JP2010253707A - Manufacturing method of ink jet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an ink jet head which has no void in an adhesive of a part that joins members, is prevented in the flow of the adhesive into an unnecessary part, has a long pot life of the adhesive, and is favorable in not only in water resistance but also solvent resistance. <P>SOLUTION: The manufacturing method of the ink jet head includes a heating step after a step of sticking a plurality of members by the adhesive which contains an epoxy resin, a cationic photo-polymerization initiator and a cationic heat polymerization initiator and a step of irradiating a protruding part of the adhesive with light where 80-100 mass% of the whole epoxy resin is an aromatic epoxy compound. In the ink jet head manufacturing method, the heating step has a step of raising temperatures in a temperature range of not lower than 40°C. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an inkjet head that is durable even when solvent ink is used as well as water-based ink.

  Liquid ejecting heads that can eject liquid in the form of minute droplets have become widespread, for example, as ink jet heads used in ink jet printers that record images by ejecting ink droplets onto recording paper.

  As a typical ink discharge method of an ink jet head, a method of vaporizing and expanding water in the ink by heat generated by flowing an electric current through an electric resistor disposed in a pressurizing chamber and applying pressure to the ink to discharge the ink, Each of the piezoelectric bodies is formed by using a part of the flow path member constituting the pressure chamber and a piezoelectric body or by installing a piezoelectric body in the flow path member and selectively driving the piezoelectric bodies corresponding to the plurality of nozzles. There is a method in which a liquid is discharged from a nozzle by deforming a pressurizing chamber based on the dynamic pressure of the nozzle.

  In recent years, the interval between adjacent nozzles is becoming increasingly narrow in order to increase the density of inkjet heads. For example, the nozzle-to-nozzle spacing at a nozzle density of 180 dpi (dpi in the present invention represents the number of dots per 2.54 cm) is 140 μm. In this case, if a 70 μm pressure chamber partition wall exists between 140 μm, the width of the pressure chamber is 70 μm. If the nozzle extends from the outer surface toward the pressure chamber side and the inner diameter on the pressure chamber side is 40 μm, the distance from the end of the partition wall to the nozzle is only 15 μm. When the nozzle plate is bonded to the recording element substrate, flow path member, etc., if heat treatment is performed to cure the adhesive, the viscosity of the adhesive will decrease due to this heating operation, so it will flow easily. Will flow into the nozzle part, and part of the nozzle part or, in the worst case, will block the entire region. In particular, when the applied ink has a property of swelling or dissolving the adhesive, the ink resistance of the adhesive must be improved. For this purpose, it is effective to increase the glass transition point of the adhesive by heating it at a high temperature when curing the adhesive, but when the adhesive is heated to a high temperature, the viscosity tends to decrease and the nozzle part tends to be blocked. Increases more.

  From the viewpoint of preventing the adhesive from flowing into the nozzle area, if the amount of adhesive applied is reduced, the surface of the flow path member may be uneven or dust may adhere to the nozzle plate. An air gap without adhesive is generated between the path members, and the ink may leak through the gap. On the other hand, if the amount of adhesive applied is increased, the amount of adhesive that protrudes from the gap between the members increases, and the adhesive flows into the nozzle region. This eliminates the gap and eliminates the flow into the nozzle. It was difficult.

  As a method for preventing the overflowing adhesive from flowing in, for example, the recording element substrate and the support substrate are bonded with an adhesive having both UV curable properties and heat curable properties, and the protruding adhesive is irradiated with ultraviolet rays. A method is disclosed in which an ink jet recording head is manufactured by performing next curing and then heat treatment (see Patent Document 1). As a result, it was possible to prevent the overflowing adhesive from flowing in, but it was difficult for the adhesive to cure due to thermal curing, and the durability against solvent ink was particularly low. In particular, an epoxy resin containing both a cationic photopolymerization initiator and a thermal cationic polymerization initiator has an effect of inhibiting thermal polymerization by the cationic photopolymerization initiator, and the thermal polymerization does not proceed sufficiently with the method of Patent Document 1. In general, even if the durability against water-based ink is sufficient, the durability against solvent ink, which is one of the purposes of the present application, is often not satisfactory, and the optimum material is selected and cured to improve the degree of crosslinking. And cannot be achieved.

JP 2007-15238 A

  The object of the present invention is that there is no gap in the adhesive at the part where the members are joined, the adhesive does not flow into unnecessary parts, the bonding property is good, the adhesive force is large, the water resistance as well as the solvent resistance It is an object of the present invention to provide a method for manufacturing an ink jet head with good quality.

  The above object of the present invention is achieved by the following configurations.

  1. An inkjet head having a heating step after a step of bonding a plurality of members with an adhesive containing an epoxy resin, a photocationic polymerization initiator, and a thermal cationic polymerization initiator, and a step of irradiating light to the protruding portion of the adhesive In the manufacturing method, 80 to 100% by mass of the epoxy resin is an aromatic epoxy compound, and the heating step includes a step of raising the temperature in a temperature range of 40 ° C to 150 ° C.

  2. 2. The method of manufacturing an ink-jet head as described in 1 above, wherein the heating step includes a step of raising the temperature at a rate of temperature rise of 0.1 ° C. to 2 ° C. per minute.

  3. 2. The method of manufacturing an ink jet head according to 1, wherein the heating step is performed by combining two or more isothermal processes.

  4). The method for manufacturing an ink jet head according to any one of 1 to 3, wherein the thermal cationic polymerization initiator includes a complex compound represented by the following general formula (I).

  R represents a hydrogen atom or an alkyl group.

R ₁ , R ₂ and R _{3 each} represents a hydrogen atom, an alkyl group, an alkoxy group, an aryloxy group or a halogen atom.

  5. The said epoxy resin contains 1-50 mass% of novolak epoxy resins, The manufacturing method of the inkjet head of any one of said 1-4 characterized by the above-mentioned.

  6). 6. The method of manufacturing an ink jet head according to any one of 1 to 5, wherein the member is obtained by plasma-irradiating at least a joint portion.

  7). 6. The method of manufacturing an ink jet head according to any one of 1 to 5, wherein the member is obtained by treating at least a joint portion with an acid.

  According to the present invention, there is no emission failure due to the adhesive flowing into the flow path, the bonding property is good, the ink does not leak from the ink flow path due to the peeling of the member and the adhesive, and it is durable against solvent ink It was possible to provide a method for manufacturing an inkjet head having excellent properties.

FIG. 2 is an exploded perspective view illustrating an example of the configuration of the inkjet recording head of the present invention. It is a rear view which shows an example of the rear surface of the head chip of the inkjet recording head of this invention. It is sectional drawing which shows an example of the state which adhered the nozzle plate and the pressure chamber formed in the head chip with the adhesive agent.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail, but the present invention is not limited thereto.

  As a result of intensive studies in view of the above problems, the present inventor bonded a plurality of members with an adhesive containing an epoxy resin, a cationic photopolymerization initiator, and a thermal cationic polymerization initiator, and the portion where the adhesive protruded In the manufacturing method of the inkjet head which has a heating process after irradiating light, 80-100 mass% of the said epoxy resin is an aromatic epoxy compound, and a heating process heats up in the temperature range of 40 to 150 degreeC. The inkjet head manufacturing method is characterized by having an ejection failure due to the adhesive flowing into the flow path, the ink does not leak from the ink flow path, and has excellent durability against solvent ink It has been found that a recording head can be realized and has reached the present invention.

  Hereinafter, the details of the inkjet recording head of the present invention and the inkjet ink applied to inkjet image recording will be described.

(Inkjet recording head)
First, a basic configuration example of the ink jet recording head of the present invention will be described with reference to the drawings.

  FIG. 1 is an exploded perspective view showing an example of an ink jet recording head, and FIG. 2 is a rear view showing a rear surface of a head chip.

  In FIG. 1, 1 is a head chip, 2 is a nozzle plate bonded to the front surface of the head chip 1, and 3 is a wiring substrate bonded to the rear surface of the head chip 1.

  In the present specification, the surface on the side where the liquid that hits the nozzle of the head chip 1 is discharged is referred to as “front surface”, and the opposite surface is referred to as “rear surface”. The head chip 1 corresponds to a flow path member according to the present invention. In FIG. 1, the ink flow direction is from bottom to top.

  The head chip 1 referred to in the present invention includes, for example, a flow path member 11 made of a piezoelectric material and pressure chambers (ink supply paths) 12 arranged alternately in parallel. The shape of the pressure chamber 12 is such that both side walls are formed parallel to each other. An outlet and an inlet of each pressure chamber 12 are arranged on the front surface and the rear surface of the head chip 1, respectively, and each pressure chamber 12 is a straight type whose size and shape are not substantially changed in the length direction from the inlet to the outlet.

  In the head chip 1, each pressure chamber 12 has two pressure chamber rows. Each pressure chamber row includes eight pressure chambers 12, but the number of pressure chambers 12 constituting the pressure chamber row in the head chip 1 is not limited at all.

  The head chip 1 is formed by bonding a piezoelectric body 101 having a plurality of grooves and a lid member 102. On the surface of the groove of the piezoelectric body 101, a drive electrode made of a metal layer M indicated by hatching in FIG. 1 is formed.

  The metal layer M is preferably covered with a transparent insulating layer for the purpose of preventing corrosion due to ink.

  On the rear surface of the head chip 1, connection electrodes 14 (voltage application electrodes) drawn from the metal layer M of each pressure chamber 12 are formed. The connection electrode 14 can be formed by vapor deposition or sputtering.

  The nozzle plate 2 is provided with nozzles 21 at positions corresponding to the outlets of the pressure chambers 12 of the head chip 1, and is bonded to the front surface of the head chip 1 on which the connection electrodes 14 are formed using an adhesive. . Therefore, the inlet and outlet of each pressure chamber 12 and the nozzle 21 are linearly arranged.

  The wiring board 3 is a plate-like member for connecting a wiring for applying a driving voltage from a driving circuit (not shown) to each metal layer M of the head chip 1. The substrate used for the wiring substrate 3 is a substrate made of a ceramic material such as non-polarized PZT, AlN-BN, or AlN, a substrate made of low thermal expansion plastic or glass, or a piezoelectric material used in the head chip 1. A substrate obtained by depolarizing the same substrate material as the substrate material can be used. Preferably, in order to suppress the occurrence of distortion or the like of the head chip 1 due to the difference in thermal expansion coefficient, a material having a difference in thermal expansion coefficient within ± 3 ppm with respect to unpolarized PZT is selected.

  The substrate constituting the wiring substrate 3 is not limited to a single plate, and a plurality of thin plate materials may be laminated to form a desired thickness.

  The wiring substrate 3 has a larger area than the rear surface of the head chip 1 and extends in a direction (B direction in the drawing) orthogonal to the direction in which the pressure chambers 12 of the head chip 1 are arranged (pressure chamber row direction). Each of the protruding ends is a wiring electrode 33 for connecting an FPC (not shown). In addition, the wiring board 3 also protrudes greatly in the direction in which the pressure chambers 12 of the head chip 1 are arranged (direction A in the figure).

  An opening 32 is formed through the substantially central portion of the wiring board 3. The opening 32 is formed in such a size that the opening on the inlet side of the total pressure chamber 12 facing the rear surface of the head chip 1 can be exposed.

  As a method for forming the opening 32, depending on the substrate material, a method of processing with a dicing saw, a method of processing with an ultrasonic processing machine, a method of molding and firing ceramics before sintering, a method of forming by sand blasting Etc. can be adopted.

  Wiring electrodes 33 (voltage application electrodes) are formed on the surface of the wiring board 3 on the bonding surface side with the head chip 1 with the same number and pitch (W1 + W2) as the connection electrodes 14 formed on the rear surface of the head chip 1. Then, it extends from the peripheral edge of the opening 32 to each wiring connection portion 31, 31 and reaches the outer edge of the wiring board 3. The wiring electrode 33 is electrically connected to each wiring formed in the FPC or the like when the FPC or the like is joined, and a drive voltage from the drive circuit is applied to the metal layer in the pressure chamber 12 via the connection electrode 14. It functions as an electrode for applying to M.

  In addition to the wiring electrodes 33, a positioning pattern 38 for positioning the head chip 1 is formed on the surface of the wiring substrate 3. The positioning pattern 38 is fitted with a positioning pattern 39 formed on the rear surface of the head chip 1 at the time of joining to the head chip 1 and used when positioning the head chip 1.

  After the head chip 1 and the wiring board 3 formed in this way are coated with adhesives on their bonding surfaces, as shown in FIG. 1, the connection electrodes 14 of the head chip 1 and the wiring board 3 are connected to each other. The wiring electrodes 33 are aligned and overlapped so as to be electrically connected, and the adhesive is cured by heating and pressing at a predetermined temperature and a predetermined time.

  Further, the nozzle plate 2 on which the nozzles 21 are formed is bonded to the front surface of the head chip 1 with an adhesive. Thereby, an ink jet recording head is obtained.

  As described above, the adhesive according to the present invention can be applied to the bonding of the nozzle plate and the wiring board, the bonding of the manifold, and the like to the head chip.

  FIG. 3 is a cross-sectional view showing an example of a state in which the nozzle plate and the head chip are bonded with an adhesive.

  The manufacturing method of the ink jet recording head of the present invention will be described with reference to FIG.

1) Step of Joining Flow Channel Member and Nozzle Plate FIG. 3 shows the bonding of the head chip 1 in the ink jet recording head shown in FIG. 1 and the nozzle plate 2 joined to the front surface of the head chip 1 according to the present invention. The state joined by the agent is shown.

  First, on the surface of the head chip 1 to which the nozzle plate is bonded, the epoxy resin according to the present invention, a cationic photopolymerization initiator, and a thermal cationic polymerization agent are used. Use to give desired amount. The amount of adhesive applied is not particularly limited, but the wet film thickness when applied is preferably 2.0 μm or more and 8.0 μm or less. If the applied amount of the adhesive is 2.0 μm or more, an adhesive non-existing area is not formed between the head chip 1 and the nozzle plate 2 and a uniform adhesive surface can be formed. Leakage and adhesion failure can be prevented. Moreover, if it is 8.0 micrometers or less, the application amount of an adhesive agent will not become excessive, an adhesive overflow etc. can be prevented and the ooze to a nozzle area | region can be prevented.

  The amount of adhesive applied is determined by subtracting the mass of the chip from the mass of the chip to which the adhesive has been applied, and dividing it by the specific gravity of the adhesive to obtain the capacity of the adhesive. It is calculated by dividing by.

  The flow path member 11 may be made of any material, and examples thereof include a piezoelectric material and silicon. In the present invention, the ink supply path including the flow path member is a piezoelectric body (piezoelectricity). It is preferable that it is comprised from ceramics.

  As the piezoelectric ceramic constituting the flow path member, any conventionally known piezoelectric ceramics can be used. However, ceramics such as PZT and PLZT are mainly used for mixed microcrystals of PbOx, ZrOx, TiOx, softening agents or hard A trace amount of a metal oxide known as an agent, for example, an oxide containing Nb, Zn, Mg, Sn, Ni, La, Cr or the like is preferable.

  PZT is lead zirconate titanate, which is preferable because it has a high packing density, a large piezoelectric constant, and good workability. When the temperature is lowered after firing, the crystal structure suddenly changes, and PZT becomes a collection of fine crystals in the form of dipoles in which atoms are displaced, one side is positive, and the other side is negative. These spontaneous polarizations are random in direction and cancel each other's polarity, so further polarization processing is required.

  In the polarization treatment, a thin plate of PZT is sandwiched between electrodes, immersed in silicon oil, and polarized by applying a high electric field of about 10 to 35 kV / cm. The piezoelectricity due to this polarization treatment generally disappears in PZT when a temperature higher than this is applied with a temperature around 200 ° C. as the Curie point.

In the present invention, it is preferable that at least one of the bonding surfaces of the head chip 1 and the nozzle plate 2 is subjected to acid treatment, plasma treatment or UV treatment. In the plasma treatment, a nozzle plate, a head chip and the like are placed in a vacuum chamber, and at least one selected from Ar, N ₂ and O ₂ or a mixed gas thereof is injected, and a plasma state is generated by an external electromagnetic field. Fluorine hydrocarbon gas such as CF ₄ may be used in order to improve the surface etching property. The acid treatment can be performed by immersing the adhesive surface in an aqueous solution such as hydrochloric acid. Further, the UV treatment is a treatment for directly irradiating the nozzle plate or the flow path member with an ultraviolet light emitting lamp, and may be in an O ₂ atmosphere in order to obtain a cleaning effect with ozone. By performing plasma treatment, acid treatment, and UV treatment on the adhesive surface in this way, organic contaminants can be washed away, improving the wettability of the adhesive to the entire adhesive surface, and eliminating poor adhesion such as minute foam residue. Thus, ink leakage and poor adhesion can be eliminated, and a stable inkjet recording head can be manufactured.

  In the piezoelectric body 101, for example, a minute groove (for example, length: 3 mm, height: 360 μm, width: 70 μm) is processed on one surface of a substrate having a thickness of 1 mm. By bonding (adhering) the lid member 102 to the processed surface of the substrate, a pressure chamber (length: 3 mm mm, height: 360 μm, width: 70 μm) serving as an ink flow path is formed in the groove. One end of the pressure chamber is connected to the ink storage unit via a manifold including a wiring board and a filter unit, and the other end is connected to an ink discharge port (nozzle plate).

  In the present invention, the flow path member 11 forming the ink chamber preferably has a metal layer M on the ink supply path surface side.

  The metal layer M may act as a drive electrode for the flow path member (piezoelectric body). The metal forming the metal layer includes Ni, Co, Cu, Al, Sn, Cr, etc., and Al or Cu is preferably used from the viewpoint of electrical resistance, but Ni is preferable from the viewpoint of corrosion, strength, and cost. Used. Alternatively, a laminated structure in which Au is further laminated on Al may be employed.

  Examples of the formation of the metal layer M include a method of forming a metal film by a method using a vacuum apparatus such as a vapor deposition method, a sputtering method, a plating method, and a CVD (chemical vapor reaction method). It is particularly preferable to form by electroless plating. By electroless plating, a uniform and pinhole-free metal coating can be formed. The thickness of the plating film is preferably in the range of 0.5 to 5 μm.

  As the nozzle plate material, a material that can be ablated by laser light or a material that can be anisotropically etched is used. For example, a resin sheet such as polyimide, polyethylene terephthalate, polyamide, polysulfone, or silicon is preferably used. However, it is particularly preferable to be made of polyimide that can withstand the high temperature applied when the ink-repellent layer is provided on the surface and can be precisely nozzle-processed by a laser.

2) Step of curing by irradiating light from the ink supply side of the flow path member In the above step, after the nozzle plate 2 and the chip 1 are bonded with the adhesive 15, the adhesive is irradiated with light energy. The first curing process is performed.

  In the present invention, when the adhesive is cured by light irradiation, the surface of the ink supply path 12 for light irradiation is preferably formed of the metal layer M. By configuring the ink supply path 12 having such a metal surface, as shown in FIG. 3, the light was irradiated when irradiated from the irradiation light source from the direction indicated by the arrow A on the ink supply side. The light reflected by the metal surface and attenuated until reaching the adhesive layer 15 located deeply is small, and light energy required for curing can be supplied.

  The irradiation light source used for curing the adhesive is preferably a light source including an ultraviolet lamp that emits ultraviolet light in a specific wavelength region with stable exposure energy and a filter that transmits ultraviolet light of a specific wavelength. As the ultraviolet lamp, a mercury lamp, a metal halide lamp, an excimer laser, an ultraviolet laser, a cold cathode tube, a hot cathode tube, a black light, an LED (light emitting diode), and the like are applicable, and in particular, a high pressure that emits ultraviolet light having a wavelength of 365 nm. A mercury lamp is preferred.

3) Step of curing the adhesive by performing heat treatment In the step 2), after the primary curing of the adhesive layer 15 is performed by light irradiation, thermal energy is applied to provide stronger adhesion. A secondary curing process is performed to cure the portion that was not exposed to light and to form an agent layer. By performing this heating step, the adhesive can reach the target solvent resistance.

  In the case of adhesion of the nozzle plate, the inkjet head moves relative to the non-recording medium while maintaining a narrow gap with the recording medium. If the non-recording medium has irregularities such as waviness, the nozzle plate may come into contact with the recording medium when the inkjet head moves. In particular, when the ink jet head is used for a long time and the used adhesive is swollen by the solvent of the ink, the nozzle plate may be peeled off by such contact. In order to improve such problems, it is effective to increase the adhesive force and to reduce the swelling of the adhesive when immersed in a solvent ink for a long period of time.

  The heating temperature for curing the adhesive is appropriately selected depending on the type of the adhesive and in a range that does not affect the constituent members of the ink jet recording head, but the maximum temperature in the heating step is from 60 ° C. to 150 ° C. It is in the range of ° C.

  The present invention includes a step of raising the temperature in the temperature range of 40 ° C. to 150 ° C. during the heating step. For example, when the head is put into an oven and cured by heating, the temperature rise means that the temperature of the oven is measured and the temperature of the oven is raised halfway. Examples of the method of increasing the temperature include a method of increasing the temperature at a constant rate, and a method of increasing the temperature stepwise, such as heating at a certain constant temperature and then heating at a higher constant temperature. For example, when the head is put into an oven at 25 ° C., the temperature is increased at a rate of 1 ° C. per minute, and when the temperature is increased to 100 ° C., 40 ° C. is passed on the way and the temperature further increases, so the temperature of the present invention is increased. Process. In addition, if the head is put into an oven at 50 ° C. for 1 hour and then moved to an oven at 100 ° C. for 1 hour, the temperature is raised by passing through two isothermal processes with different temperatures. Can do.

  When the temperature is increased at a constant rate, the rate is preferably 0.1 ° C. to 2 ° C. per minute because the solvent resistance of the adhesive is increased. When the temperature is raised by combining two or more isothermal processes, the low temperature side is preferably 40 to 80 ° C. and the high temperature side is 60 to 120 ° C. in order to obtain high solvent resistance and water resistance. The heating time is preferably 30 minutes to 4 hours on the low temperature side, and preferably 30 minutes to 4 hours on the high temperature side.

  As the means for applying thermal energy, a heating tool that can be heated by pressure bonding to an electric oven or an ink jet recording head is preferable, and examples thereof include a hot plate and a ribbon heater. In addition, as a means for cooling at least the piezoelectric body portion during the heat treatment, it is preferable to use a means for circulating cold water through the aluminum block for cooling. In the present invention, the temperature of the heating step is difficult to measure the temperature of the adhesive itself. Instead, the temperature of an oven or a pressure tool is measured and used instead.

"adhesive"
The adhesive applied when producing the ink jet recording head of the present invention contains a thermal cationic polymerization initiator together with an epoxy compound and a cationic photopolymerization initiator, and 80 to 100% by mass of the total epoxy resin is an aromatic epoxy compound. It is characterized by being.

(Thermal cationic polymerization initiator)
The thermal cationic polymerization initiator according to the present invention is a cationic thermal polymerization initiator for thermally polymerizing an epoxy monomer, and a boron trifluoride amine complex, a sulfonium salt, an aluminum complex, or the like is used. Of these, boron trifluoride amine complex is preferable, and the compound of general formula (1) is particularly preferable in that an adhesive cured product having high solvent resistance can be obtained.

In the general formula (I), R represents a hydrogen atom or an alkyl group, preferably a hydrogen atom. R ₁ , R ₂ and R ₃ each represents a hydrogen atom, an alkyl group, an alkoxy group, an aryloxy group or a halogen atom.

Examples of the alkyl group represented by R and R _{1 to} R ₃ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group, an isobutyl group, a sec-butyl group, a pentyl group, and a tert group. -Pentyl group, hexyl group, 2-methylpentyl group, isohexyl group, heptyl group, isoheptyl group, 1-propylbutyl group, octyl group, 2-ethylhexyl group, isooctyl group, nonyl group, isononyl group, decyl group, isodecyl group , Undecyl group, dodecyl group and the like.

Examples of the alkoxy group represented by R _{1 to} R ₃ include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group. Examples of the group include a phenoxy group and a naphthyloxy group. Moreover, as a halogen atom, a chlorine atom, a bromine atom, a fluorine atom, etc. can be mentioned.

  Next, specific examples of the thermal cationic polymerization initiator represented by the general formula (I) according to the present invention will be shown, but the present invention is not limited only to these exemplified compounds.

  Preferable thermal cationic polymerization initiators according to the present invention include complex compounds of aniline derivatives listed below and boron trifluoride.

<Aniline derivative>
Compound 1: 2-chloroaniline Compound 2: 3-chloroaniline Compound 3: 4-chloroaniline Compound 4: 3-chloro-4-fluoroaniline Compound 5: 2,5-dimethylaniline Compound 6: 3,4-dimethoxyaniline Compound 7: 2-ethylaniline Compound 8: 4-ethylaniline Compound 9: N-ethylaniline Compound 10: 3,4-dichloroaniline Compound 11: 3,5-dichloroaniline Compound 12: 3-fluoroaniline Compound 13: 4 -Fluoroaniline Compound 14: 2-Fluoro-4-methylaniline Compound 15: 4-Fluoro-3-methylaniline Compound 16: 4-Methoxy-2-methylaniline Compound 17: 3,4-difluoroaniline Compound 18: 4- Butylaniline Compound 19: N-methylaniline Compound 2 0: 2,4,6-Tribromoaniline Compound 21: 2,3,4-trifluoroaniline Compound 22: 2,3,6-trifluoroaniline Compound 23: 2,4,6-trifluoroaniline Compound 24: 2,3,4-trifluoroaniline Compound 25: 2,4,6-trimethylaniline Compound 26: 2,4,5-trimethylaniline Compound 27: N-benzylaniline Compound 28: 4-chloroaniline Compound 29: 2- Chloroaniline Compound 30: 4,4′-methylenebisaniline Compound 31: 3-phenoxyaniline Compound 32: 4-butoxyaniline Compound 33: 4-butoxyaniline Compound 34: 3,4-dimethoxyaniline Compound 35: Aniline The thermal cationic polymerization initiator represented by the general formula (I) is known by those skilled in the art. It can be synthesized according to the synthetic method. A complex of aniline and boron trifluoride of Compound 35 is commercially available as a polyethylene glycol solution from PTI Japan under the trade name BAK1171.

  Moreover, it is preferable to add 0.1-30 mass% in the thermal cationic polymerization initiator represented by general formula (I) in solid content of an adhesive agent, More preferably, it is 0.5-5 mass%. .

(Epoxy resin)
As an epoxy compound applicable to the adhesive according to the present invention, any of a monomer of an epoxy group-containing compound and an oligomer thereof can be used. Specific examples include conventionally known aromatic epoxy compounds, alicyclic epoxy compounds, and aliphatic epoxy compounds. Hereinafter, the epoxy compound means a monomer or an oligomer thereof.

  In the present invention, an aromatic epoxy monomer is used in an amount of 80% by mass or more based on the epoxy monomer as the epoxy monomer.

  A preferable aromatic epoxy compound is a di- or polyglycidyl ether produced by the reaction of a polyhydric phenol having at least one aromatic nucleus or an alkylene oxide adduct thereof and epichlorohydrin, for example, bisphenol A or its Examples thereof include di- or polyglycidyl ethers of alkylene oxide adducts, hydrogenated bisphenol A or di- or polyglycidyl ethers of alkylene oxide adducts thereof, bisphenol F type epoxy resins, and novolak type epoxy resins. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.

  As the alicyclic epoxy compound, cyclohexene oxide or cyclopentene obtained by epoxidizing a compound having at least one cycloalkane ring such as cyclohexene or cyclopentene ring with an appropriate oxidizing agent such as hydrogen peroxide or peracid. An oxide containing compound is mentioned. Specific examples include (3,4-epoxycyclohexyl) methyl-3,4-epoxycyclohexylcarboxylate, bis- (2,3-epoxycyclopentyl) ether, and the like.

  In the present invention, the epoxy monomer is preferably a novolak-type epoxy compound, a bisphenol A-type epoxy compound, a bisphenol F-type epoxy compound, or the like. It is preferable in terms of good properties.

(Photopolymerization initiator)
In the present invention, any known photoacid generator can be used as a photocationic polymerization initiator (photopolymerization initiator) for photopolymerizing a cationically polymerizable monomer. As the photoacid generator, for example, a chemically amplified photoresist or a compound used for photocationic polymerization is used (edited by Organic Electronics Materials Research Group, “Organic Materials for Imaging”, Bunshin Publishing (1993), 187. To page 192).

First, diazonium, ammonium, iodonium, sulfonium, aromatic onium compounds such as phosphonium ^{_{B (C 6 F 5) 4}} -, PF 6 -, AsF 6 -, SbF 6 -, CF 3 SO 3 - and salts Secondly, sulfonates that generate sulfonic acid can be mentioned, thirdly, halides that generate hydrogen halide can also be used, and fourthly, iron allene complexes can be mentioned. Examples include hexafluorophosphate, hexafluoroantimonate or pentafluorophenyl borate salt of diallyl iodonium or triallyl sulfonium, Irgacure-261 (manufactured by Ciba Geigy), SP-150, SP-170 (above, Asahi Denka Co., Ltd.) ), PI2074, and UVI-6992 (manufactured by Dow Chemical).

<Inkjet ink>
The ink-jet ink applicable when forming an image using the ink-jet recording apparatus equipped with the ink-jet recording head of the present invention is not particularly limited, and is a water-based ink-jet ink, a non-aqueous ink-jet ink, a wax ink, or an active curable ink-jet ink. Among them, from the viewpoint that the excellent characteristics of the ink jet recording head of the present invention can be exhibited, an ink jet ink having an organic solvent content of 50% or more of the total solvent, and further a resin component It is preferable to apply the organic solvent having a solubility parameter (SP value) having a high solubility to 16.0 to 21.0 to image formation using an inkjet ink containing 30% by mass or more of the total organic solvent.

(Organic solvent)
In recent years, an example of using an inkjet recording method for various applications (for example, outdoor signboards and electronic component manufacturing) has increased. For example, for an outdoor signboard, an inkjet ink containing a solvent that dissolves vinyl chloride, which is a material of the image receiving sheet, is used. In order to dissolve various compounds in the production of electronic parts, a solvent having a high solubility in the resin is used for the inkjet ink. Even when such a resin-soluble solvent is used, it is necessary to maintain strength as an ink jet recording head.

  The ink jet recording apparatus according to the present invention is preferably compatible with an ink jet ink in which 50% or more and 100% or less of the total solvent is composed of an organic solvent.

The solubility parameter (SP value) of the organic solvent referred to in the present invention is a value represented by the square root of the molecular aggregation energy. F. It can be calculated by the method described in Fedors, Polymer Engineering Science, 14, p147 (1974). The unit is (MPa) ^1/2 and indicates a value at 25 ° C. Examples of the organic solvent having an SP value defined in the present invention include J.P. Brandup, E .; H. Also described in Immersu, “Polymer Handbook” 3rd edition (John Wily & Sons) 1989, VII / 526-539.

Examples of organic solvents having a solubility parameter (SP value) of 16.0 (MPa) ^1/2 or more and 21.0 (MPa) ^1/2 or less are shown below, but are not limited to these exemplified compounds. . In addition, the numerical value in a parenthesis represents SP value ((MPa) ^1/2 .

  Amyl acetate (16.0), ethylene glycol diethyl ether (17.0), ethyl propionate (17.2), diethylene glycol monoethyl ether acetate (17.4), methyl-2-pentanediol monoethyl ether (17 .4), ethylene glycol dimethyl ether (17.6), diethylene glycol monolaurate (17.8), ethylene glycol monoethyl ether acetate (17.8), tripropylene glycol methyl ether (17.8), butyl propionate (18.0), ethyl acetate (18.6), ethylene glycol methyl ethyl acetate (18.8), tripropylene glycol (18.8), dipropylene glycol monomethyl ether (19.0), ethyl-2-he Sundiol-1,3 (octylene glycol) (19.2), butyl lactate (19.2), diethylene glycol monobutyl ether (19.4), ethylene glycol monobutyl ether (19.4), cyclohexanone (20.3) Ethyl lactate (20.5), anisole (19.4) and the like.

(Other ink additives)
The inkjet ink according to the present invention may contain various additives in addition to the organic solvent.

  The ink according to the present invention can contain a color material. As the color material, for example, a color material that forms yellow, magenta, cyan, black, blue, green, or red ink is preferably used.

  In the ink according to the present invention, a dye ink whose color material is a dye, or a pigment ink or a color material that forms a dispersion containing fine pigment particles that is insoluble in a solvent constituting the ink-jet ink. The present invention can be applied to various ink-jet inks such as a dispersion ink made of a polymer dispersion.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

<Production of inkjet recording head>
Example 1: [Preparation of Inkjet Recording Head 1]
(Preparation of head chip)
A head chip having the configuration shown in FIGS. 1 to 3 was produced according to the following method.

  PZT (lead zirconate titanate, thickness 700 μm, Curie temperature 210 ° C.) and PZT (thickness 150 μm, Curie temperature 210 ° C.) were bonded using an adhesive so that the polarization directions were opposite. Next, after a resist layer is formed by transferring a resist layer to the front and back surfaces of PZT having a thickness of 150 μm, a groove having a depth of 300 μm and a width of 70 μm is cut from the surface to a length of 30 mm at a pitch of 140 μm to form a pressure chamber groove. did. Next, a nickel layer having a thickness of 1 μm was formed on the surface of the groove by plating, and then the resist on the top of the pressure chamber wall and the resist on the back surface were peeled off together with the nickel plating layer on the resist.

  A cover plate (depolarized PZT having a thickness of 700 μm) was joined to the surface from which the resist at the top of the pressure chamber was removed to form a chip having a plurality of ink flow paths. The two chips were bonded so that the ink flow paths were parallel to each other so that the cover plate was on the outside, thereby forming a chip having two flow paths. Next, cutting was performed at intervals of 2 mm along a direction perpendicular to the direction of the flow path to form a plurality of head chips with L = 2 mm.

  In the chip manufactured in this way, drive walls and flow paths made of piezoelectric elements are alternately arranged in parallel.

  In order to be able to connect FPC (Flexible Printed Circuits) for applying a drive voltage from the drive circuit to the drive electrodes in each flow path, each drive electrode was drawn out to the outer surface of the chip. That is, after a resist was transferred to the rear surface of the cut surface and a pattern was formed by exposure and development, aluminum was deposited and the resist was removed to form a lead electrode.

  Although not shown in FIGS. 1 to 3, the wiring board is provided as a plate-like member for connecting a wiring for applying a driving voltage from a driving circuit to each driving electrode of the head chip. The substrate used for this wiring board was selected so that the difference in thermal expansion coefficient with the head chip was within ± 1 ppm in order to suppress the occurrence of distortion of the head chip due to the difference in thermal expansion coefficient.

  In addition, an opening was formed through substantially the center of the wiring board. This opening was formed with a size that could expose the inlet side of all channels of the head chip. By providing this opening, it is possible to look through all the driving walls, all the channels and all the driving electrodes of the head chip through this opening while the wiring substrate is bonded to the rear surface of the head chip.

  In addition, wiring electrodes are formed on the surface of the wiring board on the bonding surface side with the head chip at the same number and pitch as the connection electrodes formed on the rear surface of the head chip, and extend to the wiring connection portions. This wiring electrode is electrically connected to each wiring formed in the FPC when the FPC is joined, and the driving voltage supplied from the driving circuit via the FPC wiring is supplied to the channel via the connection electrode. It functions as an electrode for applying to the drive electrode.

  The wiring board is aligned and bonded to the back surface of the chip with an anisotropic conductive adhesive so that each wiring electrode is electrically connected to each connection electrode of the chip and the opening exposes the entire flow path of the chip. did. Later, electrodes for FPC bonding were protected with a masking tape, and a protective film made of polyparaxylylene was formed on the pressure chamber surface including the drive electrode and the exposed portion of the cross section including the extraction electrode.

(Adhesion of nozzle plate)
The following adhesive A was transferred and applied to the front surface of the produced head chip with a thickness of 5 μm. Next, while observing with an optical microscope, a nozzle plate (100 μm thick polyimide formed with a 30 μm diameter nozzle hole) was joined to a predetermined position on the surface of the head chip coated with the adhesive. Next, a high pressure mercury lamp was irradiated from the rear surface of the head chip at an irradiation amount of 5000 mJ / cm ² at room temperature, and then the adhesive A was cured under the following curing condition 1.

(Adhesive A)
Epicoat 807 (Bisphenol F type epoxy resin; made by Japan Epoxy Resin)
10g
UVI6992 (photo cationic polymerization initiator; manufactured by Dow Chemical) 0.4 g
Boron trifluoride aniline complex solution (40 mass% 4-butyrolactone solution) 0.5 g
(Curing condition 1)
An ink jet recording head is put into an oven having an initial temperature of 25 ° C., the temperature of the oven is increased from 25 ° C. at a rate of 1 ° C. per minute, and after reaching 100 ° C. and heated at a constant temperature for 1 hour, the ink jet head Remove from the oven.

Example 2: [Preparation of inkjet recording head 2]
In the production of the inkjet recording head 1, the inkjet recording head 2 was produced in the same manner except that the heating was performed under the following curing condition 2 instead of heating under the curing condition 1.

(Curing condition 2)
The ink jet recording head is put into an oven having an initial temperature of 50 ° C., and the oven temperature is kept at 50 ° C. for 2 hours. After that, the oven temperature setting is changed and the oven temperature reaches 100 ° C. After heating for a period of time, the inkjet head is removed from the oven.

Example 3: [Preparation of inkjet recording head 3]
In the production of the inkjet recording head 1, the inkjet recording head 3 was produced in the same manner except that the adhesive B used below was used instead of the adhesive A instead of the adhesive A.

(Adhesive B)
Epicoat 807 (Bisphenol F type epoxy resin; made by Japan Epoxy Resin)
6g
Epicoat 152 (phenol novolac epoxy resin; made by Japan Epoxy Resin)
4g
UVI6992 (photo cationic polymerization initiator; manufactured by Dow Chemical) 0.4 g
Boron trifluoride aniline complex solution (40 mass% 4-butyrolactone solution) 0.5 g
Example 4: [Preparation of inkjet recording head 4]
In the production of the ink jet recording head 1, the adhesive used for adhering the nozzle plate is replaced with the adhesive A, the following adhesive B is used, and the heating is performed under the curing condition 1 instead of being heated under the curing condition 1. An inkjet recording head 4 was produced in the same manner except that.

Example 5: [Production of inkjet recording head 5]
In the production of the inkjet recording head 1, the inkjet recording head 5 was produced in the same manner except that the adhesive C used below was used instead of the adhesive A instead of the adhesive A.

(Adhesive C)
Epicoat 807 (Bisphenol F type epoxy resin; made by Japan Epoxy Resin)
9g
Celoxide 2012 (alicyclic epoxy resin; manufactured by Daicel UCB) 1 g
UVI6992 (photo cationic polymerization initiator; manufactured by Dow Chemical) 0.4 g
Boron trifluoride aniline complex solution (40 mass% 4-butyrolactone solution) 0.5 g
Comparative Example 1: [Production of Inkjet Recording Head 6]
In the production of the ink jet recording head 1, the adhesive described in Example 1 of Patent Document 1 is used instead of the adhesive A instead of the adhesive used for adhering the nozzle plate, and heating is performed under the curing condition 1. Instead, the inkjet recording head 6 was produced in the same manner except that the heating was performed under the following curing condition 3.

(Curing condition 3)
The ink jet recording head is put into an oven at 100 ° C. and taken out from the oven after 3 hours.

Comparative Example 2: [Production of Inkjet Recording Head 7]
In the production of the inkjet recording head 1, an inkjet recording head 7 was produced in the same manner except that heating was performed under the curing condition 3 instead of heating under the curing condition 1.

Comparative Example 3: [Production of Inkjet Recording Head 8]
In the production of the ink jet recording head 1, instead of the adhesive A, the following adhesive E is applied to the front surface of the head chip, and after irradiating the front surface of the head chip with a high-pressure mercury lamp at 200 mJ / cm ² , the nozzle plate is bonded. The inkjet recording head 8 was produced in the same manner except that the heating was performed under the curing condition 3.

<Adhesive E>
Epicoat 807 (Bisphenol F type epoxy resin; made by Japan Epoxy Resin)
10g
Adekaoptomer SP-170 (Photocationic polymerization initiator; manufactured by ADEKA) 0.2 g
Boron trifluoride aniline (25% by weight diethylene glycol solution) 0.8 g
Comparative Example 4: [Production of Inkjet Recording Head 9]
In the production of the ink jet recording head 1, the following adhesive F was prepared instead of the adhesive A as an adhesive to be transferred and applied to the front surface of the head chip. The fluidity of the adhesive disappeared, and an attempt was made to paste the nozzle plate. However, since the adhesive did not adhere, the ink jet recording head 9 of the head chip could not be produced.

(Adhesive F)
Epicoat 807 (Bisphenol F type epoxy resin; made by Japan Epoxy Resin)
7g
Celoxide 2012 (alicyclic epoxy resin; manufactured by Daicel UCB) 3g
UVI6992 (photo cationic polymerization initiator; manufactured by Dow Chemical) 0.4 g
Boron trifluoride aniline complex solution (40 mass% 4-butyrolactone solution) 0.5 g
Example 6: [Production of inkjet recording head 10]
In the production of the ink jet recording head 1, an ink jet is similarly performed except that a nozzle plate subjected to the following surface treatment 1 is joined to a predetermined position instead of the nozzle plate (the joint portion is not subjected to surface treatment). The recording head 10 was produced.

(Surface treatment 1)
Using a plasma irradiation apparatus DEM-451 (manufactured by Anelva; parallel plane type), 200 W 13.56 MHz was applied under an oxygen pressure of 10 Pa, and the treatment was performed for 2 minutes.

Example 7: [Production of inkjet recording head 11]
In the production of the ink jet recording head 1, an ink jet is similarly performed except that a nozzle plate subjected to the following surface treatment 2 is joined to a predetermined position instead of the nozzle plate (the joint portion is not subjected to surface treatment). The recording head 11 was produced.

(Surface treatment 2)
After immersing in 6N hydrochloric acid at 60 ° C. for 6 hours, it was washed with pure water and dried.

Example 8: [Preparation of inkjet recording head 12]
In the production of the ink jet recording head 2, ink jet recording is performed in the same manner except that the nozzle plate subjected to the surface treatment 1 is joined to a predetermined position instead of the nozzle plate (the joint portion is not subjected to surface treatment). A head 10 was produced.

Example 9: [Preparation of inkjet recording head 13]
In the production of the ink jet recording head 2, ink jet recording is performed in the same manner except that the nozzle plate subjected to the surface treatment 2 is joined to a predetermined position instead of the nozzle plate (the surface of the joint is not subjected to surface treatment). A head 13 was produced.

Example 10: [Preparation of inkjet recording head 14]
In the production of the ink jet recording head 5, ink jet recording is performed in the same manner except that the nozzle plate subjected to the surface treatment 1 is joined to a predetermined position instead of the nozzle plate (the joint portion is not subjected to surface treatment). A head 14 was produced.

Example 11: [Preparation of inkjet recording head 15]
In the production of the ink jet recording head 5, ink jet recording is performed in the same manner except that the nozzle plate subjected to the surface treatment 2 is joined to a predetermined position instead of the nozzle plate (the surface of the joint is not subjected to surface treatment). A head 15 was produced.

  The production of the head was evaluated according to the following evaluation criteria, and the results are shown in Table 1.

<Evaluation of pasting property>
Adhesive is transferred onto the front surface of the head chip, and the adhesion when the nozzle plate is bonded is observed.

  ○: There is no gap in the gap between the nozzle plate and the front surface of the chip, and the adhesive is in close contact.

  X: There is a gap in the gap between the nozzle plate and the front surface of the chip, and it does not adhere.

<Evaluation of light emission>
For each of the ink jet recording heads prepared above, an ink composed of a 70:30 mixed solution of butoxyethyl acetate and cyclohexanone was introduced, and the ink was ejected by sending a pulse signal from the drive circuit to the head, and the ejection state between the nozzles was observed. did.

  ○: Ink was emitted from all nozzles.

  X: There is a nozzle in which the adhesive flows and does not exit.

<< Durability evaluation of adhesive strength >>
Fill the head with ink consisting of cyclohexanone (SP value: 20.3) or anisole (SP value: 19.4), and plug the ink inlet so that the ink in the head does not disappear due to evaporation during storage. The nozzle surface was capped and stored in an oven at 60 ° C. for 1 month. The head was removed from the oven, and the end of the nozzle plate of each inkjet recording head was pinched with tweezers and pulled. The head in which the nozzle plate was not peeled was further filled with the same ink for 2 months (total 3 months) and stored in the same manner, and then a tensile test was performed with tweezers.

  ○: The tweezers slipped and the nozzle plate did not peel even after 3 months storage.

  (Triangle | delta): It did not peel even if it stored for 1 month, but it peeled when stored for 3 months.

  X: Peeled off after storage for 1 month.

  As is apparent from the results shown in Table 1, by using the adhesive of the present invention and the curing conditions for the adhesion of the nozzle plate of the inkjet head, the nozzle plate is excellent in bonding properties and poor emission due to the flow of the adhesive. It can be seen that even when the solvent ink is used for a long period of time, the adhesion durability is excellent. It can also be seen that the durability of the adhesive force can be further improved by irradiating the surface of the joint portion of the nozzle plate member with plasma or acid treatment before adhering the nozzle plate.

DESCRIPTION OF SYMBOLS 1 Head chip 1A, 1B Side wall surface 11 Flow path member 12 Pressure chamber 14 Connection electrode 2 Nozzle plate 21 Nozzle 3 Wiring board 31 Wiring connection part 32 Opening part 33 Wiring electrode 36a, 36b Dummy electrode 35 Joining area M Metal layer

Claims (7)

  An inkjet head having a heating step after a step of bonding a plurality of members with an adhesive containing an epoxy resin, a photocationic polymerization initiator, and a thermal cationic polymerization initiator, and a step of irradiating light to the protruding portion of the adhesive In the manufacturing method, 80 to 100% by mass of the epoxy resin is an aromatic epoxy compound, and the heating step includes a step of raising the temperature in a temperature range of 40 ° C to 150 ° C.   The method of manufacturing an ink jet head according to claim 1, wherein the heating step includes a step of increasing the temperature at a temperature increase rate of 0.1 ° C. to 2 ° C. per minute.   The method of manufacturing an ink jet head according to claim 1, wherein the heating step is performed by combining two or more isothermal processes. The said thermal cationic polymerization initiator contains the complex compound represented with the following general formula (I), The manufacturing method of the inkjet head of any one of Claims 1-3 characterized by the above-mentioned.

R represents a hydrogen atom or an alkyl group.
R ₁ , R ₂ and R _{3 each} represents a hydrogen atom, an alkyl group, an alkoxy group, an aryloxy group or a halogen atom.   The said epoxy resin contains 1-50 mass% of novolak epoxy resins, The manufacturing method of the inkjet head of any one of Claims 1-4 characterized by the above-mentioned.   The method for manufacturing an ink jet head according to claim 1, wherein at least the joining portion is plasma-irradiated on the joining portion.   6. The method of manufacturing an ink jet head according to claim 1, wherein at least a joint portion of the member is treated with an acid.

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