JPS6116862A - Liquid injection recording head - Google Patents

Abstract

PURPOSE:To miniaturize the titled recording head and reduce production cost, and to improve reliability and conduct recording with high quality by electrically connecting a discharging element and an external wiring section by using a flat connecting member. CONSTITUTION:Structure in which lead electrodes 11 for a discharging element 13 formed onto a first substrate 7 and external wirings 14 shaped onto a second substrate 8 are connected through a film carrier 18 is formed. The film carrier 18 supports a fied number of lead wires 20 in mutually parallel at regular intervals by a film 21 as a support member shaped to a flat rectangular sheet form from a material having insulating properties and flexibility, and tip sections connected to the lead electrodes 11 and the external wirings 14 are coated with gold, tin, copper, solder, aluminum or the like in the lead wires 20. According to such constitution, a distance between an orifice plate 12 and recording paper is reduced, thus improving the quality of printing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a liquid jet recording head, and more specifically, the present invention relates to a liquid jet recording head, and more particularly, to a discharge element that is a droplet discharge means for discharging recording liquid as flying droplets, and an electrical connection to the discharge element. The present invention relates to a liquid jet recording head having an external wiring section provided for applying a signal, and in which the ejection element and the external wiring section are electrically connected.

[Prior art] The liquid jet recording method, the so-called inkjet recording method, generates very little noise during recording and is capable of high-speed recording, but does not require special processing such as fixing on plain paper. Recently, it has been attracting attention because it has advantages such as being able to record without having to use it.

Among them, for example, the liquid recording jetting method described in Japanese Patent Application Laid-Open No. 54-51875 and German Opening Publication ([1OLS) No. 2843084] applies thermal energy to a recording liquid to eject droplets. It has a different feature from other liquid jet recording methods in that it obtains a driving force.

That is, in the recording method disclosed in the above bulletin, the liquid subjected to the action of thermal energy undergoes a state change accompanied by a sudden increase in volume, and the acting force based on this state change causes the tip of the recording head to change. Recording liquid is ejected from the orifice to form flying droplets, and these droplets adhere to a recording member to perform recording.

In particular, the liquid jet recording method disclosed in DOL32843084 is a so-called drop-and-demand recording method.
Not only can it be applied extremely effectively to recording methods, but it can also be easily implemented into a recording head with a full 1ine type recording head with high-density multi-orifices, making it possible to obtain high-resolution, high-quality images at high speed. It has characteristics.

The liquid jet recording head (hereinafter referred to as the recording head) of the device to which this recording method is applied has an orifice provided for ejecting liquid, and a liquid that communicates with the orifice and transmits thermal energy to eject droplets. a liquid discharge part having a liquid flow path that includes a heat acting part as a part of the structure;
An electric/thermal converter is provided as a means for generating thermal energy. An example of the conventional structure of such a recording head is shown in the plan view of FIG.

In FIG. 1, the reference numeral 1 indicates a substrate of the recording head, and on this substrate 1, heating resistors 2, which are the above-mentioned electric/thermal converters, are provided in a number corresponding to the number of recording dots. Also, a large number of lead electrodes 3 are formed to guide drive signals from a drive circuit to each thermal resistor 2. Furthermore, a protective layer 4 is provided on the substrate 1, covering a portion of the heating resistor 2 and the lead electrode 3, as shown by the dotted line in the figure. This protective layer 4 protects the heating resistor 2 and the lead electrode 3 from the recording liquid ink, and an orifice plate (not shown) having an ejection opening for ink droplets is provided on this protective layer 4. Further, the reference numeral 5 indicates a flexible cable for guiding the drive signal from the drive circuit to the recording head, and although not shown in detail, wire bonding, soldering, They are connected by a method such as thermocompression bonding and fixed onto the substrate l.

However, in the structure of such a conventional recording head, the lead electrode 3 is extended to connect with the flexible cable 5 in the area indicated by the reference numeral 6 on the substrate 1. Due to the large number of cases, the following disadvantages were encountered. - (1) The area of the substrate l becomes larger.

(2) The required amount of a relatively expensive material such as Si for the substrate 1 increases, increasing the cost.

(3) Increasing the size of the substrate 1 makes etching, sputtering, and vapor deposition processes for forming the heating resistor 2, lead electrodes 3, etc. difficult, and hinders mass production.

(4) Since short-circuits, bridges, etc. occur in the lead electrode 3 on the originally unnecessary region 6 with the same probability as in other parts, the yield of the product deteriorates accordingly.

Furthermore, the above-mentioned recording heads generate heat depending on the equipment used, for example, 2.5 heads per layer for a calculator printer and 18 heads per layer for a facsimile printer. By changing the pattern of the resistor and lead electrode 1
As a result, the masks are different for each piece of equipment, making the etching, sputtering, vapor deposition, and other processes mentioned above complicated, leading to frequent work errors and lower product yields. .

In view of these drawbacks, a recording head having a structure as shown in FIG. 3, which is a perspective view of FIG. 2 and a sectional view taken along the X-Y line of FIG. 2, has been proposed. A discharge element having a liquid discharge portion and an external wiring portion for connecting it to the aforementioned drive circuit are separated on a first substrate 7 and a second substrate 8 having an opening into which this substrate 7 is fitted. It is provided.

That is, as shown in both figures, a plurality of heating resistors 10 similar to those described above are provided on the first substrate 7, and lead electrodes 11 and 11 connected to both ends of the heating resistors 10 are provided on the first substrate 7. An orifice plate 12 having a plurality of ejection ports 12a for ejecting ink droplets is provided corresponding to each heating resistor 10, and the above-mentioned ejection element 13 is constituted by the substrate 7 and these members.

Further, the second substrate 87 is provided with a number of external wirings 14 configuring the above-mentioned external wiring section corresponding to the above-mentioned lead electrodes 11.

In particular, as shown in detail in FIG. 3, each of the lead electrodes 11 and the external wiring 14 is connected by wire bonding via the wire 9, and the bonding portions at both ends of the wire 9 are connected to each other by wire bonding. It is sealed with a sealant 15 to increase reliability.

However, in the above structure, since the discharge element 13 and the external wiring section are connected by wire bonding, there are the following drawbacks.

(1) Since the sealant 15 bulges larger than the ejection surface of the orifice plate 12, it is not possible to improve the printing quality by reducing the distance between the ejection surface and the recording paper.

(2) If the above distance is made small, the sealant 15 will rub against the recording surface of the recording paper and the print quality will deteriorate.
5 will wear out and the reliability of the connection will drop.

(3) The sealant 15 may adhere to the orifice spray (12), and the stress may cause deformation of the orifice plate 12.

(4) The pitch between the connecting parts is currently 140 JL I
Since the discharge element 13 cannot be narrower than about I, the discharge element 13 is
It is difficult to deal with cases of multiple dots such as one-color dots (24×4 dots) or high-density dots.

(5) There are many constraints on the design, such as problems such as the area of the pounding butt, pattern arrangement around it, damage to the butt, and stress on the wire 9.

(6) Since it takes about 0.3 to 1 second to bond one cylinder, it takes a long time to connect the discharge elements in the case of a multi-dot discharge element, resulting in poor production efficiency and high costs.

(7) Product yield is poor.

The above-mentioned drawbacks are not limited to the above-mentioned liquid jet recording head, but apply to all of the types of liquid jet recording heads mentioned at the beginning.

[Objective] The present invention has been made in view of the above-mentioned conventional drawbacks, and it is an object of the present invention to provide a liquid jet recording head that can be miniaturized and reduce production costs, and is highly reliable and can perform high-quality recording. It is intended to.

[Summary of the Invention] In order to achieve the above object, the present invention uses a liquid ejecting recording head of the first type, that is, an ejecting element that is a droplet ejecting means for ejecting recording liquid as flying droplets. , and an external wiring section provided for applying an electric signal to the ejection element, and the ejection element and the external wiring section are electrically connected, the electrical connection We adopted a structure in which this was done using substantially flat tangential members.

[Embodiments] Hereinafter, details of embodiments of the present invention will be described with reference to FIG. 4 and subsequent drawings.

In each figure, parts that are the same as or correspond to those in FIGS. 2 and 3 are given the same reference numerals.

[First Embodiment] FIGS. 4(&), (b) to FIG. 6 explain the first embodiment of the present invention.

In this embodiment, as shown in FIG. 4(a), the first substrate 7
between the lead electrode 11 of the ejection element 13 made up of the various members provided thereon and the external wiring 14 provided on the second substrate B;

The fifth film is transferred through the film carrier 18 shown in FIG.
A connection structure as shown in the figure and FIG. 6 was adopted.

Note that 6th @ is a sectional view taken along the x-y line in FIG. 5.

The details of each part will be explained below.

The first substrate 7 is made of glass, ceramics, silicon, or the like.

As shown in FIG. 6, layered heat generating resistors 10 are provided on this substrate 7, the number of which corresponds to the number of dots of the recording head.

As the material constituting the layer of the heating resistor 10, almost any material can be used as long as it generates desired heat when energized.

Specific examples of such materials include tantalum nitride, nichrome, silver-palladium alloy, semi-silicon, hafnium, lanthanum, zirconium, titanium,
tantalum, tungsten.

Preferred examples include borides of metals such as molybdenum, niobium, chromium, and vanadium.

Among these materials constituting the heating resistor IO, metal borides are particularly excellent, and among them, hafnium boride has the best properties, followed by zirconium boride, Lanthanum boride, tantalum boride,
The order is vanadium boride and niobium boride.

The heating resistor lO is formed on the substrate 7-L by using the above-mentioned materials and using methods such as electron beam evaporation and sputtering.
is formed.

Further, layered lead electrodes 11 are formed on the substrate 7 and connected to both ends of each heating resistor 10. This lead electrode 11 is made of a material that can form a coarse and pinhole-free 5411 insulating layer on its surface, such as AJ, T
a, T i , M g , Hf.

Zr, V, W, Mo, Nb,
It is formed on the substrate 7 by a method such as vapor deposition using Si or an alloy thereof.

Further, each lead electrode 11 is formed so that its end opposite to the heating resistor 10 extends to the vicinity of both ends of the substrate 7, and on this end, a bonding layer is provided for connection to the film carrier 18 described above. A metal (bump) 19 is provided. This joining metal 19 is gold, copper, solder (Pb-Sn), Aj
! The lead electrodes 11 are formed on the outer ends of the lead electrodes 11 by plating, vapor deposition, or the like.

Furthermore, an orifice plate 12 having an elongated U-shape in cross section is provided above the outer end of each heating resistor 10 and each lead electrode 11. Ejection ports 12a for ejecting ink droplets are formed at each position facing the heating resistor 10.

This orifice plate 12 is made of nickel.

It is composed of a metal plate (metal plate formed by electroforming) formed by plating with precious metals such as copper, chromium, cobalt, or their phosphides, or a photosensitive film, or photosensitive glass, etc. For example, epoxy-based It is fixed onto the substrate 7 by adhesion using a silicon adhesive or the like.

Note that each heating resistor 10 and the lead electrode 11 are protected on the part covered by the orifice spray 12 on the substrate 7, which includes the portion excluding the outer end of each heating resistor 10 and each lead electrode it. A protective layer (not shown) is formed as necessary.

Materials for forming this protective layer include inorganic oxides such as 5i02, inorganic nitrides such as Si3N, titanium oxide, vanadium oxide, niobium oxide, molybdenum oxide, tantalum oxide, tungsten oxide, chromium oxide, zirconium oxide, and Transition metal oxides such as hafnium, lanthanum oxide, yttrium oxide, and manganese oxide; metal oxides such as aluminum oxide, calcium oxide, strontium oxide, barium oxide, and silicon oxide; and complexes thereof.

Silicon nitride, aluminum nitride, boron nitride.

High resistance nitrides such as tantalum nitride and their oxides.

Although nitride composites and semiconductors such as amorphous silicon and amorphous selenium have low resistance in bulk, their resistance can increase during manufacturing processes such as sputtering, CVD, vapor deposition, gas phase reaction, and liquid coating. Mention may be made of thin film materials.

Furthermore, a second protective layer is formed on the above-mentioned protective layer, if necessary. The forming material is AJ.

Ta, Ti, Zr, Hf, V, Nb, Mg, Si,
Metals such as Mo, W, Y, La, and oxides, carbides, nitrides, borides, etc. of alloys thereof are used.

The ejection element 13 is constituted by each of the above parts and the substrate 7.

On the other hand, the second substrate 8 is formed, for example, from a sintered body of ceramic, alumina, or the like.

A large number of external wirings 14 are formed on this substrate 8-H, facing each lead electrode 11 of the above-mentioned ejection element 13. This external wiring 14 is, for example, silver-palladium, silver-palladium,
Palladium-platinum.

Formed from conductor thick film printing materials such as gold-platinum, gold-palladium, gold, silver, and silver-platinum.

Further, as the substrate 8 and the external wiring 14 described above, a printed wiring board in which these are integrated can also be used. In this case, as the printed circuit board material, a paper phenol board, a glass epoxy board, a glass epoxy board, a glass polyimide board, a glass BT resin board, etc. are used, and as the wiring material, copper is mainly used.

Furthermore, each external wiring 14 on the side facing each lead electrode 11
A bonding metal 19 similar to that described above is formed using the same material and method as described above.

On the other hand, the film carrier 18 supports a predetermined number of lead wires 20 parallel to each other at predetermined intervals by a film 21, which is a supporting member formed into a flat rectangular thin plate shape from an insulating and flexible material. Each lead wire 20 is provided so as to pass through the film 21 and have both ends protrude from the side end surface of the film 21 by a predetermined distance. The lead wire 20 is made of copper, copper alloy, Fe-Ni alloy, etc., and is connected to at least the lead electrode IT and the external wiring 1.
The tip connected to 4 is gold and tin.

It is covered with a thin film formed by plating or vapor deposition of copper, solder, aluminum, etc.

The type of the above-mentioned joining metal 19 is -1- lead wire 2.
The selection is made according to the metal type and connection method of the connection part of 0.

In the configuration shown below, the discharge element 13 and the external wiring 14 are connected by placing the film carrier 18 between the first and second substrates 7.8 as shown in FIGS. 5 and 6, and One of the protruding ends of each lead wire 20 of the film carrier 18 is bonded to each lead electrode 11 on the first substrate 7 via a bonding metal 19, and the other end is bonded to each external wiring 14 on the second substrate 8. This is done by bonding through the bonding metal 19. Note that the above-mentioned bonding method includes methods such as thermocompression bonding, eutectic bonding, reflow, and ultrasonic waves.

As described above, according to this embodiment, since the ejection element 13 and the external wiring 14 are connected via the film carrier 18, the following advantages can be obtained.

(1) Since the connection part (film carrier 18) between the ejection element 13 and the external wiring 14 is flat and the amount of protrusion from the ejection surface of the orifice plate 12 is small, the distance between the orifice plate 12 and the recording paper can be reduced. can improve printing quality.

(2) Even if the above-mentioned distance is made small, the connecting portion does not hit the recording paper, so the reliability of the connection is improved.

(3) The pitch between the connecting portions can be made narrower than the conventional 140#L11 or so, and it is possible to cope with an increase in the number of dots and high density dots in the ejection element 13.

(4) Production efficiency is improved because connections can be made all at once in a short time. Note that the same effect as described above can be obtained by making the connection not only by the above-mentioned film carrier 1B but also by a lead wire supported by a flat support member.

[Second Embodiment] FIGS. 7 and 8 illustrate a second embodiment of the present invention, and FIG. 8 is a sectional view taken along the X-Y line of the perspective view of FIG. 7.

As shown in both figures, in the case of this embodiment, the ejection elements 13 on the first substrate 7-1 are constructed in the same manner as in the first embodiment, but a large number of lead frames 22 are arranged on the second substrate 8. is provided, and the discharge element 13 is connected to an external wiring section via this lead frame 22.

It is connected to an external wiring section (not shown) on the second substrate 8, or is formed integrally therewith, that is, as an extension of the external wiring section.

The lead frames 22 are scattered in correspondence with the lead electrodes 11 of the ejection element 13, and their tip portions protrude by a predetermined distance from the side edge of the second substrate 8 facing each lead electrode 11, and the bottom surface of the tip portion is Bonding metal 1 of lead electrode 11
It is configured so as to be in contact with a part of the surface of 9.

Furthermore, a coating of gold, copper, tin, solder, aluminum, or the like is formed on the surface of at least a portion of the leading edge of the lead frame 22 by plating, vapor deposition, or the like.

As shown in both figures, the connection between the discharge niremen) 13 and the external wiring section is made by thermocompression bonding, eutectic bonding, or reflow bonding between the leading edge of each lead frame 22 and the tip of each lead electrode 11 via a bonding metal 19. This is done by bonding using methods such as , ultrasonic waves, etc.

Note that depending on the type of metal at the joint portion of the lead frame 22 and the joining method, the type of joining metal may be gold.

The material is selected from copper, solder, aluminum, etc., and the forming method is also selected.

Further, the material of the substrate 8 may be any material as long as it can fix the lead frame 22, and a sintered body such as ceramic or alumina, resin, or the like is used.

According to the configuration of this embodiment as described above, the discharge element 1
Connection part between 3 and external wiring part (lead frame 22)
Since it is flat and connections can be made all at once, the same effects as in the first embodiment can be obtained.

Note that the same effects as in the first embodiment can be obtained by making the connection described in -1- not only with the lead frame 22 but also with a flat electrode.

[Third Embodiment] FIGS. 9 to 11 illustrate a third embodiment of the present invention.

In this embodiment, an anisotropic conductive film 23 shown in FIG. 9 is used, and as shown in FIG. 10 and FIG. The second external wiring 14 is connected.

Note that the discharge element 13 and the external wiring 14 are constructed almost the same as in the first embodiment described above, except that the lead electrode 11 of the discharge element 13 and the external wiring 14 are not provided with the aforementioned bonding metal 19.

As shown in FIG. 9, the above-mentioned anisotropic conductive film 23 includes an adhesive layer 25 on one surface of a film material 24 formed from synthetic rubber such as silicone rubber into a flat rectangular thin plate shape. For example, conductors 26 made of metal foil such as nickel or copper are alternately provided in stripes.

The particularly necessary conditions for this anisotropic conductive film 23 are as follows:
Ejection element 13 and external wiring 1 when driving the recording head
Since a current of about 400 A flows between the two layers, the current capacity should be sufficiently larger than this. As such an anisotropic conductive film, for example, JSRMF connector manufactured by Japan Synthetic Rubber Co., Ltd. is known, and its current capacity is IA.

The anisotropic conductive film 23 as described above is placed between the ends of the lead electrodes 11 on the substrate 7 and the substrate 8-L, as shown in FIGS. Each conductor 26 is bonded by bridging it onto the end device of the external wiring 14 and bonding it onto the substrate 7.8 by heating at a temperature of about 180 to 220° C. at the same time as applying pressure. Each lead electrode 11 and each external wiring 14 are connected via.

According to the configuration of the second embodiment, the above-mentioned $1. As in the second embodiment, the connecting portion (anisotropic conductive film 23) between the discharge elm plate 13 and the external wiring 14 is flat, and the connection can be made all at once, so that the same effect as described above can be obtained.

Further, the adhesive strength of the anisotropic conductive film 23 is 300
g/c ■ degree □ degree, 1 of conventional wire bonding
Since it is much larger than about 0 g/cm, the reliability of the connection is significantly improved.

Furthermore, since the anisotropic conductive film 23 has anisotropic conductivity in a direction perpendicular to a direction parallel to the stripes of each conductor 26, the alignment of the film before bonding is done in the stripe direction. If the axial directions of the lead electrode 11 and the external wiring 14 are made parallel, the direction of the stripes and the direction orthogonal to the same direction do not need to be made strictly, which is extremely simple.

Further, since the bonding metal 19 is not provided between the lead electrode 11 and the external wiring 14, the number of man-hours is reduced compared to the wIJ1 embodiment.

Note that the same effect as described above can be obtained by using not only the above-described anisotropic conductive film 23 but also a flat conductive member having anisotropic conductivity for the above-mentioned connection.

[Fourth example] FIG. 12 explains a fourth embodiment of the present invention.

In the case of this embodiment, the recording head is configured as a multi-head in which ejection members 13 similar to those of the first embodiment described above are arranged in a row on a plurality of first substrates 7-L.

Further, on the second substrate 8, there are external wirings 14 similar to those in the first embodiment corresponding to each lead electrode 11 of the total discharge Niremen) 13.
Each of them is provided.

The connection between the discharge elements 13 and the external wiring 14 is also made via the film carrier 18, which is almost the same as described above. In this case, the film carrier 18 is connected to all discharge elements 13.
A lead wire 20 is formed to be elongated and correspond to each lead electrode 11 of all the ejection elements 13, and is provided with a lead wire 20 corresponding to each lead electrode 11 of all the ejection elements 13. Using this film carrier 18, each lead electrode 11 of all the ejection elements 13 is and each external wiring 14 is connected.

In this way, the present invention can also be applied to the case of multi-heads,
The same effect as described above can be obtained. Particularly in this case, significant effects can be obtained in terms of reducing man-hours and improving production efficiency by making connections all at once.

Note that the connecting parts between the discharge element 13 and the external wiring 14 are not limited to those in each of the following embodiments, but may be any other as long as the connecting part is flat, and the same effect as described above can be obtained.

It goes without saying that the present invention is applicable not only to the recording heads of the above-described embodiments but also to all liquid jet recording heads of the first type.

[Effects] As is clear from the above description, according to the present invention, in the liquid jet recording head of the type mentioned at the beginning, there is provided an ejection element that ejects recording liquid as flying droplets, and an electrical connection to this ejection element. Since the external wiring section for applying signals is electrically connected using a substantially flat connecting member, high-quality recording is possible, excellent reliability, and the ability to increase the number of dots and high-density dots. Moreover, it is possible to provide an excellent liquid jet recording head that has low production cost and can be miniaturized.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a conventional liquid jet recording head, FIG. 2 is a perspective view of another conventional recording head, and FIG.
4(a), 4(b) to 6, which are cross-sectional views taken along the Y line, illustrate the first embodiment of the present invention. FIG. 4(a) is a perspective view of the recording head before connection, and FIG. Figure 4(b) is a perspective view of the film carrier, Figure 5 is a perspective view of the recording head after connection,
Figure 6 is a sectional view taken along the X-Y line in Figure 5, and Figure 7 is a cross-sectional view of the
A perspective view of the recording head according to the embodiment, FIG.
9 is a perspective view of the anisotropic conductive film according to the third embodiment, FIG. 10 is a perspective view of the recording head according to the same embodiment, and FIG. 11 is the x-Y of the 1θ diagram. 12 is a perspective view of a recording head according to a fourth embodiment. 7.8... Board 10... Heating resistor 11...
・Lead electrode 12... Orifice plate 13...
・Discharge element 14...External wiring 18...Film carrier 19...Joining metal 20...Lead wire 22...
・Lead frame 23...Anisotropic conductive film 26...Conductor

Claims (5)

[Claims] (1) It has an ejection element that is a droplet ejection means for ejecting recording liquid as flying droplets, and an external wiring section provided for applying an electric signal to the ejection element, and the ejection element and A liquid jet recording head electrically connected to the external wiring section, wherein the electrical connection is made using a substantially flat connecting member. (2) The liquid jet recording head according to claim 1, wherein the connecting member is comprised of a lead wire supported by a flat support member. (3) The liquid jet recording head according to claim 1, wherein the connecting member is a flat metal electrode. (4) The liquid jet recording head according to claim 1, wherein the connecting member is made of a flat anisotropic conductive material. (5) The liquid jet recording head according to claim 2, wherein the support member is flexible.