WO1992022017A1 - Procede de formation d'images fixes - Google Patents

Procede de formation d'images fixes Download PDF

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Publication number
WO1992022017A1
WO1992022017A1 PCT/JP1992/000668 JP9200668W WO9222017A1 WO 1992022017 A1 WO1992022017 A1 WO 1992022017A1 JP 9200668 W JP9200668 W JP 9200668W WO 9222017 A1 WO9222017 A1 WO 9222017A1
Authority
WO
WIPO (PCT)
Prior art keywords
toner
isocyanate
fixing
recording medium
isothiocyanate
Prior art date
Application number
PCT/JP1992/000668
Other languages
English (en)
Inventor
Shin-Ichiro Yasuda
Kuniyasu Kawabe
Mitsuhiro Sasaki
Original Assignee
Kao Corporation
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
Priority claimed from JP15529691A external-priority patent/JPH04353885A/ja
Priority claimed from JP3155297A external-priority patent/JPH04353863A/ja
Application filed by Kao Corporation filed Critical Kao Corporation
Publication of WO1992022017A1 publication Critical patent/WO1992022017A1/fr

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/14—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base
    • G03G15/16—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer
    • G03G15/1695—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer with means for preconditioning the paper base before the transfer
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
    • G03G15/24—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 whereby at least two steps are performed simultaneously
    • 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
    • G03G9/08795—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775 characterised by their chemical properties, e.g. acidity, molecular weight, sensitivity to reactants
    • 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
    • G03G9/093—Encapsulated toner particles
    • G03G9/09307—Encapsulated toner particles specified by the shell material
    • G03G9/09314—Macromolecular compounds
    • G03G9/09328—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds

Definitions

  • the present invention relates to a method of forming fixed images used for plain paper copying machines, laser printers, plain paper facsimiles, etc. More particularly, it relates to a method of forming images in which transfer and fixing are simultaneously carried out using a recording medium whose surface is heated in advance.
  • Figure 3 shows a schematic view of an apparatus used in a conventional method of forming fixed images using an electrophotographic process.
  • the conventional method after an electrostatic latent image formed on a photoconductor by optical means is developed in a developing process, it is transferred to a recording medium such as a recording paper in a transfer process and then fixed into the final image generally with heat and pressure in a fixing process.
  • a cleaning device is provided for cleaning the residual toner after the transfer process with its rotation.
  • an electrostatic recording process comprises forming an electrostatic latent image by applying a signal voltage via a recording needle on an electrostatic recording sheet such as a recording paper; developing the electrostatic latent image using a developer device such as a magnetic brush; and transferring and fixing the electrostatic latent image by such means of heat, pressure, etc.
  • the toner is adhered to the recording medium in excessive portions at the time of developing, causing so-called "greasing," and foreign materials such as paper powders are adhered to the recording needle at the time of applying voltage directly to the recording paper via the recording needle, making it less likely to obtain a normal image. Accordingly, it still has been difficult to obtain a stable, high-quality image continuously.
  • the toner is adhered to the recording medium such as a recording paper in excessive portions at the time of developing, making it likely to cause "greasing.”
  • the recording medium such as a recording paper
  • various problems have been pointed out. From these standpoints, the development of a novel method of forming fixed images and a matching toner thereto is in demand.
  • An object of the present invention is to provide a novel method of forming fixed images, wherein transferring and fixing are simultaneously carried out onto the preheated recording medium, so that the fixing takes place only with a pressure roller, and practically all of the toner is transferred and fixed to the recording medium in the transfer and fixing process, thus providing only a trace amount of the toner lost and a little toner disposed, which makes the toner disposal box and its cleaning process simple and the resulting apparatus extremely compact. Therefore, in view of solving the above-mentioned problems, the present inventors have investigated a toner shell material which is fragile to heat at a low temperature.
  • the method of forming fixed images of the present invention comprises forming an electrostatic latent image; developing the electrostatic latent image, whereby a toner is applied to the electrostatic latent image to form a visible image; and simultaneously transferring and fixing the formed visible image onto a preheated recording medium.
  • the preheating temperature of the recording medium is in the range of not less than 50°C and not more than 160°C .
  • the visible image formed in the developing process is simultaneously transferred and fixed to the recording medium whose surface is heated in advance. Therefore, the transfer and fixing process can be remarkably simplified, and the radiator can be made much smaller due to its low fixing temperature, thereby achieving the miniaturization of an image-forming apparatus.
  • Figure 1 is a schematic view of an apparatus used in the method of forming fixed images as defined by the present invention using an electrophotographic process
  • Figure 2 is a schematic view of an apparatus used in the method of forming fixed images as defined by the present invention using an electrostatic recording process
  • Figure 3 is a schematic view of an apparatus used for conventional methods of forming fixed images
  • Figure D is a schematic view showing the charging process in the method as defined by the present invention using the electrophotographic process
  • Figure 5 is a schematic view showing the exposing process in the method as defined by the present invention using the electrophotographic process
  • Figure 6 is a schematic view showing the developing process in the method as defined by the present invention using the electrophotographic process.
  • Figure 7 is a schematic view showing the transfer and fixing process in the method as defined by the present invention using the electrophotographic process.
  • Element 1 is a photoconductor, element 1a a photoconductive layer, element lb a conductive supporter, element 2 an exposure device, element 3 a developer device, element 3a a rotating sleeve, element H a heater, element 5a a pressure roller, element 5b is a transfer device, element 6 a recording medium (a recording paper), element 7 a charger, element 8 a cleaner device, element 8a a toner collecting box, element 9 a charge eraser, element 10 a toner, element 12 a fixing roller, element 14 a heat roller, element 21 a voltage-applying device, element 22 a charge-remover, element 23 a developer device, element 2U a heater, element 25 a pressure roller, element 26 a recording medium, element 27 an insulating endless film belt, element 28 a cleaning web, element 29 a toner and element 30 a holding roller.
  • the toner used in the present invention is a thermally dissociating encapsulated toner.
  • the encapsulated toner according to the present invention comprises a heat-fusible core containing at least a coloring agent and a shell formed thereon so as to cover the surface of the core material.
  • the thermally dissociating encapsulated toner means a toner which comprises a shell whose structure is fragile to heat, and a core material which can be fixed at a low temperature by pressure. More particularly, the shell structure changes with heat, and at the point when pressure is applied, the core material is discharged to effect the fixing of the toner.
  • the toner in the present invention is a thermally dissociating encapsulated toner, and any toner whose fixing temperature is maintained in the range of HO to 120 ⁇ C to the recording medium such as a recording paper can be properly chosen.
  • phase separation is conducted around the core material.
  • a simple emulsion is first prepared, which in turn is converted to a complex emulsion, in which the core materials are micro-encapsulated.
  • a core material solution or dispersion is dispersed in a water in oil or oil in water type emulsion system, while at the same time shell material monomers (A) are collected around the surfaces, where in the next method, monomers (A) and monomers (B) react.
  • M Other methods include an in-situ polymerization method, a submerged cure coating method, an air suspension coating method, an electrostatic coalescing method, a vacuum vapor deposition coating method, etc.
  • the particularly preferred toner include those produced by the interfacial polymerization method and the spray-drying method. While the spray-drying method has the merits of an easy function separation for the core material and shell material and a large choice of shell materials, the interfacial polymerization method not only has the merit of an easy function separation for the core material and shell material but also is capable of producing a uniform toner in an aqueous state. Moreover, substances of low softening points can be used for the core material in the interfacial polymerization method, making it particularly suitable from the aspect of fixing ability.
  • the thermally dissociating encapsulated toner produced by the interfacial polymerization method among others is particularly preferred
  • shell materials styrene resins (Japanese Patent Laid-Open No.205162/1983), polyamide resins (Japanese Patent Laid-Open No.66948/1983) .
  • epoxy resins Japanese Patent Laid-Open No.148066/1984
  • polyurethane resins Japanese Patent Laid-Open No.179860/1982
  • polyurea resins Japanese Patent Laid-Open No.150262/1987) and many others have been proposed.
  • thermoplastic resins having glass transition points (Tg) of between 10°C and 50°C such as polyester resins, polyamide resins, polyester-polyamide resins and vinyl resins can be used.
  • Tg glass transition points
  • the structure and the thermal properties of the shell material concern themselves remarkably with the fixing ability of the entire toner. Since a particular polyurethane resin among the above-mentioned resins for the shell materials is thermally dissociating, having excellent storage stability and fixing ability at a low temperature, it is an extremely favorable material for the method of forming fixed images of the present invention.
  • thermoly dissociating encapsulated toner suitably used in the present invention can be produced by any known methods such as interfacial polymerization, etc., and this encapsulated toner is composed of a heat-fusible core material containing at least a coloring agent and a shell formed thereon so as to cover the surface of the core material, wherein the main components of the shell are a resin prepared by reacting:
  • the thermally dissociating linkage is preferably one formed by the reaction between a phenolic hydroxyl and/or thiol group and an isocyanate and/or isothiocyanate group.
  • Examples of the monovalent isocyanate compounds to be used as the the component (1) in the present invention include ethyl isocyanate, octyl isocyanate, 2-chloroethyl isocyanate, chlorosulfonyl isocyanate, cyclohexyl isocyanate, n-dodecyl isocyanate, butyl isocyanate, n-hexyl isocyanate, lauryl isocyanate, phenyl isocyanate, m-chlorophenyl isocyanate, 4-chlorophenyl isocyanate, p-cyanophenyl isocyanate, 3,4-dichlorophenyl isocyanate, o-tolyl isocyanate, m-tolyl isocyanate, p-tolyl isocyanate, p-toluenesulfonyl isocyanate, 1-naphthyl isocyanate, o
  • divalent or higher isocyanate compounds to be used as the component (2) in the present invention include aromatic isocyanate compounds such as 2,4-tolylene diisocyanate, 2,4-tolylene diisocyanate dimer, 2,6-tolylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, 4,4' -diphenylmethane diisocyanate, 1,5- naphthylene diisocyanate, 3,3'-dimethyldiphenyl-4,4 1 - diisocyanate, 3.3'-dimethyldiphenylmethane-4,4 1 -diisocyanate, m-phenylene diisocyanate, triphenylmethane triisocyanate and polymethylenephenyl isocyanate; aliphatic isocyanate compounds such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate,
  • isothiocyanate compounds examples include phenyl isothiocyanate, xylylene-1 ,4-diisothiocyanate and ethylidene diisothiocyanate.
  • isocyanate and isothiocyanate compounds compounds having an isocyanate group directly bonded to an aromatic ring are preferred, because they are effective in forming a urethane resin having a low thermal dissociation temperature.
  • the monovalent isocyanate and/or isothiocyanate compound (1) also serves as a molecular weight modifier for the shell-forming resin and • can be used in an amount of at most 30 mol % based on the isocyanate component and/or the isothiocyanate component. When the amount exceeds 30 mol % , the storage stability of the obtained encapsulated toner is undesirably poor.
  • Examples of compounds having one active hydrogen atom reactive with isocyanate and/or isothiocyanate groups to be used as component (3) in the present invention include aliphatic alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, tert-butyl alcohol, pentyl alcohol, hexyl alcohol, cyclohexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, lauryl alcohol and stearyl alcohol; aromatic alcohols such as phenol, o-cresol, m-cresol, p-cresol, 4-butylphenol, 2-sec-butylphenol,
  • a phenol derivative represented by the following formula (I) is preferably used:
  • Ru and R 5 each independently represents a hydrogen atom, an alkyl group having 1 to 9 carbon atoms, an alkenyl, alkoxy, alkanoyl, carboalkoxy or aryl group or a halogen atom.
  • Examples of the dihydric or higher alcohols among the compounds having at least two active hydrogen atoms reactive with isocyanate and/or isothiocyanate groups to be used as the component (4) in the present invention include catechol, resorcinol, hydroquinone, 4-methylcatechol, 4-tert- butylcatechol, 4-acetylcatechol, 3-methoxycatechol, 4-phenylcatechol , 4-methylresorcinol, 4-ethylresorcinol , 4-tert-butylresorcinol, 4-hexylresorcinol, 4-chlororesorcinol, 4-benzylresorcinol, 4-acetylresorcinol, 4-carbomethoxyresorcinol, 2-methylresorcinol,
  • catechol derivatives reprsented by the following formula (II) and resorcinol derivatives represented by the following formula (III) are preferably used:
  • Re and R g each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl, alkoxy, alkanoyl, carboalkoxy or aryl group or a halogen atom.
  • Ri 0 . R_ ⁇ . R ⁇ 2 and Ri 3 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl, alkoxy, alkanoyl, carboalkoxy or aryl group or a halogen atom.
  • examples of the compounds having at least one isocyanate- or isothiocyanate-reactive functional group other than the hydroxyl group and at least one phenolic hydroxyl group include o-hydroxybenzoic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, 5-bromo-2- hydroxybenzoic acid, 3-chloro-4-hydroxybenzoic acid, 4-chloro-2-hydroxybenzoic acid, 5-chloro-2-hydroxybenzoic acid, 3.5-dichloro-4-hydroxybenzoic acid, 3-methyl-2- hydroxybenzoic acid, 5-methoxy-2-hydroxybenzoic acid, 3,5-di-tert-butyl-4-hydroxybenzoic acid, 4-amino-2- hydroxybenzoic acid, 5-amino-2-hydroxybenzoic acid, 2,5- dinitrosa ⁇ icylic acid, sulfosalicylic acid, 4-hydroxy-3- ethoxyphenylacetic acid, catechol-4-carboxylic acid, 2,4- di
  • examples of the polythiol compounds having at least one thiol group in each molecule include ethanethiol, 1-propanethiol, 2-propanethiol, thiophenol, bis(2- mercaptoethyl) ether, 1 ,2-ethanedithiol, 1 ,4-butanedithiol , bis(2-mercaptoethyl) sulfide, ethylene glycol bis(2- mercaptoacetate) , ethylene glycol bis(3-mercaptopropionate) , 2,2-dimethylpropanediol bis(2-mercaptoacetate) , 2,2- dimethylpropanediol bis(3-mercaptopropionate) , trimethylolpropane tris(2-mercaptoacetate) , trimethylolpropane tris(3-mercaptopropionate) , trimethylolethane tris(2-mercaptoacetate) , trimethylolethane tri
  • thermally dissociating shell-forming resin used in the present invention at least 30%, perferably at least 50% of all of the linkages formed from isocyanate or isothiocyanate groups are thermally dissociating linkages.
  • content of the thermally dissociating linkages is less than 30%, the strength of the shell in the heat-and- pressure fixing cannot be sufficiently lowered, making it less likely to exhibit any advantageous fixing performance of the core material.
  • other compounds having an isocyanate- reactive functional group other than phenolic hydroxyl and thiol groups which may be used as a shell-forming material in such an amount as not to lower the ratio of the linkages formed by the reaction of isocyanate and/or isothiocyanate groups with phenolic hydroxyl and/or thiol groups to the all of the linkages formed from isocyanate and/or isothiocyanate groups is less than 30%, include, for example, the following active methylene compounds such as malonate and acetoacetate, oxime such as methyl ethyl ketone oxime, carboxylic acid, polyol, polyamine, aminocarboxylic acid and aminoalcohol.
  • the compound having one active hydrogen atom reactive with isocyanate and/or. isothiocyanate groups as the component (3) may be used in an amount of at most 30 mol % based on the active hydrogen component. When the amount exceeds 30 mol %, the storage stability of the resulting toner is undesirably poor.
  • the molar ratio of (A) the isocyanate compound and/or isothiocyanate compound comprising the components (1) and (2) to (B) the active hydrogen compounds comprising the components (3) and (4) preferably lies between 1:1 and 1:20 in order to obtain a resin free from unreacted isocyanate groups.
  • the shell is preferably formed by an interfacial polymerization or an in-situ polymerization.
  • it may be formed by a dry method comprising stirring in an air stream at a high rate matrix particles used as a core material together with particles used as a shell-forming material having a number-average particle size of one-eighth or less of that of the matrix particles.
  • the resins to be used as core materials of the encapsulated toner according to the present invention are thermoplastic resins having glass transition points (Tg) of 10 to 50 ⁇ C , and examples thereof include polyester resins, polyester-polyamide resins, polyamide resins and vinyl resins, among which vinyl resins are particularly preferable.
  • Tg glass transition point
  • the glass transition point (Tg) is less than 10°C , the storage stability of the resulting encapsulated toner is undesirably poor, and when it exceeds 50°C , the fixing strength of the encapsulated toner is undesirably poor.
  • Examples of the monomers constituting the vinyl resins include styrene and its derivatives such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, -methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-chlorostyrene and vinylnaphthalene; ethylenically unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; vinyl esters such as vinyl chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propionate, vinyl formate and vinyl caproate; ethylenic monocarboxylic acids and esters thereof such as acrylic acid, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobuty
  • the core material- orming resin contains, in the main skeleton of the resin, styrene or its derivatives preferably in an amount of 50 to 90 parts by weight, and the ethylenic monocarboxylic acid or an ester thereof preferably in an amount of 10 to 50 parts by weight to control the thermal properties of the resin, such as the softening point.
  • the monomer composition constituting the core material-forming resin according to the present invention contains a crosslinking agent, which may be also used, if necessary, as a mixture of two or more of them, any known crosslinking agents may be properly used.
  • a crosslinking agent which may be also used, if necessary, as a mixture of two or more of them, any known crosslinking agents may be properly used.
  • the amount of the crosslinking agent added is too large, the resulting toner is less likely to be heat-fused, thereby resulting in poor heat fixing ability and heat-and-pressure fixing ability.
  • the amount is too small, in heat-and-pressure fixing, a part of the toner cannot be completely fixed on a paper but rather adheres to the surface of a roller, which in turn is transferred to a subsequent paper which creates the so-called "offset” or "offset phenomenon”.
  • the amount of the crosslinking agent is preferably 0.001 to 15% by weight, more preferably 0.1 to 10% by weight, based on the monomers used.
  • the core material of the thermally dissociating encapsulated toner according to the present invention may further contain, if necessary, one or more offset inhibitor of any known kind for the purpose of improving offset resistance at heat-and-pressure fixing. These offset inhibitors are contained in an amount of 1 to 20% by weight based on the resin contained in the core material.
  • the core material of the thermally dissociating encapsulated toner according to the present invention contains a coloring agent, which may be any one of the dyes and pigments used in the conventional toners.
  • the coloring agent is generally contained in an amount of 1 to 15 parts by weight per 100 parts by weight of the resin contained in the core material.
  • a metal- containing dye which has been used for toners for example, a metal complex of an organic compound having a carboxyl or nitrogenous group, such as nigrosine, may be added in an effective amount as a charge control agent.
  • a charge control agent may be mixed with the toner.
  • the thermally dissociating encapsulated toner according to the present invention may contain, if necessary, a fluidity improver and/or a cleanability improver.
  • an additive for example, finely powdered polymethyl methacrylate, etc. may be added.
  • a small amount of carbon black may be used.
  • the thermally dissociating encapsulated toner of the present invention preferably has a softening point of 80 to
  • the particle size of the encapsulated toner according to the present invention is not particularly limited, the average particle size thereof is generally 3 to 30 ju m.
  • the preferred thickness of the shell of the encapsulated toner is from 0.01 to 1 ⁇ m. When the thickness ⁇ is less than 0.01 ⁇ . m , the blocking resistance of the resulting encapsulated toner is poor, and when it exceeds 1 ⁇ m, the heat fusibility of the resulting encapsulated toner is undesirably poor.
  • thermally dissociating encapsulated toners which is preferably used in the present invention will be described below, but the present invention is not restricted to these alone.
  • the method of forming fixed images of the present invention comprises preheating a recording medium, and thereafter simultaneously transferring and fixing the visible image onto the preheated recording medium.
  • the recording system used for the method of forming fixed images of the present invention is not limitative to a particular one, and as long as the transferring and fixing to the recording medium can be carried out, any system can be applied.
  • the method of forming fixed images can be applicable to systems using an electrographic process and electrostatic recording process.
  • the present invention can be applicable to systems using other processes such as a magnetographic process and an ion deposition process.
  • FIG. 1 is a schematic view of an apparatus used in the method ⁇ f forming fixed images as defined by the present invention showing one example using the electrographic process.
  • Element 1 is a photoconductor such as of amorphous silicon or organic photoconductor, etc. in which a photoconductive layer is provided on a conductive supporter.
  • photoconductors those practically used are photoconductors of selenium, silicon, organic groups, etc., and any of these can be used.
  • the silicon photoconductors and the organic photoconductors having good heat resistance are preferred.
  • Element 7 is a charger located opposite to the photoconductor 1.
  • the charging means is not particularly restricted, and any of, for instance* a corona charger, a brush charger, a roller charger, etc. can be used.
  • Element 2 is an exposure device located opposite to the photoconductor 1 for forming electrostatic latent images on the photoconductor surface.
  • light sources such as laser beams, LED or EL arrays, etc. are used in combination with an image-forming optical system.
  • a device based on optical systems projecting a reflected light of a document generally provided in the copying machine can be used.
  • Element 3 is a developer device located opposite to the photoconductor 1 for making visible the electrostatic latent image formed on the photoconductor with the toner.
  • a developer device any of the commonly used two-component magnetic brush developer device, the one-component magnetic brush developer device, the one-component non-magnetic developer device, etc. can be used.
  • Element 4 is a heater, and element 5a is a pressure roller, and the heater 4 is disposed just before the point where the photoconductor 1 contacts the pressure roller 5a, so that the preheated recording medium can be conveyed to the pressure roller.
  • the heater 4 is preferably set at a proper distance from the photoconductor so as not to cause thermal effects or thermal deformation on the photoconductor.
  • the heater 4 is a device for preheating the surface of the recording medium such as a recording paper, wherein the surface comes in contact with the toner.
  • any type of heat source can be used for the heater 4.
  • Heating bodies of the heater 4 include, ' for example, a hot plate, a quartz heater, a flash heater, a heating belt, a heating element, etc., with preference given to the quartz heater and the heating element.
  • the pressure roller 5a is a means for pressure-welding the preheated recording medium onto the surface of the photoconductor. In an ordinary fixing device, it is necessary to use heat-resistant silicone rubbers, etc. to carry out fixing at a high temperature.
  • the pressure roller having a particularly high heat resistance since the pressure roller in contact with the reverse side of the preheated recording medium is not directly heated, and the temperature transmitted to the pressure roller is remarkably low. Therefore, as long as the materials for the pressure roller are elastic bodies having a good heat resistance at not less than 150°C , there are no limitations, and any of the ordinary inexpensive elastic materials including, for instance, heat-resistant polyurethane resins, acrylic resins, nitrile resins and non-conjugated diene terpolymer resins such as EPDM can be used.
  • the nip pressure of the pressure roller is usually 0.1 to 4.0 kg/cm, preferably 0.2 to 2 kg/cm, the durability thereof becomes longer.
  • a belt may be used as a similar means in the place of the pressure roller.
  • the cleaner device 8 such as a cleaning web for removing trace amounts of the toner remaining on the surface of the photoconductor is arranged opposite to the photoconductor 1.
  • the photoconductor 1 and the pressure roller 5a rotate at a constant peripheral speed in the direction shown in Figure 1 by a specified driving means not illustrated in the figure.
  • a recording paper 6 used as a recording medium is conveyed in the manner shown in Figure 1.
  • the recording paper 6 is then pressed between the pressure roller 5a and the photoconductor 1 to transfer and fix the visible image, and discharged out of the system by a paper discharging means not illustrated in the figure.
  • the conveying speed of the recording medium and the heating temperature of the heater is so regulated that the preheating temperature for the recording medium is maintained within the predetermined temperature ranges.
  • Element 21 is a voltage-applying device, element 23 a developer, element 27 an insulating endless film belt, element 29 a toner, element 24 a heater and element 25 a pressure roller.
  • the voltage-applying device 21 is arranged opposite to the surface of the insulating endless film belt 27. It serves as a means for applying pulse voltage to a plurality of pin electrodes while driving the insulating endless film belt 27 along with the pin electrodes to carry out discharging on the insulating endless film belt, so that charges expressed by a character or a symbol are supplied onto the insulating endless film belt.
  • the toner 29 in the developer 23 is applied to the obtained electrostatic latent image.
  • the insulating film belt 27 having a thickness of 5 ⁇ m to 20 ⁇ m and made of heat-resistant films such as polyester resins, polyimide resins, polyamide resins, and other non- heat resistant films such as polypropylene films, polyethylene films, cellophane, etc. or conductive layers provided with dielectric coating can be used.
  • the insulating endless film belt 27 is stretched with holding rollers 30.
  • the heater 24 is disposed just before the point where the insulating endless film belt 27 contacts the pressure roller 25, so that the preheated recording medium 26 can be conveyed to the pressure roller 25.
  • the heater 24 is a device for preheating the surface of the recording medium such as a recording paper, wherein the surface comes in contact with the toner. As long as it is a device capable of heating the surface of the recording medium up to 160 ⁇ C , any type of heat source can be used for the heater 24. The same devices as in the case of electrophotographic process can be used.
  • the pressure roller 25 is a means for pressure-welding the preheated recording medium onto the surface of the insulating endless film belt 27.
  • the pressure roller having a particularly high heat resistance since preheated heat is not directly transmitted to the pressure roller. Therefore, as long as the materials for the pressure roller are elastic bodies having a good heat resistance at not less than 150 ⁇ C , there are no limitations on its materials, and any of the ordinary inexpensive elastic materials which can be used for the electrophotographic process can be also used.
  • the nip pressure of the pressure roller is usually 0.1 to 4.0 kg/cm, preferably 0.2 to 2 kg/cm, the durability thereof becomes longer.
  • a belt may be used as a similar means in the place of the pressure roller. The conveying speed of the recording medium and the heating temperature of the heater is so regulated, as in the case of the electrophotographic process, that the preheating temperature for the recording medium is maintained within the predetermined temperature range.
  • a cleaning web 28 is arranged opposite to the insulating endless film belt 27 not only to remove trace amounts of the residual toner but also to cool the insulating endless film belt 27 after transferring and fixing to the recording paper. Further, a charge remover 22 such as a conductive brush and a conductive roll removes the residual charges, and thereby the insulating endless film belt 27 is recovered to its initial state for reuse.
  • a charge remover 22 such as a conductive brush and a conductive roll removes the residual charges, and thereby the insulating endless film belt 27 is recovered to its initial state for reuse.
  • the toner used in the method of the present invention is not subject to charging in the transfer process, not only insulating encapsulated toners but also conductive encapsulated toners can be used.
  • insulating encapsulated toners but also conductive encapsulated toners can be used.
  • encapsulated toners are conceivable, and as long as they are within the range of the required thermal properties, there are no limitations on what production process or materials are used.
  • those having thermal properties capable of melting the toner on the recording medium heated in advance at a temperature range of between 50 ⁇ C and 160 ⁇ C and of fixing the toner by pressure of a pressure roller can be properly chosen.
  • the fixing temperature of the toner to the recording medium is in the range of between 40 ⁇ C and 120°C .
  • Figure 4 shows a charging process, Figure 5 an exposing process, Figure 6 a developing process and Figure 7 a transfer and fixing process.
  • a specified charge is uniformly supplied, e.g. by the corona charger 7 to the photoconductor surface.
  • a photoconductor sensitive to a positive charge is taken here for an example, and the surface of the conductive supporter 1b is coated with the photoconductive layer 1a to form the photoconductor 1.
  • a high voltage is applied by the corona charger 7 to the photoconductive layer 1a, thereby positively charging the surface of the photoconductive layer 1a.
  • a light from the exposure device 2 is irradiated to the surface of the related photoconductor, so that a leakage of charges occurs only in the exposed parts to form an electrostatic latent image on the photoconductive layer 1a.
  • the toner triboelectrically charged inside the developer device is transported by the rotating sleeve 3a, and developed onto the photoconductor surface in proportion to the charge on the photoconductor surface.
  • the developing process is an assortment of normal development in which a reversely polarized toner adheres to the charges by the Coulomb's force and of reverse development in which the toner adheres to the charges lost due to exposure to the light.
  • the development process in the present invention applies to either method, but the case of the normal development is illustrated in Figure 6.
  • the visible image formed by applying the toner to adhere to a latent image on the surface of the photoconductor is conveyed.
  • a recording medium 6 such as a recording paper preheated by a heater 4 is pressure-welded onto the surface of the photoconductor by pressing the reverse side of the recording medium by a pressure roller 5a so as to synchronize with the initial end of the visible image, and thereby the visible image is simultaneously transferred and fixed onto the recording medium 6.
  • the surface of the recording medium is usually heated to a temperature of between 50 ⁇ C and 160 ⁇ C , preferably between 50°C and 120 ⁇ C .
  • a toner collecting device is not required.
  • trace amounts of the toner may remain on the surface of the photoconductor 1 after the transferring of the toner to the recording medium 6, this toner can be removed by pressure- welding the photoconductor with such devices as a cleaning web arranged opposite to the photoconductor, making it possible to repeatedly use the photoconductor.
  • the charges remaining on the photoconductor are neutralized by a charge eraser 9 such as a charge erasing lamp arranged opposite to the photoconductor 1 , so that the photoconductor 1 is reused for the charging process.
  • the electrostatic recording process at first, charges represented by characters or symbols are supplied on the insulating endless film belt 27 by a voltage-applying device 21 as shown in Figure 2 to form an electrostatic latent image thereon.
  • the resulting latent image is formed into a visible image by adhering the toner 29 in the developer.
  • the transfer and fixing process is carried out in the same manner as in the case of the electrophotographic process by passing a recording medium 26, heated in advance by a heater 24, between a pressure roller 25 and the insulating endless film belt 27.
  • the insulating endless film belt rotates in a direction shown in the figure at a constant peripheral speed by a specified driving means not illustrated in the figure to convey the visible image formed by applying the toner to the surface of the insulating endless film belt.
  • the reverse side of the recording medium 26 is pressed by a pressure roller 25 to pressure weld the preheated recording medium 26 onto the surface of the insulating endless film belt 27 so as to synchronize with the initial end of the visible image. Therefore, the transferring of the toner to the recording medium 26 takes place at the same time of the fixing of the visible images.
  • the recording medium is heated to a temperature range similiar to that described for the case of the electrophotographic process.
  • the recording paper is discharged from the system by a discharging means.
  • the present invention is not confined to the above-mentioned embodiments, and specifications of the kinds of individual apparatus, processes etc. can be revised based on the principles of the present invention.
  • the temperature of the heating body in the fixing device can be set low with only a small rise in the temperature in the system, thereby making it possible to miniaturize the forced radiation device.
  • a cardboard paper is also applicable for the method of the present invention.
  • the conductive toners can also be used, and an electrostatic inducing-type development capable of applying low voltage can also be used.
  • the present invention is hereinafter described in more detail by means of the following working examples, but the present invention is not limited by them.
  • the obtained mixture is introduced into an attritor (manufactured by Mitsui Miike Kakoki) and dispersed at 10°c for 5 hours to give a polymerizable composition.
  • This composition is added to 800 g of a 4% by weight aqueous colloidal solution of tricalcium phosphate which has been preliminarily prepared in a 2-liter separable glass flask, so as to give a concentration of 30% by weight.
  • the obtained mixture is emulsified and dispersed with a TK homomixer (manufactured by Tokushu Kika Kogyo) at 5°C and a rotational speed of 10000 rpm for 2 minutes.
  • a four-necked glass cap is set on the flask, and a reflux condenser, a thermometer, a dropping funnel fitted with a nitrogen inlet tube and a stainless steel stirring rod are set thereon.
  • the resulting flask is placed on an electric mantle heater.
  • a solution of 22.0 g of resorcinol, 3.6 g of diethyl malonate and 0.5 g of 1 ,4-diazabicyclo [2.2.2] octane in 40 g of ion-exchanged water is prepared, and the resulting mixture is dropped into the flask in a period of 30 minutes through the dropping funnel while stirring. Thereafter, the contents are heated to 80 ⁇ C and reacted for 10 hours in a - 37 -
  • polyester resin Bisphenol- type polyester resin; softening point: 135°C ; Tg: 65°C
  • carbon black manufactured by Mitsubishi Kasei Ltd., MA8
  • charge control agent Hodogaya Kagaku Ltd., Aizenspilon Black TRH
  • the obtained mixture After cooling the obtained mixture, it is pulverized with a pulverizing mill and then classified with a classifier to obtain a toner having a particle distribution range of 5 to 25 ⁇ m and an average particle size of 10 # m.
  • a colloidal silica Nahon Aerozil Ltd.: R972
  • Test Example 1 50 g of the toner obtained in Production Example of Encapsulated Toner is blended together with 1 kg of a commercially available ferrite carrier by using a V-type blender to obtain a developer 1.
  • the obtained developer 1 is used to carry out copying by using a modified apparatus of a commercially available copying machine as schematically shown in Figure 1.
  • a quartz heater is used as a heater and arranged at a distance of 5 cm away from the point where the photoconductor contacts the pressure roller.
  • the temperature on the surface of the recording paper is properly adjusted so as to preheat the paper surface to a temperature of between 60°C and 160°C •
  • the pressure roller used in the transfer and fixing is made of silicone rubber having a roller diameter of 30 mm , and transfer and fixing are carried out at a nip pressure of 0.5 kg/cm and a peripheral speed of 160 mm/sec.
  • the lowest fixing temperature of the paper surface is 90°C , and substantially no melting of the toner to the surface of the photoconductor is observed at a temperature of between 80°C and 160°C .
  • the toner obtained by the Production Example of Reference Toner is blended with a commercially available ferrite carrier to prepare a developer 2. Copying is carried out in the same manner as above using the modified apparatus. As a result, the lowest fixing temperature of the paper surface is 140°C .
  • the lowest fixing temperature for the toner is the - 39 -
  • This fixing rate of the toner is determined by placing a load of 500 g on a sand-containing rubber eraser having a bottom area of 15 mm x 7.5 mm which contacts the fixed toner image, placing the loaded eraser on a fixed toner image obtained in the fixing device, moving the loaded eraser on the image backward and forward five times, measuring the optical reflective density of the eraser-treated image with a reflective densitometer manufacturecd by Macbeth Co., and then calculating the fixing rate from this density value and a density value before the eraser treatment using the following equation.
  • the developer 1 obtained in Test Example 1 is used to carry out copying by using a modified apparatus of a commercially available copying machine as schematically shown in Figure 2.
  • a quartz heater is used as a heater and arranged at a distance of 5 cm away from the point where the insulating endless film belt contacts the pressure roller.
  • the temperature on the paper surface of the recording paper is properly adjusted so as to preheat the paper surface to a temperature of between 60°C and 130°C •
  • the pressure roller used in the transfer and fixing is made of EPDM having a roller diameter of 30 mm ⁇ , and transfer and fixing are carried out at a nip pressure of 0.5 kg/cm and a peripheral speed of 160 mm/sec.
  • the lowest fixing temperature of the paper surface is 95°C , and substantially no melting of the toner to the surface of the insulating endless film belt is observed at a temperature of between 80°C and 130°C •
  • the toner obtained by the Production Example of Reference Toner is blended with a commercially available ferrite carrier to prepare a developer 2. Copying is carried out in the same manner as above using the modified apparatus. As a result, the fixing rate at the highest fixing temperature of 130°c is 60%.

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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)
  • Fixing For Electrophotography (AREA)

Abstract

Procédé de formation d'images fixes consistant à former une image électrostatique latente, à développer cette image électrostatique latente puis à appliquer un toner sur cette image afin d'obtenir une image visible et à transferer et fixer simultanément l'image visible ainsi réalisée sur un support préchauffé.
PCT/JP1992/000668 1991-05-30 1992-05-25 Procede de formation d'images fixes WO1992022017A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP15529691A JPH04353885A (ja) 1991-05-30 1991-05-30 画像形成方法
JP3/155296 1991-05-30
JP3155297A JPH04353863A (ja) 1991-05-30 1991-05-30 画像形成方法
JP3/155297 1991-05-30

Publications (1)

Publication Number Publication Date
WO1992022017A1 true WO1992022017A1 (fr) 1992-12-10

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP1992/000668 WO1992022017A1 (fr) 1991-05-30 1992-05-25 Procede de formation d'images fixes

Country Status (2)

Country Link
EP (1) EP0586699A1 (fr)
WO (1) WO1992022017A1 (fr)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3133021A1 (de) * 1980-08-25 1982-04-15 Konishiroku Photo Industry Co., Ltd., Tokyo Bildwiedergabegeraet
GB2107892A (en) * 1981-10-16 1983-05-05 Fuji Photo Film Co Ltd Encapsulated electrostatographic toner

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3133021A1 (de) * 1980-08-25 1982-04-15 Konishiroku Photo Industry Co., Ltd., Tokyo Bildwiedergabegeraet
GB2107892A (en) * 1981-10-16 1983-05-05 Fuji Photo Film Co Ltd Encapsulated electrostatographic toner

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 14, no. 422 (P-1104)(4365) 12 September 1990 & JP,A,2 163 749 ( CANON ) 25 June 1990 *
PATENT ABSTRACTS OF JAPAN vol. 7, no. 10 (P-168)(1155) 14 January 1983 & JP,A,57 168 267 ( RICOH ) 16 October 1982 *
PATENT ABSTRACTS OF JAPAN vol. 8, no. 6 (P-247)(1443) 12 January 1984 & JP,A,58 168 071 ( CANON ) 4 October 1983 *
PATENT ABSTRACTS OF JAPAN vol. 9, no. 86 (P-349)(1809) 16 April 1985 & JP,A,59 214 862 ( TOSHIBA ) 4 December 1984 *

Also Published As

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EP0586699A1 (fr) 1994-03-16

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