Patents by Inventor Yojiro Hotta

Yojiro Hotta 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).

  • Patent number: 7544457
    Abstract: The present invention relates to a toner which has good property such as fixability, coloring power, developability, durability, and environmental stability and so on. More specifically, the present invention relates to a color toner containing at least a binder resin, a colorant, and a wax, in which: a wax concentration of an extract obtained by dispersing the toner into n-hexane at a concentration of 15 mg/cm3 at 23° C. and by subjecting the resultant dispersion to extraction treatment at 23° C. for 1 minute is in the range of 0.080 to 0.500 mg/cm3; an average circularity of particles each having a circle-equivalent diameter of 3 ?m or more in the toner is in the range of 0.925 to 0.965; and a content of the wax is in the range of 1 to 15 parts by mass with respect to 100 parts by mass of the binder resin.
    Type: Grant
    Filed: November 4, 2004
    Date of Patent: June 9, 2009
    Assignee: Canon Kabushiki Kaisha
    Inventors: Akira Hashimoto, Yojiro Hotta, Wakashi Iida, Kazuhiko Hayami, Yasuhiro Ichikawa, Hirohide Tanikawa
  • Publication number: 20090142683
    Abstract: The present invention relates to a toner which has good property such as fixability, coloring power, developability, durability, and environmental stability and so on. More specifically, the present invention relates to a color toner containing at least a binder resin, a colorant, and a wax, in which: a wax concentration of an extract obtained by dispersing the toner into n-hexane at a concentration of 15 mg/cm3 at 23° C. and by subjecting the resultant dispersion to extraction treatment at 23° C. for 1 minute is in the range of 0.080 to 0.500 mg/cm3; an average circularity of particles each having a circle-equivalent diameter of 3 ?m or more in the toner is in the range of 0.925 to 0.965; and a content of the wax is in the range of 1 to 15 parts by mass with respect to 100 parts by mass of the binder resin.
    Type: Application
    Filed: February 6, 2009
    Publication date: June 4, 2009
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Akira Hashimoto, Yojiro Hotta, Wakashi Iida, Kazuhiko Hayami, Yasuhiro Ichikawa, Hirohide Tanikawa
  • Publication number: 20090123856
    Abstract: 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: Application
    Filed: December 5, 2006
    Publication date: May 14, 2009
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Yojiro Hotta, Kazuo Terauchi, Kunihiko Nakamura, Hiroyuki Fujikawa, Yoshinobu Baba, Takayuki Itakura, Hirohide Tanikawa
  • Publication number: 20090047592
    Abstract: 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: Application
    Filed: August 20, 2007
    Publication date: February 19, 2009
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Naoki Okamoto, Tetsuya Ida, Koh Ishigami, Kazuo Terauchi, Yojiro Hotta, Noriyoshi Umeda, Yoshinobu Baba, Takayuki Itakura
  • Patent number: 7455947
    Abstract: The present invention provides a yellow toner which is excellent in transparency of an image formed on an OHP sheet, excellent in color reproducibility even when a light-pressure fixing unit is employed, excellent in coloring power and charge property, and is reduced in occurrence of filming. The present invention also provides a yellow toner having excellent durability and capable of contributing to the simplification or miniaturization of the constitution of an image forming apparatus. The yellow toner of the invention comprises a binder resin and a colorant, the binder resin contains at least a polyester unit, and the toner in the powder state has a lightness L* satisfying the relationship of L*>87 and has a chromaticity b* satisfying the relationship of 106<b*<120.
    Type: Grant
    Filed: May 24, 2007
    Date of Patent: November 25, 2008
    Assignee: Canon Kabushiki Kaisha
    Inventors: Tetsuya Ida, Yasuhiro Ichikawa, Wakashi Iida, Yojiro Hotta, Kazuhiko Hayami, Hirohide Tanikawa
  • Publication number: 20080286668
    Abstract: 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: Application
    Filed: July 29, 2008
    Publication date: November 20, 2008
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Koh Ishigami, Kazuo Terauchi, Noriyoshi Umeda, Tetsuya Ida, Naoki Okamoto, Yojiro Hotta, Yoshinobu Baba, Takayuki Itakura, Takeshi Yamamoto, Manami Haraguchi, Kenta Kubo
  • Patent number: 7452651
    Abstract: In a carrier comprising carrier particles; each carrier particle comprising a carrier core and a coat layer for coating the carrier core, the carrier core has a ferrite component containing i) a metal oxide having at least one of metallic elements Mg, Li and Ca, the total-sum content of which is 10 to 40 mole % based on the whole ferrite component, and ii) a metal oxide having at least one of metallic elements Mn, Cu, Cr and Zn, the total-sum content of which is 50 to 4,000 ppm based on the whole ferrite component. The carrier has a volume distribution based 50% particle diameter (D50) of from 15.0 to 55.0 ?m and a degree of surface unevenness of from 1.05 to 1.30, and the coat layer contains particles; the particles having a number-average primary particle diameter of from 10 to 500 nm.
    Type: Grant
    Filed: November 7, 2005
    Date of Patent: November 18, 2008
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yojiro Hotta, Tetsuya Ida, Wakashi Iida, Akira Hashimoto, Nozomu Komatsu, Yoshinobu Baba
  • Publication number: 20070224531
    Abstract: The present invention provides a yellow toner which is excellent in transparency of an image formed on an OHP sheet, excellent in color reproducibility even when a light-pressure fixing unit is employed, excellent in coloring power and charge property, and is reduced in occurrence of filming. The present invention also provides a yellow toner having excellent durability and capable of contributing to the simplification or miniaturization of the constitution of an image forming apparatus. The yellow toner of the invention comprises a binder resin and a colorant, the binder resin contains at least a polyester unit, and the toner in the powder state has a lightness L* satisfying the relationship of L*>87 and has a chromaticity b* satisfying the relationship of 106<b*<120.
    Type: Application
    Filed: May 24, 2007
    Publication date: September 27, 2007
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Tetsuya Ida, Yasuhiro Ichikawa, Wakashi Iida, Yojiro Hotta, Kazuhiko Hayami, Hirohide Tanikawa
  • Patent number: 7147980
    Abstract: A toner having toner particles each comprising at least a binder resin, a wax, and a colorant is used in an image forming apparatus which has a fixing means comprising a belt-shaped heating member and a pressurizing member. The binder resin contains a resin formed by a reaction between an epoxy group of a vinyl resin (A) having the epoxy group and a carboxyl group of a resin (B) having at least a polyester unit and the carboxyl group. The toner has a storage elastic modulus at a temperature of 80° C. (G? 80) in the range of 1×105 to 1×108 Pa and has a storage elastic modulus at a temperature of 160° C. (G? 160) in the range of 1×101 to 1×104 Pa.
    Type: Grant
    Filed: January 9, 2004
    Date of Patent: December 12, 2006
    Assignee: Canon Kabushiki Kaisha
    Inventors: Takayuki Itakura, Takaaki Kotaki, Yasuhiro Ichikawa, Takaaki Kaya, Wakashi Iida, Hiroyuki Fujikawa, Kazuhiko Hayami, Nobuyoshi Sugahara, Yojiro Hotta
  • Patent number: 7115349
    Abstract: Provided is toner which is excellent in developing property, transferring property, and fixing property, hardly affected by its surrounding, and has good endurance. The toner has a peak temperature of maximum endothermic peak in the range of 60 to 100° C. in an endothermic curve of differential scanning calorimetry (DSC) measurement; silica particles in the toner contain a titanium element; and the silica particles satisfy the following expressions. 0.7?(Ia1/Ib1)?2.0 0.7?(Ia2/Ib2)?2.0 where Ia1 represents a maximum intensity in the case of 2?=25.3 deg, Ib1 represents a mean intensity in the cases of 2?=25.3 deg+2.0 deg. and of 2?=25.3 deg.?2.0 deg., Ia2 represents a maximum intensity in the case of 2?=27.5 deg and Ib2 represents a mean intensity in the cases of 2?=27.5. deg+2.0 deg. and of 2?=27.5 deg.?2.0 deg.
    Type: Grant
    Filed: November 28, 2003
    Date of Patent: October 3, 2006
    Assignee: Canon Kabushiki Kaisha
    Inventors: Wakashi Iida, Kazuhiko Hayami, Takayuki Itakura, Yojiro Hotta
  • Publication number: 20060127793
    Abstract: In a carrier comprising carrier particles; each carrier particle comprising a carrier core and a coat layer for coating the carrier core, the carrier core has a ferrite component containing i) a metal oxide having at least one of metallic elements Mg, Li and Ca, the total-sum content of which is 10 to 40 mole % based on the whole ferrite component, and ii) a metal oxide having at least one of metallic elements Mn, Cu, Cr and Zn, the total-sum content of which is 50 to 4,000 ppm based on the whole ferrite component. The carrier has a volume distribution based 50% particle diameter (D50) of from 15.0 to 55.0 ?m and a degree of surface unevenness of from 1.05 to 1.30, and the coat layer contains particles; the particles having a number-average primary particle diameter of from 10 to 500 nm.
    Type: Application
    Filed: November 7, 2005
    Publication date: June 15, 2006
    Applicant: Canon Kabushiki Kaisha
    Inventors: Yojiro Hotta, Tetsuya Ida, Wakashi Iida, Akira Hashimoto, Nozomu Komatsu, Yoshinobu Baba
  • Patent number: 6929894
    Abstract: A toner is disclosed which is composed of toner particles containing at least a binder resin, a colorant and a wax, and an external additive. The wax has, in its DSC endothermic curve, a maximum endothermic peak at 55° C. to 80° C. within the temperature range from 30° C. to 160° C., the maximum endothermic peak having a half width of from 2° C. to 7° C., and the binder resin is composed chiefly of a polyester resin. The toner has a dynamic elastic modulus from 5×102 to 1×105 dN/m2 at 140° C., and its ratio to a dynamic elastic modulus at 170° C. is from 0.05 to 50, and the toner contains 10 to 20% by weight of THF-insoluble matter A of a binder resin component after 8 hours from the start of extraction and 1 to 10% by weight of THF-insoluble matter B of the binder resin component after 24 hours from the start of extraction, the ratio of A to B, B/A, being from 0.1 to 0.8. Also disclosed is a fixing method making use of this toner.
    Type: Grant
    Filed: July 10, 2002
    Date of Patent: August 16, 2005
    Assignee: Canon Kabushiki Kaisha
    Inventors: Nobuyoshi Sugahara, Masaaki Taya, Junko Yoshikawa, Takayuki Itakura, Yojiro Hotta
  • Publication number: 20050106488
    Abstract: The present invention provides a yellow toner which is excellent in transparency of an image formed on an OHP sheet, excellent in color reproducibility even when a light-pressure fixing unit is employed, excellent in coloring power and charge property, and is reduced in occurrence of filming. The present invention also provides a yellow toner having excellent durability and capable of contributing to the simplification or miniaturization of the constitution of an image forming apparatus. The yellow toner of the invention comprises a binder resin and a colorant, the binder resin contains at least a polyester unit, and the toner in the powder state has a lightness L* satisfying the relationship of L*>87 and has a chromaticity b* satisfying the relationship of 106<b*<120.
    Type: Application
    Filed: November 4, 2004
    Publication date: May 19, 2005
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Tetsuya Ida, Yasuhiro Ichikawa, Wakashi Iida, Yojiro Hotta, Kazuhiko Hayami, Hirohide Tanikawa
  • Publication number: 20050100808
    Abstract: The present invention relates to a toner which has good property such as fixability, coloring power, developability, durability, and environmental stability and so on. More specifically, the present invention relates to a color toner containing at least a binder resin, a colorant, and a wax, in which: a wax concentration of an extract obtained by dispersing the toner into n-hexane at a concentration of 15 mg/cm3 at 23° C. and by subjecting the resultant dispersion to extraction treatment at 23° C. for 1 minute is in the range of 0.080 to 0.500 mg/cm3; an average circularity of particles each having a circle-equivalent diameter of 3 ?m or more in the toner is in the range of 0.925 to 0.965; and a content of the wax is in the range of 1 to 15 parts by mass with respect to 100 parts by mass of the binder resin.
    Type: Application
    Filed: November 4, 2004
    Publication date: May 12, 2005
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Akira Hashimoto, Yojiro Hotta, Wakashi Iida, Kazuhiko Hayami, Yasuhiro Ichikawa, Hirohide Tanikawa
  • Patent number: 6808852
    Abstract: A toner characterized by improved fixing performances with no or minimum oil application is formed of: (i) a binder resin, (ii) a colorant, (iii) a hydrocarbon wax, (iv) a resin composition formed by copolymerization of a styrenic monomer together with at least one of nitrogen-containing vinyl monomers, carboxyl group-containing monomers, hydroxyl group-containing monomers and (meth)acrylate ester monomers, in the presence of a hydrocarbon unit; and (v) an organometallic compound. The binder resin (i) comprises a polyester component in a proportion of at least 60 wt. % of the binder resin. The toner has a GPC molecular weight distribution including a weight-average molecular weight (Mw) of at least 4.0×104 an a ratio Mw/Mn of at least 50 between the Mw and a number-average molecular weight (Mn).
    Type: Grant
    Filed: September 4, 2002
    Date of Patent: October 26, 2004
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yojiro Hotta, Wakashi Iida, Tetsuya Ida, Takayuki Itakura, Nozomu Komatsu
  • Publication number: 20040161688
    Abstract: A toner having toner particles each comprising at least a binder resin, a wax, and a colorant is used in an image forming apparatus which has a fixing means comprising a belt-shaped heating member and a pressurizing member. The binder resin contains a resin formed by a reaction between an epoxy group of a vinyl resin (A) having the epoxy group and a carboxyl group of a resin (B) having at least a polyester unit and the carboxyl group. The toner has a storage elastic modulus at a temperature of 80° C. (G′ 80) in the range of 1×105 to 1×108 Pa and has a storage elastic modulus at a temperature of 160° C. (G′ 160) in the range of 1×101 to 1×104 Pa.
    Type: Application
    Filed: January 9, 2004
    Publication date: August 19, 2004
    Inventors: Takayuki Itakura, Takaaki Kotaki, Yasuhiro Ichikawa, Takaaki Kaya, Wakashi Iida, Hiroyuki Fujikawa, Kazuhiko Hayami, Nobuyoshi Sugahara, Yojiro Hotta
  • Publication number: 20040137353
    Abstract: Provided is toner which is excellent in developing property, transferring property, and fixing property, hardly affected by its surrounding, and has good endurance. The toner has a peak temperature of maximum endothermic peak in the range of 60 to 100° C.
    Type: Application
    Filed: November 28, 2003
    Publication date: July 15, 2004
    Inventors: Wakashi Iida, Kazuhiko Hayami, Takayuki Itakura, Yojiro Hotta
  • Patent number: 6751424
    Abstract: An image-forming method for fixing a toner image onto a recording medium, (i) wherein when a high-gloss recording medium (G0>40) is used, an image is formed at a low-speed mode process speed of from 20 mm/sec. to less than 130 mm/sec. and, where the maximum and minimum gloss values of the fixed image (Gmax1 and Gmin1, respectively), satisfy: Gmax1≦G0+40 and Gmin1≧G0−25; and (ii) wherein when a low-gloss recording medium (0≦G0≦40) is used, an image is formed at a high-speed mode process speed of from 130 mm/sec. to 600 mm/sec. and, where values of the fixed image (Gmax2 and Gmin2, respectively), satisfy: Gmax2≦G0+20 and Gmin2≧G0−15.
    Type: Grant
    Filed: December 27, 2002
    Date of Patent: June 15, 2004
    Assignee: Canon Kabushiki Kaisha
    Inventors: Nozomu Komatsu, Takaaki Kotaki, Makoto Kanbayashi, Takaaki Kaya, Wakashi Iida, Nobuyoshi Sugahara, Takayuki Itakura, Yojiro Hotta
  • Publication number: 20040009420
    Abstract: A toner is disclosed which is composed of toner particles containing at least a binder resin, a colorant and a wax, and an external additive. The wax has, in its DSC endothermic curve, a maximum endothermic peak at 55° C. to 80° C. within the temperature range from 30° C. to 160° C., the maximum endothermic peak having a half width of from 2° C. to 7° C., and the binder resin is composed chiefly of a polyester resin. The toner has a dynamic elastic modulus from 5×102 to 1×105 dN/m2 at 140° C., and its ratio to a dynamic elastic modulus at 170° C. is from 0.05 to 50, and the toner contains 10 to 20% by weight of THF-insoluble matter A of a binder resin component after 8 hours from the start of extraction and 1 to 10% by weight of THF-insoluble matter B of the binder resin component after 24 hours from the start of extraction, the ratio of A to B, B/A, being from 0.1 to 0.8. Also disclosed is a fixing method making use of this toner.
    Type: Application
    Filed: July 10, 2002
    Publication date: January 15, 2004
    Inventors: Nobuyoshi Sugahara, Masaaki Taya, Junko Yoshikawa, Takayuki Itakura, Yojiro Hotta
  • Publication number: 20030162118
    Abstract: In an image-forming method having a fixing step of fixing a toner image onto a recording medium, and having at least a low-speed mode and a high-speed mode so as to be able to form images at different speeds;
    Type: Application
    Filed: December 27, 2002
    Publication date: August 28, 2003
    Inventors: Nozomu Komatsu, Takaaki Kotaki, Makoto Kanbayashi, Takaaki Kaya, Wakashi Iida, Nobuyoshi Sugahara, Takayuki Itakura, Yojiro Hotta