JP3182882B2 - Ink jet head and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head for a printing apparatus in information equipment or the like, and more particularly to an ink jet head for generating so-called small ink droplets for recording.

[0002]

2. Description of the Related Art An ink jet head applied to an ink jet recording system generally includes a fine ink discharge port (orifice), an ink passage and a part of the ink passage, or an ink discharge pressure generating portion provided outside the base. It has. Conventionally, as a method of manufacturing such an ink-jet head, for example, fine grooves formed by cutting or etching a glass, silicon or metal plate, or fine grooves formed by exposing and developing a photosensitive resin, There is a method of forming an ink passage by bonding with an appropriate plate. Further, there has been known a method of forming an ink passage between the grooves or between the grooves with an intermediate substrate interposed therebetween.

[0003]

However, in the ink jet head manufactured by such a conventional method, when cutting or etching is performed, the roughness of the inner wall surface of the ink passage is too large, and the ink having a desired size is formed due to a difference in etching or the like. It is difficult to obtain a passage, and the ink ejection characteristics of the manufactured inkjet head tend to vary. In addition, there is a disadvantage that the plate is easily chipped or cracked at the time of cutting, and the production yield is poor.

In the case where a photosensitive resin is used, the joint between the substrate and the photosensitive resin or the photosensitive resin itself is attacked by the contact of the ink, causing swelling and peeling, so that long-term reliability cannot be ensured. . Further, conventionally, since an organic solvent developing type photosensitive resin containing a chlorinated solvent such as 1.1.1-trichloroethane is used to enhance ink resistance, there is a problem that the environment may be adversely affected. ing.

An object of the present invention is to solve the problems of the prior art and to provide an ink jet head having high yield and high reliability.

[0006]

According to the present invention, there is provided an ink jet head comprising a first photosensitive resin cured film having a pattern formed in a single layer or a plurality of layers on a substrate having an ink discharge port by using photosensitivity. A cured film of a second photosensitive resin in which a pattern is formed in a single layer or a plurality of layers using photosensitivity on a second substrate, and a cured film of the first photosensitive resin and the second film. In an ink jet head in which an ink passage is formed by laminating and joining the cured films of the photosensitive resin so that the cured film surfaces thereof are on the inside, an ink contact portion and a joint of the cured films of the first and second photosensitive resins are formed. The portion is covered with a uniform thin film made of a photosensitive resin having ink resistance different from that of the first and second photosensitive resins. Further, the photosensitive resin having ink resistance is a photosensitive urethane acrylate resin. An energy generating element for generating energy used for discharging ink at a position opposite to a surface of the second substrate on which a cured film of a photosensitive resin is formed and below an ink discharge port. Is provided. Further, the energy generation element is a piezoelectric element. Further, the photosensitive resin of the patterned photosensitive resin cured film is of an aqueous (including a weakly alkaline aqueous solution) developing type. Further, the member forming the ink passage is an engineering plastic. Further, the photosensitive region of the photosensitive resin member and the ink-resistant photosensitive resin has a photosensitive region of two or more wavelengths from an electron beam to an infrared ray. Further, the photosensitive urethane acrylate resin is applied to the three-dimensionally formed ink flow path member by a three-dimensional spray coating method to a uniform film thickness. Further, when laminating and joining the cured film surfaces of the first and second photosensitive resins coated with the ink-resistant photosensitive resin, an electron beam is irradiated from a substrate having a discharge port or a diaphragm side. By doing so, the photosensitive resin coated surfaces having ink resistance are joined and cured.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments.

FIG. 1 is a sectional view of an ink jet head according to one embodiment of the present invention.

As shown in FIG. 1, a dry film photoresist cavity (cavity member 2) provided with an ink discharge pressurizing chamber 4, an ink supply path 5, and an ink reservoir chamber 6 is provided. The nozzle plate 1 and the second substrate 3 are joined. Here, photosensitive urethane acrylate resins 8 and 9 are applied and hardened in a uniform thin film on the surface that comes into contact with the ink in order to improve the ink resistance. The nozzle plate 1 uses a Ni electroformed plate or a SUS pressed plate.
US press plate is used. An ink ejection drive element 10 is adhered to the back surface of the ink pressurizing chamber of the second substrate 3 with an epoxy-based adhesive or an imide-based adhesive.
At this time, a stacked PZT actuator is used as the driving element.

FIGS. 2A to 2F and FIGS. 3A to 3D.
4 and FIG. 4 show a manufacturing process of the ink jet head in the present embodiment.

The nozzle plate 1 having the ink discharge ports is cleaned, dried and heated (from 50 degrees Celsius to 80 degrees Celsius).
After that, as shown in FIG. 2A, the cavity constituting member 2 (dry film photoresist, film thickness 25
Platen temperature (70 degrees Celsius to 120 degrees Celsius)
), Pressure (1-3 kgf / square cm), and dry film feed speed (0.5-2.0 m / sec).

In FIG. 2B, the cavity constituting member 2 is further laminated on the cavity constituting member 2 laminated in FIG. 2A. This is because the ink pressurizing chamber finally has a predetermined volume. Therefore, in the step of FIG. 2A, a thick cavity member (75 to 100 microns thick) may be used.
However, it is generally difficult to pattern a photosensitive material having an aspect ratio of 1 or more with respect to the film thickness, so that a thick dry film cannot always be used easily.

Subsequently, as shown in FIG. 2C, a photomask A11 having a predetermined pattern is superimposed on the cavity constituting member 2 provided on the nozzle plate surface. Exposure is performed from
At this time, the photomask A11 sufficiently covers the areas of the ink pressurizing chamber 4 and the ink reservoir chamber 6 in FIG.
Does not transmit UV light. Therefore, the cavity constituent member 2 in the area covered with the photomask A11 is not exposed. When exposure is performed as described above, the UV-irradiated portion undergoes a polymerization reaction to be cured and becomes insoluble in a developer. On the other hand, the unexposed portions do not cure and remain soluble in the developer.

After the exposure step, the unpolymerized (uncured) portion of the cavity constituting member 2 is immersed or sprayed in a developer (water, a weak alkaline aqueous solution (concentration of several percent and an organic solvent other than chlorine type)) or sprayed. Dissolve and remove, Fig. 2 (d)
Is obtained. Here, in order to improve the rigidity and ink resistance of the dry film on which the desired pattern is formed,
Secondary exposure (1-30 J / square cm) or heating (10 degrees Celsius)
0 degree to 200 degree Celsius) or both of them are used together to increase the degree of polymerization of the dry film. Conventionally, in the case of a dry film in which the developing solution is a chlorine-based solvent, for example, 1.1.1 trichloroethane, a certain degree of ink resistance can be secured in the above-described steps. However, when higher reliability is required, or when an aqueous development (water or weakly alkaline aqueous solution) type dry film is used, it is necessary to further improve the ink resistance of the ink contact portion. Therefore, as shown in FIG. 2 (e), a photosensitive urethane acrylate resin A8 is applied to a uniform film thickness (1 to 5 microns) on the patterning surface of the dry film including the ink contact portion. As shown, the composition is cured by UV light 12 (irradiation amount: 0.1 to 1.0 J / square cm). Here, photosensitive urethane acrylate resin A
The uniform thickness coating method of No. 8 is based on a three-dimensional spray coating method, which will be described later in detail.

On the second substrate (diaphragm) side, a predetermined cavity shape is basically obtained by the same manufacturing process as that on the nozzle plate side.

As shown in FIG. 3A, the second substrate (diaphragm) 3 is cleaned, dried and heated (from 50 degrees Celsius to 50 degrees Celsius).
After the temperature is raised to 80 degrees Celsius, the cavity constituting member 2 (film thickness of 25 to 75 microns) is placed on the smooth surface of the second substrate 3 by a platen temperature (70 degrees Celsius to 120 degrees Celsius) and a pressure (1 to 3 kg).
f / square cm), dry film feed rate (0.5 to
(2.0 m / sec).

Subsequently, as shown in FIG. 3B, after a photomask B13 having a predetermined pattern is superimposed on the cavity constituting member 2 provided on the nozzle plate surface,
Exposure is performed from above the photomask B13. At this time, the photomask B13 sufficiently covers the areas of the ink pressurizing chamber 4 and the ink supply path 5 in FIG. 1 and does not transmit UV light. Therefore, the cavity constituent member 2 in the area covered by the photomask B13 is not exposed. When exposure is performed as described above, the UV-irradiated portion undergoes a polymerization reaction to be cured and becomes insoluble in a developer. On the other hand, the unexposed portions do not cure and remain soluble in the developer.

After the exposure step, the unpolymerized (uncured) portion of the cavity constituting member 2 is immersed in a developing solution (water, a weak alkali aqueous solution (a concentration of several percent and an organic solvent other than chlorine-based)) or sprayed. Dissolve and remove, Fig. 3 (c)
Is obtained. Here, in order to improve the rigidity and ink resistance of the dry film on which the desired pattern is formed,
Next exposure (1-30 J / square cm) or heating (100 degrees Celsius)
To 200 degrees Celsius) or a combination of both to increase the degree of polymerization of the dry film. Here, as shown in FIG. 3D, a photosensitive urethane acrylate resin B9 is applied to a uniform film thickness (1 to 5 microns) on the patterning surface of the dry film including the ink contact portion, similarly to the nozzle plate side. In addition, here, since the joining process shown in FIG.
V9 photosensitive urethane acrylate resin B9
Is not cured.

2 and 3, the ink pressurizing chamber 4, the ink reservoir chamber 6, the ink pressurizing chamber 4, and the ink supply path 5 formed on the nozzle plate and the second substrate, respectively, are positioned as shown in FIG. And pressurized (0.5-2.0
kgf / square cm), an electron beam (EB: EB:
Irradiation dose of 1 to 50 Mrad). This allows
The uncured photosensitive urethane acrylate resin B9 applied to the second substrate side is bonded and cured to the nozzle plate side.

Here, the ink resistance of the photosensitive urethane acrylate resin will be described.

Table 1 shows the change in film thickness due to ink immersion depending on the presence or absence of the photosensitive urethane acrylate resin coating.

[0022]

[Table 1]

Table 2 shows the change in bonding strength due to ink immersion depending on the presence or absence of the photosensitive urethane acrylate resin coating.

[0024]

[Table 2]

From the results of Tables 1 and 2, it can be clearly confirmed that the coating of the photosensitive urethane acrylate resin improves the ink resistance.

FIG. 5 shows a method for coating a photosensitive urethane acrylate resin with a uniform film thickness in this embodiment. This is called a three-dimensional spray coating method.
Then, a photosensitive urethane acrylate resin 16 is applied from a spray gun 17 which moves up and down in a direction perpendicular to the rotating surface to obtain a uniform film thickness. At this time, uniformity, film thickness and surface roughness are determined by the number of rotations of the work, the distance between the spray gun and the work, the elevating speed of the spray nozzle, the number of applications, and the viscosity of the photosensitive urethane acrylate resin.

Table 3 shows changes in the film thickness and surface roughness depending on the number of rotations of the work, the distance between the spray gun and the work, the elevating speed of the spray nozzle, the number of coatings, and the viscosity of the photosensitive urethane acrylate resin. It is.

[0028]

[Table 3]

From the results shown in Table 3, the number of rotations of the work, the distance between the spray gun and the work, the elevating speed of the spray nozzle, the number of coatings, and the viscosity of the photosensitive urethane acrylate resin were 40 to 80, 40 to 80, and 4 to 7 cm, respectively. 1 round trip ~
By making three round trips and 10 to 90 cps, a uniform film thickness of 2 to 3 microns can be obtained.

In the above embodiment, a dry film type, that is, a solid film is used as the photosensitive resin (photoresist) for forming the cavity. However, the present invention is not limited to this. Resins can also be used.

In this case, as a method of forming the photosensitive resin on the substrate, in the case of a liquid, a method using a squeegee used for printing or the like, that is, a wall having the same height as a desired photosensitive resin film thickness is formed around the periphery of the substrate. And remove excess resin with a squeegee. At this time, the viscosity of the photosensitive resin is 1000
５5000 cps is appropriate. Further, the height of the wall placed around the substrate needs to be determined in consideration of the volume shrinkage of the photosensitive resin due to exposure to light.

On the other hand, in the case of a solid, a photosensitive resin sheet is bonded onto a substrate by heating and pressing. In this embodiment, it is advantageous to use a solid film type, that is, a dry film type, from the viewpoint of easily and accurately controlling the thickness. Examples of such a dry film type include, for example, Confor Mask (registered trademark) 1000 and Confor Mask (registered trademark) manufactured by Dynachem.
2000, Laminar (registered trademark) DM and Dynamask (registered trademark) KM. In addition, examples of the photosensitive resin used in the present invention include many photosensitive resins used in the field of ordinary photolithography. Examples of the composition of these photosensitive resins include diazo resins, dimerized photopolymers using a sensitizer with a p-type photopolymer, a mixture of polyvinyl alcohol and a diazo resin, and unsaturated urethane oligomer-based photosensitive resins. Examples of the resin include a mixture of a resin, a bifunctional acrylic monomer, a photopolymerization initiator and a polymer, and a copolymer of N, N-dimethylmethacrylamide and, for example, acrylamidobenzophenone.

[0033]

As described above, the effects of the present invention can be variously enumerated as follows. 1. On a substrate having ink ejection ports, a cured film of a first photosensitive resin in which a pattern is formed in a single layer or a plurality of layers using photosensitivity, and a pattern is formed on a second substrate using photosensitivity. The cured film of the second photosensitive resin formed as a layer or a multilayer is formed such that the cured film surfaces of the cured film of the first photosensitive resin and the cured film of the second photosensitive resin face each other. In the ink jet head in which an ink passage is formed by laminating and joining, the ink contact portion and the joining portion of the cured films of the first and second photosensitive resins are the first and second portions.
Conventionally, by being coated with a uniform thin film made of a photosensitive resin having ink resistance different from that of the photosensitive resin, the joint between the substrate and the photosensitive resin, the joint between the photosensitive resins, or the photosensitive resin Although the ink itself was attacked by the contact of the ink and caused swelling and peeling, long-term reliability could be secured because the ink contact surface was coated with an ink-resistant photosensitive resin. In addition, since the photosensitive resin constituting the flow path and the resin having ink resistance are different,
For example, it is possible to select a photosensitive resin with good shape accuracy without considering ink resistance, or to select a photosensitive resin without considering ink resistance according to the type of ink used. The possibility of selecting the photosensitive resin forming the path is expanded, and the degree of freedom in design is improved. 2. The photosensitive resin with ink resistance is photosensitive urethane.
By using an acrylate resin, a photosensitive resin of an organic solvent development type containing a chlorine-based solvent such as 1.1.1-trichloroethane is conventionally used in order to enhance the ink resistance, and there is a possibility that the environment is adversely affected. However, in the present invention, long-term reliability for ink contact was ensured by coating a photosensitive urethane acrylate resin on an ink contact surface of a photosensitive resin which is a cavity constituent member. 3. When the photosensitive resin of the patterned photosensitive resin cured film is of an aqueous (including a weakly alkaline aqueous solution) developing type, it has an effect of not adversely affecting the environment. 4. By applying a photosensitive urethane acrylate resin to the three-dimensionally formed ink flow path member to a uniform thickness by a three-dimensional spray coating method, a uniform thick film (2 to 3 microns) can be formed even on uneven portions. ), Without damaging the desired cavity shape.
The ink resistance was able to be improved. 5. When laminating and joining cured film surfaces of the first and second photosensitive resins coated with a photosensitive resin having ink resistance,
By irradiating the resin-coated surfaces with ink resistance by irradiating an electron beam from the substrate or the vibration plate side with the discharge port, the number of manufacturing steps is relatively small and the productivity is good. And a highly reliable high-density multi-array inkjet head can be obtained by a simple method.

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of an inkjet head according to the present invention.

FIG. 2 is a cross-sectional view illustrating a manufacturing process of the inkjet head according to the present invention.

FIG. 3 is a cross-sectional view illustrating a manufacturing process of the inkjet head according to the present invention.

FIG. 4 is a cross-sectional view showing bonding between cavities formed on a nozzle plate and a second substrate in the present invention.

FIG. 5 is a schematic view of three-dimensional spray coating in a manufacturing process of an inkjet head according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nozzle plate 2 Cavity constituent member 3 Second substrate (vibrating plate) 4 Ink pressurizing chamber 5 Ink supply port 6 Ink reservoir chamber 7 Ink ejection port 8 Photosensitive urethane acrylate resin A 9 Photosensitive urethane acrylate resin B 10 Ink ejection Drive element (PZT) 11 Photomask A 12 Ultraviolet light (UV light) 13 Photomask B 14 Electron beam (EB) 15 Work 16 Photosensitive urethane acrylate resin 17 Spray gun

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41J 2/045 B41J 2/055 B41J 2/16

Claims (9)

(57) [Claims] 1. A cured film of a first photosensitive resin in which a pattern is formed in a single layer or a plurality of layers using photosensitivity on a substrate having an ink discharge port, and a photosensitivity is formed on a second substrate. A cured film of the second photosensitive resin having a pattern formed in a single layer or a plurality of layers by using the cured film surfaces of the cured film of the first photosensitive resin and the cured film of the second photosensitive resin. In the ink jet head in which an ink passage is formed by laminating and joining such that the inside is inward, the ink contact portion and the joining portion of the cured films of the first and second photosensitive resins are the first and second photosensitive materials. An ink jet head covered with a uniform thin film made of a photosensitive resin having an ink resistance different from that of a resin. 2. The ink jet head according to claim 1, wherein the photosensitive resin having ink resistance is a photosensitive urethane acrylate resin. 3. An energy used for discharging ink is generated at a position opposite to a surface of the second substrate on which a cured film of a photosensitive resin is formed and below an ink discharge port. The inkjet head according to claim 1, further comprising an energy generating element. 4. The ink jet head according to claim 3, wherein said energy generating element is a piezoelectric element. 5. The ink jet head according to claim 1, wherein the photosensitive resin of the patterned photosensitive resin cured film is of an aqueous (including a weakly alkaline aqueous solution) developing type. 6. The ink jet head according to claim 1, wherein the member forming the ink passage is an engineering plastic. 7. The ink-jet printer according to claim 1, wherein the photosensitive region of the photosensitive resin member and the ink-resistant photosensitive resin has a photosensitive region of two or more wavelengths from an electron beam to an infrared ray. head. 8. The ink jet head according to claim 2, wherein the photosensitive urethane acrylate resin is applied to the three-dimensionally formed ink flow path member in a uniform thickness by a three-dimensional spray coating method. Production method. 9. When laminating and joining the cured film surfaces of the first and second photosensitive resins coated with the ink-resistant photosensitive resin, electrons are emitted from a substrate having a discharge port or a diaphragm side. The method for manufacturing an ink jet head according to claim 1, wherein the photosensitive resin coated surfaces having ink resistance are joined and cured by irradiating a line.