US3262806A - Three component magnetic developer for electrophotographic purposes and method for using it - Google Patents

Three component magnetic developer for electrophotographic purposes and method for using it Download PDF

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US3262806A
US3262806A US244251A US24425162A US3262806A US 3262806 A US3262806 A US 3262806A US 244251 A US244251 A US 244251A US 24425162 A US24425162 A US 24425162A US 3262806 A US3262806 A US 3262806A
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toner
acid
image
developer
component
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Gourge Gerhard
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Azoplate Corp
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Azoplate Corp
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    • 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
    • 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
    • G03G13/06—Developing
    • G03G13/08—Developing using a solid developer, e.g. powder developer
    • G03G13/09—Developing using a solid developer, e.g. powder developer using magnetic brush
    • 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
    • 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
    • G03G9/0906—Organic dyes
    • 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
    • G03G9/09708—Inorganic 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
    • 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
    • G03G9/10—Developers with toner particles characterised by carrier particles
    • G03G9/107—Developers with toner particles characterised by carrier particles having magnetic components
    • G03G9/1087—Specified elemental magnetic metal or alloy, e.g. alnico comprising iron, nickel, cobalt, and aluminum, or permalloy comprising iron and nickel
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S101/00—Printing
    • Y10S101/37—Printing employing electrostatic force

Definitions

  • the toners commonly used in electrophotography comprise natural or synthetic resins in finely divided powder form. When used for the development of latent electrostatic images, such a toner is mixed with somewhat larger particles-of a carrier which generally comprises an inorganic material, e.g. iron powder.
  • Iron powder is particularly effective as a carrier as it It has been suggested to use toners consisting of two components which have approximately the same grain sizes. One toner component acquires a positive charge during handling and the other toner component acquires a negative charge. The use of these toners gives particularly desirable results with respect to freedom from background and sharpness of images produced therewith.
  • the object of the present invention is a method for developing latent electrostatic images by means of a developer consisting of a carrier and toner, said developer being characterized in that the carrier consists of a magnetically excitable powder which is mixed with a toner consisting of at least two components of about equal grain sizes at least one of which accepts a positive charge and the other a negative charge and that this developer is taken up by a magnetic vdevice which serves as an applicator system for the developer and, simultaneously, as a bias electrode.
  • the present invention is further concerned with a material for performing the above described process, said material consisting of a carrier and a toner and being characterized in that the carrier consists of a magnetically excitable powder and the toner consists of at least two components of about equal grain sizes one of which accepts a positive charge and the other a negative charge.
  • the iron powder in the developer according to the invention does not participate with the toner components in the triboeiectri-c charging, but acts, in conjunction with a suitable magnetic applicator, as an applicator system and, if desired, also as a bias electrode.
  • the developer according to the invention enables a latent electrostatic image to be developed in such a way that fine lines and large solid areas are simultaneously given perfect development. At the same time, an image practically completely free of background is obtained.
  • the particle size of the iron powder is normally between 50 and 400 and preferably between 100 and 300
  • These two toner components are advantageously such that the toner or toners constituting the component of one polarity at least are soluble in Water, alkalis or acids and/or when heated decompose to yield volatile substances or substances readily soluble in these solvents.
  • Natural and synthetic resins such as colophony, copals, darnmar resin, asphalts, colophony-modified phenol resins, ketone resins, maleic resins, coumarone' resins, polyacrylic acid resins and polystyrenes are suitable for the toner component which assumes a positive charge. Mixtures of these resins may also be used. Inorganic and/or organic pigments and/ or dyestuffs may be added to these resins to impart to them a definite positive polarity. Examples of suitable substances are carbon black, zinc oxide, titanium dioxide, barium sulfate, minium and dyestuffs such as those listed in Schultzs Farbstofitabellen, vol. 1, 7th edition (1931). Also mixtures of such dyestuffs and/ or pigments may be used.
  • Minute quantities of these substances are often sufficient to impart a clearly positive character to the resins. It is also often advantageous to incorporate small uantities of waxes and/or organic compounds of low melting point and their substitution products, e.g. 0.1 to 10 percent, preferably 1 to 5 percent by weight, to the positive toner component to influence in a desirable direction its melting point and adhesive power.
  • Waxes suitable for this purpose include natural waxes such as carnauba wax, beeswax, Japan wax, montan wax, ceresine and synthetic waxes such as those marketed as A-wax, OP-wax, SPO-wax, V-wax, O-wax, E-wax, Hard WaxH, Hard Wax W, various waxes known as Ruhrwachse, and particularly the products available as Gersthofener waxes with the codings S, L, O, and OP.
  • natural waxes such as carnauba wax, beeswax, Japan wax, montan wax, ceresine
  • synthetic waxes such as those marketed as A-wax, OP-wax, SPO-wax, V-wax, O-wax, E-wax, Hard WaxH, Hard Wax W
  • various waxes known as Ruhrwachse and particularly the products available as Gersthofener wax
  • Suitable organic compounds of low melting point include, in particular, substituted and unsubstituted aromatic compounds having melting points between 40 and C., for example naphthols, such as l-naphthol and Z-naphthol, aromatic compounds such as acenaphthene, acylamino compounds such as acetanilide, halogen aromatic compounds such as p-dibromobenzene, amino compounds such as 2,4-diamino toluene, o-phenylene diamine, phenols such as resorcinol, and diphenylamine and derivatives thereof.
  • naphthols such as l-naphthol and Z-naphthol
  • aromatic compounds such as acenaphthene
  • acylamino compounds such as acetanilide
  • halogen aromatic compounds such as p-dibromobenzene
  • amino compounds such as 2,4-diamino tol
  • Metal resinates are particularly suitable as the toner component which acquires the negative charge.
  • Metal resinates also known as resin soaps, are resin acid salts of metals of the first to eighth groups of the Periodic System.
  • Resinates, and mixtures thereof, of aluminum, barium, lead, calcium, cerium, iron, cobalt, copper, magnesium, manganese and zinc are particularly suitable.
  • the negative toner component may include up to 50 percent by weight of r resins, such as those above specified for use in the positive toner component.
  • r resins such as those above specified for use in the positive toner component.
  • the above mentioned waxes and lowmelting organic compounds having melting points between 40 and 150 C. may also be added to the metal resinates.
  • Dyestuffs and pigments such as those described for use in the positive toner component'may also be added.
  • the content of pigments and dyestuffs should not exceed 10 percent of the metal resinates in order to assure preservation of the negative polarity, except in the case of dyestuffs containing metals, of which quantities of up to 50 percent, but preferably not more than 35 percent by weight, may be added.
  • dyestuffs containing metals are those which contain in the molecule metals such as copper, zinc, magnesium, iron, sodium or potassium bound in complex form, e.g. complexes such as chlorophyll or copper, zinc or magnesium phthalocyanine or Naphthol Green B. Also useful are double salts of dyestuff molecules, e.g. zinc chloride double salts. Complexes of heteropoly acids, such 3 as phosphoric/molybdic/tungstic acid with dyestuffs, may also be used.
  • Sulfonic acids and, in particular, carboxylic acids are suitable as alkli-soluble toners, e.g. oxalic acid, adipic acid, tartaric acid, 'benzoic acid, aminobenzoic acid, chlorobenzoic acid, naphthalic acid, 2-hydroxy-1-naphthoic acid, tetrachloropht-halic acid, anthraquinone carboxylic acid, benzene sulfonic acid, chlorobenzene sulfonic acid, naphthalene sulfonic acid, naphthol sulfonic acid, naphthylaminosulfonic acids, aminonaphthol sulfonic acids, benzi- 'dine sulfonic acids, anthracene sulfonic acids, anthraquinone sulfonic acids; and also acid anhydrides such as naphthalic anhydride and pht halic anhydride and
  • the alkali-soluble organic compounds may be used uncolored or they maybe colored wit-h the above-mentioned organic dyestuffs or organic or inorganic pigments.
  • propionic acid and butyric acid which also contain a certain proportion of unsaturated monocarboxylic acids such as crotonic acid and cinnamic acid or unsaturated dicarboxylic acids such as maleic acid, fumaric acid or itaconic acid can also be used as alkali-soluble toners.
  • unsaturated monocarboxylic acids such as crotonic acid and cinnamic acid
  • unsaturated dicarboxylic acids such as maleic acid, fumaric acid or itaconic acid
  • Styrene and maleic acid interpolymers and resins having a high acid number, e.g. over 150, and of which colophony forms the major part, can also be used.
  • Suitable acid-soluble toners are solid basic organic compounds such as phenylene diamine, benzidine, diphenylamine, naphthylamine, naphthylene diamine, 5,6-benzoquinoline, 5,6-benzoquinaldine, 4-chloroaniline, 4,4'-diamino-benzophenone and those of the triazole, imidazole and pyrazole compounds above named as alkali-soluble compounds and which, because of the presence of an NH group, are also acid-soluble.
  • the salts of the alkali-soluble toners are suitable, as also are the salts of the acid-soluble toners, particularly with strong inoragnic acids.
  • alkali metal salts of organic aliphatic, aromatic or heterocyclic carboxylic acids or sulphonic acids such as sodium acetate, lithium citrate, sodium/ potassium tartrate, sodium benzoate, the sodium salt of naphthalene-l-carboxylic acid, the disodium salt of naphthalene-1,5-disulfonic acid, the potassium salt of anthracene-l-sulfonic acid, the potassium salt of fluorene dicarboxylic acid and the sodium salt of 1-phenyl-5methy1 pyrazole carboxylic acid, water-soluble sulfonimides such as benzoic acid sulfimide and dibenzene sulfonylimide.
  • alkali metal salts of organic aliphatic, aromatic or heterocyclic carboxylic acids or sulphonic acids such as sodium acetate, lithium citrate, sodium/ potassium tartrate, sodium benzoate, the sodium salt of naphthalene-l-carboxylic acid,
  • Lower, water-soluble organic carboxylic acids, diand tricarboxylic acid and hydroxycarboxylic acids such as oxalic acid, succinic acid, adipic acid, maleic acid, tartaric acid, malic acid, citric aid, salicyclic and resorcyclic acid and water-soluble resins such as polyvinyl alcohols, polyvinyl pyrrolidones and low molecular weight condensation products of melamine-formaldehyde resins can also be used.
  • Readily decomposable carboxylic acids such as malonic acid, acetone dicarboxylic acid, citraconic acid and furfural malonic acid, in particular, maybe used as toners which decompose under the influence of heat.
  • the developer according to the invention may include at least one organic resin-type toner component which assumes a positive charge and at least one inorganic toner component which assumes a negative charge, the particle sizes being approximately equal.
  • Suitable inorganic toner components which assume a negative charge are salts such as potassium sulfate, calcium sulfate, ammonium chloride, sodium chloride, potassium bromide, copper sulfate, aluminum/potassium sulfate and sodium sulfate; oxides, e.g. iron oxide, titanium dioxide, zinc oxide, aluminum oxide and copper oxide; silicates, e.g. kieselguhr, silical gel, talcum and glass powder; borates, e.g. sodium mctab-orate and potassium borate; and carbonates such as calcium carbonate, magnesium carbonate and potassium carbonate.
  • salts such as potassium sulfate, calcium sulfate, ammonium chloride, sodium chloride, potassium bromide, copper sulfate, aluminum/potassium sulfate and sodium sulfate
  • oxides e.g. iron oxide, titanium dioxide, zinc oxide, aluminum oxide and copper oxide
  • silicates e.g.
  • the organic toner components are advantageously prepare as follows: the pulverized starting materials are ground together very finely; the mixture is heated to melting and stirred until a high degree of homogeneity is attained and the melt is then cooled. Alternatively, the fusible starting materials maybe liquified'by heating. The other components are then stirred in and the mixture is cooled. The resultant mass is finely ground and screened and, for the toner, screen fractions with an average particle size of about 1 to 100 preferably of about 10 to 30 are used.
  • the inorganic toner substances are likewise finely ground and screened and average particle sizes of about 1 to 100 preferably 1 to 10 and/or 10 to 20 are used.
  • the toner component which acquires a negative charge may be mixed with the one which acquires a positive charge in proportions of about 1:1 to 20:1 by weight. Approximately equal proportions of the two types of toner are preferable.
  • the developer may contain 1 part by weight of toner to 15-50 parts by weight of iron powder. Particularly good results are obtained with proportions of 1 part of toner to 15-25 parts by weight of iron powder.
  • a general principle is that with relatively fine iron powder, of particle size 50-100,, a larger quantity of toner is necessary than is required in a mixture with fairly coarse iron filings, e.g. of particle size 300-400u.
  • the developer may be withdrawn from a trough by means of a rotating magnetic roller and passed over the surface of the exposed photoconductive material.
  • the iron powder releases the toner and a visible image is formed, which may be fixed.
  • the quality of the image is influenced not only by the proportions of the components of the developer and the particle size of the iron powder but also by the type of magnetic applicator used.
  • magnetic brushes which are as soft as possible are used, e.g. those constituted by permanent or electrically excited bar magnets. These can be arranged in a plane or in radial formation on a rotating roll. Magnetic rolls excited by electrical windings in grooves parallel to the axis are also very suitable. Images free of background are obtained in which even very large solid image areas are homogeneously developed with a covering layer of developer. At the same time, the finest lines are sharply reproduced.
  • FIGURE 1 schematically illustrates a device for mag netic brush development using a bias electrode
  • FIGURE 2 schematically illustrates a device for magnetic brush development using a permanent electromagnetic roller.
  • a permanent magnet 1 has a plurality of brush-like bristles 2 of the developer mixture of the invention adhered thereto.
  • a battery 3, or other source of biasing voltage, is connected with the permanent magnet 11 and a supporting plate 4 of high conductivity.
  • An electrophotographic material 5, having a photoconductive layer on the top thereof and a latent electrostatic image on the photoconductive layer, is developed with positively charged toner in the image areas 6, and developed with the negatively charged toner in the image areas 6a.
  • a container 7 holds a quantity of .the developer mixture 8 of the invention and a battery or other source of biasing voltage 9 is connected with the axle of the permanent electromagnetic roller 14 and the supporting plate 10 of high conductivity.
  • the toner is applied to the latent electrostatic image by means of the brush-like bristles 13 of the developer mixture of the invention which are magnetically adhered to the roller 14.
  • photoconductors particularly organic photoconductors which can be charged both negatively and positively, positive images can be obtained from positive as well as from negative masters with the same toner.
  • the colored toner component of the developer acquires a positive charge, negative charging of the layer and exposure thereof behind a positive master will cause toner to become deposited in the image parts.
  • the same photoconductive coating is positively charged and exposed behind a negative master so that a latent image is first obtained in which the image parts are no longer charged while in the other parts the positive charge is preserved to a greater or lesser extent.
  • the colored, positively charged component of the toner must be caused to settle in the charge-free parts.
  • a positive bias voltage with respect to the conductive support of the photoconductive layer, is applied to the magnetic brush.
  • the positive toner particles are preferentially deposited on the charge-free parts while the other toner component of the developer settles on the positively charged parts of the latent image.
  • the level of the bias applied is determined by the potentials remaining after exposure in the image parts and the imagefree parts. If too low a bias is selected, insufficient toner is deposited on the image parts.
  • the photoconductive coating of which is soluble in alkalis, and a developer, the'toner of which acquires a positive charge and is likewise soluble in alkalis if a negative charge is applied to the photoconductive coating, a printing plate is obtained after development, fixing, and alkaline treatment which is a reversed image of the master.
  • a negative charge is applied to the photoconductive coating
  • the coating is given a positive charge and the process is in other respects the same.
  • an acid-soluble substance is used as the toner which assumes a negative charge
  • this developer can also be used for electrophotographic material the photoconductive coating of which is soluble in acids. If the coating isnegatively charged, direct images are obtained, while with positivecharging, reversed images are obtained.
  • the electrophotographic image After the electrophotographic image has been developed and fixed, it is converted into a printing plate by treatment with an alkaline or an acid liquid, according to the solubility properties of the photoconductive coating.
  • the image parts or the image-free parts. of the photoconductive coating including any toner or decomposition product thereof that may be present thereon, are washed away and the support is bared. It is made water-acceptant either during this treatment or by after-treatment.
  • the support may be bared by wiping with the liquid, e.g. with a soaked cotton pad, or the plate may be immersed in a bath of the liquid, or rolls or other mechanical devices may be used to apply the liquid.
  • the printing plate After the treatment with alkali or acid, the printing plate is rinsed down with water and inked up with greasy ink. When the plate has been set up in a machine, long be produced.
  • a toner mixture is used from which at least one toner can be easily'removed during or after fixing, it is possible for this effect to be exploited particularly in the case of printing plates.
  • two toners with quite widely differing softening or melting points e.g. with a difference in melting point'of 20 to 200 C., preferably 50 to 150 C. If the toner of higher melting point is used as the one which is later removed, this prevents broadening in the contours of the toner of lower melting point, so that there is a further increase in the sharpness of the printing plates.
  • the developers described are advantageously used for the development of printing plates from which one toner, together with a part of the coating, is to be removed. -It is also possible, particularly if one toner is colorless, for any other electrostatic image to be developed. It is immaterial by what means the electrostatic image has been produced, e.g. by the action of visible light, X-rays, UV or infra-red light on suitably sensitive layers or by direct electronic production of the image on an insulating layer or by the transfer of an electrostatic image to an insulating layer.
  • Example 1 20 par-ts by weight of iron powder having a range of particle size of IOU-150 are mixed with 1 part by weight of toner of average particle size 10-15
  • the toner use-d consists of two components:
  • the resultant developer in which toner component (a) acquires a negative charge and toner component (b) acquires a positive charge, is taken up from a trough by means of an electrically excited magnetic roll.
  • the magnetic brush constituted by the iron powder adhering to the roll and carrying the toner on its surface, is grounded.
  • This developer is brought, in this form, into contact with a latent electrostatic image on the surface of a photoconductive insulating layer supported on an aluminum foil which had been charged before exposure to 300 volts.
  • the black, positively charged toner component is attracted by the negatively charged image and the colorless, negative toner component is repelled by the image but adheres to the uncharged edges of the black image.
  • the image is fixed by heating to about 160 C.
  • the resultant smear-fast copy is free of background while the large-area solid image parts are homogeneously colored.
  • the image To convert the image into a printing plate, it is wiped over with a solution of 10 percent monoethanolamine, percent sodium silicate and 85 percent by weight polyethylene glycol. This alkaline solution dissolves the image-free parts of the coating and also the alkali-soluble toner adhering to the edges of the image. After a brief rinsing with water, the image is inked up with greasy ink and used for printing in an olfset machine. The plate has a long printing run and produces prints free from defects.
  • Example 2 25 parts by weight of iron powder having a range of particle size of 50-100 produced by a spraying process, are mixed with one part by weight of toner of average particle size -l5,u..
  • the toner consists of two components:
  • the developer so produced is used to develop a latent electrostatic image on an aluminum foil carrying a photoconductive insulating layer which had been charged to -300 volts and exposed imagewise by the contact process under a positive master and the image is fixed. A sharp and clearly defined image of the master is formed.
  • the latent electrostatic image could still be developed without background by means of this developer if a negative bias (about 80 volts) with regard to the support is applied to the magnetic brush during development.
  • the fixed toner image can be converted into a printing plate by wiping over with a solution containing, by weight, 0.5 percent monoethanolamine, 60 percent glycerine and 39.5 percent ethylene glycol. After being sprayed down with water, the image is inked up with greasy ink, after which printing can be performed. With a printing plate of this type, long runs are possible and the prints reproduce fine lines sharply and clearly.
  • Example 3 1 part by weight of a toner consisting of equal parts by weight of a finely pulverized 4-amino-anisole-Z-sulfonic acid and a colored interpolymer of vinyl chloride, vinyl acetate and maleic acid are mixed with 30 parts by weight of iron filings having an average particle size of 150- ZOO/1..
  • This developer is ,used as described in Example 1 and Example 2 to develop a latent electrostatic image on a photoconductive insulating coating supported on an aluminum foil produced by contact exposure behind a master after the insulator layer has been positively charged to 130 volts.
  • Example 4 parts by weight of iron powder, produced by a spray process and subsequent grinding and having a particle size range of 50 to 100 are mixed with 1 part by weight of a toner of an average particle size of 5l5 1.
  • the toner consists of two components:
  • a photoconductive insulating coating on a paper support of adequate electrical conductivity is charged to -340 volts and then imagewise exposed by the contact process under a negative master.
  • the resultant electrostatic latent image is made visible by applying the developer by a magnetic brush which is given a negative bias of -300 volts.
  • the resultant image is free of background.
  • the finest line drawings are exactly and sharply reproduced. Also, large solid areas of 100 cm. and more can be covered completely homogeneously and uniformly With toner particles.
  • Example 5 1 part by weight of the toner mentioned in Example 2, having a particle size of 10 to is mixed with parts by weight of iron filings having a particle size of 100 to 200 This developer is applied by a magnetic applicator to a latent electrostatic image, produced by the reflex process, on a zinc oxide coating supported on a paper foil. The developed toner image can be transferred to another surface to produce a copy which is a sharp and background-free reproduction of the master.
  • a method of developing an electrostatic latent image which comprises applying to the image a developer comprising a mixed toner the components of which are powders having approximately equal particle sizes, one component being capable of acquiring a positive charge and consisting essentially of resin, and the other component being capable of acquiring a negative charge and consisting essentially of an inorganic substance, and an iron powder carrier, and fixing the deposited resin powder.
  • a method of developing an electrostatic latent image which comprises applying to the image developer comprising a mixed toner the components of which are powders having approximately equal particle sizes, one component being capable of acquiring a positive charge and consisting essentially of resin, and the other component being capable of acquiring a negative charge and consisting essentially of an inorganic substance, and an iron powder carrier, by means of a magnetic device which serves also as a bias electrode, and fixing the deposited resin powder.
  • a method according to claim 2 in which the toner component capable of acquiring a positive charge is a mixture of a resin and a wax.
  • a method according to claim 2 in which the toner component capable of acquiring a positive charge is a mixture of a resin and an organic compound having a melting point in the range of about l50 C.
  • a method according to claim 2 in which the toner component capable of acquiring a negative charge is selected from the group consisting of inorganic silicates, metal oxides, and inorganic metal salts and inorganic ammonium salts.
  • soluble I component is selected from the group consisting of sulsoluble component is an alkali metal salt of an acid selected from the group consisting of sulfonic and carboxylic acids.
  • a method for the preparation of a printing plate which comprises developing an electrostatic latent image on a supported photoconductive coating by contacting the image with a developer comprising a mixed toner the components of which are powders having approximately equal particle sizes, one component being capable of acquiring a positive charge and consisting essentially of resin, and the other component being capable of acquiring a negative charge and consisting essentially of an inorganic substance, and an iron powder carrier, fixing the deposited resin powder and removing the photoconductive coating from the support in the resinfree areas.
  • a method for the preparation of a printing plate which comprises developing an electrostatic latent image on a supported photoconductive coating by contacting the image with a developer comprising a mixed toner the components of which are powders having approximately equal particle sizes, one component being capable of acquiring a positive charge and consisting essentially of resin, and the other component being capable of acquiring a negative charge and consisting essentially of an inorganic substance, and an iron powder carrier, by means of a magnetic device which serves also as a bias electrode, fixing the deposited resin powder and removing the photoconductive coating from the support in the resin-free areas.
  • An electrophotographic developer comprising a mixed toner the components of which are powders having approximately equal particle sizes, one component being capable of acquiring a positive charge and consisting essentially of resin, and the other component being capable of acquiring a negative charge and consisting essentially of an inorganic substance, and an iron powder carrier.
  • An electrophotographic developer according to claim 19 in which the toner component capable of acquiring a positive charge is a mixture of a resin and an organic compound having a melting point in the range of about 40-150 C.
  • An electrophotographic developer according to claim 19 containing 1 part by weight of toner to 15-50 parts by Weight of iron powder.

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  • Physics & Mathematics (AREA)
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  • Engineering & Computer Science (AREA)
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US244251A 1961-12-16 1962-12-13 Three component magnetic developer for electrophotographic purposes and method for using it Expired - Lifetime US3262806A (en)

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DEK45462A DE1219797B (de) 1961-12-16 1961-12-16 Elektrophotographischer Pulverentwickler

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US3262806A true US3262806A (en) 1966-07-26

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BE (1) BE626060A (xx)
CH (1) CH426492A (xx)
DE (1) DE1219797B (xx)
DK (1) DK121895B (xx)
GB (1) GB975694A (xx)
LU (1) LU42882A1 (xx)
NL (1) NL286305A (xx)
SE (1) SE308664B (xx)

Cited By (38)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3349703A (en) * 1967-04-24 1967-10-31 Interchem Corp Electrostatic printing with two groups of particles of same composition and different size
US3406137A (en) * 1965-04-29 1968-10-15 Xerox Corp Imaging material
US3436234A (en) * 1965-04-29 1969-04-01 Xerox Corp Duplicating ink
US3519461A (en) * 1969-09-02 1970-07-07 Burroughs Corp Electrostatic dipole printing
US3557691A (en) * 1968-06-25 1971-01-26 Owens Illinois Inc Electrostatic stencil printing process utilizing polyester-alkyd resin powder
US3592167A (en) * 1969-04-02 1971-07-13 Xerox Corp Apparatus for loading toner on a developing brush
US3613638A (en) * 1969-10-27 1971-10-19 Xerox Corp Materials for fibrous development member
US3808026A (en) * 1972-03-13 1974-04-30 Xerox Corp Liquid development of electrostatic latent image
US3850649A (en) * 1971-08-05 1974-11-26 Minnesota Mining & Mfg Latent image printing
US3881941A (en) * 1973-10-01 1975-05-06 Gen Electric Alkali metal polytungstate phosphors containing europium
US3884825A (en) * 1972-08-03 1975-05-20 Xerox Corp Imaging composition
US3885960A (en) * 1972-12-11 1975-05-27 Bell & Howell Co Method of development of liquid electrostatic images using an hydrophobic barrier liquid
US3895125A (en) * 1971-12-17 1975-07-15 Canon Kk Process of dry development for electrophotography
US3901698A (en) * 1971-12-10 1975-08-26 Rank Xerox Ltd Method of reversal development using two electrostatic developers
US3920453A (en) * 1972-01-28 1975-11-18 Addressograph Multigraph Method of electrostatic duplicating by image transfer
US3946671A (en) * 1972-09-28 1976-03-30 The Commonwealth Of Australia Electrostatic offset printing
US3958988A (en) * 1974-02-19 1976-05-25 A. B. Dick Company Photoconductors having improved sensitivity by presence of a like polar fields during imaging
US3965021A (en) * 1966-01-14 1976-06-22 Xerox Corporation Electrostatographic toners using block copolymers
US3983045A (en) * 1971-10-12 1976-09-28 Xerox Corporation Three component developer composition
US3990394A (en) * 1973-08-27 1976-11-09 Konishiroku Photo Industry Co., Ltd. Control circuit used in development of electrostatic latent images and developing apparatus
US4115289A (en) * 1973-08-02 1978-09-19 A. B. Dick Company Dry powdered or liquid developer compositions
US4135927A (en) * 1970-05-20 1979-01-23 Xerox Corporation Multicolor xerographic process
US4149487A (en) * 1977-08-30 1979-04-17 Xerox Corporation Xerographic machine with infinitely variable developer bias
US4165393A (en) * 1975-11-26 1979-08-21 Ricoh Co., Ltd. Magnetic brush developing process for electrostatic images
US4187329A (en) * 1969-03-24 1980-02-05 International Business Machines Corporation Electrophotographic developing process and compositions for use therein
US4220699A (en) * 1977-06-03 1980-09-02 Ricoh Co., Ltd. Method for producing a large number of copies by means of copying apparatus
US4239845A (en) * 1978-03-09 1980-12-16 Minolta Camera Kabushiki Kaisha Electrophotographic copying method using two toners on magnetic brush
US4256820A (en) * 1978-05-22 1981-03-17 Savin Corporation Method of electrophotography using low intensity exposive
US4284701A (en) * 1977-11-03 1981-08-18 International Business Machines Corporation Electrophotographic toner of specific size distribution
US4301228A (en) * 1979-12-26 1981-11-17 Minolta Camera Kabushiki Kaisha Electrographic developing material and developing method employing said developing material
US4350749A (en) * 1978-02-28 1982-09-21 Ricoh Company Ltd. Reverse development method
US4367275A (en) * 1979-06-15 1983-01-04 Dainippon Ink & Chemicals, Inc. Method of preventing offset of electrostatic images after fixing and developing using polyvalent metal salt polymer in toner
US4404270A (en) * 1980-05-22 1983-09-13 Hitachi Chemical Company, Ltd. Positively chargeable powdered electrophotographic toner containing dialkyl tin oxide charge control agent
US4407925A (en) * 1981-03-13 1983-10-04 Xerox Corporation Process for developing electrostatic images with magnetic toner
US4469624A (en) * 1982-05-20 1984-09-04 Asahi Kasei Kogyo Kabushiki Kaisha Magnetic coating compositions for magnetic recording materials
US4522484A (en) * 1978-05-22 1985-06-11 Savin Corporation Electrophotographic apparatus for increasing the apparent sensitivity of photoconductors
US4525447A (en) * 1982-11-08 1985-06-25 Minolta Camera Kabushiki Kaisha Image forming method using three component developer
US5061964A (en) * 1990-07-20 1991-10-29 Xerox Corporation Developer unit using magnetic toner particles

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL159795C (xx) * 1968-07-22 Minnesota Mining & Mfg
CA1147192A (en) * 1978-04-06 1983-05-31 John L. Webb Electrostatographic developer including toner of diameter between 3 and 15 microns and carrier of diameter between 15 and 65 microns

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US2297691A (en) * 1939-04-04 1942-10-06 Chester F Carlson Electrophotography
US2618551A (en) * 1948-10-20 1952-11-18 Haloid Co Developer for electrostatic images
US2786440A (en) * 1953-06-30 1957-03-26 Rca Corp Electrophotographic developing apparatus
US2851373A (en) * 1955-11-21 1958-09-09 Bruning Charles Co Inc Developing electrostatic latent images on photo-conductive insulating material
US2874063A (en) * 1953-03-23 1959-02-17 Rca Corp Electrostatic printing
US2880696A (en) * 1956-05-02 1959-04-07 Haloid Xerox Inc Apparatus for developing an electrostatic latent image
US2890968A (en) * 1955-06-02 1959-06-16 Rca Corp Electrostatic printing process and developer composition therefor
US2919247A (en) * 1954-12-23 1959-12-29 Haloid Xerox Inc Tripartite developer for electrostatic images
CA608901A (en) * 1960-11-15 A. Metcalfe Kenneth Emulsion developers for electrostatic images
US2986521A (en) * 1958-03-28 1961-05-30 Rca Corp Reversal type electroscopic developer powder
US3013890A (en) * 1958-07-08 1961-12-19 Xerox Corp Process of developing electrostatic images and composition therefor
US3041165A (en) * 1956-07-04 1962-06-26 Kalle Ag Electrophotographic material
US3060051A (en) * 1958-11-25 1962-10-23 Rca Corp Method of fusing powder images
US3083117A (en) * 1957-06-14 1963-03-26 Schmiedel Ulrich Process of developing electrostatic images
US3093039A (en) * 1958-05-12 1963-06-11 Xerox Corp Apparatus for transferring powder images and method therefor
US3165420A (en) * 1959-06-27 1965-01-12 Azoplate Corp Developer for electrophotographic purposes and process for developing an electrostatic image

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BE546297A (xx) * 1955-03-23
DE1067305B (xx) * 1957-01-18 1959-10-15

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CA608901A (en) * 1960-11-15 A. Metcalfe Kenneth Emulsion developers for electrostatic images
US2297691A (en) * 1939-04-04 1942-10-06 Chester F Carlson Electrophotography
US2618551A (en) * 1948-10-20 1952-11-18 Haloid Co Developer for electrostatic images
US2874063A (en) * 1953-03-23 1959-02-17 Rca Corp Electrostatic printing
US2786440A (en) * 1953-06-30 1957-03-26 Rca Corp Electrophotographic developing apparatus
US2919247A (en) * 1954-12-23 1959-12-29 Haloid Xerox Inc Tripartite developer for electrostatic images
US2890968A (en) * 1955-06-02 1959-06-16 Rca Corp Electrostatic printing process and developer composition therefor
US2851373A (en) * 1955-11-21 1958-09-09 Bruning Charles Co Inc Developing electrostatic latent images on photo-conductive insulating material
US2880696A (en) * 1956-05-02 1959-04-07 Haloid Xerox Inc Apparatus for developing an electrostatic latent image
US3041165A (en) * 1956-07-04 1962-06-26 Kalle Ag Electrophotographic material
US3083117A (en) * 1957-06-14 1963-03-26 Schmiedel Ulrich Process of developing electrostatic images
US2986521A (en) * 1958-03-28 1961-05-30 Rca Corp Reversal type electroscopic developer powder
US3093039A (en) * 1958-05-12 1963-06-11 Xerox Corp Apparatus for transferring powder images and method therefor
US3013890A (en) * 1958-07-08 1961-12-19 Xerox Corp Process of developing electrostatic images and composition therefor
US3060051A (en) * 1958-11-25 1962-10-23 Rca Corp Method of fusing powder images
US3165420A (en) * 1959-06-27 1965-01-12 Azoplate Corp Developer for electrophotographic purposes and process for developing an electrostatic image

Cited By (38)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3406137A (en) * 1965-04-29 1968-10-15 Xerox Corp Imaging material
US3436234A (en) * 1965-04-29 1969-04-01 Xerox Corp Duplicating ink
US3965021A (en) * 1966-01-14 1976-06-22 Xerox Corporation Electrostatographic toners using block copolymers
US3349703A (en) * 1967-04-24 1967-10-31 Interchem Corp Electrostatic printing with two groups of particles of same composition and different size
US3557691A (en) * 1968-06-25 1971-01-26 Owens Illinois Inc Electrostatic stencil printing process utilizing polyester-alkyd resin powder
US4187329A (en) * 1969-03-24 1980-02-05 International Business Machines Corporation Electrophotographic developing process and compositions for use therein
US3592167A (en) * 1969-04-02 1971-07-13 Xerox Corp Apparatus for loading toner on a developing brush
US3519461A (en) * 1969-09-02 1970-07-07 Burroughs Corp Electrostatic dipole printing
US3613638A (en) * 1969-10-27 1971-10-19 Xerox Corp Materials for fibrous development member
US4135927A (en) * 1970-05-20 1979-01-23 Xerox Corporation Multicolor xerographic process
US3850649A (en) * 1971-08-05 1974-11-26 Minnesota Mining & Mfg Latent image printing
US3983045A (en) * 1971-10-12 1976-09-28 Xerox Corporation Three component developer composition
US3901698A (en) * 1971-12-10 1975-08-26 Rank Xerox Ltd Method of reversal development using two electrostatic developers
US3895125A (en) * 1971-12-17 1975-07-15 Canon Kk Process of dry development for electrophotography
US3920453A (en) * 1972-01-28 1975-11-18 Addressograph Multigraph Method of electrostatic duplicating by image transfer
US3808026A (en) * 1972-03-13 1974-04-30 Xerox Corp Liquid development of electrostatic latent image
US3884825A (en) * 1972-08-03 1975-05-20 Xerox Corp Imaging composition
US3946671A (en) * 1972-09-28 1976-03-30 The Commonwealth Of Australia Electrostatic offset printing
US3885960A (en) * 1972-12-11 1975-05-27 Bell & Howell Co Method of development of liquid electrostatic images using an hydrophobic barrier liquid
US4115289A (en) * 1973-08-02 1978-09-19 A. B. Dick Company Dry powdered or liquid developer compositions
US3990394A (en) * 1973-08-27 1976-11-09 Konishiroku Photo Industry Co., Ltd. Control circuit used in development of electrostatic latent images and developing apparatus
US3881941A (en) * 1973-10-01 1975-05-06 Gen Electric Alkali metal polytungstate phosphors containing europium
US3958988A (en) * 1974-02-19 1976-05-25 A. B. Dick Company Photoconductors having improved sensitivity by presence of a like polar fields during imaging
US4165393A (en) * 1975-11-26 1979-08-21 Ricoh Co., Ltd. Magnetic brush developing process for electrostatic images
US4220699A (en) * 1977-06-03 1980-09-02 Ricoh Co., Ltd. Method for producing a large number of copies by means of copying apparatus
US4149487A (en) * 1977-08-30 1979-04-17 Xerox Corporation Xerographic machine with infinitely variable developer bias
US4284701A (en) * 1977-11-03 1981-08-18 International Business Machines Corporation Electrophotographic toner of specific size distribution
US4350749A (en) * 1978-02-28 1982-09-21 Ricoh Company Ltd. Reverse development method
US4239845A (en) * 1978-03-09 1980-12-16 Minolta Camera Kabushiki Kaisha Electrophotographic copying method using two toners on magnetic brush
US4256820A (en) * 1978-05-22 1981-03-17 Savin Corporation Method of electrophotography using low intensity exposive
US4522484A (en) * 1978-05-22 1985-06-11 Savin Corporation Electrophotographic apparatus for increasing the apparent sensitivity of photoconductors
US4367275A (en) * 1979-06-15 1983-01-04 Dainippon Ink & Chemicals, Inc. Method of preventing offset of electrostatic images after fixing and developing using polyvalent metal salt polymer in toner
US4301228A (en) * 1979-12-26 1981-11-17 Minolta Camera Kabushiki Kaisha Electrographic developing material and developing method employing said developing material
US4404270A (en) * 1980-05-22 1983-09-13 Hitachi Chemical Company, Ltd. Positively chargeable powdered electrophotographic toner containing dialkyl tin oxide charge control agent
US4407925A (en) * 1981-03-13 1983-10-04 Xerox Corporation Process for developing electrostatic images with magnetic toner
US4469624A (en) * 1982-05-20 1984-09-04 Asahi Kasei Kogyo Kabushiki Kaisha Magnetic coating compositions for magnetic recording materials
US4525447A (en) * 1982-11-08 1985-06-25 Minolta Camera Kabushiki Kaisha Image forming method using three component developer
US5061964A (en) * 1990-07-20 1991-10-29 Xerox Corporation Developer unit using magnetic toner particles

Also Published As

Publication number Publication date
DE1219797B (de) 1966-06-23
CH426492A (de) 1966-12-15
BE626060A (xx)
NL286305A (xx)
SE308664B (xx) 1969-02-17
GB975694A (en) 1964-11-18
LU42882A1 (xx) 1963-02-15
DK121895B (da) 1971-12-13

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