JPH06255104A - Ink jet printing head and production thereof - Google Patents

Abstract

PURPOSE:To stably obtain the same shape even when a plurality of the nozzle shapes of nozzle opening parts are provided, to keep the reliability of a joining part and to enhance the durability of an edge tool. CONSTITUTION:The joined body of a passage substrate 17 forming nozzles 19, pressure chambers and ink passages becoming supply ports on its surface and an elastic plate 16 composed of a membrane transmitting the emitting pressure of ink is subjected to cutting molding by a sharp edge tool 8 to form nozzle opening parts 22. The cut part of the elastic plate 16 is composed of a synthetic resin and the cutting thereof is performed from the elastic plate 16 in such a state that the cutting penetration of the edge tool coincides with the inclination of the side surfaces of the ink passages.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording head of an ink jet printer for forming an ink image on a recording medium such as recording paper by ejecting ink droplets according to a print signal and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a method of manufacturing an ink jet type print head in which a substrate having a plurality of sets of ink flow paths formed by a groove in which a nozzle, a pressure chamber and a supply port communicate with each other and a top plate are adhered to each other is disclosed in Japanese Patent Application Laid-Open No. HEI-1. In JP-A-228861, a recording head of a so-called on-demand type ink jet printer, which ejects ink droplets according to a print signal, is described as an example.

In the prior art, the production of the vertical edge of the nozzle, ie the nozzle opening, is carried out by cutting or polishing.

[0004]

Reducing the size of the recording head,
As the density is increased, the dimensions of the nozzles, the pressure chambers, and the communicating ink channels that serve as the supply ports become smaller. However, in the conventional manufacturing method by cutting or polishing the nozzle opening,
Excessive stress is applied to the minute member, which causes damage due to heat generation, nozzle clogging due to burr in the nozzle, or cracks, chips or burrs around the nozzle opening. Moreover,
According to the manufacturing method, a joint between a flow path substrate that forms a nozzle, a pressure chamber, and a communicating ink flow path that forms a supply port on the surface and a plate-shaped member that transmits the ink discharge pressure to the pressure chamber facing the flow path substrate is also formed. A load is applied, and the reliability of the ink flow path shape or the ink insulation between the flow paths is impaired.

Further, in cutting, which is a processing method, a processing load is applied to the same position of the cutting tool, resulting in a markedly poor durability of the cutting tool.

Here, the problems of the conventional manufacturing method will be described in detail with reference to FIGS. 9 and 10. Flow channel substrate 17 and elastic plate 16
The jointed body with the plate-shaped member is composed of a combination of the elastic plate 16 having a low rigidity and the flow path substrate 17 having a high rigidity for transmitting the ink ejection pressure, and the jointed portion is provided with a direction which easily leads to breakage. Have. Therefore, as shown in FIG. 9, when the angle D ′ of the elastic plate 16 with respect to the cutting tool 8 is 90 degrees or more, the peeling failure F of the elastic plate 16 from the flow path substrate 17 occurs. Further, as shown in FIG. 10, even when the elastic plate 16 does not come off when the angle D ′ is 90 degrees or less, a processing load is applied to the joint end portion of the flow path substrate 17 and the elastic plate 16 having low strength, and the nozzle opening A crack around the portion 22, cracks 30, a floating portion 31 at the joint, and a deformation 32 of the member occurred.

[0007]

In the ink jet head of the present invention, a flow path substrate forming a communicating ink flow path serving as a nozzle, a pressure chamber and a supply port is made of synthetic resin on the surface,
The plate-shaped member that transmits the ink ejection pressure to the pressure chamber that is joined to face the flow path substrate is composed of a metal or ceramics and a synthetic resin, or an ink jet print head composed of a single synthetic resin, In joining the flow path substrate and the plate-shaped member on the plane perpendicular to the nozzle of the flow-path substrate to integrally cut with a blade to form the nozzle opening, the cutting portion of the plate-shaped member is a composite. It is characterized by being composed of resin.

[0008] The nozzle opening is formed by cutting with the blade tool moving in a certain direction with respect to the joined body of the flow path substrate and the plate-like member, and the blade tool is the ink flow path of the flow path substrate. The cutting is introduced from the side of the plate-shaped member in the direction corresponding to the inclination of one of the side surfaces.

[0009]

EXAMPLES The structure of an ink jet print head according to the present invention and the method for manufacturing the same will be described in detail below with reference to examples. FIG. 1 is a diagram for explaining the manufacturing method of the present invention. FIG. 2 is an exploded perspective view of an ink jet type print head utilizing displacement of a piezoelectric element in the direction of an applied electric field as an embodiment of the present invention. FIG. 3 is a sectional view taken along the line AA in FIG. 2 and is a diagram for explaining a driving method. FIG. 7 is a sectional view of an ink jet type print head using another driving method. FIG. 8 is a cross-sectional view of an inkjet print head using another driving method.

In these drawings, reference numeral 17 is a flow path substrate which forms a nozzle 19, a pressure chamber 18 and a supply port 20 together with an elastic plate 16 which is a plate-shaped member. Flow path substrate 17
The convex portion of the partition wall 21 divides the pressure chambers 18, 18 into individual partitions.
Becomes An ink jet type print head is configured by arranging the piezoelectric elements 12 fixed by the base 11 in a one-to-one correspondence at the respective positions in contact with the pressure chambers 18 via the elastic plate 16. When the pressure chambers 18 are arranged at a low density, the piezoelectric element may be arranged at the position where it abuts against the partition wall 21.

An ink jet type print head manufactured according to the present invention will be described with reference to FIG. The piezoelectric element 12 is
An electrode 23 (see FIG. 3) fixed to and electrically connected to the signal electrode 13 of the base 11 is provided on one side surface, and an electrode 24 fixed to and electrically connected to the common electrode 14 is provided on the other side surface.
(See FIG. 3) are provided. The electrode 23 and the electrode 24 are connected to the drive circuit 15 via the signal electrode 13 and the common electrode 14, respectively. The piezoelectric elements 12 are arranged in parallel on the base 11.

The piezoelectric element 12 has a comb-shaped structure, and a plurality of piezoelectric elements 12 are formed in parallel. These are cut with a dicing saw, a wire saw, or the like, for example, and a full cut for cutting the piezoelectric element 12 to the surface of the base 11 or a half cut that does not reach the base 11 is performed. The material of the piezoelectric element 12 is lead zirconate titanate (PZT) here, and either a single-layer piezoelectric element or a laminated piezoelectric element can be used. In this embodiment, a single layer piezoelectric element is used for description.

In this embodiment, the signal electrode 13 is formed by fixing the piezoelectric element block to the base 11 and then by the cutting means, the base 11 is formed.
By cutting up to the surface, each piezoelectric element 12 is formed as an independent electrode. The common electrode 14 electrically connects a thin film such as a copper foil to a part of the electrodes 24 of the plurality of piezoelectric elements 12.

The flow path substrate 17 is integrally formed with a groove forming a pressure chamber 18 and a nozzle 19 communicating with the groove. The flow path substrate 17 can be easily formed by injection molding of plastic, for example. Other techniques include molding by etching with a photosensitive resin and the flow path substrate 17
The partition wall 21 and the other portions can be separately formed by press working, etching, etc., and then fixed to each other. However, in this case, since the nozzle opening surface 22 of the continuous nozzles 19, 19 ... Is cut by a sharp cutting tool, a large number of them are simultaneously manufactured by injection molding using synthetic resin as a basic material.
Therefore, the side wall of the ink flow path such as the pressure chamber 18 and the nozzle 19 has an inclination in consideration of releasability.

Since the elastic plate 16 needs elasticity for transmitting the ink discharge pressure from the piezoelectric element 12, it is a thin film of metal, for example, electroformed nickel of about 1 to 2 μm or synthetic resin, for example, a thin film of polyimide of about 5 μm. Consists of

Next, the operation of the ink jet print head of this embodiment will be described. The ink ejection operation will be described with reference to FIG. Drive circuit 15 (see FIG. 2) to signal electrode 1
A signal is applied to 3 and is transmitted to one electrode 23 of the piezoelectric element 12. Since the other electrode 24 of the piezoelectric element 12 connected to the common electrode 14 has a common potential, a piezoelectric effect is generated by a change in the potential of the electrode 23 due to signal transmission, and the piezoelectric element 12 is pressed against the base 11 as a reference. It is displaced in the direction of the chamber 18. The driving method according to the present invention will be described based on this operation.

As shown in FIG. 3A, the piezoelectric element 12 displaces the pressure chamber 18 of the elastic plate 16 fixed to the piezoelectric element 12 in the B direction for pressing the pressure chamber 18, thereby causing a change in the volume of the pressure chamber 18 and causing a change in the ink discharge dynamic pressure. Occurs and ink is ejected. Further, as the next operation, as shown in FIG. 3B, the piezoelectric element 12 displaces the elastic plate 16 fixed thereto in the pressing release C direction, thereby causing a change in the volume of the pressure chamber 18 to increase, and an ink supply dynamic pressure is generated. Then, the ink fills the pressure chamber 18. Pressure chamber 1 that communicates the above operation to the nozzle 19 required for printing
An ink image can be formed on a medium such as paper by selectively transmitting a signal to the piezoelectric element 12 in contact with 8.

FIG. 1 is a diagram for explaining a method of manufacturing a nozzle opening portion according to the present invention. The nozzle opening 22 is processed by moving the sharp cutting tool 8 in the E direction or the nozzle opening 2
This can be easily done by moving 2 in the opposite E direction. In this figure, 17 is a flow channel substrate, and a plurality of nozzles 19 are provided in the flow channel substrate 17. Reference numeral 16 is an elastic plate, which is joined to the flow path substrate 17 to form the nozzle opening 22 at the edge thereof.

Here, the structure and manufacturing method which are the gist of the present invention will be described. The purpose is to easily form the plurality of nozzle opening shapes of the joined body of the flow path substrate 17 and the elastic plate 16 into the same shape. First, the nozzle opening 22
At the time of processing, it is necessary to firmly fix the joined body of the flow path substrate 17 and the elastic plate 16 on the same frame as the frame to which the blade 8 is fixed so as not to cause processing shake due to vibration from the surroundings. And Then, in order to prevent the elastic plate 16 from peeling off from the flow path substrate 17 which is a feature of the present invention, the cutting tool 8 is installed so as to enter from the elastic plate 16 side, and the cutting tool is reduced in order to reduce the load on the upper cutting tool 8. 8 has an angle,
When the angle is in an arbitrary range of 90 degrees> D ≧ 0 degrees, a processing load is applied to the joint between the flow path substrate 17 and the elastic plate 16 as described above, and cracks around the nozzle opening 22 or chipping or deformation of members. Will occur. Therefore, in order to reduce the cutting load on the nozzle opening 22 and facilitate the cutting, the rigidity of the cut portion of the elastic plate 16 is reduced. Specifically, the elastic plate 1
If 6 consists of a combination of metal and synthetic resin, no metal is used in the cutting part. Further, even if it is made of a single synthetic resin material, the resin thickness of the cut portion is made thin.

Here, an embodiment from the joining of the flow path substrate 17 and the elastic plate 16 to the processing of the nozzle opening 22 is shown in FIGS.
This will be described with reference to FIG. The flow path substrate 17 is manufactured by injection molding using polysulfone or polycarbonate as a material. The elastic plate 16 is made of a metal having chemical resistance and weather resistance, such as stainless steel foil, and one surface of the elastic plate 16 is coated with a thin layer of a synthetic resin having chemical resistance and weather resistance, such as a polyimide resin, to form a base material. This is used as an elastic portion, and a necessary portion of metal is etched and formed by photolithography. When the material is a synthetic resin, for example, a single polyimide material selected for the same reason as above, the elastic portion and the cutting portion are etched and formed by photolithography to the required amount. FIG. 4 shows an embodiment of a method of manufacturing the elastic plate 16 made of metal and synthetic resin. First, stainless steel 4
0 is coated with polyimide 41. Next, a resist 42 is applied so that the stainless steel 40 other than the portion where the polyimide 41 needs elasticity is not etched. Then, the elastic plate 1 is formed by etching the stainless steel 40.
6 is manufactured. In particular, the portion where the stainless steel removal is processed as the nozzle opening 22 (shown in FIG. 5G) is always performed.

Next, referring to FIG. 5, the flow path substrate 17 and the elastic plate 1 are shown.
The joining with 6 will be described. As a characteristic of the member, the elastic plate 16 has a structure in which the thickness of the joint portion is partially thin and pressure is not applied during the joint. In particular, it is thin to facilitate the cutting of the cut portion, which is a feature of the present invention (G in the figure). Therefore, in order to compensate for the member thickness at the time of bonding, the jig 50 is formed by the reverse mask of the elastic plate 16 and overlapped at the time of bonding to obtain a bonded body with a good bonded state.

Next, the nozzle opening 22 is processed. As shown in FIG. 6, the flow path substrate 17 has an inclined side wall on the ink flow path by injection molding. Therefore, the cutting approach angle of the cutting tool 8 is made parallel to one inclination of the partition wall 21 and the cutting is advanced. At this time, although the cutting progress direction is different with respect to the other one of the inclinations H, since the cutting is performed in the direction in which the width of the partition wall 21 becomes wider, the cutting can be performed around the nozzle opening without cracks or chips. Further, since the elastic plate 16 also has a structure that can be easily cut, stable processing can be performed without breaking the joint portion of the elastic plate 16.

FIG. 7 is a partial sectional view of an ink jet type print head utilizing displacement of a piezoelectric element in a direction perpendicular to an applied electric field as another embodiment of the present invention.
From the joining of 7 and the elastic plate 16 to the processing of the nozzle opening 22, the same member and the same manufacturing method are basically used as described above.

FIG. 8 is an exploded perspective view of an ink jet type print head using a heating element as another embodiment of the present invention. The plate-shaped member 16 'includes electrodes 13, 14 and a heating element 52 on the surface of the base metal and ceramics.
And its outermost surface is coated with an insulating treatment, for example, polyimide. As a feature of the plate-shaped member 16 ', the position (G' in the figure) that becomes the nozzle opening 22 is made of a single polyimide material. The basic structure of the print head is the same as the structure shown in FIG. 2 described above, and is characterized in that the heating elements 52 are arranged in the pressure chambers 18 in a one-to-one correspondence. The principle of ink ejection pressure generation of the ink jet type print head of the present embodiment is that the heating element 52 generates heat to instantaneously bring the ink into a boiling state to generate bubbles in the pressure chamber 18 and generate dynamic pressure in the ink. . Based on this principle, ink droplets are ejected from the nozzle openings 22.

Also in this structure, the manufacturing method is basically the same as described above from the joining of the flow path substrate 17 and the plate member 16 'to the processing of the nozzle opening 22.

[0026]

As described above, the nozzle opening formed by the flow path substrate of the ink ejecting device and the plate member for transmitting the ink ejecting pressure which are closely arranged in parallel is formed with a sharp cutting tool. By allowing the ink to enter from the elastic plate side in conformity with one inclination of the ink flow path side wall, there is no cracking or chipping around the nozzle opening, and the material composition of the cutting part of the plate-shaped member is easy to cut. The shape of the joint between the substrate and the plate member and its reliability are maintained. Further, since the cutting is made of synthetic resin, the load on the cutting tool is low and the durability is improved. Moreover,
Since the nozzle opening shape can be easily and stably formed without cracking or chipping, the ink ejection characteristics can be improved.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a manufacturing method of the present invention.

FIG. 2 is an exploded perspective view of an ink jet print head showing an embodiment of the present invention.

FIG. 3A is a partial cross-sectional view for explaining a driving method according to the above embodiment (during ink ejection). (B) It is a partial cross-sectional view for explaining the driving method of the above embodiment (during ink supply).

FIG. 4 is a drawing for explaining the manufacturing method of the plate-shaped member of the present embodiment.

FIG. 5 is a diagram for explaining a method of joining the flow path substrate and the plate-shaped member of the present embodiment.

FIG. 6 is a drawing for explaining the manufacturing method of the nozzle openings.

FIG. 7 is a partial cross-sectional view of an ink jet print head showing another embodiment of the present invention.

FIG. 8 is a partial cross-sectional view of an inkjet print head showing another embodiment of the present invention.

FIG. 9 is a diagram for explaining a problem of the conventional manufacturing method.

FIG. 10 is a diagram for explaining problems in the conventional manufacturing method.

[Explanation of symbols]

 11 base 12 piezoelectric element 13 signal electrode 14 common electrode 15 drive circuit 16 elastic plate (plate-shaped member) 17 flow path substrate 18 pressure chamber 19 nozzle 20 ink supply port 21 partition wall 22 nozzle opening 23 piezoelectric element electrode 24 piezoelectric element electrode

Claims (4)

[Claims] 1. A flow path substrate made of synthetic resin having a nozzle, a pressure chamber and an ink flow path formed on its surface, and a plate-like member made of metal or ceramics and synthetic resin, or made of a single synthetic resin. An ink jet type print head for forming a nozzle by joining the above, and cutting the vicinity of the nozzle of the joined body, wherein the rigidity of at least the cutting portion of the plate member is lower than the rigidity of other plate members. Characteristic ink jet type print head. 2. The ink jet print head according to claim 1, wherein the thickness of the cut portion of the plate member is smaller than the thickness of other plate members. 3. The ink jet print head according to claim 1, wherein at least the cutting portion of the plate-shaped member is made of synthetic resin. 4. The nozzle opening is formed by joining the flow path substrate and the plate-like member, and then cutting and advancing a cutting tool from the plate-like member side in a direction corresponding to the inclination of the side wall of the ink flow path of the flow path substrate. A method for manufacturing an ink jet print head, comprising: