JPH0242355B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a method of ejecting ink liquid from minute openings,
The present invention relates to a method of manufacturing nozzles for ink jet heads for recording characters, figures, images, etc. on recorded materials.

2. Description of the Prior Art Structure and Problems In recent years, inkjet recording devices have come to be used as terminal equipment for color printers and computers.

FIG. 1 shows a sectional view of an ink nozzle disclosed in Japanese Unexamined Patent Publication No. 57-131569. 1 is an ink nozzle plate, 2 is a nozzle end, and 3 is an ink discharge port.
As shown in FIG. 1, if the nozzle end 2 is configured with a ring-shaped convex portion, the nozzle end 2 has a constant shape and has a sharp edge, so that ink droplets are ejected. After wetting the nozzle end 2, there is less remaining ink liquid due to wetting, and the lateral directing force of the attractive force due to surface tension becomes extremely small, and all the lateral directing forces are equal, so the ink liquid It is known that there is an effect that droplets are ejected in the axial direction of the ink ejection opening 3.

Although it is unclear how an ink nozzle with this configuration is manufactured as it is not disclosed in the above publication, it is possible to manufacture it using a photosensitive resin with a structure similar to that shown in Figure 1. A method shown in FIG. 2 is known.

In FIG. 2A, the exposure mask 17 is placed over the photosensitive resin 16 and exposed. There is a mask pattern 18 corresponding to the ink ejection opening 20 and a mesh mask pattern 19 around it, and since the pattern 18 does not transmit light, the photosensitive resin 16 in the area covered by the pattern 18 is not exposed. Furthermore, the area of the photosensitive resin 16 covered by the mesh pattern 19 is not completely masked and is therefore slightly exposed. Further, the periphery of the pattern 18 is exposed in an annular manner.
The exposed portion of the photosensitive resin 16 undergoes a polymerization reaction, hardens, and becomes insoluble in solvents.

When the image is developed with a solvent after exposure in the state shown in FIG. 2a, the portion covered by the mask 18 is dissolved by the solvent, and the ink discharge ports 20 are perforated as shown in FIG. 2b. The portion covered with the mesh mask pattern 19 has lower solubility in the solvent, and the second
As shown in FIG. b, the photosensitive resin 16 is dissolved up to the middle of its thickness during the development process that takes the time required to drill the ink discharge ports 20. On the other hand, mask 18
The ring-shaped portion around the ink discharge port 20 is sufficiently exposed and is insoluble in the solvent, so that a convex portion is formed around the ink discharge port 20 as shown in FIG. 2b. Finally, from the surface opposite to the surface on which the convex portion of the ink discharge port 20 is formed, the ink discharge port 2 is
By cutting the shape of 0 into a conical shape, a head nozzle having the structure as shown in FIG. 1 can be obtained by using photosensitive resin. After the development process is completed, the photosensitive resin is cured by heating or ultraviolet irradiation.

However, although the above method has good dimensional accuracy such as the diameter D ₂ of the ink discharge port 20 and the diameter D ₃ of the end surface of the convex portion, the shape of the ink discharge port 20 is
Since it is tapered and cannot have a shape with a counterbore, it is difficult to reduce the internal resistance of the ink discharge port 20. As a result, the injection energy increases, which has become a problem. Also, photosensitive resin 1
Since No. 6 is an organic substance, it may swell with ink, especially oil-based ink, and because it lacks rigidity, it may deform if it has a minute shape such as the size of ΔB in Figure 4b of 20 μm. It was hot.

Figure 3 shows the manufacturing process of forming an ink nozzle with a ring-shaped convex part using a nozzle plate with a two-layer structure in which a metal layer is formed on an insulating substrate. Indicates how the application was filed. Third
Figure a shows a nozzle plate with a two-layer structure in which a copper layer 13 is bonded to one side of an insulating substrate 12. Figure 3b
After masking the nozzle plate of FIG. 3A with resist, 13 portions of the copper layer are chemically etched to form convex portions. Fig. 3c shows that the convex portion of the copper layer 13 is micro-drilled.
This is where the ink ejection ports 14 are drilled.

Although this method is good for forming one nozzle, there are various problems when forming a multi-nozzle in which two or more nozzles are lined up. In other words, since side etching is large when processing with chemical etching, the diameter dimension D ₁ of the end surface of the convex portion
There may be variations in the shape of the end face, and the shape of the end face may not be a perfect circle. Furthermore, when the ink discharge port 14 is processed with a micro drill, an eccentricity ΔA occurs with respect to the end surface of the convex portion, and a burr 15 occurs. Therefore, with the manufacturing method shown in Figure 3, it is difficult to improve the dimensional accuracy between each nozzle, and for this reason, in the case of multi-nozzles in which two or more are arranged, the recording characteristics of each nozzle may vary. It was becoming a problem that they were not aligned.

OBJECT OF THE INVENTION The present invention aims to eliminate the above-mentioned drawbacks, and provides an inkjet recording head that is rigid, has a strong specific resistance, has excellent ink resistance, has good dimensional accuracy, and is easily machined. The purpose is to provide a nozzle manufacturing method.

Structure of the Invention In order to achieve the above object, the present invention includes a first step of exposing a photosensitive glass plate except for a ring-shaped pattern around a position where a nozzle hole is to be formed;
a second step of heat-processing and developing the exposed photosensitive glass plate; a third step of half-etching both sides of the photosensitive glass plate to form ring-shaped convex portions on both sides; and the half-etching. A fourth step of masking one side of the etched surface with an etching-resistant material, and using the ring-shaped convex portion on the opposite side of the surface masked in the fourth step as a barrier, A fifth step of masking by spreading the liquid etching-resistant material around the ring-shaped convex portion without putting the liquid etching-resistant material into the convex portion of the ring.
a sixth step of changing the liquid etching-resistant liquid material masked in the fifth step into a solid state; and a step of changing the ring-shaped convex portion from the direction masked in the fifth step A seventh step of forming a through hole in the photosensitive glass plate by etching the inside of the photosensitive glass plate.
The nozzle of the inkjet recording head is manufactured by the process described in the following.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, FIG. 4 shows an example of a suitable ink jet recording apparatus using an ink nozzle plate manufactured according to the present invention. In FIG. 4, an insulating nozzle plate 4 has an air outlet 5 perforated therein, a nozzle plate 6 is disposed parallel to this nozzle plate 4, and a nozzle plate 6 is arranged opposite to the air outlet 5. An ink discharge port 7 is perforated therein. The ink discharge port 7 is provided with a convex portion extending in the direction of the air discharge port 5. An air flow is sent from the periphery to the air layer 8 formed by the nozzle plate 4 and the nozzle plate 6, and is caused to flow out from the air outlet 5 to form a rapid change in pressure gradient due to the bending of the air flow. The signal source 9 is the nozzle plate 4
a conductive ink supply pipe communicating with the electrode 10 and the ink discharge port 7 such that a potential difference is generated between the electrode 10 provided on the surface of the air discharge port 5 and the ink within the ink discharge port 7; 11. Ink droplets are ejected by airflow and electrostatic forces. As shown in FIG. 4, if the ink discharge port 7 is provided with a convex portion extending in the direction of the air discharge port 5, the air flow is bent more sharply due to the influence of the protruding ink discharge port 7. A dead area of the air flow occurs near the ink ejection port 7, and there is almost no pressure gradient of the air flow in this dead area.
Therefore, even if the ink mechanics at the ink ejection port 7 slightly fluctuates, the ink will not be ejected, and the stability of the ink mechanics will increase.

FIG. 5 shows a manufacturing process of an ink nozzle in which ink discharge ports 7 are formed on the nozzle plate 6 shown in FIG. In FIG. 5a, 21 is a photosensitive glass, for example SiO ₂ −Al ₂ O ₃ − containing CeO ₂ and Ag ₂ O.
It is Li ₂ O glass, and an exposure mask 22 is placed on top of it.
is placed and exposed to ultraviolet light with a wavelength of 280 to 350 nm. In the exposure mask 22, the ring-shaped portion 22a blocks light, and the ring-shaped portion 22b transmits light. Fig. 5b shows the state after irradiation with the light in Fig. 5a. In the area 21b where the light hits, a reaction of Ce ³⁺ +Ag ⁺ + ultraviolet light → Ce ⁴⁺ +Ag ⁰ occurs, and this is followed by the first reaction. Heat treated,
A metal colloid of Ag is generated, and through a second heat treatment, this metal colloid becomes a nucleus.
Li ₂ O−SiO ₂ crystals are generated. _Li2O - _SiO2 crystals obtained by such heat treatment and development are extremely easy to dissolve in acids. Therefore, the part 2 that was hit by the light
1b can be easily etched with an aqueous hydrofluoric acid solution. The portion 21a that is not exposed to light is not crystallized and is not easily corroded by the hydrofluoric acid aqueous solution. Next, in FIG. 5c, both sides of the photosensitive glass 21 are half-etched to a predetermined depth using a hydrofluoric acid aqueous solution. For example, half-etching the crystallized portion 21b to a depth of 30 μm can be carried out in about 5 minutes by immersion etching in a hydrofluoric acid aqueous solution with a hydrofluoric acid concentration of 5% at a solution temperature of 20°C. The etching rate ratio of the crystallized portion 21b and the non-crystallized portion 21a of the photosensitive glass 21 is approximately 30:
1, the crystallized portion 21b is etched faster, so the portions indicated by 23 and 24 in the figure are etched faster, resulting in approximately the same ring-shaped convex portions 25 on both sides. and 26 are formed. Since the non-crystallized portion 21a is also slightly etched, the ring-shaped convex portions 25 and 26 become tapered. Next, as shown in FIG. 5d, one entire surface of the photosensitive glass 21 is masked with an etching solution-resistant material such as a hydrofluoric acid-resistant material such as paraffin-based Electron Wax (manufactured by Sodenshi Kogyo Co., Ltd.) 28. Electron wax 28 is a paraffin-based adhesive that forms a liquid phase and a solid phase depending on the temperature.Since it becomes liquid at temperatures above about 48°C, the electron wax 28 is heated to 58°C for example. Apply 28 and mask it,
A glass substrate 29 is attached to the electron wax 28 for ease of handling. and,
The surface opposite to the surface masked with electron wax 28 is masked with electron wax 27 made of the same material as above. If the temperature of the photosensitive glass 21 is raised to, for example, 58° C., the amount of electron wax 27 applied is adjusted to the area to be applied, and the temperature is maintained for a predetermined period of time, the electron wax applied near the ring-shaped convex portion 26 will be removed. 27 gradually gets wet and spreads, and masking can be performed without the electron wax 27 entering into the ring-shaped convex portion 26. Here, Electron Wax 2
The film thickness of No. 7 is 5 μm or more. Hydrofluoric acid concentration 5%
When etching is performed by immersion etching in a hydrofluoric acid aqueous solution at a temperature of 20° C. for about 5 minutes, the half-etched surface 24 of the crystallized portion 21b is etched.
a shows an end surface 26a and a side surface 26b of a half-etched ring-shaped convex portion 26 of a non-crystallized portion 21a with a center line average roughness of 0.1 μm.
The average roughness of the center line is 0.01 .mu.m and 0.05 .mu.m, and the end surface 26a has a smaller surface roughness than the other surfaces, so the wettability of the electron wax 27 is poor.
Therefore, since the end surface 26a has poor wettability, it is possible to hold the electron wax 27 at the peripheral edge 26c of the ring-shaped convex portion 26. Further, since the ring-shaped convex portion 26 is raised in a convex shape, the electron wax 27 can be stored therein, so that the electron wax 27 can be applied thickly. For these reasons, the ring-shaped convex portion 26 is made of electron wax 27.
However, if the size is too small, it will prevent the electron wax 27 from entering the ring-shaped convex part 26.
It will be difficult to hold it in place, so it is necessary to set it to an appropriate size. Here, in the figure ΔC
= 30 μm, ΔD = 20 μm. Next, the temperature of the electron wax 27 is lowered to change it from a liquid state to a solid state. Furthermore, in FIG. 5e, the photosensitive glass 21 is etched a second time from the ring-shaped convex part 26 to the ring-shaped convex part 25 on the opposite side from the side masked with the electron wax 27. Continue until the hole goes through. Electron wax 27 begins to soften at a temperature of about 34°C, so it is better to etch it with a hydrofluoric acid aqueous solution at a temperature lower than 34°C, and since it has low mechanical strength, it is better to use a dipping method as the etching method. For example, if the second etching depth is 170μm,
When the hole diameter is about 50 μm, it can be made in 35 minutes using a hydrofluoric acid aqueous solution with a hydrofluoric acid concentration of 5%, a solution temperature of 20° C., and the immersion method. The etched portion 30 is a penetrating portion where a large amount of the crystallized portion 21b of the photosensitive glass 21 is etched, and the non-crystallized portion 21a.
It is also slightly etched and tapered. The etched portion 31 is a side etched portion that is generated due to slight dissolution of the electron wax 27 by the hydrofluoric acid aqueous solution and etching of the non-crystallized portion 21a, and is a side etched portion that is generated due to the etching of the non-crystallized portion 21a.
The sides are also slightly etched. Next, as shown in FIG.
By peeling off the electron waxes 27 and 28 and removing the glass substrate 29 at the same time, a nozzle having a ring-shaped convex portion 25 as shown in the figure could be formed. If the opposite surface of the ring-shaped convex portion 25 is uneven and causes any inconvenience, it is advisable to polish it as shown in FIG. 5g to make it flat as shown. In addition, if you want to further improve the rigidity, acid resistance, heat resistance, etc. of the photosensitive glass 21, the entire surface is exposed to ultraviolet rays again and subjected to a tertiary heat treatment to reduce Li ₂ O・2SiO ₂
It is good to generate crystals.

FIG. 6 is a sectional view of a nozzle formed by the above manufacturing method. The ink discharge port consists of an etched portion 23a and an etched portion 30a. In the first etching, the ring-shaped convex part 2
5a and the etched portion 23a of the ink discharge port are ΔE.
By the second etching, the etched portion 30a of the ink discharge port is formed at a depth of ΔF. In the second etching, etching part 2
Place electron wax in the hole 3a, mask it, and then perform etching. From the point where it penetrates, slightly overetch the etched portion 30a to increase the hole diameter of the etched portion 30a, and create an ink discharge port with a counterbore as shown in the figure. can be formed, so
According to this embodiment, an ink ejection port with low internal resistance can be formed. According to this embodiment,
The nozzle is formed by etching twice, but since the first etching time is short and there is little side etching, it is easy to achieve dimensional accuracy, and masking is performed after the first etching to cover the first etching surface. Since the second etching is performed after protection, the variations in the diameters D ₄ and D ₅ of the ink ejection ports and the diameter D ₆ of the peripheral edge 26 c of the ring-shaped convex portion 25 a are particularly important dimensions. Accuracy can be kept within ±2 μm. This also applies to a multi-nozzle structure in which a plurality of nozzles are lined up. The specific dimensions of the invention are:
D ₄ = 45μm, D ₅ = 50μm, D ₆ = 90μm, ΔE = 30μm
m, ΔF=170 μm. According to this example, by using a ring-shaped convex part, a hydrofluoric acid aqueous solution with a hydrofluoric acid concentration of 5%, a liquid temperature of 25°C, and a immersion method can be used.
Electron wax, a hydrofluoric acid-resistant material, can be masked to a thickness of 5 μm or more so that it can withstand etching for more than 50 minutes, and it can also mask high-density patterns such as 4 nozzles per mm. Therefore, high-density nozzles can be formed with high precision. and,
Although the dimension of ΔG is small at 20 μm, the photosensitive glass is rigid, so a nozzle that does not deform can be created. Photosensitive glass has excellent ink resistance and no risk of swelling, and has a high specific resistance and is an insulator, so this nozzle plate can be used in the inkjet recording head that uses air flow and electrostatic force as explained above. In this case, good ejection characteristics were obtained because the electrostatic force was concentrated on the ink. Furthermore, the ring-shaped pattern of the exposure mask is directly transferred to the photosensitive glass plate by exposure and development, and the photosensitive glass itself to be etched is color-coded into areas that are easy to etch and areas that are difficult to etch. A nozzle plate with good concentricity between the outlet and the peripheral edge of the ring-shaped convex portion and good straightness of the ink ejection port was manufactured.

FIG. 7 is a sectional view for explaining a method of manufacturing a nozzle in another embodiment of the present invention. 7th
In FIG. a, substantially the same ring-shaped convex portions 34 and 37 are formed on both sides of the photosensitive glass 32 by the same steps as steps a to c of the embodiment shown in FIG. 3
2a is a non-crystallized portion, and 32b is a crystallized portion. One side of the photosensitive glass 32 is masked with an etching liquid-resistant material, such as Epicoat (an epoxy resin adhesive manufactured by Ciel Chemical Co., Ltd.) 33, which is a hydrofluoric acid-resistant material. Here, Epikote 828 is used as the main ingredient, which is liquid at room temperature, and Epicure Z is used as the curing agent. If the temperature of the photosensitive glass 32 is raised to, for example, 40°C, the amount of Epicoat 33 to be applied is adjusted to the area to be applied, and maintained for a predetermined period of time, the ring-shaped convex portion 34 is formed for the same reason as the embodiment shown in FIG. Masking can be performed without the Epicoat 33 entering inside. Here, the thickness of the epicoat 33 is set to 5 μm or more. next,
After temporarily curing Epicoat 33 at room temperature for 50 hours,
Mainly cure for 60 minutes at a temperature of 70℃. If this temporary curing is removed, the Epicoat 33 will become less viscous and will enter the ring-shaped convex portion 34 when the temperature is raised, so care must be taken. Then, the temperature of the photosensitive glass 32 is raised to 58°C, and the entire surface opposite to that masked with Epikote 33 is masked with Electron Wax 35, which is an etching liquid-resistant material. A glass substrate 36 is attached to 35. Next, in FIG. 7b, the second etching of the photosensitive glass 32 is performed from the ring-shaped convex portion 34 from the side masked with the Epicoat 33.
This is done until the hole passes through the ring-shaped convex portion 37 on the opposite side. The etched portion 38 is a penetrating portion. The etched portion 39 is a side etched portion produced by etching the non-crystallized portion 32a, and the etched portion 39 is a side etched portion resulting from etching of the non-crystallized portion 32a.
It is also slightly etched. Next, in FIG. 7c, after etching with the aforementioned hydrofluoric acid aqueous solution, the electron wax 35 is peeled off by washing with water and ultrasonic cleaning with trichlorethylene, and the glass substrate 36 is also removed at the same time. Thereafter, the Epicoat 33 was peeled off by oxygen plasma ashing, and a nozzle having a ring-shaped convex portion 37 as shown in the figure could be formed. FIG. 7d shows the state in which the other surface of the photosensitive glass 32 has been polished and made flat. Further, the photosensitive glass 32 is subjected to a tertiary heat treatment by being exposed to ultraviolet rays.

According to this embodiment, compared to the electron wax of the embodiment shown in FIG. 5, the epicoat 33 has better adhesion to the photosensitive glass 32 and has greater mechanical strength, so the size of the etched portion 39 is reduced. Furthermore, the etching method using a hydrofluoric acid aqueous solution can be performed not only by dipping but also by spraying. In this example, the masking material is
Although Epicoat 33 and Electron Wax 35 are used, if Epicoat is used instead of Electron Wax 35, the temperature of the hydrofluoric acid aqueous solution during etching can be increased and the etching rate can be increased.

In the above description, the masking material is Electron Wax and Epicoat. However, the masking material may be other paraffin, other adhesive, resist, or the like. Further, the shape of the convex portion is not limited to a circle, and may be formed in any shape such as a square or a triangle. Furthermore, both sides of the photosensitive glass may be half-etched separately so that the ring-shaped convex portions have different sizes.

Effects of the Invention As described above, the present invention includes a first step of exposing a photosensitive glass plate except for a ring-shaped pattern around a position where a nozzle hole is to be formed, and the exposed photosensitive glass plate. a second step of heat treatment and development; a third step of half-etching both sides of the photosensitive glass plate to form ring-shaped convex portions on both sides; and etching the half-etched one side with etching solution resistance. A fourth step of masking with a material, and using the ring-shaped convex portion on the opposite side of the surface masked in the fourth step as a barrier, injects liquid into the ring-shaped convex portion. a fifth step of masking by spreading the liquid etching-resistant material around the ring-shaped convex portion without putting in the etching-resistant material; and masking in the fifth step. a sixth step of changing the etching-resistant liquid material into a solid state; and a fifth step of etching the inside of the ring-shaped convex portion from the direction masked in the fifth step to form the photosensitive glass. By the seventh step of forming through holes in the plate, a nozzle having a ring-shaped convex portion of the inkjet recording head is formed, and the following effects can be obtained.

(1) The dimensional accuracy of the nozzle is improved, and the ink ejection amount, ink ejection direction, and recording characteristics can be made uniform.

(2) The ink ejection port has a counterbore shape and the resistance inside the tube is reduced, so the driving voltage at the ink jet head can be lowered.

(3) The hydrofluoric acid-resistant material can be masked to a thickness of 5 μm or more to withstand etching using a hydrofluoric acid aqueous solution with a hydrofluoric acid concentration of 5% at 25°C for more than 30 minutes, and the nozzle hole can be Precision etching processing is possible.

(4) High-density, high-precision multi-nozzles can be formed.

(5) Photosensitive glass that is rigid, has high specific resistance, and has excellent ink resistance can be easily processed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a nozzle part of a conventional inkjet recording head, FIG. 2 is a process diagram for explaining a conventional ink nozzle manufacturing method, and FIG. 3 is a diagram related to an earlier application filed by the present applicant. FIG. 4 is a sectional view showing an example of an inkjet recording device to which the present invention is applied; FIG. 5 is a process diagram showing an embodiment of the nozzle manufacturing method according to the present invention. 6 is an enlarged sectional view of an inkjet recording head nozzle obtained according to the present invention, and FIG. 7 is a process diagram showing another embodiment of the nozzle manufacturing method according to the present invention. 21, 32...Photosensitive glass, 22...Exposure mask, 23a, 30a...Etching portion, 25,
25a, 26, 34, 37... Convex portion, 27, 2
8, 33, 35...Etching liquid resistant material, 2
9,36...Glass substrate.

Claims (1)

[Claims] 1. A first step of exposing the photosensitive glass plate except for the ring-shaped pattern around the position where the nozzle hole is to be formed, and heat-processing and developing the exposed photosensitive glass plate. a second step, a third step of half-etching both sides of the photosensitive glass plate to form ring-shaped convex portions on both sides, and masking the half-etched one side with an etching liquid-resistant material. a fourth step, using the ring-shaped convex portion on the opposite side of the surface masked in the fourth step as a barrier, and applying a liquid anti-etching inside the ring-shaped convex portion; a fifth step of masking by spreading the liquid etching-resistant liquid material around the ring-shaped convex portion without introducing a liquid material; and the liquid masked in the fifth step. a sixth step of changing the etching-resistant liquid material into a solid state, and a fifth step of etching the inside of the ring-shaped convex portion from the direction masked in the fifth step to form a through hole in the photosensitive glass plate. 1. A method for manufacturing an inkjet recording head nozzle, comprising a seventh step of forming a nozzle. 2. Manufacturing a nozzle for an inkjet recording head according to claim 1, wherein in the fifth step, the etching liquid-resistant material is paraffin that undergoes a phase change between a liquid phase and a solid phase depending on the temperature. Method. 3. The method of manufacturing an inkjet recording head nozzle according to claim 1, wherein in the fifth step, the etching liquid-resistant material is an adhesive that solidifies through a chemical reaction.