JPH10250073A - Ink jet head, electric conducting part and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drive respective piezoelectric members uniformly by employing a photosensitive conductor at least partially in an electric connection path for applying an electric signal to an energy generating body, thereby relieving the work for precisely forming a fine pattern by photography method while preventing conduction between wirings. SOLUTION: An individual electrode 60 and a common electrode 62 extending alternately between thin piezoelectric layers from external electrodes 56, 58 are provided in a multilayer piezoelectric member 42 and individual and common wirings 70, 72 corresponding to respective piezoelectric members 42 are patterned on a substrate 22 by screen printing, for example. The external electrode 56 conducting to each individual electrode 60 is connected electrically through a micromachinable photosensitive conductor 74 with the individual wiring 70 being connected with a driver circuit through a flexible wiring 78. The external electrode 58 conducting to the common electrode 62 is connected electrically through a photosensitive conductor 76 with the common wiring 72. An electric signal corresponding to the image signal is applied from the driver circuit to the active part 42a, 42b of each piezoelectric member 42 through the wiring 78, 70, the conductor 74 and the electrode 56, 60.

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 an image by driving an energy generator based on an electric signal to cause ink droplets to fly from nozzles and attaching the ink droplets to a recording medium such as recording paper. The present invention relates to an electrical conduction section formed by electrically connecting two conductive sections by a connection section.

[0002]

2. Description of the Related Art Conventionally, in an ink jet head,
2. Description of the Related Art There is known an energy generator using a piezoelectric member as an energy generator for causing ink in an ink chamber to fly from a nozzle in the form of droplets. This type of head usually includes a plurality of ink chambers arranged at a fine pitch, and a plurality of piezoelectric members are arranged on the substrate corresponding to the respective ink chambers. Each of the piezoelectric members is generally formed by fixing a flat plate-shaped piezoelectric plate to a substrate and then performing mechanical processing with a dicing saw or the like to cut the piezoelectric members.

In order to apply an electric signal to each of the thus formed piezoelectric members so that they can be driven independently of each other, it is necessary to electrically connect the electrodes of each of the piezoelectric members to a driver circuit individually. One of the methods is a method in which conductive paste is applied between the electrodes of each piezoelectric member and the lead-out lines formed on the substrate corresponding to each piezoelectric member and individually connected to a driver circuit by applying a conductive paste. There is.

[0004]

However, since the piezoelectric members are arranged at a very small pitch corresponding to the ink chambers, the interval between the adjacent piezoelectric members and the lead-out wiring becomes extremely small, for example, several tens of μm. I have. Therefore, the operation of applying the conductive paste without protruding so as not to conduct between adjacent wirings is a difficult operation requiring high precision. In addition, the application state of the conductive paste tends to vary, and the problem that the piezoelectric members cannot be driven uniformly tends to occur.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a first aspect of the present invention provides an ink jet head that drives an energy generator by an electric signal to fly an ink droplet. At least a part of the electrical connection path for applying the voltage is made of a photosensitive conductor.

In this ink jet head, the energy generator may be a piezoelectric member.

The ink jet head according to the first aspect of the present invention comprises:
A photosensitive conductive paste is applied to the electrode of the energy generator and the vicinity thereof, and after pattern exposure is performed on a portion corresponding to the electrode, the photosensitive conductive paste in an unexposed portion is removed by development, and the remaining photosensitive conductor is removed. It is manufactured by a method that is part of an electrical connection path for applying an electrical signal to the energy generator.

[0008] In a second aspect of the present invention, the first conductive portion and the second conductive portion are provided.
And a connection portion for electrically connecting both of the conductive portions, wherein the connection portion is made of a photosensitive conductor.

The electrically conductive portion is formed by applying a photosensitive conductive paste to the first and second conductive portions and the vicinity thereof, and to a photosensitive conductor in a region connecting the first and second conductive portions. After the pattern exposure, the unexposed photosensitive conductive paste is removed by development, and the remaining photosensitive conductor is used as a connecting portion for electrically connecting the first and second conductive portions.

[0010]

According to the ink jet head of the first invention,
At least a part of an electric connection path for applying an electric signal to the energy generator is formed of a photosensitive conductor. Since the photosensitive conductor can precisely form a fine pattern by a well-known photolithography method, an electric connection path that does not conduct to each of the energy generators such as piezoelectric members arranged at a fine pitch can be accurately formed.
And it can be formed uniformly.

In the second aspect of the present invention, since the connecting portion between the first and second conductive portions is formed of a photosensitive conductive material, not only the ink jet head, each conductive portion is very Even when a plurality of connection portions are formed at narrow intervals, the connection portions can be formed accurately, uniformly, and easily so that adjacent connection portions do not conduct with each other.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 3 show an inkjet head 10 according to the first invention. The head 10 has a large-diameter ink droplet ejection head portion (hereinafter, referred to as a “large-diameter head portion”) 12 opposed to the center line 34 therebetween.
And a small-diameter ink droplet ejection head unit (hereinafter, referred to as a “small-diameter head unit”) 14. The top plate 16, the partition wall 18, the vibration plate 20, and the substrate are integrally stacked on each other in this order. In the present embodiment described below, the nozzle diameter of the large-diameter head portion and the nozzle diameter of the small-diameter head portion are different. However, the present invention is not limited to this. The invention is applicable.

The top plate 16 is made of ceramics, synthetic resin, metal, or the like. The surface facing the partition 18 is formed at the same time as the formation of the top plate 16 by electroforming or photolithography.
Alternatively, a plurality of groove-shaped concave portions are formed by fine processing after forming the top plate. By covering these recesses with the partition walls 18, the large-diameter head section 12 and the small-diameter head section 14 have ink chambers 26 and 27 for storing ink, an ink supply chamber 30 for storing replenishment ink, and each of the ink chambers. 2
An ink inlet 32 is formed to connect the ink supply chambers 30, 27 with the ink supply chamber 30, respectively. Ink chamber 26, 2
Numeral 7 is formed in a long groove shape extending parallel to the direction in which the head portions 12 and 14 face each other and in parallel. The ink supply chamber 30 is formed on the opposite side of the center line 34 across the ink chambers 26 and 27, and is connected to an ink tank (not shown).

The length of the ink chamber 26 of the large-diameter head section 12 in the direction orthogonal to the center line 34 is longer than that of the ink chamber 27 of the small-diameter head section 14, so that the volume of ink accommodated therein is reduced. Is getting bigger. The top plate 16 has an ink chamber 2 on the side opposite to the ink inlet 32.
Nozzles 28, 29 communicating with 6, 27 are formed by a method such as excimer laser processing. Each of the nozzles 28 and 29 is formed in a tapered shape whose opening cross section gradually decreases from the ink chambers 26 and 27 toward the ink ejection side. As shown in FIGS. 1 and 2, the nozzles 28 and 29 may be formed with a larger diameter head portion 12 than the smaller diameter head portion 14 as shown in FIGS. .

As shown in FIGS. 2 and 3, the partition 18 is made of metal,
It is made of a thin film of a synthetic resin or the like, and is fixed between the top plate 16 and the diaphragm 20.

The vibration plate 20 is made of a known piezoelectric material such as PZT, and is fixed between the partition wall 18 and a substrate 22 made of a flat plate made of ceramics, metal, synthetic resin or the like. The diaphragm 20 is formed with a vertical groove 50 by dicing.
And the piezoelectric members (energy generators) 42 and 43 which are separated by forming the lateral grooves 52 and face the ink chambers 26 and 27 and the ink supply chamber 30 via the partition 18.
And a partition wall 4 located between the adjacent piezoelectric members 42 and 43.
4 and a peripheral wall 46 located on both sides of the head. Further, as shown in FIG. 2, the piezoelectric member 42, the piezoelectric member 42,
A spacer member 48 having the same thickness as 43 and extending between the head portions 12 and 14 is provided.

FIG. 4 is an enlarged side view of the piezoelectric member 42.
The piezoelectric member 42 is, for example, a laminated piezoelectric member formed by laminating 20 piezoelectric thin layers. Inside the piezoelectric member 42, individual electrodes 60 extending alternately between the piezoelectric thin layers from the external electrodes 56 and 58 on both end surfaces are provided. It has a common electrode 62. The individual electrode 60 and the common electrode 62 overlap each other in a region corresponding to the ink chamber 26.
By applying a high voltage between 0 and 62, a polarized active portion 42a and an unpolarized non-active portion 42b are formed. In addition, the ink chambers 2 of the heads 12 and 14
The active portion 42a of the piezoelectric member 42 is formed to be longer than the active portion 43a of the piezoelectric member 43 corresponding to the difference in the length of the piezoelectric members 6 and 27 (see FIGS. 1 and 2).

On the substrate 22, a plurality of individual wirings 70 and common wirings 72 are formed in a pattern corresponding to each piezoelectric member 42 by a method such as plating or screen printing.
Then, the external electrodes 56 electrically connected to the individual electrodes 60 and the individual wires 70 are electrically connected by the photosensitive conductor 74. Each individual wiring 70 is individually connected to a driver circuit (not shown) by a flexible wiring 78. On the other hand, the external electrodes 58 electrically connected to the common electrodes 62 and the common wiring 72 are electrically connected by the photosensitive conductor 76. Each common wiring 72 is collectively connected to the ground. As a result, an electric signal is supplied to the active portion 42 of each piezoelectric member 42 from the driver circuit to the individual electrode 60 via the flexible wiring 78, the individual wiring 70, the photosensitive conductor 74, and the external electrode 56 in accordance with image information. Is applied. Therefore, the photosensitive conductor 74
Constitutes a part of an electric connection path for applying an electric signal to the piezoelectric member 42. In addition, an electric signal is applied to each piezoelectric member 43 of the small-diameter head unit 14 through a similar connection path.

The photosensitive conductors 74 and 76 are formed as follows. As shown in FIG. 5, the piezoelectric member 42, the partition wall 44, and the peripheral wall 46 which are separately formed, and the substrate 2
2 and the photosensitive conductive paste 80 along the corner formed by
Is applied to the external electrode 56, the individual wiring 70 and the vicinity thereof. The photosensitive conductive paste is similarly applied to the external electrode 58 and the common wiring 72 at the opposite end of the piezoelectric member 42. Note that, as the photosensitive conductive paste, a conventionally known photosensitive conductive paste obtained by mixing a photosensitive resin, a metal powder such as silver-palladium powder, and a plasticizer into a predetermined composition and kneading the mixture is used. Can be. Then, a quartz glass plate 86 masked with a Cr layer 84 so as to leave a rectangular hole 82 in a portion corresponding to the piezoelectric member 42 is prepared, and as shown in FIG. Is positioned and leaned on the end on the side of the external electrode 56 such that the hole 82 faces the external electrode 56. In this state, the quartz glass plate 86 is irradiated with ultraviolet rays from obliquely above, and pattern exposure is performed only on the portions of the photosensitive conductive paste 80 corresponding to the external electrodes 80 and the individual wirings 70 through the openings 82 of the mask. On the other hand, the photosensitive conductive paste 80 on the external electrode 58 side of the piezoelectric member 42 may serve as a common connection portion on the ground side and conduct between adjacent piezoelectric members 42. I do. Thereafter, the unexposed portions of the photoconductor conductive paste are removed by development. Thereby, the photosensitive conductor 7 electrically connecting the external electrode 56 and the individual 70 individually to each other.
4 and the photosensitive conductor 7 in a state where the piezoelectric members 42 electrically connecting the external electrodes 58 and the common wiring 72 are connected.
6 remains. Then, the photosensitive conductors 74 and 76 are baked and hardened.

The photosensitive conductors 74 and 76 are similarly formed for the piezoelectric member 43 of the small diameter head section 14 (see FIG. 2).

As described above, since the photosensitive conductor 74 is formed by a known photolithography method, a fine pattern can be precisely formed. Therefore, the piezoelectric members 42 and 43 arranged at a fine pitch can be formed accurately and uniformly so that the electrical connection paths for the individual electrodes 60 are not electrically connected to each other.
2, 43 can be driven stably without variation.

In the ink jet head 10, the ink supplied from the ink tank to the ink supply chamber 39 is stored in the ink chambers 26 and 27 via the ink inlet 32. In this state, when an electric signal is applied from the driver circuit, the active portions 42a, 42a of the piezoelectric members 42, 43
43a is instantaneously deformed to partition the partition wall 18 into the ink chambers 26 and 27.
Push into the side. Thereby, the pressurized ink chamber 26,
The ink in 27 flies from the nozzles 28 and 29 as ink droplets. At this time, due to the difference in length between the ink chambers 26 and 27 and the active portions 42a and 43a, the ink pressure is different between the ink chambers 26 and 27 even if an electric signal of the same voltage value is applied. An ink droplet relatively larger than 29 flies. For this reason, when these ink droplets adhere to the recording medium, large and small dots are formed, and a group of these dots records a gradation image. When the application of the electric signal is released, the active portions 4 of the piezoelectric members 42 and 43 are activated.
2a and 43a return to the original state, ink is supplied from the ink supply chamber 30 to the ink chambers 26 and 27 via the ink inlet 32 by capillary action, and is ready for the next ink droplet flight. In the present embodiment, gradation printing is performed by changing the diameter of the ink droplet by changing the diameter of the nozzle between the large diameter head portion and the small diameter head portion and the size of the active portion of the piezoelectric member. Alternatively, instead of or in addition to these, the diameter of the ink droplet may be changed by changing the magnitude of the voltage applied to the piezoelectric body as the ink pressurizing means.

In the ink jet head 10, the photosensitive electrodes 74 and 76 connect the external electrodes 56 and 58 of the piezoelectric members 42 and 43 to the individual and common wirings 70 and 72, respectively. As shown in (a) and (b), the photosensitive conductors 74 and 76 are connected to the external electrodes 56 and 58 and the individual and common wirings 70 and 72 by applying the photosensitive conductive paste, pattern exposure, and development in the same manner as described above. It may be formed on each end face of the piezoelectric member 42 and the substrate 22 so as to serve as a part of the electrical connection path.

In the above-described ink jet head, a piezoelectric member is used as an energy generator for discharging ink droplets. However, the present invention is not limited to this. A method for forming an electrical connection path using a conductive conductor can be applied.

By the way, the method of forming a part of the electric connection path using the photosensitive conductor described above can be widely applied not only to the ink jet head but also to the case where two conductive parts are electrically connected. . For example, as shown in FIG. 9, a first conductive portion 92 patterned on a first substrate 90 and a second substrate 9 adjacent to the first substrate 90 are formed.
4 is to be connected to the second conductive portion 96 formed on the pattern 4. In this case, as shown in FIG. 10, first, a photosensitive conductive paste 98 is applied in a strip shape to the first conductive portion 92, the second conductive portion 96, and the vicinity thereof. Then, only the photosensitive conductive paste 98 in the region connecting the first and second conductive portions 92 and 96 is subjected to pattern exposure using a mask, and the other unexposed portions of the photosensitive conductive paste 98 are developed. Remove. As a result, as shown in FIG. 11, the remaining photosensitive conductor can be used as the connection portion 100 for electrically connecting the first and second conductive portions 92 and 96.

As described above, in the electrical conduction portion using the photosensitive conductor for the connection portion, even if a plurality of conductive portions 92 and 96 to be connected are formed at very narrow intervals, the adjacent connection portion 100 is not required. The connecting portion 100 can be formed accurately, uniformly, and easily so that they do not conduct with each other.

[Brief description of the drawings]

FIG. 1 is a partial plan view of an inkjet head according to a first invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is a side view of the piezoelectric member.

FIG. 5 is a diagram illustrating a manufacturing process of a photosensitive conductor.

FIG. 6 is a diagram illustrating a manufacturing process of the photosensitive conductor, similarly to FIG. 5;

FIG. 7 is a view for explaining a manufacturing process of the photosensitive conductor, similarly to FIGS.

FIG. 8 is a view showing a modified example of the photosensitive conductor.

FIG. 9 is a view for explaining a step of connecting two conductive portions with a photosensitive conductor.

FIG. 10 is a view for explaining a step of connecting two conductive portions with a photosensitive conductor, similarly to FIG. 9;

FIG. 11 is a view similar to FIGS. 9 and 10 for illustrating a step of connecting two conductive portions with a photosensitive conductor.

[Explanation of symbols]

10 inkjet head, 42 piezoelectric member (energy generator), 74, 76 photosensitive conductor, 92 first
, 96 ... second conductive part, 100 ... connection part.

Claims (5)

[Claims] 1. An ink jet head that drives an energy generator by an electric signal to fly ink droplets, wherein at least a part of an electric connection path for applying an electric signal to the energy generator is made of a photosensitive conductor. An ink jet head, characterized in that: 2. The ink jet head according to claim 1, wherein the energy generator is a piezoelectric member. 3. An ink jet head for driving an energy generator of an ink jet head by an electric signal to fly ink droplets, wherein a photosensitive conductive paste is applied to an electrode of the energy generator and the vicinity thereof to correspond to the electrode. After the pattern is exposed to the portion, the photosensitive conductive paste in the unexposed portion is removed by development, and the remaining photosensitive conductor is used as a part of an electrical connection path for applying an electrical signal to the energy generator. Manufacturing method of an inkjet head. 4. An electrically conductive portion comprising a first conductive portion, a second conductive portion, and a connecting portion for electrically connecting both conductive portions, wherein the connecting portion is made of a photosensitive conductor. An electrical conduction part characterized by the above-mentioned. 5. An electrically conductive portion comprising a first conductive portion, a second conductive portion, and a connection portion for electrically connecting both conductive portions, wherein the first and second conductive portions and A photosensitive conductive paste was applied to the vicinity thereof, and the photosensitive conductive paste in a region connecting the first and second conductive portions was subjected to pattern exposure, followed by development to remove the unexposed portion of the photosensitive conductive paste and to remain. A method for manufacturing an electrically conductive portion, wherein the photosensitive conductor is a connecting portion for electrically connecting the first and second conductive portions.