JPH0435345B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inkjet head, and more particularly to an inkjet head for ejecting recording ink as droplets using a so-called inkjet recording method.

[Prior Art] An inkjet head applied to an inkjet recording method generally includes a fine ink ejection opening (orifice), an ink flow path, a chamber communicating with this flow path, and a chamber disposed for the flow path. It includes an energy generator that generates energy used for ejection.

Conventionally, such an inkjet head has been manufactured by forming fine grooves on a glass or metal plate by cutting or etching, and then joining the plate with these grooves to another suitable plate. Methods of forming ink channels are known.

[Problems to be Solved by the Invention] However, in heads manufactured by such conventional methods, the inner wall surface of the ink flow path to be cut is too rough, and the ink flow is affected due to the difference in etching rate. Distortion may occur in the passage, making it difficult to obtain a passage with constant passage resistance, and the ink ejection characteristics of the manufactured ink jet head tend to vary. or,
There are also problems in that the plate tends to chip or crack during cutting, resulting in poor manufacturing yield. When etching is performed, there is a disadvantage that there are many manufacturing steps, which increases manufacturing costs.

Furthermore, problems common to the above-mentioned conventional methods include the grooved plate with grooves for the ink flow path, and drive elements such as piezoelectric elements and heating elements that generate energy used to eject ink. (Also referred to as "energy generating body" or "energy generating element") When bonding with a substrate provided with
One problem is that it is difficult to align each other, and mass production is not possible.

Therefore, the development of an inkjet head having a structure that solves these problems is eagerly awaited.

The present invention has been made in view of the above problems, and
One of the objects is to provide an inexpensive, precise, and highly reliable inkjet head. Another object of the present invention is to provide an ink jet head in which the ink flow path is finely machined with high accuracy and high yield.

[Means for Solving the Problems] The ink jet head of the present invention that achieves the above object includes a plurality of ejection ports for ejecting ink, and a plurality of ejection ports provided corresponding to each ejection port. The inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet printer inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet printer inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet inkjet ejecting of , the discharge port, the flow path, and the chamber are each formed by joining a substrate and a lid member via a wall member, the energy generator is provided on the surface of the substrate, and the wall The member is made of a cured layer obtained by curing a photosensitive resin, and the discharge port is formed by cutting.

[Function] The most important feature of the ink jet head of the present invention is that the wall member of the ink passage is formed of a cured layer of photosensitive resin. The ink jet head of the present invention has an ink passage that is highly reliable in size and shape and can be produced at low cost and with high yield by utilizing the precision microfabrication properties of photosensitive resin. Furthermore, since the inner wall surface of the ink passage is smooth, ink flows smoothly. Furthermore, even if there are minute irregularities on the substrate due to, for example, electrical wiring, the plasticity of the photosensitive resin can be used to fully cope with the minute irregularities and create ink passages with highly accurate dimensions and shapes. can be obtained. Therefore, the ink jet head of the present invention has extremely good ink ejection characteristics from the ejection opening (stability, uniformity, straightness, energy efficiency, etc. in ejecting ink) and ink supply characteristics in the passage. It has excellent effects.

A further feature of the ink jet head of the present invention is that the ejection opening is formed using the photosensitive resin wall member mentioned above, and that the ejection opening is formed by cutting. . Forming the discharge port by cutting is important in order to optimize the distance between the energy generator and the discharge port, but in the present invention, the above-mentioned photosensitive resin with excellent machinability is Since the discharge port is formed using the wall member, the discharge port surface on which the discharge port is provided can be made extremely smooth. In addition, since the photosensitive resin wall member has high adhesion, the state of strong adhesion between the substrate and the wall member and between the lid member and the wall member can be maintained even if the wall member is cut. . Therefore, according to the present invention, the ink ejection characteristics from the above-mentioned ejection ports can be made even more excellent while maintaining the strength of the ink jet head.

[Example] Hereinafter, an example of the present invention will be described in detail using the drawings.

1 to 7 are schematic diagrams for explaining the structure of the ink jet head of the present invention and its manufacturing procedure.

First, as shown in FIG. 1, a desired number of energy generating elements 2 such as heating elements or piezoelectric elements (two in the figure) are placed on a suitable substrate 1 made of glass, ceramics, plastic, metal, etc. ) to be placed. Incidentally, when a heating element is used as the energy generating element 2, the element generates thermal energy and heats the ink in the vicinity, thereby ejecting the ink. Further, when a piezoelectric element is used, ink is ejected by mechanical vibration of this element. Note that signal input electrodes (not shown) are connected to these elements 2.

Next, after cleaning and drying the surface of the substrate 1 on which the energy generating element 2 is provided, a dry film photoresist 3 ( Film thickness is approx.
25μ~100μ) at a speed of 0.5~0.4f/min, 1~3Kg/
Laminate under pressure of cm ² (Figure 2a,
b). Incidentally, FIG. 2b is a sectional view taken along the line X-X' of FIG. 2a.

At this time, the dry film photoresist 3 is pressed and fixed to the substrate surface 1A, and will not peel off from the substrate surface 1A even if some external pressure is applied thereafter.

Subsequently, as shown in FIG. 3, a photomask 4 having a predetermined pattern 4P is superimposed on the dry film photoresist 3 provided on the substrate surface 1A, and then an exposure light source 5 is used from above the photomask 4. Perform exposure. Note that the pattern 4P corresponds to a region that will later constitute an ink supply chamber, a narrow flow path, and an ejection port, and does not transmit light. Therefore, the area of the dry film photoresist 3 covered by the pattern 4P is not exposed. Also, at this time, it is necessary to align the installation position of the energy generating element 2 and the pattern 4P using a well-known method. In other words, consideration is given to positioning the element 2 at least in the narrow ink flow path that will be formed later.

When exposed as described above, the photoresist 3 outside the area of the pattern 4P undergoes a polymerization reaction, hardens, and becomes solvent insoluble. On the other hand, the unexposed photoresist 3 is not cured and remains solvent-soluble.

After the exposure operation, the dry film photoresist 3 is immersed in a volatile organic solvent such as trichloroethane to dissolve and remove the unpolymerized (uncured) photoresist, resulting in a cured photoresist film 3.
A recess shown in FIG. 4a is formed in H according to pattern 4P. Thereafter, the cured photoresist film 3H left on the substrate 1 is further cured in order to improve its solvent resistance. The method is
It is preferable to carry out thermal polymerization (heating at 130° C. to 160° C. for about 10 minutes to 60 minutes), to perform ultraviolet irradiation, or to use both in combination.

Among the recesses thus formed in the cured photoresist film 3H, 6-1 corresponds to an ink supply chamber in the ink jet head, and 6-2 corresponds to an ink flow path. In addition, Fig. 4b shows
FIG. 4 is a sectional view taken along line Y-Y' in FIG. 4a;

On the upper surface side of the substrate 1, on which wall members of grooves for forming ink passages including an ink supply chamber 6-1, an ink narrow channel 6-2, etc. have been formed through the above-described steps,
As shown in FIG. 5, a flat plate (lid member) 7 constituting the ceiling is attached. The specific method for this is as follows: (1) After coating a flat plate of glass, ceramics, metal, plastic, etc. with an epoxy adhesive to a thickness of 3 to 4 μm using a spinner, preheating is performed to bring the adhesive to the so-called B stage. This is pasted on the cured photoresist film 3H and the adhesive is fully cured, or (2) a flat plate of thermoplastic resin such as acrylic resin, ABS resin, polyethylene, etc. is directly placed on the cured photoresist film 3H. There are methods such as heat fusion.

As shown in the figure, the flat plate 7 is provided with a through hole 8 for connecting an ink supply pipe (not shown).

After the substrate with the grooves formed thereon and the flat plate have been bonded together as described above, cutting is performed along line C-C' in FIG. This occurs in the ink narrow channel 6-2.
This is done to optimize the distance between the energy generating element 2 and the ink ejection port 9. The area to be cut is determined as appropriate. For this cutting, a dicing method commonly used in the semiconductor industry is used. FIG. 6 is a sectional view taken along the line Z--Z' in FIG. 5. Then, the cut surface is polished and smoothed, and the ink supply pipe 10 is attached to the through hole 8 to complete the ink jet head (FIG. 7).

In the above embodiments, a dry film type, that is, a solid one, was used as the photosensitive resin composition (photoresist) for creating grooves, but the present invention is not limited to this, and a liquid type photoresist was used. Of course, photosensitive resin compositions can also be used.

The method of forming a coating film of this photosensitive resin composition on the substrate is a method using a squeegee, which is used when producing a relief image, in the case of a liquid, that is, the same height as the desired film thickness of the photosensitive resin composition. In this method, a wall is placed around the substrate and excess resin composition is removed using a squeegee. In this case, the appropriate viscosity of the photosensitive composition is 100 cp to 300 cp.
Further, the height of the wall around the substrate needs to be determined in consideration of the evaporation of the solvent component of the photosensitive resin composition. On the other hand, in the case of a solid material, the photosensitive resin composition sheet is attached onto the substrate by heat-pressing.

Incidentally, in the present invention, it is advantageous to use a solid film type material in terms of handling and the fact that the thickness can be easily and accurately controlled. Examples of such solid materials include DuPont's permanent photopolymer coatings.
RISTON, solder mask 730S, 740S, same
There are photosensitive resins commercially available under trade names such as 730FR, 740FR, and SM1. In addition, as the photosensitive resin composition used in the present invention, there are many other photosensitive resin compositions that are used in the field of ordinary photolithography. Examples of these photosensitive resin compositions include diazoresin, P-diazoquinone, photopolymerizable photopolymers using a vinyl monomer and a polymerization initiator, and dimerized photopolymers using polyvinyl cinnamate and a sensitizer. Photopolymer, mixture of orthonaphthoquinone diazide and volac type phenolic resin,
Mixture of polyvinyl alcohol and diazo resin, 4
- Polyether-type photopolymers made by copolymerizing glycidyl ethylene oxide with benzophenone or glycidyl chalcone, copolymers of N,N-dimethylmethacrylamide with e.g. acrylamide benzophenone, unsaturated polyester photosensitive resins [e.g. APR ( Asahi Kasei), Tevista (Teijin), Sonne (Kansai Paint), etc.], unsaturated urethane oligomer-based photosensitive resins, photosensitive compositions in which a photopolymerization initiator and polymer are mixed with bifunctional acrylic monomers, dichromic acid-based photosensitive resins Resist, non-chromium water-soluble photoresist, polyvinyl cinnamate photoresist, cyclized rubber azide photoresist, and the like.

[Effects of the Invention] The effects of the present invention explained in detail above include:
Various types can be listed as follows.

(1) Since the main process of manufacturing the head is based on so-called printing technology, it is extremely easy to form the detailed parts of the head in a desired pattern. Furthermore, a large number of heads with the same configuration can be processed simultaneously.

(2) Productivity is good because the number of manufacturing steps is relatively small.

(3) It is possible to easily and reliably align the main components, and heads with high dimensional accuracy can be obtained at a high yield.

(4) An ink jet head with high-density multi-discharge ports can be obtained by a simple method.

(5) It is extremely easy to adjust the thickness of the groove walls constituting the ink flow path, and a flow path with desired dimensions (e.g. groove depth) can be formed depending on the thickness of the photosensitive resin composition layer. be able to.

(6) Continuous and mass production is possible.

(7) Since it is not necessary to use etching liquid (strong acids such as hydrofluoric acid), it is also superior in terms of satellite safety.

(8) There is almost no need to use adhesive, so
The adhesive will not flow and block the groove, or adhere to the energy generator and cause functional deterioration.

As explained above, the most important feature of the ink jet head of the present invention is that the wall member of the ink passage is formed of a cured layer of photosensitive resin. The ink jet head of the present invention has an ink passage that is highly reliable in size and shape and can be produced at low cost and with high yield by utilizing the precision microfabrication properties of photosensitive resin. Furthermore, since the inner wall surface of the ink passage is smooth, ink flows smoothly. Furthermore, even if there are minute irregularities on the substrate due to, for example, electrical wiring, the plasticity of the photosensitive resin can be used to fully cope with the minute irregularities and create ink passages with highly accurate dimensions and shapes. can be obtained. Therefore, the ink jet head of the present invention has extremely good ink ejection characteristics from the ejection opening (stability, uniformity, straightness, energy efficiency, etc. in ejecting ink) and ink supply characteristics in the passage. It has excellent effects.

A further feature of the ink jet head of the present invention is that the ejection opening is formed using the photosensitive resin wall member mentioned above, and that the ejection opening is formed by cutting. . Forming the discharge port by cutting is important in order to optimize the distance between the energy generator and the discharge port, but in the present invention, the above-mentioned photosensitive resin with excellent machinability is Since the discharge port is formed using the wall member, the discharge port surface on which the discharge port is provided can be made extremely smooth. In addition, since the photosensitive resin wall member has high adhesion, the state of strong adhesion between the substrate and the wall member and between the lid member and the wall member can be maintained even if the wall member is cut. . Therefore, according to the present invention, the ink ejection characteristics from the above-mentioned ejection ports can be made even more excellent while maintaining the strength of the ink jet head.

[Brief explanation of drawings]

1 to 7 are schematic diagrams for explaining the structure of the ink jet head of the present invention and its manufacturing procedure. 2b is a sectional view taken along line X-X' in FIG. 2a, and FIG. 4b is a sectional view taken along line Y-Y' in FIG. 4a. In the figure, 1 is the substrate, 2 is the energy generator,
3 is a dry film photoresist (photosensitive resin), 3H is a cured photoresist film, 4 is a photomask, 4P is a pattern, 5 is an exposure light source, 6-1
6-2 is an ink supply chamber, 6-2 is an ink flow path, 7 is a flat plate (lid member), 8 is a through hole, 9 is an ejection port, and 10 is an ink supply pipe.

Claims (1)

[Scope of Claims] 1. A plurality of ejection ports for ejecting ink, a flow path provided corresponding to each ejection port and communicating with the corresponding ejection port, a chamber communicating with each flow path, and a chamber for communicating with each flow path; an energy generator disposed for each of the ejection ports and generating energy used for ejecting ink from the ejection ports, and each of the ejection ports, the flow path, and the chamber is connected to a substrate and a lid member. The energy generator is provided on the surface of the substrate, the wall member is made of a hardened layer of photosensitive resin, and the discharge port is cut. An inkjet head characterized by being formed by. 2. The inkjet head according to claim 1, wherein the energy generator is a heating element. 3. The inkjet head according to claim 1, wherein the energy generator is a piezoelectric element. 4. The inkjet head according to claim 1, wherein the cured layer comprises a polymeric resin layer. 5. The inkjet head according to claim 1, wherein the cured layer is solvent insoluble.