JP4987318B2 - Ink jet head and manufacturing method thereof - Google Patents

Description

The present invention relates to Lee inkjet head and a manufacturing method thereof.

  Conventionally, “screen printing technology” in which a desired pattern is formed on a mesh-like screen and ink that has passed through the pattern is printed on a recording medium has been produced by manufacturing a liquid crystal color filter, applying a liquid crystal alignment film, and organic EL ( Widely applied to the production of various precision electronic components such as ElectroLuminescence).

  However, the above screen printing technology requires a simple and inexpensive design because the screen must be designed and manufactured in advance before printing, or a new screen must be designed and manufactured every time the pattern is changed. However, in recent years, “inkjet technology” capable of recording images and the like easily and inexpensively has begun to be applied as an alternative to the screen printing technology.

  The ink jet technology is a technology for recording an image or the like on a recording medium by scanning an “ink jet head” that ejects ink as droplets on the recording medium. In the screen printing technique, a resin recording medium is used as the recording medium. Therefore, when using the inkjet technology as an alternative technology to the screen printing technology (when applying a resin recording medium as the recording medium), the ink is likely to penetrate the resin as a recording medium. “Solvent ink” that can improve the durability of the medium itself is used.

Here, the ink jet head is composed of adhesive members, but when solvent-based ink is applied, the solvent-based ink dissolves the adhesive. It is preferable to use an “epoxy adhesive” that is resistant to solvents. An example of an epoxy adhesive is disclosed in Patent Document 1. Specifically, in the technique described in Patent Document 1, the temperature rising rate from room temperature to 100 ° C. is set slowly to dry and cure the adhesive, thereby increasing the crosslink density and increasing the resistance to solvent-based ink. (See paragraph numbers 0034 to 0041).
JP 2003-266708 A

  By the way, although the said epoxy-type adhesive agent contains "epoxy resin" and "curing agent", the reaction mechanism for the said epoxy-type adhesive agent to cure | harden with the kind of hardening | curing agent differs. In general, an “amine curing agent” is often used as the curing agent, and an “imidazole curing agent” is sometimes applied.

  In an amine-based epoxy adhesive to which an amine-based curing agent is applied as a curing agent, the activity of the primary amine present in the amine-based curing agent is high, and the primary amine opens the epoxy group in the epoxy resin at room temperature. A ring is added to this to produce a secondary amine and a hydroxyl group, and this reaction is repeated to grow a chain in a linear form. When the secondary amine further reacts with an epoxy group in the epoxy resin, a tertiary amine and a hydroxyl group are generated, and this reaction is repeated to form a three-dimensional crosslinked structure. For these reasons, amine-based epoxy adhesives have a certain degree of resistance to solvents.

  However, in an amine-based epoxy adhesive, an amine-based curing agent is incorporated into the above-mentioned crosslinked structure and a hydroxyl group is included. Therefore, the amine-based epoxy adhesive absorbs a solvent and easily swells. Has drawbacks. Therefore, the amino group and hydroxyl group remaining in the crosslinked structure may be reacted with an unreacted epoxy group. However, when the reaction is started, the crosslinked structure is already formed at that point and the glass transition point is high. Therefore, the reaction cannot be started unless the glass transition point is heated. From the above, in order to sufficiently cure the amine-based epoxy adhesive, it must be heated at a high temperature of 150 to 200 ° C. or higher.

  In contrast, an imidazole-based epoxy adhesive to which an imidazole-based curing agent is applied as a curing agent has a curing reaction mechanism different from that of the amine-based curing agent, and imidazole functions as a catalyst for initiating a curing reaction. When the reaction is started, the epoxy resins are crosslinked by an ether bond. In this reaction mechanism, a polar group is not contained in the cross-linked product, and the distance between cross-linking points is also short. From such circumstances, the imidazole-based epoxy adhesive does not have the disadvantage of absorbing the solvent unlike the amine-based epoxy adhesive, and has resistance to the solvent.

  However, when a general epoxy resin such as bisphenol A type epoxy resin or bisphenol F type epoxy resin is used in combination with a general imidazole curing agent, a high temperature of about 150 ° C. is required to obtain sufficient solvent resistance. Must be heated at.

  Ink-jet heads basically have different linear expansion coefficients (thermal expansion coefficients) among the members that make up the ink-jet head. When cured at a high temperature, when the temperature returns to room temperature after curing, Due to the difference in shrinkage rate, stress due to the difference in shrinkage is applied between the cured adhesive and the member.

  As a result, the adhesive itself is cracked or the adhesive strength is reduced. In particular, when the inkjet head is transported as a product, or when it is subjected to repeated operations of operation and stop of the inkjet head, it is subject to repeated temperature fluctuations, and cracks and adhesive strength are likely to occur. . Further, when attention is paid to the member, there is a possibility that the member is cracked, the member is distorted, or one member is peeled off from the other member.

  Furthermore, when the ink jet head has a piezoelectric element as one constituent member, if the adhesive is cured at a high temperature, depolarization occurs in the piezoelectric element, and the performance of the piezoelectric element decreases.

An object of the present invention has a resistance to solvent-based inks, cracking of parts member, distortion is to provide an ink jet head and a manufacturing method thereof capable of preventing the peeling.

The first invention is
An ink-jet head comprising: a channel substrate having an ink channel; a member to be bonded to the channel substrate; and a second member to be bonded to the member to be bonded.
The channel substrate and the adherend member, or the adherend member and the second adherend member are bonded with the following adhesive,
The adhesive is an adhesive in which a main agent and a curing agent are mixed,
The main agent contains a first epoxy resin having a bifunctional or lower functional group and a second epoxy resin having a trifunctional or higher functional group, and the first epoxy resin is 20 to 90 in the main agent. And the second epoxy resin is contained in an amount of 10 to 80% by weight in the main agent,
The curing agent is an imidazole,
6 parts by weight or more of the curing agent is mixed with 100 parts by weight of the main agent, and the first epoxy resin is a bisphenol F type epoxy resin .

In the inkjet head of the first aspect of the invention,
There may be a difference in linear expansion coefficient exceeding 12 ppm / K between the channel substrate and the adherend member or between the adherend member and the second adherend member.

The second invention is
An ink-jet head comprising: a channel substrate having an ink channel; a member to be bonded to the channel substrate; and a second member to be bonded to the member to be bonded.
The channel substrate and the adherend member, or the adherend member and the second adherend member are bonded with the following adhesive,
The adhesive is an adhesive in which a main agent and a curing agent are mixed,
The main agent contains a first epoxy resin having a bifunctional or lower functional group and a second epoxy resin having a trifunctional or higher functional group, and the first epoxy resin is 20 to 90 in the main agent. And the second epoxy resin is contained in an amount of 10 to 80% by weight in the main agent,
The curing agent is an imidazole,
6 parts by weight or more of the curing agent is mixed with 100 parts by weight of the main agent, and a silane coupling agent is added .

In the inkjet head of the second aspect of the invention,
There may be a difference in linear expansion coefficient exceeding 12 ppm / K between the channel substrate and the adherend member or between the adherend member and the second adherend member.

Here, when the linear expansion coefficient differs between the adherend member and the second adherend member to a level exceeding 12 ppm / K, the curing temperature suitable for the combination of a general epoxy resin and a general imidazole curing agent is set. When applied, there arises a problem that peeling occurs, a member breaks, or an ink ejection speed distribution becomes large. However, the present invention ( first and second inventions) can solve the above problems.

The third invention is
An inkjet head manufacturing method for manufacturing the inkjet head of the first invention ,
Between the bonded component and the channel substrate, or the between the second adherend member and bonded component, coated with the adhesive, by adding 60 ° C. less heat to the adhesive wherein the adhesive is cured, and the bonded component and the channel substrate, or the is characterized by adhering the second adherend member and bonded component.

The fourth invention is:
An inkjet head manufacturing method for manufacturing the inkjet head of the second invention ,
Between the bonded component and the channel substrate, or the between the second adherend member and bonded component, coated with the adhesive, by adding 60 ° C. less heat to the adhesive wherein the adhesive is cured, and the bonded component and the channel substrate, or the is characterized by adhering the second adherend member and bonded component.

In the first or second invention, since the channel substrate and the member to be bonded or the member to be bonded and the second member to be bonded are bonded with the above adhesive, the cured adhesive and the channel substrate, The stress acting between the adhesive member or the second adherend member can be relieved, and as a result, the channel substrate, the adherend member or the second adherend member is cracked, the channel substrate, the adherend member Alternatively, it is possible to prevent the second adherend from being distorted, the adherend from being peeled off from the channel substrate, and the second adherend from being peeled off from the adherend.

When there member is bonded with both the above adhesive channel substrate and the bonded component is a "bonded component" of the relationship between the member and the channel substrate and the first or second aspect of the invention " Corresponding to the relationship with the “channel substrate”, and the relationship between the member and the bonded member corresponds to the relationship between the “second bonded member” and the “bonded member” of the first or second invention. . At this time, if either one of the relations satisfies the relation described in the first or second invention, the above effect can be obtained.

In 3rd or 4th invention, in order to harden the said adhesive agent by applying the heat of 60 degrees C or less to the said adhesive agent, the temperature difference at the time of the temperature of the adhesive agent after hardening falling to room temperature from the curing temperature is The stress acting between the adhesive and the channel substrate, the member to be bonded, or the second member to be bonded is relieved. Therefore, the channel substrate, the adherend member or the second adherend member is cracked, the channel substrate, the adherend member or the second adherend member is distorted, the adherend member is peeled off from the channel substrate, It is possible to prevent the second adherend from peeling off from the adherend. Furthermore, in the third or fourth invention, when the channel substrate is composed of a piezoelectric element, it is possible to prevent depolarization from occurring in the piezoelectric element.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, although various technically preferable limitations for carrying out the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples.

FIG. 1 is a side sectional view showing a schematic configuration of an inkjet head 100 according to the present invention.
As shown in FIG. 1, the ink jet head 100 has a channel substrate 1 on which an ink flow path (channel 3) is formed. A cover plate 2 is bonded to the upper portion of the front side of the channel substrate 1 via an adhesive portion a. The cover plate 2 is made of a material such as glass, ceramics, metal, or resin.

  A nozzle plate 5 having an ejection port 4 for ejecting ink as droplets is bonded to the front end surfaces of the channel substrate 1 and the cover plate 2 via an adhesive portion b. The channel substrate 1 is formed with a channel 3 (groove) extending from the center portion to the front end portion, and the channel 3 communicates with the discharge port 4 of the nozzle plate 5. The nozzle plate 5 is made of a resin such as polyimide.

FIG. 2 is an exploded perspective view showing the main configuration of the channel substrate 1, the cover plate 2 and the nozzle plate 5.
As shown in FIG. 2, the channel substrate 1 has a configuration in which two substrates 1a and 1b are bonded to each other through an adhesive portion j. Each of the substrates 1a and 1b is made of a piezoelectric material such as lead zirconate titanate (PZT) and is polarized in opposite directions in the thickness direction. In the channel substrate 1, a plurality of channels 3, 3,... Are formed at equal intervals, and a partition wall 6 is formed between the channels 3. That is, channels 3 and partition walls 6 are alternately formed on the channel substrate 1.

  Each channel 3 is a groove cut out from the center portion to the front end portion of the channel substrate 1, and is cut out from the substrate 1 a to the middle portion of the substrate 1 b in the thickness direction of the channel substrate 1. In particular, each channel 3 is gently inclined in the rear part from the upper part of the substrate 1a to the middle part of the substrate 1b in the direction from the rear to the front, and the ink smoothly flows into the channel 3 from above the substrate 1a. It is like that.

  In the channel substrate 1 having the above-described configuration, the cover plate 2 is bonded to the upper portion of the substrate 1a so as to cover the top of each channel 3, and the front end surface of the channel substrate 1 so that the discharge port 4 communicates with each channel 3. The nozzle plate 5 is bonded to the nozzle plate 5.

FIG. 3 is a sectional view taken along line AA in FIG.
As shown in FIG. 3, an electrode film 7 made of metal such as aluminum is formed in a U shape on the inner wall of each channel 3, and is formed on the inner wall of each electrode film 7 and a part of the lower part of the bonding portion a. The protective film 8 is formed into a rectangular shape. Each protective film 8 protects the electrode film 7 and is made of insulating poly-p-xylylene.

  In the inkjet head 100, since the substrates 1a and 1b are polarized in opposite directions as described above, when a voltage is applied to each electrode film 7 in the state shown in FIG. As shown in the figure, each partition wall 6 is bent (sheared) in a square shape (or reverse square shape) around the bonding portion j with the substrates 1a and 1b. In this case, the internal volume of each channel 3 changes and the pressure applied to the ink fluctuates. When the pressure reaches a predetermined value, the ink is ejected from the ejection port 4. On the other hand, when the voltage application is canceled in the state of FIG. 4B in which a voltage is applied to each electrode 7, each partition 6 returns to the original state as shown in FIG. 4C. It has become.

  As shown in FIG. 1, an ink tube 10 for supplying ink to each channel 3 is disposed above the channel substrate 1. The ink tube 10 has one end connected to a tank (not shown) that stores ink, and the other end connected to the manifold 11. The manifold 11 functions as a joint that connects the ink tube 10 and the channel substrate 1. The ink tube 10 is bonded to the manifold 11 via the bonding portion h, and the manifold 11 is bonded to the channel substrate 1 and the cover plate 2 via bonding portions e and f, respectively.

  A metal filter 12 having a mesh shape is disposed inside the manifold 11. The filter 12 removes foreign matter in the ink from the ink, and is bonded to the manifold 11 via the bonding portion g.

  An FPC (Flexible Print Cable) 20 is disposed behind the channel substrate 1. The FPC 20 is bonded to the channel substrate 1 via the bonding portions c and i. In particular, the bonding portion i is a portion that reinforces the FPC 20 to the channel substrate 1 so that the FPC 20 does not peel from the channel substrate 1. Although not shown in detail, the FPC 20 is energized with the electrode film 7 formed on each channel 3.

  A driving IC (Integrated Circuit) 21 is bonded to the FPC 20 via a bonding portion d. The drive IC 21 functions as a voltage generation source for shearing and deforming each partition wall 6 of the channel substrate 1. The drive IC 21 generates the voltage based on the image signal transferred through the FPC 20 and supplies the voltage through the FPC 20. The voltage is applied to the electrode film 7.

  In the inkjet head 100 having the above-described configuration, the other portions are substantially covered with the box-shaped housing 30 with the nozzle plate 5 protruding. Specifically, an opening 31 is formed in the housing 30, and the front ends of the channel substrate 1 and the cover plate 2 are fitted in the opening 31.

  Further, in the inkjet head 100, the members bonded via the bonding portions a to j have a difference in linear expansion coefficient exceeding 12 ppm / K (only some members are mutually 12 ppm / K). (It may have a difference in linear expansion coefficient exceeding K). For example, taking as an example the channel substrate 1 and the manifold 11 bonded via the bonding portion e, the difference between the linear expansion coefficient of the channel substrate 1 and the linear expansion coefficient of the manifold 11 exceeds 12 ppm / K. .

  When the nozzle plate 5 is made of polyimide, the difference between the linear expansion coefficient of the nozzle plate 5 and the linear expansion coefficient of the channel substrate 1 exceeds 12 ppm / K. In this case, in this embodiment, the channel The discharge port 4 of the nozzle plate 5 is bonded to the channel 3 of the substrate 1 in a state of being displaced, or the adhesive constituting the bonding part b flows into the discharge port 4 and the ink discharge performance is deteriorated. Absent.

  Here, each adhesion part ai which adhere | attaches the said members is comprised from the following "adhesive", and the said adhesive which concerns on this invention is demonstrated in detail below.

  The adhesive according to the present invention is a mixture of “(1) main agent” and “(2) curing agent”, and more than 6 parts by weight of the curing agent (preferably 100 parts by weight of the main agent with respect to 100 parts by weight of the main agent). 8 parts by weight or more of the curing agent).

(1) Main agent The main agent is composed of “(1.1) first epoxy resin” having a functional group of two or less functions and “(1.2) second epoxy resin” having a functional group of three or more functions. The epoxy equivalent of the whole main ingredient is 150 or less.

(1.1) First epoxy resin The first epoxy resin is contained in the main agent in an amount of 20 to 90% by weight. As the first epoxy resin, a bisphenol F-type epoxy resin is applicable, and specific examples thereof include Epicoat 806, 807 (manufactured by Japan Epoxy Resin), RE303S-L (manufactured by Nippon Kayaku Co., Ltd.), and the like. It is done.

(1.2) Second epoxy resin The second epoxy resin is contained in an amount of 10 to 80% by weight in the main agent. Examples of the second epoxy resin include triglycidyl-p-aminophenol, tetraglycidyl diaminodiphenylmethane, triglycidyl isocyanurate, triglycidyl urazole, triglycidyl amino cresol, tetraglycidyl-1,3-diaminomethyl cyclohexane, glycerol tri Glycidyl ether or the like is applicable.

Furthermore, a “novolak epoxy resin” may be applied as the second epoxy resin.
As the novolac epoxy resin, “phenol novolac type epoxy resin” and “cresol novolac type epoxy resin” are applicable.
Specific examples of the phenol novolac type epoxy resin include EPPN 201, 202 (manufactured by Nippon Kayaku), Epicoat 154 (manufactured by Japan Epoxy Resin), DEN-438 (manufactured by Dow Chemical) and the like.
Specific examples of the cresol novolac type epoxy resin include EOCN102, 103S, 104S, 1020, 1025, 1027 (manufactured by Nippon Kayaku), Epicoat 180S (manufactured by Japan Epoxy Resin) and the like.

  Among these compounds of the second epoxy resin, it is particularly preferable to apply triglycidyl-p-aminophenol from the viewpoint of solvent resistance.

  In applying the main agent, any one of the above (1.2) epoxy resins and the above (1.1) epoxy resin may be combined, or the above (1.2) different plural You may combine a seed epoxy resin and the epoxy resin of said (1.1).

(2) Curing agent As the curing agent, imidazoles (imidazole in which 1-position or 1-position and 2-position are substituted with an alkyl group) can be applied. Examples of the alkyl group include branched and straight chain alkyl groups such as methyl group, ethyl group, isopropyl group, t-butyl group, hexyl group, dodecyl group, and pentadecyl group, and cyclic alkyl groups such as cyclopentyl group and cyclohexyl group. These alkyl groups may have a substituent. Examples of the substituent include alkyl groups, alkenyl groups, aryl groups, heterocyclic groups, halogen atoms, alkoxy groups, aryloxy groups, alkoxycarbonyl groups, aryloxycarbonyl groups, sulfonamido groups, sulfamoyl groups, ureido groups, and acyl groups. , Acyloxy group, carbamoyl group, alkylsulfonyl group, arylsulfonyl group, cyano group, nitro group, sulfo group, hydroxyl group and the like. In the imidazoles substituted at the 1-position with an alkyl group, a substituent may be arranged at positions other than the 1-position, and in the imidazoles substituted at the 1-position and the 2-position with an alkyl group, the 1-position and the 2-position. Substituents may be arranged at positions other than the above, and as the substituent, those exemplified as the substituents arranged on the alkyl group can be applied.

  Specific examples of imidazole substituted at the 1-position or 1-position and 2-position with an alkyl group include 1-methylimidazole, 1-benzyl-2-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole. 1-methyl-2-ethylimidazole, 1-ethylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1- (2-hydroxy-3-phenoxypropyl)- Examples include 2-ethyl-4-methylimidazole and 1- (2-hydroxy-3-phenoxypropyl) -2-methylimidazole.

  From the cured adhesive, the imidazole ring-containing compound and the compound having three or more epoxy groups are detected in a form in which the epoxy group is eliminated by thermal decomposition GC mass spectrum. Moreover, an imidazole ring containing compound is detected by solid state NMR.

  The adhesive according to the present invention may contain “(3) resin fine particles”, “(4) silane coupling agent”, and “(5) zirconate” as additives. These additives may be added alone, or two or more additives may be added simultaneously.

(3) Resin fine particles As the resin fine particles, particles such as a copolymer of methyl methacrylate and butyl acrylate are applicable.

(4) Silane coupling agent As the silane coupling agent, γ-aminopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxy Aminosilane coupling agents such as silane, N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, and γ-glycidoxy Epoxysilane coupling agents such as propyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and γ-glycidoxypropylmethyldiethoxysilane are applicable.

(5) Zirconate As the zirconate, neopentyl (diallyl) oxytrineodecanoyl zirconate, neopentyl (diallyl) oxytri (dodecyl) benzene-sulfonyl zirconate, neopentyl (diallyl) oxy tri (p-amino) benzoate zirconate ( LZ-37), tetrapropylzirconate, tetrabutylzirconate, tetra (ethanolamine) zirconate, tetraisopropylzirconate, isopropyltri (n-aminoethyl-aminoethyl) zirconate, diisopropyldi (4-aminobenzoyl) zirconate, Tris-2-propoxy (2-ethylamino) ethyl zirconate, tris [(2,2-bis-2-propenyloxymethyl) butoxy] ethylenediaminoethoxydi Luconate is applicable.

The “ink” ejected from the inkjet head 100 is composed of a coloring material such as a dye or a pigment or a solvent (solvent) for dissolving the coloring material, and the type thereof is not particularly limited. A solvent having a Solubility Parameter value ((cal / cm) ^1/2 ) of 9.5 to 15.0 and a dipole efficiency of 2.0 to 5.0 is 3% by weight or more based on the total solvent. It is preferable from the viewpoint of fixability of a printed image, and according to the present embodiment, the durability of such ink is not deteriorated. Specific examples of the solvent include N, N-dimethylformamide (SP value = 12.1, dipole efficiency = 3.86), N-methyl-2-pyrrolidinone (SP value = 11.3, dipole efficiency = 4.09), ethyl lactate (SP value = 10.0, dipole efficiency = 2.14), cyclohexanone (SP value = 9.9, dipole efficiency = 3.01), 2-pyrrolidinone (SP value = 14) .7, dipole efficiency = 3.83).

  Here, the dipole efficiency is calculated by MOPAC AM1, and the SP value is calculated by the Bicerano method. The “Bicerano method” is described in Prediction of Polymer Properties (Plastics Engineering, 65) Jozef Bicerano (Author).

  Next, the “method for manufacturing the inkjet head 100” according to the present invention will be described.

  First, the adhesive is applied to the two flat substrates 1a and 1b, and the substrates 1a and 1b are bonded together (to form an adhesive portion j). The adhesive portion j is heated to 60 ° C. (preferably 40 ° C.). C.) The following heat is applied to cure the bonding portion j, thereby bonding the substrates 1a and 1b. When the channel substrate 1 is manufactured by bonding the substrates 1a and 1b, a plurality of channels 3, 3,... Are formed on the channel substrate 1 using a dicing blade or the like, and a known vapor deposition process is performed on the inner wall of each channel 3. To form an electrode film 7 in each channel 3.

  After the electrode film 7 is formed on the inner wall of each channel 3, the adhesive is applied to the upper part of the substrate 1 a of the channel substrate 1 and the cover plate 2 is bonded (forms an adhesive part a). The bonding portion a is cured by applying heat of 60 ° C. (preferably 40 ° C.) or less, and the cover plate 2 is bonded to the upper portion of the substrate 1a as shown in FIGS. 5 (a) and 5 (b) (FIG. 5 ( (b) is sectional drawing which follows the BB line in Fig.5 (a), and each adhesion part a and j and the electrode film 7 are not illustrated in Fig.5 (a)-(c).

  When the cover plate 2 is bonded, the inner wall of the electrode film 7 is subjected to a poly-p-xylylene treatment by a CVD (Chemical Vapor Deposition) method to form a protective film 8 inside each channel 3. When the protective film 8 is formed, as shown in FIG. 5C, the central portion of the channel substrate 1 and the cover plate 2 is cut along the direction orthogonal to the length direction of each channel 3 (divided into two parts). ) Two pieces of head chips 101 are manufactured (the electrode film 7 and the protective film 8 are not shown in FIG. 5C).

  After the head chip 101 is manufactured, the adhesive is applied to each end face of the channel substrate 1 and the cover plate 2, and the nozzle plate 5 is bonded to each end face so that each discharge port 4 communicates with the channel 3 ( The adhesive part b is formed), and heat of 60 ° C. (preferably 40 ° C.) or less is applied to the adhesive part b to cure the adhesive part b, and the nozzle plate 5 Glue.

  After the nozzle plate 5 is bonded, an adhesive is applied to members such as the manifold 11, the FPC 20, and the casing 30 other than the above that constitute the inkjet head 100, and these members are bonded to predetermined positions of the head chip 101 (adhesion portion c). To j), heat of 60 ° C. (preferably 40 ° C.) or less is applied to the bonding portions c to i to cure the bonding portions c to i, and the members and the head chip 101 are bonded. The ink jet head 100 according to the present invention can be manufactured through the processes of the above steps.

  In this embodiment, each time the adhesive portions aj are formed, the adhesive portions aj are heated to cure the adhesive portions aj, but all the adhesive portions aj are formed. Then, all the bonded portions a to j may be cured at once by applying heat to all the bonded portions a to j after bonding all the members together.

  Next, the operation / action of the inkjet head 100 will be described.

  When ink flows from the ink tank (not shown) through the ink tube 10 to the manifold 11 through the ink tube 10, foreign matter is removed through the filter 12 and stored in the manifold 11 and each channel 3 ( (See arrow in FIG. 1).

  In this state, when the image signal is transferred to the drive IC 21 through the FPC 20, the drive IC 21 generates a drive voltage for shearing deformation of each partition wall 6 of the channel substrate 1 based on the image signal, and the drive signal is driven through the FPC 20. A voltage is applied to each electrode film 7.

  When each electrode film 7 is applied with a driving voltage, each partition wall 6 is shear-deformed into a square shape or a reverse square shape around the bonding portion j of the substrates 1a and 1b (from the state shown in FIG. 4A). 4B), the internal volume of each channel 3 changes and the pressure applied to the ink fluctuates. When the pressure reaches a predetermined value, the inkjet head 100 ejects ink from the ejection port 4 as droplets.

  In the above embodiment, each adhesive part aj is comprised with the said adhesive agent, and at the time of manufacturing the inkjet head 100, 60 degrees C or less heat | fever is applied to each adhesive part aj, and it is made to harden | cure. Therefore, the stress that acts between each of the bonded portions a to j after curing and the member bonded thereby (for example, between the bonded portion a and the channel substrate 1 or the cover plate 2) is relaxed.

That is, the “stress P” generated between the adhesive and the adherend to be bonded is obtained by the following formula (A).
P≈EΔα (t ₂ −t ₁ ) (A)
In the formula (A), E: elastic modulus of the adhesive, Δα: difference in linear expansion coefficient between the adhesive and the member to be bonded, t ₂ : curing temperature (temperature of heat applied to the adhesive), t ₁ : room temperature

Based on the above formula (A), for example, the elastic modulus of the bonded portion a is 3430 MPa, the linear expansion coefficient of the channel substrate 1 is 2 × 10 ⁻⁶ / ° C., and the linear expansion coefficient of the bonded portion a is 8 × 10 ⁻ Assuming ⁵ / ° C. and applying 100 ° C. heat to the bonded portion a to cure the bonded portion a, the stress generated when the bonded portion a returns to room temperature (25 ° C.) is 20 0.07 MPa, and a stress of about 20 MPa is generated between the bonding portion a and the channel substrate 1. In this case, it is considered that the channel substrate 1 bends and compressive stress is applied to the inside of the channel substrate 1 itself, and as a result, the channel substrate 1 is partially depolarized and causes ink ejection fluctuations. .

  However, when the adhesive part a is cured by applying 60 ° C. heat to the adhesive part a as in this embodiment, the stress generated when the adhesive part a returns to room temperature (25 ° C.) is 9 .3 MPa, the stress generated between the bonded portion a and the channel substrate 1 is substantially halved, and the stress acting between the bonded portion a and the channel substrate 1 is relaxed.

  From the above, each of the bonded portions a to j after curing is bonded to the channel substrate 1, the member to be bonded (the cover plate 2, the nozzle plate 5, the manifold 11, etc.) or the member to be bonded. The stress acting between the second adherend (manifold 11, ink tube 10, filter 12, etc.) is alleviated, and each member constituting the inkjet head 1 is cracked or distorted. It is possible to prevent the other member from peeling off from one member.

  In particular, when the manifold 11 is molded from a thermoplastic resin, the molding is easy, but the manifold 11 has a large linear expansion coefficient, and the difference in linear expansion coefficient between the channel substrate 1 and the cover plate 2 is large. Is more than 12 ppm / K, and since the cross-sectional area is large, the stress received from the channel substrate 1 and the cover plate 2 is large (in contrast, the channel substrate 1 and the cover plate 2 are also subjected to a large stress from the manifold 11). . Therefore, in this case, the channel substrate 1, the cover plate 2, and the manifold 11 are likely to be cracked, distorted, peeled off, and the like, but in this embodiment, these members are bonded with the above-mentioned adhesive. , Distortion, peeling and the like can be effectively prevented.

(Reference example)
(1.1) Preparation of Samples 1 to 13 The main agent and the curing agent are mixed (optionally resin fine particles, silane coupling agent and zirconate are also mixed), and the mixture is 0.1 to 0.2 g of granules per grain. The product was dropped on a Teflon (registered trademark) sheet. Thereafter, each dropped granular material was allowed to stand at 45 ° C. for 10 hours to be cured to produce an adhesive tablet, which were designated as “Samples 1 to 13”. The composition of each sample 1 to 13 (presence / absence and type of main agent, curing agent, resin fine particles, silane coupling agent and zirconate) is as shown in Table 1 below.

(1.2) Measurement of mass increase rate of samples 1 to 13 After preparing samples 1 to 13, the mass of each sample 1 to 13 was measured, and each sample 1 to 13 was immersed in a solvent (N-methylpyrrolidone). And allowed to stand at 60 ° C. for 7 days. After 7 days, each sample 1 to 13 was taken out from the solvent and washed with isopropyl alcohol in a washing bottle. After washing, the isopropyl alcohol adhering to the surface of each sample 1-13 was removed, and the mass of each sample 1-13 was measured again.

The mass increase rate of each sample 1-13 was computed according to the following formula after the mass measurement again. The calculation results are as shown in Table 1 below.
Mass increase rate (%) = (((mass after solvent immersion) − (mass before solvent immersion)) / (mass before solvent immersion)) × 100

  In Table 1, “Main Agent”, “E1” is a bisphenol A type epoxy resin (bifunctional, Epicoat 828 (manufactured by Japan Epoxy Resin), 184 to 194 g / eq), and “E2” is a bisphenol F type epoxy. Resin (bifunctional, Epicoat 806 (manufactured by Japan Epoxy Resin), 160 to 170 g / eq), and “E3” is a phenol novolac type epoxy resin (trifunctional or more, Epicote 152 (manufactured by Japan Epoxy Resin)). “E4” is triglycidyl-p-aminophenol, “E5” is tetraglycidyldiaminodiphenylmethane, and the numbers in parentheses indicate the weight (parts by weight) of each compound constituting the main agent.

  In the item of Table 1 “Curing agent”, “Z1” is 2-ethyl-4-methylimidazole, “Z3” is 1-benzyl-2-methylimidazole, and “Z4” is 2,4-dimethylimidazole. "H3" is triethylenetetramine, and the numbers in parentheses indicate parts by weight of the curing agent with respect to 100 parts by weight of the main agent.

  In Table 1, “resin fine particles”, “silane coupling agent”, and “zirconate”, “A” is a copolymer particle of methyl methacrylate and butyl acrylate (average particle diameter of about 0.3 μm), and “B” ”Is γ-glycidoxypropyltrimethoxysilane,“ C ”is isopropyltri (n-aminoethyl-aminoethyl) zirconate, and the numbers in parentheses are parts by weight of the additive with respect to 100 parts by weight of the main agent. Show.

(1.3) Conclusion As shown in Table 1, the samples 1 to 6 and 13 have a very low weight change rate compared to the other samples 7 to 12, and the samples 1 to 6 and 13 are hardly dissolved in the solvent. I understand. From the above, it can be seen that adhesives having specific compositions such as Samples 1 to 6 and 13 are cured at a low temperature of 60 ° C. or lower and have resistance to solvents.

(2.1) Production of Samples 1 to 13 “First PZT substrate (thickness 150 μm, Curie temperature 210 ° C., linear expansion coefficient 4 ppm / K)” and “second PZT substrate (thickness 700 μm, Curie temperature 210) Two PZT substrates with “° C., linear expansion coefficient 4 ppm / K)” were prepared, and the first and second PZT substrates were bonded with an adhesive so that the polarization directions were opposite to each other. When bonding the first PZT substrate and the second PZT substrate, Epotec 353ND (manufactured by Rikei Co., Ltd.) is used as an adhesive, and the adhesive is heated by applying heat of 80 to 100 ° C. Cured.

  After bonding the first and second PZT substrates, a channel (groove) having a depth of 300 μm and a width of 70 μm is formed from the first PZT substrate to the second PZT substrate, and aluminum is deposited on the inner walls of the channels. Then, an electrode film made of aluminum was formed inside the channel.

  When the electrode film was formed, a cover plate (aluminum nitride having a thickness of 700 μm, linear expansion coefficient 4 ppm / K) was bonded onto the first PZT substrate with an adhesive (see FIGS. 5A and 5B). When bonding the cover plate and the first PZT substrate, Epotec 353ND (manufactured by Rikei Co., Ltd.) was used as an adhesive, and the adhesive was cured by applying heat at 80 to 100 ° C. .

  After the cover plate was bonded, the inner wall of the electrode film was subjected to poly-p-xylylene treatment by CVD to form a protective film inside the channel. When the protective film was formed, the first and second PZT substrates and the cover plate were cut along a direction orthogonal to the length direction of the channel to manufacture a head chip (see FIG. 5C).

  When the head chip was manufactured, a nozzle plate (a polyimide having a thickness of 100 μm formed with a discharge port having a diameter of 30 μm) was bonded to the head chip with an adhesive. When bonding the cover plate and the head chip (first PZT substrate), Epotec 353ND (manufactured by Rikei Co., Ltd.) is used as an adhesive, and heat is applied to the adhesive at 80 to 100 ° C. Was cured.

  After the nozzle plate was bonded, another member such as a manifold (made of polyamide, linear expansion coefficient 50 ppm / K) was bonded to the head chip with an adhesive to manufacture an inkjet head. In Example 2, 13 types of adhesives shown in Table 2 below were applied to the manifolds (adhesion between the manifold and the cover plate and adhesion between the manifold and the first PZT substrate). Each adhesive was cured by applying heat at 40 ° C. for 17 hours. And a total of 13 types of inkjet heads according to the types of these adhesives were manufactured, and these inkjet heads were designated as “Samples 1 to 13”.

(2.2) Evaluation of Samples 1 to 13 (2.2.1) Discharge Test As a substitute for ink, a mixture of 90 parts by weight of butoxyethyl acetate and 10 parts by weight of 2-pyrrolidinone was applied. The mixture was continuously discharged from 13, and the discharge performance (when ink leakage occurred) of each sample 1 to 13 was evaluated. The evaluation results are shown in Table 2 below.

(2.2.2) Heat cycle test As the first heat cycle test, 25 ° C. → (60 ° C., 1 hour) → (25 ° C., 30 minutes) → (0 ° C., 1 hour) → (25 ° C., 30 Each sample 1 to 13 was subjected to a heat cycle environment for 3 cycles, with 1 minute), and the channel of each sample 1 to 13 was depressurized to check whether there was air leakage in the channel.

  Thereafter, as the second heat cycle test, 25 ° C. → (60 ° C., 1 hour) → (25 ° C., 30 minutes) → (−20 ° C., 1 hour) → (25 ° C., 30 minutes) is one cycle. Each sample 1-13 was used for the heat cycle environment for 3 cycles, and the channel of each sample 1-13 was pressure-reduced, and it was confirmed whether there was an air leak in the said channel.

The test results are shown in Table 2 below. In the items of Table 2 “Heat cycle test”, the standards of ◎, ○, Δ, and × are as follows.
◎… There was no air leak in both the first and second heat cycle tests ○… There was no air leak in the first heat cycle test, but there was an air leak in the second heat cycle test △… The first heat Some air leaks occurred in the cycle test ×… Air leaks occurred in the first heat cycle test

(2.2.3) Observation of presence or absence of cracks After the heat cycle test, whether or not the adhesive between the cover plate and the manifold is cracked was visually observed for each of the samples 1 to 13. The observation results are shown in Table 2 below. Among the items of Table 2 “Crack”, the criteria of ○, Δ, and X are as follows.
○… No cracks △… One or two cracks were observed ×… 3 or more cracks were observed

Table 2 “Main agent”, “Curing agent”, “Resin fine particle”, “Silane coupling agent”, “Zirconate” in each item, the numbers in parentheses, etc. are the same as in Table 1 of the reference example. .

(2.3) Conclusion As shown in Table 2, the results of Samples 1 to 6 are better than those of Samples 7 to 12, and in particular, from the results of the discharge test and the heat cycle test , the inkjet of the present invention. It can be seen that the head does not cause ink leakage or air leakage and does not crack the adhesive. In the ink jet head of the present invention, no air leakage occurred, and it can be seen that there are no cracks, distortion, peeling, etc. in the member such as the manifold. From the above, it can be seen that in the inkjet heads of Samples 1 to 6, the adhesive is cured with heat of 60 ° C. or less and has excellent performance.

2 is a side sectional view showing a schematic configuration of the inkjet head 100. FIG. FIG. 3 is an exploded perspective view showing a configuration of main parts of a channel substrate 1, a cover plate 2, and a nozzle plate 5. It is sectional drawing which follows the AA line of FIG. It is a state change figure showing change of partition 6 when voltage is applied to each electrode film 7. 2 is a diagram for explaining a partial process of the method for manufacturing the inkjet head 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Inkjet head 101 Head chip aj Adhering part 1 Channel substrate 2 Cover plate (adhered member)
3 Channel 4 Discharge port 5 Nozzle plate (Adhered member)
6 Partition 7 Electrode film 8 Protective film 10 Ink tube (second adherend)
11 Manifold (Adhered member, Second Adhered member)
12 Filter (second adherend)
20 FPC (Adhered member)
21 Drive IC (second adherend)
30 housing

Claims (6)

An ink-jet head comprising: a channel substrate having an ink channel; a member to be bonded to the channel substrate; and a second member to be bonded to the member to be bonded.
  The channel substrate and the adherend member, or the adherend member and the second adherend member are bonded with the following adhesive,
  The adhesive is an adhesive in which a main agent and a curing agent are mixed,
  The main agent contains a first epoxy resin having a bifunctional or lower functional group and a second epoxy resin having a trifunctional or higher functional group, and the first epoxy resin is 20 to 90 in the main agent. And the second epoxy resin is contained in an amount of 10 to 80% by weight in the main agent,
  The curing agent is an imidazole,
  An inkjet head, wherein 6 parts by weight or more of the curing agent is mixed with 100 parts by weight of the main agent, and the first epoxy resin is a bisphenol F-type epoxy resin. The difference in linear expansion coefficient exceeding 12 ppm / K between the channel substrate and the adherend member or between the adherend member and the second adherend member. 2. An ink jet head according to 1. An ink-jet head comprising: a channel substrate having an ink channel; a member to be bonded to the channel substrate; and a second member to be bonded to the member to be bonded.
The channel substrate and the adherend member, or the adherend member and the second adherend member are bonded with the following adhesive,
The adhesive is an adhesive in which a main agent and a curing agent are mixed,
The main agent contains a first epoxy resin having a bifunctional or lower functional group and a second epoxy resin having a trifunctional or higher functional group, and the first epoxy resin is 20 to 90 in the main agent. And the second epoxy resin is contained in an amount of 10 to 80% by weight in the main agent,
The curing agent is an imidazole,
An ink jet head, wherein 6 parts by weight or more of the curing agent is mixed with 100 parts by weight of the main agent, and a silane coupling agent is added . The difference in linear expansion coefficient exceeding 12 ppm / K between the channel substrate and the adherend member or between the adherend member and the second adherend member. 4. An ink jet head according to item 3. An inkjet head manufacturing method for manufacturing the inkjet head according to claim 1, comprising:
  The adhesive is applied between the channel substrate and the adherend member, or between the adherend member and the second adherend member, and heat of 60 ° C. or less is applied to the adhesive. A method of manufacturing an ink jet head, comprising: curing the adhesive; and bonding the channel substrate and the member to be bonded, or bonding the member to be bonded and the second member to be bonded. An inkjet head manufacturing method for manufacturing the inkjet head according to claim 3, comprising:
The adhesive is applied between the channel substrate and the adherend member, or between the adherend member and the second adherend member, and heat of 60 ° C. or less is applied to the adhesive. A method of manufacturing an ink jet head, comprising: curing the adhesive; and bonding the channel substrate and the member to be bonded, or bonding the member to be bonded and the second member to be bonded.

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