JPH11115196A - Ink jet head and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet head in which an electrode in an ejection groove has corrosion resistance to ink and has good brazing properties between a connection terminal and a wiring material, and a method for manufacturing the same. SOLUTION: A conductive layer made of Ni having good corrosion resistance to ink is formed on the entire surface of an actuator substrate having grooves 14 and 15 including a plurality of injection grooves, and the conductive layer is formed in the grooves by grinding and laser processing. Electrodes 22, 23,
It is divided into connection terminals 43 and 46. Form a brazing surface with good brazing properties by etching on the connection terminals,
A flexible printed wiring board 32 extending from an external drive control unit is connected by brazing.

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 for recording characters and figures by ejecting ink from nozzle holes, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Ink jet heads are generally formed by applying pressure to ink by deforming a piezoelectric material or locally heating and evaporating the ink in an ejection groove communicating with a nozzle hole. The ink is ejected from the nozzle holes.

Conventionally, an ink jet head using a piezoelectric material has a plurality of grooves parallel to the upper surface of an actuator substrate made of a piezoelectric material, and a plurality of connection terminals on the back surface. There is a type in which a voltage is selectively applied to the partition wall to deform the partition wall between the grooves. When manufacturing such an ink jet head, first,
After a plurality of grooves are formed in parallel on the upper surface of the actuator substrate made of a piezoelectric material, a conductive layer is formed by electroless plating or the like on the entire surface of the actuator substrate including the inside of the grooves. Then, the conductive layer is divided into individual grooves by grinding or laser processing to form electrodes made of the conductive layer on the partition walls of each groove, and is also divided from the front end surface of the actuator substrate to the conductive layer on the back surface. Thus, a plurality of connection terminals individually connected to the electrodes of each groove are formed. Then, by connecting a wiring material such as a flexible printed wiring board to the connection terminal, the drive voltage output from the drive control section based on the print data is connected to the drive control section of the ink jet printing apparatus, and the flexible printed wiring board is used. The ink is applied to each partition via each connection terminal and deformed, and the ink in each groove is ejected from the nozzle hole.

[0004]

In a conventional ink jet head, a nickel layer as a conductive layer is formed on the entire surface of an actuator substrate made of a piezoelectric material by electroless plating or the like, and gold is electrolytically plated on the nickel layer. And further apply an insulating protective film thereon by spin coating or CVD.
It is formed by a method or the like. 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, but if gold is placed on nickel, nickel is easily ionized and comes into contact with the ink. And the ink comes into contact with the nickel through the gap), and the ink tends to be corroded.

In the conventional manufacturing method, a plurality of connection terminals are formed by dividing the conductive layer by irradiating the actuator substrate with a laser beam, so that the conductive component to be removed during the division processing is scattered. Attaches to each connection terminal. Therefore, the insulating properties between the connection terminals are reduced by the scattered conductive components, and the connection terminals are contaminated, so that a wiring material such as a flexible printed wiring board cannot be brazed with high strength. Also, in the process up to the brazing step, brazing may not be performed with high strength due to residual components of organic or inorganic foreign matters attached to the brazing surface.

The present invention solves this problem, and improves the brazing strength of a wiring material to a connection terminal, and also ensures the corrosion resistance of an electrode to ink and the insulation between the connection terminals. And a method for producing the same.

[0007]

In order to solve the above problems, in the ink jet head according to the first aspect, a plurality of ejection grooves for ejecting ink to the actuator substrate, and a plurality of ejection grooves in each of the ejection grooves are provided. An ink jet head, comprising: a plurality of electrodes for applying ejection energy to ink; and a plurality of connection terminals connected to the respective electrodes at positions outside the respective ejection grooves, wherein the connection terminals are brazed to a wiring member. In the above, the portion where the wiring material is to be brazed is etched.

Thus, the residual components of the organic or inorganic foreign matter at the part to be brazed at the connection terminal are removed,
The connection terminal and the wiring member can be brazed firmly. In the case where the conductive layer is formed on a plurality of connection terminals by division processing, even if the conductive component scatters around, the scattered conductive component is removed by performing an etching process, thereby improving the electrical insulation between the connection terminals. Can be secured.

Preferably, the electrode is disposed so as to be exposed in each of the ejection grooves, and the electrode and the connection terminal have high corrosion resistance to one continuous ink. It is made of a conductive material. That is, 1
With a simple structure made of two materials, the corrosion resistance to the ink and the above-mentioned brazing properties are simultaneously achieved. In particular, in this case, it can be easily formed on the actuator substrate by plating, vapor deposition, or the like.

The actuator substrate may be configured such that at least both sides of each of the ejection grooves are formed of a partition wall of a piezoelectric material at least partially polarized, and the electrodes are formed on side surfaces of the partition wall. In the configuration in which the connection terminal is formed on the back surface of the actuator substrate on the side opposite to the ejection groove, a layer of a continuous conductive material can be formed from the ejection groove to the back surface of the actuator substrate on the opposite side, It is easy to manufacture.

According to a fifth aspect of the present invention, there is provided a method of manufacturing an ink jet head, comprising: a plurality of ejection grooves for ejecting ink to an actuator substrate; a plurality of electrodes for applying ejection energy to ink in each of the ejection grooves; A plurality of connection terminals connected to each of the electrodes at positions outside the groove, and a step of forming a plurality of ink passages in the actuator substrate in the ink jet head for brazing a wiring material to the connection terminals; Forming a conductive layer on the actuator substrate including a passage, dividing the conductive layer into a portion corresponding to the electrode and the connection terminal corresponding to each ink passage, and a portion corresponding to the connection terminal. Performing an etching process on the conductive layer.

In this manufacturing method, a conductive layer connected to each other is formed on the actuator substrate including the injection grooves, and then divided into portions corresponding to the respective injection grooves and the connection terminals, to correspond to the connection terminals. By performing the etching process on the portion, the reliability of mutual connection between the plurality of electrodes and the connection terminals can be increased and the device can be easily manufactured.

For example, the etching process is performed by laser light irradiation or plasma processing.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

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
It is formed 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 each layer are arranged in opposite directions (each of the actuator substrate 1). It is polarized in the thickness direction, as indicated by arrow 27 in FIG. On the upper surface of the actuator substrate 1, there are formed a plurality of grooves 14 and 15 which are cut through the respective layers. Of the plurality of grooves, every other groove is an ejection groove 14 for ejecting ink, and every other groove between both ends and the ejection groove 14 is a dummy groove 15.

Each injection groove 14 is formed to penetrate at a predetermined depth from the front end 1a (left end in the drawing) to the rear end 1d (right end in the drawing) of the actuator substrate 1. Each dummy groove 15
Are formed so as to have a predetermined depth from the front end to the vicinity of the rear end side of the actuator substrate 1, and the rear end of the dummy groove is raised and closed so as to be flush with the upper surface of the actuator substrate 1. ing. In addition, a vertical groove 40 is formed at a position corresponding to the dummy groove 15 at the tip of the actuator substrate 1. The ejection grooves 14 and the dummy grooves 15 are alternately arranged in parallel with the actuator partition wall 20 interposed therebetween. The actuator partition wall 20 is made of a plurality of layers of piezoelectric material polarized in opposite directions.

A conductive layer 41 of Ni (nickel) is formed on the entire surface of the actuator substrate 1 including the injection grooves 14, the dummy grooves 15, the rear end surface 1d, and the back surface 1c by vapor deposition or electroless plating. Tip surface 1 of actuator substrate 1
The conductive layer is removed from a and the upper surface 1b by cutting or grinding into a planar shape. Then, each dummy groove 15
In the center of the bottom surface, a first division groove 44a is formed from the front end side to the rear end upper surface without the conductive layer. As a result, one electrode 23 is formed on the inner surface of each injection groove 14, and 2 electrodes are formed on the inner surface of each dummy groove 15.
Two independent electrodes 22, 22 are formed. Each vertical groove 40 communicating with the dummy groove 15 has a first divided groove 44.
A second dividing groove 44b that is continuous with a is formed. Further, on the back surface 1c of the actuator substrate 1, as shown in FIG. 2, a plurality of third divided grooves 44c connected to each of the second divided grooves 44a are arranged in parallel with each dummy groove 15 from the front end side to the vicinity of the rear end. The 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.
Are formed.

Thus, each of the divided grooves 44c to 44d is
A plurality of connection terminals 43 are formed in parallel on the back surface of the actuator substrate 1 and connection terminals 46 on the common potential side are formed therearound.
Is formed. The connection terminal 43 is connected to the electrodes 22 on the dummy groove 15 side of the actuator groove 20 and the vertical groove 4 by using the injection groove 14 and two actuator partition walls 20 sandwiching the injection groove 14 as one set of actuators.
0 are electrically connected via a conductive layer 41 in
It is separated and independent from the other sets of actuators by the divided grooves 44a to 44c. 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 rear end face 1d of the actuator substrate 1.

Further, as shown in FIG.
Back surface 1c of actuator substrate 1 on which 3, 46 are formed
, A wiring material, that is, a flexible printed wiring board 32 is connected by brazing (for example, soldering). The connection terminals 43 and 46 are provided with an etched brazing surface 49, and the 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 (not shown) of the ink jet recording apparatus.

A flat plate member 4 made of a ceramic material or a resin material is joined to the upper surface of the actuator substrate 1 configured as described above in a liquid-tight manner by an epoxy adhesive or the like. Thereby, each injection groove 14
Is covered with the plate member 4 to open only the front end and the rear end. In addition, each dummy groove 15 is opened only at the tip by being covered with the plate member 4.

A nozzle plate 6 is joined to the distal ends of the actuator substrate 1 and the plate member 4 in a liquid-tight manner using an epoxy-based adhesive or the like. In order to eject ink droplets from the ejection grooves 14 to the nozzle plate 6,
A plurality of nozzle holes 30 are formed corresponding to each injection groove 14.

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.

FIG. 6 shows a processing apparatus for forming each of 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 a laser beam 82; an X-axis galvanometer 84 having a reflecting mirror 83 that reflects the laser beam and scans the laser beam in the X-axis direction (the direction in which the grooves are arranged); A Y-axis galvanometer 86 having a reflecting mirror 85 for reflecting and scanning in the Y-axis direction (longitudinal direction of the groove), and a condenser lens 87 for emitting a laser beam 82 are provided. Then, the laser light 82
Is scanned and irradiated along the conductive layer, so that the conductive layer is linearly removed to form the divided grooves 44a to 44d.

Next, a method of manufacturing the ink jet head will be described.

First, an actuator substrate 1 is formed by slicing a flat plate made of a 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. I do.
Thereafter, each groove 14, 15, 40 of the actuator substrate 1 is formed.
A conductive layer 41 of Ni or the like is formed by vapor deposition or electroless plating on the entire surface including. After that, the conductive layer on the upper surface 1b of the actuator substrate 1 is removed by cutting or grinding the upper surface 1b into a planar shape, and the conductive layers in the grooves 14 and 15 are made independent on the upper surface.

The actuator substrate 1 is mounted below the laser processing device 80 as shown in FIG. 6, and the conductive layer 41 is divided. First, the bottom surface of the dummy groove 15 is scanned and the conductive layer is linearly removed to form the first divided groove 44a. The same processing is sequentially performed on the bottom surface of the adjacent dummy groove 15. The conductive layer is linearly removed by scanning the bottom surface of the vertical groove 40 in the same manner 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 linearly,
Third and fourth division grooves 44c and 44d are formed. Formation of the first to fourth division grooves 44a to 44d in this division processing;
By 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 is made independent in the dummy groove 15 and on the back surface 1c for each actuator.

Next, the plate member 4 is joined to the upper surface of the actuator substrate 1, and the distal end surfaces of the actuator substrate 1 and the plate member 4 are cut or ground into a planar shape, and the conductive layer on the distal end surface 1a is formed. 41 is removed.

An etching process is performed on the brazing surfaces 49 of the connection terminals 43 and 46 formed on the back surface of the actuator substrate 1. In this etching process, when the connection terminals 43 and 46 are laser-processed as described above, the conductive components that are scattered and adhered and the residual components of organic or inorganic foreign substances that have adhered in the previous steps are removed. Terminal 4
It is intended to secure insulation between 3, 46 and improve brazing properties.

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 a low focusing rate. Lens 7 for irradiating the actuator substrate 1 with the laser beam 72 formed on the substrate
4 is provided. 55, a laser controller; 56, a positioning stage 51 on which the actuator substrate 1 is mounted;
A stage controller 52 controls irradiation of the laser beam 72 and movement of the positioning stages 51 and 52 based on a preset program. When etching the back surface of the actuator substrate 1, as shown in FIG.
The actuator substrate 1 is arranged on the positioning stages 51 and 52 in the vacuum chamber 77, and the imaging laser beam 72 is emitted from the optical window 76 of the vacuum chamber 77 while blowing the etching gas sprayed from the gas nozzle 78 onto the back surface of the actuator substrate 1. Irradiation is performed. It is preferable to use an excimer laser as the laser light 72 applied to the actuator substrate 1. When the imaging laser light 72 in the ultraviolet region is applied by the excimer laser, a conductive component and a residual component of a foreign substance are mixed with the etching gas. Because physical properties are changed by chemical change and intermolecular bonding force is reduced,
Processing for etching by cutting off intermolecular bonding force by excimer laser can be efficiently performed.

In the above description, each of the divided grooves 44a to 44a
Although the laser processing device for forming 4d and the laser processing device for performing the etching process are individually provided, the present invention is not limited to this. That is, the etching process may be commonly performed by a laser processing apparatus that forms the divided grooves 44a to 44d. In this case, in order to perform the etching process with the latter laser processing apparatus, it is possible to use the imaging lens 74 instead of the condensing lens 87, and the laser beam 85 that forms each of the divided grooves 44a to 44d is subjected to the etching process. By sharing to
Equipment costs can be reduced.

The etching process can be performed by a plasma process. For example, in the case of a parallel plate type plasma processing apparatus as shown in FIG.
0, and an electrode 130 and a sample holder 120 which are opposed to each other vertically. The electrode 130 is grounded, and RF power is applied to the sample holder 12. The pressure inside the vacuum chamber is reduced by a vacuum pump through an exhaust pipe 150, and Ar gas is supplied through a gas supply pipe 140.

When RF power is applied to the sample holder 120, the Ar gas becomes a plasma containing ions and electrons.
On the other hand, the sample holder 120 has a self-bias, and the ions in the plasma are attracted to the sample holder 120 and accelerated. Then, the sample holder 120
The conductive layer on the back surface of the actuator substrate 1 mounted thereon is physically etched by the accelerated ions. Thereby, the scattered conductive components and residual components of the foreign matter are removed.

A plasma device other than the above-mentioned system, for example, a barrel type can be used.

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 board 1 are connected. This connection is made by the terminals 64, 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 connected by brazing (for example, soldering) to assemble as an ink jet head. The terminals 64 and 67 of the flexible printed wiring board 32 are each formed with a solder layer in advance, melted by heating and fixed to the connection terminals 43 and 46.

As described above, according to the ink jet head of the present embodiment, the drive signal output from the drive control unit of the ink jet recording apparatus (not shown) through the flexible printed wiring board 32 is applied to the pair of electrodes 22 of each actuator. By applying the voltage and grounding the electrode 23, an electric field is generated in the pair of partition walls 20 in a direction perpendicular to the polarization direction 27, and the partition walls 20 are deformed to eject ink in the ejection grooves 14. I have.

The electrode 23 formed in the injection groove 14 and the connection terminals 43 and 46 on the back surface 1c of the actuator substrate 1
Is composed of Ni, and Ni itself has high corrosion resistance to 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 satisfactorily joined. Accordingly, forming a conductive layer of Au (gold) on Ni in order to improve brazing properties to the connection terminals 43 and 46, and forming an insulating protective film in order to increase corrosion resistance to ink, Although they can be omitted altogether, they do not prevent their use in combination.

In the present invention, not only Ni but also a material having high corrosion resistance to ink can be used as the conductive layer. Further, the present invention can be applied not only to a type in which the partition of the ejection groove 14 is deformed to eject ink, but also to a type in which power is supplied to an actuator for ink ejection through the connection terminals 43 and 46 in other types of heads. 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.

FIG. 3 is an enlarged view of a part of the inkjet head of FIG. 2 in a cross section in a groove row direction.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a sectional view taken along line BB of FIG. 3;

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 where an etching process is performed by a laser processing apparatus.

FIG. 8 is an explanatory view showing a state where an etching process is performed by a laser processing apparatus.

FIG. 9 is an explanatory view showing a state where an etching process is performed by the plasma processing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Actuator board 14 Injection groove 15 Dummy groove 20 Actuator partition 22 Electrode 23 Electrode 32 Wiring material 41 Ni conductive layer 43 Connection terminal 46 Connection terminal 49 Brazing surface

Claims (6)

[Claims] 1. A plurality of ejection grooves for ejecting ink to an actuator substrate, a plurality of electrodes for applying ejection energy to ink in each of the ejection grooves, and a plurality of electrodes at positions outside the respective ejection grooves. With a plurality of connected terminals,
An ink jet head for brazing a wiring material to the connection terminal, wherein a portion of the connection terminal to which the wiring material is brazed is subjected to an etching process. 2. The electrode is disposed so as to be exposed in each of the ejection grooves, and the electrode and the connection terminal are made of a conductive material having high corrosion resistance to one continuous ink. The inkjet head according to claim 1, wherein 3. The ink jet head according to claim 2, wherein the conductive material is formed on the actuator substrate by plating, vapor deposition, or the like. 4. The actuator substrate, wherein both sides of each of the ejection grooves are formed of a partition wall of a piezoelectric material at least partially polarized, the electrodes are formed on side surfaces of the partition wall, and the connection terminals are formed on the side surfaces of the partition wall. 4. The ink jet head according to claim 3, wherein the ink jet head is formed on the surface of the actuator substrate opposite to the ink passage. 5. A plurality of ejection grooves for ejecting ink to an actuator substrate, a plurality of electrodes for applying ejection energy to ink in each of the ejection grooves, and a plurality of electrodes at positions outside the respective ejection grooves. With a plurality of connected terminals,
In the inkjet head for brazing a wiring material to the connection terminal, a step of forming a plurality of ink paths in the actuator substrate; a step of forming a conductive layer on the actuator substrate including the ink path; A method for manufacturing an ink jet head, comprising: a step of dividing the electrode corresponding to each ink passage and a portion corresponding to the connection terminal; and a step of performing an etching process on a conductive layer in a portion corresponding to the connection terminal. 6. The method according to claim 5, wherein the etching is performed by laser light irradiation or plasma processing.