JP3714151B2 - Inkjet printer head - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of inkjet printer heads.
[0002]
[Prior art]
A conventional inkjet printer head is formed for each of a plurality of nozzles and a cavity plate corresponding to each of the nozzles and having a plurality of pressure chambers for supplying ink from an ink supply source to the nozzles. Plate-type actuators that are stacked with a piezoelectric sheet sandwiched between common drive electrodes and a common electrode that is adjacent to the pressure chamber. This actuator is used as a cavity plate, and each drive electrode in the actuator corresponds to each pressure chamber. It was the structure laminated | stacked so that.
[0003]
In such a configuration, by applying a voltage between an arbitrary drive electrode among the drive electrodes in the actuator and the common electrode, the portion of the drive electrode to which the voltage is applied in the piezoelectric sheet is applied in the stacking direction of the piezoelectric. Distortion occurs, and the internal volume of the pressure chamber corresponding to each drive electrode is reduced by the pressure due to this distortion, so that the ink in the ink pressure chamber of this pressure chamber is ejected in droplet form from the nozzle, Predetermined printing is performed.
[0004]
By the way, after applying a voltage between the drive electrode and the common electrode, it is necessary to quickly attenuate the pressure applied to the pressure chamber. In order to attenuate this pressure, ink flows in the pressure chamber. Generally, the resistance of the flow path (hereinafter referred to as “flow path resistance”) is increased. For example, a method is known in which the channel resistance is increased by reducing the cross-sectional area of the flow channel on the inflow side of the pressure chamber or by narrowing the width of the pressure chamber.
[0005]
[Problems to be solved by the invention]
However, in the method of reducing the cross-sectional area of the flow path on the inflow side of the pressure chamber, a portion having a smaller cross-sectional area is originally provided for the flow path having a smaller cross-sectional area. The variation in the characteristics of the On the other hand, the method of reducing the width of the pressure chamber has a certain limit because the width of the drive electrode must be taken into consideration. In other words, the width of the pressure chamber has to be made larger than the width of the drive electrode in consideration of a margin of misalignment, so there is a limit to reducing the channel width.
[0006]
It is an object of the present invention to provide an ink jet printer head that can solve the above-described problems and can efficiently increase the flow path resistance.
[0007]
[Means for Solving the Problems]
In order to solve the above problem, an ink jet printer head according to claim 1 includes a nozzle plate having a plurality of nozzles , a base plate having a plurality of pressure chambers corresponding to each of the nozzles, and the base plate and the nozzle plate. A manifold plate having a common ink chamber for supplying ink to the plurality of pressure chambers, and both ends of the pressure chambers positioned between the manifold plate and the base plate. A plurality of pressure generators that apply pressure to the pressure chambers corresponding to each of the pressure chambers and cavity plates in which spacer plates having through-holes and ink supply holes connected to the nozzles are stacked. An actuator having a portion, and the pressure chamber and the pressure As the generator corresponding to a said inkjet printer head cavity plate and formed by stacking said actuator, said pressure chamber, on both sides of said spacer plate side to the pressure generating portion side of the base plate open formed, the area of the surface of the corresponding side and the spacer plate in a cross section perpendicular to the flow direction of the ink in the pressure chamber, be less than the area of the surface of the corresponding side and the pressure generating portion Rutotomoni Both portions are provided substantially in the ink flow direction.
[0008]
According to the ink jet printer head of claim 1, the pressure chambers are formed by opening on both surfaces of the base plate on the pressure generating portion side and the spacer plate side, and the cross section is orthogonal to the ink flow direction in the pressure chamber. The area of the surface corresponding to the spacer plate is made smaller than the area of the surface corresponding to the pressure generating portion, and both portions are provided substantially in the ink flow direction. The flow path resistance can be efficiently obtained, and the dimension of the pressure generating portion can be taken into consideration only on one side, and therefore the flow path resistance can be obtained efficiently in the vicinity of the other side.
[0009]
The ink jet printer head according to claim 2, wherein, in order to solve the problem, in the ink jet printer head according to claim 1, the actuator stacks piezoelectric sheets having a size extending over the plurality of pressure chambers, and the piezoelectric printer head. A drive electrode corresponding to each pressure chamber is provided between the sheets .
[0010]
[0011]
The ink jet printer head according to claim 3, wherein, in order to solve the problem, the ink jet printer head according to claim 1 or 2, wherein the ink chamber has an ink flow direction at one end of the pressure chamber on the ink supply hole side. A throttle part having a smaller cross-sectional area than that of the pressure chamber is connected.
[0012]
According to the ink jet printer head of the third aspect, at one end of the pressure chamber on the ink supply source side, there is a throttle portion for controlling the flow path resistance. Therefore, the flow path resistance can be efficiently obtained while suppressing variations in the characteristics of the printer head as much as possible.
[0013]
Inkjet printer head according to claim 4, wherein, in order to solve the above problems, in the ink jet printer head according to any one of claims 1 to 3, wherein the base plate is to be formed using a 42 alloy Features.
[0014]
According to the ink jet printer head according to claim 4, wherein, by using a base plate 42 alloy, it is possible to easily form the pressure chamber by etching.
[0015]
Inkjet printer head according to claim 5, wherein, in order to solve the above problems, in the ink jet printer head according to any one of claims 1 to 3, wherein the base plate, characterized by being formed using the resin And
[0016]
According to the ink jet printer head according to claim 5, wherein, by using a resin-based plates can be formed press or, easy pressure chamber molding.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings. The following description is an embodiment when the present invention is applied to a piezoelectric ink jet head.
[0018]
1, 2 and 3 are perspective views of a piezoelectric inkjet printer head according to an embodiment of the present invention. FIG. 4 is a bottom view of the main body frame 1.
[0019]
As shown in FIG. 3, a main body frame 1 mounted on a known carriage (not shown) that runs along a recording medium is formed in a substantially box shape with an open top surface, and four ink cartridges from above. An ink supply passage 4a that can be connected to an ink discharge portion (not shown) of each ink cartridge is provided in one side portion 3a of the mounting portion 3; 4 b, 4 c, 4 d communicate with the lower surface of the bottom plate 5 of the main body frame 1. A rubber packing (not shown) is arranged on the upper surface of the one side portion 3a of the mounting portion 3 so as to be in close contact with the ink discharge portion (not shown) of each ink cartridge.
[0020]
The bottom plate 5 is formed in a horizontal shape so as to protrude downward from the mounting portion 3, and as shown in FIGS. 2 and 4, two front head units 6 to be described later are provided on the lower surface side of the bottom plate 5. Two support portions 8 for arranging in parallel are formed in a stepped shape. Each support portion 8 is formed with a plurality of cavities 9 a and 9 b for fixing with a UV adhesive so as to penetrate vertically.
[0021]
FIG. 5 is a perspective view of the front head unit 6. FIG. 6 is a sectional view of the front head unit. As shown in FIGS. 5 and 6, the front head unit 6 includes a plurality of stacked cavity plates 10 and a plate-type bonded and stacked on the cavity plates 10 with an adhesive or an adhesive sheet. In order to electrically connect the piezoelectric actuator 20 and an external device on the upper surface thereof, a flexible flat cable 40 is formed by overlapping and bonding with an adhesive, and is opened on the lower surface side of the lowermost cavity plate 10. Ink is ejected downward from the nozzle 15.
[0022]
FIG. 7 is an exploded perspective view of the cavity plate 10. FIG. 8 is an exploded perspective view of the cavity plate 10. As shown in FIG. 8, the cavity plate 10 has a structure in which five thin metal plates of a nozzle plate 11, two manifold plates 12, a spacer plate 13 and a base plate 14 are laminated and bonded together with an adhesive. is there. In the present embodiment, each of these plates 11 to 14 is made of 42% nickel alloy steel plate (42 alloy) and has a thickness of about 50 μm to 150 μm. Each of these plates 11 to 14 is not limited to metal, and may be formed of resin, for example.
[0023]
In the nozzle plate 11, a plurality of ink ejection nozzles 15 having a minute diameter (in this embodiment, about 25 μm) are spaced at a minute pitch P along the center lines 11 a and 11 b in the longitudinal direction of the nozzle plate 11. It is drilled in a staggered arrangement. In the two manifold plates 12, common ink chambers 12 a and 12 b are formed so as to extend along both sides of the row of nozzles 15. The common ink chambers 12 a and 12 b are sealed by stacking the nozzle plate 11 and the spacer plate 13 on the two manifold plates 12.
[0024]
Further, as shown in FIG. 8, a plurality of narrow pressure chambers 16 extending in a direction orthogonal to the longitudinal center lines 14a and 14b are formed in the base plate 14 in a staggered arrangement. The base plate 14 is provided with a throttle portion 16 d connected to each pressure chamber 16. Further, an ink supply hole 16b connected to the throttle portion 16d is formed. Each ink supply hole 16 b communicates with the common ink chamber 12 a in the manifold plate 12 through ink supply holes 18 drilled in the left and right sides of the spacer plate 13. Here, the cross-sectional area perpendicular to the direction in which the ink flows in each throttle portion 16 d is smaller than the cross-sectional area in each pressure chamber 16. This is because the flow path resistance is increased by reducing the cross-sectional area of the throttle portion 16d. The cross-sectional shape of each pressure chamber 16 will be described later.
[0025]
One end portion 16a of each pressure chamber 16 has a through hole 17 having a small diameter formed in the staggered arrangement of nozzles 15 in the nozzle plate 14 in the spacer plate 13 and the two manifold plates 12 in the same staggered arrangement. Communicated through.
[0026]
As a result, the ink that has flowed into the common ink chambers 12a and 12b from the ink supply holes 19a and 19b drilled at one end of the base plate 14 and the spacer plate 13 is transferred from the common ink chamber 12a to the respective ink supply holes 18 and the ink supply. The gas is distributed to each pressure chamber 16 through the hole 16b and the throttle portion 16d. Then, ink flows in the direction of the one end portion 16 a of each pressure chamber 16, passes through each through hole 17, and reaches the nozzle 15 corresponding to each pressure chamber 16.
[0027]
FIG. 9 is an exploded enlarged perspective view of the piezoelectric actuator 20. As shown in FIG. 9, the piezoelectric actuator 20 has a structure in which two piezoelectric sheets 21 and 22 and one insulating sheet 23 are laminated. On the upper surface of the lowermost piezoelectric sheet 21, a plurality of narrow drive electrodes 24 corresponding to the respective pressure chambers 16 in the cavity plate 10 are provided in a staggered arrangement. Further, one end 24 a of each drive electrode 24 is formed so as to be exposed on the left and right side surfaces 20 c orthogonal to the front and back surfaces 20 a and 20 b of the piezoelectric actuator 20.
[0028]
A common electrode 25 common to the plurality of pressure chambers 16 is provided on the upper surface of the piezoelectric sheet 22 at the next stage. Similarly to the one end portion 24a of each drive electrode 24, the one end portion 25a of the common electrode 25 is also formed so as to be exposed on the left and right side surfaces 20c.
[0029]
On the upper surface of the uppermost insulating sheet 23, a surface electrode 26 for each of the drive electrodes 24 and a surface electrode 27 for the common electrode 25 are provided so as to be aligned along the left and right side surfaces 20c.
[0030]
The left and right side surfaces 20c are provided with a first recessed groove 30 at one end 24a of each drive electrode 24 and a second recessed groove 31 at one end 25a of the common electrode 25 so as to extend in the stacking direction. ing. In each first recessed groove 30, as shown in FIG. 6, a side electrode 32 that electrically connects each drive electrode 24 and each surface electrode 26 is provided in the second recessed groove 31. Side electrodes 33 that electrically connect the electrode 25 and the surface electrode 27 are respectively formed. The electrodes 28 and 29 are discarded patterns.
[0031]
Each region of the piezoelectric sheet 22 sandwiched between the position corresponding to each drive electrode 24 and the common electrode 25 becomes a pressure generating portion corresponding to each pressure chamber 16.
[0032]
The cavity plate 10 and the piezoelectric actuator 20 configured as described above are stacked such that each pressure chamber 16 in the cavity plate 10 and the drive electrode 24 in the piezoelectric actuator 20 correspond to each other. Further, when the flexible flat cable 40 is pressed against the upper surface 20 a of the piezoelectric actuator 20, various wiring patterns (not shown) in the flexible flat cable 40 are electrically connected to the surface electrodes 26 and 27. Are joined together.
[0033]
In such a configuration, by applying a voltage between an arbitrary drive electrode 24 of each drive electrode 24 in the piezoelectric actuator 20 and the common electrode 25, the drive electrode 24 to which a voltage is applied in the piezoelectric sheet 22 is applied. A distortion in the stacking direction due to the piezoelectric effect is generated in the portion, that is, the pressure generating portion. Then, the internal volume of the pressure chamber 16 corresponding to each drive electrode 24 is reduced by the pressure due to this distortion, so that the ink in the pressure chamber 16 is ejected from the nozzle 15 in the form of droplets, and is predetermined. Is printed.
[0034]
Next, the cross-sectional shape of the pressure chamber 16 which is a characteristic part of the present invention will be described in detail. FIG. 10 is a cross-sectional view orthogonal to the ink flow direction in the laminated portion of the cavity plate 10 and the piezoelectric actuator 20. The width 16e above the pressure chamber 16 is larger than the width 50a of the pressure generator 50 of the piezoelectric actuator 20, as shown in FIG. This is because the margin of assembly displacement is taken into consideration and the upper part of the pressure chamber 16 is efficiently received from the pressure generating unit 50. On the other hand, since the pressure chamber 16 does not receive pressure directly from the pressure generation unit 50, it is not necessary to consider the width 50 a of the pressure generation unit 50 of the pressure chamber 16. Accordingly, the lower width 16f of the pressure chamber 16 is smaller than the width 50a of the pressure generating portion 50 of the pressure chamber 16, as shown in FIG.
[0035]
That is, the area of the lower surface of the pressure chamber 16 is smaller than the area of the upper surface corresponding to the pressure generator 50 of the pressure chamber 16. Thereby, in the cross section orthogonal to the ink flow direction in the pressure chamber 16, the flow path resistance below the pressure chamber 16 can be made larger than the upper flow path resistance.
[0036]
In contrast, conventionally, the pressure chamber is formed by etching the base plate 14 from one side, and as shown in FIG. 11, the upper and lower widths of the pressure chamber have substantially the same cross-sectional shape. Therefore, conventionally, in order to narrow the width above and below the pressure chamber, the width of the pressure generating portion must be taken into account, and there is a certain limit, and the flow path resistance cannot be efficiently obtained. It was.
[0037]
On the other hand, in the embodiment according to the present invention, the cross section perpendicular to the ink flow direction in the pressure chamber 16 is provided with a portion having a large flow path resistance and a small portion, and both portions are provided over the ink flow direction. Therefore, the flow path resistance can be efficiently obtained, and even when the pressure generating unit 50 vibrates at a high frequency, the pressure is efficiently attenuated, and the ink meniscus at the nozzle 15 can be stabilized and stabilized. Ink discharge can be performed. Such a pressure chamber 16 can be formed by performing etching with different dimension widths from both surfaces of the base plate 14. When the base plate 14 is formed using a resin, the pressure chamber 16 having such a cross-sectional shape can be formed by pressing, molding, or the like.
[0038]
The cross-sectional shape of the pressure chamber 16 is not limited to those shown in the example of FIG. 1 0, for example, such as a trapezoidal shape, and various improvements and modifications are possible within the scope not departing from the gist of the present invention It is. In addition, when a plurality of base plates 14 are formed and the plates are stacked by forming openings having different cross-sectional areas, it is possible to connect the plurality of openings to form one pressure chamber 16.
[0039]
In the above-described embodiment, the piezoelectric type is used for the pressure generating part in the piezoelectric actuator 20, but the present invention is not limited to this, and an electrostatic pressure generating part or the like may be used. .
[0040]
【The invention's effect】
As described above, according to the ink jet printer head of the first aspect, the pressure chambers are formed to be open on both sides of the pressure generating portion side and the spacer plate side of the base plate, and the ink flow direction in the pressure chamber Since the area of the surface corresponding to the spacer plate in the cross section orthogonal to the area is smaller than the area of the surface corresponding to the pressure generating portion, both portions are provided substantially in the ink flow direction. It is possible to efficiently increase the flow resistance in the entire flow path in the chamber. As a result, the pressure can be efficiently attenuated, stable ink ejection can be performed, and the displacement and size of the pressure generating section can be afforded. The flow path resistance can be efficiently obtained near the other surface.
[0041]
[0042]
According to the ink jet printer head of the third aspect, the one end on the ink supply source side of the pressure chamber has the throttle portion for controlling the flow path resistance. Therefore, the flow path resistance can be efficiently obtained while suppressing variations in the characteristics of the printer head as much as possible.
[0043]
According to the ink jet printer head according to claim 4, wherein, by using a base plate 42 alloy, it is possible to easily form the pressure chamber by etching.
[0044]
According to the ink jet printer head according to claim 5, wherein, by using a resin-based plates can be formed press or, easy pressure chamber molding.
[Brief description of the drawings]
FIG. 1 is a perspective view with a nozzle side of a piezoelectric inkjet head facing up.
FIG. 2 is an exploded perspective view of components of a piezoelectric inkjet head.
FIG. 3 is an exploded perspective view of components when a piezoelectric inkjet head is viewed from above.
FIG. 4 is a bottom view of the bottom plate of the main body frame as viewed from the bottom surface side.
FIG. 5 is a perspective view of a front head unit.
FIG. 6 is a cross-sectional view of the front head unit.
FIG. 7 is an exploded perspective view of a cavity plate.
FIG. 8 is an exploded perspective view of the cavity plate.
FIG. 9 is an exploded perspective view of the piezoelectric actuator.
FIG. 10 is a cross-sectional view orthogonal to the ink flow direction in the laminated portion of the cavity plate and the piezoelectric actuator in the present embodiment.
FIG. 11 is a cross-sectional view orthogonal to the direction of ink flow in a conventional layered portion of a cavity plate and a piezoelectric actuator.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Main body frame 4a, 4b, 4c, 4d Ink supply path 5 Bottom plate 6 Front head unit 10 Cavity plate 11 Nozzle plate 12 Manifold plate 12a, 12b Common ink chamber 13 Spacer plate 14 Base plate 15 Nozzle 16 Pressure chamber 16d Restriction part 18, 19b 19a Ink supply hole 20 Piezoelectric actuator 21, 22 Piezoelectric sheet 23 Insulating sheet 24 Drive electrode 25 Common electrode 26, 27 Surface electrode 30, 31 Recessed groove 32, 33 Side electrode 40 Flexible flat cable

Claims (5)

A nozzle plate having a plurality of nozzles , a base plate having a plurality of pressure chambers corresponding to each of the nozzles, and a common ink located between the base plate and the nozzle plate for supplying ink to the plurality of pressure chambers A manifold plate having a chamber, an ink supply hole located between the manifold plate and the base plate and connecting both ends of each pressure chamber to the common ink chamber and the nozzle, and a spacer plate having a through hole, respectively. A laminated cavity plate, and an actuator including a plurality of pressure generating units that apply pressure to the pressure chambers to discharge the ink corresponding to each of the pressure chambers. The cavity plate and the actuator so as to correspond to each other. An inkjet printer head formed by laminating a preparative,
The pressure chamber is formed by opening on both surfaces of the base plate on the pressure generating portion side and the spacer plate side, and the surface on the side corresponding to the spacer plate in a cross section perpendicular to the ink flow direction in the pressure chamber . area, and the pressure generating unit and the corresponding side surface of the smaller than the area to Rutotomoni, inkjet printer head, characterized in that provided over the flow direction of the substantially ink that both parts of. 2. The actuator according to claim 1, wherein the actuator has a structure in which piezoelectric sheets having a size extending over the plurality of pressure chambers are stacked, and drive electrodes corresponding to the pressure chambers are provided between the piezoelectric sheets . Inkjet printer head. 3. The narrowed portion having a smaller cross-sectional area perpendicular to the ink flow direction than that of the pressure chamber is connected to one end of the pressure chamber on the ink supply hole side. Inkjet printer head. The base plate, the ink jet printer head according to any one of claims 1 to 3, characterized in that it is formed using a 42 alloy. The base plate, the ink jet printer head according to any one of claims 1 to 3, characterized in that it is formed using a resin.

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