Liquid discharge head and manufacturing method thereof

A liquid discharge head includes, a substrate, a flow path wall member provided with a wall of a liquid flow path connected to a discharge port for discharging liquid, the flow path being formed by the flow path wall member and one surface of the substrate which are in contact with each other, and a coated resin member made of a cured material of a resin composition provided to cover end surfaces of the substrate, wherein a liquid repellent member having a contact angle of the resin composition larger than that of both the flow path wall member and the one surface is provided to cover at least a part of an intersection line between an outer lateral surface of the flow path wall member and the one surface.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a manufacturing method of a liquid discharge head for discharging liquid, and specifically relates to a manufacturing method of an ink jet recording head which performs recording by discharging ink on a recording medium.

2. Description of the Related Art

As an example of use of the liquid discharge head for discharging liquid, there is an ink jet recording head applied to an ink jet recording method for performing recording by discharging ink on a recording medium.

U.S. Pat. No. 6,471,901 discusses an ink jet recording head as described below. A substrate on which energy generating elements for generating energy used to discharge liquid such as ink are provided and a discharge element substrate which is provided on the substrate and includes liquid discharge ports and a flow path wall member in which a flow path is provided. The substrate with energy generating elements and the discharge element substrate are electrically connected to a flexible wiring substrate. The side surfaces of the substrate are coated with an end surface sealing member for protecting the side surfaces from ink, dust, and the like.

However, when a difference of a linear expansion coefficient between two members is very large such as in a case of a silicon substrate and a flow path wall member made of a resin, a joint strength between the substrate and the flow path wall member may be not sufficient, and there is a risk that peeling occurs. When the peeling occurs, there may be problems as described below. For example, when providing an end surface sealing member for covering the entire side surfaces of the substrate to reliably protect side surfaces of the substrate, the sealing material may reach the top surface of the substrate depending on viscosity and fluidity of the sealing material for forming the sealing member. In this case, the sealing material may reach the side surface of the flow path wall member, and intrude into a gap between the flow path wall member and the substrate depending on the physical property of the sealing material. Due to the intrusion of the sealing material, the joint strength of the joint section between the substrate and the flow path wall member decreases, so that there is a risk of peeling. In addition, there may be a risk that liquid such as ink intrudes into the same gap. In particular, when an ink jet recording head is elongated, or the flow path wall member is thickened, the above risks increase because the stress of the flow path wall member increases.

SUMMARY OF THE INVENTION

The present invention is directed to a liquid discharge head with high reliability which prevents the sealing material from intruding into a gap between the flow path wall member and the substrate. Also, the present invention is directed to a manufacturing method for easily manufacturing such a liquid discharge head.

According to an aspect of the present invention, the liquid discharge head includes: a substrate; a flow path wall member including a wall of a liquid flow path connected to a discharge port for discharging liquid, the flow path being formed by the flow path wall member and one surface of the substrate which are in contact with each other; and a coated resin member made of a cured material of a resin composition provided to cover end surfaces of the substrate, wherein a liquid repellent member having a contact angle of the resin composition larger than that of both the flow path wall member and the one surface is provided to cover at least a part of an intersection line between an outer lateral surface of the flow path wall member and the one surface.

According to the present invention, the sealing material is prevented from intruding into a gap between the flow path wall member and the substrate, so that it is possible to provide a liquid discharge head with high reliability. Also, it is possible to easily manufacture such a liquid discharge head without placing additional burden on the manufacturing process.

DESCRIPTION OF THE EMBODIMENTS

FIGS. 6A and 6Bare schematic perspective views of a liquid discharge head according to an exemplary embodiment of the present invention, andFIGS. 1A,1B, and1C are a top view A and a cross-sectional view B of the liquid discharge head.FIG. 1Bis a cross-sectional view taken along A-A′ line inFIG. 1A.FIG. 1Cis an enlarged view of a part ofFIG. 1B.

As illustrated inFIGS. 1 and 6, the liquid discharge head of the present invention includes a substrate2on which two lines of energy generating elements1for generating energy for discharging liquid such as ink are formed at a predetermined pitch and connection electrodes13for electrically connecting to the outside are formed. In the substrate2, a supply opening7is formed between the two lines of energy generating elements1. Over a surface102which is one of the two surfaces of the substrate2, discharge ports6opened above each energy generating element1, and individual flow paths8connected from the supply opening7to each discharge port6are formed by a flow path wall member3. On the surface of the substrate2, an adhesive layer (not illustrated in the figures) for improving adhesion between the substrate2and the flow path wall member3may be provided. The flow path wall member3is formed by a cured material of a resin composition including an epoxy resin or the like, but it is not limited to this material, and a metal or the like can be used.

The substrate2is electrically connected to an electric wiring member100via lead wires12of the liquid discharge head. Around the end surfaces101of the substrate2, a sealing member14is provided by a dispensing method or the like, and further, a sealing member15made of a cured material of a resin composition is provided.

As illustrated inFIGS. 1A,1B,1C and6A, the liquid discharge head according to the exemplary embodiment of the present invention includes a liquid repellent member20covering at least a part of an intersection line103located along a connection portion between the surface102which is one of the two surfaces of the substrate2and a outer lateral surface104of the flow path wall member3provided on the surface102. A contact angle of the resin composition for forming the sealing member15on the liquid repellent member20is larger than a contact angle of the resin composition for forming the sealing member15on the flow path wall member3and the surface102. A water contact angle of the liquid repellent member20is larger than the water contact angle of the flow path wall member3and the surface102. Since the liquid repellent member20is provided along the intersection line, liquid such as ink, and the sealing member14described below are difficult to come close to the intersection line.

A pure water static advancing contact angle of the liquid repellent member20can be 80 degrees or more, and more preferably, can be 90 degrees or more. More preferably, it can be 100 degrees or more. The surface102is coated with an inorganic or organic insulating film, or a metal protective film. The contact angle for the metal protective film and the inorganic film is 50 degrees or less, and the contact angle for the organic insulating film such as a thermoplastic resin is 70 degrees or less. The contact angle of the flow path wall member is 50 degrees or less when it is a metal, and is 70 degrees or less when it is a cured resin material.

The liquid repellent member20is formed by a material such as fluorine, a chemical compound containing silicon, and a resin.

The liquid repellent member20may be layered as illustrated inFIG. 1B, and provided in contact with the outer lateral surface104of the flow path wall member and the surface102at an angle, or as illustrated inFIG. 1C, the outer surface may have a rounded shape. The liquid repellent member20may also be provided along the entire intersection line around the flow path wall member3.

In the above description, the discharge ports6are provided in the flow path wall member3. However, the flow path wall member and a discharge port member which forms the discharge ports6may be provided separately. This will be illustrated using an example in the description of the manufacturing method.

In the liquid discharge head illustrated inFIG. 6B, a surrounding member105is provided around the flow path wall member3, and the liquid repellent member20is provided covering at least a part of an intersection line107between the outer lateral surface106of the surrounding member of the flow path wall member3and the surface102. When the flow path wall member is formed by a resin cured material, the surrounding member105is preferably formed by the same cured material. For example, by providing the surrounding member105having the same height as that of the flow path wall member, it is possible to produce effects such as improved wiping characteristics and improved protection of an element surface of the substrate. Similar to the liquid discharge head inFIG. 6A, the liquid repellent member20has a water contact angle larger than that of both the surrounding member and the surface102. Since the liquid repellent member20is provided along the intersection line107, liquid such as ink, and the sealing member14described below do not easily come in contact with the side surfaces of the substrate.

An example of the manufacturing method of the liquid discharge head according to the first exemplary embodiment of the present invention will be described below.FIGS. 2A,2B,2C,2D,2E,2F, and2G are schematic cross-sectional views illustrating an example of the manufacturing method of the liquid discharge head of the present invention, and these cross-sectional views are similar to that ofFIG. 1B.

As illustrated inFIG. 2A, a dissolvable resin layer4which is a mold of the flow path is formed on the substrate2including the energy generating elements1(not illustrated inFIG. 2A). The dissolvable resin layer4is formed by a pattern having a shape of the flow path8. For example, after lamination of a dry film or coating with a resist by spin coating on the dissolvable resin layer4, a patterning is performed on the dissolvable resin layer4, for example, by exposure with ultraviolet rays (deep-UV light) and development. As an specific example, polymethyl isopropenyl ketone (ODUR-1010 manufactured by TOKYO OHKA KOGYO CO., LTD.) is coated on the dissolvable resin layer4by spin coating and dried, and then the dissolvable resin layer4is exposed to the deep-UV light and a patterning is performed on the dissolvable resin layer4by development.

Next, as illustrated inFIG. 2B, after coating with the flow path wall member3on the dissolvable resin layer4, the flow path wall member in which the discharge ports6are formed is formed by performing ultraviolet-ray exposure (deep-UV light exposure) and developing the flow path wall member3.

Next, as illustrated inFIG. 2C, a liquid repellent material layer108is provided such that the liquid repellent material layer108covers the flow path wall member3, comes in contact with the outer lateral surfaces104and the surface102, and covers the intersection line103. The liquid repellent material is a photosensitive liquid repellent material which is applied by spin coating, laminating, or the like, and on which a patterning can be performed by, for example, exposure with ultraviolet rays (deep-UV light) and development. For example, the liquid repellent material is a film formed by a resin including an epoxy group containing a fluorine atom and a photopolymerization initiator.

After providing the liquid repellent material, by using a photo mask21as illustrated inFIG. 2Dand performing ultraviolet-ray exposure (deep-UV light exposure) and development, the liquid repellent member20can be formed only in a necessary area illustrated inFIG. 2E.

Next, as illustrated inFIG. 2F, the liquid supply opening7is formed by chemically etching the substrate2. For example, when using a Si substrate as the substrate2, the supply opening7is formed by anisotropic etching using a strong alkaline solution such as KOH, NaOH, and TMAH.

Next, by dissolving the dissolvable resin layer4, the resin in the flow path8is removed. The dissolvable resin layer4can be removed by dissolving and drying the dissolvable resin layer4after performing entire exposure using the deep-UV light. If ultrasonic processing is performed during the dissolution, the dissolvable resin layer4can be removed more quickly and completely.

Although not illustrated inFIG. 2, the substrates2on which an ink jet mechanism is provided are manufactured in a wafer form in which many chips are continuously arranged. Therefore, after manufacturing the wafer, the substrates2are cut and separated into chips by a dicing saw or the like.

As illustrated inFIG. 2F, after making electric connection for driving the energy generating elements1, a member such as an ink tank for supplying ink is attached. A resin composition is formed such that the resin composition fills the circumference of the substrate. The resin composition is cured to form the sealing member14and the sealing member15for protecting the leads, and the liquid discharge head is completed.

As the sealing member, an amine curing type epoxy resin composition or the like can be used, and as a base resin thereof, an epoxy resin having a butadiene skeleton, an alicyclic epoxy resin, and a bisphenol A-type epoxy resin can be used. The resin composition includes a filler, a curing auxiliary catalyst, and a solvent in addition to the base resin and a curing agent. As a sealing method with the composition, the composition is applied by the dispensing method or the like, and cured by heat or light to perform the sealing. The contact angle of the composition for the sealing member on the liquid repellent member is larger than the contact angles of the composition for the sealing member on both the flow path wall member3and the surface102, and thus even when the composition of the sealing member overflows on the surface102, it is possible to prevent the composition for the sealing member from coming close to the intersection line103.

In the present exemplary embodiment, the thickness of the flow path wall member3on the substrate is about 75 μm, and the distance from the side surface of the substrate to the side surface of the flow path wall member is about 10 to 50 μm.

An example of the manufacturing method of the liquid discharge head according to a second exemplary embodiment of the present invention will be described below.FIGS. 3A,3B, and3C are schematic cross-sectional views illustrating an example of the manufacturing method of the liquid discharge head of the present invention, and these cross-sectional views are similar to that ofFIG. 1B.

As illustrated inFIG. 3A, a material of the member which forms the flow path wall portion is applied on the substrate2which includes the energy generating elements1, by spin coating. This material is a photosensitive resist, and a patterning is performed on the material by ultraviolet-ray exposure (deep-UV light exposure) and development to form the flow path wall member3.

Next, as illustrated inFIG. 3B, an orifice plate layer10(an orifice plate portion) which is a discharge port member provided with the discharge ports is formed of a laminated dry film.

The orifice plate layer10of the dry film is a resist of the same photosensitivity as the flow path wall member3, and generally the orifice plate layer10and the flow path wall member3are formed by the same material from the view point of connection characteristics of the upper part of the flow path wall member.

Since the orifice plate layer10of the dry film is laminated in an appropriate condition, the orifice plate layer10is formed as if a lid were placed on the flow path wall member3without filling in the ink path between the flow path walls formed by the flow path wall member3.

Next, as illustrated inFIG. 3C, by performing ultraviolet-ray exposure (deep-UV light exposure) on the orifice plate layer10of the dry film and developing the orifice plate layer10, the discharge ports6are formed.

The subsequent processes are performed in the same way as in the first exemplary embodiment. The liquid repellent member is provided along the intersection line103between the surface102and the outer lateral surface104inFIG. 3C.

An example of the manufacturing method of the liquid discharge head according to a third exemplary embodiment of the present invention will be described below.FIGS. 4A,4B,4C,4D,4E, and4F are schematic cross-sectional views illustrating an example of the manufacturing method of the liquid discharge head of the present invention, and these cross-sectional views are similar to that ofFIG. 1B.

As illustrated inFIG. 4A, the flow path wall member3which forms only the flow path walls is applied on the substrate2which includes the energy generating elements1, by spin coating.

The material for the flow path wall member3is a photosensitive resist, and a patterning is performed on the material by ultraviolet-ray exposure (deep-UV light exposure) and development to form the flow path wall member3.

Next, as illustrated inFIG. 4B, a material5for implanting is accumulated to cover the substrate2and the flow path wall member3. An acrylic material for the implanting material can be used to prevent the flow path wall from falling during chemical mechanical polishing (CMP) in the next process.

Next, the top surface of the implanting material5is polished and cleaned by the chemical mechanical polishing (CMP) until the top surface of the flow path wall is exposed, and the form subjected to flattening processing as illustrated inFIG. 4Cappears.

Next, as illustrated inFIG. 4D, an orifice plate layer9which becomes an orifice plate portion of the discharge ports is applied by spin coating.

The orifice plate layer10is a resist of the same photosensitivity as the flow path wall member3, and generally the orifice plate layer10and the flow path wall member3are formed with the same material from the viewpoint of connection characteristics of the upper part of the flow path wall member. The orifice plate layer10may be formed by a laminated dry film.

Next, as illustrated inFIG. 4E, by performing ultraviolet-ray exposure (deep-UV light exposure) on the orifice plate layer10of a dry film and developing the orifice plate layer10, the discharge ports6are formed. Further, the unnecessary implanting material5is removed to form the surface102, the outer lateral surface104, and the intersection line103, so that the form illustrated inFIG. 4Fappears.

The subsequent processes are performed in the same way as in the first exemplary embodiment.

FIGS. 5A,5B,5C are diagrams illustrating the manufacturing method of a fourth exemplary embodiment, and these diagrams are cross-sectional views similar to that ofFIG. 2.

As illustrated inFIG. 5A, after providing electric connection for driving the energy generating elements1, a member such as a liquid accommodating member for supplying liquid is attached, and the liquid repellent material is applied by a needle23. At this time, the liquid repellent material which can be used is, for example, a composition including a condensation of a silane compound containing a fluorine-containing group and a silane compound containing a cationic polymerization group, and a photoacid generating agent. Of course, the liquid repellent material is not limited to the above.

Then, as illustrated inFIG. 5B, the material is irradiated with ultra-violet rays (deep-UV light)22, and the liquid repellent material is cured to form the liquid repellent member.

Then, as illustrated inFIG. 5C, the sealing member14which fills the circumference of the substrate and the sealing member15which protects the leads are formed, and the liquid discharge head is completed.

In the present exemplary embodiment, the liquid repellent processing is not performed in a photolithography process, but performed in a mounting process, so that there is an advantage that the liquid repellent processing can be easily performed without using large-scale production equipment.

The liquid discharge head can be applied to various industrial fields such as discharging a wiring forming material and an electronic component forming material, in addition to the ink jet recording method.

This application claims priority from Japanese Patent Application No. 2009-143524 filed Jun. 16, 2009, which is hereby incorporated by reference herein in its entirety.