JP2000141652A - Head chip and head unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a head chip which protects a surface of a nozzle plate and improves a print quality and a durability, and a head unit using the same. SOLUTION: A head cap 28 is provided which is united to an outer side face of a joint body of a piezoelectric ceramic plate 11 and an ink chamber plate 17 and surrounds a nozzle plate 25 thereby protecting the nozzle plate 25. A face of the head cap 28 opposite to an object to be printed is projected from a face of the nozzle plate 25 opposite to the object to be printed.

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. 8 shows a schematic exploded view of an 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. A wiring substrate 120 is fixed to a surface of the piezoelectric ceramic plate 101 opposite to the nozzle plate 115 and opposite to the cover plate 107. A wiring 122 connected to each electrode 105 by a bonding wire 121 or the like is formed on the wiring substrate 120, and the electrode 105 is connected through the wiring 122.
Can be applied with a drive voltage.

In the recording head configured as described above, each groove 102 is filled with ink 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. 10, when ink is ejected from the nozzle opening 117 corresponding to the groove 102a, the groove 10
2a, a positive drive voltage is applied to the electrodes 105a and 105b, and the electrodes 105c and 105d facing each other are applied.
To ground. Thereby, the side walls 103a, 1
A driving electric field in the direction toward the groove 102a acts on 03b, and if this is perpendicular to the polarization direction of the piezoelectric ceramic plate 101, the side wall 103a,
103b is deformed in the direction of the groove 102a, the volume in the groove 102a decreases, the pressure increases, and ink is ejected from the nozzle opening 117.

Further, in such a recording head, the surface of the nozzle plate 115 facing the printing object is provided with a water-repellent liquid repellent in order to prevent the head from being stained by ink adhesion and the nozzle openings from being clogged. A water film is provided. Further, the head end surface is cleaned at predetermined intervals or at a desired time. Normally, this cleaning is performed by wiping the surface of the nozzle plate facing the printing material with a wiper formed of, for example, rubber having a relatively high hardness (Hs 40 to 50) and which does not swell.

[0008]

However, in the above-described structure, when cleaning the surface of the nozzle plate, the wiper directly contacts the nozzle plate. Peel off,
There is a problem that printing quality is deteriorated. In addition, the water-repellent film is particularly easily peeled off at the peripheral portion of the nozzle opening.

SUMMARY OF THE INVENTION In view of such circumstances, an object of the present invention is to provide a head chip which protects the surface of a nozzle plate and has improved printing quality and durability, and a head unit using the same.

[0010]

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. An ink chamber plate in which an ink chamber communicating with the groove is defined while sealing an opening of the groove; and sealing the one end surface of the piezoelectric ceramic plate and corresponding to each of the grooves. A nozzle plate having a nozzle opening, and applying a drive voltage to an electrode provided on a side wall in the groove to change the volume in the groove so that the ink filled therein can be filled in the nozzle opening. The head chip ejected from the nozzle plate is joined to the outer surface of the joined body of the piezoelectric ceramic plate and the ink chamber plate and surrounds the nozzle plate. Comprising a head cap for protecting the Le plate surface opposite to the substrate of the head cap is in the head chip, characterized in that protrudes from the surface facing the printing material of the nozzle plate.

According to a second aspect of the present invention, in the first aspect, the surface of the head cap facing the substrate is two to two times smaller than the surface of the nozzle plate facing the substrate.
The head chip is characterized by projecting 0 μm. A third aspect of the present invention is the head chip according to the first or second aspect, wherein the head cap is made of a metal material.

According to a fourth aspect of the present invention, there is provided the head chip according to any one of the first to third aspects, and a head holder mounting the head chip and mounting a driving circuit for the head chip. The feature is the head unit. A fifth aspect of the present invention is the head unit according to the fourth aspect, wherein the head holder can detachably hold an ink cartridge containing ink in the head holder.

According to the present invention, when the head is cleaned, the wiper does not come into strong contact with the nozzle plate more than necessary, and peeling of the water-repellent film is prevented.

[0014]

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 an embodiment, and FIG. 2 is an assembled perspective view and a sectional view thereof. As shown in FIGS. 1 and 2,
A plurality of grooves 12 are provided in the piezoelectric ceramic plate 11 in parallel, and each groove 12 is separated by a side wall 13.

One end of each groove 12 in the longitudinal direction extends to one end surface of the piezoelectric ceramic plate 11, and the other end does not extend to the other end surface, but gradually becomes shallower. Further, electrodes 15 for applying a driving electric field are formed on the opening side surfaces of both side walls 13 in each groove 12 in the longitudinal direction. Here, each groove 12 formed in the piezoelectric ceramic plate 11 is formed by, for example, a disk-shaped die cutter, and a portion whose depth is gradually reduced is formed using the shape of the die cutter. The electrode 15 formed in each groove 12 is formed, for example, by vapor deposition from a known oblique direction.

An ink chamber plate 17 is joined to the opening of the groove 12 of the piezoelectric ceramic plate 11. The ink chamber plate 17 includes an ink chamber 21 serving as a concave portion communicating with the other end of the groove 12 that is shallower.
1 has an ink supply port 22 penetrating in the opposite direction to the groove 12. Here, in the present embodiment, each groove 12
Are divided into groups corresponding to black (B), yellow (Y), magenta (M), and cyan (C) inks, and four ink chambers 21 and four ink supply ports 22 are provided respectively. ing.

The ink chamber plate 17 can be formed of a ceramic plate, a metal plate, or the like. However, in consideration of deformation after joining with the piezoelectric ceramic plate 11, a ceramic plate having a similar coefficient of thermal expansion is used. Is preferred. Also, the piezoelectric ceramic plate 11
A nozzle plate 25 is joined to an end face of the joined body of the nozzle body 17 and the ink chamber plate 17 where the groove 12 is open.
A nozzle opening 27 is formed at a position facing each groove 12 of the nozzle plate 25.

In the present embodiment, the nozzle plate 25 is
The groove 12 of the joined body of the piezoelectric ceramic plate 11 and the ink chamber plate 17 is formed to have the same area as the area 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.

The outer surface of such a nozzle plate 25,
And piezoelectric ceramic plate 11 and ink chamber plate 1
7 around the end where the groove 12 of the joined body is open,
In the present embodiment, a head cap 28 having an opening 28a large enough to fit with the nozzle plate 25 is arranged. The head cap 28 is for preventing the water-repellent film provided on the nozzle plate 25 from peeling off at the time of cleaning the head. The end face of the head cap 28 facing the printing object is a predetermined amount larger than the nozzle plate 25. L is provided so as to protrude.

The protrusion amount L of the head cap 28 may be appropriately determined according to the width W of the nozzle plate 25, but is preferably in the range of L = 2 to 20 μm, and more preferably smaller than 15 μm. Is preferred. In addition,
In the present embodiment, the protrusion amount L = 8 μm with respect to the width W of the nozzle plate = 1.6 mm. In addition, since the head cap 28 and the nozzle plate 25 are aligned with relatively high accuracy in this manner, the head cap 28
Is preferably formed of a material having high rigidity, for example, a metal material or the like.

The head cap 28 may be an integrally molded product as shown in the figure, or may be, for example, one that can be divided into two. With such a configuration, when the surface of the nozzle plate 25 is wiped with a wiper or the like, the wiper does not contact the nozzle plate 25 more strongly than necessary.
The water-repellent film provided on the surface of the nozzle plate 25 can be prevented from peeling off, and the surface of the nozzle plate 25 can be surely wiped off.

The head chip 30 having the above-described structure includes the piezoelectric ceramic plate 11 and the ink chamber plate 1.
7 and a nozzle plate 25 is attached to the end face of the joined body.
To join. Next, the outer surface of the nozzle plate 25, the piezoelectric ceramic plate 11 and the ink chamber plate 17
It is formed by fitting and bonding the head cap 28 to the joined body.

In fitting and bonding the head cap 28, it is necessary to align the surfaces of both the nozzle plate 25 and the head cap 28. This method is not particularly limited, but in the present embodiment, the positioning is performed as follows. First, as shown in FIG. 3A, protective films 60A and 60B having a predetermined thickness are attached to the end surfaces of the nozzle plate 25 and the head cap 28 on the side facing the printing material. At this time, the end face of the nozzle plate 25
A protective film 60A that is thicker than the protective film 60B of the head cap 28, that is, is thicker by an amount that protrudes the head cap 28 is formed. The material of the protective film is not particularly limited.

Next, as shown in FIG. 3B, the head cap is set so that the surfaces of the protective films 60A and 60B of the nozzle plate 25 and the head cap 28 are the same, that is, both surfaces are flush. 28 is fitted and bonded to the outer surface of the nozzle plate 25. After that, as shown in FIG. 3C, the protective films 60A and 60B are removed. Through the above steps, the end face of the head cap 28 and the end face of the nozzle plate 25 can be easily aligned.

The principle of driving such a head chip is the same as that described in the prior art, and a description thereof will be omitted. Further, there is no particular limitation on how to provide wirings and the like for driving such a head chip 30, but an example is shown below. 4 and 5 show an example of a manufacturing process in which the above-described head chip 30 is used as the head chip unit 40.

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.
A flexible cable 32 is joined to this wiring pattern via an anisotropic conductive film 31. An aluminum base plate 33 on the piezoelectric ceramic plate 11 side and a head cover 34 on the ink chamber plate 17 side are attached to the rear end side of the head cap 28 of the joined body of the piezoelectric ceramic plate 11 and the ink chamber plate 17. Can be 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
The two sandwich the joined body of the piezoelectric ceramic plate 11 and the ink chamber plate 17. The head cover 34 is provided with an ink introduction path 35 communicating with each of the ink supply ports 22 of the ink chamber plate 17.

Next, as shown in FIG. 5A, a wiring board 36 is fixed on a base plate 33 protruding to 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. Thereby, the head chip unit 40 of FIG. 5B is completed.

Further, such a head chip unit 40 is used, for example, by being assembled to a tank holder for detachably holding 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). Further, on the upper surface of the bottom wall, there is provided a connecting portion 42 which is connected to an ink supply port which is an opening formed at the bottom of the ink cartridge. The connection unit 42 is provided for each color ink of black (B), yellow (Y), magenta (M), and cyan (C), for example. Communication part 42
An ink flow path (not shown) is formed therein, and a filter 43 is provided at the end of the connecting portion 42 which is an opening thereof. The ink flow path formed in the connection portion 42 is formed to communicate with the back side of the bottom wall, and each ink flow path is not shown in the flow path substrate 45 provided on the back side of the tank holder 41. It communicates with the head connection port 46 that opens on the side wall of the flow path substrate 45 via the ink flow path. This head connection port 4
Reference numeral 6 denotes an opening on the side surface of the tank holder 41, and a head chip unit holding portion 47 for holding the above-described head chip unit 40 is provided at the bottom of the side wall. 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 40 in the surrounding wall 48. Further, an engaging shaft 49 that engages with the locking hole 40a provided in the wiring board 36 is provided upright.

Therefore, the head chip 40 is mounted on the head chip unit holding portion 47 and the head unit 50 is mounted.
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. Thereby, the connecting portion 4 of the tank holder 41
The ink introduced from the ink cartridge through the ink passage 2 is introduced into the ink introduction passage 35 of the head chip unit 40 through the ink passage in the passage substrate 45, and is filled in the ink chamber 22 and the groove 12.

Such a head unit 50 is used, for example, mounted on a carriage of an ink jet recording apparatus. FIG. 7 schematically shows an example of this use mode. As shown in FIG. 7, the carriage 61 is mounted on a pair of guide rails 62a and 62b so as to be movable in the axial direction. When,
The sheet is conveyed via a timing belt 65 stretched over a pulley 64b provided on the other end side. Carriage 61
Guide rails 6 on both sides in the direction orthogonal to
A pair of transport rollers 66 are respectively provided along 2a and 62b.
And 67 are provided. These transport rollers 66 and 67 are provided below the carriage 61.
The recording medium S is transported in a direction orthogonal to the transport direction of the recording medium S.

The above-described head unit 50 is mounted on the carriage 61, and the above-described ink cartridge can be detachably attached to the head unit 50. According to such an ink jet recording apparatus, the carriage 61 is scanned in the direction perpendicular to the feeding direction while feeding the recording medium S, so that characters and images can be recorded on the recording medium S by the head chip. it can.

Although one embodiment has been described above, the present invention is not limited to such a configuration.

[0033]

As described above, in the present invention, the head cap surrounding the periphery of the nozzle plate is provided so that the surface of the head cap that faces the printing material protrudes from the surface of the nozzle plate. Therefore, when the surface of the nozzle plate is wiped off with a wiper or the like, the wiper does not come into strong contact with the nozzle plate more than necessary, and the water-repellent film provided on the surface of the nozzle plate can be prevented from peeling off. Thereby, there is an effect that the print quality and the durability of the head can be improved.

[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 an assembled perspective view and a sectional view of a head chip according to an embodiment of the present invention.

FIG. 3 is a perspective view showing assembly of a unit using a head chip according to one embodiment of the present invention.

FIG. 4 is a cross-sectional view schematically showing a process of assembling a head chip according to an 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 assembling of a unit using a head chip according to one embodiment of the present invention.

FIG. 7 is a perspective view showing a use mode of a unit using a head chip according to one embodiment of the present invention.

FIG. 8 is an exploded perspective 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.

FIG. 10 is a cross-sectional view illustrating an outline of a recording head according to a conventional technique.

[Explanation of symbols]

 Reference Signs List 11 piezoelectric ceramic plate 12 groove 13 side wall 15 electrode 17 ink chamber plate 25 nozzle plate 27 nozzle opening 28 head cap 28a opening 30 head chip unit 33 base plate 34 head cover 35 ink introduction path 36 wiring board 41 tank holder 42 connecting part 45 flow path Substrate 50 Head unit

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 2C056 EA21 EA22 FA04 JA03 KC01 KC22 2C057 AF65 AF93 AG01 AG12 AG45 AP02 AP24 BA03 BA14

Claims (5)

[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. An ink chamber plate in which an ink chamber is defined, and a nozzle plate that seals the one end surface of the piezoelectric ceramic plate and has a nozzle opening corresponding to each of the grooves. A head chip that changes a volume in the groove by applying a driving voltage to the provided electrode and discharges ink filled in the groove from the nozzle opening; and joining the piezoelectric ceramic plate and the ink chamber plate. A head cap joined to the outer surface of the body to surround the nozzle plate and protect the nozzle plate; Surface opposite to the substrate of the cap, the head chip, characterized in that protrudes from the surface facing the printing material of the nozzle plate. 2. The head chip according to claim 1, wherein a surface of the head cap facing the printing material protrudes by 2 to 20 μm from a surface of the nozzle plate facing the printing material. 3. The head chip according to claim 1, wherein the head cap is made of a metal material. 4. 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 drive circuit for the head chip is mounted. 5. The head unit according to claim 4, wherein an ink cartridge containing ink is detachably held in the head holder.