JPH11170536A - Ink jet type head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet type head for obtaining a good print image by supplying sufficient ink continuously while suppressing mutual electrical interference among a plurality of ink jet electrodes 3 thereby jetting ink stably at all times. SOLUTION: An ink jet type head comprises a plurality of electrode substrates 1 laminated through a spacer 2, ink channels 5 formed between the plurality of electrode substrates 1 and the spacer 2, ink jet stripe electrodes 3 formed on one side of the plurality of electrode substrates 1 while facing a recording medium at the forward end thereof, means 7a for supplying the ink jet electrode 3 with a pulse signal superposed on a bias voltage, and a pulse signal supply means 8. The ink channel 5 comprises means for circulating ink, and means for applying a second bias voltage to each conductor layer 4 formed on the other side of the plurality of electrode substrates 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink-jet type head device, and more particularly to an ink-jet head device which discharges a pigment ink containing charged coloring material particles toward a recording medium by electrostatic pressure. The present invention relates to an ink jet recording head device for performing recording on a recording medium.

[0002]

2. Description of the Related Art In general, a recording apparatus which discharges liquid ink as small droplets in the direction of a recording medium and performs dot recording on the recording medium to record a print or an image is known as an ink jet printer. Have been.
This ink-jet printer generates less noise than recording methods of other recording devices, and performs recording directly on a recording medium, so that the number of parts is smaller than that of recording methods of other recording devices. And has the advantage that it can be realized, and is attracting attention as a technology capable of recording on plain paper.

Here, as a recording method in an ink jet printer, a recording method in which bubbles are generated by heat generated by a heating element and ink droplets are ejected by the pressure of the bubbles (for example, disclosed in Japanese Patent Publication No. 56-9429). And a recording method (for example, disclosed in Japanese Patent Publication No. 53-12138) in which a mechanical pressure is generated due to a volume change due to distortion of a piezoelectric element, and ink droplets are ejected by the mechanical pressure.

[0004] In these two recording methods, the ejection amount of each ink droplet recorded in a dot form on a recording medium is constant. Therefore, when a color image is printed, the density between the dot-like recording areas is low. Is spatially changed to perform pseudo gradation expression, but in this gradation expression, it is difficult to print a color image with a high gradation equivalent to a photograph. And
In order to print an image with a higher gradation, it is necessary to perform gradation expression by so-called area modulation in which each dot-shaped recording area is changed. Since the amount is constant, it is extremely difficult to perform gradation expression by area modulation.

In order to overcome such difficulties, an ink-jet head device in an ink-jet printer is provided with an electrode substrate, an ink flow path is formed in the electrode substrate, and an ink discharge electrode is arranged and formed. Using the electrostatic force of the discharge electrode, the ink or the color material particles in the ink are discharged toward the recording medium,
2. Description of the Related Art An ink jet head device for printing an image on a recording medium has been proposed.

One such ink-jet type head device is disclosed in Japanese Patent Application Laid-Open No. 56-4467 and the like. Ink is discharged from an ink ejection electrode toward a recording medium by using electrostatic attraction. A method of ejecting and printing an image on a recording medium, and WO93 / 11866: PC
An ink jet recording method disclosed in T / AU92 / 00665, which uses an ink containing charged coloring material particles and increases the concentration of the coloring material particles in the direction from the ink ejection electrode to the recording medium. This is a method of ejecting and printing an image on a recording medium.

Further, as this type of ink jet head device, a device having a configuration in which a plurality of electrode substrates are arranged, that is, a so-called multi-head device has been proposed.

FIG. 12 is a perspective view showing an example of a main configuration of such a known multi-head device.

In FIG. 12, reference numeral 121 denotes an electrode substrate;
2 is a spacer, 123 is an ink ejection electrode, and 124 is an ink flow path.

The electrode substrate 121 is made of an insulating spacer 1
A multi-head device is formed by laminating a plurality of sheets with the ink discharge electrodes 123 arranged on one surface. The position of the tip of the electrode substrate 121 is
It is configured to protrude beyond the position of the tip of the spacer 122, and the adjacent electrode substrate 121 and the spacer 122
The groove formed by the above is an ink flow path 124. The ink flows through the ink flow path 124 in the direction of the arrow shown in FIG. For example, a bias voltage of about 2 kV is applied to each of the ink ejection electrodes 123, and when ink is ejected, the bias voltage is superimposed on the corresponding ink ejection electrode 123 by 5%.
A pulse signal having an amplitude of about 00 V is supplied.

In this multi-head device, the amount of ink ejected onto the recording medium can be controlled by changing the signal width of the pulse signal, and the dot-shaped recording area formed on the recording medium can be controlled. Can be controlled.

[0012]

By the way, the above-mentioned known multi-head device has an advantage that the dot-shaped recording area formed on the recording medium can be controlled. Since the ejection electrodes 123 individually eject ink droplets corresponding to the print pattern to be recorded on the recording medium, one ink ejection electrode 123 and two ink ejection electrodes adjacent to the ink ejection electrode 123 are used depending on the print pattern. If the values of the pulse signals applied to the ink discharge electrodes 123 are different, distortion occurs in the electric field distribution at the tip of any one of the ink discharge electrodes 123 due to electrical mutual interference (crosstalk) between these ink discharge electrodes 123. Become like

FIG. 13 is an explanatory diagram showing an example of a state of an electric field distribution generated by three ink ejection electrodes in the known multi-head device.

As shown in FIG. 13, a pulse signal amplitude (500 V) is applied to one ink discharge electrode 123b so as to be superimposed on a bias voltage (2 kV), and an ink discharge electrode adjacent to one side of the ink discharge electrode 123b is provided. 123a is superimposed on the bias voltage (2 kV) and the pulse signal amplitude (5
00V) is applied to the ink discharge electrode 123c adjacent to the other side of the ink discharge electrode 123b.
kV), the ink ejection electrode 1
The tip of the ink discharge electrode 123b is affected by the difference in voltage between the tips of the adjacent ink discharge electrodes 123a and 123c. Is not ejected straight toward the recording medium.

As described above, in the known multi-head device, depending on the conditions of the printing pattern, the ink may not be applied to the surface of the recording medium in the vertical direction but applied in a direction slightly deviated from the vertical direction. Therefore, there is a problem that not only can stable ink ejection not always be performed, but also a good printed image cannot be obtained.

On the other hand, recently, in order to solve such a problem, a multi-head device which is provided with a means for suppressing electric field interference between adjacent recording electrodes and constantly stably ejects ink has been developed. No. 9-234870.

The multi-head device disclosed in Japanese Patent Application Laid-Open No. 9-234870 is provided with a plurality of injection needle type recording electrodes and barrier electrodes arranged between the recording electrodes, and each of the barrier electrodes works as a shield. , In which electric field interference between adjacent recording electrodes is suppressed.

However, Japanese Patent Application Laid-Open No. Hei 9-23487 describes
The multi-head device disclosed in No. 0 can suppress electric field interference between the adjacent recording electrodes for the time being, but uses a recording electrode with a sharp tip and circulates ink inside the multi-head device. Therefore, when printing by aggregating and flying the colorant particles in the ink,
When continuous printing is performed, there is a new problem that the consumption of colorant particles progresses and it becomes impossible to obtain a printed image of a sufficient density on a recording medium as time passes.

The present invention solves these problems. It is an object of the present invention to suppress electric mutual interference between a plurality of ink ejection electrodes, to supply a sufficient amount of ink continuously, and to maintain a stable state at all times. It is an object of the present invention to provide an ink jet type head device which performs a proper ink ejection and obtains a good printed image.

[0020]

In order to achieve the above object, an ink jet head device according to the present invention supplies a pulse signal superimposed on a bias voltage to ink ejection electrodes formed on one surface of a plurality of electrode substrates. Forming a conductive layer on the other surface of the plurality of electrode substrates, and forming a second conductive layer on the conductive layer.
And an ink circulating means for circulating and flowing the ink through the ink flow path.

According to the above means, the conductive layers to which the second bias voltage is applied are arranged between the adjacent ink ejection electrodes, and each conductive layer has a role of an electrostatic shield. Even if a different voltage is applied between adjacent ink ejection electrodes corresponding to the pattern, electrical interference between the ink ejection electrodes based on the different voltages is suppressed by the conductor layer, and an electrostatic field at the tip of the ink ejection electrode is suppressed. Of the electric field distribution is significantly reduced. In addition, since each of the ink discharge electrodes is formed in a band shape and the ink is circulated using the ink circulating means, the ink is always stably discharged from the tip of the ink discharge electrode, and a good print image having a constant density is obtained. can get.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In an embodiment of the present invention, an ink jet head device comprises: a plurality of electrode substrates laminated via spacers; an ink flow path formed between the plurality of electrode substrates and the spacers; A band-shaped ink ejection electrode formed on one surface of the plurality of electrode substrates and having a tip facing the recording medium; and a bias voltage application unit and a pulse signal supply unit for supplying a pulse signal superimposed on a bias voltage to the ink ejection electrode. An ink circulating means for circulating and flowing ink through the ink flow path; and forming a conductor layer on each of the other surfaces of the plurality of electrode substrates, and supplying a second bias voltage to each conductor layer. And second bias voltage applying means.

According to the embodiment of the present invention, the ink discharge electrodes are formed on one surface of the plurality of electrode substrates, and the conductor layers are formed on the other surface, and a second bias voltage is applied to each conductor layer so as to be adjacent to each other. Since the ink discharge electrodes are electrostatically shielded by each conductor layer, even if different voltages are applied to adjacent ink discharge electrodes, the electric field generated between the ink discharge electrodes terminates in the conductor layer, As a result, no matter what printing pattern voltage is applied between the adjacent ink ejection electrodes, no distortion occurs in the electric field distribution based on the electric mutual interference between the adjacent ink ejection electrodes. Further, since each of the ink discharge electrodes is formed in a band shape and the ink is circulated through the ink flow path formed at the tip of each of the ink discharge electrodes using the ink circulation means, The colorant particles of the ink agglomerated at the tip of the ink are not reduced at the time of printing, the ink is always stably discharged from the tip of the ink discharge electrode, and a good print image with a constant density is recorded on the recording medium. Can be.

In one embodiment of the present invention, in the ink jet head device, the second bias voltage applying means generates an output voltage higher than the output voltage of the bias voltage applying means.

According to one embodiment of the present invention, since the second bias voltage higher than the bias voltage applied to the ink ejection electrode is applied to the conductive layer, as described above, the conductive layer is Acts as an electrical shield, has the function of suppressing electrical mutual interference between adjacent ink ejection electrodes, and increases the amount of charged colorant particles dispersed in the ink toward the ink ejection electrode side from the conductor layer side. Can be agglomerated.

In another embodiment of the present invention,
The ink jet type head device has a conductor layer provided on the entire other surface of the plurality of electrode substrates or a band having a width equal to or larger than the width of the band ink discharge electrode.

According to another embodiment of the present invention, when the ink ejection electrode is formed in a band shape, a region where the colorant particles in the ink in the ink flow path are aggregated is locally formed. This can prevent the ink flow path from being clogged with the aggregated ink.

In one example of another embodiment of the present invention, in the ink jet head device, each strip-shaped conductor layer is embedded in the other surface of the electrode substrate.

According to another embodiment of the present invention, since the conductor layer is embedded in the electrode substrate, the width of the ink flow path on the front side of the ink discharge electrode is reduced by the conductor layer. Therefore, the ink smoothly flows through the ink flow path.

[0030] In still another embodiment of the present invention, an ink jet type head device comprises a silicon substrate in which a plurality of electrode substrates are formed with an oxide film on one surface and an ion implantation layer serving as a conductor layer on the other surface. , A strip-shaped ink ejection electrode is formed on the oxide film, and the ion-implanted layer is 4 × 1
It has an ion carrier concentration of 0 ¹⁸ / cm ³ or more. According to still another embodiment of the present invention, since a plurality of electrode substrates can be formed from one silicon wafer, it is possible to form an electrode substrate whose thickness, dimensions, etc. are set with high processing accuracy. In addition, the space where the colorant particles in the ink are aggregated in the ink flow path can be localized, and the ink flow path can be prevented from being clogged by the aggregated ink.

In another embodiment of the present invention, in the ink jet head device, the ion implantation layer (conductor layer) includes a plurality of silicon substrates (electrode substrates).
Is provided on the entire surface of the other surface, or a band having a width equal to or greater than the width of the band-shaped ink ejection electrode.

According to still another embodiment of the present invention, when the ink smoothly flows through the ink flow path and the ion-implanted layer (conductor layer) is formed in a strip shape, the ink is aggregated. It is possible to prevent the ink flow path from being clogged by the ink.

In a preferred example of still another embodiment of the present invention, in the ink jet head device, the width of the strip-shaped conductor layer is set to 1.5 times the width of the ink discharge electrode. .

According to still another preferred embodiment of the present invention, if the width of the strip-shaped conductor layer is set to 1.5 times the width of the ink discharge electrode, the entire surface of the other surface of the electrode substrate is formed. In this case, the colorant particles in the ink can be sufficiently aggregated at the tip of the ink discharge electrode.

[0035]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1A, 1B and 1C are views showing the construction of a first embodiment of an ink jet head device according to the present invention, wherein FIG. 1A shows the main structure of an ink jet recording head. FIG. 2B is a schematic diagram showing a portion, FIG. 2B is a perspective view showing a portion including one electrode substrate, and FIG. FIG. 2 shows an example of an ink jet recording apparatus using the ink jet head device shown in FIG. 1A, and shows only main components of the ink jet recording apparatus.

In FIGS. 1A, 1B and 1C, 1
Is an electrode substrate, 2 is a spacer, 3 is a strip-shaped ink ejection electrode, 4 is a conductive layer, 5 is an ink flow path, 6 is ink, 7 is a bias power supply, 8 is a pulse signal generation source, and 9 is a drive circuit. .

In FIG. 2, reference numeral 10 denotes an ink jet head device, 11 denotes an ink tank, 12a denotes an ink supply pump, 12b denotes an ink discharge pump, 13 denotes an ink circulation path, 14 denotes an ink introduction path, and 15 denotes an ink introduction path. An aggregation electrode, 16 is an ink aggregation power supply, 17 is a counter electrode, 18 is a recording medium, and the same components as those shown in FIG. 1A are denoted by the same reference numerals.

As shown in FIGS. 1A to 1C,
A plurality of electrode substrates 1 are stacked with spacers 2 interposed therebetween, and band-shaped ink ejection electrodes 3 are formed on one surface,
The conductor layer 4 is formed on the entire other surface. The lamination direction of the electrode substrate 1 is the main scanning direction when printing, and the lamination number is 1
It is chosen to be equal to the number of dots for the line. The spacer 2 is configured such that the height of the tip is lower than the height of the tip of the substrate electrode 1, thereby providing a groove for forming the ink flow path 5 between the adjacent electrode substrate 1 and the spacer 2. . In the ink flow path 5, FIG.
In (a), the ink 6 flows in a direction perpendicular to the paper surface. The electrode substrate 1 is made of an insulating member such as ceramics, and has a band-shaped ink ejection electrode 3 and a conductor layer 4.
Are formed on one surface and the other surface of the electrode substrate 1 by means such as electroless plating or vacuum deposition. In this case, the tip of the ink discharge electrode 3 is cut so as to concentrate the electrostatic field on the tip, and the tip of the ink discharge electrode 3 and the tip of the conductor layer 4 are at the same height. Has become.

Each ink ejection electrode 3 is connected to a bias voltage source 8 through a pulse signal generating source 8, and each conductor layer 4 is directly connected to the bias voltage source 8.
Each pulse signal source 8 is individually connected to a drive circuit 9. By making such a connection, the bias voltage Vb output from the bias voltage source 8 is supplied to each of the ink ejection electrodes 3 and each of the conductor layers 4, and each of the ink ejection electrodes 3
When the corresponding pulse signal generation source 8 receives the drive output of the drive circuit 9 and generates a pulse signal, the bias voltage V
The pulse signal superimposed on b is selectively supplied.

As shown in FIG. 2, the ink-jet type head device 10 includes the ink discharge electrode 3 as described above, and the ink introduction path 14 and the ink circulation path 1.
3, connected to the ink tank 11 via an ink supply pump 12a and an ink circulation path 13, and further provided with an ink introduction path 14, an ink circulation path 13, an ink discharge pump 12b,
It is connected to the ink tank 11 via the ink circulation path 13. The ink aggregation electrode 15 is connected to the ink introduction path 14, and the ink aggregation power supply 16 is connected between the ink ejection electrode 3 and the ink aggregation electrode 15. The recording medium 18 is arranged on the counter electrode 17 which is connected to the ground.

The ink jet recording apparatus having the above configuration operates as follows.

When the ink jet recording apparatus performs print recording, the ink 6 in the ink tank 11 flows through the ink circulation path 13 in the direction of the arrow in FIG. Is supplied to the head unit 10. Then, when the ink 6 passes through the ink introduction path 14, the electric field from the ink aggregation electrode 15 toward the ink ejection electrode 3 is formed by the ink aggregation power supply 16 connected between the ink aggregation electrode 15 and the ink ejection electrode 3. In addition, the charged colorant particles dispersed in the ink 6 aggregate near the tip of the ink discharge electrode 3. As will be described later, when a voltage exceeding the threshold voltage Vth is applied to the ink discharge electrode 3, the aggregated colorant particles are discharged from the tip toward the grounded counter electrode 17, and Recording medium 1
8 is printed.

When printing is performed by the ink jet recording device, the ink 6 flows through the ink flow path in the ink jet type head device 10 and is discharged from the tip of the ink discharge electrode 3 to be used for printing on the recording medium 18. You. The remaining ink 6 not used for printing flows from the ink introduction path 14 through the ink circulation path 13 in the direction of the arrow in FIG. 2 and is returned to the ink tank 11 by suction by the ink discharge pump 12b. The ink 6 returned to the ink tank 11 is used for printing on the ink jet head device 10 again.

Further, the ink jet head device of the first embodiment having the above configuration operates as follows.

In the ink jet type head device 10, a proximity opposing electrode (not shown in FIGS. 1 and 2) is arranged close to the band-shaped ink ejection electrode 3, and the ink ejection electrode 3 to which the bias voltage Vb is applied. FIG. 1 shows a state in which a voltage lower than the bias voltage Vb is applied to the adjacent counter electrode.
An electric field is generated in the direction indicated by the arrow h in FIG. In the ink 6 flowing in the ink flow path 5 in the direction perpendicular to the paper surface, the charged colorant particles in the ink 6 aggregate around the tip of the ink discharge electrode 3 due to the electric field in the direction of the arrow h. The agglomerated colorant particles generate an electrostatic repulsion between the banded ink discharge electrode 3 and the electric field in the direction of the arrow h, and the ink 6 at the tip of the ink discharge electrode 3 flies toward the close opposing electrode. try to. On the other hand, since the surface tension of the ink 6 is opposite to the electrostatic repulsion, the voltage applied to the band-shaped ink ejection electrode 3 is changed to the threshold voltage Vt as shown in FIG.
As long as the length does not exceed h, the ink 6 does not fly from the tip of the ink discharge electrode 3 toward the near counter electrode.

Incidentally, the bias power supply 8 generates a bias voltage Vb lower than the threshold voltage Vth.
The voltage is applied to the ink ejection electrode 3 and the conductor layer 4. Then, only when printing is performed, a drive signal for printing is given from the drive circuit 9 to the pulse signal generation source 8, and the pulse signal of the predetermined amplitude Vej generated by the pulse signal generation source 8 is superimposed on the bias voltage Vb and added. , The added voltage becomes higher than the threshold voltage Vth.

In the ink jet head device 10 of the first embodiment, only the ink ejection electrode 3 to which the added voltage in which the pulse signal is superimposed on the bias voltage Vb applies the ink is ejected. At the time of printing, a drive signal for printing is given from a drive circuit 9 to a pulse signal generation source 8 connected to an ink discharge electrode 3 corresponding to a dot position to be printed in one line. All the pulse signal generating sources 8 to which the printing drive signal is applied generate a pulse signal, and the ink 6 is simultaneously ejected from the ink ejection electrode 3 to which the pulse signal is supplied, thereby performing printing on the recording medium 18. Things.

In this type of ink jet head device, when the ink ejection electrode 3 supplied with the pulse signal from the pulse signal generating source 8 and the ink ejection electrode 3 not supplied with the pulse signal are adjacent to each other, these ink ejection electrodes 3 As described above, since the voltages applied to the electrodes 3 are different, electric mutual interference occurs between the ink ejection electrodes 3.

On the other hand, in the ink jet head device 10 of the first embodiment, in order to suppress the electric mutual interference between the ink discharge electrodes 3 having different applied voltages, the bias potential is set between the adjacent ink discharge electrodes 3. Since the conductor layer 4 to which Vb is applied is provided, the conductor layer 4 functions as a shield electrode, and the occurrence of electrical interference is suppressed. Note that the conductor layer 4 is configured to have the same height as the ink discharge electrode 3 and that a voltage exceeding the threshold voltage Vth is not applied. In addition, the ink 6 is not discharged from the tip of the conductor layer 4.

FIGS. 4A and 4B are characteristic diagrams showing an example of an electric field distribution state generated by three adjacent band-shaped ink ejection electrodes 3a, 3b, and 3c in the ink jet head device 10 of the first embodiment. (A), when only the bias potential Vb (2 kV) is applied, (b)
Is the bias potential Vb applied to the two ink ejection electrodes 3a and 3b.
In this case, a voltage (2.5 kV) obtained by superimposing a pulse signal and a pulse signal is applied.

However, each of the band-shaped ink ejection electrodes 3a, 3a
b, 3c and the conductor layers 4a, 4b each have a thickness of 35.
The interval between the band-shaped ink ejection electrodes 3a, 3b, and 3c is 100 μm.

As shown in FIG. 4A, the initial conditions of the voltage applied to each of the ink discharge electrodes 3a, 3b, 3c are as follows.
When a bias voltage Vb of 2 kV is applied to all of the ink discharge electrodes 3a, 3b, and 3c, the electric field near each of the ink discharge electrodes 3a, 3b, and 3c becomes
Are symmetrical with respect to the central axis.

On the other hand, as shown in FIG. 4B, during operation of the ink jet head device 10, a bias voltage Vb of 2 kV and a pulse signal of amplitude 500 V are superimposed on the two ink ejection electrodes 3a and 3b. 2.
An additional voltage of 5 kV is applied, and the other ink ejection electrodes 3 c
Even if a bias voltage Vb of 2 kV is applied to the conductive layer 4 and the conductive layer 4, the ink ejection electrode 3b is sandwiched between the conductive layers 4a and 4b to which the bias voltage Vb of 2 kV is applied. The ink ejection electrodes 3
The electric fields near a, 3b, and 3c maintain symmetry with respect to the center axis of each of the ink ejection electrodes 3a, 3b, and 3c.

FIG. 5 is a characteristic diagram showing the angular distribution of the electric field at the tip of the ink discharge electrode 3.

In FIG. 5, the vertical axis is the electric field strength indicated by MV / m, and the horizontal axis is the angle indicated by deg. In this case, a curve a is for the ink jet head device 10 of the first embodiment, and a curve b is for a known head device of this type having no conductive layer 4.

As shown in FIG. 5, in the known head device having no conductive layer 4, the position where the electric field is maximum is shifted from the center angle (0 degree), whereas the conductive layer 4 In the ink jet head device 10 according to the first embodiment, the position where the electric field is maximized substantially coincides with the center angle (0 degree).

As described above, in the ink jet head device 10 of the first embodiment, the two ink discharge electrodes 3a, 3b and 3b, 3c adjacent to each other are shielded by the conductor layer 4, and the occurrence of electrical interference occurs. Is suppressed, and two adjacent ink ejection electrodes 3a, 3b
The electric field distribution at the tip of the ink discharge electrode 3 is not distorted by the suppression of the electric mutual interference between the ink discharge electrodes 3b and 3c, and stable ink discharge can be performed.

The ink jet head device 10 of the first embodiment uses the ink discharge electrodes 3 in the form of strips and circulates the ink 6 flowing through the ink flow path 5, so that the ink 6 is dried. In this way, it is possible to constantly perform stable ink ejection at a constant density without causing the colorant particles of the ink 6 to run out during continuous printing.

FIGS. 6A and 6B are diagrams showing a second embodiment of the ink jet head device according to the present invention, wherein FIG. 6A shows the main components of the ink jet recording head. FIG. 2B is a cross-sectional view showing a portion including one electrode substrate.

In FIGS. 6A and 6B, reference numeral 7a denotes the first
Is a second bias power supply, and the other components are the same as those shown in FIGS. 1A to 1C.

The first bias power supply 7 a generates the bias voltage Vb 1 and is connected to the ink ejection electrode 3 via the pulse signal generation source 8. Second bias power supply 7
b is a bias voltage Vb2 higher than the bias voltage Vb1.
And is connected to the conductor layer 4.

The difference between the configuration of the second embodiment and the configuration of the first embodiment is that the configuration of the bias power supplies 7, 7a and 7b is different from that of the second embodiment in that only one bias power supply 7 is used. In contrast to the configuration in which the voltage Vb is applied to the ink ejection electrode 3 and the conductive layer 4, the first embodiment uses two bias power sources 7a and 7b and applies one bias voltage Vb1 to the ink ejection electrode 3 And the other bias voltage Vb2 is applied to the conductor layer 4, and there is no other difference between the second embodiment and the first embodiment. Therefore, further description of the configuration of the second embodiment is omitted.

FIG. 7 is a characteristic diagram showing the relationship among the bias voltages Vb1, Vb2, the threshold voltage Vth, and the amplitude Vej of the pulse signal in the second embodiment.

As shown in FIG. 7, the second bias voltage Vb2 applied to the conductive layer 4 from the second bias power supply 7b is applied to the ink ejection electrode 3 from the second bias power supply 7a. Higher than the voltage Vb1, and
Since the voltage is set to be lower than the threshold voltage Vth, the ink 6 is not ejected from the conductor layer 4. Then, a pulse having an amplitude Vej generated by the pulse signal generation source 8 corresponding to the print drive signal from the drive circuit 10 is superimposed on the ink discharge electrode 3 on the first bias voltage Vb1 applied from the bias power supply 7a. When the signal is applied, the voltage applied to the ink ejection electrode 3 becomes the threshold voltage Vt.
h, the ink discharge electrode 3
The ink 6 is ejected from the printer, and printing is performed.

During the period in which the ink 6 is not ejected, the second bias voltage Vb2 applied to the conductive layer 4 is higher than the first bias voltage Vb1 applied to the ink ejection electrode 3, so that FIG. As shown in b), an electric field is generated in the direction of the arrow from the conductive layer 4 toward the ink ejection electrode 3, and the electric field is dispersed by the electric field in the ink 6 flowing in the ink flow path 5. The colorant particles thus aggregated around the tip of the ink discharge electrode 3.

As described above, according to the second embodiment, the same effects as those obtained in the first embodiment can be obtained, and the charged colorant particles dispersed in the ink 6 can be ejected by the ink ejection. Since it is possible to aggregate near the tip of the electrode 3, unlike the first embodiment, there is no need to dispose the proximity counter electrode for aggregating the colorant particles outside the ink jet head device 10, and the parts The number of points can be reduced, and an ink jet head device can be obtained at low cost.

Next, FIGS. 8A and 8B are configuration diagrams showing a third embodiment of the ink jet head device according to the present invention, wherein FIG. 8A shows a portion including one electrode substrate. FIG. 3B is a perspective view, and FIG.

In FIGS. 8A and 8B, reference numeral 4a denotes a strip-shaped conductor layer. In addition, the same reference numerals as those shown in FIGS. 6A and 6B denote the same components. I have.

The strip-shaped conductor layer 4 a is configured to be slightly wider than the strip-shaped ink discharge electrode 3, for example, 1.5 times as wide as the strip-shaped ink ejection electrode 3, and is formed at a position facing the electrode substrate 1. ing.

The difference between the third embodiment and the second embodiment is that the third embodiment uses a strip-shaped conductor layer 4a and sandwiches the electrode substrate 1 with respect to the conductor layers 4 and 4a. And provided at a position facing the ink ejection electrode 3,
The second embodiment uses the planar conductor layer 4 and the electrode substrate 1
There is no difference in configuration between the third embodiment and the second embodiment in addition to the point that it is provided on the entire surface including the position facing the ink ejection electrode 3 with the interposition therebetween. Therefore, the third
Further description of the configuration of the embodiment will be omitted.

In the third embodiment, as in the second embodiment, the first layer applied to the ink ejection electrode 3 is applied to the conductor layer 4a.
Bias voltage Vb higher than the bias voltage Vb1
b2 is applied to generate an electric field between the conductive layer 4a and the ink discharge electrode 3 between the conductive layer 4a and the ink discharge electrode 3 with the ink flow path 5 interposed therebetween, and the electric field is dispersed in the ink 6. The charged colorant particles are aggregated near the tip of the ink discharge electrode 3. In this case, the width of the band-shaped ink ejection electrode 3 is set to, for example, about 100 μm, and the band-shaped conductive layer 4 is formed.
If the width of “a” is made wider than 100 μm, the ink flow path 5
The space in which the colorant particles are aggregated becomes smaller. Then, the width of the band-shaped conductor layer 4a is changed to the band-shaped ink ejection electrode 3.
Is selected so as to be 1.5 times as large as the width of the electrode substrate 1, the aggregating function of the colorant particles of the ink 6 can be made equivalent to the case where the conductor layer 4 is provided on the entire other surface of the electrode substrate 1. .

As described above, according to the third embodiment, it is possible to obtain substantially the same effect as that obtained in the first embodiment, and in addition, the colorant particles aggregate in the ink flow path 5. Since the space where the colorant particles are located can be reduced, it is possible to prevent the ink flow path 5 from being clogged by the high-concentration ink 6 in which the colorant particles are aggregated, and a highly reliable ink jet head device can be realized.

FIGS. 9A and 9B are diagrams showing the construction of a fourth embodiment of the ink jet head device according to the present invention, wherein FIG. 9A shows a portion including one electrode substrate 1. FIG. 1B is a perspective view, and FIG.

In FIGS. 9A and 9B, reference numeral 4b denotes a strip-shaped conductor layer embedded in the electrode substrate 1 and other components shown in FIGS. 6A and 6B. The same components are denoted by the same reference numerals.

The strip-shaped conductive layer 4a is formed to have the same width as or slightly wider than the width of the same strip-shaped ink discharge electrode 3 and is formed at a position facing the electrode substrate 1 therebetween. ing.

The difference between the fourth embodiment and the third embodiment is that the fourth embodiment has a band-shaped conductor layer 4b embedded in the electrode substrate 1 with respect to the conductor layers 4a and 4b. In contrast to the configuration, the third embodiment has
a is arranged on the surface of the electrode substrate 1, and there is no other structural difference between the fourth embodiment and the third embodiment. Therefore, further description of the configuration of the fourth embodiment will be omitted.

In the fourth embodiment, as in the second embodiment, the first layer applied to the ink ejection electrode 3 is applied to the conductor layer 4b.
Bias voltage Vb higher than the bias voltage Vb1
When b2 is applied, an electric field is generated between the conductive layer 4b and the ink discharge electrode 3 between the conductive layer 4b and the ink discharge electrode 3 with the ink flow path 5 interposed therebetween, and the electric field is dispersed in the ink 6. The charged coloring agent particles are aggregated near the tip of the ink discharge electrode 3.

As described above, according to the fourth embodiment, in addition to obtaining substantially the same effect as that obtained in the third embodiment,
Since the conductive layer 4b is embedded in the electrode substrate 1, the width of the ink flow path 5 between the ink discharge electrode 3 and the conductive layer 4b is not reduced, and the ink flow by the ink 6 is prevented. The function of preventing clogging of the road 5 can be further improved.

FIGS. 10 (a) and 10 (b) are views showing the construction of a fifth embodiment of the ink jet head device according to the present invention, wherein (a) shows a portion including one electrode substrate 1. FIG. And (b) is a cross-sectional view thereof.

10A and 10B, reference numeral 19 denotes a silicon substrate (electrode substrate), reference numeral 20 denotes an ion-implanted region (conductor layer), reference numeral 21 denotes a silicon oxide film.
The same components as those shown in (a) and (b) are denoted by the same reference numerals.

The silicon substrate 19 has a silicon oxide film 21 formed on one surface, the ink discharge electrodes 3 arranged and formed on the silicon oxide film 21, and an ion implantation region 20 formed on the other surface. .

The ion implantation region 20 is formed on the silicon substrate 19
Is implanted with ions having a carrier concentration of 4 × 10 ¹⁸ / cm ³ or more, and is formed on one entire surface of the silicon substrate 19. As the ions to be implanted, boron (B)
Or an acceptor such as phosphorus (P) or arsenic (As). In this case, since the carrier concentration of the ion implantation region 20 is set to 4 × 10 ¹⁸ / cm ³ or more, for example, when arsenic (As) is ion-implanted, the impurity band of the donor in the energy band structure is reduced. As a result, the potential overlaps with the conduction band so that the conductivity becomes almost equal to that of metal.
0 to the second bias voltage Vb2,
It can be used as equivalent to the conductor layer 4.

That is, in the fifth embodiment, the silicon substrate 19
Is used in place of the electrode substrate 1 of the first to fourth embodiments,
The ion implantation region 20 is used in place of the conductor layer 4 of the first and second embodiments.

In the fifth embodiment, not only can the conductor layer 4 be easily formed by utilizing a known semiconductor process, but also a very flat single-crystal silicon substrate 19 (electrode substrate 1). Since the substrate can be used, the processing accuracy of the ink jet head device 10 can be easily increased, and further, a plurality of silicon substrates 19 (electrode substrate 1) can be converted from one silicon wafer using a batch process. , So that the low-cost ink jet head device 10
Is obtained.

According to the fifth embodiment, it is possible to obtain substantially the same effects as those obtained in the first embodiment.

Next, FIGS. 11A and 11B are views showing the construction of a sixth embodiment of the ink jet head device according to the present invention, wherein FIG. 11A shows a portion including one electrode substrate 1. And (b) is a cross-sectional view thereof.

In FIGS. 11A and 11B, reference numeral 20a denotes a band-like ion-implanted region (conductor layer),
The same components as those shown in (a) and (b) are denoted by the same reference numerals.

The band-shaped ion implantation region 20 a is formed by implanting ions having a carrier concentration of 4 × 10 ¹⁸ / cm ³ or more into the silicon substrate 19. It is configured to be slightly wider than the width, and is arranged and formed at a position facing the silicon substrate 19 (electrode substrate 1).

In the sixth embodiment, a second bias voltage Vb2 higher than the first bias voltage Vb1 applied to the ink discharge electrode 3 is applied to the belt-like ion implantation region 20a, so that the ink flow path 5 An electric field is generated between the ink ejection electrode 3 and the band-shaped ion implantation region 20a from the band-shaped ion implantation region 20a toward the ink ejection electrode 3, with the charged colorant dispersed in the ink 6. The particles are aggregated near the tip of the ink discharge electrode 3. In this case, the width of the band-shaped ink ejection electrode 3 is set to, for example, about 100 μm, and the band-shaped ion implantation region 20a is formed.
Is wider than 100 μm, the space in the ink flow path 5 where the colorant particles are aggregated becomes smaller. If the width of the band-like ion-implanted region 20 is selected to be 1.5 times the width of the band-like ink ejection electrode 3, the function of aggregating the colorant particles of the ink 6 on the entire surface of the other surface of the silicon substrate 19 is achieved. This can be equivalent to the case where the ion implantation region 20 is provided.

As described above, according to the sixth embodiment, it is possible to obtain substantially the same effect as that obtained in the fifth embodiment.

[0092]

As described above, according to the present invention,
Ink discharge electrodes are formed on one surface of a plurality of electrode substrates, and a conductor layer is formed on the other surface, a bias voltage is applied to each conductor layer, and the space between adjacent ink discharge electrodes is electrostatically shielded by each conductor layer. Therefore, even if different voltages are applied to adjacent ink ejection electrodes, the electric field generated between each ink ejection electrode is terminated by the conductor layer, and distortion of the electric field distribution due to electric mutual interference between adjacent ink ejection electrodes is reduced. Will not occur. Also,
Each of the ink ejection electrodes is formed of a strip, and the ink is circulated through an ink flow path formed at the tip of each of the ink ejection electrodes by using an ink circulating means. The colorant particles of the ink agglomerated into the ink do not decrease during printing, the ink is constantly stably discharged from the tip of the ink discharge electrode, and a good printed image having a constant density can be recorded on the recording medium. . At all times
It is possible to stably eject the ink from the tip of the ink ejection electrode, and there is an effect that a good print image can be recorded on the recording medium.

Here, according to the second aspect of the present invention,
In addition to the above effects, there is no need to use the proximity counter electrode, so that the number of parts can be reduced accordingly.

According to the third and fourth aspects of the present invention, in addition to the above-mentioned effects, the fourth aspect of the present invention provides a strip-shaped electrode having the same width as or slightly wider than the width of the ink discharge electrode. The use of a conductor layer makes it possible to reduce the space in which color material particles aggregate in the ink flow path, thereby preventing clogging of the ink flow path due to high-concentration ink in which color material particles are aggregated. Thus, there is an effect that a highly reliable ink jet head device can be obtained.

According to the fifth aspect of the present invention, in addition to obtaining the same effects as those obtained by the fourth aspect of the present invention, a strip-shaped conductor layer is embedded in the electrode substrate. Therefore, there is an effect that the width of the ink flow path between the ink discharge electrode and the conductive layer is not reduced, and clogging of the ink flow path can be more completely prevented.

According to the sixth aspect of the present invention, in addition to the above effects, an ink discharge electrode is formed on an oxide film formed on one surface of a silicon substrate, and ion implantation is performed on the other surface by ion implantation. Since the region (conductor layer) is formed,
With the use of a known semiconductor process, an ion-implanted region (conductor layer) can be easily formed.
There is an effect that the processing accuracy can be sufficiently increased and a low-cost ink jet head device can be obtained.

According to the invention as set forth in claims 7 to 9, in addition to the same effect as that obtained by the invention as set forth in claim 6, in the invention as set forth in claim 8, a belt-like shape is provided. Since the ion implantation region (conductor layer) is formed, the same effect as that obtained by the invention of claim 4 can be obtained. In the invention of claim 9, claim 8
In addition to obtaining the same effect as the effect obtained by the invention described in (1), the width of the band-shaped ion implantation region (conductor layer) is set to 1.5 times the width of the ink discharge electrode, so that the silicon substrate There is an effect that the same aggregating function of the colorant particles of the ink can be provided as in the case where the ion implantation region (conductor layer) is provided on the entire other surface.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of an ink jet head device according to the present invention.

FIG. 2 is a schematic diagram showing an example of an ink jet recording apparatus using the ink jet head device shown in FIG.

FIG. 3 is a characteristic diagram showing a relationship among a bias voltage, a threshold voltage, and an amplitude of a pulse signal in the first embodiment.

FIG. 4 is an explanatory diagram showing an example of a state of an electric field distribution generated by three adjacent ink ejection electrodes in the ink jet head device of the first embodiment.

FIG. 5 is a characteristic diagram illustrating an angle distribution of an electric field at a tip portion of an ink ejection electrode.

FIG. 6 is a configuration diagram showing a second embodiment of the ink jet head device according to the present invention.

FIG. 7 is a characteristic diagram showing a relationship between two bias voltages, a threshold voltage, and an amplitude of a pulse signal in the second embodiment.

FIG. 8 is a configuration diagram showing a third embodiment of the ink jet head device according to the present invention.

FIG. 9 is a configuration diagram showing a fourth embodiment of the ink jet head device according to the present invention.

FIG. 10 is a configuration diagram showing a fifth embodiment of the ink jet head device according to the present invention.

FIG. 11 is a structural view showing a sixth embodiment of the ink jet head device according to the present invention.

FIG. 12 is a perspective view showing an example of a main configuration of a known multi-head device.

FIG. 13 is an explanatory diagram showing an example of a state of an electric field distribution generated by three ink ejection electrodes in a known multi-head device.

[Explanation of symbols]

 Reference Signs List 1 electrode substrate 2 spacer 3, 3a, 3b, 3c ink discharge electrode 4 conductive layer 4a, 4b strip-shaped conductive layer 5 ink flow path 6 ink 7 bias power supply 7a first bias power supply 7b second bias power supply 8 pulse Signal source 9 Drive circuit 10 Inkjet head device 11 Ink tank 12a Ink supply pump 12b Ink discharge pump 13 Ink circulation path 14 Ink introduction path 15 Ink aggregation electrode 16 Ink aggregation power supply 17 Counter electrode 18 Recording medium 19 Recording medium 19 Silicon substrate ( Electrode substrate) 20 ion-implanted region (conductor layer) 20a band-shaped ion-implanted region (band-shaped conductor layer) 21 oxide film

Continued on the front page (72) Inventor Atsushi Onose 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside the Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Seiji Yonekura 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Shinya Kobayashi, 1-1-1, Omika-cho, Hitachi City, Ibaraki Pref., Hitachi Research Laboratory, Hitachi, Ltd.

Claims (9)

[Claims] A plurality of electrode substrates laminated via a spacer, an ink flow path formed between the plurality of electrode substrates and the spacer, and formed on one surface of the plurality of electrode substrates.
An ink-jet head device comprising: a band-shaped ink ejection electrode having a leading end facing a recording medium; and a bias voltage application unit and a pulse signal supply unit that supply a pulse signal superimposed on a bias voltage to the ink ejection electrode.
An ink circulation means for circulating and flowing ink through the ink flow path; and a second bias for forming a conductor layer on the other surface of the plurality of electrode substrates and supplying a second bias voltage to each of the conductor layers. An ink jet head device comprising: a voltage application unit. 2. The ink jet head device according to claim 1, wherein said second bias voltage applying means generates an output voltage higher than an output voltage of said bias voltage applying means. 3. The device according to claim 1, wherein each of the conductor layers is provided on the entire other surface of the plurality of electrode substrates.
3. The ink jet head device according to claim 1. 4. The ink-jet head device according to claim 1, wherein each of the conductor layers has a band shape having a width equal to or larger than the width of the band-shaped ink discharge electrode. 5. The ink jet head device according to claim 4, wherein the strip-shaped conductor layer is embedded in the other surfaces of the plurality of electrode substrates. 6. The plurality of electrode substrates have an oxide film on one surface thereof,
The other side is made of a silicon substrate on which an ion implantation layer serving as the conductor layer is formed, the band-shaped ink ejection electrode is formed on the oxide film, and the ion implantation layer is 4 × 10
^2. The ink-jet head device according to claim 1, wherein the ink-jet head device has an ion carrier concentration of ¹⁸ / cm ³ or more. 7. The ink jet head device according to claim 6, wherein the ion implantation layer is provided on the entire other surface of the plurality of silicon substrates. 8. The ink jet head according to claim 6, wherein the ion-implanted layer has a band shape, and has a width equal to or greater than the width of the band-shaped ink ejection electrode. apparatus. 9. The method according to claim 4, wherein the strip-shaped conductor layer and the ion-implanted layer have a width 1.5 times the width of the strip-shaped ink ejection electrode. Inkjet head device.