JP3211284B2 - Ink jet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus for recording characters and images by flying ink toward a recording medium.

[0002]

2. Description of the Related Art As a conventional ink jet recording apparatus, there is known an ink jet recording apparatus which ejects an ink toward a recording medium by applying vibration energy to the ink, and which ejects the ink by applying electrostatic energy. More specifically, as the former, for example, a method in which vibration energy is applied to ink held in ink holding means by a piezoelectric vibrator (piezo element) and ejected from an orifice (Kaiser type ink jet recording apparatus, Japanese Patent Publication No. 53-12138)
Reference).

[0003] As the latter, a slit that opens from the ink holding portion toward the recording medium is formed, and recording electrodes corresponding to a large number of dots are arranged in the slit.
Placing a counter electrode behind the recording medium, individually applying a voltage to each recording electrode in accordance with print data, causing an electrostatic field between the applied recording voltage and the counter electrode,
An ink jet recording apparatus (slit jet recording apparatus, IEICE Transactions Volume C, Vol. J6) configured to fly ink onto a recording medium by the electrostatic attraction force.
8-C, no. 2, 1985).

[0004]

However, in the above-mentioned Kaiser-type ink jet recording apparatus, the volume change of the ink holding section due to the vibration of the piezo element is made sufficiently large in order to give the ink enough vibration energy to eject the ink. Since it is necessary to increase the size of the acting body, it is difficult to achieve a high-density multi-nozzle.

In a recording apparatus that generates an electrostatic field such as a slit jet recording apparatus, the distance between the recording electrodes cannot be reduced below a certain value in order to prevent crosstalk between adjacent recording electrodes. After all, there is a problem that a limitation is imposed in achieving a high-density multi-nozzle. Further, it is necessary to drive the recording electrodes in a divided manner in order to prevent electrostatic repulsion at the time of ink flying, and there is a problem that the recording speed is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an ink jet recording apparatus which can easily form a high-density multi-nozzle and can increase the recording speed.

[0007]

In order to achieve the above object, an ink jet recording apparatus according to the present invention has an ink chamber for holding ink and an ink provided with a nozzle directed from the ink chamber to a recording medium. A piezoelectric vibrator including a holding unit, a first region near the nozzle and facing the ink chamber, and a second region not facing the ink chamber;
A first electrode provided in the area, grounded; a second electrode provided in the second area; a third electrode provided on the back side of the recording medium with respect to the nozzle; Connected, applying a signal voltage to the second electrode to form an electric field between the first electrode and the second electrode, causing the piezoelectric vibrator to vibrate, and applying vibration energy to the ink in the ink holding means. A vibration energy applying means, connected to the third electrode, and applying a voltage to the second electrode to form an electrostatic field between the first electrode and the third electrode, thereby transferring ink from the ink holding means; A static electric field forming means for electrostatically attracting the recording medium toward the recording medium. Further, the first electrode is covered with a protective film.

[0008]

According to the above configuration, the ink held by the ink holding means is pushed out toward the recording medium by the vibration energy given by the piezoelectric vibrator, and is further electrostatically applied to the recording medium by the electrostatic energy of the electrostatic field forming means. Adsorbed. The start timing and the end timing of the application of the vibration energy and the application of the electrostatic energy do not necessarily need to coincide, but at least the vibration energy and the electrostatic energy need to be applied in a superimposed manner, and the vibration energy is lacking. In some cases, the ink does not fly toward the recording medium because the force that pushes the ink toward the recording medium does not act, and when the electrostatic energy is lacking, the force that electrostatically attracts the ink toward the recording medium is insufficient. Again, the ink does not fly towards the recording medium.

Further, since one electrode of the piezoelectric vibrator and one electrode of the electrostatic field forming means are also used, the space required for providing the electrodes is small. In addition, since only the grounded electrode is disposed in the ink chamber, it is possible to prevent the ink and the electrode from being damaged by energization or the like. Further, by covering the electrode disposed in the ink chamber with a protective film, the protection of the electrode can be enhanced.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An ink jet recording apparatus according to an embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a sectional view showing the configuration of an embodiment of the present invention. A print head 1 of this ink jet recording apparatus has a piezo plate 2 whose polarization direction is indicated by an arrow A, an ink supply path forming member 3 and a nozzle plate. 4 and laminated,
By removing a part of the ink supply path forming member 3, an ink chamber 5 and an inlet 7 for introducing the ink 6 into the ink chamber 5 are formed.

The piezo plate 2 has a thickness of, for example, 100 μm to 5 mm, and has a square prism-shaped projection 8 projecting into the ink chamber 5. The projection 8 has a width of, for example, 30 to 250.
The common ground electrode 9 is formed on the inner end face with a size of about 50 μm, a depth of about 50 μm to 1 mm, and a height of about 40 μm to 1 mm. A drive electrode 10 facing the common ground electrode 9 is formed on the outer end surface of the piezo plate 2.
0 is connected to the power supply 12 via the driver 11 and the control unit 13 turns on the driver 11 to
A predetermined voltage is applied between the drive electrode 10 and the common earth electrode 9 so as to vibrate the common earth electrode 9, the drive electrode 10 and the portion of the piezo plate 2 therebetween in the thickness direction of the piezo plate 2. It is composed of That is, the common ground electrode 9, the drive electrode 10 and the portion of the piezo plate 2 between them constitute the piezoelectric vibrator 14.

The thickness of the nozzle plate 4 is, for example, 25 μm.
m to 1 mm, and has a nozzle hole 15. The nozzle hole 15 is formed in each hole such as a circular hole, an elliptical hole, or a square hole having a diameter of about 20 to 200 μm, and communicates the ink chamber 5 with the outside of the nozzle plate 4. The inner portion of the nozzle hole 15, that is, the portion on the ink chamber 5 side is formed as an outer tapered hole in order to smoothly concentrate the ink ejected from the ink chamber 5.

In front of the nozzle hole 15 (upper side in the figure),
For example, the recording paper 16 is supplied to a position separated by a gap of about 0.1 to 1 mm, and a back electrode 17 is provided so as to be in contact with the back of the recording paper 16. This back electrode 17 is connected to another power supply 19 via a switch 18 and
When the switch 18 is turned on by the switch 3, a predetermined voltage is applied between the common earth electrode 9 and the back electrode 17. Thereby, an electrostatic field is formed between the common ground electrode 9 and the back electrode 17, and
The charged ink 6 in contact with the common ground electrode 9 is electrostatically attracted to the recording paper 16. That is, the common ground electrode 9, the back electrode 17, the switch 18, and the power supply 19 constitute an electrostatic field forming unit 20 that applies electrostatic energy for electrostatically attracting the ink 6 from the ink chamber 5 toward the recording paper 16.

The cross-sectional area of the passage of the inlet 7 is set to 90% or less of the minimum cross-sectional area of the nozzle hole 15 to prevent the backflow of the ink 6. When the driver 11 is turned on by the control unit 13 and a single or continuous pulse voltage is applied to the piezoelectric vibrator 14, the piezoelectric vibrator 14 vibrates, whereby the ink 6 is pushed out from the nozzle hole 15 toward the recording paper 16. , For example, as shown in FIG.
An ink meniscus Im is formed.

Further, when the switch 18 is turned on by the control unit 13 and an electric field is formed between the common ground electrode 9 and the back electrode 17 by the electrostatic field forming means 20, the ink meniscus Im is moved by the electrostatic attraction force to the recording paper 16. For example, as shown in FIG. 3, an ink drop Id is formed, and the ink droplet Id flies toward the recording paper 16. The ink 6 that has reached the recording paper 16 adheres to the recording paper 16 and is fixed.

The control section 13 is provided with the electrostatic field forming means 2 first.
0 may be operated, and the piezoelectric vibrator 14 may be operated during the operation. The control unit 13
May be configured so that the operation of the piezoelectric vibrator 14 and the operation of the electrostatic field forming means 20 are started simultaneously and ended simultaneously. Further, one of the switch 18 and the driver 11 may be always turned on, and the other may be turned on when necessary.

That is, the start timing and the end timing of the application of the vibration energy and the application of the electrostatic energy do not always need to coincide, but it is necessary that at least the vibration energy and the electrostatic energy are applied in a superimposed manner. When the vibration energy is lacking, the ink 6 does not fly toward the recording paper 16 because the force for pushing out the ink 6 does not act, and when the electrostatic energy is lacking, the ink 6 is electrostatically attracted toward the recording paper 16. Again, the ink 6 does not fly toward the recording paper 16 because of insufficient power.

Therefore, drop-on-demand is possible, and recycling of the ink 6 becomes unnecessary. Since the common earth electrode 9 is in contact with the ink 6, when the electrostatic field forming means 20 is operated, an effect of injecting electric charge into the ink 6 is generated depending on the resistance value of the ink 6, and the ink 6
Are easily electrostatically attracted to the recording paper 16. Therefore, the common ground electrode 9 and the back electrode 17 of the
Can be reduced.

The vibration energy of the piezoelectric vibrator 14 and the electrostatic energy of the electrostatic field forming means 20 complement each other, and the electric power supplied to each of them is smaller than when the ink 6 is caused to fly by each energy alone. It may be less. As a result, a change in the volume of the ink chamber 3 due to the vibration of the piezoelectric vibrator 14 can be reduced. Therefore, the size of the piezoelectric vibrator 14 can be reduced, and the print head 1 can be made compact and compact. The voltage applied to the means 20 can be reduced.

When a multi-nozzle is used, the size of the piezoelectric vibrator 14 can be reduced as described above, and the vibration wave hardly spreads to the adjacent nozzle holes. Since the electrostatic repulsion and the discharge are hardly generated between the adjacent common earth electrodes 9 of the electrostatic field forming means 20, the interval between the common earth electrodes 9 can be narrowed. Therefore, the multi-nozzle can be easily formed, and the print head 1 can be configured to be small and compact.

Further, in the case of using a multi-nozzle, electrostatic repulsion or discharge is hardly generated between the adjacent common earth electrodes 9, so that the division driving is not required, and the recording speed can be increased. In addition, since the common ground electrode 9 is also used as the ground electrode of the piezoelectric vibrator 14 and the ground electrode of the electrostatic field forming means 20, the configuration of the print head 1 is simplified, and the print head 1 can be reduced in size and size. In addition, it can be made compact.

FIG. 4 is a sectional view showing the structure of another embodiment of the present invention. In a print head 101 of this ink jet recording apparatus, an ink supply path forming member 103 and a nozzle plate 104 are integrally formed, and a polarization direction is formed. Are stacked on the piezo plate 102 in the direction indicated by the arrow B. In addition, drive electrode 1
10 and the common ground electrode 109 are formed on both lateral sides of the convex portion 108 of the piezo plate 102, the drive electrode 110 contacts one side wall surface 105a of the ink chamber 105, and the common ground electrode 109 is connected to the other side. The protrusion 108 is arranged at a position spaced from the wall surface 105b at an appropriate distance.

In FIG. 4, reference numeral 107 denotes an ink chamber 1
Inlet for introducing ink 106 into 05, 11
4 is a piezoelectric vibrator, 116 is a recording paper, 117 is a back electrode,
Numeral 120 indicates an electrostatic field forming means. The operation of this embodiment is essentially the same as that of the above-described embodiment except that the polarization direction of the piezoelectric vibrator 114 is the horizontal direction in the drawing. can get.

FIGS. 5 to 8 show still another embodiment of the present invention. FIG. 5 is a front view, FIG. 6 is a sectional side view, FIG. 7 is a plan view thereof, and FIG. Is a plan view of the part. The print head 201 of this ink jet recording apparatus has a base plate 20 made of a glass plate having a thickness of 1.5 mm, a front-rear length of 60 mm, and a lateral width of about 40 mm.
A piezo plate 202 having a thickness of about 1 mm, a front-rear length of about 24 mm, and a lateral width of about 40 mm is placed on the front portion of 1a.

As shown in FIG. 9, the piezo plate 202
After the resist r is applied to the upper surface of the piezo plate 202 on the flat plate (a), a plurality of (for example, eight) projections 208 are formed by grooving with, for example, a dicing saw (b), and thereafter, For example, the electrode metal m is adhered by oblique vapor deposition (c), and the resist r is peeled off by etching (the etchant penetrates in a direction perpendicular to the plane of the drawing), so that the common earth electrode 209 and the drive electrode 210 are separated. The provided piezoelectric vibrator 214 is formed (d). Further, thereafter, the plurality of grooves 20 corresponding to the ink chambers 205, respectively.
5a formed thickness 1mm, front and rear length 9mm, left and right width 1
The adhesive b is applied to the convex surface of the upper lid 201b made of a glass plate of about 0 mm, and the upper lid 201b is placed on the front portion of the piezo plate 202 so that the convex portion 208 of the piezo plate 202 projects into the groove 205a of the upper lid 201b. The adhesive b is hardened by superposition (e) and baking (f).

The width of each projection 208 of the piezo plate 202 is, for example, 43 μm, and the pitch of each depression 208 is, for example, 83 μm.
μm, and the width of the groove between each recess 208 is 4 μm.
0 μm. The depth of the groove between the projections 208 is, for example, 100 μm. As shown in FIGS. 6 and 7,
On the piezo plate 202, further, on the rear side of the upper lid 201b, there are placed three weirs 201c made of glass plates having a thickness of, for example, 1 mm, a front-rear length of 7 mm, and a lateral width of about 10 mm. An ink storage chamber 221 communicating with the ink chamber 205 is formed between the ink storage chamber 221 and the ink storage chamber 201c. The length of the ink storage chamber 221 is, for example, 5 mm, and the width is 10 mm. The upper surface of the ink storage chamber 221 is, for example, 1 mm thick, 7 mm long, 9 m wide.
m, covered with an ink lid 201d made of a glass plate,
The ink 206 is supplied from outside via the ink supply pipe 225.

On the upper surface of the piezo plate 202, at the same time as the common ground electrode 209 and the drive electrode 210, a lead wire continuous to these electrodes is formed by aluminum evaporation. As shown in FIG. 6, this lead wire is formed on the rear portion of the base plate 201a. Is connected via a wire 224 to a wiring 223 of a printed circuit board 222 mounted on the device. Each drive electrode 210 is connected to a power supply via an individual driver, and the control unit drives the individual driver to turn on / off each drive electrode 210 individually.

The printed circuit board 222 is made of glass 2
Wiring 223 is formed on 22a, and is formed, for example, to have a thickness of about 1 mm, a front-rear length of about 30 mm, and a lateral width of about 40 mm. A nozzle plate 204 made of, for example, a polyimide resin film is adhered to the front surfaces of the piezo plate 202 and the base plate 201a. The nozzle plate 204 has nozzle holes 215 corresponding to the respective ink chambers 205.

Other configurations are the same as those of the above embodiments, such as the common ground electrode 209 also serving as the ground electrode of the electrostatic field forming means 220. In this embodiment, the control unit drives the individual driver in accordance with the print data to individually turn on and off each of the drive electrodes 210, so that the piezoelectric vibrator 214 of each ink chamber 205 is formed.
Are individually driven to apply vibration energy to the ink 206 in the corresponding ink chamber 205, and
An ink meniscus swelling from 15 is formed. Then, the ink 206 is electrostatically attracted toward the recording paper by an electric field formed between the common ground electrode 209 and the recording paper (not shown), and flies toward the recording paper. Then, the record corresponding to the print data is reproduced on the recording paper.

FIGS. 10 and 11 show still another embodiment of the present invention. In the print head 301 of this embodiment, a slit 315 is continuous with the ink chamber 305 instead of the nozzle hole 15 (115, 215). Formed, piezo cylinder 314
Is also used as a feed roller for sending the ink 306 to the slit 315. The piezo cylinder 314 and the ink 3
The drive electrode 321 also serving as an electrode for injecting electric charges into the transistor 06 and the common ground electrode 322 constitute a piezoelectric vibrator 320. The common ground electrode 322 also serves as an electrode for electrostatic field forming means. When an electric line of force generated by applying a voltage between the drive electrode 321 and the common earth electrode passes through the inside of the piezoelectric vibrator 314 in the axial direction, the piezoelectric vibrator 314 passes through the electric line of electric force. The vicinity of the portion expands and contracts in the radial direction, whereby the ink 306 is partially provided with vibration energy, and the ink 306 at that portion flies toward the recording paper in a state where an electric field is formed by the electrostatic field forming means. It is configured as follows.

The other structure is the same as that of the above-described embodiment, and the operation is the same as that of the above-described embodiment except that printing control is performed by individually controlling electrostatic energy in dot units. Yes, a similar effect can be obtained. In addition, by using the slit 315, the ink 306 can be formed.
Of the piezoelectric vibrator 314.
By providing a feed roller composed of
06 replenishment ability is increased, and the recording frequency can be further increased to increase the recording speed.

FIG. 12 shows another embodiment of the present invention. In this embodiment, the piezoelectric vibrator 414 includes the nozzle 401.
And a nozzle hole 415 is formed at the center thereof. A recording paper 416 and a bias platen roller 417 as a back electrode of the electrostatic field forming means 420 are disposed in front of the nozzle hole 415.
Reference numeral 17 is connected to a power supply 419 via a switch circuit 418.

The common ground electrode 40 of the piezoelectric vibrator 414
Reference numeral 7 contacts the ink chamber 405 in the nozzle 401 via the protective film 421, and the drive electrode 410 is formed on the tip end surface of the nozzle 401. The drive electrode 410 is connected to a power supply 412 via a driver 411. Reference numeral 406 denotes ink.
Other configurations, operations and effects of this embodiment are the same as those of the above-described embodiment.

Incidentally, the ink chambers 5 (10
5, 205, 305, 405), it is possible to form the ink chamber with a number of small holes (fine bores) formed in an endless or endless band. In this case, ink clogging is possible. Can be prevented, and the resolution or recording density and the recording speed can be increased by narrowing the pitch of the small holes.

The electrostatic field forming means 20 (120, 22)
0, 320, 420) are the back electrodes 17 (117, 41).
Instead of 7), it is possible to use a photoconductor on which an electrostatic latent image is formed. In this case, the driver 11 (411)
Alternatively, an individual driver is not required, and an electrostatic latent image may be recorded on the photoconductor using an optical head using an LCD, a laser beam exposure head, an LED, a PLZT, or the like.

The ink 6 (106, 206) used in each of the above embodiments is not particularly limited, and for example, a pigment-dispersed ink can be used. The pigment-dispersed ink includes 10 to 80% by weight of a dispersion medium, 3 to 30% by weight of a pigment, 20% by weight or less of a dispersant, 0.2 to 30% by weight of a resin, and, if necessary, a masking agent and a fragrance. , A bleeding inhibitor, a rust inhibitor, a surfactant, a lubricant, and the like, and a pigment or other component dispersed or dissolved in a dispersion medium by stirring and mixing.

Examples of the dispersion medium include water, alcohols, ketones or keto alcohols, alkanolamines, amides, ethers, esters, lower alkyl monoethers or lower alkyl diethers derived from alkylene glycol, and the like. An organic solvent such as a nitrogen cyclic compound is used. The alcohols include methyl alcohol, ethyl alcohol, n-propyl alcohol, i
so-propyl alcohol, n-butyl alcohol, s
monohydric alcohols such as ec-butyl alcohol, tert-butyl alcohol, iso-butyl alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol, ethylene glycol, diethylene glycol,
Representative examples include polyhydric alcohols such as triethylene glycol, propylene glycol natraethylene glycol, polyethylene glycol, glycerin, 1.2.6-hexanetrichol, and thiodiglycol.

As ketones or keto alcohols,
Acetone, methyl ethyl ketone, diacetone alcohol and the like are mentioned as examples, and as alkanolamines, monoethanolamine, jetanolamine, triethanolamine and the like are mentioned as examples. Examples of the amides include dimethylformamide and dimethylacetamide.Examples of the ethers include tetrahydrofuran and dioxane.Examples of the esters include ethyl acetate, methyl benzoate, ethyl lactate, and ethylene carbonate. And the like.

The lower alkyl monoethers derived from alkylene glycols include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether and the like. Examples thereof include lower alkyl diethers derived from alkylene glycols, such as diethylene glycol dimethyl ether and diethylene glycol diethyl ether.

As a nitrogen-containing cyclic compound, hirolidone is typical. Of these many dispersion media, it is recommended to use polyhydric alcohols or alkylethyls of polyhydric alcohols in order to improve various properties required for the ink 2. Particularly, diethylene glycol is preferred. It is recommended to use polyhydric alcohols such as.

The content of the dispersion medium is generally 10 to 80% by weight based on the total weight of the ink.
20-70% to reduce the temperature dependence of physical properties
Is preferable. As the pigment, various organic or inorganic pigments, including conventionally known pigments, can be applied to all. These organic or inorganic pigments can be chemically classified, but organic pigments are classified into insoluble dyes and lakes, and inorganic pigments are classified into natural minerals and artificial inorganic compounds.

If the organic pigments are chemically classified, they may be azo-based,
It is classified into phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigo-based, thioindigo-based, belinone-based, berylen-based, and isoindolenone-based. Examples of insoluble dyes include yellow pigments such as Hansa Yellow and Benzin Yellow, dark pigments such as Indazlen Orange and the like, para red, thioindigo red,
Typical examples thereof include red pigments such as tolindigo red, purple pigments such as indastan bordeaux and toluidine maroon, blue pigments such as indathrene blue RS and phthalocyanine blue, and green pigments such as phthalocyanine green.

The lake absorbs a water-soluble dye into an extender such as alumina, baryte, clay, etc., and then forms barium chloride, lead acetate, aluminum sulfate, tannic acid, sodium phosphate, phosphorus tungstate, phosphorus molybdate, etc. Is converted into insoluble by adding a metal circle as a precipitant, most of which is from a basic dye, followed by most of an azo dye.

As the rake, yellow pigments such as Auramine Lake, Fast Light Yellow 3G, etc., orange-color pigments such as Verscia Orange, Pigment Scarlet 3G, etc., Lysole Red, Lake Red, Eosin Lake, Rhodamine Lake, etc. Red pigments, purple pigments such as methyl violet lake, blue pigments such as Victoria Blue Lake and Peacock Blue Lake, and green pigments such as Acid Green Lake and Malachite Green Lake.

If the inorganic pigments are chemically classified, pigments such as titanium oxide, lead-based, cadmium-based, iron oxide-based, and carbon black can be mentioned. However, inorganic pigments are generally white pigments, yellow pigments, red pigments,
It is classified into purple pigment, blue pigment, green pigment, black pigment and the like. White pigments include zinc white (zinc white, ZnO), lithopone (BaSO ₄ + ZnS), titanium white (titanium oxide, TiO ₂ ),
Lead white (2PbCO ₃ · Pb (OH) ₂ ), barite (BaSO ₄ ), chalk (chalk, stone powder, CaCO ₃ ), chalk (CaCO ₃ ), clay (kaolin, white clay, Al ₂ O ₃ · 2SiO ₂ · 2H ₂ O) is a typical example.

As the yellow pigment, there may be used graphite (chrome yellow, PbCr
O_Four), Zinc yellow (ZnCrO_Four), Cadmium yellow (cadmium
Raw, CdS), antimony yellow (Naples yellow, Pb (SbO_Three)
_Two), Loess (Fe_TwoO_Three・ XAl_TwoO_Three・ YSiO_Two ), Yellow iron oxide
(Mars yellow, ferrit yellow, Fe _TwoO_Three・ NH_TwoO) etc. are typical
It is. As a red pigment, red iron (Fe_TwoO_Three), Lead Tan
(Komeitan, Pb_ThreeO_Four), Vermilion (cinnabar, HgS), cadmium red
(Selenium red, CdS.CdSe) and the like are typical.

As purple pigments, Mars purple (Fe ₂ O ₃ ),
Manganese purple (Nuremberg purple, (NH ₄ ) Mn (PO ₄ ) ₂ ), cobalt purple (Co ₃ (PO ₄ ) ₂ , Co ₃ (AsO ₄ ) ₂ ) and the like are typical. Blue pigments include ultramarine (ultramarine, alumino-silicate containing sulfur), navy blue (Berlin blue, Millory blue, Fe (NH ₄ ) [Fe (CN) ₆ ], FeK [Fe (C
N) ₆ ]) and cobalt blue (CaO.xAl ₂ O ₃ ) are typical.

Green pigments include chrome green (a mixture of graphite and navy blue mixed with barite), chromium oxide (Cr ₂ O ₃ ), emerald green (Cu (CH ₃ CO ₂ ) ₂ .3Cu (As
O ₃ ) ₂ ), cobalt green (CoO.10ZnO), natural green (CuCO ₃
・ Cu (OH) ₂ ) is typical. The black pigment is generally called carbon black, and typical examples thereof include channel black, furnace black, acetylene black, anthracene black, oil smoke, pine smoke, graphite, and the like.

These pigments have a particle size in the ink 2 of about several hundred millimicrons to about several microns, and are preferably aqueous pastes. The amount of the pigment incorporated in the ink 2 is in the range of 3 to 30% by weight based on the total amount of the ink 2 in consideration of its coloring power and the effect on the viscosity of the recording liquid. As the dispersant, a nonionic, anionic or cationic surfactant is used.

Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyalkyl phenyl ether, polyoxyethylene fatty acid ester, and polyoxyethylene polyoxypropylene block copolymer. Examples of the anionic surfactant include higher alcohol sulfates, sulfated esters of polyoxyethylene adducts, and alkyl sulfates of fatty acid alkylamides.

Examples of the cationic surfactant include a higher alkyl ammonium halide. The amount of the dispersant is usually in the range of 20% by weight or less, preferably 15% by weight or less based on the total amount of the ink 2. The resin added to the dispersion medium is dissolved and compounded to enhance the dispersibility of the pigment and to enhance the adhesion to the recording paper 8.

The resin is not particularly limited as long as it is soluble in the dispersion medium. Vinyl resins, hydrocarbon resins, phenol resins, xylene resins, ketone resins, alkyd resins, polyamide resins, polyester resins, and maleic resins One or two or more of natural resins and synthetic resins such as cellulose resin, rosin resin, gelatin, shellac and the like are used.

Representative vinyl resins include polymethacrylate resin, polyacrylate resin, acrylate-acrylate copolymer resin,
Polyvinyl pyrrolidone, polypinyl butyral and the like can be mentioned. The amount of the resin is usually 0.2 to 30% by weight based on the total amount of the ink 2. If the amount of the resin is less than this range, the dispersion stability of the pigment in the ink 2 is lowered, and the fixability to the recording paper 8 is also lowered. It is more preferable to set the compounding amount of the resin in the range of 0.3 to 10% by weight based on the total amount of the ink 2 in order to enhance the dispersibility of the pigment and the adhesion to the recording paper 8.

As a method of mixing and stirring the components of the ink 2, a known method using a homomixer, a ball mill, a homogenizer, a sand mill, a roll mill, or the like may be employed. Actually, inks having the compositions of Samples 1 to 4 shown in Table 1 were prepared and used in Examples.

[0055]

[Table 1]

These inks 2 have a viscosity at room temperature of ³ to ¹⁰⁰ cp, an electric resistance of 10 ³ to 10 ¹⁰ Ω · cm, a surface tension of 25 to 55 dyne / cm, and are not boiled.
For example, in the state of being heated to about 50 to 170 ° C., viscosity 1～30Cp, electric resistance 10 ³ ~10 ⁹ Ω · cm, the surface tension is 15~35dyne / cm. Then, when attached to a recording medium, advantages such as higher recording density, light resistance, and water resistance and higher fixing speed can be obtained as compared with the conventional dye-dissolved ink.

[0057]

As described above, according to the present invention, the ink is caused to fly by the vibration energy of the piezoelectric vibrator and the electrostatic energy of the electrostatic field forming means. The power supplied to each of them may be smaller than that of.

As a result, the volume change of the ink holding portion due to the vibration of the piezoelectric vibrator can be reduced, the vibration wave hardly spreads to the adjacent nozzle holes, the interval between the nozzle holes can be narrowed, and therefore, the high density multi-nozzle can be obtained. It becomes easier. In addition, the voltage applied to the electrodes corresponding to each nozzle hole or dot of the electrostatic field forming means can be reduced, so that electrostatic repulsion or discharge is less likely to occur between adjacent electrodes, and the interval between the electrodes can be reduced. In addition, it becomes easier to form a multi-nozzle with higher density, and it is not necessary to perform the division driving, so that the recording speed can be increased.

In addition, since one electrode of the piezoelectric vibrator is used also as the electrode of the seal of the electrostatic field forming means, there is an effect that the configuration is simple, easy and inexpensive.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of one embodiment of the present invention at rest.

FIG. 2 is a cross-sectional view of one embodiment of the present invention when applying vibration energy.

FIG. 3 is a cross-sectional view at the time of applying vibration energy and electrostatic energy according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view of another embodiment of the present invention at rest.

FIG. 5 is a front view of still another embodiment of the present invention.

FIG. 6 is a sectional side view of still another embodiment of the present invention.

FIG. 7 is a plan view of still another embodiment of the present invention.

FIG. 8 is a plan view of each component of still another embodiment of the present invention.

FIG. 9 is a flowchart showing a part of a manufacturing procedure according to still another embodiment of the present invention.

FIG. 10 is a sectional view of still another embodiment of the present invention.

FIG. 11 is a front view of still another embodiment of the present invention.

FIG. 12 is a sectional view of another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 5 ink chamber 6 ink 14 piezoelectric vibrator 16 recording paper 20 electrostatic field forming means 105 ink chamber 106 ink 114 piezoelectric vibrator 120 static electric field forming means 205 ink chamber 206 ink 214 piezoelectric vibrator 220 static electric field forming means 305 ink chamber 306 ink 314 Piezoelectric vibrator 320 Electrostatic field forming means 405 Ink chamber 406 Ink 414 Piezoelectric vibrator 416 Recording paper 420 Electrostatic field forming means

Claims (2)

(57) [Claims] An ink chamber for holding ink is provided.
An ink holding unit having a nozzle directed from the ink chamber toward the recording medium; and a first area near the nozzle and facing the ink chamber.
A piezoelectric vibrator including a second region that does not face the ink chamber, a first electrode provided in the first region and grounded, a second electrode provided in the second region, and the nozzle The third provided on the back side of the recording medium
An electrode , connected to the second electrode, and applying a signal voltage to the second electrode.
To form an electric field between the first electrode and the second electrode.
To vibrate the piezoelectric vibrator,
Vibration energy applying hand that gives vibration energy to ink
A step , connected to the third electrode, for applying a voltage to the second electrode;
The electrostatic force between the first electrode and the third electrode
An ink jet recording apparatus characterized by comprising a, a Ru electrostatic field forming means is electrostatically attracted toward the recording medium from the ink holding means formed to ink the field. 2. The first electrode is covered with a protective film.
The ink jet recording according to claim 1, wherein
apparatus.