EP0067687B1 - Encre magnétique ou jet-ink - Google Patents

Encre magnétique ou jet-ink Download PDF

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Publication number
EP0067687B1
EP0067687B1 EP82303043A EP82303043A EP0067687B1 EP 0067687 B1 EP0067687 B1 EP 0067687B1 EP 82303043 A EP82303043 A EP 82303043A EP 82303043 A EP82303043 A EP 82303043A EP 0067687 B1 EP0067687 B1 EP 0067687B1
Authority
EP
European Patent Office
Prior art keywords
magnetic fluid
color
pigment
magnetic
particles
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.)
Expired
Application number
EP82303043A
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German (de)
English (en)
Other versions
EP0067687A3 (en
EP0067687A2 (fr
Inventor
Mamoru Soga
Keiichi Yubakami
Nobuo Sonoda
Wataru Shimotsuma
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Publication of EP0067687A2 publication Critical patent/EP0067687A2/fr
Publication of EP0067687A3 publication Critical patent/EP0067687A3/en
Application granted granted Critical
Publication of EP0067687B1 publication Critical patent/EP0067687B1/fr
Expired legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/44—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of magnetic liquids, e.g. ferrofluids

Definitions

  • This invention relates to an improvement of magnetofluidographic or jet ink (indicated as ink in thefollowing). More specifically, it relates to an improvement of the hue of the magnetic fluid forming the ink.
  • Usual magnetic fluid is a liquid in which magnetic fine particles of magnetite or the like having a particle size of 50-200 A are suspended in a dispersion medium by the aid of surfactant. It has a black-brown color, and it keeps stable for a long period of time so that neither sedimentation nor aggregation readily takes place in it.
  • dispersion medium for such magnetic fluid paraffin oil, ester oil, silicone oil, water and the like are used.
  • the surfactant carboxylic acids such as oleic acid, linoleic acid and the like, as well as cationic surfactants and nonionic surfactants, are used.
  • Such a magnetic fluid is described in EP-A-55065.
  • Magnetic fluid finds use in extensive fields such as sealing agent, lubricant, sink and float separation, oil-water separating agent, recording material and the like.
  • the excellent characteristic properties of the magnetic fluid of this invention can be exhibited particularly in the field of recording material.
  • a magnetic fluid diluted with a dispersion medium to an appropriate viscosity or its mixture with a dye has hitherto been used.
  • the color of this ink is dependent upon the dispersed fine magnetic particles.
  • the fine magnetic particle is y-ferrite, magnetite, Mn ferrite, Ba ferrite, Fe-Zn ferrite or Mn-Zn ferrite, it apparently has a black or black-brown color, but it turns to light brown when it is attached on a support such as paper or the like. This tendency becomes stronger as the magnetic particles become finer.
  • an ink in which a magnetite dispersion type of magnetic fluid is used is a liquid having a black-brown color.
  • the color of the image turns fom black-brown to light brown in several weeks.
  • the color change is due to that the dispersed magnetic fine particles are oxidized by air oxygen to form iron oxide (Fe 2 0 3 ).
  • iron oxide Fe 2 0 3
  • inks using other magnetic fine particles show no great color change, their black-brown color is inclined to light brown from the beginning.
  • the color of magnetic fluid can be converted from brown to black by adding a dye as a colorant to the magnetic fluid.
  • a magnetic fluid containing a dye is formed into an image on white high quality paper, the color of image has a more intense light brown hue than the color of magnetic fluid itself. This is due to the difference in permeability into paper between magnetic fine particles and dye molecule. While the magnetic particle has a size of 50-200 A, the dye molecule has a size of about several ten A or less so that the latter has a greater permeability into high quality paper and the dye molecule h eaches the backside of paper by permeation. Thus, there arises a great difference between the color of magnetic fluid and that of image, which-is an important fault of dye-containing magnetic fluid used as an ink.
  • the object of this invention consists in providing a magnetofluidographic ink or jet ink having various hue. Particularly it consists in providing ink which, when used as a recording material on a high quality paper, is free from color separation between magnetic particle and coloring pigment particle and can give a black-colored image or an arbitrary single color image.
  • the magnetofluidographic or jet ink of this invention can be obtained by stably dispersing coloring pigment particles in a liquid prepared by dispersing ferromagnetic particles by the aid of surfactant, with the proviso that the pigment particles have a particle size of from 50 to 200 A.
  • Figure 1 is an outlined constructional view of magnetofluidographic apparatus
  • Figure 2 is a partial plan view of said apparatus, wherein:
  • the ink of this invention is characterized by being constituted of magnetic particles stably dispersed by the aid of surfactant and colloidal coloring pigment particles having a particle size of 50-200 A.
  • typical colloidal particles have a size of about 10 A to several 100 A.
  • the size of colloidal coloring pigment particle to be dis- . persed in this magnetic fluid is 50-200 A.
  • the colloidal coloring pigment particle has a size comparable to that of the stably dispersed magnetic particle, from the viewpoint of dispersion stability and permeability into paper.
  • a pigment exhibits the maximum hiding power when its size is 0.2-0.3 pm, and pigments usually available commercially have this order of size.
  • the pigment to be dispersed in the magnetic fluid of this invention should most preferably have a size comparable to that of the magnetic particle in the magnetic fluid, it is necessary to make the usually available pigment finely divided.
  • the method for dispersing a pigment into a dispersion medium it is recommendable to pulverize a mixture of pigment, dispersing medium and dispersion stabilizer for a long period of time by means of ball mill, attritor, sand grinder or the like.
  • organic pigments are more preferable than the other in point of coloring power and easiness of pulverization and dispersion. Since inorganic pigments have higher specific gravity and hardness than organic pigments, it takes a longer time to pulverize and disperse inorganic pigments than to do organic pigments. Therefore, in the case of inorganic pigments, it is allowable to add a dispersion stabilizer in synthesizing the pigment by wet process before the pigment particle grows up to form a large particle, by which a pigment having a small particle size can be produced.
  • the inorganic pigments have a structure similar to that of magnetic particle such as ferrite, which can be dispersed into a form of colloid by a process similar to the wet process for the production of magnetic fluid.
  • surfactants exhibit excellent dispersion stability.
  • Surfactants include anionic surfactants, cationic surfactants, nonionic surfactants, etc., any of which exhibit a dispersing action.
  • the action greatly varies with its combination with pigment and dispersion medium. Therefore, surfactants having a functional group readily adsorbable on the pigment are more preferable.
  • the dispersion can be successfully achieved by using a long chain aliphatic carboxylic acid giving a carboxylic acid ion having a strong affinity to metallic oxide, such as oleic acid, or its salt.
  • nonaqueous dispersion media water or nonaqueous dispersion media can be used.
  • the nonaqueous dispersion media include hydrocarbon compounds such as paraffins, aromatic compounds, alicyclic compounds and the like; ethers and esters of aromatic and aliphatic compounds; monohydric and polyhydric alcohol compounds; silicone compounds such as decamethylcyclopentasiloxane, dodecamethyl- cyclohexasiloxane, octadecamethylcyclo- nonasiloxane and the like; and so on.
  • these dispersion media preferably have as low a volatility as possible. Therefore, compounds having a boiling point not lower than 100°C are suitable for use as a solvent for the magnetic fluid.
  • ferromagnetic particles Co, Ni, Fe, their alloys and ferrite compounds can be thought of, among which ferrite compounds are more preferable from the viewpoint of dispersion stability in the presence of surfactant.
  • ferrite compounds y-ferrite, as well as simple divalent ferrites (M"Fe",04; M is metal atom) such as Mn ferrite, magnetite, Co ferrite, Ni ferrite and the like, can be referred to.
  • M simple divalent ferrites
  • Mn ferrite magnetite, Co ferrite, Ni ferrite and the like
  • multi-component ferrites Ni-Zn ferrite, Fe-Zn ferrite, Mn-Zn ferrite, Mn-Fe ferrite, Fe-Ni ferrite and the like can also be referred to.
  • the multi-component ferrites are resistant to oxidation in the air, and the oxidation hardly progresses particularly in case of Mn-Zn and Ni-Zn ferrites. Further, in a recording process in which as high a magnetization as possible in low magnetic field is required (for example, magnetofluidography, Japanese Patent Kokai (Laid-Open) No. 23,534/79), Mn-Zn ferrite is suitable.
  • inorganic pigments a variety of ones can be utilized.
  • blue-colored pigments cobalt blue, ultramarine, Prussian blue, cerulean blue, manganese blue, tungsten blue, molybdenum blue and the like can be referred to.
  • red-colored pigments red oxide, red lead oxide, molybdenum red, cobalt red and the like can be referred to.
  • black-colored pigments carbon black can be referred to as a typical one.
  • pigments of various colors can be used in accordance with the color of magnetic fluid.
  • organic pigment usable in this invention the followings can be referred to.
  • blue-colored pigment there can be referred to phthalocyanine pigments having a high coloring power such as copper phthalocyanine, copper chloride phthalocyanine, metal-free phthalocyanine, 'sulfonated copper phthalocyanine and the like; as well as Erioglaucine (Peacock Blue Lakes), Gracia Peacock Blue (Faste Colors), Rhoduline Peacock Blue, Victoria Blue, Methyl Violet, (tungstic acid), Methyl Violet (molybdic acid), Methyl Violet (tannic acid lakes) and the like.
  • red-colored pigment there can be referred to Para Red, Lithol Rubine, Permanent Red 2B, Pigment Scarlet, Lake Red C, Scarlet Lake 2R, Rose Toner (Fanal Color), Pigment Rubine G (barium, strontium and calcium lakes), Pigment Rubine 3G (barium, strontium and calcium lakes), Alizarine Lake, Lithol Red (sodium salt, barium salt and calcium salt), Toluidine Toner and the like.
  • the pigments of phthalocyanine type particularly have a very high coloring power and are excellent in light resistance, chemical resistance and heat resistance, so that they are most preferable as the coloring pigment used in this invention. It is needless to say that the above-mentioned pigments are nothing other than some examples for the explanation of this invention, and they do not limit the invention.
  • multistylus 1 is set on base pedestal 5, and magnet protrusion 2 is attached by bonding to the multistylus 1 in order to magnetize the latter.
  • the magnet 2 for protrusion is equipped with a feeding magnet 4, by which magnetic fluid is sucked up from the magnetic fluid tank 10 and magnetic fluid 3 is fed to magnet for protrusion 2 and multistylus 1.
  • a protruded port 6 of magnetic fluid 3 having the form shown in Figure 2 is formed on multistylus 1.
  • a mixture consisting of 100 g of copper phthalocyanine, 50 cc of oleic acid and 750 cc of kerosene was pulverized and dispersed by means of sand grinder (1,600 rpm) for a time period of 7 days.
  • the resulting dispersion was mixed with a paraffin base Mn-Zn ferrite dispersion so that the ratio of copper phthalocyanine to ferrite particle came to 1:10 by weight, and viscosity of the dispersion was adjusted to about 6 cp at 20°C with paraffin.
  • recording was carried out by magnetofluidography (construction of the apparatus was as shown in Figure 1).
  • the color of magnetic fluid was blue-black, and the color of the printed image was also blue-black. Neither blurring nor separation of color was observable on the high quality paper. Hue of the printed image hardly changed during a period of several months.
  • viscosity of the magnet fluid was adjusted to 6 cp at 29°C for the reason that, in magnetofluidography, a lower viscosity of magnetic fluid gives a more ready response of magnetic fluid to electric signal and a clearer image. If the viscosity exceeds 20 cp (20°C), the response of magnetic fluid to electric signal becomes difficult to occur and a clear image is unobtainable. Since a paraffin base magnetic fluid having a viscosity of 6 cp at 20°C keeps a viscosity of about 10 cp at 0°C, the present recording experiment was carried out by using a magnetic fluid of which viscosity had been adjusted to 6 cp at 20°C.
  • a mixture consisting of 100 g of cobalt blue (NF-250-P, manufactured by Nippon Ferro K.K.), 50 cc of oleic acid and 750 cc of paraffin was pulverized and dispersed for 7 days by means of sand grinder (1,600 rpm).
  • the resulting dispersion was mixed with a paraffin base Mn-Zn ferrite dispersion so that the ratio of cobalt to ferrite particles came to 1:4 by weight.
  • the color of the magnetic fluid was slightly bluish black, and the color of printed image was also nearly the same as it. Neither blurring nor separation of color was observable on high quality paper.
  • a mixture consisting of 100 g of Prussian Blue, 50 cc of oleic acid and 700 cc of paraffin was pulverized and dispersed for 10 days by means of sand grinder (1,600 rpm).
  • the resulting dispersion was mixed with a paraffin base Mn-Zn ferrite dispersion so that the ratio of Prussian blue to ferrite particles came to 1:5 by weight.
  • a recording experiment was carried out by magnetofluidography.
  • the color of the magnetic fluid was blue-black, and the printed image also had the same blue-black color. Neither blurring nor separation of color was observable on high quality paper. This sample of printed image scarcely showed a change of hue during several months.
  • Example 3 The experiment of Example 3 was repeated, except that the Prussian blue was replaced with ultramarine.
  • the printed image had the same blue-black color as that of magnetic fluid. Neither blurring nor separation of color was observable on high quality paper. No change was observable in hue during several months.
  • a mixture consisting of 100 g of carbon black (M5 manufactured by Mitsubishi Kasei K.K.) and 800 cc paraffin was pulverized and dispersed by means of sand grinder (1,600 rpm) for days.
  • the resulting dispersion was mixed with the copper phthalocyanine dispersion obtained in Example 1 and a paraffin base Mn-Zn ferrite dispersion so that the ratio of copper phthalocyanine, carbon black and ferrite particles came to 1:1:10 by weight.
  • the magnetic fluid was recorded on a high quality paper by magnetofluidography.
  • the color of the printed image was black, and the color of the magnetic fluid was also black. Neither blurring nor separation of color was observable on high quality paper.
  • the hue of the printed image scarcely changed during several months.
  • a magnetic fluid which, when used as a recording material, enables a high speed recording, shows no separation of color on high quality paper and gives a high quality record having a stable hue.
  • the ink of this invention has been developed as a recording ink utilizing the phenomenon of protrusion of magnetic fluid under magnetic force, it is also usable as a recording ink for ink jet, ball point pen and the like.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inks, Pencil-Leads, Or Crayons (AREA)
  • Soft Magnetic Materials (AREA)

Claims (4)

1. Encre magnétofluidographique ou de jet, préparée à partir d'un fluide magnétique composé de particules ferromagnétiques dispersées dans un milieu de dispersion sous l'action d'un surfactif et de particules colloïdales de pigment colorant, également dispersées dans le milieu de dispersion, les particules de pigment ayant une grosseur de particules de 50 à 200 À.
2. Encre selon la revendication 1, dans laquelle les particules ferromagnétiques sont des particules d'un ferrite composite de Mn-Zn ou sont des particules de Fe, Co, Ni ou de leurs alliages.
3. Encre selon la revendication 1 ou 2, dans laquelle le milieu de dispersion est l'eau ou un solvant organique qui est un ou plusieurs est hydrocarbures, un ou plusieurs esters, une ou plusieurs cétones, un ou plusieurs éthers, un ou plusieurs alcools et/ou un ou plusieurs silicones.
4. Encre selon l'une quelconque des revendications 1 à 3, dans laquelle le pigment colorant est un pigment de phtalocyanine.
EP82303043A 1981-06-12 1982-06-11 Encre magnétique ou jet-ink Expired EP0067687B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP9117781A JPS57205466A (en) 1981-06-12 1981-06-12 Magnetic ink for recording
JP91177/81 1981-06-12

Publications (3)

Publication Number Publication Date
EP0067687A2 EP0067687A2 (fr) 1982-12-22
EP0067687A3 EP0067687A3 (en) 1983-12-07
EP0067687B1 true EP0067687B1 (fr) 1987-04-01

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP82303043A Expired EP0067687B1 (fr) 1981-06-12 1982-06-11 Encre magnétique ou jet-ink

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EP (1) EP0067687B1 (fr)
JP (1) JPS57205466A (fr)
DE (1) DE3275962D1 (fr)

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59179569A (ja) * 1983-03-29 1984-10-12 Canon Inc 記録液
GB8423691D0 (en) * 1984-09-19 1984-10-24 Er Fluid Dev Servo-operated torque controlling devices
US4604229A (en) * 1985-03-20 1986-08-05 Ferrofluidics Corporation Electrically conductive ferrofluid compositions and method of preparing and using same
EP0206516A3 (fr) * 1985-05-21 1988-08-10 Ferrofluidics Corporation Composition liquide magnétique, méthode de fabrication et dispositif et méthode pour son application
FR2634775B1 (fr) * 1988-07-29 1990-09-14 Bull Sa Procede d'obtention d'un materiau magnetique transparent a la lumiere et de forte resistivite
DE4115608A1 (de) * 1991-05-14 1992-11-19 Basf Ag Magnetisches tintenkonzentrat
GB2313608B (en) * 1993-04-21 1998-01-21 Dotspec Ltd Improvements in or relating to deinking of paper
US5685952A (en) * 1993-04-21 1997-11-11 Owen; David Malcolm Deinking of paper using magnetic forces
GB9308250D0 (en) * 1993-04-21 1993-06-02 Dotspec Ltd Improvements in or relating to deinking of paper
RU2193251C2 (ru) * 2001-01-09 2002-11-20 Ярославский государственный технический университет Способ получения магнитной жидкости
JP4996984B2 (ja) * 2007-06-01 2012-08-08 トッパン・フォームズ株式会社 磁気インクとその製造方法ならびに磁気パターンとそれを有するシート

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4101646A (en) * 1970-05-13 1978-07-18 Rikagaku Kenkyusho Ferrite vascular contrast media
US3928220A (en) * 1973-08-27 1975-12-23 Gen Electric Preparation of hydrocarbon-dispersible magnetic microspheroids in powdered form
US4094804A (en) * 1974-08-19 1978-06-13 Junzo Shimoiizaka Method for preparing a water base magnetic fluid and product
US4280918A (en) * 1980-03-10 1981-07-28 International Business Machines Corporation Magnetic particle dispersions
JPS57105469A (en) * 1980-12-19 1982-06-30 Matsushita Electric Ind Co Ltd Magnetic ink for recording

Also Published As

Publication number Publication date
EP0067687A3 (en) 1983-12-07
EP0067687A2 (fr) 1982-12-22
JPS57205466A (en) 1982-12-16
DE3275962D1 (en) 1987-05-07

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