JPS6124191B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet recording device, and particularly to a method for manufacturing a head portion thereof.

Recently, inkjet recording devices have been attracting attention in place of conventional impact type recording devices, and a number of publications have been made. FIG. 1 shows an example of such an ink droplet ejecting head 1, in which an ink chamber 2 is formed inside.
This ink chamber 2 is connected by a tube 3 to an ink supply source. A nozzle 4 is formed at the center of the front surface of the ejection head 1 and is connected to an ink chamber 2. The rear part of the injection head 1 is composed of a diaphragm 5, which forms the rear wall of the ink chamber 2 and a piezoelectric vibrator 6.
is fixed to this diaphragm 5. Now, when a pulsed electric field is applied to the piezoelectric vibrator 6, the diaphragm 5 is deformed and the volume of the ink chamber changes, causing the pressure of the ink to rise and eject as ink droplets from the nozzle. Heads with this type of structure are relatively large in size, and have a large number of nozzles arranged closely together.
When using a multi-nozzle ink ejection head,
Problems arise in terms of miniaturization, cost, reliability, etc.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a small, reliable, and inexpensive head.

Another object of the present invention is to provide a new head structure particularly suitable for multi-nozzle heads with high nozzle density as described above.

A method for manufacturing a head of an inkjet recording device according to the present invention includes forming a metal layer on each joint portion of a pair of substrates, joining the substrates by heat welding the metal layers, and forming a pressure chamber between the substrates filled with ink. and a method for manufacturing a head of an inkjet recording device, which has a nozzle communicating with the pressure chamber and is equipped with an electro-mechanical conversion element corresponding to the pressure chamber.
On the one substrate, a metal solder layer for bonding the substrate is formed on an outer portion of the contour of the pressure chamber and nozzle corresponding shaped portion, a metal protrusion is formed on the contour portion along the contour line, and a metal protrusion is formed on the contour portion along the contour line. A metal solder layer for bonding the substrates is formed on the outer portion of the contour on the other substrate, and then the pair of substrates are bonded by heat welding the metal solder layers for bonding, and the pressure is applied between the substrates. While forming a chamber and a nozzle,
It is characterized in that an extension surface of the bonding surface of the metal layer intersects the protrusion.

This will be explained below with reference to the drawings.

FIGS. 2a and 2b are basic diagrams for explaining the head configuration of the present invention, and 11 is a substrate made of glass or the like;
12, 13, and 14 are internal ink chambers (in particular, 13 is a compression chamber for causing a volume change by a piezoelectric vibrator, and 14 is an ink reservoir). Reference numeral 15 denotes a part that will become a nozzle, and to create this shape, the shaded part is plated with Au and Sn 16 to a thickness of about 10 μm to several 100 μm. For example, after plating the entire surface of one side of the board,
It can be easily created using known techniques such as resist coating, photoetching, etc.

FIG. 3 shows a method of assembling a head using the present invention. A lower substrate 11 plated with Au and Sn as shown in FIGS. 2a and 2b and an upper substrate 21 plated with Au and Sn on the entire surface or in a shape symmetrical to the lower substrate are stacked and the whole is heated to 400° to 500°C. Then Au and Sn
The metal part melts and forms a strong Au-Sn eutectic. As a result, the upper and lower plates are completely joined, and the Au
The area surrounded by Sn plating forms a space for an internal ink chamber, a nozzle, etc. Note that 22 is a hole for supplying ink to the internal ink chamber, and is connected to an ink supply source through a pipe 23 or the like. 24 again
is a piezoelectric vibrator fixed directly above the ink chamber 13 in FIG. 2, and deforms the substrate 21 by an electric field to compress the ink chamber 13. Conventionally, there have been proposals to form internal ink chambers, nozzles, etc. by etching a ceramic substrate, a glass substrate, etc. as a multi-nozzle ejection head, but the present invention has improved reliability compared to these methods. is very advantageous.

The above is the basic configuration of the present invention.
A detailed explanation of Sn eutectic bonding and a further improved head construction method are presented. Figure 4 a and b are
The Au-Sn eutectic bonding method is shown in Figures 2 and 3.
2 shows a part of the cross section of the head shown in the figure. Cr and Au vapor deposited film 31 that serves as a base for applying Au and Sn plating to the lower glass substrate 11 and the upper glass substrate 21
form. This vapor-deposited film is once applied to the entire surface of the substrate, and a pattern required for the nozzle and the like is formed by a photo-etching method such as resist coating and exposure.

Next, Au plating 32 and Sn plating 33 are applied on the vapor deposited film 31 of the lower glass substrate at a weight ratio of approximately 8:2, and the total thickness t is several tens of micrometers to several hundred micrometers.
(This is an appropriate value depending on design values such as the size of the tip of the nozzle 15 and the size of the compression chamber 13 in FIG. 2).

Furthermore, gold plating 34 is applied on the vapor deposited film 31 on the upper glass substrate, which is slightly inward from the pattern symmetrical to the lower glass substrate.
Thickness t' (= t + several μm to several tens of μm) so that it is located inside the Au plating 32 and Sn plating 33 parts.
give to These upper and lower glasses are stacked as shown in b, and pressure is applied from above and below to crush the gold-plated 34 part by the difference in thickness between t' and t.After this part is pressed together, the whole is heated to 400℃ to 500℃. The parts of the Au plating 31, the Au plating 32, the Au plating 34, and the Sn plating 33 are melted and become solid Au.
- Forms Sn eutectic and joins the upper and lower glass.
At this time, the Au plating portion 34 serves as a stopper, preventing the Au-Sn eutectic from flowing inward from the Au plating portion, and the shape of the space 35 is maintained perfectly. (The space 35 has a width of several tens, especially at the tip of the nozzle.)
Since the shape is micrometer and requires precision, accuracy is maintained compared to the method explained using FIG. 3. ) FIG. 5 shows an example in which the piezoelectric vibrator 24 shown in FIG. 3 is integrally formed as a further improved head construction method. A common electrode 42 is formed by vapor deposition or the like on the head 41 prepared by the method shown in FIGS. 2 to 4, and a film 43 of, for example, ZnO is uniformly deposited thereon by means such as sputtering. ZnO is known as a good piezoelectric material,
Moreover, since the film can be made thinner or thicker by means such as vapor deposition or sputtering, when the head is made into a multi-nozzle structure as in this embodiment, it is a very advantageous method since the drive piezoelectric vibrator can be fabricated all at once. Now, on this ZnO film, a counter electrode 44 is formed by vapor deposition or the like at a location corresponding to the position of the compressed ink chamber 13 in FIG. 2.

Since the amount of deformation of the substrate 21 for ejecting ink may be minute, even if an electric field is applied between the electrodes 42 and 44, it will not affect the portions to which no electric field is applied.

Note that the Au--Sn eutectic bonding method of the present invention can also be applied to bonding plates on which ink chambers and nozzles have been formed by etching or the like.

According to the present invention, a pair of metals are joined by forming a metal solder layer on both substrates and heat welding the metal solder layer. After bonding, the extended surface of the welding surface of the metal solder layer intersects with the protrusion of the metal. Such a metal protrusion is formed on the side of the pressure chamber or the ink flow path of the nozzle that comes into contact with ink, and a metal joint is formed on the outside thereof. Therefore, even if the pressure chamber or nozzle is filled with ink, the ink will not come into direct contact with the joint surface and will always be blocked by a metal protrusion, so the joint will be attacked by the ink and the joint will be damaged. It has very high reliability and will not peel off even if highly reactive ink is used or the vibration of the electro-mechanical vibration element is high frequency.

[Brief explanation of the drawing]

FIG. 1 shows an example of the configuration of a head of a conventional inkjet recording device. Figures 2a and 2b are basic explanatory views of the head of the inkjet recording apparatus of the present invention, and b is a cross section taken along line AA' of a. 3a and 3b are assembly diagrams of the head of the inkjet recording apparatus of the present invention. Figure 4 a, b
1 is a sectional view showing a method of assembling a head of an inkjet recording apparatus according to the present invention. FIGS. 5a and 5b show an example of the head configuration of a further improved inkjet recording apparatus of the present invention. DESCRIPTION OF SYMBOLS 1...Head, 2...Ink chamber, 3...Pipe, 4...Nozzle, 5...Vibration plate, 6...Piezoelectric vibrator, 11...Substrate,
12, 13, 14... Ink chamber, 15... Nozzle, 1
6...Au and Sn plating, 21...substrate, 22...hole,
23... Pipe, 31... Cr and Au vapor deposited film, 32...
Au plating, 33...Sn plating, 34...Au plating,
35... Space, 41... Head, 42... Electrode, 43...
ZnO sputtered film, 44...electrode.

Claims (1)

[Scope of Claims] 1. A metal layer is formed at each joining portion of a pair of substrates, and the substrates are joined by heat welding of the metal layers, and the space between the substrates is communicated with a pressure chamber filled with ink and the pressure chamber. A method for manufacturing a head of an inkjet recording device in which a nozzle is formed and an electro-mechanical transducer is provided corresponding to the pressure chamber, the one substrate is provided with an outer portion of the outline of the shaped portion corresponding to the pressure chamber and the nozzle. A metal solder layer for bonding the substrates is formed on the contour portion, a metal protrusion is formed along the contour line, and a metal solder layer for bonding the substrates is formed on the other substrate outside the contour. After that, the pair of substrates are bonded by heat welding the metal solder layers for bonding, and the pressure chamber and nozzle are formed between the substrates, and the extension surface of the bonding surface of the metal layer is exposed to the protrusion. 1. A method of manufacturing a head for an inkjet recording device, characterized in that the head is made to intersect with the head of the inkjet recording device.