Patents by Inventor Mitsuaki Hirose
Mitsuaki Hirose 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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Publication number: 20230280670Abstract: [Summary] An object of the present invention is to provide a toner that has both low-temperature fixability and heat-resistant storage stability, suppresses contamination of cleaning parts and photoconductors, and has excellent charging stability. [Tasks] A toner includes toner based particles containing a binder resin, a colorant, and a wax; and fine resin particles and an inorganic external additive that are present on a surface of the toner based particles, wherein a coverage of the fine resin particles is in a range from 30% to 70%, and wherein the inorganic external additive covers a surface of oxide of a metal element with hydroxide of a metal element.Type: ApplicationFiled: February 28, 2023Publication date: September 7, 2023Applicant: Ricoh Company, Ltd.Inventors: Tsukiko TAKAHASHI, Mitsuaki Hirose, Yohichi Kitagawa, Suzuka Karato, Hiroshi Yamada
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Publication number: 20230195005Abstract: Provided is a toner including toner particles. Each of the toner particles includes a toner base particle including a binder resin, resin particles covering the toner base particle, and zinc stearate particles serving as an external additive. In each of the toner particles, a coverage rate of the toner base particle with the resin particles is 30% or greater and 70% or less. The zinc stearate particles have a volume average particle diameter of 3 ?m or greater and 20 ?m or less.Type: ApplicationFiled: December 20, 2022Publication date: June 22, 2023Inventors: Taishi YAMASHITA, Yohichi KITAGAWA, Tsukiko TAKAHASHI, Mitsuaki HIROSE, Daisuke INOUE
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Publication number: 20230152724Abstract: A toner includes toner base particles each including a binder resin and a releasing agent, resin particles, and an external additive. Resin particles, from among the resin particles in the toner, and the external additive are deposited on a surface of each of the toner base particles. A standard deviation of a distance between resin particles next to one another on the surface is less than 600 nm, the resin particles next to one another being from among the resin particles deposited on the surface. The external additive includes primary particles each standing alone and non-spherical cohesive particles each including cohered primary particles. A proportion of the primary particles each standing alone per 1,000 particles of the external additive is 30% or less, the particles of the external additive in the per 1,000 particles being the primary particles each standing alone and the cohesive particles.Type: ApplicationFiled: November 9, 2022Publication date: May 18, 2023Inventors: Suzuka KARATO, Mitsuaki HIROSE, Hiroshi YAMADA, Yohichi KITAGAWA, Tsukiko TAKAHASHI
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Publication number: 20230040461Abstract: A toner includes: toner base particles including a binder resin, a colorant, an inorganic filler, and a release agent; and an external additive. An average circularity of the toner is 0.974 or more but 0.985 or less. A surface roughness parameter Sz of a surface of the toner is 200 nm or more but 500 nm or less, the surface roughness parameter Sz being measured with an atomic force microscope (AFM).Type: ApplicationFiled: July 25, 2022Publication date: February 9, 2023Applicant: Ricoh Company, Ltd.Inventors: Daisuke Inoue, Mitsuaki Hirose, Yohichi Kitagawa, Tsukiko Takahashi, Kenji Komito, Akihiko Moki
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Publication number: 20220155699Abstract: A toner is provided. The toner comprises toner particles each comprising a toner base particle and an external additive. The toner base particle comprises a binder resin and a colorant. The toner satisfies the following conditions (a) and (b): (a) an average surface roughness Ra [nm] of the toner particles, detected by a scanning probe microscope analyzer, satisfies the following formula (1): 10<Ra<200??Formula (1); and (b) the external additive comprises coalesced particles being non-spherical secondary particles in which primary particles are coalesced with each other, the coalesced particles having a number average particle diameter of 50 nm or more.Type: ApplicationFiled: October 14, 2021Publication date: May 19, 2022Applicant: Ricoh Company, Ltd.Inventors: Yohichi KITAGAWA, Kenji Komito, Masayuki Ukigaya, Mitsuaki Hirose, Daisuke Inoue
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Publication number: 20220057725Abstract: A toner is provided. The toner comprises toner base particles, resin particles adhered to surfaces of the toner base particles, and an external additive adhered to the surfaces of the toner base particles. The toner base particles each comprising a binder resin, a colorant, and a wax. The toner has a storage elastic modulus G? of 4.0×105 or less at 70° C. An embedment degree of the external additive is from 15% to 40%, as the embedment degree is measured by stirring 10 g of the toner and 20 g of a carrier in a 50-mL vial at 67 Hz for 60 minutes using a rocking mill.Type: ApplicationFiled: August 16, 2021Publication date: February 24, 2022Applicant: Ricoh Company, Ltd.Inventors: Daisuke INOUE, Mitsuaki Hirose, Yohichi Kitagawa, Masayuki Ukigaya, Kenji Komito, Hiroshi Yamada
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Patent number: 11016403Abstract: An electrophotographic photoconductor is provided that includes a conductive substrate, an undercoat layer overlying the conductive substrate, and a photosensitive layer overlying the undercoat layer. The undercoat layer contains zinc oxide particles and a binder resin and has a volume resistivity of 0.03×106 ?·cm or less in an electrical field of 5 V/?m at a temperature of 23 degrees C. and a relative humidity of 55%. The photosensitive layer contains a compound represented by the following general formula (1): where each of R1 to R3 independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms.Type: GrantFiled: January 15, 2020Date of Patent: May 25, 2021Assignee: Ricoh Company, Ltd.Inventors: Hideki Nakamura, Tadayoshi Uchida, Shuya Sugimoto, Mitsuaki Hirose, Noboru Toriu, Kaori Harada
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Publication number: 20200233325Abstract: An electrophotographic photoconductor is provided that includes a conductive substrate, an undercoat layer overlying the conductive substrate, and a photosensitive layer overlying the undercoat layer. The undercoat layer contains zinc oxide particles and a binder resin and has a volume resistivity of 0.03×106 ?·cm or less in an electrical field of 5 V/?m at a temperature of 23 degrees C. and a relative humidity of 55%. The photosensitive layer contains a compound represented by the following general formula (1): where each of R1 to R3 independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms.Type: ApplicationFiled: January 15, 2020Publication date: July 23, 2020Inventors: Hideki Nakamura, Tadayoshi Uchida, Shuya Sugimoto, Mitsuaki Hirose, Noboru Toriu, Kaori Harada
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Patent number: 10466604Abstract: Provided is an electrophotographic photoconductor including: a conductive support; an undercoat layer; and a photoconductive layer, wherein the undercoat layer and the photoconductive layer are provided over the conductive support in the order of reciting, wherein the undercoat layer contains at least metal oxide particles, a binder, and a salicylic acid derivative such as 4-methylsalicylic acid, wherein the metal oxide particles have a volume resistivity of 1×105 ?·cm or higher but 1×108 ?·cm or lower, wherein the undercoat layer has a volume resistivity of 0.001×106 ?·cm or higher but 0.02×106 ?·cm or lower, and wherein the undercoat layer has a thickness of 2 micrometers or greater but 20 micrometers or less.Type: GrantFiled: July 2, 2018Date of Patent: November 5, 2019Assignee: Ricoh Company, Ltd.Inventors: Tetsuya Toshine, Mitsuaki Hirose, Tomoharu Asano
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Publication number: 20190011845Abstract: Provided is an electrophotographic photoconductor including: a conductive support; an undercoat layer; and a photoconductive layer, wherein the undercoat layer and the photoconductive layer are provided over the conductive support in the order of reciting, wherein the undercoat layer contains at least metal oxide particles, a binder, and a salicylic acid derivative such as 4-methylsalicylic acid, wherein the metal oxide particles have a volume resistivity of 1×105 ?·cm or higher but 1×108 ?·cm or lower, wherein the undercoat layer has a volume resistivity of 0.001×106 ?·cm or higher but 0.02×106 ?·cm or lower, and wherein the undercoat layer has a thickness of 2 micrometers or greater but 20 micrometers or less.Type: ApplicationFiled: July 2, 2018Publication date: January 10, 2019Inventors: Tetsuya TOSHINE, Mitsuaki Hirose, Tomoharu Asano
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Patent number: 10073363Abstract: A photoconductor is provided. The photoconductor includes a cylindrical conductive support, a water-repellent resin film, a coating film, and a flange. The cylindrical conductive support has an end part having an inner circumferential surface having a surface roughness Rz of from 3 to 10 ?m. The water-repellent resin film is on the inner circumferential surface of the end part of the cylindrical conductive support. The coating film is on an outer circumferential surface of the cylindrical conductive support. The flange has a cylindrical fitting part having an outer circumferential surface secured to the inner circumferential surface of the end part of the cylindrical conductive support.Type: GrantFiled: January 3, 2017Date of Patent: September 11, 2018Assignee: Ricoh Company, Ltd.Inventors: Mitsuaki Hirose, Daisuke Kubo, Hiroshi Hashiguchi
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Publication number: 20170212435Abstract: A photoconductor is provided. The photoconductor includes a cylindrical conductive support, a water-repellent resin film, a coating film, and a flange. The cylindrical conductive support has an end part having an inner circumferential surface having a surface roughness Rz of from 3 to 10 ?m. The water-repellent resin film is on the inner circumferential surface of the end part of the cylindrical conductive support. The coating film is on an outer circumferential surface of the cylindrical conductive support. The flange has a cylindrical fitting part having an outer circumferential surface secured to the inner circumferential surface of the end part of the cylindrical conductive support.Type: ApplicationFiled: January 3, 2017Publication date: July 27, 2017Inventors: Mitsuaki HIROSE, Daisuke KUBO, Hiroshi HASHIGUCHI
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Patent number: 9146483Abstract: In a photoreceptor including an electroconductive substrate; a photosensitive layer; and a protective layer, the protective layer includes a crosslinked resin having a residual group of a polycarboxylic acid compound and a group having the below-mentioned formula (10), and at least one of a compound having the below-mentioned formula (2) and a compound having the below-mentioned formula (3). wherein each of R5 and R6 independently represents a hydrogen atom, or a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms. wherein each of R7 and R8 independently represents a hydrogen atom, or an alkyl group having 1 to 4 carbon atoms, and Z1 represents a vinylene group, a divalent aromatic hydrocarbon group having 6 to 14 carbon atoms, or a 2,5-thiophenediyl group.Type: GrantFiled: February 20, 2013Date of Patent: September 29, 2015Assignee: Ricoh Company, Ltd.Inventors: Mitsuaki Hirose, Akihiro Sugino, Noboru Toriu, Keisuke Shimoyama, Tomoharu Asano
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Patent number: 9031491Abstract: An image forming apparatus, including a photoreceptor; a charger; an irradiator; an image developer; a transferer; a fixer; and a cleaning blade formed of a strip-shaped elastic blade, removing a powder from the surface of the photoreceptor passing an edge line of the blade while contacting thereto, wherein the photoreceptor includes a crosslinked resin surface layer formed of at least one of an acrylic resin and a methacrylic resin, and the cleaning blade includes a contact point with the photoreceptor, including a substrate; a mixed layer formed of at least one of an acrylic resin and a methacrylic resin, located at the surface of the substrate; and a surface layer formed of at least one of an acrylic resin and a methacrylic resin, located on the surface of the substrate.Type: GrantFiled: February 12, 2013Date of Patent: May 12, 2015Assignee: Ricoh Company, Ltd.Inventors: Tomoharu Asano, Hideo Nakamori, Akihiro Sugino, Noboru Toriu, Keisuke Shimoyama, Mitsuaki Hirose, Yohta Sakon, Masahiro Ohmori
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Patent number: 8927183Abstract: A photoreceptor including an electroconductive substrate; a photosensitive layer, which is located overlying the electroconductive substrate and which includes a charge generation material, a charge transport material having no radical polymerizability, a binder resin having no radical polymerizability, and a crosslinked polymer including a unit obtained from a first radically polymerizable monomer having three or more functional groups and no charge transport structure and a unit obtained from a second radically polymerizable monomer having a charge transport structure; and an outermost layer, which is located on the photosensitive layer and which includes a crosslinked polymer including a unit obtained from a third radically polymerizable monomer having three or more functional groups and no charge transport structure and a unit obtained from a fourth radically polymerizable monomer having a charge transport structure. An image forming method and apparatus, and a process cartridge using the photoreceptor.Type: GrantFiled: May 28, 2008Date of Patent: January 6, 2015Assignee: Ricoh Company, Ltd.Inventors: Yoshiaki Kawasaki, Akihiro Sugino, Mitsuaki Hirose
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Patent number: 8647798Abstract: A photoreceptor including an electroconductive substrate; a photosensitive layer on the electroconductive substrate; and a protection layer on the photosensitive layer, wherein the protection layer includes a radical polymerizable compound having three or more radical polymerizable groups without a charge transportable group, a monofunctional radical polymerizable compound having a specific charge transportable group and a non-radical polymerizable compound having a specific charge transportable group.Type: GrantFiled: July 24, 2012Date of Patent: February 11, 2014Assignee: Ricoh Company, Ltd.Inventors: Tomoharu Asano, Hiroshi Ikuno, Akihiro Sugino, Hideo Nakamori, Mitsuaki Hirose
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Publication number: 20130330104Abstract: A photoreceptor includes an electroconductive substrate, and a laminate structure formed of at least a charge generating layer and a charge transport layer and provided overlying the electroconductive substrate, wherein the charge transport layer contains a charge transport material, a compound represented by the following formula 1 and a compound represented by the following formula 2: in the formula 1, R1 and R2 each independently represent substituted or non-substituted alkyl groups or aromatic hydrocarbon groups and one of R1 and R2 represents a substituted or non-substituted aromatic hydrocarbon group, R1 and R2 bonded to the same nitrogen atom may be bonded together to form a substituted or non-substituted nitrogen-containing heterocyclic group, and Ar represents a substituted or non-substituted hydrocarbon group; in the formula 2, R3 and R4 each independently represent substituted or non-substituted alkyl groups or aromatic hydrocarbon groups.Type: ApplicationFiled: May 31, 2013Publication date: December 12, 2013Applicant: RICOH COMPANY, LTD.Inventors: Keisuke Shimoyama, Akihiro Sugino, Mitsuaki Hirose, Tomoharu Asano, Noboru Toriu, Hideo Nakamori
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Publication number: 20130251401Abstract: An image forming apparatus, including a photoreceptor; a charger; an irradiator; an image developer; a transferer; a fixer; and a cleaning blade formed of a strip-shaped elastic blade, removing a powder from the surface of the photoreceptor passing an edge line of the blade while contacting thereto, wherein the photoreceptor includes a crosslinked resin surface layer formed of at least one of an acrylic resin and a methacrylic resin, and the cleaning blade includes a contact point with the photoreceptor, including a substrate; a mixed layer formed of at least one of an acrylic resin and a methacrylic resin, located at the surface of the substrate; and a surface layer formed of at least one of an acrylic resin and a methacrylic resin, located on the surface of the substrate.Type: ApplicationFiled: February 12, 2013Publication date: September 26, 2013Applicant: RICOH COMPANY, LTD.Inventors: Tomoharu Asano, Hideo Nakamori, Akihiro Sugino, Noboru Toriu, Keisuke Shimoyama, Mitsuaki Hirose, Yohta Sakon, Masahiro Ohmori
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Publication number: 20130243483Abstract: In a photoreceptor including an electroconductive substrate; a photosensitive layer; and a protective layer, the protective layer includes a crosslinked resin having a residual group of a polycarboxylic acid compound and a group having the below-mentioned formula (10), and at least one of a compound having the below-mentioned formula (2) and a compound having the below-mentioned formula (3). wherein each of R5 and R6 independently represents a hydrogen atom, or a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms. wherein each of R7 and R8 independently represents a hydrogen atom, or an alkyl group having 1 to 4 carbon atoms, and Z1 represents a vinylene group, a divalent aromatic hydrocarbon group having 6 to 14 carbon atoms, or a 2,5-thiophenediyl group.Type: ApplicationFiled: February 20, 2013Publication date: September 19, 2013Inventors: Mitsuaki HIROSE, Akihiro Sugino, Noboru Toriu, Keisuke Shimoyama, Tomoharu Asano
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Patent number: 8507163Abstract: A method of manufacturing an image bearing member including forming a charge generation layer overlying an electroconductive substrate, forming a charge transport layer overlying the charge generation layer, the charge transport layer including a charge transport material having a molecular weight of from 600 to 900 and a binder resin, and forming a protection layer overlying the charge transport layer by applying a liquid application containing a polymerizable compound having a charge transport structure, a polymerizable compound having no charge transport structure, a filler, a polycarboxylic acid compound, and cyclopentanone and curing the polymerizable compound having a charge transport structure, and the polymerizable compound having no charge transport structure.Type: GrantFiled: December 11, 2009Date of Patent: August 13, 2013Assignee: Ricoh Company, Ltd.Inventors: Nozomu Tamoto, Hideo Nakamori, Mitsuaki Hirose