JPH07329295A - Ink jet head and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide an ink jet print head and an ink jet printer in which a multi-nozzle head can be formed without taking a wasteful space between piezoelectric elements and pressure chambers and a driving voltage can be lowered and a head size can be reduced. CONSTITUTION:Pressure chambers 30, 31 formed on a board 10 are formed substantially in a trapezoidal state having a small width at a nozzle forming area 24 side, and further piezoelectric elements 50, 51 disposed on a vibrating plate are also formed substantially in a trapezoidal state to match the shapes of the chambers 30, 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet print head and an ink jet printer used in printers, fax machines, plotters, word processors, etc., and more particularly to a substrate having a plurality of pressure chambers and a plurality of nozzles. The present invention relates to an inkjet printhead having a diaphragm attached to the substrate and a plurality of piezoelectric elements provided on the outer surface of the diaphragm so as to correspond to the plurality of diaphragms, and a printer using the inkjet printhead. is there.

[0002]

2. Description of the Related Art Conventionally, an inkjet printer using an inkjet print head has been known. This ink jet printer has a method of spraying fine particles of ink from the print head without bringing the print head into contact with the print medium. Therefore, there are advantages that the technical limitation of the printing medium is loose and high-speed printing is possible.

FIG. 7 shows the basic principle of a Kaiser type piezoelectric head unit.
The ink supply path 102, the pressure chamber 103, and the nozzle 104 are connected in series. The diaphragm 1 is provided on the surface of the substrate 101.
05 is arranged, and the pressure chamber 1 is provided outside the vibrating plate 105.
The piezoelectric element 106 is provided so as to face the piezoelectric element 1
The signal generation source 10 should be applied to both the front and back sides of 06.
7 is connected. An ink container 109 is connected to the ink supply path 102 via a pipe 108.

In the above structure, when voltage is applied from the signal generation source 107 to the piezoelectric element 106, the piezoelectric element 106
Causes the vibrating plate 105 to bend, and the ink 1 in the pressure chamber 103
10 is ejected from the nozzle 104 as an ink droplet 110a onto a recording medium for recording. Then, when the voltage application to the piezoelectric element 106 is released after the ink is ejected, the diaphragm 1
05 is returned to the original state, and the ejected ink is replenished from the ink container 109 through the ink supply passage 102 and the pipe 108 by the nozzle capillary force.

Here, conventionally, an ink jet print head in which the pressure chambers 36 are arranged in a circular shape as shown in FIG. 9 is known. In the ink jet print head shown in FIG. 9, the common ink path 2 is formed on the substrate 10.
2 is formed in a circular shape, and pressure chambers 36 that store ink from the common ink passage 22 are arranged in a circle inside the common ink passage 22. A total of 48 pressure chambers 36 are provided. The circular arrangement is to increase the nozzle density. Further, each pressure chamber 36 communicates with each ink passage 32, and a nozzle 34 is continuously provided at the tip of each ink passage 32. In the drawing, the ink passages and nozzles extending from each pressure chamber 36 are omitted except for the ink passages 32 and the nozzles 34. A vibrating plate (not shown) is provided on the substrate 10, and piezoelectric elements 52 are arranged on the outer surface of the vibrating plate so as to correspond to the pressure chambers 36.

Further, as shown in FIG.
There is also known an ink jet print head having an elliptical shape. In this case, a common ink passage 22 is formed in an elliptical shape on a substrate 10, and a pressure chamber 36 that stores ink from the common ink passage 22 is formed. It is arranged in an elliptical shape inside the common ink passage 22. The pressure chambers 36 are arranged in an elliptical shape in order to increase the nozzle density and make the lengths of the flow passages from the pressure chambers to the nozzles uniform so that the flow passage resistances are equalized and the variation in the ink ejection amount is eliminated. is there.

In the ink jet print head in which the conventional pressure chamber 36 and the piezoelectric element 52 are arranged in a circular shape or an elliptical shape as described above, as shown in FIGS. 9, 10 and 5 (b), the piezoelectric element is formed. 52 was formed in a substantially rectangular shape. Further, the pressure chamber 36 corresponding to each piezoelectric element 52 is also formed in a rectangular parallelepiped shape. That is, the planar shape of each pressure chamber 36 was rectangular. here,
The shape of each piezoelectric element 52 is substantially the same as that of the corresponding pressure chamber 36, but as shown in FIGS. 9 and 10, it is normally formed to be slightly smaller than the planar shape of the pressure chamber 36.

[0008]

However, in the conventional ink jet print head described above, since the pressure chamber and the piezoelectric element have a rectangular shape, as shown in FIG. 9 and FIG. Then, a wasteful space as shown by reference numeral 70 is generated, and when attempting to increase the number of nozzles in order to increase the dot density, the head size becomes large. In addition, it is desirable that the voltage applied to the piezoelectric element is small in consideration of the manufacturing process such as mounting of IC, radio wave interference, safety, etc. However, if the drive voltage is reduced, the size of the piezoelectric element becomes large, This leads to an increase in head size. Therefore, the head cost increases, and
When installed in a printer, it will increase the dead space.

Therefore, the present invention was created in order to solve the above-mentioned problems, and it is possible to increase the number of nozzles in the head without generating a wasteful space between each piezoelectric element and the pressure chamber. It is an object of the present invention to provide an inkjet print head and an inkjet printer, which can reduce the driving voltage and can reduce the head size, and a method for manufacturing the inkjet print head.

[0010]

According to the present invention, firstly, a plurality of nozzles, a plurality of pressure chambers, an ink flow path connecting the nozzles and the pressure chambers, and ink are supplied to the pressure chambers. A substrate unit having a substrate having an ink supply path and a plate covering at least the pressure chamber is provided, and a plurality of substrate units corresponding to the pressure chambers are provided on a surface of the substrate unit opposite to the nozzle formation surface. In the inkjet print head provided with the piezoelectric element, the plurality of pressure chambers and the piezoelectric element are arranged in a circular shape or an elliptical shape having a center in the nozzle forming area, and the plurality of pressure chambers are provided in the nozzle forming area. The pressure chamber width on one side is formed smaller than the width of the pressure chamber on the side opposite to the nozzle forming region side, and the piezoelectric elements corresponding to the plurality of pressure chambers have a piezoelectric element width on the nozzle forming region side on the nozzle forming region side. Opposition And it is characterized in that it is formed of less than the piezoelectric element width.

Secondly, in the ink jet print head having the above-mentioned first structure, the planar shape of the pressure chamber and the planar shape of the piezoelectric element are substantially trapezoidal. .

Thirdly, in the ink jet print head having the first or second construction, the plate is a vibrating plate.

A fourth feature is that the ink jet printer is equipped with the ink jet print head having the first or second configuration.

Fifth, a plurality of nozzles, a plurality of pressure chambers, an ink flow path connecting the nozzles and the pressure chambers,
A substrate unit having a substrate having an ink supply path for supplying ink to the pressure chamber and a plate covering at least the pressure chamber is provided, and the substrate unit has a surface opposite to the nozzle formation surface. In a method of manufacturing an inkjet printhead in which a plurality of piezoelectric elements are provided corresponding to each pressure chamber, a pressure chamber width on the nozzle formation region side is formed smaller than a pressure chamber width on the opposite side to the nozzle formation region side on a substrate. A step of forming the pressure chamber in a circular shape or an elliptical shape having a center in the nozzle formation region, a step of attaching a plate to the pressure chamber formation side of the substrate, and a PZT provided on the dummy glass are provided on the nozzle formation region side. A step of forming a plurality of piezoelectric elements by patterning a piezoelectric element shape in which the piezoelectric element width is formed smaller than the piezoelectric element width on the side opposite to the nozzle formation side, A step of transferring a plurality of piezoelectric elements on the opposite surface and the nozzle formation face of the serial board unit, is characterized in that it has a.

[0015]

In the ink jet head and the ink jet printer according to the present invention, when printing is performed on the print medium, a driving voltage is applied to the piezoelectric element to selectively excite it and a vibration plate or the like corresponding to the excited piezoelectric element. The vibrating member vibrates and ink is sent from the pressure chamber to the nozzle and ejected from the nozzle.

In the present invention, the plurality of pressure chambers and the piezoelectric element are arranged in a circular shape or an elliptical shape having a center on the nozzle forming region side, and the plurality of pressure chambers are on the nozzle forming region side. The width is formed to be smaller than the pressure chamber width on the side opposite to the nozzle formation region side, and the piezoelectric element corresponding to the plurality of pressure chambers is formed to have the piezoelectric element width on the nozzle formation region side smaller than the piezoelectric element width on the opposite side. Has been done. That is, specifically, the planar shape of the pressure chamber and the planar shape of the piezoelectric element are substantially trapezoidal.

Therefore, it is possible to suppress the wasted space between the pressure chambers and between the piezoelectric elements, the area of the piezoelectric elements can be secured without increasing the length of the piezoelectric elements in the longitudinal direction, and the head can be miniaturized. be able to. Further, since the pressure chambers and the piezoelectric elements are formed in a substantially trapezoidal shape, they can be arranged in a circular shape so as to be densely arranged, so that the number of pressure chambers can be increased and the dot density can be improved even with the same head size. it can.

Further, even if the lengths of the piezoelectric element and the pressure chamber in the longitudinal direction are the same, the width of the planar shape of the piezoelectric element and the pressure chamber can be made large, so that the voltage applied to the piezoelectric element can be reduced.

In the method for manufacturing an ink jet print head of the present invention, the PZT provided on the dummy glass is formed so that the piezoelectric element width on the nozzle forming region side is smaller than the piezoelectric element width on the opposite side to the nozzle forming side. The piezoelectric element shape is patterned to form a plurality of piezoelectric elements, and the plurality of piezoelectric elements are transferred to the surface of the substrate unit opposite to the nozzle forming surface. A piezoelectric element having a shape in which the piezoelectric element width on the nozzle forming side is smaller than the piezoelectric element width on the side opposite to the nozzle forming side is formed corresponding to the shape of the pressure chamber formed smaller than the pressure chamber width on the opposite side. Even in this case, the piezoelectric element can be formed extremely easily.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

Inkjet head A according to the first embodiment
In No. 1, as shown in FIG. 1, the ink path pattern as shown in FIG. 1 is formed on the substrate 10.

That is, the substrate 10 is provided with the ink supply passages 20 at the corners of the substrate 10, and the common ink passages 22 connected to the ink supply passages 20 are formed in a substantially circular shape. Pressure chambers 30 and 31 that store the ink supplied from the common ink passage 22 are connected to the inside of the common ink passage 22. As shown in FIG. 1, the pressure chamber 30 is formed in the same shape, and the pressure chamber 31 at the farthest position from the ink supply passage 20 is formed narrower than the pressure chamber 30. This pressure chamber 3
0 and 31 are arranged in a circle as shown in FIG. 1, and a total of 6
Zero pressure chambers are arranged. Also, this pressure chamber 3
Ink passages 32 are provided in 0 and 31, and nozzles 34 formed in the nozzle forming region 24 are connected to the ink passages 32. In FIG. 1, the nozzle is formed so as to face in the drawing. In FIG. 1, the ink passages and nozzles extending from the pressure chambers 30 and 31 are omitted except for the ink passages 32 and the nozzles 34.

In addition, the ink supply path 20 of the substrate 10 is
A protrusion-shaped guide 26 is provided to prevent the supplied ink from bubbling and to prevent the vibration plate 40 (see FIG. 3) from causing unnecessary vibration. Further, the three directions of the substrate 10 are used for alignment. Alignment marks 28 are provided.

Next, as shown in FIG. 2, the ink jet print head A2 according to the second embodiment is located inside the common ink passage 22 connected from the ink supply passage 20 as in the first embodiment. As in the first embodiment, a plurality of pressure chambers 30 are provided, an ink passage 32 is continuously provided in each pressure chamber 30, and a nozzle 34 is provided at the tip thereof. The second embodiment is different from the first embodiment in that the pressure chambers 30 and 31 are arranged in an elliptical shape, and accordingly, the common ink passage 22 is also formed in an elliptical shape.
It is provided around the.

As shown in FIG. 3, a single vibrating plate 40 is provided on the substrate 10 in the first and second embodiments, and each pressure chamber is placed on the vibrating plate 40. Three
The piezoelectric element 50 is provided corresponding to 0. The piezoelectric element 50 is formed slightly smaller than the planar shape of the pressure chamber 30. The piezoelectric element 51 corresponding to the narrow pressure chamber 31 is formed to be slightly smaller than the planar shape of the pressure chamber 31 in accordance with the size of the pressure chamber 31, as in the case of the piezoelectric element 50.

In this embodiment, as shown in FIG.
A pressure chamber width x1 on the nozzle forming side of the pressure chamber 30 is formed smaller than a pressure chamber width x2 on the opposite side, the pressure chamber 30 has a substantially trapezoidal shape in plan view, and the piezoelectric element 50 corresponding to the pressure chamber 30 is formed. Also in the above, the piezoelectric element width y1 on the nozzle formation side is formed smaller than the piezoelectric element width y2 on the opposite side,
It has a substantially trapezoidal shape as a whole. Specifically, as shown in FIG. 5A, the inner side is 0.6 mm, the outer side is 0.914 mm, and the height in the longitudinal direction is 3.5 mm.

Similarly, the narrow pressure chamber 31 is also formed in a substantially trapezoidal shape, and the piezoelectric element 51 corresponding to the pressure chamber 31 is also formed in a substantially trapezoidal shape in accordance with the planar shape of the pressure chamber 31.

The use condition of this embodiment will be described below.
When printing is performed by the inkjet print head according to this embodiment, a driving voltage is applied to the piezoelectric elements 50 and 51 to selectively excite them, and the excited piezoelectric elements 50 and 51.
The vibrating plate portion corresponding to vibrates and pressure chambers 30 or 3
1 is sent to the nozzle, and ink is ejected from the nozzle.

Here, in the ink jet print head of this embodiment, since the pressure chambers 30 and 31 and the piezoelectric elements 50 and 51 are formed in a substantially trapezoidal shape, useless space can be suppressed and the piezoelectric element Since the area of the piezoelectric element can be secured without increasing the length in the longitudinal direction,
The head can be downsized. In addition, the piezoelectric element 5
Since 0 and 51 have a substantially trapezoidal shape, they can be densely arranged in a circular shape as compared with a rectangular shape. Therefore, in this embodiment, 60 pressure chambers 30 and 31 are arranged in total,
As can be seen from the arrangement of 48 in the conventional example, the number of pressure chambers can be increased and the dot density can be improved even with the same head size.

Furthermore, even if the lengths of the piezoelectric element and the pressure chamber in the longitudinal direction are the same, the width of the planar shape of the piezoelectric element and the pressure chamber can be increased, so that the voltage applied to the piezoelectric element can be reduced. Explaining this point in detail, the amount of vertical change δ when the diaphragm is bent by the application of voltage.
Can be approximated by the following equation.

Δ = αw ² V where α is the displacement coefficient, w is the width of the diaphragm portion occupied by the pressure chamber, and V is the applied voltage. Therefore, by forming the pressure chamber and the piezoelectric element into a substantially trapezoidal shape as in the present embodiment, the outer side can be made large, so that a large up / down change amount can be obtained with the same voltage, and conversely, a small amount. A predetermined amount of vertical change can be obtained with the drive voltage. For example, in the case of the present application shown in FIG. 5A and the conventional case shown in FIG.
The displacement volume is about 1.34 times.

Next, the manufacturing process of the ink jet print head according to this embodiment will be described.

In the manufacturing process of the ink jet print head of this embodiment, the ink path pattern shown in FIG. 1 or 2 is formed on the substrate 10. The formation of this ink path pattern is
The flat substrate is exposed, developed (heat treated), and etched through each step. At that time, the pressure chamber is formed in a substantially trapezoidal shape as shown in FIG. 1 or 2.

Next, the vibrating plate 40 is attached to the ink path pattern forming side of the substrate 10, and then the piezoelectric elements 50 and 51 are formed in the portions of the vibrating plate 40 corresponding to the respective pressure chambers.

Here, in forming the piezoelectric elements 50 and 51, the piezoelectric elements 50 and 51 formed in a substantially trapezoidal shape are attached to the vibration plate 40, but the following sand blasting is used. This facilitates the formation of the piezoelectric element.

That is, an adhesive layer such as wax is formed on a dummy substrate made of glass, and a plate-shaped PZT is formed on the adhesive layer.
Paste. Further, the PZT is covered with a dry film. Then, the dry film is exposed and developed to be patterned, and then the PZT is patterned. In patterning the PZT, a portion other than the piezoelectric element of the PZT is shaved by a so-called sandblasting process in which an abrasive material is accelerated and processed to form a P-shaped piezoelectric element.
Form ZT. After that, the dry film is removed by melting or the like, and an adhesive layer is provided in advance on the diaphragm.
The piezoelectric element-shaped PZT is transferred onto the diaphragm. By the above, even if the piezoelectric element has a substantially trapezoidal shape instead of a rectangular shape as in the present application, the piezoelectric element can be easily formed, and the piezoelectric element shape is made substantially trapezoidal. Is never difficult.

In the above example, the dry film covered with PZT is patterned, but the dry film is patterned in another step, the patterned dry film is transferred to PZT, and thereafter,
There is also a method of patterning PZT. Further, the patterning of the PZT has been described as being performed by sandblasting, but it may be performed by etching or laser cutting. However, if the PZT is patterned by etching, the shape of each piezoelectric element may become incomplete and there is a possibility of short-circuiting between the piezoelectric elements, so sandblasting is desirable.

Further, as shown in FIG. 6, the piezoelectric element 50 may have a planar shape substantially close to a triangle. Further, in the above description, the configuration in which the vibrating plate 40 is attached to the ink path pattern forming side of the substrate 10 and the piezoelectric element 50 is arranged on the vibrating plate 40 has been described. A case where a piezoelectric element is attached on the side opposite to the formation side is also conceivable. In this case, the nozzle is provided on the surface opposite to the piezoelectric element formation side. In this case, it is required that the distance between the bottom of the groove that forms the pressure chamber and the outer surface on which the piezoelectric element is provided be short to some extent.

Further, in the printer using the ink jet print head having the above construction, as shown in FIG. 8, the cartridge 150 arranged on the carriage 151.
An ink jet print head is disposed inside, and a carriage 151 is slidably provided on two guides 152, and a pulley 154 driven by a motor 153 is provided.
Rotation causes the wire 155 to move left and right, and the carriage 151 moves left and right in accordance with the movement of the wire 155. Ink ejection control of the inkjet print head is performed by a drive control unit (not shown) via a flexible cable. On the print side of the cartridge 150,
The paper 160 wound around the platen 157 faces each other,
Printing is performed on the paper 160.

[0040]

As described above, in the present invention, the plurality of pressure chambers and the piezoelectric element are arranged in a circular shape or an elliptical shape having the center in the nozzle forming region, and the plurality of pressure chambers are The pressure chamber width on the nozzle formation region side is formed to be smaller than the pressure chamber width on the opposite side to the nozzle formation side, and the piezoelectric elements corresponding to the plurality of pressure chambers are piezoelectric elements on the opposite side of the piezoelectric element width on the nozzle formation side. Since it is formed smaller than the element width, it is possible to suppress the wasted space between the pressure chambers and between the piezoelectric elements, it is possible to secure the area of the piezoelectric element without increasing the length of the piezoelectric element in the longitudinal direction, The head can be downsized. In addition, since the pressure chambers and the piezoelectric elements are formed in a substantially trapezoidal shape, they can be densely arranged in a circular shape, so that the dot density can be improved.

Furthermore, even if the lengths of the piezoelectric element and the pressure chamber in the longitudinal direction are the same, the width of the piezoelectric element and the pressure chamber in plan view can be made large, so that the voltage applied to the piezoelectric element can be reduced.

Further, in the method for manufacturing an ink jet print head according to the present invention, the nozzle has a width corresponding to the shape of the pressure chamber formed on the side where the nozzle is formed smaller than the width on the side opposite to the side where the nozzle is formed. Even when forming a piezoelectric element having a shape in which the width of the piezoelectric element on the formation side is smaller than the width of the piezoelectric element on the side opposite to the nozzle formation side, the piezoelectric element can be formed extremely easily.

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration of a substrate of an inkjet print head in an embodiment according to the present invention.

FIG. 2 is a plan view showing a configuration of a substrate of an inkjet print head in an example according to the present invention.

FIG. 3 is a cross-sectional view showing a configuration of an inkjet print head in an embodiment according to the present invention.

FIG. 4 is an explanatory diagram showing a configuration of a pressure chamber and a piezoelectric element in an inkjet printhead according to an embodiment of the present invention.

5A and 5B are explanatory views showing the shape of the piezoelectric element, and FIG. 5A is an explanatory view showing the shape of the piezoelectric element in the present embodiment,
(B) is an explanatory view showing a shape of a conventional piezoelectric element.

FIG. 6 is a plan view showing another shape of the piezoelectric element.

FIG. 7 is a diagram illustrating the principle of a piezoelectric head unit.

FIG. 8 is a perspective view of a main part of a printer including the inkjet print head according to the present embodiment.

FIG. 9 is a plan view showing a configuration of a substrate of a conventional inkjet printhead.

FIG. 10 is a plan view showing a configuration of a substrate of a conventional inkjet printhead.

[Explanation of symbols]

 10 Substrate 20 Ink Supply Channel 22 Common Ink Channel 24 Nozzle Forming Area 26 Guide 28 Alignment Mark 30, 31 Pressure Chamber 40 Vibration Plate 50, 51 Piezoelectric Element

Claims (5)

[Claims] 1. A substrate having a plurality of nozzles, a plurality of pressure chambers, an ink flow path connecting the nozzles and the pressure chambers, and an ink supply path for supplying ink to the pressure chambers; An ink jet print head comprising: a substrate unit having a plate covering the chamber; and a plurality of piezoelectric elements corresponding to the pressure chambers on a surface of the substrate unit opposite to the nozzle forming surface, The plurality of pressure chambers and the piezoelectric element are arranged in a circular shape or an elliptical shape having a center in the nozzle formation region, and the plurality of pressure chambers have a pressure chamber width on the nozzle formation region side opposite to the nozzle formation region side. Of the pressure chambers, and the piezoelectric elements corresponding to the plurality of pressure chambers are formed such that the piezoelectric element width on the nozzle formation region side is smaller than the piezoelectric element width on the side opposite to the nozzle formation region side. Inkjet printhead according to claim Rukoto. 2. The ink jet print head according to claim 1, wherein the planar shape of the pressure chamber and the planar shape of the piezoelectric element are substantially trapezoidal. 3. The ink jet print head according to claim 1, wherein the plate is a vibration plate. 4. An ink jet printer comprising the ink jet print head according to any one of claims 1 to 3. 5. A substrate having a plurality of nozzles, a plurality of pressure chambers, an ink flow path connecting the nozzles and the pressure chambers, and an ink supply path for supplying ink to the pressure chambers, and at least the pressure A method of manufacturing an ink jet print head, comprising a substrate unit having a plate that covers the chamber, and a plurality of piezoelectric elements corresponding to the pressure chambers are provided on a surface of the substrate unit opposite to the nozzle formation surface. In the step of forming a pressure chamber in the substrate in which the width of the pressure chamber on the nozzle formation region side is smaller than the width of the pressure chamber on the side opposite to the nozzle formation region side in a circular or elliptical shape having a center in the nozzle formation region, The step of attaching the plate to the pressure chamber forming side of the substrate, and the PZT provided on the dummy glass, the piezoelectric element width on the nozzle forming region side is opposite to the nozzle forming side. And a step of forming a plurality of piezoelectric elements by patterning into a smaller piezoelectric element shape, and a step of transferring the plurality of piezoelectric elements to a surface of the substrate unit opposite to the nozzle formation surface. A method for manufacturing an inkjet printhead, comprising: