EP0911164A2 - Aufzeichnungsverfahren unter Benutzung von elektrosensitiven beweglichen Flüssigkeiten und Aufzeichnungsgeräte - Google Patents

Aufzeichnungsverfahren unter Benutzung von elektrosensitiven beweglichen Flüssigkeiten und Aufzeichnungsgeräte Download PDF

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Publication number
EP0911164A2
EP0911164A2 EP19980308685 EP98308685A EP0911164A2 EP 0911164 A2 EP0911164 A2 EP 0911164A2 EP 19980308685 EP19980308685 EP 19980308685 EP 98308685 A EP98308685 A EP 98308685A EP 0911164 A2 EP0911164 A2 EP 0911164A2
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EP
European Patent Office
Prior art keywords
ink
electrodes
electrode
jet
ink composition
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19980308685
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English (en)
French (fr)
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EP0911164A3 (de
Inventor
Jun Takayanagi
Yasufumi Otsubo
Makoto Takayanagi
Shinichi Yokota
Yasunori Imagawa
Kazuya Edamura
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Takayanagi Research Inc
New Technology Management Co Ltd
Shinten Sangyo Co Ltd
Original Assignee
Takayanagi Research Inc
New Technology Management Co Ltd
Shinten Sangyo Co Ltd
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Application filed by Takayanagi Research Inc, New Technology Management Co Ltd, Shinten Sangyo Co Ltd filed Critical Takayanagi Research Inc
Publication of EP0911164A2 publication Critical patent/EP0911164A2/de
Publication of EP0911164A3 publication Critical patent/EP0911164A3/de
Withdrawn legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/015—Ink jet characterised by the jet generation process
    • B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/06—Ink jet characterised by the jet generation process generating single droplets or particles on demand by electric or magnetic field
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/015—Ink jet characterised by the jet generation process
    • B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/06—Ink jet characterised by the jet generation process generating single droplets or particles on demand by electric or magnetic field
    • B41J2002/061—Ejection by electric field of ink or of toner particles contained in ink

Definitions

  • the present invention relates to methods of using ink-jet recording ink compositions containing electro-sensitive movable fluids (also called “Electro-Conjugated Fluids (ECF)” by the present inventors) and to recording apparatuses (e.g., printers) using the ink-jet recording ink compositions.
  • electro-sensitive movable fluids also called “Electro-Conjugated Fluids (ECF)” by the present inventors
  • recording apparatuses e.g., printers
  • the printers are broadly divided into wire dot printers, heat-sensitive transfer printers, ink jet printers and laser printers based on the recording system.
  • the ink jet printers are relatively small and lightweight, and besides they are capable of performing multi-color printing. Therefore, the ink jet printers have been broadly employed.
  • Examples of recording systems adopted in the ink jet printers include a bubble jet system, in which ink is heated to produce bubbles and the ink is jetted by the action of the bubbles, and an ink jet system using a piezo element.
  • a pump chamber needs to be provided per one dot in order to perform ink jetting, and besides the pump chamber must be connected to an ink tank by a capillary in order to prevent back-flow of the ink caused by pressurizing the pump chamber.
  • the pump chamber By the provision of the pump chamber, the structure of the ink jet means becomes complicated. Moreover, agglomeration of ink occasionally takes place in the capillary, and it may be difficult to stably feed ink for a long period of time.
  • ER ink composition having electrorheological (ER) properties such that the composition is increased in its viscosity (the composition becomes non-fluid according to circumstances) when a voltage is applied from the external electric field
  • ER ink composition having electrorheological (ER) properties such that the composition is increased in its viscosity (the composition becomes non-fluid according to circumstances) when a voltage is applied from the external electric field
  • the ER ink composition comprises a dielectric fluid and ER particles dispersed in the fluid.
  • the ink jet mechanism is as follows. When a voltage is applied to the ER ink composition filled between electrodes facing each other, the ER particles dispersed in the ER ink composition are polarized by the action of an electric field generated between the electrodes. By virtue of the electrostatic attractive force based on the polarization, the ER particles are coordination linked to each other in the direction of the electric field and thereby become a resistance to the external shear flow. This resistance stops jetting of the ink composition (off-state is formed).
  • the ink composition when no voltage is applied, the ink composition is allowed to exhibit fluidity inherent in the composition, and due to the external shear flow, the ink composition is jetted (on-state is formed). Thus, the jetting of the ink composition is controlled.
  • the ER effect is utilized as a resistance to the external shear flow which is produced by the coordination linkage of the ER particles in the ER ink composition upon application of a voltage. That is, the ER effect is utilized as a source of generating a force to allow the ER particles to functions as a stop valve for controlling jetting of the ER ink composition.
  • ER particles for use in the conventional ER ink composition there have been proposed particles comprising cores of a polymer material having a specific gravity of not more than 1.2 and a hydrophilic compound with which the cores are covered (see Japanese Patent Laid-Open Publication No. 162494/1991).
  • An ER ink composition using such particles is also known (see Japanese Patent Laid-Open Publication No. 257485/1992).
  • the ER ink composition In a printer using the conventional ER ink composition, the ER ink composition is always under pressure (in the external shear flow state), and in order to allow the ER particles in the ER ink composition under pressure to function as a stop valve, a voltage is applied to the ER ink composition to coordination link the ER particles to one another. In the use of the printer, therefore, it is necessary to continuously apply a voltage to the ER ink composition except an extremely short period of time for jetting the ER ink composition. Further, in order to coordination link the ER particles and thereby allow them to have a sufficient function as a stop valve, a considerably high voltage must be applied.
  • the voltage applied to one nozzle is high as described above. Therefore, the number of the nozzles employable for one printer is limited, and the limited number of nozzles must be moved to perform recording. Further, the nozzles are driven by a driving means such as a motor, and hence a problem of noise of the driving means takes place.
  • the ER ink composition contains the ER particles.
  • the ER particles When the ER ink composition is jetted, the ER particles are brought into contact with the electrode to which a voltage is applied and which is provided on the ink jet nozzle, and with the wall of the orifice.
  • the ER particles are inorganic particles as described above, and therefore the inner surface of the nozzle wall is considerably abraded by the contact with the ER particles. If the abrasion powder is introduced into the ER ink composition, ER properties of the ER ink composition are altered, and this may cause extraordinary current between the electrodes.
  • the ER ink composition is a dispersion of the ER particles in a dielectric fluid, and the ER particles have a problem of dispersion stability in the ER ink composition. That is, when the ER ink composition is stored for a long period of time, the ER particles may be sedimented. In the ER ink composition containing the sedimented ER particles, the function as a stop valve due to the coordination linkage of the ER particles is not sufficiently exhibited even if a voltage is applied.
  • the invention provides a method of using an ink-jet recording ink composition, said method comprising:
  • the method of using an ink-jet recording ink composition preferably comprises:
  • the method of using an ink-jet recording ink composition preferably comprises:
  • the method of using an ink-jet recording ink composition preferably comprises:
  • the method of using an ink-jet recording ink composition preferably comprises:
  • the invention provides a recording apparatus of printing mechanism, including an ink jet means having a hole through which an ink-jet recording ink composition is jetted correspondingly to printing signals.
  • the recording apparatus of the invention is a recording apparatus of printing mechanism, including an ink jet means having a hole through which an ink-jet recording ink composition is jetted correspondingly to printing signals,
  • the recording apparatus preferably comprises an ink jet means having a hole through which an ink-jet recording ink composition is jetted correspondingly to printing signals, correspondingly to printing signals,
  • the recording apparatus preferably comprises an ink jet means having a hole through which an ink-jet recording ink composition is jetted correspondingly to printing signals,
  • the recording apparatus preferably comprises an ink jet means having a hole through which an ink-jet recording ink composition is jetted correspondingly to printing signals, correspondingly to printing signals,
  • the recording apparatus preferably comprises an ink jet means having a hole through which an ink-jet recording ink composition is jetted correspondingly to printing signals, correspondingly to printing signals,
  • the ink-jet recording ink composition comprises an electro-sensitive movable fluid, which is capable of producing a jet flow according to the applied voltage, and a colorant dissolved or dispersed in the fluid.
  • electro-sensitive movable fluid When a certain dielectric fluid (i.e., "electro-sensitive movable fluid” referred to herein) is subjected to an electric field, an electric force is generated in the fluid owing to the ununiformity of electric conductivity and dielectric constant.
  • the Coulomb force acting on free charge dominates rather than the dielectrophoretic force.
  • This Coulomb force causes hydrodynamic instability, resulting in occurrence of convection of the electro-sensitive movable fluid or a secondary motion of the fluid. These phenomena are called “electrohydrodynamic (EHD) effects".
  • the present inventors have found that an ink composition prepared by dissolving or dispersing a colorant in the electro-sensitive movable fluid can be vigorously jetted from a nozzle by applying a voltage to the composition.
  • the present inventors consider that the jet phenomenon of the ink composition is owing to the EHD effects. Utilization of the EHD effects in the ink-jet recording type printers has been never known hitherto.
  • the present inventors consider that the motion of the ink-jet recording ink composition in the present invention is probably-by virtue of the EHD effects, but they do not conclude that the phenomenon occurring in the invention is owing to the "EHD effects".
  • Fig. 1 is a view to explain jetting principles of an ink composition for use in the present invention.
  • Fig. 2 is a view to explain jetting principles of an ink composition for use in the present invention.
  • Fig. 3 is a view schematically showing an embodiment of the recording apparatus according to the present invention.
  • Fig. 4 is a graph showing a relation between a conductivity ⁇ and a viscosity ⁇ of an electro-sensitive movable fluid at 25 °C.
  • Fig. 5 is a view showing a height of jetted dibutyl decanedioate (DBD) and a current between the electrodes given when the applied voltage is changed in the range of 0 to 12 kV.
  • DBD jetted dibutyl decanedioate
  • Figs. 6(A), 6(B) and 6(C) are each a view showing another embodiment of the electrode employable in the present invention.
  • Figs. 7(A), 7(B) and 7(C) are each a view schematically showing plural nozzles which are together used to form one dot.
  • Figs. 8(a), 8(b), 8(c), 8(d) and 8(e) and Fig. 9 are each a view to explain a method of applying a voltage to a recording apparatus using an ink attraction electrode.
  • Fig. 10, Fig. 11, Fig. 12, Fig. 13 and Fig. 24 are each a view schematically showing a nozzle of a recording apparatus including a gate electrode.
  • Fig. 14 is a view schematically showing deviation of a jet line of an ink composition.
  • Fig. 15, Fig. 16, Fig. 17 and Fig. 18 are each a view showing deviation correction of a jet line of an ink composition by the use of plural nozzles.
  • Fig. 19, Fig. 20, Fig. 21 and Fig. 22 are each a view showing another embodiment of the source electrode used in the recording apparatus of the present invention.
  • Fig. 23 is a view schematically showing a nozzle used in Example 10.
  • Fig. 25 is a view schematically showing the other embodiment of the recording apparatus according to the present invention.
  • the ink-jet recording ink composition for use in the invention comprises an electro-sensitive movable fluid, which is capable of forming a jet flow between the electrodes correspondingly to the applied voltage, and a colorant dissolved or dispersed in the fluid (, or which is colored).
  • the electro-sensitive movable fluid used herein is an organic compound which is liquid at working temperatures at which a jet flow of the compound can be produced between the electrodes correspondingly to the applied voltage.
  • This organic compound is substantially dielectric.
  • the electro-sensitive movable fluid for the ink-jet recording ink composition employable in the invention is preferably a compound or a mixture each having the following specific conductivity and the following specific viscosity at the working temperature.
  • the dielectric fluids including the above compounds are measured under the conditions of an electric field intensity of 2 kVmm -1 and a temperature of 25 °C, the dielectric fluids are distributed as shown in Fig. 4.
  • the compound used as the electro-sensitive movable fluid in the ink composition for use in the invention is preferably a compound having, at its working temperature, a conductivity ⁇ and a viscosity ⁇ located on or inside a triangle in a graph (Fig. 4) wherein the conductivity ⁇ is plotted as abscissa and the viscosity ⁇ is plotted as ordinate, said triangle having the following points P, Q and R as vertexes.
  • the mixture is preferably such a mixture as adjusted to have a conductivity ⁇ and a viscosity ⁇ located inside the above triangle.
  • the points P 0 , Q 0 and R 0 are particularly preferable points as the vertexes of the triangle wherein the electro-sensitive movable fluid of the invention is located.
  • the conductivity and the viscosity of the mixture are made to be located on or inside the triangle defined by the points P, Q and R shown in Fig. 4, whereby the mixture can be preferably used in the invention.
  • a mixture of the compounds can be favorably used as the electro-sensitive movable fluid in the invention, as far as the conductivity and the viscosity of the mixture are within the above range, respectively.
  • the requisite of the electro-sensitive movable fluid is that the movable fluid has the above-defined conductivity and viscosity at the temperature at which the ink composition is used. That is, even the compounds having a conductivity and a viscosity out of the above range at 25 °C are employable as the electro-sensitive movable fluids, as far as the conductivity and the viscosity of the compounds are within the above range at the working temperature of the ink composition when the ink composition is used under heating.
  • a colorant is dissolved or dispersed in the electro-sensitive movable fluid.
  • Colorants generally include dyes and pigments, and in the invention, conventional dyes and pigments are both employable.
  • dyes employable as the colorants in the invention include azo dyes, anthraquinone dyes, indigoid dyes, phthalocyanine dyes, carbonium ion dyes, nitro dyes, quinacrine dyes and naphthoquinone dyes.
  • pigments employable as the colorants in the invention include inorganic pigments and organic pigments.
  • the inorganic pigments include white pigments, such as zinc oxide, lithopone and titanium oxide; yellow pigments, such as chromium yellow, cadmium yellow and nickel titanium yellow; red pigments, such as red iron oxide, cadmium red and molybdenum orange; blue pigments, such as Prussian blue and ultramarine blue; and carbon black.
  • white pigments such as zinc oxide, lithopone and titanium oxide
  • yellow pigments such as chromium yellow, cadmium yellow and nickel titanium yellow
  • red pigments such as red iron oxide, cadmium red and molybdenum orange
  • blue pigments such as Prussian blue and ultramarine blue
  • carbon black cyan pigments
  • phthalocyanine pigments such as chromium yellow, cadmium yellow and nickel titanium yellow
  • red pigments such as red iron oxide, cadmium red and molybdenum orange
  • blue pigments such as Prussian blue and ultramarine blue
  • carbon black such as Prussian blue and ultramarine blue
  • the colorants mentioned above can be used singly or in combination.
  • the content of the colorant in the ink composition can be appropriately determined.
  • additives such as stabilizer, dispersant, surface active agent, viscosity increasing agent, rheological property adjusting agent, ink fixation improver, volatility adjusting agent, antiseptic agent, mildew-proofing agent, color tone adjusting agent and gloss adjusting agent, can be generally added according to necessity.
  • the stabilizer employable herein is, for example, an ultraviolet light absorber.
  • the ultraviolet light absorbers include benzophenone derivatives, such as 2,2'-dihydroxy-4-methoxybenzophenone, benzotriazole derivatives, substituted acrylonitrile derivatives, aromatic ester derivatives and triazine derivatives.
  • high-molecular dispersants and the surface active agents employable herein include anionic surface active agents, such as alkyl sulfonate, alkylaryl sulfonate and sulfosuccinic ester; cationic surface active agents, such as tertiary amine salt, quaternary ammonium salt, tertiary sulfonium salt and alkylpyridinium salt; and nonionic surface active agents, such as polyhydric alcohol derivatives.
  • anionic surface active agents such as alkyl sulfonate, alkylaryl sulfonate and sulfosuccinic ester
  • cationic surface active agents such as tertiary amine salt, quaternary ammonium salt, tertiary sulfonium salt and alkylpyridinium salt
  • nonionic surface active agents such as polyhydric alcohol derivatives.
  • the additives can be added in amounts not detrimental to the properties of the ink composition.
  • the additived are used in amounts of not more than 30 % by weight based on the total of the electro-sensitive movable fluid and the colorant.
  • the ink-jet recording ink composition for use in the invention can be prepared by mixing the electro-sensitive movable fluid, the colorant (dyes or pigments), and if necessary, additives.
  • the ink composition can be jetted from the ink jet means utilizing such properties of the electro-sensitive movable fluid that a jet flow of the fluid is produced when a voltage is applied to the fluid.
  • Fig. 1 and Fig. 2 are each a view to explain jetting principles of the ink composition.
  • a needle electrode is used as the electrode
  • a linear electrode is used as the electrode.
  • a nozzle base 14 consisting of a substrate 10 made of an insulating material (e.g., plastic) and a conductive metal 12 (e.g., gold, silver or copper) adhesion bonded to the substrate is prepared.
  • the nozzle base 14 is provided with a through-hole 15.
  • the through-hole 15 shown in Fig. 1 and Fig. 2 is in the form of a truncated cone (taper), in which the bottom diameter is larger than the top diameter (diameter on the metal 12 side).
  • the through-hole 15 is connected to a through-hole of a nozzle-like electrode 16 (ink jet electrode) provided on the conductive metal 12.
  • the diameter of the through-hole of the nozzle-like electrode 16 is equal to the top diameter of the truncated conical through-hole.
  • the nozzle-like electrode 16 serves not only as an electrode but also as a jet guide of the ink composition from the through-hole 15.
  • An additional ink jet guide means may be provided at the upper part of the nozzle-like electrode 16 to control distance, direction, diffusion, etc. of the jetted ink composition.
  • a source electrode is arranged in the vicinity of the bottom of the through-hole 15, a source electrode is arranged.
  • a needle electrode 17 is arranged in Fig. 1
  • a linear electrode 18 is arranged in Fig. 2.
  • the needle electrode is described below in detail, but for example, a linear electrode may be provided concentrically with the ink jet electrode so that the bottom end of the ink jet electrode is surrounded with the linear electrode, or a network electrode formed of plural linear electrodes may be provided in such a manner that the bottom end of the ink jet electrode is covered with the network electrode. Details of various source electrodes other than the needle electrode will be described later.
  • the needle electrode 17 is arranged in such a manner that the tip thereof partly enters the through-hole 15 at almost the center of the through-hole. However, an ununiform electric field can be generated even if the tip of the needle electrode 17 does not enter the through-hole.
  • a linear electrode 18 extended along the diameter of the through-hole is arranged on the bottom end side of the through-hole 15.
  • the needle electrode 17 or the linear electrode 18 is connected to a controller 20, and also the nozzle-like electrode 16, i.e., ink jet electrode, is connected to the controller 20.
  • a direct-current-voltage is applied between the needle electrode 17 and the nozzle-like electrode 16 or between the linear electrode 18 and the nozzle-like electrode 16.
  • the ink jet means having the above structure is arranged on the liquid level of the ink composition.
  • the nozzle base 14 is inclined (by 20° in these figures) to the liquid level of the ink composition to facilitate measurement of a jet height (H) of the ink composition.
  • a voltage such as a pulse voltage, a rectangular voltage or a continuous voltage is applied between the needle electrode 17 and the nozzle-like electrode 16 or between the linear electrode 18 and the nozzle-like electrode 16 from the controller 20, a jet flow of the ink composition is produced in the direction of the needle electrode 17 or the linear electrode 18 to the nozzle-like electrode 16, and the ink composition is jetted from the tip of the through-hole of the nozzle-like electrode 16.
  • the jet height (H) of the ink composition is determined according to the applied voltage and the type of the electro-sensitive movable fluid for forming the ink composition, provided that the same nozzle is used.
  • Fig. 5 shows a jet height of dibutyl decanedioate (DBD) and a current between electrodes given when the voltage applied between the nozzle-like electrode 16 having a through-hole top diameter of 1.5 mm and the needle electrode is changed in the range of 0 to 12 kV.
  • DBD dibutyl decanedioate
  • the ink jet electrode is explained herein by exemplifying the nozzle-like electrode, the ink jet electrode is not limited to an electrode in the cylindrical shape such as a nozzle, and as a matter of course, ink jet electrodes of variously modified shapes, e.g., ink jet electrode consisting of two flat plates facing each other, are available.
  • the method of using the ink composition according to the invention is a method wherein the ink composition comprising the electro-sensitive movable fluid (e.g., DBD) and the colorant dissolved or dispersed in the fluid is jetted from the ink jet means utilizing such properties of the electro-sensitive movable fluid that a jet flow of the fluid is produced by application of a voltage.
  • the electro-sensitive movable fluid e.g., DBD
  • the voltage applied between the electrodes is a direct-current-voltage producing a potential difference of usually 50 V to 30 kV, preferably 100 V to 15 kV.
  • a potential difference of usually 50 V to 30 kV, preferably 100 V to 15 kV.
  • a potential difference of, for example, 10 kV
  • There is no specific limitation also on the type of the applied voltage and any of a pulse voltage, a rectangular voltage and a continuous voltage is available.
  • the jet quantity of the ink composition can be controlled by the applied voltage and the voltage application time.
  • the needle electrode 17 or the linear electrode 18
  • the ink jet electrode as a negative electrode
  • the needle electrode 17 or the linear electrode 18
  • the needle electrode 17 or the linear electrode 18
  • the recording apparatus of the invention is a recording apparatus including an ink jet means having a hole through which an ink-jet recording ink composition comprising an electro-sensitive movable fluid and a colorant dissolved or dispersed in the fluid is jetted correspondingly to the printing signals (i.e., applied voltage); wherein the ink jet means comprises one or plural ink jet electrodes and one or plural source electrodes which are provided in the vicinity of bottom ends of the ink jet electrodes and are electrically insulated from the ink jet electrodes, and a jet flow of the ink composition is produced by applying a voltage between the ink jet electrodes and the source electrodes and thereby the ink composition can be jetted from tips of the ink jet electrodes.
  • the ink jet means comprises one or plural ink jet electrodes and one or plural source electrodes which are provided in the vicinity of bottom ends of the ink jet electrodes and are electrically insulated from the ink jet electrodes, and a jet flow of the ink composition is produced by applying a voltage between the ink jet electrode
  • Fig. 3 schematically shows an embodiment of the recording apparatus of the invention.
  • nozzle-like electrodes are used as the ink jet electrodes.
  • plural nozzle-like electrodes 31 are provided as the ink jet electrodes in an ink jet means 50.
  • plural source electrodes 37 are arranged correspondingly to the plural nozzle-like electrodes 31.
  • the source electrodes 37 are each a needle electrode.
  • the nozzle-like electrode 31 (ink jet electrode) is provided with a through-hole, and this through-hole is generally connected to a tapered through-hole 35 provided in an insulating substrate 30 and in a conductive metallic foil 32 placed on the substrate 30, whereby an ink composition 39 can be jetted out.
  • the jet direction of the ink composition 39 is determined by the nozzle-like electrode 31.
  • a voltage is applied to the ink composition, and the applied voltage can be controlled by, for example, a personal computer 40 or a control means 41.
  • the ink jet electrodes 31 are negative electrodes and the source electrodes 37 (needle electrode) are positive electrodes as shown in Fig. 3, if a voltage is applied to the specific source electrodes 37, the ink composition 39 can be selectively jetted from only the corresponding specific nozzles.
  • the quantity of electricity required for jetting the ink composition is extremely small, and besides heat generation of the ink jet means does not take place even if a voltage is applied.
  • a large number of nozzles ink jet electrodes
  • the quantity of electricity for driving the recording apparatus of the invention is markedly smaller than that of the conventional ink jet printers, and the recording apparatus of the invention is noiseless because of few driving means. Further, high-speed printing is feasible because the nozzles do not need to be moved.
  • a large number of nozzles can be arranged not only in the crosswise direction as described above but also in the lengthwise direction to perform simultaneous multi-color printing.
  • the nozzles may be moved to perform printing.
  • the recording apparatus of the invention has a function of jetting the ink composition from the nozzle upon application of a voltage between the ink jet electrode and the source electrode as described above, and therefore the recording apparatus can be variously modified as far as the apparatus has such a function.
  • the shapes of the nozzle, the ink jet electrode and the source electrode can be variously modified.
  • Fig. 6 schematically shows a multi-step electrode which is another embodiment of the ink jet electrode.
  • the multi-step electrode shown in Fig. 6 consists of a cylinder and plural unit electrodes which are made of a conductive material and disposed in the cylinder.
  • the unit electrode has a hollow cylindrical body made of, for example, a metal, and the hollow portion serves as an ink flow path.
  • a protrusion electrically connected to the cylindrical body is provided at the tip of the cylindrical body.
  • Plural unit electrodes having such structure are disposed in series in the cylinder made of an insulating material in such a manner that each protrusion points to the nozzle opening (i.e., downstream side of the ink flow).
  • the ink composition of the invention moves toward the nozzle opening at the first unit electrode, that is, a jet flow of the ink composition is produced.
  • This jet flow is accelerated at the next unit electrode.
  • the jet flow is successively accelerated and finally comes out from the nozzle.
  • a multi-step electrode having four unit electrodes is arranged at an angle of 30° to the liquid level of the ink composition and if a voltage of 12 kV is applied, the jet distance of the ink composition reaches 200 mm. In case of 15 kV, the jet distance reaches 300 mm.
  • the shape of the unit electrode is not limited to the cylindrical one mentioned above, and the unit electrode may have various shapes such a shape of square flat plate and a shape of circular plate each of which has an ink flow path at the center or thereabout. Also, the protrusion may have various shapes such as a needle shape, a multi-needle shape and a linear shape.
  • plural ink jet electrodes can be so arranged that they together form one ink dot, as shown in Fig. 7.
  • Fig. 7(A) four ink jet electrodes are arranged correspondingly to the needle electrodes.
  • a voltage can be applied to the ink jet electrodes independently, and one ink dot can be printed by these four ink jet electrodes.
  • the ink jet electrode may be in the shape of a flat plate, as shown in Fig. 7(B).
  • the source electrode corresponding to the ink jet electrode may consist of plural needles.
  • the source electrode may be a point electrode or a conical electrode manufactured by utilizing printed wiring technique.
  • the ink jet means comprises the source electrode (needle electrode) and the ink jet electrode, and the ink composition is pushed (jetted) out from the tip of the ink jet electrode by means of the needle electrode and the ink jet electrode.
  • an ink attraction electrode may be further provided to jet the ink composition more efficiently. If the ink attraction electrode is provided to attract the ink composition jetted from the ink jet electrode, the ink composition can be fed to the recording material more finely and more stably.
  • Fig. 8(a) schematically shows a recording system using the ink attraction electrode.
  • numeral 71 designates an ink attraction electrode
  • numeral 73 designates an ink jet electrode
  • numeral 75 designates a needle electrode serving as a source electrode.
  • an ink composition 77 comprising the electro-sensitive movable fluid and the colorant is filled in an ink case 79.
  • the ink composition is fed to the ink case 79 from the outside, and no air is present between the needle electrode 75 and the ink jet electrode 73.
  • the needle electrode 75 is in the shape of a needle, and the tip of the needle points to the hole of the ink jet electrode 73.
  • An ununiform electric field is generated in the ink composition present between the needle electrode 75 and the ink jet electrode 73.
  • the ink attraction electrode 71 has only to be designed so as to attract the ink composition jetted from the ink jet electrode 73, and the shape of the ink attraction electrode 71 is not specifically limited. However, a plane electrode or a linear electrode is preferable. In Fig. 8(a), a plane ink attraction electrode 71 is shown.
  • the ink attraction electrode 71 is generally arranged on the back surface side of a recording material 81 (paper in Fig 8(a)) on which the ink composition jetted from the ink jet electrode 73 impinges.
  • the recording system using the needle electrode 75, the ink jet electrode 73 and the ink attraction electrode 71 includes three types, namely, type A, type B and type C, as shown in Fig. 8(a).
  • Voltages applied to the needle electrode 75, the ink jet electrode 73 and the ink attraction electrode 71 are represented by symbols V S , V D and V P , respectively.
  • V S , V P a relation of V S , V P >> V D is formed among the voltages applied to those electrodes, whereby the ink composition is jetted. That is, the ink jet electrode is grounded to make V D be 0 V, and a direct-current plus voltage (V S ) generating such a potential difference between V S and V D as is incapable of jetting the ink composition is applied to the needle electrode.
  • the ink composition when the plus voltage is in the range of usually +3 kV to +6 kV, preferably +4 kV to +5 kV, the ink composition is not jetted from the ink jet electrode 73.
  • the voltage applied to the ink attraction electrode is changed from 0 V (GND) to +4 kV or +5 kV, the ink composition is jetted from the ink jet electrode 73 toward the ink attraction electrode 71.
  • the voltage V S applied to the needle electrode and the voltage V D applied to the ink jet electrode are kept constant, and only the voltage V P applied to the ink attraction electrode is changed, whereby a relation of V S , V P >> V D is formed among the voltages applied to the three electrodes.
  • the ink composition thus jetted impinges on a recording material (e.g., paper) placed between the ink jet electrode 73 and the ink attraction electrode 71 to perform recording.
  • a recording material e.g., paper
  • V S direct-current minus voltage
  • V S a direct-current minus voltage generating such a potential difference between V S and V D as is incapable of jetting the ink composition
  • the minus voltage is in the range of usually -3 kV to -6 kV, preferably -4 kV to -5 kV, the ink composition is not jetted from the ink jet electrode 73.
  • the ink composition is jetted from the ink jet electrode 73 toward the ink attraction electrode 71.
  • the voltage V S applied to the needle electrode and the voltage V D applied to the ink jet electrode are kept constant, and only the voltage V P applied to the ink attraction electrode is changed, whereby a relation of V S , V P ⁇ V D is formed among the voltages applied to the three electrodes.
  • the ink composition thus jetted is received by the recording material placed between the ink jet electrode 73 and the ink attraction electrode 71 to perform recording.
  • the voltage V S applied to the needle electrode is set to 0 V (GND), and a direct-current plus voltage is applied between the needle electrode and the ink jet electrode.
  • the plus voltage is in the range of usually +3 kV to +6 kV, preferably +4 kV to +5 kV
  • the ink composition is not jetted from the ink jet electrode 73.
  • the voltage applied to the ink attraction electrode is changed from +4 kV or +5 kV to 0 V (GND)
  • the ink composition is jetted from the ink jet electrode 73 toward the ink attraction electrode 71.
  • the voltage V S applied to the needle electrode and the voltage V D applied to the ink jet electrode are kept constant, and only the voltage V P applied to the ink attraction electrode is changed, whereby a relation of V S , V P ⁇ V D is formed among the voltages applied to the three electrodes.
  • the ink composition thus jetted is received by the recording material placed between the ink jet electrode 73 and the ink attraction electrode 71 to preform recording.
  • a flow resistance member 76 may be provided at the hole portion of the ink jet electrode 73.
  • the flow resistance member 76 not only prevents the ink composition, which has been energized by pressure application or the like, from leaking from the tip of the ink jet electrode but also removes dust or the like contained in the ink composition 77 to inhibit clogging of the nozzle. Besides, the flow resistance member 76 prevents drying of the ink composition.
  • the flow resistance member 76 is preferably a filter-like one. Control of the flow rate of the ink composition can be also effected by the flow resistance member 76.
  • the diameter of a pillar of the jetted ink composition becomes small.
  • the feed rate of the ink composition 77 jetted from the ink case 79 is restricted by the resistance, and the pillar of the ink composition is attracted by the external ink attraction electrode 71. Therefore, the pillar of the ink composition naturally becomes fine (slender).
  • the pillar of the ink composition is fine, it can be kept by a balance of the jet action and the attraction action. That is, jetting of a fine pillar of the ink composition can be favorably carried out.
  • the fine pillar of the ink composition a minute ink line can be drawn on the recording material. Therefore, the present invention is suitable for precise recording.
  • Fig. 8(c) shows another embodiment of the on-demand type ink jet head.
  • the voltage V S applied to the needle electrode 75 is changed from a low level to a high level to obtain a relation of V S , V P >> V D for jetting the ink composition.
  • V S is changed from GND to V H , whereby the ink composition is jetted.
  • the voltage Vs is changed from a high level to a low level to obtain a relation of V S , V P ⁇ V D for jetting the ink composition.
  • V S is changed from V H to GND as shown in Fig. 8(c), whereby the ink composition is jetted.
  • the voltage V S is changed from a high level to a low level to obtain a relation of V S , V P ⁇ V D for jetting the ink composition.
  • V S is changed from GND to -V H as shown in Fig. 8(c), whereby the ink composition is jetted.
  • the voltage V D applied to the ink jet electrode 73 is changed from a high level to a low level to obtain a relation of V S , V P >> V D for jetting the ink composition.
  • V D is changed from V H to GND, whereby the ink composition is jetted.
  • the voltage V D is changed from a low level to a high level to obtain a relation of V S , V P ⁇ V D for jetting the ink composition.
  • V D is changed from GND to V H as shown in Fig. 8(d), whereby the ink composition is jetted.
  • the voltage V D is changed from a low level to a high level to obtain a relation of V S , V P ⁇ V D for jetting the ink composition.
  • V D is changed from -V H to GND as shown in Fig. 8(d), whereby the ink composition is jetted.
  • the voltage V p of the ink attraction electrode 71 is changed from a low level to a high level to obtain a relation of V S , V P >> V D for jetting the ink composition.
  • V P is changed from GND to V H , whereby the ink composition is jetted.
  • the voltage V P is changed from a high level to a low level to obtain a relation of V S , V P ⁇ V D for jetting the ink composition.
  • V P is changed from V H to GND as shown in Fig. 8(e), whereby the ink composition is jetted.
  • the voltage V P is changed from a high level to a low level to obtain a relation of V S , V P ⁇ V D for jetting the ink composition.
  • V P is changed from GND to -V H as shown in Fig. 8(e), whereby the ink composition is jetted.
  • the voltage change value to jet the ink composition in the above-mentioned system is an absolute value, and is usually 3 kV to 6 kV, preferably 4 kV to 5 kV.
  • the above-mentioned relations for jetting the ink composition may be formed as shown in Fig. 9.
  • the voltage V P applied to the ink attraction electrode 71 is set lower than the high voltage V H by ⁇ V ( ⁇ V is a value sufficiently smaller than V H ).
  • the voltage V S applied to the needle electrode 75 is set lower than the high voltage V H by ⁇ V. That is, each of V S and V P is decreased by ⁇ V to form a relation of V S , V P > V D .
  • V D is decreased by ⁇ V with maintaining V S and V P as they are, to form a relation of V S , V P >> V D for jetting the ink composition, whereby the ink composition can be jetted.
  • V S , V P > V D among the voltages applied to the electrodes is first formed in the type A.
  • the ink composition is not jetted, but at the ink jet electrode 73, the ink composition comes near being jetted.
  • V D is decreased by ⁇ V.
  • a relation of V S , V P >> V D is formed among the applied voltages, and the ink composition is jetted from the ink jet electrode 73.
  • the ⁇ V value needs only to be considerably smaller than the V H value, and is for example usually about 1/5 to 1/3 of the V H value. Specifically, the ⁇ V value is about 1 kV to 1.2 kV.
  • the applied voltages before and during jetting of the ink composition are as follows.
  • V P GND + ⁇ V (unchanged)
  • V D V H + ⁇ V
  • V S GND + ⁇ V (unchanged)
  • V P and V S are beforehand set higher than GND by ⁇ V, and in order to jet the ink composition, V D is set higher than the prescribed applied voltage V H by ⁇ V, whereby V S , V P and V D satisfy the condition of V S , V P ⁇ V D for jetting the ink composition, and the ink composition can be jetted.
  • V S , V P ⁇ V D among the voltages applied to the electrodes is first formed.
  • the ink composition is not jetted, but at the ink jet electrode 73, the ink composition comes near being jetted.
  • V D is increased by ⁇ V.
  • a relation of V S , V P ⁇ V D is formed among the applied voltages, and the ink composition is jetted from the ink jet electrode 73.
  • the meaning of ⁇ V is the same as described above.
  • the ink composition can be jetted in the same manner as in the type B except that V H in the type B is changed to -V H .
  • the ⁇ V value is an absolute value, and is usually 0.8 kV to 1.5 kV, preferably 1 kV to 1.2 kV.
  • jetting of the ink composition can be controlled by controlling a voltage ⁇ V of low level. Moreover, since the ink composition has come near being jetted, the ink composition can be jetted by a slight change of ⁇ V with a good response. That is, according to this method, the response time can be shortened.
  • the method described above is a method to jet the ink composition correspondingly to the printing signals.
  • printing can be controlled by continuously jetting the ink composition and changing the jet flow (i.e., by allowing a pillar of the ink composition to reach the recording material such as paper), or by blocking the pillar.
  • the pillar of the ink composition is controlled by a gate electrode. As shown in Fig. 10, a voltage is constantly applied to the needle electrode, the ink jet electrode and the ink attraction electrode to continuously form a pillar of the ink composition, while a voltage for printing (printing signal) is applied to the gate electrode 99(a).
  • the ink composition 77 is jetted to form a pillar of the composition in the direction of the ink jet electrode 73 to the ink attraction electrode 71 by means of the needle electrode 75, the ink jet electrode 73 and the ink attration electrode 71.
  • a baffle 83 is arranged between the ink jet electrode 73 and the ink attraction electrode 71.
  • the baffle is provided with an ink-passing hole 98 at such position that the pillar of the ink composition passes through it when a voltage is applied to the gate electrode 99(a) but the pillar of the ink composition impinges on the baffle so as not to reach the recording material 81 when no voltage is applied to the gate electrode 99(a).
  • the ink-passing hole 98 may be a circular hole as shown in the baffle 83a of Fig. 10(a), or may be a slit as shown in the baffle 83b of Fig. 10(a).
  • the ink composition blocked by the baffle is collected and recycled or discarded.
  • the pillar of the ink composition formed by continuous jetting impinges on the baffle 83 as indicated by numeral 1 or 3, followed by collecting the ink composition.
  • the pillar of the ink composition passes through the circular hole or slit 98 as indicated by numeral 2 and reaches the recording material 81.
  • a voltage V G is applied to the gate electrode 99.
  • the pillar of ink composition passes through the ink jet electrode and is jetted from its tip opening. At this time, the pillar of the ink composition is charged with the same polarity as that of the ink jet electrode. If the gate electrode voltage V G is brought close to the ink jet electrode voltage V D , the pillar of the ink composition and the gate electrode repels each other owing to the Coulomb force, and the pillar of the ink composition moves from numeral 1 to numerals 2, 3, as shown in Fig. 10. In this instance, the gate electrode is connected to the ink jet electrode through a switch (SW 1 ), and the gate electrode voltage V G is equal to the ink jet electrode voltage V D .
  • SW 1 switch
  • the pillar stands upright in the SW 1 -off condition as indicated by numeral 1. Then, if a voltage is applied to the gate electrode, the pillar is changed as indicated by numerals 2, 3. Only the pillar indicated by numeral 2 passes through the circular hole or slit 98 of the baffle 83, then is attracted by the ink attraction electrode 71 and arrives at the recording material 81 to form a dot on the recording material 81.
  • the ink composition which has been jetted as indicated by numeral 1 or 3 and has not reached the recording material 81, is collected and recycled or discarded.
  • the pillar (jet line) of the ink composition can be changed as indicated by 1 ⁇ 2 ⁇ 3 or 1 ⁇ 2 shown in Fig. 10.
  • the jet line of the ink composition (sometimes referred to as "ink jet line” hereinafter) is changed as indicated by 1 ⁇ 2 ⁇ 3
  • the ink jet line returns to the initial position as indicated by 3 ⁇ 2 ⁇ 1 when the gate electrode voltage V G is decayed.
  • the ink jet line indicated by numeral 2 is formed twice, and as a result printing is carried out twice.
  • Fig. 11 shows a modification of the recording system shown in Fig. 10.
  • Fig. 11 an embodiment wherein the gate electrode is located near the ink attraction electrode is shown.
  • the gate electrode 99b and the ink attraction electrode 71 may be combined into one body.
  • the gate electrode 99b is connected to the ink attraction electrode 71 through a switch SW 2 .
  • the difference between the voltage V G of the gate electrode 99b and the voltage V D of the ink jet electrode 73 i.e., voltage of the pillar of the ink composition
  • the gate electrode 99b pulls the pillar of the ink composition.
  • the ink jet line is changed as indicated by 1 ⁇ 2 ⁇ 3.
  • the switch SW 2 is turned off to apply no voltage to the gate electrode 99b
  • the ink jet line is changed as indicated by 3 ⁇ 2 ⁇ 1
  • the pillar of the ink composition returns to the initial position.
  • Other operations are the same as those described with respect to Fig. 10.
  • Fig. 12 shows a modification of the recording system shown in Fig. 11.
  • a baffle 83 and a gate electrode 85 are combined into one body.
  • the gate electrode 85 can be connected to an ink jet electrode 73, it is preferable that the gate electrode 85 is connected to an ink attraction electrode 71 through a switch SW 3 as shown in Fig. 12.
  • the ink jet line is changed as indicated by 1 ⁇ 2 ⁇ 3.
  • the ink jet line indicated by numeral 2 passes through a slit 92 and reaches a recording material 81.
  • the switch SW 3 is turned off, the ink jet line is changed as indicated by 3 ⁇ 2 ⁇ 1.
  • Fig. 13 shows an embodiment wherein a baffle 90 and gate electrodes 91a, 91b are combined into one body. As shown in Fig. 13(a), an ink attraction electrode, the baffle and the gate electrode can be combined into one body.
  • the ink attraction electrode is divided into two parts 91a, 91b each of which is allowed to have a function of a gate electrode.
  • the pillar of the ink composition is attracted by the ink attraction electrode 91a and stands upright as indicated by numeral 1. Then, if the switch SW 4 is turned off and if a switch SW 5 is turned on to bring the voltage V P2 close to the voltage V S , the ink jet line is changed as indicated by 1 ⁇ 2 ⁇ 3.
  • the ink jet line indicated by numeral 2 passes through a slit 92 to perform printing (recording) on a recording material 81.
  • the recording material 81 since the recording material 81 is arranged on the back side of the ink attraction electrode, the ink composition having passed through the slit 92 is not jetted up so high. Therefore, the recording material 81 should be arranged at the position not so far from the back surface of the ink attraction electrodes 91a, 91b.
  • Fig. 24 shows another embodiment of the invention.
  • an ink case 79 is provided with a needle electrode 75 and an ink jet electrode 73, and an ununiform electric field is generated in an ink composition 77 filled in the ink case 79.
  • a baffle 83 having an ink-passing hole 92, a recording material 81 and a pair of ink attraction electrodes 191a, 191b electrically insulated from each other are arranged in this order in the ink jet direction of the ink composition from the tip of the ink jet electrode 73.
  • a switch SW 6 is turned on to apply a plus voltage to the ink attraction electrode 191a, and at the same time, a minus voltage is applied to the ink jet electrode 73.
  • the ink composition 77 is jetted from the tip of the ink jet electrode 73 toward the ink attraction electrode 191a, but because of the baffle 83 located between the ink jet electrode 73 and the ink attraction electrode 191a, the pillar of the jetted ink composition impinges on the baffle 83 as indicated by numeral 1 and does not reach the recording material 81.
  • a switch SW 6 is turned off, and at the same time, a switch SW 7 is turned on to apply a plus voltage to the ink attraction electrode 191b, whereby the pillar of the ink composition is attracted by the ink attraction electrode 191b and moves as indicated by numerals 2, 3.
  • the pillar of the ink composition having passed through a slit 92 reaches the recording material 81 to perform printing on the recording material.
  • the needle electrode, the ink jet electrode, the ink attraction electrode, and if desired, the gate electrode and the baffle are provided as described above, and the recording material 81 is moved relatively to the ink jet electrode with applying a voltage to each electrode, whereby the ink composition 77 can be jetted onto the surface the recording material correspondingly to the applied voltage.
  • one or more nozzles (electrode group) having the above structure are arranged to jet the ink composition 77 onto the surface of the recording material 81, and thereby a desired ink pattern is formed.
  • Fig. 14 shows an embodiment wherein two ink jet openings 101 are arranged side by side.
  • the pillars of the ink composition jetted from the ink jet openings 101 repels each other and deviate outward to form ink jet lines a' and b' each of which is positioned on the outer side as compared with the ink jet line a or b formed when only one ink jet opening is arranged.
  • the deviation of the ink jet line is presumably caused by the Coulomb force.
  • the ink composition is not jetted from the adjacent nozzles of the nozzles 101a, 101b, 101c and 101d at the same time but jetted from the nozzles with a time log, namely, at the time t 1 , t 2 , t 3 and t 4 .
  • the deviation of the ink jet line is caused by the Coulomb force generated between the ink jet lines, and therefore, as the distance between the ink jet lines becomes wider, the deviation becomes smaller.
  • the deviation rarely takes place if the ink composition is not jetted from the adjacent nozzles at the same time. Accordingly, if the ink composition is jetted from one nozzle at one time as shown in Fig.
  • the deviation of the ink jet line can be inhibited.
  • the distance between the nozzles used for jetting is sufficiently widened as shown in Fig. 16.
  • the ink composition can be jetted from plural nozzles at the same time.
  • the nozzle distance at which deviation of the ink jet line does not substantially take place is usually 3 to 6 mm, preferably 4 to 5 mm.
  • nozzles 101a to 101d are arranged one-dimensionally.
  • nozzles 101a to 101c, nozzles 102a to 102c and nozzles 103a to 103c are arranged two-dimensionally to widen the distance between the nozzles. That is, the nozzles are arranged in zigzag to form a nozzle line composed of the nozzles 101a to 101c and a nozzle line composed of the nozzles 102a to 102c as shown in the plan view of Fig. 17.
  • the pitch between the nozzles becomes L/ ⁇ 2, and hence printing of higher resolution can be carried out. That is, by the two-dimensional arrangement of nozzles, the nozzle distance can be widened, and therefore deviation of the ink jet line can be reduced even if the recording apparatus has the same resolution.
  • dummy nozzles can be arranged on the periphery of plural nozzles to reduce deviation of the jet lines of the ink composition jetted from the nozzles positioned between the dummy nozzles.
  • deviation of the ink jet lines (a) and (e) from the dummy nozzles arranged on the outermost side becomes largest.
  • the ink jet lines (b), (c) and (d) from the nozzles positioned between the dummy nozzles (a) and (e) as the position of the nozzle comes inner, deviation of the jet line becomes smaller.
  • a recording apparatus substantially free from deviation of ink jet line can be manufactured by effectively arranging dummy electrodes on the periphery of plural nozzles.
  • the dummy nozzles are useful for both of one-dimensional nozzle arrangement and two-dimensional nozzle arrangement.
  • the method of using an ink-jet recording ink composition and the recording apparatus according to the invention can be variously modified.
  • the source electrode is explaind above exemplifying a needle electrode, the source electrode is not limited to the needle electrode, and an electrode of any type is available as far as it can form, together with the ink jet electrode, an ununiform electric field in the ink composition containing the electro-sensitive movable fluid.
  • a conductive material electrically insulated from an ink jet electrode 173 is arranged on the bottom of an ink case 179 provided with the ink jet electrode 173 to form a flat plate source electrode 174.
  • the shape, area, etc. of the flat plate electrode can be varied to form various electrodes such as dot electrode, linear electrode, plane electrode and network electrode.
  • the size of the ink case 179 of the recording apparatus can be made small.
  • a foil, a line and a dot serving as such source electrodes can be formed by utilizing, for example, printed wiring technique.
  • the ink jet electrode can be manufactured by utilizing printed wiring technique. Specifically, a through-hole having a trapezoid section is formed in a printed-wiring board, and a conductive film is deposited on the edge portion of the through-hole by means of plating such as electroless plating.
  • a circularly holed flat plate electrode 180 electrically insulated from the ink jet electrode 173 may be formed to generate an ununiform electric field in an ink composition 177, and thereby the ink composition 177 can be jetted from the tip of the ink jet electrode 173.
  • a network electrode 181 may be arranged in an ink case 179 having an ink jet electrode 173 to generate an ununiform electric field in an ink composition 177, and thereby the ink composition 177 can be jetted from the ink jet electrode 173.
  • the ink composition can be jetted without providing any source electrode, as shown in Fig. 22.
  • an ink composition 177 is energized (for example, continuously pressurized) with controlling jetting of the ink composition 177 from the tip of an ink jet electrode 173 by means of a flow resistance member or the like, whereby such condition that the ink composition comes near being jetted by application of a voltage between the source electrode and the ink jet electrode is formed. Then, the potential of the ink attraction electrode is changed, and as a result, the ink composition can be jetted even if no source electrode is provided. Also in case of providing a source electrode, the ink composition can be jetted similarly to the above by applying a low voltage to the source electrode so as to restrict its function or by allowing the source electrode to have no function as an electrode.
  • a voltage is applied to the ink jet electrode so as to increase a potential difference between the source electrode and the ink jet electrode and between the ink jet electrode and the ink attraction electrode.
  • a voltage corresponding to printing signals may be applied to the ink attraction electrode to jet the ink composition in the direction of the ink attraction electrode.
  • a voltage corresponding to printing signals may be applied to the ink source electrode to jet the ink composition in the direction of the ink attraction electrode.
  • the ratio between the inner diameter of the tip of the ink jet electrode and the outer diameter thereof is in the range of 1:1.00 to 1:3.00.
  • the ratio between the outer diameter of the tip of the ink jet electrode and the length of a flow path in the ink jet electrode is preferably in the range of 1:3 to 1:20. If the ink jet electrode is formed as described above, the ink composition can be more efficiently jetted.
  • the present invention is described hereinbefore with reference to the embodiments wherein the ink composition is jetted upward against the gravity.
  • a recording apparatus wherein the ink composition is jetted in the horizontal direction (i.e., laterally) or the vertical direction (i.e., downward) can be also manufactured.
  • ink jet electrodes are formed in a linear form is only described hereinbefore, the ink jet electrodes may be in the other form, such as a bent-in-right-angle form.
  • the recording apparatus of the invention may contain the following ink jet means.
  • the ink jet means comprises one or plural ink jet electrodes for jetting the ink composition, and at least one pair of ink attraction electrodes which are electrically insulated from the ink jet electrodes and arranged in the jet direction of the ink composition, and at least one through-hole through which the ink composition jetted from the ink jet electrodes toward the ink attraction electrodes passes may be provided to the ink attraction electrodes.
  • the ink composition is allowed to pass through the through-hole of the ink attraction electrodes to reach a recording material, so that printing is performed correspondinly to printing signals.
  • the ink jet electrodes are preferably provided on the side wall or the bottom of ink-keeping unit disposed in the ink jet means.
  • the ink composition is jetted in a horizontal or downward direction from the ink jet electrodes.
  • no source electrode is needed as a liquid pressure is produced.
  • the voltage of -0.5 kV is applied to the ink attraction electrodes, and the voltage at the nozzle electrode turns to 0V.
  • the voltage of +1.4 kV is applied to the nozzle electrodes, so that the ink composition may be jetted.
  • the action occurring between the source electrode and the ink jet electrode can be brought about by utilizing gravity or by externally applying a pressure to the ink composition.
  • a hydraulic pressure of the ink composition depending on the position of the nozzle in the ink tank can be utilized as a part of the jet power.
  • the vertical jet action of the ink composition can be brought about by utilizing a pressure given by pressurizing a closed ink tank.
  • the jet action of the ink composition can be brought about without using application of a voltage between the source electrode and the ink jet electrode, as previously described.
  • the jet power is beforehand controlled so that the ink composition comes near being jetted from the nozzle tip (and that leakage is prevented), and a voltage is applied between the ink jet electrode and the ink attraction electrode to jet the ink composition toward the ink attraction electrode.
  • the source electrode is unnecessary, and hence high effect in the manufacturing cost is obtained.
  • this method is occasionally unsuitable for a system wherein the ink jet properties are precisely controlled based on each nozzle.
  • the source electrode and use of gravity of the ink composition itself or external force given by pressurizing the ink tank may be combined to bring about the ink jet action.
  • the voltage applied to the source electrode can be reduced correspondingly to the external force used, and besides the ink jet properties of each nozzle can be controlled by adjusting the source electrode. As a result, the voltage applied to the source electrode can be lowered, and the switching control can be easily made.
  • the ink-jet recording ink composition employable in the invention comprises an electro-sensitive movable fluid, which is capable of producing a jet flow upon application of a voltage, and a colorant dissolved or dispersed in the fluid.
  • This ink composition can be jetted from a nozzle by applying a voltage to the composition. In the present invention, therefore, heating of the ink composition as in the bubble jet system is unnecessary, and consumption of high electric power as in the ink jet system using piezo element is unnecessary.
  • the ink composition for use in the invention utilizes such properties of the electro-sensitive movable fluid that a jet flow of the fluid is produced upon application of a voltage to the fluid.
  • the ink composition generates no heat even when a voltage is applied, and the electrical energy required for jetting the ink composition is extremely small. Therefore, a printer using the ink composition has the following advantages.
  • a large number of nozzles can be arranged because a pump chamber is unnecessary. Differently from the conventional ink jet printers, the nozzles do not need to be moved, and driving means for moving the nozzles is unnecessary. Therefore, a high-speed and low-noise printer can be provided.
  • the recording apparatus of the invention can be easily miniaturized because nozzles do not need to be moved.
  • the recording apparatus further, application of pressure to the ink composition is not always necessary differently from the bubble jet recording apparatus or the recording apparatus using piezo element. Therefore, no pump chamber needs to be provided, and the structure in the vicinity of the nozzles become extremely simple, so that the recording apparatus of the invention is suitable as a large-sized recording apparatus. Moreover, the ink composition can be stably supplied for a long period of time because it is unnecessary to connect the apparatus to the ink tank by a capillary tube.
  • the ink composition can be continuously jetted by continuously applying a voltage to the electrodes.
  • digital control of the applied voltage is not always necessary. Even when the applied voltage is analogically controlled, the ink composition can be jetted correspondingly to the applied voltage, and fine printing is feasible.
  • an ink attraction electrode may be provided in addition to the ink jet electrode and the source electrode.
  • the ink composition can be jetted toward the ink attraction electrode by beforehand applying a prescribed voltage to the ink jet electrode and to the source electrode and then merely changing the voltage applied to the ink attraction electrode.
  • the voltage applied to the ink attraction electrode serves as a voltage to control jetting of the ink composition.
  • a high voltage is required as a whole to jet the ink composition. For example, it is difficult to perform instantaneous switching at a direct-current-voltage of 5 kV order.
  • the ink composition can be efficiently jetted by beforehand applying a voltage of such a low level that the ink composition is not jetted to the ink attraction electrode and to the source electrode and then applying a relatively low voltage to the ink jet electrode.
  • the voltage required for switching is relatively low, though the applied voltage is high as a whole. Therefore, a recording apparatus having an extremely simple structure and easy controllability can be provided by modifying a commercially available switching element.
  • a copper foil was adhesion bonded to a phenolic plate having a thickness of 1.5 mm, and a conductive metal having a height of 1.7 mm was fusion bonded to the copper foil, as shown in Fig. 1.
  • the phenolic plate had a tapered through-hole (bottom diameter: 3.0 mm, top diameter: 1.5 mm), and each of the copper foil and the conductive metal had a hole (diameter: 1.5 mm) serving as a jet guide and a nozzle-like electrode. In the above bonding, these three holes were connected to each other to form a nozzle.
  • a needle electrode (diameter: 0.9 mm) was arranged near the bottom end of the tapered through-hole of the phenolic plate in such a manner that the tip of the needle electrode entered the tapered through-hole by 0.6 mm and that the needle electrode was not in contact with the phenolic plate.
  • dibutyl decanedioate (DBD) was mixed with 0.03 % by weight of a red dye (Kayaset Red D, available from Nippon Kayaku Co., Ltd.) to dissolve the red dye in dibutyl decanedioate.
  • a red dye Kayaset Red D, available from Nippon Kayaku Co., Ltd.
  • the dibutyl decanedioate had a conductivity of 1.40 ⁇ 10 -9 S/m and a viscosity of 7.0 ⁇ 10 -3 Pa ⁇ s at 25 °C.
  • the above-obtained nozzle equipped with an electrode was arranged on the liquid level of the ink-jet recording red ink composition at an inclination of 20° to the liquid level of the ink composition.
  • the needle electrode and the nozzle-like electrode were set as a positive electrode and a negative electrode, respectively, and a voltage of 6 to 12 kV shown in Table 3 was applied between the needle electrode and the nozzle-like electrode to measure a jet height of the ink composition comprising dibutyl decanedioate and the red dye. The current in the ink composition was also measured.
  • the viscosity and the conductivity (electrical resistance) of the electro-sensitive movable fluid were measured in the following manner by the use of a rheometer (Rheo-Stress RS100, manufactured by HAAKE Co.).
  • the compound (electro-sensitive movable fluid) was interposed between two discs (diameter: 3.5 cm), and a direct-current-voltage of 2 kV was applied to measure a conductivity (S/m at 2 kV/mm) of the compound. Then, one of the discs was rotated to measure a viscosity of the compound.
  • the temperature in the measurements was 25 °C, unless otherwise noted.
  • An ink-jet recording ink composition was prepared in the same manner as in Example 1, except that dibutyl dodecanedioate having a branched chain (Bu-OCO-(CH 2 ) 5 -CH(Bu)-COO-Bu, abbreviated to "DBDD" hereinafter) was used in place of DBD. Then, the jet height and the current were measured in the same manner as in Example 1, except that the above-prepared ink composition was used.
  • the DBDD had a conductivity of 5.2 x 10 -9 S/m and a viscosity of 9.3 ⁇ 10 -3 Pa ⁇ s at 25 °C.
  • Table 4 Voltage (kV) 6.0 7.0 9.0 10.5 12.0 Jet height (mm) 7 17 30 41 53 Current ( ⁇ A) 5.0 8.2 12.0 16.0 19.0
  • An ink-jet recording ink composition was prepared in the same manner as in Example 1, except that linalyl acetate was used in place of DBD. Then, the jet height and the current were measured in the same manner as in Example 1, except that the above-prepared ink composition was used, the diameters of the holes (top diameter of the tapered through-hole of the phenolic plate, diameters of the holes of the copper foil and the conductive metal) were changed to 0.5 mm, and the applied voltage was changed in the range of 4 and 12 kV.
  • the linalyl acetate had a conductivity of 1.82 ⁇ 10 -9 S/m and a viscosity of 1.3 ⁇ 10 -3 Pa ⁇ s at 25 °C. The results are set forth in Table 5. Voltage (kV) 4.0 6.0 7.5 9.0 10.5 12.0 Jet height (mm) 3 5 10 13 15 20 Current ( ⁇ m) 0.7 2.0 2.9 4.5 6.8 7.8
  • An ink-jet recording white ink composition was prepared in the same manner as in Example 1, except that 2.0 % by weight of a titanium oxide powder as a white pigment was homogeneously dispersed in 98 % by weight of DBD. Then, the jet height and the current were measured in the same manner as in Example 1, except that the above-prepared ink composition was used. The results are set forth in Table 6. Voltage (kV) 6.0 7.0 9.0 10.5 12.0 Jet height (mm) 6 12 25 40 49 Current ( ⁇ A) 5.0 8.2 11 16 22
  • An ink-jet recording blue ink composition was prepared in the same manner as in Example 1, except that 1.0 % by weight of phthalocyanine blue as a blue pigment and 0.04 % by weight of 2,2'-dihydroxy-4-methoxybenzophenone were homogeneously dispersed in 98.96 % by weight of DBD. Then, the jet height and the current were measured in the same manner as in Example 1, except that the above-prepared ink composition was used in place of the red ink composition. The results are set forth in Table 7. Voltage (kV) 6.0 7.0 9.0 10.5 12.0 Jet height (mm) 5 10 19 35 42 Current ( ⁇ A) 6.4 8.7 12 15 19
  • An ink-jet recording blue ink composition was prepared in the same manner as in Example 1, except that 1.0 % by weight of phthalocyanine blue as a blue pigment and 0.04 % by weight of 2,2'-dihydroxy-4-methoxybenzophenone were homogeneously dissolved in 98.96 % by weight of linalyl acetate.
  • a copper foil was adhesion bonded to a phenolic plate having a thickness of 1.5 mm, and a conductive metal having a height of 1.7 mm was fusion bonded to the copper foil, as shown in Fig. 3.
  • the phenolic plate had a tapered through-hole (bottom diameter: 3.0 mm, top diameter: 1.5 mm), and each of the copper foil and the conductive metal had a hole (diameter: 1.5 mm) serving as a jet guide and a nozzle-like electrode. In the above bonding, these three holes were connected to each other to form a nozzle.
  • a linear electrode (diameter: 0.2 mm) was placed below the phenolic plate and along the bottom diameter of the tapered through-hole of the phenolic plate. This linear electrode was set as a positive electrode.
  • an ink-jet recording red ink composition was prepared in the same manner as in Example 1.
  • the above-obtained nozzle equipped with an electrode was arranged on the liquid level of the ink-jet recording red ink composition at an inclination of 20° to the liquid level of the ink composition.
  • the linear electrode and the nozzle-like electrode were set as a positive electrode and a negative electrode, respectively, and a voltage of 6 to 12 kV shown in Table 9 was applied between the linear electrode and the nozzle-like electrode to measure a jet height of the ink composition comprising dibutyl decanedioate and the red dye. The current in the ink composition was also measured.
  • the jet height of the ink composition and the current in the ink composition were measured in the same manner as in Example 1, except that the needle electrode and the nozzle-like electrode were set as a negative electrode and a positive electrode, respectively.
  • the jet height of the ink composition and the current in the ink composition were measured in the same manner as in Example 1, except that a multi-step electrode shown in Fig. 6 was used as the electrode.
  • the multi-step electrode had four unit electrodes, and each of the unit electrodes had a cylindrical body (length: 10 mm, inner diameter: 3 mm) and a protrusion (length: 5 mm). The distance between the tip of the protrusion and the lower end of the next unit electrode was 1.5 mm.
  • the black ink composition had a conductivity a of 3.0 ⁇ 10 -9 S/m and a viscosity ⁇ of 8 ⁇ 10 -3 Pa ⁇ s at 2 kV/mm and 25 °C.
  • a needle electrode and an ink jet electrode were immersed in the black ink composition, and an ink attraction electrode was arranged above the ink jet electrode, as shown in Fig. 23.
  • the distance between the ink jet electrode and the ink attraction electrode was 10 mm, and the diameter of the nozzle tip of the ink jet electrode was 0.6 mm.
  • the ink jet electrode was in the form of a cylinder having a diameter of 0.6 mm and a length of 10 mm. The distance between the tip of the needle electrode and the bottom of the ink jet electrode was 2 mm.

Landscapes

  • Inks, Pencil-Leads, Or Crayons (AREA)
  • Ink Jet Recording Methods And Recording Media Thereof (AREA)
  • Ink Jet (AREA)
EP19980308685 1997-10-23 1998-10-23 Aufzeichnungsverfahren unter Benutzung von elektrosensitiven beweglichen Flüssigkeiten und Aufzeichnungsgeräte Withdrawn EP0911164A3 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP290819/97 1997-10-23
JP29081997A JPH11124525A (ja) 1997-10-23 1997-10-23 インクジェット記録方式用インク組成物、該インク組成物の使用方法および該インク組成物を用いた記録装置
JP29081997 1997-10-23

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EP0911164A3 EP0911164A3 (de) 1999-12-15

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Cited By (5)

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EP1439064A1 (de) * 2003-01-15 2004-07-21 Samsung Electronics Co., Ltd. Tintenausstossverfahren und Tintenstrahldruckkopf dafür
EP1645423A3 (de) * 2004-10-07 2007-03-21 FUJIFILM Corporation Tintenstrahlaufzeichnungsgerät und Verfahren
US7559627B2 (en) 2004-03-12 2009-07-14 Infoprint Solutions Company, Llc Apparatus, system, and method for electrorheological printing
US20120251945A1 (en) * 2011-03-28 2012-10-04 Sumitomo Chemical Company, Limited Photoresist composition
WO2021008699A1 (en) * 2019-07-17 2021-01-21 Scrona Ag Electrohydrodynamic print head with structured feed layer

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006001204C5 (de) * 2006-01-10 2015-06-18 Khs Gmbh Verfahren zum Etikettieren von Flaschen oder dergleichen Behältern sowie Etikettiermaschine zum Durchführen des Verfahrens
KR100919411B1 (ko) * 2008-04-25 2009-09-29 연세대학교 산학협력단 전도성 라인형성을 위한 전기수력학 프린팅 장치 및 방법

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JPS55117663A (en) 1979-03-05 1980-09-10 Nec Corp Ink jet recording device
JPH02172746A (ja) 1988-12-27 1990-07-04 Seiko Epson Corp 画像形成方法
JPH03162494A (ja) 1989-11-20 1991-07-12 Ricoh Co Ltd 電場応答性流体
JPH04257485A (ja) 1991-02-12 1992-09-11 Ricoh Co Ltd インク組成物とそれを使用した画像形成方法

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JP2783225B2 (ja) * 1995-12-05 1998-08-06 日本電気株式会社 インクジェット式ヘッド装置
EP0787792B1 (de) * 1996-02-01 2002-11-27 New Technology Management Co., Ltd. Die Verwendung elektrosensitiver beweglicher Flüssigkeiten, Verfahren zur Verwendung und Motoren für diese elektrosensitiven beweglichen Flüssigkeiten
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JPS55117663A (en) 1979-03-05 1980-09-10 Nec Corp Ink jet recording device
JPH02172746A (ja) 1988-12-27 1990-07-04 Seiko Epson Corp 画像形成方法
JPH03162494A (ja) 1989-11-20 1991-07-12 Ricoh Co Ltd 電場応答性流体
JPH04257485A (ja) 1991-02-12 1992-09-11 Ricoh Co Ltd インク組成物とそれを使用した画像形成方法

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1439064A1 (de) * 2003-01-15 2004-07-21 Samsung Electronics Co., Ltd. Tintenausstossverfahren und Tintenstrahldruckkopf dafür
US7264337B2 (en) 2003-01-15 2007-09-04 Samsung Electronics Co., Ltd. Ink ejecting method and ink-jet printhead utilizing the method
US7559627B2 (en) 2004-03-12 2009-07-14 Infoprint Solutions Company, Llc Apparatus, system, and method for electrorheological printing
EP1645423A3 (de) * 2004-10-07 2007-03-21 FUJIFILM Corporation Tintenstrahlaufzeichnungsgerät und Verfahren
US7377622B2 (en) 2004-10-07 2008-05-27 Fujifilm Corporation Ink jet recording apparatus and ink jet recording method
US20120251945A1 (en) * 2011-03-28 2012-10-04 Sumitomo Chemical Company, Limited Photoresist composition
US8753795B2 (en) * 2011-03-28 2014-06-17 Sumitomo Chemical Company, Limited Photoresist composition
WO2021008699A1 (en) * 2019-07-17 2021-01-21 Scrona Ag Electrohydrodynamic print head with structured feed layer

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EP0911164A3 (de) 1999-12-15

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