Patents by Inventor Hachiroh Tosaka

Hachiroh Tosaka 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: 9256147
    Abstract: A toner is provided including toner particles A having a circularity of greater than 0.93 and not greater than 1.00 and toner particles B having a circularity of from 0.85 to 0.93, wherein the following relationships are satisfied: 70?RA?95, 5?RB?30, 0.014?SD?0.025, and 0.940?ED?0.950, wherein RA (% by number) represents a ratio of a number of the toner particles A to a total number of toner particles included in the toner, RB (% by number) represents a ratio of a number of the toner particles B to the total number of toner particles included in the toner, SD represents a standard deviation of circularity of the toner particles A, and ED represents an average envelope degree of the toner particles B.
    Type: Grant
    Filed: January 9, 2013
    Date of Patent: February 9, 2016
    Assignee: RICOH COMPANY, LTD.
    Inventors: Hideyuki Yamaguchi, Hachiroh Tosaka, Tomoyuki Satoh
  • Patent number: 8372569
    Abstract: A toner is provided including toner particles A having a circularity of greater than 0.93 and not greater than 1.00 and toner particles B having a circularity of from 0.85 to 0.93, wherein the following relationships are satisfied: 70?RA?95, 5?RB?30, 0.014?SD?0.025, and 0.940?ED?0.950, wherein RA (% by number) represents a ratio of a number of the toner particles A to a total number of toner particles included in the toner, RB (% by number) represents a ratio of a number of the toner particles B to the total number of toner particles included in the toner, SD represents a standard deviation of circularity of the toner particles A, and ED represents an average envelope degree of the toner particles B.
    Type: Grant
    Filed: November 9, 2007
    Date of Patent: February 12, 2013
    Assignees: Ricoh Company, Ltd., Xeikon Manufacturing N.V.
    Inventors: Hideyuki Yamaguchi, Hachiroh Tosaka, Tomoyuki Satoh
  • Publication number: 20080124636
    Abstract: A toner is provided including toner particles A having a circularity of greater than 0.93 and not greater than 1.00 and toner particles B having a circularity of from 0.85 to 0.93, wherein the following relationships are satisfied: 70?RA?95, 5?RB?30, 0.014?SD?0.025, and 0.940?ED?0.950, wherein RA (% by number) represents a ratio of a number of the toner particles A to a total number of toner particles included in the toner, RB (% by number) represents a ratio of a number of the toner particles B to the total number of toner particles included in the toner, SD represents a standard deviation of circularity of the toner particles A, and ED represents an average envelope degree of the toner particles B.
    Type: Application
    Filed: November 9, 2007
    Publication date: May 29, 2008
    Inventors: Hideyuki Yamaguchi, Hachiroh Tosaka, Tomoyuki Satoh
  • Patent number: 7250240
    Abstract: The toner according to the present invention may be produced from a toner raw composition which comprises a foaming agent, a binder resin and a colorant, wherein the colorant comprises a black metal compound, the foaming agent has a volume-average particle diameter of 2 ?m to 50 ?m, the toner raw composition turns into a porous mixture while the foaming agent expands at melting and kneading the toner raw composition, and the toner obtained through milling and classifying the porous mixture has a specific density of 1.0 g/cm3 to 1.3 g/cm3, wherein the specific density is determined as follows: 1 gram of toner is pressed at 400 kgf/cm2 for five minutes in a discal cavity having a diameter of 20 mm, then the discal toner is removed; the discal toner volume (V) is calculated from the diameter and height, measured at 10 minutes after releasing the pressure on the discal toner, and the discal toner mass (W) is measured; then the specific density is determined from the following formula: Specific Density (?T)=W/V.
    Type: Grant
    Filed: June 9, 2004
    Date of Patent: July 31, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Hachiroh Tosaka, Tomiaki Ito, Yuji Natori
  • Publication number: 20050014081
    Abstract: The toner according to the present invention may be produced from a toner raw composition which comprises a foaming agent, a binder resin and a colorant, wherein the colorant comprises a black metal compound, the foaming agent has a volume-average particle diameter of 2 ?m to 50 ?m, the toner raw composition turns into a porous mixture while the foaming agent expands at melting and kneading the toner raw composition, and the toner obtained through milling and classifying the porous mixture has a specific density of 1.0 g/cm3 to 1.3 g/cm3, wherein the specific density is determined as follows: 1 gram of toner is pressed at 400 kgf/cm2 for five minutes in a discal cavity having a diameter of 20 mm, then the discal toner is removed; the discal toner volume (V) is calculated from the diameter and height, measured at 10 minutes after releasing the pressure on the discal toner, and the discal toner mass (W) is measured; then the specific density is determined from the following formula: Specific Density (?T)=W/V.
    Type: Application
    Filed: June 9, 2004
    Publication date: January 20, 2005
    Inventors: Hachiroh Tosaka, Tomiaki Ito, Yuji Natori
  • Patent number: 6737210
    Abstract: An image formation method for forming an image is proposed, which uses an image formation apparatus capable of performing (1) multi-color image formation and printing by superimposing toner images with different colors by use of a plurality of color toners with different colors, including at least a black toner, and (2) monochrome image formation and printing, using only a black toner, with a maximum transferable amount of each color toner onto the image being in a range of 4×10−3 kg/m2 to 8×10−3 kg/m2, wherein an image glossiness (GKC) obtained by the black toner in the maximum transferable amount thereof at the multi-color image printing, an image glossiness (GCC) obtained by each of the color toners other than the black toner in the maximum transferable amount thereof at the multi-color image printing, and an image glossiness (GKM) obtained by the black toner in the maximum transferable amount thereof at the monochrome image printing satisfy a particular relationship as described in
    Type: Grant
    Filed: July 12, 2002
    Date of Patent: May 18, 2004
    Assignees: Ricoh Company, Ltd., Fujitsu Limited
    Inventors: Osamu Uchinokura, Hachiroh Tosaka, Hiroshi Yamashita, Shinichi Kuramoto, Masae Nakamura, Takashi Yamamoto, Masakazu Kinoshita, Yoshimi Mizoguchi, Yoshimichi Katagiri
  • Publication number: 20030087169
    Abstract: An image formation method for forming an image is proposed, which uses an image formation apparatus capable of performing (1) multi-color image formation and printing by superimposing toner images with different colors by use of a plurality of color toners with different colors, including at least a black toner, and (2) monochrome image formation and printing, using only a black toner, with a maximum transferable amount of each color toner onto the image being in a range of 4×10−3 kg/m2 to 8×10−3 kg/m2, wherein an image glossiness (GKC) obtained by the black toner in the maximum transferable amount thereof at the multi-color image printing, an image glossiness (GCC) obtained by each of the color toners other than the black toner in the maximum transferable amount thereof at the multi-color image printing, and an image glossiness (GKM) obtained by the black toner in the maximum transferable amount thereof at the monochrome image printing satisfy a particular relationship as described in
    Type: Application
    Filed: July 12, 2002
    Publication date: May 8, 2003
    Applicant: RICOH COMPANY, LTD.
    Inventors: Osamu Uchinokura, Hachiroh Tosaka, Hiroshi Yamashita, Shinichi Kuramoto, Masae Nakamura, Takashi Yamamoto, Masakazu Kinoshita, Yoshimi Mizoguchi, Yoshimichi Katagiri
  • Patent number: 6503676
    Abstract: A toner including a binder resin; a colorant; and an external additive, wherein the external additive includes a particulate inorganic material, and a silicone oil, wherein the silicone oil is present on the particulate inorganic material in an amount of Ws by weight and present as a free silicone oil in an amount of Wfs by weight, and a free silicone degree defined as a ratio Wfs/Ws is from 10 to 70%.
    Type: Grant
    Filed: April 26, 2001
    Date of Patent: January 7, 2003
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiroshi Yamashita, Tomio Kondou, Hideki Sugiura, Hachiroh Tosaka, Osamu Uchinokura, Hitoshi Ueda, Yoshihiro Suguro
  • Patent number: 6432589
    Abstract: An image formation method for forming an image is proposed, which uses an image formation apparatus capable of performing (1) multi-color image formation and printing by superimposing toner images with different colors by use of a plurality of color toners with different colors, including at least a black toner, and (2) monochrome image formation and printing, using only a black toner, with a maximum transferable amount of each color toner onto the image being in a range of 4×10−3 kg/m2 to 8×10−3 kg/m2, wherein an image glossiness (GKC) obtained by the black toner in the maximum transferable amount thereof at the multi-color image printing, an image glossiness (GCC) obtained by each of the color toners other than the black toner in the maximum transferable amount thereof at the multi-color image printing, and an image glossiness (GKM) obtained by the black toner in the maximum transferable amount thereof at the monochrome image printing satisfy a particular relationship as described in
    Type: Grant
    Filed: August 10, 2000
    Date of Patent: August 13, 2002
    Assignees: Ricoh Company, Ltd., Fujitsu Limited
    Inventors: Osamu Uchinokura, Hachiroh Tosaka, Hiroshi Yamashita, Shinichi Kuramoto, Masae Nakamura, Takashi Yamamoto, Masakazu Kinoshita, Yoshimi Mizoguchi, Yoshimichi Katagiri
  • Publication number: 20010051270
    Abstract: A toner including a binder resin; a colorant; and an external additive, wherein the external additive includes a particulate inorganic material, and a silicone oil, wherein the silicone oil is present on the particulate inorganic material in an amount of Ws by weight and present as a free silicone oil in an amount of Wfs by weight, and a free silicone degree defined as a ratio Wfs/Ws is from 10 to 70%.
    Type: Application
    Filed: April 26, 2001
    Publication date: December 13, 2001
    Applicant: RICOH COMPANY, LTD.
    Inventors: Hiroshi Yamashita, Tomio Kondou, Hideki Sugiura, Hachiroh Tosaka, Osamu Uchinokura, Hitoshi Ueda, Yoshihiro Suguro
  • Patent number: 6004715
    Abstract: A toner for developing an electrostatic latent image, which includes ground toner particles having physical properties meeting with at least one of the following conditions (a) and (b):(a) the toner particles have an average surface roughness of at least 0.89, the average suface roughness being an average of SF1 of respective toner particles, where SF1 is defined as follows:SF1=Le/Lpwherein Le and Lp represent the length of the minimum envelope line and the peripheral length of each toner particle, respectively;(b) the toner particles have an average shape index SF3 of at least 0.63, the average shape index being a product of the average of SF1 and an average of SF2, where SF1 is as defined above and SF2 is defined as follows:SF2=4S/(P.sup.2 .times..pi.)wherein S and P represent the area and the maximum diameter of each toner particle, respectively.
    Type: Grant
    Filed: June 25, 1996
    Date of Patent: December 21, 1999
    Assignee: Ricoh Company, Ltd.
    Inventors: Masanori Suzuki, Hachiroh Tosaka, Mituo Aoki, Hiroyuki Fushimi, Akihiro Kotsugai
  • Patent number: 5882832
    Abstract: A dry toner useful for one component developer developing method is provided which has good image qualities and durability without contamination of developing apparatus. The toner includes a metal oxide in an amount of from about 10 to about 30 parts by weight per 100 parts by weight of the toner and a metal-containing azo dye.
    Type: Grant
    Filed: April 11, 1997
    Date of Patent: March 16, 1999
    Assignee: Ricoh Company, Ltd.
    Inventors: Hachiroh Tosaka, Shoichi Sugimoto, Masahide Yamashita, Shinichiroh Yagi