Patents by Inventor Yasuaki Iwamoto

Yasuaki Iwamoto 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: 7318989
    Abstract: To provide a toner that can provide long-term removability and high-definition images with reduced image layer thickness and densely-packed toner particles, a developer capable of forming high-quality images using the toner, a toner container for containing the toner, a process cartridge using the toner, an image forming apparatus using the toner, and an image forming method using the toner. The toner of the present invention is a toner having a substantially spherical shape with irregularities on its surface and containing at least a binder resin and a colorant, wherein a surface factor SF-1 that represents the sphericity of toner particles is 105 to 180, a surface factor SF-2 that represents the degree of surface irregularities of the toner particles is correlated with the volume-average diameter of the toner particles, and the toner particles have an inorganic oxide particle-containing layer within 1 ?m from their surfaces.
    Type: Grant
    Filed: August 3, 2006
    Date of Patent: January 15, 2008
    Assignee: Ricoh Company, Ltd.
    Inventors: Akihiro Kotsugai, Satoshi Mochizuki, Hisashi Nakajima, Yasuo Asahina, Osamu Uchinokura, Masayuki Ishii, Tomoyuki Ichikawa, Shinya Nakayama, Koichi Sakata, Tomoko Utsumi, Hitoshi Iwatsuki, Yasuaki Iwamoto, Hideki Sugiura, Masami Tomita
  • Publication number: 20070281237
    Abstract: To provide an image forming apparatus, image forming method and process cartridge, which are excellent in low-temperature fixation properties, storage stability, durability and filming resistance, can reduce generation of odor, and are capable of forming an extremely high quality image. The apparatus includes: a latent electrostatic image bearing member; a charging unit; an exposing unit; a developing unit; a transferring unit; and a fixing unit; wherein the toner comprises a binder resin and coloring agent, and the binder resin comprises a polyester-based resin (A) and polyester-based resin (B) having a melting point at least 10° C. higher than that of the polyester-based resin (A), and at least one of the polyester-based resins (A) and (B) is a resin derived from a (meth)acrylic acid modified rosin and includes a polyester unit obtained by condensation polymerization of an alcohol component and a carboxylic acid component containing a (meth)acrylic acid modified rosin.
    Type: Application
    Filed: May 30, 2007
    Publication date: December 6, 2007
    Inventors: Yasuaki IWAMOTO, Yohichiroh Watanabe, Yasutada Shitara
  • Publication number: 20070281236
    Abstract: To provide an image forming apparatus including a latent electrostatic image bearing member; a charging unit; an exposing unit; a developing unit; a transferring unit; and a fixing unit, wherein the binder resin of a toner comprises a polyester-based resin (A) and a polyester-based resin (B) having a melting point which is at least 10° C. higher than that of the polyester-based resin (A), the polyester-based resins (A) is a resin which is derived from a (meth)acrylic acid-modified rosin and which has a polyester unit obtained by condensation polymerization of an alcohol component and a carboxylic acid component containing a (meth)acrylic acid-modified rosin, and the polyester-based resin (B) is a resin derived from a fumaric acid/maleic acid-modified rosin and has a polyester unit obtained by condensation polymerization of an alcohol component and a carboxylic acid component containing any one of a fumaric acid-modified rosin and a maleic acid-modified rosin.
    Type: Application
    Filed: May 30, 2007
    Publication date: December 6, 2007
    Inventors: Yohichiroh WATANABE, Yasuaki IWAMOTO, Yasutada SHITARA
  • Publication number: 20070275318
    Abstract: A toner including toner particles including a binder resin, a colorant, and an inorganic particulate material present on a surface of the toner particles. The toner particles have a surface roughness (Ra) of from 1 to 30 nm, a standard deviation of the surface roughness of from 10 to 90 nm and include 1 to 20 convexities per 1 ?m, which have a height not less than 10 nm.
    Type: Application
    Filed: July 30, 2007
    Publication date: November 29, 2007
    Inventors: Hideki Sugiura, Satoshi Mochizuki, Yasuaki Iwamoto, Yasuo Asahina, Kazuhiko Umemura, Tomoyuki Ichikawa, Shinya Nakayama, Koichi Sakata, Tomoko Utsumi
  • Patent number: 7288353
    Abstract: A toner including toner particles including a binder resin, a colorant, and an inorganic particulate material present on a surface of the toner particles. The toner particles have a surface roughness (Ra) of from 1 to 30 nm, a standard deviation of the surface roughness of from 10 to 90 nm and include 1 to 20 convexities per 1 ?m, which have a height not less than 10 nm.
    Type: Grant
    Filed: January 20, 2004
    Date of Patent: October 30, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Hideki Sugiura, Satoshi Mochizuki, Yasuaki Iwamoto, Yasuo Asahina, Kazuhiko Umemura, Tomoyuki Ichikawa, Shinya Nakayama, Koichi Sakata, Tomoko Utsumi
  • Publication number: 20070248380
    Abstract: Provided are image forming apparatuses, image forming methods, and process cartridges using a toner that is excellent in low temperature fixing ability, hot offset resistance, and storage stability, and also generate less odor, and thus that can provide high quality images with superior fixing ability, far from tone change with time, and less likely to occur abnormal images such as density-drop and background smear. The image forming apparatuses comprise a latent electrostatic image bearing member, a charging unit, an exposing unit, a developing unit, a transfer unit, and a fixing unit, wherein the toner comprises a binder resin and a colorant, the binder resin comprises a polyester resin prepared by condensation polymerization between an alcohol component that contains an aliphatic polyvalent alcohol and a carboxylic acid component that contains (meth)acrylic acid-modified rosin.
    Type: Application
    Filed: April 20, 2007
    Publication date: October 25, 2007
    Inventors: Yasuaki IWAMOTO, Yohichiroh Watanabe, Yasutada Shitara
  • Patent number: 7261989
    Abstract: The object of the present invention is to provide a toner which has sufficiently high chargeability and less toner spent to a carrier or the like even when several tens of thousands of image sheets are output, is capable of keeping high-charge property and flowability without causing substantial background smear or toner fogging, excels in low-temperature fixing property and hot-offset property, and has a wide range of fixing temperature as well as to provide a developer, an image forming apparatus, a process cartridge, and an image forming method using the toner for developing electrostatic images. The toner of the present invention comprises a colorant, and a resin, and a fluoride compound, in which the fluoride compound exists on the surfaces of toner particles, and the atomic number ratio (F/C) of fluoride atoms to carbon atoms existing on the surfaces of the toner particles is 0.010 to 0.054.
    Type: Grant
    Filed: April 10, 2006
    Date of Patent: August 28, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Hideki Sugiura, Satoshi Mochizuki, Yasuaki Iwamoto, Yasuo Asahina, Hisashi Nakajima, Tomoyuki Ichikawa, Shinya Nakayama, Masayuki Ishii, Tomoko Utsumi, Koichi Sakata
  • Patent number: 7258959
    Abstract: The object of the present invention is to provide a developer having a sharp charge amount distribution and bringing out high-quality image without substantially smearing a charging unit, developing units, a photoconductor, and an intermediate transferring member by the developer, namely, a developer capable of providing an appropriate image density and exhibiting extremely little background smear even when used over a long period of time and repeatedly used for a number of sheets of paper as well as to provide an image forming apparatus for electrophotography using the developer.
    Type: Grant
    Filed: September 26, 2005
    Date of Patent: August 21, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Shinya Nakayama, Satoshi Mochizuki, Yasuaki Iwamoto, Yasuo Asahina, Kazuhiko Umemura, Hideki Sugiura, Hisashi Nakajima, Tomoyuki Ichikawa, Tomoko Utsumi, Koichi Sakata, Akihiro Kotsugai, Osamu Uchinokura, Masayuki Ishii
  • Publication number: 20070031748
    Abstract: To provide a toner that can provide long-term removability and high-definition images with reduced image layer thickness and densely-packed toner particles, a developer capable of forming high-quality images using the toner, a toner container for containing the toner, a process cartridge using the toner, an image forming apparatus using the toner, and an image forming method using the toner. The toner of the present invention is a toner having a substantially spherical shape with irregularities on its surface and containing at least a binder resin and a colorant, wherein a surface factor SF-1 that represents the sphericity of toner particles is 105 to 180, a surface factor SF-2 that represents the degree of surface irregularities of the toner particles is correlated with the volume-average diameter of the toner particles, and the toner particles have an inorganic oxide particle-containing layer within 1 ?m from their surfaces.
    Type: Application
    Filed: August 3, 2006
    Publication date: February 8, 2007
    Inventors: Akihiro Kotsugai, Satoshi Mochizuki, Hisashi Nakajima, Yasuo Asahina, Osamu Uchinokura, Masayuki Ishii, Tomoyuki Ichikawa, Shinya Nakayama, Koichi Sakata, Tomoko Utsumi, Hitoshi Iwatsuki, Yasuaki Iwamoto, Hideki Sugiura, Masami Tomita
  • Patent number: 7172844
    Abstract: A toner for electrophotography contains a binder resin, a colorant and a releasing agent and has a viscosity, a storage modulus (G?) and a loss modulus (G?), in which the viscosity is 1×103 Pa·s or more and a loss tangent (tan ?) as the ratio of G? to G? is 0.4 or more at temperatures from 140° C. to 170° C.
    Type: Grant
    Filed: February 24, 2004
    Date of Patent: February 6, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Kazuhiko Umemura, Satoshi Mochizuki, Yasuaki Iwamoto, Yasuo Asahina, Hideki Sugiura, Tomoyuki Ichikawa, Shinya Nakayama, Koichi Sakata, Tomoko Utsumi
  • Patent number: 7169525
    Abstract: The object of the present invention is to provide a toner which is excellent in shelf stability for a long term by producing the toner through controlling the dispersion condition of the wax around the toner surface and through improving, not only the off-set resistance of the toner for rendering the fixing properties of the toner advantageous, but also the blocking resistance of the toner, wherein the toner contains a binder resin, a colorant, and a wax, wherein the amount of the wax is 3% by mass to 21% by mass, and the amount of the wax which is present in the portion of the toner particle which is in the range of from the outermost surface to the depth of 0.3 ?m in the toner particle is in a specified range, and at least a part of the wax is present as plural individual wax dispersion particles involved in the toner particles.
    Type: Grant
    Filed: July 20, 2005
    Date of Patent: January 30, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Hideki Sugiura, Satoshi Mochizuki, Yasuaki Iwamoto, Yasuo Asahina, Kazuhiko Umemura, Tomoyuki Ichikawa, Shinya Nakayama, Tomoko Utsumi, Koichi Sakata
  • Patent number: 7166403
    Abstract: A toner capable of making compatible a transferring property, a fixing property and a cleaning property and forming a high-precision image. The toner comprises a binder resin and a colorant and is characterized in that the average circularity of the toner is at least 0.95, a ratio (D/S) between the total projection area (S) and the contact area (D) of the toner is 15% to 40%, and the contact area (D) is a total contact area between the toner and an object surface. The toner has such a shape as to be able to contact a latent image carrier with a proper contact area, has a high transferring rate and can prevent transferring dust.
    Type: Grant
    Filed: June 24, 2005
    Date of Patent: January 23, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Tomoyuki Ichikawa, Satoshi Mochizuki, Yasuaki Iwamoto, Hideki Sugiura, Tadao Takikawa, Toshihiko Kinsho, Hidetoshi Noda, Shuhei Yahiro
  • Patent number: 7163773
    Abstract: Spherical toners having excellent fusibility are disclosed. The toners are fusible at low temperatures and are excellent in preservability and therefore charge properties, flowability, and transferability do not deteriorate. The toners contain a colorant and a nitrogen-containing polyester resin, in which the concentration of nitrogen at the surface of toner particles is higher than the concentration of nitrogen of the entire particles. The ratio of the surface concentration to the overall concentration is from 1.2 to 10. Additionally, the nitrogen-containing resin is preferably a polyester resin modified by urea bonds. Also, it is preferred that the toner particles are substantially spherical having an average sphericity E of from 0.90 to 0.99.
    Type: Grant
    Filed: August 21, 2003
    Date of Patent: January 16, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Hideki Sugiura, Satoshi Mochizuki, Yasuaki Iwamoto, Kazuhiko Umemura, Yasuo Asahina, Shinya Nakayama
  • Publication number: 20060240351
    Abstract: The object of the present invention is to provide a toner which has sufficiently high chargeability and less toner spent to a carrier or the like even when several tens of thousands of image sheets are output, is capable of keeping high-charge property and flowability without causing substantial background smear or toner fogging, excels in low-temperature fixing property and hot-offset property, and has a wide range of fixing temperature as well as to provide a developer, an image forming apparatus, a process cartridge, and an image forming method using the toner for developing electrostatic images. The toner of the present invention comprises a colorant, and a resin, and a fluoride compound, in which the fluoride compound exists on the surfaces of toner particles, and the atomic number ratio (F/C) of fluoride atoms to carbon atoms existing on the surfaces of the toner particles is 0.010 to 0.054.
    Type: Application
    Filed: April 10, 2006
    Publication date: October 26, 2006
    Inventors: Hideki Sugiura, Satoshi Mochizuki, Yasuaki Iwamoto, Yasuo Asahina, Hisashi Nakajima, Tomoyuki Ichikawa, Shinya Nakayama, Masayuki Ishii, Tomoko Utsumi, Koichi Sakata
  • Publication number: 20060204883
    Abstract: A toner which includes a toner material, wherein the toner satisfies the following formula: 0° C.??Tm?20° C. where ?Tm represents Tma (° C.)?Tmb (° C.), Tma (° C.) is ½ flown-out temperature of the toner by a capillary type flow tester, and Tmb (° C.) is ½ flown-out temperature of a melt kneaded mixture of the toner by the capillary type flow tester, and wherein Tma is from 130° C. to 200° C.
    Type: Application
    Filed: March 20, 2006
    Publication date: September 14, 2006
    Inventors: Shinya Nakayama, Satoshi Mochizuki, Yasuaki Iwamoto, Yasuo Asahina, Akihiro Kotsugai, Masayuki Ishii, Osamu Uchinokura, Hisashi Nakajima, Tomoyuki Ichikawa, Tomoko Utsumi, Koichi Sakata, Hideki Sugiura, Shigeru Emoto, Junichi Awamura, Masami Tomita, Takahiro Honda, Shinichiro Yagi, Tomomi Suzuki, Hiroshi Yamada, Toshiki Nanya, Hiroto Higuchi, Fumihiro Sasaki, Naohito Shimota
  • Publication number: 20060165989
    Abstract: Provided is a resin particle comprising a resin (a) and a filler (b) contained in the particle; the particle has a volume average particle diameter of from 0.1 to 300 ?m and a shape factor of from 110 to 300; the particle has an outer shell layer (S) comprising at least a portion of the filler (b); the layer (S) is at least 0.01 ?m thick and has a thickness that is ½ or less of the maximum inscribed circle radius of the particle cross section. When used as a toner resin, it is excellent in blade cleaning properties and wide in the fixation temperature range; when employed as a paint additive or a cosmetics additive, it is excellent in masking properties; when used as paper coating additive, it is excellent in ink retention; when utilized as an abrasive, it is excellent in abrasion.
    Type: Application
    Filed: July 14, 2004
    Publication date: July 27, 2006
    Applicants: Sanyo Chemical Industries, Ltd., Ricoh Company, Ltd.
    Inventors: Tadao Takikawa, Toshihiko Kinsho, Hidetoshi Noda, Shuhei Yahiro, Yutaka Yoshida, Tomoyuki Ichikawa, Satoshi Mochizuki, Yasuaki Iwamoto, Hideki Sugiura
  • Patent number: 7029816
    Abstract: An image formation method includes the steps of charging the surface of an electrophotographic photoconductor, exposing the charged photoconductor to a light image to form a latent electrostatic image on the photoconductor, developing the latent electrostatic image using a two-component developer containing a toner and a carrier to obtain a toner image, and transferring the toner image to an image receiving material directly or via an intermediate transfer member, with the photoconductor showing a surface friction coefficient of 0.40 or less, and the toner having toner particles with an average circularity of 0.930 or more.
    Type: Grant
    Filed: June 21, 2004
    Date of Patent: April 18, 2006
    Assignee: Ricoh Company, Ltd.
    Inventors: Fumihiro Sasaki, Mitsuo Aoki, Yasuaki Iwamoto, Naohito Shimota, Kazuyuki Yazaki, Hiroaki Matsuda, Hiroshi Nakai, Kumi Hasegawa, Shinichiro Yagi, Hiroto Higuchi, Akemi Sugiyama
  • Publication number: 20060068313
    Abstract: The object of the present invention is to provide a developer having a sharp charge amount distribution and bringing out high-quality image without substantially smearing a charging unit, developing units, a photoconductor, and an intermediate transferring member by the developer, namely, a developer capable of providing an appropriate image density and exhibiting extremely little background smear even when used over a long period of time and repeatedly used for a number of sheets of paper as well as to provide an image forming apparatus for electrophotography using the developer.
    Type: Application
    Filed: September 26, 2005
    Publication date: March 30, 2006
    Inventors: Shinya Nakayama, Satoshi Mochizuki, Yasuaki Iwamoto, Yasuo Asahina, Kazuhiko Umemura, Hideki Sugiura, Hisashi Nakajima, Tomoyuki Ichikawa, Tomoko Utsumi, Koichi Sakata, Akihiro Kotsugai, Osamu Uchinokura, Masayuki Ishii
  • Publication number: 20060040194
    Abstract: The object of the present invention is to provide a toner which is excellent in shelf stability for a long term by producing the toner through controlling the dispersion condition of the wax around the toner surface and through improving, not only the off-set resistance of the toner for rendering the fixing properties of the toner advantageous, but also the blocking resistance of the toner, wherein the toner contains a binder resin, a colorant, and a wax, wherein the amount of the wax is 3% by mass to 21% by mass, and the amount of the wax which is present in the portion of the toner particle which is in the range of from the outermost surface to the depth of 0.3 ?m in the toner particle is in a specified range, and at least a part of the wax is present as plural individual wax dispersion particles involved in the toner particles.
    Type: Application
    Filed: July 20, 2005
    Publication date: February 23, 2006
    Inventors: Hideki Sugiura, Satoshi Mochizuki, Yasuaki Iwamoto, Yasuo Asahina, Kazuhiko Umemura, Tomoyuki Ichikawa, Shinya Nakayama, Tomoko Utsumi, Koichi Sakata
  • Publication number: 20050255399
    Abstract: A toner capable of making compatible a transferring property, a fixing property and a cleaning property and forming a high-precision image. The toner comprises a binder resin and a colorant and is characterized in that the average circularity of the toner is at least 0.95, a ratio (D/S) between the total projection area (S) and the contact area (D) of the toner is 15% to 40%, and the contact area (D) is a total contact area between the toner and an object surface. The toner has such a shape as to be able to contact a latent image carrier with a proper contact area, has a high transferring rate and can prevent transferring dust.
    Type: Application
    Filed: June 24, 2005
    Publication date: November 17, 2005
    Inventors: Tomoyuki Ichikawa, Satoshi Mochizuki, Yasuaki Iwamoto, Hideki Sugiura, Tadao Takikawa, Toshihiko Kinsho, Hidetoshi Noda, Shuhei Yahiro