JPS58220755A - Ink jet recording head - Google Patents

Abstract

PURPOSE:To obtain a highly precise, highly reliable, low-cost ink jet recording head capable of giving high-quality (highly durable and high-density) pictures by providing an anchor at the joint between a photo-sensitive resin hardened film forming an ink pathway on a base plate and the base plate. CONSTITUTION:An ink discharge pressure generator element 2 is provided on a base plate 1 and covered with an electrically insulating film 3 and an ink- resistant film 4 as a protective film. Then, an anchor 5P is provided on these layers to improve the closeness between the protective layer and a photo-sensitive resin film to be laminated on the protective layer. In providing the anchor 5P, a chrome layer 5 is provided on the layer 4, a photo resisto 6 is coated on the chrome layer 5, and positioning is made by a photo mask 11. The photo resisto is exposed to light and developed to obtain a photo resisto picture 6P, unnecessary chrome is removed by etching, and the photo resisto picture 6P is removed to obtain a desired shape of anchor.

Description

[Detailed description of the invention] Ha. So-called. The present invention relates to an inkjet recording head for generating recording ink droplets used in an inkjet recording method.

An inkjet recording head applied to an inkjet recording method generally includes a fine ink ejection opening (orifice), an ink flow path, and an ink ejection pressure generating section provided in a part of the ink flow path.

Conventionally, such an inkjet recording head has been manufactured by, for example, forming fine grooves on a glass or metal plate by cutting or etching. A method is known in which an ink flow path is formed by joining a plate with grooves formed thereon to another suitable plate.

However, in the head made by such conventional method,
The roughness of the inner wall surface of the ink flow path to be cut is too thick, or distortion occurs in the ink flow path due to the difference in etching rate, making it difficult to obtain a flow path with constant flow resistance, resulting in poor inkjet recording after fabrication. Variations tend to occur in the ink ejection characteristics of the heads. Unfortunately, during cutting, the plate is prone to chipping and cracking.
There is also the drawback of poor manufacturing yield. Furthermore, when performing etching processing, there are many manufacturing steps. This has the disadvantage of increasing manufacturing costs. Furthermore, the common drawbacks of the above-mentioned conventional methods include the grooved plate in which the ink flow grooves are formed, the piezoelectric element that acts on the ink, and which generates mechanical stress.
One problem is that it is difficult to align the respective positions when bonding the lid plate on which drive elements such as heat generating elements are provided, resulting in a lack of mass production.

As an inkjet recording head having a structure that solves these drawbacks, a new inkjet recording head 1 equipped with an ink ejection pressure generating element is proposed, for example, in Japanese Patent Application Laid-Open No. 7-1-g 3.
It is proposed in No. g76.

The inkjet head manufactured using photosensitive resin solves the problems of conventional inkjet heads, such as finishing accuracy of the ink flow path, complexity of the manufacturing process, and poor manufacturing yield. In terms of quality, it is excellent. However, there remained a problem in the bonding force 1b between the substrate on which the ink ejection pressure generating elements are arranged and the channel wall of the photosensitive resin cured film formed thereon. In other words, the adhesion of the channel wall to the substrate is not sufficient, and the impact caused by cutting the outlet hole formation or the long time 1'・□
,: When ink droplets are ejected, the substrate at the ink ejection port part and the flow channel wall peel off, albeit very slightly, due to the impact of the ejection of the ink droplets and also due to changes over time, causing the ink droplets to separate. It was found that it affected the straightness of the bullet, or in other words, the accuracy of the point of impact. This has become a major hindrance in recent years as the inkjet recording system has been increasingly required to provide high resolution and high quality images using high density nozzles.

The present invention has been made in view of the above-mentioned drawbacks, and it is an object of the present invention to provide an inkjet head that is inexpensive, precise, reliable, durable, and capable of producing high-density, high-quality images. It is said that

The inkjet head of the present invention, which achieves the above object, is characterized by providing an anchor on the bonding surface between the protective layer formed on the substrate and the photosensitive resin cured film.

Embodiments of the present invention will be described in detail below using one drawing.

FIGS. 1 and 1 are schematic diagrams for explaining the structure of the inkjet recording head of the present invention and its manufacturing procedure.

,・ First, as shown in Figure 1 and Figure Ω, glass.

Ceramic, plastic or metal ring, suitable substrate l
A desired number of ink ejection pressure generating elements such as heating elements or piezoelectric elements are disposed on the top (1.2 in Figure 0). Incidentally, when a heating element is used as the ink ejection pressure generating element, this element generates ink ejection pressure by heating ink in the vicinity. Further, when a piezoelectric element is used, ink ejection pressure is generated by mechanical vibration of this element. Incidentally, a signal input electrode (not shown) is connected to each of these elements.

And, for the purpose of imparting electrical insulation, -5i02゜Ta
205. Al2O3, Gala, z, S i 3N4,
7. An example of an electrical insulating film 3 made of an inorganic oxide or inorganic nitride film such as BN, and an ink-resistant film that imparts ink properties to the surface 1. Noble metals such as Au, Pt, Pd, Ti,
A corrosion-resistant metal such as CrNi, Ta, Mo, W, or Nb or a corrosion-resistant alloy such as SUS or Monel metal is coated.The film 3 and the film are collectively referred to as a protective layer hereinafter.

In the present invention, anchors are provided on the protective layer in order to improve the adhesion between the protective layer and the photosensitive resin film laminated thereon. In the step shown in FIG. 3, a chromium layer S is provided on layer q to attach an anchor, and then in the step shown in FIG. 9, a photoresist B is applied on top of the chromium layer.

In the step shown in FIG. S, alignment is performed using a photomask 7 having a desired anchor shape, and the photoresist is exposed. Figure 4 shows that the exposed photoresist was developed to obtain a photoresist image P. In the process of Figure 7, unnecessary ROM was removed using an etching solution of perchloric acid and eucerium ammonium nitrate, and further. The photoresist image 7P is removed to obtain an anchor having the desired shape.

In this example, a process was adopted in which chroma was used to make the anchor, a film was formed by vapor deposition, and then etched. However, from the purpose of the present invention, there is no need to be limited to this, and it is not necessary to limit the process to processability, cost, etc. Various materials and methods can be adopted in consideration.

For example, as a material to be troweled to make up an anchor.

Gold, platinum, Pd, Ti, cr, Ni, Ta
, Mo, W, Nh.

Metals such as Co, glass, X, 5iO2-Ta205-Al
1(')3Si3N4. Examples include non-metals such as BN.

Also, sputtering and chemical plating are alternative coating methods to vapor deposition.

Electroplating etc. can be used. In addition, if the bonding force with the protective layer is insufficient with a single layer, it is also recommended to provide an intermediate layer (for example, Ti undercoated CO). The recommended thickness of the coating layer for forming the anchor is θ to /θμ.

In addition, although the anchor formation method using the photoetching method was introduced and explained, other methods include mask evaporation method,
Examples include lift-off method and photoforming method.

The substrate l having the anchor made of the chrome pattern SP manufactured in this way is cleaned and dried, and then in the process shown in FIG.
Dry film photoresist 7 (thickness, 25~00μ) heated to a moderate temperature is heated to 0/~ for 0S-957 minutes.
Laminate under pressure of 3 kg/7. Subsequently, as shown in FIG. 9, a photomask g having a predetermined pattern is superimposed on the dry film photoresist 7 provided on the substrate, and then exposure is performed from the top of this photomask. The pattern of the above photomask is as follows.

This corresponds to a region that will later constitute an ink supply chamber, an ink narrow channel, and an ejection port. When exposing, use a photomask
The chromium pattern 5p and the discharge pressure generating element λ on the substrate are aligned using a well-known method. When exposed in this manner, the photoresist 7 outside the pattern gP region undergoes a polymerization reaction, hardens, and becomes solvent insoluble. On the other hand, the photoresist 7 that has not been exposed to light is not cured and remains soluble in the solvent.

After the exposure operation, the dry film photoresist 7 is immersed in a volatile organic solvent such as trichloroethane (R) to dissolve and remove the unpolymerized (uncured) photoresist, leaving a pattern on the cured photoresist film 7. The recesses shown in FIG. 10 are formed according to gP. Thereafter, the cured photoresist film 7., 5P, and beads left on the substrate l are further hardened for the purpose of improving their solvent resistance. teeth.

It is preferable to carry out thermal polymerization (heating at 30'C to 0'C for about 70 minutes to 0 minutes), irradiate ultraviolet rays, or use both in combination. Of the recesses formed in the cured photoresist film 7P in this manner, the recesses 7--1 are located in the ink supply chamber of the completed inkjet recording head.
−． 2 corresponds to the ink narrow flow path.

After the diagonal upward step, the ink supply chamber 7-7. Ink narrow channel 7-. On the top surface of the substrate/on which the second groove wall is formed, the first/first groove wall is formed.
As shown in the figure, a cover 9 constituting the ceiling is attached.

As for this specific method.

1) After coating a flat plate of glass, ceramics, metal, plastic, etc. with an epoxy adhesive to a thickness of 3 to 1 μm using a spinner, the adhesive is preheated to a so-called B stage, and this is used as a hardened photoresist film 7P. The adhesive is then fully cured. Or.

2) Cured a flat plate of thermoplastic resin such as acrylic resin, ABS resin, polyethylene, etc. with a photoresist film 7P.
There is a method of directly heat-sealing.

As shown in FIG. 1, the cover 9 is provided with a through hole 10 for connecting an ink supply pipe (not shown).

As described above, after the substrate in which the grooves are formed and the flat plate are bonded, the substrate is cut along lines C and Ct in FIG. 12. This is the ink narrow channel 7-. 2, this is done to optimize the distance between the ink ejection pressure generating element and the ink ejection lower 2, and the area to be defined here is determined as appropriate. For this cutting, a dicing method commonly used in the semiconductor industry is used.

FIG. 13 is a sectional view taken along lines B and Bl in FIG. 7.2.

Then, the cut surface is polished to make it smooth, and an ink supply pipe is attached to the first through hole 10 to complete the inkjet recording head. (Fig. 111) Fig. 1S is a schematic diagram showing the cross-sectional shape of the anchor obtained in the above example, but the cross-sectional shape of the anchor that shows a better adhesion effect is shown in Fig. 1 O. can give. For example, in order to manufacture an anchor with such a cross-sectional shape.

Materials having different etching rates, that is, the lower layer material has a higher shearing rate than the upper layer material, are laminated on the protective layer, and a layer is prepared based on the kneading process.

Further, in this embodiment, the anchor was installed over the entire joint surface between the protective layer and the photosensitive resin cured film, but it may be limited to the vicinity of the ink discharge port where peeling is particularly likely to occur.

In addition, in the embodiment of the diagonal top, a dry film type, that is, a solid one, is used as the photosensitive composition (photoresist) for creating the groove, but the present invention is not limited to this. Of course, a liquid photosensitive composition can also be used. In the case of a liquid, the method for forming the photosensitive composition coating film on the substrate is a method using a squeegee, which is used when producing a relief image. In this method, a wall is placed around the substrate and excess composition is removed using a squeegee. In this case, the viscosity of the photosensitive composition is /θ0.9 to 300
cp is suitable: (・There is.Also, the height of the wall around the substrate r(
It is necessary to take this into account when making a decision.

On the other hand, in the case of a solid, the photosensitive composition sheet is attached to the substrate by heat-pressing. In the case where the present invention has not yet been made, it is more advantageous to use a solid film type material in terms of its handling and the fact that the thickness can be easily and accurately controlled. Examples of such solids include 1, for example, DuPont Co., Ltd., Manuman Photopolymer Coating) (15TO).
N, solder mask 7308, same 7rios, same'
There are photosensitive resins that are commercially available under trade names such as 7.7OF)L, 790P1(, 790P1(, 7.7OF), and SMI.Other photosensitive compositions used in the present invention include photosensitive resins, There are many types of photoresists used in the field of normal photolithography, such as photoresists. Examples of these photoresists include:

Diazoresins, P-diazoquinones, photopolymerizable photopolymers using vinyl monomers and polymerization initiators, binary type photopolymers using polyvinyl cinnamate, etc. and sensitizers, orthonaphthoquinonediazide, and 7
Mixture with volac type phenolic resin, mixture of polyvinyl alcohol and diazo resin, polyether type photopolymer copolymerized with googlycidyl ethylene oxide and benzophenone or grindyl chalcone, N,
A copolymer of N-dimethylmethacrylamide and, for example, acrylamidobenzophenone, an unsaturated polyester photosensitive resin (for example, APR (non-chemically formed)).

Tevista (Imajin), Sonne (Kansai Paint), etc.], unsaturated urethane oligomer photosensitive resin, photosensitive composition prepared by mixing a trifunctional acrylic monomer with a photopolymerization initiator and a polymer, 1 dichromic acid photoresist, Examples include non-chromium water-soluble photoresists, vinyl cinnamate photoresists, and cyclized film-based photoresists.

An advantage of the present invention described in detail above is that there is no peeling of the photosensitive resin cured film from the substrate around the ejection port due to impact caused by cutting the receptacle for forming the ejection port or due to long-term use.

Based on Example rC shown above, performance comparisons were made between an inkjet recording head provided with an anchor and an inkjet head not provided with an anchor, which differed only in A and T, and the results shown in the table below were obtained.

*/ Evaluation of 0 to 0 under each condition *λ Ink composition (ethylene 1) coal gO%, */
, 2% - Direct Black 3g 3%.

N-methyl-11 pyro IJ tons S%) *3 Droplet flight distance i3tnm

[Brief explanation of drawings]

FIGS. 1 and 1 are schematic diagrams illustrating the steps of manufacturing the inkjet recording head of the present invention. First, Figure 1 and Figure 1 are schematic cross-sectional views of the inkjet recording head of the present invention. l: Substrate 2 = Ink discharge pressure generating element 3: Electrical insulating film G: Ink-resistant film S Nichrome layer kP: Anchor A: Photoresist P: Photoresist image 7: Photoresist 7P: Hardened photoresist film 7-l : Ink supply chamber 7-. 2: Ink narrow channel ・1 g = Photomask gP: Pattern 10: Through hole //: Photomask /,! : Ink supply pipe/3: Ink discharge port 1 Fig. 269- Fig. 4 Fig. 6 Fig. 270- Fig. 9 Fig. 1 10 Fig. 11 1W. Figure 11 Figure 12 Figure 13 Figure 14

Claims (1)

[Claims] 1. An inkjet recording head comprising a substrate, a cured photosensitive resin film forming an ink passage on the surface of the substrate, and a cover for the passage. An inkjet recording head characterized in that an anchor is attached to a bonding surface between the substrate and the photosensitive resin cured film.