JP2003094632A - Ink jet head, its manufacturing method and ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an ink supply channel to supply ink, though the channel is reduced in its cross sectional area due to the higher density of an actuator and its resultant increase in a flow resistance in a ink jet head. SOLUTION: The ink jet head has a diaphragm 64 constituting ink liquid chambers 62 and a part of an ink supply channel 91, and an electrode substrate 70 wherein individual electrodes 74 for ink ejection and individual electrodes 94 for ink supply are arranged in opposite to each other relative to the diaphragm 64 via a gap. An ink conveyer unit is formed of the diaphragm 64 constituting a part of the ink supply channel 91, and the individual electrodes 74 for the ink ejection or the like. A drive signal is applied to the individual electrodes 74 for the ink ejection, the diaphragm 64 of the ink supply channel 91 is deformed by an electrostatic force to such ink (convey) from a common ink flow channel 76, and then the drive signal is applied to the individual electrodes 74 for the ink ejection to eject ink from the nozzles 51.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic ink jet head used in a printer, a copying machine, a facsimile machine, etc., a method of manufacturing the same, and an ink jet recording apparatus. The present invention relates to an electrostatic ink jet head that can reduce fluid resistance even when it becomes small and can stably supply ink, a manufacturing method thereof, and an ink jet recording apparatus.

[0002]

2. Description of the Related Art There is no ink jet head having an ink transport unit driven by electrostatic force. The invention (first conventional example) described in Japanese Patent Application Laid-Open No. 11-993 (inkjet head, method for manufacturing the same, and inkjet recording apparatus) relates to the regulation of the partition wall height of the cavity. 16
It is specified in the range of 0 μm. The upper limit of the partition wall height is determined from the viewpoint of suppressing crosstalk and improving productivity,
The lower limit is determined by the ink supply capacity. That is, by defining the height of the partition wall, it is avoided that the fluid resistance increases and the ink does not flow easily when the wall is low.

The invention (second conventional example) described in Japanese Patent Application Laid-Open No. 2000-141648 (ink jet head) relates to an ink supply passage, and a common ink passage is provided on the upper surface of the pressurized liquid chamber, To provide an ink supply path communicating with all the pressurized liquid chambers to provide an inkjet head with high nozzle density.

Further, an ink jet head having a back surface flow path and a back surface electrode for finishing a head having a matrix of nozzles is also known (third conventional example). The ink supply of this ink jet head has a structure in which a canal flow path connecting a common ink flow path is arranged and branched to supply ink to each pressurized liquid chamber, thereby providing an ink jet head having a high nozzle density.

[0005]

In the above-mentioned first conventional example, the partition wall height of the liquid chamber is defined in the range of 100 to 160 μm, and this lower limit value is defined from the viewpoint of the ink supply capacity. By defining the height of the partition wall, it is avoided that the fluid resistance increases and the ink does not easily flow when the partition wall height is low. However, as the density of nozzles further increases in the future, it is required that the height of partition walls be 100 μm or less.

In the second conventional example, the common ink flow path is provided on the upper surface of the pressurized liquid chamber, and the ink supply path is provided to communicate with all the pressurized liquid chambers from the common ink flow path at the same time. Since the road is composed of a special layer structure, the manufacturing process is complicated and expensive.

Further, in the third conventional example, an ink jet head having high density matrix nozzles is provided, and although there is a description that a canal flow path connecting ink flow paths is provided therein, there is a problem with ink. Considering the case where the cross-sectional area of the supply path becomes smaller and the fluid resistance becomes too large, it is expected that the ink will not flow easily.

A first object of the present invention is to cope with the difficulty of ink supply because the cross-sectional area of the ink supply path becomes small and the fluid resistance becomes large as the density of the actuator forming the ink jet head becomes higher. However, with the structure of the ink supply path equipped with the ink transport unit,
This is to enable stable ink supply even in a supply path having a small cross-sectional area.

A second object of the present invention is to stably supply an ink amount commensurate with the ink amount required in the ink pressurizing chamber by driving the ink transport unit at a predetermined driving timing. .

A third object of the present invention is to enable stable ink supply even when the distance between the ink pressurizing liquid chamber and the common ink flow path is large and the flow path resistance is large, and the ink jet is used. It is to increase the degree of freedom in designing the head.

A fourth object of the present invention is to simultaneously realize a process of forming an ink pressurizing liquid chamber of an electrostatic ink jet head and a process of forming an ink supply path having an ink transporting means of the present invention, thereby achieving high density. It is to provide a nozzle head. Moreover, it is providing the manufacturing method.

[0012]

The present invention has been made to achieve the above object, and the invention of claim 1 includes a plurality of nozzles and a pressurized liquid chamber communicating with each nozzle. In an inkjet head having a common ink flow path for supplying ink to each pressurized liquid chamber via an ink supply path, a vibration plate forming a part of the ink supply path, and a gap with respect to the vibration plate It is characterized in that it has an electrode substrate on which the individual electrodes for ink supply are arranged to face each other, and the ink is transported by deforming the vibrating plate by electrostatic force.

According to a second aspect of the present invention, there are provided a plurality of nozzles, each pressurizing liquid chamber communicating with each nozzle, and a common ink flow passage for supplying ink to each pressurizing liquid chamber via an ink supply passage. In the inkjet head, a vibrating plate forming a part of the pressurized liquid chamber and the ink supply path, and an ink ejecting individual electrode and an ink supplying individual electrode are arranged to face the vibrating plate via a gap. In addition, the vibrating plate is deformed by an electrostatic force to transport the ink and eject the ink.

According to a third aspect of the invention, in the ink jet head according to the second aspect of the invention, the drive waveform of each ink supply individual electrode is a drive waveform synchronized with the drive waveform of each ink ejection individual electrode. Characterize.

According to a fourth aspect of the present invention, in the ink jet head according to the first or second aspect of the invention, the inlet portion and the outlet portion of the ink supply passage each have a directional fluid resistance.

According to a fifth aspect of the invention, in the ink jet head according to the first or second aspect of the invention, the ink supply path has a plurality of sets of the vibration plate and the ink supply individual electrodes, and each part of the vibration plate is provided. The feature is that ink is transported in conjunction with each other.

According to a sixth aspect of the invention, in the ink jet head according to the fifth aspect of the invention, the ink supply passage is provided with a fluid resistance projecting toward the opposite side of the diaphragm in the flow passage. .

According to a seventh aspect of the present invention, in the method of manufacturing an ink jet head according to the first to sixth aspects, the pressurizing liquid chamber and the ink supply passage are formed in the same step, and the ink discharge individual electrode is formed. And the individual electrode for ink supply is formed in the same process.

An eighth aspect of the invention is an ink jet recording apparatus using the ink jet head according to the first to sixth aspects of the invention.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
This will be described with reference to FIGS. FIG. 1A is a perspective view showing an outline of an inkjet recording apparatus using an inkjet head according to the present invention, and FIG. 1B is a side sectional view of the same. This ink jet recording apparatus includes a recording apparatus main body 1
A print mechanism unit 2 including a carriage 13 movable in the main scanning direction, an inkjet head 14 mounted on the carriage, an ink cartridge 15 for supplying ink to the inkjet head 14, and the like is housed inside the printer main body 1 A paper feed cassette (or a paper feed tray) 4 capable of stacking a large number of papers 3 from the front side can be detachably attached to the unit, and the papers 3 can be manually fed. The manual feed tray 5 can be opened and closed, the paper 3 fed from the paper feed cassette 4 or the manual feed tray 5 is taken in, the desired image is recorded by the printing mechanism unit 2, and then the paper ejected mounted on the rear surface side. The paper is discharged to the tray 6.

The printing mechanism 2 is slidable in the main scanning direction (the direction perpendicular to the paper surface in FIG. 1B) of the carriage 13 by the main guide rod 11 and the sub guide rods 12 which are horizontally mounted on the left and right side plates (not shown). The carriage 13 is provided with a plurality of recording heads each including a recording head including an inkjet head 14 that discharges ink droplets of yellow (Y), cyan (C), magenta (M), and black (Bk). They are arranged in a direction intersecting with the main scanning direction, and are mounted with the ink droplet ejection direction facing downward. In addition, the carriage 13 has
Each ink cartridge 15 for supplying each color ink is attached to each inkjet head 14 in a replaceable manner.

The ink cartridge 15 has an atmosphere port communicating with the atmosphere above, a supply port supplying ink to the ink jet head 14 below, and a porous body filled with ink inside, which is porous. The ink supplied to the inkjet head is maintained at a slight negative pressure by the capillary force of the body.

Although the ink jet heads 14 for the respective colors are used here as the recording head, a single head having nozzles for ejecting ink droplets for the respective colors may be used. Furthermore, an inkjet head 1 used as a recording head
Reference numeral 4 denotes a piezo type that presses ink through a diaphragm that forms a wall surface of a liquid chamber by an electromechanical conversion element such as a piezoelectric element, or a bubble type that presses ink by generating bubbles by a heating resistor, or an ink flow. It is possible to use an electrostatic type or the like, which displaces the diaphragm by the electrostatic force between the diaphragm forming the wall surface of the road and the electrode facing the diaphragm to press the ink.
In this embodiment, an electrostatic inkjet head is used.

Here, the carriage 13 is slidably fitted to the main guide rod 11 on the rear side (downstream side in the sheet conveying direction), and the front side (downstream side on the sheet conveying direction) in the sub guide rod 1.
2 is slidably mounted. Then, since the carriage 13 is moved and scanned in the main scanning direction, the main scanning motor 1
A timing belt 20 is stretched between a drive pulley 18 and a driven pulley 19 which are rotatably driven by 7, and the timing belt 20 is fixed to the carriage 13. It is driven back and forth.

On the other hand, the paper 3 set in the paper feed cassette 4
For feeding the paper 3 to the lower side of the recording head, a paper feed roller 21 and a friction pad 22 for separating and feeding the paper 3 from the paper feed cassette 4, and a guide member 23 for guiding the paper 3.
A transport roller 24 that reverses and transports the fed paper 3, a transport roller 25 that is pressed against the peripheral surface of the transport roller 24, and a tip roller 26 that defines the feed angle of the paper 3 from the transport roller 24. Is provided. The transport roller 24 is rotationally driven by the sub-scanning motor 27 via a gear train.

Further, there is provided a print receiving member 29 which is a paper guide member for guiding the paper 3 delivered from the carrying roller 24 below the recording head in correspondence with the movement range of the carriage 13 in the main scanning direction. . This copy receiving member 2
A transport roller 31 and a spur 32 that are driven to rotate in order to send out the paper 3 in the paper discharge direction are provided on the downstream side of the paper transport direction of 9, and further a paper discharge roller 33 and a spur 34 that send the paper 3 to the paper discharge tray 6. And a guide member 3 that forms a paper discharge path
5, 36 are provided.

At the time of recording, by driving the ink jet head 14 of the recording head in accordance with the image signal while moving the carriage 13, ink is ejected to the stopped paper 3 to record one line, and the paper 3 After carrying a predetermined amount, the next line is recorded. Upon receiving a recording end signal or a signal that the trailing edge of the sheet 3 has reached the recording area, the recording operation is terminated and the sheet 3 is ejected.

Further, a recovery device 37 for recovering the ejection failure of the head 14 is arranged at a position outside the recording area on the right end side of the carriage 13 in the moving direction. Recovery device 3
Reference numeral 7 has a cap means, a suction means, and a cleaning means. The carriage 13 is moved to the recovery device 37 side during printing standby, the head 14 is capped by the capping means, and the ejection port portion is kept wet to prevent ejection failure due to ink drying. Also, by ejecting ink that is not related to recording during recording,
The ink viscosity of all ejection ports is made constant, and stable ejection performance is maintained.

When ejection failure occurs, the ejection port of the head 14 is sealed by a capping unit, and bubbles and the like are sucked out from the ejection port by a suction unit together with ink through a tube, and ink and dust adhered to the ejection port surface. Is removed by the cleaning means and the ejection failure is recovered. Further, the sucked ink is discharged to the waste ink reservoir installed in the lower part of the main body and absorbed and held by the ink absorber inside the waste ink reservoir.

FIG. 2 shows the structure of a general conventional electrostatic ink jet head, and FIG. 2 (A) is a partially cutaway perspective view showing the appearance of the electrostatic ink jet head.
2B is a sectional view taken along line AA of FIG. The conventional electrostatic ink jet head includes a nozzle substrate 110, a diaphragm substrate 120, and an electrode substrate 130.
The nozzle substrate 110 has nozzles 111 for ejecting ink,
A fluid resistance 112 is formed. A diaphragm 123 is provided on the diaphragm substrate 120, and a common liquid chamber 121 and a pressurized liquid chamber 12 are provided.
2 is formed, the common liquid chamber 121 communicates with the back flow passage 131, and the bottom of the pressurized liquid chamber 122 is formed by the vibrating plate 124. A vibrating chamber 132 is formed in the electrode substrate 130, and an individual electrode 133 is formed at the bottom of the vibrating chamber 132 so as to face the vibrating plate 124. The outside of the individual electrode 133 is FP.
It is an electrode pad 134 for connecting to C or the like.
The characteristic is as follows. (1) Ink flows from the common liquid chamber 121 into each pressurized liquid chamber 122 through the fluid resistance 112. Actually individual electrode 1
The longitudinal direction of 33 is about 1 mm, and the fluid resistance and the ink flow path are about 0.2 to 0.3 mm. (2) The fluid resistance 112 is dug on the nozzle substrate side at an interval of about 0.02 mm. (3) The nozzle rows are two rows and arranged in a staggered arrangement. (4) The electrode pads 134 are taken out from both ends of the upper surface of the head.

According to the present invention, in the electrostatic ink jet head, the ink transport unit is installed in the ink supply path between the common liquid chamber and the individual pressurized liquid chambers, and the cross-sectional area of the ink supply path is reduced. Enables stable and stable ink supply.
In particular, in an ink jet head having a matrix-shaped nozzle for increasing the density, the ink supply is often not uniform due to different distances to the pressurized liquid chambers, so that the present invention works effectively.

(Embodiment 1) FIG. 3 is an exploded perspective view of an electrostatic ink jet head according to Embodiment 1 of the present invention.
The invention corresponds to claims 1 and 2. 4 to 6 are views showing the outline of the process flow for manufacturing the electrostatic ink jet head according to the embodiment of the present invention. First, Example 1
The main part of the electrostatic ink jet head will be described with reference to FIGS. In the embodiments of the present invention, an electrostatic actuator is described as an example, but actuators of other methods may be applied to the present invention. In that case, the ink ejection mechanism of the pressurized liquid chamber uses a piezoelectric element or a heating element. In the electrostatic ink jet head of the first embodiment, the vibrating plate substrate 60 on which the electrode substrate 70 serving as a supporting substrate, the silicon oxide film 71, the ink ejecting individual electrode 74, the ink supplying individual electrode 94, and the vibrating plate 64 are formed. , The nozzle substrate 50 and the like. Vibration chambers 73 and 93 are formed between the vibration plate 64 and the individual electrodes 74 and 94 (more precisely, between the protection films 75 and 95). The vibrating plate 64 and the individual electrode 9 for ink supply through the minute gap.
When a drive signal is applied at a predetermined timing between 4 and 4, the vibrating plate 64 of the portion corresponding to the ink supply individual electrode 94 is displaced toward the individual electrode (counter electrode) side by electrostatic force, and then the voltage is returned to 0. Due to the elastic force of the vibrating plate 64 that is displaced to the original position, the ink is moved from the ink supply path 91 to the ink liquid chamber 6 via the fluid resistance 65 by the force of returning to the original position.
Transport to 2. Next, a drive signal is applied to the individual ink ejection electrodes 74 at a predetermined timing, and the corresponding portion of the vibrating plate 64 is similarly vibrated to eject the ink in the ink liquid chamber 62 from the nozzles 51.

Individual electrodes 7 for ink ejection and ink supply
The protective films 75 and 95 on 4, 94 prevent short-circuiting between the diaphragm 64 and the individual electrodes 74 and 94, and an insulating film having the same function may be formed on the diaphragm side. Further, it can be omitted when the diaphragm is operated by a driving method in which the individual electrodes are not in contact with each other. Further, the gap shape of this embodiment is merely an example, and other gap shapes can be used depending on the purpose. In order to achieve the desired ink ejection force, the optimum design is performed for parameters such as the related gap length, diaphragm thickness, diaphragm material, diaphragm short side length, fluid resistance, and protective film thickness / material. There is a need.

In the present invention, the ink transport unit is formed in the ink supply path, which is composed of the vibration plate driven by electrostatic force, the pressurized liquid chamber, the fluid resistance, the individual electrode, the gap and the like. A drive signal is applied to the individual electrodes for ink supply of this ink transport unit, the diaphragm is deflected by electrostatic force to draw in ink, and when the drive voltage is 0 V, the restoring force of the diaphragm causes the desired ink amount to reach the next liquid chamber. Transport to. The place where the ink transport unit is arranged is determined in accordance with its capacity design (ink discharge amount by the diaphragm, directionality of fluid resistance at both ends in the case of a liquid chamber shape, etc.).

In the ink jet head of Example 1, 3
A nozzle substrate is formed by laying out the nozzles arranged in a matrix of rows or more on one flat plate. After adhering the nozzle substrate, the vibration plate substrate and the supporting substrate, they are cut out into a head size, and an FPC is pressure-bonded to the back surface side to enable external connection, thereby completing the inkjet head.

A method of manufacturing the ink jet head of the first embodiment will be described based on the process flows shown in FIGS. The boron used as the electrode substrate 70 is 0.01 to 0.
A silicon oxide film is grown to a thickness of 2 μm by the thermal oxidation wet method on the entire <100> silicon wafer containing 1 Ωcm (FIG. 4A).

Then, a resist pattern corresponding to a desired electrode pattern forming area of the ink jetting liquid chamber and the ink supply path is formed. Next, wet etching is performed using an etchant (hydrofluoric acid) of the silicon oxide film 71, and the resist is removed after etching. A silicate glass containing a second impurity (for example, phosphorus) is mixed with a solvent, coated on a supporting substrate, prebaked, and diffused in a diffusion furnace. Here, the second impurity may be introduced into a similar selected area by solid diffusion, high energy ion implantation or the like. The diffusion condition is as long as 1200 ° C. for 100 hours.
In this regard, the method of the embodiment described later can be used (FIG. 4 (B)).

The silicate glass containing impurities and the silicon oxide film 71 are entirely removed with a chemical solution (mixed acid nitric acid, hydrofluoric acid) (FIG. 4C). After that, the supporting substrate is set to about 650 nm.
Oxidation is performed to pattern the gap spacer area (FIG. 4D).

Deposition of individual electrode materials (TiN etc.)
Is performed by a sputtering device to pattern the individual electrodes 74 and 94 for ink ejection and ink supply corresponding to the ink liquid chamber 62 and the ink supply passage 91. (FIG. 4 (E)) Here, when both the individual electrodes 74 and 94 are the silicon supporting substrate itself containing impurities, the electrode material such as TiN does not have to be deposited. Next, the insulating films 75 and 95 are deposited and patterned so as to protect both the individual electrodes 74 and 94 (FIG. 4F). Here, when TiN is not deposited, the silicon supporting substrate can be thermally oxidized and used as a protective film.

The wafer on the diaphragm side is attached by direct bonding or the like (FIG. 5 (G)). Deposit the silicon nitride film 81,
The portion that becomes the ink liquid chamber 62, the ink supply passage 91 and the common liquid chamber, and the portion that becomes the common ink flow passage 76 are photoengraved and etched. After removing the resist, silicon is etched by KOH (the thickness of the vibrating plate is left to be 1 to 3 μm) to form a portion which becomes the ink liquid chamber 62 and a portion which becomes the common ink flow path 76 (FIG. 5 (H)). The flow path from the ink supply path 91 to each ink liquid chamber 62 may be formed on the nozzle plate side so as to include fluid resistance.

After removing the silicon nitride film 81, TiN or the like is deposited and the pad is patterned to form the back electrode pad 82 (FIG. 5 (I)). Next, the separately processed nozzle substrate 50 is attached with an adhesive and cured (FIG. 5 (J)).

A gold bump 83, for example, is formed on the back electrode pad 82.
Or the gold bumps 83 are attached to the FPC 80 side. Alternatively, at the time of FPC bonding, ACF may be sandwiched between them to be pressure-bonded to have conductivity (FIG. 6 (K)). The FPC 80 is adhered to the supporting substrate, and the bumps 83 are simultaneously pressed (FIG. 6).
(L)).

(Embodiment 2) FIG. 7 is a diagram showing an electrostatic ink jet head of Embodiment 2 and its drive circuit, and corresponds to claim 3. The operation of the inkjet head of Example 2 manufactured in the same manner as the process flow of the inkjet head of Example 1 will be described. The electrostatic ink jet head of the second embodiment has two ink transport units for one ink liquid chamber 62. That is, the first and second ink supply paths 91a and 91b are formed between the common ink flow path 76 and the ink liquid chamber 62, and the first and second ink supply paths 91a and 91b are also formed.
First and second individual ink supply electrodes 94a and 94b are formed on the electrode substrate corresponding to the second ink supply paths 91a and 91b, and the first and second ink supply paths 91a and 91b are formed.
The vibrating plate 64 corresponding to the part is driven by electrostatic force.

When the ink is ejected from the specific nozzle 51 in the electrostatic ink jet head having the above-mentioned configuration, it is necessary to replenish the ink liquid chamber 62 with the ejection amount. When viewed from the ink liquid chamber side, ink easily enters from the ink supply passages 91a and 91b side (fluid resistance is small) at the timing when the vibrating plate 64 bends, and ink does not easily return to the ink flow passage side at ejection timing (fluid resistance). Is required for the injection characteristics. for that purpose,
It is preferable to raise the ink transport waveform in the preceding stage before the rise of the ink discharge waveform, and to lower the ink transport waveform during ejection.

FIG. 8 is a timing chart showing an example of drive waveforms for driving the ink supply individual electrodes of the ink transport unit. As shown in FIG. 8, the driver IC 96
Are the second electrode transport unit, the first ink transport unit, and the ink liquid chamber in that order, respectively.
A drive pulse is applied to a and 74, and a drive signal synchronized with the timing of the ink ejection drive waveform is output so that the corresponding diaphragm is driven. In this way, the front stage of the ink liquid chamber (first ink transport unit) and the front stage of the ink chamber (second ink transport unit)
The ink ejection characteristics (improvement of ink ejection speed) can be improved by optimally designing the drive waveform applied to the ink transport unit).

(Third Embodiment) FIG. 9 is a diagram showing an ink jet head of a third embodiment and corresponds to claim 4. The process flow for manufacturing the inkjet head of the third embodiment is the same as that of the inkjet head of the first embodiment, and will not be repeated. 9 (A) and 9 (B) are shown in FIG. 9 (C).
FIG. 3 is a sectional view taken along line AA and a sectional view taken along line BB. The ink transport unit of the ink jet head of the third embodiment is configured such that the ink supply paths 91a, 91b, 91c ... Are separated by the partition wall with fluid resistance 63 and the ink transport unit is installed there. The fluid resistance is processed so as to have a directional resistance. For example, the surface roughness is processed so as to have directionality, or the cross-sectional area is processed so as to have directionality. By doing this, the ink is pushed out by the amount of the fluid resistance difference between the left and right with one amplitude of the diaphragm.
Therefore, if one ink transport unit is installed, the function can be achieved and a space-saving design can be achieved.

(Fourth Embodiment) FIG. 10 is a diagram showing an ink jet head of a fourth embodiment and corresponds to claim 5.
The process flow for manufacturing the ink jet head of the fourth embodiment is the same as that of the ink jet head of the first embodiment, and will be omitted. 10A and 10B are the same as FIG.
It is an AA sectional view and a BB sectional view of (C). Example 4
The inkjet head is configured such that a plurality of ink transport units are installed in one ink flow passage 91. Since no specially shaped fluid resistance is placed, the individual electrodes 94a, 9 are provided below the ink flow path 91 via the individual diaphragm 64 and the gap.
4b, 94c ... are arranged side by side. The operation is to attract ink by bending it in order from the diaphragm on the common channel side,
Next, the ink is pushed out to the supply destination by sequentially recovering from the vibration plate on the common flow path side. Therefore, although a plurality of ink transport units are installed, it is possible to transport more ink than the ink jet head of the fourth embodiment, and the degree of freedom in designing the ink flow path can be increased by properly using the ink according to the purpose.

(Fifth Embodiment) FIG. 11 is a diagram showing an ink jet head of a fifth embodiment and corresponds to claim 6.
Note that the process flow for manufacturing the inkjet head of the fifth embodiment is substantially the same as the process flow shown in the first embodiment, and will be omitted. The inkjet head of the fifth embodiment has the structure of the inkjet head of the fourth embodiment, in which appropriate protrusions 97a and 97b are formed from the nozzle substrate 50 side to the center side of the vibration plate 64, and the vibration plate 64 is normally (not bent). At this time, the height is processed so that the protrusions 97a and 97b can be touched. Therefore, the protrusions 97a, 97b
When is in contact with the vibrating plate 64, there is a large fluid resistance to the ink. Here, a case where two ink transport units are installed in the ink supply path 91 will be described. The operation is as follows. First, a drive signal is applied to the individual electrode 94b to bend the diaphragm on the common flow path side to draw in ink from the common ink flow path (FIG. 11A), and the drive signal is supplied to the individual electrode 94a of the next ink transport unit. Then, the vibration plate 64 is bent to further draw in the ink (FIG. 11B). Next, the drive signal of the individual electrode 94b on the common ink flow path side is set to 0, and the vibrating plate 64 is set.
Is recovered and is separated from the common ink flow path by the protruding portion 97b (FIG. 11C). Further, the drive signal for the next individual electrode 94a is set to 0 to recover the vibration plate 64 and eject the ink to the supply destination (FIG. 11D). In the ink jet head of the fifth embodiment, since the fluid resistance of the special shape is not placed, the individual vibration plate 64 and the individual electrodes for ink supply 94a and 94b are arranged below the ink flow path 91 via the gap. Therefore, at least 2 ink transport units
Although it is possible to individually install the inks, it is possible to significantly reduce the backflow ink, and it is possible to improve the efficiency of ink transport compared to the ink transport unit of the fourth embodiment, and it is possible to freely design the ink flow path by properly using the ink transport unit. The degree increases.

[0049]

As is apparent from the above description, the present invention has the following effects. According to the ink jet head of claims 1 and 2, and the ink jet recording apparatus of claim 8, when the cross-sectional area of the ink supply path is small, or when the length of the ink supply path is large, that is, the fluid resistance is large and the ink Even when the flow becomes difficult, the ink transport unit is added to the ink flow path, whereby the fluid resistance can be relaxed and the ink can be stably supplied. Therefore, the degree of freedom in arranging the ink supply path is increased, and the ink jet head can be easily designed. Also,
Since the area of the ink supply path can be reduced, a high integration of a large number of nozzles is possible, and the printing speed per unit area can be increased in the applied machine. On the other hand, from a different point of view, the number of nozzles of the inkjet head corresponding to the case where the printing speed is the same is small, the chip area is small, and the cost can be reduced accordingly. As a result, it is possible to adopt a configuration adapted to the matrix nozzle arrangement.

According to the ink-jet head of the third aspect, it is possible to supply the ink amount corresponding to the ink ejection amount by synchronizing with the driving waveform / timing of the ink ejection, and it is possible to prevent excessive or insufficient supply of ink. Can be resolved,
Printing can be continued with a stable ink ejection amount, and printing quality is improved. Further, by optimally matching the ink ejection timing and the ink transportation timing, the ink reverse flow rate at the time of ejection can be reduced, and the ejection speed and ejection mass can be improved. From the opposite viewpoint, lower voltage driving becomes possible.

According to the ink jet head of the fourth aspect, the ink can be pumped by installing only one set of the ink transport unit, and the space-saving design can be achieved. Therefore, each electrode pitch and each nozzle pitch interval can be made small, the electrode substrate integration corresponding to the high integration of nozzles can be realized, and the actuator can be made light, thin, short, and low cost.

According to the ink jet head of the fifth aspect, since the ink supply path is formed by a plurality of ink transport units, it is stable even if the distance between the ink pressurizing liquid chamber and the common ink flow path becomes large. Thus, the ink can be transported and the degree of freedom in designing the inkjet head is increased.

According to the ink jet head of the sixth aspect, the backflow of the ink is shut out by the protruding fluid resistance, so that the ink can be transported more accurately.

According to the seventh aspect of the present invention, the ink transport unit is manufactured by simultaneously forming the structure of the ink discharge portion of the electrostatic ink jet and the process of forming the structure of the ink transport unit in the same step. It is possible to manufacture at low cost without increasing the cost.

[Brief description of drawings]

FIG. 1 is a perspective view and a side sectional view of an inkjet recording device using an electrostatic inkjet head of the present invention.

FIG. 2 is a partially cutaway perspective view and a side sectional view of a conventional electrostatic ink jet head to which the present invention is applied.

FIG. 3 is an exploded perspective view of the electrostatic ink jet head of the present invention.

FIG. 4 is a cross-sectional view showing the process flow for manufacturing the electrostatic ink jet head of Example 1 of the present invention.

FIG. 5 is a cross-sectional view showing a process flow continued from FIG.

FIG. 6 is a cross-sectional view showing a process flow continued from FIG.

FIG. 7 is a diagram illustrating a drive circuit of an electrostatic ink jet head according to a second embodiment.

FIG. 8 is a diagram showing drive waveforms of the drive circuit shown in FIG. 7.

FIG. 9 is a schematic sectional view showing an electrostatic ink jet head of Example 3.

FIG. 10 is a schematic cross-sectional view showing an electrostatic ink jet head of Example 4.

FIG. 11 is a schematic cross-sectional view showing an electrostatic ink jet head of Example 5.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Recording device main body, 2 ... Printing mechanism part, 13 ... Carriage, 14 ... Inkjet head, 15 ... Ink cartridge, 50 ... Nozzle substrate, 51 ... Nozzle, 60 ... Vibrating plate substrate, 62 ... Ink liquid chamber, 63 ... Partition wall , 64 ... Vibration plate, 65 ... Fluid resistance, 70 ... Electrode substrate, 71 ... Silicon oxide film, 72 ... Electrode, 73 ... Vibration chamber, 74 ... Ink ejection individual electrode, 75 ... Protective film, 76 ... Common ink flow path , 8
0 ... FPC, 81 ... Silicon nitride film, 82 ... Electrode pad, 83 ... Bump, 84 ... Spacer, 91 ... Ink supply path, 93 ... Vibration chamber, 94 ... Ink supply individual electrode, 95
... Protective film, 96 ... Driver ICs, 97a, 97b ... Protrusions.

Claims (8)

[Claims] 1. An ink jet head comprising a plurality of nozzles, each pressurized liquid chamber communicating with each nozzle, and a common ink flow path for supplying ink to each pressurized liquid chamber via an ink supply path, A vibrating plate forming a part of the ink supply path, and an electrode substrate on which the ink supplying individual electrodes are arranged to face the vibrating plate via a gap, and the vibrating plate is deformed by electrostatic force. An inkjet head characterized in that the ink is transported by means of. 2. An ink jet head comprising a plurality of nozzles, each pressurizing liquid chamber communicating with each nozzle, and a common ink flow passage for supplying ink to each pressurizing liquid chamber via an ink supply passage, A vibrating plate that forms a part of the pressurized liquid chamber and the ink supply path, and an electrode substrate on which the ink ejecting individual electrode and the ink supplying individual electrode are opposed to each other via a gap with respect to the vibrating plate. Then, the ink jet head is characterized in that the vibration plate is deformed by electrostatic force to transport the ink and eject the ink. 3. The ink jet head according to claim 2, wherein the drive waveforms of the individual ink supply electrodes are drive waveforms that are synchronized with the drive waveforms of the individual ink ejection electrodes. 4. The ink jet head according to claim 1, wherein the inlet portion and the outlet portion of the ink supply path each have a directional fluid resistance. 5. The ink jet head according to claim 1 or 2, wherein the ink supply path has a plurality of sets of the vibration plate and individual electrodes for ink supply, and ink is transported by interlocking each part of the vibration plate. An inkjet head characterized in that. 6. The ink jet head according to claim 5, wherein the ink supply path includes a fluid resistance projecting toward the opposite side of the vibrating plate in the flow path. 7. The method of manufacturing an inkjet head according to claim 1, wherein the pressurized liquid chamber and the ink supply path are formed in the same step, and the individual ink ejection electrode and the ink are formed. A method for manufacturing an ink jet head, characterized in that the supply individual electrodes are formed in another same step. 8. An ink jet recording apparatus using the ink jet head according to any one of claims 1 to 6.