EP0656129B1 - Poudre toner attirable de maniere electrostatique et/ou magnetique - Google Patents

Poudre toner attirable de maniere electrostatique et/ou magnetique Download PDF

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Publication number
EP0656129B1
EP0656129B1 EP94918827A EP94918827A EP0656129B1 EP 0656129 B1 EP0656129 B1 EP 0656129B1 EP 94918827 A EP94918827 A EP 94918827A EP 94918827 A EP94918827 A EP 94918827A EP 0656129 B1 EP0656129 B1 EP 0656129B1
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EP
European Patent Office
Prior art keywords
resin
toner
compound
toner powder
dry toner
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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.)
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EP94918827A
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German (de)
English (en)
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EP0656129A1 (fr
Inventor
Serge Martin Tavernier
Werner Jozef Op De Beeck
Jean-Pierre Albert Ghekiere
Michel Remi Vervoort
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Agfa Gevaert NV
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Agfa Gevaert NV
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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/09—Colouring agents for toner particles
    • G03G9/0926—Colouring agents for toner particles characterised by physical or chemical properties
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G13/00—Electrographic processes using a charge pattern
    • G03G13/20—Fixing, e.g. by using heat
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08702—Binders for toner particles comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • G03G9/08706—Polymers of alkenyl-aromatic compounds
    • G03G9/08708—Copolymers of styrene
    • G03G9/08711—Copolymers of styrene with esters of acrylic or methacrylic acid
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08742—Binders for toner particles comprising macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • G03G9/08755—Polyesters
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08784—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775
    • G03G9/08797—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775 characterised by their physical properties, e.g. viscosity, solubility, melting temperature, softening temperature, glass transition temperature
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/09—Colouring agents for toner particles
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/097—Plasticisers; Charge controlling agents
    • G03G9/09733—Organic compounds
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/097—Plasticisers; Charge controlling agents
    • G03G9/09733—Organic compounds
    • G03G9/09775—Organic compounds containing atoms other than carbon, hydrogen or oxygen

Definitions

  • the present invention relates to a toner composition suited for development of electrostatic charge images or magnetic patterns.
  • an electrostatic latent image is formed by the steps of uniformly charging a photoconductive member and imagewise discharging it by an imagewise modulated photo-exposure.
  • an electrostatic latent image is formed by imagewise depositing electrically charged particles, e.g. from electron beam or ionized gas (plasma) onto a dielectric substrate.
  • electrically charged particles e.g. from electron beam or ionized gas (plasma) onto a dielectric substrate.
  • the obtained latent images are developed, i.e. converted into visible images by selectively depositing thereon light absorbing particles, called toner particles, which usually are triboelectrically charged.
  • a latent magnetic image is formed in a magnetizable substrate by a patternwise modulated magnetic field.
  • the magnetizable substrate must accept and hold the magnetic field pattern required for toner development which proceeds with magnetically attractable toner particles.
  • dry development the application of dry toner powder to the substrate carrying the latent electrostatic image may be carried out by different methods known as, “cascade”, “magnetic brush”, “powder cloud”, “impression” or “transfer” development also known as “touchdown” development described e.g. by Thomas L. Thourson in IEEE Transactions on Electronic Devices, Vol. ED-19, No. 4, April 1972, pp.495-511.
  • the visible image of electrostatically or magnetically attracted toner particles is not permanent and has to be fixed by causing the toner particles to adhere to the final substrate by softening or fusing them followed by cooling. Normally fixing proceeds on more or less porous paper by causing or forcing the softened or fused toner mass to penetrate into the surface irregularities of the paper.
  • Dry-development toners essentially comprise a thermoplastic binder consisting of a thermoplastic resin or mixture of resins (ref. e.g. US-P 4,271,249) including colouring matter, e.g. carbon black or finely dispersed dye pigments.
  • the triboelectrically chargeability is defined by said substances and may be modified with a charge controlling agent.
  • the toner particles are deposited at low coverage and do not form a closed or solid deposit of black or coloured material.
  • toner particles are piled on each other and co-fused to form a closed toner-crust which optically has a quite different look as the separately fixed toner particles in the low density portions.
  • Separately deposited and fixed toner particles or small clusters thereof give rise to a light-straying effect. In particular by inspecting the copy with light directed thereto at small grazing angle the small density parts show a mat (dull) appearance.
  • Such process includes : (1) an oven heating process in which heat is applied to the toner image by hot air over a wide portion of the support sheet, (2) a radiant heating process in which heat is supplied by infrared and/or visible light absorbed in the toner, the light source being e.g. an infrared lamp or flash lamp.
  • radiation such as infrared radiation may be at least partly absorbed in the final support and therefrom by conduction transferred to the thereon deposited toner image(s).
  • non-contact fusing the heat reaches the non-fixed toner image through its substrate by contacting the support at its side remote from the toner image with a hot body, e.g. hot metallic roller.
  • a hot body e.g. hot metallic roller.
  • Non-contact fusing has the advantage that the non-fixed toner image does not undergo any mechanical distortion and fine image details will not suffer from transfer to a contacting fixing member, by so-called "offset" phenomena typical for hot pressure roller fusing.
  • a heating roller also called fuser roller and another roller backing the support and functioning as pressure exerting roller, called pressure roller.
  • This roller may be heated to some extent so as to avoid strong loss of heat within the copying cycle.
  • toner-contacting pressure fuser rollers can distort the dot structure of the screened images. Such will be particularly the case when the pressure-fuser roller has no perfect smooth structure and texturizes the obtained image.
  • a dry powder toner the particles of which are electrostatically or magnetically attractable and suitable for use in the development of electrostatic charge images or magnetic patterns and wherein the composition of said powder particles includes at least one transparent thermoplastic resin P and at lest one compound Q, said compound Q having a more polar character than said resin P, characterized in that said at least one resin P and said at least one compound Q when after been mixed in molten state followed by solidification form a light-scattering composition that under the measurement conditions of the following test R has a corrected optical absorption value (A cor ) as described in said test R of more than 0.10 but not more than 1.0, said resin(s) P and compound(s) Q being present in said toner in a weight ratio range P/Q from 5:1 to 1:5, and the weight ratio of P + Q with respect to the total weight of the toner is equal to or larger than 25:100.
  • a cor corrected optical absorption value
  • the toner particles according to the present invention normally contain a colorant but may be colourless for obtaining a desired surface aspect.
  • Resin material P and compound Q are pulverized to a particle size smaller than 1 mm.
  • a powder mixture of P and Q is made taken equal weight amounts of said both ingredients.
  • the powder mixture is fed to a single shaft screw-extruder of bore diameter 19 mm and length 25 times said diameter.
  • the extruder is heated in such a way that the temperture of the extruded product is between 100 and 120 °C at 50 screw revolutions per minute and the molten product is extruded through a slit to form a ribbon having a thickness of about 500 ⁇ m.
  • a part of that ribbon is put on a microscope glass carrier plate and conditioned thereon for 10 minutes at 145 °C.
  • the resultant thickness of the film (about 250 ⁇ m) is measured and the optical absorption of the film determined by means of a double beam spectrophotometer type ACTA CIII (tradename of BECKMAN Instruments, Inc., Fullerton, CA 92634 U.S.A.) operating with light of 540 nm.
  • the weight ratio of P + Q with respect to the total weight of the toner is prefereably equal to or larger than 75:100.
  • a heat-fixed toner image showing satin-look can be obtained already when said "corrected" optical absorption density value (A cor ) for the test mixture of resin(s) P and compound(s) Q is at least 0.1, but preferably said optical density is in the range of 0.3 to 0.7.
  • said absorption density value exceeds 1.0 the incompatibility of P and Q begins to pose serious problems in that the toner composition becomes too strongly inhomogeneous.
  • said weight ratio range P/Q is 3:1 to 1:3.
  • the resin(s) P and compound(s) Q do not disturb an even distribution of the other toner ingredients such as colouring matter, charge controlling agents, flowing agents, etc.
  • said resin(s) P acting as binder in the toner have preferably a glass transition temperature (Tg) larger than 45 °C, and preferably a melt viscosity smaller than 10,000 poise at 120 °C as determined by Test V described furtheron.
  • Tg glass transition temperature
  • a first rough criterion to select a compound Q in combination with a chosen toner resin P is based on the use of the HILDEBRAND solubility parameter for said compound Q with respect to said resin P, that may be a mixture of resins A and B.
  • HILDEBRAND solubility parameter is described in the book "The Solubility of Non-electrolytes" by J.H. Hildebrand and R.L. Scott, Dover Publications, Inc., New York, 3th. ed. (1964).
  • the desired effect of satin-look of fused and solidified toner may be obtained by mixing polymers being selected in such a way that they have slight incompatibility with respect to each other.
  • the HILDEBRAND parameter solubility for polymers is described in the book “Properties of Polymers” by D.W. Van Krevelen, 2nd. ed., Elseviers Scientific Publishing Company, New York, 1976, Chapter 7.
  • thermoplastic resin P e.g. a polyester
  • compound Q having a more polar character than said resin.
  • more polar character is meant possesing a higher dielectric constant and/or better wettability by water.
  • a water-insoluble polyester is used as resin P in combination with a compound Q including ether units such as ethylene oxide units or amino units such as dialkyl-amino units.
  • said resin P is a polyester derived from an aliphatic dicarboxylic acid and a diol being a propoxylated Bisphenol A.
  • first resin A being a polyester resin with low (less than 5.5 mol/kg) carbonyloxy group (-CO.O-) content (the carbonyloxy groups are part of the ester groups), which resin A is preferably derived from a non-aromatic dicarboxylic acid, e.g.
  • resin B being a polyester with high (at least 7.5 mol/kg) carbonyloxy group content
  • resin B is preferably a polyester derived from an aromatic dicarboxylic acid and a diol.
  • the latter polyester is preferably derived from terephthalic acid and isophthalic acid, or mixtures thereof.
  • the diol is preferably ethylene glycol optionally mixed with DIANOL 22 and DIANOL 33 as long as the ethylene glycol content of the totality of diols is more than 50 mol %, preferably at least 60 mol %.
  • Good satin-look results are obtained likewise by using as polymeric compound P a polyester in combination with a compound Q being a styrene-acrylic resin having a relatively high (more than 70 mol %) styrene content, more particularly copolymers of styrene-acrylic resins or styrene-methacrylic resins, e.g. copoly(styrene/n-butylmethacrylate) or copoly(styrene/2-ethyl-hexylacrylate).
  • polymeric compound P a polyester in combination with a compound Q being a polyether compound, known as CARBOWAX (registered tradename).
  • Polyester resins suitable for use according to the present invention are selected e.g. from the group of linear polycondensation products of (i) difunctional organic acids, e.g. maleic acid, fumaric acid, terephthalic acid and isophthalic acid and (ii) difunctional alcohols (diol) such as ethylene glycol, triethylene glycol, an aromatic dihydroxy compound, preferably a bisphenol such as 2,2-bis(4-hydroxyphenyl)-propane called "Bisphenol A" or an alkoxylated bisphenol, e.g. propoxylated bisphenol examples of which are given in US-P 4,331,755.
  • difunctional organic acids e.g. maleic acid, fumaric acid, terephthalic acid and isophthalic acid
  • difunctional alcohols diol
  • diol such as ethylene glycol, triethylene glycol, an aromatic dihydroxy compound, preferably a bisphenol such as 2,2-bis(4-hydroxyphenyl)-propane called "Bisphenol
  • a particularly suitable resin P is a linear polyester of fumaric acid and di-propoxylated bisphenol A, having a melt viscosity of 1800 poise and a Tg of about 50 °C.
  • the glass transition temperature (Tg) mentioned herein is determined according to ASTM Designation : D 3418-82.
  • melt viscosity mentioned herein is determined by the following test V.
  • a RHEOMETRICS dynamic rheometer RVEM-200 (One Possumtown Road, Piscataway, NJ 08854 USA) is used.
  • the viscosity measurement is carried out at a sample temperature of 120 °C.
  • the sample having a weight of 0.75 g is applied in the measuring gap (about 1.5 mm) between two parallel plates of 20 mm diameter one of which is oscillating about its vertical axis at 100 rad/sec and amplitude of 10 ⁇ 3 radians.
  • the measurement signals which are expressed in poise (P) the sample is allowed to attain thermal equilibrium for 10 minutes.
  • polyester resins examples include glass transition temperature (Tg), melt viscosity, weight-average molecular weight(Mw), number-average molecular weight (Mn), and carbonyloxy content (CC) expressed in (mol/kg).
  • Tg glass transition temperature
  • Mw weight-average molecular weight
  • Mn number-average molecular weight
  • CC carbonyloxy content
  • TABLE 1 Resin No. Tg °C Melt visc. poise M w M n CC mol/kg Polyester A1 1 50.5 1800 14,000 4,500 4.88 Polyester B1 2 65 5500 11,500 3,700 7.19 Polyester C1 3 63 7000 16,000 3,500 8.33 Polyester D1 4 69 16000 25,500 7,100 13.89 Polyester A1 is ATLAC T500 (tradename).
  • Polyester B1 is an aromatic polyester resin derived from terephthalic acid (100 mol %) as aromatic diacid and a mixture of DIANOL 33 (50 mol %) and ethylene glycol (50 mol %) as diols
  • Polyester C1 is an aromatic polyester resin derived from terephthalic acid (40 mol %), isophthalic acid (60 mol %) as aromatic di-acids and a mixture of DIANOL 22 (40 mol %) and ethylene glycol (60 mol %).
  • Polyester D1 is an aromatic polyester resin derived from terephthalic acid (64 mol %), isophthalic acid (36 mol %) as aromatic di-acids and ethylene glycol (100 mol %).
  • a cor values were determined for pairs of resins of the above Table 1. Mixtures of resins 1 and 3 yield an A cor value of 0.50, mixtures of resins 1 and 4 yield an A cor value of 0.53, whereas mixtures of resins 1 and 2 yield an A cor value of 0.017, being not within the claim of the present invention.
  • styrene copolymers examples include glass transition temperature (Tg), melt viscosity, weight-average molecular weight (Mw) and number-average molecular weight (Mn). TABLE 2 Resin No. Tg °C Melt visc. poise M w M n S1 1 67 17,000 33,000 13,000 S2 2 68 2,850 6,500 2,000 Resin S1 is a copolymer of styrene and methyl acrylate in a 65/35 molar ratio. Resin S2 is a terpolymer of styrene, methyl acrylate and dimethylaminoethyl methacrylate in a 87/3/10 molar ratio.
  • Tg glass transition temperature
  • Mw weight-average molecular weight
  • Mn number-average molecular weight
  • These compounds Q are applied preferably in combination with a polyester resin as binder.
  • Compound Q has not to be an organic compound, inorganic compounds that fulfil the requirements of the above described test R may be used as well.
  • inorganic compounds that fulfil the requirements of the above described test R may be used as well.
  • colloidal inorganic fillers in such as colloidal silica, alumina and/or titanium dioxide in minor amounts.
  • inorganic fillers may give rise to an undesired high melt viscosity, the need for higher fusing energies and may inhibit a bright color rendition.
  • the toner powder contains in the resinous binder a colorant which may be black or having a colour of the visible spectrum, not excluding however the presence of mixtures of colorants to produce black or a particular colour.
  • a resin blend as defined herein is mixed with said colouring matter which may be dispersed in said blend or dissolved therein forming a solid solution.
  • the colorant is usually an inorganic pigment which is preferably carbon black, but is likewise e.g. black iron (III) oxide.
  • Inorganic coloured pigments are e.g. copper (II) oxide and chromium (III) oxide powder, milori blue, ultramarine cobaltblue and barium permanganate.
  • carbon black examples include lamp black, channel black and furnace black e.g. SPEZIALSCHWARZ IV (trade name of Degussa Frankfurt/M - Germany) and VULCAN XC 72 and CABOT REGAL 400 (trade names of Cabot Corp. High Street 125, Boston, U.S.A.).
  • magnetizable metals including iron, cobalt, nickel and various magnetizable oxides, e.g. heamatite (Fe2O3), magnetite (Fe3O4), CrO2 and magnetic ferrites, e.g. these derived from zinc, cadmium, barium and manganese.
  • various magnetic alloys e.g. permalloys and alloys of cobalt-phosphors, cobalt-nickel and the like or mixtures of these.
  • Toners for the production of colour images may contain organic colorants that may be dyes soluble in the binder resin or pigments including mixtures thereof. Particularly useful organic colorants are selected from the group consisting of phthalocyanine dyes, quinacridone dyes, triaryl methane dyes, sulphur dyes, acridine dyes, azo dyes and fluoresceine dyes. A review of these dyes can be found in "Organic Chemistry” by Paul Karrer, Elsevier Publishing Company, Inc. New York, U.S.A (1950).
  • the colorant is preferably present therein in an amount of at least 1 % by weight with respect to the total toner composition, more preferably in an amount of 1 to 10 % by weight.
  • Black toner particles according to the present invention for use in fixing by infrared radiant units have preferably a melt viscosity of the powder mass (as defined by test V herein) lower than 7000 P.
  • Colourless toners for use in said fixing unit have preferably a melt viscosity not exceeding 2500 P, and colour toners depending on their radiation absorption have preferably a melt viscosity between 7000 and 3000 P.
  • the toner particles may contain (a) charge control agent(s).
  • charge control agent(s) for example, in published German patent application (DE-OS) 3,022,333 charge control agents for yielding negatively chargeable toners are described.
  • Very useful charge controlling agents for providing a net positive charge to the toner particles are described in US-P 4,525,445, more particularly BONTRON NO4 (trade name of Oriental Chemical Industries - Japan) being a nigrosine dye base neutralized with acid to form a nigrosine salt, which is used e.g.
  • a charge control agent suitable for use in colourless or coloured toner particles is zinc benzoate and reference therefor is made to published European patent Application 0 463 876 decribing zinc benzoate compounds as charge controlling agents. Such charge controlling agent may be present in an amount up to 5 % by weight with respect to the toner particle composition.
  • spacing particles may be incorporated therein. Said spacing particles are embedded in the surface of the toner particles or protruding therefrom.
  • These flow improving additives are preferably extremely finely divided inorganic or organic materials the primary (i.e. non-clustered) particle size of which is less than 50 nm.
  • fumed inorganics of the metal oxide class e.g. selected from the group consisting of silica (SiO2), alumina (Al2O3), zirconium oxide and titanium dioxide or mixed oxides thereof which have a hydrophilic or hydrophobized surface.
  • Fumed metal oxides are prepared by high-temperature hydrolysis of the corresponding vaporizable chlorides according to the following reaction scheme illustrative for the preparation of fumed Al2O3 : 4 AlCl3 + 6 H2 + 3 O2 ---- 2 Al2O3 + 12 HCl
  • the fumed metal oxide particles have a smooth, substantially spherical surface and before being incorporated in the toner mass are preferably coated with a hydrophobic layer, e.g. formed by alkylation or by treatment with organic fluorine compounds. Their specific surface area is preferably in the range of 40 to 400 m/g.
  • the proportions for fumed metal oxides such as silica (SiO2) and alumina (Al2O3) incorporated in the particle composition of the toner particles are in the range of 0.1 to 10 % by weight.
  • Fumed silica particles are commercially available under the tradenames AEROSIL and CAB-O-Sil being trade names of Degussa, Franfurt/M Germany and Cabot Corp. Oxides Division, Boston, Mass., U.S.A. respectively.
  • AEROSIL R972 (tradename) is used which is a fumed hydrophobic silica having a specific surface area of 110 m/g. The specific surface area can be measured by a method described by Nelsen and Eggertsen in "Determination of Surface Area Adsorption measurements by continuous Flow Method", Analytical Chemistry, Vol. 30, No. 9 (1958) p. 1387-1390.
  • a metal soap e.g. zinc stearate may be present in the toner particle composition.
  • dispersing or dissolving (a) flow-improving additive(s) in the resin mass of the toner particle composition they may be mixed with the toner particles, i.e. are used in admixture with the bulk of toner particles.
  • zinc stearate has been described in the United Kingdom Patent Specification No. 1,379,252, wherein also reference is made to the use of fluor-containing polymer particles of sub-micron size as flow improving agents.
  • Silica particles that have been made hydrophobic by treatment with organic fluorine compounds for use in combination with toner particles are described in published EP-A 467439.
  • the toner powder particles according to the present invention are prepared by mixing the above defined binder and ingredients in the melt phase, e.g. using a kneader.
  • the kneaded mass has preferably a temperature in the range of 90 to 140 °C, and more preferably in the range of 105 to 120 °C.
  • After cooling the solidified mass is crushed, e.g. in a hammer mill and the obtained coarse particles further broken e.g. by a jet mill to obtain sufficiently small particles from which a desired fraction can be separated by sieving, wind sifting, cyclone separation or other classifying technique.
  • the actually used toner particles have preferably an average diameter between 3 and 20 ⁇ m determined versus their average volume, more preferably between 5 and 10 ⁇ m when measured with a COULTER COUNTER (registered trade mark) Model TA II particle size analyzer operating according to the principles of electrolyt displacement in narrow aperture and marketed by COULTER ELECTRONICS Corp. Northwell Drive, Luton, Bedfordshire, LC 33, UK.
  • COULTER COUNTER registered trade mark
  • Model TA II particle size analyzer operating according to the principles of electrolyt displacement in narrow aperture and marketed by COULTER ELECTRONICS Corp. Northwell Drive, Luton, Bedfordshire, LC 33, UK.
  • an electrolyte e.g. aqueous sodium chloride
  • the particles passing one-by-one each displace electrolyte in the aperture producing a pulse equal the displaced volume of electrolyte.
  • particle volume response is the basis for said measurement.
  • Suitable milling and air classification may be obtained when employing a combination apparatus such as the Alpine Fliessbeth-Gegenstrahlmühle (A.G.F.) type 100 as milling means and the Alpine Turboplex Windsichter (A.T.P.) type 50 G.C as air classification means, available from Alpine Process Technology, Ltd., Rivington Road, Whitehouse, Industrial Estate, Runcorn, Cheshire, UK.
  • A.G.F. Alpine Fliessbeth-Gegenstrahlmühle
  • A.T.P. Alpine Turboplex Windsichter
  • Another useful apparatus for said purpose is the Alpine Multiplex Zick-Zack reformer also available from the last mentioned company.
  • a flow improving agent is added in high speed stirrer, e.g. HENSCHEL FM4 of Thyssen Henschel, 3500 Kassel Germany.
  • the powder toner particles according to the present invention may be used as mono-component developer, i.e. in the absense of carrier particles but are preferably used in a two-component system comprising carrier particles.
  • toner particles When used in admixture with carrier particles, 2 to 10 % by weight of toner particles is present in the whole developer composition. Proper mixing with the carrier particles may be obtained in a tumble mixer.
  • Suitable carrier particles for use in cascade or magnetic brush development are described e.g. in United Kingdom Patent Specification 1,438,110.
  • the carrier particles may be on the basis of ferromagnetic material e.g. steel, nickel, iron beads, ferrites and the like or mixtures thereof.
  • the ferromagnetic particles may be coated with a resinous envelope or are present in a resin binder mass as described e.g. in US-P 4,600,675.
  • the average particle size of the carrier particles is preferably in the range of 20 to 300 ⁇ m and more preferably in the range of 30 to 100 ⁇ m.
  • iron carrier beads of a diameter in the range of 50 to 200 ⁇ m coated with a thin skin of iron oxide are used.
  • Carrier particles with spherical shape can be prepared according to a process described in United Kingdom Patent Specification 1,174,571.
  • the solidified mass was pulverized and milled using an ALPINE Fliessbettarnastrahlmühle type 100AFG (tradename) and further classified using an ALPINE multiplex zig-zag classifier type 100MZR (tradename).
  • the average particle diameter of the separated toner was measured by Coulter Counter model Multisizer (tradename) was found to be 8.3 ⁇ m by volume.
  • the toner particles were mixed with 0.5 % of hydrophobic colloidal silica particles (BET-value 130 m/g).
  • non-invention toner II The preparation of non-invention toner II proceeded as described for non-invention toner I with the difference that said resin No. 1 was replaced in equal amounts by resin No. 3 of Table 1.
  • the solidified mass was pulverized and milled using an ALPINE Fliessbettarnastrahlmühle type 100AFG (tradename) and further classified using an ALPINE multiplex zig-zag classifier type 100MZR (tradename).
  • the average particle size of the separated toner was measured by Coulter Counter model Multisizer (tradename) was found to be 8.0 ⁇ m by volume.
  • the toner particles were mixed with 0.5 % of hydrophobic colloidal silica particles (BET-value 130 m/g).
  • Each of the above prepared toners I, II and III were used to form carrier-toner developers by mixing said mixture of toner particles and colloidal silica in a 4 % ratio with silicone-coated Cu-Zn ferrite carrier particles having an average diameter of 55 ⁇ m.
  • carrier toner-mixtures were used separately in an X-35 (tradename of Agfa-Gevaert N.V.) electrophotographic copier wherein the photoconductive drum was exposed to a step-wedge original.
  • X-35 tradename of Agfa-Gevaert N.V.
  • the standard hot roller fuser was removed, and the toner of the unfixed copy was non-contact fused by radiation using an infra-red black body radiant element placed at a distance of 10 mm from the copy paper carrying the toner image.
  • the copy paper passed-by the radiant element at a speed of 5 cm per second.
  • the average power provided to the radiant heating element was 375 W making the element operate at a temperature of 600 °C using reflectors to concentrate the radiant heat onto the copy paper.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Developing Agents For Electrophotography (AREA)

Abstract

L'invention concerne une poudre toner sèche dont les particules sont attirables de manière électrostatique ou magnétique et qui est appropriée pour être utilisée dans le développement satiné d'images à charge électrostatique ou de modèles magnétiques. Selon cette invention, la composition desdites particules de poudre comprend au moins une résine P thermoplastique transparente sensiblement incolore (fusible) et au moins un composé Q sensiblement incolore, caractérisée par le fait que ladite résine P et ledit composé Q, après avoir été mélangés à l'état fondu puis solidifiés, constituent une composition de surexposition qui, dans les conditions de mesure du test R, a une valeur d'absorption optique supérieure à 0,10 mais inférieure à 1,0, la ou les résines P et le ou les composés Q étant présents dans ledit toner dans une plage de rapport de poids P/Q de 5:1 à 1:5, et le rapport de poids entre P+Q et le poids total du toner est égal ou supérieur à 25:100.

Claims (10)

  1. Poudre de toner sec dont les particules de poudre sont sujettes à une attraction électrostatique ou magnétique et conviennent pour une utilisation dans le développement d'images de charge électrostatique ou de dessins magnétiques, et dans lesquelles lesdites particules de poudre renferment au moins une résine thermoplastique P transparente et au moins un composé Q, ledit composé Q ayant un caractère plus polaire que ladite résine P, caractérisé en ce que ladite résine P, au nombre d'au moins un, et ledit composé Q, au nombre d'au moins un, après avoir été mélangés dans l'état fondu, puis solidifiés, forment une composition diffusant la lumière qui, dans les conditions de mesure de l'essai R décrit dans la description, possède une valeur d'absorption optique corrigée supérieure à 0,10, mais pas supérieure à 1,0, ladite ou lesdites résines P et ledit ou lesdits composés Q étant présents, dans ledit toner, dans un rapport pondéral P/Q de 5:1 à 1:5, et le rapport pondéral de P + Q, rapporté au poids total du toner, est égal ou supérieur à 25:100.
  2. Poudre de toner sec selon la revendication 1, dans laquelle ledit rapport pondéral de P + Q rapporté au poids total du toner est égal ou supérieur à 75:100.
  3. Poudre de toner sec selon la revendication 1 ou 2, dans laquelle ledit rapport pondéral P/Q est de 3:1 à 1:3.
  4. Poudre de toner sec selon l'une quelconque des revendications 1 à 3, dans laquelle lesdites particules de poudre contiennent, comme résine P, une première résine A qui est une résine de polyester possédant une faible teneur (inférieure à 5,5 moles/kg) en groupes carbonyloxy (-CO.O-), et une seconde résine B qui est un polyester possédant une forte teneur (supérieure à 7,5 moles/kg) en groupes carbonyloxy.
  5. Poudre de toner sec selon la revendication 4, dans laquelle ladite résine A est dérivée d'un acide dicarboxylique non aromatique et d'un bisphénol A éthoxylé et/ou propoxylé, et ladite résine B est un polyester dérivé d'un acide dicarboxylique aromatique et d'un diol.
  6. Poudre de toner sec selon la revendication 5, dans laquelle, dans la production de ladite résine B, le diol est l'éthylèneglycol, éventuellement mélangé avec du bisphénol A éthoxylé et/ou propoxylé, pourvu que la teneur en éthylèneglycol de la totalité des diols soit supérieure à 50% en moles.
  7. Poudre de toner sec selon la revendication 5, dans laquelle ladite résine P est un polyester dérivé de l'acide fumarique et du bisphénol A dipropoxylé.
  8. Poudre de toner sec selon l'une quelconque des revendications 1 à 3, dans laquelle lesdites particules de poudre de toner contiennent, comme résine P, un polyester en combinaison avec un composé Q qui est une résine styrène-acrylique ayant une teneur en styrène relativement élevée (supérieure à 70% en moles).
  9. Poudre de toner sec selon la revendication 1, dans laquelle le composé Q est au moins un composé choisi parmi l'acide arachidique et le stéaramide.
  10. Poudre de toner sec selon l'une quelconque des revendications précédentes, dans laquelle ladite poudre de toner est incolore ou contient un colorant.
EP94918827A 1993-06-22 1994-05-30 Poudre toner attirable de maniere electrostatique et/ou magnetique Expired - Lifetime EP0656129B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP94918827A EP0656129B1 (fr) 1993-06-22 1994-05-30 Poudre toner attirable de maniere electrostatique et/ou magnetique

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
EP93201815 1993-06-22
EP93201815 1993-06-22
EP94918827A EP0656129B1 (fr) 1993-06-22 1994-05-30 Poudre toner attirable de maniere electrostatique et/ou magnetique
PCT/EP1994/001772 WO1995000883A1 (fr) 1993-06-22 1994-05-30 Poudre toner attirable de maniere electrostatique et/ou magnetique

Publications (2)

Publication Number Publication Date
EP0656129A1 EP0656129A1 (fr) 1995-06-07
EP0656129B1 true EP0656129B1 (fr) 1996-02-07

Family

ID=8213917

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94918827A Expired - Lifetime EP0656129B1 (fr) 1993-06-22 1994-05-30 Poudre toner attirable de maniere electrostatique et/ou magnetique

Country Status (4)

Country Link
EP (1) EP0656129B1 (fr)
JP (1) JPH08500913A (fr)
DE (1) DE69400072T2 (fr)
WO (1) WO1995000883A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0801333A3 (fr) * 1996-04-09 1998-01-07 Agfa-Gevaert N.V. Composition de toner
US5985503A (en) * 1997-03-11 1999-11-16 Agfa-Gevaert, N.V. Electrostatographic method for the production of transfer images
EP0864939A1 (fr) * 1997-03-11 1998-09-16 Agfa-Gevaert N.V. Méthode électrostatographique de production d'images transférables

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4518673A (en) * 1982-04-28 1985-05-21 Hitachi Metals, Ltd. Electrophotographic developer
JPS59164560A (ja) * 1983-03-08 1984-09-17 Kao Corp 圧力定着型トナ−組成物
SU1180830A1 (ru) * 1984-03-29 1985-09-23 Предприятие П/Я Г-4602 Способ получени электрографического жидкого про вител
US4908290A (en) * 1986-11-17 1990-03-13 Ricoh Company, Ltd. Toner for developing latent electrostatic images

Also Published As

Publication number Publication date
WO1995000883A1 (fr) 1995-01-05
DE69400072T2 (de) 1996-09-12
JPH08500913A (ja) 1996-01-30
EP0656129A1 (fr) 1995-06-07
DE69400072D1 (de) 1996-03-21

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