Magnetic Carrier Patents (Class 430/111.3)
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Patent number: 8420285Abstract: A coated carrier regenerating method in accordance with the present invention includes the step of: determining an amount of a worn-away coating resin of a used coated carrier. Accordingly, an amount of the coating resin layer to be supplemented, namely an amount of the coating resin with which the coating resin layer is to be supplementarily coated is found based on this amount of the worn-away coating resin, whereby the supplementary coating of the used coated carrier can be carried out with the coating resin in the amount thus determined. This allows regeneration of a coated carrier in which a coating resin has a uniform thickness, that is, a coating resin layer has a thickness which is unchanged from the thickness obtained before use of the coated carrier, without the need of completely removing the coating resin from the used coated carrier.Type: GrantFiled: June 23, 2010Date of Patent: April 16, 2013Assignee: Sharp Kabushiki KaishaInventor: Takeshi Kato
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Patent number: 8399171Abstract: A manufacturing apparatus provided with a rotary stirring section and a powder passage is used to manufacture the resin-layer coated carrier. At a fine resin particle adhering step, a magnetic base particle and a fine resin particle are inputted into the powder passage with the rotary stirring section rotating and the fine resin particle is adhered onto the surface of the magnetic base particle. At a spraying step, at least a liquid that plasticizes the fine resin particles is sprayed with spray gas from a spraying section on the magnetic base particle and the fine resin particle which are in a fluidized state in the powder passage. At a film-forming step, rotation by the rotary stirring section is continued to fluidize the magnetic base particles and the fine resin particles until the fine resin particles adhered to the magnetic base particles are softened to form a film.Type: GrantFiled: June 2, 2010Date of Patent: March 19, 2013Assignee: Sharp Kabushiki KaishaInventors: Takashi Hara, Yoshiaki Akazawa, Yoshitaka Kawase, Yoritaka Tsubaki, Yoshinori Mutoh, Keiichi Kikawa
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Publication number: 20130065171Abstract: A latent electrostatic image developing carrier including: core particles each having magnetism; and a coating layer covering each of the core particles, wherein the latent electrostatic image developing carrier has a shape factor SF-2 of 115 to 150 and has a bulk density of 1.8 g/cm3 to 2.4 g/cm3, wherein the core particles have a shape factor SF-2 of 120 to 160 and have an arithmetic mean surface roughness Ra of 0.5 ?m to 1.0 ?m, and wherein the coating layer contains a resin and a filler and an amount of the filler contained in the coating layer is 50 parts by mass to 500 parts by mass per 100 parts by mass of the resin contained in the coating layer.Type: ApplicationFiled: August 23, 2012Publication date: March 14, 2013Inventors: Shigenori Yaguchi, Kimitoshi Yamaguchi, Toyoshi Sawada, Hitoshi Iwatsuki, Toyoaki Tano, Hiroshi Tohmatsu
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Patent number: 8367293Abstract: A method for producing a carrier, including a step of periodically forming and discharging liquid droplets of a carrier core composition liquid from a plurality of nozzles formed in a thin film, using a liquid droplet forming unit having the thin film and a ring-shaped vibration generating unit disposed in a deformable area of the thin film so as to be along a circumference of the area and to vibrate the thin film, a step of forming carrier core particles by solidifying the discharged liquid droplets, and a step of coating the carrier core particles with a resin layer.Type: GrantFiled: December 18, 2008Date of Patent: February 5, 2013Assignee: Ricoh Company, Ltd.Inventors: Shinji Ohtani, Ryota Inoue, Yoshihiro Norikane
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Patent number: 8298669Abstract: A coated carrier that peeling and wearing of a coating layer are hard to be generated and a method of manufacturing the coated carrier are provided. The coated carrier includes a core particle including a magnetic body, a first resin layer coating the core particle, a resin particle layer including a resin particle fixed to the first resin layer as a single layer, and a second resin layer. The first resin layer includes a first resin having a first reactive group. The resin particle layer is formed of resin particles including a cross-linking resin having a second reactive group which can undergo a cross-linking reaction with the first reactive group. The second resin layer is provided so as to fill gaps between the resin particles.Type: GrantFiled: May 19, 2010Date of Patent: October 30, 2012Assignee: Sharp Kabushiki KaishaInventor: Yui Kawano
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Patent number: 8298742Abstract: In a method for coating electrophotographic carrier core surfaces with a resin composition by rotating a rotator having a plurality of agitating blades on its surface in a casing; a coating treatment material that is introduced to a space defined between the rotator and the casing is in a packing of from 50% to 98% by volume; at the time of coating treatment, the electrophotographic carrier core surfaces are coat-treated with the resin composition while being put forward and put backward; and the electrophotographic carrier cores and the resin composition are, at the time of coating treatment, temperature-controlled at a specific temperature T (° C.) or below. This method enables the electrophotographic carrier core surfaces to be more uniformly coated with a coating resin.Type: GrantFiled: December 18, 2008Date of Patent: October 30, 2012Assignee: Canon Kabushiki KaishaInventors: Naoki Okamoto, Yoshinobu Baba, Koh Ishigami, Tomoko Endo
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Patent number: 8293445Abstract: An electrostatic image developing carrier includes a ferrite particle that contains magnesium element in an amount of about 3.0 wt % or more and about 10.0 wt % or less and manganese element in an amount of about 0.2 wt % or more and less than about 1.0 wt %; and a resin layer that covers the ferrite particle.Type: GrantFiled: September 9, 2009Date of Patent: October 23, 2012Assignee: Fuji Xerox, Co., Ltd.Inventors: Yosuke Tsurumi, Rieko Kataoka
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Patent number: 8293446Abstract: A resin-coated carrier is provided. A resin-coated carrier includes a carrier core and a resin coating layer formed on a surface of the carrier core. The carrier core is composed of a porous material having surface fine pores formed on a surface thereof, and has an apparent density of 1.6 to 2.0 g/cm3. The resin coating layer contains cross-linked fine resin particles. Additionally, the resin-coated carrier is configured such that a volume average particle size of the cross-linked fine resin particles contained in the resin coating layer and an area average diameter of the surface fine pores satisfy a predetermined relational expression.Type: GrantFiled: April 28, 2010Date of Patent: October 23, 2012Assignee: Sharp Kabushiki KaishaInventors: Osamu Wada, Takanori Kamoto, Nobuyuki Yoshioka, Ayae Nagaoka, Tadashi Iwamatsu
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Patent number: 8263302Abstract: A carrier for electrophotographic developer, including a core material; and a layer comprising a binder resin, located overlying the core material, wherein the binder resin includes a segment including one or more polymerizable vinyl monomers as a structural unit; and another segment including a partial cleavage structure of polyhedral oligomeric silsesquioxane and/or another partial cleavage structure of polyhedral oligomeric silsesquioxane as a structural unit.Type: GrantFiled: September 8, 2009Date of Patent: September 11, 2012Assignee: Ricoh Company, Ltd.Inventors: Yoshihiro Moriya, Akihiro Kotsugai, Toyoshi Sawada, Ryota Inoue, Akiyoshi Sabu, Shingo Sakashita
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Patent number: 8257896Abstract: A carrier which is capable of avoiding excess blocking of the carrier particles at the time of forming a covering layer and is excellent in durability, a developer containing the carrier, and a developer container containing the developer, as well as an image forming method and a process cartridge which use the developer are provided. A carrier including at least a core material particle and a covering layer, a surface of the core material particle being covered with the covering layer, wherein the covering layer contains a condensate which is obtained by condensation of a silicone resin having at least one of a silanol group and a functional group which can be converted to the silanol group by hydrolysis, using a titanium diisopropoxy bis(ethylaceto-acetate) catalyst.Type: GrantFiled: March 10, 2010Date of Patent: September 4, 2012Assignee: Ricoh Company, Ltd.Inventors: Minoru Masuda, Kimitoshi Yamaguchi, Yutaka Takahashi, Koichi Sakata, Hitoshi Iwatsuki, Toyoaki Tano
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Patent number: 8247150Abstract: A carrier for developing an electrostatic latent image which includes a core material and a resin coating layer provided on the core material. The resin coating layer includes a resin and a particulate tin oxide, and the surface of the particulate tin oxide is coated with carbon.Type: GrantFiled: September 17, 2009Date of Patent: August 21, 2012Assignee: Ricoh Company, Ltd.Inventors: Hitoshi Iwatsuki, Kimitoshi Yamaguchi, Minoru Masuda, Yutaka Takahashi, Koichi Sakata
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Patent number: 8211610Abstract: The carrier includes a particulate core material having magnetism; and a resin layer located on the surface of the particulate core material. The resin layer is prepared by forming a layer including a copolymer, which includes a unit (A) having a specific acrylic siloxane structure, a unit (B) having a specific acrylic silicone structure having a crosslinking ability, and a unit (C) having a specific acrylic structure in a specific ratio, on the particulate core material, and then subjecting the layer to a heat treatment to crosslink the layer.Type: GrantFiled: March 1, 2010Date of Patent: July 3, 2012Assignee: Ricoh Company LimitedInventors: Kimitoshi Yamaguchi, Minoru Masuda, Yutaka Takahashi, Koichi Sakata, Hitoshi Iwatsuki, Toyoaki Tano
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Patent number: 8187781Abstract: Employed are a resin-filled ferrite carrier for an electrophotographic developer filled with a resin in voids of a porous ferrite core material, wherein the resin filled in the voids is a silicone resin which has a softening point of 40° C. or above and is cured at or above such softening point, and the filled amount is 7 to 30 parts by weight based on 100 parts by weight of the core material, a method for producing thereof band an electrophotographic developer using this ferrite carrier.Type: GrantFiled: March 4, 2008Date of Patent: May 29, 2012Assignee: Powdertech Co., Ltd.Inventors: Hiromichi Kobayashi, Takao Sugiura
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Patent number: 8142972Abstract: Provided is a developer for replenishment capable of forming a high-quality image even upon duration. The developer for replenishment includes at least a toner and a magnetic carrier, and in the developer for replenishment, 1 part by mass of the magnetic carrier is blended with 2 to 50 parts by mass of the toner, and the magnetic carrier contains a ferrite core and a resin component, has a true specific gravity of 2.5 to 4.2 g/cm3, has a 50% particle diameter on a volume basis (D50) of 15 to 70 ?m, and has an average circularity of 0.850 to 0.950, the average circularity having a coefficient of variation of 1.0 to 10.0%.Type: GrantFiled: December 5, 2006Date of Patent: March 27, 2012Assignee: Canon Kabushiki KaishaInventors: Yojiro Hotta, Kazuo Terauchi, Kunihiko Nakamura, Hiroyuki Fujikawa, Yoshinobu Baba, Takayuki Itakura, Hirohide Tanikawa
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Patent number: 8101330Abstract: A two component developer comprising a toner and a carrier, wherein the toner includes: colored particles; and external additive particles comprising a complex oxide incorporating silicon atoms and at least one of titanium atoms and aluminum atoms, and a surface existing ratio of the silicon atoms (R2) in a surface of the external additive particles being larger than an average existing ratio of the silicon atoms (R1) in an entirety of the external additive particles, and carrier particles comprise magnetic material powder dispersed in a phenol-formaldehyde resin, and have an average of the shape coefficient SF-1 of 1.0 to 12 and an average of the shape coefficient SF-2 of 1.1 to 2.5, and a volume based median diameter of from 10 to 100 ?m.Type: GrantFiled: March 4, 2009Date of Patent: January 24, 2012Assignee: Konica Minolta Business Technologies, Inc.Inventors: Masahiro Anno, Masahiko Nakamura, Tsuyoshi Uchida, Kenichi Onaka, Junya Onishi, Naoya Tonegawa
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Patent number: 8080357Abstract: When being blended particularly in a color toner, a barium titanate external additive for toner enhances the toner fluidity, electrical properties, and other relevant performance; concurrently achieves high image density and reduced background fog in a color printer using the toner; and further retains high image quality even under a high-temperature high-humidity environment and a low-temperature low-humidity environment. An industrially advantageous producing method of the barium titanate external additive for toner is also provided. The external additive for toner of the present invention includes spherical barium titanate having undergone coating treatment with a hydrophobicizing agent.Type: GrantFiled: January 25, 2007Date of Patent: December 20, 2011Assignee: Nippon Chemical Industrial Co., Ltd.Inventors: Kazuo Ochiai, Shinji Tanabe, Naoaki Narishige
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Patent number: 8043781Abstract: A toner comprising a small-particle diameter external additive having a number average particle diameter of 7 to 20 nm, a large-particle diameter external additive having a number average particle diameter of 40 to 80 nm and a toner particle having a volume average particle diameter of 4 to 7 ?m, wherein the large-particle diameter external additive is stuck to the surface of the toner particles in a semi-embedded state and has a rate of liberation of 0.1% by weight or less from the surface of the toner particle.Type: GrantFiled: August 1, 2008Date of Patent: October 25, 2011Assignee: Sharp Kabushiki KaishaInventors: Tatsuo Imafuku, Takahiro Bito, Takeshi Satoh
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Patent number: 8039190Abstract: A carrier core material for an electrophotographic developer including Li ferrite, maghemite, and Fe3O4, wherein a part thereof is substituted with Mn, Li content is 1 to 2.5% by weight, Mn content is 2 to 7.5% by weight, and silicon content is 25 to 10,000 ppm, the following equation (1) is satisfied when respective integrated strengths of spinel crystal structure (110), (210), (211), and (311) faces in X-ray diffraction are respectively I110, I210, I211, and I311, a resistivity R50 of 50 V across a 6.5 mm gap is 5×107 to 7×108?, and a resistivity R1000 of 1,000 V across a 6.5 mm gap is 1×107 to 8×108?. 2<100×(I110+I210+I211)/I311<14??(1).Type: GrantFiled: March 6, 2009Date of Patent: October 18, 2011Assignees: Mitsui Mining & Smelting Co., Ltd., Powdertech Co., Ltd.Inventors: Yasunori Tabira, Koji Aga, Tomoyuki Suwa
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Patent number: 8026032Abstract: A carrier for use in an image forming apparatus in which a toner and a carrier are fed to an image developer thereof and an extra developer including the toner and the carrier in the image developer is discharged therefrom, wherein at least one of the carrier fed to the image developer and a carrier readily contained therein includes a core material; and a coated film coating the core material, and wherein the coated film includes a binder resin and a particulate material having a ratio of an average particle diameter thereof to an average thickness of the coated film of from 0.01 to 1, and includes concavities and convexities having an average difference of elevation of from 0.02 to 3.0 ?m.Type: GrantFiled: October 11, 2007Date of Patent: September 27, 2011Assignee: Ricoh Company, Ltd.Inventors: Hitoshi Iwatsuki, Tomio Kondou, Shinichiro Yagi, Masashi Nagayama
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Patent number: 7939233Abstract: A magnetic carrier and a two-component developer are provided which have remedied blank areas, fog after leaving, carrier sticking during running, and image density variations before and after running. The magnetic carrier has magnetic carrier particles having at least porous magnetic core particles and a resin. The magnetic carrier particles satisfying the specific conditions (a), (b) and (c) where, in a reflected electron image of cross sections of the magnetic carrier particles as photographed with a scanning electron microscope, straight lines that divide a cross section of a magnetic carrier particle into 72 at intervals of 5° are drawn from a reference point of the cross section thereof toward the surface of the magnetic carrier particle; the magnetic carrier particles being contained in an amount of 60% by number or more.Type: GrantFiled: January 21, 2010Date of Patent: May 10, 2011Assignee: Canon Kabushiki KaishaInventors: Chika Inoue, Hiroyuki Fujikawa, Koh Ishigami, Kunihiko Nakamura, Nozomu Komatsu, Tomoko Endo, Yoshinobu Baba, Takayuki Itakura
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Publication number: 20110097662Abstract: The present disclosure provides carriers for use with toner compositions. In embodiments, a carrier may include a core, having a dry powder polymer coating. The polymer coating possesses a carbon to oxygen from about 3:1 to about 8:1. In embodiments, the coating may also include a colorant, such as carbon black. Processes for coating such carriers with the dry powder polymer coatings are also provided.Type: ApplicationFiled: October 22, 2009Publication date: April 28, 2011Applicant: XEROX CORPORATIONInventors: Daryl W. Vanbesien, Michael S. Hawkins, Suxia Yang, Richard P.N. Veregin, Karen Ann Moffat
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Patent number: 7927775Abstract: Provided is a magnetic carrier giving a high quality image free of density variation without the occurrence of fogging or carrier adhesion and having excellent dot reproducibility even during long-term use. The magnetic carrier has magnetic carrier particles produced by filling pores of porous magnetic core particles with a resin. The magnetic carrier contains 80% by number or more of the magnetic carrier particles satisfying the specific conditions (a) and (b) when 18 straight lines passing through a reference point of a cross section of the magnetic carrier particle are drawn at intervals of 10° in a reflected electron image of the cross section of the magnetic carrier particle photographed by a scanning electron microscope.Type: GrantFiled: January 21, 2010Date of Patent: April 19, 2011Assignee: Canon Kabushiki KaishaInventors: Nozomu Komatsu, Koh Ishigami, Hiroyuki Fujikawa, Kunihiko Nakamura, Chika Inoue, Yoshinobu Baba, Takayuki Itakura, Tomoko Endo
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Publication number: 20110086307Abstract: A carrier, including a magnetic particulate core material and a resin layer on the core material, wherein the resin layer includes a resin obtained by heat treatment of a copolymer including a site derived from a monomer component having the following formula (1) and a site derived from a monomer component having the following formula (2), and includes a cross-linked material obtained by hydrolysis of the copolymer to produce a silanol group and condensation using an organotitanium compound: wherein R1 represents a hydrogen atom or a methyl group; m represents an alkylene group having 1 to 8 carbon atoms; R2 represents an alkyl group having 1 to 4 carbon atoms; R3 represents an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms; X represents 10 to 90 mol %; and Y represents 10 to 90 mol %.Type: ApplicationFiled: October 1, 2010Publication date: April 14, 2011Inventors: Hisashi NAKAJIMA, Kimitoshi Yamaguchi, Minoru Masuda, Yutaka Takahashi, Koichi Sakata, Hitoshi Iwatsuki, Saori Yamada, Toyoaki Tano
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Publication number: 20110020747Abstract: An electrophotographic carrier includes a magnetic core material and a resin layer that coats the magnetic core material, the resin layer comprising a resistance control agent and a polymer including a repeating unit derived from an alicyclic group-containing methacrylic ester, the resin layer including a monomer as a base material of the repeating unit in the polymer in an amount of from about 0.5% by weight to about 3.0% by weight relative to the total amount of the resin layer.Type: ApplicationFiled: March 18, 2010Publication date: January 27, 2011Applicant: FUJI XEROX CO., LTD.Inventors: Fusako Kiyono, Takeshi Shoji, Yosuke Tsurumi, Akihiro Iizuka
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Publication number: 20110013948Abstract: Objects of the present invention are to provide a carrier core material for an electrophotographic developer having a true spherical shape and excellent strength, and a controllable true density and/or apparent density, and a method for manufacturing the carrier core material, a carrier and a method for manufacturing the carrier, and an electrophotographic developer using the carrier. In order to achieve the objects, there are employed a carrier core material for an electrophotographic developer, containing 3 to 100% by number of hollow particles having an iron content of 36 to 78% by weight, and a carrier for an electrophotographic developer, obtained by coating a resin on a surface of the carrier core material, and methods for manufacturing these, and an electrophotographic developer using the carrier.Type: ApplicationFiled: February 27, 2009Publication date: January 20, 2011Applicant: POWDERTECH CO., LTD.Inventors: Koji Aga, Issei Shinmura, Tetsuya Igarashi
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Patent number: 7862977Abstract: A method to form an image using a trickle developing system, wherein (a) the toner comprises colorant particles with a volume median diameter of 3 to 8 ?m having first inorganic particles on surfaces of the colorant particles to form toner particles; (b) the carrier comprises magnetic particles with a weight average particle diameter (D4) of 20 to 40 ?m having second inorganic particles on surfaces of the magnetic particles to form carrier particles; and (c) an area ratio of element (A) based on a total area of surfaces of the carrier particles is 0.5 to 3.0 area % determined by using an X-ray analysis, provided that element (A) represents one or more elements commonly contained in the first inorganic particles and in the second inorganic particles.Type: GrantFiled: April 3, 2007Date of Patent: January 4, 2011Assignee: Konica Minolta Business Technologies, Inc.Inventors: Makoto Kobayashi, Yoshiyasu Matsumoto
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Publication number: 20100310982Abstract: A method for producing a carrier, including a step of periodically forming and discharging liquid droplets of a carrier core composition liquid from a plurality of nozzles formed in a thin film, using a liquid droplet forming unit having the thin film and a ring-shaped vibration generating unit disposed in a deformable area of the thin film so as to be along a circumference of the area and to vibrate the thin film, a step of forming carrier core particles by solidifying the discharged liquid droplets, and a step of coating the carrier core particles with a resin layer.Type: ApplicationFiled: December 18, 2008Publication date: December 9, 2010Inventors: Shinji Ohtani, Ryota Inoue, Yoshihiro Norikane
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Patent number: 7824833Abstract: A spherical resin-coated ferrite carrier for an electrophotographic developer which can maintain a stable resistance and chargeability, a favorable charge rising property because of an excellent fluidity, and has a suitable durability, its production method which is excellent in economic efficiency and production stability, and an electrophotographic developer using the resin-coated ferrite carrier, are provided. A resin-coated ferrite carrier for an electrophotographic developer which is a spherical resin-coated ferrite carrier, wherein a carrier core material thereof has an irregular surface to improve the adhesive strength to a resin coat, and wherein the irregularity of the surface takes a finely streaked wrinkle pattern, its production method, and an electrophotographic developer using the resin-coated ferrite carrier, are employed.Type: GrantFiled: November 30, 2006Date of Patent: November 2, 2010Assignee: Powdertech Co., Ltd.Inventors: Kanao Kayamoto, Issei Shinmura, Toshio Honjo
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Publication number: 20100248112Abstract: A two-component developer including a yellow toner and a carrier, the yellow toner including at least one of C. I. Pigment Yellow 155 or C. I. Pigment Yellow 185, and an azo pigment, the carrier including a first resin, magnetic particles dispersed in the first resin, and elements of Cu, Zn, Ni and Mn each in an amount of from 0 to about 2,000 ppm.Type: ApplicationFiled: September 28, 2009Publication date: September 30, 2010Applicant: FUJI XEROX CO., LTD.Inventors: Norihito FUKUSHIMA, Manabu SERIZAWA, Katsuyuki KITAJIMA
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Patent number: 7769327Abstract: A developing device includes a developing roller and a blade. The developing roller includes: a developing sleeve which rotates while holding two-component developer composed of toner and magnetic carrier on the outer surface having a plurality of grooves extending in parallel to an axis of the rotation; and a magnetic member, provided inside the developing sleeve in such a manner as to be unrotatable, for attracting the two-component developer onto the outer surface of the developing sleeve. The blade is provided outside the rotating sleeve with a gap from the outer surface of the developing sleeve for scraping off a part of the two-component developer on the outer surface of the developing sleeve. Also, the magnetic member includes a magnet for controlling magnetic flux density in the gap to range from 70 mT to 150 mT. This allows preventing image degradation caused by generation of development memory.Type: GrantFiled: July 1, 2008Date of Patent: August 3, 2010Assignee: Sharp Kabushiki KaishaInventors: Kiyofumi Morimoto, Kohichi Takenouchi, Mitsuru Tokuyama, Hiroo Naoi, Kazuma Hinoue
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Patent number: 7754408Abstract: A carrier includes at least one magnetic material and a conductive material. The conductive material is at least one carbon nanotube. A developer includes a toner and the carrier.Type: GrantFiled: September 29, 2005Date of Patent: July 13, 2010Assignee: Xerox CorporationInventors: Samir Kumar, Dan A. Hays
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Publication number: 20100119968Abstract: Provided is a magnetic carrier giving a high quality image free of density variation without the occurrence of fogging or carrier adhesion and having excellent dot reproducibility even during long-term use. The magnetic carrier has magnetic carrier particles produced by filling pores of porous magnetic core particles with a resin. The magnetic carrier contains 80% by number or more of the magnetic carrier particles satisfying the specific conditions (a) and (b) when 18 straight lines passing through a reference point of a cross section of the magnetic carrier particle are drawn at intervals of 10° in a reflected electron image of the cross section of the magnetic carrier particle photographed by a scanning electron microscope.Type: ApplicationFiled: January 21, 2010Publication date: May 13, 2010Applicant: CANON KABUSHIKI KAISHAInventors: Nozomu Komatsu, Koh Ishigami, Hiroyuki Fujikawa, Kunihiko Nakamura, Chika Inoue, Yoshinobu Baba, Takayuki Itakura, Tomoko Endo
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Publication number: 20100086869Abstract: To provide a carrier for two-component electrophotographic developer not only having excellent fluidity but also having proper surface irregularities necessary for imparting electric charge, without generating cracks/chipping of particles even under an influence of stirring stress over a long period of time. A particle surface has raised parts of striped pattern extending almost continuously in a plurality of directions while being superposed on one another, with a surface formed with raised parts of striped pattern occupying 80% or more of the whole surface of a particle. Depths of grooves between the adjacent raised parts are 0.05 ?m or more and 0.2 ?m or less, average surface roughness Ra is 0.1 ?m or more and 0.3 ?m or less, roundness is 0.90 or more, and average particle size is 151 ?m or more and 100 ?m or less, and a carrier core material thus constituted is coated with resin. Thus, the carrier for two-component electrophotographic developer is prepared.Type: ApplicationFiled: March 26, 2008Publication date: April 8, 2010Applicants: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.Inventors: Tomoya Yamada, Isao Fujita, Yoshiaki Aiki
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Publication number: 20100075244Abstract: To provide a carrier for electrophotographic developer, capable of realizing a high image quality and full colorization and reducing carrier scattering, and a manufacturing method of the same, and an electrophotographic developer containing the carrier. A carrier core material for electrophotographic developer, with a general formula expressed by MgxMn(1-x)FeyO4 (where 0<x<1, and 1.6?y?2.4), wherein a half-value width B of a peak having a maximum intensity in a powder XRD pattern satisfies B?0.180 (degree), is manufactured and from this carrier core material for electrophotographic developer, the carrier for electrophotographic developer and the electrophotographic developer are manufactured.Type: ApplicationFiled: April 9, 2008Publication date: March 25, 2010Applicants: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.Inventors: Tomoya Yamada, Takashi Fujiwara, Ryusuke Nakao, Yukihiro Matuda, Tomokazu Mouri
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Publication number: 20100068645Abstract: A carrier for developing an electrostatic latent image which includes a core material and a resin coating layer provided on the core material. The resin coating layer includes a resin and a particulate tin oxide, and the surface of the particulate tin oxide is coated with carbon.Type: ApplicationFiled: September 17, 2009Publication date: March 18, 2010Inventors: Hitoshi Iwatsuki, Kimitoshi Yamaguchi, Minoru Masuda, Yutaka Takahashi, Koichi Sakata
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Publication number: 20100035174Abstract: To provide a carrier for an electrophotographic developer in which high image quality and full colorization are possible while carrier scattering is reduced, and a method for producing the carrier, and an electrophotographic developer including the carrier. A carrier core material for an electrophotographic developer is produced so that the half-value width B of a peak having a maximum intensity in an XRD pattern satisfies B?0.160 (degree). A carrier for an electrophotographic developer and an electrophotographic developer are produced from the carrier core material for an electrophotographic developer.Type: ApplicationFiled: March 21, 2008Publication date: February 11, 2010Applicants: Dowa Electronics Materials Co., Ltd., Dowa IP Creation Co., Ltd.Inventors: Tomoya Yamada, Takashi Fujiwara, Ryusuke Nakao, Yukihiro Matuda, Tomokazu Mouri
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Publication number: 20100028796Abstract: A magnetic carrier and two-component developer are provided alleviating coarse images, fogging when printing is done after a copier body is left standing for one week in a high temperature and high humidity environment and carrier adhesion after extensive operation in a low image ratio. The magnetic carrier includes magnetic carrier particles including porous magnetic core particles and a resin, wherein in a mercury intrusion method applied to the porous magnetic core particles, a pore diameter in which a differential pore volume in the specific pore diameter range becomes maximum is in a specific range, and when the maximum value of a differential pore volume in the specific pore diameter range is defined as P1 and the maximum value of a differential pore volume in the specific pore diameter range is defined as P2, P1 is in a specific range and the ratio P2/P1 is in a specific range.Type: ApplicationFiled: August 4, 2009Publication date: February 4, 2010Applicant: CANON KABUSHIKI KAISHAInventors: Kunihiko Nakamura, Hiroyuki Fujikawa, Koh Ishigami, Nozomu Komatsu, Chika Inoue, Tomoko Endo, Yoshinobu Baba, Takayuki Itakura
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Patent number: 7632620Abstract: A carrier comprised of a core, and thereover a polymer coating containing a first polymer and a silicone resin, and which resin possesses an average diameter of from about 300 to about 3,000 nanometers.Type: GrantFiled: January 28, 2005Date of Patent: December 15, 2009Assignee: Xerox CorporationInventors: Brian S. Giannetto, Thomas J. Budny, Brian E. Moore, Zhaoyi M. Masucci, Samir Kumar, Bernard A. Kelly, Lloyd D. Spencer
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Publication number: 20090291274Abstract: The use of electrographic printing to prepare prints which have a desired tactile feel or raised information in a controlled manner by utilizing a developer having toner particle size larger than 50 microns volume average diameter and carrier particles larger than the toner particle size such that the volume average distribution overlap between the toner distribution curve and carrier particle distribution curve is less than 35% and the carrier and toner particles have a volume average diameter size differential equal to or greater than 5 microns or the ratio of carrier-to-toner volume average diameter exceeds 1.25.Type: ApplicationFiled: May 21, 2008Publication date: November 26, 2009Inventors: Dinesh Tyagi, Patrick M. Lambert, Mark C. Zaretsky, Thomas N. Tombs
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Publication number: 20090258311Abstract: The present invention provides a carrier core material for use in the production of an electrophotographic developer which, even when applied, for example, to MFPs (multifunction printers), can realize stable, high-quality and high-speed development, and has a prolonged replacing life of magnetic carriers, and a method of manufacturing the same, a magnetic carrier including the carrier core material, and an electrophotographic developer manufactured from the magnetic carrier. An electrophotographic development carrier is prepared by adding resin particles, a binder, a dispersant, a wetting agent, and water to a raw material powder, wet pulverizing the mixture, drying the pulverized product to give granulated powder, calcinatng the granulated powder, and then sintering the granulated powder to prepare a carrier core material having an internally hollow structure, and coating the carrier core material with a resin.Type: ApplicationFiled: September 25, 2006Publication date: October 15, 2009Inventors: Ryusuke Nakao, Takeshi Kawauchi
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Patent number: 7598011Abstract: It is contemplated to provide irregular shaped ferrite carrier which has a lower resistance, a high specific surface area, a low specific gravity and a longer operational life, and an electrophotographic developer comprising the ferrite carrier which prevents the toner scattering, has a high image density, and is responsive to high-speed and color imaging. The irregular shaped ferrite carrier is characterized in that the carrier particles are irregular shaped, and 40 percent by number or more of the particles have a rock candy sugar shape and/or an oyster shell shape, and that the shape factor (SF-1=R2/S×?/4×100, wherein R is a maximum length and S is a projected area.) is 140 to 250, and the distribution width (?) is 60 or less.Type: GrantFiled: February 28, 2006Date of Patent: October 6, 2009Assignee: Powdertech Co., Ltd.Inventors: Hiromichi Kobayashi, Toru Iwata, Toshio Honjo
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Patent number: 7577377Abstract: In a developing device of the present invention, the ratio of the volume of a two-ingredient type developer to the capacity of a space storing the developer is selected to range from 40% to 75%. A carrier, forming part of the developer, is made up of a core and a resinous coating layer formed on the core. The resinous coating layer contains conductive particles each having a tin dioxide layer formed on a core and an indium oxide layer formed on the tin dioxide layer and containing tin dioxide. The conductive particles are provided with an oil absorbing amount ranging from 10 ml/100 g to 300 ml/100 g.Type: GrantFiled: October 25, 2005Date of Patent: August 18, 2009Assignee: Ricoh Company, Ltd.Inventors: Satoru Miyamoto, Makoto Yasuda
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Patent number: 7574164Abstract: An electrophotographic apparatus includes: a photoconductor; and two developing rollers facing the photoconductor. A developer fed out from between the two developing rollers is supplied to the photoconductor by the two developing rollers to form a toner image on the photoconductor. The developer includes a carrier having a volume-average particle size smaller than 70 ?m and a volume resistivity not lower than 106 ?·cm. A volume ratio of the carrier in a facing portion between the photoconductor and the developing rollers is not lower than 30% and not higher than 46%.Type: GrantFiled: September 23, 2005Date of Patent: August 11, 2009Assignee: Ricoh Company Ltd.Inventors: Hisao Okada, Hiroyuki Mabuchi, Teruaki Mitsuya, Tsuneaki Kawanishi, Akio Tsujita
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Publication number: 20090186292Abstract: There is provided a method for producing a carrier, which includes depositing a resin coating layer on the surface of a magnetic material; adding a treatment agent for a conductor precursor to the resin coating layer so as to treat the resin coating layer with the treatment agent; and exposing the treatment agent-added resin coating layer to a conductor precursor in a supercritical or subcritical fluid so as to form a conductor in the resin coating layer.Type: ApplicationFiled: December 31, 2008Publication date: July 23, 2009Inventors: Ryota Inoue, Akihiro Kotsugai, Yoshihiro Moriya, Shingo Sakashita
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Publication number: 20090169263Abstract: Carrier particles for a developer used in an image forming apparatus, in which the carrier particles contain a core material containing magnetic particles, and a coating layer formed on a surface of the core material, and the coating layer contains diamond fine particles or diamond-like carbon exposed on a surface of the coating layer.Type: ApplicationFiled: December 22, 2008Publication date: July 2, 2009Applicants: KABUSHIKI KAISHA TOSHIBA, TOSHIBA TEC KABUSHIKI KAISHAInventors: Takeshi Watanabe, Mitsuaki Kouyama
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Patent number: 7553597Abstract: A carrier core material containing at least one metal oxide (MLO) having a melting point of not higher than 1000° C. and at least one metal oxide (MHO) having a melting point of not lower than 1800° C., wherein the metal (MH) for constituting the metal oxide (MHO) has an electrical resistivity of not less than 10?5 ?·cm. Also disclosed is a two-component developing agent comprising a coated carrier, which comprises the carrier core material coated with a resin, and toner particles. Further disclosed is an image forming method comprising developing an electrostatic latent image formed on a photosensitive member with the two-component developing agent using an alternating electric field. The carrier core material and the coated carrier have high magnetization and are free from occurrence of leakage of electric charge over a wide range of electric field from low electric field to high electric field. According to the two-component developing agent, an excellent image can be formed.Type: GrantFiled: February 6, 2004Date of Patent: June 30, 2009Assignee: Powdertech Co., Ltd.Inventors: Hiromichi Kobayashi, Issei Shinmura, Tsuyoshi Itagoshi, Yuji Sato
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Publication number: 20090029281Abstract: To provide a two-component developer and an image forming device which are excellent in stability of image density in formed images even when image formation is continued for a long time, by controlling non-electrostatic adhesion force between toner particle and a carrier or developing roll and maintaining the charge property of toner particle effectively. A two-component developer in which the surface of a toner particle and the surface of a carrier are each covered with a fluorine compound, wherein a ratio represented by (A2/A1) is adjusted to a value within a range of from 0.1 to 0.5 where the coverage with the fluorine compound on the surface of the toner particle is A1 and the coverage with the fluorine compound on the surface of the carrier is (A2).Type: ApplicationFiled: June 30, 2008Publication date: January 29, 2009Applicant: KYOCERA MITA CORPORATIONInventor: Seiji Kikushima
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Patent number: 7482104Abstract: An image forming method, includes: forming a latent electrostatic image on a latent electrostatic image carrier; developing the latent electrostatic image with a toner to thereby form a visible image; transferring the visible image to a recording medium; and fixing the image transferred to the recording medium. The latent electrostatic image carrier includes: a support, a photoconductive layer on the support, and a surface protective layer on the support. The surface protective layer includes a reactant made by cross-linking the following: an electric charge transporting material which comprises a reactive functional group, a cross-linking resin, and a fluorine surfactant. The toner comprises an inorganic fine particle which defines an effective inorganic fine particle amount in a range of 0.8% by mass to 3.Type: GrantFiled: April 16, 2008Date of Patent: January 27, 2009Assignee: Ricoh Company, Ltd.Inventors: Maiko Kondo, Hidetoshi Kami, Naohiro Toda, Ryoichi Kitajima, Hiroshi Nagame, Narihito Kojima, Yoshiaki Kawasaki
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Patent number: 7459254Abstract: Toner includes aggregated and associated particles formed by mixing in an aqueous medium at least a resin particle dispersion in which resin particles are dispersed, a colorant particle dispersion in which colorant particles are dispersed, and a wax particle dispersion in which wax particles are dispersed and heat-treating the mixed dispersion for aggregation. The aggregated and associated particles include first particles having a capsule structure in which aggregated wax with an average particle size of greater than 1 ?m is incorporated into the resin, and second particles formed of the resin and the wax in a mixed and dispersed state. The toner can achieve oilless fixing that prevents offset without using oil while maintaining high OHP transmittance and also can eliminate spent of the toner components on a carrier to make the life longer.Type: GrantFiled: November 2, 2004Date of Patent: December 2, 2008Assignee: Panasonic CorporationInventors: Yasuhito Yuasa, Mamoru Soga, Hidekazu Arase
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Patent number: 7457571Abstract: An image forming apparatus and process cartridge which uses a two-component developer comprising a toner and a carrier. By using toner and carrier having a small-particle size, deterioration of the toner fluidity over time can be avoided, and further by maintaining stable toner charge even in a low-humidity environment, stable high-quality image formation can be achieved. The occurrence of adherence of carrier to the solid portions of the toner image is reduced in addition to the occurrence of adherence of carrier to the edge portions, and image abnormalities, toner scattering and the like are prevented.Type: GrantFiled: September 28, 2005Date of Patent: November 25, 2008Assignee: Ricoh Company, Ltd.Inventor: Akira Azami