JPH08290569A - Ink jet recorder - Google Patents

Abstract

PURPOSE: To perform the high density disposition and high frequency response of nozzles by injecting the ink of an ink chamber from the nozzle by displacing the inserting part of a pressurizing member toward the nozzle. CONSTITUTION: A piezoelectric element 32 applied by a voltage is restricted for the deformation in the area fixed to a support plate 30, abruptly elongation deformed at the inserting part extended mainly into an ink chamber 23, and displaced at the end face toward a nozzle hole 27. The ink charged in the chamber 23 is so pressurized by the displacement as to be pressed by a piston, flown in a droplet state from the hole 27, and stuck on a record sheet. When the voltage is eliminated to individual electrodes 34, the element 32 is returned to the original state. At this time, negative pressure is generated in the chamber 23, and the ink is supplied to the chamber 23 via an ink manifold 29 and an ink supply port 22. With this structure, the high density disposition and high frequency response of the nozzles are performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus for recording on a recording medium such as paper by ejecting ink droplets according to an image signal.

[0002]

2. Description of the Related Art Conventionally, a voltage is applied to a piezoelectric body in response to an image signal, and ink is pressed based on the deformation of the piezoelectric body to eject ink droplets from a nozzle, thereby recording on a recording medium such as paper. Inkjet heads are used in recording devices such as printers.

As the ink jet head, for example, a circular diaphragm having a bimorph structure in which a metal film is sandwiched between piezoelectric materials and electrode layers are formed on the upper and lower surfaces of the piezoelectric material is arranged in each ink chamber, and a voltage is applied via the electrode layers. A Kaiser type inkjet head that applies a pressure to deform the vibration plate and ejects the ink filled in the ink chamber under pressure based on this deformation is well known (US Pat.
946, 398).

[0004]

However, in the above-mentioned Kaiser type ink jet head, it is necessary to use a vibrating plate having a large operating area in order to cause the circular vibrating plate having a bimorph structure to act and eject ink. In addition to the difficulty of high-density arrangement of ink chambers,
When ejecting ink continuously from one ink chamber, it is necessary to wait until the diaphragm returns to its original state in order to stabilize the ejected ink droplet diameter, but circular vibration with a large operating area It takes a long time for the plate to undergo damped vibration and to be restored, resulting in poor responsiveness. Therefore, there is a problem in that the ink chambers are structurally unsuitable for increasing the printing speed by arranging the ink chambers at a high density to increase the number of nozzles or by applying a high frequency voltage to the diaphragm.

Therefore, the present invention has been made to solve the above problems, and an object of the present invention is to provide an ink jet recording apparatus which is easy to realize high density arrangement of multiple nozzles and has excellent high frequency response.

[0006]

In order to achieve the above object, the ink jet recording apparatus of the present invention comprises a plurality of ink chambers each formed by being surrounded by a non-piezoelectric member, each of which is elongated and elongated, and the length of the ink chamber. A plurality of nozzle portions provided on one end side in the direction and corresponding to each ink chamber, and at least a portion is inserted into each ink chamber portion from the other end side in the longitudinal direction of the ink chamber, and the inserted portion is a piezoelectric body or a piezoelectric body. A pressure member formed of a non-piezoelectric material connected to the body and having a cross section slightly smaller than the cross section of the ink chamber, and a voltage is applied to the piezoelectric body of the pressure member according to an image signal. By applying a voltage to the piezoelectric body by the voltage applying means to deform the piezoelectric body and displacing the insertion portion of the pressing member toward the nozzle portion based on the deformation. The ink filled in the chamber is obtained so as to inject from the nozzle portion.

In the ink chamber, groove-shaped recesses that extend in parallel to the first non-piezoelectric member are formed, and the second non-piezoelectric member that covers each recess is fixed to the recess forming surface so that the inside of each recess is fixed. Although it is formed, the ink chamber may be formed by penetrating the inside of one non-piezoelectric member by injection molding using a punching die or perforation. By doing so, the number of parts and the number of assembly steps are reduced. There are advantages.

The nozzle portion is formed by covering the one end side in the longitudinal direction of the ink chamber with a nozzle plate having a nozzle hole formed corresponding to each ink chamber, but narrowing the cross section on the one end side of the ink chamber. The nozzle portion may be formed integrally with the ink chamber.

It is preferable that the piezoelectric body of the pressure member is formed in a so-called comb tooth shape, which is connected to each other by a connecting portion at a portion other than that corresponding to the ink chamber, but is divided for each ink chamber. Piezoelectric materials can also be used.

[0010]

In the above ink jet recording apparatus, when a voltage is applied to the piezoelectric body of the pressure member by the voltage applying means, when the inserted portion into each ink chamber is formed of the piezoelectric body, the inserted portion itself, and When the insertion portion is made of a non-piezoelectric material, the piezoelectric body connected to the non-piezoelectric material expands and deforms along the longitudinal direction of the ink chamber.
Based on this deformation of the piezoelectric body, the insertion portion is abruptly displaced toward the nozzle portion, and the displacement causes the ink filled in the ink chamber to be pressurized and fly as an ink droplet from the nozzle portion. On the other hand, when the voltage application to the piezoelectric body of the pressurizing member is released, the piezoelectric body is restored and the insertion portion in the ink chamber returns to the original state. At this time, negative pressure is generated in the ink chamber,
As a result, ink is replenished in the ink chamber, and preparation for the next ink flight is possible.

When the ink is ejected, the pressure member, which is inserted with a slight clearance from the wall surface of the ink chamber, presses the ink so that it is pushed by the piston.
Moreover, since the pressurizing direction and the ink jetting direction are the same, efficient and stable ink jetting can be obtained with a small displacement of the insertion portion. Further, when the insertion portion is formed of a non-piezoelectric material, the piezoelectric body connected to the non-piezoelectric material is arranged outside the ink chamber and does not come into direct contact with the ink, so that the ink penetrates and the resistance is reduced. There is nothing to do.

Further, in the ink jet recording apparatus in which the piezoelectric body of the pressure member is formed in a so-called comb shape, the structural strength of each piezoelectric body corresponding to each ink chamber is increased, and the handling in the processing / assembly surface is improved. Easy,
Assembling variation is reduced and accuracy is improved.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 schematically shows the overall configuration of an inkjet recording device 1 according to the present invention.
The inkjet recording apparatus 1 is roughly classified into a connector 2
a, a power supply unit 2, a drive system 3, a mechanical controller 4, a memory 5, a controller 6, and an ink supply unit 7.
, Scan carriage 8, paper feed unit 9, and case 10
And an operation panel 11. The scan carriage 8 is capable of scanning in a direction orthogonal to the paper passing direction (direction of arrow a) (front and back direction of the paper surface in FIG. 1), and inside the carriage 4 is provided for each color of black, cyan, magenta and yellow. Two inkjet heads 12
Are arranged along the sheet passing direction, and the ink discharge nozzles are directed downward.

As shown in FIG. 2, the ink jet head 12 has a top plate 20 made of, for example, alumina as a first non-piezoelectric member. A plurality of groove-shaped recesses 21 are formed on the lower surface of the top plate 20 by dicing or the like. These recesses 21 are arranged at a predetermined pitch in the width direction of the top plate 20 (left and right direction in FIG. 2) and at the same time as the top plate 2.
It is formed over the longitudinal direction of 0 (the depth direction in FIG. 2).

As with the top plate 20, a substrate 24 as a second non-piezoelectric member made of, for example, alumina is fixed to the surface of the top plate 20 on which the recess 21 is formed by an adhesive or the like. A plurality of ink chambers 2 each elongated in the recess 21 surrounded by the top plate 20 on all sides.
3 is formed. Further, the joined body of the top plate 20 and the substrate 24 is installed on the second substrate 25.

As shown in FIG. 3, a nozzle plate 26 made of, for example, a polyimide film having a thickness of 25 to 200 μm is fixed to the front end surface of the joined body of the top plate 20 and the substrate 24. A plurality of nozzle holes 27 are formed in the nozzle plate 26 by, for example, an excimer laser so as to correspond to the ink chambers 23, and the pitch thereof is, for example, about 42.3 to 254 μm (pixel density: 600 to 100 dp).
i) about the same. Further, the nozzle hole 27 is preferably formed in a tapered shape so that its cross-sectional area is large on the ink chamber 23 side and small on the side facing the outside. This is because it has the effect of making it difficult for air to be sucked from the nozzle holes 27 into the ink chamber 23 when the ink is replenished after the ink has flown.

A plurality of ink supply ports 22 communicating with the ink chambers 23 are formed in each of the recesses 21 of the top plate 20, and one or a plurality of ink supply ports 22 are provided on the upper portion so as to cover the ink supply ports 22. An ink manifold 29 is provided by protruding the ink tube 28 of FIG.

On the second substrate 25, a plate-like support plate 30 slightly thicker than the substrate 24 is installed at an appropriate distance from the substrate 24, and the support plate 3 is provided.
The pressure member 31 is fixed to the upper part of the ink chamber side of No. 0 by an adhesive method or the like. As shown in FIG. 4, the pressure member 31 is formed in a so-called comb shape, and connects the piezoelectric bodies 32 formed corresponding to the ink chambers 23 and one end side of each piezoelectric body 32, respectively. And a connecting portion 33. The piezoelectric body 32 has a columnar shape elongated in the direction along the ink chamber 23. As shown in FIG. 3, the tip end portion is inserted into each ink chamber 23 from the rear end side in the longitudinal direction of the ink chamber 23. Has been done. The periphery of the piezoelectric body 32 located at the rear end opening of the ink chamber 23 is sealed with a sealing material 36 made of, for example, fluorosilicone rubber to prevent ink leakage.

The portion where the piezoelectric body 32 is inserted is the ink chamber 23.
It is preferable that it is formed so as to have a slightly smaller cross section and have a distance of 30 μm or less from the inner wall surface of the ink chamber 23. This is to prevent the ink flying efficiency from decreasing due to the ink flowing around between the insertion portion and the inner wall surface of the ink chamber 23 when the ink is pressurized. In addition, at least the insertion portion of the piezoelectric body 32, which is constantly in contact with ink, has low resistance due to ink permeation and no effective voltage is applied, and the amount of deformation of the piezoelectric body, that is, the front end surface of the insertion portion. In order to prevent the displacement amount of the ink from decreasing, for example, it is preferable to apply a polyimide resin by a spin coating method and perform an overcoat treatment by baking at 180 ° C. for 1 hour. When used on the body, this process may be omitted.

An individual electrode 34 is formed on the upper surface of each piezoelectric body 32.
However, common electrodes 35 are formed on the lower surface of the piezoelectric body 32, respectively. The common electrode 35 of each piezoelectric body 32 is made common by the existence of the connecting portion 33, and the common electrode 35 is grounded by conducting at one place to this common region.
On the other hand, the individual electrodes 34 are formed on the upper surface of the support plate 30 so as to correspond to the individual electrodes 34.
7 by a method such as wire bonding, and is connected to a controller 6 (see FIG. 1) which is a voltage applying means via a driver IC (not shown). As a result, the controller 6 applies a voltage to each piezoelectric body 32 in accordance with an image signal. In addition, the piezoelectric body 32
Is polarized in the direction from the common electrode 35 to the individual electrode 34.

The pressure member 31 is, for example, an individual electrode 34 and a common electrode 35 on both surfaces of a PZT piezoelectric plate, respectively.
As the electrode layer to be the above, an Au / Ni film formed by plating or an Au / (Ni, Cr) film formed by sputtering is formed to a thickness of about 0.1 to 10 μm.
After being fixed to 0 by adhesion, it is formed by cutting with a dicing saw, for example. At least the insertion portion of the piezoelectric body 32 is divided from each other, but the connecting portion 33 is formed by reducing the cutting depth.

Next, the ink jetting operation of the ink jet head 12 having the above structure will be described. As shown in FIG. 3, the ink is supplied from the ink supply unit 7 (see FIG. 1) to the ink tube 28, and is filled in each ink chamber 23 via the ink supply port 22. When a positive pulsed voltage as shown in FIG. 5A is applied to the piezoelectric body 32 by the controller 6 which is a voltage applying means, an electric field is formed in the direction from the individual electrode 34 to the common electrode 35, The piezoelectric body 32 deforms and vibrates in a so-called longitudinal vibration mode.

Since the deformation of the piezoelectric body 32 to which the voltage is applied tends to be restrained in the region fixed to the support plate 30, as shown by the broken line in FIG. The extending insertion portion is sharply stretched and deformed, and the tip end surface is displaced in the direction of the nozzle hole 27. Due to this displacement, the ink filled in the ink chamber 23 is pressed so as to be pushed by the piston, whereby the ink flies in the form of liquid droplets from the nozzle holes 27 and adheres to the recording paper (not shown). Note that only one of the individual electrode 34 and the common electrode 35 may be formed in the fixed region of the piezoelectric body 32 with respect to the support plate 30 so that no deformation occurs in this region.

When the voltage application to the individual electrodes 34 is released and the electric field disappears, each piezoelectric body 32 returns to its original state. At this time, a negative pressure is generated inside the ink chamber 23, and the ink chamber 23 passes through the ink manifold 29 and the ink supply port 22.
Is replenished with ink and ready for the next ink ejection.

However, when the ink is replenished, as shown in FIG.
When the voltage is instantly set to zero and the piezoelectric body 32 is restored on the basis of the elasticity of the piezoelectric body 32 as shown in (3) to rapidly restore the insertion portion in the ink chamber 23, bubbles are sucked into the ink chamber 23 from the nozzle hole 27, When the next pulse voltage is applied, the bubbles may absorb the pressure and hinder the flight of the ink. Therefore, the nozzle hole 27 is formed in a tapered shape as described above, and as shown in FIG. 5B, the pulse shape of the voltage when the piezoelectric body 32 performs the restoring operation is inclined so that the piezoelectric body 32 has a slope. This is prevented by allowing the insertion part to return most quickly within the range where bubble suction does not occur.

Further, the diameter of the flying ink droplet can be changed by applying a pulse voltage having the same value but a different pulse width to that of FIG. 5 (a) and controlling the displacement amount of the insertion portion of each piezoelectric body 32. This makes it possible to change the diameter of dots adhering to the recording paper, which facilitates reproduction of halftones. For example, as shown in FIG. 5C, when the pulse width is reduced, the dot diameter is also reduced. The pulse voltage shown in FIG. 5 (d) is obtained by applying a rear pulse of a small voltage with a polarity opposite to that of the main pulse. By applying the pulse voltage of this waveform to each piezoelectric body 32, the ink column extending from the nozzle hole 27 can be forcibly drawn into the ink chamber 23 by the rear pulse after the ink droplet is ejected by the main pulse, so that the satellite noise is generated. Can be reduced. The pulse voltage shown in FIG. 5 (e) applies a small-voltage front pulse having the same polarity as the main pulse, and the pulse voltage of this waveform can suppress the voltage value of the main pulse to a low level. As a result, the driver's burden is reduced and the driver cost can be reduced.

By performing the ink jetting operation as described above independently for each ink chamber 23 according to the image signal, an image for one line is drawn and this is repeated in synchronization with the movement of the recording paper. As a result, an image corresponding to the image signal is drawn on the recording paper.

As described above, in this embodiment, the pressure member 31 having a cross section slightly smaller than the ink chamber 23.
The piezoelectric body 32 is inserted into the ink chamber 23 from the rear end side of the ink chamber 23 in the longitudinal direction, and based on the displacement of the insertion portion in the direction of the nozzle hole 27 formed in the front end side of the ink chamber 23 in the longitudinal direction. The ink filled in the ink chamber 23 is pressed by a piston so that the ink is ejected from the nozzle hole 27 in the same direction as the pressurizing direction of the ink. As a result, the required ink flight can be obtained with a small displacement of the inserted portion of the piezoelectric body 32, and the ink flight efficiency can be improved. As a result, the device can be driven at a low voltage, and the load on the driver IC is reduced. Therefore, an inexpensive low-voltage IC can be used, and the driver cost can be reduced.

Further, according to the structure of the present embodiment, the concave portion 21 for the ink chamber 32 and the piezoelectric body 32 of the pressing member 31 can be formed with a relatively high density by a dicing process or the like, and in addition, the ink can be formed. Since the area of the action surface at the time of pressurizing, that is, the area of the tip surface of the insertion portion of the piezoelectric body 32 can be small,
It is possible to increase the printing speed by increasing the number of high density nozzles. Further, in the present embodiment, it is not necessary to consider the resonance frequency of the thin film as in the case of pressurizing the ink through a thin film having a large working area that prevents the ink from directly contacting the piezoelectric body, and therefore high frequency response It is also excellent, which also makes it easy to achieve a high printing speed.

In addition, by forming each of the piezoelectric bodies 32 in a comb shape, the structural strength of each of the piezoelectric bodies 32 is increased, the durability and reliability of the device are improved, and the processing / assembly surface is handled. Since it is easy and the assembly variation is small and the accuracy is high, the yield is improved and the manufacturing cost can be reduced. In addition, since the common electrode 29 formed on the contact surface of the action member 26 of each piezoelectric body 27, 28 is made common by the existence of the connecting portion 33 and conducts, the common electrode 35 of each piezoelectric body 32 can be connected at one place. There is also an advantage that grounding is possible and connection can be easily performed.

By the way, in the above embodiment, FIG.
The pulse voltage shown in (e) was applied to displace the inserted portion of the piezoelectric body 32 as shown by the broken line in FIG.
5 (f) as well as reversing the polarization process for
Alternatively, even if a negative pulse voltage as shown in (g) is applied, the same displacement can be obtained in the insertion portion. The reason why the rising portion of the pulse in FIG. 5 (g) is inclined is the same as in the case of FIG. 5 (b).

Next, a modified example of the above embodiment will be described with reference to FIGS.
8 will be described with reference to FIG. 8, but members and functions and effects other than those described in particular are the same as those in the above-described embodiment, and thus the description thereof will be omitted.
Although the single-layer piezoelectric body 32 is used in the above embodiment, as shown in FIG. 6, the piezoelectric material is laminated into two or more n layers by a known green sheet method, and the individual electrode also serves as an adhesive layer inside. Multilayer piezoelectric body 40 in which 34 and common electrode 35 are formed
If you use, it is possible to obtain the same amount of displacement at a low voltage compared to the case of a single layer, and the generation force of the displacement becomes stronger, so it is possible to reduce the driver cost by low voltage driving and The flight stability of the droplet is improved. In FIG. 6, the broken line portion shows that no electrode is formed, and the region where both the individual electrode 34 and the common electrode 35 are formed corresponds to the insertion portion of the piezoelectric body 32.

Further, instead of the pressing member 31, as shown in FIG. 7, a portion corresponding to the insertion portion of the piezoelectric body 32 has the same shape as the insertion portion and is made of non-piezoelectric material such as ceramic. If the pressure member 43 formed of the material 41 and having the piezoelectric body 42 connected to the rear end portion of the non-piezoelectric material 41 located outside the ink chamber 23 is used, ink does not penetrate into the piezoelectric body 42 and the piezoelectric body The stability and durability of the piezoelectric body 42 are further improved as compared with the case where the insertion portion of the body 32 is overcoated. Further, the ink supply port 22
Of the ink supply port 2 to the ink chamber 23 side of the
Check valve 4 that closes 2 while opening when replenishing ink
By providing No. 4, backflow of the ink at the time of pressurization is prevented, thereby suppressing the pressure loss and further improving the ink flying efficiency.

In the above embodiment, the piezoelectric body 32 was overcoated to prevent ink permeation, but as shown in FIG. 8, the rear end opening of the ink chamber 23 is formed into a thin film partition wall 4.
The piezoelectric member 4 of the pressing member 46 is covered with 5 and sealed.
The partition wall 45 may be slightly pushed into the ink chamber 23 at the tip of 7. In this case, it is necessary to consider the response of the partition wall 45, but it is possible to completely prevent the ink from penetrating into the piezoelectric body 47.

Next, materials and the like that can be used for the ink jet head of the above embodiment will be described. Material of Piezoelectric Material As the material of the piezoelectric materials 32, 40, 42, 47, the following piezoelectric materials can be used. (1) Piezoelectric crystal Quartz (SiO ₂ ), Rochelle salt (RS: NaKC ₄ H
₄ O ₆・ 4H ₂ O) Ethylenediamine tartrate (ETD: C ₆ H ₁₄ N ₂ O ₆ )
, Potassium tartrate (DKT: K ₂ C ₄ H ₄ O ₆ 1 / 2H
₂ O), diammonium phosphate (ADP: NH ₄ H ₂
PO ₄ ), perovskite crystals (ex. CaTi
O ₃ , BaTiO ₃ , PLZT), tungsten bronze-based crystal (ex. Na _x WO ₃ [0.1 <x <0.2
8]), sodium barium niobate (Ba ₂ NaN
b ₅ O ₁₅ ), potassium lead niobate (Pb ₂ KNb
₅ O ₁₅ ), lithium niobate (LiNbO ₃ ), lithium tantalate (LiTaO ₃ ), sodium chlorate (NaClO ₃ ), tourmaline (Tourmalin)
e), zinc blende (ZuS), lithium sulfate (LiS)
O ₄ H ₂ O), lithium metagallate (LiGa
O ₂ ), lithium iodate (LiIO ₃ ), glycine sulfate (TGS), bismuth germanate (Bi ₁₂ G)
eO ₂₀ ), lithium germanate (LiGeO ₃ )
, Barium titanate, germanium (Ba ₂ G
Crystals such as e ₂ TiO ₃ ).

(2) Piezoelectric semiconductor Wurtzite, BeO, ZnO, CdS, CdSe
, AlN. (3) Piezoelectric ceramics Barium titanate (BaTiO ₃ ), lead zirconate titanate (PbTiO ₃ · PbZrO ₃ ),
Titanium lead (PbTiO _3), niobate barium lead _{((Ba-Pb) Nb 2} O 6). (4) The above (1) piezoelectric crystal, (2) piezoelectric semiconductor,
(3) The powder of the piezoelectric ceramic material may be dispersed and molded in plastics. (5) piezoelectric polymer polyvinylidene fluoride _{PVDF (-CH 2 -CF 2 -)} n
, Polyvinylidene fluoride / PZT, rubber / PZT
, Copolymer of trifluoroethylene and vinylidene fluoride, copolymer of vinylidene cyanide and vinyl acetate,
Polyvinylidene, etc. The above-mentioned piezoelectric materials may be polarized and then processed as a piezoelectric body, or may be processed as a piezoelectric body and then polarized.
Further, they may be laminated as needed so that they can be driven at a low voltage.

Overcoat Treatment of Piezoelectric Body The overcoat treatment of the piezoelectric body 32 is performed in the following (1) to
The method described in (5) can also be used. (1) Application of plastics Saturated polyester resin, polyamide resin, polyimide resin, acrylic resin, aramid resin, ethylene-vinyl acetate resin, ion-crosslinked olefin copolymer (ionomer), styrene-butadiene block copolymer, polyacetal, Thermoplastic resins such as polycarbonate, vinyl chloride-vinyl acetate copolymer, cellulose ester, polyimide and styrene resin.

Thermosetting resins such as epoxy resin, phenoxy resin, urethane resin, nylons, silicone resin, fluorosilicone resin, phenol resin, melamine resin, xylene resin, alkyd resin, and thermosetting acrylic resin. Polyvinyl carpazole,
Photoconductive resins such as polyvinyl pyrene, polyvinyl anthracene, and polyvinylol.

These can be used alone or in combination. In addition, engineering plastics such as liquid crystal polymer, a mixture of plastics and powder, and whiskers may be used. Photosensitive resin, thick film photoresist resin, etc. can be used. Bakelite, fluorocarbon resin, glass / epoxy resin (glass filler mixed in epoxy) may be used. These are coating, dipping,
A known liquid application method such as a spray method may be used. Among the above, in particular, polyimide resin, aramid resin, epoxy resin, phenoxy resin, fluorosilicone resin,
The effect of fluororesin and glass / epoxy resin is excellent.

(2) Vapor Deposition of Oxidizing / Nitriding / Sulfide Metal Compounds Metal oxide compounds (SiO ₂ , SiO, CrO, Al ₂ O ₃
Etc.), metal nitride compounds (Si ₃ N ₄ , AlN, etc.), metal sulfide compounds (ZnS, etc.), or alloys thereof,
It is coated by vacuum deposition or sputtering. In addition, the above (1)
The above plastic may be applied by vapor deposition or parylene resin vapor deposition. Among the above, Al ₂ O ₃ , S
The effect of i ₃ N ₄ and parylene resin is excellent.

(3) Application of hydrocarbon compounds Hydrocarbons, oxygen-containing hydrocarbons, sulfur-containing hydrocarbons and other group IV element-containing hydrocarbons, nitrogen-containing hydrocarbons, silicon-containing hydrocarbons, fluorine-containing hydrocarbons, etc. Halogen-containing hydrocarbons, Group III element-containing hydrocarbons
-Apply by CVD (plasma CVD) and perform overcoat treatment. Alternatively, under these mixed gas phases, P-C
It may be applied by VD. Among the above, the effect of the fluorine-containing hydrocarbon is excellent. Note that these films need to be appropriately provided with an undercoat of a-Si (amorphous silicon), a-SiC, a-SiN, or the like according to the compatibility of the adhesiveness with the piezoelectric body. (4) Instead of coating the surface of the piezoelectric plate in the coating liquid state with the plastics of (1) above, the piezoelectric body forming portion is replaced and impregnated under reduced pressure for molding. (5) The surface of the piezoelectric plate is surface-treated with an ink repellent solvent.

When the overcoat films formed by the above methods (1) to (5) are compared with each other, the following characteristics are observed (however, (3) has an undercoat). Strength: Strong (2), (3)> (1), (4)> (5) Weak smoothness: Good (1), (4)> (2), (3), (5) Poor adhesion ( Vibration resistance included: Strong (1), (4)> (2), (3)> (5) Weak durability (including ink resistance): Good (1), (4)> (2) , (3)> (5) Bad Others, the processing of (5) is simple and can be used as the post-processing of (1) to (4). In terms of cost, (1) and (4) are particularly inexpensive. The methods (1) to (5) described above may be appropriately combined and used depending on the piezoelectric body and the ink type.

Materials for Top Plate, Substrate, and Non-Piezoelectric Material Materials that can be used for the top plate 20, the substrates 24, 25, and the non-piezoelectric material 41 include the following (1) to (4). (1) Ceramics Al ₂ O ₃ , SiC, C, BaTiO ₃ , BiO ₃
.3SnO ₂ , Pb (Zr _x , Ti _1-x ) O ₃ , ZnO
, SiO ₂ , (1-x) Pb (Zr _x , Ti _1-x ) O ₃
+ (X) La ₂ O ₃ , Zn _1-x Mn _x Fe ₂ O ₃ , γ-F
e ₂ O ₃ , Sr · 6Fe ₂ O ₃ , La _1-x Ca _x CrO ₃
, SnO ₂ , transition metal oxides, ZnO-Bi ₂ O ₃
, Semiconductor BaTiO ₃ , β-Al ₂ O ₃ , stabilized zirconia, LaB ₆ , B ₄ C, diamond, Ti
N, TiC, Si ₃ N ₄ , Y ₂ O ₂ S: Eu, PL
_{ZT, ThO 2, -CaO · nSiO} 2, Ca
₅ (F, Cl) P ₃ O ₁₂ , TiO ₂ , K ₂ O.nAl ₂
O ₃ .

(2) Glasses Elemental glass = Si, Se, Te, As Hydrogen-bonded glass = HPO ₃ , H ₃ PO ₄ , SiO ₂ ,
_{B 2 O 2, P 2 O} 5, GeO 2, As 2 O 3 oxide glass _{= SbO 3, Bi 2 O 3} , P 2 O 3, V 2
O ₅ , Sb ₂ O ₅ , As ₂ O ₃ , So ₃ , ZrO ₂ Fluoride glass = BeF ₂ , Chloride glass = ZnCl ₂ Sulfide glass = GeS ₂ , As ₂ S ₃ Carbonate glass = K ₂ CO ₃ , MgCO ₃ nitrate glass = NaNO ₃ , KNO ₃ , AgNO ₃ sulfate glass = Na ₂ S ₂ O ₃ , H ₂ O, Tl ₂ SO
_4, alum silicate glass = SiO ₂ silicate alkali glass _{= Na 2 O-CaO-SiO} 2 potash lime glass _{= K 2 O-CaO-SiO} 2 soda _{= Na 2 O-CaO-SiO} 2 lead glass, barium glass Borosilicate glass.

(3) Plastics Saturated polyester resin, polyamide resin, polyimide resin, aramid resin, acrylic resin, ethylene-vinyl acetate resin, ion-crosslinked olefin copolymer (ionomer), styrene-butadiene block copolymer, polyacetal Thermoplastic resins such as polyphenylene sulfide, polycarbonate, vinyl chloride-vinyl acetate copolymer, cellulose ester, polyimide, polysulfone, and styrene resin. Thermosetting resins such as epoxy resin, phenoxy resin, urethane resin, nylon resin, silicone resin, phenol resin, melamine resin, xylene resin, alkyd resin, thermosetting acrylic resin. Polyvinylcarbazole, polyvinylpyrene, polyvinylanthracene,
Photoconductive resin such as polyvinyl chloride.

The above items (1) to (3) can be used alone or in combination. In addition, engineered plastics such as liquid crystal polymer, a mixture of plastics and powder, whiskers, glass filler and the like may be used. Photosensitive resin, thick film photoresist resin, etc. can also be used. Bakelite, fluorine resin,
Glass / epoxy resin (glass filler mixed in epoxy) may be used.

(4) Others In addition to rubber and synthetic rubber, all metals can be used when the side surface in contact with the ink chamber is coated with an insulating film.
In addition, regarding the top plate 20, the materials listed in (1) to (4) above are processed from the beginning by using plate-shaped and then groove-forming or die-molding, pattern etching, photocuring, or the like. It may be molded into the shape of the plate 20.

Adhesive Material As the adhesive used for assembling the ink jet head, the following adhesives (1) to (4) can be used. However, when the adhesive layer is used as a conductor when the common electrode is grounded, it naturally needs to have conductivity. (1) Thermosetting resin adhesives such as epoxy resin, phenol resin, phenoxy resin, acrylic resin, furan resin, polyurethane resin, polyimide resin, silicone resin. (2) Thermoplastic resin adhesives such as polyvinyl acetate, polyvinyl chloride, vinyl acetal, polyvinyl alcohol, and polyvinyl butyral. (3) UV curable resin adhesive. (4) Anaerobic curable adhesive.

Material of Sealing Material As the material of the sealing material 36, in addition to rubbers such as fluorosilicone rubber, the above adhesive can be used.

Materials of Partition Wall As the material of the partition wall 45, the following materials can be used. (1) Thermosetting resins such as epoxy resin, phenoxy resin, urethane resin, nylons, silicone resin, fluorosilicone resin, phenol resin, melamine resin, xylene resin, alkyd resin, and thermosetting acrylic resin. Among the above, epoxy resin, phenoxy resin and fluorosilicone resin are preferably used.

(2) Polyester resin, polyamide resin, acrylic resin, aramid resin, ethylene-
Thermoplastics of vinyl acetate resin, ion-crosslinked olefin copolymer (ionomer), styrene-butadiene block copolymer, polyacetal, polyphenylene sulfide, polycarbonate, vinyl chloride-vinyl acetate copolymer, cellulose ester, polyimide, styrene resin, etc. resin. Among the above, aramid resin, polyimide resin, polyamide resin, and ethylene-vinyl acetate resin are preferably used.

(3) Liquid crystal polymer (4) Photosensitive resin, thick film photoresist resin (5) Rubber, synthetic rubber (6) Thin plate of nickel, stainless steel, titanium, tungsten, etc. In addition, the above (1) to (5) The materials listed in () may be used alone or in combination.

Comparing the superiority and inferiority of the materials mentioned in (1) to (6) above, although it is almost the same in (1) to (3), excellent (1) to (3)>(4)>(6)> (5) Inferiority can be seen. Furthermore, the material thickness is 100μ
It is preferably m or less, and preferably 50 μm or less.

[0054]

As is apparent from the above description, in the ink jet recording apparatus of the present invention, the ink filled in the ink chamber is pressed by the pressure member so as to be pushed by the piston, and the pressure is applied in the same direction as the pressure direction. Since the ink droplets are ejected, it is possible to achieve efficient and stable ink ejection with a small displacement of the pressure member, and as a result, it is possible to drive the device at a low voltage and reduce the driver cost. You can

Further, according to the structure of the present invention, since the ink chambers and the pressure members corresponding thereto can be formed with a high density relatively easily, a high density and a large number of nozzles enables a high printing speed. Can be realized.

According to the ink jet recording apparatus of the present invention in which the piezoelectric body of the pressing member is formed in a comb shape, the structural strength of each piezoelectric body is increased, the durability and reliability of the apparatus are improved, and Since the handling of the processing / assembly surface is easy, the assembly variation is small and the accuracy is high, the yield is improved and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an inkjet recording apparatus.

FIG. 2 is a widthwise sectional view of an inkjet head.

3 is a longitudinal sectional view of the inkjet head shown in FIG.

FIG. 4 is a perspective view of a pressing member formed in a so-called comb shape.

FIG. 5 is a diagram showing a pulse shape of a voltage applied to the piezoelectric body of the pressing member.

FIG. 6 is a side view showing a laminated piezoelectric body used as a pressing member.

FIG. 7 is a diagram showing a modified example in which an insertion portion of a pressure member is formed of a non-piezoelectric material and a modified example in which a check valve is provided at an ink supply port.

FIG. 8 is a diagram showing a modified example in which a pressure member pressurizes an ink chamber via a partition wall.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ink jet recording device, 6 ... Controller (voltage application means), 20 ... Top plate (non-piezoelectric member), 21 ... Recessed part,
23 ... Ink chamber, 24 ... Substrate (non-piezoelectric member), 25 ... Second substrate, 26 ... Nozzle plate, 27 ... Nozzle hole (nozzle portion), 31, 43 ... Pressurizing member, 32, 42 ... Piezoelectric body, 41 ... Non-piezoelectric member.

Claims (2)

[Claims] 1. A plurality of ink chambers which are formed by being surrounded by a non-piezoelectric member, each of which is elongated and elongated, and a plurality of nozzle portions which are provided on one end side in the longitudinal direction of the ink chambers and correspond to the respective ink chambers. At least a part is inserted into each ink chamber from the other end side in the longitudinal direction of the ink chamber, and the inserted portion is formed of a piezoelectric body or a non-piezoelectric material connected to the piezoelectric body, and from the cross section of the ink chamber. A pressure member having a slightly smaller cross section, and voltage applying means for applying a voltage to the piezoelectric body of the pressure member according to an image signal. The voltage applying means applies a voltage to the piezoelectric body. By applying and deforming the ink, the insertion portion of the pressure member is displaced in the direction of the nozzle portion based on this deformation, so that the ink filled in the ink chamber is ejected from the nozzle portion. Recording device. 2. The ink jet recording apparatus according to claim 1, wherein the piezoelectric body of the pressing member is connected to each other at a portion other than the portion corresponding to the ink chamber and is formed in a comb tooth shape.