JP2001219561A - Head chip and head unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a head chip for manufacturing a long recording head with high accuracy at low cost and a head unit employing it. SOLUTION: This head chip comprises a piezoelectric ceramic plate 11 having a plurality of grooves 12 opening to one side and one end face, a cover plate 17 bonded to one side of the piezoelectric ceramic plate 11 to seal the opening of the grooves 12 and defining ink chambers communicating with the grooves 12, and a nozzle plate 25 for sealing the one end face of the piezoelectric ceramic plate 11 and having nozzle openings 27 corresponding to respective grooves 12 wherein the inner volume of the groove 12 is varied by applying a drive voltage to an electrode 15 provided on the side wall 13 of the groove 12 and ink filling the groove 12 is ejected from the nozzle opening 27. The piezoelectric ceramic plate 11 comprises a plurality of piezoelectric ceramic substrates 11a-11c bonded in the longitudinal direction of the groove 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a head chip mounted on an ink jet recording apparatus applied to, for example, a printer or a facsimile, and a head unit using the same.

[0002]

2. Description of the Related Art Conventionally, there has been known an ink jet recording apparatus for recording characters and images on a recording medium by using a recording head which discharges ink from a plurality of nozzles. In such an ink jet recording apparatus, a recording head facing a recording medium is provided on a head holder, and the head holder is mounted on a carriage and scanned in a direction orthogonal to a transport direction of the recording medium.

FIG. 7 shows a schematic exploded view of one example of such a recording head, and FIG. As shown in FIGS. 7 and 8, a plurality of grooves 102 are provided in the piezoelectric ceramic plate 101, and each groove 102 is separated by a side wall 103. One end of each groove 102 in the longitudinal direction extends to one end surface of the piezoelectric ceramic plate 101, and the other end does not extend to the other end surface, but gradually decreases in depth. Further, electrodes 105 for applying a driving electric field are formed on the opening side surfaces of both side walls 103 in each groove 102 in the longitudinal direction.

[0004] Groove 102 of piezoelectric ceramic plate 101
A cover plate 107 is joined to the opening side of the cover via an adhesive 109. The cover plate 107 has an ink chamber 111 serving as a recess communicating with the shallow other end of each groove 102, and a groove 102 from the bottom of the ink chamber 111.
And an ink supply port 112 penetrating in the opposite direction.

A nozzle plate 115 is joined to an end face of the joined body of the piezoelectric ceramic plate 101 and the cover plate 107 where the groove 102 is open.
A nozzle opening 117 is formed at a position facing each groove 102 of the nozzle plate 115.

The cover plate 107 is located on the side of the piezoelectric ceramic plate 101 opposite to the nozzle plate 115.
The wiring board 120 is fixed to the surface on the opposite side to the above. A wiring 122 connected to each electrode 105 by a bonding wire 121 or the like is formed on the wiring substrate 120, and a driving voltage can be applied to the electrode 105 via the wiring 122.

In the recording head configured as described above, ink is filled into each groove 102 from the ink supply port 112,
When a predetermined driving electric field is applied to the side walls 103 on both sides of the predetermined groove 102 via the electrode 105, the side wall 103 is deformed and the volume in the predetermined groove 102 is changed.
02 is ejected from the nozzle opening 117.

For example, as shown in FIG. 9, when ink is ejected from the nozzle opening 117 corresponding to the groove 102a, a positive drive voltage is applied to the electrodes 105a and 105b in the groove 102a and the electrodes 105a and 105b face each other. Electrode 10
5c and 105d are grounded. As a result, a driving electric field is applied to the side walls 103a and 103b in a direction toward the groove 102a, and the driving electric field is applied to the piezoelectric ceramic plate 101.
Perpendicular to the polarization direction of the groove 103a, the side walls 103a and 103b are deformed in the direction of the groove 102a due to the piezoelectric thickness-shear effect.
02a decreases, the pressure increases and the nozzle opening 1
17 ejects ink.

[0009]

However, it is difficult to manufacture the piezoelectric ceramic plate constituting the above-described recording head in a relatively large size. When manufacturing a long so-called line printer or the like, A plurality of recording heads must be shifted in a direction intersecting with the row direction of the nozzle openings, and must be arranged in a so-called staggered manner.

Further, since a plurality of recording heads must be aligned, there is a problem that the relative positional accuracy of the nozzle openings is low.

In view of such circumstances, an object of the present invention is to provide a head chip capable of manufacturing a long recording head at low cost and with high accuracy, and a head unit using the same.

[0012]

According to a first aspect of the present invention, there is provided a piezoelectric ceramic plate having a plurality of grooves formed on one surface and one end surface, and the one surface of the piezoelectric ceramic plate. A cover plate that is joined to seal the opening of the groove and defines an ink chamber that communicates with the groove, and seals the one end surface of the piezoelectric ceramic plate and corresponds to each of the grooves. A nozzle plate having a nozzle opening, and changing the volume in the groove by applying a driving voltage to an electrode provided on a side wall in the groove to change the volume of the ink in the groove from the nozzle opening. In the head chip for discharging, the piezoelectric ceramic plate is composed of a plurality of piezoelectric ceramic substrates joined in a longitudinal direction of the groove. In the Dochippu.

According to a second aspect of the present invention, there is provided a head chip according to the first aspect, wherein the groove is formed at a joint where the plurality of piezoelectric ceramic substrates are joined.

According to a third aspect of the present invention, there is provided a head chip according to the second aspect, wherein the groove formed in the joint is a dummy groove which is not actually used.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the piezoelectric ceramic plate is thinly cut in a thickness direction after the piezoelectric ceramic substrate is joined. On the chip.

According to a fifth aspect of the present invention, there is provided a head chip according to any one of the first to fourth aspects, and a head holder mounting the head chip and mounting a drive circuit for the head chip. Head unit.

A sixth aspect of the present invention is the head unit according to the fifth aspect, wherein the head holder is capable of detachably holding an ink cartridge containing ink.

According to the present invention, a long recording head can be manufactured at low cost, and stable printing quality can be maintained.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments of the present invention.

FIG. 1 is an exploded perspective view of a head chip according to one embodiment, and FIG. 2 is a sectional view thereof. As shown in the drawing, a plurality of grooves 12 are provided in a piezoelectric ceramic plate 11 constituting a head chip 10 of the present embodiment, and each groove 12 is separated by a side wall 13. Each groove 12
Has one end in the longitudinal direction extending to one end of the piezoelectric ceramic plate 11, and the other end does not extend to the other end but has a gradually decreasing depth. In addition, each groove 12
On the opening side surface of both side walls 13 in the longitudinal direction,
An electrode 15 for applying a driving electric field is formed.

The head chip 10 of the present embodiment is
The piezoelectric ceramic plate 11 is used for a long so-called line inkjet head. The piezoelectric ceramic plate 11 has, for example, an A4 size paper width and a width of about 210 mm. The grooves 12 formed in the piezoelectric ceramic plate 11 are provided at a relatively high density, for example, about 180 dpi at intervals of, for example, about 141.1 μm. Such a piezoelectric ceramic plate 11 is composed of a plurality of, in this embodiment, three, piezoelectric ceramic substrates 11a to 11c joined along the longitudinal direction of the groove 12.

Here, as shown in FIG. 2, it is preferable that a groove 12 is formed in the joint 16 where the piezoelectric ceramic substrates 11a to 11c constituting the piezoelectric ceramic plate 11 are joined. Therefore, the width dimension of each of the piezoelectric ceramic substrates 11a to 11c is adjusted with relatively high accuracy.

The method for manufacturing such a piezoelectric ceramic plate 11 is not particularly limited, but in the present embodiment, it was formed as follows.

First, as shown in FIG. 3A, a plurality of blocks 90 are formed in the present embodiment to be the respective piezoelectric ceramic substrates 11a to 11c. Each block 90
Have the same dimensions in the present embodiment, and have a thickness greater than a desired thickness of the piezoelectric ceramic substrates 11a to 11c. For example, in the present embodiment, the piezoelectric ceramic substrates 11a to 11c are formed with a thickness of about 0.8 mm, whereas the blocks 90 are formed with a thickness of about 5 to 7 mm.

Next, as shown in FIG. 3 (b), the end faces to be the joining surfaces of the three blocks 90 are polished to flatten the joining surfaces and to form the dimensions in the width direction with relatively high precision. I do. This is because the bonding surface is flattened to increase the bonding strength, and as described above, each of the piezoelectric ceramic substrates 11a to 11
This is because the groove 12 is formed in the joint 16 of FIG. After polishing the end surface in this manner, each block 90 is bonded and fixed with, for example, an epoxy adhesive.

Next, as shown in FIG. 3C, the plurality of bonded blocks 90 are thinly cut into a plurality of pieces in the thickness direction to form a piezoelectric ceramic plate 11 composed of piezoelectric ceramic substrates 11a to 11c.

Thereafter, each groove 12 is formed in the piezoelectric ceramic plate 11 by, for example, a disk-shaped die cutter, and the electrode 15 is formed in each groove 12 by, for example, evaporation from a known oblique direction. The portion where the depth of each groove 12 is gradually reduced is formed using the shape of a die cutter.

A cover plate 17 is joined to the opening side of the groove 12 of the piezoelectric ceramic plate 11. The cover plate 17 has an ink chamber 21 serving as a recess communicating with the shallow other end of each groove 12, and an ink supply port 22 penetrating from the bottom of the ink chamber 21 in a direction opposite to the groove 12. .

The cover plate 17 can be formed of a ceramic plate, a metal plate, or the like. However, in consideration of deformation after bonding with the piezoelectric ceramic plate 11, a ceramic plate having a similar coefficient of thermal expansion is used. Is preferred.

A nozzle plate 25 is joined to an end surface of the joined body of the piezoelectric ceramic plate 11 and the cover plate 17 where the groove 12 is open, and is located at a position facing each groove 12 of the nozzle plate 25. Is nozzle opening 2
7 are formed.

In this embodiment, the nozzle plate 25 is
The groove 12 of the joined body of the piezoelectric ceramic plate 11 and the cover plate 17 is larger than the size of the open end face. The nozzle plate 25 has a nozzle opening 27 formed in a polyimide film or the like by using, for example, an excimer laser device. Although not shown, a water-repellent film having a water-repellent property is provided on the surface of the nozzle plate 25 facing the printing material in order to prevent ink from adhering.

In this embodiment, the nozzle support plate 28 is provided around the end of the joined body of the piezoelectric ceramic plate 11 and the cover plate 17 where the groove 12 is open.
Is arranged. The nozzle support plate 28 is joined to the outside of the end face of the joined body of the nozzle plate 25 to stably hold the nozzle plate 25. Of course, the nozzle support plate 28 need not be provided.

The head chip 10 having the above-described structure includes a piezoelectric ceramic plate 11 and a cover plate 17.
And the nozzle plate 25 is joined to the end surface of the joined body. Next, the nozzle support plate 28 is fitted and bonded to the outer surface of the nozzle plate 25 and the joined body of the piezoelectric ceramic plate 11 and the cover plate 17.

The head chip 10 of the present embodiment as described above
Since the piezoelectric ceramic plate 11 is formed by joining a plurality of piezoelectric ceramic substrates 11a to 11c, a long head chip can be formed with high precision and can be provided at low cost. Further, since the groove 12 is formed in the joint portion 16 of each of the piezoelectric ceramic substrates 11a to 11c, even when a voltage is applied, the joint portion 16 is formed.
Is not deformed, and there is no possibility of adversely affecting ink ejection.

In the present embodiment, the piezoelectric ceramic plates 11 are formed by joining the piezoelectric ceramic substrates 11a to 11c having substantially the same size. However, the present invention is not limited to this.

In this embodiment, three piezoelectric ceramic substrates are joined to form a piezoelectric ceramic plate. However, the number is not limited. For example, four or more sheets may be joined. Alternatively, of course, two piezoelectric ceramic substrates may be joined.

Although there is no particular limitation on the manner in which wirings and the like for driving such a head chip 10 are provided, an example is shown below.

FIGS. 4 and 5 show an example of a manufacturing process in which the above-described head chip 10 is used as the head chip unit 30. FIG.

As shown in FIG. 4, a wiring pattern (not shown) connected to the electrode 15 is formed at the end of the piezoelectric ceramic plate 11 opposite to the nozzle opening side.
The flexible cable 32 is joined to this wiring pattern via an anisotropic conductive film 38. On the rear end side of the nozzle support plate 28 of the joined body of the piezoelectric ceramic plate 11 and the cover plate 17, an aluminum base plate 33 on the piezoelectric ceramic plate 11 side is provided.
The head cover 34 on the cover plate 17 side is assembled. The base plate 33 and the head cover 34
The head cover 34 is inserted into the locking hole 33a of the base plate 33.
Is fixed by engaging the locking shaft 34a of
Both the piezoelectric ceramic plate 11 and the cover plate 1
7 is sandwiched. The head cover 34 is provided with an ink introduction path 35 communicating with each of the ink supply ports 22 of the cover plate 17.

Next, as shown in FIG. 5A, a wiring board 36 is fixed on a base plate 33 protruding from the rear end side of the piezoelectric ceramic plate 11. Here, a drive circuit 37 such as an integrated circuit for driving a head chip is mounted on the wiring board 36, and the drive circuit 37 and the flexible cable 32 are connected via an anisotropic conductive film 38. Thus, the head chip unit 30 shown in FIG. 5B is completed.

Further, such a head chip unit 30 is used, for example, by assembling it with a tank holder which detachably holds an ink cartridge.

FIG. 6 shows an example of such a tank holder. The tank holder 41 shown in FIG. 6 has a substantially box shape with one side opened, and is capable of detachably holding an ink cartridge (not shown). Also, on the bottom wall upper surface,
A connecting portion 42 is provided for connecting to an ink supply port which is an opening formed at the bottom of the ink cartridge. An ink channel (not shown) is formed in the communication portion 42,
A filter 43 is provided at the distal end of the connecting portion 42 serving as the opening. The ink flow path formed in the connection portion 42 is formed to communicate with the back side of the bottom wall. Each ink flow path is not shown in the flow path substrate 45 provided on the back side of the tank holder 41. Flow path substrate 45 via ink flow path
Communicates with the head connection port 46 that opens on the side wall of the head. The head connection port 46 opens on the side of the tank holder 41,
The head chip unit 3 described above is provided at the bottom of the side wall.
A head chip unit holding section 47 for holding 0 is provided. The head chip unit holding portion 47 includes a substantially U-shaped surrounding wall 48 surrounding the drive circuit 37 provided on the wiring board 36, and a base plate 33 of the head chip unit 30 in the surrounding wall 48. Further, an engagement shaft 49 that engages with the locking hole 30a provided in the wiring board 36 is provided upright.

Accordingly, the head chip unit 30 is mounted on the head chip unit holding section 47, and the head unit 40 is completed. At this time, the ink introduction path 35 formed in the head cover 34 is connected to the head connection port 46 of the flow path substrate 45. As a result, the ink introduced from the ink cartridge via the connection portion 42 of the tank holder 41 is introduced into the ink introduction passage 35 of the head chip unit 30 through the ink passage in the passage substrate 45, and the ink chamber 21 And filled in the groove 12.

When a predetermined driving electric field is applied to the side walls 13 on both sides of the predetermined groove 12 via the electrode 15 as described in the prior art, the side wall 13 is deformed and the predetermined groove 1 is formed.
2 changes, whereby the ink in the groove 12 is ejected from the nozzle opening 27.

The embodiment of the present invention has been described above, but the present invention is not limited to such a configuration.

For example, in the present embodiment, the head chip and the head chip unit configured to discharge a single color ink are illustrated. However, the present invention is not limited to this. May be discharged.

[0047]

As described above, according to the present invention, the piezoelectric ceramic plate constituting the head chip is formed by a plurality of piezoelectric ceramic substrates joined in the longitudinal direction of the groove. Can be formed without arranging them in a staggered pattern, so that the long recording head can be reduced in size and manufactured at low cost.

Further, since all the nozzle openings can be formed in one line in one nozzle plate, the relative positional accuracy of the nozzle openings can be remarkably improved, and stable printing quality can be maintained. To play.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a head chip according to an embodiment of the present invention.

FIG. 2 is a sectional view of a head chip according to an embodiment of the present invention.

FIG. 3 is a perspective view showing a manufacturing process of a piezoelectric ceramic plate constituting a head chip.

FIG. 4 is an exploded perspective view of a unit using a head chip according to one embodiment of the present invention.

FIG. 5 is a perspective view showing an assembly of a unit using a head chip according to one embodiment of the present invention.

FIG. 6 is a perspective view showing an assembly of a unit using a head chip according to one embodiment of the present invention.

FIG. 7 is an exploded perspective view showing an outline of a recording head according to the related art.

FIG. 8 is a cross-sectional view showing an outline of a recording head according to a conventional technique.

FIG. 9 is a cross-sectional view illustrating an outline of a recording head according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Head chip 11 Piezoelectric ceramic plate 11a-11c Piezoelectric ceramic substrate 12 Groove 13 Side wall 15 Electrode 17 Cover plate 25 Nozzle plate 27 Nozzle opening 30 Head chip unit 40 Head unit

Claims (6)

[Claims] 1. A piezoelectric ceramic plate having a plurality of grooves formed on one surface and one end surface, and joined to the one surface of the piezoelectric ceramic plate to seal an opening of the groove and communicate with the groove. A cover plate in which an ink chamber is defined, and a nozzle plate sealing the one end surface of the piezoelectric ceramic plate and having a nozzle opening corresponding to each of the grooves, provided on a side wall in the groove. In a head chip that changes the volume in the groove by applying a driving voltage to the applied electrode and discharges the ink filled therein from the nozzle opening, the piezoelectric ceramic plate is disposed in the longitudinal direction of the groove. A head chip comprising a plurality of bonded piezoelectric ceramic substrates. 2. The head chip according to claim 1, wherein the groove is formed at a joint where the plurality of piezoelectric ceramic substrates are joined. 3. The head chip according to claim 2, wherein the groove formed in the joint is a dummy groove that is not actually used. 4. The head chip according to claim 1, wherein the piezoelectric ceramic plate is cut in a thickness direction after bonding the piezoelectric ceramic substrate. 5. A head unit comprising: the head chip according to claim 1; and a head holder on which the head chip is mounted and on which a driving circuit for the head chip is mounted. 6. The head unit according to claim 5, wherein an ink cartridge containing ink is detachably held in the head holder.