Patents by Inventor Hiromitsu Misawa
Hiromitsu Misawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9448500Abstract: The present invention provides magnetic iron oxide particles having a high bonding property to a resin as well as a magnetic carrier for electrophotographic developers which is improved in durability by enhancing adhesion between a magnetic carrier core material and a coating resin. The magnetic iron oxide particles of the present invention are magnetic iron oxide particles having an average particle diameter of 0.5 to 30 ?m onto which a plurality of granules are bonded, and the magnetic carrier for electrophotographic developers according to the present invention is a magnetic carrier for electrophotographic developers which comprises spherical magnetic composite particles produced by dispersing magnetic iron oxide particles in a binder resin in which the magnetic iron oxide particles comprise at least the above magnetic iron oxide particles having an average particle diameter of 0.5 to 30 ?m onto which the plurality of granules are bonded.Type: GrantFiled: March 29, 2012Date of Patent: September 20, 2016Assignee: TODA KOGYO CORPORATIONInventors: Shigenori Harada, Shinji Uemoto, Hiromitsu Misawa, Eiichi Kurita, Koso Aoki
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Patent number: 9285698Abstract: Black magnetic iron oxide particles having an average particle diameter of 0.05 to 2.0 ?m and an electric resistance value at an applied voltage of 100 V of not less than 1×108 ?·cm. Also a magnetic carrier for electrophotographic developer having spherical magnetic composite particles obtained by dispersing black magnetic iron oxide particles in a binder resin. The magnetic carrier has an electric resistance value R100 at an applied voltage of 100 V of 1×108 to 1×1014 ?·cm, and an electric resistance value R300 at an applied voltage of 300 V which satisfies the relationship represented by the formula: 0.1?R300/R100?1.Type: GrantFiled: June 15, 2009Date of Patent: March 15, 2016Assignee: TODA KOGYO CORPORATIONInventors: Shinji Uemoto, Hiromitsu Misawa, Ryo Iwai, Naoki Uchida, Koso Aoki, Kazuya Fujita, Kaori Kinoshita, Kazushi Takama, Eiichi Kurita
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Patent number: 8852840Abstract: The present invention relates to magnetic composite particles comprising at least magnetic fine particles and a bio-based polymer, wherein the magnetic composite particles have an average particle diameter of 10 to 100 ?m, and a content of the magnetic fine particles in the magnetic composite particles is 50 to 99.9% by weight; a magnetic carrier; and a developer. The magnetic composite particles, magnetic carrier and developer according to the present invention are effective for reduction of environmental burden such as saving of underground sources and prevention of global warming, have a high safety for human bodies and a high durability, and are capable of forming developed images with a high quality.Type: GrantFiled: March 24, 2010Date of Patent: October 7, 2014Assignee: Toda Kogyo CorporationInventors: Muneyoshi Sakamoto, Eiichi Kurita, Hiromitsu Misawa
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Publication number: 20140051020Abstract: The present invention provides magnetic iron oxide particles having a high bonding property to a resin as well as a magnetic carrier for electrophotographic developers which is improved in durability by enhancing adhesion between a magnetic carrier core material and a coating resin. The magnetic iron oxide particles of the present invention are magnetic iron oxide particles having an average particle diameter of 0.5 to 30 ?m onto which a plurality of granules are bonded, and the magnetic carrier for electrophotographic developers according to the present invention is a magnetic carrier for electrophotographic developers which comprises spherical magnetic composite particles produced by dispersing magnetic iron oxide particles in a binder resin in which the magnetic iron oxide particles comprise at least the above magnetic iron oxide particles having an average particle diameter of 0.5 to 30 ?m onto which the plurality of granules are bonded.Type: ApplicationFiled: March 29, 2012Publication date: February 20, 2014Applicant: TODA KOGYO CORPORATIONInventors: Shigenori Harada, Shinji Uemoto, Hiromitsu Misawa, Eiichi Kurita, Koso Aoki
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Publication number: 20120064448Abstract: The present invention relates to magnetic composite particles comprising at least magnetic fine particles and a bio-based polymer, wherein the magnetic composite particles have an average particle diameter of 10 to 100 ?m, and a content of the magnetic fine particles in the magnetic composite particles is 50 to 99.9% by weight; a magnetic carrier; and a developer. The magnetic composite particles, magnetic carrier and developer according to the present invention are effective for reduction of environmental burden such as saving of underground sources and prevention of global warming, have a high safety for human bodies and a high durability, and are capable of forming developed images with a high quality.Type: ApplicationFiled: March 24, 2010Publication date: March 15, 2012Inventors: Muneyoshi Sakamoto, Eiichi Kurita, Hiromitsu Misawa
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Patent number: 7670676Abstract: There are provided a pharmaceutical raw material capable of exhibiting a uniform functionality and producing magnetic particle-containing drugs for diagnosis and medical treatments with a high reproducibility. The pharmaceutical raw material comprises a monodisperse colloid sterile aqueous solution of magnetic iron oxide fine particles having an average particle diameter of 5 to 30 nm, a saturation magnetization of 50 to 90 Am2/kg and a coercive force of 0.1 to 1.6 kA/m. The pharmaceutical raw material can be produced by forming magnetic iron oxide fine particles in the form of a colloid aqueous solution, purifying the resultant colloid aqueous solution of superparamagnetic iron oxide particles by water-washing and removing water-soluble salts by-produced upon the reaction from the reaction solution by an ordinary method, and replacing a dispersing medium of the purified colloid aqueous solution with ultrapure water.Type: GrantFiled: June 13, 2006Date of Patent: March 2, 2010Assignee: Toda Kogyo CorporationInventors: Nanao Horiishi, Toshiyuki Hakata, Hirofumi Kawasaki, Shinji Uemoto, Hiromitsu Misawa, Seiichi Takahashi
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Publication number: 20090311617Abstract: The present invention relates to black magnetic iron oxide particles having an average particle diameter of 0.05 to 2.0 ?m and an electric resistance value at an applied voltage of 100 V of not less than 1×108 ?·m; and a magnetic carrier for electrophotographic developer comprising spherical magnetic composite particles obtained by dispersing black magnetic iron oxide particles in a binder resin, wherein the magnetic carrier has an electric resistance value R100 at an applied voltage of 100 V of 1×108 to 1×1014 ?·m, and an electric resistance value R300 at an applied voltage of 300 V which satisfies the relationship represented by the formula: 0.1?R300/R100?1.Type: ApplicationFiled: June 15, 2009Publication date: December 17, 2009Applicant: TODA KOGYO CORPORATIONInventors: Shinji Uemoto, Hiromitsu Misawa, Ryo Iwai, Naoki Uchida, Koso Aoki, Kazuya Fujita, Kaori Kinoshita, Kazushi Takama, Eiichi Kurita
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Patent number: 7597958Abstract: The present invention relates to a black magnetic iron oxide particles each having a polyhedral shape wherein when a percentage of dissolution of iron element based on a total amount of iron element contained in the black magnetic iron oxide particles is 50%, a percentage of dissolution of sulfur element based on a total amount of sulfur element contained in the black magnetic iron oxide particles is less than 40%.Type: GrantFiled: February 20, 2008Date of Patent: October 6, 2009Assignee: Toda Kogyo CorporationInventors: Shinji Uemoto, Naoki Uchida, Mamoru Kamigaki, Ryo Iwai, Hiromitsu Misawa, Koso Aoki
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Patent number: 7572505Abstract: The present invention relates to black magnetic iron oxide particles comprising core particles and a surface layer formed on a surface of the respective core particles which is made of a compound of at least one alkali earth metal element selected from the group consisting of Mg, Ca, Sr and Ba and an aluminum element, in which a content of the at least one alkali earth metal element present in the surface layer is from 100 ppm to 1000 ppm on the basis of a whole weight of the black magnetic iron oxide particles; a content of the aluminum element present in the surface layer is from 1000 ppm to 20000 ppm on the basis of a whole weight of the black magnetic iron oxide particles; a ratio [A/B] of the content [A (ppm)] of the aluminum element to the content [B (ppm)] of the at least one alkali earth metal element present in the surface layer is from 1 to 100; and a molded product comprising said black magnetic iron oxide particles has a breakdown voltage of not less than 400 V/cm.Type: GrantFiled: April 19, 2007Date of Patent: August 11, 2009Assignee: Toda Kogyo CorporationInventors: Naoki Uchida, Ryo Iwai, Mamoru Kamigaki, Shinji Uemoto, Koso Aoki, Hiromitsu Misawa
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Publication number: 20080206566Abstract: The present invention relates to a black magnetic iron oxide particles each having a polyhedral shape wherein when a percentage of dissolution of iron element based on a total amount of iron element contained in the black magnetic iron oxide particles is 50%, a percentage of dissolution of sulfur element based on a total amount of sulfur element contained in the black magnetic iron oxide particles is less than 40%.Type: ApplicationFiled: February 20, 2008Publication date: August 28, 2008Applicant: TODA KOGYO CORPORATIONInventors: Shinji Uemoto, Naoki Uchida, Mamoru Kamigaki, Ryo Iwai, Hiromitsu Misawa, Koso Aoki
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Publication number: 20070254157Abstract: The present invention relates to black magnetic iron oxide particles comprising core particles and a surface layer formed on a surface of the respective core particles which is made of a compound of at least one alkali earth metal element selected from the group consisting of Mg, Ca, Sr and Ba and an aluminum element, in which a content of the at least one alkali earth metal element present in the surface layer is from 100 ppm to 1000 ppm on the basis of a whole weight of the black magnetic iron oxide particles; a content of the aluminum element present in the surface layer is from 1000 ppm to 20000 ppm on the basis of a whole weight of the black magnetic iron oxide particles; a ratio [A/B] of the content [A (ppm)] of the aluminum element to the content [B (ppm)] of the at least one alkali earth metal element present in the surface layer is from 1 to 100; and a molded product comprising said black magnetic iron oxide particles has a breakdown voltage of not less than 400 V/cm.Type: ApplicationFiled: April 19, 2007Publication date: November 1, 2007Applicant: TODA KOGYO CORPORATIONInventors: Naoki Uchida, Ryo Iwai, Mamoru Kamigaki, Shinji Uemoto, Koso Aoki, Hiromitsu Misawa
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Publication number: 20060287404Abstract: There are provided a pharmaceutical raw material capable of exhibiting a uniform functionality and producing magnetic particle-containing drugs for diagnosis and medical treatments with a high reproducibility. The pharmaceutical raw material comprises a monodisperse colloid sterile aqueous solution of magnetic iron oxide fine particles having an average particle diameter of 5 to 30 nm, a saturation magnetization of 50 to 90 Am2/kg and a coercive force of 0.1 to 1.6 kA/m. The pharmaceutical raw material can be produced by forming magnetic iron oxide fine particles in the form of a colloid aqueous solution, purifying the resultant colloid aqueous solution of superparamagnetic iron oxide particles by water-washing and removing water-soluble salts by-produced upon the reaction from the reaction solution by an ordinary method, and replacing a dispersing medium of the purified colloid aqueous solution with ultrapure water.Type: ApplicationFiled: June 13, 2006Publication date: December 21, 2006Applicant: TODA KOGYO CORPORATIONInventors: Nanao Horiishi, Toshiyuki Hakata, Hirofumi Kawasaki, Shinji Uemoto, Hiromitsu Misawa, Seiichi Takahashi
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Patent number: 7144626Abstract: There are provided magnetic iron oxide particles having an average particle diameter (Dp50) of primary particles of 0.05 to 0.3 ?m, an average particle diameter (Da50) of secondary particles of 0.055 to 0.9 ?m, and a ratio of the average particle diameter (Da50) of the secondary particles to the average particle diameter (Dp50) of the secondary particles (Da50/Dp50) of 1.1 to 3.0, as well as a magnetic toner containing the magnetic iron oxide particles. The magnetic iron oxide particles of the present invention are in the form of small agglomerated particles and exhibit an excellent dispersibility, and the magnetic toner using the magnetic iron oxide particles is excellent in electrification stability.Type: GrantFiled: April 4, 2005Date of Patent: December 5, 2006Assignee: Toda Kogyo CorporationInventors: Hiroshi Akai, Koso Aoki, Hiromitsu Misawa, Naoki Uchida, Ryo Iwai
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Publication number: 20050227070Abstract: There are provided magnetic iron oxide particles having an average particle diameter (Dp50) of primary particles of 0.05 to 0.3 ?m, an average particle diameter (Da50) of secondary particles of 0.055 to 0.9 ?m, and a ratio of the average particle diameter (Da50) of the secondary particles to the average particle diameter (Dp50) of the secondary particles (Da50/Dp50) of 1.1 to 3.0, as well as a magnetic toner containing the magnetic iron oxide particles. The magnetic iron oxide particles of the present invention are in the form of small agglomerated particles and exhibit an excellent dispersibility, and the magnetic toner using the magnetic iron oxide particles is excellent in electrification stability.Type: ApplicationFiled: April 4, 2005Publication date: October 13, 2005Applicant: TODA KOGYO CORPORATIONInventors: Hiroshi Akai, Koso Aoki, Hiromitsu Misawa, Naoki Uchida, Ryo Iwai
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Patent number: 6780555Abstract: Black magnetic iron oxide particles having an average particle diameter of 0.05 to 1.0 &mgr;m have a three-phase structure comprising: a core portion containing at least one metal element other than Fe selected from the group consisting of Mn, Zn, Cu, Ni, Cr, Cd, Sn, Mg, Ti, Ca and Al in an amount of 0.1 to 10% by weight based on whole Fe contained in the particles; a surface coat portion containing at least one metal element other than Fe selected from the group consisting of Mn, Zn, Cu, Ni, Cr, Cd, Sn, Mg, Ti, Ca and Al in an amount of 0.1 to 10% by weight based on whole Fe contained in the particles; and an intermediate layer disposed between the core portion and the surface coat portion, containing substantially none of the metal elements other than Fe.Type: GrantFiled: January 22, 2002Date of Patent: August 24, 2004Assignee: Toda Kogyo CorporationInventors: Naoki Uchida, Minoru Kouzawa, Hiromitsu Misawa, Koso Aoki, Suehiko Miura
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Patent number: 6596255Abstract: Tin-containing granular magnetic oxide particles comprising spinel-type crystal represented by the formula: Fe3-xSnxO4 wherein x is 0.14 to 0.48, and having a Fe2+ content of 17 to 22% by weight, a lattice constant of 8.41 to 8.49 Å, a magnetization value of 20 to 50 Am2/kg when measured under an applied magnetic field of 79.6 kA/m, and a depth of a groove of not more than 40 &mgr;m at which three or more continuous lines each having a length of not less than 10 mm are developed in a pigment dispersion test using a grind-meter when measured by Hoover's muller method according to JIS K5101 (1991) 9.1. The tin-containing granular magnetic oxide particles of the present invention exhibit a sufficient blackness, a small magnetization value and an excellent dispersibility.Type: GrantFiled: May 22, 2001Date of Patent: July 22, 2003Assignees: National Institute of Advanced Industrial Science and Technology, Toda Kogyo CorporationInventors: Mitsuharu Tabuchi, Tomonari Takeuchi, Hiroyuki Kageyama, Tatsuya Nakamura, Hiromitsu Misawa
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Publication number: 20020168523Abstract: Black magnetic iron oxide particles having an average particle diameter of 0.05 to 1.Type: ApplicationFiled: January 22, 2002Publication date: November 14, 2002Inventors: Naoki Uchida, Minoru Kouzawa, Hiromitsu Misawa, Koso Aoki, Suehiko Miura
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Patent number: 6383637Abstract: Black magnetic iron oxide particles of the present invention having an average particle diameter of 0.1 to 0.3 &mgr;m, comprise: black spinel iron oxide particles as core particles; and a surface coat formed on the surface of each core particle, comprising fine spinel iron oxide particles, the content of FeO in a surface layer having a thickness of from a surface of each black magnetic iron oxide particle to about 3.5% per a radius of each black magnetic iron oxide particle, being 8 to 14% by weight based on the weight of Fe contained in said surface layer. Such black magnetic iron oxide particles not only have a sufficient blackness and excellent electrical properties, flowability and electrification property (charging property), but also exhibit a good compatibility with binder resins such as aromatic vinyl-based resins, acrylic-based resins and copolymer resins thereof, and a good dispersibility in these resins for a magnetic toner.Type: GrantFiled: April 13, 2000Date of Patent: May 7, 2002Assignee: Toda Kogyo CorporationInventors: Hiromitsu Misawa, Koso Aoki, Suehiko Miura, Minoru Kozawa, Naoki Uchida, Nobuya Shimo
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Publication number: 20010055557Abstract: Tin-containing granular magnetic oxide particles comprising spinel-type crystal represented by the formula:Type: ApplicationFiled: May 22, 2001Publication date: December 27, 2001Inventors: Mitsuharu Tabuchi, Tomonari Takeuchi, Hiroyuki Kageyama, Tatsuya Nakamura, Hiromitsu Misawa
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Patent number: 6103437Abstract: Magnetite particles of the present invention have an average particle diameter of 0.05 to 0.50 .mu.m, each of the magnetite particles having a plurality of mountain-shaped protrusions with unsharpened crests on a surface of each magnetite particle, and the number of the mountain-shaped protrusions formed on the surface of each magnetite particle being in the range of 2 to 30 when viewed in projected plan; magnetic iron oxide particles for magnetic toner comprising not less than 60%, in particle number, of the said magnetite particles; and a magnetic toner comprising the said magnetic iron oxide particles and a binder resin. The magnetite particles of the present invention are free from the falling-off from toner particles. The toner particles of the present invention shows a good fluidity and produces visual images having a higher definition upon development of electrostatic latent images.Type: GrantFiled: August 27, 1998Date of Patent: August 15, 2000Assignee: Toda Kogyo CorporationInventors: Minoru Kozawa, Koso Aoki, Hiromitsu Misawa, Sigenori Miyazaki, Naoki Uchida, Kazuo Fujioka