EP1424606A2 - Révélateur électrophotographique à chargement positive et procédé pour sa fabrication - Google Patents

Révélateur électrophotographique à chargement positive et procédé pour sa fabrication Download PDF

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Publication number
EP1424606A2
EP1424606A2 EP03026952A EP03026952A EP1424606A2 EP 1424606 A2 EP1424606 A2 EP 1424606A2 EP 03026952 A EP03026952 A EP 03026952A EP 03026952 A EP03026952 A EP 03026952A EP 1424606 A2 EP1424606 A2 EP 1424606A2
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EP
European Patent Office
Prior art keywords
toner
resin
parts
control agent
charge control
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP03026952A
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German (de)
English (en)
Other versions
EP1424606A3 (fr
Inventor
Manabu Sawada
Kei Yamaguchi
Shinichiro Nishimaki
Hiroshi Emori
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Fuji Electric Imaging Device Co Ltd
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Fuji Electric Imaging Device Co Ltd
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Publication date
Application filed by Fuji Electric Imaging Device Co Ltd filed Critical Fuji Electric Imaging Device Co Ltd
Publication of EP1424606A2 publication Critical patent/EP1424606A2/fr
Publication of EP1424606A3 publication Critical patent/EP1424606A3/fr
Withdrawn legal-status Critical Current

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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
    • G03G9/087—Binders for toner particles
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • 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
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2913—Rod, strand, filament or fiber
    • Y10T428/2933—Coated or with bond, impregnation or core
    • Y10T428/294—Coated or with bond, impregnation or core including metal or compound thereof [excluding glass, ceramic and asbestos]
    • Y10T428/2956—Glass or silicic fiber or filament with metal coating
    • 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
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
    • Y10T428/2984—Microcapsule with fluid core [includes liposome]
    • Y10T428/2985—Solid-walled microcapsule from synthetic polymer
    • 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
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
    • Y10T428/2991—Coated
    • Y10T428/2993—Silicic or refractory material containing [e.g., tungsten oxide, glass, cement, etc.]

Definitions

  • the present invention relates to an electrostatic latent image toner that can be used in an electrophotographic type image forming apparatus, and in particular to an electrophotographic positively charged toner, and a manufacturing method thereof.
  • the toner is conveyed and attached to an electrostatic latent image on the surface of a photoreceptor that has been formed through previous charging and exposure steps, whereby the image is made visible.
  • the toner image is transferred from the surface of the photoreceptor onto a transfer medium (paper etc.) in a subsequent transfer step, and is then fused in a fusing step, before the transfer medium (paper etc.) is discharged in a state having the image printed thereon as a printed image.
  • the developing step can be broadly classified into a two-component developing method in which a toner and a carrier are used in combination, and a one-component developing method in which a toner is used alone.
  • the toners used in these developing methods are generally obtained by dispersing carbon black, a pigment or the like as a colorant through hot melt-kneading in a binder resin comprising a thermoplastic resin such as a natural resin, and then carrying out dry pulverization into fine particles.
  • the colorant may be dispersed by kneading in a binder resin having a styrene-acrylic copolymer as a principal component thereof using an agitator such as a Kneader, an Extruder or a Banbury mixer, and then fine pulverization into particles of size approximately 5 to 20 ⁇ m may be carried out to obtain the toner.
  • a magnetic toner can be obtained by further including a magnetic powder such as magnetite when carrying out the kneading and dispersion.
  • Toners used in the above-mentioned developing methods must in all cases be given a charge of positive or negative polarity corresponding to the polarity of the positive or negative charge on the surface of the photoreceptor before the formation of the electrostatic latent image, and this charge must be maintained.
  • the charge bestowing ability for this purpose it is possible to use the tribo-charging ability inherent to a material such as a binder resin or a colorant that is a constituent component of the toner, but in general the charge amount obtained through the tribo-charging ability inherent to such a material is often too low for good image formation, and hence an image developed using only this tribo-charging is prone to being indistinct, with background fog being observed and so on.
  • a substance called a charge control agent such as a dye, a pigment or a specially synthesized organic compound, that makes it easy to bestow chargeability is specially added.
  • charge control agents there are materials for charge bestowing ability of each of positive and negative polarity, with various materials being known for each.
  • colorants such as various azine compounds, nigrosine dyes, triphenylmethane dyes and phthalocyanine pigments, and also quaternary ammonium salt compounds, and resins containing a quaternary ammonium salt group or an amine group, and so on are well known materials, and these have been widely used from hitherto.
  • Such charge control agents are usually used singly.
  • the nigrosine dye type positive charge control agents have often been used alone from hitherto, but because the chemical structure is complex, and chemical stability as a substance is poor, there has been a problem that chemical decomposition or degeneration is easily brought about through heat and mechanical shock due to friction during hot melt-kneading and so on, and hence the charge stability is impaired and thus the charging ability drops, and hence the original charge bestowing ability can no longer be exhibited.
  • the tribo-charging polarity of the resin itself in the developing step is generally negative, and hence in the case of adjusting a toner to be positively charged overall through the action of an added positive charge control agent, the positive charge bestowing ability possessed by the toner may not necessarily be sufficient and stable compared with the negative charge bestowing ability.
  • an electrophotographic positively charged toner comprising a core toner that has a binder resin, a wax, a colorant and a charge control agent as principal component materials thereof and has been spherified through heat treatment, and at least fine silica particles as an external additive, wherein the charge control agent contains a resin having a quaternary ammonium salt group as a functional group and a nigrosine dye.
  • the electrophotographic positively charged toner of claim 1 is preferably made to be such that the charge control agent contains 2 to 10 parts by weight of the resin having a quaternary ammonium salt group as a functional group, and 0.5 to 5 parts by weight of the nigrosine dye, per 100 parts by weight of the binder resin.
  • the electrophotographic positively charged toner of claim 1 or 2 is preferably made to be such that the resin having a quaternary ammonium salt group as a functional group has as a principal component thereof a styrene-acrylic copolymer resin containing a repeat unit represented by undermentioned formula (1) and a repeat unit represented by undermentioned formula (2) (where, in the formulae, R 1 and R 2 represent a hydrogen atom or a methyl group, R 3 represents an alkylene group, and R 4 , R 5 and R 6 each represents an alkyl group, and the styrene-acrylic copolymer resin comprises 65 to 97 wt% of the repeat unit represented by undermentioned formula (1) and 35 to 3 wt% of the repeat unit represented by undermentioned formula (2), and has a weight average molecular weight in a range of 2,000 to 10,000)
  • the electrophotographic positively charged toner of any one of claims 1 through 3 is preferably made to be such that the binder resin has a styrene-acrylic copolymer resin as a principal component thereof.
  • the electrophotographic positively charging toner of any one of claims 1 through 4 is preferably made to contain 3 to 6 parts by weight of carbon black exhibiting a pH of at least 8.0 as the colorant per 100 parts by weight of the binder resin.
  • the above object is attained through a method of manufacturing the electrophotographic positively charging toner of any one of claims 1 through 5, comprising mixing/agitating the binder resin, the wax, the colorant and the charge control agent as principal component materials, then hot melt-kneading, pulverizing and classifying the kneaded material obtained to produce a core toner, spherifying the core toner through hot air blast treatment, and then mixing in at least silica fine particles as an external additive.
  • the charge control agent is made to contain a resin having a quaternary ammonium salt group as a functional group and a nigrosine dye; as a result, an electrophotographic positively charged toner and a manufacturing method thereof can be provided, according to which even if after kneading, pulverization and classification the toner is spherified by melting the surfaces of the particles in a hot air current, the charge control agent is not coated and hence the charging ability thereof is not reduced, and thus the toner has sufficient tribo-charging ability for good image formation, excellent transfer efficiency, and excellent charge build-up performance and excellent charge stability upon continuous printing.
  • the electrophotographic positively charged toner of the present invention is obtained by taking a binder resin, a wax, a colorant and a charge control agent as principal component materials, mixing/agitating these materials, then hot melt-kneading, pulverizing and classifying the kneaded material obtained, spherifying the core toner thus obtained, and then mixing in an external additive of silica fine particles and so on to further improve the fluidity of the toner.
  • a binder resin, a wax, a colorant and a charge control agent as principal component materials, mixing/agitating these materials, then hot melt-kneading, pulverizing and classifying the kneaded material obtained, spherifying the core toner thus obtained, and then mixing in an external additive of silica fine particles and so on to further improve the fluidity of the toner.
  • a resin having as a principal component thereof an ordinary thermoplastic resin having good fusing ability well known as a binder resin from hitherto can be used.
  • the charge control agent according to the present invention has a styrene-acrylic copolymer resin as a base thereof, a styrene-acrylic copolymer resin is preferable as the binder resin, since then compatibility is excellent, and hence there is an effect of separating away of the charge control agent upon repeated use of the toner being prevented.
  • the resin in the case of using a styrene-acrylic copolymer resin as the binder resin, for example, to obtain both good fusing ability and good offset resistance for the toner, it is preferable for the resin to exhibit a molecular weight distribution in a range of 2,000 to 900,000, with peaks at both a low molecular weight of several thousand and a high molecular weight of several hundred thousand.
  • the electrophotographic positively charged toner of the present invention contains a wax for the purpose of improving the offset resistance.
  • a wax for the purpose of improving the offset resistance.
  • a publicly known wax such as polyethylene wax, polypropylene wax, beeswax or carnauba wax can be used.
  • the amount added of the wax is preferably in a range of 1 to 7 parts by weight per 100 parts by weight of the binder resin. At less than 1 part by weight, the offset resistance will become poor, and at more than 7 parts by weight, the toner particles will become prone to coagulating together.
  • the colorant contained in the electrophotographic positively charged toner of the present invention a single publicly known dye or pigment such as carbon black, lamp black or iron black, or a mixture thereof can be used.
  • the amount used is preferably in a range of 3 to 6 parts by weight per 100 parts by weight of the binder resin.
  • the carbon black used in the toner according to the present invention is made to be alkaline with a pH of at least 8.0, then the polarity of tribo-charging is positive.
  • the pH of the carbon black is measured using a sludge thereof.
  • the pH is affected primarily by the number of oxygen-containing groups on the surface of the carbon black and the amount of ash (metal oxides and other residues). It is known that in general channel black is acidic, and furnace black is neutral to alkaline.
  • a resin having a quaternary ammonium salt group as a functional group and a nigrosine dye are used together as the charge control agent contained in the electrophotographic positively charged toner of the present invention.
  • a positive charge control agent as described in detail in Japanese Patent Application Laid-open No. S63-60458 can be used.
  • the weight average molecular weight Mw of this resin (copolymer) is 2,000 to 10,000. If the weight average molecular weight Mw is less than 2,000, then the drop in the charge amount under a high-temperature high-humidity environment will be large, and offset will become prone to occurring during fusing.
  • the weight average molecular weight Mw is more than 10,000, then the compatibility with the binder resin will be poor, and hence uniform dispersion will become difficult to obtain.
  • a weight average molecular weight Mw of 3,000 to 8,000 is particularly preferable.
  • the viscosity of the above resin effects the ability to be kneaded with the binder resin and the fusing ability, and hence is preferably 50 to 10,000 poise, particularly preferably 100 to 5,000 poise, at 130°C.
  • the content of the above resin in the toner is preferably 2 to 10 parts by weight per 100 parts by weight of the binder resin.
  • the nigrosine dye is a black dye, and is one well known as a charge control agent from hitherto, and comprises a mixture of a plurality of azine compounds.
  • the content of the nigrosine dye in the toner is preferably 0.5 to 5 parts by weight per 100 parts by weight of the binder resin. At less than 0.5 parts by weight, the charge amount necessary for good image formation will be difficult to obtain, whereas at more than 5 parts by weight, separation away from the toner will become prone to occurring, and hence the charge amount will become unstable.
  • a small amount of a crystalline magnetic material may be added as required with a purpose of increasing the hardness of the toner particles.
  • a fatty acid-modified nigrosine dye, a metal-containing nigrosine dye, a metal-containing fatty acid-modified nigrosine dye, a salicylic acid chromium complex, a quaternary ammonium compound or the like can be used as a charge control agent in the present invention.
  • slip additives such as fine tetrafluoroethylene particles, zinc stearate and titanium oxide, abrasives such as cerium oxide and silicon carbide, fluidity bestowing agents such as hydrophobic silica, electrical conductivity bestowing agents such as carbon black and tin oxide, and so on may be added to the core toner as required.
  • Spherification is carried out on the toner of the present invention to improve the fluidity of the core toner as described earlier, but for good image formation, it is necessary to further improve the fluidity, and hence at least hydrophobic silica is mixed in as an external additive for improving the fluidity.
  • Binder resin Styrene / n-butyl acrylate copolymer resin (CPR250, made by Mitsui Chemicals Inc.) 100 parts (Wax) Low-molecular-weight polypropylene (Hiwax NP-055, made by Mitsui Chemicals Inc.) 5 parts (Colorant) Carbon black (Regal 330R, Cabot Corporation) 6 parts (Charge control agent) Nigrosine dye (Bontron N-01, Orient Chemical Industries, Ltd.) 2 parts Resin having quaternary ammonium salt group as functional group (Acrybase FCA-201-PS, Fujikura Kasei Co., Ltd.) 3 parts (Hiwax, Regal, Bontron and Acrybase are all registered trademarks.)
  • a mixed material of the above composition was thoroughly mixed/agitated in a Henschel mixer, and was then subjected to hot melt-kneading in a twin-screw Extruder; the kneaded material obtained was cooled down to room temperature, and then coarse pulverization, fine pulverization and classification were carried out, thus obtaining an un-spherified black core toner having a mean volumetric particle size of 10 ⁇ m and a particle size distribution of 5 to 20 ⁇ m.
  • An SEM photograph of the un-spherified core toner is shown in Fig. 2. It was found that the un-spherified toner shown in Fig. 2 had very poor fluidity as is. It was thought that this was due to the angular shape of the particles as shown in Fig. 2.
  • FIG. 1 shows a schematic sectional view of the spherifying apparatus for the electrophotographic positively charged toner according to the present invention.
  • Air 102 fed in from a blower 1 is introduced into a hot air blast generator 2, and is made into a hot air blast 103 at 400°C and a flow rate of 0.2 to 0.3 m 3 /min.
  • the hot air blast 103 passes through an introducing pipe 2-1 and is fired into a first cyclone 7 from a hot air blast jetting nozzle 4.
  • the untreated core toner particles 10 are conveyed from a powder fixed amount feeder 3 by a prescribed amount of high-pressure air 101 and are fed into a toner firing device 5, whereupon the untreated core toner particles 10 are jetted into the first cyclone 7 from a firing nozzle 6 by the pressure of the high-pressure air 101.
  • the jetted core toner particles 10 instantaneously contact the hot air blast 103 the temperature of which has been adjusted as mentioned above, and are thus subjected to uniform heat treatment and hence spherified.
  • the core toner particles 10 that have been spherified by the heat treatment are immediately cooled by cooling air 104, pass through an introducing pipe without becoming attached to an inner wall of the first cyclone 7, which is equipped with a cooling water circulating jacket 7-1, and without agglomerating together, and are fed into a second cyclone 8 equipped with a cooling water circulating jacket 8-1, whereupon the spherified toner is further cooled, before being collected in a toner storage vessel 9.
  • the cooling air 105 escapes out from an opening in an upper part of the second cyclone 8 into a bag filter, not shown.
  • An SEM photograph of the spherified toner collected from the spherifying apparatus is shown in Fig. 3. It can be seen from FIG.
  • the charge control agent because a resin having a quaternary ammonium salt group as a functional group and a nigrosine dye are used together as the charge control agent, the problem that has occurred with conventional spherified toners in which the charge control agent is taken into the binder resin, the surface of which has melted through the heat treatment during the spherification, and hence the charge control agent is coated and thus the charge bestowing ability reduction no longer occurs.
  • one component of the charge control agent is a resin
  • this charge control agent resin is attached to and covers the surface of the binder resin that forms the core of the toner before the spherification, and hence even upon the heat treatment during the spherification, the charge control agent resin melts first and coagulates to the binder resin, and thus during this process the charge control agent resin is still at the outermost surface of the toner, and is not coated by the binder resin, and hence the charge bestowing ability works effectively. In fact, long-term stabilization of the charge bestowing ability is obtained through the charge control agent resin being firmly fixed to the binder resin.
  • the charge bestowing ability possessed by the charge control agent resin is considerably lower than that of a nigrosine dye or the like, and hence considering that new problems will thus arise if a large amount of this resin is added alone, it was realized that using a nigrosine dye, which has a high charge bestowing ability, together with the charge control agent resin would result in good effects, whereby the present invention was accomplished.
  • hydrophobic silica NA50Y made by Nippon Aerosil Co., Ltd.
  • the toner according to the present invention thus obtained had a static bulk density of 0.45, and extremely high fluidity was obtained (see Table 1).
  • Examples 2, 3 and 4 were made to be the same as Example 1, except that the contents of the nigrosine dye and the resin having a quaternary ammonium salt group as a functional group in the charge control agent were changed to more desirable combinations of contents within the ranges stipulated in claim 2, specifically 0.6 parts and 2 parts, 3 parts and 5 parts, and 5 parts and 10 parts, per 100 parts of the binder resin.
  • Example 5 was made to be the same as Example 1, except that the content of the resin having a quaternary ammonium salt group as a functional group in the charge control agent was made to be outside the range stipulated in claim 2.
  • Example 6 was made to be the same as Example 1, except that the content of the nigrosine dye in the charge control agent was made to be outside the range stipulated in claim 2.
  • Comparative Example 1 was made to be the same as Example 1, except that the spherification was not carried out.
  • Comparative Example 2 was made to be the same as Example 3, except that the spherification was not carried out.
  • Comparative Example 3 was made to be the same as Example 1, except that the resin having a quaternary ammonium salt group as a functional group was not used in the charge control agent.
  • Comparative Example 4 was made to be the same as Example 1, except that the nigrosine dye was not used in the charge control agent.
  • Nigrosine dye (parts) Charge control agent resin (parts) Spherification Static bulk density Charge amount ( ⁇ C/g) Charge build-up time (s) Initial After 50K sheets Initial After 50K sheets Example 1 2 3 Yes 0.45 55 53 3 3 3 Example 2 0.6 2 Yes 0.44 51 50 4 5 Example 3 3 5 Yes 0.45 53 51 3 4 Example 4 5 10 Yes 0.42 4 8 47 4 3 Example 5 2 12 Yes 0.42 50 48 5 4 Example 6 0.3 5 Yes 0.44 45 43 6 5 Comparative Example 1 2 3 No 0.32 41 35 25 36 Comparative Example 2 3 5 No 0.30 43 31 29 39 Comparative Example 3 2 0 Yes 0.41 35 23 18 26 Comparative Example 4 0 3 Yes 0.44 32 21 19 30 Nigrosine dye (parts) Charge control control agent resin (parts) Solid image density Background fog density Transfer efficiency Evaluation Initial After 50K sheets Initial After 50K sheets Example 1 2 3 1.38 1.39 0.06 0.
  • Binder resin Styrene / n-butyl acrylate copolymer resin (Dianal FB-1157, made by Mitsubishi Rayon Co., Ltd.) 100 parts (Wax) Low-molecular-weight polypropylene (Hiwax NP-055, made by Mitsui Chemicals Inc.) 5 parts (Colorant) Carbon black (Regal 330R, made by Cabot Corporation; pH 8.5) 4 parts (Charge control agent) Nigrosine dye (Bontron N-01, made by Orient Chemical Industries, Ltd.) 1 part Resin having quaternary ammonium salt group as functional group (Acrybase FCA-201-PS, made by Fujikura Kasei Co., Ltd.) 4 parts
  • a mixed material of the above composition was thoroughly mixed/agitated in a Henschel mixer, and was then subjected to hot melt-kneading in a twin-screw Extruder; the kneaded material obtained was cooled down to room temperature, and then coarse pulverization, fine pulverization and classification were carried out, thus obtaining a black core toner having a mean volumetric particle size of 10 ⁇ m and a particle size distribution of 5 to 20 ⁇ m.
  • hydrophobic silica NA50Y made by Nippon Aerosil Co., Ltd.
  • an external additive for bestowing fluidity 100 parts of the core toner obtained as described above in a 20-liter Henschel mixer for 3 minutes at 2000 revs/min, thus carrying out external additive treatment, whereby a toner of the present invention was obtained.
  • 5 parts of this toner of the present invention, and 100 parts of a silicone-resin-coated ferrite carrier having a mean particle size of approximately 60 ⁇ m were mixed together with agitation, thus preparing a two-component developer.
  • the charge amount for this developer was measured using a CF-100 blow-off charge amount measuring device made by Toshiba Chemicals. The result was that the charge amount was 45.5 ⁇ C/g (Table 3). Moreover, the build-up time taken to reach this charge amount was 4 seconds (Table 3).
  • the toner of the present invention obtained through the external additive treatment described above continuous printing of 10,000 sheets was carried out under a high-temperature high-humidity environment of 35°C and 85%RH using a non-magnetic one-component developing type printer equipped with a positively charging organic photoreceptor, and evaluation was carried out. Note that the replenishing toner used in this evaluation test was the same toner of the present invention.
  • Examples 8, 9 and 10 were made to be the same as Example 7, except that the content of the colorant carbon black was changed to 3 parts, 5 parts or 6 parts per 100 parts of the binder resin, which is within the range specified in claim 5 but is different to the content in Example 7.
  • Examples 11, 12 and 13 were made to be the same as Example 7, except that the colorant carbon black was made to be Raven 420 made by Columbia Chemical Company (pH 9), Raven 1020 made by Columbia Chemical Company (pH 8.3) or Black Pearls 880 made by Cabot Corporation (pH 8), all of which exhibit a pH of at least 8.0.
  • Comparative Examples 5, 6 and 7 were made to be the same as Example 7, except that the colorant carbon black was made to be Raven 8000 made by Columbia Chemical Company (pH 2.4), Black Pearls L made by Cabot Corporation (pH 2.5) or Regal 400 made by Cabot Corporation (pH 4), which all exhibit a pH outside the range of the present invention.
  • Comparative Examples 8, 9 and 10 were made to be the same as Example 7, except that the content of the colorant carbon black was made to be 2 parts, 7 parts or 9 parts per 100 parts of the binder resin, which is outside the range specified in claim 5.
  • the printing evaluation is shown in Table 3. From Table 3, it can be seen that, even in the case of evaluation under the severe environmental conditions described above, looking at the row for Example 7, there was little change in the toner properties, i.e. the charge amount and the build-up time thereof, or in the image quality, i.e. the image density of solid parts and the background fog density of non-image parts, between initially and after printing 10,000 sheets, i.e. stable printing quality was obtained.
  • Examples 8 to 10 in which the content of the carbon black was changed as described above and Examples 11 to 13 in which the carbon black was changed to ones of different pH as described above the results were approximately as good as for Example 7.
  • the other evaluation results again it can be seen that there was little change in the toner properties, i.e. the charge amount and the build-up time thereof, or in the image quality, i.e. the image density of solid parts and the background fog density of non-image parts, between initially and after printing 10,000 sheets, i.e. stable printing quality was obtained.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Developing Agents For Electrophotography (AREA)
EP03026952A 2002-11-28 2003-11-25 Révélateur électrophotographique à chargement positive et procédé pour sa fabrication Withdrawn EP1424606A3 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2002345636 2002-11-28
JP2002345636 2002-11-28
JP2003350356A JP2004191934A (ja) 2002-11-28 2003-10-09 電子写真用正荷電トナーおよびその製造方法
JP2003350356 2003-10-09

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EP1424606A2 true EP1424606A2 (fr) 2004-06-02
EP1424606A3 EP1424606A3 (fr) 2005-01-19

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US (1) US20050074608A1 (fr)
EP (1) EP1424606A3 (fr)
JP (1) JP2004191934A (fr)
CN (1) CN1514310A (fr)

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JP2008096969A (ja) * 2006-09-15 2008-04-24 Ricoh Co Ltd トナー、画像形成装置及び画像形成方法
US20090246675A1 (en) * 2008-02-01 2009-10-01 Canon Kabushiki Kaisha Two-component developer, replenishing developer, and image-forming method using the developers
JP5538301B2 (ja) * 2011-05-12 2014-07-02 京セラドキュメントソリューションズ株式会社 正帯電性磁性黒色１成分現像用トナー
CN103608731B (zh) * 2011-06-13 2016-10-12 佳能株式会社 粉末颗粒的热处理设备和调色剂的生产方法
JP6033049B2 (ja) * 2011-12-15 2016-11-30 花王株式会社 静電荷像現像用トナーの製造方法
JP5696126B2 (ja) * 2012-11-15 2015-04-08 京セラドキュメントソリューションズ株式会社 ２成分現像剤
CN103869643B (zh) * 2012-12-13 2016-09-28 周拯 彩色陶瓷碳粉的制备方法
KR20190040465A (ko) * 2017-10-10 2019-04-18 도다 고교 가부시끼가이샤 아닐린 블랙 그리고 해당 아닐린 블랙을 사용한 수지 조성물 및 분산체

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