at least partially overlap in the Y-axis direction.

[0133] When viewed in the X-axis direction, nozzle arrays NLA and NLD, NLB are arranged with a gap in the Y-axis direction. When viewed in the X-axis direction, nozzle arrays NLC and NLD, NLB are arranged with a gap in the Y-axis direction.

[0134] Regarding the Y-axis direction, the spacing between the nozzle array NLA and the nozzle array NLC, which are set on the same head chip 12C, is narrower than the spacing between the nozzle array NLC set on the head chip 12C1 and the nozzle array NLA set on the head chip 12C2.

[0135] The nozzle NA1, located at the upper end of the nozzle array NLA with respect to gravity G1, is positioned above the nozzle ND1, located at the upper end of the nozzle array NLD with respect to gravity G1, and the nozzle NB1, located at the upper end of the nozzle array NLB.

[0136] The nozzle NC1, located at the upper end of the nozzle array NLC with respect to gravity G1, is positioned above the nozzle ND1, located at the upper end of the nozzle array NLD with respect to gravity G1, and the nozzle NB1, located at the upper end of the nozzle array NLB.

[0137] The liquid injection device 1 equipped with such a liquid injection head 10C can achieve the same effect as the liquid injection device 1 equipped with the liquid injection head 10 described above.

[0138] Furthermore, in a liquid injection head 10C having nozzle arrays NL that overlap at least partially with respect to the direction of gravity G1, considering the influence of head difference deviation as an issue as described above, it is desirable to determine the height relationship between the overlapping nozzle arrays NL by comparing the positions of the upper nozzles N of each nozzle array NL with respect to the direction of gravity G1. This is because the upper nozzles N in the nozzle array NL are the nozzles N most difficult to supply ink to due to the head difference; therefore, it is desirable to compare the heights of the upper nozzles N to ensure that the first ink can be supplied to these nozzles most difficult to supply ink to.

[0139] like Figure 15 As shown, the liquid injection head 10C includes nozzle rows NLA and NLC that overlap with each other at least partially with respect to the direction of gravity G1, and nozzle rows NLB and NLD that overlap with each other at least partially with respect to the direction of gravity G1. Furthermore, since nozzle NA1, located at the upper end of nozzle row NLA, is positioned above nozzle NC1, located at the upper end of nozzle row NLC, and nozzle ND1, located at the upper end of nozzle row NLD, is positioned above nozzle NB1, located at the upper end of nozzle row NLB, nozzle row NLA can be considered as an example of a first nozzle row, nozzle row NLB as an example of a second nozzle row, nozzle row NLC as an example of a third nozzle row, and nozzle row NLD as an example of a fourth nozzle row.

[0140] Furthermore, in a liquid jet head 10C having nozzle arrays NL that overlap at least partially with respect to the direction of gravity G1, considering the issue of multiple types of ink droplets overflowing from each nozzle array NL along the jetting surface F3 and mixing as described above, it is desirable to determine the height relationship between the nozzle arrays NL that overlap at least partially with each other by comparing them with each other in the extension direction of the intersection line between the jetting surface F3 and the horizontal plane F0 in the tilted posture of each nozzle array NL. This is because, since the intersection line between the jetting surface F3 and the horizontal plane F0 in the tilted posture is along the X-axis, the ink overflowing from the nozzle N will hang down in the Y1 direction on the jetting surface F3 due to gravity.

[0141] Furthermore, the problem of color mixing caused by ink dripping can easily occur within the same head chip 12C. In this modified example, within the same head chip 12C, nozzle arrays NLA and NLC overlap at least partially with respect to the direction of gravity G1, and nozzle arrays NLB and NLD overlap at least partially with respect to the direction of gravity G1.

[0142] Here, when comparing the nozzle NA of nozzle row NLA and the nozzle NC of nozzle row NLC within the same head chip 12C and located at the same position on the X-axis, since the nozzle NA of nozzle row NLA is located above the nozzle NC of nozzle row NLC, it is preferable to set nozzle row NLA as the nozzle row above nozzle row NLC. Similarly, when comparing the nozzle ND of nozzle row NLD and the nozzle NB of nozzle row NLB within the same head chip 12C and located at the same position on the X-axis, since the nozzle ND of nozzle row NLD is located above the nozzle NB of nozzle row NLB, it is preferable to set nozzle row NLD as the nozzle row above nozzle row NLB. In this way, it is also possible to set nozzle row NLA as the first nozzle row, nozzle row NLB as the second nozzle row, nozzle row NLC as the third nozzle row, and nozzle row NLD as the fourth nozzle row.

[0143] Next, refer to Figure 16 The configuration of the nozzle array NL of the liquid injection head 10D involved in Modified Example 3 will be described. Figure 16 Here, is a bottom view of the spray surface F4 of the liquid jet head 10D involved in Modified Example 3. The liquid jet head 10D has multiple nozzle rows NL. The nozzle rows NL include a nozzle row NLA for spraying a first ink and a nozzle row NLB for spraying a second ink. In addition, when nozzle rows NLA and NLB are not distinguished, they are sometimes referred to as nozzle row NL.

[0144] The liquid injection head 10D has multiple head chips 12D. On the head chip 12D, a nozzle plate 11D with nozzles N formed thereon is provided. On the head chip 12D, nozzle rows NLA and NLB are respectively provided.

[0145] Multiple nozzle rows NL extend along the V-axis. The nozzles N contained within each nozzle row NL are arranged along the V-axis. Nozzle rows NLA and NLB are positioned differently from each other along the W-axis. When viewed along the W-axis, at least a portion of nozzle rows NLA and NLB overlap. When viewed along the Y-axis, at least a portion of nozzle rows NLA and NLB overlap. When viewed along the X-axis, at least a portion of nozzle rows NLA and NLB overlap.

[0146] When viewed along the X-axis, nozzle arrays NLA and NLB at least partially overlap; that is, nozzle arrays NLA and NLB at least partially overlap with respect to the gravitational direction G1. Nozzle NA1, located at the upper end of nozzle array NLA with respect to the gravitational direction G1, is positioned above nozzle NB1, which is also located at the upper end of nozzle array NLB with respect to the gravitational direction G1.

[0147] Furthermore, when comparing the nozzle NA of nozzle row NLA and the nozzle NB of nozzle row NLB within the same head chip 12D and located at the same position on the X-axis, the nozzle NA of nozzle row NLA is positioned above the nozzle NB of nozzle row NLB. Therefore, regardless of whether the issue of the deviation between the pressure regulating unit 8 and the head difference of nozzle row NL is considered, or the issue of ink overflowing on the spray surface F4 and causing color mixing, it is sufficient to set nozzle row NLA as an example of the first nozzle row and nozzle row NLB as an example of the second nozzle row in the liquid spray head 10D, similar to the aforementioned modified example 2.

[0148] exist Figure 16 In the diagram, imaginary lines L5 and L6 are illustrated with double-dotted lines. Imaginary lines L5 and L6 are straight lines separated in the Y-axis direction and along the X-axis direction. Imaginary line L5 lies in the Y2 direction of imaginary line L6. When viewed in the Z-axis direction, imaginary line L5 overlaps with nozzle NA1, and imaginary line L6 overlaps with nozzle NB1. The nozzle array NLA includes the portion positioned in the Y2 direction compared to imaginary line L6.

[0149] The liquid injection device 1 equipped with such a liquid injection head 10D can achieve the same effect as the liquid injection device 1 equipped with the liquid injection head 10 described above.

[0150] Next, refer to Figure 17 The configuration of the nozzle array NL of the liquid injection heads 10G and 10H involved in Modified Example 4 will be described. Figure 17 Let be a bottom view of the injection surface of the liquid injection heads 10G and 10H involved in Modified Example 4. Figure 1 The liquid injection device 1 shown can also replace the liquid injection head 10 by having a head unit 20 with multiple liquid injection heads 10G and 10H. The head unit 20 has multiple liquid injection heads 10G and 10H arranged alternately in the X-axis direction. Figure 17 The figure shows a plurality of liquid injection heads 10G and a liquid injection head 10H disposed among the plurality of liquid injection heads 10G.

[0151] The liquid jet head 10G comprises multiple nozzle rows NL, including nozzle row NLA1 for jetting the first ink, nozzle row NLB1 for jetting the second ink, nozzle row NLC1 for jetting the third ink, and nozzle row NLD1 for jetting the fourth ink.

[0152] The liquid injection head 10G has multiple head chips 12G1, 12G2, 12G3, and 12G4. A nozzle array NLA1 is provided on head chip 12G1, a nozzle array NLB1 is provided on head chip 12G2, a nozzle array NLC1 is provided on head chip 12G3, and a nozzle array NLD1 is provided on head chip 12G4.

[0153] In the liquid injection head 10G, nozzle array NLA1 is an example of a first nozzle array, nozzle array NLB1 is an example of a second nozzle array, nozzle array NLC1 is an example of a third nozzle array, and nozzle array NLD1 is an example of a fourth nozzle array. Multiple nozzle arrays NLA1, NLB1, NLC1, and NLD1 extend in the X-axis direction. In the Y1 direction, nozzle arrays NLA1, NLC1, NLD1, and NLB1 are arranged sequentially. The lengths in the X-axis direction decrease in the order of nozzle arrays NLB1, NLD1, NLC1, and NLA1. Nozzle array NLB1 is longer than nozzle array NLA1 in the X-axis direction. In the tilted orientation of the head unit 20, nozzle arrays NLA1, NLC1, NLD1, and NLB1 are arranged in descending order of height.

[0154] The liquid jet head 10H comprises multiple nozzle rows NL, including nozzle row NLA2 for jetting the first ink, nozzle row NLB2 for jetting the second ink, nozzle row NLC2 for jetting the third ink, and nozzle row NLD2 for jetting the fourth ink.

[0155] The liquid injection head 10H has multiple head chips 12H1, 12H2, 12H3, and 12H4. A nozzle array NLA2 is provided on head chip 12H1, a nozzle array NLB2 is provided on head chip 12H2, a nozzle array NLC2 is provided on head chip 12H3, and a nozzle array NLD2 is provided on head chip 12H4.

[0156] In the liquid injection head 10H, nozzle array NLA2 is an example of a first nozzle array, nozzle array NLB2 is an example of a second nozzle array, nozzle array NLC2 is an example of a third nozzle array, and nozzle array NLD2 is an example of a fourth nozzle array. Multiple nozzle arrays NLA2, NLB2, NLC2, and NLD2 extend in the X-axis direction. In the Y1 direction, nozzle arrays NLA2, NLC2, NLD2, and NLB2 are arranged sequentially. The lengths in the X-axis direction decrease in the order of nozzle arrays NLA2, NLC2, NLD2, and NLB2. Nozzle array NLA2 is longer than nozzle array NLB2 in the X-axis direction. In the tilted orientation of the head unit 20, nozzle arrays NLA2, NLC2, NLD2, and NLB2 are arranged in descending order of height.

[0157] The liquid injection device 1 equipped with such liquid injection heads 10G and 10H can achieve the same effect as the liquid injection device 1 equipped with the liquid injection head 10 described above.

[0158] Next, refer to Figure 18 The liquid injection device 1B according to the second embodiment will be described. Figure 18 The diagram shows a schematic representation of the liquid jetting apparatus 1B according to the second embodiment. The liquid jetting apparatus 1B includes a plurality of liquid jetting heads 30A-30E, a roller 35 for conveying the medium PA, and pressure regulating units 38A-38E. Furthermore, in the description of the second embodiment, the same descriptions as in the first embodiment are omitted. As described above, the X-axis, Y-axis, and Z-axis directions shown in the figures vary depending on the orientation of the liquid jetting heads 30A-30E. Additionally, the roller 35 may be an intermediate transfer body from which ink ejected from the liquid jetting heads 30A-30E falls.

[0159] The roller 35 rotates about a rotation axis 35a extending in the X-axis direction. The medium PA is conveyed along with the rotation of the roller 35. 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 for the moving medium PA.

[0160] Multiple liquid injection heads 30A to 30E are arranged at different positions around the circumference of the roller 35. The injection surfaces F31 to F35 of the liquid injection heads 30A to 30E are arranged at different angles. The injection surfaces F31 to F35 are the surfaces of the nozzle plate.

[0161] Figure 19 This is a schematic diagram showing the orientation of the liquid ejector head 30A. The liquid ejector head 30A has a nozzle array NLA for ejecting the first ink. The nozzle array NLA is formed on the ejection surface F31 of the liquid ejector head 30A. The plurality of nozzles NA contained in the nozzle array NLA are arranged in the X-axis direction. The LA direction, perpendicular to the ejection surface F31, is along the gravitational direction G1. The ink ejected from the nozzles NA of the liquid ejector head 30A travels downwards along the gravitational direction G1.

[0162] Figure 20 This is a schematic diagram showing the orientation of the liquid ejector head 30B. The liquid ejector head 30B has a nozzle array NLB for ejecting a second ink. The nozzle array NLB is formed on the ejection surface F32 of the liquid ejector head 30B. The plurality of nozzles NB contained in the nozzle array NLB are arranged in the X-axis direction. The LB direction, perpendicular to the ejection surface F32, is along the gravitational direction G1. Figure 20The diagram shows the upward direction G2, which is opposite to the direction of gravity G1. The ink ejected from the nozzle NB of the liquid jet head 30B flies in the upward direction G2.

[0163] Liquid jet head 30A is an example of a first liquid jet head, and liquid jet head 30B is an example of a second liquid jet head. Jet surface F31 is an example of a first jet surface, and jet surface F32 is an example of a second jet surface. Nozzle NA is an example of a first nozzle for jetting the first ink, and nozzle NB is an example of a second nozzle for jetting the second ink. The dynamic surface tension of the first ink is greater than the dynamic surface tension of the second ink.

[0164] exist Figure 19 In the liquid jet head 30A shown, the angle β1 between the jetting direction of the first ink ejected from the nozzle NL and the direction of gravity G1 is 0 degrees. Angle β1 is an example of the first angle. Figure 20 In the liquid jet head 30B shown, the angle β2 between the jetting direction of the second ink ejected from the nozzle NL and the direction of gravity G1 is 180 degrees. Angle β2 is an example of a second angle. Angle β2 is an angle greater than angle β1.

[0165] Figure 21 This is a schematic diagram showing the orientation of the liquid ejector head 30C. The liquid ejector head 30C has a nozzle array NLC for ejecting a third ink. The nozzle array NLC is formed on the ejection surface F33 of the liquid ejector head 30C. The multiple nozzles NC contained in the nozzle array NLC are arranged in the X-axis direction. The LC direction, perpendicular to the ejection surface F33, is along the K1 direction, which is orthogonal to the gravitational direction G1. Figure 21 The diagram shows the K1 direction, which is orthogonal to the gravitational direction G1. The ink ejected from the nozzle NC of the liquid jet head 30C travels along the K1 direction, which is orthogonal to the gravitational direction G1.

[0166] Liquid jet head 30C is an example of a third liquid jet head. Jet surface F33 is an example of a third jet surface. Nozzle NC is an example of a third nozzle for jetting a third ink. The dynamic surface tension of the third ink is less than that of the first ink and greater than that of the second ink.

[0167] The angle β3 formed by the ejection direction of the third ink (K1) from nozzle NC and the direction of gravity G1 is 90 degrees. Angle β3 is an example of a third angle. Angle β3 is an angle greater than angle β1 and less than angle β2.

[0168] Figure 22This is a schematic diagram showing the orientation of the liquid ejector head 30D. The liquid ejector head 30D has a nozzle array NLD for ejecting a fourth ink. The nozzle array NLD is formed on the ejection surface F34 of the liquid ejector head 30D. The multiple nozzles ND included in the nozzle array NLD are arranged in the X-axis direction. The LD direction, perpendicular to the ejection surface F34, is along a direction intersecting the gravitational direction G1 and the K-axis direction. The ink ejected from the nozzles ND of the liquid ejector head 30D travels along a direction intersecting the gravitational direction G1 and the K-axis direction, that is... Figure 22 It flies diagonally upwards in the Z1 direction.

[0169] Liquid jet head 30D is an example of a fourth liquid jet head. Jet surface F34 is an example of a fourth jet surface. Nozzle ND is an example of a fourth nozzle for jetting a fourth ink. The dynamic surface tension of the fourth ink is less than that of the third ink and greater than that of the second ink.

[0170] The direction of the fourth ink ejected from nozzle ND, that is... Figure 22 The angle β4 between the Z1 direction and the gravitational direction G1 is 135 degrees. Angle β4 is an example of a fourth angle. Angle β4 is greater than angle β3 and less than angle β2.

[0171] Figure 23 This is a schematic diagram showing the orientation of the liquid ejector head 30E. The liquid ejector head 30E has a nozzle array NLE for ejecting a fifth ink. The nozzle array NLE is formed on the ejection surface F35 of the liquid ejector head 30E. The plurality of nozzles NE included in the nozzle array NLE are arranged in the X-axis direction. The LE direction, perpendicular to the ejection surface F35, is along a direction intersecting the gravitational direction G1 and the K-axis direction. The ink ejected from the nozzles NE of the liquid ejector head 30E travels along a direction intersecting the gravitational direction G1 and the K-axis direction, that is... Figure 23 It flies diagonally downwards in the Z1 direction.

[0172] Liquid jet head 30E is an example of a fifth liquid jet head. Jet surface F35 is an example of a fifth jet surface. Nozzle NE is an example of a fifth nozzle for jetting a fifth ink. The dynamic surface tension of the fifth ink is less than that of the first ink and greater than that of the third ink.

[0173] The direction of the fifth ink ejected from nozzle NE, that is... Figure 23 The angle β5 between the Z1 direction and the gravitational direction G1 is 45 degrees. Angle β5 is an example of the fifth angle. Angle β5 is an angle greater than angle β1 and less than angle β3.

[0174] Next, refer to Figure 18 The head differences H1 to H5 in nozzle arrays NLA to NLE are explained. Pressure regulating unit 38A is connected to nozzle array NLA via ink flow channel 37. Pressure regulating unit 38B is connected to nozzle array NLB via ink flow channel 37. Pressure regulating unit 38C is connected to nozzle array NLC via ink flow channel 37. Pressure regulating unit 38D is connected to nozzle array NLD via ink flow channel 37. Pressure regulating unit 38E is connected to nozzle array NLE via ink flow channel 37.

[0175] Pressure regulating units 38A to 38E can use the same structure as pressure regulating unit 8 described in the first embodiment. Furthermore, like in the first embodiment, pressure regulating units 38A to 38E have a common structure. Pressure regulating unit 38A regulates the pressure of the first ink. Pressure regulating unit 38B regulates the pressure of the second ink. Pressure regulating unit 38C regulates the pressure of the third ink. Pressure regulating unit 38D regulates the pressure of the fourth ink. Pressure regulating unit 38E regulates the pressure of the fifth ink.

[0176] exist Figure 18 The diagram shows the height position H0 of the pressure adjustment units 38A to 38E with respect to the direction of gravity G1. Height position H0 is located above the height positions HA, HB, HC, HD, and HE of the nozzle arrays NLA, NLB, NLC, NLD, and NLE. Positions HA, HE, HC, HD, and HB are arranged in descending order of height.

[0177] The head difference H2 between pressure regulator 38B and nozzle array NLB is greater than the head difference H4 between pressure regulator 38D and nozzle array NLD. The head difference H4 is greater than the head difference H3 between pressure regulator 38C and nozzle array NLC. The head difference H3 is greater than the head difference H5 between pressure regulator 38E and nozzle array NLE. The head difference H5 is greater than the head difference H1 between pressure regulator 38A and nozzle array NLA. That is, the head differences H2, H4, H3, H5, and H1 are arranged in descending order.

[0178] Even in the liquid injection device 1B according to this second embodiment, the same effect as the liquid injection device 1 of the first embodiment can be achieved.

[0179] In the liquid jetting device 1B, the positions of nozzles NA, NB, NC, ND, and NE in nozzle rows NLA, NLB, NLC, NLD, and NLE vary depending on the dynamic surface tension of the ink. The nozzle NA of nozzle row NLA, which jets the first ink with the highest dynamic surface tension, is positioned higher relative to the nozzles NB, NC, ND, and NE of the other nozzle rows NLB, NLC, NLD, and NLE, relative to the nozzles NB, NC, ND, and NE. In other words, the first ink is supplied to nozzle NA of nozzle row NLA, which is less likely to be supplied due to a smaller head difference H1 and is therefore more readily available.

[0180] In the liquid jetting device 1B, the nozzle NB of the nozzle row NLB, which jets the second ink with the lowest dynamic surface tension, is positioned at a lower position relative to the gravity direction G1 compared to the nozzles NA, NC, ND, and NE of the other nozzle rows NLA, NLC, NLD, and NLE. The nozzle NB of the nozzle row NLB, which has a larger head difference H2 and is easier to supply, is supplied with the second ink that is difficult to jet.

[0181] In the liquid jetting apparatus 1B, since the nozzle NA of the nozzle row NLA, which jets the first ink with a higher dynamic surface tension, is positioned above the nozzle NB of the nozzle row NLB, which jets the second ink with a lower dynamic surface tension, relative to the direction of gravity G1, the deviation in the supply characteristics of ink to the multiple nozzle rows NL that jet different types of ink can be reduced, thereby suppressing the deviation in the jetting characteristics of the ink in the multiple nozzle rows NL. As a result, the printing accuracy in the liquid jetting apparatus 1B can be improved.

[0182] In the liquid jetting device 1B, the nozzle NC of the nozzle array NLC that jets the third ink is located between the nozzle NA of the nozzle array NLA and the nozzle NB of the nozzle array NLB, about the direction of gravity G1. The nozzle NC of the nozzle array NLC, which has a smaller head difference H3 compared to H1, is supplied with a third ink having a smaller dynamic surface tension than the first ink. The nozzle NC of the nozzle array NLC, which has a smaller head difference H3 compared to H2, is supplied with a third ink having a larger dynamic surface tension than the second ink.

[0183] In the liquid jetting device 1B, the nozzle ND of the nozzle array NLD, which jets the fourth ink, is located between the nozzle NC of the nozzle array NLC and the nozzle NB of the nozzle array NLB, with respect to the direction of gravity G1. The nozzle ND of the nozzle array NLD, which has a smaller head difference H4 compared to the head difference H3, is supplied with the fourth ink, which has a smaller dynamic surface tension than the third ink. The nozzle ND of the nozzle array NLD, which has a smaller head difference H4 compared to the head difference H2, is supplied with the fourth ink, which has a larger dynamic surface tension than the second ink.

[0184] In the liquid jetting device 1B, the nozzle NE of the nozzle array NLE, which jets the fifth ink, is located between the nozzle NA of the nozzle array NLA and the nozzle NC of the nozzle array NLC, about the direction of gravity G1. The nozzle NE of the nozzle array NLE, which has a larger head difference H5 compared to the head difference H1, is supplied with a fifth ink having a smaller dynamic surface tension than the first ink. The nozzle NE of the nozzle array NLE, which has a smaller head difference H5 compared to the head difference H3, is supplied with a fifth ink having a larger dynamic surface tension than the third ink.

[0185] In this liquid jetting apparatus 1B, since the height positions of the nozzles NA to NE vary depending on the dynamic surface tension of the ink, the deviation in the supply characteristics of the ink supplied to the multiple nozzles NA to NE that jettison different types of ink can be reduced, thereby suppressing the deviation in the jetting characteristics of the ink in the multiple nozzles NA to NE. As a result, the printing accuracy in the liquid jetting apparatus 1B can be improved.

[0186] Furthermore, although in this embodiment the height position H0 of the pressure regulating units 38A to 38E is positioned above the height positions HA, HB, HC, HD, and HE of the nozzles NA, NB, NC, ND, and NE relative to the direction of gravity G1, it is not limited to this. The height position H0 may be located between positions HA and HB relative to the direction of gravity G1, or it may be located below positions HA, HE, HC, HD, and HB.

[0187] Furthermore, the foregoing embodiments are merely representative examples of the present invention, and the present invention is not limited to the foregoing embodiments. Various modifications and additions can be made without departing from the spirit of the present invention.

[0188] While the foregoing embodiments have illustrated various inks of different colors, the embodiments are not limited thereto. For example, the first ink and the second ink may also be inks of the same color but with different dynamic surface tensions.

[0189] Although the foregoing embodiments illustrate a linear liquid jetting device 1 with a linear head, the present invention can also be applied to a serial liquid jetting device in which a carriage equipped with a liquid jetting head 10 reciprocates in the width direction of the medium PA.

[0190] The liquid jetting apparatus 1 illustrated in the foregoing embodiments can be used not only in equipment specifically designed for printing, but also in various other devices such as fax machines or copiers. Clearly, the application of the liquid jetting apparatus of the present invention is not limited to printing. For example, a liquid jetting apparatus that jets a solution of color material can be used as a manufacturing apparatus for color filters in display devices such as liquid crystal display panels. Furthermore, a liquid jetting apparatus that jets a solution of conductive material can be used as a manufacturing apparatus for wiring or electrodes in wiring substrates. Additionally, a liquid jetting apparatus that jets a solution of organic matter related to living organisms can be used, for example, as a manufacturing apparatus for biochips.

[0191] Symbol Explanation

[0192] 1, 1B…Liquid injection device; 1a…Housing; 8A…Pressure regulating unit; 8B…Pressure regulating unit; 10, 10B~10D, 10G, 10H…Liquid injection head; 11…Nozzle plate; 30A…Liquid injection head; 30B…Liquid injection head; 30C~30E…Liquid injection head; 38A…Pressure regulating unit; 38B…Pressure regulating unit; F0…Horizontal plane; F1…Injection surface; F31…Injection surface; F32…Injection surface (second injection surface); G1…Gravity direction; L1…First imaginary line; N…Nozzle; NA…Nozzle; NB…Nozzle; NL…Nozzle array; NLA…Nozzle array; NLB…Nozzle array; NLC…Nozzle array; NLD…Nozzle array; Q1…First contact; Q2…Second contact; S1…Rotation axis; X…X-axis direction; Y…Y-axis direction; Z…Z-axis direction.

Claims

1. A liquid injection device, comprising: A liquid jetting head having a jetting surface comprising a first nozzle array for jetting a first ink and a second nozzle array for jetting a second ink; A first pressure regulating unit adjusts the pressure of the first ink supplied to the first nozzle array; The second pressure regulating unit adjusts the pressure of the second ink supplied to the second nozzle array. The first pressure regulating unit and the second pressure regulating unit are positioned at the same location with respect to the direction of gravity. The liquid injection device is capable of holding the liquid injection head in a first orientation in which the injection surface is tilted relative to the horizontal plane. The dynamic surface tension of the first ink is greater than that of the second ink. In the first posture, the first nozzle array is positioned above the second nozzle array relative to the direction of gravity.

2. The liquid injection device as claimed in claim 1, wherein, The difference between the dynamic surface tension of the first ink and the dynamic surface tension of the second ink is greater than 1.0 mN / m.

3. The liquid injection device as described in claim 1 or 2, wherein, The dynamic surface tension of the first ink with a lifespan of 10 msec is greater than that of the second ink with a lifespan of 10 msec.

4. The liquid injection device as claimed in claim 1, wherein, The first nozzle array and the second nozzle array are formed on a common nozzle plate.

5. The liquid injection device as claimed in claim 4, wherein, When the direction extending from the intersection of the spray surface and the horizontal plane in the first posture is defined as the first direction, and the direction within the spray surface that is orthogonal to the first direction is defined as the second direction,... When viewed in the second direction, the first nozzle array and the second nozzle array overlap by at least a portion.

6. The liquid injection device as claimed in claim 1, wherein, When the direction of the intersection of the spray surface and the horizontal plane in the first posture is defined as the first direction, When viewed in the first direction, the first nozzle array and the second nozzle array are arranged at a distance.

7. The liquid injection device as claimed in claim 1, wherein, The nozzle located at the upper end of the first nozzle column relative to the direction of gravity is positioned above the nozzle located at the upper end of the second nozzle column relative to the direction of gravity.

8. The liquid injection device as claimed in claim 1, wherein, The spraying surface also includes a third row of nozzles that spray a third ink. The dynamic surface tension of the third ink is less than that of the first ink and greater than that of the second ink. In the first posture, the third nozzle array is located below the first nozzle array and above the second nozzle array with respect to the direction of gravity.

9. The liquid injection device as claimed in claim 8, wherein, The spraying surface also includes a fourth row of nozzles that spray a fourth ink. The dynamic surface tension of the fourth ink is greater than that of the second ink and less than that of the third ink. In the first posture, the fourth nozzle array is located below the third nozzle array and above the second nozzle array with respect to the direction of gravity.

10. A liquid jetting apparatus comprising a liquid jetting head having a jetting surface including a first row of nozzles for jetting a first ink and a second row of nozzles for jetting a second ink. The liquid injection device is capable of holding the liquid injection head in a first orientation in which the injection surface is tilted relative to the horizontal plane. The dynamic surface tension of the first ink is greater than that of the second ink. In the first posture, the first nozzle array is positioned above the second nozzle array relative to the direction of gravity. The attitude of the liquid injection head can be changed to multiple attitudes, including the first attitude and a second attitude different from the first attitude. The liquid injection head is capable of rotating about a rotation axis along a first direction, wherein, The first direction is the extension direction of the line of intersection between the spray surface and the horizontal plane in the first posture. When a first imaginary line is defined as a line extending through the center between the first nozzle array and the second nozzle array in the first posture when viewed from the first direction, and in a direction perpendicular to the spray surface in the first posture, the rotation axis is located on the side of the second nozzle array when viewed from the first imaginary line.

11. The liquid injection device as claimed in claim 10, wherein, The first posture is a recording posture in which the recording action is performed by spraying the first ink and the second ink onto the medium. The second posture is the maintenance posture for performing maintenance on the liquid injection head.

12. The liquid injection device as claimed in claim 10 or 11, wherein, In the second posture, the spray surface is parallel to the horizontal plane.

13. A liquid injection device comprising: A liquid jetting head having a jetting surface comprising a first nozzle array for jetting a first ink and a second nozzle array for jetting a second ink; The basket housing the liquid injection head. The liquid injection device is capable of holding the liquid injection head in a first orientation in which the injection surface is tilted relative to the horizontal plane. The dynamic surface tension of the first ink is greater than that of the second ink. In the first posture, the first nozzle array is positioned above the second nozzle array relative to the direction of gravity. The basket has a first contact point, which is the portion that contacts the floor surface when the basket is placed on the floor surface, as viewed in the first direction (i.e., the first direction) where the line of intersection between the spray surface and the horizontal plane in the first posture extends. Furthermore, when viewed in the first direction, it is located at one end in a third direction orthogonal to both the first direction and the direction of gravity. In the first posture, the distance between the first contact and the first nozzle array is greater than the distance between the first contact and the second nozzle array.

14. The liquid injection device as claimed in claim 13, wherein, The basket has a second contact point, which is the portion that contacts the floor surface when the basket is placed on the floor surface as viewed in the first direction, and is located at the other end in the third direction. When viewed in the first direction, the center of gravity of the liquid injection device is closer to the first contact point than the second contact point in the third direction.

15. The liquid injection device as claimed in claim 13 or 14, wherein, The basket has a second contact point, which is the portion that contacts the floor surface when the basket is placed on the floor surface as viewed in the first direction, and is located at the other end in the third direction. In the first posture, the distance between the second contact and the first nozzle array is greater than the distance between the second contact and the second nozzle array.

16. A liquid injection device comprising: A first liquid jetting head has a first jetting surface including a first nozzle for jetting first ink; The second liquid jetting head has a second jetting surface including a second nozzle for jetting a second ink; The third liquid ejection head has a third ejection surface including a third nozzle for ejecting a third ink. The dynamic surface tension of the third ink is greater than that of the second ink and less than that of the first ink. The first spray surface is configured such that the angle between the spray direction of the first ink ejected from the first nozzle and the direction of gravity is a first angle. The second spray surface is configured such that the angle between the spray direction of the second ink ejected from the second nozzle and the direction of gravity is a second angle greater than the first angle. The third spray surface is configured such that the angle between the spray direction of the third ink sprayed from the third nozzle and the direction of gravity is a third angle that is greater than the first angle and less than the second angle.

17. A liquid injection device comprising: A first liquid jetting head has a first jetting surface including a first nozzle for jetting first ink; The second liquid jetting head has a second jetting surface including a second nozzle for jetting a second ink; A first pressure regulating unit adjusts the pressure of the first ink supplied to the first nozzle. The second pressure regulating unit adjusts the pressure of the second ink supplied to the second nozzle. The dynamic surface tension of the first ink is greater than that of the second ink. The first spray surface is configured such that the angle between the spray direction of the first ink ejected from the first nozzle and the direction of gravity is a first angle. The second spray surface is configured such that the angle between the spray direction of the second ink ejected from the second nozzle and the direction of gravity is a second angle greater than the first angle. The first pressure regulating unit and the second pressure regulating unit are arranged in the same position with respect to the direction of gravity.

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