JP2004114519A - Ink jet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet head in which unaltered ink ejection can be sustained without being affected by an adjacent ejection channel. <P>SOLUTION: A plurality of ink pressure chambers are arranged contiguously to each other in matrix on a cavity plate. Two groove through parts formed, respectively, in a first manifold plate, a second manifold plate and a third manifold plate 500 define two manifold channels 2. The two manifold channels 2 communicate with all through holes made in the upper or lower half section of a supply plate in the longitudinal direction and thereby communicate with all through holes made in the upper or lower half section of the cavity supply plate in the longitudinal direction. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inkjet head having an ink manifold flow path.
[0002]
[Prior art]
In one of the conventional inkjet heads, as shown in FIG. 34, a flow path forming plate 1012 has a through hole formed in a silicon substrate having a thickness of about 400 μm by wet etching or the like. Accordingly, a common ink chamber 1026, an ink supply path 1027 formed elongated from the common ink chamber 1026 to a position overlapping the nozzle opening 1013 of the nozzle plate, and a pressure chamber 1020 are configured.
[0003]
Since the ink supply pipe 1035 communicates with one end of the common ink chamber 1026, the width of the ink supply path 1027 communicating with the other end of the ink supply pipe 1035 is remote from the ink supply pipe 1035. That is, the nozzle number is gradually widened from # 4 to # 1. In other words, the width of the common ink chamber 1026 gradually increases from the center to the front end.
[0004]
In this regard, since the depth of the common ink chamber 1026 formed in the flow path forming plate 1012 is uniform, the cross-sectional area of the inlet (the supply port corresponding to # 1 to # 4) of the ink supply path 1027 is gradually increased. That is, it is said that fluctuations in the speed and the ink amount that occur in the nozzle numbers # 1 to # 4 can be suppressed (for example, see Patent Document 1).
[0005]
[Patent Document 1]
JP 2001-277496A (Pages 5-6, FIG. 4)
[0006]
[Problems to be solved by the invention]
However, since the common ink chamber 1026 is at the end of one-way traffic to the other end far away from the ink supply pipe 1035, the ink generated when ink is ejected from the nozzle opening 1013 of a certain nozzle number. The meniscus in the nozzle opening 1013 of another nozzle number adjacent to the nozzle number is broken by the pressure wave inside, and air enters from there, and the nozzle openings 1013 of other nozzle numbers adjacent to the nozzle number are sequentially opened. However, there is a possibility that a failure may occur.
[0007]
In view of the above, an object of the present invention is to provide an inkjet head that maintains stable ink ejection without being affected by an adjacent ejection channel.
[0008]
[Means for Solving the Problems]
The invention according to claim 1, which has been made to solve this problem, is directed to a cavity plate in which a plurality of ink pressure chambers are arranged adjacent to each other in a matrix, and an ink communicating with a group of ink pressure chambers of the cavity plate. A manifold plate having a manifold flow path formed therein, wherein the ink manifold flow path of the manifold plate is formed in a closed loop shape.
[0009]
In the ink jet head of the present invention having such features, the plurality of ink pressure chambers are arranged in the cavity plate in a matrix adjacent to each other, and the ink manifold flow path communicating with a group of the ink pressure chambers of the cavity plate is provided with a manifold. Formed on the plate. Therefore, a large number of ejection channels passing through one ink pressure chamber communicate with the ink manifold flow path of the manifold plate, but this is because the ink manifold flow path of the manifold plate is formed in a closed loop shape. Even if ink is ejected in the ejection channel passing through the ink pressure chamber and a pressure wave is generated in the ink in the ink manifold flow path, this pressure wave only propagates by turning through the loop-shaped ink manifold flow path. Therefore, the meniscus in the discharge channel passing through another ink pressure chamber adjacent to the ink pressure chamber is not broken, and air does not enter therefrom.
[0010]
That is, in the ink jet head of the present invention, since the ink manifold flow path of the manifold plate is formed in a closed loop, ink is discharged in a discharge channel passing through a certain ink pressure chamber, and ink inside the ink manifold flow path is formed. Even if a pressure wave is generated, the pressure wave simply propagates by turning around the loop-shaped ink manifold flow path, causing a meniscus in a discharge channel passing through another ink pressure chamber adjacent to the ink pressure chamber. Since the ink is not broken and air does not enter therefrom, it can be said that the ink is not affected by the adjacent discharge channels and the stable ink discharge is maintained.
[0011]
According to a second aspect of the present invention, there is provided the ink jet head according to the first aspect, wherein the supply plate is provided on the manifold plate and provided with an ink supply port communicating with an ink manifold channel of the manifold plate. And two or more ink supply ports of the supply plate are provided.
[0012]
That is, in the ink jet head of the present invention, a supply plate provided with an ink supply port laminated on the manifold plate and communicating with the ink manifold flow path of the manifold plate is provided, and two or more ink supply ports of the supply plate are provided. For example, even if one of the ink supply ports of the supply plate is clogged, the ink can be supplied from the other ink supply port of the supply plate to the ink manifold flow path of the manifold plate, so that a more stable ink can be supplied. Discharge can be maintained.
[0013]
The invention according to claim 3 is the inkjet head according to claim 1 or 2, wherein the manifold plate includes a floating island portion surrounded by an ink manifold flow path of the manifold plate, and the manifold plate. And a connecting piece that supports the floating island portion of (a), the connecting piece of the manifold plate is formed by half-etching the manifold plate.
[0014]
That is, in the ink jet head of the present invention, the manifold plate includes a floating island portion surrounded by the ink manifold flow path of the manifold plate, and a connecting piece that supports the floating island portion of the manifold plate, and half-etches the manifold plate. By forming the connecting piece of the manifold plate by this, if the ink manifold flow path of the manifold plate is formed in a closed loop, the ink manifold flow path of the manifold plate is above or below the connecting piece of the half-etched manifold plate. Thus, it can be said that a structure is created in which the pressure wave generated in the ink easily propagates while turning, since the ink can freely flow around the floating island portion of the manifold plate.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, a schematic configuration of the inkjet head of the present embodiment will be described.
As shown in FIG. 1, the ink-jet head 1 has a structure in which a plurality of thin metal plates formed in a substantially rectangular shape are laminated, and further, four plate-shaped piezoelectric sheets 10 each having a substantially trapezoidal shape in a plan view are alternated. Are laminated. An extension 51 of a flexible printed circuit board (hereinafter, referred to as “FPC board”) 50 is placed on the upper side of each piezoelectric sheet 10 and is electrically connected as described later. An ink supply port 901 is provided around each of the stacked piezoelectric sheets 10.
[0016]
Here, the laminated structure of the ink jet head 1 will be specifically described. It has a nine-layer structure in which nine substantially rectangular thin metal plates are laminated, and as shown in FIGS. 100, a cover plate 200, a first manifold plate 300, a second manifold plate 400, a third manifold plate 500, a supply plate 600, an aperture plate 700, a base plate 800, and a cavity plate 900.
[0017]
In this regard, as shown in FIG. 2, the nozzle plate 100 includes four areas 110 each having a substantially trapezoidal shape in a plan view as a group, and as shown in FIG. A large number of holes are provided corresponding to the required printing density.
[0018]
On the upper side of the cover plate 200, as shown in FIG. 2, four substantially trapezoidal regions 210 in a plan view are grouped together, and as shown in FIG. Many are drilled. Each of the through holes 211 of the cover plate 200 is disposed at a position facing each of the nozzles 111 of the nozzle plate 100. When the cover plate 200 and the nozzle plate 100 are stacked, It communicates with the nozzle 111 (see FIG. 27).
[0019]
As shown in FIG. 5, two groove recesses 212 are formed in the longitudinal direction below the cover plate 200. Each through hole 211 is provided on the outer periphery of the groove recessed portion 212 and on the plurality of floating island portions 213 surrounded by the groove recessed portion 212.
[0020]
As shown in FIG. 6, the first manifold plate 300 is provided with a large number of through holes 311 for a small diameter ink passage. Each of the through holes 311 of the first manifold plate 300 is provided at a position facing each of the through holes 211 of the cover plate 200. When the first manifold plate 300 and the cover plate 200 are stacked, It communicates with each through hole 211 of the cover plate 200 (see FIG. 27).
[0021]
Further, in the first manifold plate 300, as shown in FIG. 6, two groove through portions 312 constituting the ink manifold flow path 2 (see FIG. 27) are formed in the longitudinal direction. Each through hole 311 is provided on the outer periphery of the groove penetrating portion 312 and on the plurality of floating islands 313 surrounded by the groove penetrating portion 312. The plurality of floating islands 313 have a structure supported by a plurality of connecting pieces 314 whose lower sides are half-etched. Each connecting piece 314 is formed with a thickness of about half of the first manifold plate 300.
In addition, a plurality of ink supply units 315 extend from the groove penetration unit 312.
[0022]
As shown in FIG. 7, the second manifold plate 400 has a large number of through holes 411 for ink passages having a small diameter. Each through-hole 411 of the second manifold plate 400 is disposed at a position facing each of the through-holes 311 of the first manifold plate 300, and the second manifold plate 400 and the first manifold plate 300 are stacked. Then, it communicates with each through-hole 311 of the first manifold plate 300 (see FIG. 27).
[0023]
Further, in the second manifold plate 400, as shown in FIG. 7, two groove through portions 412 constituting the ink manifold flow path 2 (see FIG. 27) are formed in the longitudinal direction. And each groove penetration part 412 of the second manifold plate 400 is arranged at a position facing each groove penetration part 312 of the first manifold plate 300, and the second manifold plate 400 and the first manifold plate 300 are When they are stacked, they communicate with the groove penetrations 312 of the first manifold plate 300 (see FIG. 27). Each through-hole 411 is provided on the outer periphery of the groove penetrating part 412 and on the plurality of floating island parts 413 surrounded by the groove penetrating part 412. The plurality of floating island portions 413 have a structure supported by a plurality of connecting pieces 414 whose upper sides are half-etched. Each connecting piece 414 is formed with a thickness of about half of the second manifold plate 400.
Further, a plurality of ink supply portions 415 extend from the groove penetration portion 412. Each ink supply unit 415 of the second manifold plate 400 is disposed at a position facing each ink supply unit 315 of the first manifold plate 300, and the second manifold plate 400 and the first manifold plate 300 When they are stacked, they communicate with the respective ink supply units 315 of the first manifold plate 300 (see FIG. 27).
[0024]
As shown in FIG. 8, the third manifold plate 500 is provided with a large number of through holes 511 for a small diameter ink passage. And each through-hole 511 of the third manifold plate 500 is disposed approximately at a position facing each of the through-holes 411 of the second manifold plate 400, and the third manifold plate 500 and the second manifold plate 400 are When they are stacked, they communicate with the through holes 411 of the second manifold plate 400 (see FIG. 27).
[0025]
Further, in the third manifold plate 500, as shown in FIG. 8, two groove through portions 512 forming the ink manifold flow path 2 (see FIG. 27) are formed in the longitudinal direction. And each groove penetration part 512 of the third manifold plate 500 is arranged at a position facing each groove penetration part 412 of the second manifold plate 400, and the third manifold plate 500 and the second manifold plate 400 When they are stacked, they communicate with the respective groove penetration portions 412 of the second manifold plate 400 (see FIG. 27). Each through-hole 511 is provided on the outer periphery of the groove penetrating portion 512 and on the plurality of floating island portions 513 surrounded by the groove penetrating portion 512. The plurality of floating islands 513 have a structure supported by a plurality of connecting pieces 514 whose upper sides are half-etched. Each connecting piece 514 is formed with a thickness of about half of the third manifold plate 500.
Further, a plurality of ink supply units 515 extend from the groove penetrating portion 512. Each ink supply unit 515 of the third manifold plate 500 is disposed at a position facing each ink supply unit 415 of the second manifold plate 400, and the third manifold plate 500 and the second manifold plate 400 When they are stacked, they communicate with the respective ink supply units 415 of the second manifold plate 400 (see FIG. 27).
[0026]
Further, the supply plate 600 has four trapezoidal regions 610 each having a substantially trapezoidal shape in a plan view as shown in FIG. 2, and a large number of through holes 611 for ink passages having a small diameter as shown in FIG. In addition, a large number of through holes 612 for introducing ink having a small diameter are provided. In this regard, the respective through holes 611 of the supply plate 600 are disposed approximately at positions facing the respective through holes 511 of the third manifold plate 500, and the supply plate 600 and the third manifold plate 500 are stacked. At this time, it communicates with each through hole 511 of the third manifold plate 500 (see FIG. 27). On the other hand, each through hole 612 of the supply plate 600 is disposed at a position facing one of the two groove penetration portions 512 of the third manifold plate 500, and the supply plate 600 and the third manifold plate 500 are stacked. Then, it communicates with one of the two groove penetration portions 512 of the third manifold plate 500 (see FIG. 27). As shown in FIGS. 10 and 11, a large number of filter holes 613 are formed in each through hole 612 of the supply plate 600 to prevent dust in the ink from entering.
[0027]
Further, as shown in FIGS. 2 and 9, the supply plate 600 has ten small diameter ink supply ports 601 for supplying ink outside the four trapezoidal regions 610 in plan view. . Each of the ink supply ports 601 of the supply plate 600 is disposed at a position facing each of the ink supply portions 515 of the third manifold plate 500, and when the supply plate 600 and the third manifold plate 500 are stacked. Then, it communicates with each ink supply unit 515 of the third manifold plate 500 (see FIG. 27). As shown in FIG. 16, a large number of filter holes 602 for preventing dust in the ink from entering are provided in each of the ink supply ports 601 of the supply plate 600.
[0028]
As shown in FIG. 2, the aperture plate 700 has a group of four trapezoidal regions 710 each having a substantially trapezoidal shape in plan view, and as shown in FIG. In addition to the perforations, a large number of aperture portions 712 for introducing minute ink are provided. Each of the through holes 711 of the aperture plate 700 is disposed roughly at a position facing each of the through holes 611 of the supply plate 600. When the aperture plate 700 and the supply plate 600 are stacked, the supply plate It communicates with each through-hole 611 of 600 (see FIG. 27).
[0029]
On the other hand, as shown in FIG. 13, each aperture portion 712 of the aperture plate 700 includes an ink inlet 713, an ink outlet 714, and a groove penetrating portion 715 for communicating the ink inlet 713 with the ink outlet 714. They are formed by pressing. Further, the ink inlets 713 of the respective throttle portions 712 of the aperture plate 700 are disposed approximately at positions facing the respective through holes 612 of the supply plate 600, and when the aperture plate 700 and the supply plate 600 are stacked. Then, it communicates with each through hole 612 of the supply plate 600 (see FIG. 27).
[0030]
Further, in the aperture plate 700, as shown in FIGS. 2 and 12, ten small-diameter ink supply ports 701 for supplying ink are formed outside the four trapezoidal regions 710 in plan view. . Each ink supply port 701 of the aperture plate 700 is disposed at a position opposite to each ink supply port 601 of the supply plate 600. When the aperture plate 700 and the supply plate 600 are stacked, the supply plate It communicates with each of the ink supply ports 601 (see FIG. 27).
[0031]
Further, as shown in FIG. 2, the base plate 800 has a group of four substantially trapezoidal regions 810 as viewed in plan, and as shown in FIG. A large number of through holes 812 for introducing ink having a small diameter are provided. Each of the through holes 811 of the base plate 800 is disposed approximately at a position facing each of the through holes 711 of the aperture plate 700. When the base plate 800 and the aperture plate 700 are stacked, the It communicates with each through hole 711 (see FIG. 27). On the other hand, each through-hole 812 of the base plate 800 is disposed roughly at a position facing the ink outlet 714 of each of the aperture portions 712 of the aperture plate 700, and when the base plate 800 and the aperture plate 700 are stacked, It communicates with the ink outlets 714 of each of the aperture portions 712 of the aperture plate 700 (see FIG. 27).
[0032]
Further, as shown in FIGS. 2 and 14, the base plate 800 is provided with ten small-diameter ink supply ports 801 for ink supply outside the four trapezoidal regions 810 in plan view. Each ink supply port 801 of the base plate 800 is disposed at a position facing each ink supply port 701 of the aperture plate 700. When the base plate 800 and the aperture plate 700 are stacked, the It communicates with each ink supply port 701 (see FIG. 27).
[0033]
Further, the cavity plate 900 is required to have a substantially rhombic ink pressure chamber 911 as shown in FIG. 15 by grouping four regions 910 each having a substantially trapezoidal shape in plan view, as shown in FIG. A large number of them are provided in a matrix in accordance with the printing density. In this regard, the ink pressure chambers 911 of the cavity plate 900 are arranged at a high density between the acute angles of the other adjacent ink pressure chambers 911 such that the acute angles of the ink pressure chambers 911 enter. . One acute angle portion of each of the ink pressure chambers 911 of the cavity plate 900 is disposed approximately at a position facing each of the through holes 811 of the base plate 800. When the cavity plate 900 and the base plate 800 are stacked, Then, it communicates with each through hole 811 of the base plate 800 (see FIG. 27). On the other hand, the other acute angle portion of each of the ink pressure chambers 911 of the cavity plate 900 is disposed approximately at a position facing each of the through holes 812 of the base plate 800, and when the cavity plate 900 and the base plate 800 are stacked. Then, it communicates with each through hole 812 of the base plate 800 (see FIG. 27).
[0034]
Further, as shown in FIGS. 2 and 15, the cavity plate 900 is provided with ten small-diameter ink supply ports 901 outside the four trapezoidal regions 910 in plan view. Each ink supply port 901 of the cavity plate 900 is disposed at a position facing each ink supply port 801 of the base plate 800. When the cavity plate 900 and the base plate 800 are stacked, each ink supply port 901 of the base plate 800 It communicates with the ink supply port 801 (see FIG. 27).
[0035]
As shown in FIGS. 2 and 15, the cavity plate 900 is provided with positioning holes 903 used for laminating the piezoelectric sheets 10 on both sides of four regions 910 having a substantially trapezoidal shape in plan view. .
[0036]
Next, a schematic structure of the piezoelectric sheet 10 and the FPC board 50 and an electrical connection structure between the piezoelectric sheet 10 and the FPC board 50 will be described.
First, the schematic structure of the piezoelectric sheet 10 will be described. As shown in FIG. 17, a large number of substantially rhombus-shaped drive electrodes 11 are formed in a matrix on the piezoelectric sheet 10 in accordance with the required printing density. Have been. Each drive electrode 11 of the piezoelectric sheet 10 is disposed roughly at a position facing each ink pressure chamber 911 of the cavity plate 900, and the piezoelectric sheet 10 is laminated on the cavity plate 900 When the upper surface of the ink pressure chamber 911 is closed by the piezoelectric sheet 10, it is located on the upper surface of each ink pressure chamber 911 of the cavity plate 900.
[0037]
Also, as shown in FIGS. 18 and 19, each drive electrode 11 of the piezoelectric sheet 10 has a contact land portion 14 formed on a portion drawn from its acute angle portion. The contact land portion 14 of each drive electrode 11 has a two-stage shape having a first step surface 12 and a second step surface 13.
[0038]
As shown in FIG. 19, the piezoelectric sheet 10 has a structure in which a first piezoelectric layer 21, a second piezoelectric layer 23, a third piezoelectric layer 24, and a fourth piezoelectric layer 26 are laminated. An internal electrode 22 is formed between the layer 21 and the second piezoelectric layer 23, and an internal electrode 25 is formed between the third piezoelectric layer 24 and the fourth piezoelectric layer 26. In this regard, the ends of the internal electrodes 22 and 25 are formed so as to be exposed at the end surfaces of both oblique sides of the piezoelectric sheet 10 (see FIGS. 1 and 17). Note that, when the piezoelectric sheets 10 are stacked on the cavity plate 900, the end faces of both oblique sides of each piezoelectric sheet 10 come into contact with the end faces of both oblique sides of another adjacent piezoelectric sheet 10, so that When the sheet 10 is stacked on the cavity plate 900, the internal electrodes 22, 25 of each piezoelectric sheet 10 are electrically connected.
[0039]
As shown in FIG. 17, two types of common electrodes 31 and 36 are alternately formed on the edges of both oblique sides of the piezoelectric sheet 10. The one common electrode 31 is electrically connected to the internal electrode 25 formed between the third piezoelectric layer 24 and the fourth piezoelectric layer 26 through the through hole 32 as shown in FIG. I have. The other common electrode 36 is electrically connected to the internal electrode 22 formed between the first piezoelectric layer 21 and the second piezoelectric layer 23 via a through hole 37 as shown in FIG. I have. As shown in FIG. 20, a convex contact land 33 is formed on one common electrode 31. Similarly, on the other common electrode 36, as shown in FIG. 21, a convex contact land portion 38 is formed.
[0040]
Further, in the piezoelectric sheet 10, as shown in FIG. 17, a plurality of circular dummy electrodes 41 are formed on the virtual lines L1 and L2 at the edges of the parallel opposing sides (upper side and lower side). In this respect, each dummy electrode 41 is different from the common electrodes 31 and 36 described above, and is not electrically connected to any of the internal electrodes 22 and 25 as shown in FIG.
[0041]
Note that, as shown in FIG. 17, the piezoelectric sheet 10 is provided with positioning marks 46 used when the FPC board 50 is placed on the edges of both oblique sides.
[0042]
Next, the schematic structure of the FPC board 50 will be described. In the FPC board 50, as shown in FIG. Each contact land portion 52 of the FPC board 50 is disposed at a position facing the second step surface 13 of the contact land portion 14 of each drive electrode 11 of the piezoelectric sheet 10. Is placed on the second step surface 13 of the contact land portion 14 of each drive electrode 11 of the piezoelectric sheet 10. Further, on each contact land portion 52 of the FPC board 50, although not shown in FIG. 23, a conductor pattern 53 made of copper foil is wired as shown in FIG.
[0043]
Further, in the FPC board 50, as shown in FIG. 23, a large number of contact lands 54 are also formed on the upper side of the extension part 51 and the edges of both oblique sides. Each of the contact land portions 54 on the upper edge of the extension portion 51 faces the dummy electrode 41 formed on the virtual line L1 (see FIG. 17) on the upper edge of the piezoelectric sheet 10. When the FPC board 50 is placed on the piezoelectric sheet 10, each dummy electrode 41 formed on the virtual line L <b> 1 (see FIG. 17) at the upper edge of the piezoelectric sheet 10. Contact The contact land portions 54 on both oblique sides of the extension portion 51 face the contact land portions 33 and 38 of the two types of common electrodes 31 and 36 formed alternately on the edges of both oblique sides of the piezoelectric sheet 10. When the FPC board 50 is mounted on the piezoelectric sheet 10, the two types of common electrodes 31, 36 alternately formed on both oblique sides of the piezoelectric sheet 10 are disposed. It contacts the contact land portions 33 and 38. Further, although not shown in FIG. 23, a conductor pattern 55 made of copper foil is wired on each contact land portion 54 of the FPC board 50, as shown in FIG. Each contact land 54 is electrically connected.
[0044]
As shown in FIG. 25, the FPC board 50 includes a base film 61 such as a polyimide film, and the above-described conductor pattern 53, cover coat 62, Ni plating 63, solder 64, and the like. In this regard, the Ni plating 63 and the solder 64 constitute each contact land portion 52 of the FPC board 50. The structure shown in FIG. 25 is the same for the contact land portions 54 and the conductor patterns 55 formed and wired on the upper side of the extension portion 51 and the edges of both oblique sides.
[0045]
Further, on the FPC board 50, as shown in FIG. 23, positioning marks 56 used when the FPC board 50 is placed on the piezoelectric sheet 10 are provided on both oblique sides.
[0046]
Therefore, when the positioning mark 56 of the FPC board 50 and the positioning mark 46 of the piezoelectric sheet 10 are overlapped and the FPC board 50 is placed on the piezoelectric sheet 10, each contact land portion 52 of the FPC board 50 is As shown in FIG. 26, if the heat contact bonding is performed by thermocompression bonding or the like, the Ni plating 63 of the FPC board 50 and the contact land portion 14 of the piezoelectric sheet 10 overlap with the second step surface 13 of the contact land portion 14 of the electrode 11. Since the second step surfaces 13 are fixed in contact with each other, the respective conductor patterns 53 of the FPC board 50 and the respective drive electrodes 11 of the piezoelectric sheet 10 are electrically connected.
[0047]
At this time, as shown in FIG. 26, the N.V. applied to the second step surface 13 of the contact land portion 14 of each drive electrode 11 of the piezoelectric sheet 10. C. The P15 covers the Ni plating 63 of the FPC board 50 and the second step surface 13 of the contact land 14 of the piezoelectric sheet 10, but the second step 13 of the contact land 14 of each drive electrode 11 of the piezoelectric sheet 10. It may hang down to the surface 12.
[0048]
When the positioning mark 56 of the FPC board 50 and the positioning mark 46 of the piezoelectric sheet 10 are overlapped and the FPC board 50 is placed on the piezoelectric sheet 10, each contact land 54 of the FPC board 50 further The dummy electrodes 41 formed on the imaginary line L1 (see FIG. 17) at the upper edge of the dummy electrode 41, or the two types of common electrodes 31 and 36 alternately formed at the two oblique edges of the piezoelectric sheet 10. Since they overlap with the contact land portions 33 and 38, they are electrically connected to the respective dummy electrodes 41 or the two types of common electrodes 31 and 36 by heat bonding such as thermocompression bonding.
[0049]
Therefore, if a drive voltage is applied between the drive electrode 11 and the internal electrodes 22 and 25 via the FPC board 50, the first piezoelectric layer 21 of the piezoelectric sheet 10 located immediately below the drive electrode 11 and The second piezoelectric layer 23, the third piezoelectric layer 24, and the fourth piezoelectric layer 26 can be deformed.
[0050]
That is, the portion of the first piezoelectric layer 21 located directly below the drive electrode 11 constitutes an active portion that bends when a voltage is applied. When the first piezoelectric layer 21, the second piezoelectric layer 23, the third piezoelectric layer 24, and the fourth piezoelectric layer 26 are fired, the shrinkage ratio of the piezoelectric ceramic and the metal material constituting the electrodes is reduced when fired. Since they are different, the entire piezoelectric sheet 10 may warp or undulate. Therefore, after firing, the internal electrodes 25 formed on the upper surface of the fourth piezoelectric layer 26 are warped by the first piezoelectric layer 21, the second piezoelectric layer 23, the third piezoelectric layer 24, and the fourth piezoelectric layer 26. Alternatively, it functions as a constraining layer for preventing the planarity from being impaired by waving. Further, the second piezoelectric layer 23, the third piezoelectric layer 24, and the fourth piezoelectric layer 26 are restrained so that the active portion of the first piezoelectric layer 21 is deformed only downward (toward the cavity plate 900). Functions as a layer.
[0051]
Next, the flow of ink in the inkjet head 1 configured as described above will be described. As shown in FIG. 1, from the lower layer, a nozzle plate 100, a cover plate 200, a first manifold plate 300, a second manifold plate 400, a third manifold plate 500, a supply plate 600, an aperture plate 700, a base plate 800, a cavity plate When the piezoelectric sheet 900 and the piezoelectric sheet 10 are stacked, the flow path of the ink ejected from one nozzle 111 of the nozzle plate 100 can be shown in the cross-sectional view of FIG. FIG. 28 is a perspective view showing a part of a flow path of ink ejected from one nozzle 111 of the nozzle plate 100.
[0052]
In this regard, ink ejected from one nozzle 111 of the nozzle plate 100 is first supplied to the ink manifold channel 2 from an ink tank (not shown). In order to supply ink to the ink manifold channel 2 from an ink tank (not shown), although not shown in FIGS. 27 and 28, an ink supply port 901 (see FIG. 1) of the cavity plate 900 and The ink supply port 801 of the base plate 800 (see FIG. 1), the ink supply port 701 of the aperture plate 700 (see FIG. 1), the ink supply port 601 of the supply plate 600 (see FIG. 1), and the groove penetrating portion of the third manifold plate 500. The ink supply unit 515 of the second manifold plate 400 (see FIG. 7), the ink supply unit 415 of the groove through portion 412 of the second manifold plate 400 (see FIG. 7), and the ink supply unit 315 of the groove through portion 312 of the first manifold plate 300 (see FIG. 8). 6) is performed via an ink supply path that communicates with the other. At this time, when ink passes through the ink supply port 601 of the supply plate 600, the filter holes 602 (see FIG. 16) prevent dust from entering the ink.
[0053]
Here, the schematic configuration of the ink manifold flow path 2 will be described. As shown in FIG. 27, the ink manifold flow path 2 includes a groove penetrating portion 512 (see FIG. 8) of the third manifold plate 500 and a second manifold plate. The side wall surface is formed by communication between the groove penetration portion 412 (see FIG. 7) of the first manifold plate 300 and the groove penetration portion 312 (see FIG. 6) of the first manifold plate 300, and the upper wall surface is constituted by the supply plate 600. The lower wall surface is constituted by the cover plate 200.
[0054]
As shown in FIG. 30, two ink manifold channels 2 are formed. That is, as shown in FIG. 31, one ink manifold channel 2 is formed in the upper half of the longitudinal direction, and as shown in FIG. 32, one ink manifold channel 2 is formed in the lower half of the longitudinal direction. Have been. Each ink manifold channel 2 has an ink supply portion 515 (see FIG. 8) of the groove penetration portion 512 of the third manifold plate 500 and an ink supply portion 415 (see FIG. 8) of the groove penetration portion 412 of the second manifold plate 400. 7), and five ink supply paths formed by communicating with the ink supply portions 315 (see FIG. 6) of the groove penetration portions 312 of the first manifold plate 300 are formed.
[0055]
In addition, in each of the ink manifold flow paths 2, as shown in FIG. 33, the floating island portion 513 (see FIG. 8) of the groove penetration portion 512 of the third manifold plate 500 and the floating island portion 513 of the groove penetration portion 412 of the second manifold plate 400. While the portion 413 (see FIG. 7) and the floating island portion 313 (see FIG. 6) of the groove penetration portion 312 of the first manifold plate 300 are arranged so as to overlap each other (see FIGS. 31 and 32), the third manifold plate is provided. A connecting piece 514 (see FIG. 8) supporting the floating island portion 513 of the groove penetration portion 512 of FIG. 500 and a connecting piece 414 (see FIG. 7) supporting the floating island portion 413 of the groove penetration portion 412 of the second manifold plate 400. The connecting pieces 314 (see FIG. 6) that support the floating island portions 313 of the groove penetration portions 312 of one manifold plate 300 do not overlap with each other. It is disposed (see FIG. 31, FIG. 32).
[0056]
Therefore, as shown in FIG. 31 and FIG. 32, each of the ink manifold flow paths 2 has four floating island portions 515, 413, and 313 overlapping each other, so that each of the ink manifold flow paths 2 has a closed loop shape. The ink flows around the floating islands 515, 413, and 313. At this time, the connecting pieces 514, 414, 314 supporting the floating island portions 515, 413, 313 are arranged so as not to overlap with each other as shown in FIG. 33, and are half-etched as described above. Therefore, the ink can flow smoothly around the floating islands 515, 413, and 313.
[0057]
As shown in FIG. 27, the ink flowing through the ink manifold channel 2 is supplied to the through hole 612 of the supply plate 600, the ink inlet 713, the groove through portion 715, the ink outlet 714 of the aperture 712 of the aperture plate 700, and the base plate 800. Is introduced into the ink pressure chamber 911 of the cavity plate 900 through the through hole 812. At this time, when the ink passes through the through hole 612 of the supply plate 600, the filter hole 613 (see FIGS. 10 and 11) prevents dust from entering the ink.
[0058]
On the other hand, as shown in FIGS. 27 and 29, the ink pressure chamber 911 of the cavity plate 900 is closed by the piezoelectric sheet 10 by laminating the piezoelectric sheet 10 on the cavity plate 900, as shown in FIGS. The drive electrode 11 of the piezoelectric sheet 10 is arranged on the upper surface. At this time, as shown in FIG. 29, the projection part of the substantially rhombus-shaped drive electrode 11 is inside the ink pressure chamber 19A also having a substantially rhombus shape. On the other hand, the projected portion of the contact land portion 14 formed on the portion of the piezoelectric sheet 10 drawn from the acute angle portion of the drive electrode 11 is outside the ink pressure chamber 911 of the cavity plate 900.
[0059]
When a drive voltage is applied between the drive electrode 11 of the piezoelectric sheet 10 and the internal electrodes 22 and 25 (see FIG. 19) via the FPC board 50, the piezoelectric sheet 10 is placed on the ink pressure chamber 911 side of the cavity plate 900. Is deformed, the ink in the ink pressure chamber 911 of the cavity plate 900 is pushed out to the through hole 811 of the base plate 800. Thereafter, the ink extruded into the through holes 811 of the base plate 800 receives the through holes 811 of the base plate 800, the through holes 711 of the aperture plate 700, the through holes 611 of the supply plate 600, the through holes 511 of the third manifold plate 500, The liquid is discharged from the nozzle 111 of the nozzle plate 100 through the through hole 411 of the second manifold plate 400, the through hole 311 of the first manifold plate 300, and the through hole 211 of the cover plate 200.
[0060]
In addition, all the through holes 612 provided in the upper half or the lower half of the supply plate 600 in the longitudinal direction communicate with one ink manifold flow path 2, and thus the upper half of the cavity plate 900 in the longitudinal direction. Alternatively, since the ink is communicated with all the ink pressure chambers 911 provided in the lower half, the ink supplied to one ink manifold channel 2 is provided in the upper half or the lower half of the nozzle plate 100 in the longitudinal direction. The ink is discharged from any one of the nozzles 111.
[0061]
As described in detail above, in the inkjet head 1 of the present embodiment, as shown in FIG. 15, a plurality of ink pressure chambers 911 are arranged in a matrix in the cavity plate 900 so as to be adjacent to each other. As shown in FIGS. 6 to 8, the first manifold plate 300, the second manifold plate 400, and the third manifold plate 500 each have two groove penetration portions 312, 412, and 512 formed in FIG. 30. 32, two ink manifold flow paths 2 are formed (see FIG. 27), and each of the two ink manifold flow paths 2 has an upper half or a longitudinal direction of the supply plate 600 in the longitudinal direction. All the through holes 612 provided in the lower half communicate with each other, and eventually communicate with all the ink pressure chambers 911 provided in the upper half or the lower half of the cavity plate 900 in the longitudinal direction.
[0062]
Therefore, a large number of discharge channels as shown in FIG. 28 passing through one ink pressure chamber 911 communicate with the ink manifold flow path 2, but as shown in FIGS. 2 is formed in a closed loop, ink is ejected in an ejection channel shown in FIG. 28 through a certain ink pressure chamber 911, and a pressure wave is generated in the ink in the ink manifold flow path 2. Also, this pressure wave only propagates while swirling in the loop-shaped ink manifold flow path 2 and passes through another ink pressure chamber 911 adjacent to the ink pressure chamber 911 in a discharge channel as shown in FIG. There is no breakage of the meniscus and no air enters from there.
[0063]
That is, in the inkjet head 1 of the present embodiment, the first manifold plate 300, the second manifold plate 400, and the third manifold plate 500 are formed by the two groove penetration portions 312, 412, 512 respectively. Since the ink manifold flow path 2 is formed in a closed loop, ink is discharged in a discharge channel as shown in FIG. 28 through a certain ink pressure chamber 911, and a pressure wave is generated in the ink in the ink manifold flow path 2. Is generated, this pressure wave simply propagates by swirling the loop-shaped ink manifold flow path 2 and passes through another ink pressure chamber 911 adjacent to the ink pressure chamber 911 as shown in FIG. Without breaking the meniscus in the discharge channel, air can enter from there In Ino, without being affected by the discharge channel, as shown in the adjacent Figure 28, it can be said that that attempt to maintain stable ink ejection.
[0064]
Further, in the ink jet head 1 of the present embodiment, in the supply plate 600 laminated on the third manifold plate 500, the ink supply to the groove penetrating portion 512 of the third manifold plate 500 constituting a part of the ink manifold channel 2 is performed. Ten ink supply ports 601 communicating with the unit 515 are provided (see FIGS. 2 and 30 to 32), and even if one of the ink supply ports 601 of the supply plate 600 is clogged, the supply plate Since the ink can be supplied to the ink manifold channel 2 from the other ink supply ports 601 of the ink 600, more stable ink discharge can be maintained.
[0065]
In the inkjet head 1 according to the present embodiment, as shown in FIGS. 6 to 8, the first manifold plate 300, the second manifold plate 400, and the third manifold plate 500 are part of the ink manifold flow path 2. Floating island portions 313, 413, 513 surrounded by the groove penetration portions 312, 412, 512, and connecting pieces 314, 414, 514 supporting the floating island portions 313, 423, 513. In this regard, the first manifold plate 300, the second manifold plate 400, and the third manifold plate 500 are half-etched to form the connection pieces 314, 414, and 514 that support the floating island portions 313, 423, and 513. Thus, the ink manifold channel 2 is formed in a closed loop shape (see FIGS. 30 to 33). As shown in FIG. 33, the ink can pass through the ink manifold flow path 2 above or below the half-etched connection pieces 314, 414, and 514, and constitutes a part of the ink manifold flow path 2. Since the ink can freely flow around the floating islands 313, 413, 513 surrounded by the groove penetrations 312, 412, 512, a structure is created in which the pressure wave generated in the ink easily propagates while turning. It can be said that.
[0066]
Note that the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the gist of the present invention.
For example, in the inkjet head 1 according to the present embodiment, the first manifold plate 300, the second manifold plate 400, and the third manifold plate 500 are half-etched to form the connection pieces that support the floating island portions 313, 423, and 513. The ink manifold flow path 2 is formed in a closed loop shape by forming 314, 414, 514 (see FIGS. 30 to 33). The ink manifold flow path to which a number of ejection channels communicate may be formed in a closed loop without providing a connecting piece for supporting the floating island portion.
[0067]
【The invention's effect】
In the ink jet head of the present invention, since the ink manifold flow path of the manifold plate is formed in a closed loop, ink is discharged in a discharge channel passing through a certain ink pressure chamber, and the pressure inside the ink in the ink manifold flow path is reduced. Even if a wave is generated, this pressure wave only propagates by swirling through the loop-shaped ink manifold flow path, breaking the meniscus in the discharge channel passing through another ink pressure chamber adjacent to the ink pressure chamber. Since there is no air and no air enters from there, it can be said that the ink is not affected by the adjacent ejection channel and the stable ink ejection is maintained.
[0068]
Further, in the ink jet head of the present invention, there is provided a supply plate laminated on the manifold plate and provided with an ink supply port communicating with the ink manifold flow path of the manifold plate, and two or more ink supply ports of the supply plate are provided. For example, even if one of the ink supply ports of the supply plate becomes clogged, ink can be supplied from the ink supply port of another supply plate to the ink manifold flow path of the manifold plate, so that a more stable ink can be supplied. Discharge can be maintained.
[0069]
Further, in the inkjet head of the present invention, the manifold plate includes a floating island portion surrounded by the ink manifold flow path of the manifold plate, and a connecting piece that supports the floating island portion of the manifold plate, and half-etches the manifold plate. By forming the connecting piece of the manifold plate by this, if the ink manifold flow path of the manifold plate is formed in a closed loop, the ink manifold flow path of the manifold plate is above or below the connecting piece of the half-etched manifold plate. Thus, it can be said that a structure is created in which the pressure wave generated in the ink easily propagates while turning, since the ink can freely flow around the floating island portion of the manifold plate.
[Brief description of the drawings]
FIG.
FIG. 1 is an exploded perspective view illustrating a schematic configuration of an inkjet head according to an embodiment of the present invention.
FIG. 2 is an exploded perspective view showing a laminated structure of the inkjet head according to one embodiment of the present invention.
FIG. 3 is a plan view showing a group of small-diameter ink jet nozzles provided on a nozzle plate in the inkjet head according to the embodiment of the present invention.
FIG. 4 is a plan view showing a group of through-holes for a small-diameter ink passage provided in a cover plate in the inkjet head according to the embodiment of the present invention.
FIG. 5 is a plan view showing a part of a lower side of a cover plate in the inkjet head according to the embodiment of the present invention.
FIG. 6 is a plan view showing a part of the front side of the first manifold plate in the inkjet head according to the embodiment of the present invention.
FIG. 7 is a plan view showing a part of a front side of a second manifold plate in the inkjet head according to the embodiment of the present invention.
FIG. 8 is a plan view showing a part of the front side of a third manifold plate in the inkjet head according to the embodiment of the present invention.
FIG. 9 illustrates a group of through-holes for a small-diameter ink passage and a through-hole for introducing a micro-diameter ink, and a small-diameter ink supply port provided in a supply plate in the inkjet head according to the embodiment of the present invention. It is the top view shown.
FIG. 10 is an enlarged plan view of a small-diameter ink introduction through hole provided in a supply plate in the inkjet head according to the embodiment of the present invention.
FIG. 11 is an enlarged cross-sectional view of a small-diameter ink introduction through hole provided in a supply plate in the inkjet head according to the embodiment of the present invention.
FIG. 12 shows a group of through-holes for a small-diameter ink passage provided in an aperture plate, a small-diameter ink supply port, and a small-diameter ink supply port in an ink-jet head according to an embodiment of the present invention. FIG.
FIG. 13 is an enlarged plan view of a diaphragm portion for introducing minute ink provided on an aperture plate in the inkjet head according to the embodiment of the present invention.
FIG. 14 shows a group of through-holes for a small-diameter ink passage and through-holes for introducing a micro-diameter ink, and a small-diameter ink supply port provided in a base plate in the ink jet head according to one embodiment of the present invention. FIG.
FIG. 15 is a plan view showing a group of ink pressure chambers provided in a cavity plate and a small-diameter ink supply port in the inkjet head according to one embodiment of the present invention.
FIG. 16 is an enlarged plan view of a small-diameter ink supply port provided on a supply plate in the inkjet head according to the embodiment of the present invention.
FIG. 17 is a plan view showing a piezoelectric sheet in the inkjet head according to one embodiment of the present invention.
FIG. 18 is an enlarged plan view of a driving electrode of a piezoelectric sheet in the inkjet head according to one embodiment of the present invention.
FIG. 19 is an enlarged cross-sectional view of a piezoelectric sheet and a driving electrode in the inkjet head according to one embodiment of the present invention.
FIG. 20 is an enlarged sectional view of one common electrode of a piezoelectric sheet in the ink jet head according to one embodiment of the present invention.
FIG. 21 is an enlarged sectional view of the other common electrode of the piezoelectric sheet in the ink jet head according to one embodiment of the present invention.
FIG. 22 is an enlarged sectional view of a dummy electrode of a piezoelectric sheet in the ink jet head according to one embodiment of the present invention.
FIG. 23 is a plan view of an extended portion of an FPC board in the inkjet head according to one embodiment of the present invention.
FIG. 24 is a partially enlarged view of an extended portion of an FPC board in the inkjet head according to one embodiment of the present invention.
FIG. 25 is a cross-sectional view of a contact land portion of an extended portion of the FPC board in the inkjet head according to one embodiment of the present invention.
FIG. 26 is a cross-sectional view when an FPC board and a piezoelectric sheet are connected in the inkjet head according to one embodiment of the present invention.
FIG. 27 is a cross-sectional view illustrating a flow path of ink ejected from one nozzle of a nozzle plate in the inkjet head according to an embodiment of the present invention.
FIG. 28 is a perspective view showing a part of a flow path of ink ejected from one nozzle of a nozzle plate in the inkjet head according to one embodiment of the present invention.
FIG. 29 is a plan view showing a part of a flow path of ink ejected from one nozzle of a nozzle plate in the inkjet head according to one embodiment of the present invention.
FIG. 30 is a plan view showing an ink manifold channel from the front side of a third manifold plate in the ink jet head according to one embodiment of the present invention.
FIG. 31 is a plan view showing the ink manifold flow paths from the front side of the third manifold plate in the ink jet head according to one embodiment of the present invention, and shows only the ink manifold flow paths formed in the upper half in the longitudinal direction. It is shown.
FIG. 32 is a plan view showing the ink manifold flow path from the front side of the third manifold plate in the ink jet head according to one embodiment of the present invention, and shows only the ink manifold flow path formed in the lower half in the longitudinal direction. It is shown.
FIG. 33 is a perspective view showing a part of an ink manifold channel in the inkjet head according to an embodiment of the present invention.
FIG. 34 is a plan view of a flow path forming plate of a conventional inkjet head.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ink jet head 2 Ink manifold channel 300 First manifold plate 312 Groove penetration part 313 of first manifold plate Floating island part 314 of first manifold plate Connection piece 400 supporting floating island part of first manifold plate 400 Second manifold plate 412 Groove penetration portion 413 of second manifold plate Floating island portion 414 of second manifold plate Connection piece 500 supporting floating island portion of second manifold plate 500 Third manifold plate 512 Groove penetration portion 513 of third manifold plate 513 Floating island portion of third manifold plate 514 Connection piece 600 supporting floating island part of third manifold plate Supply plate 601 Ink supply port 900 of supply plate Cavity plate 911 Ink pressure chamber of cavity plate

Claims (3)

A cavity plate in which a plurality of ink pressure chambers are arranged adjacent to each other in a matrix,
A manifold plate formed with an ink manifold flow path communicating with a group of ink pressure chambers of the cavity plate,
An ink jet head, wherein an ink manifold channel of the manifold plate is formed in a closed loop shape. The inkjet head according to claim 1,
A supply plate laminated to the manifold plate and provided with an ink supply port communicating with an ink manifold flow path of the manifold plate;
An ink jet head, wherein two or more ink supply ports of the supply plate are provided. An inkjet head according to claim 1 or claim 2,
The manifold plate includes:
A floating island portion surrounded by an ink manifold channel of the manifold plate,
A connection piece that supports a floating island portion of the manifold plate,
An ink jet head, wherein a connecting piece of the manifold plate is formed by half-etching the manifold plate.

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