JP2014000733A - Liquid discharge head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease variation in impact positions of ink drops discharged from a discharge port by narrowing the interval between a liquid discharge head and a recording medium, in order to enable printing with high picture quality.SOLUTION: In the inner lead bonding between a recording element substrate for ink discharge and a TAB tape, an insulation member composed of the same material as an adhesion layer for improvement of the adhesion between an orifice plate and the recording element substrate is formed on the recording element substrate.

Description

  The present invention relates to a liquid discharge head applied to a liquid discharge apparatus that performs a recording operation by discharging a recording liquid such as ink.

  A conventional liquid ejecting apparatus is a recording apparatus that performs recording by ejecting and adhering ink to a recording medium, and has the following characteristics. That is, recording can be performed on various recording media that can be recorded at high speed, noise during recording hardly occurs, and running cost is low. For this reason, it is widely adopted as an apparatus that bears a recording mechanism such as a printer, a word processor, a facsimile machine, and a copying machine. An ink jet recording head mounted on such a liquid ejecting apparatus is one that ejects ink droplets by pressurizing ink with an electromechanical conversion element such as a piezo element as a method for ejecting ink. Also known is an ink that heats ink by an electrothermal conversion element having a heating resistor and ejects ink droplets by the action of film boiling.

  Among the ink ejection methods described above, those using electrothermal conversion elements include a method (edge shooter method) in which ink droplets are ejected in parallel to a liquid ejection substrate on which heating resistors are arranged. Furthermore, there is a method (side shooter method) in which ink droplets are ejected perpendicularly to a liquid ejection substrate on which heating resistors are arranged.

  FIG. 5A shows a configuration of a general side shooter type liquid discharge head. FIG.5 (b) shows the BB cross section of Fig.5 (a). As shown in FIG. 5, an ink supply port 104 is opened in the shape of an elongated hole in the center of the silicon substrate 101, and a plurality of heating resistors 108 are formed on both sides of the ink supply port 104 at substantially equal intervals on this substrate. Are lined up. The substrate 101 on which such a heating resistor 108 is formed is called a recording element substrate.

  Outside the recording element substrate 101, external wiring for supplying power to the heating resistor 108 is connected to external extraction electrode pads 102 provided at both ends on the recording element substrate. Then, an orifice plate 105 having a plurality of discharge ports 106 is formed on the recording element substrate 101. Here, when the orifice plate 105 is formed on the recording element substrate 101, the adhesion layer 109 is formed for the purpose of improving the adhesion between the recording element substrate and the orifice plate. After forming the adhesion layer 109, the orifice plate 105 is formed, and the liquid discharge substrate 100 as shown in FIG. 5A is completed.

  As a method for connecting the external wiring and the electrode pad 102 in the liquid discharge head having such a configuration, a method is known in which a bump 103 is formed on the electrode pad and the bump and the wiring of the electric wiring substrate 200 are joined. Such a method is called a TAB (Tape Automated Bonding) mounting method. As a method of forming the bump 103, there is a method of forming a bump by forming a metal ball and bonding it to the electrode pad 102, which is disclosed in Patent Document 1, and in Patent Document 2, a plating method is used for the electrode pad. A method of forming bumps using the method is described.

  The electrical wiring substrate 200 is generally electrically connected to the bumps 103 of the liquid discharge substrate 100 by bonding a copper foil 203 onto the polyimide tape 201 with an adhesive 202, patterning, and using the copper foil 203 as a lead. It is. This electrical wiring substrate 200 is called a TAB tape, and a lead extending from the window portion (generally called a device hole) of the TAB tape 200 to the liquid discharge substrate 100 is called an inner lead 204. By joining the inner lead 204 and the bump 103, connection with external wiring is performed.

  After the TAB mounting as described above, the sealants 400 and 401 are applied to the connection portion between the bump 103 and the inner lead 204 using a dispenser, and are cured by heat. Thereby, the electrical connection part is sealed and the reliability of the electrical connection part is improved. FIG. 5A is a perspective view of the upper sealant 400 for explaining the electrical connection portion.

  The liquid discharge substrate 100 is bonded to the support member 300 with an adhesive 107 so that the ink supply ports 104 and 302 communicate with each other. The support member 300 is provided with a step portion 301 so that the electric wiring substrate 200 can be connected substantially horizontally to the surface of the electrode pad 102 of the liquid discharge substrate 100, and the electric wiring substrate 200 is bonded and fixed by an adhesive 205. Yes.

  The ink used for recording is supplied from the ink supply port 104 of the recording element substrate 101 to the orifice plate 105 via the ink supply port 302 provided in the support member 300 and discharged from the discharge port 106.

JP 2003-025587 A JP 2004-296497 A

  In the liquid discharge head having the conventional configuration, the recording element substrate and the inner edge 204 of the TAB tape 200 and the corner 110 of the edge of the electric wiring surface of the recording element substrate 101 are not electrically short-circuited. It is necessary to make a difference in the height of the TAB tape. However, on the other hand, in order to improve the print quality as a recording head, it is desirable to narrow the interval between the ink discharge port 106 and the recording medium.

  In addition, the liquid discharge head described above needs to be improved in response to high image quality typified by photographic printing, which is required for recent liquid discharge apparatuses. In high image quality, it is possible to further reduce variations in landing positions of ink droplets ejected from the ejection port by narrowing the interval between the ejection port and the recording medium. However, in order to prevent edge short-circuiting, the relationship between the height h1 from the fixing surface of the liquid discharge substrate 100 to the top of the bump and the height h2 from the fixing surface of the liquid discharge substrate to the fixing surface of the TAB tape 200 is hl. <H2 (FIG. 5B) was required.

  As another method for narrowing the interval between the ejection port and the recording medium, there is a method of thinning the sealant layer h3 on the inner lead 204. However, when the sealant layer is thinned, the transmittance of ink, moisture, etc. As a result, the corrosion resistance of the electrical connection portion may be reduced.

  An object of the present invention is to reduce the variation in the landing positions of ink droplets ejected from ejection openings by narrowing the interval between the recording head and the recording medium in the liquid ejection apparatus, and enables a high quality printing. Is to provide.

The present invention for achieving the above object
A liquid discharge device comprising: an orifice plate having a discharge port for discharging a liquid; an energy generating element for generating energy for discharging the liquid; and an electrode pad portion electrically connected to the energy generating element. A substrate, an adhesion layer disposed between the orifice plate and the liquid discharge substrate, a bump protruding from the electrode pad portion,
In order to transmit an electrical signal supplied from the outside, a liquid discharge head including an electrical wiring board for electrical connection with the bump, formed in the vicinity of the bump with the same material as the adhesion layer An insulating member is provided.

  According to the present invention having the above-described configuration, the sealing material for the electrical connection portion can be formed without causing an electrical short circuit between the edge of the recording element substrate and the inner lead by providing the insulating member with the same material as the adhesive layer. The height can be lowered. Accordingly, the interval between the ejection port of the liquid ejection head and the recording medium can be narrowed, and the liquid ejection head capable of printing with high image quality with little variation in the landing positions of the ink droplets can be provided at low cost.

FIG. 1A is a perspective view of a liquid discharge head applied to the first embodiment. FIG. 1B is a cross-sectional view taken along line AA of the liquid discharge head shown in FIG. FIG. 1C is a plan view of the liquid discharge head shown in FIG. It is sectional drawing which shows the connection part of the connection example applied to 1st Embodiment. FIG. 3A is a perspective view of a liquid discharge head applied to the second embodiment. FIG. 3B is a plan view of the liquid discharge head shown in FIG. It is sectional drawing which shows the connection part of the connection example applied to 2nd Embodiment. FIG. 5A is a perspective view of a conventional liquid discharge head. FIG. 5B is a BB cross-sectional view of the liquid discharge head shown in FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
FIG. 1A is a perspective view of the liquid discharge head according to the first embodiment of the present invention, and is a view seen through the upper sealant 400 for explaining the electrical connection portion. 1B is a cross-sectional view of the liquid discharge head taken along line AA in FIG. 1A, and FIG. 1C is a plan view of the liquid discharge head shown in FIG. In these drawings, the same components as those in the conventional configuration in FIG. In addition, the recording element substrate of the liquid discharge head according to the present embodiment is formed with an energy generating element that generates energy used for discharging the liquid. In the present embodiment, an electrothermal transducer that generates thermal energy for causing film boiling to the ink in accordance with an electrical signal is used as the energy generating element.

  As shown in FIGS. 1A and 1B, the liquid discharge head has an ink supply port 104 opened in the shape of an elongated hole in the center of a silicon substrate, and a plurality of heating resistors are formed on the substrate. There is a recording element substrate 101 in which 108 are arranged on both sides of the ink supply port 104 at substantially equal intervals. Outside the recording element substrate 101, external wiring for supplying power to the heating resistor 108 is connected to external extraction electrode pads 102 provided at both ends on the recording element substrate. Then, an adhesion layer 109 is formed on the recording element substrate 101 and an insulating member 111 is formed. After forming the adhesion layer 109, the orifice plate 105 is formed on the adhesion layer, and the liquid discharge substrate 100 as shown in FIG. 1A is completed.

  The insulating member 111 is interposed between the inner lead 204 and the recording element substrate 101 and is provided at the edge of the recording element substrate 101. Further, when the adhesion layer 109 and the insulating member 111 are made of the same insulating material, they can be simultaneously formed by a photolithography technique. Here, the adhesion layer 109 and the insulating member 111 are made of an insulating material formed of a polyetheramide resin.

  Then, bumps 103 (for example, a thickness of 5 μm) protruding on the electrode pads 102 are formed, and are electrically joined by a TAB mounting method using the inner leads 204 of the electric wiring board (TAB tape) 200. Here, the bump 103 is formed by a plating method, whereby the bump height can be further lowered, and as a result, the sealing height h6 can be lowered. By this lead, an electric signal supplied from the outside is transmitted to the recording element substrate.

  In the TAB tape 200, a copper foil 203 is bonded to a polyimide tape 201 with an adhesive 202 and patterned, and the copper foil 203 is used as a lead. After the leads 204 and the bumps 103 are mounted by TAB, wiring is performed by performing gang bonding that performs electrical connection all at once. FIG. 2 is a diagram showing electrical connection using a gang bonding method. The inner lead 204 and the bump 103 are electrically connected by being heated and pressurized using a gang bonding tool 501. By this method, the leads 204 and the bumps 103 can be electrically connected satisfactorily.

  Then, sealing agents 400 and 401 are applied to the connection portion between the bump 103 and the inner lead 204 using a dispenser, and the electrical connection portion is sealed by curing it with heat.

  The liquid discharge substrate 100 is bonded to the support member 300 with an adhesive 107 so that the ink supply ports 104 and 302 communicate with each other. At this time, the support member 300 has a height relationship between a height h4 from the fixing surface of the liquid discharge substrate 100 to the top of the bump and a height h5 from the fixing surface of the liquid discharge substrate to the fixing surface of the TAB tape 200. A step portion 301 is provided so as to satisfy h4 ≦ h5 (FIG. 1B). Further, the TAB tape is bonded and fixed by an adhesive 205.

  In the liquid discharge head configured as described above, since the insulating member is provided in the vicinity of the electrode pad portion (in the vicinity of the bump), the edge of the recording element substrate and the inner lead are not short-circuited. Therefore, since the height of the fixed surface of the TAB tape can be lowered, the sealant layer h6 on the inner lead can be made thin.

  Furthermore, by providing an insulating member, a lead forming function can be added to the recording element substrate. Thus, an electrical short circuit due to the contact of the lead with the recording element substrate due to the deformation of the lead can be prevented without worrying about the deformation of the lead when bonding the lead. Further, since the adhesion layer and the insulating member are made of the same material and are simultaneously formed by photolithography, it is advantageous in terms of manufacturing cost and tact. In the liquid discharge apparatus equipped with the liquid discharge head of this embodiment, the interval between the discharge port and the recording medium can be narrowed, so that there is little variation in the landing position of the ink droplets, and high-quality printing is possible.

<Second Embodiment>
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 3A is a perspective view of the liquid discharge head according to the second embodiment of the present invention, and is a view seen through the upper sealant 400 for explanation of the electrical connection portion. FIG. 3B is a plan view of the liquid discharge head shown in FIG.

  In the second embodiment, the insulating member 111 is formed in a frame shape so as to surround the periphery of the bump 103.

  As an electrical connection method in this case, for example, a single point bonding method as shown in FIG. 4 is used. FIG. 4 shows a diagram in which the inner lead 204 as the connection terminal and the bump 103 are electrically connected by applying ultrasonic vibration and a load using a single point bonding tool 502. By this method, the leads 204 and the bumps 103 can be electrically connected satisfactorily. Further, when the insulating member 111 is formed in a frame shape so as to surround the periphery of the bump 103 in this embodiment, the bonding method described in the first embodiment, such as the gang bonding method, is used. It may be difficult to perform the electrical connection in a lump. This is because the lateral width of the gang bonding tool may interfere with both ends of the frame of the insulating member.

  In general, since the bump 103 is disposed at the edge of the recording element substrate 101, the shape of the insulating member 111 is often a rod. Therefore, the insulating member 111 is rigid in the pressing direction with respect to the recording element substrate surface, but is relatively small in the shearing direction. However, since the insulating member 111 is formed in a frame shape as shown in FIG. 3, the adhesion of the insulating member to the recording element substrate 101 is improved, so that the reliability with respect to the external force is improved.

  In the liquid discharge head according to the second embodiment configured as described above, the external force due to the cooling water of the dicing device sprayed when the recording element substrate is cut and separated from the silicon substrate, or the inner lead pressing when the TAB is mounted. It is sufficiently rigid against pressure. Furthermore, the yield and connection reliability at the time of manufacture can be improved as compared with the first embodiment.

DESCRIPTION OF SYMBOLS 100 Liquid discharge substrate 101 Recording element substrate 102 Electrode pad 103 Bump 104 Ink supply port 105 Orifice plate 106 Discharge port 107 Adhesive 108 Heating resistor 109 Adhesion layer 110 Edge (edge)
111 Insulating member 200 Electric wiring board (TAB tape)
201 Polyimide tape 202 Adhesive 203 Copper foil 204 Inner lead

Claims (6)

An orifice plate having a discharge port for discharging liquid;
A liquid discharge substrate comprising: an energy generation element that generates energy for discharging liquid; and an electrode pad portion electrically connected to the energy generation element;
An adhesion layer disposed between the orifice plate and the liquid ejection substrate;
Bumps projecting from the electrode pads,
In order to transmit an electrical signal supplied from the outside, an electrical wiring board for making electrical connection with the bump,
A liquid ejection head comprising:
A liquid discharge head comprising an insulating member formed of the same material as that of the adhesive layer in the vicinity of the bump.   The liquid ejection head according to claim 1, wherein the insulating member is disposed at an edge of the liquid ejection substrate.   The liquid ejection head according to claim 1, wherein the insulating member is formed in a frame shape surrounding an electrode pad portion of the liquid ejection substrate.   4. The liquid discharge head according to claim 1, wherein the insulating member is made of a polyetheramide resin. 5.   2. The electrical connection between the bumps and the electrode pad portion is performed by gang bonding in which the plurality of bumps and the plurality of electrode pad portions are connected together by heating and pressing. 5. The liquid discharge head according to any one of items 1 to 4. 2. The electrical connection between the bump and the electrode pad portion is performed by single point bonding for connecting each bump and each connection terminal using ultrasonic waves and a load. 5. The liquid discharge head according to any one of 4 above.

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