Patents by Inventor Masahide Yamashita

Masahide Yamashita 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).

  • Publication number: 20020136975
    Abstract: A toner for developing electrostatic latent images, including a matrix of a first resin selected from polyester resins, polyol resins and mixtures thereof, a plurality of domains of a second resin dispersed in the matrix and containing a wax. The amount of the wax is 2-15% by weight based on the weight of the toner The matrix is substantially free of domains of the second resin having a maximum diameter of greater than 2.0 &mgr;m. A part of the domains containing the wax having a maximum diameter of at least 0.2 &mgr;m constitutes a part of an outer surface of the toner.
    Type: Application
    Filed: November 27, 2001
    Publication date: September 26, 2002
    Inventors: Keiko Shiraishi, Masanori Suzuki, Yohichiroh Watanabe, Masahide Yamashita, Akihiro Kotsugai, Toyoshi Sawada, Kohki Katoh
  • Publication number: 20020132177
    Abstract: A toner for developing latent electrostatic images is provided which contains, in a binder resin, at least a coloring agent formed from a metal material. A saturation magnetization of the toner is 0.01 to 10 emu/g, and a true specific gravity thereof is 1.33 to 1.62 g/m3. Also provided are an electrostatic charge image developer containing the toner for developing latent electrostatic images, an image forming device, and an image forming method using the toner for developing latent electrostatic images.
    Type: Application
    Filed: November 19, 2001
    Publication date: September 19, 2002
    Inventors: Toyoshi Sawada, Masanori Suzuki, Kohki Katoh, Yohichiroh Watanabe, Masahide Yamashita, Akihiro Kotsugai, Keiko Shiraishi
  • Patent number: 6403275
    Abstract: A toner including a resin and a colorant which is dispersed in the toner and which has an average major particle diameter not greater than about 0.5 &mgr;m, wherein the following relationships are satisfied: Ta≦100 (° C.), and (Tb−Ta)≧7.0 (° C.), wherein Ta represents a temperature at which the toner has a melt viscosity of 50,000 Pa·sec and Tb represents a temperature at which the toner has a melt viscosity of 5,000 Pa·sec.
    Type: Grant
    Filed: August 31, 2000
    Date of Patent: June 11, 2002
    Assignee: Ricoh Company, Ltd.
    Inventors: Shinichi Kuramoto, Mitsuo Aoki, Hiroshi Yamashita, Fumihiro Sasaki, Tomio Kondou, Masahide Yamashita, Kazuhito Watanabe, Takashi Okada
  • Publication number: 20020037467
    Abstract: A toner including mother toner particles including at least two resins A and B and a wax each of which is incompatible with the others; and an external additive including at least one of a particulate inorganic material and a particulate resin, wherein the resins and wax form a sea-island structure in which the resin B is present like islands in a sea of the resin A and the wax is substantially included in the resin B while dispersed therein, and wherein the resin A does not include a component insoluble in tetrahydrofuran and has a weight average molecular weight of from 10,000 to 90,000.
    Type: Application
    Filed: June 26, 2001
    Publication date: March 28, 2002
    Inventors: Yohichiroh Watanabe, Masanori Suzuki, Masahide Yamashita, Keiko Shiraishi, Kazuhito Watanabe, Kohki Katoh, Toyoshi Sawada, Takuya Saito
  • Patent number: 6363229
    Abstract: A method for fixing full-color toner images on an image receiving member so that the fixed toner images selectively exhibit different glossinesses includes the step of bringing the transferred toner images into contact with a heater, with linear speeds being selectively switched in such a manner that the fixed toner images exhibit a mean surface roughness in a range of 9.5 to 16 &mgr;m at a linear speed (A), and the fixed toner images exhibit a mean surface roughness of less than 8 &mgr;m at a linear speed (B), wherein the linear speed (A) is in a range of 100 to 300 mm/sec, the linear speed (B) is lower than the linear speed (A) by 25 mm/sec or more, and the image fixing temperatures are equal at the linear speeds (A) and (B). A method for fixing full-color toner images with high glossiness on an image receiving member includes the step of bringing the transferred toner images into contact with a belt so that the fixed toner images exhibit a mean surface roughness of less than 8 &mgr;m.
    Type: Grant
    Filed: November 16, 2000
    Date of Patent: March 26, 2002
    Assignee: Ricoh Company, Ltd.
    Inventors: Keiko Shiraishi, Masanori Suzuki, Yohichiroh Watanabe, Kazuhito Watanabe, Masahide Yamashita, Kohki Katoh, Masami Tomita, Yasuo Asahina, Yasuaki Iwamoto
  • Patent number: 6303257
    Abstract: An electrophotographic toner comprising a binder resin, colorant, and an external additive, wherein the binder resin is soluble in tetrahydrofuran and includes at least a first resin component and a second resin component, wherein the first resin component has a molecular weight distribution such that a peak is present in a molecular weight range of from 1,000 to 10,000, and the second resin component has a molecular weight distribution such that a peak is present in a molecular weight range of from 100,000 to 10,000,000, wherein the peak of the first resin component is the largest, and the second resin component is present in the binder resin in an amount of from 10 to 30% by weight, and wherein the second resin component has a dynamic modulus G′ of from 100,000 to 50,000,000 dyne/cm2 when the dynamic modulus is measured by a frequency sweep method under conditions of 150° C. in temperature and 0.01 to 100 rad/sec in frequency.
    Type: Grant
    Filed: May 30, 2000
    Date of Patent: October 16, 2001
    Assignee: Ricoh Company Limited
    Inventors: Kumi Hasegawa, Yasuaki Iwamoto, Masahide Yamashita
  • Patent number: 6221549
    Abstract: A toner for developing a latent electrostatic image to a visible toner image, which is suitable for use in an image formation method in which a toner recycle system is adopted, is proposed. The toner is such a toner that a tetrahydro-furan-soluble component contained therein exhibits a sub-peak within a weight-average molecular weight range of 100,000 to 10,000,000 in a molecular weight distribution measured by gel permeation chromatography, and the toner has a water content of 5000 ppm or less when the toner has been allowed to stand at 30° C., 60%RH for 24 hours. An image formation method using this toner is also proposed.
    Type: Grant
    Filed: October 5, 1999
    Date of Patent: April 24, 2001
    Assignee: Ricoh Company, Ltd.
    Inventors: Shigeru Emoto, Masahide Yamashita, Kumi Hasegawa
  • Patent number: 5892894
    Abstract: A data re-transmission management scheme capable of improving the communication efficiency. In a data re-transmission from a server to a plurality of terminals through a communication network, any abnormal terminal including a busy terminal and/or a poor performance terminal among the plurality of terminals is detected, and each abnormal terminal is managed separately from other normal terminals, at the server. A management of data transmission and re-transmission from the server to the normal terminals is carried out first, and then a management of a re-transmission of only unreceived data of each abnormal terminal from the server to each abnormal terminal is carried out, after a completion of the data transmission and re-transmission with respect to the normal terminals.
    Type: Grant
    Filed: December 6, 1996
    Date of Patent: April 6, 1999
    Assignee: Nippon Telegraph & Telephone Corp.
    Inventors: Teruji Shiroshita, Osamu Takahashi, Masahide Yamashita
  • 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
  • Patent number: 5873018
    Abstract: An image forming apparatus comprises an intermediate transfer unit associated with a photoconductive medium. A first unit transfers a developed image on the photoconductive medium to the intermediate transfer unit such that an intermediate image on the intermediate transfer unit is formed. A second unit transfers the intermediate image from the intermediate transfer unit to a copy sheet such that a reproduced image on the copy sheet is formed. The intermediate transfer device of one aspect of the present invention comprises a surface layer of a mixture containing a friction reducing substance which reduces a coefficient of friction on the surface layer. The intermediate transfer device of another aspect of the present invention comprises a surface layer of a mixture containing a fluorocarbon polymer component and a secondary resin component which are compatible with each other, a visible developed color image being formed on the surface layer.
    Type: Grant
    Filed: April 4, 1997
    Date of Patent: February 16, 1999
    Assignee: Ricoh Company, Ltd.
    Inventors: Jun Aoto, Yasuo Hirano, Masahide Yamashita, Mitsuru Seto, Shigeru Fukuda
  • Patent number: 5863690
    Abstract: A toner image fixing method for producing a fixed image having good image qualities without hot-offset even when toner having a relatively low fixing temperature is employed by an image forming apparatus having a fixing unit including two fixing members such that an image formed of thermofusible toner on an image supporting material is fixed by heating at a nipped section of the two fixing members, wherein a ratio of a first adhesion constant to a second adhesion constant, .mu..sub.s-b (1)/.mu..sub.s-b (2), of a surface of a fixing member contacting the thermofusible toner image is less than about 8.0. An adhesion constant .mu..sub.s-b (n) is represented by:.mu..sub.s-b (n)=(cos .theta..sub.b -cos .theta..sub.s)/sin .theta..sub.b,wherein n is 1 or 2, .theta..sub.b and .theta..sub.s represent a receding contact angle and a static contact angle of the surface of the fixing member, respectively, which are measured using a liquid having a dipole moment of greater than about 3.
    Type: Grant
    Filed: February 5, 1997
    Date of Patent: January 26, 1999
    Assignee: Ricoh Company, Ltd.
    Inventor: Masahide Yamashita
  • Patent number: 5774775
    Abstract: An image forming method wherein a toner image on an image carrier is transferred in a first transfer step to an intermediate image transfer element, the transferred toner image on said intermediate image transfer element being subsequently transferred in a second transfer step to a transfer medium. The intermediate image transfer element has a surface whose angle of contact with water is at least 70 degrees and whose position in the triboelectric series is on a positive side with respect to the position of said toner when the toner on the image carrier is negatively charged and on a negative side with respect to the position of the toner when the toner on the image carrier is positively charged.
    Type: Grant
    Filed: March 26, 1996
    Date of Patent: June 30, 1998
    Assignee: Ricoh Company, Ltd.
    Inventors: Jun Aoto, Yasuo Hirano, Masahide Yamashita, Mitsuru Seto, Shigeru Fukuda
  • Patent number: 5761594
    Abstract: In an image forming apparatus of the type transferring a plurality of toner images of different colors sequentially formed on an image carrier sequentially to an endless intermediate transfer body one above the other by primary transfer, and then transferring the resulting composite color image to a transfer medium by secondary transfer, the intermediate transfer body is provided with surface energy, surface tension or adhering force which is greater than or equal to the corresponding value of the image carrier, but smaller than or equal to the corresponding value of the transfer medium.
    Type: Grant
    Filed: November 14, 1995
    Date of Patent: June 2, 1998
    Assignee: Ricoh Company, Ltd.
    Inventors: Mitsuru Seto, Shigeru Fukuda, Yasuo Hirano, Jun Aoto, Masahide Yamashita, Takashi Bisaiji, Makoto Ohsaki, Takeshi Shintani
  • Patent number: 5655199
    Abstract: An intermediate transfer type image forming apparatus for sequentially performing primary and secondary image transfer with the intermediary of an intermediate transfer medium implemented as, e.g., a belt, and the intermediate transfer member are disclosed. The image transfer medium has a lower surface resistivity on its rear than on its front or image carrying surface.
    Type: Grant
    Filed: March 20, 1996
    Date of Patent: August 5, 1997
    Assignee: Ricoh Company, Ltd.
    Inventors: Masahide Yamashita, Yasuo Hirano, Jun Aoto, Mitsuru Seto, Shigeru Fukuda
  • Patent number: 5204207
    Abstract: A magenta color liquid developer for electrophotography composed of a carrier liquid and toner particles dispersed in the carrier liquid, which toner particles contain a resin and two or more pigments including at least one water-insoluble azo pigment and a quinacridone-type pigment.
    Type: Grant
    Filed: June 18, 1991
    Date of Patent: April 20, 1993
    Assignee: Ricoh Company, Ltd.
    Inventors: Masahide Yamashita, Akihiko Gotoh
  • Patent number: 4437168
    Abstract: A real-time, on-line communication control unit is installed between a host computer and a plurality of terminals or between two host computers for the process of communication control. A plurality of basic processes relating to the communication control process are performed simultaneously by a corresponding plurality of basic processors which operate at the same time.
    Type: Grant
    Filed: January 23, 1981
    Date of Patent: March 13, 1984
    Assignee: Nippon Telegraph & Telephone Public Corp. of 1-6
    Inventors: Masahide Yamashita, Hikaru Oku, Masato Maruyama