Patents by Inventor Yasuo Asahina

Yasuo Asahina 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: 8211605
    Abstract: There is provided a toner which contains at least a binder resin, and filler including a layered inorganic compound, wherein the layered inorganic compound is cleaved to form particles in the toner, and the particles have a breadth of 0.5 nm to 4 nm, and a length of 10 nm to 90 nm.
    Type: Grant
    Filed: March 18, 2008
    Date of Patent: July 3, 2012
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiroshi Yamada, Satoshi Mochizuki, Fumihiro Sasaki, Yasuo Asahina, Hisashi Nakajima
  • Patent number: 7939235
    Abstract: A toner includes a polyol-based resin having multiple hydroxyl groups in a molecular chain thereof in which a ratio of epoxy group to hydroxyl group is from 0.990 to 1.010. A stirring and transfer device satisfies 1000000??×?×??16000000, wherein ? represents a number of rotation per minute, ? (mm) represents a pitch and ? (mm) represents a transfer path length of the stirring and transfer device. A temperature Tin (° C.) in a development device during stirring and transfer of a two component developing agent satisfies 3020 C.<Tin<60° C., and the toner satisfies Y??0.5X+45, 5?X<40, 5?Y?35, wherein X (%) represents a degree of agglomeration of a mother toner particle and Y (%) represents a degree of agglomeration of the toner which has been preserved at 55° C. for 24 hours.
    Type: Grant
    Filed: March 13, 2008
    Date of Patent: May 10, 2011
    Assignee: Ricoh Company Limited
    Inventors: Takahiro Honda, Hiroyuki Fushimi, Fumihiro Sasaki, Hisashi Nakajima, Hiroshi Yamada, Yasuo Asahina
  • Patent number: 7935469
    Abstract: Disclosed is a developer containing toner and carrier, the toner containing as a binder resin a polyol resin having a plurality of OH groups in a molecule chain having an EX/OH ratio between epoxy groups (EX) and OH groups (OH) of 0.990 to 1.010. The rotational speed ?, pitch ? and conveyance path length ? of an stirring and conveying unit satisfies 1.0×106??×?×??16.0×106. Toner base particles having an electrostatic property satisfies 1.5<[QB/M3600]/[QB/M180]<2.5, toner having an electrostatic property satisfies 0.7<[QT/M3600]/[QT/M180]<1.3, the external additive comprises two types of fine inorganic particles having different resistance values, wherein the particle size distribution Y and added amount X of the fine inorganic particles with smaller resistance satisfy 0.1?x?2.0, and Y?2.6×10?3X+0.0048.
    Type: Grant
    Filed: March 14, 2008
    Date of Patent: May 3, 2011
    Assignee: Ricoh Company, Ltd.
    Inventors: Takahiro Honda, Hiroyuki Fushimi, Fumihiro Sasaki, Hisashi Nakajima, Yasuo Asahina
  • Patent number: 7749674
    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: July 30, 2007
    Date of Patent: July 6, 2010
    Assignee: Ricoh Company, Ltd.
    Inventors: Hideki Sugiura, Satoshi Mochizuki, Yasuaki Iwamoto, Yasuo Asahina, Kazuhiko Umemura, Tomoyuki Ichikawa, Shinya Nakayama, Koichi Sakata, Tomoko Utsumi
  • Patent number: 7642032
    Abstract: A toner including a binder resin; and a colorant, wherein a hexafluoroisopropanol (HFIP)-soluble component satisfies the following relationship: 2,000 ?Mn ?7,000 and 1.5 ?Mn/Mw ?10 wherein Mn represents a number-average molecular weight and Mw represents a weight-average molecular weight.
    Type: Grant
    Filed: October 7, 2004
    Date of Patent: January 5, 2010
    Assignee: Ricoh Company, Limited
    Inventors: Hideki Sugiura, Satoshi Mochizuki, Akihiro Kotsugai, Yasuo Asahina, Osamu Uchinokura, Hisashi Nakajima, Tomoyuki Ichikawa, Shinya Nakayama, Kohichi Sakata, Tomoko Utsumi, Hitoshi Iwatsuki, Yasuaki Iwamoto
  • Patent number: 7611815
    Abstract: An external additive for a toner for electrophotography which contains oxide fine particles which contain silicon, in which the oxide fine particles have a primary particle diameter of 30 nm to 300 nm in number average, a standard deviation ? of a particle size distribution of the primary particle diameter satisfies a relation of: R/4???R, in which the R expresses the primary particle diameter, the oxide fine particles are substantially spherical having a circularity SF1 defined as equation (1) of 100 to 130 and a circularity SF2 defined as equation (2) of 100 to 125; SF1=(L2/A)×(?/4)×100??equation (1) SF2=(P2/A)×(1/4?)×100??equation (2), in the equations, “L” expresses the absolute maximum length of the oxide fine particles; “A” expresses a projected area of the oxide fine particles; and “P” expresses a maximum perimeter of the oxide fine particles.
    Type: Grant
    Filed: July 15, 2003
    Date of Patent: November 3, 2009
    Assignee: Ricoh Company, Ltd.
    Inventors: Hideki Sugiura, Satoshi Mochizuki, Kazuhiko Umemura, Shinya Nakayama, Yasuo Asahina
  • Patent number: 7566521
    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: July 13, 2007
    Date of Patent: July 28, 2009
    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
  • Patent number: 7547497
    Abstract: A toner which is negatively charged to develop an electrostatic latent image is provided that contains a colorant; and a binder resin, wherein the toner has an acid value of from 5 to 20 mg KOH/g and an amine value of from 0.5 to 10 mg KOH/g.
    Type: Grant
    Filed: March 16, 2005
    Date of Patent: June 16, 2009
    Assignee: Ricoh Company, Ltd.
    Inventors: Osamu Uchinokura, Masami Tomita, Hisashi Nakajima, Shinya Nakayama, Koichi Sakata, Akihiro Kotsugai, Tomoyuki Ichikawa, Yasuo Asahina, Hideki Sugiura, Yasuaki Iwamoto, Satoshi Mochizuki
  • Patent number: 7521164
    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: Grant
    Filed: March 31, 2008
    Date of Patent: April 21, 2009
    Assignee: Ricoh Company, Ltd.
    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
  • Patent number: 7455942
    Abstract: It is an object of the present invention to provide a toner that can sustain favorable transferability and cleaning ability for prolonged periods; prevent photoconductor filming; exhibit no variation in image nonuniformity or external additive immersion induced by developer agitation at the time of use; excels in stability with flowability and charge stability over prolonged periods. Therefore, provided is the toner of which the quantity of aggregate of residual external additives found on the sieve of 635-mesh and 452 cm2 of mesh area, after 0.2 g of the toner on the sieve is blasted with air at a blow pressure of 0.2 MPa from 160 mm above the sieve while being air-suctioned at a suction force of 5 mmHg, and then air-suctioned at a suction force of 20 mmHg, is 4,500 or less and 5 or more.
    Type: Grant
    Filed: September 16, 2005
    Date of Patent: November 25, 2008
    Assignee: Ricoh Company, Ltd.
    Inventors: Tsuneyasu Nagatomo, Akihiro Kotsugai, Hiroshi Yamashita, Masayuki Ishii, Hiroto Higuchi, Osamu Uchinokura, Satoshi Mochizuki, Fumihiro Sasaki, Hisashi Nakajima, Hideki Sugiura, Yasuo Asahina, Shinya Nakayama, Koichi Sakata, Tomoyuki Ichikawa, Takuya Saito, Sonoh Matsuoka
  • Publication number: 20080268366
    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 31, 2008
    Publication date: October 30, 2008
    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
  • Patent number: 7442484
    Abstract: An image forming method including: forming a toner image on a support using a toner including toner particles; and feeding the support bearing the toner image thereon through a nip between an endless toner heating member and a pressure roller to fix the toner image on the support, wherein the endless toner heating member is rotated while stretched by a fixing roller and a heat roller which includes a magnetic metal and which is heated by electromagnetic induction, and wherein the pressure roller presses the support to the endless toner heating member and the fixing roller at the nip, wherein the toner particles are prepared by a polymerizing method using a binder resin containing at least a modified polyester resin.
    Type: Grant
    Filed: October 21, 2004
    Date of Patent: October 28, 2008
    Assignee: Ricoh Company Limited
    Inventors: Osamu Uchinokura, Akihiro Kotsugai, Yasuo Asahina, Tomoyuki Ichikawa, Shinya Nakayama, Kohichi Sakata, Tomoko Utsumi, Hisashi Nakajima, Yasuaki Iwamoto, Hideki Sugiura, Satoshi Mochizuki
  • Publication number: 20080233498
    Abstract: There is provided a toner which contains at least a binder resin, and filler including a layered inorganic compound, wherein the layered inorganic compound is cleaved to form particles in the toner, and the particles have a breadth of 0.5 nm to 4 nm, and a length of 10 nm to 90 nm.
    Type: Application
    Filed: March 18, 2008
    Publication date: September 25, 2008
    Inventors: Hiroshi Yamada, Satoshi Mochizuki, Fumihiro Sasaki, Yasuo Asahina, Hisashi Nakajima
  • Publication number: 20080227003
    Abstract: Disclosed is a developer containing toner and carrier, the toner containing as a binder resin a polyol resin having a plurality of OH groups in a molecule chain having an EX/OH ratio between epoxy groups (EX) and OH groups (OH) of 0.990 to 1.010. The rotational speed ?, pitch ? and conveyance path length ? of an stirring and conveying unit satisfies 1.0×106??×?×??16.0×106. Toner base particles having an electrostatic property satisfies 1.5<[QB/M3600]/[QB/M180]<2.5, toner having an electrostatic property satisfies 0.7<[QT/M3600]/[QT/M180]<1.3, the external additive comprises two types of fine inorganic particles having different resistance values, wherein the particle size distribution Y and added amount X of the fine inorganic particles with smaller resistance satisfy 0.1?x?2.0, and Y?2.6×10?3X+0.0048.
    Type: Application
    Filed: March 14, 2008
    Publication date: September 18, 2008
    Inventors: Takahiro HONDA, Hiroyuki Fushimi, Fumihiro Sasaki, Hisashi Nakajima, Yasuo Asahina
  • Publication number: 20080227000
    Abstract: An image formation method including charging an image bearing member; irradiating the surface of the image bearing member to form a latent electrostatic image thereon; developing the latent electrostatic image with a two component developing agent including a carrier and a toner including a mother toner particle and an external additive by a development device including a stirring and transfer device for transferring and stirring the developing agent; transferring the developed image to a transfer medium; and fixing the developed image on the transfer medium, wherein the toner includes a polyol-based resin as a binder resin, the polyol based resin having multiple hydroxyl groups in a molecular chain thereof in which the ratio (EX/OH) of epoxy group (EX) to hydroxyl group (OH) is from 0.990 to 1.010, the stirring and transfer device satisfies the following relationship (I): 1.0×106??×?×??16.
    Type: Application
    Filed: March 13, 2008
    Publication date: September 18, 2008
    Inventors: Takahiro HONDA, Hiroyuki Fushimi, Fumihiro Sasaki, Hisashi Nakajima, Hiroshi Yamada, Yasuo Asahina
  • Patent number: 7374851
    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: Grant
    Filed: March 20, 2006
    Date of Patent: May 20, 2008
    Assignee: Ricoh Company, Ltd.
    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
  • Patent number: 7368212
    Abstract: A toner for developing an electrostatic image, includes: a colorant; and a binder resin. The toner has a particle including at least one pore having a diameter of 10 nm or over, and a porosity thereof is in a range from 0.01 to 0.60.
    Type: Grant
    Filed: June 25, 2004
    Date of Patent: May 6, 2008
    Assignee: Ricoh Company, Ltd.
    Inventors: Hideki Sugiura, Satoshi Mochizuki, Yasuaki Iwamoto, Yasuo Asahina, Akihiro Kotsugai, Shinya Nakayama, Tomoyuki Ichikawa, Koichi Sakata, Tomoko Utsumi, Hisashi Nakajima
  • Patent number: 7368213
    Abstract: A toner containing toner particles having a core-shell structure containing a binder resin, a colorant and a release agent. The toner particles are prepared by dissolving or dispersing at least one of the binder resin and a precursor thereof in an organic solvent or a polymeric monomer and reacting the resultant in an aqueous medium for reaction, wherein the toner satisfies the following relationship: ?Tm=Tm1?Tm2>10 ° C., wherein Tm1 represents half efflux temperature of the toner and Tm2 represents half efflux temperature of a toner which is prepared by melting and kneading the toner particles and wherein a content of the release agent existing close to the surface portion of the toner particles is from 7 to 30% by volume based on an entire portion close to the surface portion of the toner particles when the content is determined by Fourier Transform Infrared Spectroscopy Attenuated Total Reflection (FTIR-ATR) method.
    Type: Grant
    Filed: March 17, 2005
    Date of Patent: May 6, 2008
    Assignee: Ricoh Company, Limited
    Inventors: Shinya Nakayama, Fumihiro Sasaki, Satoshi Mochizuki, Akihiro Kotsugai, Yasuo Asahina, Osamu Uchinokura, Hisashi Nakajima, Sonoh Matsuoka, Takuya Saito, Tomoyuki Ichikawa, Koichi Sakata
  • Publication number: 20080014527
    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: July 13, 2007
    Publication date: January 17, 2008
    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: 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