JPH0469249A - Ink jet printer head - Google Patents

Abstract

PURPOSE:To make it unnecessary to form an orifice at every pressure chamber and make it easy to manufacture a second plate and a position adjustment to the pressure chamber. CONSTITUTION:A slit 31 as a linear through groove is formed on a second plate 30 without supply passage layer. A partition 33 of a pressure chamber 9 of a first place 32 facing the slit 31 has a height lower than a peripheral part 20. In a state that the plates 32 and 30 are connected integrally, a clearance which opens in the direction of the whole periphery is formed between a tip of the partition 33 of the pressure chamber 9 and a back face of the second plate 30, which is made to be an ink supply passage 34 communicating an ink storage 11 with the pressure chamber 9. An ink jet printer head 29 deflects a pressure generated at a surface of a heat generating resistor 7 by the partition 33 of the pressure chamber 9 so as to eject ink drips from the slit 31. Thus, a manufacture of the second plate and a position adjustment to the pressure chamber of the first plate will be easy.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an inkjet printer head such as a bubble jet type or a piezo type.

2. Description of the Related Art In recent years, inkjet printer heads have been developed as printer heads that are quiet and capable of high-density printing. this is,
Ink droplets or ink vapor are ejected from an orifice using a predetermined pressure generating means and fixed on the printing paper.In addition to the piezo method that uses an electrostrictive element as the pressure generating means, there are also thermal types that use a heating element as the pressure generating means. A method such as a bubble jet method and a bubble jet method have been proposed. These methods can apply existing technology related to thermal heads, and are therefore expected to be a method for easily obtaining high-performance inkjet printer heads.

Here, a bubble jet type inkjet printer head is one in which a part of the ink filled in a pressure chamber behind an orifice is instantaneously heated and evaporated, and the pressure caused by the volume change of the bubbles formed is used to push ink droplets out of the orifice. It is designed to be discharged.

There are various types of bubble jet inkjet printer heads.
The inkjet printer head disclosed in the above publication has a structure in which a flat member with a long groove serving as an orifice is attached to a substrate that has a structure similar to that of existing thermal heads. By selectively driving the heating resistor to generate heat, bubbles are generated in the ink within a predetermined orifice, and ink droplets are ejected. Note that the generation and disappearance of such bubbles takes place in a minute time of about μs,
As the pressure of the ink rapidly rises and falls within this minute time, the ink ejected from the tip of the orifice becomes ink droplets and flies.

However, in the above-mentioned inkjet printer head, since the orifice has a straight tube shape, the pressure change of the ink acts in the front and back direction, resulting in excessive pressure loss.

Therefore, as devices that have solved this problem, there are devices disclosed in Japanese Patent Publication No. 63-6356, Japanese Patent Publication No. 63-6357, and Japanese Patent Publication No. 63-6358. For example, in the inkjet printer head disclosed in Japanese Patent Publication No. 63-6356, a flow path is formed that is bent at a substantially right angle at the heating resistor part, so that changes in ink pressure can favorably affect the jetting direction of ink droplets. That's what I do.

However, in an inkjet printer head with a curved flow path as described above, the direction of pressure change and the direction of flow during continuous ejection are asymmetrical with respect to the axis of the orifice, so the flight direction of the ejected ink droplets is It gets bent.

As a countermeasure to this problem, it has been proposed to displace the relative position of the pressure generating means with respect to the orifice, but the optimal value of this displacement varies depending on factors such as temperature changes and changes in ink viscosity due to aging. However, it is difficult to perform accurate fluid analysis, so it is not practical.

Furthermore, JP-A-58-8659 and JP-A-59-2
The inkjet printer head disclosed in Japanese Patent No. 07261 has a structure in which a pressure chamber partition having a shape surrounding the heating resistor is formed on a substrate on which the heating resistor is formed, and an orifice plate is bonded thereon. The flow path is located symmetrically with respect to the heating resistor and the orifice, so that the bending of the ink droplet in the ejection direction can be eliminated.

However, in these inkjet printer heads, the heating resistor and the flow path are located on the same plane, so the pressure generated on the surface of the heating resistor flows out of the flow path and is effectively transmitted to the orifice. Not done.

Therefore, as an inkjet printer head that solves the above-mentioned problems such as bending of the ejection direction of ink droplets and reduction in pressure transmission efficiency, the present applicant has proposed a patent application for patent application No. 1-29
There is a device proposed in No. 4240. Therefore, this inkjet printer head was used as the first technology as a prior art.
This will be explained based on FIGS. 1 to 16. The main structure of this inkjet printer head 1 is such that a substrate 2, a pressure chamber layer 3, a supply channel layer 4, and an orifice plate 5 are sequentially laminated, as illustrated in FIGS. 13 and 14. As illustrated in FIG. 11, the orifices 6 continuously formed in an array on the orifice plate 5 and the heating resistor 7, which is a pressure generating means formed on the surface of the substrate 2, are coaxially arranged. The pressure chamber layer 3 in which a rectangular annular partition wall 8 is formed with the heat generating resistor 7 at its center forms a pressure chamber 9 that is symmetrical with respect to the fine details of the orifice 6. The supply path layer 4, which is open at the portion facing the chamber 9, forms an ink supply path 10 that is open in the entire circumferential direction relative to the orifice 6. Furthermore, this inkjet printer head 1
Here, an ink storage chamber 11 is formed between the partition walls 8 of the pressure chamber layer 3, and an ink supply hole 12 communicating with the ink storage chamber 11 is formed in the substrate 2.

Next, the structure of each part of the inkjet printer head l having the above-described structure will be described in detail below along with the manufacturing method.

First, as illustrated in FIG. 15, the substrate 2 has a thickness of 0.
．． It is made of a Si wafer, etc., which has good heat dissipation of about 1 to 1.0 (m+), and has a thickness of 2.0 (μm) on the surface.
The heat storage layer 13 is formed of a certain amount of Sin, Al, O, or the like. Next, a Ta layer with a thickness of 0.4 (μm) is placed on top of this.
By sputtering AQ or TaN and patterning it by etching, the heating resistor 7 has a thickness of 0.4 (
Similarly, a resistance layer 14 with a thickness of 0.5 (μm) is formed.
) A common electrode 15 and individual electrodes 16 each made of Afi are formed. Next, on top of these, a first protective film 17 made of Si, N4 or Sio with a thickness of about 0.3 (μm) and a film made of Ta having good cavitation resistance and a thickness of about 0.2 (μm) are applied. CV [)
(Chemical Vapor Deposition
) method or sputtering.

The shape of the heating resistor 7 formed as described above is, for example, a square of 60 x 60 (μm). Furthermore, in the following description, the substrate 2 means the substrate on which the above-mentioned members 13 to 18 are formed.

Then, the pressure chamber layer 3 is formed on the substrate 2 on which the heating resistor 7 and the like are formed as described above. This pressure chamber layer 3 is shown in FIG. 16(a).

As illustrated in (b), photosensitive polyimide 19, which is one of the photosensitive resins with a thickness of 30 (μm), is coated on the substrate 2 and semi-cured (dried), and is photo-patterned. A partition wall 8 and an outer peripheral portion 20 are formed, and the pressure chamber 9 and the ink storage chamber 11 are provided.

Further, the ink supply hole 12 is formed in the substrate 2 through the ink storage chamber 11 by laser processing. for example,
The shape of the pressure chamber 9 formed as described above is 70 x 70 (μm) centered on the heating resistor 7.
The width of the partition wall 8 is 30 (μm).
It has become.

Here, the pressure chamber layer 3 formed on the substrate 2 as described above will be referred to as a first plate 21. The plate that is integrally joined to the second plate 22 will be referred to as the second plate 22.

Therefore, the structure of this second plate 22 will be explained below. First, as illustrated in FIG. 16(c), a mask 24 with a predetermined pattern is attached to a jig substrate 23 such as an SUS substrate, and Ni is electroformed to a thickness of 40 (μm). The orifice plate 5 is formed by utilizing the fact that the orifice 6 is raised around the mask 24 and has the orifice 6 whose tip end is narrower than the end end and whose minimum diameter is about 50 (μm). After this is peeled off from the jig substrate 23 and the mask 24 is removed, Au plating (not shown) to a thickness of 0.1 (μm) is performed to fix it onto the jig substrate 23 again. Therefore, as illustrated in FIG. 16(d), an uncured photosensitive polyimide 25 is placed on the orifice plate 5 to a thickness of 10 mm.
(μm), as illustrated in FIG. 16(e),
This is processed in the same manner as the pressure chamber layer 3 described above to form the ink supply path IO centered on the orifice 6. The second plate 22 is formed by removing the orifice plate 5, on which the supply path layer 4 is integrally formed, from the jig substrate 23 and cutting it into a predetermined shape.

Then, as illustrated in FIGS. 16(f) and (g), the first and second plates 21, 22 manufactured as described above are
Adhesive material (not shown) is attached to at least one outer peripheral portion 20 of the
The inkjet printer head 1 is manufactured by coating the orifice 6 and the heat generating resistor 7 with the same precision and pressing them together.

In such a configuration, the inkjet printer head 1 is equipped with a drive circuit (not shown) for each electrode 15,16.
is connected to the ink tank (
(both not shown) are connected and, as illustrated in FIG. 11, are arranged to face the printing paper 26 that moves relatively in the sub-scanning direction. Therefore, this inkjet printer head 1 is
When power is applied from each electrode 15.degree. 16 and the heating resistor 7 generates heat, the ink 27 in contact with it evaporates and bubbles 28 are generated. At this time, the propagation direction of the pressure change in the ink 27 due to the generation of the bubbles 28 is regulated by the pressure chamber 9 and directed toward the orifice 6. Therefore, the power supply from the electrodes 15, 16 is stopped in synchronization with the timing at which the ink 27 is ejected from the orifice 6, the temperature of the heating resistor 7 decreases, and the bubbles 28 contract. Then, due to the change in the pressure of the ink 27 due to the contraction of the air bubbles 28, a part of the ink 27 that has been bulging from the orifice 6 is cut off, and this becomes an ink droplet 27a and flies. Therefore, by selectively driving the heating resistor 7 to generate heat and causing the ink droplets 27a to fly from a predetermined orifice 6, an image can be formed on the surface of the printing paper 26 that moves relatively in the sub-scanning direction.

Note that each pressure chamber 9 is supplied with ink 27 which is sequentially replenished from the ink supply hole 12 from the ink storage chamber 11 via the ink supply path 10.

In this inkjet printer head 1, the shapes of the ink supply path 10 and the pressure chamber 9 and the position of the heating resistor 7 are symmetrical with respect to the axis of the orifice 6, so that pressure changes in these parts are symmetrical. The action direction and the feel direction are symmetrical, and the ink droplet 27a flies in the narrow direction of the orifice 6.

Furthermore, in this inkjet printer head 1, the heating resistor 7 on the substrate 2 is surrounded by the partition wall 8, and the orifice 6
, the pressure generated on the surface of the heating resistor 7 is transmitted to the orifice 6 without leaking to the side, resulting in good driving efficiency and labor saving of the equipment.

Problems to be Solved by the Invention In the above-mentioned inkjet printer head 1, since the arrangement of each part is symmetrical with respect to the axis of the orifice 6, the ejection direction of the ink droplets 27a is not bent. The pressure transmission efficiency is also good because it is surrounded by

However, the above-described inkjet printer head 1 has a structure in which the first plate 21 in which the pressure chambers 9 are minutely formed and the second plate 22 in which the orifices 6 are minutely formed are joined. Bonding requires extremely high precision, reducing productivity. Furthermore, the second plate 22 in which the orifices 6, which are fine through holes, are arranged in an array is not easy to manufacture as described above, and this is also a factor in reducing the productivity of the inkjet printer head 1.

Means for Solving the Problem A number of pressure chambers, each consisting of a pressure generating means and a partition wall, are linearly arranged on the surface of a first plate, and a pressure chamber of a second plate is joined to the first plate. A linear through groove is formed at a position facing the pressure chamber of the first plate, and the pressure applied by the pressure generating means to the ink in the pressure chamber of the first plate is deflected by the partition wall, and ink droplets are generated from the through groove of the second plate to each pressure chamber. was made to emit.

Function: Ink under pressure in the pressure chamber of the first plate is ejected as ink droplets from the through groove formed in the second plate, so unlike conventional devices, each pressure chamber has a fine through hole. Since it is not necessary to form an orifice, it is easy to manufacture the second plate, and it is also easy to align the slits in the second plate with the pressure chambers in the first plate.

Embodiment An embodiment of the present invention will be explained based on FIGS. 1 to 10. First, in the inkjet printer head 29 of this embodiment, as illustrated in FIGS. 1 to 3, a slit 31, which is a linear through groove, is formed in a second plate 30 that does not have a supply path layer. For example, the partition wall 33 of the pressure chamber 9 of the first plate 32 facing the slit 31 is formed to have a lower height than the outer peripheral portion 20. In a state where these first and second plates 32 and 30 are integrally joined, there is a gap in the entire circumferential direction between the leading edge of the partition wall 33 of the pressure chamber 9 and the back surface of the second plate 30. A gap is formed that is open to the ink storage chamber 11 and the pressure chamber 9, and this serves as an ink supply path 34 that communicates the ink storage chamber 11 and the pressure chamber 9.

Here, the partition wall 33 of the pressure chamber 9 of the first plate 32
is formed to a height of about 20 to 30 (μm), which is higher than at least the maximum height 172 of the bubbles 28 generated on the surface of the heating resistor 7, so that the pressure deflection is improved. Then, a second plate 30 is formed with a slit 31 having a width of about 30 to 50 (μm), which is the same as that of the pressure chamber 9.
is manufactured from Ni electroformed parts, pressed parts, molded parts, etched parts, etc.

In such a configuration, this inkjet printer head 29, like the above-mentioned inkjet printer head 1, transfers the pressure generated on the surface of the heating resistor 7 to the pressure chamber 9.
The ink droplet 27a is deflected by the partition wall 33 and flows from the slit 31.
stand out.

Second, this inkjet printer head 29 has a slit 31, which is a linear through-groove, that faces the linearly continuous pressure chamber 9 and ejects the ink droplet 27a. Therefore, this inkjet printer head 29 is
Unlike the conventional inkjet printer head l, it is not necessary to form the orifice 6, which is a fine through hole, in each pressure chamber 9, so the production of the second plate 30 is easy; Since positional alignment between the slits 31 of the first plate 30 and the pressure chambers 9 of the first plate 32 is relatively easy, the productivity is extremely high. Furthermore, in this inkjet printer head 29, as illustrated in FIG. 4, by making the partition wall 33 of the pressure chamber 9 lower than the outer peripheral part 20 of the pressure chamber layer 3, ink can be stored without forming a supply path layer. An ink supply path 34 communicating from the chamber 11 to the pressure chamber 9 is formed to further contribute to improving the productivity of the apparatus.

Moreover, the inkjet printer head 29 of this embodiment
Now, as illustrated in FIG. 5, the productivity of the first plate 32 is also improved by omitting the patterning of the resistance layer 14 and forming the heating resistor 7 in the pattern of the electrodes 15 and 16. There is.

Here, an example of a practical method for manufacturing the first plate 32 as described above will be described in detail below. First, the thickness is about 0.5 (
The surface of the Si substrate 2 (mn) is thermally oxidized to a thickness of approximately 1.5 mm.
A heat storage layer 13 made of Sin (μm) is formed, and a resistive layer 14 is uniformly formed on this by sputtering Ta5iO to a thickness of about 3000 (A).
On top of this, a film was formed by sputtering to a thickness of approximately 5000 mm (
Each of the electrodes 15 and 16 is formed by patterning the AQ film of AQ film by photolithography. Then, a highly insulating first protective film 17 made of Sin or 5iUx with a thickness of approximately 4000 μm is formed on these by CVD or sputtering, and then sputtering or vapor deposition is applied on top of this. Then, a second protective film 18 made of Ta, Ti, Cr, or the like having high cavitation resistance and having a thickness of about 1000 μm is formed.

In addition, in the above-mentioned embodiment, the pressure chamber 9 of the first plate 32
By separating the leading edge of the partition wall 33 and the back surface of the second plate 30 to form an ink supply path 34, the pressure chamber 9
Although the inkjet printer head 29 is shown as an example, the present invention is not limited to the above structure. Since the chamber 11 and the pressure chamber 9 are communicated with each other, for example, the partition wall 33 of the pressure chamber 9
It is also possible to implement an inkjet printer head (not shown) having a structure in which the leading edge of the second plate 30 contacts the back surface of the second plate 30 and the ink supply path 34 does not exist.

Moreover, in the above-mentioned inkjet printer head 29,
Although the second plate 30 is exemplified with slits 31 having the same width on the upper and lower sides, the present invention is not limited to the above structure, and as illustrated in FIG. It is also possible to implement inkjet printer heads 37 to 39 in which a slit 36 is formed, which is a through hole narrow at the top and wide at the bottom. Here, when the slit 36 having such a shape is formed, the partition wall 33 of the pressure chamber 9 is connected to the second plate 3, as illustrated in FIG.
Since the ink supply path 34 is formed even if the ink supply path 34 is not separated from the back surface of the pressure chamber 9, the partition wall 33 of the pressure chamber 9 and the back surface of the second plate 30 are on the same plane, as illustrated in FIG. 6(b). The inkjet printer head 38 located at
As illustrated in FIG. 3C, an inkjet printer head 39 in which the upper edge of the partition wall 33 of the pressure chamber 9 is located within the slit 36 of the second plate 30 can also be implemented. In this case, in the inkjet printer head 38 illustrated in FIG. 6(b), the partition wall 33 of the pressure chamber 9 and the outer circumference 2
0 can be formed at the same height, which contributes to improving the productivity of the apparatus. In the inkjet printer head 39 illustrated in FIG. It can improve efficiency and contribute to higher performance of the device. The slit 36, which is wider at the bottom than at the top, is formed to have an upper width of about 50 (μm) and a lower width of about 150 (μm), for example, and its shape is similar to that shown in the figure. In addition to those with straight portions, those with curved side portions, and combinations thereof are also possible.

Further, in the above-described inkjet printer head 29, it is assumed that the partition wall 33 of the pressure chamber 9 is formed in a square cylindrical shape, as illustrated in FIG. 7, but the present invention is not limited to the above structure. It is sufficient that the shape of the pressure chamber 9 is symmetrical with respect to the axis of the slit 31. Therefore, as illustrated in FIGS. 8 and 9, the partition wall 4 may be cylindrical or polygonal.
0, 41, etc. are also possible.

Moreover, in the above-mentioned inkjet printer head 29,
As illustrated in No. 10rIfJ(a), the heating resistor 7 is surrounded by the partition wall 33 of the pressure chamber 9, but the present invention is not limited to the above structure, and the heating resistor 7 is surrounded by the partition wall 33 of the pressure chamber 9.
The heating resistor 7 functions as long as most of it is located within the partition wall 33 of the pressure chamber 9, so as illustrated in FIG.
It is also possible to form the partition wall 33 of the pressure chamber 9 on the surface of the pressure chamber 9 .

Further, in the above-mentioned inkjet printer head 29, etc., a bubble jet method using the heating resistor 7 as a pressure generating means was exemplified, but the present invention is not limited to the above method, and the present invention is not limited to the above method. It is also applicable to a piezo system using a strain element.

Effects of the Invention As described above, the present invention includes a plurality of pressure chambers each consisting of a pressure generating means and a partition wall arranged linearly on the surface of a first plate, and a second pressure chamber joined to the first plate. A linear through groove is formed at a position facing the pressure chamber of the first plate, and the pressure applied to the ink in the pressure chamber of the first plate by the pressure generating means is deflected by the partition wall to generate pressure from the through groove of the second plate. By ejecting ink droplets from each chamber, a linear through groove is used to eject ink droplets facing a linearly continuous pressure chamber, and unlike conventional devices, each pressure chamber is Since it is not necessary to form an orifice, which is a through hole, the second plate is easy to manufacture, and
Since the positional alignment between the slits of the second plate and the pressure chambers of the first plate is easy, it is possible to contribute to improving the productivity of the inkjet printer head.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing an embodiment of the present invention, Fig. 2 is a perspective view, Fig. 3 is an exploded plan view of each part, Fig. 4 is a longitudinal side view, and Fig. 5 is a longitudinal side view of main parts. Fig. 6 is a vertical side view showing the first, second, and third modifications, Fig. 7 (a) is a plan view of the main part, Fig. 7 (b) is a side view, and Fig. 8 (a) 8(b) is a side view, FIG. 9(b) is a side view, and FIG.
Figure (a) is a plan view of the main part showing the fourth modification, and Figure 9 (
b) is a side view, Fig. 10(a) is a plan view of the main part, Fig. 10
Figure (b) is a plan view showing the fifth modification, Figure 11 is a longitudinal cross-sectional side view of an inkjet printer head showing the prior art disclosed in Japanese Patent Application No. 1-294240, and Figure 12 is an exploded view of each part. FIG. 13 is a plan view, FIG. 13 is an exploded perspective view, FIG. 14 is a perspective view, FIG. 15 is a vertical sectional side view of main parts, and FIG. 16 is a manufacturing process diagram. 7...Pressure generating means, 9...Pressure chamber, 29.37~
39... Inkjet printer head, 30, 35
...Second plate, 31.36...Through groove, 32
...First plate, 33, 40. 41... Bulkhead wall, Figure 3 (a) (b) Figure 35'' Figure 7 JC Figure 3q Figure 10 (a) U JZ Figure (a) (b' ) vinegar

Claims (1)

[Claims] A first plate having a plurality of pressure chambers linearly arranged on its surface, each consisting of a pressure generating means and a partition wall, and a linear through groove formed at a position facing the continuous pressure chambers. a second plate joined to the second plate, and the pressure applied to the ink in the pressure chamber of the first plate by the pressure generating means is deflected by the partition wall to cause the ink to flow from the through groove of the second plate to the second plate. An inkjet printer head characterized by ejecting ink droplets from each pressure chamber.