JP2003063001A - Ink jet recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To resolve the problem of a conventional ink jet recording head such as that the ejecting amount and the ejection speed of ink drops are lowered and fine and exact recording cannot be performed. SOLUTION: The ink jet recording head comprises a lower plate 2, at least two separation walls 3 placed apart from each other on the upper face of the lower plate 2, a diaphragm 4 placed on the upper face of the separation walls 3, side plates 5 to close the inner space formed of the lower plate 2, a pair of the separation walls 3 and the diaphragm 4, and a pressuring means provided at the diaphragm 4, wherein ink ejection ports 7 and an ink supply port 8 are provided at the lower plate 2 and/or the side plates 5, and ink in the inside of the space is made to be ejected from the ink ejection ports 7 by deforming the diaphragm 4 by a pressurizing means 6. At least one of the lower plate 2, the separation walls 3, the diaphragm 4 and the side plates 5 is bonded by an adhesive 10 which contains an inorganic material filler in a thermosetting resin, and the surface of the inorganic material filler is coated with a silane coupling agent of 0.05 to 0.5 wt.% to the inorganic material filler.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head mounted on a high precision ink jet recording apparatus used for printing characters and images.

[0002]

2. Description of the Related Art In recent years, with the spread of personal computers and the development of multimedia, the use of ink jet type recording devices has rapidly expanded as a recording device for outputting information to a recording medium.

An ink jet recording head (hereinafter referred to as a head) is mounted on such an ink jet type recording apparatus, and as the head, a vibrating plate forming an ink flow path filled with ink is used a piezoelectric element. There is known a piezoelectric head that is deformed by a pressurizing unit to mechanically pressurize ink in an ink chamber to eject ink droplets from an ink ejection hole.

As shown in FIG. 3, such a piezoelectric head has a lower plate 12 having ink ejection holes 17 for ejecting ink droplets, and a plurality of partition walls 13 arranged on the upper surface of the lower plate 12 at equal intervals. A diaphragm 14 disposed on the upper surface of the partition wall 13.
A lower plate 12, a side plate that closes an internal space formed by the partition walls 13 and the vibration plate 14, and a piezoelectric element 16 provided on the upper surface of the vibration plate 14.
2, the partition wall 13 and the vibrating plate 14 form an ink flow path 11 (see Japanese Patent Laid-Open No. 7-156385).

To eject ink droplets from this head,
By energizing the piezoelectric element 16 through a lead wire from an external drive circuit (not shown) and displacing the piezoelectric element 16, the vibration plate 14 is deformed, and at the same time, the ink in each ink flow path 11 is pressurized. Ink droplets are ejected from the ink ejection holes 17.

In this head, the partition wall 13 is formed on the upper surface of the lower plate 12, the vibrating plate 14 is formed on the upper surface of the partition wall 13, and the ink passage 1 formed by the lower plate 12, the partition wall 13 and the vibrating plate 14.
1. Adhesive 20 composed of a thermosetting resin with a side plate on the open end face of No. 1
It is manufactured by joining through.

However, the adhesive 20 made of this thermosetting resin is apt to flow into the ink flow path 11 because the viscosity once decreases during thermosetting, and when a part of the adhesive 20 flows into the ink flow path 11. However, there is a drawback in that a part of the ink flow path 11 is blocked and the flow of ink is restricted, and as a result, the ejection of ink droplets from the respective ink ejection holes 17 varies, and it is not possible to perform a clean recording. Was.

In order to solve the above-mentioned drawbacks, therefore, it has been proposed to add an inorganic filler to the adhesive 20 made of a thermosetting resin and mix it to prevent a decrease in viscosity of the adhesive 20 during thermosetting.

The adhesive 20 made of a thermosetting resin mixed with and mixed with the filler of the inorganic material has no viscosity decrease during thermosetting, so that it is effective that a part of the adhesive 20 flows into the ink flow path 11. Is prevented and, as a result, the ink flow path 1
The flow of ink in 1 can be made free.

[0010]

However, in order to prevent the viscosity of the adhesive 20 from being lowered, the inorganic filler to be added to and mixed with the adhesive 20 made of a thermosetting resin should be noted only in the mixing amount, the particle size and the like. However, no attention has been paid to metal elements such as Fe, Mg, and Ca, and alkali metal elements such as Na, Li, and K, which are contained as impurities in the inorganic material filler.
Alternatively, the alkali metal element was contained in an amount of 0.7% by weight or more in terms of oxide, based on the total weight of the inorganic filler.

Metal elements such as impurities and / or
Alternatively, the partition wall 13 is formed on the upper surface of the lower plate 12, and the diaphragm 14 is formed on the upper surface of the partition wall 13 by using a mixture of an inorganic material filler containing an alkali metal element added to an adhesive 20 made of a thermosetting resin. In addition, the lower plate 1 that forms the ink flow path 11
When 2, the partition wall 13, the diaphragm 14, and the side plate are bonded together, the metal element and / or the alkali metal element contained in the inorganic filler is eluted into the ink and cationized to evenly disperse the colorant in the ink. The negative charge of the existing dispersant is partially neutralized, and as a result, the colorant in the ink agglomerates, the viscosity of the ink increases, the flow of the ink deteriorates, and the ink ejection holes 17 The discharge amount and the discharge speed of the ink droplets discharged from the printer are reduced, and in the worst case, the ink discharge holes 17 are blocked and the ink cannot be discharged, which leads to a defect that accurate and clean recording cannot be performed. It

The present invention has been devised in view of the above-mentioned drawbacks, and an object thereof is to provide an ink jet recording head capable of stabilizing ink ejection speed and ejection amount, and performing clean, accurate and clear recording. is there.

[0013]

According to the present invention, there is provided a lower plate, at least two partition walls spaced apart from each other on an upper surface of the lower plate, a vibration plate disposed on an upper surface of the partition wall, and the lower plate. And a side plate that closes an internal space formed by a pair of partition walls and a vibration plate, and a pressurizing unit provided in the vibration plate, and the lower plate and / or the side plate is provided with an ink ejection hole and an ink supply hole. An ink jet recording head for ejecting ink from an ink ejection hole by pressurizing ink supplied to the internal space through an ink supply hole by deformation of the diaphragm by a pressurizing means, the lower plate, the partition wall, and the diaphragm. And at least one of the side plates is joined by an adhesive containing a thermosetting resin containing an inorganic filler, and the surface of the inorganic filler of the adhesive is 0.05 to 0. 5 weight And it is characterized in that it is coated with a silane coupling agent.

The thermosetting resin comprises an epoxy resin and a curing agent, and has an amino group at the α-position carbon in the reactive group chemically bonded to the epoxy resin of the silane coupling agent. To do.

Further, the ink jet recording head of the present invention is characterized in that the curing agent is an aliphatic polyamine and / or an alicyclic polyamine.

According to the ink jet recording head of the present invention, at least one of the lower plate, the partition wall, the vibrating plate and the side plate forming the internal space filled with ink is made of a thermosetting resin and the surface thereof is made of a silane coupling agent. Since it was joined with the adhesive containing the coated inorganic material filler,
The decrease in viscosity during heat curing of the adhesive is effectively prevented by the inorganic material filler, and a part of the adhesive does not flow into the internal space where ink is supplied or into the ink ejection holes, and as a result, inside the ink flow path. In addition, it is possible to make the ink flow freely in the ink ejection holes and evenly eject the ink droplets from the ink ejection holes to perform clear recording.

Further, since the surface of the inorganic material filler is coated with the silane coupling agent, the affinity between the thermosetting resin and the inorganic material filler is increased, and the surface of the inorganic material filler is protected by the thermosetting resin. Since it is uniformly coated, the metal element and / or the alkali metal element, which are impurities of the inorganic material filler, hardly elute into the ink, and the thermosetting resin is prevented from flowing into the ink flow path. Therefore, the flow of ink becomes smooth, and the amount of ink droplets and the ejection speed of ink droplets ejected from the ink ejection holes are kept constant, so that clear, accurate, and clear recording is always possible.

Further, according to the ink jet recording head of the present invention, the thermosetting resin comprises an epoxy resin and a curing agent, and the carbon at the α position in the reactive group chemically bonded to the epoxy resin of the silane coupling agent. Since it has an amino group, it is possible to significantly increase the affinity between the inorganic material filler and the epoxy resin in the thermosetting resin,
The flow of ink becomes smoother, and the amount of ink droplets ejected from the ink ejection holes and the ejection speed are kept constant, so that clear, accurate, and clear recording can be performed at all times.

Furthermore, since the curing agent is an aliphatic polyamine and / or an alicyclic polyamine, it has a chemical structure similar to the amino group of the silane coupling agent, so that the silane coupling agent during the curing reaction. The amino group portion of the epoxy resin is incorporated into the epoxy resin, the epoxy resin and the inorganic material filler are more firmly bound, and the metal element and / or the alkali metal element that is an impurity of the inorganic material filler may be eluted into the ink. As a result, the flow of ink becomes smooth, and the amount and speed of ink droplets ejected from the ink ejection holes are kept constant, so that clean, accurate, and clear recording can always be performed.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 (a) is a partially broken perspective view showing an embodiment of the ink jet recording head of the present invention, and FIG. 1 (b) is a partial sectional view taken along line XX of FIG. 1 (a). FIG. 1C is a partial cross-sectional view taken along the line YY of FIG.

An ink jet recording head (hereinafter referred to as a head) of the present invention has a lower plate 2 having an ink ejection hole 7 for ejecting an ink droplet as shown in FIG. An inner space formed by the plurality of partition walls 3 arranged in a plurality, the diaphragm 4 arranged on the upper surface of the partition wall 3, the lower plate 2, the partition walls 3 and the diaphragm 4 as an ink flow path 1.
It is composed of a side plate 5 having an ink supply hole 8 joined so as to close the open end surface of the ink flow path 1, and a pressure means 6 composed of a piezoelectric element provided on the upper surface of the vibrating plate 4.

The lower plate 2 is made of a metal material such as silicon, stainless steel, titanium, nickel, copper or aluminum alloy, glass, an aluminum oxide sintered body, a silicon oxide sintered body or an aluminum nitride sintered body. Made of ceramics or glass-ceramics, or highly elastic resin materials,
For example, when it is made of silicon, by adopting a silicon single crystal growth technique such as a floating zone (FZ) method or a pulling (CZ) method, and when it is formed of an aluminum oxide sintered body, aluminum oxide, An organic solvent and a solvent are added to and mixed with a raw material powder of silicon oxide, magnesium oxide, calcium oxide, etc. to prepare the raw material, and the raw material is molded into a predetermined shape by a press molding method, a tape molding method, etc. It is produced by firing at a temperature of 1000 ° C.

The lower plate 2 has a plurality of partition walls 3 bonded to the upper surface thereof along one side of the lower plate 2, and each partition wall 3
An ink flow path 1 is formed between the lower plate 2 and a side plate 5 described later, and an ink discharge hole 7 is formed in the lower plate 2 so as to communicate with each ink flow path 1.

The partition wall 3 is made of the same metal material as silicon, stainless steel, titanium, nickel, copper, aluminum alloy, glass, aluminum oxide sintered body, silicon oxide sintered body, nitriding material similar to the lower plate 2 described above. A plate material made of a ceramic such as an aluminum-based sintered body or glass ceramics, or a resin material having high elasticity and manufactured by the same method as that of the lower plate 2 described above is bonded to the upper surface of the lower plate 2 with an adhesive 10. By being fixed, it is formed at a predetermined position on the upper surface of the lower plate 2.

If the lower plate 2 and the partition wall 3 are formed of a highly elastic material such as silicon, even if the ink in the ink flow path 1 between the partition walls 3 is pressurized, the lower plate 2 and the partition wall 3 are formed. The partition wall 3 is elastically deformed, the pressure of the ink in the ink flow path 1 is reduced and the ejection efficiency of the ink drop is reduced, or the ink in the adjacent ink flow channel 1 is pressurized to eject an unnecessary ink drop. Can be effectively prevented.

Further, ink discharge holes 7 are formed in the lower plate 2 at positions corresponding to the respective partition walls 3, and the ink discharge holes 7 are formed on the lower plate 2 by laser processing such as excimer laser or YAG laser. It is formed into a predetermined shape by performing etching processing or the like.

As shown in FIG. 2, the ink discharge hole 7 includes a connection hole 7a for sending ink from the ink flow path 1 and a tapered hole 7b for stabilizing the ink droplet discharge direction by restricting the ink flow. It is preferable to be composed of Therefore, the lower plate 2 has a hole which becomes a tapered hole 7b formed by excimer laser or the like on a plate-like body made of highly workable polyimide, polysulfone or the like on the lower surface of the lower plate 2 made of the above-mentioned highly elastic material. Adhesive 10
It is preferable to bond them via.

Further, a vibration plate 4 is bonded to the upper surface of the partition wall 3 with an adhesive 10 so as to close the upper part of each ink flow path 1, and is formed by the lower plate 2, the partition wall 3 and the vibration plate 4. The internal space formed serves as the ink flow path 1.

The vibrating plate 4 is made of silicon, stainless steel, titanium, nickel, copper, similar to the lower plate 2 and the partition 3 described above.
The lower plate described above is made of a metal material such as an aluminum alloy, glass, a ceramic such as glass, an aluminum oxide sintered body, a silicon oxide sintered body, an aluminum nitride sintered body or the like, or a highly elastic resin material. A plate material manufactured by the same method as that of No. 2 is applied to the upper surface of the partition wall 3 with the adhesive 10
It is formed by adhesively fixing via.

Further, on the upper surface of the vibrating plate 4, a pressurizing means 6 composed of a piezoelectric element is bonded at a position corresponding to each ink flow path 1 via an adhesive agent 10, and the pressurization composed of the piezoelectric element is applied. The means 6 is, for example, lead zirconate titanate (PZT) and lead magnesium niobate (PZ) polarized in the thickness direction.
MN), lead nickel niobate (PNN), etc., has a structure in which electrodes 9 are attached to both sides of the piezoelectric ceramic, and the piezoelectric ceramic is expanded and contracted in the horizontal direction by energizing between the electrodes 9. The vibration plate 4 is deformed in accordance with
The ink droplets are ejected from the ink ejection holes 7 by pressurizing the ink in the ink flow path 1 by the deformation of.

The pressurizing means 6 may be any one that has a function of pressurizing the ink in the ink flow path 1 through the vibrating plate 4, and the electrodes 9 are attached to both surfaces of the above-mentioned piezoelectric ceramic. Not limited to the piezoelectric element, for example, as shown in FIG. 2, a first electrode 9a made of gold, platinum, or the like is provided on the lower surface of the vibration plate 4, and a second electrode made of gold, platinum, or the like is provided above the vibration plate 4 with a certain interval. Electrode 9
b is placed in advance, electricity is applied between the electrodes 9a and 9b, and the first
The diaphragm 9 may be deformed by moving the electrode 9a to the second electrode 9b side or the second electrode 9b to the first electrode 9a side by electrostatic force. Further, the diaphragm 4 may be deformed by using a laminated piezoelectric element in which a plurality of layers of the piezoelectric ceramic used for the pressurizing means 6 and the electrode 9 are laminated.
Also in this case, similarly to the case of the piezoelectric element, by deforming the vibrating plate 4, it is possible to pressurize the ink supplied into the ink flow path 1 to eject an ink droplet from the ink ejection hole 7.

Further, a side plate 5 is joined to the open end surface of each ink flow path 1 with an adhesive 10, and an ink supply hole 8 communicating with each ink flow path 1 is formed in the side plate 5. ing.

The side plate 5 is made of the same metal material as silicon, stainless steel, titanium, nickel, copper, aluminum alloy, etc., glass, aluminum oxide sintered body, and oxidization similar to the lower plate 2, partition wall 3, and diaphragm 4 described above. Ceramics such as silicon-based sintered body, aluminum nitride-based sintered body or glass ceramics,
Alternatively, a plate material made of a highly elastic resin material or the like and manufactured by the same method as that of the lower plate 2 described above is bonded to the open end surface of the ink flow path 1 formed by the lower plate 2, the partition walls 3 and the diaphragm 4. It is formed by adhesively fixing via the agent 10.

In the present invention, the adhesive 10 for joining the lower plate 2 and the partition wall 3, the adhesive 10 for joining the partition wall 3 and the diaphragm 4, the lower plate 2, the partition wall 3 and the diaphragm 4 are used. As an adhesive 10 for joining the open end surface of the ink flow path 1 and the side plate 5 formed, a thermosetting resin contains an inorganic material filler, and the surface of the inorganic material filler is 0 relative to the inorganic material filler. It is important that the silane coupling agent is coated in an amount of 0.05 to 0.5% by weight.

Inorganic fillers added and mixed in the adhesive 10 include alumina (AL ₂ O ₃ ), silicon carbide (SiC), silica (SiO ₂ ), silicon nitride (Si ₃ ).
N ₄ ), glass fiber or the like having at least one of them as a main component is used, and alumina (AL ₂ O ₃ ), silicon carbide (SiC) and silica (SiO ₂ ) can be more preferably used.

When the average particle size of the inorganic filler is 10 nm to 8 μm and the maximum particle size is 1 to 20 μm, the lower plate 2 and the partition wall 3, the partition wall 3 and the vibrating plate 4, the lower plate 2, and the partition wall. When the open end surface of the ink flow path 1 formed by the vibration plate 3 and the vibrating plate 4 and the side plate 5 are joined, the inorganic material filler is filled to the closest density so that the thickness of the adhesive 10 is constant and each joining is made uniform. It can be made strong. Therefore, the inorganic filler has an average particle size of 10 nm to
It is preferable that the maximum particle size is 8 μm and the maximum particle size is 1 to 20 μm.

Further, the content of the inorganic filler is preferably 5 to 50% by volume. This content is 5% by volume
If it is less than the above range, it is not possible to effectively prevent a decrease in viscosity of the adhesive 10 during thermosetting, and there is a risk that part of the adhesive 10 may flow into the ink flow path 1. on the other hand,
When it exceeds 50% by volume, the absolute amount of the thermosetting resin decreases, and the ink flow path formed by the lower plate 2 and the partition 3, the partition 3 and the diaphragm 4, the lower plate 2, the partition 3 and the diaphragm 4. There is a risk that it will be difficult to firmly bond the open end face of No. 1 and the side plate 5 together.

In order to add and mix the inorganic material filler to the thermosetting resin, a mixing and stirring device using centrifugal force or a mixing and stirring device such as a homogenizer can be used to achieve uniform mixing. .

As the thermosetting resin, phenol resin, epoxy resin, melamine resin and the like are used.

If the thermosetting resin containing the inorganic filler is used as the adhesive 10 as described above,
The decrease in viscosity of the adhesive 10 during thermosetting is effectively prevented by the inorganic filler, and a part of the adhesive 10 is partially removed from the ink flow path 1.
As a result, it is possible to freely flow the ink in the ink flow path 1 and evenly eject ink droplets from the ink ejection holes 7 to perform clear recording.

Further, it is preferable that the thermosetting resin comprises an epoxy resin as a curing agent, and that the reactive group chemically bonded to the epoxy resin of the silane coupling agent has an amino group at the α-position carbon.

Since the epoxy resin has excellent heat resistance and water resistance, it becomes an insoluble and infusible thermosetting resin after curing, and since it does not contain volatile matter, it remains in contact with ink for a long time. Also, swelling hardly occurs, and ink does not leak or elute into the ink due to swelling, so that stable ink ejection can be performed for a long time.

The curing agent for the epoxy resin is preferably an aliphatic polyamine and / or an alicyclic polyamine. After curing the thermosetting resin, a silane-based curing agent is used as a part of the chemical structure of the epoxy resin. By incorporating the amino group of the coupling agent, it becomes possible to more firmly bond the inorganic material filler and the epoxy resin. And
A metal element or an alkali metal element as an impurity contained in the inorganic material filler can be prevented from eluting into the ink, and the ejection amount and ejection speed of ink droplets ejected from the ink ejection holes 7 can be stabilized. it can.

As the aliphatic polyamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, etc. can be used, and as the alicyclic polyamine, mensendiamine, isophoronediamine, N-aminoethylpiperazine, etc. Can be used.

The content of the metal element and / or the alkali metal element in the inorganic filler is measured by fluorescence X
It can be quantified using a linear analysis method.

Here, the surface of the inorganic filler is
It is important that the inorganic material filler is coated with 0.05 to 0.5% by weight of a silane coupling agent.

By coating the surface of the inorganic filler with a silane coupling agent, it is possible to effectively prevent the metal element and / or the alkali metal element contained as an impurity in the inorganic filler from being eluted into the ink.
The affinity between the thermosetting resin and the inorganic filler can be increased. Further, since the silane coupling agent has a wide range of degrees of freedom in chemical structure, the silane coupling agent can be appropriately selected depending on the type of the inorganic filler and does not contain an element that may be eluted into the ink. The agent is specified as a silane coupling agent.

If the content of the silane coupling agent is less than 0.05% by weight, the surface of the inorganic material filler is not uniformly coated with the thermosetting resin, so that the metal element or alkali contained in the inorganic material filler is not used. The metal element easily elutes in the ink, and the affinity between the surface of the inorganic material filler and the thermosetting resin becomes low. On the other hand, if it exceeds 0.5% by weight, the silane coupling agent becomes excessive, and the viscosity of the thermosetting resin mixed with the inorganic filler is extremely lowered, and the adhesive 10 flows into the ink flow path 1. As a result, the ejection of the ink droplets from the ink ejection holes 7 varies, and it becomes impossible to perform clear recording. Therefore, the content of the silane coupling agent is specified to be 0.05 to 0.5% by weight with respect to the inorganic filler.

Further, this silane coupling agent has a reactive group (OR) chemically bonded to an inorganic material bonded to Si and a reactivity to an organic material, as shown in the following chemical formula 1.
It is preferable that the reactive group having high solubility contains an amino group (NH ₂ ), and the amino group is bonded to carbon (C) existing at the α position of the reactive group with respect to an organic substance.

[0051]

[Chemical 1]

The amino group which is an organic reactive group of the silane coupling agent is easily bonded to an epoxy resin which is a thermosetting resin, and an aliphatic amine, an alicyclic amine, which is used as a curing agent for the epoxy resin, the chemical structure for forming the ester bond with tertiary amines and aromatic amines having an amino group structure chemical bonding, which is used for the acid anhydride of the general curing reaction accelerator, -NR ₃ The amino group is incorporated as a part of the reaction system during the curing reaction of the thermosetting resin, and thus the affinity with the epoxy resin is increased and a stronger bond can be formed. .

As the silane coupling agent having the above structure, α-aminopropyltrimethoxysilane, α-aminopropyltriethoxysilane, N-β
(Aminoethyl) -α-aminopropylmethyldimethoxysilane or the like can be used.

In order to eject ink droplets from the above-described head, first, an external driving circuit is energized to the pressurizing means 6 composed of a piezoelectric element or the like via a lead wire to drive the pressurizing means 6 composed of a piezoelectric element or the like. When it is deformed and one side of the diaphragm 4 is pulled,
The vibration plate 4 is deformed so as to bend downward into the ink flow path 1. Along with this, the pressure of the ink in the ink flow path 1 rises, a constant amount of ink flows out from the ink ejection hole 7 at a high speed, and the surface tension of the ink causes the ink ejected from the ink ejection hole 7 to drop. This is done by forming drops.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, in the above-described embodiment, the lower plate 2 and the partition wall are used. The lower plate 2 and the partition wall 3 may be integrally formed, though the lower plate 2 and the partition wall 3 are separately formed and joined by the adhesive 10. Further, in the above-described embodiment, the ink discharge holes 7 are formed in the lower plate 2.
Although the ink supply hole 8 is provided in the side plate 5, the ink discharge hole 7 and the ink supply hole 8 may be provided in either the lower plate 2 or the side plate 5, respectively. The holes 8 may be provided in the same lower plate 2, side plate 5 or the like.

[0056]

EXAMPLES Example 1 First, as shown in FIG. 1, a lower plate made of silicon was prepared, and epoxy resin contained metal elements or alkali metal elements as impurities shown in Table 1 on its upper surface. Add and mix various inorganic fillers,
A plurality of partition walls made of silicon are bonded to each other via an adhesive agent using triethyltetramine, which is an aliphatic polyamine as a curing agent, and a diaphragm made of stainless steel is attached to the upper surface of the partition walls, and lead zirconate titanate (PZT A pressure means using a piezoelectric ceramic mainly composed of (1) is joined via an adhesive made of a thermosetting resin such as epoxy to manufacture a head having a width of the ink flow path of 120 μm and a depth of 300 μm. .

Sample No. Nos. 2 to 6 and 8 to 12 have the inorganic material filler in the adhesive coated on the surface with a silane coupling agent as shown in Table 1.

After filling each of the obtained heads with a water-based ink, the ink ejection holes were closed with a silicone rubber cap and left at 70 ° C. for 4 weeks, and then the water-based ink was collected. The viscosity measurement was confirmed.

Further, by applying a driving frequency of 12 kHz and a voltage of 30 V to the pressurizing means using the piezoelectric ceramic, pressure is applied to the ink flow path to eject ink droplets, and the ink ejection speed is controlled by a high-speed video camera and a strobe. It was used to measure and calculate the trajectory of the ink droplet.

Sample No. Sample Nos. 1, 7, and 13 are comparative samples for comparison with the present invention. 1 and 7 do not contain a silane coupling agent, sample N
o. No. 13 does not add and mix the inorganic filler.

The contents of the metal element and the alkali metal element in the inorganic material filler were quantified by fluorescent X-ray analysis.

The above results are shown in Table 1.

[0063]

[Table 1]

As is clear from Table 1, the surface of the inorganic filler in the adhesive 10 was surface-treated with 0.05 to 0.5% by weight of a silane coupling agent (No.
3-5, 9-11) has an ink ejection speed of 5.8 m even if the metal element and / or the alkali metal element is in an amount close to 0.5% by weight based on the total weight of the inorganic material filler in terms of oxide. It has been found that stable ink ejection is possible by maintaining above / sec.

On the other hand, the sample containing no silane coupling agent and the sample containing less than 0.05% by weight (No.
1, 2, 7, 8), it was found that the viscosity of the ink increased and the ejection speed of the ink decreased to 5.0 m / sec or less.

The sample (No. 6, 12) to which the silane coupling agent was added in an amount of more than 0.5% by weight was used in the ink containing the metal element and / or the alkali metal element contained in the inorganic filler. Although the viscosity of the ink did not increase due to the elution to the ink, the silane coupling agent became excessive, the viscosity of the epoxy resin decreased, and the viscosity of the epoxy resin flowed into the ink flow path 1. Therefore, the ink discharge speed significantly decreased. I knew that. Example 2 An ink jet recording head sample similar to that of Example 1 was prepared.

A lower plate made of silicon was prepared, and an adhesive 10 was added on the upper surface of the epoxy resin with various inorganic material fillers containing metal elements or alkali metal elements as impurities shown in Table 2 contained therein. A plurality of partition walls made of silicon were joined together.

For the epoxy resin, α-aminopropyltrimethoxysilane, α-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and
An inorganic filler whose surface was coated with four types of silane coupling agents of γ-aminopropyltriethoxysilane was added and mixed, and triethyltetraamine, an aliphatic polyamine, was used as a curing agent.

Then, the ink viscosity of the head and the ink ejection speed were measured and evaluated in the same manner as in Example 1, and in order to confirm the action of the silane coupling agent, the inorganic substance in the adhesive 10 was confirmed. The state of the material filler was observed with an electron microscope.

The above results are shown in Table 2.

[0071]

[Table 2]

As is clear from Table 2, the sample (N with the silane coupling agent having an amino group at the α position was used).
o. Nos. 14 to 17 and 22 to 25), the inorganic material filler in the epoxy resin cured product is uniformly dispersed without increasing the ink viscosity, and the rigidity of the epoxy resin cured product is kept high, so that ink ejection is performed. Speed is 5.8m / sec
It turned out that it was above.

On the other hand, samples using the silane coupling agent having an amino group at the γ position (No. 18 to 2)
1, 27 to 30), the inorganic filler in the cured epoxy resin was aggregated, and it was confirmed that the epoxy resin flowed into the flow channel and was cured, and the ink ejection speed was 5.5 m / sec or less. It turns out that (Embodiment 3) Next, the same ink jet recording head samples as in Embodiments 1 and 2 are obtained, a lower plate made of silicon is prepared, and an epoxy resin is provided on the upper surface of the lower plate as shown in Table 3 and a metal element as an impurity in the epoxy resin. And various inorganic material fillers containing alkali metal elements are coated on the surface with α-aminopropyltrimethoxysilane and mixed,
A plurality of partition walls made of silicon were bonded through an adhesive 10 using triethyltetraamine, an aliphatic polyamine, N-aminoethylpiperazine, an alicyclic polyamine, and methyltetrahydrophthalic anhydride, an acid anhydride, as a curing agent. .

Then, the viscosity of the ink in the head and the ejection speed of the ink were measured and evaluated in the same manner as in Example 1, and in order to confirm the action of the silane coupling agent, the inorganic substance in the adhesive 10 was confirmed. The state of the material filler was observed with an electron microscope.

The above results are shown in Table 3.

[0076]

[Table 3]

As is clear from Table 3, samples using the aliphatic polyamine triethyltetraamine and the alicyclic polyamine N-aminoethylpiperazine as curing agents (N
o. 14, 15, 31, 32), the affinity between the epoxy resin and the filler of the inorganic material was further increased, the filler of the inorganic material was uniformly dispersed, and the ink ejection speed was 5.8 m / sec or more.

On the other hand, a sample using the acid anhydride methyltetrahydrophthalic anhydride as a curing agent (No. 3)
No. 3,34), the ink discharge speed was slightly decreased, and the inorganic filler was slightly aggregated.

[0079]

According to the ink jet recording head of the present invention, at least one of a lower plate, a partition wall, a vibrating plate and a side plate forming an internal space filled with ink is made of a thermosetting resin containing an inorganic material filler. Since the adhesive is used for bonding, the decrease in viscosity during thermosetting of the adhesive is effectively prevented by the inorganic filler, and part of the adhesive does not flow into the internal space where ink is supplied or into the ink ejection holes. As a result, the ink flow in the ink flow path and the ink ejection holes can be freely set, and the ink droplets can be uniformly ejected from the ink ejection holes to perform clear recording.

In addition, since the surface of the inorganic material filler is coated with the silane coupling agent, the affinity between the thermosetting resin and the inorganic material filler is increased, and the surface of the inorganic material filler is protected by the thermosetting resin. Since it is uniformly coated, the metal element and / or the alkali metal element, which are impurities of the inorganic material filler, hardly elute into the ink, and the thermosetting resin is prevented from flowing into the ink flow path. Therefore, the flow of ink becomes smooth, and the amount of ink droplets and the ejection speed of ink droplets ejected from the ink ejection holes are kept constant, so that clear, accurate, and clear recording is always possible.

Further, according to the ink jet recording head of the present invention, the thermosetting resin comprises an epoxy resin and a curing agent, and the carbon at the α position in the reactive group chemically bonded to the epoxy resin of the silane coupling agent. Since it has an amino group, it is possible to significantly increase the affinity between the inorganic material filler and the epoxy resin in the thermosetting resin,
The flow of ink becomes smoother, and the amount of ink droplets ejected from the ink ejection holes and the ejection speed are kept constant, so that clear, accurate, and clear recording can be performed at all times.

Further, since the curing agent is an aliphatic polyamine and / or an alicyclic polyamine, it has a chemical structure similar to the amino group of the silane coupling agent, so that the silane coupling agent during the curing reaction. The amino group portion of the epoxy resin is incorporated into the epoxy resin, the epoxy resin and the inorganic material filler are more firmly bound, and the metal element and / or the alkali metal element that is an impurity of the inorganic material filler may be eluted into the ink. As a result, the flow of ink becomes smooth, and the amount and speed of ink droplets ejected from the ink ejection holes are kept constant, so that clean, accurate, and clear recording can always be performed.

[Brief description of drawings]

1A is a perspective view showing an embodiment of an ink jet recording head of the present invention, FIG. 1B is a partial cross-sectional view taken along line XX of FIG. 1A, and FIG. (A) Y
It is a fragmentary sectional view in the -Y line.

FIG. 2 is a partial cross-sectional view showing another embodiment of the inkjet recording head of the present invention.

FIG. 3 is a partial cross-sectional view showing an embodiment of a conventional inkjet recording head.

[Explanation of symbols]

1: Ink flow path 2: Lower plate 3: Partition wall 4: Vibration plate 5: Side plate 6: Pressurizing means 7: Ink ejection hole 8: Ink supply hole 9: Electrode 10: Adhesive

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09J 11/04 B41J 3/04 103A 163/00 103H 201/00 F term (reference) 2C057 AF23 AF42 AG44 AG54 AP25 BA03 BA14 BA15 4J036 AA01 DC06 DC09 FA01 JA06 4J037 AA17 AA18 AA24 CB23 DD05 EE03 FF15 4J040 EB031 EB131 EC001 HA136 HA296 HA306 HC02 HC08 JB02 KA07 KA16 KA42 MA02 MA04 MA05 MA10 NA19 NA21

Claims (3)

[Claims] 1. A lower plate, at least two partition walls that are spaced apart from each other on an upper surface of the lower plate, a diaphragm that is disposed on an upper surface of the partition wall, the lower plate, a pair of partition walls, and a diaphragm. And a pressurizing means provided on the vibrating plate. The lower plate and / or the side plate is provided with an ink ejection hole and an ink supply hole, and the ink is supplied through the ink supply hole. An ink jet recording head which ejects ink from an ink ejection hole by pressurizing ink supplied to an internal space by deformation of a vibrating plate by a pressurizing means, wherein at least one of the lower plate, partition wall, vibrating plate and side plate is thermoset. Bonded with an adhesive containing an inorganic material filler in a hydrophilic resin, and the surface of the inorganic material filler is covered with a silane coupling agent in an amount of 0.05 to 0.5% by weight based on the inorganic material filler. It And an ink jet recording head, characterized in that it is. 2. The thermosetting resin comprises an epoxy resin and a curing agent, and has an amino group at the α-position carbon in the reactive group chemically bonded to the epoxy resin of the silane coupling agent. The inkjet recording head according to claim 1. 3. The ink jet recording head according to claim 2, wherein the curing agent is an aliphatic polyamine and / or an alicyclic polyamine.