JP2005262752A - Inkjet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet head which prevents short-circuiting between extraction electrodes and peeling of the extraction electrodes from occurring without increasing manufacturing processes and does not decrease a yield. <P>SOLUTION: In the inkjet head wherein a plurality of channels 3 for storing ink are provided by forming a plurality of partitions 4 at predetermined intervals on substrates 11 and 12 consisting of a piezoelectric material, and a nozzle plate 6 for discharging the ink is provided on its end, and the electrodes 5 are provided along respective channels 3, and the extraction electrodes 51 are provided by extending the electrodes 5 in the other end directions of the substrates 11 and 12, and these extraction electrodes 51 are connected with en electrodes 81 of a driver electrode 8 to receive feeding of an electric voltage, the shape of the end part of the extraction electrode is made into an arc. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an inkjet head that discharges ink by applying a voltage to an electrode to deform a channel.

  2. Description of the Related Art Conventionally, an inkjet head that discharges ink by applying a voltage to an electrode to deform a channel has a plurality of channels (channel arrays) by providing a plurality of partition walls 4 at predetermined intervals as shown in FIG. 3 is formed, and includes a substrate 10 including an electrode 5 provided along the channel and a take-out electrode 51 in which each of the electrodes 5 is extended.

  In addition, in order to eject the ink supplied from the ink supply port 7 from the ink discharge port 6 a provided in the nozzle plate 6, the electrode 81 of the driver substrate 8 that applies a voltage to the electrode 5 by the drive power supply is used as the extraction electrode 51. Configured to be connected.

  Moreover, as shown in FIG. 10 which is a CC cross-sectional view of FIG. 9, an electrode 5 is formed on the wall surface of each partition wall 4. Since the partition 4 is made of thick substrates 11 and 12 made of two piezoelectric materials having different polarization directions, each electrode 5 has a thickness constituting at least each partition 4 in order to drive the both thick substrates 11 and 12. Although it is formed on the entire surface of both side surfaces extending over the substrate 11 and the thin substrate 12, it is not necessarily formed on the bottom surface.

  The cover member 2 is bonded to the upper surface of the partition wall 4 by using an adhesive such as an epoxy adhesive after the electrode 5 is formed. When the cover member 2 is bonded to the substrate 10, the cover member 2 has a warp, deformation, and thermal expansion coefficient. In order not to cause separation due to the difference, a non-piezoelectric substrate having the same material as the substrate 10 or the same thermal expansion coefficient as the substrate 10 is employed. As a result, the channel 3 is partially formed of the piezoelectric material, that is, the side wall and the bottom wall.

  Moreover, as shown in FIG. 11 which is a DD cross-sectional view of FIG. 9, the cross-sectional shape of the extraction electrode 51 formed by extending the electrode 5 on the surface of the substrate 10 (thick substrate 11) is substantially rectangular. Then, as shown in FIG. 12, which is a perspective view on the side where the driver substrate 8 is connected to the substrate 10, as viewed from the upper surface of the substrate 10 (thick substrate 11) (the surface to which the driver substrate 8 is connected in the thick substrate 11). The planar shape of the extraction electrode 51 is also rectangular.

  In recent years, many ink jet heads with a reduced size and increased nozzle density have been proposed. For example, a compact ink jet head that can be connected to the extraction electrode in a short time and has a higher nozzle density is provided. For this purpose, there has been proposed an inkjet head in which the pitch width of the connection point between the extraction electrode and the driver substrate is 150 μm or less (for example, Patent Document 1).

JP 2002-127422 A (paragraphs [0023]-[0061], FIG. 1)

  However, in the invention described in Patent Document 1, it is disclosed that the pitch width of the connection point between the extraction electrode and the driver substrate is 150 μm or less. In the step of removing unnecessary portions from the metal film to be included, stress is also applied to the necessary portions due to metal bonding, and the take-out electrode may be peeled off from the substrate.

  In addition, with the miniaturization of the internal configuration of the inkjet head and the miniaturization of the inkjet apparatus, the extraction electrode itself tends to be small. Therefore, as described above, even when the pitch width of the connection point between the extraction electrode and the driver substrate is set to 150 μm or less, there is a possibility that the adhesion area decreases and the extraction electrode peels from the substrate.

  Furthermore, when the interval between the extraction electrodes is reduced along with the miniaturization and miniaturization, a short circuit between adjacent extraction electrodes is likely to occur. In order to solve this problem, if the width of the extraction electrode is narrowed, the adhesion area to the substrate made of the piezoelectric body is reduced, and there is a problem that the adhesion force is lowered. In addition, when the number of channels is increased, if the electrodes are peeled off even at one location, all the components cannot be used, resulting in a decrease in yield and an increase in manufacturing cost.

  In addition, since a high voltage flows in the electrode (and the extraction electrode) of the ink jet head, for example, compared to a semiconductor electrode, there may be a problem when the electrode (and the extraction electrode) peels off or a so-called burr occurs. Is higher than semiconductor electrodes. That is, a portion floating due to peeling or burr becomes a resistance component, and when the resistance component increases, noise is generated, leading to a decrease in ink ejection stability. As a result, in the electrode (and the extraction electrode) of the ink jet head using the piezoelectric element, the capacity increases, the time constant increases, and the reaction rate decreases. Therefore, peeling of the electrode (and the extraction electrode) and prevention of burrs have been indispensable issues for ensuring the discharge performance.

  The present invention has been made in view of the above problems, and its purpose is to make the shape of the extraction electrode formed by patterning a specific shape without increasing the number of manufacturing steps. An object of the present invention is to provide an ink jet head that prevents peeling and does not cause a decrease in yield.

  Another object of the present invention is to provide an ink jet head capable of preventing a short circuit between extraction electrodes and securing an adhesive force to a substrate made of a piezoelectric material.

  In order to solve the above problems, an ink jet head according to the invention of claim 1 is provided with a plurality of channels for storing ink by forming a plurality of partition walls at a predetermined interval on a substrate made of a piezoelectric material, A nozzle for ejecting ink is provided at one end, an electrode is provided along each channel, and an extraction electrode is provided by extending the electrode in the direction of the other end of the substrate. In the ink-jet head formed so as to be connected to the electrode of the driver substrate and receive voltage supply, the shape of the end portion of the take-out electrode is arcuate.

  By adopting such a configuration, it is only necessary to change the shape of the mask pattern used when forming the extraction electrode, so that the manufacturing process is not increased and the end of the extraction electrode is formed at the time of creation (particularly lift-off). Since the shape has a predetermined curvature instead of a rectangle in which stress is easily concentrated in the process), it is possible to provide an ink jet head that can prevent peeling of the extraction electrode and does not cause a decrease in yield.

  In order to solve the above-mentioned problem, the inkjet head according to the invention of claim 2 is the inkjet head according to claim 1, wherein the shape of the end portion of the extraction electrode is the substrate when formed on the substrate. The contact surface with is arcuate.

  This configuration indicates that the shape of the end portion of the extraction electrode is a rounded shape at the joint surface between the substrate and the extraction electrode. Accordingly, since stress is unlikely to concentrate on the end portion of the take-out electrode on the joint surface, the take-out electrode can be prevented from being peeled off from the substrate during the lift-off process, and an ink jet head that does not cause a decrease in yield. Can be provided.

  In order to solve the above-described problem, an ink jet head according to a third aspect of the present invention is the ink jet head according to the first aspect, wherein the shape of the end portion of the extraction electrode is an arc shape on the installation surface installed on the substrate. It is characterized by being.

  In order to solve the above-described problem, an ink jet head according to a fourth aspect of the present invention is the ink jet head according to any one of the first to third aspects, wherein the shape of the end portion of the extraction electrode is the length of the channel. It is characterized by a symmetrical shape with the direction as an axis.

  Thus, since the shape of the extraction electrode is symmetric with respect to the direction of the channel row, the prevention of peeling of the electrode can be improved.

  In order to solve the above-described problem, an ink jet head according to claim 5 is the ink jet head according to any one of claims 1 to 3, wherein an end portion of the extraction electrode has a semicircular shape. It is characterized by that.

  In order to solve the above-mentioned problem, an ink jet head according to a sixth aspect of the present invention is the ink jet head according to any one of the first to fifth aspects, wherein the ink jet head has a direction perpendicular to the length direction of the channel of the extraction electrode. The cross-sectional shape is characterized in that the width dimension on the side installed on the substrate is larger than the width dimension on the side connected to the electrode of the driver substrate.

  By adopting such a configuration, it is possible to provide an ink jet head that can further improve the prevention of a short circuit between the extraction electrodes and the prevention of the separation of the extraction electrodes by securing the adhesive force to the piezoelectric body.

  According to the present invention, by providing the shape of the extraction electrode formed by patterning with a specific shape, it is possible to provide an inkjet head that prevents electrode peeling and does not reduce yield without increasing the number of manufacturing steps. Can do. Moreover, while preventing the short circuit between electrodes, the inkjet head which can ensure the adhesive force to a piezoelectric material can be provided.

  Hereinafter, embodiments of an inkjet head according to the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a partially broken perspective view showing an outline of the overall configuration of the ink jet head according to the first embodiment of the present invention. FIG. 2 is a side view showing the configuration of the ink jet head according to the first embodiment of the present invention. As shown in FIG. 1, the inkjet head according to the present invention includes a first substrate 10 composed of a thick substrate 11 and a thin substrate 12 made of a piezoelectric material, and a piezoelectric material similar to the first substrate 10. The thick substrate 21 and the second substrate 20 composed of the thin substrate 22 are joined to each other in opposite directions.

  The thick substrate 11 and the thin substrate 12 (thick substrate 21 and thin substrate 22) are bonded with different polarization directions, and the bonding method can employ bonding using an adhesive such as an epoxy-based adhesive. However, it is not particularly limited as long as joining is possible.

  Here, the piezoelectric material constituting the thick substrate 11 and the thin substrate 12 (thick substrate 21 and thin substrate 22) is not particularly limited as long as a stress change is caused by applying a voltage, and a known material is used. Although a substrate made of an organic material may be used, a substrate made of a piezoelectric nonmetallic material is preferable, and the substrate made of the piezoelectric nonmetallic material is preferably a ceramic substrate formed through processes such as molding and firing. Or a substrate formed without the need for molding or firing. Examples of the organic material include organic polymers and hybrid materials of organic polymers and inorganic materials.

Ceramic substrates include PZT (PbZrO ₃ —PbTiO ₃ , third component added PZT), and the third component is Pb (Mg1 / 2, Nb2 / 3) O ₃ , Pb (Mn1 / 3, Sb2 / 3) O. ₃ and Pb (Co1 / 3, Nb2 / 3) O _{3 and the} like, and further, BaTiO ₃ , ZnO, LiNbO ₃ , LiTaO _{3 and the} like can be used.

  Moreover, as a board | substrate formed without requiring shaping | molding and baking, it can form by the sol-gel method, laminated substrate coating, etc., for example. According to the sol-gel method, the sol is prepared by adding water, an acid or an alkali to a homogeneous solution having a predetermined chemical composition to cause a chemical change such as hydrolysis. Further, by applying a treatment such as evaporation of the solvent or cooling, a sol in which the precursor of the target composition or the precursor of the nonmetallic inorganic fine particles is dispersed can be prepared and used as a substrate. A compound having a uniform chemical composition can be obtained, including the addition of a small amount of a different element, and a metal salt or metal alkoxide soluble in water such as sodium silicate is generally used as a starting material. A compound represented by the formula M (OR) n, which is easily hydrolyzed because the OR group has a strong basicity, and is converted into a metal oxide or a hydrate thereof through a condensation process like an organic polymer. .

  In addition, as a laminated substrate coating, there is a method of vapor deposition from the gas phase, and there are two methods for producing a ceramic substrate from the gas phase: a vapor deposition method by physical means and a production method by chemical reaction of the gas phase or the substrate surface. Furthermore, the physical vapor deposition method (PVD) is subdivided into a vacuum vapor deposition method, a sputtering method, an ion plating method, and the like, and chemical methods include a gas phase chemical reaction method (CVD), a plasma CVD method, and the like. is there.

  The vacuum deposition method as physical vapor deposition (PVD) is a method in which a target substance is heated and evaporated in a vacuum, and the vapor is deposited on a substrate. A sputtering method is a high energy particle on a target substance (target). This is a method that utilizes a sputtering phenomenon in which atoms and molecules on the target surface exchange momentum with the colliding particles and are repelled from the surface. The ion plating method is a method of performing vapor deposition in an ionized gas atmosphere.

In the CVD method, a compound containing atoms, molecules, or ions constituting the film is put into a gas phase state, and then introduced into a reaction part with an appropriate carrier gas, and the film is formed by reacting or precipitating on a heated substrate. In the plasma CVD method, a gas phase state is generated by plasma energy, and a film is deposited by a gas phase chemical reaction in a relatively low temperature range from 400 ° C. to 500 ° C.

  The first substrate 10 is formed with a plurality of rows of grooves 3 parallel to each other at a predetermined interval by using a known grinding machine such as a disc-shaped grindstone (dicing blade), and the channel 3 for storing ink. The drive walls 4 made of the thick substrate 11 and the thin substrate 12 are alternately formed.

  An electrode 5 is formed on the wall surface of each drive wall 4. Since the drive wall 4 is composed of two thick substrates 11 and 12 (thick substrate 21 and thin substrate 22) having different polarization directions, each electrode 5 drives both the thick substrates 11, 12 (21, 22). In order to achieve this, at least the piezoelectric material thick substrates 11 and 12 (21 and 22) constituting each driving wall 4 are formed on the entire surface on both sides, but not necessarily on the bottom surface.

  Here, the metal to be the electrode 5 is platinum (Pt), gold (Au), silver (Ag), copper (Cu), aluminum (Al), palladium (Pd), nickel (Ni), tantalum (Ta), Titanium (Ti) can be used, and gold (Au), aluminum (Al), copper (Cu), and nickel (Ni) are particularly preferable from the viewpoint of electrical characteristics and workability. It is formed.

  Further, an extraction electrode 51 is formed by extending the electrode 5 in the direction of the end of the thick substrate 11 (the “other end” in the present claims), and the extraction electrode 51 is configured as shown in FIG. Thus, the electrode 81 provided on the driver substrate 8 is electrically connected through an anisotropic conductive material.

  Here, in the description of the embodiment of the present invention, the surface on which the groove is formed in the first substrate 10 and the second substrate 20 is referred to as “the surface of the first substrate 10 (second substrate 20)”. . For the driver substrate 8 electrically connected to the first substrate 10 via the extraction electrode 51, the surface on which the electrode 81 connected to the extraction electrode 51 is formed is referred to as “the back surface of the driver substrate 8”. The opposite surface is referred to as “the surface of the driver substrate 8”. Therefore, the electrical connection between the first substrate 10 (the front surface of the second substrate 20) and the driver substrate 8 is such that the front surface of the first substrate 10 (the front surface of the second substrate 20) and the back surface of the driver substrate 8 are connected. Are performed in a manner opposite to each other.

  Further, as the anisotropic conductive material, it is preferable to use an anisotropic conductive film (film) having three functions of adhesion, conductivity, and insulation at the same time. As the binder and the conductive particles constituting the anisotropic conductive film, those made of various known materials can be used. In particular, the conductive particles are preferably metal particles. By using the metal particles, the metal particles can break through the oxide film of the aluminum electrode formed by aluminum vapor deposition, and good conduction can be performed. In addition, it is preferable to remove anisotropic conductive rubber as the anisotropic conductive material. In general, anisotropic conductive rubber is disadvantageous for electrode connection of an ink jet head that requires a large current to flow.

  The thick substrate 11 and the thin substrate 12 (thick substrate 21 and thin substrate 22) are provided with a cover material 2 having an ink supply port 7 that covers most of the channel 3 while leaving the extraction electrode 51.

  The material of the cover substrate is not particularly limited, and may be a substrate made of an organic material, but a substrate made of a non-piezoelectric nonmetallic material is preferable. As the substrate made of this non-piezoelectric nonmetallic material, alumina, nitride It is preferably selected from at least one of aluminum, zirconia, silicon, silicon nitride, silicon carbide, quartz, and PZT.

This non-piezoelectric non-metallic substrate includes, for example, a ceramic substrate formed through a process such as molding and firing, or a substrate formed without requiring molding and firing, and is formed through a process such as firing. As the ceramic substrate to be used, for example, Al ₂ O ₃ , SiO ₂ , a mixture or mixture thereof, ZrO ₂ , BeO, AlN, SiC, or the like can be used. Examples of the organic material include organic polymers and hybrid materials of organic polymers and organic substances.

  In addition, the nozzle plate 6 has an ink discharge port 6a opened at a position corresponding to the channel 3, and is bonded to the end face of the piezoelectric material 1 after the cover member 2 is bonded by an epoxy adhesive or the like. .

  The ink jet head according to the present invention is characterized in that the take-out electrode is processed, and particularly in this embodiment, the take-out extending in the direction of the end of the board 10 on the side where the driver board 8 is installed. The end of the electrode is processed into an arc shape when viewed from above. Thereby, stress concentration at the end of the take-out electrode during lift-off is reduced, and peeling at the end of the take-out electrode can be prevented.

  The shape of the end portion of the extraction electrode 51 of the present embodiment will be described below. FIG. 3 is a top view illustrating the configuration of the extraction electrode 51 and the driver substrate 8 in the first embodiment of the inkjet head according to the present invention. As shown in FIG. 3, the shape of the end portion of the extraction electrode 51 of the present embodiment is an arc shape toward the driver electrode 8 side, that is, a round shape instead of a rectangle when viewed from the upper surface of the substrate 10. There is no. The shape of the end portion of the extraction electrode 51 is desirably symmetric with respect to the length direction of the channel 3 (not shown) (the direction in which the extraction electrode 51 extends from the electrode 5). This is because the end portion of the extraction electrode 51 has a symmetrical shape, so that the holding force for the thick substrate 11 is not distorted.

  On the other hand, the driver substrate 8 made of a flexible substrate or the like has an electrode 81 extending on one end thereof formed on the back surface corresponding to each extraction electrode 51. Then, the extraction electrode 51 and the electrode 81 are electrically connected via an anisotropic conductive material so that the back surface of the driver substrate 8 is placed on the surface of the thick substrate 11.

  Next, a manufacturing process in the first embodiment of the inkjet head according to the present invention will be described below with reference to the drawings.

  4A to 4G are cross-sectional views illustrating the manufacturing process in the first embodiment of the inkjet head according to the present invention. As shown in FIG. 4A, in the present embodiment, firstly, a first substrate 10 and a second substrate 20 are prepared, and the first substrate 10 includes a thick substrate 11 and a thin substrate 12. Similarly, the second substrate 20 includes a thick substrate 21 and a thin substrate 22.

  Next, as shown in FIG. 4B, a dry film 13 is attached on the thin substrate 12 of the first substrate 10, and a glass substrate (not shown) is provided with a pattern for forming electrodes on the dry film 13. The electrode pattern dry film 13 is removed by exposure and development processing.

  Further, as shown in FIG. 4C, a channel 3 is formed on the first substrate 10 by grooving with a dicing disk in contact with the end of the electrode pattern, and Al (aluminum) deposition is performed. After that, the remaining dry film 13 (dry film other than the electrode pattern) is dissolved and removed together with aluminum deposited thereon to form an electrode 5 in the channel 3 and take out connected to the electrode 5 The electrode 51 is formed.

  Similarly, a dry film 13 is attached on the thin substrate 22 of the second substrate 20, and a glass substrate (not shown) on which a pattern for forming an electrode is formed is disposed on the dry film 13. Exposure as a mask and development are performed to remove the electrode film dry film 13. In addition, the second substrate 20 is similarly grooved to form the channel 3, and after performing the Al deposition, the remaining dry film 13 is removed together with the aluminum deposited thereon. An electrode 5 is formed in the channel 3 and a take-out electrode 51 connected to the electrode 5 is formed.

  Next, as shown in FIG. 4D, the first substrate 10 and the second substrate 20 are provided with ink intakes that cover most of the channels 3 and 3 while leaving the extraction electrodes 51 and 51. Cover substrates 2 and 2 are provided, and the first substrate 10 and the second substrate 20 are bonded to the side opposite to the side on which the cover substrates 2 and 2 are provided (FIG. 4E), and the center portion is cut. Thus, the nozzle plate 6 having the ink discharge ports 6a is provided in the portions corresponding to the channels 3 and 3, and two ink jet head bodies are manufactured (FIG. 4F).

  Thereafter, as shown in FIG. 4G, each of the two inkjet head bodies includes actuators 7 for supplying ink to the channels 3 and 3 to the first substrate 10 and the second substrate 20. 7 and connecting the electrodes 81 and 81 of the driver boards 8 and 8 to the extraction electrodes 51 and 51 through an anisotropic conductive material using a heating and pressing tool or the like, and simultaneously manufacturing two inkjet heads To do.

  Thus, as shown in FIGS. 1 to 4, the ink jet head of the present invention is provided along the channel row of the first substrate 10 formed through the plurality of partition walls 4 and the partition walls 4. A first substrate 10 having an electrode 5 and a take-out electrode 51 extending from each electrode 5, a channel row of the second substrate 10 formed via a plurality of partition walls 4, and each partition wall 4 A second substrate comprising the electrodes 5 provided along the electrodes 5 and a take-out electrode 51 extending from each of the electrodes 5, and driver substrates 8 and 8 electrically connected to both the substrates 10 and 20, respectively. The first substrate 10 and the second substrate 20 are bonded together.

  Next, as a modification of the present embodiment, the shape of the extraction electrode 51 will be described. FIGS. 5A and 5B are top views showing the shape of the extraction electrode 51 as a modification of the present embodiment. The extraction electrode 51 shown in FIG. 5A has a semicircular end, and the extraction electrode 51 shown in FIG. 5B has a so-called R at the corner of the conventional rectangular extraction electrode 51. It has a different shape. By adopting such a shape, peeling of the extraction electrode 51 can be prevented rather than simply making the shape of the end portion of the extraction electrode 51 into an arc shape.

  In addition, since these shapes may be changed to a pattern of the shape when the extraction electrode 51 is formed, an inkjet head that does not increase the number of steps and does not cause a decrease in yield can be provided. 3 and 5 exemplify the connection between the first substrate 10 (thin substrate 11) and the driver substrate 8 with respect to the connection between the extraction electrode 51 and the electrode 81 of the driver substrate 8, the second The same applies to the substrate 20.

  In the above embodiment, the electrode of the ink jet head is formed using a dry film. However, it can be manufactured in a form in which an ultraviolet reaction type (ultraviolet curing type) resist is applied instead of the dry film. . In the same manner as the dry film, the electrode pattern is baked on the resist by irradiating with ultraviolet rays using the glass substrate on which the electrode pattern is applied as a mask, and the resist of the electrode portion is removed by performing a development process. Groove processing is performed with a dicing disk while being in contact with the portion, and except for the groove portion that becomes the electrode 5 and the channel 3, Au (gold), Ag (silver), Cu (copper) serving as the electrode is formed on the resist-covered substrate. ), Al (aluminum), Cr (chromium), Ni (nickel), and the like, and then the resist is dissolved and removed.

  Further, in the above embodiment, the description has been given of the mode in which both the substrates 10 and 20 are joined on the opposite side of the channel 3 provided on each of the both substrates 10 and 20, but the characteristic part of the present invention is the extraction electrode 51. Therefore, the two substrates 10 and 20 may be constituted by either the first substrate 10 or the second substrate 20 and the tribar substrate 8 without being bonded together as described above.

  In the present embodiment, the width dimension of the arc-shaped portion at the end of the extraction electrode 51 (the dimension in the direction orthogonal to the length direction of the channel 3) is the width dimension of the extended portion of the extraction electrode 51, It is desirable to form it at a ratio of 5% to 50% with respect to (the width dimension of the extraction electrode 51 having a conventional rectangular shape). If it is less than 5%, the effect of preventing stress concentration at the lift-off due to the formation of the arc shape cannot be expected, and if it is 50% or more, as described above, the shape of the channel 3 is not symmetrical with respect to the length direction. This is because the adhesive force to the thin substrates 11 and 21 may be distorted, and the effect of preventing stress concentration during lift-off may be reduced.

  Further, in order to prevent stress concentration at the time of lift-off, the straight line (the edge extending linearly from the channel 3) and the curved part (the edge constituting the arc shape) intersect at the straight line. It is desirable that the angle θ formed by the tangent line of the curved portion and the curve portion satisfy 0 ° <θ ≦ 30 ° (when θ = 0 °, the shape of the conventional rectangular extraction electrode is the same).

(Second Embodiment)
Next, a second embodiment of the inkjet head according to the present invention will be described below with reference to the drawings. In the description of the present embodiment, the same description as that of the first embodiment is omitted. Therefore, only the parts different from the description of the first embodiment will be described.

  6A to 6C are cross-sectional views of the substrate and the extraction electrode in the second embodiment of the inkjet head according to the present invention, and the cross-sections of the substrate and the extraction electrode of the conventional inkjet head shown in FIG. Corresponds to the figure. 7A to 7C are perspective views of the substrate and the extraction electrode in the second embodiment of the inkjet head according to the present invention. As shown in FIGS. 6A to 6C and FIGS. 7A to 7C, the cross-sectional shape of the extraction electrode 51 of the present embodiment is the width dimension on the side connected to the electrode 81 of the driver substrate 8. Further, the width of the side installed on the thin substrate 11 is made larger.

  For example, as shown in FIGS. 6 (a) and 7 (a), the extraction electrode 51 has a trapezoidal cross section, or as shown in FIGS. 6 (b) and 7 (b). A mode in which the cross-sectional shape of 51 has a convex shape, or a mode in which the cross-sectional shape of the extraction electrode 51 has a substantially semicircular shape as shown in FIGS. 6C and 7C can be employed. When the cross-sectional shape of the extraction electrode 51 is a trapezoidal shape, the shape is not limited to the isosceles trapezoidal shape as shown in FIGS. 6A and 7A, but the first embodiment described above. Similarly, it is desirable that the channel 3 has a symmetrical shape with the length direction of the channel 3 as an axis. Further, when the cross-sectional shape of the extraction electrode 51 is a substantially semicircular shape, in order to secure the connection surface of the extraction electrode 51 with respect to the electrode 81, as shown in FIGS. 6C and 7C, It is desirable to provide a substantially flush upper surface on the extraction electrode 51.

  In the present embodiment, the width dimension (dimension in the direction orthogonal to the length direction of the channel 3) of the end portion of the extraction electrode 51 on the thin substrate 11, 21 side is a, and the electrode 81 at the end portion of the extraction electrode 51 is a. It is desirable that a / b satisfy 1.1 to 5 when the width dimension (dimension in the direction perpendicular to the length direction of the channel 3) is b. Further, as long as such a condition is satisfied, the cross-sectional shape of the extraction electrode 51 illustrated in FIGS. 6 and 7 is not limited.

  Thus, by making the cross-sectional shape of the extraction electrode 51 a shape in which the width dimension on the side installed on the thin substrate 11 is larger than the width dimension on the side connected to the electrode 81 of the driver substrate 8, Since the distance between the upper surfaces of the adjacent extraction electrodes 51 is increased while maintaining the bonding force to the thin substrate 11, an electrical short circuit between the adjacent extraction electrodes 51 can be prevented.

  In addition, the cross-sectional shape of the extraction electrode 51 in the present embodiment can be formed by preparing two or more mask patterns and performing oblique deposition. In addition, since this oblique vapor deposition should just be performed when forming the electrode 5 in the wall surface of the partition 4, the said shape can be obtained, without increasing the number of processes.

  In FIGS. 6A to 6C and FIGS. 7A to 7C, the shape of the extraction electrode 51 formed on the surface of the thin substrate 11 is shown, and other portions are omitted. The shape of the extraction electrode 51 formed on the surface of the thin substrate 21 is the same as the shape of the extraction electrode 51 formed on the surface of the thin substrate 11.

(Third embodiment)
Next, a third embodiment of the ink jet head according to the present invention will be described below with reference to the drawings. In the description of the present embodiment, the same description as that of the first embodiment and the second embodiment described above is omitted. Accordingly, only the parts different from those of the first embodiment and the second embodiment will be described.

  FIG. 8 is a perspective view showing the shape of the extraction electrode formed on the substrate in the third embodiment of the inkjet head according to the present invention. This figure corresponds to FIG. 7 in the second embodiment described above.

  As shown in FIG. 8, the present embodiment is a combination of the first embodiment and the second embodiment described above. Specifically, as shown in FIG. 7, the shape of the end portion of the extraction electrode 51 is an arc shape when viewed from the surface of the thin substrate 11 in the thickness direction, and is orthogonal to the length direction of the channel 3. The cross-sectional shape of the take-out electrode 51 in the direction is such that the width dimension on the side installed on the thin substrate 11 is larger than the width dimension on the side connected to the electrode 81 of the driver substrate 8.

  In this embodiment as well, the width dimension of the arc-shaped portion at the end of the extraction electrode 51 (the dimension in the direction perpendicular to the length direction of the channel 3) is the same as in the first embodiment described above. It is desirable that the electrode 51 is formed at a ratio of 5% to 50% with respect to the width dimension of the extended portion of the electrode 51 (the width dimension of the extraction electrode 51 having a conventional rectangular shape).

  In order to prevent stress concentration at the time of lift-off, the straight line (the edge extending linearly from the channel 3) and the curved part (the edge constituting the arc shape) intersect at the straight line. It is desirable that the angle θ formed by the tangent line of the curved portion and the curve portion satisfy 0 ° <θ ≦ 30 ° (when θ = 0 °, the shape of the conventional rectangular extraction electrode is the same).

  Further, similarly to the above-described second embodiment, the width dimension (dimension in the direction perpendicular to the length direction of the channel 3) of the end portion of the extraction electrode 51 on the thin substrate 11 and 21 side is a, and the extraction electrode 51 When the width dimension (dimension in the direction orthogonal to the length direction of the channel 3) on the side connected to the electrode 81 at the end is defined as b, it is desirable that a / b satisfy 1.1 to 5.

  As described above, when the shape of the extraction electrode 51 is set to such a shape, peeling of the extraction electrode 51 can be prevented in the lift-off process when the inkjet head is manufactured, and the substrate (thin substrate 11) can be prevented. , 21) while maintaining the adhesive force to the adjacent extraction electrodes 51, it is possible to prevent electrical short-circuit between the adjacent extraction electrodes 51. As a result of the improvement in the electrical conductivity and adhesion, variations in ink ejection for each channel. Can be reduced.

  Each above-mentioned embodiment is an example of the present invention, and the present invention is not limited to each embodiment. In addition, various modifications can be made depending on the design or the like as long as the technical idea of the present invention is not deviated.

1 is a perspective view showing the configuration of a first embodiment of an inkjet head according to the present invention. 1 is a cross-sectional view showing a configuration of a first embodiment of an inkjet head according to the present invention. FIG. 3 is a top view illustrating a relationship between the first substrate and the driver substrate in the first embodiment of the inkjet head according to the invention. Sectional drawing which shows the manufacturing process in 1st Embodiment of the inkjet head which concerns on this invention. FIG. 6 is a top view showing another structure of the extraction electrode in the first embodiment of the inkjet head according to the present invention. Sectional drawing which shows the structure of the extraction electrode in 2nd Embodiment of the inkjet head which concerns on this invention. The perspective view which shows the structure of the extraction electrode in 2nd Embodiment of the inkjet head which concerns on this invention. The perspective view which shows the structure in 3rd Embodiment of the inkjet head which concerns on this invention. The perspective view which shows the structure of the conventional inkjet head. Sectional drawing which shows the structure of the channel of the conventional inkjet head. Sectional drawing which shows the structure of the taking-out electrode of the conventional inkjet head. The perspective view which shows the structure of the taking-out electrode of the conventional inkjet head.

Explanation of symbols

2 Cover member 3 Channel 4 Partition 5 Electrode 6 Nozzle plate 7 Ink supply port 8 Driver substrate 10 First substrate 11 Thin substrate 12 Thick substrate 20 Second substrate 21 Thin substrate 22 Thick substrate 51 Extraction electrode 81 Electrode

Claims (6)

A plurality of channels for storing ink are provided by forming a plurality of partition walls at predetermined intervals on a substrate made of a piezoelectric material, and a nozzle for ejecting ink is provided at one end thereof, along each of the channels. An ink jet formed so that an electrode is provided, the electrode is extended in the direction of the other end of the substrate, a takeout electrode is provided, and the takeout electrode is connected to an electrode of a driver substrate to receive a voltage supply In the head
An ink jet head characterized in that the shape of the end of the extraction electrode is an arc. 2. The ink jet head according to claim 1, wherein the end portion of the extraction electrode has an arcuate contact surface with the substrate when formed on the substrate. 2. The inkjet head according to claim 1, wherein a shape of an end portion of the extraction electrode is an arc shape on an installation surface installed on the substrate. The inkjet head according to claim 1, wherein the shape of the end portion of the extraction electrode is symmetrical with respect to the length direction of the channel. The inkjet head according to any one of claims 1 to 3, wherein a shape of an end portion of the extraction electrode is a semicircular shape. The cross-sectional shape in the direction orthogonal to the length direction of the channel of the extraction electrode is a shape in which the width dimension on the side installed on the substrate is larger than the width dimension on the side connected to the electrode of the driver substrate The inkjet head according to any one of claims 1 to 5, wherein

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