JP2019142213A - Ink-jet recording head and method for manufacturing the same - Google Patents

Abstract

To provide an ink-jet recording head using a material which can achieve both long-term ink resistance and a small coefficient of linear expansion as a flow channel member.SOLUTION: An ink-jet recording head 1000 includes a recording element substrate 1100 formed of Si, a liquid supply slit 1210, and a base plate 1200 for supporting a recording element substrate. The base plate 1200 is formed of a thermoset product of a solid epoxy resin composition containing an epoxy resin that is solid at normal temperature and a phenol resin that is solid at normal temperature and an alumina filler.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an inkjet recording head using an epoxy resin molded product and a method for manufacturing the same.

  An electromechanical transducer such as a piezo element is used as the energy generating element that generates energy for ejecting ink from the ejection port of the recording head of the ink jet recording apparatus. In addition, there are known ones that generate heat by irradiating an electromagnetic wave such as a laser and discharge ink droplets by the action of the heat generation, and those that heat a liquid by an electrothermal conversion element having a heating resistor.

  Among them, a recording head that uses thermal energy to discharge ink droplets (inkjet method) can arrange the discharge ports with high density, and therefore can perform high-resolution recording. Furthermore, among them, a recording head using an electrothermal transducer as an energy generating element can be easily downsized. Furthermore, recording heads using electrothermal transducers can make full use of the advantages of IC technology and micromachining technology, which have made remarkable progress in technology and reliability in recent semiconductor fields, and facilitate high-density mounting. This is advantageous because the manufacturing cost is low.

In order to perform recording with higher definition, a method for producing a nozzle for ejecting ink with high accuracy using a photolithography technique has been used. In recent years, in order to realize high-definition image recording at a higher speed, it is desired to realize a recording head having a longer recording width. Specifically, a recording head having a length of 4 inches to 12 inches or the like has been required.
In realizing a recording head having a long recording width as described above, in Patent Document 1, a plurality of recording element substrates having appropriate lengths are arranged on a base plate by having an appropriate number of nozzles. A configuration for realizing a recording head having a long recording width as a whole has been proposed. In this case, the base plate member that mounts the discharge pressure generating element and adds a flow path or the like is required to have a high flatness and a small linear expansion coefficient that does not generate stress with the Si substrate. Further, the base plate member is required to have high ink resistance. This is because if impurities or the like are dissolved in the ink, the discharge performance is adversely affected, and if it is severe, precipitates are generated and the nozzle is clogged.
A typical material having these characteristics is alumina.
However, molding large parts with alumina tends to be very expensive.
Therefore, in order to make the base plate member inexpensively, when the resin molding material described in Patent Document 2, Patent Document 3 or the like is used instead of alumina, the obtained ink jet recording head is in view of linear expansion and elution. It was not always satisfactory.
As a material, in consideration of chemical resistance, an epoxy resin is used, and a liquid composition is used in order to mix a large amount of filler. There was a need to increase. However, the material is in the form of fine granules or powder, and the epoxy resin and filler cannot be mixed uniformly. In addition, even if the material is mixed evenly without reducing the amount of filler, even if the material is mixed in a liquid state, the liquid resin is used. Go down. For this reason, rough skin where the resin and the filler are separated occurs, and the surface accuracy cannot be secured.

Japanese Patent Laid-Open No. 5-24192 JP 2011-173970 A JP 2009-155370 A JP2015-206209A

In Patent Document 4, the use of a molding material made of a liquid resin is described in order to solve the above problem, but the inkjet head is required to further improve long-term reliability and productivity for industrial applications and the like. When immersed in ink under extreme conditions such as long-term ink storage or pre-shear cooker tester (PCT), the thin skin on the filler will be peeled off, the filler will be exposed, and the filler may elute or fall off if severe. There is a case.
Accordingly, an object of the present invention is to provide an ink jet recording head in which a material capable of achieving both long-term ink resistance and a small linear expansion coefficient is used for a flow path member.

One embodiment of the present invention provides:
An ink jet recording head having a flow path member, wherein the flow path member is a thermosetting product of a solid epoxy resin composition containing an epoxy resin that is solid at room temperature and a phenol resin that is solid at room temperature, and an alumina filler It is related with the inkjet recording head characterized by being formed by these.
Another aspect of the present invention is a method for manufacturing an ink jet recording head, wherein the flow path member is a solid epoxy resin composition containing an epoxy resin that is solid at room temperature and a phenol resin that is solid at room temperature, and alumina. The present invention relates to a method for manufacturing an ink jet recording head, which is formed by injection molding a thermosetting molding material containing a filler.

  ADVANTAGE OF THE INVENTION According to this invention, the inkjet recording head which used the material which can make compatible long-term ink resistance and a small linear expansion coefficient for a flow-path member can be provided.

FIG. 1A is a side view and a bottom view showing an example of an ink jet recording head. FIG. 1B is an exploded perspective view illustrating an example of an ink jet recording head. FIG. 2 is a schematic diagram showing the injection molding machine used in the examples.

Hereinafter, embodiments of the present invention will be described with reference to the drawings for an ink jet recording head and a method for producing the same.
<Inkjet recording head>
FIG. 1A is a side view and a bottom view showing an example of an ink jet recording head 1000 to which the present invention can be applied. FIG. 1B is an exploded perspective view showing a component configuration of the ink jet recording head 1000 in FIG.
In the inkjet recording head 1000, nozzle rows are formed in a range that covers the maximum width of a sheet that is assumed to be used. This recording head is an ink jet type full-line recording head capable of wide recording without scanning the ink jet recording head.

  The ink jet recording head 1000 includes a recording element substrate 1100 made of Si, a liquid supply slit 1210, and a base plate 1200 for supporting the recording element substrate. The ink jet recording head 1000 further includes an electrical wiring substrate 1300 for electrical connection between the recording element substrate and the recording apparatus, a liquid storage unit 1510, and an ink supply member 1500 joined to the base plate 1200. The plurality of recording element substrates 1100 have ejection openings 1105 and are accurately arranged on the main surface 1200a of the base plate 1200 in a direction (Y direction) intersecting the recording medium conveyance direction (X direction). In FIG. 1B, the plurality of recording element substrates 1100 are alternately arranged in two rows so that the end portions 1109 of the ejection port group overlap each other. An ink supply member 1500 is disposed on a surface 1200b opposite to the main surface 1200a. The electrical wiring board 1300 includes electrode terminals 1320 and openings 1330.

Since the base plate 1200 forms a part of the flow path, the base plate 1200 needs to have high resistance to a liquid such as ink. For example, even if the material of the base plate is eluted to a liquid such as ink even if it is several ppm, the liquid such as ink evaporates in the vicinity of the ejection port, and deposits adhere to the vicinity of the ejection port. For this reason, deviation of the ejected liquid droplets or the like may occur, and printing defects may occur. Further, since the base plate 1200 is bonded to the recording element substrate 1100 formed of Si or the like by an adhesive or the like and high dimensional accuracy is required, the base plate 1200 preferably has a small linear expansion coefficient.
Therefore, in the present invention, the flow path member such as the base plate 1200 is used as the heat of a thermosetting molding material containing an epoxy resin that is solid at room temperature, a solid epoxy resin composition containing a phenol resin that is solid at room temperature, and an alumina filler. Form with hardened material.
The material according to the present invention is a material having a small linear expansion coefficient, excellent moldability, little elution into a liquid such as ink, and can be used for injection molding.

In this invention, it can be set as a granular molding material by making a resin component into a solid, and can be highly filled with a filler. Especially when an injection molding machine is used, the combination of solid epoxy resin and solid phenol resin has a relatively low melt viscosity and high wettability to alumina, so the filler surface is well adapted to the resin with the screw in the injection molding machine. Can be made. In particular, when a polyfunctional resin is used as the solid epoxy resin and the solid phenol resin, the crosslink density becomes higher, and the filler is more firmly bonded, so that it is difficult to fall off. Further, by using alumina as the filler, elution from the filler hardly occurs even if the resin skin is partially peeled off. Furthermore, by using a solid epoxy resin and a solid phenol resin, even when the melt viscosity is lowered and the filler content is increased, the fluidity during molding is good.
Hereinafter, the thermosetting molding material for molding the thermoset according to the present invention and each component will be described.

  The solid epoxy resin composition includes an epoxy resin that is solid at room temperature (hereinafter also referred to as solid epoxy resin), a phenol resin that is solid at room temperature as a curing agent (hereinafter also referred to as phenol curing agent), a curing accelerator, and a silane agent. Etc. The main epoxy resin and the phenol curing agent need to be solid, but the other additives may be liquid or solid. The epoxy resin generally added for the purpose of modification may be liquid or solid as required. The solid epoxy resin composition may be solid at room temperature, and preferably has a melting point of 50 ° C. or higher in consideration of storage stability and handling.

The solid epoxy resin is preferably solid at room temperature (15 to 35 ° C.) and having a melting point in the range of 50 to 120 ° C. Examples of solid epoxy resins include naphthalene skeleton type, cresol novolac type, triphenyl type, biphenyl type, dicyclopentadiene type, naphthol skeleton type, bisphenol novolac type, glycidylamine type, phenol biphenylene type, alicyclic epoxy, etc. It is done. These epoxy resins may be used alone or in combination of two or more.
Among solid epoxy resins, a polyfunctional epoxy resin can be suitably used from the viewpoint of ink resistance, adhesion to fillers, and molding tact. Among them, triphenyl type epoxy resin has a high glass transition point in combination with a phenol curing agent, and can form a molded product having excellent ink resistance, so that it can be optimally used as a flow path member. it can.

The solid phenol resin used as the curing agent is preferably solid at room temperature (15 to 35 ° C.) and having a melting point in the range of 50 to 120 ° C. Examples of the solid phenol resin include phenol novolak type, xylylene novolak type, bis A novolak type, triphenylmethane novolak type, biphenyl novolak type, dicyclopentadiene type and the like. These phenol resins may be used alone or in combination of two or more.
Among the solid phenol resins, a polyfunctional epoxy resin can be suitably used from the viewpoints of ink resistance, adhesion to a filler, and molding tact. In the present invention, by using a phenol resin as a curing agent, the wettability of the solid epoxy resin composition to the alumina filler is improved, the epoxy resin composition and the alumina filler are firmly bonded, and reliability is ensured for long-term storage of the ink. Can be obtained.

In the thermosetting molding material according to the present invention, if phenolic hydroxyl groups remain in the molded product after the thermosetting reaction, the ink resistance is lowered, so that the amount of epoxy needs to be increased. Therefore, the content of the solid epoxy resin and the solid phenol resin is such that the molar ratio of the epoxy group of the solid epoxy resin and the phenolic hydroxyl group of the solid phenol resin is in the range of 1.0: 0.7 to 1.0: 0.98. Preferably, the range is 1.0: 0.90 to 1.0: 0.98.
Moreover, the total content of the solid epoxy resin and the solid phenol resin in the thermosetting molding material is preferably 8 to 30% by mass, more preferably 9 to 15% by mass.

The solid phenol resin which is a curing agent is generally low in reactivity and is preferably used in combination with a curing accelerator. Moreover, the epoxy group which is not reacting with a phenolic hydroxyl group can also advance reaction by adding a hardening accelerator. For this reason, the molded product contains no unreacted components and has good ink resistance. Examples of the curing accelerator include imidazoles such as 2-ethyl-4-methylimidazole and 1- (2-cyanoethyl) -2-ethyl-4-methylimidazoleimidazoles, tertiary amines, and triphenylphosphines. Etc.
Further, the content of the curing accelerator in the thermosetting molding material is preferably 0.01 to 0.5% by mass, more preferably 0.1 to 0.3% by mass.

In the present invention, alumina filler is used because elution into the ink is suppressed and the linear expansion coefficient is small. The alumina filler is preferably spherical in order to suppress linear expansion and high filling, and in order to achieve close packing, it is preferable to combine those having different particle sizes. In order to achieve close packing, the particle size of the alumina filler having the larger average particle size is preferably 3 to 5 times the particle size of the alumina filler having the smaller average particle size. Moreover, it is preferable that the particle diameter of the alumina filler with a larger average particle diameter is 15-50 micrometers, and it is preferable that the particle diameter of the alumina filler with a smaller average particle diameter is 3-15 micrometers. The weight ratio of the alumina filler having a large average particle diameter and the small alumina filler is preferably large: small = 9: 1 to 6: 4. The overall average particle diameter is preferably 50 μm or less, and if it is larger than this, the filling of details may be deteriorated, or the fluidity at the time of molding may be deteriorated. Further, when the particle size is about 5 μm or less, the specific surface area increases and the curing characteristics become better, but the fluidity at the time of molding decreases. Therefore, the average particle diameter of the entire alumina filler is particularly preferably 10 to 30 μm. Here, the average particle diameter means the number average particle diameter.
The filling amount of the alumina filler in the thermoset is preferably as much as possible in consideration of ink resistance, linear expansion coefficient, and thermal conductivity, but is preferably 70 to 92% by mass and 85 to 91% by mass in view of moldability. More preferred.

  The alumina filler is preferably treated with a silane coupling agent in order to improve adhesion to the resin component. In this case, the amount of the silane coupling agent used is preferably 0.01 to 0.06 parts by mass, more preferably 0.02 to 0.04 parts by mass with respect to 100 parts by mass of the alumina filler. Examples of the silane coupling agent include γ-glycidoxypropyltrimethoxysilane, β- (3,4 epoxycyclohexyl) -ethyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and the like. It is done. Further, a titanate or aluminate coupling agent may be used. These silane coupling agents may be used alone or in combination of two or more.

  Next, regarding the molding material according to the present invention, examples and comparative examples will be described as examples. Unless otherwise specified, “part” is a mass unit.

<Manufacture of molding materials>
Molding materials 1 to 11 described in Table 1 and Table 2 were prepared. Specifically, the solid epoxy resin described in Table 1 and Table 2, the solid phenol resin as the curing agent, the curing accelerator (curing catalyst), and the flow improver were mixed in the blending amounts described in Table 1 and Table 2. Thereafter, the mixture was stirred while a small amount of filler was added. Mixing of each material was performed by mixing with a mixer, hot melt mixing with a heat roll, and a kneader, cooling and solidifying, pulverizing, and filtering to obtain a uniform particle size, thereby obtaining a molding material. The molding material was evaluated as follows. The results are shown in Table 1 and Table 2 together.
In addition, the process by the silane coupling agent of the alumina filler used as a filler was performed as follows.
10 kg of alumina filler was put into a Henschel mixer, and while stirring at 700 rpm, a solution consisting of 3 g of a silane coupling agent (product name: A-187, manufactured by Momentive Performance Materials) and 400 g of ethanol was added. Charge and stir for 5 minutes. Then, confirm that the whole is a uniform viscous solution, and add steam. Then, when the solvent was evaporated by steam, the rotational speed of stirring was set to 1400 rpm, held at 100 ° C. for 5 minutes, and then cooled to treat the alumina filler with the silane coupling agent.

<Injection moldability evaluation>
About each obtained molding material, injection molding was performed using the injection molding machine shown in FIG. 2, and the injection moldability in the case of injection molding was evaluated.
A molding material is charged from the hopper 21. The charged material is pushed out toward the mold 27 by the screw 22. The material is changed from a solid 24 to a sticky state 25 and a liquid state 26 and pushed into a high-temperature mold 27 as the material is pressed.
In the above injection molding process, whether or not each molding material can be injection molded as usual was observed and the injection moldability was evaluated. The results are shown in Table 1 or Table 2. In addition, the property after kneading in the table was confirmed by visual observation and finger touch.
The setting conditions of the injection molding machine are as follows. Using an injection molding machine (product name: EC75SXR, manufactured by Toshiba Machine), a 40 mm × 40 mm × 3 mm flat plate was molded under the condition of 175 ° C. for 2 minutes.

<Ink resistance evaluation>
The molded product molded by the above-described injection moldability evaluation was subjected to additional thermosetting at 180 ° C. for 8 hours, and an ink resistance test was performed as follows. About resin composition 9-11 of the comparative example, since injection molding was not able to be performed, the molded article obtained by performing compression molding was evaluated. Ink resistance can be evaluated for molded products immediately after molding, but phenol curing agents have relatively low curing reactivity, and it is also assumed that the reaction of the components of the molded products is not complete. Therefore, additional heating was performed in consideration of long-term ink resistance.

  The obtained molded article was immersed in a transparent ink for logistics (distribution ink for inkjet printer) (trade name: F850, manufactured by Canon Inc.) and heated at 121 ° C. for 10 hours by PCT. After air cooling to room temperature, the ICP emission analyzer was used to confirm the presence or absence of filler (inorganic matter) elution from the molded product into the ink, and the presence or absence of the filler from the molded product was also observed. About the molded product in which elution and drop-off were not observed, it was heated again at 121 ° C. for 250 hours with PCT as it was, and similarly, the presence or absence of filler elution and the presence or absence of filler removal were observed. The results are shown in Tables 1 and 2.

As for the molding materials 1-7 of an Example and the molding material 8 of a comparative example, the molded article was able to be obtained by injection molding as usual.
On the other hand, since the molding materials 9 to 11 of the comparative example are sticky, when the material is put into an injection molding machine, the material is clogged with the hopper 21 and molding cannot be performed in a normal state.

  In the molding materials 1 to 7 of the examples, since the polyfunctional material and the solid material are used, up to 121 ° C. and 10 hours, filler elution and dropping do not occur and good ink resistance is shown. In the molding materials 3 and 4 of the examples, a polyfunctional epoxy resin having a triphenyl skeleton is particularly used as the epoxy resin, and Tg is 185 ° C., which is 20 to 40 ° C. higher than other molding materials. Since the curing temperature of the mounting material used during manufacture is 180 ° C. even at a high temperature, the molding materials 3 and 4 of the examples are not subjected to stress due to a difference in linear expansion during the manufacture and have a high crosslinking density. Ink resistance is good. Furthermore, when the molding materials 3 and 4 of an Example observe the result of 250 hours at 121 degreeC, they are less filler fallen compared with another resin composition. In particular, in the molding material 4, since the silane coupling treatment was performed on the alumina filler and the adhesion was improved with respect to the resin component, the filler detachment was not observed and the ink resistance was particularly excellent.

In this example, the alumina filler is contained in a large amount of 90% by mass, and the thermal conductivity is about 5 W / mK. During printing, since the recording element substrate generates heat, it is necessary to release the heat. Particularly, in the case of an industrial inkjet head, since a large number of recording element substrates are arranged, the resin composition of this embodiment is effective from these points. It turns out that it has the characteristic.
Since the molding material 8 of the comparative example does not contain an alumina filler and the filler is filled with a large amount of fused quartz, the silica that appears on the surface is slightly eluted. If the amount of elution is large, it reprecipitates or reacts with the ink components to form a solid material, which causes ejection irregularity or non-ejection.
Moreover, in the molding materials 9-11 of a comparative example, since it has not fully adhered with the alumina, the filler has fallen off. The filler that has fallen off is carried along with the ink, stays in the ink flow path, increases the flow resistance, and in the worst case, it becomes a cause of ejection failure, that is, non-ejection.

1000 Inkjet recording head 1100 Recording element substrate 1105 Discharge port 1109 Discharge port group end 1200 Base plate 1210 Ink supply slit 1300 Electrical wiring substrate 1320 Electrode terminal 1330 Opening 1500 Ink supply member 1510 Ink storage member 21 Hopper 22 Screw 23 Heater 24 Material A
25 Material B
26 Material C
27 Mold 28 Molded product

Claims (10)

  An ink jet recording head having a flow path member, wherein the flow path member is a thermosetting product of a solid epoxy resin composition containing an epoxy resin that is solid at room temperature and a phenol resin that is solid at room temperature, and an alumina filler An ink jet recording head characterized by being formed of   The ink jet recording head according to claim 1, wherein the epoxy resin and the phenol resin are polyfunctional.   The inkjet recording head according to claim 1, wherein the epoxy resin and the phenol resin have melting points of 50 ° C. or more, respectively.   The inkjet recording head according to claim 1, wherein the alumina filler is treated with a silane coupling agent.   The inkjet recording head according to claim 1, wherein the flow path member is a base plate for supporting a recording element substrate.   The inkjet recording head according to claim 1, wherein the epoxy resin is a triphenyl type epoxy resin. The molar ratio of the epoxy group of the said epoxy resin and the phenolic hydroxyl group of the said phenol resin is the range of 1.0: 0.7-1.0: 0.98 in any one of Claims 1-6. The inkjet recording head described.   The inkjet recording head according to claim 1, wherein the content of the alumina filler is 70 to 92% by mass.   The inkjet recording head according to claim 1, wherein the content of the alumina filler is 85 to 91% by mass.   The method for producing an ink jet recording head according to claim 1, wherein the flow path member is a solid epoxy resin composition containing an epoxy resin that is solid at room temperature and a phenol resin that is solid at room temperature. A method for manufacturing an ink jet recording head, comprising: forming a thermosetting molding material containing a filler and an alumina filler by injection molding.