JP3077444B2 - Ink jet head and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head used in an apparatus such as a printer for ejecting ink droplets to form an ink image on a medium such as recording paper.

[0002]

2. Description of the Related Art In general, an ink jet head applied to an ink jet recording method (liquid jet recording method) has a fine ink discharge port (hereinafter referred to as an orifice), an ink supply port, an ink flow path, and a part of an ink flow path. Energy working chamber) or an energy generating element that is provided outside the substrate and generates energy used for discharging ink. At the time of recording, the operation of the energy generating element causes small droplets of ink from the orifice. The ink is ejected and lands on the recording paper, whereby printing and recording are performed. Such an ink jet head is disclosed in Japanese Patent Publication No. 2-42670. The structure will be described with reference to FIGS. FIG. 11 is a schematic perspective view of the inkjet head. FIG. 13 is a cross-sectional view when cut at the position indicated by the one-dot chain line YY ′ in FIG. This will be described with reference to FIG. The substrate 1 is made of glass, plastic, ceramic, metal, or the like, and functions as one of the wall surfaces of the ink flow channel groove 9, the ink supply port groove 10, and the energy action chamber groove 11. In the manufacturing method, first, an energy generating element 2 for generating energy used for discharging ink from an orifice 7 is disposed on a substrate 1.

Next, a photosensitive resin layer 4 is formed on the substrate 1 on which the energy generating elements 2 are provided. Next, an ink flow path groove 9, an ink supply port groove 10, and an energy action chamber groove 11 are collectively formed in the photosensitive resin layer 4 cured by a known photolithography means. Finally, an ink jet head is obtained by covering each groove with a cover plate 8 (hereinafter referred to as an orifice plate) on which the orifice 7 is formed.

In recent years, an ink jet head having a high arrangement density of the orifices 7 has been required to obtain high-definition printed matter. In that case, since the interval between the energy action chambers 11 becomes narrow, the width of the energy action chamber 11 also becomes small. Therefore, it is important to increase the height of the energy action chamber 11 in order to obtain a required pressure volume.
If the pressure volume is insufficient, the amount of ink at the time of ink discharge becomes small, and the area per recording dot on the recording medium becomes small. However, there are also problems such as a decrease in printing speed, an unstable supply of ink to the energy action chamber 11, and an unstable ink discharge characteristic. If the photosensitive resin layer 4 is made thicker, the energy action chamber 11 can be made higher. However, if the thickness becomes thicker, light does not uniformly reach from the top surface to the bottom face of the photosensitive resin layer 4 at the time of exposure, so that the dimensional accuracy of the energy action chamber 11 deteriorates, and The ejection characteristics become unstable. Therefore, in order to raise the energy action chamber 11 with high precision, the energy action chamber groove 11, the ink flow path groove 9, and the ink supply port groove 10 are formed not only on the substrate 1 but also on the orifice plate 8 with the photosensitive resin layer 4. A method has been proposed in which the height of the energy action chamber 11 is increased by bonding to the grooves on the substrate side. At this time, it is necessary to join them so that there is no displacement. In order to reduce the positional deviation, first, the ink flow path groove 9, the energy action chamber groove 11, the ink supply port groove 10 of the photosensitive resin layer 4 are formed.
It is necessary to precisely dispose at a predetermined position on the substrate 1 and the orifice plate 8. As a method for this, an exposure mask alignment reference hole 3 is provided in the substrate 1 and the orifice plate 8, and the substrate 1 and the orifice plate 8 are aligned with each other while observing the positional deviation between the reference hole 3 and the center of the exposure mask alignment mark 6 with an optical microscope or the like. It is common to finely move the orifice plate 8 back and forth and left and right to make it match. Specifically, as shown in FIG. 10, since the exposure mask alignment mark 6 has a shape including an arc slightly larger than the reference hole diameter and an arc slightly smaller than the reference hole diameter, the reference hole 3 is inserted between the two arcs. Perform positioning. Next, the substrate 1 and the orifice plate 8 need to be overlapped and joined with high precision in order to reduce the displacement.

[0005]

However, as shown in FIG. 11, an exposure mask alignment reference hole 3a at the time of exposure and a positioning alignment reference hole 3b at the time of bonding are separately provided.
Even if each groove is accurately positioned at a predetermined position with respect to the reference hole 3a at the time of exposure, even if the exposure mask alignment reference hole 3a of the substrate 1 and the orifice plate 8 used at the time of exposure is aligned with the alignment reference hole 3a used at the time of bonding. The variation between the distances to the distance 3b is added at the time of joining, and the positional deviation increases (see FIG. 12). For this reason, there arises a problem that the ink flow path resistance increases and the ink ejection speed decreases.
In the future, since the arrangement density of the orifices 7 will be further increased, the width of the ink flow path will be narrowed, and the positional deviation in this direction will have a great effect on the ink ejection characteristics. In addition, there is another problem that bubbles are hard to be removed and ink is not discharged.

In addition, when the height of the energy action chamber 11 is increased or the shape is changed depending on the thickness, the photosensitive resin layer 4 has a multi-layer structure. Therefore, as shown in FIG. When the photosensitive resin layer 4 is formed, since the photosensitive resin layer 4 is colored, the field of view of the reference hole portion becomes dark, and the positional shift between the reference hole 3a and the alignment mark 6 of the mask is optically changed. There also arises a problem that it is difficult to accurately match with a microscope. As a result, the number of man-hours increases and the cost increases.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and it is possible to prevent positional deviations of an ink flow path, an energy working chamber, and an ink supply port by a simple method, and to obtain a stable ink discharge characteristic. An object of the present invention is to provide a low-cost inkjet head.

[0008]

An ink jet head according to the present invention comprises an ink discharge port, an energy action chamber, an ink supply port, and the ink discharge port, the energy action chamber, and the ink supply port on a substrate and a cover plate. At least one wall surface of the communicating ink flow path is formed of a photosensitive resin, and has an energy generating element used to discharge ink disposed corresponding to the ink flow path or the energy action chamber. In an ink jet head, a photosensitive resin layer is formed on a substrate and a cover plate provided with a reference hole serving as a reference at the time of exposure mask alignment and bonding, excluding the reference hole, and exposure is performed based on the reference hole, and then development is performed. Then, the ink discharge port, the energy action chamber, the ink supply port, and the ink flow path are formed at predetermined positions. Next, the substrate and the cover plate are aligned and joined based on the reference hole.

[0009]

EXAMPLES The present invention will be described below with reference to specific examples, but the present invention is not limited to these examples.

First, a method for manufacturing an ink jet head according to the present invention will be described in detail with reference to the drawings. First, as shown in FIG. 1, a substrate 1 made of a suitable material such as glass, plastic, ceramic, metal or the like, on which an energy generating element 2 for discharging ink such as a heating element or a piezoelectric element is provided, is exposed and bonded. The two alignment reference holes 3 are vertically and horizontally symmetrical with respect to the center of the substrate 1 and are spaced apart from the positions where the ink flow path, the energy action chamber, and the ink supply port are formed. Drilling is performed by a known method such as pressing or etching when the substrate is metal.

Next, after cleaning and drying the surface of the substrate 1, a photosensitive resin layer 4a is formed as shown in FIG.
At this time, the photosensitive resin layer 4a is not formed in the positioning reference hole 3. Alternatively, even if formed, the photosensitive resin layer 4a around the alignment reference hole 3 is removed before exposure to leave a cavity. As the photosensitive resin used here, a known photosensitive resin can be used irrespective of liquid type or film type, positive type or negative type. The photosensitive resin layer can be formed by a known method such as a roll coater, a spin coater, a spray coater, and a hot pressure roller laminator. Among these, the method of laminating a dry film photoresist with a hot-press roller laminator is preferable from the viewpoint of workability and uniformity of the layer thickness. In this embodiment, a case where a negative type dry film photoresist is used for a photosensitive resin layer will be described.

Next, as shown in FIG. 3, the photosensitive resin layer 4a
An exposure mask 5 having a predetermined pattern is superimposed thereon. The substrate 1 is finely moved back and forth and left and right while observing the positional deviation between the alignment reference hole 3 of the substrate and the alignment mark 6 of the exposure mask with an optical microscope or the like to minimize the amount of deviation. After that, exposure is performed. By this step, the photosensitive resin layer 4a is divided into a cured portion (exposed portion) and a solubilized portion (unexposed portion).

Next, a new photosensitive resin layer 4b is formed on the photosensitive resin layer 4a which has been subjected to the exposure step in order to increase the energy working chamber. The method for forming the photosensitive resin layer 4b may be the same as the method for forming the photosensitive resin layer 4a formed in FIG.

Next, as shown in FIG. 4, exposure is performed in the same manner as in FIG. At this time, as shown in FIG. 4, since the photosensitive resin layer 4 is not formed in the alignment reference hole 3 at the time of exposure, the reference hole 3 is aligned with the alignment mark 6 of the exposure mask.
Can be accurately identified in a short time because the position deviation state can be clearly seen with an optical microscope. When a negative photosensitive resin is used, the photosensitive resin layer 4a is double-exposed, but does not affect the dimensional accuracy because the light attenuated after reacting in the photosensitive resin layer 4b arrives. This process of forming and exposing the photosensitive resin layer is repeated until a photosensitive resin layer 4 having a desired thickness is obtained. Then, as shown in FIG. 5, the solubilized portion of the photosensitive resin layer 4 is developed using a developer. By dissolving and removing, the ink flow path groove, the energy action chamber groove, and the ink supply port groove are obtained at predetermined positions with respect to the reference hole 3. As the developer, a known developer corresponding to the type of the photosensitive resin can be used. FIG. 5 shows a case where the development step is performed after the photosensitive resin layer formation and exposure steps are repeated three times.

Next, as shown in FIG. 6, an orifice plate 8 on which an orifice 7 made of an appropriate material of glass, plastic, ceramic, metal or the like is formed, is also subjected to the same steps as the substrate (perforation, photosensitive resin layer). (Coating, exposure, and development) to form ink channel grooves, energy action chamber grooves, and ink supply port grooves at predetermined positions with respect to the reference hole 3.

Next, as shown in FIG. 7, the substrate 1 on which the ink flow channel groove, the energy action chamber groove, and the ink supply port groove are formed.
And the orifice plate 8 to obtain an ink flow path, an energy action chamber, and an ink supply port. As shown in FIG. 7, since the positioning reference hole 3 at the time of exposure is used as it is, the positional deviation amount between the substrate 1 and the ink flow channel between the orifice plate 8 is
The positional deviation due to the variation in the distance between the two holes, which occurs when the exposure mask alignment reference hole 3a of the substrate 1 and the orifice plate 8 used at the time of exposure as in the conventional example and the bonding reference hole 3b used at the time of bonding are different. Does not occur.

FIG. 8 is a perspective view of the ink jet head obtained by this embodiment, and FIG. 9 is a cross-sectional view of the ink jet head of FIG. The orifice 7 is provided on the orifice plate 8 and the energy generating element 2 is provided on the substrate 1.
In the case of being provided on the upper surface of FIG. Hereinafter, a comparative example will be described in more detail with reference to specific examples.

[First Embodiment] First, a nickel substrate (10 m long) on which an energy generating element for discharging ink is provided.
m, 30 mm wide) and a circular hole for alignment reference with a diameter of 1 mm on the center line in the vertical direction.
It is formed at two places by a press method with a distance between holes of 28 mm.

Next, a negative type dry film photoresist (trade name "Audil", manufactured by Tokyo Ohka Kogyo Co., Ltd., 55 μm in thickness, 26 mm in width) was placed on a nickel substrate at a temperature of 80 to 100 ° C. using a hot-press roller laminator. , 30-
Lamination is performed at a feed speed of 40 cm / min and a pressure of 1 to ³ kg / cm ² . Dry film photoresist is 26m width shorter than the distance (28mm) between two alignment reference holes
Since m is used, it is not laminated on the reference hole, but remains hollow.

Next, the nickel substrate is finely moved back and forth and left and right while observing the positional deviation between the alignment reference hole and the center of the alignment mark of the exposure mask with an optical microscope, thereby performing accurate alignment. The alignment mark is slightly larger (1.002 mm) and smaller (0.998 m) than the reference hole diameter.
Since the shape includes the arc of m), positioning is performed so that the reference hole is inserted between the two arcs.

Next, using a super-high pressure mercury lamp, 70 mJ / c
Exposure is performed with a light amount of m ² . After this bonding and exposure are repeated a total of three times, 1,1,1-trichloroethane is sprayed using a spray to remove unexposed portions, and ink flow grooves and energy action chambers are formed in the central portions inside the two reference holes. A groove and an ink supply port groove are obtained.

Next, the stainless steel substrate having an orifice has the same two steps as the nickel substrate (drilling, coating of the photosensitive resin layer, exposure, development), and two ink channel grooves, energy action chamber grooves, and ink supply port grooves. Formed in the center of the inside of the hole.

Next, the nickel substrate and the stainless steel substrate are overlapped so that the ink flow channel groove, the energy action chamber groove, and the ink supply port groove face each other, and are aligned with the positioning reference hole at the time of exposure and the positioning pin of the bonding jig. I do. Next, the superposed nickel substrate and stainless steel substrate were bonded at a temperature of 150 ° C. for 10 minutes using a bonding jig at 470 g / cm ^2.
Ink pressure, energy action chamber,
Obtain the ink supply port.

The ink-jet head thus obtained was purified water: ethanol: glycerin: dye = 90:
When printing was performed using an inkjet ink composed of 4: 4: 2 (weight ratio), the ink ejection speed was 9 to 10.
m / sec, ink weight = 0.10 to 0.12 μg, and high-speed, high-density printing could be stably performed. Also,
The positional deviation of the ink flow path, the energy action chamber, and the ink supply port between the nickel substrate and the stainless steel substrate of the obtained inkjet head was about 5 μm.

[Comparative Example 1] First, a nickel substrate (10 m long) on which an energy generating element for discharging ink was provided.
(m, 30 mm in width), two round holes dedicated to exposure mask alignment are formed at two positions on the left and right at positions symmetrical with respect to the center line in the vertical direction at a distance between holes of 25 mm by a press method. At the same time, a round hole dedicated for positioning at the time of joining is 1 mm in diameter and 2 on each side.
It is formed by pressing in different places.

Next, a negative type dry film photoresist (trade name "Audil", manufactured by Tokyo Ohka Kogyo Co., Ltd., 55 μm in thickness, 26 mm in width) was placed on a nickel substrate at a temperature of 80 to 100 ° C. using a hot and pressure roller laminator. , 30-
Lamination is performed at a feed speed of 40 cm / min and a pressure of 1 to ³ kg / cm ² . Since the width (26 mm) of the dry film photoresist is wider than the distance between the two reference holes (25 mm), the reference holes are laminated and closed.

Next, the nickel substrate is finely moved forward, backward, left and right while the positional deviation between the alignment reference hole and the center of the alignment mark of the exposure mask is observed with an optical microscope, thereby performing accurate alignment. The alignment mark is slightly larger (1.002 mm) and smaller (0.998 m) than the reference hole diameter.
Since the shape includes the arc of m), positioning is performed so that the reference hole is inserted between the two arcs.

Next, 70 mJ / c using an ultra-high pressure mercury lamp
Exposure is performed with a light amount of m ² . After this bonding and exposure are repeated a total of three times, 1,1,1-trichloroethane is sprayed using a spray to remove unexposed portions, and ink flow grooves and energy action chambers are formed in the central portions inside the two reference holes. A groove and an ink supply port groove are obtained.

Next, the stainless steel substrate having an orifice is formed in the same steps as the nickel substrate (drilling, coating of the photosensitive resin layer, exposure, development), and the ink flow channel groove, the energy action chamber groove, and the ink supply port groove are formed as reference holes. It is formed at the inner center.

Next, the nickel substrate and the stainless steel substrate are overlapped so that the ink flow channel groove, the energy action chamber groove, and the ink supply port groove face each other, and are aligned with the positioning reference hole at the time of exposure and the positioning pin of the bonding jig. I do. Next, the superposed nickel substrate and stainless steel substrate were bonded at a temperature of 150 ° C. for 10 minutes using a bonding jig at 470 g / cm ^2.
Ink pressure, energy action chamber,
Obtain the ink supply port.

The ink-jet head thus obtained was purified water: ethanol: glycerin: dye = 90:
When printing was performed using an inkjet ink having the same composition as in the example consisting of 4: 4: 2 (weight ratio), the ink ejection speed = 5 to 10 m / sec, and the ink weight = 0.05 to
0.12 μg, and high-speed and high-density printing could be stably performed. Further, the positional deviation of the ink flow path, the energy action chamber, and the ink supply port between the nickel substrate and the stainless steel substrate of the obtained inkjet head was about 15 μm.

As described above, in this embodiment, since the positional deviation is smaller than that of the conventional example by about 10 μm, variations in the ink ejection speed and the ink weight are reduced.

[0033]

As described above, according to the method of manufacturing an ink jet head of the present invention, a photosensitive resin layer is formed on a substrate provided with a reference hole as a reference for aligning an exposure mask and a cover plate except for the reference hole. After forming, exposing based on the reference hole and developing, the ink discharge port, the energy action chamber, the ink supply port, and the ink flow path are formed at predetermined positions. Next, the substrate and the cover plate are aligned and joined based on the same reference hole. For this reason, the ink flow path, the energy action chamber,
The displacement of the ink supply port can be prevented by a simple method. Therefore, there is an advantage that a high-density inkjet head having stable ink ejection characteristics can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a substrate that has been perforated and shows a manufacturing process of an inkjet head according to the present invention.

FIG. 2 is a schematic cross-sectional view of a substrate on which a photosensitive resin layer is formed, showing a process of manufacturing an ink jet head according to the present invention.

FIG. 3 is a schematic cross-sectional view of a substrate in which a mask is overlaid on a photosensitive resin layer and the photosensitive resin is exposed in a step subsequent to FIG. 2 and illustrating a manufacturing process of the inkjet head according to the present invention.

FIG. 4 is a view showing a manufacturing process of the ink jet head according to the present invention, in a process subsequent to FIG. 3, in which a photosensitive resin is further formed on the exposed photosensitive resin, and then a mask is overlaid thereon to expose the photosensitive resin. FIG. 3 is a schematic sectional view of FIG.

FIG. 5 is a schematic cross-sectional view of a first substrate showing a manufacturing process of an ink jet head according to the present invention, in which lamination and exposure of a photosensitive resin are repeated to a desired thickness and development is performed.

FIG. 6 is a schematic cross-sectional view of an orifice plate after development, showing a process of manufacturing an ink jet head according to the present invention.

FIG. 7 is a schematic cross-sectional view showing a manufacturing step of the inkjet head according to the present invention, which is a joining step following FIG. 6;

FIG. 8 is a schematic perspective view of an inkjet head manufactured by the manufacturing method of the present invention.

FIG. 9 is a cross-sectional view illustrating the inkjet head manufactured by the manufacturing method of the present invention when cut at a position indicated by a dashed line XX ′ in FIG.

FIG. 10 is a schematic diagram of an exposure mask alignment method.

FIG. 11 is a schematic perspective view of an inkjet head manufactured by a conventional manufacturing method.

FIG. 12 is a schematic sectional view of a joining step of an inkjet head manufactured by a conventional manufacturing method.

FIG. 13 is a cross-sectional view showing an inkjet head manufactured by a conventional manufacturing method, which is cut at a position indicated by a chain line YY 'in FIG.

FIG. 14 is a schematic cross-sectional view of a substrate on which the photosensitive resin is exposed after the photosensitive resin is further formed on the exposed photosensitive resin, showing a manufacturing process of the inkjet head according to the present invention. is there.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Energy generation element 3a, 3b Positioning reference hole 4a, 4b Photosensitive resin layer 5 Exposure mask 6 Exposure mask alignment mark 7 Orifice 8 Orifice plate 9 Ink channel groove 10 Ink supply port groove 11 Energy action chamber groove 12 Exposure pattern

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41J 2/16 B41J 2/045 B41J 2/055 H01L 21/30

Claims (3)

(57) [Claims] At least one wall surface of an ink discharge port, an energy action chamber, an ink supply port, and an ink flow path communicating the ink discharge port, the energy action chamber, and the ink supply port is formed on a substrate and a cover plate. An ink jet head having an energy generating element formed of a photosensitive resin and used for discharging ink disposed in correspondence with the ink flow path or the energy action chamber; An ink-jet head, wherein a reference hole serving as a reference for alignment at the time of joining is formed as a cavity without forming a photosensitive resin layer. 2. The reference hole is formed in a circular shape, and is vertically or horizontally symmetrical with respect to the center of the substrate and the cover plate, and is located at a position further away from where the ink flow path, the energy action chamber, and the ink supply port are formed. 2. The ink jet head according to claim 1, wherein the ink jet head is provided at a plurality of locations. 3. The method for manufacturing an ink jet head according to claim 1, wherein (a) a step of providing a reference hole as a reference for aligning an exposure mask in the substrate and the cover plate;
Forming a photosensitive resin layer on the substrate and the cover plate,
(C) exposing a required portion of the photosensitive resin layer to a predetermined position with reference to the reference hole; (d) removing an unexposed portion of the photosensitive resin layer; and (e) the substrate And a cover plate are aligned with respect to the reference hole and joined in the order of the steps.