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EP0945766B1 - Schwarze nicht-magnetische zusammengesetzte Teilchen für schwarze Toner und schwarze Toner, worin sie eingesetzt werden - Google Patents

Schwarze nicht-magnetische zusammengesetzte Teilchen für schwarze Toner und schwarze Toner, worin sie eingesetzt werden Download PDF

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Publication number
EP0945766B1
EP0945766B1 EP19990302317 EP99302317A EP0945766B1 EP 0945766 B1 EP0945766 B1 EP 0945766B1 EP 19990302317 EP19990302317 EP 19990302317 EP 99302317 A EP99302317 A EP 99302317A EP 0945766 B1 EP0945766 B1 EP 0945766B1
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EP
European Patent Office
Prior art keywords
particles
black
hematite
iron oxide
magnetic composite
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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EP19990302317
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English (en)
French (fr)
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EP0945766A3 (de
EP0945766A2 (de
Inventor
Kazuyuki Hayashi
Hiroko Morii
Yasuyuki Tanaka
Seiji Ishitani
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Toda Kogyo Corp
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Toda Kogyo Corp
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Publication of EP0945766A2 publication Critical patent/EP0945766A2/de
Publication of EP0945766A3 publication Critical patent/EP0945766A3/de
Priority to US10/073,362 priority Critical patent/US20020182525A1/en
Application granted granted Critical
Publication of EP0945766B1 publication Critical patent/EP0945766B1/de
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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/083—Magnetic toner particles
    • G03G9/0838—Size of magnetic components
    • 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
    • G03G9/083—Magnetic toner particles
    • G03G9/0839—Treatment of the magnetic components; Combination of the magnetic components with non-magnetic materials
    • 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
    • G03G9/0902—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
    • G03G9/09—Colouring agents for toner particles
    • G03G9/0902—Inorganic compounds
    • G03G9/0904—Carbon black

Definitions

  • the present invention relates to black non-magnetic composite particles for a black toner and a black toner using the black non-magnetic composite particles and to a process to produce them.
  • a black toner prepared by mixing and dispersing non-magnetic black pigments such as carbon black in a binder resin has been widely used as a developer.
  • Recent developing systems have been generally classified into one-component developing methods and two-component developing methods.
  • the black toner and carrier are brought into frictional contact with each other to impart an electrostatic charge having a reverse sign to that of an electrostatic latent image to the black toner, so that the black toner is attached onto the surface of the electrostatic latent image due to an electrostatic attracting force therebetween, thereby neutralizing opposite electrostatic charges on the black toner and the electrostatic latent image.
  • the one-component developing methods since no carrier is used therein, it is not necessary to control a density of the black toner. Besides, a developing apparatus used therefor can be miniaturized due to its simple structure. However, since the one-component developing methods are inferior in developing performance or quality to the two-component developing methods, high techniques have now been required to obtain the same developing performance or quality as those of the two-component developing methods.
  • both types of the black toners are required to exhibit a good insulating property or a high resistance, specifically to have a volume resistivity as high as not less than 10 12 ⁇ cm.
  • the behavior (movement) of a developer in a developing apparatus is strongly governed by the flowability thereof, for example, the flowability of the developer has strong influences on the frictional charging properties between the black toner and the carrier in the case of the two-component developing method, or on the charging property of the black toner on a sleeve in the case of the one-component developing method.
  • the enhancement in image quality such as image density, or tone gradation or in developing speed in the developing apparatus, it has been strongly demanded to increase the flowability of the black toner.
  • toners having a small particle size it has been reported that by using toners having a particle size of 8.5 to 11 ⁇ m, fogs on a background area as well as toner consumption can be reduced. Further, it has been proposed that by using polyester-based toners having a particle size of 6 to 10 ⁇ m, an image quality, a charging stability and lifetime of the developer can be improved. However, when such toners having a small particle size are used, it has been required to solve many problems, e.g., those problems concerning productivity, sharpness of particle size distribution, improvement in flowability, etc.”.
  • the black toner As described above, it has been strongly demanded to enhance various properties of the black toner. It is known that the black toner, especially black pigments exposed to the surface of the black toner, have large influences on developing characteristics. There is a close relationship between properties of the black toner and those of the black pigments mixed and dispersed in the black toner.
  • the flowability of the black toner considerably depends upon the surface condition of the black pigments exposed to the surface of the black toner. Therefore, the black pigments themselves have been strongly required to show an excellent flowability. Further, the blackness and density of the black toner also considerably depend upon the blackness and density of the black pigments contained in the black toner.
  • the black pigments for black toner there may be mainly used carbon black fine particles (Japanese Patent No. 2715336 and Japanese Patent Application Laid-Open (KOKAI) No. 10-39546(1998)).
  • the amount of the carbon black used must be restricted in order to obtain a black toner having a volume resistivity of not less than 10 12 ⁇ cm. For this reason, there arises a problem that a sufficient blackness and a sufficient flowability cannot be obtained.
  • the carbon black fine particles themselves are a conductive material. Therefore, when the carbon black fine particles are used in a large amount in order to enhance the blackness of the black toner, the volume resistivity of the obtained black toner is reduced, so that the toner can be no longer used as a high-resistant or insulated toner. On the contrary, when the amount of the carbon black fine particles used is reduced from the standpoint of a high volume resistivity, the blackness of the black toner is deteriorated.
  • the carbon black fine particles are those particles having an average particle size as fine as 0.010 to 0.060 ⁇ m, the carbon black fine particles are buried within each black toner particle, and the amount of the carbon black fine particles exposed to the surface of each black toner particle is reduced, thereby causing a tendency that the flowability thereof is also deteriorated.
  • the specific gravity of the carbon black fine particles is extremely low, i.e., as low as 1.80 to 1.85, the carbon black fine particles are deteriorated in handling property.
  • the black toner is prepared by dispersing such carbon black fine particles in a binder resin, the bulk specific gravity of the obtained black toner becomes considerably low. Therefore, the obtained toner tends to be scattered around, and deteriorated in flowability.
  • black non-magnetic composite particles for a black toner composition comprising:
  • the black non-magnetic composite particles according to the present invention comprise hematite particles or iron oxide hydroxide particles as core particles having an average paricle diameter of 0.055 to 095 ⁇ m, a coating comprising an organosilicon compound which is formed on the surface of each hematite particle or iron oxide hydroxide particle, and carbon black adhered on the coating comprising the organosilicon compound.
  • the core particles in the present invention there may be exemplified hematite particles, iron oxide hydroxide particles or mixed particles thereof.
  • black hematite particles, black iron oxide hydroxide particles or mixed particles thereof are preferred.
  • the iron oxide hydroxide particles there may be exemplified goethite particles, lepidicrosite particles.
  • the black hematite particles there may be exemplified manganese-containing hematite particles which contain manganese in an amount of 5 to 40 % by weight, preferably 10 to 20 % by weight (calculated as Mn) based on the weight of the manganese-containing hematite particles.
  • the black iron oxide hydroxide particles there may be exemplified manganese-containing iron oxide hydroxide particles such as manganese-containing goethite particles, which contain manganese in an amount of 5 to 40 % by weight, preferably 10 to 20 % by weight (calculated as Mn) based on the weight of the manganese-containing iron oxide hydroxide particles.
  • the core particles from the standpoint of the particle shape thereof, there may be used any isotropic particles such as spherical particles, granular particles or polyhedral particles, e.g., hexahedral particles or octahedral particles, or any anisotropic particles having an aspect ratio (average major axial diameter/average minor axial diameter, hereinafter referred to merely as "aspect ratio") of not less than 2.0:1, such as acicular particles, spindle-shaped particles or rice grain-shaped particles.
  • the isotropic particles are preferably used as the core particles. Among these isotropic particles, the spherical particles and the granular particles are more preferred.
  • the average particle size (diameter) thereof is 0.055 to 0.95 ⁇ m, preferably 0.065 to 0.75 ⁇ m, more preferably 0.065 to 0.45 ⁇ m.
  • the ratio of an average particle length to an average particle breadth thereof is usually not less than 1.0:1 and less than 2.0:1, preferably 1.0:1 to 1.8:1, more preferably 1.0:1 to 1.5:1.
  • the average major axial diameter thereof is 0.055 to 0.95 ⁇ m, preferably 0.065 to 0.75 ⁇ m, more preferably 0.065 to 0.45 ⁇ m.
  • the aspect ratio (average major axial diameter/average minor axial diameter) thereof is 2.0:1 to 20.0:1, preferably 2.0:1 to 15.o:1, more preferably 2.0:1 to 10.0:1.
  • the average particle diameter of the hematite particles or iron oxide hydroxide particles is more than 0.95 ⁇ m, the obtained black non-magnetic composite particles are coarse particles and are deteriorated in tinting strength.
  • the average particle diameter is less than 0.055 ⁇ m, the intermolecular force between the particles is increased due to the reduction in particle diameter, so that agglomeration of the particles tends to be caused. As a result, it becomes difficult to uniformly coat the surface of the hematite particles or iron oxide hydroxide particle with the organosilicon compounds, and uniformly adhere the carbon black fine particles on the surface of the coating comprising the organosilicon compounds.
  • the particles tend to be entangled with each other, and it also becomes difficult to uniformly coat the surfaces of the hematite particles or iron oxide hydroxide particles with the organosilicon compounds, and uniformly adhere the carbon black fine particles on the surface of the coating composed of the organosilicon compounds.
  • the geometrical standard deviation value thereof is preferably not more than 2.0, more preferably not more than 1.8, still more preferably not more than 1.6.
  • the geometrical standard deviation value thereof is more than 2.0, coarse particles are contained therein, so that the particles are inhibited from being uniformly dispersed. As a result, it also becomes difficult to uniformly coat the surfaces of the hematite particles or iron oxide hydroxide particles with the organosilicon compounds, and uniformly adhere the carbon black fine particles on the surface of the coating composed of the organosilicon compounds.
  • the lower limit of the geometrical standard deviation value is 1.01. It is industrially difficult to obtain particles having a geometrical standard deviation value of less than 1.01.
  • the BET specific surface area of the hematite particles or iron oxide hydroxide particles thereof is not less than 0.5 m 2 /g.
  • the BET specific surface area is less than 0.5 m 2 /g, the hematite particles or iron oxide hydroxide particles may become coarse particles, or the sintering between the particles may be caused, so that the obtained black non-magnetic composite particles also may become coarse particles and tend to be deteriorated in tinting strength.
  • the BET specific surface area of the hematite particles or iron oxide hydroxide particles is preferably not less than 1.0 m 2 /g, more preferably 3.0 m 2 /g.
  • the upper limit of the BET specific surface area of the hematite particles or iron oxide hydroxide particles is usually 70 m 2 /g, preferably 50 m 2 /g, more preferably 20 m 2 /g.
  • the fluidity index thereof is about 25 to about 44.
  • the spherical particles are excellent in fluidity, for example, the fluidity index thereof is about 30 to about 44.
  • the lower limit thereof is usually 18.0 when represented by L* value, and the upper limit thereof is usually 36.0, preferably 34.0 when represented by L* value.
  • the upper limit thereof is usually 38.0, preferably 36.0 when represented by L* value.
  • the lower limit thereof is usually 18.0 when represented by L* value, and the upper limit thereof is usually 28.0, preferably 25.0 when represented by L* value.
  • the lower limit thereof is usually more than 18.0 when represented by L* value, and the upper limit thereof is usually 30.0, preferably 28.0 when represented by L* value.
  • the particle shape and particle diameter of the black non-magnetic composite particles according to the present invention are considerably varied depending upon those of the hematite particles or iron oxide hydroxide particles as core particles.
  • the black non-magnetic composite particles have a similar particle shape to that of the hematite particles or iron oxide hydroxide particles as core particle, and a slightly larger particle size than that of the hematite particles or iron oxide hydroxide particles as core particles.
  • the obtained black non-magnetic composite particles according to the present invention have an average particle diameter of usually 0.06 to 1.0 ⁇ m, preferably 0.07 to 0.8 ⁇ m, more preferably 0.07 to 0.5 ⁇ m and a ratio of an average particle length to an average particle breadth of usually not less than 1.0 and less than 2.0, preferably 1.0 to 1.8, more preferably 1.0 to 1.5.
  • the obtained black non-magnetic composite particles according to the present invention have an average particle diameter of usually 0.06 to 1.0 ⁇ m, preferably 0.07 to 0.8 ⁇ m, more preferably 0.07 to 0.5 ⁇ m, and the aspect ratio of usually 2.0:1 to 20.0:1, preferably 2.0: 1 to 15.0:1, more preferably 2.0:1 to 10.0:1.
  • the obtained black non-magnetic composite particles may be coarse particles, and deteriorated in tinting strength.
  • the average particle diameter thereof is less than 0.06 ⁇ m, the black non-magnetic composite particles tends to be agglomerated by the increase of intermolecular force due to the reduction in particle size, thereby deteriorating the dispersibility in a binder resin upon production of the black toner.
  • the black non-magnetic composite particles may be entangled with each other in the binder resin, so that the dispersibility in binder resin tends to be deteriorated.
  • the geometrical standard deviation value of the black non-magnetic composite particles according to the present invention is preferably not more than 2.0, more preferably 1.01 to 1.8, still more preferably 1.01 to 1.6.
  • the lower limit of the geometrical standard deviation value thereof is preferably 1.01.
  • the geometrical standard deviation value thereof is more than 2.0, the tinting strength of the black non-magnetic composite particles is likely to be deteriorated due to the existence of coarse particles therein. It is industrially difficult to obtain such particles having a geometrical standard deviation of less than 1.01.
  • the BET specific surface area of the black non-magnetic composite particles according to the present invention is usually 1 to 200 m 2 /g, preferably 2 to 150 m 2 /g, more preferably 2.5 to 100 m 2 /g.
  • the BET specific surface area thereof is less than 1 m 2 /g, the obtained black non-magnetic composite particles may be coarse, and the sintering between the particles is caused, thereby deteriorating the tinting strength.
  • the black non-magnetic composite particles tend to be agglomerated together by the increase in intermolecular force due to the reduction in particle diameter, thereby deteriorating the dispersibility in a binder resin upon production of the black toner.
  • the fluidity index thereof is preferably 45 to 80, more preferably 46 to 80, still more preferably 47 to 80.
  • the fluidity index thereof is less than 45, the fluidity of the black non-magnetic composite particles becomes insufficient, thereby failing to improve the fluidity of the finally obtained black toner. Further, in the production process of the black toner, there tend to be caused defects such as clogging of hopper, etc., thereby deteriorating the handling property or workability.
  • the upper limit of the blackness of the black non-magnetic composite particles is usually 20.0, preferably 19.0, more preferably 18.5 when represented by L* value.
  • the upper limit of the blackness of the black non-magnetic composite particles is usually 20.0, preferably 19.5, more preferably 19.0 when represented by L* value.
  • the upper limit of the blackness of the black non-magnetic composite particles is usually 20.0, preferably 18.5, more preferably 18.0 when represented by L* value.
  • the upper limit of the blackness of the black non-magnetic composite particles is usually 20.0, preferably 19.0, more preferably 18.5 when represented by L* value.
  • the L* value thereof is more than 20.0, the lightness of the obtained black non-magnetic composite particles becomes high, so that the black non-magnetic composite particles having a sufficient blackness cannot be obtained.
  • the lower limit of the blackness thereof is 15 when represented by L* value.
  • the dispersibility in binder resin of the black non-magnetic composite particles according to the present invention is preferably 4th or 5th rank, more preferably 5th rank when evaluated by the method described hereinafter.
  • the percentage of desorption of carbon black fine particles from the black non-magnetic composite particles according to the present invention is preferably not more than 20 %, more preferably not more than 10 %.
  • the desorption percentage of the carbon black fine particles is more than 20 %, the desorbed carbon black fine particles tend to inhibit the black non-magnetic composite particles from being uniformly dispersed in the binder resin upon production of the black toner.
  • the coating formed on the surfaces of the core particles comprises at least one organosilicon compound selected from the group consisting of (1) organosilane compounds obtained by drying or heat-treating alkoxysilane compounds; (2) polysiloxanes, or modified polysiloxanes selected from the group consisting of (2-A) polysiloxanes modified with at least one compound selected from the group consisting of polyethers, polyesters and epoxy compounds (hereinafter referred to merely as "modified polysiloxanes”), and (2-B) polysiloxanes whose molecular terminal is modified with at least one group selected from the group consisting of carboxylic acid groups, alcohol groups and a hydroxyl group; and (3) fluoroalkyl organosilane compounds obtained by drying or heat-treating fluoroalkylsilane compounds.
  • organosilicon compound selected from the group consisting of (1) organosilane compounds obtained by drying or heat-treating alkoxysilane compounds
  • the organosilane compounds (1) can be produced by drying or heat-treating alkoxysilane compounds represented by the formula (I): R 1 a SiX 4-a wherein R 1 is C 6 H 5 -, (CH 3 ) 2 CHCH 2 - or n-C b H 2b+1 - (wherein b is an integer of 1 to 18); X is CH 3 O- or C 2 H 5 O-; and a is an integer of 0 to 3.
  • R 1 a SiX 4-a wherein R 1 is C 6 H 5 -, (CH 3 ) 2 CHCH 2 - or n-C b H 2b+1 - (wherein b is an integer of 1 to 18); X is CH 3 O- or C 2 H 5 O-; and a is an integer of 0 to 3.
  • the drying or heat-treatment of the alkoxysilane compounds is conducted, for example, at a temperature of usually 40 to 200°C, preferably 60 to 150°C for usually 10 minutes to 12 hours, preferably 30 minutes to 3 hours.
  • alkoxysilane compounds may include methyl triethoxysilane, dimethyl diethoxysilane, tetraethoxysilane, phenyl triethyoxysilane, diphenyl diethoxysilane, methyl trimethoxysilane, dimethyl dimethoxysilane, tetramethoxysilane, phenyl trimethoxysilane, diphenyl dimethoxysilane, isobutyl trimethoxysilane, decyl trimethoxysilane or the like.
  • methyl triethoxysilane, phenyl triethyoxysilane, methyl trimethoxysilane, dimethyl dimethoxysilane and isobutyl trimethoxysilane are preferred, and methyl triethoxysilane and methyl trimethoxysilane are more preferred.
  • polysiloxanes (2) there may be used those compounds represented by the formula (II): wherein R 2 is H- or CH 3 -, and d is an integer of 15 to 450.
  • polysiloxanes having methyl hydrogen siloxane units are preferred.
  • modified polysiloxanes (2-A) there may be used:
  • the polysiloxanes modified with the polyethers represented by the formula (III) are preferred.
  • terminal-modified polysiloxanes (2-B) there may be used those represented by the formula (VI): wherein R 13 and R 14 are -OH, R 16 OH or R 17 COOH and may be the same or different; R 15 is -CH 3 or -C 6 H 5 ; R 16 and R 17 are -(-CH 2 -) y -; y is an integer of 1 to 15; w is an integer of 1 to 200; and x is an integer of 0 to 100.
  • the polysiloxanes whose terminals are modified with carboxylic acid groups are preferred.
  • the fluoroalkyl organosilane compounds (3) may be produced by drying or heat-treating fluoroalkylsilane compounds represented by the formula (VII): CF 3 (CF 2 ) z CH 2 CH 2 (R 18 ) a' SiX 4-a' wherein R 18 is CH 3 -, C 2 H 5 -, CH 3 O- or C 2 H 5 O-; X is CH 3 O- or C 2 H 5 O-; and z is an integer of 0 to 15; and a' is an integer of 0 to 3.
  • the drying or the heat-treatment of the fluoroalkylsilane compounds may be conducted, for example, at a temperature of usually 40 to 200°C, preferably 60 to 150°C for usually 10 minutes to 12 hours, preferably 30 minutes to 3 hours.
  • fluoroalkylsilane compounds may include trifluoropropyl trimethoxysilane, tridecafluorooctyl trimethoxysilane, heptadecafluorodecyl trimethoxysilane, heptadecafluorodecylmethyl dimethoxysilane, trifluoropropyl triethoxysilane, tridecafluorooctyl triethoxysilane, heptadecafluorodecyl triethoxysilane, heptadecafluorodecylmethyl diethoxysilane or the like.
  • trifluoropropyl trimethoxysilane in view of the desorption percentage and the adhering effect of carbon black fine particles, trifluoropropyl trimethoxysilane, tridecafluorooctyl trimethoxysilane and heptadecafluorodecyl trimethoxysilane are preferred, and trifluoropropyl trimethoxysilane and tridecafluorooctyl trimethoxysilane are more preferred.
  • the coating amount of the organosilicon compounds is usually 0.02 to 5.0 % by weight, preferably 0.03 to 2.0 by weight, more preferably 0.05 to 1.5 % by weight (calculated as Si) based on the weight of the hematite particles or iron oxide hydroxide particles coated with the organosilicon compounds.
  • the coating amount of the organosilicon compounds is less than 0.02 % by weight, it becomes difficult to adhere the carbon black fine particles on the surfaces of the hematite particles or iron oxide hydroxide particles in such an amount enough to improve the fluidity and blackness of the obtained black non-magnetic composite particles.
  • the coating amount of the organosilicon compounds is more than 5.0 % by weight, a sufficient amount of the carbon black fine particles can be adhered on the surfaces of the hematite particles or iron oxide hydroxide particles.
  • the use of such unnecessarily large amount of the organosilicon compounds is meaningless because the effect of enhancing the fluidity and blackness of the obtained black non-magnetic composite particles is already saturated.
  • the carbon black fine particles used in the black non-magnetic composite particles according to the present invention there may be exemplified commercially available carbon black particles such as furnace black, channel black or the like.
  • the commercially available carbon black particles usable in the present invention may include MA100, MA7, #1000, #2400B, #30, MA8, MA11, #50, #52, #45, #2200B, MA600, etc. (tradenames; produced by Mitsubishi Chemical Corp.), Seast9H, Seast7H, Seast6, Seast3H, Seast300, SeastFM, etc. (tradenames; produced by Tokai Carbon Co., Ltd.) or the like.
  • MA100, MA7, #1000, #2400B and #30 are preferred.
  • the average particle size of the carbon black fine particles is usually about 0.002 to about 0.05 ⁇ m, preferably about 0.002 to about 0.035 ⁇ m.
  • the carbon black fine particles are too fine to be well handled.
  • the average particle size of the carbon black fine particles is more than 0.05 ⁇ m
  • the particle size of the carbon black fine particles becomes much larger than that of the hematite particles or iron oxide hydroxide particles as core particles, thereby causing insufficient adhesion of the carbon black fine particles onto the coating composed of the organosilicon compounds, and increasing the desorption percentage of the carbon black fine particles.
  • the obtained black non-magnetic composite particles tend to be deteriorated in dispersibility in a binder resin upon the production of black toner.
  • the ratio of the average particle size of the hematite particles or iron oxide hydroxide particles to that of the carbon black fine particles is preferably not less than 2:1.
  • the ratio is less than 2:1, the particle size of the carbon black fine particles becomes considerably larger as compared to that of the hematite particles or iron oxide hydroxide particles as core particles, thereby causing insufficient adhesion of the carbon black fine particles onto the coat composed of the organosilicon compounds, and increasing the desorption percentage of the carbon black fine particles.
  • the obtained black non-magnetic composite particles tend to be deteriorated in dispersibility in a binder resin upon the production of black toner.
  • the amount of the carbon black fine particles adhered is 1 to 25 parts by weight based on 100 parts by weight of the hematite particles or iron oxide hydroxide particles as core particles.
  • the amount of the carbon black fine particles adhered is less than 1 part by weight, the amount of the carbon black fine particles adhered is insufficient, so that it becomes difficult to obtain black non-magnetic composite particles having a sufficient fluidity and blackness.
  • the obtained black non-magnetic composite particles can show a sufficient fluidity and blackness.
  • the carbon black fine particles tend to be desorbed from the coating composed of the organosilicon compound.
  • the obtained black non-magnetic composite particles tend to be deteriorated in dispersibility in a binder resin upon the production of black toner.
  • the black non-magnetic composite particles according to the present invention at least a part of the surface of the hematite particle or iron oxide hydroxide particle as core particle may be preliminarily coated with at least one compound selected from the group consisting of hydroxides of aluminum, oxides of aluminum, hydroxides of silicon and oxides of silicon (hereinafter referred to as "coat composed of hydroxides and/or oxides of aluminum and/or silicon").
  • the obtained black non-magnetic composite particles can show a higher dispersibility in a binder resin as compared to in the case where the hematite particles or iron oxide hydroxide particles are uncoated with hydroxides and/or oxides of aluminum and/or silicon.
  • the coating amount of the hydroxides and/or oxides of aluminum and/or silicon is preferably 0.01 to 50 % by weight (calculated as Al, SiO 2 or a sum of Al and SiO 2 ) based on the weight of the hematite particles or iron oxide hydroxide particles as core particles.
  • the coating amount of the hydroxides and/or oxides of aluminum and/or silicon is less than 0.01 % by weight, the effect of enhancing the dispersibility of the obtained black non-magnetic composite particles in a binder resin upon the production of black toner may not be obtained.
  • the coating amount of the hydroxides and/or oxides of aluminum and/or silicon is more than 50 % by weight, the obtained black non-magnetic composite particles can exhibit a good dispersibility in a binder resin upon the production of black toner.
  • the use of such unnecessarily large coating amount of the hydroxides and/or oxides of aluminum and/or silicon is meaningless.
  • the particle size, geometrical standard deviation, BET specific surface area, fluidity, blackness L* value and desorption percentage of carbon black fine particles of the black non-magnetic composite particles wherein the surface of the core particle is coated with the hydroxides and/or oxides of aluminum and/or silicon according to the present invention are substantially the same as those of the black non-magnetic composite particles wherein the core particle is uncoated with the hydroxides and/or oxides of aluminum and/or silicon according to the present invention.
  • the black non-magnetic composite particles according to the present invention can be produced by the following method.
  • the granular hematite particles as the isotropic core particles according to the present invention can be produced by heating, in air at a temperature of 750 to 1,000°C, granular magnetite particles which are obtained by a so-called wet oxidation method, i.e., by passing an oxygen-containing gas through a suspension containing a ferrous hydroxide colloid obtained by reacting an aqueous ferrous salt solution with alkali hydroxide.
  • a so-called wet oxidation method i.e., by passing an oxygen-containing gas through a suspension containing a ferrous hydroxide colloid obtained by reacting an aqueous ferrous salt solution with alkali hydroxide.
  • the granular manganese-containing hematite particles as the isotropic core particles according to the present invention can be produced by heating, in air at a temperature of 750 to 1,000°C, (a) coated magnetite particles which are obtained by first producing granular magnetite particles by a so-called wet oxidation method, i.e., by passing an oxygen-containing gas through a suspension containing a ferrous hydroxide colloid obtained by reacting an aqueous ferrous salt solution with alkali hydroxide, and then coating the obtained granular magnetite particles with a manganese compound in an amount of 8 to 150 atm % (calculated as Mn) based on whole Fe, or (b) magnetite particles containing manganese in an amount of 8 to 150 atm % (calculated as Mn) based on whole Fe, which are obtained by conducting the above wet oxidation method in the presence of manganese.
  • a so-called wet oxidation method i.e., by passing
  • the acicular or spindle-shaped hematite particles as the anisotropic core particles according to the present invention can be produced by heating acicular or spindle-shaped iron oxide hydroxide particles obtained by the method described hereinafter, in air at a temperature of 400 to 800°C.
  • the acicular or spindle-shaped iron oxide hydroxide particles as the anisotropic core particles according to the present invention can be produced by passing an oxygen-containing gas through a suspension containing either ferrous hydroxide colloid, iron carbonate or iron-containing precipitates obtained by reacting an aqueous ferrous salt solution with alkali hydroxide, alkali carbonate or both of alkali hydroxide and alkali carbonate, and then subjecting the obtained iron oxide hydroxide particles to filtration, washing with water and drying.
  • a suspension containing either ferrous hydroxide colloid, iron carbonate or iron-containing precipitates obtained by reacting an aqueous ferrous salt solution with alkali hydroxide, alkali carbonate or both of alkali hydroxide and alkali carbonate
  • the acicular or spindle-shaped manganese-containing hematite particles as the anisotropic core particles according to the present invention can be produced by heating, in air at a temperature of 400 to 800°C, acicular or spindle-shaped iron oxide hydroxide particles containing manganese in an amount of 8 to 150 atomic % based on whole Fe, which are obtained by the method described hereinafter.
  • acicular or spindle-shaped iron oxide hydroxide particles containing manganese in an amount of 8 to 150 atomic % based on whole Fe which are obtained by the method described hereinafter.
  • the acicular or spindle-shaped manganese-containing iron oxide hydroxide particles as the anisotropic core particles according to the present invention can be produced by passing an oxygen-containing gas through a suspension containing either ferrous hydroxide colloid, iron carbonate or iron-containing precipitates obtained by reacting an aqueous ferrous salt solution with alkali hydroxide, alkali carbonate or both of alkali hydroxide and alkali carbonate, in the presence of manganese in an amount of 8 to 150 atm % (calculated as Mn) based on whole Fe, and then subjecting the obtained iron oxide hydroxide particles to filtration, washing with water and drying.
  • substantially whole amount of the alkoxysilane compounds, the polysiloxanes, the modified polysiloxanes, the terminal-modified polysiloxanes or the fluoroalkylsilane compounds added can be applied onto the surfaces of the hematite particles or iron oxide hydroxide particles.
  • the hematite particles or iron oxide hydroxide particles are preliminarily diaggregated by using a pulverizer.
  • a pulverizer As the apparatuses for the mixing and stirring, there may be used an edge runner, a Henschel mixer or the like.
  • the conditions for the mixing and stirring such as mixing ratio, linear load, stirring speed or mixing and stirring time, may be appropriately adjusted so as to coat the surfaces of the hematite particles or iron oxide hydroxide particles with the alkoxysilane compounds, the polysiloxanes, the modified polysiloxanes, the terminal-modified polysiloxanes or the fluoroalkylsilane compounds as uniformly as possible.
  • the mixing and stirring time for the coating treatment is, for example, preferably not less than 20 minutes.
  • the amount of the alkoxysilane compounds, the polysiloxanes, the modified polysiloxanes, the terminal-modified polysiloxanes or the fluoroalkylsilane compounds added is preferably 0.15 to 45 parts by weight based on 100 parts by weight of the hematite particles or iron oxide hydroxide particles.
  • the amount of the organosilicon compounds added is less than 0.15 part by weight, it may become difficult to adhere the carbon black fine particles in such an amount enough to improve the blackness and flowability of the obtained black non-magnetic composite particles.
  • the amount of the organosilicon compounds added is more than 45 parts by weight, a sufficient amount of the carbon black fine particles can be adhered on the surface of the coating, but it is meaningless because the blackness and flowability of the black composite particles cannot be further improved by using such an excess amount of the organosilicon compounds.
  • the carbon black fine particles are added to the hematite particles or iron oxide hydroxide particles coated with the organosilicon compounds, and the resultant mixture is mixed and stirred to adhere the carbon black fine particles on the surfaces of the coating composed of the organosilicon compounds, and then dried or heat-treated.
  • the coating compound In the case where the alkoxysilane compounds (1) and the fluoroalkylsilane compounds (3) are used as the coating compound, after the carbon black fine particles are adhered on the surface of the coating, the resultant composite particles are dried or heat-treated, for example, at a temperature of usually 40 to 200°C, preferably 60 to 150°C for usually 10 minutes to 12 hours, preferably 30 minutes to 3 hours, thereby forming a coating composed of the organosilane compounds (1) and the fluoroalkyl organosilane compounds (3), respectively.
  • carbon black fine particles are added little by little and slowly, especially about 5 to 60 minutes.
  • the conditions for mixing and stirring the hematite particles or iron oxide hydroxide particles coated with the organosilicon compounds and the carbon black fine particles may be appropriately adjusted so as to uniformly adhere the carbon black fine particles on the surface of the coating.
  • the mixing and stirring time for the adhesion treatment is, for example, preferably not less than 20 minutes.
  • the amount of the carbon black fine particles added is preferably 1 to 25 parts by weight based on 100 parts by weight of the hematite particles or iron oxide hydroxide particles.
  • the amount of the carbon black fine particles added is less than 1 part by weight, it may become difficult to adhere the carbon black fine particles in such an amount enough to improve the blackness and flowability of the obtained black non-magnetic composite particles.
  • the amount of the carbon black fine particles added is more than 25 parts by weight, a sufficient blackness and flowability of the resultant black non-magnetic composite particles can be obtained, but the carbon black fine particles tend to be desorbed from the surface of the coating because of too large amount of the carbon black fine particles adhered, resulting in deteriorated dispersibility in the binder resin upon the production of the black toner.
  • At least a part of the surface of the hematite particles or iron oxide hydroxide particles may be coated with at least one compound selected from the group consisting of hydroxides of aluminum, oxides of aluminum, hydroxides of silicon and oxides of silicon, if required, prior to mixing and stirring with the alkoxysilane compounds, the polysiloxanes, the modified polysiloxanes, the terminal-modified polysiloxanes or the fluoroalkylsilane compounds.
  • the coat of the hydroxides and/or oxides of aluminum and/or silicon may be conducted by adding an aluminum compound, a silicon compound or both the compounds to a water suspension in which the hematite particles or iron oxide hydroxide particles are dispersed, followed by mixing and stirring, and further adjusting the pH value of the suspension, if required, thereby coating the surfaces of the hematite particles or iron oxide hydroxide particles with at least one compound selected from the group consisting of hydroxides of aluminum, oxides of aluminum, hydroxides of silicon and oxides of silicon.
  • the thus obtained particles coated with the hydroxides and/or oxides of aluminum and/or silicon are then filtered out, washed with water, dried and pulverized. Further, the particles coated with the hydroxides and/or oxides of aluminum and/or silicon may be subjected to post-treatments such as deaeration treatment and compaction treatment, if required.
  • aluminum compounds there may be exemplified aluminum salts such as aluminum acetate, aluminum sulfate, aluminum chloride or aluminum nitrate, alkali aluminates such as sodium aluminate, alumina sols or the like.
  • the amount of the aluminum compound added is 0.01 to 50 % by weight (calculated as Al) based on the weight of the hematite particles or iron oxide hydroxide particles.
  • the amount of the aluminum compound added is less than 0.01 % by weight, it may be difficult to sufficiently coat the surfaces of the hematite particles or iron oxide hydroxide particles with hydroxides and/or oxides of aluminum, thereby failing to achieve the improvement of the dispersibility in the binder resin upon the production of the black toner.
  • the amount of the aluminum compound added is more than 50 % by weight, the coating effect is saturated and, therefore, it is meaningless to add such an excess amount of the aluminum compound.
  • silicon compounds there may be exemplified #3 water glass, sodium orthosilicate, sodium metasilicate, colloidal silica or the like.
  • the amount of the silicon compound added is 0.01 to 50 % by weight (calculated as SiO 2 ) based on the weight of the hematite particles or iron oxide hydroxide particles.
  • the amount of the silicon compound added is less than 0.01 % by weight, it may be difficult to sufficiently coat the surfaces of the hematite particles or iron oxide hydroxide particles with hydroxides and/or oxides of silicon, thereby failing to achieve the improvement of the dispersibility in the binder resin upon the production of the black toner.
  • the amount of the silicon compound added is more than 50 % by weight, the coating effect is saturated and, therefore, it is meaningless to add such an excess amount of the silicon compound.
  • the total amount of the aluminum and silicon compounds added is preferably 0.01 to 50 % by weight (calculated as a sum of Al and SiO 2 ) based on the weight of the hematite particles or iron oxide hydroxide particles.
  • the black toner according to the present invention comprises the black non-magnetic composite particles, and a binder resin.
  • the black toner may further contain a mold release agent, a colorant, a charge-controlling agent and other additives, if necessary.
  • the black toner according to the present invention has an average particle size of usually 3 to 25 ⁇ m, preferably 4 to 18 ⁇ m, more preferably 5 to 15 ⁇ m.
  • the amount of the binder resin used in the black toner is usually 50 to 3500 parts by weight, preferably 50 to 2000 parts by weight, more preferably 50 to 1000 parts by weight based on 100 parts by weight of the black non-magnetic composite particles.
  • binder resins there may be used vinyl-based polymers, i.e., homopolymers or copolymers of vinyl-based monomers such as styrene, alkyl acrylates and alkyl methacrylates.
  • vinyl-based polymers i.e., homopolymers or copolymers of vinyl-based monomers such as styrene, alkyl acrylates and alkyl methacrylates.
  • styrene monomers there may be exemplified styrene and substituted styrenes.
  • alkyl acrylate monomers there may be exemplified acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate or the like.
  • the above copolymers contain styrene-based components in an amount of usually 50 to 95 % by weight.
  • the above-mentioned vinyl-based polymers may be used in combination with polyester-based resins, epoxy-based resins, polyurethane-based resins or the like.
  • the fluidity index is usually 70 to 100, preferably 71 to 100, more preferably 72 to 100.
  • the fluidity index is less than 70, the black toner may not show a sufficient fluidity.
  • the blackness of the black toner according to the present invention is usually not more than 20, preferably not more than 19.8, more preferably not more than 19.5 when represented by L* value. When the blackness thereof is more than 20, the lightness of the black toner may be increased, resulting in insufficient blackness.
  • the lower limit of the blackness of the black toner is usually about 15 when represented by L* value.
  • the volume resistivity of the black toner according to the present invention is usually not less than 1.0 ⁇ 10 13 ⁇ cm, preferably not less than 3.0 x 10 13 ⁇ cm, more preferably not less than 5.0 x 10 13 ⁇ cm and less than 1.0 x 10 17 ⁇ cm.
  • the volume resistivity is less than 1.0 x 10 13 ⁇ cm, the charge amount of the black toner tends to vary depending upon environmental conditions in which the toner is used, resulting in unstable properties of the black toner.
  • the black toner according to the present invention may be produced by a known method of mixing and kneading a predetermined amount of a binder resin and a predetermined amount of the black non-magnetic composite particles together, and then pulverizing the mixed and kneaded material into particles. More specifically, the black non-magnetic composite particles and the binder resin are intimately mixed together with, if necessary, a mold release agent, a colorant, a charge-controlling agent or other additives by using a mixer. The obtained mixture is then melted and kneaded by a heating kneader, thereby dispersing the black non-magnetic composite particles in the binder resin. Successively, the molten mixture is cooled and solidified to obtain a resin mixture. The obtained resin mixture is then pulverized and classified, thereby producing a black toner having an aimed particle size.
  • the mixers there may be used a Henschel mixer, a ball mill or the like.
  • the heating kneaders there may be used a roll mill, a kneader, a twin-screw extruder or the like.
  • the pulverization of the resin mixture may be conducted by using pulverizers such as a cutter mill, a jet mill or the like.
  • the classification of the pulverized particles may be conducted by known methods such as air classification, etc., as described in Japanese Patent No. 2683142 or the like.
  • the other method of producing the black toner there may be exemplified a suspension polymerization method or an emulsion polymerization method.
  • the suspension polymerization method polymerizable monomers and the black non-magnetic composite particles are intimately mixed together with, if necessary, a colorant, a polymerization initiator, a cross-linking agent, a charge-controlling agent or the other additives and then the obtained mixture is dissolved and dispersed together so as to obtain a monomer composition.
  • the obtained monomer composition is added to a water phase containing a suspension stabilizer while stirring, thereby granulating and polymerizing the composition to form black toner particles having an aimed particle size.
  • the monomers and the black non-magnetic composite particles are dispersed in water together with, if necessary, a colorant, a polymerization initiator or the like and then the obtained dispersion is polymerized while adding an emulsifier thereto, thereby producing black toner particles having an aimed particle size.
  • the black non-magnetic composite particles comprising the hematite particles or iron oxide hydroxide particles as the core particles, which have an average particle diameter of 0.055 to 0.95 ⁇ m and which may be coated with at least one compound selected from the group consisting of hydroxides of aluminum, oxides of aluminum, hydroxides of silicon and oxides of silicon; the organosilicon compounds coated on the surface of the hematite particle or iron oxide hydroxide particle; the carbon black fine particles having an average particle size of 0.002 to 0.05 ⁇ m, which are adhered on the surface of the coating composed of the organosilicon compounds, in which the total amount of the carbon black fine particles adhered to the coating composed of the organosilicon compounds is 1 to 25 parts by weight based on 100 parts by weight of the hematite particles or iron oxide hydroxide particles, can show not only excellent fluidity and blackness, but also an excellent dispersibility in a binder resin upon the production of a black toner due to less amount of carbon black
  • the reason why the amount of the carbon black fine particles desorbed (or fallen-off) from the surfaces of the black non-magnetic composite particles according to the present invention, is small, is considered as follows. That is, the surfaces of the hematite particles or iron oxide hydroxide particles as the core particles and the organosilicon compounds are strongly bonded to each other, so that the carbon black fine particles bonded to the surfaces of the hematite particles or iron oxide hydroxide particles through the organosilicon compounds can be prevented from being desorbed from the hematite particles or iron oxide hydroxide particles.
  • metallosiloxane bonds ( ⁇ Si-O-M wherein M represents a metal atom contained in the hematite particles or iron oxide hydroxide particles as the core particles, such as Si, Al, Fe or the like) are formed between the surfaces of the hematite particles or iron oxide hydroxide particles and alkoxy groups contained in the organosilicon compounds onto which the carbon black fine particles are adhered, thereby forming a stronger bond between the organosilicon compounds on which the carbon black fine particles are adhered, and the surfaces of the hematite particles or iron oxide hydroxide particles.
  • the reason why the amount of the carbon black fine particles desorbed (or fallen-off) from the surfaces of the black non-magnetic composite particles according to the present invention, is small, is considered as follows. That is, the surfaces of the hematite particles or iron oxide hydroxide particles and the organosilicon compounds are strongly bonded to each other, so that the carbon black fine particles bonded to the surfaces of the hematite particles or iron oxide hydroxide particles through the organosilicon compounds can be prevented from being desorbed from the hematite particles or iron oxide hydroxide particles.
  • the reason why the black non-magnetic composite particles according to the present invention can show an excellent dispersibility in a binder resin upon the production of black toner, is considered such that since only a small amount of the carbon black fine particles are desorbed (or fallen-off) from the surfaces of the black non-magnetic composite particles, the black non-magnetic composite particles is free from deterioration in dispersibility due to the desorbed (or fallen-off) carbon black fine particles, and further since the carbon black fine particles are adhered onto the surfaces of the black non-magnetic composite particles and, therefore, irregularities are formed on the surfaces of the black non-magnetic composite particles, the contact between the particles can be suppressed.
  • the black non-magnetic composite particles according to the present invention can show an excellent fluidity, is considered as follows. That is, the carbon black fine particles which are ordinarily agglomerated together due to fineness thereof, are allowed to be uniformly and densely adhered on the surfaces of the hematite particles or iron oxide hydroxide particles as the core particles and, therefore, can be dispersed nearly in the form of primary particles, so that many fine irregularities are formed on the surfaces of the hematite particles or iron oxide hydroxide particles.
  • the reason why the black non-magnetic composite particles according to the present invention can show an excellent blackness, is considered such that since the carbon black fine particles are uniformly and densely adhered on the surfaces of the hematite particles or iron oxide hydroxide particles as the core particles, the color tone of the core particles is hidden behind the carbon black fine particles, so that an inherent color tone of carbon black can be exhibited.
  • the black toner produced by using the above black non-magnetic composite particles can show excellent fluidity and blackness.
  • the reason why the black toner according to the present invention can show an excellent fluidity is considered as follows. That is, the black non-magnetic composite particles on which a large amount of the carbon black fine particles are uniformly adhered, are blended in the black toner, so that many fine irregularities are formed on the surface of the black toner.
  • the reason why the black toner according to the present invention can show an excellent blackness is considered such that the black non-magnetic composite particles having an excellent blackness is blended in the black toner.
  • the black non-magnetic composite particles according to the present invention are excellent not only in fluidity and blackness, but also in dispersibility in a binder resin due to less amount of the carbon black fine particles desorbed or ( fallen-off) from the surfaces thereof, the black non-magnetic composite particles according to the present invention, are suitable as black non-magnetic composite particles for black toner capable of attaining a high image quality and a high copying speed.
  • the black non-magnetic composite particles according to the present invention are excellent in dispersibility in a binder resin, the particles can show excellent handling property and workability and, therefore, are preferable from an industrial viewpoint.
  • the black toner produced from the above black non-magnetic composite particles which are excellent in fluidity and blackness can also show excellent fluidity and blackness. Accordingly, the black toner is suitable as black toner capable of attaining a high image quality and a high copying speed.
  • the black toner according to the present invention since the black non-magnetic composite particles contained therein are excellent in dispersibility, it is possible to expose the black non-magnetic composite particles to the surface of the black toner independently and separately. As a result, the black toner can be free from being deteriorated in electric resistance due to the existence of the carbon black fine particles. Accordingly, the black toner according to the present invention is suitable as a high-resistance or insulated black toner.
  • the thus obtained cylindrical test piece was exposed to an atmosphere maintained at a temperature of 25°C and a relative humidity of 60 % for 12 hours. Thereafter, the cylindrical test piece was set between stainless steel electrodes, and a voltage of 15V was applied between the electrodes using a Wheatstone bridge (TYPE2768, manufactured by Yokogawa-Hokushin Denki Co., Ltd.) to measure a resistance value R ( ⁇ ).
  • TYPE2768 manufactured by Yokogawa-Hokushin Denki Co., Ltd.
  • the cylindrical test piece was measured with respect to an upper surface area A (cm 2 ) and a thickness t 0 (cm) thereof.
  • the measured values were inserted into the following formula, thereby obtaining a volume resistivity X ( ⁇ cm).
  • X ( ⁇ cm) R x (A/t 0 )
  • the obtained slurry containing the granular-shaped Mn-containing hematite particles was passed through a transverse-type sand grinder (tradename "MIGHTY MILL MHG-1.5L", manufactured by Inoue Seisakusho Co., Ltd.) five times at an axis-rotating speed of 2,000 rpm, thereby obtaining a slurry in which the granular-shaped Mn-containing hematite particles were dispersed.
  • a transverse-type sand grinder tradename "MIGHTY MILL MHG-1.5L", manufactured by Inoue Seisakusho Co., Ltd.
  • the particles in the obtained slurry which remained on a sieve of 325 meshes (mesh size: 44 ⁇ m) was 0 %.
  • the slurry was filtered and washed with water, thereby obtaining a filter cake containing the granular-shaped Mn-containing hematite particles.
  • MPUV-2 Model tradename, manufactured by Matsumoto Chuzo Tekkosho Co., Ltd.
  • methyl triethoxysilane 110 g was mixed and diluted with 200 ml of ethanol to obtain a methyl triethoxysilane solution.
  • the methyl triethoxysilane solution was added to the deagglomerated granular-shaped Mn-containing hematite particles under the operation of the edge runner.
  • the granular-shaped Mn-containing hematite particles were continuously mixed and stirred at a linear load of 60 Kg/cm for 60 minutes.
  • the obtained black non-magnetic composite particles were aged at 105°C for 60 minutes by using a drier to evaporate water, ethanol or the like which were remained on surfaces of the black non-magnetic composite particles.
  • the resultant black non-magnetic composite particles had an average particle diameter of 0.31 ⁇ m.
  • the black non-magnetic composite particles showed a geometrical standard deviation value of 1.46, a BET specific surface area value of 9.1 m 2 /g, a fluidity index of 48 and a blackness (L* value) of 17.6.
  • the desorption percentage of the carbon black fine particles from the black non-magnetic composite particles was 6.6 %.
  • the coating amount of an organosilane compound produced from methyl triethoxysilane was 0.16 % by weight, calculated as Si. Since no independent carbon black fine particles were observed on the electron micrograph of Fig. 3, it was determined that a whole amount of the carbon black fine particles were adhered on the coating composed of the organosilane compound produced from methyl triethoxysilane.
  • the obtained mixed particles were melt-kneaded at 140°C using a continuous-type twin-screw kneader (T-1), and the obtained kneaded material was cooled, coarsely pulverized and finely pulverized in air. The obtained particles were subjected to classification, thereby producing a black toner.
  • T-1 continuous-type twin-screw kneader
  • the obtained black toner had an average particle diameter of 10.1 pm, a dispersibility of 5th rank, a fluidity index of 75, a blackness (L* value) of 18.6, a volume resistivity of 1.2 x 10 14 ⁇ cm.
  • the obtained slurry containing the granular-shaped Mn-containing hematite particles was passed through a transverse-type sand grinder (tradename "MIGHTY MILL MHG-1.5L", manufactured by Inoue Seisakusho Co., Ltd.) five times at an axis-rotating speed of 2,000 rpm, thereby obtaining a slurry in which the granular-shaped Mn-containing hematite particles were dispersed.
  • a transverse-type sand grinder tradename "MIGHTY MILL MHG-1.5L", manufactured by Inoue Seisakusho Co., Ltd.
  • the particles in the obtained slurry which remained on a sieve of 325 meshes (mesh size: 44 ⁇ m) was 0 %.
  • the slurry was filtered and washed with water, thereby obtaining a filter cake containing the granular-shaped Mn-containing hematite particles.
  • MPUV-2 Model tradename, manufactured by Matsumoto Chuzo Tekkosho Co., Ltd.
  • methyl hydrogen polysiloxane (tradename: "TSF484", produced by Toshiba Silicone Co., Ltd.) were added to the deagglomerated granular-shaped Mn-containing hematite particles under the operation of the edge runner.
  • the granular-shaped Mn-containing hematite particles were continuously mixed and stirred at a linear load of 60 Kg/cm for 60 minutes.
  • the obtained black non-magnetic composite particles were dried at 105°C for 60 minutes by using a drier to evaporate water or the like which were remained on surfaces of the black non-magnetic composite particles.
  • the obtained black non-magnetic composite particles had an average particle diameter of 0.31 ⁇ m.
  • the black non-magnetic composite particles had a geometrical standard deviation value of 1.46, a BET specific surface area value of 8.9 m 2 /g, a fluidity index of 46 and a blackness (L* value) of 18.2.
  • the desorption percentage of the carbon black fine particles from the black non-magnetic composite particles was 6.4 %.
  • the coating amount of methyl hydrogen polysiloxane was 0.41 % by weight, calculated as Si. Since no independent carbon black fine particles were observed on the electron micrograph, it was determined that a whole amount of the carbon black fine particles were adhered on the coating composed of methyl hydrogen polysiloxane.
  • the obtained mixed particles were melt-kneaded at 140°C using a continuous-type twin-screw kneader (T-1), and the obtained kneaded material was cooled, coarsely pulverized and finely pulverized in air. The obtained particles were subjected to classification, thereby producing a black toner.
  • T-1 continuous-type twin-screw kneader
  • the obtained black toner had an average particle diameter of 10.1 ⁇ m, a dispersibility of 5th rank, a fluidity index of 73, a blackness (L* value) of 19.7, a volume resistivity of 9.6 x 10 14 ⁇ cm.
  • the obtained slurry containing the granular-shaped Mn-containing hematite particles was passed through a transverse-type sand grinder (tradename "MIGHTY MILL MHG-1.5L", manufactured by Inoue Seisakusho Co., Ltd.) five times at an axis-rotating speed of 2,000 rpm, thereby obtaining a slurry in which the granular-shaped Mn-containing hematite particles were dispersed.
  • a transverse-type sand grinder tradename "MIGHTY MILL MHG-1.5L", manufactured by Inoue Seisakusho Co., Ltd.
  • the particles in the obtained slurry which remained on a sieve of 325 meshes (mesh size: 44 ⁇ m) was 0 %.
  • the slurry was filtered and washed with water, thereby obtaining a filter cake containing the granular-shaped Mn-containing hematite particles.
  • MPUV-2 Model tradename, manufactured by Matsumoto Chuzo Tekkosho Co., Ltd.
  • the mixed particles were continuously stirred at a linear load of 60 Kg/cm for 60 minutes to adhere the carbon black fine particles on the coating composed of tridecafluorooctyl trimethoxysilane, thereby obtaining black non-magnetic composite particles.
  • the obtained black non-magnetic composite particles were aged at 105°C for 60 minutes by using a drier to evaporate water or the like which were remained on surfaces of the black non-magnetic composite particles.
  • the obtained black non-magnetic composite particles had an average particle diameter of 0.31 ⁇ m.
  • the black non-magnetic composite particles showed a geometrical standard deviation value of 1.45, a BET specific surface area value of 5.0 m 2 /g, a fluidity index of 49 and a blackness (L* value) of 17.8.
  • the desorption percentage of the carbon black fine particles from the black non-magnetic composite particles was 6.5 %.
  • the coating amount of a fluoroalkyl organosilane compound produced from tridecafluorooctyl trimethoxysilane was 0.10 % by weight, calculated as Si. Since no independent carbon black fine particles were observed on the electron micrograph, it was determined that a whole amount of the carbon black fine particles were adhered on the coating composed of the fluoroalkyl organosilane compound produced from tridecafluorooctyl trimethoxysilane.
  • the obtained mixed particles were melt-kneaded at 140°C using a continuous-type twin-screw kneader (T-1), and the obtained kneaded material was cooled, coarsely pulverized and finely pulverized in air. The obtained particles were subjected to classification, thereby producing a black toner.
  • T-1 continuous-type twin-screw kneader
  • the obtained black toner had an average particle diameter of 10.0 ⁇ m, a dispersibility of 5th rank, a fluidity index of 76, a blackness (L* value) of 19.2, a volume resistivity of 2.8 ⁇ 10 14 ⁇ cm.
  • Core particles 1 to 4 are Core particles 1 to 4:
  • Various hematite particles or iron oxide hydroxide particles were prepared by known methods. The same procedure as defined in Example 1 was conducted by using the thus prepared particles, thereby obtaining deagglomerated hematite particles or iron oxide hydroxide particles as core particles.
  • Example 2 The same procedure as defined in Example 1 was conducted by using 20 kg of the deagglomerated granular-shaped Mn-containing hematite particles (core particles 1) and 150 liters of water, thereby obtaining a slurry containing the granular-shaped Mn-containing hematite particles.
  • the pH value of the obtained re-dispersed slurry containing the granular-shaped Mn-containing hematite particles was adjusted to 10.5 by adding an aqueous sodium solution, and then the concentration of the slurry was adjusted to 98 g/liter by adding water thereto.
  • Example 2 The same procedure as defined in Example 1 was conducted except that kind of hematite particles or iron oxide hydroxide particles to be treated, addition or non-addition of an alkoxysilane compound in the coating treatment with alkoxysilane compound, kind and amount of the alkoxysilane compound added, treating conditions of edge runner in the coating treatment, kind and amount of carbon black fine particles adhered, and treating conditions of edge runner used in the adhering process of the carbon black fine particles, were varied, thereby obtaining black non-magnetic composite particles.
  • the black non-magnetic composite particles obtained in Examples 7 to 14 were observed by an electron microscope. As a result, almost no independent carbon black fine particles were recognized. Therefore, it was confirmed that a substantially whole amount of the carbon black fine particles were adhered on the coating composed of organosilane compound produced from the alkoxysilane compound.
  • Example 2 The same procedure as defined in Example 2 was conducted by using the black non-magnetic composite particles obtained in Examples 7 to 14, the core particles 1 to 4, the carbon black fine particles A to C, the mixed particles composed of the granular-shaped Mn-containing hematite particles and the carbon black fine particles used in Comparative Example 1, and the black non-magnetic particles obtained in Comparative Examples 2 to 5, thereby obtaining black toners.
  • Example 3 The same procedure as defined in Example 3 was conducted except that kind of hematite particles or iron oxide hydroxide particles to be treated, addition or non-addition of a polysiloxane or modified polysiloxane, kind and amount of the polysiloxane or modified polysiloxane, treating conditions of edge runner in the coating treatment, kind and amount of carbon black fine particles adhered, and treating conditions of edge runner used in the adhering process of the carbon black fine particles, were varied, thereby obtaining black non-magnetic composite particles.
  • the black non-magnetic composite particles obtained in Examples 23 to 46 were observed by an electron microscope. As a result, almost no independent carbon black fine particles were recognized. Therefore, it was confirmed that a substantially whole amount of the carbon black fine particles were adhered on the coating composed of polysiloxane or modified polysiloxane.
  • Example 4 The same procedure as defined in Example 4 was conducted by using the black non-magnetic particles obtained in Examples 47 to 70, and the black non-magnetic composite particles obtained in Comparative Examples 18 to 26, thereby obtaining black toners.
  • Example 5 The same procedure as defined in Example 5 was conducted except that kind of hematite particles or iron oxide hydroxide particles to be treated, addition or non-addition of a fluoroalkyl organosilane compound, kind and amount of the fluoroalkyl organosilane compound added, treating conditions of edge runner in the coating treatment, kind and amount of carbon black fine particles adhered, and treating conditions of edge runner used in the adhering process of the carbon black fine particles, were varied, thereby obtaining black non-magnetic composite particles.
  • the black non-magnetic composite particles obtained in Examples 71 to 78 were observed by an electron microscope. As a result, almost no independent carbon black fine particles were recognized. Therefore, it was confirmed that a substantially whole amount of the carbon black fine particles were adhered on the coating composed of a fluoroalkyl organosilane compound produced from the fluoroalkylsilane compound.
  • Example 6 The same procedure as defined in Example 6 was conducted by using the black non-magnetic particles obtained in Examples 71 to 78, and the black non-magnetic composite particles obtained in Comparative Examples 36 to 38, thereby obtaining black toners.

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Claims (24)

  1. Schwarze nicht-magnetische Kompositteilchen für eine schwarze Tonerzusammensetzung, die folgendes umfassen:
    (a) Hämatit- und/oder Eisenoxidhydroxidteilchen mit einem durchschnittlichen Teilchendurchmesser von 0,055-0,95 µm;
    (b) eine Beschichtung auf der Oberfläche der Hämatit- und/oder Eisenoxidhydroxidteilchen, die mindestens eine Organosiliciumverbindung umfasst, ausgewählt aus:
    (1 Organosilanverbindungen, die erhältlich sind durch Trocknen oder Wärmebehandeln von Alkoxysilanverbindungen,
    (2) Polysiloxanen oder modifizierten Polysiloxanen, und
    (3) Fluoralkylorganosilanverbindungen, die erhältlich sind durch Trocknen oder Wärmebehandeln von Fluoralkylsilanverbindungen; und
    (c) auf der Beschichtung anhaftende feine Russteilchen, worin der anhaftende Russ erhältlich ist durch Vermischen und Verrühren von 1-25 Gew.-Teilen, bezogen auf 100 Gew.-Teile der Hämatit- und/oder Eisenoxidhydroxidteilchen, feiner Russteilchen mit einer durchschnittlichen Teilchengrösse von 0,002-0,05 µm mit den Hämatit- und/oder Eisenoxidhydroxidteilchen mit einer Oberflächenbeschichtung aus der Alkoxysilanverbindung, dem Polysiloxan oder modifizierten Polysiloxan und/oder der Fluoralkylsilanverbindung.
  2. Teilchen gemäss Anspruch 1, worin die Hämatit- und/oder Eisenoxidhydroxidteilchen eine Beschichtung auf mindestens einem Teil ihrer Oberfläche aufweisen, die mindestens ein Hydroxid oder Oxid umfasst, ausgewählt aus Hydroxiden oder Oxiden von entweder Aluminium oder Silicium in einer Menge von 0,01-50 Gew.%, berechnet als Al und/oder SiO2, auf Basis des Gesamtgewichts der Hämatit- und/oder Eisenoxidhydroxidteilchen.
  3. Teilchen gemäss Anspruch 1 oder 2, worin die Alkoxysilanverbindung durch die allgemeine Formel (I) repräsentiert wird: R1 aSiX4-a worin R1 C6H5-, (CH3)2CHCH2- oder n-CbH2b+1- (worin b eine ganze Zahl von 1-18 ist) darstellt; X ist CH3Ooder C2H5O- ; und a eine ganze Zahl von 0-3.
  4. Teilchen gemäss Anspruch 3, worin die Alkoxysilanverbindung Methyltriethoxysilan,. Dimethyldiethoxysilan, Tetraethoxysilan, Phenyltriethoxysilan, Diphenyldiethoxysilan, Methyltrimethoxysilan, Dimethyldimethoxysilan, Tetramethoxysilan, Phenyltrimethoxysilan, Diphenyldimethoxysilan, Isobutyltrimethoxysilan oder Decyltrimethoxysilan ist.
  5. Teilchen gemäss einem der vorhergehenden Ansprüche, worin die Polysiloxane durch die allgemeine Formel (II) repräsentiert werden:
    Figure 01270001
    worin R2 H- oder CH3- ist, und d ist eine ganze Zahl von 15-450.
  6. Teilchen gemäss Anspruch 5, worin die Polysiloxane Methylwasserstoffsiloxan-Einheiten aufweisen.
  7. Teilchen gemäss mindestens einem der vorhergehenden Ansprüche, worin die modifizierten Polysiloxane ausgewählt sind aus:
    (A) Polysiloxanen, die mit mindestens eine(m/r) Polyether und/oder Polyester und/oder Epoxyverbindung modifiziert sind, und
    (B) Polysiloxanen, deren Molekülende mit mindestens einer Gruppe, ausgewählt aus Carbonsäure-, Alkohol- und Hydroxylgruppen, modifiziert ist.
  8. Teilchen gemäss Anspruch 7, worin die mit mindestens eine(m/r) Polyether und/oder Polyester und/oder Epoxyverbindung modifizierten Polysiloxan durch die folgende Formel (III), (IV) oder (V) repräsentiert werden:
    Figure 01280001
    worin R3 -(CH2)h- ist; R4 ist -(CH2)i-CH3; R5 ist -OH, -COOH, -CH=CH2, -C(CH3)=CH2 oder -(CH2)j-CH3; R6 ist - (CH2)k-CH3; g und h sind ganze Zahlen von 1-15; i, j und k sind ganze Zahlen von 0-15; e ist eine ganze Zahl von 1-50; und f ist eine ganze Zahl von 1-300;
    Figure 01280002
    worin R7, R8 und R9 -(CH2)q- sind und identisch oder voneinander verschieden sein können; R10 ist -OH, -COOH, -CH=CH2, -C(CH3)=CH2 oder -(CH2)r-CH3; R11 ist -(CH2)s-CH3; n und q sind ganze Zahlen von 1-15; r und s sind ganze Zahlen von 0-15; e' ist eine ganze Zahl von 1-50; und f' ist eine ganze Zahl von 1-300; oder
    Figure 01280003
    worin R12 -(CH2)v- ist; v ist eine ganze Zahl von 1-15; t ist eine ganze Zahl von 1-50; und u ist eine ganze Zahl von 1-300.
  9. Teilchen gemäss Anspruch 7 oder 8, worin die Polysiloxane, deren Molekülende mit mindestens einer Gruppe, ausgewählt aus Carbonsäure-, Alkohol- und Hydroxylgruppen, modifiziert ist, durch die allgemeine Formel (VI) repräsentiert werden:
    Figure 01290001
    worin R13 und R14 -OH, R16OH oder R17COOH sind und identisch oder voneinander verschieden sein können;, R15 ist -CH3 oder -C6H5; R16 und R17 sind -(CH2)y-; y ist eine ganze Zahl von 1-15; w ist eine ganze Zahl von 1-200; und x ist eine ganze Zahl von 0-100.
  10. Teilchen gemäss mindestens einem der vorhergehenden Ansprüche, worin die Fluoralkylsilanverbindungen durch die allgemeine Formel (VII) repräsentiert sind: CF3(CF2)zCH2CH2(R18)a'SiX4-a' worin R18 -CH3-, -C2H5-, -CH3O- oder -C2H5O- ist; X ist CH3O- oder C2H5O-; und z ist eine ganze Zahl von 0-15 und a' ist eine ganze Zahl von 0-3.
  11. Teilchen gemäss mindestens einem der vorhergehenden Ansprüche, worin die Menge der Organosilicium-Beschichtungsverbindung(en) 0,02-5,0 Gew.%, berechnet als Si, auf Basis des Gesamtgewichts der Organosiliciumverbindung(en) und der Hämatit- oder Eisenoxidhydroxidteilchen beträgt.
  12. Teilchen gemäss mindestens einem der vorhergehenden Ansprüche, die einen durchschnittlichen Teilchendurchmesser von 0,06-1,0 um aufweisen.
  13. Teilchen gemäss mindestens einem der vorhergehenden Ansprüche, die eine geometrische Standardabweichung des Teilchendurchmessers von 1,01-2,0 aufweisen.
  14. Teilchen gemäss mindestens einem der vorhergehenden Ansprüche, die eine BET-spezifische Oberfläche von 1-200 m2/g aufweisen.
  15. Teilchen gemäss mindestens einem der vorhergehenden Ansprüche, die einen Fliessindex von 45-80 aufweisen.
  16. Teilchen gemäss mindestens einem der vorhergehenden Ansprüche, die einen Schwarzgrad (L*-Wert) von 15-20 aufweisen.
  17. Verfahren zur Herstellung schwarzer nicht-magnetischer Kompositteilchen gemäss Anspruch 1, das folgendes umfasst:
    (a) Vermischen und Verrühren der Hämatit- und/oder Eisenoxidhydroxidteilchen mit mindestens einer siliciumhaltigen Verbindung, ausgewählt aus:
    (1) Alkoxysilanverbindungen,
    (2) Polysiloxanen oder modifizierten Polysiloxanen und
    (3) Fluoralkylsilanverbindungen,
    wodurch die Oberfläche der Hämatit- oder Eisenoxidhydroxidteilchen mit der Verbindung beschichtet wird;
    (b) Zugabe feiner Russteilchen mit einer durchschnittlichen Teilchengrösse von 0,002-0,05 µm in einer Menge von 1-25 Gew.-Teilen auf Basis von 100 Gew.-Teilen der Hämatit- oder Eisenoxidhydroxidteilchen, wodurch gemischte Teilchen erhalten werden;
    (c) Vermischen und Verrühren der gemischten Teilchen; und
    (d) Trocknen oder Wärmebehandeln, wodurch der Russ auf der Oberfläche der die Organosiliciumverbindung umfassenden Beschichtung angehaftet werden.
  18. Schwarze Tonerzusammensetzung, die folgendes umfasst:
    ein Binderharz und schwarze nicht-magnetische Kompositteilchen gemäss mindestens einem der Ansprüche 1 bis 16.
  19. Toner gemäss Anspruch 18, der 50-3.500 Gew.-Teile Binderharz pro 100 Gew.-Teile der schwarzen nicht-magnetischen Kompositteilchen umfasst.
  20. Toner gemäss Anspruch 18 oder 19, der einen durchschnittlichen Teilchendurchmesser von 3-25 µm aufweist.
  21. Toner gemäss mindestens einem der Ansprüche 18 bis 20, der einen Fliesindex von 70-100 aufweist.
  22. Toner gemäss mindestens einem der Ansprüche 18 bis 21, der einen Schwarzgrad (L*-Wert) von 15-20 besitzt.
  23. Toner gemäss mindestens einem der Ansprüche 18 bis 22, der einen Volumenwiderstand von nicht weniger als 1,0 x 1013 Ω·cm aufweist.
  24. Verfahren zur Herstellung eines schwarzen Toners, das das Vermischen von schwarzen nicht-magnetischen Kompositteilchen gemäss mindestens einem der Ansprüche 1 bis 16 mit einem Binderharz und die Verarbeitung der resultierenden Mischung unter Bildung des Toners. umfasst.
EP19990302317 1998-03-26 1999-03-25 Schwarze nicht-magnetische zusammengesetzte Teilchen für schwarze Toner und schwarze Toner, worin sie eingesetzt werden Expired - Lifetime EP0945766B1 (de)

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US6420030B1 (en) 1997-10-31 2002-07-16 Toda Kogyo Corporation Black iron-based composite particles, process for producing the same, paint and rubber or resin composition containing the same
JP4366551B2 (ja) * 1999-08-03 2009-11-18 戸田工業株式会社 磁気記録媒体の非磁性下地層用針状非磁性粒子粉末並びに磁気記録媒体
US6352776B1 (en) 1997-12-12 2002-03-05 Toda Kogyo Corporation Magnetic recording medium, non-magnetic acicular black iron-based composite particles and process for producing the particles
EP1102245A1 (de) * 1999-11-15 2001-05-23 Toda Kogyo Corporation Schwarzes Füllmaterial und dieses enthaltendes magnetisches Aufzeichnungsmedium
JP2002087821A (ja) * 2000-07-14 2002-03-27 Toda Kogyo Corp 黒色トナー用黒色非磁性粒子粉末及び該黒色非磁性粒子粉末を用いた黒色トナー
US6677093B2 (en) 2000-11-01 2004-01-13 Fuji Xerox Co., Ltd. Electrophotographic black toner, electrophotographic developer and image forming method
JP2003057879A (ja) * 2001-06-07 2003-02-28 Toda Kogyo Corp 黒色トナー用黒色複合粒子粉末及び黒色トナー、該黒色トナーを用いた現像方式

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JPS6038701B2 (ja) * 1979-05-08 1985-09-02 キヤノン株式会社 磁性トナ−
JPH0297968A (ja) * 1988-10-05 1990-04-10 Canon Inc 磁性トナー
JP2901697B2 (ja) * 1990-04-18 1999-06-07 戸田工業株式会社 樹脂用耐老化性鉄系着色剤
US5324571A (en) * 1992-02-05 1994-06-28 Konica Corporation Magnetic recording medium comprising a support and a plurality of layers in which the magnetic layer has a specified plastic deformation
JP2872227B2 (ja) * 1992-08-07 1999-03-17 戸田工業株式会社 磁気記録媒体用下地層

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