Liquid ejecting apparatus and liquid ejecting head

Abstract

A liquid ejecting apparatus and a liquid ejecting head capable of reducing a difference in thickening of ink between nozzle rows are provided. The liquid ejecting apparatus includes a liquid ejecting head having an ejecting surface including a first nozzle row that ejects a first ink and a second nozzle row that ejects a second ink, and a support body that supports the liquid ejecting head in a tilted posture in which the ejecting surface is tilted with respect to a horizontal plane. In a state in which the support body supports the liquid ejecting head in the tilted posture, the first nozzle row is located at a vertically upper position compared with the second nozzle row, and the second ink has a higher thickening resistance than the first ink.

Description

Technical Field

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

[0002] Liquid ejection devices, such as inkjet printers, generally have a liquid ejection head that ejects ink. The liquid ejection head has an ejection surface on which nozzles for ejecting ink are provided, and, for example, as disclosed in Patent Document 1, it is sometimes configured such that the ejection surface is tilted relative to a horizontal plane.

[0003] In the apparatus described in Patent Document 1, when multiple nozzle rows that spray different inks are arranged on the spraying surface, the multiple nozzles are positioned at different locations in the vertical direction. In this structure where multiple nozzle rows are positioned at different locations in the vertical direction, there is a problem that the difference in ink thickening between the nozzle rows increases due to this arrangement.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2020-6576 Summary of the Invention

[0005] To address the above-mentioned issues, the preferred embodiment of the present invention provides a liquid jetting apparatus 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; and a support body capable of supporting the liquid jetting head in an inclined posture with the jetting surface tilted relative to a horizontal plane, wherein, with the support body supporting the liquid jetting head in the inclined posture, the first nozzle array is located above the second nozzle array in the vertical direction, and the thickening resistance of the second ink is higher than that of the first ink.

[0006] A preferred embodiment of the present invention relates to a liquid jetting apparatus comprising: a first liquid jetting head having a first jetting surface including a plurality of first nozzles for jetting a first ink; a second liquid jetting head having a second jetting surface including a plurality of second nozzles for jetting a second ink; a first cover being concave and covering the first jetting surface in a first orientation where the angle between the first jetting surface and the horizontal plane is a first angle; and a second cover being concave and covering the second jetting surface in a second orientation where the angle between the second jetting surface and the horizontal plane is a second angle greater than the first angle, wherein the first ink and the second ink each contain a humectant, and the thickening resistance of the second ink is higher than that of the first ink.

[0007] The preferred embodiment of the present invention relates to a liquid jetting head having a jetting surface 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. In the liquid jetting head, the third nozzle array is located between the first nozzle array and the second nozzle array. The thickening resistance of the third ink is higher than that of the first ink and lower than that of the second ink. Attached Figure Description

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

[0009] Figure 2 This is a top view of the liquid injection head according to the first embodiment.

[0010] Figure 3 A diagram illustrating the liquid jet head during capping.

[0011] Figure 4 This is a top view of the liquid injection head according to the second embodiment.

[0012] Figure 5 This is a top view of the liquid injection head according to the third embodiment.

[0013] Figure 6 This is a top view of the liquid injection head according to the fourth embodiment.

[0014] Figure 7 This is a schematic diagram illustrating a structural example of the liquid injection device according to the fifth embodiment.

[0015] Figure 8 A diagram illustrating the first liquid injection head during capping.

[0016] Figure 9 A diagram illustrating the second liquid injection head during capping.

[0017] Figure 10 A schematic diagram illustrating the structure of the liquid injection device involved in Modified Example 1.

[0018] Figure 11 This is a top view of the liquid injection head of Modified Example 2. Detailed Implementation

[0019] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the dimensions and scales of the parts in the drawings differ appropriately from actual figures, and some parts are shown schematically for ease of understanding. Furthermore, unless otherwise specifically limited in the following description, the scope of the present invention is not limited to these embodiments.

[0020] In the following description, the intersecting X-axis, Y-axis, and Z-axis will be used appropriately. In the following text, one direction along the X-axis is the X1 direction, and the opposite direction is the X2 direction. Similarly, opposite directions along the Y-axis are the Y1 and Y2 directions. Opposite directions along the Z-axis are the Z1 and Z2 directions. Additionally, either the X1 or X2 direction is an example of a "first direction."

[0021] Here, the Z-axis is a vertical axis, and the Z2 direction corresponds to the downward direction in the vertical direction. Therefore, a plane orthogonal to the Z-axis is equivalent to a horizontal plane. Furthermore, in this embodiment, since the X-axis, Y-axis, and Z-axis are typically orthogonal to each other, the horizontal plane is defined by the X-axis and Y-axis. However, although the X-axis, Y-axis, and Z-axis are typically orthogonal to each other, this is not a limitation; for example, they may intersect at angles ranging from 80° to 100°.

[0022] Furthermore, in the following description, in addition to using the X-axis, Y-axis, and Z-axis, the V-axis and W-axis may sometimes be used. The V-axis and W-axis are axes inclined relative to the horizontal plane. Here, in this embodiment, the V-axis is an axis parallel to the normal of the injection surface FN in the tilted posture (or, in other words, the capping posture described later), orthogonal to the X-axis, and inclined relative to the Z-axis. The directions along the V-axis and opposite to each other are the V1 direction and the V2 direction. The V2 direction is the direction of the normal vector of the injection surface FN in the tilted posture (or, in other words, the capping posture described later). The W-axis is an axis orthogonal to both the X-axis and the V-axis. The directions along the W-axis and opposite to each other are the W1 direction and the W2 direction. The W1 direction or the W2 direction is an example of a "second direction".

[0023] 1. First Implementation Method

[0024] 1-1. Liquid injection device

[0025] Figure 1This is a schematic diagram illustrating a structural example of the liquid jetting apparatus 100 according to the first embodiment. The liquid jetting apparatus 100 is an inkjet printing apparatus that jets an ink, as an example of a liquid, onto a medium M as droplets. The liquid jetting apparatus 100 of this embodiment is a so-called row-type printing apparatus in which multiple nozzles for jetting ink are distributed across the entire width direction of the medium M. The medium M is typically printing paper. However, the medium M is not limited to printing paper; for example, it can be any printing material such as resin film or fabric.

[0026] The liquid injection device 100 includes: a liquid container 10, a control unit 20, a conveying mechanism 30, a liquid injection head 40, a support mechanism 50, and a maintenance mechanism 60.

[0027] The liquid container 10 stores the ink. Specific examples of the liquid container 10 include, for instance, a detachable box attached to the liquid dispensing device 100, a bag-shaped ink pouch formed of a flexible film, and an ink canister capable of being refilled. Furthermore, the type of ink stored in the liquid container 10 is arbitrary.

[0028] Although not illustrated, the liquid container 10 of this embodiment includes a first liquid container for storing a first ink, a second liquid container for storing a second ink, a third liquid container for storing a third ink, and a fourth liquid container for storing a fourth ink. The first ink, second ink, third ink, and fourth ink are all different from each other. In particular, the thickening resistance of the first ink, second ink, third ink, and fourth ink are all different. These inks will be described in detail later.

[0029] The control unit 20 controls the operation of various elements of the liquid injection device 100. The control unit 20 includes, for example, processing circuits such as a CPU (Central Processing Unit) or FPGA (Field Programmable Gate Array), and storage circuits such as semiconductor memory. Various programs and data are stored in this storage circuit. The processing circuit executes the programs and appropriately uses the data to achieve various controls.

[0030] The conveying mechanism 30, under the control of the control unit 20, conveys the medium M. Figure 1 In the example shown, the conveying mechanism 30 has a supply mechanism 31, a discharge mechanism 32, and a belt mechanism 33.

[0031] The supply mechanism 31 is a mechanism that supplies the medium M to the belt conveyor 33. Figure 1In the example shown, the supply mechanism 31 includes a first supply roller 31a and a second supply roller 31b. The first supply roller 31a and the second supply roller 31b are arranged in a parallel and contacting manner, and the medium M sandwiched between these rollers is conveyed in the Y2 direction.

[0032] The discharge mechanism 32 is a mechanism for discharging the medium M from the conveyor mechanism 33. Figure 1 In the example shown, the discharge mechanism 32 includes a first discharge roller 32a and a second discharge roller 32b. The first discharge roller 32a and the second discharge roller 32b are arranged in a parallel and contacting manner, and the medium M sandwiched between these rollers is conveyed in the Y2 direction.

[0033] The conveyor mechanism 33 is a mechanism that transports the medium M while maintaining it in a predetermined posture relative to the liquid injection head 40. Figure 1 In the example shown, the belt mechanism 33 includes a first conveyor roller 33a, a second conveyor roller 33b, and a conveyor belt 33c. The first conveyor roller 33a and the second conveyor roller 33b are arranged parallel to each other at positions separated along the Y-axis. The conveyor belt 33c is a seamless belt mounted on the first conveyor roller 33a and the second conveyor roller 33b, and rotates by the rotation of one or both of the first conveyor roller 33a and the second conveyor roller 33b. The outer peripheral surface of the conveyor belt 33c is charged, for example, by a charging mechanism (not shown), so that the medium M is electrostatically attracted to the outer peripheral surface of the conveyor belt 33c and is conveyed in the Y2 direction as the conveyor belt 33c rotates.

[0034] Under the control of the control unit 20, the liquid jet head 40 jets ink from the liquid container 10 toward the medium M in the Z2 direction. The liquid jet head 40 has multiple head chips 41. Each head chip 41 has multiple nozzles N, multiple pressure chambers C, and multiple drive elements E. Multiple nozzles N are disposed on the jetting surface FN of the liquid jet head 40. In this embodiment, the multiple nozzles N are arranged in a manner that spans the entire range of the medium M along the X-axis direction. That is, the liquid jet head 40 is a strip-shaped head in the X-axis direction. Pressure chambers C and drive elements E are respectively disposed for each nozzle N. The pressure chamber C is a space communicating with the nozzle N. The pressure chamber C is filled with ink supplied from the liquid container 10. The drive element E causes pressure variations in the ink within the pressure chamber C. The drive element E is, for example, a piezoelectric element that changes the volume of the pressure chamber C by deforming the wall of the pressure chamber C, or a heating element that generates bubbles within the pressure chamber C by heating the ink within the pressure chamber C. In the liquid ejection head 40, the pressure of the ink in the pressure chamber C is changed by the drive element E, thereby causing the ink in the pressure chamber C to be ejected from the nozzle N. Furthermore, the relationship between the arrangement of the multiple nozzles N and the type of ink will be described in detail later.

[0035] The support mechanism 50 is a mechanism that supports the liquid injection head 40. The support mechanism 50 has a support body 51. The support body 51 is a frame or other component that supports the liquid injection head 40, and the liquid injection head 40 is fixed to the support body 51 by screws or the like. The support body 51 can support the liquid injection head 40 in an attitude in which the injection surface FN is tilted relative to the horizontal plane. In the following text, the attitude in which the injection surface FN is tilted relative to the horizontal plane by the support body 51 will be referred to simply as the "tilted attitude".

[0036] In this embodiment, although the support mechanism 50 is not shown in the figure, it includes a drive mechanism that changes the position and orientation of the support body 51. This drive mechanism, under the control of the control unit 20, adjusts the position and orientation of the support body 51. Figure 1 The solid line in the image shows the state where the jet surface FN is parallel to the horizontal plane, and as shown in the image... Figure 1 The state of the spray surface FN, as shown by the double-dotted line, being tilted relative to the horizontal plane is switched. When the spray surface FN is parallel to the horizontal plane, printing on the medium M is performed by the liquid spray head 40. When the spray surface FN is tilted relative to the horizontal plane, maintenance of the liquid spray head 40 is performed by the maintenance mechanism 60.

[0037] Furthermore, the position of the support 51, with the injection surface FN tilted relative to the horizontal plane, is determined by the position of the cover 61 (described later) and is not limited to [specific location]. Figure 1 The example shown. For instance, when the cover is positioned adjacent to the liquid spray head 40 during printing in the X-axis direction, the support mechanism 50 is configured to allow the support body 51 to move in the X-axis direction. Alternatively, the support mechanism 50 may be a structure that does not change the position of the support body 51. In this case, after the spray surface FN is switched from a parallel state relative to the horizontal plane to an inclined state, the cover 61 (described later) can be moved toward the support body 51 in a manner that allows for the maintenance of the liquid spray head 40, which is performed by the maintenance mechanism 60.

[0038] The maintenance mechanism 60 is used in the maintenance operation of the liquid nozzle 40. The maintenance mechanism 60 includes a cover 61, a suction pump 62, and a waste liquid channel 63. The cover 61 is a concave component that covers the spray surface FN during the maintenance operation of the maintenance mechanism 60. During the maintenance operation, the cover 61 presses against the spray surface FN to form a closed space with the spray surface FN as a wall. The suction pump 62 is a mechanism that generates a negative pressure in the space between the cover 61 and the spray surface FN. This negative pressure forces the ink inside the liquid nozzle 40 from the multiple nozzles N into the cover 61 as a maintenance operation. The ink discharged into the cover 61 is discharged into a waste liquid container (not shown) via the waste liquid channel 63 by driving the suction pump 62 with the cover released. Through the above maintenance operation, the thickened ink inside the liquid nozzle 40 is discharged to the outside. Therefore, through regular maintenance, the ink within the liquid nozzle 40 is maintained in good condition. Additionally, the maintenance mechanism 60 can also perform a rinsing action (empty ejection action) by forcibly ejecting ink that does not directly contribute to printing from multiple nozzles N into the cover 61 via the drive element E. Furthermore, the maintenance mechanism 60 can also perform a pressurized cleaning action by pressurizing the flow channel upstream of the pressure chamber C of the liquid nozzle 40 using a pump or similar device that pressurizes the ink supplied from the liquid container 10 to the liquid nozzle 40, thereby discharging ink from the nozzles N.

[0039] 1-2. Ink

[0040] The first ink, the second ink, the third ink, and the fourth ink will be described below. Furthermore, in the following text, the first ink, the second ink, the third ink, and the fourth ink will be referred to simply as ink.

[0041] The ink contains water, colorant, and humectant. The ink can be either a dispersion or a solution. Furthermore, as long as the thickening resistance relationship described later is achieved, one of the first, second, third, and fourth inks may not contain a humectant.

[0042] Coloring materials are pigments or dyes. While not specifically limited, examples of pigments include black pigments such as carbon black; blue-green pigments such as CI pigments Blue 1, 2, 3, 15:3, 15:4, 15:34, 16, 22, 60, and CI Vat Blue 4, 60; CI pigments Red 5, 7, 12, 48(Ca), 48(Mn), 57(Ca), 57:1, 112, 122, 123, 168, 184, 202; and CI pigment Violet. The pigments include: magenta pigments (grade 19); yellow pigments (grades 1, 2, 3, 12, 13, 14C, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 110, 114, 119, 128, 129, 138, 150, 151, 154, 155, 180, 185); orange pigments (grades 36, 43); and green pigments (grades 7, 36). Each of these can be used individually or in combination of two or more.

[0043] As dyes, although not specifically limited, examples include, for instance, CI Disperse Yellow 3, 7, 8, 23, 39, 51, 54, 60, 71, 86; CI Disperse Orange 1, 1:1, 5, 20, 25, 25:1, 33, 56, 76; CI Disperse Brown 2; CI Disperse Red 11, 50, 53, 55, 55:1, 59, 60, 65, 70, 75, 93, 146, 158, 190, 190. CI Reduction Red 41; CI Disperse Violet 8, 17, 23, 27, 28, 29, 36, 57; CI Disperse Blue 19, 26, 26; CI Reduction Red 41; CI Disperse Violet 8, 17, 23, 27, 28, 29, 36, 57; CI Disperse Blue 19, 26, 26; CI Disperse Blue 1, 35, 55, 56, 58, 64, 64; CI Disperse Blue 1, 72, 72; CI Disperse Blue 1, 81, 81; CI Disperse Blue 1, 91, 95, 108, 131, 141, 145, 359; CI Solvent Blue 36, 63, 105, 111, etc. Among these, one can be used alone or in combination of two or more.

[0044] A humectant is a material with a moisture absorption rate of 100% or higher. Moisture absorption rate is defined as (moisture absorption rate) = (mass of humectant after standing - initial mass of humectant) / (initial mass of humectant). The moisture absorption rate is determined, for example, by placing 4g of the sample into a 50ml glass screw-top flask and allowing it to stand in a high-humidity environment (40°C, 97% RH) in a constant-temperature bath (ETAC: FX430N). The mass of the sample is measured using an electronic balance (A&D: GF600) until the change in mass disappears. Here, the mass of the sample at the start of the measurement is called the "initial mass of the humectant," and the mass of the sample at the end of the measurement is called the "mass of the humectant after standing." Furthermore, temperature and humidity are measured, for example, using a thermo-hygrometer (T&D: TR-72U).

[0045] While not particularly limited, examples of humectants include glycerin, 2-pyrrolidone, urea, triethanolamine, propylene glycol, 1-(2-hydroxyethyl)-2-pyrrolidone, trimethylolpropane, triethylene glycol, 1,5-pentanediol, triethylene glycol monomethyl ether, and amino coatings. One of these can be used alone or in combination with two or more. From the viewpoint of high hygroscopicity, glycerin, 2-pyrrolidone, triethanolamine, propylene glycol, 1-(2-hydroxyethyl)-2-pyrrolidone, and trimethylolpropane are preferred as humectants.

[0046] In the aforementioned measurement methods, the moisture absorption rate of glycerol was 246%. The moisture absorption rate of 2-pyrrolidone was 199%. The moisture absorption rate of urea was 316%. The moisture absorption rate of triethanolamine was 150%. The moisture absorption rate of propylene glycol was 168%, and the moisture absorption rate of 1-(2-hydroxyethyl)-2-pyrrolidone was 159%. The moisture absorption rate of trimethylolpropane was 111%.

[0047] In addition to water, coloring agents, and humectants, inks may also contain resins, surfactants, dispersants, stabilizers, and other additives.

[0048] The first, second, third, and fourth inks, containing the above-mentioned components, exhibit different thickening resistances. Specifically, the thickening resistances of these inks are listed in ascending order: first ink, third ink, fourth ink, and second ink. "Thickening resistance" refers to the property of difficulty in thickening, defined, for example, by the rate of increase in viscosity after 24 hours at room temperature (25°C) and 20% humidity. Inks with lower viscosity increases are considered to have higher thickening resistance. However, the ambient temperature, humidity, and storage time used to measure thickening resistance are not limited to these parameters.

[0049] Preferably, the effective moisture content of the second ink is lower than that of the first ink. In this case, the thickening resistance of the second ink is higher than that of the first ink. Similarly, it is preferable that the effective moisture content of the third ink is greater than that of the second ink and less than that of the first ink. Furthermore, it is preferable that the effective moisture content of the fourth ink is greater than that of the second ink and less than that of the third ink. In this manner, it is preferable that the effective moisture content of these inks, from smallest to largest, is in the order of the second ink, the fourth ink, the third ink, and the first ink.

[0050] The "effective moisture content" is calculated using the following formula.

[0051] (Effective moisture content [wt%]) = (Water content [wt%]) - {(Moisture absorption rate of humectant) × (Hygroscopicity of humectant [wt%])}

[0052] Here, when the humectant is a mixture of two or more humectants, the "hygroscopic rate of the humectant" in the above formula is the hygroscopic rate of the mixture, which can be determined, for example, by the aforementioned measurement method. Furthermore, when using a mixture of n kinds (n is a natural number of 2 or more) of humectants [1] to humectant [n], the general effective moisture content can also be calculated using the following formula.

[0053] (Effective moisture content [wt%]) = (Water content [wt%]) - {(Moisture absorption rate of humectant [1]) × (Moisture content rate of humectant [1])} ... - {(Moisture absorption rate of humectant [n]) × (Moisture content rate of humectant [n])}

[0054] Furthermore, from the viewpoint of effectively reducing the thickening of the second ink, it is preferable that the effective moisture content of the first ink is more than twice the effective moisture content of the second ink, and more preferably more than three times.

[0055] Further, preferably, the hygroscopicity of the second ink is higher than that of the first ink. In this case, the thickening resistance of the second ink is higher than that of the first ink. According to the same viewpoint, preferably, the hygroscopicity of the third ink is higher than that of the first ink and lower than that of the second ink. Furthermore, preferably, the hygroscopicity of the fourth ink is higher than that of the third ink and lower than that of the second ink. In this way, it is preferable that the hygroscopicity of these inks is in the order of second ink, fourth ink, third ink, and first ink, from highest to lowest.

[0056] The term "hygroscopicity" refers to the property of easily retaining water, and is defined as the product of the hygroscopicity rate of the humectant and the humectant content in the ink. The larger the value of this product, the higher the hygroscopicity. When the ink contains multiple humectants, "hygroscopicity" is defined as the product of the hygroscopicity rate of the mixture of the multiple humectants and the content of the mixture in the ink. Furthermore, when using a mixture of n kinds (n is a natural number of 2 or more) of humectants [1] to humectant [n], the general hygroscopicity is defined as {(hygroscopicity rate of humectant [1]) × (content of humectant [1] [wt%])}...-{(hygroscopicity rate of humectant [n]) × (content of humectant [n] [wt%])}.

[0057] 1-3. Liquid injection head

[0058] Figure 2 This is a top view of the liquid injection head 40 according to the first embodiment. Figure 2 The image schematically illustrates a top-down view of the liquid injection head 40 when it is tilted, i.e., when the cap is pressed. For example... Figure 2 As shown, the liquid injection head 40 has three head chips 41_1, three head chips 41_2, three head chips 41_3, and three head chips 41_4 as head chips 41. These sets are arranged in the W2 direction in the order of the set of three head chips 41_1, the set of three head chips 41_3, the set of three head chips 41_4, and the set of three head chips 41_2. Furthermore, a set of head chips 41 can contain two or more head chips 41. Additionally, the liquid injection head 40 can have only one head chip 41_1, and the same applies to head chips 42_2 to 42_4.

[0059] Although not shown, the head chip 41 includes a nozzle plate on which a plurality of nozzles N are formed. Furthermore, the spray surface FN is a surface that includes the surface of the nozzle plate. Additionally, when the surfaces of the components constituting the liquid spray head 40, excluding the nozzle plate, are substantially continuous with the surface of the nozzle plate, the spray surface FN may include not only the surface of the nozzle plate but also the surfaces of the components constituting the liquid spray head 40 other than the nozzle plate. Here, "substantially continuous" means that even if there are small gaps or step differences between the surface of the nozzle plate and the surfaces of the components constituting the liquid spray head 40 other than the nozzle plate, these surfaces can be considered as continuous surfaces.

[0060] Three head chips 41_1 are arranged along the X-axis. However, although the two head chips 41_1 located at opposite ends along the X-axis are arranged side-by-side on the same straight line along the X-axis, the remaining head chip 41_1 is located in the W1 direction relative to the other two. Each head chip 41_1 has a nozzle array LN_1, which is composed of a plurality of nozzles N_1 arranged along the X-axis. Nozzle N_1 is a nozzle N for ejecting the first ink.

[0061] Three head chips 41_2 are arranged along the X-axis. However, although the two head chips 41_2 located at opposite ends along the X-axis are arranged side-by-side on the same straight line along the X-axis, the remaining head chip 41_2 is located in the W1 direction relative to the other two. Each head chip 41_2 has a nozzle array LN_2, which is composed of a plurality of nozzles N_2 arranged along the X-axis. Nozzle N_2 is a nozzle N for ejecting a second ink.

[0062] Three head chips 41_3 are arranged along the X-axis. However, although the two head chips 41_3 located at opposite ends along the X-axis are arranged side-by-side on the same straight line along the X-axis, the remaining head chip 41_3 is located in the W1 direction relative to the other two. Each head chip 41_3 has a nozzle array LN_3, which is composed of a plurality of nozzles N_3 arranged along the X-axis. Nozzle N_3 is a nozzle N for ejecting a third ink.

[0063] Three head chips 41_4 are arranged along the X-axis. However, although the two head chips 41_4 located at opposite ends along the X-axis are arranged side-by-side on the same straight line along the X-axis, the remaining head chip 41_4 is located in the W1 direction relative to the other two. Each head chip 41_4 has a nozzle array LN_4, which is composed of a plurality of nozzles N_4 arranged along the X-axis. Nozzle N_4 is a nozzle N for ejecting a fourth ink.

[0064] like Figure 2 As shown, the liquid injection head 40 has three groups, namely, head chips 41_1, 41_3, 41_4, and 41_2 arranged in the W2 direction in this order. Furthermore, in the following text, there may be a case where the nozzle rows LN_1, LN_2, LN_3, and LN_4 are not distinguished and are simply referred to as nozzle row LN.

[0065] Figure 3 The diagram schematically illustrates the liquid injection head 40 during capping. (See figure.) Figure 3 As shown, during capping, the spray surface FN is covered by the cap 61 at an angle θ relative to the horizontal plane HP.

[0066] The cover 61 is concave, forming a closed space between itself and the spray surface FN. More specifically, the cover 61 has a bottom wall 61a and a side wall 61b extending from the outer periphery of the bottom wall 61a across the entire area. A recess 61c is formed by the bottom wall 61a and the side wall 61b. A discharge port 61d communicating with the waste liquid flow channel 63 is formed on the bottom wall 61a. The cover 61 forms a closed space surrounded by the bottom wall 61a, the side wall 61b, and the spray surface FN. That is, the opening through the recess 61c is blocked by the spray surface FN, thereby forming a closed space. In addition, within this closed space, strictly speaking, there are multiple nozzles N and a discharge port 61d. Specifically, the nozzles N1 of nozzle row LN_1, N2 of nozzle row LN_2, N3 of nozzle row LN_3, and N4 of nozzle row LN_4 open toward the recess 61c. Furthermore, during capping, when viewed along the V-axis, if the opening of the recess 61c of the cap 61 is opposite to the plurality of nozzles N, a gap can also be formed between the side wall 61b and the liquid injection head 40. That is, the recess 61c can be opened to the atmosphere during capping, thus preventing the formation of this enclosed space.

[0067] The length L1 of the cap 61 along the W-axis is greater than the length L2 of the cap 61 along the V-axis. Therefore, compared to a structure where length L2 is greater than length L1, the cap 61 can be miniaturized. Furthermore, in a structure where length L1 is greater than length L2, the spray surface FN is more susceptible to the influence of the absorbent liquid LD biased within the cap 61 as described later. Therefore, in a structure where length L1 is greater than length L2, the effect achieved by the order of ink thickening resistance as described later can be significantly obtained.

[0068] exist Figure 3 In the example shown, the bottom wall 61a is plate-shaped, extending in a direction orthogonal to the V-axis, that is, parallel to the spray surface FN. Here, the bottom surface of the bottom wall 61a is inclined relative to the horizontal plane HP along the spray surface FN during capping. The side wall 61b extends from the outer periphery of the bottom wall 61a, spanning the entire circumference, in the V1 direction, that is, in a direction opposite to the normal vector of the spray surface FN. Figure 2 as well as Figure 3As shown, during capping, the top of the sidewall 61b contacts the sealing area SR of the spray surface FN, thereby blocking the opening of the recess 61c with the spray surface FN of the liquid spray head 40. Alternatively, the opening of the recess 61c can be blocked by the liquid spray head 40 by contacting a portion near the outer peripheral edge of the spray surface FN of the liquid spray head 40.

[0069] A moisture-absorbing liquid LD is disposed in the recess 61c. The moisture-absorbing liquid LD is, for example, ink sprayed from the liquid jet head 40 into the recess 61c by a rinsing action. This ink remains in the lower part of the recess 61c due to gravity as the bottom wall 61a tilts. Furthermore, the moisture in this ink slowly evaporates over time, except during the capping process. Therefore, the moisture content of the moisture-absorbing liquid LD is lower than that of the ink in the liquid jet head 40. In other words, the moisture-absorbing liquid LD has a higher humectant content than the ink in the liquid jet head 40. Therefore, the moisture absorption of the moisture-absorbing liquid LD is higher than that of the ink in the liquid jet head 40. Alternatively, the moisture-absorbing liquid LD may be a liquid containing a humectant such as glycerin, which has moisturizing properties and is disposed separately from the ink from the liquid jet head 40. Furthermore, the moisture-absorbing liquid LD may also be ink discharged by a pressure rinsing action or a suction rinsing action.

[0070] During capping, the vertical positions of the nozzle arrays LN of the liquid injection head 40, from bottom to top, are in the order of nozzle arrays LN_2, LN_4, LN_3, and LN_1. That is, during capping, the position P3 of nozzle array LN_3 is lower than the position P1 of nozzle array LN_1, the position P4 of nozzle array LN_4 is lower than the position P3 of nozzle array LN_3, and the position P2 of nozzle array LN_2 is lower than the position P4 of nozzle array LN_4. Furthermore, the position of nozzle array LN is the lowest vertically positioned nozzle N among the multiple nozzles N contained within it.

[0071] In addition, such as Figure 2 as well as Figure 3 As shown, when the liquid injection head 40 is in an inclined position, when viewed along the direction of the intersection of the injection surface FN and the horizontal plane HP, the nozzle array LN_1 is arranged in the W1 direction with a gap relative to the nozzle array LN_3, the nozzle array LN_3 is arranged in the W1 direction with a gap relative to the nozzle array LN_4, and the nozzle array LN_4 is arranged in the W1 direction with a gap relative to the nozzle array LN_2.

[0072] Therefore, during capping, the distances between each nozzle row LN of the liquid jet head 40 and the aforementioned absorbing liquid LD, from closest to farthest, are nozzle rows LN_2, LN_4, LN_3, and LN_1. As a result, if the influence of the absorbing liquid LD on each nozzle row of the liquid jet head 40 is arranged from largest to smallest, the order is nozzle rows LN_2, LN_4, LN_3, and LN_1. Therefore, assuming that the thickening resistance of the ink in all nozzle rows of the liquid jet head 40 is equal, the difference in ink thickening between nozzle rows becomes larger.

[0073] Therefore, as described above, the thickening resistance of the ink in the liquid ejector head 40 increases in the order of first ink, third ink, fourth ink, and second ink. This reduces the difference in ink thickening between nozzle rows. As a result, during the flushing action performed after capping to expel ink thickened in nozzle N during capping, the amount of ink ejected from the multiple nozzle rows of the liquid ejector head 40 can be made equal to each other. This saves time and effort compared to adjusting the amount of ink ejected from each of the multiple nozzle rows of the liquid ejector head 40 for each individual nozzle row, taking into account the thickening differences between them. Incidentally, for example, in a configuration where the lowest thickening resistance first ink is ejected from the lowest vertically positioned nozzle array LN_2, and the highest thickening resistance second ink is ejected from the highest vertically positioned nozzle array LN_1, the first ink in nozzle N_2 of nozzle array LN_2 thickens to a greater degree than the second ink in nozzle N_1 of nozzle array LN_1. Therefore, if a large amount of ink is discharged equally from each nozzle array LN_1 and LN_2 via a rinsing action according to the thickness of the first ink in nozzle N_2 of nozzle array LN_2, it is possible that even normal ink that has not yet thickened may be excessively discharged from nozzle array LN_1, which has a lower degree of thickening. On the other hand, as mentioned above, since the thickening resistance of the ink in the liquid jet head 40 is in the order of first ink, third ink, fourth ink, and second ink from low to high, the difference in thickening of the ink between the nozzle rows is small. Therefore, even if an equal amount of ink is discharged from each nozzle row LN_1 to LN_4 through the rinsing action, the normal ink will not be discharged in excess, resulting in reduced ink waste.

[0074] As described above, the liquid jetting device 100 includes a liquid jetting head 40 and a support body 51. The liquid jetting head 40 has a jetting surface FN, which includes, for example, a "first nozzle array" (LN_1) for jetting a first ink and, for example, a "second nozzle array" (LN_2) for jetting a second ink. The support body 51 can support the liquid jetting head 40 in an inclined posture with the jetting surface FN tilted relative to the horizontal plane HP.

[0075] Here, with the support body 51 supporting the liquid injection head 40 in this tilted posture, the nozzle array LN_1 is located above the nozzle array LN_2 in the vertical direction. Based on this, the thickening resistance of the second ink is higher than that of the first ink.

[0076] In the liquid jetting device 100 described above, when an object with hygroscopic properties for both the first and second inks is located vertically below the jetting surface FN, the distance between this object and the nozzle array LN_2 is shorter than the distance between the object and the nozzle array LN_1. Therefore, the nozzle array LN_2 is more significantly affected by the hygroscopic properties of this object compared to the nozzle array LN_1. In the liquid jetting device 100, since the thickening resistance of the second ink is higher than that of the first ink, the thickening of the second ink caused by this object can be reduced. Therefore, the difference between the thickening of the first ink and the thickening of the second ink can be reduced. As a result, ink waste or image quality degradation caused by thickening can be reduced. Furthermore, although the object is a hygroscopic liquid LD in this embodiment, it is not limited to this; for example, it could also be a medium M, etc.

[0077] As described above, the liquid jetting device 100 also includes a concave cap 61 that covers the jetting surface FN when the support body 51 supports the liquid jetting head 40 in an inclined position. Furthermore, one or both of the first ink and the second ink contain a humectant. Here, "cap 61 covers the jetting surface FN" means that, at least when viewed in the normal direction of the jetting surface FN, the concave portion 61c of the cap 61 is aligned with the plurality of nozzles N disposed on the jetting surface FN; it may also include a structure in which a gap is formed between the sidewall 61b and the liquid jetting head 40 when the cap is pressed down.

[0078] Inside the cover 61, ink ejected from the liquid jet head 40 due to rinsing, etc., remains as a hygroscopic liquid, an example of an object with hygroscopic properties for both the first and second inks. Here, the cover 61 is tilted relative to the horizontal plane HP along the jetting surface FN. Therefore, since the hygroscopic liquid is biased towards the lower part of the cover 61, it is located vertically lower than the jetting surface FN. As a result, nozzle line LN_2 is more affected by the hygroscopic liquid than nozzle line LN_1. Therefore, by making the thickening resistance of the second ink higher than that of the first ink, the difference in thickening between the first and second inks can be reduced.

[0079] In this embodiment, as described above, the support 51 can change the angle between the jetting surface FN and the horizontal plane HP. Here, the angle θ0 between the jetting surface FN and the horizontal plane HP during recording of the medium M is smaller than the angle θ between the jetting surface FN and the horizontal plane HP in the tilted position. Therefore, the recording operation for the medium M can be performed stably, resulting in improved image quality. Furthermore, the angle θ between the jetting surface FN and the horizontal plane HP in the tilted position can be increased. As a result, a wiping operation to wipe the ink adhering to the jetting surface FN by a wiping member (not shown) can be effectively performed, or air bubbles in the liquid jetting head 40 can be effectively removed by a maintenance operation.

[0080] Furthermore, as described above, the cover 61 has a bottom wall 61a and a side wall 61b extending from the outer periphery of the bottom wall 61a across the entire area. Moreover, the cover 61 forms a closed space surrounded by the bottom wall 61a, the side wall 61b, and the spray surface FN, and has openings for a plurality of nozzles N_1 constituting nozzle array LN_1 and a plurality of nozzles N_2 constituting nozzle array LN_2. Therefore, compared to a structure with an open space between the cover 61 and the spray surface FN, the humidity inside the cover 61 can be increased. As a result, the thickening of both the first ink and the second ink can be reduced.

[0081] Furthermore, as mentioned above, the spray surface FN also has an example of a "third nozzle array," namely LN_3, for spraying the third ink. With the support body 51 supporting the liquid spray head 40 in an inclined position, nozzle array LN_3 is located vertically between nozzle arrays LN_1 and LN_2. The thickening resistance of the third ink is higher than that of the first ink but lower than that of the second ink. Therefore, the difference in thickening between the first or second ink and the third ink can be reduced.

[0082] Furthermore, as described above, the spray surface FN also has an example of a "fourth nozzle array," namely nozzle array LN_4, for spraying the fourth ink. With the support body 51 supporting the liquid spray head 40 in an inclined position, nozzle array LN_4 is located vertically between nozzle arrays LN_2 and LN_3. The thickening resistance of the fourth ink is lower than that of the second ink but higher than that of the third ink. Therefore, the difference in thickening between the first, second, or third ink and the fourth ink can be reduced.

[0083] Furthermore, as described above, with the support body 51 supporting the liquid injection head 40 in an inclined position, the respective arrangement directions of the nozzle arrays LN_1 and LN_2 intersect with the W1 or W2 direction, which is orthogonal to the X1 or X2 direction along the injection surface FN. Additionally, the X1 or X2 direction is an example of a "first direction," and is the direction along the intersection of the injection surface FN and the horizontal plane HP. The W1 or W2 direction is an example of a "second direction."

[0084] Furthermore, as mentioned above, it is preferable that during the rinsing operation, the discharge amount of the first ink ejected from nozzle line LN_1 is equal to the discharge amount of the second ink ejected from nozzle line LN_2. Therefore, ink waste can be reduced. Here, "equal to" means, in addition to cases of strict equality, also includes cases with a difference of less than 10%.

[0085] 2. Second Implementation Method

[0086] The second embodiment of the present invention will now be described. Elements that function or have the same effect as those in the first embodiment as illustrated below will be referred to by the same symbols used in the description of the first embodiment, and detailed descriptions of each will be omitted as appropriate.

[0087] Figure 4 This is a top view of the liquid injection head 40A according to the second embodiment. Figure 4 The diagram schematically shows the liquid injection head 40A when viewed from above, i.e., when the liquid injection head 40A is tilted during capping. In this embodiment, except that the liquid injection head 40A is provided instead of the liquid injection head 40, everything else is substantially the same as in the first embodiment described above.

[0088] The liquid injection head 40A is composed of a plurality of heads 42A arranged side by side along the X-axis. Although the liquid injection head 40A of this embodiment is composed of two heads 42A, the liquid injection head 40A may have one or more heads 42A. In addition, the plurality of heads 42A may also be integrated. That is, the liquid injection head 40A may also be composed of a single head formed by integrating the plurality of heads 42A.

[0089] Each head 42A has six head chips 41A arranged along the X-axis. Furthermore, the number of head chips 41A in a head 42A can be five or fewer, or seven or more. Additionally, at least two of the six head chips 41A can be integrated.

[0090] Each head chip 41A has nozzle arrays LN_1, LN_2, LN_3, and LN_4 extending in a direction inclined relative to the W-axis. Nozzle array LN_1 consists of multiple nozzles N_1 arranged in a direction inclined relative to the W-axis. Nozzle N_1 is a nozzle N for ejecting a first ink. Nozzle array LN_2 consists of multiple nozzles N_2 arranged in a direction inclined relative to the W-axis. Nozzle N_2 is a nozzle N for ejecting a second ink. Nozzle array LN_3 consists of multiple nozzles N_3 arranged in a direction inclined relative to the W-axis. Nozzle N_3 is a nozzle N for ejecting a third ink. Nozzle array LN_4 consists of multiple nozzles N_4 arranged in a direction inclined relative to the W-axis. Nozzle N_4 is a nozzle N for ejecting a fourth ink.

[0091] Here, nozzle arrays LN_1 and LN_4 are arranged in a straight line along a direction inclined relative to the W-axis, with nozzle array LN_1 positioned in the W1 direction relative to nozzle array LN_4. Nozzle arrays LN_2 and LN_3 are arranged in a straight line along a direction inclined relative to the W-axis at a position relative to nozzle arrays LN_1 and LN_4 in the X1 direction, with nozzle array LN_3 positioned in the W1 direction relative to nozzle array LN_2.

[0092] A cover 61 (not shown) is provided for each head 42A, and the sidewall 61b of the cover 61 is... Figure 4 The sealing area SR shown corresponds to the contact area of ​​each head 42A. Alternatively, the sealing area SR may not be in contact with the side wall 61b of the cover 61.

[0093] During capping, the vertical positions of the nozzle arrays LN of the liquid injection head 40A, from bottom to top, are in the order of nozzle arrays LN_2, LN_4, LN_3, and LN_1. That is, during capping, the position P3 of nozzle array LN_3 is lower than the position P1 of nozzle array LN_1, the position P4 of nozzle array LN_4 is lower than the position P3 of nozzle array LN_3, and the position P2 of nozzle array LN_2 is lower than the position P4 of nozzle array LN_4.

[0094] Even with the second embodiment described above, the difference in thickening between the first ink and the second ink can be reduced in the same way as in the first embodiment. In this embodiment, when the support 51 supports the liquid jet head 40A in an inclined position, when viewed along the direction of the intersection of the jet surface FN and the horizontal plane HP, a portion of one of the nozzle arrays LN_1 and LN_2 overlaps with at least a portion of the other. Here, as described above, the position of the nozzle array LN is the position of the lowest vertical nozzle N among the plurality of nozzles N included in the nozzle array LN. Therefore, for example, the lowest vertical nozzle N_1 among the plurality of nozzles N_1 in the nozzle array LN_1 is located above the lowest vertical nozzle N_2 among the plurality of nozzles N_2 in the nozzle array LN_2. That is, the position P1 of the lowest nozzle N_1 is located above the lowest vertical nozzle N_2.

[0095] 3. Third Implementation Method

[0096] The third embodiment of the present invention will now be described. Elements that function or operate the same as those in the first embodiment as illustrated below will be referred to by the same symbols used in the description of the first embodiment, and detailed descriptions of each will be omitted as appropriate.

[0097] Figure 5 This is a top view of the liquid injection head 40B according to the third embodiment. Figure 5 The diagram schematically shows the liquid injection head 40B when viewed from above, i.e., when the liquid injection head 40B is tilted during capping. In this embodiment, except that the liquid injection head 40B is provided instead of the liquid injection head 40, everything else is substantially the same as in the first embodiment described above.

[0098] The liquid injection head 40B is composed of a plurality of heads 42B arranged side by side along the X-axis. Although the liquid injection head 40B of this embodiment is composed of two heads 42B, the liquid injection head 40B may have one or more heads 42B. In addition, the plurality of heads 42B may also be integrated. That is, the liquid injection head 40B may also be composed of a single head formed by integrating the plurality of heads 42B.

[0099] Each head 42B has nine head chips 41B arranged along the X-axis. Furthermore, the number of head chips 41B in each head 42B can be eight or less, or ten or more. Additionally, at least two of the nine head chips 41B can be integrated.

[0100] Each head chip 41B has nozzle arrays LN_1 and LN_2 extending in a direction inclined relative to the W-axis. Nozzle array LN_1 is composed of nozzles N_1 arranged in a direction inclined relative to the W-axis. Nozzle array LN_1 ejects a first ink. Nozzle N_1 is a nozzle N that ejects the first ink. Nozzle array LN_2 is composed of nozzles N_2 arranged in a direction inclined relative to the W-axis. Nozzle array LN_2 ejects a second ink.

[0101] Here, nozzle arrays LN_1 and LN_2 are arranged to be staggered from each other in both the arrangement direction of the nozzles N and the direction orthogonal to that arrangement direction. That is, when the support body 51 supports the liquid injection head 40B in an inclined position, when viewed along the direction of the intersection of the injection surface FN and the horizontal plane HP, a portion of one of the nozzle arrays LN_1 and LN_2 is repeated by at least a portion of the other. Moreover, the lowermost nozzle N_1 in the vertical direction among the plurality of nozzles N_1 in nozzle array LN_1 is located above the lowermost nozzle N_2 in the vertical direction among the plurality of nozzles N_2 in nozzle array LN_2. That is, the position P1 of the lowermost nozzle N_1 is located above the position P2 of the lowermost nozzle N_2 in the vertical direction.

[0102] A cover 61 (not shown) is provided for each head 42, and the sidewall 61b of the cover 61 is... Figure 5 The sealing area SR shown corresponds to the contact of each head 42B. Alternatively, the sealing area SR and the side wall 61b of the cover 61 may not be in contact.

[0103] Even with the third embodiment described above, the difference in thickening between the first ink and the second ink can be reduced in the same way as with the first embodiment described above.

[0104] 4. Fourth Implementation Method

[0105] The fourth embodiment of the present invention will now be described. Elements that function or operate the same as those in the first embodiment as illustrated below will be referred to by the same symbols used in the description of the first embodiment, and detailed descriptions of each will be omitted as appropriate.

[0106] Figure 6 This is a top view of the liquid injection head 40C according to the fourth embodiment. Figure 6 The diagram schematically shows the liquid jet head 40C when viewed from above, i.e., when the liquid jet head 40B is in an inclined position. In this embodiment, except that the liquid jet head 40C is provided instead of the liquid jet head 40, everything else is the same as in the first embodiment described above.

[0107] The liquid injection head 40C consists of two heads 43 and one head 44. Alternatively, one or both of the two heads 43 can be integrated with the head 44. Furthermore, the number of heads 43 and heads 44 is arbitrary, and there can be two or more heads 43 and two or more heads 44 arranged in an alternating pattern along the X-axis. Further, the heads 43 and heads 44 can also be arranged at the same position about the W1 direction.

[0108] Each head 43 has head chips 41a, 41b, 41c, and 41d. These head chips are arranged in the W1 direction in the order of head chip 41b, head chip 41d, head chip 41c, and head chip 41a. In addition, at least two of the head chips 41a, 41b, 41c, and 41d can also be integrated.

[0109] Head chip 41a has a nozzle array LN_1 consisting of a plurality of nozzles N_1 arranged along the X-axis. Nozzle N_1 is a nozzle N for ejecting a first ink. Head chip 41b has a nozzle array LN_2 consisting of a plurality of nozzles N_2 arranged along the X-axis. Nozzle array LN_2 is a nozzle N for ejecting a second ink. Head chip 41c has a nozzle array LN_3 consisting of a plurality of nozzles N_3 arranged along the X-axis. Nozzle N_3 is a nozzle N for ejecting a third ink. Head chip 41d has a nozzle array LN_4 consisting of a plurality of nozzles N_4 arranged along the X-axis. Nozzle array LN_4 is a nozzle N for ejecting a fourth ink.

[0110] Here, the lengths of the head chips 41a, 41b, 41c, and 41d along the X-axis are arranged from longest to shortest as head chip 41b, head chip 41d, head chip 41c, and head chip 41a.

[0111] Except for a 180° difference in orientation around the V-axis, with the structure changing accordingly, head 44 is otherwise identical to head 43. Specifically, head 44 has head chips 41e, 41f, 41g, and 41h. These head chips are arranged sequentially in the W1 direction according to head chip 41f, head chip 41h, head chip 41g, and head chip 41e. Furthermore, at least two of head chips 41e, 41f, 41g, and 41h can be integrated.

[0112] Head chip 41e has a nozzle array LN_1 consisting of a plurality of nozzles N_1 arranged along the X-axis. Nozzle N_1 is a nozzle N for ejecting a first ink. Head chip 41f has a nozzle array LN_2 consisting of a plurality of nozzles N_2 arranged along the X-axis. Nozzle array LN_2 is a nozzle N for ejecting a second ink. Head chip 41g has a nozzle array LN_3 consisting of a plurality of nozzles N_3 arranged along the X-axis. Nozzle N_3 is a nozzle N for ejecting a third ink. Head chip 41h has a nozzle array LN_4 consisting of a plurality of nozzles N_4 arranged along the X-axis. Nozzle array LN_4 is a nozzle N for ejecting a fourth ink.

[0113] Here, the lengths of the head chips 41e, 41f, 41g, and 41h along the X-axis are arranged from longest to shortest as head chip 41e, head chip 41g, head chip 41h, and head chip 41f.

[0114] A cover 61 (not shown) is provided for each head 43, 44, and the sidewall 61b of the cover 61 is... Figure 6 The sealing areas SR corresponding to each head 43, 44 are in contact. Alternatively, the sealing areas SR and the side wall 61b of the cover 61 may not be in contact.

[0115] When considering the head 43 covered by a cover 61, the vertical positions of the nozzle rows LN, from bottom to top, are nozzle rows LN_2, LN_4, LN_3, and LN_1. Furthermore, even when considering the head 44 covered by a cover 61, the vertical positions of the nozzle rows LN, from bottom to top, are also in the same order: nozzle rows LN_2, LN_4, LN_3, and LN_1.

[0116] Even according to the fourth embodiment described above, the difference in thickening between the first ink and the second ink can be reduced in the same way as in the first embodiment described above.

[0117] 5. Fifth Implementation Method

[0118] The fifth embodiment of the present invention will now be described. Elements that function or operate the same as those in the first embodiment as illustrated below will be referred to by the same symbols used in the description of the first embodiment, and detailed descriptions of each will be omitted as appropriate.

[0119] Figure 7 The diagram below shows a schematic representation of the structure of the liquid injection device 100D according to the fifth embodiment. In the liquid injection device 100D, except that it has a conveying mechanism 30D, multiple liquid injection heads 40D_1 to 40D_4, a support mechanism 50D, and a maintenance mechanism 60D instead of a conveying mechanism 30, a liquid injection head 40, a support mechanism 50, and a maintenance mechanism 60, the rest are the same as the liquid injection device 100 of the first embodiment described above. Liquid injection head 40D_1 is an example of a "first liquid injection head". Liquid injection head 40D_2 is an example of a "second liquid injection head". Liquid injection head 40D_3 is an example of a "third liquid injection head". Liquid injection head 40D_4 is an example of a "fourth liquid injection head". Furthermore, in the following text, there may be instances where liquid injection heads 40D_1 to 40D_4 are not distinguished and are simply referred to as liquid injection head 40D.

[0120] like Figure 7 As shown, the conveying mechanism 30D includes a roller 34 for conveying the medium M while it is adsorbed onto its outer peripheral surface. The roller 34 is a cylindrical or cylindrical component with an outer peripheral surface surrounding a central axis AX parallel to the X-axis. The roller 34 is driven to rotate around the central axis AX by a drive mechanism such as a motor (not shown). The outer peripheral surface of the roller 34 is charged by a charge carrier (not shown). Using the electrostatic force generated by this charge, the medium M is electrostatically adsorbed onto the outer peripheral surface of the roller 34.

[0121] Liquid injection heads 40D_1, 40D_2, 40D_3, and 40D_4 are respectively positioned opposite the outer peripheral surface of the roller 34. Liquid injection heads 40D_1, 40D_2, 40D_3, and 40D_4 are configured in the same manner as the liquid injection head 40 of the first embodiment described above.

[0122] However, the orientations around the axis parallel to the X-axis differ in liquid injection heads 40D_1, 40D_2, 40D_3, and 40D_4. Furthermore, the types of inks used in liquid injection heads 40D_1, 40D_2, 40D_3, and 40D_4 are different. Specifically, the thickening resistance of the inks used in liquid injection heads 40D_1, 40D_2, 40D_3, and 40D_4 differs. For example, in cases where the color of the inks used in liquid injection heads 40D_1, 40D_2, 40D_3, and 40D_4 is different for each head, four colors of ink—yellow, magenta, turquoise, and black—are used.

[0123] To be more specific, liquid jet heads 40D_1, 40D_2, 40D_3 and 40D_4 are arranged in the direction DM along the outer circumferential surface of the roller 34 in the order of liquid jet head 40D_2, liquid jet head 40D_4, liquid jet head 40D_3 and liquid jet head 40D_1.

[0124] Here, the angles formed by the horizontal plane HP and the jetting surface FN are arranged from smallest to largest as follows: liquid jetting head 40D_1, liquid jetting head 40D_3, liquid jetting head 40D_4, and liquid jetting head 40D_2.

[0125] The support mechanism 50D is a mechanism that supports liquid injection heads 40D_1, 40D_2, 40D_3, and 40D_4. The support mechanism 50D includes support bodies 51D_1, 51D_2, 51D_3, and 51D_4. Support body 51D_1 is a frame and other components that support liquid injection head 40D_1. Support body 51D_2 is a frame and other components that support liquid injection head 40D_2. Support body 51D_3 is a frame and other components that support liquid injection head 40D_3. Support body 51D_4 is a frame and other components that support liquid injection head 40D_4.

[0126] Although not illustrated, the support mechanism 50D includes a drive mechanism for changing the positions of the support bodies 51D_1, 51D_2, 51D_3, and 51D_4. This drive mechanism moves the support bodies 51D_1, 51D_2, 51D_3, and 51D_4 in the X-axis direction while maintaining the spray surface FN at a constant inclination relative to the horizontal plane HP, as described above. This allows switching between a state where the spray surface FN faces the outer periphery of the roller 34 and a state where the spray surface FN faces the covers 61_1 to 61_4 (described later). When the spray surface FN faces the outer periphery of the roller 34, printing on the medium M is performed by the liquid spray heads 40D_1, 40D_2, 40D_3, and 40D_4. With the spray surface FN facing the covers 61_1 to 61_4 (described later), maintenance is performed on the liquid spray heads 40D_1, 40D_2, 40D_3, and 40D_4 by the maintenance mechanism 60D.

[0127] Maintenance mechanism 60D is a mechanism used in the maintenance operation of liquid injection heads 40D_1, 40D_2, 40D_3, and 40D_4. Maintenance mechanism 60D has covers 61_1 to 61_4. Cover 61_1 is an example of a "first cover". Cover 61_2 is an example of a "second cover". Cover 61_3 is an example of a "third cover". Cover 61_4 is an example of a "fourth cover".

[0128] Figure 7 The covers 61_1 to 61_4, indicated by double-dotted lines, are respectively positioned relative to the roller 34 in the X1 or X2 direction. Cover 61_1 is a concave component that covers the spray surface FN of the liquid spray head 40D_1 during the maintenance operation of the maintenance mechanism 60D. Cover 61_2 is a concave component that covers the spray surface FN of the liquid spray head 40D_2 during the maintenance operation of the maintenance mechanism 60D. Cover 61_3 is a concave component that covers the spray surface FN of the liquid spray head 40D_3 during the maintenance operation of the maintenance mechanism 60D. Cover 61_4 is a concave component that covers the spray surface FN of the liquid spray head 40D_4 during the maintenance operation of the maintenance mechanism 60D. Furthermore, covers 61_1 to 61_4 are constructed in the same manner as cover 61 in the first embodiment described above.

[0129] Figure 8 The diagram illustrates an example of a first liquid injection head during capping, namely liquid injection head 40D_1. Figure 9 The diagram illustrates, schematically, an example liquid jet head 40D_2, representing the second liquid jet head during capping. (See diagram for reference.) Figure 8As shown, during capping, the spray surface FN of the liquid injection head 40D_1 is covered by the cap 61_1 at an angle θ1 relative to the horizontal plane HP. In contrast, as... Figure 9 As shown, during capping, the spray surface FN of the liquid injection head 40D_2 is covered by the cap 61_2 at an angle θ2 greater than angle θ1 relative to the horizontal plane HP.

[0130] With respect to these angles θ1 and θ2, the tilt angle of cap 61_2 relative to the horizontal plane HP is greater than that of cap 61_1. Therefore, the absorbent liquid LD within cap 61_2 is more concentrated near the nozzle rows LN_2 compared to the absorbent liquid LD within cap 61_1. In other words, the absorbent liquid LD within cap 61_1 extends over a larger area along the horizontal plane HP, closer to each nozzle row LN, compared to the absorbent liquid LD within cap 61_2. As a result, the distance between each nozzle row LN of the liquid ejector head 40D_2 and the absorbent liquid LD during capping is greater than the distance between the corresponding nozzle rows LN of the liquid ejector head 40D_1 and the absorbent liquid LD during capping. Therefore, assuming that the thickening resistance of the ink used in liquid ejector head 40D_1 and the thickening resistance of the ink used in liquid ejector head 40D_2 are equal, the ink in liquid ejector head 40D_2 is more prone to thickening compared to the ink in liquid ejector head 40D_1. As a result, the difference in ink thickening between these liquid jet heads becomes greater.

[0131] Therefore, the thickening resistance of the ink used in liquid jet head 40D_2 is higher than that of the ink used in liquid jet head 40D_1. That is, the aforementioned first ink is used in liquid jet head 40D_1, while a second ink with higher thickening resistance than the first ink is used in liquid jet head 40D_2. Therefore, the difference in thickening resistance between these heads can be reduced. Following the same principle, the aforementioned third ink is used in liquid jet head 40D_3. Furthermore, the aforementioned fourth ink is used in liquid jet head 40D_4.

[0132] Here, the nozzle N of the liquid jet head 40D_1 is an example of a "first nozzle," and it jets a first ink. The nozzle N of the liquid jet head 40D_2 is an example of a "second nozzle," and it jets a second ink. The nozzle N of the liquid jet head 40D_3 is an example of a "third nozzle," and it jets a third ink. The nozzle N of the liquid jet head 40D_4 is an example of a "fourth nozzle," and it jets a fourth ink.

[0133] Even according to the fifth embodiment described above, the difference in thickening between the first ink and the second ink can be reduced. In this embodiment, as described above, the thickening resistance of the inks used in the liquid jet heads 40D_1 to 40D_4 is different. Specifically, the liquid jetting apparatus 100D includes, for example, a liquid jet head 40D_1 as an example of a "first liquid jet head", a liquid jet head 40D_2 as an example of a "second liquid jet head", a cover 61_1 as an example of a "first cover", and a cover 61_2 as an example of a "second cover". The liquid jet head 40D_1 has a jetting surface FN that includes a plurality of nozzles N for jetting the first ink. The nozzles N of the liquid jet head 40D_1 are an example of a "first nozzle", and the jetting surface FN of the liquid jet head 40D_1 is an example of a "first jetting surface". The liquid jet head 40D_2 has a jetting surface FN that includes a plurality of nozzles N for jetting the second ink. The nozzle N of the liquid injection head 40D_2 is an example of a "second nozzle," and the injection surface FN of the liquid injection head 40D_2 is an example of a "second injection surface." The cover 61_1 is concave in the form of a first posture of the liquid injection head 40D_1 where the angle θ1 between the injection surface FN and the horizontal plane HP is a first angle. The cover 61_2 is concave in the form of a second posture of the liquid injection head 40D_2 where the angle θ2 between the injection surface FN and the horizontal plane HP is a second angle greater than the first angle. Furthermore, both the first ink and the second ink contain a humectant, and the thickening resistance of the second ink is higher than that of the first ink.

[0134] As mentioned above, the larger the angle between the spray surface FN and the horizontal plane HP, the greater the thickening difference of the ink between the nozzles N within the liquid ejector head 40D tends to be. Therefore, by making the thickening resistance of the second ink higher than that of the first ink, the thickening difference of the second ink between the nozzles N of the liquid ejector head 40D_2 can be reduced in a manner close to the thickening difference of the first ink between the nozzles N of the liquid ejector head 40D_1. As a result, the thickening difference of the ink can be reduced between the nozzle rows LN of the liquid ejector head 40D_1 and the nozzle rows LN of the liquid ejector head 40D_2.

[0135] Here, as described in the first embodiment, it is preferable that the effective moisture content of the second ink is lower than that of the first ink. In this case, the thickening resistance of the second ink can be higher than that of the first ink.

[0136] Furthermore, as described in the first embodiment, it is preferable that the hygroscopicity of the second ink is higher than that of the first ink. In this case, the thickening resistance of the second ink can be made higher than that of the first ink.

[0137] 5. Variations

[0138] The methods illustrated above can be modified in a variety of ways. Specific modifications that can be applied to the aforementioned methods are illustrated below. Two or more methods selected from the following examples can be appropriately combined without contradiction.

[0139] 5-1. Variation Example 1

[0140] Figure 10 This is a schematic diagram illustrating the structure of the liquid jetting device 100E according to Modified Example 1. The liquid jetting device 100E is a serial printing device. Figure 10 As shown, the liquid injection device 100E includes: a liquid container 10, a control unit 20E, a conveying mechanism 30E, a moving mechanism 70, a liquid injection head 40E, and a maintenance mechanism 60. Here, the liquid injection head 40E is configured, for example, in the same manner as the liquid injection head 40A of the second embodiment or the liquid injection head 40B of the third embodiment described above.

[0141] Under the control of the control unit 20E, the conveying mechanism 30E conveys the medium M along the W1 or W2 direction of the W axis. Furthermore, similar to the first embodiment, the W axis in this variation is an axis intersecting the horizontal plane HP. Under the control of the control unit 20E, the moving mechanism 70 reciprocates the liquid injection head 40E in the X1 and X2 directions. Figure 10 In the example shown, the moving mechanism 70 has a generally box-shaped support 71, called a carriage, which houses the liquid injection head 40E, and a conveyor belt 72 on which the support 71 is fixed. Similar to the support 51 described above during capping, the support 71 supports the liquid injection head 40E in an inclined posture during both the recording operation and capping. In addition to the liquid injection head 40E, a liquid container 10 is also mounted on the support 71.

[0142] In this embodiment, the maintenance mechanism 60 is positioned in the X1 direction relative to the delivery area of ​​the medium M. During maintenance operations performed by the maintenance mechanism 60, the moving mechanism 70 positions the liquid injection head 40E on the cover 61 of the maintenance mechanism 60.

[0143] Under the control of the control unit 20E, the liquid jet head 40E jets ink supplied from the liquid container 10 toward the medium M. Although not shown in the figure, the jetting direction is the aforementioned V2 direction. By performing this jetting in parallel with the transport of the medium M by the transport mechanism 30E and the reciprocating movement of the liquid jet head 40E by the moving mechanism 70, a predetermined image composed of ink is formed on the surface of the medium M.

[0144] Even with the above variation 1, the difference in thickening between the first ink and the second ink can be reduced.

[0145] 5-2. Variation Example 2

[0146] Although the first embodiment described above illustrates the case where nozzle array LN_1 is understood as the "first nozzle array" and nozzle array LN_2 as the "second nozzle array," the first and second nozzle arrays are not limited to this example. Specifically, any one of the nozzle arrays LN_1, LN_3, and LN_4 can be understood as the "first nozzle array." In this case, any nozzle array LN that is located vertically below the first nozzle array LN in the tilted position can be understood as the "second nozzle array." Thus, the "second nozzle array" is not limited to nozzle array LN_2, but can also be nozzle array LN_3 or nozzle array LN_4.

[0147] Furthermore, the configuration, quantity, or length of the nozzle array can be any arrangement that includes a first nozzle array and a second nozzle array with different positions in the vertical direction, and is not limited to the aforementioned arrangements.

[0148] Figure 11 Here is a top view of the liquid injection head 40F in Modified Example 2. Figure 11 The diagram schematically illustrates a liquid jet head 40F viewed from above when the jet surface FN is tilted, i.e., under pressure. The liquid jet head 40F is used, for example, in a serial printing apparatus as shown in Variation 1, and has nozzle rows LNa, LNb, LNc, and LNd extending in the direction along the W-axis. These nozzle rows are each composed of nozzles N arranged in the direction along the X-axis.

[0149] Nozzle arrays LNa, LNb, and LNc are arranged in this order along the same straight line in the W2 direction. Therefore, the vertical position Pa of nozzle array LNa is higher than the vertical position Pb of nozzle array LNb and higher than the vertical position Pc of nozzle array LNc. Furthermore, the vertical position Pb of nozzle array LNb is higher than the vertical position Pc of nozzle array LNc. Further, the vertical position Pd of nozzle array LNd is equal to the vertical position Pc of nozzle array LNc.

[0150] Here, nozzle array LNa or nozzle array LNb is designated as the "first nozzle array" and ejects the first ink. If nozzle array LNa is understood as the "first nozzle array," then any one of nozzle arrays LNb, LNc, or LNd is designated as the "second nozzle array" and ejects the second ink. If either nozzle array LNc or ​​LNd is considered as the "second nozzle array," then nozzle array LNb is designated as the "third nozzle array" and ejects the third ink. Conversely, if nozzle array LNb is considered as the "first nozzle array," then any one of nozzle arrays LNc or ​​LNd is designated as the "second nozzle array" and ejects the second ink.

[0151] 5-3. Variation Example 3

[0152] Although in the first embodiment described above, the orientation of the liquid jet head 40 during the recording operation is different from that during the maintenance operation, the orientations of the liquid jet head 40 during the recording operation and the maintenance operation can also be the same. In this case, during the recording operation, the spray surface FN is also tilted relative to the horizontal plane HP. Furthermore, in this case, for example, the maintenance mechanism 60 can be appropriately configured to perform maintenance on the liquid jet head 40 performed by the maintenance mechanism 60.

[0153] 5-4. Variation Example 4

[0154] Although in the first embodiment described above, the liquid spray head 40 is set to an inclined position during the maintenance operation, the liquid spray head 40 may not be in an inclined position during the maintenance operation. For example, the liquid spray head 40 may only be set to an inclined position when recording the operation.

[0155] 5-5. Variation Example 5

[0156] The liquid jetting apparatus 100 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 forming color filters in a liquid crystal display device. Furthermore, a liquid jetting apparatus that jets a solution of conductive material can be used as a manufacturing apparatus for forming wiring or electrodes on a wiring board.

[0157] Example

[0158] Specific embodiments of the present invention will be described below. However, the present invention is not limited to the following embodiments.

[0159] A: Ink production

[0160] A-1: Production of Black Ink

[0161] A-1a: Preparation of Dispersion

[0162] First, prepare anionic polymer P-1 [styrene / butyl acrylate / acrylic acid copolymer (polymerization ratio (mass ratio) = 30 / 40 / 30), acid value 202, weight average molecular weight 6500]. Neutralize it in potassium hydroxide aqueous solution and dilute it with deionized water to prepare a homogeneous polymer aqueous solution with a mass percentage of 10%.

[0163] The prepared polymer solution (600g), carbon black (100g), and deionized water (300g) were mixed and mechanically stirred for a predetermined time. The mixture was then centrifuged to remove non-dispersible matter containing coarse particles, resulting in a black dispersion. The pigment concentration of the obtained black dispersion was 10% by mass.

[0164] A-1b: Ink Preparation

[0165] Other ingredients were added to the obtained black dispersion in the following proportions and thoroughly mixed and stirred. The mixture was then pressure filtered using a microfilter (manufactured by Fujifilm) with a pore size of 2.5 μm to obtain a black ink with a pigment concentration of 2.5% by mass.

[0166] Black dispersion: 25 parts by weight

[0167] Zonier FSO-100 (manufactured by DuPont): 0.05 parts by weight

[0168] Glycerin: 8 parts by weight

[0169] 2-Pyrrolidone: 6 parts by weight

[0170] Ethylene glycol EO additive (manufactured by Kawakami Fine Chemicals Co., Ltd.): 0.5 parts by weight

[0171] Trimethylolpropane: 3 parts by weight

[0172] Ion-exchanged water: Remaining portion (= 57.45 parts by mass)

[0173] A-2: Production of Blue-Green Ink

[0174] A-2a: Preparation of Dispersion

[0175] First, using benzyl acrylate and methacrylic acid as raw materials, an AB-type block polymer with an acid value of 250 and a number-average molecular weight of 3000 is prepared using conventional methods. The polymer is neutralized in an aqueous solution of potassium hydroxide and diluted with deionized water to produce a homogeneous polymer aqueous solution with a mass percentage of 50%.

[0176] The prepared polymer solution (200g), CI pigment blue 15:3 (100g), and deionized water (700g) were mixed and mechanically stirred for a predetermined time. Then, the mixture was centrifuged to remove non-dispersible matter containing large particles, resulting in a blue-green dispersion. The pigment concentration of the obtained blue-green dispersion was 10% by mass.

[0177] A-2b: Ink Preparation

[0178] Other components were added to the obtained blue-green dispersion in the following proportions and thoroughly mixed and stirred. The mixture was then pressure filtered using a microfilter (manufactured by Fujifilm) with a pore size of 2.5 μm to obtain a blue-green ink with a pigment concentration of 2.5% by mass.

[0179] Blue-green dispersion: 25 parts by weight

[0180] Zonier FSO-100 (manufactured by DuPont): 0.05 parts by weight

[0181] Glycerin: 15 parts by weight

[0182] 2-Pyrrolidone: 5 parts by weight

[0183] Ethylene glycol EO additive (manufactured by Kawakami Fine Chemicals Co., Ltd.): 0.5 parts by weight

[0184] Triethanolamine: 1 part by weight

[0185] Ion-exchanged water: Remaining portion (= 53.45 parts by mass)

[0186] A-3: Production of Magenta Ink

[0187] A-3a: Preparation of Dispersion

[0188] First, using benzyl acrylate and methacrylic acid as raw materials, an AB-type block polymer with an acid value of 300 and a number-average molecular weight of 2500 is prepared using conventional methods. The polymer is neutralized in an aqueous solution of potassium hydroxide and diluted with deionized water to produce a homogeneous polymer aqueous solution with a mass percentage of 50%.

[0189] The prepared polymer solution (100g), CI Pigment Red 122 (100g), and ion-exchanged water (800g) were mixed and mechanically stirred for a predetermined time. Then, the mixture was centrifuged to remove non-dispersible matter containing large particles, thus obtaining a magenta dispersion. The pigment concentration of the obtained magenta dispersion was 10% by mass.

[0190] A-3b: Ink Preparation

[0191] Other ingredients were added to the obtained magenta dispersion in the following proportions and mixed thoroughly. The mixture was then pressure filtered using a microfilter (manufactured by Fujifilm) with a pore size of 2.5 μm to obtain a magenta ink with a pigment concentration of 2.5% by mass.

[0192] Magenta dispersion: 25 parts by weight

[0193] Zonier FSO-100 (manufactured by DuPont): 0.05 parts by weight

[0194] Glycerin: 12 parts by weight

[0195] 2-Pyrrolidone: 5 parts by weight

[0196] Ethylene glycol EO additive (manufactured by Kawakami Fine Chemicals Co., Ltd.): 0.5 parts by weight

[0197] Triethanolamine: 2 parts by weight

[0198] Trimethylolpropane: 1 part by weight

[0199] Ion-exchanged water: Remaining portion (= 54.45 parts by mass)

[0200] A-4: Production of Yellow Ink

[0201] A-4a: Preparation of Dispersion

[0202] First, the same anionic polymer P-1 used in the production of black ink is neutralized in an aqueous solution of potassium hydroxide and diluted with ion-exchanged water to produce a homogeneous polymer aqueous solution of 10% by mass.

[0203] The prepared polymer solution (300g), CI Pigment Yellow 74 (100g), and ion-exchanged water (600g) were mixed and mechanically stirred for a predetermined time. Then, centrifugation was performed to remove non-dispersible matter containing coarse particles, thereby obtaining a yellow dispersion. The resulting yellow dispersion had a pigment concentration of 10% by mass.

[0204] A-4b: Ink Preparation

[0205] Other ingredients were added to the obtained yellow dispersion in the following proportions and mixed thoroughly. The mixture was then pressure filtered using a microfilter (manufactured by Fujifilm) with a pore size of 1.0 μm to obtain a yellow ink with a pigment concentration of 2.5% by mass.

[0206] Yellow dispersion: 25 parts by weight

[0207] Zonier FSO-100 (manufactured by DuPont): 0.25 parts by weight

[0208] Glycerin: 10 parts by weight

[0209] 2-Pyrrolidone: 1 part by weight

[0210] Ethylene glycol EO additive (manufactured by Kawakami Fine Chemicals Co., Ltd.): 1 part by weight

[0211] Triethanolamine: 7 parts by weight

[0212] Sodium carbonate: 0.5 parts by weight

[0213] Ion-exchanged water: Remaining portion (= 52.75 parts by mass)

[0214] Using the above method, black ink, blue-green ink, magenta ink, and yellow ink were obtained. The components of these inks are summarized in Table 1. Additionally, Table 1 also shows the effective water content and hygroscopicity of each ink.

[0215] Table 1

[0216]

[0217] B: Evaluation

[0218] The evaluation was conducted on the application of black ink, blue-green ink, magenta ink, and yellow ink obtained using the method described above to the aforementioned... Figure 2 The thickening of ink occurs in a liquid ejector head as shown. Here, the liquid ejector head is placed in a situation such as... Figure 3The ink was sealed with a cap as shown and left for one week. Afterward, ink was sprayed from the nozzle onto the medium. The thickening of the ink was evaluated by observing the deviation in the spray position of the ink on the medium. When the ink near the nozzle thickened, the ink's responsiveness decreased, resulting in a slower ink ejection speed, meaning a slower arrival time of the ink on the medium. Therefore, it can be said that the greater the deviation in the spray position, the greater the thickening. Alternatively, the thickening of the ink can be evaluated by observing the area near the nozzle using a high-speed camera. Furthermore, the angle θ between the horizontal plane and the spray surface was set to 45°, and glycerin was added as a desiccant in the lower part of the cap.

[0219] When black ink is used as the first ink, blue-green ink as the second ink, yellow ink as the third ink, and magenta ink as the fourth ink, it was confirmed that the difference in ink thickening between nozzles is smaller compared to the cases where black ink is used as the second ink, blue-green ink as the first ink, yellow ink as the fourth ink, and magenta ink as the third ink.

[0220] Symbol Explanation

[0221] 10…Liquid container; 20…Control unit; 20E…Control unit; 30…Conveying mechanism; 30D…Conveying mechanism; 30E…Conveying mechanism; 31…Supply mechanism; 31a…First supply roller; 31b…Second supply roller; 32…Discharge mechanism; 32a…First discharge roller; 32b…Second discharge roller; 33…Belt mechanism; 33a…First conveyor roller; 33b…Second conveyor roller; 33c…Conveyor belt; 34…Drum; 40…Liquid spray head; 40A…Liquid spray head; 40B…Liquid spray head; 40C…Liquid spray head; 40D…Liquid spray head; 40D_1…Liquid spray head (first liquid spray head) ; 40D_2… Liquid injection head (second liquid injection head); 40D_3… Liquid injection head (third liquid injection head); 40D_4… Liquid injection head (fourth liquid injection head); 40E… Liquid injection head; 40F… Liquid injection head; 41… Head chip; 41A… Head chip; 41B… Head chip; 41_1… Head chip; 41_2… Head chip; 41_3… Head chip; 41_4… Head chip; 41a… Head chip; 41b… Head chip; 41c… Head chip; 41d… Head chip; 41e… Head chip; 41f… Head chip; 41g… Head chip; 41h… Head chip; 42… Head; 43… Head; 44…head; 50…support mechanism; 50D…support mechanism; 51…support body; 51D_1…support body; 51D_2…support body; 51D_3…support body; 51D_4…support body; 60…maintenance mechanism; 60D…maintenance mechanism; 61…cover; 61_1…cover; 61_2…cover; 61_3…cover; 61_4…cover; 61a…bottom wall; 61b…side wall; 61c…recess; 62…suction pump; 70…moving mechanism; 71…support body; 72…conveyor belt; 100…liquid jet device; 100D…liquid jet device; 100E…liquid jet device; 33a…first conveyor roller; 33b …Second conveyor roller; AX…Central shaft; C…Pressure chamber; DM…Direction; E…Drive element; FN…Spray surface; HP…Horizontal plane; LD…Absorbent liquid; LN…Nozzle array; LN_1…Nozzle array (first nozzle array); LN_2…Nozzle array (second nozzle array); LN_3…Nozzle array (third nozzle array); LN_4…Nozzle array (fourth nozzle array); LNa…Nozzle array; LNb…Nozzle array; LNc…Nozzle array; LNd…Nozzle array; M…Media; N…Nozzle; N_1…Nozzle; N_2…Nozzle; N_3…Nozzle; N4…Nozzle; θ…Angle; θ0…Angle; θ1…Angle; θ2…Angle.

Claims

1. A liquid injection device, characterized in that, have: A liquid jetting head having a jetting surface, the jetting surface including a first nozzle array for jetting a first ink and a second nozzle array for jetting a second ink; A support body capable of supporting the liquid jet head in an inclined posture with the jet surface tilted relative to the horizontal plane; The cover, which is concave, covers the spray surface while the support body supports the liquid injection head in the tilted position. One or both of the first ink and the second ink contain a humectant. With the support body supporting the liquid injection head in the tilted position, the first nozzle array is located vertically above the second nozzle array. The thickening resistance of the second ink is higher than that of the first ink. The cover is used to press the spray surface during maintenance operations, including suction cleaning, pressurized cleaning, and rinsing.

2. The liquid injection device as claimed in claim 1, wherein, The effective moisture content of the second ink is less than that of the first ink.

3. The liquid injection device as described in claim 2, wherein, The effective moisture content of the first ink is more than twice that of the effective moisture content of the second ink.

4. The liquid injection device according to any one of claims 1 to 3, wherein, The second ink has a higher hygroscopicity than the first ink.

5. The liquid injection device as claimed in claim 1, wherein, The support body can change the angle between the spray surface and the horizontal plane. The angle between the jet surface and the horizontal plane during the recording action on the medium is smaller than the angle between the jet surface and the horizontal plane during the tilted posture.

6. The liquid injection device as claimed in claim 1 or 5, wherein, The cover has a bottom wall and a side wall extending across the entire area from the outer periphery of the bottom wall, forming a closed space surrounded by the bottom wall, the side wall and the spray surface, and openings within the closed space for a plurality of nozzles constituting the first nozzle array and a plurality of nozzles constituting the second nozzle array.

7. The liquid injection device as claimed in claim 1, wherein, The spraying surface also has a third row of nozzles for spraying the third ink. With the support body supporting the liquid injection head in the tilted position, the third nozzle array is located vertically between the first nozzle array and the second nozzle array. The thickening resistance of the third ink is higher than that of the first ink and lower than that of the second ink.

8. The liquid injection device as claimed in claim 7, wherein, The spraying surface also has a fourth row of nozzles for spraying a fourth ink. With the support body supporting the liquid injection head in the tilted position, the fourth nozzle array is located vertically between the second and third nozzle arrays. The thickening resistance of the fourth ink is lower than that of the second ink but higher than that of the third ink.

9. The liquid injection device as claimed in claim 1, wherein, When the support body supports the liquid jet head in the tilted posture, and the direction along the intersection of the jet surface and the horizontal plane is defined as the first direction, and the direction along the jet surface that is orthogonal to the first direction is defined as the second direction, the respective arrangement directions of the first nozzle array and the second nozzle array intersect with the second direction.

10. The liquid injection device as claimed in claim 1, wherein, With the support body supporting the liquid injection head in the tilted posture, when viewed along the direction of the intersection of the injection surface and the horizontal plane, a portion of one of the first nozzle array and the second nozzle array repeats at least a portion of the other. The lowermost nozzle in the vertical direction among the plurality of nozzles in the first nozzle column is located above the lowermost nozzle in the vertical direction among the plurality of nozzles in the second nozzle column.

11. The liquid injection device as claimed in claim 1, wherein, During the rinsing action, the amount of the first ink ejected from the first nozzle array is equal to the amount of the second ink ejected from the second nozzle array.

12. A liquid injection device, characterized in that, have: A first liquid ejector head has a first ejection surface comprising a plurality of first nozzles for ejecting a first ink; The second liquid jet head has a second jetting surface including a plurality of second nozzles for jetting the second ink; The first cover is concave and covers the first spray surface in a first posture where the angle between the first spray surface and the horizontal plane is a first angle. The second cover is concave and covers the second spray surface in a second orientation where the angle between the second spray surface and the horizontal plane is a second angle greater than the first angle. Both the first ink and the second ink contain a humectant. The thickening resistance of the second ink is higher than that of the first ink. During maintenance procedures including suction cleaning, pressurized cleaning, and rinsing, the first cover presses down on the first spray surface. The second cover is used to press the second spray surface during maintenance operations, including suction cleaning, pressurized cleaning, and rinsing.

13. The liquid injection device as claimed in claim 12, wherein, The effective moisture content of the second ink is less than that of the first ink.

14. The liquid injection device as claimed in claim 12 or 13, wherein, The second ink has a higher hygroscopicity than the first ink.

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