Image formation method

Abstract

To provide an image formation method that achieves both quick-drying of ink and suppression of imbibition of a resin part inside a head.SOLUTION: The present invention pertains to a method of forming an image by discharging ink from an inkjet head. The inkjet head includes an ink flow path, and a resin part at least partially exposed to the ink flow path. The resin part includes a cured product of a composition containing an episulfide resin and a polythiol compound. The ink contains C1-C4 alcohol by an amount of 60 mass% or more and 95 mass% or less with respect to the total mass of the ink.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to an image forming method. [Background technology]

[0002] The inkjet method is widely used because it can form images on various substrates, including paper and film. However, when forming images on non-absorbent substrates such as film, if the applied ink does not dry sufficiently, the image may fade or transfer when it comes into contact with other substrates, resulting in a decrease in image quality. Therefore, there is a demand for fast-drying ink.

[0003] Quick-drying inks use highly volatile ketones or alcohols as solvents. For example, Patent Document 1 describes an ink whose quick-drying properties are enhanced by the use of methyl ethyl ketone. Patent Document 2 describes an ink whose quick-drying properties are enhanced by the use of a low-carbon alcohol. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-113258 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-138201 Summary of the Invention [Problem to be solved by the invention]

[0005] As described in Patent Document 2, inks that use alcohol to improve quick-drying properties are known. However, alcohol has a high permeability to resin. Therefore, when attempting to form images using such inks by inkjet printing, the ink permeates the resin inside the inkjet head, causing the resin to swell. For example, swelling of the adhesive can cause deformation of the head or peeling due to localized stress concentration, leading to problems such as missing nozzles.

[0006] The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming method that achieves both quick drying of ink and suppression of swelling of the resin portion inside the head. [Means for solving the problem]

[0007] One aspect of the present invention for solving the above problems relates to the following image forming methods [1] to

[13] . [1] A method for forming an image by ejecting ink from an inkjet head, the inkjet head has an ink flow path and a resin portion at least partially exposed to the ink flow path; the resin portion includes a cured product of a composition including an episulfide resin and a polythiol compound, the ink contains an alcohol having 1 to 4 carbon atoms in an amount of 60% by mass to 95% by mass relative to the total mass of the ink; Image forming method. [2] The ink contains ethanol in an amount of 30% by mass or more based on the total mass of the ink. [1] The image forming method according to [1]. [3] The resin portion is a cured product of a composition further containing a curing catalyst. The image forming method according to [1] or [2]. [4] The curing catalyst comprises an amine or an imidazole. [3] The image forming method according to [3]. [5] The cured product is immersed in 100% ethanol at 60°C for two weeks, and then the sample temperature is raised from 30°C to 100°C at a rate of 7°C / min. After that, TGA measurement is performed by holding the sample for one hour. The impregnation rate calculated from the mass using the following formula (1) is less than 4.0%. The image forming method according to claim 1. Impregnation rate (%) = (mass before TGA heating - mass after TGA heating) / (mass before TGA heating) × 100 (1) [6] The polythiol compound is a compound having four or more thiol groups. The image forming method according to any one of [1] to [5]. [7] The resin portion is a joining portion that joins the vibration plate and the pressure chamber forming substrate. The image forming method according to any one of [1] to [6]. [8] The resin portion has a thickness of 0.1 μm or more and 2.5 μm or less. [7] The image forming method according to [7]. [9] The resin portion is a joining portion that joins the nozzle plate and the pressure chamber forming substrate. The image forming method according to any one of [1] to [8].

[10] The resin portion has a thickness of 0.5 μm or more and 4.0 μm or less. [9] The image forming method according to [9].

[11] The inkjet head circulates the ink for each nozzle that ejects the ink. The image forming method according to any one of [1] to

[10] .

[12] When the ink is not being ejected, the inkjet head causes the ink to flow by a vibration waveform. The image forming method according to any one of [1] to

[11] .

[13] Forming an image on a recording medium transported by roll-to-roll. The image forming method according to any one of [1] to

[12] . [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an image forming method that achieves both quick drying of ink and suppression of swelling of the resin portion inside the head. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of an inkjet printer equipped with an inkjet head according to an embodiment. [Figure 2] FIG. 2 is a block diagram showing the main components of the control system of the inkjet printer. [Figure 3] FIG. 3 is a diagram showing a schematic arrangement of inkjet heads in a head unit of an inkjet printer. [Figure 4] FIG. 4 is a perspective view showing the appearance of the inkjet head. [Figure 5A] FIG. 5A is a diagram schematically illustrating a configuration of a main part of a cross section along the short-side direction of a head chip in an inkjet head. [Figure 5B] FIG. 5B is a diagram schematically illustrating the configuration of a main part of a cross section along the longitudinal direction of a head chip in an inkjet head. [Figure 6] FIG. 6 is a diagram showing a cross-sectional configuration of a pressure chamber forming plate in an inkjet head. [Figure 7] FIG. 7 is a diagram showing a cross-sectional view of a main part of the inkjet head according to the embodiment, in the vicinity of a pressure chamber. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0011] The present embodiment relates to a method for forming an image using an inkjet head that uses a specific cured material for the resin part and ink with a high alcohol concentration. The following describes an inkjet printer having the inkjet head and the ink.

[0012] [Inkjet printer 1] Fig. 1 is a diagram showing the schematic configuration of an inkjet printer used to form an image in this embodiment, and Fig. 2 is a block diagram showing the main parts of the control system of the inkjet printer. The inkjet printer described below is an example of an image forming apparatus.

[0013] As shown in Figures 1 and 2, the inkjet printer 1 includes a conveying unit 10, a supply unit 20, a discharge unit 30, an ink supply unit 40, a drawing unit 50, a drying unit 95, a reading unit 60, an operation display unit 70, an input / output interface 80, and a control unit 90.

[0014] The transport unit 10 has multiple components related to transport, such as a transport belt 11, a drive roller 12, and a driven roller 13. The transport unit 10 transports the recording medium M by the transport operation of the multiple components, such as the transport belt 11. Specifically, in the transport unit 10, the transport belt 11 is stretched across the drive roller 12 and the driven roller 13, and is driven by driving the drive roller 12 to rotate. As a result, the recording medium M supplied from the supply unit 20 is transported to the imaging unit 50 while placed on the transport surface 11a of the transport belt 11, and after imaging (also referred to as image formation or printing) in the imaging unit 50, is transported to the discharge unit 30. In this way, the inkjet printer 1 forms images in a roll-to-roll manner.

[0015] The recording medium M can be any of a variety of media capable of fixing the ink ejected from the inkjet head 55. The recording medium M is, for example, a roll of resin (film). Note that the recording medium M is not limited to film, but may also be sheet-like paper or cloth (woven fabric). The recording medium M is also not limited to a roll-like medium, but may also be sheet-like paper, cloth, resin, or other media. An example of a resin recording medium M is PET film used for packaging food. Other examples of recording media M that can be used as a drawing target include the metal body of an automobile, building materials (exterior walls, roofing materials, tiles, etc.), and cans (metal cans for storing food, beverages, etc.).

[0016] 1 illustrates, as an example of an image forming apparatus, a conveying unit 10 that conveys a recording medium M with a conveying belt 11. However, the conveying unit 10 is not limited to the conveying belt 11, and may be configured to convey the recording medium M with a drum or roller.

[0017] The supply unit 20 has a storage unit 21 that stores the recording medium M stored in a roll, and an unwinding roller 22 that unwinds and supplies the recording medium M from the storage unit 21 to the transport unit 10.

[0018] The discharge section 30 has a storage section 31 that stores the recording medium M in a roll form, and a take-up roller 32 that transports the recording medium M transported from the transport section 10 to the storage section 31.

[0019] The unwinding roller 22 and the winding roller 32 each have, for example, a plurality of rollers, and convey the recording medium M by rotating the rollers.

[0020] The configurations of the transport unit 10, the supply unit 20, and the discharge unit 30 can be modified in various ways depending on the type of recording medium M to be imaged.

[0021] The ink supply unit 40 is a device that supplies ink to a first sub-tank 52a of the drawing unit 50, which will be described later. The ink supply unit 40 has a main tank 41 and components related to ink supply (e.g., a pump, a valve, etc.) not shown. The main tank 41 stores ink at room temperature to be supplied to the first sub-tank 52a. The ink supply unit 40 uses a pump or the like (not shown) to supply ink from the main tank 41 to the first sub-tank 52a via a flow path 42.

[0022] The drawing unit 50 has a carriage 51, a first sub-tank 52a, a second sub-tank 52b, flow paths 53a, 53b, and 53c, a head driving unit 54, an inkjet head 55, etc. (See FIGS. 1 and 2.) In this embodiment, the drawing unit 50 applies ink containing 60% by mass to 95% by mass of alcohol having 1 to 4 carbon atoms (high alcohol concentration ink) to the recording medium M to form an image.

[0023] 1, for simplicity, ink supply units 40 and drawing units 50 for one color are shown, but the ink supply units 40 and drawing units 50 are arranged according to the number of colors used. For example, when four colors, yellow (Y), magenta (M), cyan (C), and black (K), are used, ink supply units 40 and drawing units 50 for four colors are arranged, and the drawing units 50 are arranged so as to be lined up at predetermined intervals along the transport direction T.

[0024] Furthermore, a plurality of second sub-tanks 52b and heads 55 are connected downstream of the first sub-tank 52a, but for the sake of simplicity, only one of each is shown in FIG.

[0025] The carriage 51 is a housing that holds inside it the first sub-tank 52a, the second sub-tank 52b, the flow paths 53a, 53b, and 53c, the head drive unit 54, the head 55, and other devices and components required for image formation. Although not shown, the carriage 51 may also have an ink heating unit that heats and maintains the ink inside the carriage 51.

[0026] The first sub-tank 52a is connected to the downstream side of the main tank 41. The first sub-tank 52a stores ink supplied from the main tank 41 inside the carriage 51. The ink in the sub-tank 52 is supplied to the second sub-tank 52b via a flow path 53a using a pump or the like (not shown) inside the carriage 51.

[0027] A plurality of second sub-tanks 52b are connected downstream of the first sub-tank 52a. The second sub-tank 52b stores ink supplied from the first sub-tank 52a inside the carriage 51. The ink in the second sub-tank 52b is supplied to a manifold 56 of the head 55 (described later) via a flow path 53b using a pump or the like (not shown) inside the carriage 51. Furthermore, a portion of the ink supplied to the manifold 56 is returned (recovered) to the second sub-tank 52b via a flow path 53c, and can be re-supplied to the manifold 56. In other words, the ink circulates between the second sub-tank 52b and the manifold 56 via the flow paths 53b and 53c.

[0028] Based on the control of a control unit 90 (described later), the head driving unit 54 outputs a driving voltage corresponding to the image data of the image to be formed to a piezoelectric element 58 of a head 55 (described later). The driving voltage from the head driving unit 54 drives the piezoelectric element 58, causing it to eject an amount of ink corresponding to the image data from a nozzle 59 of the head 55 (described later). Note that the head driving unit 54 may output a driving voltage to the piezoelectric element 58 corresponding to a fluctuating waveform for causing the ink in the nozzle to flow slightly and stabilize it when ink is not being ejected.

[0029] The oscillation waveform is a waveform that contracts or expands the volume of the pressure chamber 57 within a range that generates only a pressure wave without causing ejection. By using the oscillation waveform to oscillate the ink interface near the nozzle 59, clogging (decapping) caused by the ink drying and increasing viscosity can be suppressed.

[0030] A plurality of heads 55 are connected to the downstream sides of the plurality of second sub-tanks 52b, respectively. That is, a plurality of second sub-tanks 52b and heads 55 are connected to the downstream sides of the first sub-tanks 52a.

[0031] The head 55 has a manifold 56, pressure chambers 57, piezoelectric elements 58, nozzles 59, a common supply flow path 112a, individual supply flow paths 112b, a vertical supply flow path 112c, a common discharge flow path 112d, individual discharge flow paths 112e, and a vertical discharge flow path 112f (see FIGS. 5A, 5B, and 6). The head 55 has a plurality of nozzles 59, and the pressure chambers 57 and piezoelectric elements 58 are provided in accordance with the number of nozzles 59.

[0032] The manifold 56 communicates with a plurality of pressure chambers 57 via each supply flow path, and ink supplied to the manifold 56 is supplied to the pressure chambers 57. The pressure chambers 57 are chambers that have an internal space in which ink ejected from nozzles 59 can be temporarily stored, either partially or entirely. A piezoelectric element 58 is disposed above the pressure chambers 57. One end of the nozzles 59 communicates with the pressure chambers 57, and the other end is an open end.

[0033] A drive voltage is applied to the piezoelectric element 58 from the head drive unit 54. When the drive voltage from the head drive unit 54 is applied to the piezoelectric element 58, the piezoelectric element 58 deforms in accordance with the applied drive voltage, which deforms the pressure chamber 57. The deformation of the pressure chamber 57 causes a pressure change in the ink in the pressure chamber 57 that is supplied to the nozzle 59.

[0034] Therefore, when a drive voltage from the head drive unit 54 is applied to the piezoelectric element 58, the piezoelectric element 58 and the pressure chamber 57 are deformed, causing a pressure change in the ink inside the pressure chamber 57, and as a result, the ink inside the pressure chamber 57 is ejected from the nozzle 59. In this way, an image can be formed on the recording medium M by ejecting ink from the nozzle 59.

[0035] In the carriage 51, the heads 55 may be configured to use a single-pass (one-pass) method in which an image is formed in one scan, or a scan (multi-pass) method in which an image is formed in multiple scans. In the case of a single-pass method, the carriage 51 is provided with heads 55 in the width direction of the recording medium M (a direction perpendicular to the conveyance direction T of the recording medium M), the number of which corresponds to the image formation width (see FIG. 3). As shown in FIG. 3, the multiple heads 55 are arranged in one or multiple rows with their longitudinal directions aligned with the width direction of the recording medium M, and in each head 55, the multiple nozzles 59 are arranged linearly or in a grid pattern along the longitudinal direction of the head 55.

[0036] The drying unit 95 is disposed downstream of the imaging unit 50 in the transport direction T of the recording medium M, and heats and dries the ink applied to the recording medium M. The drying unit 95 is connected to the control unit 90 (see FIG. 2) and is controlled by the control unit 90.

[0037] For example, the drying unit 95 has an infrared heater or the like, and when power is supplied to the infrared heater based on a control signal supplied from the control unit 90, the infrared heater generates heat and dries the ink. The heating conditions for the drying unit 95 need only be conditions that dry the high-alcohol concentration ink. Furthermore, if the ink has sufficient drying properties, the inkjet printer 1 does not need to have the drying unit 95.

[0038] The reading unit 60 is disposed downstream of the drawing unit 50 and the drying unit 95 in the transport direction T of the recording medium M, and reads an image (for example, a predetermined pattern image) formed on the recording medium M transported by the transport belt 11. The reading unit 60 outputs the reading result of the predetermined pattern image to the control unit 90. Based on the reading result, the control unit 90 changes the image formation conditions, for example, the image formation position and the driving conditions of the head 55.

[0039] Although not shown, the inkjet printer 1 also includes a maintenance unit that performs maintenance such as cleaning of the head 55.

[0040] The operation display unit 70 is, for example, a flat panel display such as a liquid crystal display with a touch panel or an organic EL (Electro Luminescence) display. The operation display unit 70 displays an operation menu for the user, information related to image data, various states of the inkjet printer 1, etc. The operation display unit 70 also has a plurality of keys and accepts various input operations from the user.

[0041] The input / output interface 80 mediates the transmission and reception of data between the external device 99 and the control unit 90. The input / output interface 80 is configured, for example, by any one of various serial interfaces, various parallel interfaces, or a combination of these.

[0042] The external device 99 is, for example, a personal computer or a facsimile machine, and supplies print jobs, image data, and the like to the control unit 90 via the input / output interface 80 .

[0043] The control unit 90 includes a CPU (Central Processing Unit) 91, a RAM (Random Access Memory) 92, a ROM (Read Only Memory) 93, a storage unit 94, and the like.

[0044] The CPU 91 reads out various control programs and setting data stored in the ROM 93, stores them in the RAM 92, and executes the programs to perform various arithmetic processing. For example, the control unit 90 generates a drive signal for an image to be formed based on image data received from the input / output interface 80, and outputs the drive signal to the head 55.

[0045] The RAM 92 provides a working memory space for the CPU 91 and stores temporary data. The RAM 92 may include a non-volatile memory.

[0046] The ROM 93 stores various control programs and setting data executed by the CPU 91. Note that, instead of the ROM 93, a rewritable non-volatile memory such as an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory may be used.

[0047] The storage unit 94 stores print jobs and image data related to the print jobs input from the external device 99 via the input / output interface 80. As the storage unit 94, for example, a nonvolatile semiconductor memory (so-called flash memory) or an HDD (Hard Disk Drive) is used, and a DRAM (Dynamic Random Access Memory) or the like may also be used in combination.

[0048] The control unit 90 is connected to the transport unit 10, supply unit 20, discharge unit 30, ink supply unit 40, drawing unit 50, reading unit 60, operation and display unit 70, input / output interface 80, drying unit 95, etc. The control unit 90 controls the overall operation of the inkjet printer 1. The transport unit 10, supply unit 20, discharge unit 30, ink supply unit 40, drawing unit 50, reading unit 60, operation and display unit 70, input / output interface 80, drying unit 95, etc. are controlled by the control unit 90 to execute predetermined processes.

[0049] The inkjet printer 1 having the above configuration supplies the recording medium M from the supply unit 20 to the conveying unit 10 under the control of the control unit 90, draws on the recording medium M conveyed to the conveying unit 10 using the drawing unit 50, and conveys the recording medium M with the image formed thereon to the discharge unit 30.

[0050] [Head (inkjet head) 55] Next, the configuration of the inkjet head (head 55) according to this embodiment will be described. The configuration described here is the configuration of a single head 55. Note that all heads 55 in the inkjet printer 1 may have the same configuration, or the inkjet printer 1 may include heads 55 with configurations different from those described below.

[0051] FIG. 4 is a perspective view showing the appearance of the head 55. As shown in FIG.

[0052] The head 55 includes a housing 101 and an exterior member 102 that fits into the housing 101 at its bottom, with the main components housed inside the housing 101 and the exterior member 102. The exterior member 102 is provided with an inlet 103a through which ink is supplied from the outside, and outlets 103b and 103c through which ink is discharged to the outside. A manifold 56 connected to the inlet 103a is also provided inside the exterior member 102. The exterior member 102 is also provided with a plurality of mounting holes 104 for mounting the inkjet head 55 to the base of the carriage 51.

[0053] 5A and 5B are diagrams showing the configuration of the main parts of the head chip in the head 55. Fig. 5A is a diagram showing the configuration of the main parts in a cross section along the short side of the head chip, and Fig. 5B is a diagram showing the configuration of the main parts in a cross section along the long side of the head chip. Fig. 6 is a diagram showing the cross-sectional configuration of a pressure chamber forming plate 112 in the head 55.

[0054] The components housed inside housing 101 and exterior member 102 of head 55 include a head chip 110. As shown in Figures 5A and 5B, head chip 110 is configured by laminating and bonding multiple substrates (a nozzle plate 111, a pressure chamber forming plate 112 (pressure chamber forming substrate), a drive plate 113, and a housing part 114, which are laminated in this order).

[0055] The nozzle plate 111 has a plurality of nozzles 59 (ejection holes) arranged in a row along the longitudinal direction, each of which is a hole that penetrates in the thickness direction (corresponding to the ink ejection direction, which is typically along the vertical direction).

[0056] A liquid-repellent film 111a is formed on the ink ejection side surface of the nozzle plate 111. The material contained in the liquid-repellent film 111a is not particularly limited, but may be, for example, a fluorine-based resin. The thickness of the liquid-repellent film 111a is not particularly limited, but may be, for example, 1 nm or more and less than 100 nm.

[0057] The pressure chamber forming plate 112 is provided with a plurality of pressure chambers 57 arranged in a row along the longitudinal direction (see FIG. 6), each of which is a hole penetrating the plate in the thickness direction and communicates with a corresponding nozzle 59. The pressure chamber forming plate 112 is further provided with a common supply flow path 112a and individual supply flow paths 112b arranged on one side along the row of the pressure chambers 57. The pressure chamber forming plate 112 is further provided with a common discharge flow path 112d and individual discharge flow paths 112e arranged on the other side along the row of the pressure chambers 57. A vertical supply flow path 112c communicating with the manifold 56 is provided at the end of the common supply flow path 112a. A vertical discharge flow path 112f communicating with the outlet 103c is provided at the end of the common discharge flow path 112d.

[0058] Each of the multiple pressure chambers 57 is separated by a partition wall 57a. The pressure chambers are separated from the common supply flow path 112a and the common discharge flow path 112d by a partition wall 57b. The partition walls 57a and 57b are entirely formed from a metal that can be electroplated, such as nickel (Ni). This increases the rigidity of the partition wall 57a, making the head 55 a more stable structure that is less likely to be damaged by vibration.

[0059] The common supply channel 112a distributes ink supplied from the manifold 56 via the vertical supply channel 112c. The individual supply channels 112b are provided for each pressure chamber 57, and supply the ink flowing through the common supply channel 112a to each pressure chamber 57. The individual discharge channels 112e are provided for each pressure chamber 57, and discharge ink that has not been ejected from the pressure chamber 57 to the common discharge channel 112d. The common discharge channel 112d guides ink discharged from the pressure chamber to the outlet 103c via the vertical discharge channel 127f. In this way, each channel enables the circulation of ink for each nozzle 59 that ejects ink.

[0060] The drive plate 113 has a vibration plate 57c provided on its lower surface (the surface facing the pressure chamber forming plate 112) and spaces 113a arranged at positions facing the pressure chambers 57 with the vibration plate 57c in between. Piezoelectric elements 58 are housed in the spaces 113a. The piezoelectric elements 58 are arranged for each pressure chamber 57 (for each nozzle 59) at positions facing the pressure chambers 57 with the vibration plate 57c in between.

[0061] The piezoelectric element 58 is electrically connected to the head driver 54 via electrodes (not shown) and wiring (not shown). The piezoelectric element 58 is driven in response to a drive voltage signal applied from the head driver 54 via the electrodes and wiring, thereby repeatedly generating push-mode displacements in the vibration plate 57c and the pressure chambers 57, thereby fluctuating the ink pressure and causing ink to be ejected from the nozzles 59 in response to these pressure fluctuations. In other words, the head 55 according to this embodiment is an inkjet head that ejects ink in a push mode. Note that this embodiment is not limited to a push-mode head, and may be a bend-mode or shear-mode piezoelectric head or a thermal head, as long as it has a resin portion containing a material described below.

[0062] 5A and 5B. For example, the vibration plate 57c may be disposed on the surface of the pressure chamber 57 facing the nozzle 59, and the piezoelectric element 58 may be disposed on the nozzle 59 side of the vibration plate 57c. Alternatively, the vibration plate 57c may be disposed on the side wall of the pressure chamber 57 along the ink flow direction, and the piezoelectric element 58 may be disposed inside the partition wall 57a. As long as the pressure chamber can be contracted or expanded, the vibration plate 57c and the piezoelectric element 58 may be disposed in any position.

[0063] A vertical supply channel 113c and a vertical discharge channel 113f are provided in the drive plate 113. The vertical supply channel 113c communicates with the vertical supply channel 112c at its most downstream portion. The vertical discharge channel 113f communicates with the outlet 103c.

[0064] The materials of the nozzle plate 111, the pressure chamber forming plate 112, and the drive plate 113 are not particularly limited, and known materials such as silicon (Si), nickel (Ni), stainless steel, and polyimide can be used.

[0065] The housing 114 is provided with a manifold 56 that extends along the longitudinal direction of the head 55 and communicates with all of the multiple pressure chambers 57 at their most upstream portions. The housing 114 may be a substrate made of a resin such as polyimide, or may be a substrate made of a metal such as SUS.

[0066] 7 is a diagram showing a cross-sectional view of the main components of inkjet head 55 of the present embodiment in the vicinity of pressure chamber 57. For ease of understanding, the scale of FIG. 7 is enlarged in the vertical direction of the paper.

[0067] In this embodiment, the nozzle plate 111 and the pressure chamber forming plate 112 are bonded together by an adhesive layer 210 (one embodiment of a resin portion). Furthermore, the pressure chamber forming plate 112 and the drive plate 113 are bonded together by an adhesive layer 220 (one embodiment of a resin portion). These adhesive layers are at least partially exposed to the ink flow paths (here, the pressure chambers 57).

[0068] [Resin part] These resin portions include a cured product of a composition containing an episulfide resin and a polythiol compound.

[0069] (episulfide resin) The episulfide resin is a compound having an episulfide ring. The episulfide resin may be a chain aliphatic episulfide resin, an alicyclic episulfide resin, or an aromatic episulfide resin. Only one type of episulfide resin may be used, or two or more types may be used in combination.

[0070] Examples of the chain aliphatic episulfide resin include bis(2,3-epithiopropyl) sulfide, bis(2,3-epithiopropylthio)methane, 1,2-bis(2,3-epithiopropylthio)ethane, 1,2-bis(2,3-epithiopropylthio)propane, 1,3-bis(2,3-epithiopropylthio)propane, 1,3-bis(2,3-epithiopropylthio)-2-methylpropane, 1,4-bis(2,3-epithiopropylthio)butane, 1,4-bis(2,3-epithiopropylthio)-2-methylbutane, 1,3-bis(2,3-epithiopropylthio)-2-methylbutane, 1,5-bis(2,3-epithiopropylthio)butane, 1,5-bis(2,3-epithiopropylthio)pentane, 1,5-bis(2,3-epithiopropylthio)-2-methylpentane, 1,5-bis(2,3-epithiopropylthio)-3-thiapentane, 1,6-bis(2,3-epithiopropylthio)hexane, 1,6-bis(2,3-epithiopropylthio)-2-methylhexane, 3,8-bis(2,3-epithiopropylthio)-3,6-trithiaoctane, 1,2,3-tris(2,3-epithiopropylthio)propane, 2,2-bis(2,3-epithiopropylthio)propane 1,5-bis(2,3-epithiopropylthio)-2,4-bis(2,3-epithiopropylthiomethyl)-3-thiapentane, 1,5-bis(2,3-epithiopropylthio)-2,4-bis(2,3-epithiopropylthiomethyl)-3-thiapentane, 1-(2,3-epithiopropylthio)-2,2-bis(2,3-epithiopropylthiomethyl)-4-thiahexane San, 1,5,6-tris(2,3-epithiopropylthio)-4-(2,3-epithiopropylthiomethyl)-3-thiahexane, 1,8-bis(2,3-epithiopropylthio)-4-(2,3-epithiopropylthiomethyl)-3,6-dithiaoctane, 1,8-bis(2,3-epithiopropylthio)-4,5-bis(2,3-epithiopropylthiomethyl)-3,6-dithiaoctane, 1,8-bis(2,3-epithiopropylthio)-4,4-bis(2,3-epithiopropylthiomethyl)-3,6-dithiaoctane, 1,8-bis(2,3-epithiopropylthio)-2,5-bis(2,3-epithiopropylthiomethyl)-3,6-dithiaoctane, 1,8-bis(2,3-epithiopropylthio)-2,4,5-tris(2,3-epithiopropylthiomethyl)-3,6-dithiaoctane, 1,1,1-tris[{2-(2,3-epithiopropylthio)ethyl}thiomethyl]-2-(2,3-epithiopropylthio)ethane, 1,1,2,2-tetrakis[{2-(2,3-epithiopropylthio)ethyl} [thiomethyl]ethane, 1,11-bis(2,3-epithiopropylthio)-4,8-bis(2,3-epithiopropylthiomethyl)-3,6,9-trithiaundecane, 1,11-bis(2,3-epithiopropylthio)-4,7-bis(2,3-epithiopropylthiomethyl)-3,6,9-trithiaundecane, 1,11-bis(2,3-epithiopropylthio)-5,7-bis(2,3-epithiopropylthiomethyl)-3,6,9-trithiaundecane, etc.

[0071] Examples of alicyclic episulfide resins include 1,3-bis(2,3-epithiopropylthio)cyclohexane, 1,4-bis(2,3-epithiopropylthio)cyclohexane, 1,3-bis(2,3-epithiopropylthiomethyl)cyclohexane, 1,4-bis(2,3-epithiopropylthiomethyl)cyclohexane, 2,5-bis(2,3-epithiopropylthiomethyl)-1,4-dithiane, 2,5-bis[{2-( 2,3-epithiopropylthio)ethyl}thiomethyl]-1,4-dithiane, 2,5-bis(2,3-epithiopropylthiomethyl)-2,5-dimethyl-1,4-dithiane, 2,2-bis(4-(2,3-epithiopropoxy)cyclohexyl)propane, bis(4-(2,3-epithiopropoxy)cyclohexyl)methane, 4,8-bis(4-(2,3-epithiopropoxymethyl)-tricyclo[5.2.1.0 2.6]decane, 3,9-bis(4-(2,3-epithiopropoxymethyl)-tricyclo[5.2.1.0 2.6]decane, 3,8-bis(4-(2,3-epithiopropoxymethyl)-tricyclo[5.2.1.0 2.6]decane, 4,8-bis(4-(2,3-epithiopropoxy)-tricyclo[5.2.1.0 2.6]decane, 3,9-bis(4-(2,3-epithiopropoxy)-tricyclo[5.2.1.0 2.6]decane, 3,8-bis(4-(2,3-epithiopropoxy)-tricyclo[5.2.1.0 2.6]decane, 1,1,1-tris-(4-(2,3-epithiopropoxy)cyclohexyl)ethane, 1-(2-(2,3-epithiopropoxy)cyclohexyl)-1,1-bis-(4-(2,3-epithiopropoxy)cyclohexyl)ethane, 1,1,2,2-tetrakis-(4-(2,3-epithiopropoxy)cyclohexyl)ethane, etc.

[0072] Examples of the aromatic episulfide resin include 1,2-bis(2,3-epithiopropylthio)benzene, 1,3-bis(2,3-epithiopropylthio)benzene, 1,4-bis(2,3-epithiopropylthio)benzene, 1,2-bis(2,3-epithiopropylthiomethyl)benzene, 1,3-bis(2,3-epithiopropylthiomethyl)benzene, 1,4-bis(2,3-epithiopropylthiomethyl)benzene, bis{4-(2,3-epithiopropylthio)phenyl}methane, 2,2-bis{4-(2,3-epithiopropylthio)phenyl}propane, bis{4-(2,3-epithiopropylthio)phenyl}sulfide, bis{4-(2,3-epithiopropylthio)phenyl}sulfone, 4,4′-bis(2,3-epithiopropylthio)biphenyl, and the like.

[0073] From the viewpoint of more effectively suppressing swelling of the resin portion due to high alcohol concentration ink, alicyclic episulfide resins and aromatic episulfide resins are preferred.

[0074] (epoxy resin) The resin portion may contain an episulfide resin and an epoxy resin in combination. The epoxy resin may be used alone or in combination of two or more types.

[0075] From the viewpoint of improving the heat resistance, chemical resistance, swelling resistance, and durability of the resin part, the epoxy resin preferably contains a polyepoxy compound (referred to as epoxy compound A) having an epoxy equivalent of 110 g / eq or less and three or more epoxy groups. This polyepoxy compound preferably has an epoxy equivalent of 80 g / eq or more and 105 g / eq or less, and more preferably 90 g / eq or more and 100 g / eq or less. Furthermore, this polyepoxy compound preferably has three to six epoxy groups, and more preferably three to four epoxy groups.

[0076] Examples of the polyepoxy compound include compounds represented by formulas (1) to (5).

[0077] [ka]

[0078] In formula (1), R 1 represents a methyl group, an ethyl group, a propyl group, or an isopropyl group. s represents an integer of 0 to 4.

[0079] [ka]

[0080] In formula (2), R 2 and R 3 R independently represents a methyl group, an ethyl group, a propyl group, or an isopropyl group. 4 represents a methylene group, an ethylidene group, or an isopropylidene group. t and u each independently represent an integer of 0 to 4.

[0081] [ka]

[0082] In formula (3), R 5 represents a methyl group, an ethyl group, a propyl group, or an isopropyl group. p represents an integer of 0 to 4.

[0083] [ka]

[0084] In formula (4), R 6 represents a methyl group, an ethyl group, a propyl group, or an isopropyl group. q represents an integer of 0 to 4.

[0085] [ka]

[0086] From the viewpoint of achieving a good balance between ease of production of the resin part and adhesiveness, the resin part preferably further contains a compound represented by formula (6) (referred to as epoxy compound B) as an epoxy resin.

[0087] [ka]

[0088] In formula (6), R 7 and R 8 each independently represents a hydrogen atom or a methyl group.

[0089] From the viewpoint of achieving a good balance between ease of production of the resin part and adhesiveness, the resin part preferably further contains a compound represented by formula (7) (referred to as epoxy compound C) as an epoxy resin.

[0090] [ka]

[0091] In formula (7), r independently represents 0, 1, or 2. m represents an integer of 0 to 50. R 9 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 3 each independently represents a divalent linking group represented by formula (8).

[0092] [ka]

[0093] In formula (8), * represents a binding site. 10 and R 11 each independently represents a hydrogen atom or an unsubstituted or fluorine-substituted methyl group, and n represents an integer of 4 to 12.

[0094] The compound represented by formula (7) is R 9Examples of alkyl groups that may be taken include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a t-butyl group.

[0095] From the viewpoint of more effectively suppressing swelling of the resin portion due to high alcohol concentration ink, the compound represented by formula (7) is preferably a compound represented by formula (9).

[0096] [ka]

[0097] The resin portion may be a cured product of a composition containing other epoxy compounds. Examples of other epoxy compounds include polyglycidyl ether compounds of mononuclear polyhydric phenol compounds such as hydroquinone, resorcinol, pyrocatechol, and phloroglucinol, polyglycidyl ethers of polyhydric alcohols such as ethylene glycol, propylene glycol, butylene glycol, hexanediol, polyglycol, thiodiglycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, and bisphenol A-alkylene oxide adducts, maleic acid, fumaric acid, itaconic acid, succinic acid, glutaric acid, suberic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, trimer acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, trimesic acid, pyromellitic acid, tetrahydrophthalic acid, and hexahydrophthalic acid. Examples of epoxy compounds include glycidyl esters of aliphatic, aromatic, or alicyclic polybasic acids such as tetrahydrophthalic acid and endomethylenetetrahydrophthalic acid; homopolymers or copolymers of glycidyl methacrylate; epoxidized cyclic olefin compounds such as vinylcyclohexene diepoxide, dicyclopentadiene diepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-6-methylcyclohexanecarboxylate, and bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate; epoxidized conjugated diene polymers such as epoxidized polybutadiene and epoxidized styrene-butadiene copolymers; and heterocyclic compounds such as triglycidyl isocyanurate. The epoxy compounds may be internally crosslinked with a prepolymer of terminal isocyanates or polymerized with a polyvalent active hydrogen compound. Examples of the active hydrogen compounds include polyhydric phenols, polyamines, carbonyl-containing compounds, and polyphosphate esters.

[0098] From the viewpoint of more effectively suppressing swelling of the resin portion due to high-alcohol concentration ink, the content of epoxy compound A in the composition is preferably 5% by mass or more, and more preferably 10% by mass or more and 90% by mass or less.

[0099] From the viewpoint of achieving a good balance between ease of production of the resin part and adhesiveness, the content of epoxy compound B in the composition is preferably 1% by mass or more and 20% by mass or less, and more preferably 2% by mass or more and 10% by mass or less.

[0100] From the viewpoint of more effectively suppressing swelling of the resin part due to high-alcohol concentration ink while also increasing the ease of manufacturing the resin part, the content of epoxy compound C in the composition is preferably 5% by mass or more and 80% by mass or less, and more preferably 10% by mass or more and 50% by mass or less.

[0101] (Polythiol compounds) The polythiol compound acts as a curing agent for the episulfide compound and the epoxy compound. Examples of the polythiol compound include aliphatic polythiol compounds, aromatic polythiol compounds, polythiol compounds having an ether bond, and polythiol compounds having an ester bond. These polythiol compounds may be addition-modified with an epoxy compound. The polythiol compound may be used alone or in combination of two or more types.

[0102] Examples of aliphatic polythiol compounds include pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(thioglycolate), dipentaerythritol hexakis(3-mercaptopropionate), dipentaerythritol hexakis(3-mercaptobutyrate), 1,3,4,6-tetrakis(2-mercaptoethyl)-1,3,4,6-tetraazaochydropentalene-2,5-dione, 1,3,5-tris(3-mercaptopropyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-triazin-2,4,6-dione, and 1,3,5-tris(3-mercaptopropyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-triazin-2,4,6-dione. ion, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 4,8-, 4,7-, or 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 1,3,4,6-tetrakis(2-mercaptoethyl)glycoluril, 1,2,3-tris(mercaptomethylthio)propane, 1,2,3-tris(2-mercaptoethylthio)propane, 1,2,3-tris(3-mercaptopropylthio)propane, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane 4,7-Dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-Dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, tetrakis(mercaptomethylthiomethyl)methane, tetrakis(2-mercaptoethylthiomethyl)methane, tetrakis(3-mercaptopropylthiomethyl)methane, 1,1,3,3-tetrakis(mercaptomethylthio)propane, 1,1,2,2-tetrakis(mercaptomethylthio) Ethane, 4,6-bis(mercaptomethylthio)-1,3-dithiane, 1,1,5,5-tetrakis(mercaptomethylthio)-3-thiapentane, 1,1,6,6-tetrakis(mercaptomethylthio)-3,4-dithiahexane, 2,2-bis(mercaptomethylthio)ethanethiol, 3-mercaptomethylthio-1,7-dimercapto-2,6-dithiaheptane, 3,6-bis(mercaptomethylthio)-1,9-dimercapto-2,5,8-trithianonane, 3-mercaptomethylthio-1,6-dimercapto-2,5-dithiahexane, 1,1,9,9-tetrakis(mercaptomethylthio)-5-(3,3-bis(mercaptomethylthio)-1-thiapropyl)3,7-dithianonane, tris(2,2-bis(mercaptomethylthio)ethyl)methane, tris(4,4-bis(mercaptomethylthio)-2-thiabutyl)methane, tetrakis(2,2-bis(mercaptomethylthio)ethyl)methane, tetrakis(4,4-bis(mercaptomethylthio)-2-thiabutyl)methane, 3,5,9,11-tetrakis(mercaptomethylthio)-1,13-dimercapto-2,6,8,12-tetrathia Atridecane, 3,5,9,11,15,17-hexakis(mercaptomethylthio)-1,19-dimercapto-2,6,8,12,14,18-hexathianonadecane, 9-(2,2-bis(mercaptomethylthio)ethyl)-3,5,13,15-tetrakis(mercaptomethylthio)-1,17-dimercapto-2,6,8,10,12,16-hexathiaheptadecane, 3,4,8,9-tetrakis(mercaptomethylthio)-1,11-dimercapto-2,5,7,10-tetrathiaundecane, 3,4,8,9,13,14-hexakis(methylthio) bis(mercaptomethylthio)-1,16-dimercapto-2,5,7,10,12,15-hexathiahexadecane, 8-[bis(mercaptomethylthio)methyl]-3,4,12,13-tetrakis(mercaptomethylthio)-1,15-dimercapto-2,5,7,9,11,14-hexathiapentadecane, 4,6-bis[3,5-bis(mercaptomethylthio)-7-mercapto-2,6-dithiaheptylthio]-1,3-dithiane, 4-[3,5-bis(mercaptomethylthio)-7-mercapto-2,6-dithiaheptylthio]-6-mercaptomethylthio thiaundecane, 1,5-bis[4-(6-mercaptomethylthio)-1,3-dithianylthio]-3-[2-(1,3-dithietanyl)]methyl-2,4-dithiapentane, 1,1-bis[4-(6-mercaptomethylthio)-1,3-dithianylthio]-1,3-bis(mercaptomethylthio)propane, 1-[4-(6-mercaptomethylthio)-1,3-dithianylthio]-3-[2,2-bis(mercaptomethylthio)ethyl]-7,9-bis(mercaptomethylthio)-2,4,6,10-tetrathiaundecane, 1,5-bis[4-(6-mercaptomethylthio)-1,3-dithianylthio]-3-[2-(1,3-dithietanyl)]methyl-2,4-dithiapentane, 3-[2-(1,3-dithietanyl)]methyl-7,9-bis(mercaptomethylthio)-1,11-dimercapto-2,4,6,10-tetrathiaundecane, 9-[2-(1,3-dithietanyl)]methyl-3,5,13,15-tetrakis(mercaptomethylthio)-1,17-dimercapto-2,6,8,10,12,16-hexathiaheptadecane, 3-[2-(1,3-dithietanyl)]methyl-7,9,13,15-tetrakis(mercaptomethylthio)-1,17-dimercapto-2,4,6,10,12,16-hexathiaheptadecane, and 3,7-bis[2-(1,3-dithietanyl)]methyl-1,9-dimercapto-2,4,6,8-tetrathianonane.

[0103] Other examples of polythiol compounds include 4,6-bis{3-[2-(1,3-dithietanyl)]methyl-5-mercapto-2,4-dithiapentylthio}-1,3-dithiane, 4,6-bis[4-(6-mercaptomethylthio)-1,3-dithianylthio]-6-[4-(6-mercaptomethylthio)-1,3-dithianylthio]-1,3-dithiane, 4-[3,4,8,9-tetrakis(mercaptomethylthio)-11-mercapto-2,5,7,10-tetrathiaundecyl]-5-mercaptomethylthio-1,3-dithiolane, 4,5-bis(mercaptomethylthio)-1,3-dithianylthio]-6-[4-(6-mercaptomethylthio)-1,3-dithianylthio]-1,3-dithiane, bis[3,4-bis(mercaptomethylthio)-6-mercapto-2,5-dithiahexylthio]-1,3-dithiolane, 4-[3,4-bis(mercaptomethylthio)-6-mercapto-2,5-dithiahexylthio]-5-mercaptomethylthio-1,3-dithiolane, 4-[3-bis(mercaptomethylthio)methyl-5,6-bis(mercaptomethylthio)-8-mercapto-2,4,7-trithiaoctyl]-5-mercaptomethylthio-1,3-dithiolane, 2-{bis[3,4-bis(mercaptomethylthio)-6-mercapto-2, 5-dithiahexylthio]methyl}-1,3-dithietane, 2-[3,4-bis(mercaptomethylthio)-6-mercapto-2,5-dithiahexylthio]mercaptomethylthiomethyl-1,3-dithietane, 2-[3,4,8,9-tetrakis(mercaptomethylthio)-11-mercapto-2,5,7,10-tetrathiaundecylthio]mercaptomethylthiomethyl-1,3-dithietane, 2-[3-bis(mercaptomethylthio)methyl-5,6-bis(mercaptomethylthio)-8-mercapto-2,4,7-trithiaoctyl]mercapto mercaptomethylthiomethyl-1,3-dithietane, 4,5-bis{1-[2-(1,3-dithietanyl)]-3-mercapto-2-thiapropylthio}-1,3-dithiolane, 4-{1-[2-(1,3-dithietanyl)]-3-mercapto-2-thiapropylthio}-5-[1,2-bis(mercaptomethylthio)-4-mercapto-3-thiabutylthio]-1,3-dithiolane, 2-{bis[4-(5-mercaptomethylthio-1,3-dithiolanyl)thio]methyl}-1,3-dithietane, and 4-[4-(5-mercaptomethylthio-1,3-dithiolanyl)thio]-5-{1-[2-(1,3-dithietanyl)]-3-mercapto-2-thiapropylthio}-1,3-dithiolane, etc.

[0104] From the viewpoint of enhancing the durability of the resin portion when a high-alcohol concentration ink is repeatedly ejected, the polythiol compound preferably has four or more thiol groups. Six or more thiol groups are more preferable. The upper limit of the number of thiol groups is not particularly limited, but can be 10 or less, preferably six or less. Furthermore, the greater the number of thiol groups in the polythiol compound, the easier it is to achieve a good balance between the storage stability and curability of the composition when it is made into a one-component composition. However, the composition is not limited to a one-component composition, and may be a two-component composition in which a liquid containing an episulfide resin and an epoxy resin is separated from a liquid containing a polythiol compound. Alternatively, the composition may be a three-component composition in which a liquid containing an episulfide resin, a liquid containing an epoxy resin, and a liquid containing a polythiol compound are separated.

[0105] (quantity ratio) The above-mentioned episulfide resin, epoxy resin and polythiol compound can be used in any ratio.

[0106] The amount of polythiol compound in the composition can be 0.2 to 2.0 equivalents per equivalent of epoxy resin, preferably 0.8 to 1.2 equivalents, and more preferably 0.9 to 1.1 equivalents. When the amount of polythiol compound is 0.2 equivalents or more, the curability of the composition is improved. When the amount of polythiol compound is 2.0 equivalents or less, the heat resistance and durability are improved.

[0107] The amount of episulfide resin in the composition can be 10 parts by mass or more and 300 parts by mass or less, preferably 20 parts by mass or more and 200 parts by mass or less, and more preferably 30 parts by mass or more and 150 parts by mass or less, relative to 100 parts by mass of the total amount of epoxy resin and polythiol compound. When the amount of episulfide resin is 10 parts by mass or more, swelling of the resin part due to high alcohol concentration ink can be more effectively suppressed. When the amount of episulfide resin is 300 parts by mass or less, the durability of the resin part is less likely to decrease.

[0108] (curing catalyst) From the viewpoint of improving the durability of the resin portion when the high-alcohol concentration ink is repeatedly ejected, it is preferable that the composition contains a curing catalyst. The curing catalyst may be used alone or in combination of two or more types.

[0109] Examples of the curing catalyst include phosphine compounds such as triphenylphosphine, phosphonium salts such as tetraphenylphosphonium bromide, imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 1-cyanoethyl-2-methylimidazole, 1-{3-[(3-trimethoxysilyl)propylaminocarbonylamino]propyl}-2-methylimidazole, 1-[3-trimethoxysilylpropylaminomethyl]-4-methylimidazole, 1-[3-(trimethoxysilylpropyl)]imidazole, 1-[3-(trimethoxysilylpropyl)]imidazole, and 1-benzyl-2-methylimidazole, and mixtures of the above imidazoles with trimellitic acid, These include imidazole salts, which are salts with isocyanuric acid, boron, etc., amines such as benzyldimethylamine and 2,4,6-tris(dimethylaminomethyl)phenol, quaternary ammonium salts such as trimethylammonium chloride, ureas such as 3-(p-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-phenyl-1,1-dimethylurea, isophorone diisocyanate-dimethylurea, and tolylene diisocyanate-dimethylurea, complex compounds of boron trifluoride with amines or ether compounds, polyepoxy compounds or isocyanate adducts of amine compounds having one or more active hydrogens, and amine-based latent curing agents obtained by combining these with phenolic resins. Of these, imidazoles and amines are preferred.

[0110] The content of the curing catalyst in the composition can be from 0.1 to 10% by mass, preferably from 0.2 to 5.0% by mass, and more preferably from 0.5 to 3.0% by mass, based on the total amount of the resin components. The resin components refer to curable resins such as episulfide resins and epoxy resins.

[0111] Examples of the amine compound having one or more active hydrogens that can provide the amine-based latent curing agent include alkylenediamines such as ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,3-diaminobutane, 1,4-diaminobutane, and hexamethylenediamine; polyalkylpolyamines such as diethylenetriamine, triethylenetriamine, and tetraethylenepentamine; 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 1,3-diaminomethylcyclohexane, 1,2-diaminocyclohexane; Alicyclic polyamines such as cyclohexane, 1,4-diamino-3,6-diethylcyclohexane, 4,4'-diaminodicyclohexylmethane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 4,4'-diaminodicyclohexylpropane, bis(4-aminocyclohexyl)sulfone, 4,4'-diaminodicyclohexyl ether, 2,2'-dimethyl-4,4'-diaminodicyclohexylmethane, isophoronediamine, and norbornenediamine, m-xylylenediamine, diaminodiphenyl Aromatic polyamines such as methane, diaminodiphenyl sulfone, diethyltoluenediamine, 1-methyl-3,5-diethyl-2,4-diaminebenzene, 1-methyl-3,5-diethyl-2,6-diaminobenzene, 1,3,5-triethyl-2,6-diaminobenzene, 3,3'-diethyl-4,4'-diaminodiphenylmethane, and 3,5,3',5'-tetramethyl-4,4'-diaminodiphenylmethane; guanamines such as benzoguanamine and acetoguanamine; 2-methylimidazole, 2-ethyl-4-methylimidazole imidazoles such as 2-isopropylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 2-aminopropylimidazole; dihydrazides such as oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, suberic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, and phthalic acid dihydrazide; N,N-dimethylaminoethylamine;N-Diethylaminoethylamine, N,N-Diisopropylaminoethylamine, N,N-Diallylaminoethylamine, N,N-Benzylmethylaminoethylamine, N,N-Dibenzylaminoethylamine, N,N-Cyclohexylmethylaminoethylamine, N,N-Dicyclohexylaminoethylamine, N-(2-aminoethyl)pyrrolidine, N-(2-aminoethyl)piperidine, N-(2-aminoethyl)morpholine, N-(2-aminoethyl)piperazine, N-(2-aminoethyl)-N'-methylpiperazine, N,N-Dimethylaminoethylamine N-(3-aminopropyl)pyrrolidine, N-(3-aminopropyl)piperidine, N-(3-aminopropyl)morpholine, N-(3-aminopropyl)piperazine, N-(3-aminopropyl) -N'-Methylpiperidine, 4-(N,N-dimethylamino)benzylamine, 4-(N,N-diethylamino)benzylamine, 4-(N,N-diisopropylamino)benzylamine, N,N,-dimethylisophoronediamine, N,N-dimethylbisaminocyclohexane, N,N,N'-trimethylethylenediamine, N'-ethyl-N,N-dimethylethylenediamine, N,N,N'-trimethylethylenediamine, N'-ethyl-N,N-dimethylpropanediamine, N'-ethyl-N,N-dibenzylaminopropylamine; N,N-(bimethyl) N,N-bisaminopropyl)-N-methylamine, N,N-bisaminopropylethylamine, N,N-bisaminopropylpropylamine, N,N-bisaminopropylbutylamine, N,N-bisaminopropylpentylamine, N,N-bisaminopropylhexylamine, N,N-bisaminopropyl-2-ethylhexylamine, N,N-bisaminopropylcyclohexylamine, N,N-bisaminopropylbenzylamine, N,N-bisaminopropylallylamine, bis[3-(N,N-dimethylaminopropyl)]amine, bis[3-(N,Bis[3-(N,N-diethylaminopropyl)]amine, bis[3-(N,N-diisopropylaminopropyl)]amine, bis[3-(N,N-dibutylaminopropyl)]amine, etc.

[0112] Examples of epoxy compounds that can provide the amine-based latent curing agent include polyglycidyl ether compounds of mononuclear polyhydric phenol compounds such as hydroquinone, resorcinol, pyrocatechol, and phloroglucinol, dihydroxynaphthalene, biphenol, methylene bisphenol (bisphenol F), methylene bis(ortho-cresol), ethylidene bisphenol, isopropylidene bisphenol (bisphenol A), isopropylidene bis(ortho-cresol), tetrabromobisphenol A, and 1,3-bis(4-hydroxycumylbenzene). Polyglycidyl ether compounds of polynuclear polyhydric phenols such as 1,4-bis(4-hydroxycumylbenzene), 1,1,3-tris(4-hydroxyphenyl)butane, 1,1,2,2-tetra(4-hydroxyphenyl)ethane, thiobisphenol, sulfonylbisphenol, oxybisphenol, phenol novolac, orthocresol novolac, ethylphenol novolac, butylphenol novolac, octylphenol novolac, resorcinol novolac, and terpene phenols, ethylene glycol, propylene glycol Polyglycidyl ethers of polyhydric alcohols such as glycerin, butylene glycol, hexanediol, polyglycol, thiodiglycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, and bisphenol A-alkylene oxide adducts, maleic acid, fumaric acid, itaconic acid, succinic acid, glutaric acid, suberic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, trimer acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, trimesic acid, pyromellitic acid, tetrahydrophthalic acid, hexahydrophthalic acid Glycidyl esters of aliphatic, aromatic or alicyclic polybasic acids such as phthalic acid and endomethylenetetrahydrophthalic acid, homopolymers or copolymers of glycidyl methacrylate, epoxy compounds having glycidylamino groups such as N,N-diglycidylaniline, bis(4-(N-methyl-N-glycidylamino)phenyl)methane and diglycidyl orthotoluidine, vinylcyclohexene diepoxide, dicyclopentadiene diepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,These include epoxidized cyclic olefin compounds such as 4-epoxy-6-methylcyclohexylmethyl-6-methylcyclohexanecarboxylate and bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, epoxidized conjugated diene polymers such as epoxidized polybutadiene and epoxidized styrene-butadiene copolymers, and heterocyclic compounds such as triglycidyl isocyanurate.

[0113] Examples of polyisocyanate compounds that can provide the amine-based latent curing agent include aromatic diisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate, phenylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, 1,5-naphthylene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, 3,3'-dimethyldiphenyl-4,4'-diisocyanate, dianisidine diisocyanate, and tetramethylxylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, and tetramethylxylylene diisocyanate. Examples of suitable diisocyanates include alicyclic diisocyanates such as trans-1,4-cyclohexyl diisocyanate and norbornene diisocyanate, aliphatic diisocyanates such as tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4 and / or (2,4,4)-trimethylhexamethylene diisocyanate, and lysine diisocyanate, isocyanurate trimer, biuret trimer, and trimethylolpropane adducts of the above-exemplified diisocyanates, triphenylmethane triisocyanate, 1-methylbenzene-2,4,6-triisocyanate, and dimethyltriphenylmethane tetraisocyanate.

[0114] These polyisocyanate compounds may be modified, such as carbodiimide-modified, isocyanurate-modified or biuret-modified, or may be blocked isocyanates blocked with various blocking agents.

[0115] Examples of phenolic resins that can provide the above-mentioned amine-based latent curing agent include polyhydric phenol compounds such as phenol novolac resin, cresol novolac resin, aromatic hydrocarbon formaldehyde resin-modified phenolic resin, dicyclopentadiene phenol adduct resin, phenol aralkyl resin (Xyloc resin), naphthol aralkyl resin, trisphenylolmethane resin, tetraphenylolethane resin, naphthol novolac resin, naphthol-phenol co-condensed novolac resin, naphthol-cresol co-condensed novolac resin, biphenyl-modified phenolic resin (a polyhydric phenol compound in which phenol nuclei are linked via bismethylene groups), biphenyl-modified naphthol resin (a polyhydric naphthol compound in which phenol nuclei are linked via bismethylene groups), aminotriazine-modified phenolic resin (a compound having a phenol skeleton, a triazine ring, and a primary amino group in its molecular structure), and alkoxy group-containing aromatic ring-modified novolac resin (a polyhydric phenol compound in which phenol nuclei and alkoxy group-containing aromatic rings are linked via formaldehyde).

[0116] (Other ingredients) The composition may optionally contain known additives such as reactive or non-reactive diluents (plasticizers) such as monoglycidyl ethers, dioctyl phthalate, dibutyl phthalate, benzyl alcohol, and coal tar; fillers or pigments such as glass fiber, carbon fiber, cellulose, silica sand, cement, kaolin, clay, aluminum hydroxide, bentonite, talc, silica, finely divided silica, titanium dioxide, carbon black, graphite, iron oxide, and bitumen; lubricants such as candelilla wax, carnauba wax, Japan wax, ivory wax, beeswax, lanolin, spermaceti, montan wax, petroleum wax, fatty acid wax, fatty acid esters, fatty acid ethers, aromatic esters, and aromatic ethers; thickeners, thixotropic agents, antioxidants, light stabilizers, UV absorbers, flame retardants, antifoaming agents, rust inhibitors, and colloidal silica and colloidal alumina. The composition may also contain adhesive resins such as xylene resins and petroleum resins.

[0117] (Manufacturing method of resin part) The resin part can be made by applying a composition containing these materials and then heating and curing it while applying a certain amount of pressure as needed. Heating can be carried out at a temperature of 80°C to 100°C. Heating can be carried out for 1 hour to 4 hours.

[0118] (Thickness) The adhesive layer 210 as a resin portion (the bonding portion that bonds the nozzle plate 111 and the pressure chamber forming plate 112) preferably has a thickness of 0.5 μm or more and 4.0 μm or less. A thickness of 0.5 μm or more sufficiently increases the adhesive strength and can suppress ink leakage between the nozzles. A thickness of 4.0 μm or less can make it less likely that nozzles will be missing due to resin leaking into the nozzles.

[0119] The adhesive layer 220 as a resin part (the joint that joins the pressure chamber forming plate 112 and the drive plate 113) preferably has a thickness of 0.1 μm or more and 2.5 μm or less. A thickness of 0.1 μm or more can sufficiently increase the adhesive strength. A thickness of 2.5 μm or less can sufficiently increase the volume of the pressure chambers 57, thereby sufficiently increasing the amount of ink ejection.

[0120] (Impregnation rate) The impregnation rate of these resin parts when immersed in 100% ethanol for two weeks is preferably less than 4.0%, more preferably 3.8% or less, and even more preferably 3.7% or less. The impregnation rate is the value shown in (1) below. Impregnation rate (%) = (mass before TGA heating - mass after TGA heating) / (mass before TGA heating) × 100 (1)

[0121] More specifically, the impregnation rate is measured as follows: The resin portion scraped off from the head 55 is weighed, immersed in 100% ethanol, and stored in a sealed container at 60°C for one week. After one week, the sample is removed from the solution and left for one hour at 22°C and 50% RH, and then TGA measurement is performed using the sample. In the TGA measurement, the sample temperature is raised from 30°C to 100°C at a rate of 7°C / min, and then held for one hour. The sample is weighed before and after heating, and the impregnation rate is calculated using the following formula. Impregnation rate = (mass of sample before TGA heating - mass of sample after TGA heating) / (mass of sample before TGA heating)

[0122] These resin portions (adhesive layer 210 and adhesive layer 220) are disposed so as to be at least partially exposed to the ink flow path. According to the findings of the present inventors, high-alcohol-concentration ink easily penetrates into the resin exposed to the flow path inside the head 55. If these resin portions swell or dissolve due to the permeating ink, the head 55 may be deformed, or stress may be concentrated locally, causing peeling, which may result in problems such as missing nozzles. In particular, when the head 55 has a structure that circulates ink, the ink is constantly flowing, making it easy for swelling due to penetration into the resin portions to occur. Furthermore, even when a fluctuating waveform is used when ink is not being ejected, the ink is constantly flowing, making it easy for swelling due to penetration into the resin portions and resulting problems to occur.

[0123] In contrast, the resin portion obtained by curing a composition containing an episulfide resin and a thiol is less likely to swell even when it comes into contact with high-alcohol-concentration ink in the head 55. This is thought to be because the episulfide resin reacts with the thiol compound during curing, forming a sulfide bond. Unlike the oxide bonds that form when epoxy resins cure, the sulfide bonds that form when episulfide resins cure are less likely to form hydrogen bonds with the hydroxyl groups of alcohols. Therefore, it is thought that the resin portion formed from the above material is less likely to be penetrated by ink and to swell even when it comes into contact with high-alcohol-concentration ink. According to the inventors' findings, the resin portion is less likely to swell or be damaged by ink, even when circulating ink or using a vibrating waveform.

[0124] Either adhesive layer 210 or adhesive layer 220 may be a resin part formed from the above-mentioned material, or both may be resin parts formed from the above-mentioned material. Furthermore, a resin part at least partially exposed to the ink flow path other than these adhesive layers may be a resin part formed from the above-mentioned material. For example, an adhesive layer bonding another plate, an adhesive layer bonding piezoelectric element 58 and diaphragm 57C, an adhesive layer bonding substrates together when forming manifold 56 by bonding substrates, and an adhesive layer bonding the main body of head chip 110 to a cap receiving plate that exposes the nozzles and covers their undersides may be resin parts formed from the above-mentioned material.

[0125] [ink] The ink contains, as a solvent component, an alcohol having 1 to 4 carbon atoms in an amount of 60 to 95% by mass relative to the total mass of the ink. Such ink has excellent quick-drying properties. The amount of the alcohol having 1 to 4 carbon atoms in the ink is preferably 70 to 95% by mass.

[0126] Alcohols having 1 to 4 carbon atoms include methanol, ethanol, 1-propanol, 2-propanol (isopropyl alcohol), 1-butanol, isobutanol, 2-methyl-1-propanol (isobutyl alcohol), 2-butanol (sec-butyl alcohol), and 2-methyl-2-propanol (tert-butyl alcohol). Of these, methanol, ethanol, 1-propanol, and 2-propanol are preferred.

[0127] Among alcohols having 1 to 4 carbon atoms, ethanol is more preferred because it dries quickly and is highly safe, eliminating the need for environmental protection equipment. In this case, ethanol may be used alone as the solvent component, or ethanol may be used in combination with another alcohol having 1 to 4 carbon atoms. When the ink contains a phenolic resin or terpene phenolic resin (discussed below) as a tackifier, it is preferable to use 1-propanol or 1-butanol in combination with ethanol to enhance the solubility of these resins. From these perspectives, the amount of ethanol in the ink is preferably 30% to 95% by mass, and more preferably 30% to 50% by mass. A small amount of 2-propanol, for example, may be used as long as its impact on the human body is negligible.

[0128] The ink may contain solvent components other than alcohols having 1 to 4 carbon atoms. From the viewpoint of improving the solubility of the ink, it is preferable that these solvent components have a boiling point of 120°C or higher. On the other hand, from the viewpoint of sufficiently improving the quick-drying properties of the ink, it is preferable that the amount of solvents having a boiling point of 120°C or higher is not too large. Therefore, the amount of solvent components other than alcohols in the ink is preferably 0% by mass or more and 25% by mass or less, and more preferably 0% by mass or more and 15% by mass or less.

[0129] The ink preferably contains a phenolic resin to improve adhesion to low-polarity media such as films. Only one type of phenolic resin may be used, or two or more types may be used in combination. Furthermore, the phenolic resin is preferably a novolac resin because it is thermoplastic and easily improves adhesion. Furthermore, from the viewpoint of improving adhesion, the softening point of the phenolic resin is preferably 70°C or higher and 125°C or lower, more preferably 80°C or higher and 120°C or lower, and even more preferably 90°C or higher and 110°C or lower. The softening point of the phenolic resin is the arithmetic average of the upper and lower limits of the Vicat softening temperature (VST) measured in accordance with JIS K7206:1997.

[0130] The amount of phenol resin in the ink is preferably 2% by mass or more and 20% by mass or less, more preferably 3% by mass or more and 15% by mass or less, and even more preferably 3% by mass or more and 8% by mass or less.

[0131] The ink may also contain tackifiers such as terpene phenolic resins and rosin ester resins.

[0132] The ink may also contain known dyes or pigments, binder resins, surfactants, lubricants, and the like.

[0133] Such ink is likely to soak into the resin portion inside the head and cause the resin portion to swell. However, in this embodiment, a head having the above-described resin portion is used, so swelling of the resin portion due to the ink is unlikely to occur.

[0134] Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the specific embodiments described above. Various modifications and changes to the specific examples described in the above embodiments are possible within the scope of the gist of the present invention as defined in the claims. [Example]

[0135] The present invention will be described in detail based on examples, but the present invention is not limited to these examples.

[0136] 1. Inkjet Head Fabrication As the main components of the adhesive, an episulfide resin (episulfide) having the structure shown in (10) below, an aminophenol-type epoxy resin (epoxy 1) having the structure shown in (11) below, a phenol novolac-type epoxy resin (epoxy 2) having the structure shown in (12) below, and a bisphenol F-type epoxy resin (epoxy 3) having the structure shown in (13) below were prepared.

[0137] [ka]

[0138] [ka]

[0139] [ka]

[0140] [ka]

[0141] The polythiol compounds prepared were pentaerythritol hexakis(3-mercaptopropionate) (polythiol 1), dipentaerythritol hexakis(3-mercaptopropionate) (polythiol 2), and tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate (polythiol 3).

[0142] As curing catalysts, 1-benzyl-2-methylimidazole (curing catalyst 1) and N-benzyldimethylamine (curing catalyst 2) were prepared.

[0143] A nozzle plate made of SUS304, a pressure chamber forming plate made of SUS304, and a driving plate (vibration plate) made of a metal containing Ni and equipped with a piezoelectric element and electrodes were prepared.

[0144] The above materials were mixed while cooling to form a resin composition. The nozzle plate, whose surface had been cleaned, was coated at the location where the pressure chamber forming plate would be placed, so that the thickness after curing would be 2.0 μm. The pressure chamber forming plate was then brought into contact with the coated resin composition and heated to 90°C. After 4 hours, it was confirmed that the resin composition had hardened to form an adhesive layer, and the pressure chamber forming plate was bonded to the nozzle plate.

[0145] The surface of the drive plate was then cleaned and coated with a resin composition at the position where the pressure chamber forming plate would be placed, so that the thickness after curing would be 1.5 μm. The side of the pressure chamber forming plate to which the nozzle plate had been attached was then brought into contact with the coated resin composition, and heated to 90°C. After 3 hours, it was confirmed that the resin composition had hardened to form an adhesive layer, and the pressure chamber forming plate had been bonded to the nozzle plate.

[0146] The thus obtained assembly in which the nozzle plate, pressure chamber forming plate and drive plate were bonded together was used to form a simulated inkjet head.

[0147] 2. Ink Preparation The ink materials used were ethanol, 1-butanol, propylene glycol monoethyl ether (a solvent with a boiling point of 120°C or higher), Solvent Black 29 (a dye), Phenolite TD-2131 (a novolac resin, softening point VT (°C) = 80°C) (phenolic resin) manufactured by DIC Corporation, and Phenolite TD-2090 (a novolac resin, softening point VT (°C) = 120°C) (phenolic resin) manufactured by DIC Corporation.

[0148] These were mixed in the ratios shown in Table 1 to obtain inks 1 to 3. The values ​​in the table are in mass %.

[0149] [Table 1]

[0150] 3. Evaluation 3-1.Durability The ink was filled into the flow path of the fabricated inkjet head and stored in a warmer maintained at 60°C. After 1 month, 2 months, and 3 months of storage, wiring was connected to the piezoelectric element of the inkjet head and the ink was ejected, and the ink was evaluated according to the following criteria. A: Even after 3 months of storage, no nozzles had ejection problems. B: No nozzles had ejection problems until after two months of storage, but after three months of storage, some nozzles had ejection problems. C: No nozzles had ejection problems until one month after storage, but after two months of storage, some nozzles had ejection problems. D: After one month of storage, a nozzle with poor ejection occurred.

[0151] 3-2.Impregnation rate After peeling off the nozzle plate of the inkjet head, 5 mg of the remaining adhesive was scraped off. The scraped adhesive was weighed, immersed in 100% ethanol, and stored in a sealed state at 60°C for two weeks. After two weeks, the sample was removed from the solution and dried for one hour before TGA measurement. For TGA measurement, the sample temperature was raised from 30°C to 100°C at a rate of 7°C / min, and then held for one hour. The sample was weighed before and after heating, and the impregnation rate was calculated using the following formula. Impregnation rate = (mass of sample before TGA heating - mass of sample after TGA heating) / (mass of sample before TGA heating)

[0152] Based on the calculated impregnation rate, the evaluation was made according to the following criteria. A: Impregnation rate less than 4.0% B: Impregnation rate is 4.0% or more

[0153] 3-3. Quick drying Using an inkjet head (Konica Minolta, KM1024i) and an evaluation machine, inks 1 to 3 were ejected onto the surface of a nylon film, and after 10 seconds, the film was pressed with paper (Epson, KA4100PSKR) and then pulled away. The state of color transfer onto the paper was observed and evaluated according to the following criteria. A: There was no color transfer to the paper. There was also no effect on printing. B: There was a very slight amount of color transfer to the paper, but it did not affect the print. C: There was a significant amount of color transfer to the paper, which affected the printing.

[0154] Table 2 shows the resin composition and ink used to prepare the inkjet head, as well as the evaluation results.

[0155] [Table 2]

[0156] As shown in Table 2, the inkjet head containing the cured product of the composition containing the episulfide resin and the polythiol compound in the resin portion was less likely to suffer from swelling of the resin portion due to high alcohol concentration.

[0157] This application claims priority from Japanese Patent Application No. 2024-078101, filed May 13, 2024. The entire disclosures of the specification, claims, and drawings of that application as originally filed are incorporated herein by reference. [Industrial Applicability]

[0158] The present invention can achieve both the quick drying properties of high alcohol concentration ink and the durability of the inkjet head. [Explanation of symbols]

[0159] 1. Inkjet printer 10 Conveying section 11 Conveyor belt 11a Conveying surface 12 Drive roller 13 Driven roller 20 Supply section 21 Storage area 22 Unwinding roller 30 Discharge section 31 Storage area 32 Winding roller 40 Ink supply unit 41 Main Tank 42 Flow path 50 Drawing section 51 Carriage 52a 1st subtank 52b Second subtank 53a, 53b, 53c flow channels 54 Head drive unit 55 Inkjet head 56 Manifold (common supply flow path) 57 Pressure Chamber 57a, 57b bulkhead 57c diaphragm 58 Piezoelectric element 59 nozzle 60 Reading unit 70 Operation display section 80 Input / Output Interface 90 Control Unit 91 CPU 92 RAM 93 ROM 94 Memory section 95 Drying section 99 External device 101 Case 102 Exterior materials 103a Inlet 103b, 103c Outlet 104 mounting holes 110 Head Chip 111 Nozzle plate 111a Liquid repellent film 112 Pressure chamber forming plate 112a common supply channel 112b Individual supply channel 112c Vertical supply channel 112d Common discharge flow path 112e Individual discharge flow path 112f Vertical discharge channel 113 Drive Plate 113a Space part 113c Vertical supply channel 113f Vertical discharge channel 114 Housing 210, 220 adhesive layer

Claims

1. A method for forming an image by ejecting ink from an inkjet head, comprising: the inkjet head has an ink flow path and a resin portion at least partially exposed to the ink flow path; the resin portion includes a cured product of a composition including an episulfide resin and a polythiol compound, the ink contains an alcohol having 1 to 4 carbon atoms in an amount of 60% by mass to 95% by mass relative to the total mass of the ink; Image forming method.

2. the ink contains ethanol in an amount of 30% by mass or more relative to the total mass of the ink; The image forming method according to claim 1 .

3. The resin portion is a cured product of a composition further containing a curing catalyst. The image forming method according to claim 1 .

4. The curing catalyst comprises an amine or an imidazole. The image forming method according to claim 3 .

5. The cured product is immersed in 100% ethanol in a 60°C environment for two weeks, and then the sample temperature is raised from 30°C to 100°C at a rate of 7°C / min, and then maintained for one hour in TGA measurement. The impregnation rate calculated from the mass of the cured product using the following formula (1) is less than 4.0%. The image forming method according to claim 1 . Impregnation rate (%) = (mass before TGA heating - mass after TGA heating) / (mass before TGA heating) × 100 (1)

6. The polythiol compound is a compound having four or more thiol groups. The image forming method according to claim 1 .

7. the resin portion is a joining portion that joins the vibration plate and the pressure chamber forming substrate; The image forming method according to claim 1 .

8. The resin portion has a thickness of 0.1 μm or more and 2.5 μm or less. The image forming method according to claim 7.

9. the resin portion is a joining portion that joins the nozzle plate and the pressure chamber forming substrate; The image forming method according to claim 1 .

10. The resin portion has a thickness of 0.5 μm or more and 4.0 μm or less. The image forming method according to claim 9.

11. the inkjet head circulates the ink for each nozzle that ejects the ink; The image forming method according to claim 1 .

12. the inkjet head causes the ink to flow by a vibration waveform when the ink is not being ejected; The image forming method according to claim 1 .

13. forming an image on a recording medium conveyed by a roll-to-roll method; The image forming method according to claim 1 .

Images