JP4192298B2 - Inkjet head manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet head that records characters and figures by ejecting ink from nozzle holes and a method for manufacturing the same.
[0002]
[Prior art]
Ink jet heads are usually ejected grooves communicating with nozzle holes, and the ink is removed from the nozzle holes by applying pressure to the ink by deforming the piezoelectric material or locally heating and vaporizing the ink. It is comprised so that it may inject.
[0003]
Conventionally, as an inkjet head using a piezoelectric material, a plurality of grooves parallel to the upper surface of the actuator substrate made of a piezoelectric material and a plurality of connection terminals on the back surface are selectively provided from each connection terminal to an electrode on each side surface of each groove. In some cases, a voltage is applied to the electrode to deform the partition between the grooves. When manufacturing such an ink jet head, first, a plurality of grooves are formed in parallel on the upper surface of the actuator substrate made of a piezoelectric material, and then the entire surface of the actuator substrate including the inside of the grooves is electrically conductive by electroless plating or the like. Form a layer. Then, by dividing the conductive layer into grooves by grinding or laser processing, an electrode made of a conductive layer is formed on the partition walls of each groove, and the conductive layer on the back surface is divided from the front end surface of the actuator substrate. By doing so, a plurality of connection terminals individually connected to the electrodes of the respective grooves are formed. Then, by connecting a wiring material such as a flexible printed wiring board to the connection terminal, the flexible printed wiring board is connected to the drive control unit of the inkjet recording apparatus and the drive voltage output from the drive control unit based on the recording data. Then, the ink is applied to each partition wall via each connection terminal to be deformed, and the ink in each groove is ejected from the nozzle hole.
[0004]
[Problems to be solved by the invention]
In a conventional inkjet head, a nickel layer as a conductive layer is formed on the entire surface of an actuator substrate made of piezoelectric material by electroless plating, etc., and gold is coated on the nickel layer by electrolytic plating, and further insulated on the nickel layer. The protective film is formed by spin coating or CVD. This is because it is difficult to braze the wiring material to nickel, so that the brazing property is improved by interposing gold. Nickel itself has high corrosion resistance to ink. However, if gold is placed on nickel, nickel is easily ionized and comes into contact with the ink. When the ink comes into contact with the nickel through the gap, the ink is easily corroded, so that it is covered with an insulating protective film.
[0005]
Further, in the conventional manufacturing method, since the plurality of connection terminals are formed by dividing the conductive layer by irradiating the actuator substrate with laser light, the conductive components to be removed during the division processing are scattered and each connection terminal Adhere to. Therefore, the scattered conductive component reduces the insulation between the connection terminals, and the connection terminals are contaminated, and the wiring material such as the flexible printed wiring board cannot be brazed with high strength. Further, in the process up to the brazing process, brazing with high strength may not be achieved due to residual components of organic or inorganic foreign matters adhering to the brazing surface.
[0006]
The present invention solves this problem, and improves the brazing strength of the wiring material to the connection terminals, and can ensure the corrosion resistance of the electrodes to the ink and the insulation between the connection terminals, and the manufacture thereof Provide a method.
[0007]
[Means for Solving the Problems and Effects of the Invention]
In order to solve the above problem, an inkjet head manufacturing method according to claim 1 is an actuator substrate, a plurality of ejection grooves for ejecting ink formed on one surface of the actuator substrate, and the plurality of ejection grooves. A plurality of electrodes for applying ejection energy to the ink in the ejection grooves, and disposed on a surface opposite to the plurality of ejection grooves of the actuator substrate. An inkjet head manufacturing method comprising: a plurality of connection terminals connected to electrodes; and a wiring material brazed to the connection terminals, wherein the actuator substrate includes a plurality of inks including the plurality of ejection grooves. A step of forming a passage, a step of forming a conductive layer on the actuator substrate on which the plurality of ink passages are formed, and a first lens attached. A step of dividing the conductive layer by performing laser processing using a laser processing apparatus to form the electrode and the connection terminal corresponding to each ink passage, and the first lens is made to be more than the first lens. And performing a laser processing using the laser processing apparatus replaced with the second lens having a low light collection rate, thereby performing an etching process on a portion of the conductive layer corresponding to the connection terminal.
[0008]
Thereby, the residual component of the organic or inorganic foreign material of the part to braze in a connection terminal can be removed, and a connection terminal and wiring material can be brazed firmly. When the conductive layer is formed on a plurality of connection terminals by split processing, even if the conductive component scatters to the surroundings, the scattered conductive component is removed by etching, and the electrical insulation between the connection terminals is improved. Can be secured.
Further, in this manufacturing method, by forming a conductive layer interconnected to the actuator substrate comprising an injection groove, after which, divided into portions corresponding to the connecting terminal and each injection groove, corresponding to the connection pin By performing the etching process on the portion, the reliability of mutual connection between the plurality of electrodes and the connection terminal can be increased, and it can be easily manufactured.
[0009]
Preferably, as described in claim 2, the plurality of electrodes and the plurality of connection terminals are made of a conductive material having high corrosion resistance against one continuous ink. That is, with a simple configuration made of one material, the corrosion resistance to the ink and the above-described brazing property can be achieved at the same time. In particular, in this case, as described in claim 3, it can be easily formed on the actuator substrate by plating, vapor deposition or the like.
[0010]
Further, according to a fourth aspect of the present invention, the actuator substrate has a structure in which at least both sides of each of the injection grooves are formed of a partition made of a piezoelectric material polarized at least partially, and the electrode is formed on a side surface of the partition. In this case, a continuous conductive material layer can be formed from the ejection groove to the back surface of the actuator substrate opposite to the ejection groove, which facilitates manufacture.
[0011]
[0012]
[0013]
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
The ink-jet head has an actuator substrate 1, a plate member 4, a nozzle plate 6, and a manifold member 7. The actuator substrate 1 is configured by laminating a plurality of piezoelectric materials made of ceramics such as lead zirconate titanate (PZT) or lead titanate (PT), and the piezoelectric materials of the respective layers are in opposite directions ( Each is polarized in the direction of the thickness of the actuator substrate 1 (arrow 27 in FIG. 1). A plurality of grooves 14 and 15 are formed on the upper surface of the actuator substrate 1 by cutting over each layer. Of the plurality of grooves, every other groove is used as an ejection groove 14 for ejecting ink, and every other groove between both ends and the ejection groove 14 is used as a dummy groove 15.
[0016]
Each injection groove 14 is formed through the actuator substrate 1 from the front end 1a (left end in the figure) to the rear end 1d (right end in the figure) at a predetermined depth. Each dummy groove 15 is formed to have a predetermined depth from the front end of the actuator substrate 1 to the vicinity of the rear end side, and the rear end portion of the dummy groove is raised so as to be flush with the upper surface of the actuator substrate 1. Has been blocked. Further, a longitudinal groove 40 is formed at a position corresponding to the dummy groove 15 at the tip of the actuator substrate 1. The injection grooves 14 and the dummy grooves 15 are alternately arranged in parallel via the actuator partition walls 20, and the actuator partition walls 20 are composed of a plurality of layers of piezoelectric materials polarized in opposite directions.
[0017]
A conductive layer 41 of Ni (nickel) is formed by vapor deposition or electroless plating on the entire surface of the actuator substrate 1 including each injection groove 14, each dummy groove 15, the rear end surface 1d, and the back surface 1c. The front end surface 1a and the upper surface 1b of the actuator substrate 1 are cut or ground into a planar shape to remove the conductive layer. In the center of the bottom surface of each dummy groove 15, a first dividing groove 44 a is formed from the front end side to the surface without the conductive layer on the rear end upper surface. As a result, one electrode 23 is formed on the inner surface of each injection groove 14, and two independent electrodes 22, 22 are formed on the inner surface of each dummy groove 15. Each vertical groove 40 communicating with the dummy groove 15 is formed with a second divided groove 44b that is continuous with the first divided groove 44a. Furthermore, on the back surface 1c of the actuator substrate 1, as shown in FIG. 2, a plurality of third divided grooves 44c connected to the second divided grooves 44a are parallel to the dummy grooves 15 from the front end side to the vicinity of the rear end. A fourth divided groove 44d is formed on the rear end side of each third divided groove 44c so as to be orthogonal to the third divided groove 44c.
[0018]
Thus, each of the divided grooves 44c to 44d has a plurality of connection terminals 43 formed in parallel on the back surface of the actuator substrate 1, and a connection terminal 46 on the common potential side formed around the connection terminals 43. The connecting groove 43 is connected to the electrodes 22 and 22 on the side of the dummy grooves 15 of the two actuator partitions 20 with the vertical grooves 40. The injection grooves 14 and the two actuator partitions 20 adjacent to each other are used as a set of actuators. They are electrically connected to each other via the inner conductive layer 41, and are separated and independent from other sets of actuators by dividing grooves 44a to 44c. The connection terminal 46 on the common potential side is connected to the electrode 23 in the ejection groove 14 via the conductive layer 41 on the actuator substrate 1 rear end face 1d.
[0019]
Further, as shown in FIG. 2, a wiring material, that is, a flexible printed wiring board 32 is connected to the back surface 1c of the actuator substrate 1 on which the connection terminals 43 and 46 are formed by brazing (for example, soldering). The connection terminals 43 and 46 are provided with an etched brazing surface 49, and terminals 64 and 67 are formed on the flexible printed wiring board 32 corresponding to the brazing surface 49. The terminals 64 and 67 are connected to a drive control unit of an inkjet recording apparatus (not shown).
[0020]
On the upper surface of the actuator substrate 1 configured as described above, a flat plate member 4 made of a ceramic material or a resin material is bonded in a liquid-tight state with an epoxy-based adhesive or the like. Thus, each injection groove 14 is covered with the plate member 4 to open only the front end and the rear end. Each dummy groove 15 is covered with the plate member 4 so that only the tip is opened.
[0021]
A nozzle plate 6 is joined to the tips of the actuator substrate 1 and the plate member 4 in a liquid-tight state using an epoxy adhesive or the like. In the nozzle plate 6, a plurality of nozzle holes 30 are formed corresponding to each ejection groove 14 so that ink droplets are ejected from the ejection grooves 14.
[0022]
A manifold member 7 is joined to the rear ends of the actuator substrate 1 and the plate member 4. An ink supply port 31 connected to an ink tank (not shown) is formed at the center of the manifold member 7 and distributes ink to all the ejection grooves 14.
[0023]
FIG. 6 shows a processing apparatus for forming the divided grooves 44a to 44c, for example, a laser processing apparatus such as a YAG laser. The laser processing apparatus includes a laser oscillator 81 that emits laser light 82, an X-axis galvanometer 84 that includes a reflecting mirror 83 that reflects the laser light and scans it in the X-axis direction (groove arrangement direction), and laser light 82. A Y-axis galvanometer 86 having a reflecting mirror 85 that reflects and scans in the Y-axis direction (longitudinal direction of the groove) and a condensing lens 87 that emits laser light 82 are provided. Then, the laser beam 82 is scanned and irradiated along the conductive layer, so that the conductive layer is linearly removed to form the respective divided grooves 44a to 44d.
[0024]
Next, a method for manufacturing the ink jet head will be described.
[0025]
First, the actuator substrate 1 is formed by slicing a flat plate made of laminated piezoelectric material into a strip shape, and then a plurality of injection grooves 14, dummy grooves 15, and vertical grooves 40 are formed by a diamond blade or the like. Thereafter, a conductive layer 41 of Ni or the like is formed on the entire surface including the grooves 14, 15, 40 of the actuator substrate 1 by vapor deposition or electroless plating. After that, the upper surface 1b of the actuator substrate 1 is cut or ground into a planar shape to remove the conductive layer on the upper surface, and the conductive layers in the grooves 14, 15 are made independent on the upper surface.
[0026]
As shown in FIG. 6, the actuator substrate 1 is mounted below the laser processing apparatus 80, and the conductive layer 41 is divided. First, the first divided groove 44a is formed by scanning the bottom surface of the dummy groove 15 and removing the conductive layer in a linear shape. The same processing is sequentially performed on the bottom surface of the adjacent dummy groove 15. Similarly, the bottom surface of the vertical groove 40 is scanned to remove the conductive layer in the form of a line to form the second divided groove 44b. Further, the back surface 1c of the actuator substrate 1 is also irradiated with the laser beam 82 to remove the conductive layer in a linear form, thereby forming third and fourth divided grooves 44c and 44d. By forming the first to fourth dividing grooves 44a to 44d in this division processing, and cutting or grinding the upper surface 1b and the front end surface 1a of the actuator substrate 1 (processing of the front end surface will be described later), the conductive layer 41 becomes each actuator. Every time, it is made independent in the dummy groove 15 on the back surface 1c.
[0027]
Next, the plate member 4 is joined to the upper surface of the actuator substrate 1, and the tip surfaces of the actuator substrate 1 and the plate member 4 are cut or ground into a flat surface, and the conductive layer 41 on the tip surface 1 a is removed. To do.
[0028]
An etching process is performed on each brazing surface 49 of the connection terminals 43 and 46 formed on the back surface of the actuator substrate 1. This etching process is performed by removing the conductive components scattered and adhered when the connection terminals 43 and 46 are laser-processed as described above and the residual components of organic or inorganic foreign matters adhering to the previous steps. This ensures insulation between the terminals 43 and 46 and improves brazing.
[0029]
FIG. 7 shows a laser processing apparatus for performing an etching process, a laser oscillator 71 for emitting a laser beam 72, a reflecting mirror 73 for reflecting the laser beam 72 toward the actuator substrate 1, and an image with a low light collection rate. And an imaging lens 74 that irradiates the actuator substrate 1 with the laser beam 72. 55 is a laser control device, and 56 is a stage control device for positioning stages 51 and 52 on which the actuator substrate 1 is mounted, and controls irradiation of the laser beam 72 and movement of the positioning stages 51 and 52 based on a preset program. To do. When etching the back surface of the actuator substrate 1, as shown in FIG. 8, the actuator substrate 1 is arranged on the positioning stages 51 and 52 in the vacuum chamber 77, and the etching gas sprayed from the gas nozzle 78 is used as the actuator substrate. This is performed by irradiating the imaging laser beam 72 from the optical window 76 of the vacuum chamber 77 while spraying on the back surface of 1. In addition, it is preferable to use an excimer laser as the laser beam 72 irradiated to the actuator substrate 1, and when the imaging laser beam 72 in the ultraviolet region by the excimer laser is irradiated, the conductive component and the residual component of the foreign matter are changed from the etching gas. Since the physical properties are changed by the chemical change and the intermolecular bonding force is reduced, it is possible to efficiently perform the etching process by cutting off the intermolecular bonding force by the excimer laser.
[0030]
In the above description, the laser processing apparatus for forming each of the divided grooves 44a to 44d and the laser processing apparatus for performing the etching process are individually described. However, the present invention is not limited to this. That is, the etching process may be commonly performed by a laser processing apparatus that forms each of the divided grooves 44a to 44d. In this case, in order to perform the etching process with the latter laser processing apparatus, it can be applied by using the imaging lens 74 instead of the condensing lens 87, and the laser beam 85 for forming the divided grooves 44a to 44d is etched. By sharing it with each other, the equipment cost can be reduced.
[0031]
The etching process can also be performed by a plasma process. For example, in the case of a parallel plate type as shown in FIG. 9, the plasma processing apparatus includes a vacuum chamber 110, an electrode 130 and a sample holder 120 facing vertically. The electrode 130 is grounded, and RF power is applied to the sample holder 12. The inside of the vacuum chamber is decompressed by a vacuum pump through an exhaust pipe 150, and Ar gas is supplied through a gas supply pipe 140.
[0032]
When RF power is applied to the sample holder 120, the Ar gas becomes plasma containing ions and electrons. On the other hand, the sample holder 120 is self-biased, and ions in the plasma are attracted to the sample holder 120 and accelerated. Then, the conductive layer on the back surface of the actuator substrate 1 placed on the sample holder 120 is physically etched by the accelerated ions. Thereby, the scattered conductive component and the residual component of the foreign matter are removed.
[0033]
Plasma devices other than those described above, for example, barrel type devices can also be used.
[0034]
Then, the nozzle plate 6 is joined to the front end face and the manifold member 7 is joined to the rear end face so that the injection groove 14 and the nozzle hole 30 correspond to each other. Thereafter, the flexible printed wiring board 32 and the connection terminals 43 and 46 of the actuator substrate 1 are connected. In this connection, the terminals 64 and 67 of the flexible printed circuit board 32 are brought into contact with the brazing surfaces 49 of the connection terminals 43 and 46 of the actuator substrate 1 and then brazed (for example, soldered). To be assembled as an inkjet head. Note that a solder layer is formed in advance on each of the terminals 64 and 67 of the flexible printed circuit board 32 and is melted by heating and fixed to the connection terminals 43 and 46.
[0035]
Thus, according to the ink jet head of this embodiment, the drive signal output through the flexible printed wiring board 32 from the drive control unit of the ink jet recording apparatus (not shown) is applied to the pair of electrodes 22 and 22 of each actuator, By grounding the electrode 23, an electric field perpendicular to the polarization direction 27 is generated in the pair of partition walls 20, and the partition walls 20 are deformed to eject the ink in the ejection grooves 14.
[0036]
The electrode 23 formed in the ejection groove 14 and the connection terminals 43 and 46 on the back surface 1c of the actuator substrate 1 are made of Ni, and Ni itself has high corrosion resistance against ink. Further, since the connection terminals 43 and 46 are etched as described above and have good brazing properties, the terminals 64 and 67 of the flexible printed wiring board 32 are well bonded. Thus, in order to improve the brazing property to the connection terminals 43 and 46, an Au (gold) conductive layer is formed on Ni, or an insulating protective film is formed to increase the corrosion resistance against ink. Although it can be omitted originally, it does not prevent them from being used together.
[0037]
In the present invention, as the conductive layer, not only Ni but also other materials having high corrosion resistance against ink can be used. Further, the present invention can be applied not only to ejecting ink by deforming the partition wall of the ejection groove 14 but also to other types of heads that supply power to the actuator for ink ejection through the connection terminals 43 and 46. it can.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an inkjet head as viewed from above.
FIG. 2 is an exploded perspective view of the inkjet head as viewed from below.
3 is an enlarged view in which a part of the ink jet head of FIG. 2 is sectioned in a groove row direction.
4 is a cross-sectional view taken along line AA in FIG.
5 is a cross-sectional view taken along line BB in FIG.
FIG. 6 is an explanatory diagram showing a state in which a division groove is formed by a laser processing apparatus.
FIG. 7 is an explanatory view showing a state in which an etching process is performed by a laser processing apparatus.
FIG. 8 is an explanatory diagram showing a state in which an etching process is performed by a laser processing apparatus.
FIG. 9 is an explanatory diagram showing a state in which an etching process is performed by a plasma processing apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Actuator board | substrate 14 Injection groove | channel 15 Dummy groove | channel 20 Actuator partition wall 22 Electrode 23 Electrode 32 Wiring material 41 Ni conductive layer 43 Connection terminal 46 Connection terminal 49 Brazing surface

Claims (4)

  An actuator substrate;
  A plurality of ejection grooves formed on one surface of the actuator substrate for ejecting ink;
  A plurality of electrodes that are disposed so as to be exposed in the plurality of ejection grooves, and that provide ejection energy to the ink in the ejection grooves;
  Arranged on the surface opposite to the plurality of ejection grooves of the actuator substrate, and provided with a plurality of connection terminals connected to the plurality of electrodes,
  A method of manufacturing an inkjet head, wherein a wiring material is brazed to the connection terminal,
  Forming a plurality of ink passages including the plurality of ejection grooves in the actuator substrate;
  Forming a conductive layer on the actuator substrate in which the plurality of ink passages are formed;
  Dividing the conductive layer by performing laser processing using a laser processing apparatus to which the first lens is attached, and forming the electrodes and the connection terminals corresponding to the respective ink paths;
  Etching is performed on a portion of the conductive layer corresponding to the connection terminal by performing laser processing using the laser processing apparatus in which the first lens is replaced with a second lens having a lower light collection rate than the first lens. And a step of
  A method for manufacturing an inkjet head. 2. The method of manufacturing an ink jet head according to claim 1, wherein the plurality of electrodes and the plurality of connection terminals are made of a conductive material having high corrosion resistance against one continuous ink. 3. The method of manufacturing an ink jet head according to claim 2, wherein the conductive material is formed on the actuator substrate by plating, vapor deposition or the like. The actuator substrate, the both sides of each injection grooves, at least partially constituted by partition walls of piezoelectric material is polarized, according to claim 3, characterized in that the formation of the plurality of electrodes on the side surfaces of the partition wall Manufacturing method of the inkjet head.

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