JP3311514B2 - Ink jet head and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head and a method for manufacturing the same, and more particularly to an on-demand type ink jet head.

[0002]

2. Description of the Related Art The ink jet recording system has attracted attention because it can record without contacting a head on recording paper, and has a very simple recording process and is suitable for color recording. Conventionally, various methods have been proposed as the ink jet recording method, but at present, the so-called drop-on-demand (DOD) method in which ink is ejected only when a recording signal is input has become mainstream. The DOD method includes a so-called bubble jet method and a piezo actuator method.

The former bubble jet method utilizes bubbles generated in ink by thermal energy. For example, as described in Japanese Patent Publication No. 61-59913, an equivalent of an actuator is provided in an ink flow path. In this method, a bubble is generated on the surface of the heater by directly and instantaneously heating the ink with the heater, and the ink is turned into droplets by the pressure increase in the ink flow path at this time to fly from the nozzle. . In this method, the energization time for heating the heater is 5 to 10 μsec, and the surface temperature of the heater reaches 300 ° C.

The bubble jet method has the advantage that the heater corresponding to the actuator is very small and the head is highly integrated and easy to miniaturize. On the other hand, since the heater raises the substrate temperature, it is repeatedly driven. There are drawbacks that the frequency cannot be too high, and that the type of ink that can be used is limited because the ink is directly heated by the heater.

On the other hand, in the latter piezo actuator system, as described in Japanese Patent Publication No. 60-8953, for example, a nozzle is formed on a wall surface of a container forming a liquid chamber, and the nozzle is opposed to the nozzle. Then, a piezoelectric element is disposed in the liquid chamber, and by driving the piezoelectric element, a dynamic pressure is generated in the nozzle area, so that the ink is formed into droplets and fly from the nozzles (hereinafter, referred to as a “first method”). ) And, for example, as described in JP-A-3-10846,
As a structure in which the wall constituting the pressurized liquid chamber is deformable, a piezoelectric element is provided outside the deformable wall, and the wall of the pressurized liquid chamber is deformed by using the piezoelectric element to change its internal volume. Thus, there is a method (hereinafter, referred to as “second method”) in which ink is given pressure to form droplets and fly from nozzles. This piezo actuator method requires a pulse-like pressure increase in the nozzle area or the pressurized liquid chamber in front of the piezoelectric element, and the voltage waveform applied to the piezoelectric element is several μsec.
The rise time is set to about several tens of microseconds, and the supply of ink is performed by returning the displacement of the piezoelectric element.

In the first method in which a piezoelectric element is disposed in a liquid chamber in the piezo actuator method, the problem that the piezoelectric element directly contacts the ink is not solved, but the pressurized liquid chamber is formed. In the second method in which the deformable wall surface of the pressurized liquid chamber is deformed by the piezoelectric element, the piezoelectric element does not directly contact the ink, and furthermore, the heat generated by the piezoelectric element can be neglected. Although there is an advantage that there is no restriction on the kind of ink, it is difficult to increase the number of channels (here, “channel” means a portion composed of one piezoelectric element, a pressurized liquid chamber, and a nozzle). There are drawbacks.

Conventionally, in the second piezo actuator system, a multi-channel ink jet head is manufactured by sintering a green sheet made of a piezoelectric material as disclosed in, for example, Japanese Patent Application Laid-Open No. HEI 4-16353. A lower conductor layer is provided on a lower piezoelectric element plate which is a substrate formed by forming an upper piezoelectric element plate serving as a driving piezoelectric element on the lower conductor layer, and further on the upper piezoelectric element plate. A laminate having an upper conductor layer is formed, and the laminate is cut at a depth from the upper conductor layer to the lower conductor layer to form two piezoelectric element plates having conductor layers on upper and lower surfaces. The piezoelectric element is divided into a plurality of piezoelectric elements by dividing the two piezoelectric element plates into a plurality of piezoelectric elements by cutting in a direction orthogonal to the cutting direction. The arranged two rows, the upper surface of the piezoelectric element array, that is, those disposed pressurized liquid chamber communicating with the nozzle to the upper conductive film top surface.

[0008]

By the way, as described above, in an ink jet head in which two piezoelectric element arrays each composed of a plurality of piezoelectric elements arranged on a substrate are arranged,
In order to apply a predetermined drive pulse between the electrodes of the individual piezoelectric elements, those electrodes must be connected to external common electrodes and individual driving electrodes. It becomes difficult.

In particular, as in the above-described conventional ink jet head, one piezoelectric element plate is divided into two piezoelectric element plates, and these two piezoelectric element plates are cut into individual piezoelectric elements. It is extremely difficult to connect an external electrode to each piezoelectric element, and when a laminated piezoelectric element is used as the piezoelectric element, the electrode connection work becomes more difficult.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and makes it easy to take out electrodes in a multi-channel (multi-nozzle) ink jet head, thereby simplifying an assembling process, improving production efficiency, and improving yield. The purpose is to:

[0011]

According to a first aspect of the present invention, there is provided an ink jet head comprising at least two rows of piezoelectric elements which are arranged at a predetermined pitch on a substrate. In the ink-jet head, end electrodes are respectively formed on both end faces of each of the piezoelectric elements of the two rows of the piezoelectric elements, and end electrodes on opposite end faces of each of the piezoelectric element rows are provided between the respective piezoelectric element rows on the substrate. Are connected to a common electrode provided on the substrate, and an end surface electrode on an end surface side of each piezoelectric element row that is not opposed is connected to an individual electrode provided on the substrate, and the individual electrode on this substrate is a row of the plurality of piezoelectric elements. Each piezoelectric element is independently divided by a dividing groove formed in a direction perpendicular to the setting direction.

According to a second aspect of the present invention, in the inkjet head of the first aspect, a common groove deeper than the dividing groove is formed between the piezoelectric element rows in a direction in which the plurality of piezoelectric elements are arranged on the substrate. The common electrode is formed in the common groove.

According to a third aspect of the present invention, in the method of manufacturing an ink jet head in which at least two rows of piezoelectric elements are arranged on a substrate, a pattern for an individual electrode is previously formed on the substrate. And
The two piezoelectric elements plates respectively forming the end face electrodes on both end surfaces independently in parallel on the substrate, and the piezoelectric element
After the two end face electrodes of the plates are joined to face each other, the two piezoelectric element plates and the individual electrode patterns on the substrate are simultaneously cut at a predetermined pitch, and the two piezoelectric element plates are respectively separated. At the same time as dividing into the plurality of piezoelectric elements constituting each piezoelectric element row, an individual electrode pattern on the substrate is divided into individual electrodes for each piezoelectric element.

According to a fourth aspect of the invention, in the method of the third aspect, the two piezoelectric element plates and the individual electrode patterns on the substrate are simultaneously cut at a predetermined pitch. Then, a conductive member serving as a common electrode connected to the end electrodes facing each piezoelectric element is bonded or coated between the two piezoelectric element rows.

According to a fifth aspect of the present invention, in the method of the third aspect, a common electrode pattern is previously formed on the substrate in a direction in which the plurality of piezoelectric elements are arranged. Configuration.

According to a sixth aspect of the present invention, in the method of manufacturing the ink jet head of the fifth aspect, a common groove having a depth which is not divided at the time of cutting the piezoelectric element plate is formed on the substrate in advance. The common electrode pattern is formed in the common groove.

According to a seventh aspect of the invention, there is provided a method of manufacturing an ink jet head according to any one of the third to sixth aspects, wherein each piezoelectric element plate is cut at a pitch twice as large as the nozzle pitch.

[0018]

According to a first aspect of the present invention, an end face electrode is formed on each end face of each piezoelectric element of the two rows of piezoelectric element rows, and the end face electrodes on the opposite end face side of each piezoelectric element row are connected to each piezoelectric element on the substrate. Each piezoelectric element row is connected to a common electrode provided between the element rows, and the end face electrodes on the end face side of each piezoelectric element row which are not opposed to each other are divided by a dividing groove formed on the substrate in a direction orthogonal to the direction in which the plurality of piezoelectric elements are arranged. Since individual electrodes are connected to individual electrodes that are divided independently for each element, an individual electrode pattern is formed in advance on the substrate, and the individual electrodes are used when the piezoelectric element plate is cut and divided into individual piezoelectric elements. The pattern can be divided into individual electrodes that connect the end face electrodes of each piezoelectric element,
Extraction of individual electrodes is simplified.

According to a second aspect of the present invention, in the inkjet head of the first aspect, a common groove deeper than the dividing groove is formed between the piezoelectric element rows in the direction in which the plurality of piezoelectric elements are arranged on the substrate. Since the common electrode is formed in the common groove, a common electrode that is not divided when divided into individual piezoelectric elements and individual electrodes can be secured, so that not only the individual electrodes are held but also the common electrode can be easily taken out.

According to a third aspect of the present invention, there is provided a method of manufacturing an ink jet head, wherein two piezoelectric element plates having an individual electrode pattern formed in advance on a substrate and end electrodes formed on both end surfaces thereof are independently provided in parallel on the substrate. And each piezoelectric element plate
Then, the two piezoelectric element plates and the individual electrode pattern on the substrate are cut at a predetermined pitch at the same time, and the two piezoelectric element plates are separated from each other. At the same time as dividing the piezoelectric element into a plurality of piezoelectric elements constituting the element array, the individual electrode pattern on the substrate is divided into individual electrodes connecting the end face electrodes for each piezoelectric element.

According to a fourth aspect of the present invention, in the method of the third aspect, the two piezoelectric element plates and the individual electrode patterns on the substrate are simultaneously cut at a predetermined pitch. ,
By joining or applying a conductive member serving as a common electrode between the two piezoelectric element rows, the common electrode can be easily secured and the common electrode can be easily taken out.

According to a fifth aspect of the present invention, there is provided a method of manufacturing an ink jet head according to the third aspect, wherein a pattern for a common electrode is formed in advance in a direction in which a plurality of piezoelectric elements are arranged on a substrate. By joining or applying a conductive member on the common electrode pattern divided by the processing, the common electrode can be easily drawn out.

According to a sixth aspect of the present invention, in the method for manufacturing an ink jet head according to the fifth aspect, a common groove having a depth which is not divided at the time of cutting the piezoelectric element plate is formed on the substrate in advance. Since the common electrode pattern is formed in the common groove, it is easier to take out the common electrode.

According to a seventh aspect of the present invention, in the method of manufacturing an ink jet head according to any one of the third to sixth aspects, each piezoelectric element plate is cut at a pitch twice as large as the nozzle pitch. The piezoelectric elements in the element row are a driving part piezoelectric element for applying a driving pulse and a fixed part piezoelectric element for fixing the liquid chamber, and the driving part piezoelectric elements can be alternately arranged, thereby achieving high integration of the head. it can.

[0025]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an external perspective view of an inkjet head showing one embodiment of the present invention, FIG. 2 is an exploded perspective view of FIG.
1 is a sectional view taken along the line AA of FIG. 1, and FIG. 4 is a sectional view taken along the line BB of FIG.

This ink jet head comprises an actuator unit 1 and a liquid chamber unit 2 joined on the actuator unit 1. The actuator unit 1 joins two rows of piezoelectric elements 4 and 4 formed by arranging a plurality of piezoelectric elements on a substrate 3 and a frame 5 surrounding the two rows of piezoelectric elements 4 and 4 with an adhesive 6. ing. The piezoelectric element array 4 includes a plurality of piezoelectric elements (hereinafter referred to as “driving section piezoelectric elements”) 7 to which a driving pulse for making ink droplets fly is provided, and driving section piezoelectric elements 7, 7. A plurality of piezoelectric elements (hereinafter, referred to as “fixed part piezoelectric elements”) 8, 8,. I have.

In the liquid chamber unit 2, a liquid chamber flow path forming member 13 made of a photosensitive resin film (dry film resist) for forming a pressurized liquid chamber flow path and the like is formed on a diaphragm 12 having a diaphragm portion 11 formed thereon. A nozzle plate 1 having a plurality of nozzles 15 formed on the liquid chamber flow path forming member 13 by bonding.
The piezoelectric element row 4 is formed by the vibrating plate 12, the liquid chamber flow path forming member 13, and the nozzle plate 16.
, And a plurality of substantially independent pressurized liquid chambers 17 each having a diaphragm portion 11 opposed to each of the driving piezoelectric elements 7, 7. 7, 7,... Are arranged. The liquid chamber unit 2 has a configuration in which the diaphragm 12 has an adhesive 18.
Thus, it is joined to the actuator unit 1 with high rigidity.

Here, the substrate 3 of the actuator unit 1 has a thickness of about 0.5 to 5 mm and is made of a material similar to a piezoelectric element, and can be cut together with the piezoelectric element by, for example, a diamond grindstone. Preferably,
In this embodiment, a ceramic substrate is used.

At both ends of the substrate 3 in a direction perpendicular to the direction in which the piezoelectric elements are arranged, the end faces of the individual piezoelectric elements 7 and 8 of the piezoelectric element rows 4 and 4 which are not opposed to each other are not opposed to each other. Each piezoelectric element 7, 8 divided by the dividing groove 21 to be connected
.. Are formed independently of each other, and each of the piezoelectric element rows 4 and 4 is separated from the corresponding one of the divided grooves 21 in a direction orthogonal to the divided grooves 21 (the direction in which the piezoelectric elements are arranged). A deep common groove 23 is formed, and a common electrode 24 is formed in the common groove 23 to connect the opposing end faces of the individual drive piezoelectric elements 7 and the fixed piezoelectric elements 8 of each of the piezoelectric element rows 4 and 4. I have. An ink supply pipe 25 is connected to an ink supply hole 3a formed at an end of the substrate 3.

Drive unit piezoelectric element 7 constituting piezoelectric element array 4
As the fixed portion piezoelectric element 8, a laminated piezoelectric element having ten or more layers is used. As shown in FIG. 3, for example, this laminated piezoelectric element has a PZT thickness of 20 to 50 μm / 1 layer.
(= Pb (Zr.Ti) O ₃ ) 26 and internal electrodes 27 made of silver / palladium (AgPd) having a thickness of several μm / 1 layer are alternately laminated. A drive voltage can be reduced by using a laminated type having a thickness of 20 to 50 μm / 1 layer, and for example, an electric field strength of 1000 V / mm of the piezoelectric element can be obtained with a pulse voltage of 20 to 50 V. The material used for the piezoelectric element is not limited to the above, and BaTiO ₃ and PbTi generally used as the piezoelectric element material are used.
A ferroelectric material such as O ₃ or (NaK) NbO ₃ can also be used.

On both end faces of the driving portion piezoelectric element 7 of each piezoelectric element row 4, end face electrodes 28 and 29 made of AgPd in which a large number of internal electrodes 27 and 27 are connected every other layer are provided. Are connected to the common electrode 24 on the substrate 3 via a conductive adhesive 31 so that each of the piezoelectric element rows 4, 4 is connected.
Of the end face electrode 2 on the end face side of each drive unit piezoelectric element 7 which does not face
Are connected to the individual electrodes 22, 2,... On the substrate 3 via a conductive adhesive 32. Each individual electrode 22, 22
.. And the common electrode 24 are connected to an FPC cable 33. When a driving voltage is applied, an electric field is generated in the laminating direction, and the driving piezoelectric element 7 is displaced in the laminating direction. The fixed-part piezoelectric element 8 is also provided with an electrode in the same manner as the driving-part piezoelectric element 7 in the manufacturing process.
Only one of them is selectively driven).

The frame 5 is made of resin, as shown in FIG.
Through holes 5a and 5b corresponding to the piezoelectric element rows 4 and 4 are formed in a plate-like member made of ceramics, metal, or the like, and the end portions correspond to the ink supply holes 3a of the substrate 3. An ink supply hole 5c is formed.

Next, as shown in FIG. 3, the diaphragm 12 of the liquid chamber unit 2 has a flat surface on the lower liquid chamber flow path forming member 13 side and a diaphragm area 12a having a different thickness on the piezoelectric element row 4 side. , A joining area 12b and a relief area 12c, and a diaphragm section 11 corresponding to the driving piezoelectric elements 7, 7,... Of the piezoelectric element row 4.

The liquid chamber flow path forming member 13 is located between the upper surface of the vibration plate 12 and the nozzle plate 16 and forms a flow path of the pressurized liquid chamber 17 and the like. It comprises a chamber flow path forming member 40 and an upper liquid chamber flow path forming member 41.

The lower liquid chamber flow path forming member 40 is
.. Made of a photosensitive resin film adhered to the upper surface, together with the upper liquid chamber flow path forming member 41, as shown in FIG. A number of inner partition walls 43 which form independent flow paths of the pressurized liquid chamber 17 and also form a fluid resistance portion 42 which also serves as an ink supply path to each pressurized liquid chamber 17; 17 and an outer peripheral partition wall 45 forming a common ink flow path 44. The inner partition 43 has two piezoelectric element rows 4 and 4.
Two rows are formed corresponding to the rows being formed, and the common ink flow path 44 is provided between the rows. The upper liquid chamber flow path forming member 41 has substantially the same configuration as the lower liquid chamber flow path forming member 40, but the fluid resistance portion 42 of the lower liquid chamber flow path forming member 40.
The difference is that there is no part corresponding to.

The nozzle plate 16 is provided with a number of nozzles 15 which are fine holes for ejecting ink droplets.
The nozzle 15 is provided at a position corresponding to the vicinity of the center of the pressurized liquid chamber 17. The nozzle plate 16 is formed of Si, a metal material, or the like.

In this ink-jet head, the driving piezoelectric elements 7, 7,... Of the piezoelectric element rows 4, 4 are arranged in a staggered manner, that is, orthogonal to the nozzle arrangement direction (the direction in which the piezoelectric elements are arranged). When viewed in the direction, the driving part piezoelectric element 7 of one piezoelectric element row 4 and the fixed part piezoelectric element 8 of the other piezoelectric element row 4 are in the same row, and the fixed part piezoelectric element 8 of one piezoelectric element row 4 is The driving units of the piezoelectric element row 4 are used so that the piezoelectric elements 7 are arranged in the same row. Accordingly, the diaphragm units 11, 11,..., The pressurized liquid chambers 17, 17,. The nozzle pitch is highly integrated.

Next, the manufacturing process of the ink jet head will be described. This ink jet head is manufactured by separately assembling the actuator unit 1 and the liquid chamber unit 2 in advance, and then bonding and bonding the units 1 and 2 to each other. By adopting such a manufacturing process,
A non-defective product of the two units 1 and 2 can be selected and assembled, thereby improving the yield, and also having an actuator unit 1 in which dust is likely to be generated in the processing and assembling process, and a liquid chamber unit 2 in which dust should be completely prevented from adhering. Can be assembled in separate steps, so that the quality itself of the completed inkjet head is improved. Hereinafter, a specific description will be given.

First, the steps of processing and assembling the actuator unit 1 are as follows. That is, as shown in FIG. 5, ink supply holes 3a are formed in the substrate 3 in advance, and two piezoelectric element plates 65, 65 described later are formed.
Between the joining positions along the common groove 2 along the direction in which the piezoelectric elements are arranged.
Form 3 The common groove 23 is provided in the piezoelectric element plate 6.
5 is formed deeper than the dividing groove 21 which is a cutting groove at the time of cutting. The individual electrodes 22 are provided on both sides of the substrate 3.
Are formed, and a common electrode pattern 62 is formed in the common groove 23 and along the vicinity thereof. The individual electrode pattern 61 and the common electrode pattern 62 are formed by depositing a conductive material, for example, Ni.Au.

As shown in FIGS. 6 and 7, two laminated piezoelectric elements having end electrodes 63 and 64 for forming the end electrodes 28 and 29 on both end surfaces were formed in a plate shape. The piezoelectric element plates 65, 65 are arranged in parallel at predetermined intervals on the substrate 3 using a positioning jig , and one end face of each of the piezoelectric element plates 65, 65 is provided.
The electrodes 64, 64 are bonded together in a state where they face each other. Thereafter, the end face electrodes 63, 63 on the non-opposite sides of the two piezoelectric element plates 65, 65 are electrically connected to the individual electrode patterns 61, 61 on the substrate 3 by a conductive member 66 such as a conductive adhesive. While connecting, two piezoelectric element plates 65,
65 opposed end surface electrodes 64, 64 are electrically connected to the common electrode pattern 62 on the substrate 3 by a conductive member 67 such as a conductive adhesive.

Next, as shown in FIGS. 8 and 9, the two piezoelectric element plates 65, 65 are attached to the end face electrodes 63, 6 by a dicer or the like on which a diamond grindstone is set.
The individual piezoelectric elements 6 which are cut at a predetermined pitch in a direction orthogonal to
8 and 68. At the same time, the end face electrodes 63 and 64 are divided for each piezoelectric element 68, 68.
8, 29.

At this time, the individual piezoelectric elements 68, 68,.
The upper individual electrode patterns 61, 61
8,68 ... is divided independently for each, individual electrodes 22 and 22
... is formed. The individual electrodes 22, 22,... Remain connected to the end surface electrodes 28, 28,.

On the other hand, the common electrode pattern 62 on the substrate 3
Are partially divided for each of the piezoelectric elements 68, 68..., But since the divided grooves 21 do not reach the common groove 23 of the substrate 3, the common electrode pattern 62 is
.. Remain connected to all the end face electrodes on the opposite end face side of the row of piezoelectric elements 68. Therefore, by using the electrode pattern 62 as the common electrode 24, it is possible to easily secure the common electrode 24 connected to the opposed end electrodes 29 of the two rows of piezoelectric elements 68.

As described above, here, the individual electrode patterns 61 are formed in advance on the substrate, and the common grooves 23 having a depth which is not divided at the time of cutting are formed between the respective piezoelectric element plates to be joined. A common electrode pattern 62 is formed in the common groove 23, and two piezoelectric element plates 65, 65 each having end face electrodes 63, 64 formed on both ends thereof on the substrate 3, are independently arranged in parallel with each piezoelectric element. plate
After bonding in a state where one end surface electrode 64 of 65, 65 is opposed to each other , these two piezoelectric element plates 65, 65 and the individual electrode patterns 61, 61 on the substrate 3 are simultaneously cut at a predetermined pitch. , Two piezoelectric element plates 6
At the same time, the individual electrode patterns 61 on the substrate 3 are divided into independent individual electrodes 22 for each piezoelectric element 68, Moreover, the common electrode pattern 62 is not divided.

In this way, it is particularly easy to take out the electrodes from each piezoelectric element 68 (driving unit piezoelectric element 7), which is a laminated piezoelectric element, and furthermore, the opposite end face electrodes of two rows of piezoelectric elements. Connecting to the common electrode makes it easy to take out the individual electrodes for connection to the drive circuit.In addition, by providing a common electrode pattern that is not divided by the cutting process, before applying a fine mechanical cutting process A common electrode can be secured, and individual piezoelectric elements formed by mechanical cutting are not destroyed or damaged in a later step, thereby simplifying the step and further improving the yield. Further, the number of cutting steps is reduced as compared with a method in which one piezoelectric element plate is used to divide the piezoelectric element plate into two, and each row of the piezoelectric element plates is further divided into individual piezoelectric elements.

Here, the cutting pitch of the piezoelectric element plate 65 will be described. In this ink jet head, as shown in FIGS.
The width (the width in the column direction) of the piezoelectric element 8 and the fixed portion is formed to have the same width L, and the pitch Pa
Are formed so as to be twice the pitch Pn of the nozzles 15 to form the piezoelectric elements 68.

.. Can be arranged in a zigzag pattern, so that the pitch of the nozzles 15 can be reduced, and High integration can be easily realized.

In this manner, the frame 5 is bonded and bonded to the substrate 3 on which the processing of the piezoelectric element has been completed, and the FPC cable 33 is bonded to the individual electrodes 22 and 22 and the common electrode 24 of the substrate 3 by heat and pressure. Thus, the actuator unit 1 is completed. The FPC cable 33 is connected to the piezoelectric elements 68, 68.
.. Have a pattern that can selectively drive the piezoelectric element 68 to be the driving piezoelectric element 7, and the joints thereof are plated in advance with solder.

On the other hand, the processing and assembling process of the liquid chamber unit 2 will be described. The photosensitive resin for forming the lower liquid chamber flow path forming member 40 on the flat surface of the diaphragm 12 has a thickness of 20 mm. A dry film resist having a thickness of about 50 μm is laminated by heat and pressure, and is exposed to ultraviolet light using a mask corresponding to a flow path pattern to cure the exposed portion. Then, using a solvent capable of removing the unexposed portion, the unexposed portion is removed and developed to form a liquid chamber pattern of the lower liquid chamber flow path forming member 40 as shown in FIG. After that, the main curing is performed again by ultraviolet exposure and heat.

A dry film resist having a thickness of about 40 to 100 μm, which is a photosensitive resin for forming the upper liquid chamber flow path forming member 41, is also laminated on the nozzle plate 16 by heat and pressure. Exposure to UV using a mask according to the, the exposed part is cured,
The unexposed portion is developed to form a liquid chamber pattern of the upper liquid chamber flow path forming member 41 (there is no fluid resistance portion 42 as described above).
Is formed, washed with water, dried and then hardened again by UV exposure and heat

Then, the corresponding surfaces of the lower liquid chamber flow path forming member 40 and the upper liquid chamber flow path forming member 41 made of the dry film resist formed on the vibration plate 12 and the nozzle plate 16 are joined. I do. This joining is performed using a positioning jig, and pressure and heating at a higher temperature than in the main curing are performed.

Next, the actuator unit 1 and the liquid chamber unit 2 completed as described above are assembled. That is, first, the piezoelectric element 6 of the actuator unit 1
8, 68... And the surface of the frame 5 are coated with an adhesive 18 such as an epoxy adhesive using a screen printing machine, and the actuator unit 1 is fixed to a positioning jig which can be aligned. The two units 1 and 2 are joined together with the plate 12 side (joining surface) facing downward. In this case, the epoxy adhesive is left to react and cure under a pressurized state of several kg / cm ^{2. As} the adhesive, an acrylic two-pack non-mixing type or a cyanoacrylate type is used. May be instantaneously joined. Finally, the ink supply pipe 25 is inserted into the ink supply hole 3a of the substrate 3, and an adhesive is applied and cured to fix it.

Next, the operation of the ink jet head constructed as described above will be described. A driving pulse of 20 to 50 V is selectively applied to the driving piezoelectric elements 7, 7... Of the piezoelectric element rows 4, 4 according to the recording signal. When the voltage is applied, the driving piezoelectric element 7 to which the pulse voltage is applied is displaced, and the corresponding diaphragm 11 of the diaphragm 12 is moved to the nozzle 1.
The ink is deformed in five directions, and the ink in the pressurized liquid chamber 17 is pressurized by a change in the volume (volume) of the pressurized liquid chamber 17, and the ink is ejected as droplets from the nozzles 15 of the nozzle plate 16 to perform recording. be able to.

Then, the ink pressure in the pressurized liquid chamber 17 decreases as the ink droplets are ejected, and a slight negative pressure is generated in the pressurized liquid chamber 17 due to the inertia of the ink flow at this time. In this state, by turning off the application of the voltage to the drive unit piezoelectric element 7, the diaphragm portion 11 of the diaphragm 12 returns to the original position, and the pressurized liquid chamber 17 becomes the original shape. , Further negative pressure is generated.

At this time, the ink that has entered from the ink supply pipe 19 that leads to the ink tank (not shown) passes through the common ink flow path 44 and fills the pressurized liquid chamber 17 from the fluid resistance part 42. Then, after the vibration of the ink meniscus surface of the nozzle 15 is attenuated and stabilized, a pulse voltage is applied to the driving unit piezoelectric element 7 for discharging the next ink droplet.

In this case, by forming the deformed portion of the diaphragm 12 as the diaphragm portion 11, the displacement generated by the piezoelectric element 7 in the driving portion can be efficiently transmitted to the pressurized liquid chamber 17, and the displacement can be increased. Vibration propagation to portions other than the pressurized liquid chamber 17 is reduced. Further, at the time of ink ejection, an ink flow is generated in a flow direction from the pressurized liquid chamber 17 to the common ink flow path 44, and this flow path is formed as a fluid resistance portion 42 having a smaller cross-sectional area than the other. Therefore, the backflow from the pressurized liquid chamber 17 to the common ink flow path 44 is extremely reduced, and the drop in the ink droplet ejection efficiency is prevented.

Next, an example of another processing and assembling process of the actuator unit 1 will be described with reference to FIGS. Here, as shown in FIG. 11, a flat substrate on which the common groove 23 of the above embodiment is not formed is used as the substrate 3, and individual electrode patterns 61 for forming the individual electrodes 22 on both sides thereof are used. 61, and a common electrode pattern 62 is formed at the center.

Then, as shown in FIGS. 12 and 13,
The piezoelectric element plates 65, 65 in which two laminated piezoelectric elements formed with the end surface electrodes 63, 64 are formed in a plate shape in the same manner as in the above-described embodiment, are placed at predetermined intervals on the substrate 3 using a positioning jig. Independent and in parallel with the piezoelectric element
After bonding with one end surface electrode 64 of the rate 65 facing the other, the end surface electrodes 63, 63 on the non-opposite side of the two plate-shaped piezoelectric elements 65, 65 are connected to the individual electrode patterns 61, 63 on the substrate 3. 61, and electrically connected to a conductive member 66 by a conductive member 66.
Are electrically connected to the common electrode pattern 62 on the substrate 3 by a conductive member 67.

Next, as shown in FIG. 14, similarly to the above embodiment, the two piezoelectric element plates 65, 65 are fixed in a direction orthogonal to the end face electrodes 63, 64 by a dicer or the like in which a diamond grindstone is set. , Which are to be the driving part piezoelectric element 7 or the fixed part piezoelectric element 8, are formed at the same time, and the end face electrodes 63, 64 are simultaneously separated from the individual piezoelectric elements 68, 68. Divide each time.

At this time, the common electrode pattern 62 on the substrate 3 is still connected to the opposite end electrodes 64, 64... (To be the end electrodes 29) of the individual piezoelectric elements 68, 68. Since each of the piezoelectric elements 68 is divided into two rows, as shown in FIG.
Of the conductive member 71 in parallel with the end face electrodes 64, 64 between the end face electrodes 64, 64 facing each other (to be end face electrodes 29, 29).
Is applied to electrically connect the divided common electrode patterns 62. Thus, the common electrode 24 can be easily obtained.

In this case, as shown in FIGS. 16 and 17, two rows of piezoelectric elements 68, 68,.
64 (become end electrodes 29, 29) between the end surface electrodes 64,
Even if the common electrode pattern 62 divided by joining the conductive members 72 in parallel with the 64 is electrically connected,
The common electrode 24 can be easily obtained.

Next, another example of the cutting pitch of the piezoelectric element plate 65 will be described with reference to FIGS. Here, the width L1 of the driving unit piezoelectric element 7 and the width L2 of the fixed unit piezoelectric element 8 are made different from each other to
Is cut so that the pitch Pa is the same as the pitch Pn of the nozzle 15.

As described above, by making the width L1 of the driving unit piezoelectric element 7 different from the width L2 of the fixed unit piezoelectric element 8, the pressurized liquid chambers 17, 17,. .. Can be arranged in the same row, and higher integration can be achieved.

Next, another ink jet head will be described with reference to FIG. 20. Here, two rows of pressurized liquid chambers 1 are arranged on the diaphragm 12 between two rows of piezoelectric elements 4 and 4.
A central partition wall 73 is formed between 7, 17,..., And the common ink flow path 44 is connected to the common ink flow path 44a and the common ink flow path 44.
b, and the ink supply holes 12d, 12e, 5c, 5d and 3 for supplying ink to the common ink flow paths 44a and 44b also in the diaphragm 12, the frame 5 and the substrate 3.
a, 3b to form two ink supply pipes 25a, 2b.
5b is connected.

By doing so, the color of the ink supplied to each of the common ink flow paths 44a and 44b can be made different, and a compact color ink jet head can be obtained.

The present invention is not limited to the ink jet head using displacement of the piezoelectric element in the direction perpendicular to the direction of the electric field (displacement in the direction d33).
Directional displacement). Further, in the above-described embodiment, an example in which the opening direction of the nozzle is applied to a side shooter type ink jet head coaxial with the displacement direction of the piezoelectric element has been described, but the opening direction of the nozzle is orthogonal to the displacement direction of the piezoelectric element. The invention can also be applied to an ink jet head of an edge shooter type which is oriented.

[0067]

As described above, according to the ink jet head of the first aspect, the end face electrodes are formed on both end faces of each of the piezoelectric elements of the two rows of the piezoelectric elements, and the end face sides of each of the piezoelectric element rows are opposed to each other. Are connected to a common electrode provided between the piezoelectric element rows on the substrate, and the end face electrodes on the end faces of the piezoelectric element rows that are not opposed to each other are arranged in a direction orthogonal to the row direction of the plurality of piezoelectric elements on the substrate. German each piezoelectric element at the formed dividing grooves
Having connected to the individual electrodes divided by standing, extraction of the individual electrodes and the common electrode connected to the driving circuit is simplified,
The number of assembling steps can be reduced, and the production efficiency and yield can be improved.

According to the second aspect of the present invention, a common groove deeper than the dividing groove is formed between the piezoelectric element rows on the substrate in the direction in which the plurality of piezoelectric elements are arranged, and the common electrode is formed in the common groove. Since it is formed, it is possible to secure a common electrode that is not divided when dividing into individual piezoelectric elements and individual electrodes, it is easier to take out the electrodes, and the divided piezoelectric elements are damaged or broken in a later process Therefore, it is possible to further simplify the process and improve the yield.

According to the method of manufacturing an ink jet head according to the third aspect, two piezoelectric element plates in which individual electrode patterns are formed in advance on the substrate and end electrodes are formed on both end surfaces thereof are independently provided in parallel on the substrate. And each piezoelectric element
After bonding with the one end face electrodes of the plates facing each other, the two piezoelectric element plates and the individual electrode patterns on the substrate are simultaneously cut at a predetermined pitch to form two electrodes.
At the same time, each piezoelectric element plate is divided into a plurality of piezoelectric elements constituting each piezoelectric element row, and at the same time, the pattern for individual electrodes on the substrate is divided into individual electrodes connecting end face electrodes of each piezoelectric element. Extraction is simplified, the number of assembly steps can be reduced, and production efficiency and yield can be improved.

According to the method for manufacturing an ink jet head of the fourth aspect, the two piezoelectric element plates and the individual electrode patterns on the substrate are simultaneously cut at a predetermined pitch and then opposed to each other between the two piezoelectric element rows. By joining or applying a conductive member serving as a common electrode connected to the end face electrode,
The common electrode can be easily secured, the common electrode can be easily taken out, and the production efficiency and the yield can be improved.

According to the method of manufacturing an ink jet head according to the fifth aspect, the common electrode pattern is formed on the substrate in the direction in which a plurality of piezoelectric elements are arranged in advance between the piezoelectric element plates to be joined in advance. By joining or applying a conductive member on the common electrode pattern divided by the above, the common electrode can be easily pulled out to the outside, and the production efficiency and the yield can be further improved.

According to the method of manufacturing an ink jet head according to the sixth aspect, a common groove is formed on the substrate between the piezoelectric element plates to be joined in advance at a depth that is not divided at the time of cutting, and the common groove is formed in the common groove. Since the electrode pattern is formed, it is possible to secure a common electrode that is not divided when dividing into individual piezoelectric elements and individual electrodes, and it is easier to take out the electrodes further, and the divided piezoelectric elements are not damaged in a later process. It is possible to further simplify the process and improve the yield without causing breakage.

According to the method of manufacturing an ink jet head according to the seventh aspect, since each piezoelectric element plate is cut at a pitch twice as large as the nozzle pitch, a driving unit piezoelectric element for applying a driving pulse to the piezoelectric elements in each piezoelectric element row. The piezoelectric elements in the fixed part for fixing the liquid chamber and the liquid chamber can be arranged alternately with the piezoelectric elements in the driving part, so that high integration can be achieved.

[Brief description of the drawings]

FIG. 1 is an external perspective view of an inkjet head showing one embodiment of the present invention.

FIG. 2 is an exploded perspective view of FIG. 1;

FIG. 3 is a sectional view taken along the line AA in FIG. 1;

FIG. 4 is a sectional view taken along the line BB of FIG. 1;

FIG. 5 is a perspective view of a substrate for explaining a process of assembling and assembling the actuator unit.

FIG. 6 is a perspective view showing a state in which a piezoelectric element plate is joined to a substrate used for explaining the same process.

FIG. 7 is a sectional view taken along the line CC of FIG. 6;

FIG. 8 is a perspective view showing a state after a piezoelectric element plate cutting process for explaining the same process.

FIG. 9 is a sectional view taken along line DD in FIG. 8;

FIG. 10 is an explanatory diagram for explaining a pitch of a piezoelectric element row and a nozzle;

FIG. 11 is a perspective view of a substrate for explaining another processing and assembling process of the actuator unit.

FIG. 12 is a perspective view showing a state in which a piezoelectric element plate is joined to a substrate used for explaining the same process.

FIG. 13 is a sectional view similar to FIG. 7 of FIG. 12;

FIG. 14 is a perspective view showing a state after a piezoelectric element plate cutting process for explaining the same step;

FIG. 15 is a perspective view showing a state where a common electrode conductive member is provided for explaining the same step.

FIG. 16 is a perspective view showing a state in which another common electrode conductive member is provided for explaining the same step.

FIG. 17 is a sectional view taken along the line EE in FIG. 16;

FIG. 18 is an exploded perspective view of a main part for explaining another example of the pitch of the piezoelectric element row and the nozzle.

FIG. 19 is a sectional view similar to FIG. 4 used for the same description.

FIG. 20 is an exploded perspective view of a main part used for describing another ink jet head.

[Explanation of symbols]

1. Actuator unit, 2. Liquid chamber unit, 3.
Substrate, 4 ... piezoelectric element row, 5 ... frame, 6 ... adhesive, 7
... Drive piezoelectric element, 8 fixed part piezoelectric element, 11 diaphragm part, 12 diaphragm, 13 liquid chamber channel forming member, 1
5 nozzle, 16 nozzle plate, 17 pressurized liquid chamber,
Reference numeral 21: dividing groove, 22: individual electrode, 23: common groove, 24:
Common electrode, 27 ... internal electrode, 28, 29 ... end face electrode, 6
1 ... pattern for individual electrode, 62 ... pattern for common electrode,
63, 64: End face electrode, 65: Piezoelectric element plate, 6
6, 67: conductive member; 68: piezoelectric element.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tetsuro Hirota 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Osamu Naruse 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Hideyuki Makita 1-3-6 Nakamagome, Ota-ku, Tokyo Co., Ltd. Inside Ricoh Company (72) Yoshihisa Ota 1-3-6 Nakamagome, Ota-ku, Tokyo Co., Ltd. Ricoh Co., Ltd. (72) Inventor Tsutomu Sasaki 1-3-6 Nakamagome, Ota-ku, Tokyo Co., Ltd. Ricoh Co., Ltd. (56) References JP-A-4-125158 (JP, A) International Publication 95/10416 (WO , A1) (58) Field surveyed (Int. Cl. ⁷ , DB name) B41J 2/045 B41J 2/055 B41J 2/16

Claims (7)

(57) [Claims] 1. An ink jet head in which at least two piezoelectric element rows each consisting of a plurality of piezoelectric elements arranged at a predetermined pitch on a substrate are arranged, both end faces of each piezoelectric element of the two rows of piezoelectric elements are provided. Are respectively formed with end face electrodes, the end face electrodes on the opposite end faces of the respective piezoelectric element rows are connected to a common electrode provided between the respective piezoelectric element rows on the substrate, and the non-opposing end face sides of the respective piezoelectric element rows are provided. An end face electrode is connected to an individual electrode provided on the substrate, and the individual electrode on the substrate is independent for each piezoelectric element by a division groove formed in a direction orthogonal to a direction in which the plurality of piezoelectric elements are arranged. ink jet head is characterized in that it is divided by. 2. The ink jet head according to claim 1, wherein a common groove deeper than the dividing groove is formed between the piezoelectric element rows in the direction in which the plurality of piezoelectric elements are arranged on the substrate. An ink jet head, wherein the common electrode is formed therein. 3. A method for manufacturing an ink jet head in which at least two rows of piezoelectric elements formed of a plurality of piezoelectric elements arranged on a substrate are arranged, an individual electrode pattern is formed on the substrate in advance, and both end faces are formed. The two piezoelectric element plates having end electrodes formed on the substrate are independently arranged in parallel on the substrate , and one end electrode of each piezoelectric element plate is paired.
Then , the two piezoelectric element plates and the individual electrode patterns on the substrate are simultaneously cut at a predetermined pitch to form the respective piezoelectric element rows. A method for manufacturing an ink-jet, comprising: dividing an individual electrode pattern on the substrate into individual electrodes for each piezoelectric element at the same time as dividing the plurality of piezoelectric elements. 4. The method for manufacturing an ink jet head according to claim 3, wherein the two piezoelectric element plates and the individual electrode patterns on the substrate are cut at the same time at a predetermined pitch. And a conductive member serving as a common electrode connected to the opposite end face electrodes of the piezoelectric elements. 5. The inkjet head manufacturing method according to claim 3, wherein a pattern for a common electrode is previously formed on the substrate in a direction in which the plurality of piezoelectric elements are arranged. Manufacturing method. 6. The method for manufacturing an ink jet head according to claim 5, wherein a common groove having a depth that is not divided at the time of cutting the piezoelectric element plate is formed on the substrate, and the common groove is formed in the common groove. A method for manufacturing an ink-jet head, wherein an electrode pattern is formed. 7. The method for manufacturing an ink jet head according to claim 3, wherein each piezoelectric element plate is cut at a pitch twice as large as a nozzle pitch.