JPH064329B2 - Liquid jet head - Google Patents

Description

Detailed Description of the Invention

TECHNICAL FIELD The present invention relates to a liquid ejecting head that ejects liquid to form flying droplets for recording, and particularly to a liquid ejecting head in which an electrical connection portion between a liquid ejection substrate and a wiring member is sealed. Regarding the head. [Prior Art] A liquid jet recording method such as an ink jet recording method is extremely small in the generation of noise during recording and is capable of high-speed recording, and does not require a special process of fixing on so-called plain paper. In the point that can be recorded in
I've been interested recently. Among them, for example, Japanese Patent Laid-Open No. 54-51875, published in Germany
The liquid jet recording method described in (DOLS) 2843064 has a feature different from other liquid jet recording methods in that thermal energy is applied to a liquid to obtain a driving force for droplet ejection. is doing. 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 rapid increase in volume, and the action force based on the state change causes the liquid ejecting head portion tip end to move. Recording is performed by ejecting a liquid from an ejection port to form flying droplets and attaching the droplets to a recording member. In particular, the liquid jet recording method disclosed in DOLS 2843064 is not only very effectively applied to the so-called drop-on-demand recording method, but also the head portion is a full line type and has a high density multi-orifice. The liquid ejecting head can be easily embodied, so that a high-resolution and high-quality image can be obtained at high speed. Therefore, in the head portion of the apparatus applied to such a recording method, the ejection ports provided for ejecting the liquid and the thermal energy generating element communicating with these ejection ports for ejecting liquid droplets are provided. A liquid discharge port having a liquid flow path provided therein and an electrothermal converter as a means for generating thermal energy are provided. Further, as this type of liquid ejecting head, there is one in which a piezoelectric element is used as a pressure generating element. In such a head portion, an ejection port provided for ejecting a liquid and a communication port for these ejection ports are provided. And a liquid flow path including a piezoelectric element that generates a pressure for ejecting a droplet. Therefore, in the conventional recording apparatus using the liquid ejecting head as described above, a flexible wiring cable for connecting the drive circuit portion that supplies the electric signal for driving the electrothermal converter or the piezoelectric element of the liquid ejecting head. Up to the part
The wiring part of the recording head is provided so as to extend in the same substrate. In addition, a flexible cable for guiding an electric signal to the liquid ejecting head is introduced to a wiring pad portion provided on the head and then the connection pad of the flexible cable is crimped to the wiring pad portion, or a wire is used. After being bonded to each other by a method such as bonding, soldering, or thermocompression bonding, they are fixed to the liquid jet head. Furthermore, the substrate of the liquid ejecting head is different for each product according to each purpose, for example, in the case of a calculator printer, 2.
It was manufactured by changing the pattern of the wiring, the heating resistor and the piezoelectric element, such as 8 at 5 / mm and 16 at 4 / mm for FAX. FIG. 5 shows an example of such a conventional liquid jet recording head substrate. Here, 1 is a substrate of the liquid ejecting head, 2 is an electrode for guiding an electric signal, 3 is a heating element or a piezoelectric element on which an electrothermal converter or a piezoelectric element is formed, and 4 is a heating element or the piezoelectric element 3 is protected from a liquid. The protective film 5 formed for this purpose is a flexible cable for connecting to the drive circuit and the electrode 2 of the substrate 1. In such a conventional liquid ejecting head, there are many wiring wiring portions as in the area 6 shown in the figure, and thus the amount of substrate material required for one head increases. Moreover, since an expensive material such as Si is used as the substrate material, the cost of the liquid jet head increases. In addition, the increase in size of the substrate due to such unnecessary portions reduces the throughput in processes such as etching and sputter deposition, and hinders mass production. Further, since the mask is different for each product, the etching process and the sputter vapor deposition process are complicated, and the yield is significantly deteriorated due to work mistakes and the like. Further, even in the unnecessary portion, wiring short-circuits, bridges, etc. occur with the same probability as in the necessary portion, and even though it is an unnecessary portion, the yield of the product is deteriorated. [Background Art] From this point of view, an individual head member is obtained by dividing a substrate assembly provided with a plurality of substrate members each having an energy generating portion, and a main electrode (first electrode) 2) is provided on the electrode substrate member (external wiring member), and the head portion is attached to the external wiring member,
Further, a liquid jet head has been proposed in which the second wiring of the external wiring member and the electrode of the head portion are electrically connected. FIG. 6 and FIG. 7 show that the head portion (referred to as an ejection element) as described above as the background art of the present invention and the external wiring member are electrically connected in the direction along the ejection port surface of the head portion. An example of a configured liquid ejecting head is shown. Here, 11 is a discharge element obtained as described above, and a lead electrode (first wiring) electrically connected to the heating element 13 shown in FIG. 6 as an energy generator of the discharge element 11. In order to make an electrical connection between the signal electrode 12 (second wiring) 15 arranged on the external wiring member 14, a bonding wire 16 is mounted in this example, and the bonding is performed. The surrounding portion is covered with a sealant 17 to protect the enclosed portion and increase reliability. Reference numeral 18 is an orifice plate having a discharge port 19. Therefore, with such a configuration, it became possible to solve the above-mentioned conventional technical problems, but as a result of further study, it was found that there are the following problems to be solved. It was That is, in the liquid jet head connected and configured by using such an electrical connection method, the sealant 17 may rise and project from the front surface of the orifice plate 18 toward the liquid ejection side. If the distance between the ejection port 19 and a recording material (not shown) is not set wide, the raised portion of the encapsulant 17 contacts the recording material and rubs the surface of the recording material sheet to deteriorate the recording quality. Not only that, but sometimes the sheet is damaged. Further, if the distance between the recording material and the recording material is widened in consideration of safety, the print quality will be degraded. Furthermore, if the sealing agent peeled off by rubbing the sheet surface diffuses on the orifice plate 18, it may cause ejection failure by blocking the ejection port 19.
There is a possibility that the reliability of the head may be reduced. (Object) The object of the present invention is made in view of the problems of the related art and the problems to be solved by the background art as described above,
Protects the electrical connection part and wiring of the head from the liquid in which the head part and the external wiring member are electrically connected in the direction along the ejection port surface of the head part, and the strength in the vicinity of the connection part is enhanced. Accordingly, it is an object of the present invention to provide a liquid jet head which can improve the technical reliability of the electrical connection portion and improve the printing quality. SUMMARY OF THE INVENTION That is, the present invention has a substrate on which an energy generator and a first wiring electrically connected to the energy generator are arranged, and the energy generated by the energy generator is converted into a liquid. A head portion that ejects the liquid from the ejection port by operating, and an external wiring member that is a member separate from the head portion and that has a second wiring for supplying an electric signal to the head portion; The first wiring of the head portion and the second wiring of the external wiring member are electrically connected in a direction along a surface on which the ejection port is provided, and the head portion is provided. A part of the first wiring, a part of the second wiring of the external wiring member, and their electrical connection parts are integrally sealed, and the height of the sealed part is high. Characterized by a height of less than 2 mm . Embodiments Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows an embodiment of the present invention, which is a further development of the background art described above. In this example, when forming the ejection element (head portion) 21, first, a substrate formed of glass, ceramics, silicon, or the like is used.
A heating resistance layer or a piezoelectric element 23 which is an energy generator and a lead electrode 22 which is a first wiring are formed on 21A, and a protective layer (not shown) is formed on the upper surface thereof if necessary. In addition,
In forming the lead electrode 22, for example, a metal material such as aluminum, tantalum, titanium, magnesium, hafnium, zircon, vanadium, tungsten, molybdenum, niobium, or silicon can be used. It is formed by attaching it to a position. In addition, pad portions 22 formed on both ends of the lead electrode 22 in a portion that does not overlap with the orifice plate 28 on which the ejection ports 19 are arranged
For A, gold, silver-platinum, or silver-palladium alloy is formed on the electrode 22 as necessary by a method such as plating, screen printing or vapor deposition. Meanwhile, orifice plate
For No. 28, nickel, copper, chromium, cobalt or other noble metals, and further, for example, a phosphorus compound is electroplated, and this is bonded onto the substrate 21A with an epoxy adhesive or a silicon adhesive. Fix it. Note that the structure of the discharge element is not limited to this, and may be, for example, integrally formed of resin, or may have a double structure in which an orifice plate electroplated on a photosensitive film is laminated. . On the other hand, a metal plate 25 serving as an external wiring member in the form of a lead frame, on which the second wiring 25-1 is formed, is arranged on the element support base 24, and the discharge element is placed on the support base 24.
The adhesive 21 is adhered. As the adhesive, it is preferable to use a silver paste having a high thermal conductivity, silver epoxy, or an epoxy resin-based adhesive mixed with silica or alumina. On the other hand, a sintered body of alumina, aluminum nitride, silicon carbide, beryllium oxide or the like is suitable for the support base 24, and a metal plate 25 in the form of a lead frame is formed on the support base 24 with, for example, 42 alloy of iron-nickel alloy or copper. Form and paste,
Further, screen printing or the like is performed on the metal plate 25 by using a thick film printing material for conductor such as silver-palladium alloy, silver-palladium-platinum alloy, gold-platinum alloy, gold-palladium alloy, gold, silver, silver-platinum alloy. The second wiring 25-1
To form. The metal plate 25 will be connected to the second wiring 25-
It is also possible to attach it to 1. After the discharge element 21 is mounted on the support base 25 as described above, the electrode pad portion 22A of the first wiring 22 of the discharge element 21 and the second wiring 25-1 on the support base 24 are bonded. It is electrically connected by a wire 26. here,
The wire 26 is preferably a gold wire, an aluminum wire, an aluminum-silicon wire, or the like. FIG. 2 shows a state in which the discharge element 21 is mounted on the support base 25 in this way and further electrically connected.
Further, the pad 22A on the discharge element 21 in such a state
A frame lid-shaped sealing member 30 as shown in FIG. 3, for example, is covered from the portion where the above is arranged to the range limited by the outer peripheral portion of the element support base 24, and this is adhered so as to be airtight. The sealing member 30 is made of alumina, aluminum nitride, silicon carbide, beryllium oxide, or the like, and is made of ceramics as a sintered body. Its shape has a surface parallel to the orifice plate. If Further, it is preferable to use an epoxy-based or silicone-based adhesive as the adhesive. In this way, the space 35 obtained by the sealing of the sealing member 30 is filled with a dry and inert gas such as nitrogen, helium, or argon, so that the lead, which is the first wiring accommodated in the space 35, is formed. The pad portion 22A of the electrode 22, the second wiring 25-1 and the bonding wire 26 can be prevented from being corroded, and these portions can be protected by being separated from the outside. In addition, it is preferable that the upper surface side of the sealing member 30 which is in contact with the recording body is formed flat so as not to cause any trouble even if it comes into contact with the recording material during recording. Further, in order to improve the recording quality, it is desirable that the height L of the member 30 on the support base 24 is as low as possible, which is also related to the mounting of the bonding wire 26, but the height L is preferably 2 mm or less. FIG. 4 shows a finished product of the liquid jet head constituting member obtained in this way, and as is clear from this figure, the electrical connection portion is compact and completely protected, has high reliability, and is sealed. By setting the height of the stop member 30 to 2 mm or less, the distance between the ejection port 19 and the recording material can be reduced, and therefore the recording quality can be improved. In the above description, an inert gas is filled in the sealing member 30 as a suitable example, but the configuration of the present invention is not limited to this, and for example, the sealing range shown in FIG. The entire part can be molded with a mold resin of the same shape. The point is that the protection applied to the electrical connection part is formed so that the height of the sealing part 30 on the surface facing the recording material is 2 mm or less. What is achieved is a sealing member that can be used. [Effect] As described above, according to the present invention, the energy generator and the first wiring electrically connected to the energy generator are provided on the substrate, and the energy generator is generated. A head part for ejecting the liquid from the ejection port by applying the generated energy to the liquid, and a second wiring which is a member separate from the head part and which supplies an electric signal to the head part. An external wiring member, wherein the first wiring of the head portion and the second wiring of the external wiring member are electrically connected in a direction along a surface on which the ejection port is provided. And a part of the first wiring of the head portion and a part of the second wiring of the external wiring member,
These electrical connection parts are integrally sealed, and
Since the height of the sealed portion is 2 mm or less, it is possible to set the droplet flying distance between the orifice plate and the recording material to be short, thereby improving the printing quality. Not only is it possible to protect the electrical connection part and the wiring around it from the number of liquids ejected from the ejection port, it also helps to reinforce the connection part, and also the sealing member does not contact the recording material. Because you can
The reliability of the electrical connection can be improved.

[Detailed Description of Drawings]

FIG. 1 is a cross-sectional view showing an example of the configuration of the liquid jet head of the present invention, FIG. 2 is a perspective view showing a state before sealing the electrical connection portion, and FIG. 3 is sealing applied to the electrical connection portion. FIG. 4 is a perspective view showing an example of a member, FIG. 4 is a perspective view of a liquid jet head of the present invention, FIG. 5 is a plan view schematically showing an example of a head substrate of a conventional liquid jet head, and FIG. 6 is a background art. FIG. 7 is a perspective view showing an example of the connection form between the ejection element of the liquid jet head and the wiring board, and FIG. 7 is a cross-sectional view showing an example of the form of the seal provided on the electrical connection part. DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Electrode, 3,23 ... Heating element or piezoelectric element, 4 ... Protective film, 5 ... Flexible cable, 6 ... Area, 11,21 ... Ejection element (head part), 12, 22 ... Lead electrode ( 1st wiring), 13 ... Heating element, 14 ... External wiring member, 15 ... Signal electrode (second wiring), 16, 26 ... Bonding wire, 17 ... Sealant, 18, 28 ... Orifice plate, 19 ... Discharge port, 21A ... Substrate, 22A ... Pad part, 24 ... Supporting base, 25 ... Metal plate (external wiring member), 25-1 ... Wiring (second wiring), 30 ... Sealing member, 35 ... Space.

Claims (4)

[Claims] 1. A substrate having an energy generating body and a first wiring electrically connected to the energy generating body, wherein the energy generated by the energy generating body acts on a liquid, A head portion for ejecting liquid from an ejection port; and an external wiring member, which is a separate member from the head portion and has a second wiring for supplying an electric signal to the head portion, Part of the first wiring and the second wiring of the external wiring member
Of the first wiring of the head portion and one of the second wirings of the external wiring member are electrically connected to each other in the direction along the surface on which the ejection port is provided. A liquid ejecting head, characterized in that the part and these electrical connection parts are integrally sealed, and the height of the sealed part is 2 mm or less. 2. The liquid jet head according to claim 1, wherein the head portion is a head portion configured to eject ink on a side facing a substrate on which the energy generator is arranged. 3. The liquid jet head according to claim 1, wherein the energy generator is a heating element that generates thermal energy. 4. The liquid jet head according to claim 1, wherein the sealing is made of resin.