Patents by Inventor Tsutomu Onuma
Tsutomu Onuma 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: 7745089Abstract: A process for producing a toner by subjecting a polymer and a resin component containing a cross-linkable polymer capable of cross-linkingly reacting with the polymer, to cross-linking reaction in the presence of a first wax to form a wax-containing cross-linked polymer composition; mixing the wax-containing cross-linked polymer composition with at least a colorant and a second wax, followed by melt-kneading to form a toner composition; and pulverizing the toner composition to produce toner particles. Also disclosed is a toner produced by this process. The toner thus obtained is a toner whose fixing performance and anti-offset properties are well balanced and also which makes it possible to afford images having less fog and high quality, over a long period of time in environments of from low temperature and low humidity to high temperature and high humidity, and is highly durable without causing any contamination of members with which the toner comes into contact.Type: GrantFiled: September 20, 2007Date of Patent: June 29, 2010Assignee: Canon Kabushiki KaishaInventors: Nobuyuki Okubo, Tsutomu Onuma, Shuhei Moribe, Shinichiro Abe, Koji Nishikawa
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Patent number: 7457572Abstract: An image forming method and related process cartridge, the method having the steps of controlling the layer thickness of a toner on a toner bearing member by means of a toner regulating blade, and developing with the toner an electrostatic latent image formed on an electrostatic latent image bearing member, the toner regulating blade has, at its part to be kept in touch with the toner bearing member, a specific ten-point average roughness Rz and a specific ratio (area of contact portion/area of non-contact portion) at a specific face pressure, and the toner has a specific average circularity and has a specific aerated bulk density. This image forming method and process cartridge promise superior developing performance in any environment, can keep sleeve negative ghost from occurring and can keep toner melt adhesion to toner regulating blade and toner melt adhesion to toner bearing member from occurring.Type: GrantFiled: June 22, 2006Date of Patent: November 25, 2008Assignee: Canon Kabushiki KaishaInventors: Tsutomu Onuma, Yoshihiro Ogawa, Yusuke Hasegawa, Koji Nishikawa, Tomohisa Sano, Junko Nishiyama, Miho Okazaki, Takashige Kasuya
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Patent number: 7351509Abstract: A toner is disclosed including toner particles containing a binder resin and a colorant. The binder resin contains a vinyl resin. In the high-temperature GPC-RALLS-viscometer analysis of the o-dichlorobenzene-soluble matter of the toner, a weight-average molecular weigh of absolute molecular weights measured with a viscosity detector is in a specific range. In the o-dichlorobenzene-soluble matter, a component with the absolute molecular weight of 10,000 or less and a component with the absolute molecular weight of 1,000,000 or more are present in specific proportions, respectively. The intrinsic viscosity of the toner is in a specific range.Type: GrantFiled: December 17, 2004Date of Patent: April 1, 2008Assignee: Canon Kabushiki KaishaInventors: Shuhei Moribe, Nobuyuki Okubo, Tsutomu Onuma, Shinichiro Abe, Koji Nishikawa
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Publication number: 20080014522Abstract: A process for producing a toner by subjecting a polymer and a resin component containing a cross-linkable polymer capable of cross-linkingly reacting with the polymer, to cross-linking reaction in the presence of a first wax to form a wax-containing cross-linked polymer composition; mixing the wax-containing cross-linked polymer composition with at least a colorant and a second wax, followed by melt-kneading to form a toner composition; and pulverizing the toner composition to produce toner particles. Also disclosed is a toner produced by this process. The toner thus obtained is a toner whose fixing performance and anti-offset properties are well balanced and also which makes it possible to afford images having less fog and high quality, over a long period of time in environments of from low temperature and low humidity to high temperature and high humidity, and is highly durable without causing any contamination of members with which the toner comes into contact.Type: ApplicationFiled: September 20, 2007Publication date: January 17, 2008Applicant: CANON KABUSHIKI KAISHAInventors: Nobuyuki Okubo, Tsutomu Onuma, Shuhei Moribe, Shinichiro Abe, Koji Nishikawa
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Patent number: 7306889Abstract: A process for producing a toner by subjecting a polymer and a resin component containing a cross-linkable polymer capable of cross-linkingly reacting with the polymer, to cross-linking reaction in the presence of a first wax to form a wax-containing cross-linked polymer composition; mixing the wax-containing cross-linked polymer composition with at least a colorant and a second wax, followed by melt-kneading to form a toner composition; and pulverizing the toner composition to produce toner particles. Also disclosed is a toner produced by this process. The toner thus obtained is a toner whose fixing performance and anti-offset properties are well balanced and also which makes it possible to afford images having less fog and high quality, over a long period of time in environments of from low temperature and low humidity to high temperature and high humidity, and is highly durable without causing any contamination of members with which the toner comes into contact.Type: GrantFiled: December 17, 2004Date of Patent: December 11, 2007Assignee: Canon Kabushiki KaishaInventors: Nobuyuki Okubo, Tsutomu Onuma, Shuhei Moribe, Shinichiro Abe, Koji Nishikawa
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Patent number: 7288354Abstract: A toner is composed of toner particles including toner base particles containing at least a binder resin and a colorant, and inorganic fine particles. The toner base particles having a specific circle-equivalent diameter as measured with a flow type particle image analyzer have a specific average circularity. The toner base particles have a specific surface roughness as measured with a scanning probe microscope. The binder resin contains at least a vinyl resin having as partial structure a linkage formed by the reaction of a carboxyl group with an epoxy group.Type: GrantFiled: July 30, 2004Date of Patent: October 30, 2007Assignee: Canon Kabushiki KaishaInventors: Shuhei Moribe, Nobuyuki Okubo, Tsutomu Onuma, Hideto Iida, Koji Nishikawa, Takashige Kasuya
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Patent number: 7273686Abstract: In a toner comprising toner particles which comprise toner base particles containing at least a binder resin and a magnetic material, and inorganic fine particles, the toner base particles have been obtained through a pulverization step; and, the toner base particles having a circle-equivalent diameter of from 3 ?m or more to 400 ?m or less as measured with a flow type particle image analyzer have an average circularity of from 0.935 or more to less than 0.970; and the toner base particles have an average surface roughness of from 5.0 nm or more to less than 35.0 nm as measured with a scanning probe microscope. The toner can enjoy less toner consumption per sheet of images, can achieve a long lifetime in a smaller quantity of toner, and has superior developing performance in any environment.Type: GrantFiled: July 29, 2004Date of Patent: September 25, 2007Assignee: Canon Kabushiki KaishaInventors: Tsutomu Onuma, Nobuyuki Okubo, Hideto Iida, Takashige Kasuya, Koji Nishikawa, Shuhei Moribe
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Publication number: 20070059049Abstract: An image forming method having the steps of controlling the layer thickness of a toner on a toner bearing member by means of a toner regulating blade, and developing with the toner an electrostatic latent image formed on an electrostatic latent image bearing member, the toner regulating blade has, at its part to be kept in touch with the toner bearing member, a specific ten-point average roughness Rz and a specific ratio (area of contact portion/area of non-contact portion) at a specific face pressure, and the toner has a specific average circularity and has a specific aerated bulk density. This image forming method promises superior developing performance in any environment, can keep sleeve negative ghost from occurring and can keep toner melt adhesion to toner regulating blade and toner melt adhesion to toner bearing member from occurring.Type: ApplicationFiled: June 22, 2006Publication date: March 15, 2007Applicant: Canon Kabushiki KaishaInventors: Tsutomu Onuma, Yoshihiro Ogawa, Yusuke Hasegawa, Koji Nishikawa, Tomohisa Sano, Junko Nishiyama, Miho Okazaki, Takashige Kasuya
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Publication number: 20050186497Abstract: A toner is disclosed including toner particles containing a binder resin and a colorant. The binder resin contains a vinyl resin. In the high-temperature GPC-RALLS-viscometer analysis of the o-dichlorobenzene-soluble matter of the toner, a weight-average molecular weigh of absolute molecular weights measured with a viscosity detector is in a specific range. In the o-dichlorobenzene-soluble matter, a component with the absolute molecular weight of 10,000 or less and a component with the absolute molecular weight of 1,000,000 or more are present in specific proportions, respectively. The intrinsic viscosity of the toner is in a specific range.Type: ApplicationFiled: December 17, 2004Publication date: August 25, 2005Applicant: CANON KABUSHIKI KAISHAInventors: Shuhei Moribe, Nobuyuki Okubo, Tsutomu Onuma, Shinichiro Abe, Koji Nishikawa
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Publication number: 20050186499Abstract: A process for producing a toner by subjecting a polymer and a resin component containing a cross-linkable polymer capable of cross-linkingly reacting with the polymer, to cross-linking reaction in the presence of a first wax to form a wax-containing cross-linked polymer composition; mixing the wax-containing cross-linked polymer composition with at least a colorant and a second wax, followed by melt-kneading to form a toner composition; and pulverizing the toner composition to produce toner particles. Also disclosed is a toner produced by this process. The toner thus obtained is a toner whose fixing performance and anti-offset properties are well balanced and also which makes it possible to afford images having less fog and high quality, over a long period of time in environments of from low temperature and low humidity to high temperature and high humidity, and is highly durable without causing any contamination of members with which the toner comes into contact.Type: ApplicationFiled: December 17, 2004Publication date: August 25, 2005Applicant: CANON KABUSHIKI KAISHAInventors: Nobuyuki Okubo, Tsutomu Onuma, Shuhei Moribe, Shinichiro Abe, Koji Nishikawa
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Publication number: 20050048390Abstract: A toner is composed of toner particles including toner base particles containing atleast a binder resin and a colorant, and inorganic fine particles. The toner base particles having a specific circle-equivalent diameter as measured with a flow type particle image analizer have a specific average circularity. The toner base particles have a specific surface roughness as measured with a scanning probe microscope. The binder resin contains at least a vynil resin having as partial structure a linkage formed by the reaction of a carboxyl group with an epoxy group.Type: ApplicationFiled: July 30, 2004Publication date: March 3, 2005Applicant: CANON KABUSHIKI KAISHAInventors: Shuhei Moribe, Nobuyuki Okubo, Tsutomu Onuma, Hideto Iida, Koji Nishikawa, Takashige Kasuya
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Publication number: 20050026065Abstract: In a toner comprising toner particles which comprise toner base particles containing at least a binder resin and a magnetic material, and inorganic fine particles, the toner base particles have been obtained through a pulverization step; and, the toner base particles having a circle-equivalent diameter of from 3 ?m or more to 400 ?m or less as measured with a flow type particle image analyzer have an average circularity of from 0.935 or more to less than 0.970; and the toner base particles have an average surface roughness of from 5.0 nm or more to less than 35.0 nm as measured with a scanning probe microscope. The toner can enjoy less toner consumption per sheet of images, can achieve a long lifetime in a smaller quantity of toner, and has superior developing performance in any environment.Type: ApplicationFiled: July 29, 2004Publication date: February 3, 2005Applicant: CANON KABUSHIKI KAISHAInventors: Tsutomu Onuma, Nobuyuki Okubo, Hideto Iida, Takashige Kasuya, Koji Nishikawa, Shuhei Moribe
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Patent number: 6810217Abstract: A process cartridge which is detachably mountable to a main body of an image-forming apparatus has a photosensitive member, a magnetic toner-holding section provided with a magnetic toner-carrying member which transports the toner to a developing zone, and a residual magnetic toner detector capable of detecting residual toner by a change in electrostatic capacity which is caused between electrodes provided inside the magnetic toner-holding section. The magnetic toner contains at least a binder resin and a colorant, having a weight-average particle diameter of from 6.5 &mgr;m to 15.0 &mgr;m, and having a Carr's floodability index of more than 80.Type: GrantFiled: April 25, 2002Date of Patent: October 26, 2004Assignee: Canon Kabushiki KaishaInventors: Kaori Hiratsuka, Hirohide Tanikawa, Tsutomu Onuma, Nobuyuki Okubo
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Patent number: 6673506Abstract: In a toner production process having at least a kneading step, a pulverization step using a mechanical grinding machine, and a classification step, the grinding means comprises a mechanical grinding machine having at least a rotor which is a rotator attached to the center rotating shaft and a stator which is provided around the rotor, keeping a constant gap between the stator and the rotor surface, the grinding machine being so constructed that a circular space formed by keeping the gap stands airtight, and the surface of at least one of the rotor and the stator is coated by the plating of a chromium alloy containing at least chromium carbide.Type: GrantFiled: December 14, 2001Date of Patent: January 6, 2004Assignee: Canon Kabushiki KaishaInventors: Tsuneo Nakanishi, Hirohide Tanikawa, Tsutomu Onuma, Nobuyuki Okubo, Kaori Hiratsuka
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Publication number: 20030198883Abstract: A toner is composed of toner particles containing a binder resin and hydrocarbon wax wherein the binder resin includes a vinyl resin having carboxyl and a vinyl resin having as a partial structure a linkage formed by the reaction of carboxyl with epoxy. Each of the acid value of tetrahydrofuran-soluble matter of the toner, the acid value of the binder resin and the hydroxyl value of the hydrocarbon wax is in a specific range, and the acid value of the binder resin and the hydroxyl value of the hydrocarbon wax fulfill a specific relationship.Type: ApplicationFiled: April 9, 2003Publication date: October 23, 2003Inventors: Kaori Hiratsuka, Hirohide Tanikawa, Tsutomu Onuma, Nobuyuki Okubo
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Patent number: 6630275Abstract: A magnetic toner is formed of magnetic toner particles each comprising at least a binder resin and a magnetic iron oxide. The magnetic toner is provided with improved developing performances by realizing an appropriate surface-exposure state of the magnetic iron oxide, which is represented by a wettability characteristic in methanol/water mixture liquids of the magnetic toner such that it shows a transmittance of 80% for light at a wavelength of 780 nm at a methanol concentration in a range of 65-75% and a transmittance of 20% at a methanol concentration in a range of 66-76%.Type: GrantFiled: March 13, 2002Date of Patent: October 7, 2003Assignee: Canon Kabushiki KaishaInventors: Kaori Hiratsuka, Hirohide Tanikawa, Tsutomu Onuma, Nobuyuki Okubo, Tsuneo Nakanishi
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Patent number: 6589701Abstract: A dry magnetic toner is formed of magnetic toner particles comprising a binder resin and magnetic iron oxide particles. The magnetic toner is provided with excellent developing performances and transferability by controlling the presence of isolated iron-containing particles and containing a high percentage of spherical particles, the amount of which is controlled relative to the weight-average particle size of the magnetic toner and a content of particles of 3 &mgr;m or below in the magnetic toner.Type: GrantFiled: July 25, 2001Date of Patent: July 8, 2003Assignee: Canon Kabushiki KaishaInventors: Katsuhisa Yamazaki, Tsutomu Onuma, Nobuyuki Okubo, Tsuneo Nakanishi, Kaori Hiratsuka
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Patent number: 6541174Abstract: A toner for developing an electrostatic image is formed of toner particles; wherein each toner particle includes (i) 100 wt. parts of a binder resin having a glass transition point (Tg) of 50-70° C., (ii) 0.2-20 wt. parts of solid wax, and (iii) colorant particles or magnetic powder; (iv) lubricant particles carrying a liquid lubricant, so that the toner particle retains at its surface the liquid lubricant gradually released from the particles (iv). The toner may be further blended with an organically treated inorganic fine powder to provide a developer. The toner or developer retains good lubricity and releasability so that it is suitable to be used in an image forming method including means contacting a latent image-bearing means, such as a contact charging means, a contact transfer means or a contact cleaning means.Type: GrantFiled: September 1, 2000Date of Patent: April 1, 2003Assignee: Canon Kabushiki KaishaInventors: Hirohide Tanikawa, Toshiaki Nakahara, Keita Nozawa, Kazuyoshi Hagiwara, Minoru Shimojo, Rika Shinba, Masami Fujimoto, Tsutomu Onuma
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Patent number: 6537716Abstract: A toner for developing electrostatic images is comprised of a binder resin and a wax. The binder resin contains as a primary component a polyester resin having a soft segment. The wax has, in its endothermic peaks at the time of temperature rise and exothermic peaks at the time of temperature drop in the DSC curve measured using a differential scanning calorimeter; (i) an endothermic onset temperature within the range of from 50° C. to 110° C.; (ii) at least one endothermic peak P1 within the range of from 70° C. to 130° C. at the time of temperature rise; and (iii) a maximum exothermic peak at the time of temperature drop, within the range of plus-minus 9° C. of the endothermic peak P1.Type: GrantFiled: December 4, 1996Date of Patent: March 25, 2003Assignee: Canon Kabushiki KaishaInventors: Shinji Doi, Hirohide Tanikawa, Hiroaki Kawakami, Masatsugu Fujiwara, Tsutomu Onuma
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Publication number: 20030039908Abstract: A magnetic toner is formed of magnetic toner particles each comprising at least a binder resin and a magnetic iron oxide. The magnetic toner is provided with improved developing performances by realizing an appropriate surface-exposure state of the magnetic iron oxide, which is represented by a wettability characteristic in methanol/water mixture liquids of the magnetic toner such that it shows a transmittance of 80% for light at a wavelength of 780 nm at a methanol concentration in a range of 65-75% and a transmittance of 20% at a methanol concentration in a range of 66-76%.Type: ApplicationFiled: March 13, 2002Publication date: February 27, 2003Inventors: Kaori Hiratsuka, Hirohide Tanikawa, Tsutomu Onuma, Nobuyuki Okubo, Tsuneo Nakanishi