Patents by Inventor Koh Ishigami
Koh Ishigami 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: 20100159382Abstract: A carrier has an impedance Z having a frequency dependence, obtained by alternating current impedance measurement. When the frequency dependence is fitted by a fitting function, parameter ? lies in a range of 0.70 to 0.90 in an electric field of 103 V/cm.Type: ApplicationFiled: December 7, 2009Publication date: June 24, 2010Applicant: CANON KABUSHIKI KAISHAInventors: Juun Horie, Takeshi Yamamoto, Manami Haraguchi, Kenta Kubo, Tomoaki Miyazawa, Hirokazu Usami, Yoshinobu Baba, Koh Ishigami, Kazuo Uchida, Katsuhiro Watanabe, Jumpei Shirono
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Publication number: 20100143833Abstract: A magnetic carrier is provided which uses a toner having high coloring power and enables development to be performed at low electric field intensity and can form high quality images while keeping gradation characteristics. The magnetic carrier includes magnetic carrier particles including at least porous magnetic core particles and a resin. The electric field intensity just before the break-down of the magnetic carrier is 1,300 V/cm or more and 5,000 V/cm or less.Type: ApplicationFiled: January 21, 2010Publication date: June 10, 2010Applicant: CANON KABUSHIKI KAISHAInventors: Yoshinobu Baba, Koh Ishigami, Tomoko Endo, Hiroyuki Fujikawa, Kunihiko Nakamura, Nozomu Komatsu, Chika Inoue, Takayuki Itakura
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Publication number: 20100136473Abstract: A magnetic carrier which has magnetic carrier particles each having at least porous magnetic core particles and a resin, in which, in a backscattered electron image of the magnetic carrier particles, photographed with a scanning electron microscope as taken at an accelerating voltage of 2.0 kV, magnetic carrier particles having area proportion S1 found from a specific expression (1) of from 0.5 area % or more to 8.0 area % or less are in a proportion of 80% by number or more in the magnetic carrier, an average proportion Av1 of the total area of portions having a high luminance which come from a metal oxide on the magnetic carrier particles to the total projected area of the magnetic carrier particles is from 0.5 area % or more to 8.0 area % or less, and an average proportion Av2 found from a specific expression (2) is 10.0 area % or less.Type: ApplicationFiled: January 21, 2010Publication date: June 3, 2010Applicant: CANON KABUSHIKI KAISHAInventors: Koh Ishigami, Hiroyuki Fujikawa, Kunihiko Nakamura, Nozomu Komatsu, Chika Inoue, Tomoko Endo, Yoshinobu Baba, Takayuki Itakura
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Publication number: 20100119967Abstract: 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: ApplicationFiled: January 21, 2010Publication date: May 13, 2010Applicant: 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: 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: 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: 7629100Abstract: An object of the present invention is to provide a toner which: is excellent in fixing ability such as low-temperature fixability, hot offset property, and separability even in a fixing system excellent in quick start property and energy saving property; has high gloss; and is excellent in development stability and transferability irrespective of environments.Type: GrantFiled: August 20, 2007Date of Patent: December 8, 2009Assignee: Canon Kabushiki KaishaInventors: Naoki Okamoto, Tetsuya Ida, Koh Ishigami, Kazuo Terauchi, Yojiro Hotta, Noriyoshi Umeda, Yoshinobu Baba, Takayuki Itakura
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Patent number: 7611813Abstract: Provided a toner including at least: toner particles each containing at least a binder resin, a release agent, and a colorant; and an inorganic fine powder, in which: a degree of aggregation Y1 at a time of compression (200 kpa) of the toner satisfies a relationship of 15?Y1?35, and a degree of aggregation Y2 at a time of non-compression of the toner satisfies a relationship of 7?Y2?15; and a highest endothermic peak of the toner is present in a temperature range of 30 to 200° C. in an endothermic curve measured with a differential scanning calorimeter (DSC), and a peak temperature Tsc (° C.) of the highest endothermic peak satisfies a relationship of 60?Tsc?130.Type: GrantFiled: January 30, 2007Date of Patent: November 3, 2009Assignee: Canon Kabushiki KaishaInventors: Tetsuya Ida, Takeshi Ootsu, Koh Ishigami, Naoki Okamoto, Nozomu Komatsu, Noriyoshi Umeda, Yoshinobu Baba, Takayuki Itakura, Takeshi Naka, Hirohide Tanikawa
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Publication number: 20090047592Abstract: An object of the present invention is to provide a toner which: is excellent in fixing ability such as low-temperature fixability, hot offset property, and separability even in a fixing system excellent in quick start property and energy saving property; has high gloss; and is excellent in development stability and transferability irrespective of environments.Type: ApplicationFiled: August 20, 2007Publication date: February 19, 2009Applicant: CANON KABUSHIKI KAISHAInventors: Naoki Okamoto, Tetsuya Ida, Koh Ishigami, Kazuo Terauchi, Yojiro Hotta, Noriyoshi Umeda, Yoshinobu Baba, Takayuki Itakura
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Publication number: 20080286668Abstract: An object of the present invention is to provide a two-component developer which can achieve a high-definition image with a smaller toner laid-on level than a conventional one, provides a color gamut comparable to that of printing, can respond to an increase in printing speed, and allows an image with a stable tinge to be formed even in long-term use. The object can be achieved by a two-component developer containing a cyan toner and a magnetic carrier, the two-component developer being characterized in that the cyan toner has the following characteristics: (i) when the concentration of the cyan toner in a solution of the cyan toner in chloroform is represented by Cc (mg/ml) and the absorbance of the solution at a wavelength of 712 nm is represented by A712, a relationship between Cc and A712 satisfies the relationship of 2.00<A712/Cc<8.15; (ii) the lightness L* and chroma C* of the cyan toner determined in a powder state satisfy the relationships of 25.0?L*?40.0 and 50.0?C*?60.Type: ApplicationFiled: July 29, 2008Publication date: November 20, 2008Applicant: CANON KABUSHIKI KAISHAInventors: Koh Ishigami, Kazuo Terauchi, Noriyoshi Umeda, Tetsuya Ida, Naoki Okamoto, Yojiro Hotta, Yoshinobu Baba, Takayuki Itakura, Takeshi Yamamoto, Manami Haraguchi, Kenta Kubo
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Publication number: 20080187338Abstract: An image forming apparatus, wherein the following formulae are satisfied: 0.22 ? ( M / S ) L ? 0.4 , ? ( Q M ) L = Vc ( Lt 2 ? ? 0 ? ? t + Ld ? 0 ? ? d ) × ( M S ) L ( Dt ? ? max - Dt 0.1 ) { ? × ( M S ) L - 0.1 } ? ( Lt 2 ? ? 0 ? ? t + Ld ? 0 ? ? d ) × ( M S ) L 500 ? ?? ? ( Dt ? ? max - Dt 0.1 ) { ? × ( M S ) L - 0.1 } ? ( Lt 2 ? ? 0 ? ? t + Ld ? 0 ? ? d ) × ( M S ) L 150 ?? ? ( Dt ? ? max - Dt 0.1 ) { ? × ( M S ) L - 0.Type: ApplicationFiled: January 30, 2008Publication date: August 7, 2008Applicant: CANON KABUSHIKI KAISHAInventors: Takeshi Yamamoto, Manami Haraguchi, Kenta Kubo, Yoshinobu Baba, Koh Ishigami
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Patent number: 7396626Abstract: The present invention provides a toner improved in dispersibility of a colorant in the toner particles and excellent in the color reproducibility including color mixability and transparency. The toner is also excellent in the stability in long-term of the chargeability and capable of forming images maintaining high image quality. The present invention provides a toner for forming a full-color image which includes at least toner particles containing a binder resin, a colorant and a wax, and inorganic fine particles, wherein the binder resin comprises a resin having polyester units which is synthesized by use of an aromatic carboxylic acid titanium compound as a catalyst, and the inorganic fine particles comprise fine titanium oxide particles.Type: GrantFiled: September 14, 2005Date of Patent: July 8, 2008Assignee: Canon Kabushiki KaishaInventors: Hiroyuki Fujikawa, Nobuyoshi Sugahara, Takayuki Itakura, Naoki Okamoto, Koh Ishigami, Yoshinobu Baba, Hirohide Tanikawa
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Patent number: 7396629Abstract: An image forming method and an image forming apparatus are disclosed in which an electrostatic latent image is formed on a photosensitive member surface by using a two-component developer including a toner and carrier. The photosensitive member surface has a specific modulus of elastic deformation and includes a charge transport layer with a specific thickness. The toner has a specific weight-average particle diameter. The carrier has a specific volume-average particle diameter and a specific circularity, and contains 20% by number or less of particles having a value of “average circularity?2?” where ? is standard deviation of carrier circularity.Type: GrantFiled: April 26, 2005Date of Patent: July 8, 2008Assignee: Canon Kabushiki KaishaInventors: Yoshinobu Baba, Hiroyuki Fujikawa, Nobuyoshi Sugahara, Koh Ishigami, Naoki Okamoto, Takayuki Itakura
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Patent number: 7381515Abstract: In an image forming method having primarily transferring step for transferring to an intermediate transfer member a toner image formed on a photosensitive member, secondarily transferring step for transferring to a transfer material the toner image held on the intermediate transfer member, and, after the secondary transferring step, cleaning step for removing the toner remaining on the intermediate transfer member by bringing a cleaning means into contact with the intermediate transfer member, the cleaning means is a fur brush or a charging roller, and the intermediate transfer member has a specific maximum displacement quantity (Sb) and has a specific elastic deformation percentage (Eb) (%); a toner which forms the toner image has a specific average circularity, has a specific maximum displacement quantity (St), and has a specific elastic deformation percentage (Et) (%); and the elastic deformation percentage of the intermediate transfer member and the elastic deformation percentage of the toner satisfy theType: GrantFiled: April 18, 2005Date of Patent: June 3, 2008Assignee: Canon Kabushiki KaishaInventors: Nobuyoshi Sugahara, Hiroyuki Fujikawa, Koh Ishigami, Naoki Okamoto, Yoshinobu Baba, Takayuki Itakura
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Publication number: 20080026313Abstract: An image forming apparatus includes an electrophotographic photosensitive member and a toner. The photosensitive member has a universal hardness of 1.5×108 to 2.3×108 N/m2, the hardness being measured in an environment of 25° C. with a humidity of 50% using a Vickers diamond indenter having a quadrangular pyramid shape with a maximum load of 6 mN, and has an elastic deformation ratio of 46% to 65%. The toner has a weight average particle diameter of 4.0 to 8.0 ?m, the average circularity of the toner having an equivalent circle diameter of at least 2 ?m is 0.915 to 0.950, the toner has a storage modulus at 80° C. of 1×105 to 1×108 Pa, and a ratio of a loss modulus G? of the toner to the storage modulus G? of the toner (G?/G?=tan ?) is equal to 1 at a temperature in the range of 60° C. to 72° C.Type: ApplicationFiled: October 1, 2007Publication date: January 31, 2008Applicant: CANON KABUSHIKI KAISHAInventors: Nobuyoshi Sugahara, Takayuki Itakura, Koh Ishigami, Hiroyuki Fujikawa, Takakuni Kobori, Hirohide Tanikawa
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Patent number: 7288348Abstract: In a color toner having toner particles which have toner base particles containing a binder resin, a colorant and a wax, and inorganic fine particles, (i) in the toner base particles, particles having a circle-equivalent diameter of 3.00 ?m or more as measured with a flow type particle image analyzer have an average circularity of from 0.920 or more to less than 0.950, (ii) in the particles having a circle-equivalent diameter of 3.00 ?m or more in the toner base particles, particles having a circularity of 0.960 or more are in a number frequency cumulative value of 40% or less; and (iii) in the particles having a circle-equivalent diameter of 3.00 ?m or more in the toner base particles, particles having a circularity of 0.920 or less are in a number frequency cumulative value of 30% or less. Also disclosed is a full-color image forming method making use of the toner.Type: GrantFiled: September 9, 2004Date of Patent: October 30, 2007Assignee: Canon Kabushiki KaishaInventors: Kazuhiko Hayami, Tetsuya Ida, Nozomu Komatsu, Yasuhiro Ichikawa, Akira Hashimoto, Hirohide Tanikawa, Takakuni Kobori, Takayuki Itakura, Hiroyuki Fujikawa, Koh Ishigami, Nobuyoshi Sugahara
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Patent number: 7279262Abstract: A magnetic carrier composed of carrier particles is provided in which each carrier particle has a carrier core including magnetic fine particles and a binder resin with the carrier core surface being coated with a coat material containing a coat resin. In the magnetic carrier, Fatom/Catom and (Fatom/Catom)/(Fcalc/Ccalc) are respectively in specific ranges, wherein Fatom and Catom represent respectively a fluorine element abundance ratio and a carbon element abundance ratio at the magnetic carrier particle surface, and Fcalc and Ccalc represent respectively a fluorine element abundance ratio and a carbon element abundance ratio which are calculable from the molecular structure of the coat resin. In addition, a two-component developer is provoded including the magnetic carrier and a toner having a specific contact angle against water.Type: GrantFiled: November 16, 2004Date of Patent: October 9, 2007Assignee: Canon Kabushiki KaishaInventors: Hiroyuki Fujikawa, Takayuki Itakura, Takakuni Kobori, Koh Ishigami, Nobuyoshi Sugahara, Yoshinobu Baba, Hirohide Tanikawa
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Patent number: 7272348Abstract: A developing method using a developing device including at least: a first developer bearing member arranged to be opposed to an image bearing member; and a second developer bearing member arranged on a downstream side of a rotation direction of the image bearing member with respect to the first developer bearing member, the developing method including developing a latent image formed on the image bearing member with a developer, in which: the developer is a two-component developer having toner and a magnetic carrier; and the developer has a degree of compression C in the range of 20 to 32% and a shearing stress obtained by shearing stress measurement under a consolidation load of 4.0×10?4 N/mm2 in the range of 0.5×10?4 to 2.5×10?4 N/mm2.Type: GrantFiled: April 26, 2005Date of Patent: September 18, 2007Assignee: Canon Kabushiki KaishaInventors: Naoki Okamoto, Hiroyuki Fujikawa, Koh Ishigami, Nobuyoshi Sugahara, Yoshinobu Baba, Takayuki Itakura
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Publication number: 20070122727Abstract: Provided a toner including at least: toner particles each containing at least a binder resin, a release agent, and a colorant; and an inorganic fine powder, in which: a degree of aggregation Y1 at a time of compression (200 kpa) of the toner satisfies a relationship of 15?Y1?35, and a degree of aggregation Y2 at a time of non-compression of the toner satisfies a relationship of 7?Y2?15; and a highest endothermic peak of the toner is present in a temperature range of 30 to 200° C. in an endothermic curve measured with a differential scanning calorimeter (DSC), and a peak temperature Tsc (° C.) of the highest endothermic peak satisfies a relationship of 60?Tsc?130.Type: ApplicationFiled: January 30, 2007Publication date: May 31, 2007Applicant: CANON KABUSHIKI KAISHAInventors: Tetsuya Ida, Takeshi Ootsu, Koh Ishigami, Naoki Okamoto, Nozomu Komatsu, Noriyoshi Umeda, Yoshinobu Baba, Takayuki Itakura, Takeshi Naka, Hirohide Tanikawa
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Publication number: 20060251451Abstract: To provide a fixing method and a fixing device with each of which an image which has high gloss that is uniform irrespective of a toner mounting amount on a recording medium can be obtained at a relatively high recording medium conveying speed.Type: ApplicationFiled: April 26, 2005Publication date: November 9, 2006Applicant: CANON KABUSHIKI KAISHAInventors: Koh Ishigami, Hiroyuki Fujikawa, Nobuyoshi Sugahara, Naoki Okamoto, Yoshinobu Baba, Takayuki Itakura