Patents by Inventor Tsukuru Kai

Tsukuru Kai 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: 20040223792
    Abstract: A toner contained in a hopper is fed to an electrostatic conveyance member by a supply roller. With an actuator of the electrostatic conveyance member functioning, the toner is conveyed while being electrically charged at the same time, and is then supplied to a development roller. A thin layer of toner is formed on the development roller under the effect of an electric field. Since the toner is formed and charged without a mechanical layer thickness controlling member such as a doctor blade, mechanical stress acting on the toner is reduced.
    Type: Application
    Filed: February 6, 2004
    Publication date: November 11, 2004
    Inventors: Katsuhiro Aoki, Tsukuru Kai, Hiroshi Ikeguchi
  • Patent number: 6792234
    Abstract: A developing device capable of obviating carrier deposition on an image carrier and uniformly distributing toner on a developer carrier is disclosed. A developer deposited on the developer carrier and moved away from a metering member rises in the form of a magnet brush, falls down, and again rises in accordance with the movement of the developer carrier. The toner of the developer is efficiently agitated in the axial direction of the developer carrier in a narrow zone between the first metering member and a developing zone.
    Type: Grant
    Filed: February 27, 2002
    Date of Patent: September 14, 2004
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiroshi Ikeguchi, Tsukuru Kai, Takeyoshi Sekine, Toshihiko Yamanaka
  • Publication number: 20040175207
    Abstract: An electrophotographic image forming apparatus of the present invention frees images from various defects including the thinning of horizontal lines, the omission of the trailing edge of an image, background contamination, granularity particular to a halftone image, carrier scattering, and image noise. Further, the apparatus of the present invention solves problems ascribable to patches used to sense image density. Moreover, the apparatus of the present invention faithfully reproduces tonality and has a high developing ability.
    Type: Application
    Filed: March 8, 2004
    Publication date: September 9, 2004
    Inventors: Hisashi Shoji, Tsukuru Kai, Kei Yasutomi, Nekka Matsuura, Nobutaka Takeuchi, Hirokatsu Suzuki
  • Patent number: 6782225
    Abstract: In a developing device including a plurality of developing sections each including a developer carrier that causes a developer deposited thereon to form a magnet brush and contact an image carrier, the developer carrier including: a rotatable nonmagnetic sleeve; and a stationary magnet roller accommodated in the sleeve and including a magnetic pole for scooping up the developer to the sleeve, a magnetic pole for conveying the developer deposited on the sleeve, and a main magnetic pole for causing the developer to rise on the sleeve in a form of the magnet brush. The plurality of developing sections include at least one developing section in which a flux density of the main magnetic pole in a normal direction has an attenuation ratio of 40% or above and at least one developing section in which said flux density has an attenuation ratio of 30% or below.
    Type: Grant
    Filed: November 17, 2003
    Date of Patent: August 24, 2004
    Assignee: Ricoh Company, Ltd.
    Inventors: Tsukuru Kai, Hisashi Shoji
  • Patent number: 6778805
    Abstract: An image forming apparatus of the present invention includes a lubricator for applying a lubricant to an image carrier or a process unit around the image carrier to thereby reduce friction. The apparatus of the present invention insures a uniform halftone image, prevents the trailing edge of an image from being lost, and faithfully reproduces even a horizontal line.
    Type: Grant
    Filed: June 12, 2003
    Date of Patent: August 17, 2004
    Assignee: Ricoh Company, Ltd.
    Inventors: Tsukuru Kai, Nobutaka Takeuchi, Hisashi Shoji, Kei Yasutomi, Takeyoshi Sekine, Osamu Ariizumi
  • Patent number: 6757509
    Abstract: An electrophotographic image forming apparatus of the present invention frees images from various defects including the thinning of horizontal lines, the omission of the trailing edge an image, background contamination, granularity particular to a halftone image, carrier scattering, and image noise. Further, the apparatus of the present invention solves problems ascribable to patches used to sense image density. Moreover, the apparatus of the present invention faithfully reproduces tonality and has a high developing ability.
    Type: Grant
    Filed: May 2, 2001
    Date of Patent: June 29, 2004
    Assignee: Ricoh Company, Ltd.
    Inventors: Hisashi Shoji, Tsukuru Kai, Kei Yasutomi, Nekka Matsuura, Nobutaka Takeuchi, Hirokatsu Suzuki
  • Patent number: 6757511
    Abstract: An image forming apparatus in which the flux density of a main magnetic pole for development has an attenuation ratio of 40% or above in the normal direction is disclosed. Assume that a period of time of T1 is necessary for a photoconductive element to move by a single dot at a nip for development. Also, assume that, in a single period of an alternating electric field applied to a developing sleeve as a bias, the duration of an electric field causing toner to move toward the photoconductive element is T2. Further, assume that the duration of an electric field causing the toner to move toward the sleeve is T3. Then, a relation of T1>T2>0 or a relation of T1>T3>0 holds.
    Type: Grant
    Filed: February 15, 2002
    Date of Patent: June 29, 2004
    Assignee: Ricoh Company, Ltd.
    Inventors: Naomi Sugimoto, Tsukuru Kai
  • Publication number: 20040120733
    Abstract: An image forming apparatus of the present invention includes a bias power supply for applying a bias VB to a developer carrier on which a developer is deposited. A charge potential deposited on an image carrier, which faces the developer carrier for forming a latent image thereon, is 400 V or below in absolute value.
    Type: Application
    Filed: December 11, 2003
    Publication date: June 24, 2004
    Inventors: Katsuhiro Aoki, Tsukuru Kai, Hajime Oyama, Osamu Ariizumi, Hisashi Shoji, Takashi Hodoshima, Yasuo Miyoshi
  • Publication number: 20040096245
    Abstract: An image forming apparatus of the present invention includes a developing device of the type causing a developer to form a magnet brush on the surface of a developer carrier in a developing region or nip for development. The magnet brush contacts and thereby develops a latent image formed on an image carrier. The apparatus of the present invention increases image density and faithfully reproduces even low-contrast images with a low-cost configuration. Further, the apparatus reduces image defects, including granularity and the omission of the trailing edge of an image, even if the range over which the magnet brush and image carrier contact is reduced.
    Type: Application
    Filed: November 17, 2003
    Publication date: May 20, 2004
    Inventors: Tsukuru Kai, Hisashi Shoji
  • Patent number: 6721516
    Abstract: An image forming apparatus of the present invention includes a bias power supply for applying a bias VB to a developer carrier on which a developer is deposited. A charge potential deposited on an image carrier, which faces the developer carrier for forming a latent image thereon, is 400 V or below in absolute value. Assume that the potential of the image carrier is lowered to VL after exposure, that a development potential is |VB−VL|, that the maximum set value of the development potential for development is |VB−VL|max, and that the development potential varies in a range satisfying relations: |VB−VL|≦|VB−VL|max+|VB−VL|max×0.2 |VB−VL|≧|VB−VL|max−|VB−VL|max×0.
    Type: Grant
    Filed: January 22, 2002
    Date of Patent: April 13, 2004
    Assignee: Ricoh Company, Ltd.
    Inventors: Katsuhiro Aoki, Tsukuru Kai, Hajime Oyama, Osamu Ariizumi, Hisashi Shoji, Takashi Hodoshima, Yasuo Miyoshi
  • Patent number: 6701114
    Abstract: An image forming apparatus of the present invention includes a developing device including a rotatable, nonmagnetic developer carrier and a magnetic field forming device. In a developing region where the developer carrier faces an image carrier, the magnetic field forming device causes a developer made up of toner and magnetic grains to rise on the developer carrier in the form of a magnet brush. In the developing region, the magnet brush on the developer carrier is caused to move at a higher speed than the surface of the image carrier in the same direction as and in contact with the surface of the image carrier, thereby developing the latent image. The toner of the developer is magnetic toner. Flux density set up in the developing region outside of the surface of the developer carrier in a normal direction has an attenuation ratio of 50% or above.
    Type: Grant
    Filed: January 10, 2002
    Date of Patent: March 2, 2004
    Assignee: Ricoh Company, Ltd.
    Inventors: Takeyoshi Sekine, Hiroshi Ikeguchi, Tsukuru Kai
  • Patent number: 6671484
    Abstract: An image forming apparatus of the present invention includes a developing device of the type causing a developer to form a magnet brush on the surface of a developer carrier having a magnet roller in a developing region or nip for development. The magnet brush contacts and thereby develops a latent image formed on an image carrier. The magnet roller has a main magnetic pole for development wherein the flux density in the tangential direction has a maximum variation ratio of 40 T/m or above in absolute value. The apparatus of the present invention increases image density and faithfully reproduces even low-contrast images with a low-cost configuration. Further, the apparatus reduces image defects, including granularity and the omission of the trailing edge of an image, even if the range over which the magnet brush and image carrier contact is reduced.
    Type: Grant
    Filed: September 5, 2001
    Date of Patent: December 30, 2003
    Assignee: Ricoh Company, Ltd.
    Inventors: Yasuo Miyoshi, Tsukuru Kai
  • Patent number: 6658227
    Abstract: The development is performed under a condition that |Q2|−|Q1|/|Q1≦±0.45. Here, Q1 denotes an average amount of charge on toner held on a development roller and carried toward a development region immediately before development. Q2 denotes an average amount of charge on toner immediately before development held and carried toward the development region in the state immediately after development of an electrostatic latent image on a development drum. This is effective to allow the amount of charge q/m on toner held on the development roller to have a variation rate of 45% or below and an afterimage rate R within 2%.
    Type: Grant
    Filed: July 5, 2002
    Date of Patent: December 2, 2003
    Assignee: Ricoh Company, Limited
    Inventors: Hajime Oyama, Tsukuru Kai, Katsuhiro Aoki, Takashi Hodoshima, Yasuo Miyoshi, Ichiro Kadota
  • Publication number: 20030210938
    Abstract: An image forming apparatus of the present invention includes a lubricator for applying a lubricant to an image carrier or a process unit around the image carrier to thereby reduce friction. The apparatus of the present invention insures a uniform halftone image, prevents the trailing edge of an image from being lost, and faithfully reproduces even a horizontal line.
    Type: Application
    Filed: June 12, 2003
    Publication date: November 13, 2003
    Inventors: Tsukuru Kai, Nobutaka Takeuchi, Hisashi Shoji, Kei Yasutomi, Takeyoshi Sekine, Osamu Ariizumi
  • Patent number: 6597885
    Abstract: An image forming apparatus including a developing device and an image carrier facing the developing device. The developing device includes a main magnetic pole for causing a developer to magnetically deposit on an outer periphery of a developer carrier in a form of a magnet brush. The image carrier has a coefficient of friction of 0.5 or below, and a flux density in a normal direction has an attenuation ratio of 40% or above.
    Type: Grant
    Filed: June 5, 2001
    Date of Patent: July 22, 2003
    Assignee: Ricoh Company, Ltd.
    Inventors: Tsukuru Kai, Nobutaka Takeuchi, Hisashi Shoji, Kei Yasutomi, Takeyoshi Sekine, Osamu Ariizumi
  • Patent number: 6597884
    Abstract: An electrophotographic image forming apparatus of the present invention deposits charged toner on a latent image formed on a photoconductive drum or similar image carrier to thereby produce a corresponding toner image. The apparatus includes a toner flying device for electrostatically conveying the toner along the conveying surface of a conveyance board to one end of the conveyance board. The toner is caused to fly toward the image carrier from the end of the conveyance board.
    Type: Grant
    Filed: September 10, 2001
    Date of Patent: July 22, 2003
    Assignee: Ricoh Company, Ltd.
    Inventors: Yohichiroh Miyaguchi, Takeshi Takemoto, Hiroyuki Okamoto, Chikara Imai, Katsuo Sakai, Nobuaki Kondou, Tsukuru Kai, Makoto Obu
  • Publication number: 20030086722
    Abstract: An image forming apparatus of the present invention includes a casing, an image forming unit, and an air conditioning device. The image forming unit includes a case accommodating at least a photoconductive element therein and formed with an opening for image transfer via which the photoconductive element is partly exposed to the outside. The opening is the only opening that might allow substances harmful to image formation into the case when the image forming unit is mounted to the casing. The air conditioning device removes the harmful substances flowing into the image forming unit from the outside.
    Type: Application
    Filed: October 11, 2002
    Publication date: May 8, 2003
    Inventors: Yasushi Nakazato, Yusuke Takeda, Tsukuru Kai, Satoshi Muramatsu, Masanori Suzuki, Yasuo Suzuki, Kazuyuki Shimada
  • Publication number: 20030049050
    Abstract: An image forming apparatus includes a photoconductive element including a conductive support rotatably supported and a charge injection layer and a surface protection layer sequentially laminated on the conductive support. A charger includes a conductive body for injecting, when a preselected voltage is applied thereto, a charge in the charge injection layer in contact with the surface protection layer. A writing unit exposes the charged surface of the photoconductive element imagewise to thereby locally vary the potential deposited on the photoconductive element and electrostatically form a latent image. A developing unit develops the latent image to thereby produce a corresponding toner image. The toner image is transferred from the photoconductive element to a recording medium.
    Type: Application
    Filed: October 25, 2002
    Publication date: March 13, 2003
    Inventors: Masahiko Shakuto, Tsukuru Kai, Hidetoshi Yano, Takahiko Tokumasu, Toshihiko Baba, Hiroshi Ikuno, Kei Yasutomi, Hirokatsu Suzuki, Nobutaka Takeuchi, Toshihiko Baba
  • Publication number: 20030035663
    Abstract: The development is performed under a condition that |Q2|−|Q1|/|Q1≦±0.45. Here, Q1 denotes an average amount of charge on toner held on a development roller and carried toward a development region immediately before development. Q2 denotes an average amount of charge on toner immediately before development held and carried toward the development region in the state immediately after development of an electrostatic latent image on a development drum. This is effective to allow the amount of charge q/m on toner held on the development roller to have a variation rate of 45% or below and an afterimage rate R within 2%.
    Type: Application
    Filed: July 5, 2002
    Publication date: February 20, 2003
    Inventors: Hajime Oyama, Tsukuru Kai, Katsuhiro Aoki, Takashi Hodoshima, Yasuo Miyoshi, Ichiro Kadota
  • Patent number: 6505014
    Abstract: An image forming apparatus of the present invention includes an image carrier made up of a conductive base and photoconductive layer and a toner carrier to which a bias for development is applied. The toner carrier conveys toner deposited thereon to a developing position where the toner carrier faces the image carrier, thereby developing a latent image formed on the image carrier. The apparatus effects low-voltage development that protects the image carrier from electrostatic fatigue, obviates background contamination, and realizes image density as high as 0.5 ×10−3 g/cm2 or above in terms of the amount of toner deposition. Further, the apparatus implements faithful development of the latent image by reducing the edge effect. An image forming process unit removable from the apparatus is also disclosed.
    Type: Grant
    Filed: September 28, 2001
    Date of Patent: January 7, 2003
    Assignee: Ricoh Company, Ltd.
    Inventors: Katsuhiro Aoki, Hisashi Shoji, Tsukuru Kai, Hajime Oyama, Noriyoshi Tarumi, Takashi Hodoshima, Yasuo Miyoshi