JP5849552B2 - Ink jet head, manufacturing method thereof, and image forming apparatus - Google Patents

Description

  The present invention relates to an inkjet head, a manufacturing method thereof, and an image forming apparatus.

  For example, an ink jet head used in an image recording apparatus such as a printer, a facsimile machine, a copying apparatus, or a plotter or an ink jet recording apparatus used as an image forming apparatus includes a nozzle that ejects ink droplets and a liquid chamber (pressure chamber) that communicates with the nozzle. A discharge chamber, a pressure chamber, a pressurized liquid chamber, and an ink flow path), and pressure generating means (driving means or energy generating means) for pressurizing ink in the liquid chamber. By driving the means, the ink in the liquid chamber is pressurized and ink droplets are ejected from the nozzles.

  As such an ink-jet head, a piezoelectric element is used to deform a diaphragm that forms the wall surface of the liquid chamber to eject ink droplets (see Patent Document 1), or a heating resistor is used. Ink droplets are ejected with pressure generated by heating the ink in the liquid chamber to generate bubbles (see Patent Document 2), and the diaphragm and the electrode forming the wall surface of the liquid chamber are arranged in parallel. There is one that ejects ink droplets by deforming the diaphragm by the electrostatic force generated between the diaphragm and the electrode (see Patent Document 3). Development is actively underway to meet the demands of computerization.

  Here, the inkjet head generally discharges ink droplets, a liquid chamber, a fluid resistance portion for supplying ink to the liquid chamber, a common ink liquid chamber for supplying the liquid chamber via the fluid resistance portion, and an ink droplet. It is necessary to form various flow paths such as liquid droplet ejection holes (nozzle holes) or nozzle grooves. For example, a flow path substrate (liquid chamber substrate) for forming a flow path such as a liquid chamber and a nozzle having a nozzle It is formed by joining members such as plates.

  Conventionally, the members constituting the ink jet head are joined by direct joining when using a silicon substrate for the liquid chamber substrate or nozzle plate, eutectic joining via a metal material, or anode when using a metal material. Although joining etc. may be performed, the adhesive joining by a wet adhesive agent, a film adhesive agent, etc. is common.

  Here, there are many parts that are bonded to the ink jet head in contact with ink, and in the case of bonding with an adhesive, the ink that comes in contact degrades the adhesive itself or penetrates into the bonding interface and causes peeling. Can cause major problems with reliability. In other words, the end of the adhesive joint is exposed to the ink in the liquid chamber of the inkjet head, and the pressure of ink ejection is applied between the members, but the ejection cycle of the inkjet head is several kHz, Since it is a member that receives pressure fluctuations, it was easy for the adhesive joint to deteriorate. For this reason, an ink resistance (also referred to as a liquid resistance) is required for a joint portion by an adhesive in an ink jet head rather than a general adhesive joint (for example, Patent Document 4). Further, in general, when two members are bonded and bonded, there is a demand for maintaining a component accuracy and realizing a highly reliable bonding.

  For this reason, it is desired that the adhesive has resistance to the ink used and has sufficient bonding strength by suppressing permeation deviation to the bonding interface as much as possible. It was extremely difficult to select a low-degrading adhesive for a specific ink.

  In particular, when a metal member is used for the nozzle plate (or liquid chamber substrate), it is necessary to use a specific adhesive, generally referred to as a metal adhesive, in order to ensure the bonding strength. Its use has been difficult because moisture interferes with maintaining its adhesion. This is because, in many adhesive resins called metal adhesives, the hydroxyl group in the molecular chain forms a hydrogen bond with the metal surface to obtain an adhesive force with the metal member. Since hydrogen bonds are easily broken by water, the adhesive strength is very strong in the dry state, but such adhesives with many hydroxyl groups can maintain the adhesion to ink for a long time. Absent.

  In Patent Document 5, a main adhesive having high ink resistance is attached to the periphery of a discharge port of a nozzle plate (discharge port forming member), and around the main adhesive from the main adhesive when the main adhesive is cured. An invention has been proposed in which an auxiliary adhesive having a low cure shrinkage is adhered. According to this, it is possible to bond the nozzle plate and the ink flow path member without shifting the position of the discharge port and the ink flow path while ensuring the ink resistance at the end of the adhesive joint exposed to the ink. Is possible.

  However, according to the present invention, when the joining portion between the nozzle plate and the ink flow path member that comes into contact with the ink is very small like a side edge type ink jet head, sufficient joining strength is secured by the auxiliary adhesive around the joining portion. However, when the area of the joint portion in the liquid chamber is large and the pressure of the ink applied to the nozzle plate is large as in the case of the laminating type ink jet head, many portions of the nozzle plate and the ink flow path member have high ink resistance. Bonding must be performed with an adhesive having a weak adhesive force. In this case, the partial adhesive force for each ink flow path (each liquid chamber) is low, and the bonding strength is not sufficient. In this case, when a high pressure is applied to the liquid chamber as a whole, the adhesively bonded portion of the partition wall is peeled off and an internal leak of the ink is generated. Therefore, it is necessary to fill and discharge the ink with a low pressure. Could not meet the required characteristics.

  The present invention has been made in view of the above-described problems in the prior art, and in a multi-layer inkjet head in which a plurality of members are stacked and bonded with an adhesive to form a liquid chamber, sufficient bonding strength and high resistance are achieved. It is an object of the present invention to provide an ink jet head having ink properties, a method for manufacturing the same, and an image forming apparatus including the ink jet head.

  The present invention provided to solve the above problems includes a nozzle plate provided with a nozzle for discharging ink, a substrate having a liquid discharge energy generating unit, and a partition wall provided between the nozzle plate and the substrate. In the inkjet head in which a plurality of liquid chambers each having the nozzles are formed, one of the bonding surface of the nozzle plate and the bonding surface of the substrate bonded to the partition is a metal material, and the other is The bonding surface of the metal material and the partition are formed of a resin material, and are bonded by a first adhesive containing an epoxy resin having a hydroxyl group in a molecular chain, and the bonding surface of the resin material and the partition are the first The adhesive is bonded with a second adhesive having a lower hygroscopicity than the adhesive, and the portion of the bonding surface between the bonding surface of the metal material and the partition that faces the inside of the liquid chamber is the tree. It is an inkjet head, characterized in that is covered by the excess of the second adhesive bonding surface and bonding the said partition wall material.

  In addition, the present invention provided to solve the above-described problems includes a nozzle plate made of a metal material and provided with a nozzle for discharging ink, a substrate having a liquid discharge energy generating unit, and a gap between the nozzle plate and the substrate. In the inkjet head, which is partitioned by a partition wall, and each of which has a plurality of liquid chambers each having the nozzle, the nozzle plate and the partition wall include a first adhesive containing an epoxy resin having a hydroxyl group as a molecular chain. The substrate made of a resin material and bonded to the partition and the partition are bonded by a second adhesive having a lower hygroscopicity than the first adhesive, and the nozzle plate and the partition An ink-bonded portion of the liquid chamber and a portion facing the liquid chamber is covered with an excess of the second adhesive that bonds the substrate and the partition. Is Ettoheddo.

  Further, the present invention provided to solve the above problems includes a nozzle plate provided with a nozzle for discharging ink, a substrate having a liquid discharge energy generating unit, a partition wall provided between the nozzle plate and the substrate, In the inkjet head in which a plurality of liquid chambers each having the nozzle are formed, any one of the bonding surface of the nozzle plate and the bonding surface of the substrate bonded to the partition wall is a metal material, and the other Is formed of a resin material, and the bonding surface of the metal material and the partition are bonded by a first adhesive containing an epoxy resin having a hydroxyl group in a molecular chain, and the bonding surface of the resin material and the partition are the first The adhesive is bonded by a second adhesive having a lower hygroscopicity than the adhesive of No. 1 and the portion of the bonding surface between the bonding surface of the metal material and the partition that faces the inside of the liquid chamber is An image forming apparatus characterized by mounting the ink jet head is covered junction surface with the excess of the second adhesive bonds the said partition wall of the resin material.

  Further, the present invention provided to solve the above problems includes a nozzle plate provided with a nozzle for discharging ink, a substrate having a liquid discharge energy generating unit, a partition wall provided between the nozzle plate and the substrate, In the method of manufacturing an ink jet head in which a plurality of liquid chambers each having the nozzle are formed, one of the bonding surface of the nozzle plate and the bonding surface of the substrate bonded to the partition is made of metal. A step of forming a material, the other as a resin material, and a first adhesive containing an epoxy resin having a hydroxyl group in a molecular chain is applied to one surface of the partition, and then the surface opposite to the one surface of the partition An adhesive application step of applying a second adhesive having a hygroscopicity lower than that of the first adhesive, a surface formed by applying the first adhesive of the partition wall, and a bonding formed by the metal material Face and A first bonding step of bonding; a second bonding step of bonding the surface of the partition wall to which the second adhesive is applied and a bonding surface formed of the resin material; and heating to form the metal material A first curing agent in a bonding portion between the bonding surface and the partition formed by the step, and a heat curing step for curing the second adhesive in the bonding portion between the bonding surface and the partition formed from the resin material; In the heat curing step, at least the second adhesive is provided with fluidity in the heating temperature rising process, and a bonded portion between the bonding surface formed of the resin material and the partition wall So that the excess of the second adhesive covers the portion facing the liquid chamber, which is the first adhesive of the bonded portion of the joining surface formed of the metal material and the partition wall. And then add A method of manufacturing an ink jet head, characterized in that curing the first adhesive and the second adhesive during the curing process.

  In addition, the present invention provided to solve the above-described problems includes a nozzle plate made of a metal material and provided with a nozzle for discharging ink, a substrate having a liquid discharge energy generating unit, and a gap between the nozzle plate and the substrate. In the method of manufacturing an ink jet head, wherein a plurality of liquid chambers each having the nozzle are formed, a first surface containing an epoxy resin having a hydroxyl group as a molecular chain on one surface of the partition wall. An adhesive application step of applying an adhesive, and then applying a second adhesive having a lower hygroscopicity than the first adhesive to a surface opposite to the one surface of the partition; A first bonding step of bonding the surface to which the adhesive of 1 is applied and the nozzle plate; and the surface of the partition to which the second adhesive is applied and the substrate having a bonding surface made of a resin material. Pasting together A second bonding step, and a heating and curing step of curing the first adhesive in the bonding portion between the nozzle plate and the partition and the second adhesive in the bonding portion between the substrate and the partition by heating. In the heat curing step, at least the second adhesive is provided with fluidity in the heating temperature increasing process, and the second adhesion at the bonding portion between the substrate and the partition wall is performed. The surplus of the agent is the first adhesive at the bonded portion of the nozzle plate and the partition wall and covers the portion facing the liquid chamber, and then the first adhesion in the heat curing process A method for producing an ink jet head, wherein the agent and the second adhesive are cured.

According to the ink jet head of the present invention, an epoxy resin having a hydroxyl group in a molecular chain is formed between a bonding surface (for example, a nozzle plate) of a metal material, which is one of a bonding surface of a nozzle plate and a bonding surface of the substrate. Since the adhesive bonding is performed by the first adhesive including, it is possible to ensure sufficient bonding strength at a bonding portion having a large area for each liquid chamber. Further, the second adhesive having a lower hygroscopicity than the first adhesive covers the adhesive joint portion between the metallic material joining surface (nozzle plate) and the partition wall and facing the liquid chamber. Therefore, even in a joint portion with a large area, the portion adhesively joined with the first adhesive from the ink in the liquid chamber is protected, sufficient ink resistance is ensured, and the necessary joint strength can be maintained for a long time. Can be reliable.
Further, according to the image forming apparatus of the present invention, since the ink jet head of the present invention is provided, it is possible to perform image formation by stable ink ejection over a long period of time.
Moreover, according to the manufacturing method of the ink jet head of the present invention, the ink jet head of the present invention is manufactured by a simple method by a predetermined adhesive coating process, a first bonding process, a second bonding process, and a heat curing process. It is possible.

1 is a perspective view illustrating a configuration of an inkjet head according to the present invention. It is sectional drawing of the liquid chamber in the inkjet head of FIG. It is sectional drawing which shows the principal part structure (1) of the inkjet head which concerns on this invention. It is process drawing which shows 1st Embodiment regarding the manufacturing method of the inkjet head which concerns on this invention. It is process drawing which shows 2nd Embodiment regarding the manufacturing method of the inkjet head which concerns on this invention. It is sectional drawing which shows the principal part structure (2) of the inkjet head which concerns on this invention. It is process drawing which shows 3rd Embodiment regarding the manufacturing method of the inkjet head which concerns on this invention. It is process drawing which shows 4th Embodiment regarding the manufacturing method of the inkjet head which concerns on this invention. 1 is an external view of a liquid cartridge according to the present invention. 1 is an external view of an ink jet recording apparatus that is an image forming apparatus according to the present invention. It is sectional drawing which shows the structure of the mechanism part of the inkjet recording device of FIG. It is a figure which shows the result of the peeling strength test (1) by the ink immersion of the joining sample of Example A. It is a figure which shows the result of the ink droplet discharge speed test (1) of the inkjet head of Example A. It is a figure which shows the result of the peeling strength test (2) by the ink immersion of the joining sample of Example A, B. It is a figure which shows the result of the ink droplet discharge speed test (2) of the inkjet head of Example A, B.

The configuration of the inkjet head according to the present invention will be described below.
FIG. 1 is a perspective view of a main part of an ink jet head according to the present invention, and FIG. 2 is a cross-sectional view of the ink jet head of FIG. 2A is a cross-sectional view in the liquid chamber short side length direction, and FIG. 2B is a cross-sectional view in the liquid chamber long side length direction.
As shown in the figure, the inkjet head 1 has a plurality of nozzles (nozzle holes 6a) for discharging droplet-like ink on a substrate (vibrating plate 3) having a piezoelectric element 2 that is a liquid discharge energy generating unit. Side shooter type, in which liquid pressure chambers (liquid chambers 5) are arranged, and droplets are ejected from nozzle holes 6 a provided in the nozzle plate 6 using a piezoelectric actuator comprising the piezoelectric element 2 and the diaphragm 3. belongs to. Specifically, the inkjet head 1 includes a piezoelectric element 2 including a common electrode 10, a piezoelectric body 12, and an individual electrode 11, a vibration plate 3, a liquid chamber 5 provided on the vibration plate 3, and a liquid chamber 5. It is composed of a fluid resistance portion 7 for supplying ink, a common liquid chamber 8, and a nozzle plate 6 provided for each liquid chamber 5 and having nozzle holes 6 a for discharging ink. The diaphragm 3 is provided with a common ink supply port 9 from which ink can be supplied to the common liquid chamber 8 from the outside.

  The liquid chamber 5 is a space surrounded by a diaphragm 3, a nozzle plate 6, and a partition wall 4 that is provided between the nozzle plate 6 and the diaphragm 3 and partitions the adjacent liquid chamber 5.

  Further, the piezoelectric element 2 formed by laminating the common electrode 10, the piezoelectric body 12, and the individual electrode 11 is formed on the surface of the diaphragm 3 opposite to the liquid chamber 5. The surface of the liquid chamber 5 that faces the diaphragm 3 is a nozzle plate 6.

  Here, the diaphragm 3 is also referred to as a diaphragm, and is a thin plate material that is flexible as the piezoelectric element 2 is driven. For example, the plate surface on the liquid chamber 5 side is coated with a resin coating such as polyimide or silicon. An Ni thin plate coated with an oxide film is used.

  The partition wall 4 is also referred to as a restrictor member or a flow path plate, and is a member sandwiched between the diaphragm 3 and the nozzle plate 6. For example, the liquid chamber 5, the fluid resistance portion 7, and the common liquid are formed on a stainless steel thin plate material. A punching hole is provided by press working to partition the chamber 8. The partition wall 4 has a thickness of 15 to 140 μm.

The nozzle plate 6 is also referred to as an orifice plate and is a plate material made of a metal material and provided with nozzle holes 6a that are through holes for discharging ink. The nozzle plate 6 is preferably made of stainless steel or a metal mainly composed of Ni or Si. The surface of the nozzle plate 6 may be coated with a metal oxide such as SiO ₂ .

In the ink jet head 1 configured as described above, each liquid chamber 5 is filled with a liquid, for example, a recording liquid (ink), and the recording liquid is supplied by an oscillation circuit based on image data from a control unit (not shown). A pulse voltage of 20V is applied to the individual electrode 11 corresponding to the nozzle hole 6a to be discharged. By applying this voltage pulse, the piezoelectric body 12 bends so that the piezoelectric plate 12 itself contracts in the direction parallel to the vibrating plate 3 due to the electrostrictive effect, so that the vibrating plate 3 becomes convex toward the liquid chamber 5 side. It will be. As a result, the pressure in the liquid chamber 5 rapidly increases, and the liquid recording liquid is ejected from the nozzle hole 6 a communicating with the liquid chamber 5. Next, since the contracted piezoelectric body 12 returns to its original position after the pulse voltage is applied, the deflected diaphragm 3 returns to its original position, so that the liquid chamber 5 has a negative pressure compared to the common liquid chamber 8. Thus, the recording liquid is supplied from the common liquid chamber 8 through the fluid resistance portion 7 to the liquid chamber 5.
By repeating the above operation control, the inkjet head 1 can continuously discharge droplets, and an image can be formed on a recording medium (paper) disposed facing the inkjet head 1.

  Here, in the inkjet head 1 in which the liquid chamber 5 is formed by laminating a plurality of such members, the liquid chamber 5 has a high adhesiveness and a high liquid contact property (ink resistance) with respect to ink at a joint portion having a large area. Adhesive bonding with both is required. However, it has been difficult to achieve both high adhesion and high ink resistance by adhesive bonding.

  In particular, the problem was remarkable at the joint portion between the nozzle plate 6 made of a metal material and the partition wall 4. Here, with respect to adhesive bonding with a metal member, sufficient bonding strength can be obtained even with, for example, the second adhesive by coating the surface of the metal member with resin or applying a ground treatment with a silane coupling agent. However, since such a resin or silane coupling agent has water repellency, the ink filling property of the liquid chamber 5 is deteriorated, or the resin in the nozzle hole 6a of the nozzle plate 6 is deteriorated. Or a silane coupling agent adheres, and the meniscus holding power is weakened, resulting in problems such as poor ink ejection stability.

  Therefore, in order to achieve both high adhesion and high ink resistance in adhesive bonding, it is important to select an adhesive, particularly a main resin. However, for example, in the molecular chain shape of the main resin of the adhesive, the cured resin having a long-chain molecular shape with few branches has high peel strength because the cured resin is highly elastic. However, if the molecular chain is a long chain, the steric hindrance is large and a large gap is formed between the molecules, so that the ink component easily enters the gap. Therefore, the cured resin composed of the long chain molecule has a hygroscopic property. It becomes high, easily swells, and the strength tends to decrease. That is, the resin has low ink resistance.

  In addition, in the functional group in the molecular chain of the main resin of the adhesive, the resin having a hydroxyl group in the molecular chain has a property that the hydroxyl group forms a hydrogen bond. Creates hydrogen bonds with hydroxyl groups and has high adhesion. However, since the resin having the hydroxyl group in the molecular chain is also a hydrophilic group, the cured resin has high hygroscopicity, easily swells, and the hydrogen bond is broken, so that the strength is easily lowered. That is, the resin has low ink resistance.

  In this way, the main resin of the adhesive has a strong chemical trade-off between adhesiveness and ink resistance, so it is difficult to achieve both adhesiveness and ink resistance with a single main resin. there were. For this reason, the main resin of the adhesive may be selected according to the application, and a material that is balanced with respect to the shape and size of the molecular chain and the number of functional groups, or a prescription in which a plurality of resins are mixed in a balanced manner. It is common.

On the other hand, in recent years, there has been an increasing demand for both adhesiveness and ink resistance for ink jet head adhesives. That is, the ink jet head is required to be miniaturized and enlarged, and accordingly, the partition wall 4 becomes thinner, the liquid chamber 5 becomes smaller and thinner, and the bonding area exposed to the liquid chamber 5 becomes relatively larger. In addition, since the bonding area of the entire inkjet head is increased, the inkjet head is required to have high adhesiveness. Further, in order to improve the image quality, there is a demand for the ink to have higher penetrability, but this is a severe demand for the ink resistance of the adhesive. However, with regard to the preparation of the adhesive, in the general method as described above, the above-mentioned trade-off problem is in response to the recent demand for compatibility between the adhesive for ink jet heads and the increased ink resistance. Could not be satisfied in the face of.
The present invention has been completed by the inventor's earnest study to solve this problem. Hereinafter, the fundamental part of the present invention will be described.

  In the embodiment of the inkjet head according to the present invention, as described above, the joint surface of the nozzle plate 6 formed of a metal material and the partition wall 4 are bonded by a first adhesive containing an epoxy resin having a hydroxyl group as a molecular chain. As described above, the joint surface of the diaphragm 3 coated with a resin such as polyimide and the partition wall 4 are bonded to each other by a second adhesive having a lower hygroscopic property than the first adhesive. The portion of the adhesive joint between the partition wall 4 and the liquid chamber 5 is covered with an excess of the second adhesive that bonds the diaphragm 3 and the partition wall 4 to each other. Is.

  FIG. 3 is a schematic cross-sectional view showing the main configuration (1) of the inkjet head according to the present invention. Here, the joining portion in the liquid chamber unit that is partitioned by the nozzle plate 6, the vibration plate 3, and the partition wall 4 provided between the nozzle plate 6 and the vibration plate 3 to form a plurality of liquid chambers 5. A schematic diagram is shown.

  As shown in FIG. 3, the adhesive bonding portion between the diaphragm 3 and the partition 4 is made of a cured resin 22 obtained by curing the second adhesive, and not only the gap between the diaphragm 3 and the partition 4 but also the liquid chamber 5. It protrudes to the side (left and right direction in the figure).

  Further, the adhesive bonding portion between the nozzle plate 6 and the partition wall 4 is made of a cured resin 21 in which the first adhesive is cured. Direction).

  Further, the portion of the cured resin 21 facing the inside of the liquid chamber 5 is in a state where the surplus portion of the second adhesive that bonds the diaphragm 3 and the partition 4 is covered with the cured resin 23 that has been cured. . The surplus of the second adhesive is a case where the diaphragm 3 and the partition 4 are bonded together as a result of the second adhesive applied for the adhesive bonding of the diaphragm 3 and the partition 4 at the beginning. In addition, the portion that protrudes from between the diaphragm 3 and the partition wall 4 does not contribute to the adhesive bonding between the two.

  Here, the first adhesive is any one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin having an epoxy equivalent of 160 or more as a main resin suitable for adhesive bonding of metal members. It is preferable to include. These resins have a hydroxyl group in the molecular chain, and can form a hydrogen bond with a metal to obtain high adhesion.

  In addition, what hardened | cured the 1st adhesive agent (cured resin 21) is good to have high elasticity as much as possible, and has higher elasticity than the cured resin 22 which the 2nd adhesive agent hardened at least. In order to obtain high elasticity, a high molecular weight epoxy resin having a relatively long chain and few branches is preferred, but it has a glass transition point lower than the curing start temperature of the curing agent, and at a temperature lower than the temperature at which the curing reaction starts. Since it is preferable to have fluidity, problems occur even if the molecular weight is too high. Therefore, a molecular weight of 900-60000 is good.

  For example, bisphenol A type epoxy resin (trade name jER1010, manufactured by Mitsubishi Chemical Corporation) is a long-chain, high-molecular-weight epoxy resin having many hydroxyl groups, and is cured to exhibit a high elastic modulus. For this reason, it has a particularly high adhesion to metal, but on the other hand, the hydrogen bond formed by the hydroxyl group is fragile to water, so the ink resistance is not so high.

  The second adhesive is a main resin having excellent moisture absorption resistance, such as biphenyl type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene (DCPD) type epoxy resin, naphthalene type epoxy resin. Any of xanthene type epoxy resins is preferable. These are low hygroscopic resins and are also used mainly as coating materials for semiconductors and the like, and the cured resins 22 and 23 block the penetration of moisture from the water-based ink used in the present invention. In addition, when these resins are cured, they form an epoxy resin having a relatively high cross-linking density and exhibit excellent chemical resistance.

  For example, a DCPD type epoxy resin (trade name EPICLON HP-7200HH, manufactured by DIC Corporation) does not have a hydroxyl group in the molecular chain and has a small steric hindrance, and thus exhibits a low moisture absorption rate after curing. For this reason, although it has high ink resistance, on the other hand, since there are many branches and molecular weight is small, cured resin becomes rigid and does not have the adhesive force like a 1st adhesive agent.

  The first adhesive and the second adhesive preferably contain an amine curing agent. Specific examples of the curing agent include primary and secondary amines such as aliphatic polyamines, alicyclic polyamines, aromatic polyamines, and polyaminoamides.

By using the amine-based curing agent, the first adhesive and the second adhesive form a resin having high elasticity because the molecular chain of the resin after the curing reaction is long, and the peel strength is increased. At the same time, since the coupling reaction occurs without making a branch in the molecular chain, it becomes difficult to form a gap that causes steric hindrance between the molecular chains, and the moisture resistance of the binding resin is lowered, resulting in an improvement in ink resistance. .
As described above, the inventor presumes a preferable reason for the present invention. However, the present invention does not depend on the above inference.

  In the present invention, the curing agent contained in the first adhesive and the curing agent contained in the second adhesive are preferably cured at the same temperature, and more preferably simply the same. Because the main epoxy resin is different between the first adhesive and the second adhesive and there is a difference in the coefficient of thermal expansion, etc., depending on the thermal history, at the interface where the first adhesive and the second adhesive contact There is a concern of causing interfacial peeling. In the present invention, each of the curing agents is simply the same so that the reaction starts at the same temperature, so that both adhesives start the reaction at the same time, and the contacting interface is firmly bonded. It is possible to prevent peeling.

Further, the solvent contained in the first adhesive and the solvent contained in the second adhesive are preferably the same.
If the first adhesive and the second adhesive form a clear interface due to the difference in drying speed, or if the compatibility is poor and a clear interface is formed by the action of liquid phase separation, the ink remains as it is. This is because the moisture of the ink tends to enter along the interface, and the ink resistance may deteriorate. By making the solvent contained in each adhesive the same, it is possible to harden the interface between the first adhesive and the second adhesive in an ambiguous state.

  A silane coupling agent can also be mixed in the first adhesive and the second adhesive. As a result, it is possible to supplementarily improve the adhesive strength and ink resistance.

The example of the coupling agent used for these is shown below.
·Silane coupling agent
2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane,
N-2 (-aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2 (-aminoethyl) -3-aminopropylmethyldiethoxysilane, N-2 (-aminoethyl) -3-aminopropyltrimethoxy Silane, N-2 (-aminoethyl) -3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, (1,3-dimethyl-butylidene) -propylamine, N- Phenyl-3-aminopropyltrimethoxysilane, N, N-bis (3- (trimethoxysilyl) propyl) ethylenediamine, N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propane Amines, 3-phenylaminopropyltrimethoxysilane,
Aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, N- (2- (vinylbenzamino) ethyl) -3-aminopropyltrimethoxysilane hydrochloride, 1,2-ethanediamine, N- {3- (Trimethoxysilyl) propyl}-, N-{(ethenylphenyl) methyl} derivatives and hydrochloride
3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane,
3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane,
Bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanatopropyltriethoxysilane The organic group of the silane coupling agent preferably has a functional group that reacts with the epoxy resin, and the above coupling agent is an example . These can be purchased from Shin-Etsu Chemical, Toray Dow Corning, Chisso and others.

・ Titanate and aluminate coupling agents Tetra-i-propoxytitanium, tetra-n-butoxytitanium, tetrakis (2-ethylhexyloxy) titanium, titanium-i-propoxyoctylene glycolate, di-i-propoxy bis (Acetylacetonato) titanium, poly (di-i-propoxy-oxytitanium), poly (di-n-butoxy-oxytitanium), di-n-butoxy-bis (triethanolaminato) titanium, diisopropoxy- Bis (triethanolamine) titanium, isopropyltri (N-amidoethyl / aminoethyl) titanate, acetoalkoxyaluminum diisopropylate titanate and aluminate coupling agents can form a polymer organic coating on inorganic surfaces. Improve the adhesive strength by improving the wettability of the adhesive. The above is one example of a titanate coupling agent and is not limited. These can be purchased from Mitsubishi Gas Chemical, Nippon Soda and Ajinomoto Fine Techno.

  Any of the above coupling agents can be used. However, a coupling agent having an epoxy group or an amine group is preferred, and the first adhesive, which is an epoxy adhesive, is used as the coupling agent. In order to exert the effect by adding to the adhesive of No. 2, an epoxy group coupling agent is preferable from the aspect of the effective period of the adhesive from the viewpoint that the reaction does not proceed at room temperature.

  Further, the first adhesive and the second adhesive may include a filler, other binder resin, a viscosity modifier, and the like in addition to the above-described epoxy resin, curing agent, solvent, and coupling agent. The filler may be inorganic particles such as silica or alumina, or resin fine particles of melamine resin or acrylic resin. It is also possible to add a higher fatty acid amide or the like as a viscosity modifier to adjust the viscosity to a suitable one by applying an adhesive. Moreover, since the coating spot by a bubble does not generate | occur | produce in a coating film, you may add a foam suppressor and an antifoamer.

  As described above, according to the ink jet head of the present invention, the diaphragm 3 and the partition wall 4 are bonded and bonded with sufficient bonding strength by the cured resin 22 which is the bonded bonding portion by the second adhesive, and is cured. Since the resin 22 is excellent in moisture absorption resistance, the bonding strength does not deteriorate for a long time even if the resin 22 is in contact with the ink in the portion exposed to the liquid chamber 5.

  Moreover, since the cured resin 21 which is an adhesive bonding portion by the first adhesive is made of the first adhesive containing an epoxy resin having a hydroxyl group in the molecular chain, the nozzle plate 6 and the partition wall 4 are separated by hydrogen bonding of the hydroxyl group. Although the adhesive bonding is performed with sufficient bonding strength, since the moisture absorption resistance is inferior as described above, the bonding strength deteriorates due to the moisture of the ink that has been exposed to the liquid chamber 5 as it is.

  Therefore, in the present invention, as shown in FIG. 3, the portion of the curable resin 21 facing the inside of the liquid chamber 5 is cured by surplus of the second adhesive that bonds the diaphragm 3 and the partition 4. The state is covered with the resin 23. Thereby, even if the liquid chamber 5 is filled with ink, the cured resin 23 having excellent moisture absorption resistance prevents the ink from coming into contact with the cured resin 21, and also prevents the ink from penetrating. The bonding strength between 6 and the partition 4 is not deteriorated.

  In addition, by ensuring sufficient bonding strength and ink resistance at each partition wall 4 in this way, even when many liquid chambers 5 are arranged and a large area of adhesion is required, the entire inkjet head 1 has a large area. Therefore, it is possible to prevent a problem that only the partition wall 4 of the liquid chamber 5 peels off inside the inkjet head 1 and causes internal leakage of the ink for a long period of time.

  The effect of the present invention can be obtained if the bonding surface with the partition wall 4 by the adhesive is formed of one resin material and the other is formed of a metal material. At this time, one of the nozzle plate 6 and the diaphragm 3 may be formed of the metal material itself, and the other may be formed of the resin material itself, or a metal thin film or a resin coating may be applied only to each joint surface. Good.

  In the above-described embodiment, the joint surface of the nozzle plate 6 with the partition wall 4 is formed of a metal material, and the joint surface of the diaphragm 3 with the partition wall 4 is formed of a resin material (resin coating such as polyimide). However, the present invention is not limited to this, and the bonding surface of the nozzle plate 6 with the partition wall 4 may be formed of a resin material, and the bonding surface of the vibration plate 3 with the partition wall 4 may be formed of a metal material. In this case, the above-mentioned first adhesive is used for the joint portion between the diaphragm 3 and the partition wall 4, and the above-described second adhesive is used for the joint portion between the nozzle plate 6 and the partition wall 4. The same effect can be produced by setting the first adhesive cured with the surplus of the coated state.

  That is, bonding between the partition wall 4 and the bonding surface made of a metal material is performed using a first adhesive containing an epoxy resin having a hydroxyl group in the molecular chain that has good bondability to metal but poor ink resistance. The bonding between the partition wall 4 and the bonding surface made of the resin material is performed with a low-hygroscopic second adhesive having excellent ink resistance, and the first adhesive is covered with the second adhesive. The ink resistance of the joint between the partition wall 4 and the joint surface made of a metal material is also improved. Note that the partition 4 is entirely covered with the second adhesive as shown in FIG. 3 and there is no interface in contact with the ink, so that the adhesive does not peel off regardless of the material.

Next, a method for manufacturing the ink jet head (the ink jet head 1 shown in FIG. 3) according to the present invention will be described.
FIG. 4 is a process diagram showing a first embodiment relating to a method of manufacturing an inkjet head according to the present invention. Here, a cross-sectional view of the liquid chamber unit in the direction of the short side of the liquid chamber is shown.
Hereafter, the manufacturing process of the inkjet head 1 of this invention is demonstrated according to FIG.

(S11) First, a partition wall 4 is prepared in which a punched hole is formed in a stainless steel sheet material by press working for partitioning the liquid chamber 5, the fluid resistance portion 7, and the common liquid chamber 8 (FIG. 4A).
(S12) After applying the first adhesive 21a to one surface (upper surface in the figure) of the partition wall 4, the solvent contained in the first adhesive 21a is evaporated (FIG. 4B). At this time, the first adhesive 21 a is not applied only to the joint surface of the partition wall 4 with the nozzle plate 6, but may be applied so as to slightly cover the surface that forms the wall surface of the liquid chamber 5.
(S13) Next, the surface of the partition 4 opposite to the surface to which the first adhesive 21a is applied (in FIG. 4, the partition 4 is inverted after the application of the first adhesive 21a, so the upper surface). After applying the second adhesive 22a, the solvent contained in the second adhesive 22a is evaporated (FIG. 4C). At this time, the second adhesive 22a is not applied only to the joint surface of the partition wall 4 with the diaphragm 3, but the second adhesive 22a and the first In the boundary part of the adhesive agent 21a, it is good to apply | coat so that the 2nd adhesive agent 22a may be in the state which has covered a little on the 1st adhesive agent 21a. Further, the application amount of the second adhesive 22a may be larger than that of the first adhesive 21a so that a surplus is generated when the diaphragm 3 and the partition wall 4 are bonded.
The steps S12 and S13 are the adhesive application process.

(S14) The surface of the partition wall 4 on which the first adhesive 21a is applied is bonded to the nozzle plate 6 made of a metal material (FIG. 4 (d), first bonding step). As a result, the first adhesive 21a is crushed between the nozzle plate 6 and the partition wall 4, and slightly protrudes toward the liquid chamber 5 like the cured resin 21 in the adhesive joint portion of FIG. At this time, bonding is performed so that the nozzle hole 6 a is disposed at a predetermined position between the partition walls 4. When the plate surface of the nozzle plate 6 is covered with a metal oxide such as SiO ₂ , the nozzle plate 6 surface may be bonded after plasma treatment.
(S15) Next, the surface of the partition wall 4 on which the second adhesive 22a is applied and the vibration plate 3 on which the resin coating is applied to the bonding surface are bonded together (FIG. 4E, second bonding step). As a result, the second adhesive 22a is crushed between the diaphragm 3 and the partition wall 4, and slightly protrudes toward the liquid chamber 5.

(S16) Heating is performed in a state where the partition wall 4 is sandwiched between the diaphragm 3 and the nozzle plate 6, and the first adhesive 21a at the bonded portion of the nozzle plate 6 and the partition wall 4, the diaphragm 3 and the partition wall 4 The second adhesive 22a at the bonded portion is cured (heat curing step). Here, the heating pattern is assumed to be gradually heated, then held at a predetermined curing temperature, and then gradually cooled to room temperature. As a result, the following processing is performed.

(Temperature raising process) By gradually raising the temperature in the first half of heating, the first adhesive 21a and the second adhesive 22a have fluidity, and surplus of the second adhesive 22a applied later. Due to the surface tension, the portion smoothly covers the portion of the first adhesive 21a at the bonded portion of the nozzle plate 6 and the partition wall 4 that faces the liquid chamber 5 (FIG. 4 (f)). . At this time, in order for the first adhesive 21a and the second adhesive 22a to have fluidity, the main resin (monomer resin) of the first adhesive 21a and the main resin of the second adhesive 22a (Monomer resin) It is necessary to select a material whose fluidity is lower than the curing temperature. Further, since the movement of the excess amount of the second adhesive 22a depends on the surface tension, the upper and lower relations of the vibration plate 3 and the nozzle plate 6 may be upper, but the movement of the excess amount of the second adhesive 22a is gravity. Since the first adhesive 21a can be coated more quickly when is applied, the diaphragm 3 is preferably positioned above the nozzle plate 6 as shown in FIG. At the same time, the solvents of the respective adhesives volatilize by heating. However, it is preferable that the solvents of the first adhesive 21a and the second adhesive 22a be the same because layer separation between the two hardly occurs.

(Heating and curing process) When the temperature is further raised and the reaction start point of the curing agent is exceeded, the curing reaction of the first adhesive 21a and the second adhesive 22a starts, and the first adhesive 21a is changed to the first as described above. The first adhesive 21a and the second adhesive 22a are cured in a state where the excess of the second adhesive 22a is covered (the state shown in FIG. 4F). At this time, if the curing agent of the first adhesive 21a and the curing agent of the second adhesive 22a are the same, the curing reaction starts almost simultaneously with the first adhesive 21a and the second adhesive 22a. The epoxy resins of the first adhesive 21a and the second adhesive 22a are also cured as one cured resin by the curing agent. As a result, it is possible to prevent problems such as interfacial separation between the cured first adhesive 21a (cured resin 21) and the cured second adhesive (cured resin 23), Infiltration of the ink component along the interface can also be prevented.

(Slow cooling process) Since the thermal expansion coefficient is different between the cured first adhesive 21a (cured resin 21) and the cured second adhesive 22a (cured resin 23), rapid cooling between the two Since interfacial peeling may occur, it is preferable to cool slowly in order to avoid this.

  As described above, according to the method of manufacturing an inkjet head of the present invention, the inkjet of the present invention can be performed by a simple method using a predetermined adhesive coating process, a first bonding process, a second bonding process, and a heat curing process. The head 1 can be manufactured.

FIG. 5 is a process diagram showing a second embodiment relating to a method of manufacturing an inkjet head according to the present invention. Here, a cross-sectional view of the liquid chamber unit in the direction of the short side of the liquid chamber is shown.
The present embodiment is different from the first embodiment in that the first bonding process and the second bonding process are performed at the same time, and the first half process (FIGS. 5A to 5C) is performed in step S11. To S13 (FIGS. 4A to 4C). Therefore, here, the steps shown in FIGS. 5D and 5E will be described.

(S24) The nozzle plate 6 is arranged on the surface side of the partition wall 4 on which the first adhesive 21a is applied, and the diaphragm 3 on the surface side of the partition wall 4 on which the second adhesive 22a is applied. And the nozzle plate 6 made of a metal material and the diaphragm 3 having a resin coating layer formed on the bonding surface are bonded to the partition wall 4 (FIG. 5 (d) bonding step). As a result, the first adhesive 21a is crushed between the nozzle plate 6 and the partition wall 4, and slightly protrudes toward the liquid chamber 5 like the cured resin 21 in the adhesive joint portion of FIG. Further, the second adhesive 22a is crushed between the diaphragm 3 and the partition wall 4, and slightly protrudes to the liquid chamber 5 side.

(S25) Heating is performed in a state where the partition wall 4 is sandwiched between the diaphragm 3 and the nozzle plate 6, and the first adhesive 21a at the bonded portion of the nozzle plate 6 and the partition wall 4, the diaphragm 3 and the partition wall 4 The second adhesive 22a at the bonded portion is cured (heat curing step). Here, as in the first embodiment, the heating pattern is gradually raised in temperature, then held at a predetermined curing temperature, and then gradually cooled to room temperature. As a result, the bonding process proceeds as follows.

(Temperature raising process) By gradually raising the temperature in the first half of heating, the first adhesive 21a and the second adhesive 22a have fluidity, and surplus of the second adhesive 22a applied later. Due to the surface tension, the portion smoothly covers the portion of the first adhesive 21a in the bonded portion between the nozzle plate 6 and the partition wall 4 that faces the inside of the liquid chamber 5 (FIG. 5 (e)). .
(Heat-curing process) The temperature of the first adhesive is further increased and the first adhesive 21a is covered with the excess of the second adhesive 22a as described above (the state shown in FIG. 5E). 21a and the second adhesive 22a are cured.
(Slow cooling process) Slow cooling is performed to prevent interfacial delamination between the cured first adhesive 21a (cured resin 21) and the cured second adhesive 22a (cured resin 23). .

  As described above, according to the method for manufacturing an ink jet head of the present invention, the ink jet head 1 of the present invention can be manufactured by a simple method by a predetermined adhesive coating process, a bonding process, and a heat curing process. It is.

  In the embodiment of the manufacturing method described above, the nozzle plate 6 having a bonding surface with the partition wall 4 formed of a resin material is used, and the vibration plate 3 having a bonding surface with the partition wall 4 formed of a metal material. May be. In this case, the first adhesive is used in the joining process of the diaphragm 3 and the partition wall 4, the second adhesive is used in the joining process of the partition plate 4 of the nozzle plate 6, and the second adhesive is used. The same effect can be produced by performing the step of coating the first adhesive cured with the excess of the above.

  By the way, in the adhesive bonding around the liquid chamber 5 of the ink jet head 1, in order to ensure the bonding strength, it is necessary to protrude the adhesive to some extent, but a problem arises even if the protruding amount is too large. That is, in the inkjet head 1, when the partition wall 4 and the nozzle plate 6 are bonded, if the first adhesive 21a protrudes into the liquid chamber 5 and enters the nozzle hole 6a, normal ejection is hindered. Further, when the partition wall 4 and the diaphragm 3 are bonded, if the protrusion of the second adhesive 22a into the liquid chamber 5 is too large, the deformation of the diaphragm 3 is hindered.

In particular, the inkjet 1 shown in FIG. 3 has a configuration in which the first adhesive 21 a that protrudes in the liquid chamber 5 is covered with the second adhesive 22 a from the outside, so that the adhesive protrudes into the liquid chamber 5. The amount was easy to grow. In addition, in order to prevent the occurrence of problems due to the adhesive sticking out into the liquid chamber 5 and to ensure sufficient liquid contact properties with respect to the ink at the adhesive joint portion, the application amount of the first adhesive 21a is limited to a small amount. Thus, it is conceivable to reduce the amount of protrusion of the first adhesive 21a and to cover the first adhesive 21a thickly with the second adhesive 22a. However, the adhesive strength between the partition wall 4 and the nozzle plate 6 is not sufficient. It was enough.
The inventor tried to solve this problem by devising the joint surface of the partition wall 4. The embodiment will be described below.

  FIG. 6 is a schematic cross-sectional view showing the main configuration (2) of the inkjet head according to the present invention. Here, the joint portion in the liquid chamber unit that is partitioned by the nozzle plate 6, the vibration plate 3, and the partition wall 4 ′ provided between the nozzle plate 6 and the vibration plate 3, thereby forming a plurality of liquid chambers 5. The schematic diagram is shown.

  Compared with the configuration of the inkjet head 1 of FIG. 3, the inkjet head of this configuration differs in the protruding state of the cured resins 21, 22, and 23 at the partition wall 4 ′ and the adhesive bonded portion, and is otherwise the same as that of FIG. is there. Therefore, here, a different part from the configuration of FIG. 3 will be described.

  First, the partition 4 'is a member sandwiched between the diaphragm 3 and the nozzle plate 6 and is provided with a punched hole by press working for partitioning the liquid chamber 5 and the like in a stainless steel thin plate material, for example. It is. Here, the surface of the partition wall 4 ′ that is bonded to the nozzle plate 6 (hereinafter referred to as the surface to be bonded) is roughened and is provided with fine irregularities. Specifically, the surface of the partition wall 4 ′ that adheres to the nozzle plate 6 has a relief groove 4a through which the first adhesive 21a can flow, and fine irregularities are formed by the plurality of relief grooves 4a. Has been.

The escape groove 4a is a plurality of fine grooves having a width and a depth of about 0.5 to 10 μm and aligned in the length direction to some extent, and in the surface to be bonded to the nozzle plate 6 of the partition wall 4 ′, To the liquid chamber 5 is limited. That is, it is preferable that the fine unevenness formed by the escape groove 4a does not communicate with the liquid chamber 5, or communicates almost regularly and evenly. If the concave portion of the surface of the partition wall 4 ′ that adheres to the nozzle plate 6 communicates with the liquid chamber 5, the protrusion of the adhesive (first adhesive 21 a) at that portion becomes relatively large. This is because if the protruding amount of the protruding adhesive varies greatly among the liquid chambers 5, it becomes difficult to eject ink at a constant speed between nozzles, which may cause variations in landing positions. Therefore, it is preferable to form the relief groove 4a so that the width of the adhesive protruding into the liquid chamber 5 is substantially uniform. In FIG. 6, the escape groove 4 a is arranged so that its length direction is perpendicular to the paper surface (the length direction of the liquid chamber 5 in FIG. 1). Further, the escape grooves 4a are not completely independent, but a structure in which the escape grooves 4a are partially connected is preferable. Thereby, it is possible to remove the air that has entered the escape groove 4a together with the first adhesive 21a.
Further, the width and depth of the escape groove 4a may be appropriately adjusted according to the concentration, wettability, and melt viscosity of the first adhesive 21a to be applied.

In the present embodiment, the first adhesive 21a is an adhesive using epoxy that is liquid at room temperature from the viewpoint of adhesive strength, or an adhesive having fluidity at room temperature immediately after application, in which a resin is dissolved in a solvent. It is preferable that it is an agent. If there is a pool of air in the escape groove 4a, the air trapped by heating to cure the adhesive expands, causing a decrease in adhesive strength. Therefore, the escape groove 4a is made of a fluid adhesive. It is buried and bonded after the escape groove 4a is in a state where no air is trapped.
In addition, when using a solid epoxy resin at normal temperature as the first adhesive 21a, it is possible to have tackiness by blowing off the solvent, so that the handling of the member at the time of adhesive bonding becomes easy. Moreover, since the elasticity modulus of an epoxy resin is high, adhesive force becomes high. However, since the melt viscosity tends to be low, in order to cope with the escape groove 4a, it is preferable to dissolve in a solvent or the like at the application stage so as to have fluidity. Moreover, in the gel-like 1st adhesive agent 21a, there exists a need to forcibly distribute this adhesive agent to the escape groove 4a by pressurization etc. As shown in FIG.

  As described above, according to the inkjet head 1 of the present embodiment, as in the case of FIG. 3, the nozzle plate 6 and the partition 4 ′ are made of the first adhesive 21a containing an epoxy resin having a hydroxyl group in the molecular chain. Since the adhesive bonding is performed, a sufficient bonding strength can be ensured in a bonding portion having a large area for each liquid chamber 5. In addition, the second adhesive 22a having a lower hygroscopicity than the first adhesive 21a covers the adhesive bonding portion between the nozzle plate 6 and the partition wall 4 ′ and facing the liquid chamber 5 inside. Even in a joint portion having a large area, the portion (cured resin 21) that is adhesively bonded with the first adhesive 21a is protected from the ink in the liquid chamber 5, and sufficient ink resistance is ensured, and the required bonding strength. Can be held for a long period of time, and it becomes highly reliable.

  Further, as an excellent effect peculiar to the present embodiment, the relief groove 4a is provided on the surface of the partition wall 4 'that adheres to the nozzle plate 6 so that the same amount of the first adhesive 21a is applied and the nozzle plate 6 is attached. When combined, the amount of protrusion of the first adhesive 21a to the liquid chamber 5 side is smaller than in the case of the partition wall 4 not provided with the escape groove 4a (FIG. 3) (FIG. 6). Accordingly, no adhesive is applied to the nozzle hole 6a, and it is possible to reliably obtain normal ejection performance as the inkjet head 1. In addition, the cured resin 21 of the first adhesive 21a can be covered more thickly with the excess cured resin 23 of the second adhesive 22a at the bonded joint portion between the partition wall 4 ′ and the nozzle plate 6 ( 6), ink resistance (wet contact with ink) can also be improved. Further, since the surface area of the surface of the partition wall 4 ′ that adheres to the nozzle plate 6 is increased by forming the relief groove 4a, the bonding area with the first adhesive 21a is increased, and a stronger adhesive strength is obtained. It can be secured. Furthermore, since the thickness of the cured resin 21 between the partition wall 4 ′ and the nozzle plate 6 can be increased by the depth of the escape groove 4 a, high elasticity can be imparted to the joint portion between the partition wall 4 ′ and the nozzle plate 6. The durability of the inkjet head 1 can be improved.

  As shown in FIG. 6, a clearance groove 4b, which is a fine groove similar to the clearance groove 4a, is also provided on the surface (the upper surface in the drawing) of the partition wall 4 'that adheres to the diaphragm 3, Fine irregularities may be formed on the surface. As a result, the surface area of the partition 4 'that adheres to the diaphragm 3 is increased, so that the bonding area with the second adhesive 22a is increased, and a stronger adhesive strength can be ensured. Further, since the thickness of the cured resin 22 between the partition wall 4 ′ and the diaphragm 3 can be increased by the depth of the escape groove 4b, high elasticity can be imparted to the joint portion between the partition wall 4 ′ and the diaphragm 3. The durability of the inkjet head 1 can be improved.

  As a method for forming the relief grooves 4a and 4b, any method such as polishing, etching, or a method using a burr generated by a press method may be used, and it is not particularly limited.

Next, a method for manufacturing the ink jet head (the ink jet head 1 shown in FIG. 6) according to the present invention will be described.
FIG. 7 is a process diagram showing a third embodiment relating to a method of manufacturing an ink jet head according to the present invention. Here, a cross-sectional view of the liquid chamber unit in the direction of the short side of the liquid chamber is shown.
This embodiment is different from the first embodiment in that a partition wall 4 ′ having escape grooves 4a and 4b is used instead of the partition wall 4, and the other conditions are the same. Therefore, here, the description will focus on the differences from the first embodiment.

(S31) First, a punched hole for partitioning the liquid chamber 5, the fluid resistance portion 7, and the common liquid chamber 8 on a stainless steel thin plate material, and a partition wall 4 ′ provided with relief grooves 4a and 4b by polishing or the like Is prepared (FIG. 7A).
(S32) After applying the first adhesive 21a to one surface (upper surface in the figure) of the partition wall 4 ', the solvent contained in the first adhesive 21a is evaporated (FIG. 7B).
(S33) Next, the surface of the partition 4 'opposite to the surface to which the first adhesive 21a is applied (in FIG. 7, the partition 4' is inverted after the first adhesive 21a is applied, so the upper side After the second adhesive 22a is applied to the surface), the solvent contained in the second adhesive 22a is evaporated (FIG. 7C).
The steps S32 and S33 are the adhesive application process.

(S34) The surface of the partition wall 4 ′ to which the first adhesive 21a is applied is bonded to the nozzle plate 6 (FIG. 7D, first bonding step). As a result, the first adhesive 21a is crushed between the nozzle plate 6 and the partition wall 4 ′, and slightly protrudes toward the liquid chamber 5 like the cured resin 21 in the adhesive joint portion of FIG. Due to the escape groove 4a formed in the ', the amount of protrusion can be reduced even if the same amount of the first adhesive 21a is applied as compared with the case where there is no escape groove (FIG. 4).
(S35) Next, the surface of the partition wall 4 ′ to which the second adhesive 22a is applied is bonded to the diaphragm 3 (FIG. 7E, second bonding step). As a result, the second adhesive 22a is crushed between the diaphragm 3 and the partition wall 4 ′ and slightly protrudes toward the liquid chamber 5.

(S36) Heating is performed in a state where the partition wall 4 'is sandwiched between the diaphragm 3 and the nozzle plate 6, and the first adhesive 21a, the diaphragm 3 and the partition wall 4 at the bonded portion of the nozzle plate 6 and the partition wall 4' are combined. The second adhesive 22a in the bonded portion with 'is cured (heat curing step).
The heating pattern in this step, that is, the conditions of the temperature raising process, the heat curing process, and the slow cooling process are the same as those in the first embodiment (FIG. 4), and the phenomenon that occurs in each process is also the case of the first embodiment. Is the same. In addition, since the escape groove 4a is formed on the side of the partition 4 'where the nozzle plate 6 is joined, the amount of protrusion of the first adhesive 21a is suppressed compared to the case where there is no escape groove (FIG. 4). Therefore, the first adhesive 21a of the bonded portion between the nozzle plate 6 and the partition wall 4 ′ and the portion facing the inside of the liquid chamber 5 is smaller than the case of FIG. The surplus portion of the moving second adhesive 22a can be relatively thickly covered.

  As described above, according to the method of manufacturing an inkjet head of the present invention, the inkjet of the present invention can be performed by a simple method using a predetermined adhesive coating process, a first bonding process, a second bonding process, and a heat curing process. The head 1 can be manufactured.

FIG. 8 is a process diagram showing a fourth embodiment relating to a method of manufacturing an ink jet head according to the present invention. Here, a cross-sectional view of the liquid chamber unit in the direction of the short side of the liquid chamber is shown.
This embodiment is different from the second embodiment in that a partition wall 4 ′ having escape grooves 4a and 4b is used instead of the partition wall 4, and the other conditions are the same. Accordingly, here, the steps shown in FIGS. 8D and 8E will be described as differences from the second embodiment.

(S44) The nozzle plate 6 is arranged on the surface side of the partition wall 4 ′ to which the first adhesive 21a is applied, and the partition wall 4 ′ is applied to the surface side of the partition wall 4 ′ to which the second adhesive 22a is applied. The diaphragm 3 is disposed, and the nozzle plate 6 and the diaphragm 3 are bonded to the partition wall 4 ′ (FIG. 8 (d) bonding step). As a result, the first adhesive 21a is crushed between the nozzle plate 6 and the partition wall 4 ', and slightly protrudes toward the liquid chamber 5 like the cured resin 21 in the adhesive joint portion of FIG. In the present embodiment, the relief groove 4a is provided in the partition wall 4 ', so that the amount of protrusion is reduced even when the same amount of the first adhesive 21a is applied as compared with the second embodiment (FIG. 5). be able to. Further, the joining area is increased by the escape groove 4a, and sufficient adhesive strength can be obtained. Further, the second adhesive 22a is crushed between the diaphragm 3 and the partition wall 4 'and slightly protrudes toward the liquid chamber 5.

(S45) Heating is performed in a state where the partition wall 4 'is sandwiched between the diaphragm 3 and the nozzle plate 6, and the first adhesive 21a, the diaphragm 3 and the partition wall 4 at the bonded portion of the nozzle plate 6 and the partition wall 4' are combined. The second adhesive 22a in the bonded portion with 'is cured (heat curing step). Here again, the heating pattern, that is, the conditions of the temperature raising process, the heat curing process, and the slow cooling process are the same as those in the second embodiment (FIG. 5), and the phenomenon that occurs in each process is also the case of the second embodiment. Is the same. The relief groove 4a is formed on the side of the partition wall 4 'where the nozzle plate 6 is joined, so that the amount of protrusion of the first adhesive 21a is suppressed compared to the case where there is no relief groove (FIG. 5). Therefore, the portion of the first adhesive 21a in the bonded portion between the nozzle plate 6 and the partition wall 4 ′ that faces the inside of the liquid chamber 5 is smaller than that in FIG. The surplus portion of the moving second adhesive 22a can be relatively thickly covered.

  As described above, according to the method for manufacturing an ink jet head of the present invention, the ink jet head 1 of the present invention can be manufactured by a simple method by a predetermined adhesive coating process, a bonding process, and a heat curing process. It is.

Incidentally, a liquid tank for supplying a liquid such as ink to the above-described ink jet head of the present invention may be integrated to form a liquid cartridge.
FIG. 9 shows an external view of an ink cartridge that is the liquid cartridge. The ink cartridge 80 is obtained by integrating the above-described inkjet head 1 according to the present invention having the nozzle holes 6 a and the like, and an ink tank 82 that is a liquid tank that supplies ink to the inkjet head 1. Thus, in the case of the ink jet head 1 in which the ink tank 82 is integrated, the yield and reliability of the ink cartridge 80 can be improved by increasing the accuracy, density, and reliability of the actuator unit. The cost of the ink cartridge 80 can be reduced.

Next, the image forming apparatus according to the present invention will be described.
An image forming apparatus according to the present invention is an image forming apparatus that forms an image by ejecting droplets, and includes a liquid cartridge that is the above-described inkjet head of the present invention or the integrated inkjet head unit of the present invention. It is characterized by that.
Here, an ink jet recording apparatus which is an image forming apparatus equipped with the ink jet head 1 of the present invention will be described as an example with reference to FIGS. 10 and 11. 10 is a perspective explanatory view of the recording apparatus, and FIG. 11 is a side explanatory view of a mechanism portion of the recording apparatus.

  The ink jet recording apparatus includes a carriage 98 movable in the main scanning direction inside the recording apparatus main body, the ink jet head (recording head) 1 of the present invention mounted on the carriage 98, an ink cartridge 99 for supplying ink to the ink jet head 1, and the like. A paper feed cassette (or a paper feed tray) 93 on which a large number of sheets 92 can be stacked from the front side is detachably attached to the lower part of the apparatus main body. can do. Further, it has a manual feed tray 94 that is opened to manually feed the paper 92, takes in the paper 92 fed from the paper feed cassette 93 or the manual feed tray 94, and records a required image by the printing mechanism 91. Thereafter, the paper is discharged to a paper discharge tray 95 mounted on the rear side.

  The printing mechanism 91 holds a main guide rod 96, a sub guide rod 97, and a carriage 98, which are guide members horizontally mounted on left and right side plates (not shown), so as to be slidable in the main scanning direction. An inkjet head 1 that ejects ink droplets of each color (Y), cyan (C), magenta (M), and black (Bk) is arranged in a direction intersecting the main scanning direction with a plurality of ink ejection ports (nozzle holes 6a). However, it is mounted with the ink droplet ejection direction facing downward. In addition, each ink cartridge 99 for supplying ink of each color to the inkjet head 1 is replaceably mounted on the carriage 98.

  The ink cartridge 99 is provided with an air outlet communicating with the atmosphere at the upper side, and a supply port for supplying ink to the inkjet head 1 at the lower side, and has a porous body filled with ink inside. The ink supplied to the inkjet head 1 is maintained at a slight negative pressure by the capillary force of the body. Moreover, although the inkjet head 1 of each color is used as the inkjet head 1, it may be a single liquid discharge head having nozzle holes 6a for ejecting ink droplets of each color.

  Here, the carriage 98 is slidably fitted to the main guide rod 96 on the rear side (sheet conveyance downstream side), and the front side (sheet conveyance upstream side) is slidably mounted on the sub guide rod 97. Yes. In order to move and scan the carriage 98 in the main scanning direction, a timing belt 104 is stretched between a driving pulley 102 and a driven pulley 103 that are rotationally driven by the main scanning motor 101, and the timing belt 104 is moved to the carriage 98. The carriage 98 is reciprocally driven by forward and reverse rotations of the main scanning motor 101.

  On the other hand, in order to convey the paper 92 set in the paper feed cassette 93 downward to the inkjet head 1, the paper feed roller 105 and the friction pad 106 for separating and feeding the paper 92 from the paper feed cassette 93 and the paper 92 are guided. The guide member 107 to be transported, the transport roller 108 that reverses and transports the fed paper 92, the transport roller 109 pressed against the peripheral surface of the transport roller 108, and the feed angle of the paper 92 from the transport roller 108 are defined. A tip roller 110. The transport roller 108 is rotationally driven through a gear train by a sub-scanning motor.

  In addition, a printing receiving member 111 that is a paper guide member is provided to guide the paper 92 sent out from the transport roller 108 corresponding to the moving range of the carriage 98 in the main scanning direction on the lower side of the inkjet head 1. A conveyance roller 112 and a spur 113 that are rotationally driven to send the paper 92 in the paper discharge direction are provided on the downstream side of the printing receiving member 111 in the paper conveyance direction, and the paper 92 is further discharged to the paper discharge tray 95. A roller 114, a spur 115, and guide members 116 and 117 that form a paper discharge path are disposed.

  When recording with the inkjet recording apparatus 90, the inkjet head 1 is driven according to the image signal while moving the carriage 98, thereby ejecting ink onto the stopped sheet 92 to record one line, and then After the sheet 92 is conveyed by a predetermined amount, the next line is recorded. Upon receiving a recording end signal or a signal that the trailing edge of the paper 92 reaches the recording area, the recording operation is terminated and the paper 92 is discharged.

  Further, a recovery device 118 for recovering the ejection failure of the inkjet head 1 is disposed at a position outside the recording area on the right end side in the moving direction of the carriage 98. The recovery device 118 includes a cap unit, a suction unit, and a cleaning unit. During printing standby, the carriage 98 is moved to the recovery device 118 side, and the inkjet head 1 is capped by the cap means to keep the discharge port portion in a wet state, thereby preventing discharge failure due to ink drying. Further, by ejecting ink that is not related to recording during recording or the like, the ink viscosity of all the ejection ports is made constant and a stable ejection state is maintained.

  Further, when a discharge failure occurs, the discharge outlet (nozzle hole 6a) of the ink jet head 1 is sealed with a cap means, and bubbles with the ink are sucked out from the discharge outlet by the suction means through the tube, and the discharge outlet surface Ink, dust, etc. adhering to the ink are removed by the cleaning means, and the ejection failure is recovered. Further, the sucked ink is discharged to a waste ink reservoir (not shown) installed at the lower part of the main body and absorbed and held by an ink absorber inside the waste ink reservoir.

  As described above, since the ink jet recording apparatus 90 is equipped with the ink jet head 1 of the present invention, stable ink ejection characteristics can be obtained and the image quality can be improved. Although the case where the inkjet head 1 is used in the inkjet recording apparatus 90 has been described here, the inkjet head 1 may be applied to an apparatus that ejects droplets other than ink, for example, a liquid resist for patterning.

  In the present application, the “paper” is not limited to paper, but includes OHP, cloth, glass, a substrate, etc., and means a material to which ink droplets or other liquids can be attached. , Recording media, recording paper, recording paper, and the like. In addition, image formation, recording, printing, printing, and printing are all synonymous.

  The “image forming apparatus” means an apparatus that forms an image by discharging liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. “Formation” means not only giving an image having a meaning such as a character or a figure to a medium but also giving an image having no meaning such as a pattern to the medium (simply causing a droplet to land on the medium). ) Also means.

  The “ink” is not limited to an ink unless otherwise specified, but includes any liquid that can form an image, such as a recording liquid, a fixing processing liquid, or a liquid. Used generically, for example, includes DNA samples, resists, pattern materials, resins, and the like.

  In addition, the “image” is not limited to a planar image, and includes an image given to a three-dimensionally formed image and an image formed by three-dimensionally modeling a solid itself.

  Further, the image forming apparatus includes both a serial type image forming apparatus and a line type image forming apparatus, unless otherwise limited.

Examples of the present invention will be described below.
[Example A]
(Example A1)
A liquid chamber unit (bonding sample A) of the inkjet head 1 was produced under the following conditions.
(1) Member / diaphragm 3; Ni foil (thickness 27 μm, surface coated with polyimide resin)
・ Partition 4 ： Stainless steel sheet (thickness 40μm)
・ Nozzle plate 6; stainless steel thin plate (thickness 50 μm, surface coated with SiO ₂ by sputtering, used after the adhesive bonding surface was plasma treated)

(2) Adhesive (a) First adhesive 21a; obtained by blending the following chemicals.
-Main resin: bisphenol A type epoxy resin 100 parts by weight (trade name jER1010 (epoxy equivalent 3000-5000), manufactured by Mitsubishi Chemical Corporation)
Curing agent: 0.14 parts by weight of amine curing agent (trade name DICY7 (mainly dicyandiamine, manufactured by Mitsubishi Chemical Corporation)
-Solvent: 482.1 parts by weight of methyl ethyl ketone (MEK) (manufactured by Kanto Chemical Co., Inc.)
(B) Second adhesive 22a; obtained by blending the following agents.
・ Main resin: DCPD type epoxy resin 100 parts by weight (trade name EPICLON HP-7200HH, manufactured by DIC Corporation)
-Curing agent: Amine-based curing agent 3.39 parts by weight (trade name DICY7 (mainly dicyandiamine, manufactured by Mitsubishi Chemical Corporation)
-Solvent: 497.7 parts by weight of methyl ethyl ketone (MEK) (manufactured by Kanto Chemical Co., Inc.)

(3) Production Procedure A liquid chamber unit joined sample A was produced according to the production procedure shown in FIG. 5 (second embodiment of the method for producing an inkjet head according to the present invention).
The heating pattern in step S25 (heat curing step) is that the temperature is first gradually raised from room temperature to 175 ° C., then heated at that temperature for 7 hours, and then cooled to room temperature over 8 hours. did.
Here, the glass transition point of the main resin (jER1010) of the first adhesive 21a is around 140 ° C., and the softening point of the main resin (EPICLON HP-7200HH) of the second adhesive 22a is 15 ° C. Thus, both the first adhesive 21a and the second adhesive 22a showed fluidity in the temperature raising process. At this time, since the second adhesive 22a is applied in a larger amount than the first adhesive 21a and is applied after the first adhesive 21a, the nozzle plate is smooth due to its surface tension. A portion of the first adhesive 21 a at the bonding portion between the partition wall 6 and the partition wall 4 that faces the inside of the liquid chamber 5 was covered. At the same time, the solvent of each of the first adhesive 21a and the second adhesive 22a is volatilized by heating, but since both are the same solvent (MEK), it becomes difficult to separate the layers clearly, and the interface between the two Became ambiguous.
In the heat curing process, since the first adhesive 21a and the second adhesive 22a are the same curing agent (DICY7), the first adhesive 21a and the second adhesive 22a are cured at almost the same time. The main resin (epoxy resin) was cured as one cured resin. As a result, it became difficult to cause interface peeling between the cured resin 21 and the cured resin 23.

(Example A2)
A liquid chamber unit (joint sample B) of the inkjet head 1 was produced under the following conditions.
(1) Member / diaphragm 3; Ni foil (thickness 27 μm, surface coated with polyimide resin)
・ Partition 4 ： Stainless steel sheet (thickness 40μm)
・ Nozzle plate 6; stainless steel thin plate (thickness 50 μm, surface coated with SiO ₂ by sputtering, used after the adhesive joint surface was plasma treated)

(2) Adhesive (a) First adhesive 21a; obtained by blending the following chemicals.
-Main resin: bisphenol A type epoxy resin 100 parts by weight (trade name jER827 (epoxy equivalent 180-190), manufactured by Mitsubishi Chemical Corporation)
Curing agent: Amine-based curing agent 4 parts by weight (trade name DICY7 (mainly dicyandiamine, manufactured by Mitsubishi Chemical Corporation)
・ Solvent: 500.65 parts by weight of methyl ethyl ketone (MEK) (manufactured by Kanto Chemical Co., Inc.)
(B) Second adhesive 22a; obtained by blending the following agents.
・ Main resin: DCPD type epoxy resin 100 parts by weight (trade name EPICLON HP-7200HH, manufactured by DIC Corporation)
-Curing agent: Amine-based curing agent 3.39 parts by weight (trade name DICY7 (mainly dicyandiamine, manufactured by Mitsubishi Chemical Corporation)
-Solvent: 497.7 parts by weight of methyl ethyl ketone (MEK) (manufactured by Kanto Chemical Co., Inc.)

(3) Production Procedure A joined sample B of the liquid chamber unit was produced according to the production procedure shown in FIG. 4 (first embodiment of the method for producing an ink jet head according to the present invention).
The heating pattern in step S16 (heat curing step) is that the temperature is first gradually raised from room temperature to 175 ° C., then heated at that temperature for 7 hours, and then cooled to room temperature over 8 hours. did. Here, the main resin (jER827) of the first adhesive 21a is a liquid at room temperature, and the softening point of the main resin (EPICLON HP-7200HH) of the second adhesive 22a is 15 ° C. In FIG. 5, both the first adhesive 21a and the second adhesive 22a showed fluidity. At this time, since the second adhesive 22a is applied in a larger amount than the first adhesive 21a and is applied after the first adhesive 21a, the nozzle plate is smooth due to its surface tension. A portion of the first adhesive 21 a at the bonding portion between the partition wall 6 and the partition wall 4 that faces the inside of the liquid chamber 5 was covered. At the same time, the solvent of each of the first adhesive 21a and the second adhesive 22a is volatilized by heating, but since both are the same solvent (MEK), it becomes difficult to separate the layers clearly, and the interface between the two Became ambiguous.
In the heat curing process, since the first adhesive 21a and the second adhesive 22a are the same curing agent (DICY7), the first adhesive 21a and the second adhesive 22a are cured at almost the same time. The main resin (epoxy resin) was cured as one cured resin. As a result, it became difficult to cause interface peeling between the cured resin 21 and the cured resin 23.

(Comparative Example A1)
In Example A1, the second adhesive 22a is replaced with the first adhesive 21a, and the first adhesive 21a is applied to both surfaces of the partition wall 4, and the liquid chamber unit under the same conditions as in Example A1 except for the above. A bonding sample C was prepared.

(Comparative Example A2)
In Example A1, the first adhesive 21a is replaced with the second adhesive 22a, and the second adhesive 22a is applied to both surfaces of the partition wall 4, and the liquid chamber unit is used under the same conditions as in Example A1 except that. A bonding sample D was prepared.

(sample test)
The following evaluation was performed about the joining samples A to D obtained as described above.
(1) Measurement of peel strength after ink contact The bonded samples A, B, C, and D were immersed in the ink X shown below for 180 days while being heated to 60 ° C., and the bonded samples were taken out every predetermined number of days during the period. Then, the peel strength between the nozzle plate 6 and the partition 4 in the bonded sample was measured.
The peel strength was measured by performing a 90 ° peel test in the following procedure using a tensile tester and a dedicated jig.
(Procedure 1) The adhesion part between the nozzle plate 6 and the partition wall 4 at one end of the bonded sample is slightly peeled off.
(Procedure 2) The nozzle plate 6 is fixed to the pedestal, and the diaphragm 3 and the partition wall 4 peeled from the nozzle plate 6 are bent so that the plate surface is 90 ° with respect to the plate surface of the nozzle plate 6.
(Procedure 3) Using a tensile tester, the diaphragm 3 and the partition wall 4 are pulled at a speed of 1 mm / min so that the tensile direction is always 90 ° with respect to the plate surface of the nozzle plate 6, and the resistance force is peel strength. Measure as

(Ink X)
First, among the following components, each wetting agent, penetrant, surfactant and water are mixed and stirred for 1 hour to obtain a uniform mixed solution. Next, a coloring material and an antifoaming agent are added to this mixed solution and stirred for 1 hour, and then this dispersion is subjected to pressure filtration with a 0.8 μm cellulose acetate membrane filter to remove coarse particles and dust. Ink X used for evaluation.

(Ink X component)
Color material: Pigment resin dispersion (REGAL660R dispersion (manufactured by Cabot))
25.8 mass%
·solvent;
..Amid type wetting agent; N-methyl-2-pyrrolidone 25.0 mass%
..Alcohol-based wetting agent; glycerin 10.0 mass%
1,3-butanediol 5.0 mass%
・ Penetration agent: 1,2-hexanediol 2.0 mass%
・ Surfactant: BYK-348 (by Big Chemie) 1.0 mass%
・ Water 31.2mass%
(Total 100 mass%)

In FIG. 12, the measurement result of the peeling strength of a joining sample is shown.
As shown in FIG. 12, the bonding sample A of Example A1 (in the figure, ● plot) shows high peel strength before being immersed in ink X (initial peel strength), and the peel strength decreases during the test period. There was no. Further, the bonding sample B of Example A2 (in the figure, ■ plot) has a lower value than the bonding sample A, but showed a certain initial peel strength, and the value did not decrease during the test period.
On the other hand, the joint sample C of Comparative Example A1 (in the figure, ▲ plot) showed high initial peel strength, but the peel strength suddenly decreased after 3 weeks, and thereafter the peel strength gradually decreased. It was. Moreover, the joining sample D (x plot in the figure) of Comparative Example A2 showed extremely low peel strength from the initial stage, and its value did not change during the test period.

(2) Head Durability An ink jet head having the configuration shown in FIGS. 1 and 2 was produced using the joined samples A, B, C, and D, and each was designated as head samples A, B, C, and D. Next, the head samples A, B, C, and D are filled with the ink X and heated to 60 ° C. and stored for 180 days. The head samples A, B, C, and D are taken out every predetermined number of days during the period. The ink was discharged and the ink droplet discharge speed Vj was measured. The ink droplet ejection speed was measured by applying a pulse voltage of 7.6 V, frequency 30 Hz, waveform PULL to the electrodes (common electrode 10 and individual electrode 11) of the piezoelectric element 2 of the inkjet head at room temperature. Then, the ink X was discharged, and a moving image obtained by shooting the state of the discharge with a high-speed camera was frame-fed to obtain the discharge speed.

FIG. 13 shows the measurement results of the ink droplet ejection speed of the inkjet head samples (head samples A, B, C, and D).
Head samples A and B to which the joining samples of Examples A1 and A2 were applied (in the figure, ● and ■ plots) showed a stable and high discharge speed during the test period.
On the other hand, the head sample C to which the joining sample C was applied (in the figure, ▲ plot) showed a high ejection speed at the beginning, but the head sample C was broken during the ink filling to the head in the measurement on the 122nd day. Oops. In addition, the head sample D (× plot in the figure) to which the bonding sample D was applied was broken at the initial stage because it could not withstand the ink filling pressure.

[Example B]
(Example B1)
In Example A1, the partition wall 4 was replaced with a partition wall 4 ′ shown below, and a bonding sample E of a liquid chamber unit was produced under the same conditions as in Example A1 except that.
-Partition wall 4 ': Stainless steel thin plate (thickness 40 µm). In addition, the grinding | polishing process which grind | polishes one direction about each main surface was performed, and the relief grooves 4a and 4b were formed. The groove widths of the escape grooves 4a and 4b were 7 to 10 μm, and the groove depth was 2 to 5 μm.

(Example B2)
In Example A2, the partition wall 4 was replaced with the following partition wall 4 ′, and a liquid chamber unit bonded sample F was produced under the same conditions as in Example A2 except for the above.
-Partition wall 4 ': Stainless steel thin plate (thickness 40 µm). In addition, the grinding | polishing process which grind | polishes one direction about each main surface was performed, and the relief grooves 4a and 4b were formed. The groove widths of the escape grooves 4a and 4b were 7 to 10 μm, and the groove depth was 2 to 5 μm.

(sample test)
The following evaluation was performed on the bonding samples E and F obtained as described above and the bonding samples A and B manufactured in Example A.
(1) Measurement of peel strength after ink contact The joining samples A, B, E, and F were immersed in the ink X described above for 510 days while being heated to 70 ° C., and the joining samples were taken out every predetermined number of days during the period. The peel strength between the nozzle plate 6 and the partition wall 4 in the bonded sample was measured.
The peel strength was measured by performing a 90 ° peel test in the following procedure using a tensile tester and a dedicated jig.
(Procedure 1) The adhesion part between the nozzle plate 6 and the partition wall 4 at one end of the bonded sample is slightly peeled off.
(Procedure 2) The nozzle plate 6 is fixed to the pedestal, and the diaphragm 3 and the partition wall 4 peeled from the nozzle plate 6 are bent so that the plate surface is 90 ° with respect to the plate surface of the nozzle plate 6.
(Procedure 3) Using a tensile tester, the diaphragm 3 and the partition wall 4 are pulled at a speed of 1 mm / min so that the tensile direction is always 90 ° with respect to the plate surface of the nozzle plate 6, and the resistance force is peel strength. Measure as

In FIG. 14, the measurement result of the peeling strength of a joining sample is shown.
As shown in FIG. 14, the bonding sample E of Example B1 (♦ plot in the figure) shows high peel strength before being immersed in ink X (initial peel strength), and the peel strength decreases during the test period. There was no. Moreover, although the joining sample F (* plot in the figure) of Example B2 is a value lower than the joining sample E, it showed a certain initial peel strength, and the value did not decrease during the test period.
On the other hand, the bonding sample A of Example A1 (in the figure, ● plot) shows an initial peel strength slightly lower than that of the bonding sample E of Example B1, and thereafter, the peel strength gradually decreases. It was. Further, the bonding sample B of Example A2 (■ plot in the figure) shows a slightly lower initial peel strength than that of the bonding sample F of Example B2, and as in Example A1, the peel strength gradually decreases. It was.

(2) Head Durability An ink jet head having the configuration shown in FIGS. 1 and 2 was produced using the joining samples A, B, E, and F, and the head samples A, B, E, and F were used. Next, the head samples A, B, E, and F are filled with the ink X and heated to 70 ° C. and stored for 510 days. The head samples A, B, E, and F are taken out every predetermined number of days during the period. The ink was discharged and the ink droplet discharge speed Vj was measured. The ink droplet ejection speed was measured by applying a pulse voltage of 7.6 V, frequency 30 Hz, waveform PULL to the electrodes (common electrode 10 and individual electrode 11) of the piezoelectric element 2 of the inkjet head at room temperature. Then, the ink X was discharged, and a moving image obtained by shooting the state of the discharge with a high-speed camera was frame-fed to obtain the discharge speed.

FIG. 15 shows the measurement results of the ink droplet ejection speed of the inkjet head samples (head samples A, B, E, and F).
Head samples E and F to which the bonding samples of Examples B1 and B2 were applied (in the figure, ◆ and * plots) showed a stable and high discharge speed during the test period.
On the other hand, the head sample A (• plot in the figure) to which the bonding sample A was applied showed a high ejection speed at the beginning, but the head sample A was broken during the ink filling into the head in the measurement on the 320th day. Oops. In addition, in the head sample B to which the bonding sample B was applied (in the figure, the ■ plot), the head sample B was broken during ink filling into the head in the measurement on the 192th day.

  Although the present invention has been described with the embodiments shown in the drawings, the present invention is not limited to the embodiments shown in the drawings, and other embodiments, additions, modifications, deletions, etc. Can be changed within the range that can be conceived, and any embodiment is included in the scope of the present invention as long as the effects and advantages of the present invention are exhibited. That is, here, the type using the piezoelectric element 2 which is an electromechanical conversion element as the droplet discharge energy generating means of the inkjet head 1 has been described. However, as the other droplet discharge energy generating means, an electromechanical conversion element is used. A certain electrostatic actuator or a thermal type that is an electrothermal conversion element may be used.

DESCRIPTION OF SYMBOLS 1 Inkjet head 2 Piezoelectric element 3 Vibrating plate 4, 4 'Partition 4a, 4b Escape groove 5 Liquid chamber 6 Nozzle plate 6a Nozzle hole 7 Fluid resistance part 8 Common liquid chamber 9 Common ink supply port 10 Common electrode 11 Individual electrode 12 Piezoelectric Body 21, 22, 23 Cured resin 21a First adhesive 22a Second adhesive 80, 99 Ink cartridge 81 Ink tank 90 Inkjet recording device 91 Printing mechanism 92 Paper 93 Paper feed cassette 94 Manual feed tray 95 Paper discharge tray 96 Main guide rod 97 Subordinate guide rod 98 Carriage 101 Main scanning motor 102 Drive pulley 103 Driven pulley 104 Timing belt 105 Feed roller 106 Friction pad 107, 116, 117 Guide member 108 Conveying roller 109, 112 Conveying roller 110 Tip Roller 111 Printing receiving member 113, 115 Spur 114 Discharge roller 118 Recovery device

Japanese Patent Laid-Open No. 2-51734 JP-A-61-59911 Japanese Patent Laid-Open No. 6-71882 Japanese Patent Laid-Open No. 2002-210964 JP 11-188874 A

Claims (13)

A plurality of liquids partitioned by a nozzle plate provided with nozzles for ejecting ink, a substrate having a liquid discharge energy generating unit, and a partition wall provided between the nozzle plate and the substrate, each having the nozzle. In the inkjet head in which the chamber is formed,
Either one of the bonding surface of the nozzle plate and the bonding surface of the substrate bonded to the partition wall is formed of a metal material, the other is formed of a resin material,
The bonding surface of the metal material and the partition are bonded by a first adhesive containing an epoxy resin having a hydroxyl group in a molecular chain,
The bonding surface of the resin material and the partition wall are bonded by a second adhesive having a lower hygroscopicity than the first adhesive,
A portion of the bonding surface between the metal material bonding surface and the partition that faces the liquid chamber is caused by an excess of the second adhesive that bonds the resin material bonding surface and the partition. An inkjet head characterized by being coated. The nozzle plate is made of a metal material and is provided with a nozzle for discharging ink, a substrate having a liquid discharge energy generating unit, and a partition wall provided between the nozzle plate and the substrate, each of which has the nozzle. In an inkjet head in which a plurality of liquid chambers are formed,
The nozzle plate and the partition are bonded by a first adhesive containing an epoxy resin having a hydroxyl group in a molecular chain, and the substrate and the partition made of a resin material on the bonding surface are formed by the first adhesive. Is bonded with a low-hygroscopic second adhesive,
The adhesive bonding portion between the nozzle plate and the partition and the portion facing the liquid chamber is covered with an excess of the second adhesive that bonds the substrate and the partition. An inkjet head. It said nozzle plate, an ink jet head according to claim 2, characterized in that stainless steel, or the N i of a metallic material mainly.   4. The inkjet head according to claim 2, wherein a surface of the partition that adheres to the nozzle plate has an escape groove through which the first adhesive can flow. 5.   The inkjet head according to any one of claims 1 to 4, wherein the first adhesive includes any one of a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, and a bisphenol S type epoxy resin.   The second adhesive includes any one of a biphenyl type epoxy resin, a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, a dicyclopentadiene type epoxy resin, and a naphthalene type epoxy resin. The inkjet head according to any one of 5.   The inkjet head according to claim 1, wherein the first adhesive and the second adhesive contain an amine-based curing agent.   The inkjet head according to claim 1, wherein the first adhesive and the second adhesive contain the same curing agent.   The inkjet head according to claim 1, wherein the first adhesive and the second adhesive contain the same main solvent.   An image forming apparatus comprising the ink jet head according to claim 1. A plurality of liquids partitioned by a nozzle plate provided with nozzles for ejecting ink, a substrate having a liquid discharge energy generating unit, and a partition wall provided between the nozzle plate and the substrate, each having the nozzle. In the manufacturing method of the inkjet head in which the chamber is formed,
Forming either one of the bonding surface of the nozzle plate and the bonding surface of the substrate to be bonded to the partition wall as a metal material and the other as a resin material;
A first adhesive containing an epoxy resin having a hydroxyl group in the molecular chain is applied to one surface of the partition, and then the surface opposite to the one surface of the partition is less hygroscopic than the first adhesive. An adhesive application step of applying the second adhesive of
A first bonding step of bonding a surface of the partition wall to which the first adhesive is applied and a bonding surface formed of the metal material;
A second bonding step of bonding the surface of the partition wall to which the second adhesive is applied and the bonding surface formed of the resin material;
By heating, a first adhesive at a bonding portion between the bonding surface and the partition formed of the metal material, and a second adhesive at a bonding portion between the bonding surface and the partition formed of the resin material. A heat curing step for curing;
Have
In the heat curing step, at least the second adhesive is provided with fluidity in the heating temperature increasing process, and the second portion in the bonded portion between the bonding surface formed of the resin material and the partition wall is provided. The excess of the adhesive is the first adhesive of the bonded portion between the joining surface formed of the metal material and the partition wall and covers the portion facing the liquid chamber, and then heat-cured A method of manufacturing an inkjet head, wherein the first adhesive and the second adhesive are cured in the process. The nozzle plate is made of a metal material and is provided with a nozzle for discharging ink, a substrate having a liquid discharge energy generating unit, and a partition wall provided between the nozzle plate and the substrate, each of which has the nozzle. In a manufacturing method of an inkjet head in which a plurality of liquid chambers are formed,
A first adhesive containing an epoxy resin having a hydroxyl group in the molecular chain is applied to one surface of the partition, and then the surface opposite to the one surface of the partition is less hygroscopic than the first adhesive. An adhesive application step of applying the second adhesive of
A first bonding step of bonding the surface of the partition wall to which the first adhesive is applied and the nozzle plate;
A second bonding step of bonding the surface of the partition wall to which the second adhesive is applied and the substrate having a bonding surface made of a resin material;
A heat curing step of curing the first adhesive in the bonded portion between the nozzle plate and the partition by heating, and the second adhesive in the bonded portion between the substrate and the partition;
Have
In the heat curing step, at least the second adhesive is provided with fluidity in the heating temperature rising process, and the surplus of the second adhesive in the bonded portion between the substrate and the partition wall is, The first adhesive at the portion where the nozzle plate and the partition wall are bonded and the portion facing the inside of the liquid chamber is covered, and then the first adhesive and the second adhesive are bonded in the heat curing process. A method for producing an ink jet head, comprising curing an agent. The method of manufacturing an ink jet head according to claim 11, wherein the first bonding step and the second bonding step are performed simultaneously.