JPH03253346A - Ink jet printer head and its manufacture - Google Patents

Abstract

PURPOSE:To manufacture a uniform characteristic ink jet printer head at a low cost by a method wherein a silicone substrate having a groove and a recessed part which are interconnected with each other is provided as a structure part, the groove constitutes the structure part of a nozzle, the recessed part constitutes the structure part of an ink chamber, and a vibration plate is structured by a bottom surface part of the recessed part. CONSTITUTION:For instance, a plate is connected to a side wherein a groove 2 and a recessed part of a silicone substrate 1 are formed, an ink chamber 3 being constructed by the recessed part, and a nozzle is constructed by the groove part. Then, a piezoelectric element 7 or the like is connected to a bottom surface part of the recessed part, and the bottom surface part of the recessed part operates as a vibration plate 5. It is not required that the vibration plate is independently connected thereto. Further, the silicone substrate is easily finely worked by etching and becomes capable of being worked with excellent precision. Therefore, though a thickness of the vibration plate is thinned, treating on manufacture is simple, and an ink jet printer can be manufactured by good productivity at a low cost.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to an inkjet printer that ejects ink from a nozzle by changing the volume of the ink chamber using a diaphragm provided in the ink chamber. This relates to a manufacturing method.

<Conventional Technology> Inkjet printers have recently attracted attention because they can print on plain paper with low noise and can print in color. (Ink chef) recording methods can be broadly divided into continuous methods and on-demand methods.On-demand methods are becoming mainstream because they do not require ink collection and are suitable for smaller and cheaper devices. This on-demand method includes
There are mainly thermal type and piezoelectric type, and both differ in the method of ejecting ink. The thermal type uses ink boiling due to heat generation, and the piezoelectric type uses volume changes in the ink chamber due to vibration of a piezoelectric element. The piezoelectric type has the advantage that there are fewer restrictions on the physical properties of ink than the thermal type, and the size of ink droplets can be controlled by applied voltage.

However, it also has the drawbacks of low frequency response and the inability to narrow the arrangement pitch of the piezoelectric elements.

Inkjet nozzles used for piezoelectric ink ejection have been made of stainless steel or glass. In the case of stainless steel, punching and etching methods are used to manufacture the material, and in the case of glass, glass work and engraving methods are used. However, with these lengths, there are limits to miniaturization and dimensional accuracy is poor. Since the casing, nozzle, and ink chamber are manufactured separately and then assembled, the manufacturing precision and productivity of the ink printer head is poor, and the product is expensive.

On the other hand, as a method that can solve the above problem, a method has been proposed in which a minute through-hole used for a nozzle is precisely fabricated perpendicular to a silicon substrate using anisotropic etching technology. 464 and? SP3,921.916).

In addition, a method for manufacturing an inkjet printer head using silicon has been proposed by Kust E-Petersen (I EEE Tran5ac
tion on Electron Device
s ED-26 (1979), 1918). FIG. 4 shows a structural diagram of a throat for an inkjet printer by Petersen. The same figure (al is a top view, the same figure (b
1 is a sectional view taken along line AA', d is a sectional view taken along line BB', and fdl is a sectional view taken along line cc'.
The silicon substrate 1 in which the grooves are formed, the diaphragm 5 and the piezoelectric element 7 are joined in this order to form a button, which is manufactured as follows. A nozzle groove 2 is formed by isotropic etching on a silicon substrate 1 having a residue (110).

Next, an oxide film is formed on the surface of the silicon substrate 1 to prevent the nozzle groove 2 from being etched again. Further, after removing the oxide film in the portion where the ink chamber 3 and the front nozzle end 4 are to be formed, anisotropic etching is performed on the casing through which the silicon substrate 1 passes through the portion where the ink chamber 3 is to be formed.

During this anisotropic etching, the nozzle end surface 4 is (1
11) plane, and the front 4 of the nozzle end serves as a lens barrel by taking advantage of the slow etching speed of the (111) plane. An ink chamber 8 is formed by bonding a bottom plate 6 made of a thick lath plate and a diaphragm 5 made of a thin glass plate C (thickness 230 μm) to both sides of the silicon substrate 1 thus processed.Finally, the diaphragm 5 The piezoelectric element 7 is pasted on top and the ink introduction pipe 8 is inserted to complete the process.This solves the problem associated with nozzle processing.

<Problem B to be Solved by the Invention> One of the main components of a piezoelectric inkjet printer head is a diaphragm. Generally, a thin plate of glass or 7 stainless steel is used for this diaphragm, and is bonded to a substrate forming an ink chamber.

The thinner the diaphragm is, the easier it is to bend, the drive voltage for the piezoelectric element can be reduced, the span length can be shortened, and higher density can be easily achieved.

However, the thinner the diaphragm is, the more likely it is to warp or crack, and the more careful it is to handle and the more difficult it is to join.

In order to facilitate this bonding, there is a method of polishing the diaphragm to make it thinner after bonding, but problems such as the diaphragm cracking occur during polishing, which is not advantageous in terms of productivity and loss of contact.

Furthermore, since a large force is applied to the diaphragm by the piezoelectric element, sufficient strength is required for the bonding, and a technique for obtaining a strong bond is required.

In the method of processing the nozzle by anisotropic etching of silicon and making the front of the nozzle end a mirror surface of the (111) plane, the side surface 10 parallel to the nozzle end surface 4 of the ink chamber 8 shown in FIG. becomes a mirror surface on the (111) plane, but as shown in Fig. 4 [c
The side surface 9 perpendicular to this shown in FIG. As a result, if the span length D of the diaphragm 5 is large, the deflection characteristics of the diaphragm 5 will change.

Therefore, in order to make the deflection characteristics of each head uniform, it was necessary to keep the time for forming the through groove in the silicon substrate constant and to precisely align the thickness of the silicon substrate.

The present invention aims to solve these problems.

Means for Solving the Problems In order to achieve the above object, the present invention has a silicon substrate having grooves and recesses connected to each other as a constituent part, the grooves being a constituent part of a nozzle, The recess is a component of an ink chamber, and the bottom of the recess constitutes a diaphragm. The present invention provides an inkjet printer head that ejects ink from the nozzle by changing the volume of the ink chamber by vibration of the diaphragm provided in the ink chamber.

The present invention uses a (110) silicon single crystal substrate,
A protective film against the etching having a rectangular opening for forming the recess is formed on the substrate, and the long side of the opening is the intersection line of the (110) plane and the (111) plane perpendicular thereto. The groove and the recess are formed in the silicon substrate by subjecting the substrate to anisotropic etching so that the groove and the groove are formed on the short side of the opening.・Provide a method for manufacturing a top printer head.

Function> In the inkjet printer head of the present invention, for example, a plate is bonded to the side of the silicon substrate on which the grooves and recesses are formed, and the recesses form an ink chamber and the grooves form a nozzle. . A piezoelectric element or the like is connected to the bottom of the recess, and the bottom of the recess functions as a diaphragm, eliminating the need to separately bond the diaphragm. Furthermore, silicon substrates can be easily microfabricated by etching, making it possible to process them with high precision.

According to the manufacturing method of the present invention, as the etching time elapses, etching progresses in the depth direction of the substrate, and a (111) plane appears on the long side of the opening, forming a recess. The distance between the pair of side surfaces having the (111) planes is kept constant regardless of the etching time. this is,(
This is because the etching rate of the (111) plane is extremely slow compared to the etching rate of the (11O) plane. Therefore, the shorter span of the diaphragm formed by the bottom surface of the recess is formed to have a constant length regardless of the etching time, so that the deflection characteristics of the diaphragm can be made constant. Furthermore, since the groove is formed on the short side of the opening, when an inkjet printer head is manufactured by arranging a large number of nozzles, the inkjet nozzles can be arranged in the narrow direction of the ink chamber. Enables high-density production in one printer.

<Example> Embodiments of the present invention will be described with reference to FIGS. 1 to 3. FIG.

FIG. 1 is a structural diagram of the ink sheet printer head of this embodiment, where FIG. 1a) is a top view and fbl is an A-A
1c) is a sectional view along line BB', and fdl in the same figure is a sectional view along line cc'. FIG. 2 is a manufacturing process diagram of the inkjet printer head of this embodiment, and FIG. 8 is a perspective view of the vicinity of the nozzle groove 2 of this embodiment.

The method for manufacturing the inkjet printer head of this example will be explained below. A protective film 18 against etching is formed on the surface of a (110)J single crystal silicon substrate 1. The protective film 13 is a 5i02 thermal oxide film, Si3N4
A film or a boron-doped silicon film can be used, and in this example, a 5i02 thermal oxide film, which can easily form a transparent film, was used. Next, the protective film 18 on one side of the silicon substrate 1 is removed at a portion where the nozzle groove 2 and the through hole 11 are to be provided to form an opening. The shape of the opening was rectangular for both the nozzle groove 2 and the through hole 11, with the long side oriented in the <IT2> direction. Next, anisotropic etching is performed using an alkaline etching solution such as an ethylenediamine/pyrocatechol aqueous solution or a KOH aqueous solution (FIG. 2(a)). The depth of cutting and cutting was 40 μm. Next, in order to prevent the nozzle groove 2 from being reworked or damaged, a protection layer 13 is formed in an overlapping manner on the front surface of the substrate 1. This protective film is the same 5in2 thermal oxidation model as the previous protective film 13, and is integrated with the previous protective film (Fig. 2(b)). Next, the shape of the part where the ink chamber 3 is provided is a rectangle as before, and the long side is in the <112> direction (FIG. 2(C)). Next, as before, anisotropic etching is performed using an alkaline etching solution. Etching was stopped when a through hole was formed in the silicon substrate 1 (FIG. 2(d)).

As a result, a concave portion that will become the ink chamber 8 is formed, and the thickness of the bottom tube is approximately 40 μm, and this portion will become the diaphragm 5.

The remaining through hole 11 becomes an ink introduction hole.

After that, the etching protection film on the entire substrate 1 is removed,
This is joined to the bottom plate 6 and cut across the nozzle groove 2 (FIG. 2(e)). Glass, silicon, or the like is used for the bottom plate 6, and bonding is performed by thermal fusion using low melting point glass, electrostatic bonding, or the like. Through the above steps, the nozzle, ink chamber 8 and nozzle end frame 4 are formed. Finally, the piezoelectric element 7 is attached to the diaphragm 5.

In the manner described above, a nozzle for an inkjet printer having a square nozzle shape of 40 μm×40 μm and a diaphragm integrally formed with a thickness of 4 Q pe+ is manufactured. The thickness of this diaphragm is much thinner than that of conventional diaphragms, which had a maximum thickness of 150 μm.

The size of the nozzle may be selected depending on the diameter of the printed dot, and is approximately 20 to 100 μm. Furthermore, since the silicon surface repels ink, a thermal oxide film, Si3N, or a film may be used on the silicon surface to improve leakage.

In this example, the etching shape is rectangular and its long side is in the 112> direction, so the side surface 12 of the nozzle/groove and the side surface 9 of the ink chamber are perpendicular to the front surface of the silicon substrate 1. form a surface.

For this reason, the side surface 10 of the ink chamber undergoes etching in the direction perpendicular to the side surface 10 as the etching time progresses.
On the side surface 9, the machining/chipping in this direction does not proceed, and the length of the shorter span remains constant.

Since the deflection characteristics of the diaphragm are determined by the shorter span length D, variations in the deflection characteristics do not occur due to changes in the etching time or the quality of the etching solution.

Furthermore, since the nozzle width is similarly well controllable, the ink ejection characteristics can be made uniform depending on the nozzle shape.

Furthermore, at the same time as the nozzle groove 2 is etched, the through hole 11 is etched.
The diaphragm was formed by detecting the formation of the through hole 11 when etching the concave portion that will become the ink chamber 3 to the same depth. It is easy to control the thickness of the diaphragm and has high controllability.

It is also possible to continue etching even after the through holes are formed to form a thinner diaphragm.

In addition, a 3+02 thermal oxidation film, which is a protective film for coating and oxidation,
The 513N4 film, a boron-doped silicon film, has high etching resistance against alkaline nitching solutions, and it is also possible to perform etching while leaving only this film and use it as a diaphragm. In this case, the thickness of the diaphragm is approximately several .mu.m to several .mu.m.

<Effects of the Invention> The inkjet printer head of the present invention does not require a separate diaphragm to be joined, so even if the thickness of the diaphragm is reduced, handling during manufacturing is easy, productivity is high, An inkjet printer head can be manufactured at low cost.

Since the housing and the diaphragm have an integral structure, there is no problem of weak bonding strength of the diaphragm.

Furthermore, since it is possible to form a thin diaphragm, the driving voltage of the piezoelectric element can be lowered, and higher density can be achieved.

By using the manufacturing method of the present invention, the length of the diaphragm in the direction that affects the diaphragm's deflection characteristics can be kept constant regardless of the etching conditions, so there is no need to strictly align the thickness of the substrate, and the manufacturing conditions is easy to control, and diaphragms with uniform characteristics can be manufactured.

Furthermore, etching of a silicon single crystal substrate is easy. Therefore, it is possible to manufacture a lid for an inkjet printer with uniform characteristics at low cost.

[Brief explanation of drawings]

Fig. 1 is a structural diagram of an inkjet printer head according to an embodiment of the present invention, Fig. 2 is a manufacturing process diagram of this embodiment, Fig. 8 is a perspective view of the vicinity of the nozzle groove of this embodiment, and Fig. 4 is a conventional inkjet printer head. It is a structural diagram of an inkjet printer bend. 1: Silicon substrate, 2: Nozzle groove, 8: Ink chamber, 5: Two side surfaces of the diaphragm 9, 10: Side surface, 12: Side surface.

Claims (1)

[Claims] 1. In an inkjet printer head that ejects ink from a nozzle by changing the volume of an ink chamber by vibration of a diaphragm provided in the ink chamber, the silicon substrate has grooves and recesses that are connected to each other. 1. An inkjet printer head, wherein the groove is a component of a nozzle, the recess is a component of an ink chamber, and the bottom of the recess is a diaphragm. 2, (110) A method of forming the grooves and recesses in a silicon substrate by anisotropically etching a silicon single crystal substrate, the etching having a rectangular opening for forming the recesses on the substrate. A protective film is formed against the (110) plane, and the long side of the opening is perpendicular to the (110) plane.
11) The method of manufacturing an inkjet printer head according to claim 1, wherein the groove is formed on the short side of the opening so as to coincide with a line of intersection with a plane.