JPS6218354B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording head of an inkjet recording device used in a printer or the like, which performs recording by jetting ink in accordance with an input signal.

Several systems have already been proposed for inkjet recording devices. One of these methods is to place a piezo element on one wall of the ink chamber of the recording head, and apply a voltage pulse as a recording signal to the piezo element to generate ink. Recently, this method has attracted particular attention because it can be realized with a simple configuration by increasing the liquid pressure of indoor ink and ejecting ink from a nozzle.

According to one proposal, using the above principle, glass,
Multiple ink chambers and nozzles are formed on a substrate made of ceramic or the like by etching, etc., and another substrate on which piezo elements are arranged is superimposed on this substrate and welded.
It has been shown that the recording head can be constructed by fixing the recording head by a method such as adhesion. An example of such a recording head is shown in FIG. Reference numeral 1 denotes a substrate made of glass, ceramic, etc., on which portions corresponding to an ink reservoir 2, a pressure chamber 3, an ink jet flow path 4, a nozzle 5, etc. are formed as a series of shallow grooves by etching or the like. Then, another relatively thin substrate 6 made of glass, ceramic, etc. is stacked and fixed on top of the substrate 1, and a piezo element 7 is arranged on the substrate 6 at a portion corresponding to the pressure chamber 3 of the substrate 1. Fix it. 20 is an ink supply port. In such a configuration, when a voltage according to an input signal is applied to the piezo element 7, the thin substrate 6 deforms inward due to interaction with the piezo element 7, increasing the ink liquid pressure in the pressure chamber 3 and releasing ink from the nozzle. Spray drops.

Such a recording head has a great advantage in that it is possible to integrate multiple pressure chambers and nozzles in a small area, making it easy to obtain a multi-nozzle head. Manufacturing problems exist in order to obtain a suitable head. That is, the substrate 6 is superimposed on the substrate 1 and fixed. Conventionally, methods such as direct welding of the substrates to each other or bonding with adhesive have been considered, but in general, the substrate 6 is stacked on the substrate 1 and fixed. The depth of the groove is several 10 μm to several 100 μm, the width of the nozzle part 5 is 10 to 100 μm, and the pitch between the nozzles 5 is
The diameter is about 50 to 500 μm, depending on the number of stacks. In the case of direct welding, there are problems such as deformation of the nozzle 5 or flow path 4, drooping, and sagging of the substrate 6 in the pressure chamber 3 or ink reservoir 2 part. Questions have arisen regarding the materials of the substrates 1 and 2. That is, as an example, substrate 1
When considered as glass, when welding it to substrate 2, the temperature of both should be at least close to the softening point (500 to 600℃).
In this state, it is necessary to raise the substrate 1 to
It is necessary to bring the substrate 2 into complete contact with the substrate 2. For this purpose, the surfaces of substrates 1 and 2 that are overlapped must be smooth, but since there is a limit to achieving perfect smoothness due to manufacturing reasons, substrates 1 and 2 must be brought into close contact with each other using a certain amount of external pressure. Must be. Under such circumstances, deformation of the nozzle 5, etc. mentioned above, and sagging of the substrate 2 due to its own weight in relatively large areas such as the ink pool 2 occur, making it difficult to obtain a highly accurate head. be. Furthermore, it is necessary that the thermal expansion coefficients of the substrate 1 and the substrate 2 be exactly the same or very close to each other, and this significantly limits the material of the substrate 2 with respect to the substrate 1.

Furthermore, when adhesive is used, it is inevitable that the gap between the width of the groove, especially the nozzle portion 5, will be clogged due to adhesive extrusion and increase in flow path resistance. Furthermore, adhesives are difficult to put into practical use due to their long-term reliability and compatibility with recording inks (there is a risk of damaging adhesives such as oil-based inks).

An object of the present invention is to use glass that can be microfabricated as a substrate, form fine grooves on the glass substrate, and create a head with nozzles, pressure chambers, etc. formed in the grooves by overlapping it with another glass substrate. An object of the present invention is to provide a method for manufacturing an inkjet recording head that can obtain an inkjet recording head in which glass substrates are bonded to each other without destroying the shape of grooves formed with high dimensional accuracy.

In the method for manufacturing an inkjet recording head of the present invention, a glass substrate having grooves formed thereon is bonded to another glass substrate with the grooves sandwiched therebetween, and a plurality of grooves are formed in the grooves sandwiched between the pair of glass substrates. A nozzle, an ink ejection channel communicating with each of the plurality of nozzles, and a pressure chamber communicating with each of the ink ejection channels are formed, and a piezo element is mounted on each of the positions corresponding to the pressure chamber on the other substrate. In the method for manufacturing an inkjet recording head,
After forming a nichrome metal layer on the opposing surfaces of the one glass substrate and the other glass substrate in which the grooves are formed, the one glass substrate and the other glass substrate are stacked, and the The pair of glass substrates are bonded by melting and bonding the nichrome metals to each other, and the nozzle is inserted between the pair of glass substrates. It is characterized by forming an ink ejection flow path and a pressure chamber.

To explain the main points of the inkjet recording head of the present invention, an extremely thin nichrome metal layer formed on the surfaces of two glass substrates is heated by high frequency induction heating (using a well-known general high frequency induction heating device). The nichrome metal layers on the surface are welded together by heating and melting.The advantage of this is that the very thin layers on the substrate surface are bonded together, so the substrate itself does not deform at all, and nozzles, flow channels, etc. The shape of the substrate is maintained accurately, even if the coefficients of thermal expansion of the two substrates are different, the heated part is limited to a thin layer, so there are no restrictions on the material between the substrates, and the metal layer on the surface of the substrate is Since a uniform thickness can be obtained by vapor deposition or the like, it is possible to minimize nonuniform adhesion and extrusion caused by the amount of adhesive used when adhesive is used.

Next, the present invention will be described in more detail using specific examples. FIG. 2a shows an example of the recording head of the present invention. Reference numeral 1 denotes a glass substrate, for example, and the ink reservoir 2, pressure chamber 3, ink jetting channel 4, nozzle 5, etc. are shown in FIG. The portion is formed by a groove formed by etching or the like. Here, the plurality of pressure chambers 3 are formed at positions corresponding to the piezo elements 7, each pressure chamber 3 is communicated with an ink ejection channel 4, and each ink ejection channel 4 is communicated with a nozzle 5. ing. Then, for example, nichrome 11 is applied to a portion other than this groove or a part thereof to a thickness of several hundred Å.
Deposit to a thickness of ~ several μm. Then, on the surface of another relatively thin glass substrate 6, for example, nichrome 12 is vapor-deposited on the entire surface or on a portion corresponding to the nichrome-deposited portion 11 of the substrate 1, and the substrate 1 and the substrate 6 are
The vapor-deposited surfaces of the two are placed one on top of the other and guided into a high-frequency induction coil 13 of a suitable shape as shown in FIG. 2b. When this coil 13 is connected to a high frequency generator 14 of 1 KHz to 1 MHz and a high frequency current is passed therethrough, an induced current flows only in the nichrome deposited portions 11 and 12, rapidly heating and melting them and bonding them. Further, a piezo element 7 is fixed on the substrate 6 at a portion corresponding to the pressure chamber 3. In this process, it is desirable that the evaporation surfaces of substrate 1 and substrate 6 are in perfect contact with each other, but since there is a limit to the smoothness of the substrate due to manufacturing, in reality, a certain amount of load is applied to bond substrate 1 and substrate 6. 6 is required to be in close contact with each other. However, in this case as well, since the heated portion is limited to a thin layer, no deformation of the nozzle as described above occurs.
Furthermore, since the nichrome metal layer can be uniformly formed to a thickness of several μm or less, it can be said that there is no protrusion into the nozzle portion or the like. The materials of the substrate 1 and the substrate 6 do not need to be made of the same material because there is no need to take into account the coefficient of thermal expansion, etc., so there is a wide range of selection. However, since the present invention is characterized by partial heating of only the thin metal layer, it is natural that the substrates 1 and 6 are undesirable because they themselves have an induced current flowing through them. is preferably a non-conductor, and conventionally used glass can be used. Further, it is desirable that the metal layer formed on these substrates by vapor deposition or the like has good adhesion to the substrate and a relatively low melting point, and nichrome is suitable for glass substrates.

As explained above, in the method for manufacturing an inkjet recording head of the present invention, firstly, since a glass substrate is used, grooves constituting nozzles, pressure chambers, etc. can be formed easily and accurately. Since a nichrome metal layer is formed on the opposite surface of the glass substrate and the glass substrate to be bonded, by overlapping the pair of glass substrates and subjecting them to high-frequency induction heating, only the nichrome metal layer can be heated. Locally heated and melted, a pair of glass substrates can be bonded through this nichrome metal layer without changing the shape of the groove.

Because only the nichrome metal layer on the opposing surfaces of the pair of glass substrates is heated and melted by high-frequency induction heating, and there is no need to heat the entire glass substrate to a high temperature, the time required for bonding is very short.
Nozzles and pressure chambers can be formed in a short time with high processing accuracy and without changing the shape of the grooves formed on the glass substrate. Furthermore, since the pair of glass substrates are joined by welding the nichrome metal layers,
The ink does not cause peeling at the joints,
Excellent long-term bonding reliability. Therefore, even though the inkjet recording head is formed with a plurality of nozzles, pressure chambers, etc., the shape of the inkjet recording head is not deformed during head manufacturing, and the inkjet recording head is highly reliable and can be used for practical purposes. becomes possible.

[Brief explanation of the drawing]

FIG. 1 shows an example of a conventional recording head. Second
The figure shows an example of a recording head using the present invention. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Ink reservoir, 3... Pressure chamber, 4... Ink ejection channel, 5... Nozzle, 6...
...Substrate, 7...Piezo element, 11...Nichrome,
12... Nichrome, 13... High frequency induction coil,
14... High frequency generator, 20... Ink supply port.

Claims (1)

[Claims] 1 A glass substrate with a groove formed on the substrate surface is joined to the other glass substrate with the groove sandwiched therebetween, and a plurality of nozzles are connected to the groove portion sandwiched between the pair of glass substrates, and each of the plurality of nozzles communicates with the other glass substrate. In the method for manufacturing an inkjet recording head, an inkjet recording head is formed, in which an inkjet recording head is formed with a pressure chamber communicating with the inkjet flowpath, and a piezo element is mounted on the other substrate at a location corresponding to the pressure chamber, respectively.
After forming a nichrome metal layer on the opposing surfaces of the one glass substrate and the other glass substrate in which the grooves are formed, the one glass substrate and the other glass substrate are stacked, and the The pair of glass substrates are bonded by melting and bonding the nichrome metal layers to each other, and the nozzle is placed between the pair of glass substrates. 1. A method of manufacturing an inkjet recording head, comprising forming an inkjet flow path and a pressure chamber.