JP2002137386A - Ink jet printer head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet printer head in which ink ejection performance of respective pressure chambers can be made uniform. SOLUTION: The ink jet printer head comprises an actuator comprising a common ink chamber for distributing ink from an ink supply source through ink supply holes to a plurality of pressure chambers, and a plurality of pressure generating sections corresponding, respectively, to the pressure chambers and applying a pressure for ejecting ink thereto. The common ink chamber is located in a plane parallel with a plane defined by the plurality of pressure chambers and extends in the array direction thereof while overlapping the plurality of pressure chambers at least partially in the direction orthogonal to that plane. Furthermore, the common ink chamber has a cross-sectional area decreasing at a constant rate in the direction recording from the ink supply source at least an end part remote from the ink supply source. In such an ink jet printer head, a space chamber for substantially correcting variation of rigidity at a position corresponding to each pressure chamber of a member forming the common ink chamber is provided contiguously to the part where the cross-sectional area of the common ink chamber decreases.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention belongs to the technical field of ink jet printer heads.

[0002]

2. Description of the Related Art A conventional ink jet printer head includes a plurality of nozzles, a plurality of pressure chambers for supplying ink to the nozzles corresponding to the respective nozzles,
A common ink chamber for distributing ink from an ink supply source to a plurality of pressure chambers via an ink supply hole, and a plurality of pressure generating units for applying pressure for ejecting ink to the pressure chambers corresponding to each of the pressure chambers. , Was provided.

In such a configuration, the common ink chamber is located in a plane parallel to a plane formed by the plurality of pressure chambers, and at least partially overlaps the plurality of pressure chambers in a direction orthogonal to the plane. The plurality of pressure chambers have a shape elongated in the row direction, and the cross-sectional area in the row direction is substantially the same from the vicinity of the ink supply source of the common ink chamber to the distance from the ink supply source.

However, in the common ink chamber having such a shape, air bubbles are apt to accumulate in the interior of the common ink chamber (a part far from the ink supply source), which causes an ink ejection failure or prevents the ink from being filled by the air bubbles. There was a problem.

Therefore, for example, Japanese Patent Application Laid-Open No. 2000-4325
In the ink jet recording head disclosed in Japanese Patent Application Publication No. 3 (1999) -1995, the shape of the common ink chamber is reduced at a constant rate in a direction away from the ink supply source so that the depth of the common ink chamber is reduced. It has been improved to make it easier to discharge residual air bubbles that easily accumulate in the air.

[0006]

However, if the cross-sectional area of the common ink chamber is reduced at a constant rate in a direction away from the ink supply source as described above, the common ink chamber will Therefore, there is a difference in the rigidity between the respective members forming the pressure chamber and the respective positions corresponding to the respective pressure chambers. For example, as shown in FIG. 11, the rigidity of the member at the portion (A portion) where the cross-sectional area of the common ink chamber is large,
A difference occurs between the rigidity of the member in the portion (section B) where the cross-sectional area of the common ink chamber is small.

As a result, the pressure to be applied from the pressure generating section to the ink in each pressure chamber is partially absorbed by the deformation of the member in a portion having a small rigidity, and corresponds to a portion having a large sectional area (portion A). The pressure chamber and the portion with a small cross-sectional area (B
There is a problem that a difference occurs in the ink ejection performance between the pressure chambers corresponding to the section (1) and (2).

An object of the present invention is to provide an ink jet printer head which can solve the above-mentioned problems and can make the ink discharge performance in each pressure chamber uniform.

[0009]

According to a first aspect of the present invention, there is provided an ink jet printer head comprising:
A plurality of nozzles, a plurality of pressure chambers for supplying ink to the nozzles corresponding to each of the nozzles, and the ink from an ink supply source is distributed to the plurality of pressure chambers via ink supply holes. A common ink chamber, and an actuator including a plurality of pressure generating units that respectively apply pressures for discharging the ink to the pressure chambers corresponding to the pressure chambers, wherein the common ink chamber includes the plurality of pressures. The plurality of pressure chambers are located in a plane parallel to a plane formed by the chambers, and at least partially overlap with the plurality of pressure chambers in a direction perpendicular to the plane, extend in a row direction formed by the plurality of pressure chambers, and further extend in the row direction. The ink-jet printer head has a shape whose cross-sectional area gradually decreases in a direction away from the ink supply source, at least at an end portion away from the ink supply source. In the above, a space chamber is provided adjacent to a portion where the cross-sectional area of the common ink chamber is reduced, for substantially correcting a change in rigidity of a member forming the common ink chamber at a position corresponding to each of the pressure chambers. It is characterized by.

According to the ink jet printer head of the first aspect, the rigidity at the position corresponding to each pressure chamber of the member forming the common ink chamber is adjacent to the portion where the cross-sectional area of the common ink chamber is reduced. Since the space chamber for substantially correcting the change is provided, the pressure applied to the ink in each of the pressure chambers from the pressure generating section is substantially equal in all the pressure chambers, so that the ink ejection performance can be made uniform.

According to a second aspect of the present invention, there is provided an ink jet printer head according to the first aspect, wherein the first plate member forming the plurality of pressure chambers and the common ink are provided. And a second plate member forming a chamber.
Wherein the space chamber is formed in the same plane as the common ink chamber.

According to the ink jet printer head of the present invention, since the space chamber is provided in the same plane as the common ink chamber in the second plate member forming the common ink chamber, each space is provided from the pressure generating section. Since the stress applied via the pressure chambers becomes substantially uniform at the position corresponding to each pressure chamber of the member forming the common ink chamber in the second plate member, the ink ejection performance in each pressure chamber is made uniform. Can be planned.

According to a third aspect of the present invention, there is provided an ink jet printer head according to the first or second aspect.
Wherein the sum of the cross-sectional area of the common ink chamber and the cross-sectional area of the space chamber is substantially equal in a cross section at an arbitrary position in a direction orthogonal to a column direction formed by the plurality of pressure chambers. It is characterized by.

According to the third aspect of the present invention, in a cross section at an arbitrary position in a direction orthogonal to the column direction formed by the plurality of pressure chambers, the sum of the cross sectional area of the common ink chamber and the cross sectional area of the space chamber is provided. Are substantially equal, the stiffness of the members forming the common ink chamber at the positions corresponding to the respective pressure chambers can be made substantially equal, so that the ink discharge performance in each pressure chamber can be made uniform.

[0015]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. The following description is an embodiment in which the present invention is applied to a piezoelectric inkjet head.

FIGS. 1, 2 and 3 are perspective views of a piezoelectric ink jet printer head according to an embodiment of the present invention. FIG. 4 is a bottom view of the main body frame 1.

As shown in FIG. 3, a main body frame 1 mounted on a known carriage (not shown) running along a recording medium is formed in a substantially box shape having an open top surface. One ink supply source, for example, a mounting portion 3 to which an ink cartridge (not shown) can be removably mounted, and one side portion 3a of the mounting portion 3 has an ink discharging portion (not shown) of each ink cartridge. 3), the ink supply passages 4a, 4b, 4c, and 4d communicate with the lower surface of the bottom plate 5 of the main body frame 1. A packing (not shown) made of rubber or the like is provided on the upper surface of the one side portion 3a of the mounting portion 3 so as to be in close contact with an ink discharge portion (not shown) of each ink cartridge.

The bottom plate 5 is formed horizontally so as to protrude downward from the mounting portion 3 by one step. As shown in FIGS. 2 and 4, a lower surface of the bottom plate 5 has a front head unit 6 to be described later. Are formed in a stepped shape for arranging two in parallel. A plurality of cavities 9a and 9b for fixing with a UV adhesive are formed in each support portion 8 so as to penetrate vertically.

FIG. 5 is a perspective view of the front head unit 6. As shown in FIG. FIG. 6 is a sectional view of the front head unit. Front head unit 6
As shown in FIGS. 5 and 6, a plurality of laminated cavity plates 10 and a plate-shaped piezoelectric actuator 20 bonded and laminated to the cavity plates 10 via an adhesive or an adhesive sheet are provided. A flexible flat cable 40 is formed on the upper surface of the lower surface of the cavity plate 10 by an adhesive so as to be electrically connected to an external device. Ink is ejected.

FIG. 7 is an exploded perspective view of the cavity plate 10. As shown in FIG. FIG. 8 shows the cavity plate 1
FIG. 2 is an exploded enlarged perspective view of FIG. The cavity plate 10, as shown in FIG.
Two manifold plates 12, spacer plate 1
3. A structure in which five thin metal plates of the base plate 14 are overlapped and bonded with an adhesive, respectively. In the present embodiment, each of these plates 11 to 14 is made of a 42% nickel alloy steel plate (42 alloy) and has a thickness of 50 μm to 150 μm.
About the same thickness. Each of these plates 1
1 to 14 are not limited to metal and may be formed of, for example, resin.

As shown in FIG. 8, a plurality of narrow pressure chambers 16 extending in a direction perpendicular 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 16 d connected to each pressure chamber 16. Further, the ink supply hole 16 connected to the throttle portion 16d
b is drilled. Each ink supply hole 16b communicates with a common ink chamber 12a in the manifold plate 12 through each ink supply hole 18 formed in both right and left portions of the spacer plate 13. Here, the cross-sectional area orthogonal to the direction in which the ink flows in each of the constricted portions 16 d is smaller than the cross-sectional area of each of the pressure chambers 16. This is because the flow path resistance is increased by reducing the cross-sectional area of the throttle portion 16d.

One end 16a of each pressure chamber 16 is connected to a staggered array of nozzles 15 in the nozzle plate 11 by a spacer plate 13 and two manifold plates 12a.
Small diameter through-holes 1 also drilled in a staggered arrangement
7.

The base plate 14 and the spacer plate 13 are provided with ink supply holes 19b and 19a for supplying ink from the ink cartridge to the common ink chamber 12a of the manifold plate 12, respectively.

In the two manifold plates 12, common ink chambers 12a and 12b are located in a plane parallel to a plane formed by the plurality of pressure chambers 16 in the base plate 14,
Further, at least a part of the plurality of pressure chambers 16 overlaps in a direction perpendicular to the surface, and is formed so as to extend in the row direction formed by the plurality of pressure chambers 16. In addition, the common ink chambers 12a and 12b are provided at the ends (portion C in FIG. 7) remote from the ink supply holes 19a and 19b.
In a direction away from 9a, 19b, the cross-sectional area is reduced at a constant rate. This is for the purpose of facilitating the discharge of residual air bubbles that are likely to accumulate at the ends of the common ink chambers 12a and 12b, as described above.

Further, the two manifold plates 12
In FIG. 7, the common ink chambers 12a and 12b are connected to the common ink chambers 12a and 12b at the end where the cross-sectional area of the common ink chambers 12a and 12b decreases (section C in FIG.
A space 50 is formed adjacent to 2b. This space chamber 50 is a characteristic part of the present invention, and the common ink chamber 1
2a and 12b (manifold plate 1)
This is to substantially correct the change in rigidity at the position corresponding to each pressure chamber 16 in 2).

FIG. 9 is an enlarged view of an end portion (portion C in FIG. 7) of the manifold plate 12 shown in FIG. In the example of FIG. 9, a cross section at an arbitrary position at an end portion (C part in FIG. 7) of the manifold plate 12 (a cross section at an arbitrary position in a direction orthogonal to the row direction formed by the plurality of pressure chambers 16 in the base plate 14). 2), the sum of the cross-sectional areas of the common ink chambers 12a and 12b and the cross-sectional area of the space chamber 50 is made substantially equal. Thereby, the common ink chamber 12
The rigidity of the manifold plate 12 at the portion where the cross-sectional area of the ink chambers a and 12b is large can be made substantially equal to the rigidity of the manifold plate 12 at the portion where the cross-sectional area of the ink chamber is small.

The common ink chambers 12a and 12b have a structure that is sealed by laminating the nozzle plate 11 and the spacer plate 13 with respect to the two manifold plates 12.

In the nozzle plate 11, a plurality of nozzles 15 for discharging ink having a very small diameter (about 25 μm in the present embodiment) are arranged at a fine pitch along the longitudinal center lines 11a and 11b of the nozzle plate 11. The holes are formed in a staggered arrangement at intervals of P.

With the above configuration of the cavity plate 10, the ink flowing into the common ink chambers 12a and 12b from the ink supply holes 19a and 19b formed at one end of the base plate 14 and the spacer plate 13 is supplied to the common ink chamber 12a. Is distributed to each pressure chamber 16 through each ink supply hole 18, each ink supply hole 16b, and the throttle portion 16d. Then, the ink flows in the direction of one end 16 a of each pressure chamber 16, passes through each through hole 17, and reaches the nozzle 15 corresponding to each pressure chamber 16.

Next, FIG.
FIG. 3 is an exploded perspective view of FIG. As shown in FIG. 10, the piezoelectric actuator 20 includes two piezoelectric sheets 2.
1, 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 each pressure chamber 16 in the cavity plate 10 are provided in a staggered arrangement.
One end 24a of each drive electrode 24 is formed so as to be exposed on left and right side surfaces 20c orthogonal to the front and back surfaces 20a and 20b of the piezoelectric actuator 20.

A common electrode 25 common to the plurality of pressure chambers 16 is provided on the upper surface of the next-stage piezoelectric sheet 22. Like the one end 24a of each drive electrode 24, one end 25a of the common electrode 25 is also formed so as to be exposed on the left and right side surfaces 20c. Each drive electrode 24 and common electrode 2
Each region of the piezoelectric sheet 22 sandwiched between the pressure chambers 5 is a pressure generating unit corresponding to each pressure chamber 16.

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 arranged along the left and right side surfaces 20c.

The drive electrodes 2 are provided on the left and right side surfaces 20c.
4 is provided with a first recessed groove 30 at one end 24a of the common electrode 2.
The second recessed groove 31 is provided at one end 25a of the fifth member 5 so as to extend in the laminating direction. Each first concave groove 3
6, a side electrode 32 for electrically connecting each drive electrode 24 and each surface electrode 26 is provided, and a common electrode 25 and a surface electrode 27 are provided in the second concave groove 31, as shown in FIG. And side electrodes 33 for electrically connecting the electrodes to each other. The electrodes 28 and 29 are discarded pattern electrodes.

The cavity plate 1 having the above configuration
0 and the piezoelectric actuator 20, each pressure chamber 16 in the cavity plate 10 and the piezoelectric actuator 20
Are laminated so as to correspond to the drive electrodes 24 in the above.
Also, the upper surface 20 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 by overlapping and pressing the flexible flat cable 40 on a.

In such a configuration, by applying a voltage between any of the drive electrodes 24 of the piezoelectric actuator 20 and the common electrode 25, the drive of the piezoelectric sheet 22 to which the voltage is applied is performed. Electrode 2
In the portion 4, that is, in the pressure generating portion, distortion in the stacking direction due to piezoelectricity occurs. Then, the internal pressure of the pressure chamber 16 corresponding to each drive electrode 24 is reduced by the pressure due to the distortion, so that the ink in the pressure chamber 16 is
5, predetermined printing is performed.

As described above, according to the piezoelectric ink jet printer head of this embodiment, the common ink chambers 12a and 12b in the manifold plate 12 are provided.
A space 50 is provided adjacent to the common ink chambers 12a and 12b at the end (C in FIG. 7) where the cross-sectional area of
Since the rigidity of the manifold plate 12 at the position corresponding to each pressure chamber 16 is configured to be substantially equal, the stress applied from the pressure generating section via each pressure chamber 16 forms a common ink chamber in the manifold plate 12. It becomes almost uniform at the position corresponding to each pressure chamber of the member, and the ink discharge performance can be stabilized.

The common ink chambers 12a and 12b and the space chamber 50 in the manifold plate 12 according to the present embodiment can be formed by etching.
However, when the manifold plate 12 is formed using a resin, the common ink chambers 12a and 12b and the space chamber 50 can be formed by pressing, molding, or the like.

Further, in the above-described embodiment, the piezoelectric type pressure generating section of the piezoelectric actuator 20 is used. However, the present invention is not limited to this, and an electrostatic type pressure generating section may be used. You may.

As described above, the present invention has been described based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various improvements and modifications can be made without departing from the gist of the present invention. Can easily be inferred.

[0040]

As described above, according to the ink jet printer head of the first aspect, each pressure chamber of the member forming the common ink chamber is adjacent to the portion where the cross-sectional area of the common ink chamber is reduced. Since the pressure chamber is configured to provide a space chamber that substantially corrects the change in stiffness at the position corresponding to the pressure, the pressure applied to the ink in each of the pressure chambers from the pressure generating section is substantially equal in all the pressure chambers, so that the ink ejection Performance can be made uniform.

According to the ink jet printer head of the second aspect, the space chamber is provided in the same plane as the common ink chamber in the second plate member forming the common ink chamber. Since the stress applied from each of the pressure chambers through the pressure chambers becomes substantially uniform at the position corresponding to each pressure chamber of the member forming the common ink chamber in the second plate member, it is possible to achieve uniform ink ejection performance. it can.

According to the third aspect of the present invention, in a cross section at an arbitrary position in a direction orthogonal to the column direction formed by the plurality of pressure chambers, the sum of the cross sectional area of the common ink chamber and the cross sectional area of the space chamber is provided. Are substantially equal, the rigidity of the member forming the common ink chamber at the position corresponding to each pressure chamber can be made substantially equal, and therefore, the ink ejection performance can be made uniform.

[Brief description of the drawings]

FIG. 1 is a perspective view of a piezoelectric ink jet head with a nozzle side facing upward.

FIG. 2 is an exploded perspective view of components of the piezoelectric inkjet head.

FIG. 3 is an exploded perspective view of components of the piezoelectric inkjet head as viewed from above.

FIG. 4 is a bottom view of the bottom plate of the main body frame as viewed from below.

FIG. 5 is a perspective view of a front head unit.

FIG. 6 is a sectional view of a front head unit.

FIG. 7 is an exploded perspective view of a cavity plate.

FIG. 8 is an exploded enlarged perspective view of a cavity plate.

9 is an enlarged top view of an end (C part) of the manifold plate shown in FIG. 7;

FIG. 10 is an exploded enlarged perspective view of a piezoelectric actuator.

FIG. 11 is an enlarged top view of a conventional manifold plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body frame 4a, 4b, 4c, 4d Ink supply passage 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 50 Space chamber

Claims (3)

[Claims] A plurality of nozzles, a plurality of pressure chambers for supplying ink to the nozzles corresponding to each of the nozzles, and the plurality of pressure chambers for supplying the ink from an ink supply source through an ink supply hole. A common ink chamber that is distributed to the pressure chambers, and an actuator that includes a plurality of pressure generation units that apply pressure for discharging the ink to the pressure chambers corresponding to each of the pressure chambers, wherein the common ink chamber is , Located in a plane parallel to the plane formed by the plurality of pressure chambers,
And at least a part of the plurality of pressure chambers overlaps in a direction orthogonal to the surface, extends in a row direction formed by the plurality of pressure chambers, and further, the common ink chamber is at least an end separated from the ink supply source. In the part, in a direction away from the ink supply source, in an inkjet printer head having a shape whose cross-sectional area gradually decreases, adjacent to a portion where the cross-sectional area of the common ink chamber decreases,
A cavity plate in an ink jet printer head, wherein a space chamber is provided for substantially correcting a change in rigidity of a member forming the common ink chamber at a position corresponding to each of the pressure chambers. 2. A first plate member forming the plurality of pressure chambers and a second plate member forming the common ink chamber are laminated, and the space chamber is formed on the second plate member. 2. The ink jet printer head according to claim 1, wherein the ink jet printer head is formed in the same plane as the common ink chamber. 3. A cross-section at an arbitrary position in a direction orthogonal to a row direction formed by the plurality of pressure chambers, wherein a sum of a cross-sectional area of the common ink chamber and a cross-sectional area of the space chamber is substantially equal. The ink jet printer head according to claim 1 or 2, wherein