JPH0825271B2 - Liquid jet recording head - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid jet recording head, and more particularly, to a discharge ejector which is a droplet discharge means for discharging a recording liquid as flying droplets, and an electric discharge element. The present invention relates to a liquid jet recording head, which has an external wiring portion provided for applying a signal, and in which the ejection element and the external wiring portion are electrically connected.

[Prior Art and Background Art] The liquid jet recording method, so-called ink jet recording method, has a negligible noise generation at the time of recording, high-speed recording is possible, and special recording such as fixing on plain paper is performed. Since it has advantages such as being able to record without requiring processing, it has recently been attracting attention.

Among them, for example, a liquid jet recording method described in Japanese Patent Laid-Open No. 54-51875 and German Patent Publication (DOLS) 2843064 discloses that a recording liquid is ejected by applying thermal energy to the recording liquid. It has different characteristics from other liquid jet recording methods in terms of obtaining driving force.

That is, in the recording method disclosed in the above publication, the liquid subjected to the action of thermal energy causes a state change accompanied by a sudden increase in volume, and the action force based on this state change causes an orifice at the tip of the recording head portion. The recording liquid is ejected to form flying droplets, and the droplets adhere to the recording member to perform recording.

In particular, the liquid jet recording method disclosed in the DOLS2843064 publication is not only very effectively applied to the so-called drop-on-demand recording method, but also the recording head part is a full line type high density multi-orifice recording. The feature is that the head can be easily embodied and a high-resolution, high-quality image can be obtained at high speed.

A liquid jet recording head (hereinafter abbreviated as a recording head) of an apparatus to which this recording method is applied has an orifice provided for ejecting a liquid and a thermal energy for ejecting a liquid droplet that is in communication with the orifice. The liquid ejecting section has a liquid flow path having a heat acting section that is a part that acts as a part of the configuration, and an electric / heat converting body 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, reference numeral 1 is a substrate of a recording head, and on the substrate 1, a number of heating resistors 2 which are the above-mentioned electric / thermal converters are provided corresponding to the number of recording dots. Further, a large number of lead electrodes 3 for guiding the drive signal from the drive circuit to the heating resistor 2 are formed. Further, a protective layer 4 is provided on the substrate 1 so as to cover a part of the heating resistor 2 and the lead electrode 3 as shown by a dotted line in the figure. The 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 ink droplet ejection port is provided on the protective layer 4. Reference numeral 5 denotes a flexible cable for guiding the drive signal from the drive circuit to the recording head. Although not shown in detail, wire bonding, soldering, heat They are connected by a method such as pressure bonding and fixed on the substrate 1.

However, in such a conventional recording head structure,
The lead electrode 3 is extended in order to connect to the flexible cable 5 in the area indicated by reference numeral 6 on the substrate 1, and there are many lead-out portions of the lead electrode 3, which causes the following drawbacks.

(1) The area of the substrate 1 is increased.

(2) The required amount of the relatively expensive material for the substrate 1 such as Si is large and the cost is high.

(3) Increasing the size of the substrate 1 makes it difficult to perform steps such as etching, sputtering, and vapor deposition for forming the heating resistor 2 and the lead electrode 3 and hinders mass production.

(4) Since a short circuit, a bridge or the like occurs at the lead electrode 3 portion on the originally unnecessary area 6 with the same probability as at other portions, the product yield is deteriorated accordingly.

In addition, the recording heads described above are, for example, 8 at 2.5 lines / mm for calculator printers and 16 at 4 lines / mm for facsimile printers. It is manufactured by changing the pattern of the electrode, so the mask is different for each device, and the above-mentioned etching, sputtering, vapor deposition, etc. processes become complicated, resulting in frequent work mistakes and the like, resulting in poor product yield. There was a drawback to do.

In view of such drawbacks, the perspective view of FIG.
A printhead having a structure as shown in FIG. 3, which is a sectional view taken along the line XY in the drawing, has been proposed. In this case, a discharge element having a liquid discharge portion of the printhead and this are connected to the drive circuit described above. The external wiring portion includes the first substrate 7 and this substrate 7
Are separately provided on the second substrate 8 having an opening portion for fitting.

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

Further, on the second substrate 8, a number of external wirings 14 forming the above-mentioned external wiring portion are provided corresponding to the above-mentioned lead electrodes 11.

In particular, as shown in detail in FIG. 3, the lead electrode 11 and the external wiring 14 are connected by wire bonding via the wire 9.
The bonding portions at both ends of are sealed with a sealant 15 in order to improve the reliability of the connection.

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

(1) Since the sealant 15 swells more than the ejection surface of the orifice plate 12, it is impossible to reduce the distance between the ejection surface and the recording paper to improve the recording quality.

(2) When the above distance is reduced, the sealant 15 rubs the recording surface of the recording paper to lower the printing quality, and the sealant 15 is worn to reduce the connection reliability.

(3) The sealant 15 may adhere to the orifice plate 12, and the stress may deform the orifice plate 12.

(4) Since the pitch between the connecting parts cannot be narrower than about 140 μm at present, the discharge element 13 has four colors integrated (24 ×
It is difficult to deal with the case of multiple dots such as 4 dots) and high density dots.

(5) There are many design restrictions such as the area of the bonding pad and the pattern arrangement around the pad, damage to the pad, stress on the wire 9, and the like.

(6) Since it takes about 0.3 to 1 second to bond at one location, the connection work takes time in the case of a multi-dot discharge element, etc., resulting in poor production efficiency and high cost.

(7) Product yield is poor.

By the way, an m × n matrix driving method is widely used as a method of driving such a recording head, particularly a recording head of a large number of dots, as a method capable of reducing the number of wirings and reducing the size of the head. For example, the fourth
The configuration is as shown in the figure.

That is, each heating resistor 10 is divided into n blocks for every m (four in this case), one end of each is connected in parallel to the common block selection switches BS1 to BSn, and the other end is in the block. Select switch S1 to select
Diode for backflow prevention in signal lines l1 to l4 connected to S2
Connected via 16.

As described above, in the matrix drive type driving circuit, the diodes 16 are connected to the respective heating resistors 10, and this connection is shown in FIG. 5 by using the diode array chip in which the above-mentioned aggregate of the diodes 16 is provided. The mounting structure is as shown.

That is, the diode array chip 18 is provided on the second substrate 8 of the recording head described above between each of the external wirings 14 described above and each of the second external wirings 17 connected to the flexible cable (not shown), and the diode array chip 18 is provided. The connection terminals of the array chip 18 and the external wirings 14 and 17 are connected to each other by a method such as wire bonding via the wire 9 described above.

However, in such a structure, the above-mentioned discharge element 1
3. In addition to the connection between the external wirings 14, the diode array chip 18 is connected to the external wirings 14 and 17 so that the number of connection points becomes extremely large, resulting in an increase in man-hours, a decrease in product yield and an increase in cost. Invite. In addition, a space for disposing the diode array chip 18 is required on the substrate 8, and the recording head becomes large accordingly.

Such a drawback is the same when connecting a transistor array instead of a diode array.

Further, the above-mentioned drawbacks and the above-mentioned drawbacks are not limited to the above-described liquid jet recording heads, and are applicable to all the liquid jet recording heads of the type described first.

[Objective] The present invention has been made in view of the above-mentioned drawbacks of the related art and the background art, and can achieve miniaturization and reduction of production cost.
Moreover, it is an object of the present invention to provide a liquid jet recording head which is excellent in reliability and can perform recording with high quality.

[Summary of the Invention] In order to achieve the above object, in a liquid jet recording head according to the present invention, a plurality of energy generators that generate energy used for ejecting a liquid, and the plurality of energy generators are electrically connected to each other. A plurality of electrodes that are electrically connected to each other, and the plurality of electrodes extend to both ends of the substrate, and the plurality of energy generators of the substrate are arranged. A discharge element having a discharge surface in which a plurality of discharge ports for discharging a liquid in a direction facing the upper surface are provided corresponding to the plurality of energy generators, and an electric signal is applied to each of the plurality of energy generators. An external wiring member in which a plurality of wirings for arranging are arranged, and the plurality of electrodes and the plurality of wirings in the direction along the ejection surface are electrically connected at both ends of the substrate. And a flat functional element component for electrical connection, and the ejection surface and the upper surface of the functional element component have substantially the same height in the direction in which liquid is ejected from the plurality of ejection ports. did.

[Embodiment] Hereinafter, details of an embodiment of the present invention will be described with reference to the drawings starting from FIG. In each drawing, the same or corresponding parts as those in FIGS. 2 to 5 are designated by the same reference numerals.

[First Embodiment] FIGS. 6 (a), 6 (b) to 8 illustrate the first embodiment of the present invention.

In this embodiment, as shown in FIG. 6A, a discharge element 13 composed of a first substrate 7 arranged in the opening of the second substrate 8 and each member provided on the upper surface thereof. The lead electrode 11 and the external wiring 14 provided on the second substrate 8 are connected through the diode array chip 18 shown in FIG. 6 (b) as shown in FIGS. 7 and 8. Adopted the structure. 8. FIG. 8 is a sectional view taken along the line XY in FIG.

 The details of each part will be described below.

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

As shown in FIG. 8, layered heating resistors 10 are provided on the upper surface of the substrate 7 in a number corresponding to the number of dots of the recording head.

As a material for forming the layer of the heating resistor 10, almost any material can be adopted as long as it can generate desired heat when energized.

Specific examples of such a material include tantalum nitride, nichrome, silver-palladium alloy, silicon semiconductor,
Alternatively, hafnium, lanthanum, zirconium, titanium, tantalum, tungsten, molybdenum, borides of metals such as niobium, chromium, vanadium, etc. are preferable.

Among these materials constituting the heat-generating resistor 10, metal borides can be particularly mentioned as excellent ones. Among them, hafnium boride has the most excellent characteristics, and then zirconium boride, Lanthanum boride, tantalum boride,
The order is vanadium boride and niobium boride.

The heating resistor 10 is formed on the substrate 7 by using the above-mentioned materials by a method such as electron beam evaporation or sputtering.

Further, on the upper surface of the substrate 7, layered lead electrodes 11 connected to both ends of each heating resistor 10 are formed. This lead electrode 11 is a material that can form a dense and pinhole-free inorganic insulating layer on its surface, for example, Al, Ta, Ti, Mg, Hf, Z.
It is formed on the substrate 7 by a method such as vapor deposition using r, V, W, Mo, Nb, Si or the like or an alloy thereof.

Further, each lead electrode 11 is formed such that the end portion on the side opposite to the heat generating resistor 10 extends to the vicinity of both end portions of the substrate 7, and a junction for connecting to the diode array chip described above is formed on this end portion. A metal (bump) 19 is provided. The bonding metal 19 is formed on the outer end of the lead electrode 11 by using gold, copper, solder (Pb-Sn), Al or the like by a method such as plating or vapor deposition.

Further, an orifice plate 12 having a long U-shaped cross section is provided on each heating resistor 10 and a portion of each lead electrode 11 excluding the outer end portion. An ejection port 12a for ejecting the ink droplet D is formed at each of the positions facing the heating resistor 10.

The orifice plate 12 is a metal plate (metal plate formed by electroforming) formed by plating with a noble metal such as nickel, copper, chromium, or cobalt, or a compound thereof such as a phosphide, a photosensitive film, a photosensitive glass, or the like. And is fixed on the substrate 7 by a method such as bonding with an epoxy-based or silicon-based adhesive.

It should be noted that each heating resistor 10 and each lead electrode 11 are covered by the orifice plate 12 on the substrate 7 including the portion excluding the outer end portion of each lead electrode 11 and each heating resistor 10 and the lead electrode 11 are covered.
A protective layer (not shown) that protects 11 is formed as necessary.

Materials for forming this protective layer include inorganic oxides such as SiO ₂ , inorganic nitrides such as Si ₃ N, titanium oxide, vanadium oxide, niobium oxide, molybdenum oxide, tantalum oxide, tungsten oxide, chromium oxide, zirconium oxide. , Transition metal oxides such as hafnium oxide, lanthanum oxide, yttrium oxide, and manganese oxide, and metal oxides such as aluminum oxide, calcium oxide, strontium oxide, barium oxide, and silicon oxide, and their composites, silicon nitride, aluminum nitride , Boron nitride, tantalum nitride and other high resistance nitrides, and composites of these oxides and nitrides, as well as semiconductors such as amorphous silicon and amorphous selenium, even if they have low resistance in bulk, sputtering method, CVD
Examples of the thin film material that can increase the resistance in the manufacturing process such as a vapor deposition method, a vapor deposition method, a gas phase reaction method, and a liquid coating method.

Further, a second protective layer is formed on the protective layer as needed. As the forming material, Al, Ta, Ti, Zr, Hf, V, Nb,
Oxides of metals such as Mg, Si, Mo, W, Y, La and their alloys,
Carbides, nitrides, borides, etc. are used.

A discharge element 13 is constituted by the above-mentioned parts and the substrate 7.

On the other hand, the second substrate 8 is formed of a sintered body such as ceramic or alumina.

A large number of external wirings 14 are formed on the substrate 8 so as to face the lead electrodes of the ejection element 13 described above. The external wiring 14 is, for example, silver-palladium, silver-palladium-platinum, gold-platinum, gold-palladium, gold, silver,
It is formed from a thick film printing material for conductors such as silver-platinum.

Further, as the board 8 and the external wiring 14, a printed wiring board in which these are integrated may be used. In this case, a paper phenol plate, a glass epoxy plate, a paper epoxy plate, a glass polyimide plate, a glass BT resin plate or the like is used as the printed circuit board material, and copper is mainly used as the wiring material.

Further, a bonding metal 19 similar to that described above is formed on the end portion of each external wiring 14 on the side facing each lead electrode 11 by using the same material and method as described above.

On the other hand, on both sides of the same diode array chip 18 having a flat rectangular parallelepiped shape as a whole, lead wires 20 connected to the anode and cathode of each diode (not shown) provided in the diode array chip 18 are provided. Is provided so as to project. This lead wire 20 is made of copper, copper alloy, Fe
-Ni-based alloy or the like, and at least the tip portion connected to the lead electrode 11 and the external wiring 14 described above is made of a thin film formed by plating or vapor deposition of gold, tin, copper, solder, aluminum or the like. It is covered.

The type of the joining metal 19 described above is selected according to the type of metal and the connecting method of the connecting portion of the lead wire 20.

In the above configuration, the discharge element 13 and the external wiring 14
For connection, the diode array chip 18 is arranged between the first and second substrates 7 and 8 and each lead wire 20 on one side of the chip is connected to the first as shown in FIGS. 7 and 8. Bonding to each lead electrode 11 on the substrate 7 via the bonding metal 19, and bonding each lead wire 20 on the other side of the chip to each external wiring 14 on the second substrate 8 via the bonding metal 19. Performed by. Examples of the above-mentioned bonding method include thermocompression bonding, eutectic, reflow, ultrasonic wave and the like.

As described above, according to this embodiment, since the discharge element 13 and the external wiring 14 are connected via the diode array chip 18, the following advantages can be obtained.

(1) Since the connecting portion (diode chip array 18) is flat and the protrusion amount 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 to improve the printing quality. .

(2) Even if the distance is reduced, the connection portion does not hit the recording paper, so that the connection reliability is improved.

(3) The pitch between the connection portions can be made narrower than the conventional 140 μm, and it is possible to cope with the multi-dot and high-density dot of the ejection element 13.

(4) Since the connection can be collectively performed in a short time, the production efficiency is improved.

(5) The number of connecting points is remarkably smaller than the conventional one, and the total number of steps is reduced.

(6) The space for the diode array chip, which was conventionally provided on the second substrate 8, is eliminated, and the recording head can be miniaturized accordingly.

In place of the diode array chip of the present embodiment, the above connection is made via other electronic components that form a part of the drive circuit of the ejection element, for example, the transistor array chip of the driver or other electronic components. The same effect as described above can be obtained.

[Second Embodiment] FIGS. 9 to 11 illustrate a second embodiment of the present invention.

In this embodiment, a so-called flip-shaped diode array chip 18 shown in FIG. 9 is used in place of the diode array chip 18 of the first embodiment described above.

This diode array chip 18 has a flat rectangular parallelepiped shape as a whole, and at both end portions along the longitudinal direction of the bottom surface thereof, as described above, connected to the anode and cathode of each diode (not shown) provided in the chip. The joining metal 19 is mainly provided by soldering by means of a method such as screen printing or metch.

Further, in the case of this embodiment, the ejection element 13 on the first substrate 7 and the external wiring 14 on the second substrate 8 are constructed in substantially the same manner as in the above-mentioned first embodiment, but the lead electrodes 11 and The difference is that the bonding metal 19 is not provided on the end of each external wiring 14.

As shown in FIGS. 10 and 11, the discharge element 13 and the external wiring 14 are first connected to the diode array chip 18 first.
And the second substrates 7 and 8 so as to straddle each of the bonding metal 19 on one side of the diode array chip 18 on the end of each lead electrode 11 and the bonding metal 19 on the other side. It is carried out by placing it on the end portion of each external wiring 14 and then joining each joining metal 19 to each lead electrode 11 and each external wiring 14 by a method such as reflow.

With the configuration of this embodiment as described above, the same effect as that of the above-described first embodiment can be obtained.

[Third Embodiment] FIG. 12 illustrates a third embodiment of the present invention.

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

Further, the diode array chip 18 is almost the same as that of the first embodiment described above, and is formed in an elongated rectangular shape having a length corresponding to all the discharge elements 13, and the number of the diode arrays chips 18 corresponding to all the discharge elements 13 is provided inside. Diodes are provided, and lead wires 20 connected to the anode and cathode of each of the diodes are provided on both sides in the longitudinal direction so as to project.

Then, similarly to the above, each lead wire 20 on one side is connected to each lead wire 11 of each discharge element 13, and each lead wire 20 on the other side is connected to each external wire 14 on the second substrate 8. As a result, each ejection element 13 and the external wiring 14 are connected via the diode array chip 18.

As described above, the present invention can be applied to the case of a multi-head, and the same effect as described above can be obtained. In this case, in particular, a large effect can be obtained in that the number of steps can be reduced and the production efficiency can be improved by performing the connection at once.

[Effect] As is apparent from the above description, according to the liquid jet recording head of the present invention, a plurality of electrodes and external wiring members respectively connected to a plurality of energy generators used for ejecting liquid of the ejection element. The plurality of wirings are connected by a flat functional element component in a direction along the ejection surface of the ejection element, and the height of the upper surface of the functional element component is substantially the same as the ejection surface, so that the ejection element substrate The amount of protrusion from the ejection surface of the connection portion of the functional element parts of the electrode and the wiring at both ends is small. As a result, even if the distance between the sheets is reduced, assuming that the recording paper faces the ejection element in a flat state, the connecting portion between the electrode and the wiring does not hit the recording surface of the recording paper and rub the recording surface, It is possible to perform high-quality recording and improve the reliability of the connection of the ejection elements.

Further, since the electrodes and the wiring are connected through the functional element parts, the number of connection points can be significantly reduced as compared with the conventional one,
The number of assembly steps can be reduced. Further, it is possible to reduce the size of the head by omitting the space occupied by the conventional functional element parts.

Furthermore, since the plurality of electrodes connected to each of the plurality of energy generators of the ejection element extend to both ends of the substrate, the electrodes are provided so as to extend between one end of the substrate as compared with the case where the electrodes are provided to extend to one end of the substrate. The pitch can be doubled, and the electrode and the wiring can be easily and reliably connected. On the contrary, the number of electrodes can be doubled without changing the pitch between the electrodes, and the excellent effect of being able to cope with a large number of dots and high density dots of the ejection element is obtained.

[Brief description of drawings]

1 is a plan view of a conventional liquid jet recording head, FIG. 2 is a perspective view of an essential part of a recording head according to the background art, FIG. 3 is a sectional view taken along line XY of FIG. 2, and FIG. 2 is a circuit diagram of the drive circuit of the recording head of FIGS. 2 and 3, FIG. 5 is a perspective view showing a mounting structure of a diode array chip of the recording head according to the background art, and FIGS. 6 (a) and 6 (b). ~ Fig. 8 illustrates the first embodiment of the present invention. Fig. 6 (a) is a perspective view of the recording head before the diode array chip is connected, and Fig. 6 (b) is a perspective view of the diode array chip. FIG. 7 is a perspective view of the recording head after connection, FIG. 8 is a sectional view taken along line XY of FIG. 7, and FIGS. 9 to 11 are for explaining the second embodiment. The figure shows a perspective view of a diode array chip,
10 is a perspective view of the recording head, FIG. 11 is a sectional view taken along line XY of FIG. 10, and FIG. 12 is a perspective view of the recording head according to the third embodiment. 7,8 ... Substrate, 10 ... Heating resistor 11 ... Lead electrode, 12 ... Orifice plate 13 ... Discharge element 14 ... External wiring 18 ... Diode array chip 19 ... Joining metal, 20 ... Lead line

Claims (6)

[Claims] 1. A substrate having an upper surface on which a plurality of energy generators that generate energy used to eject a liquid and a plurality of electrodes that are electrically connected to the plurality of energy generators are arranged. The plurality of electrodes extend to both ends of the substrate, and the plurality of ejection ports for ejecting liquid in a direction opposite to the upper surface of the substrate on which the plurality of energy generators are arranged have a plurality of ejection ports. A discharge element having a discharge surface provided corresponding to each of the energy generators, an external wiring member having a plurality of wirings for applying electric signals to the plurality of energy generators, respectively, A flat functional element component for electrically connecting the plurality of electrodes and the plurality of wirings in the direction along the surface at each of both ends of the substrate, and Liquid jet recording head in which the ejection surface in a direction in which the liquid from the mouth is discharged and the upper surface of the functional element part and having substantially the same height. 2. The liquid jet recording head according to claim 1, wherein the functional element component is a diode array chip. 3. The liquid jet recording head according to claim 1, wherein the functional element component is a transistor array chip. 4. The liquid jet recording head according to claim 1, wherein the energy generator is a heating element that generates thermal energy as the energy. 5. The liquid ejecting apparatus according to claim 1, wherein the external wiring member is provided with an opening, and the ejection element is arranged in the opening. Recording head. 6. The liquid jet recording head according to claim 1, wherein a plurality of the ejection elements are arranged in parallel.