Patents by Inventor Akihito Ikegawa

Akihito Ikegawa 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: 5012285
    Abstract: A developing apparatus includes a photosensitive drum positioned in confronting relation to a developing sleeve. A toner accommodating tank is provided for supplying toner to the developing sleeve. The toner accommodating tank is divided into a small chamber and a supplementary chamber which are separated from one another by a partition which permits toner to be supplied from the supplementary chamber to the small chamber but which prevents the return of toner from the small chamber to the supplementary. A movable shutter selectively permits and prevents toner from being supplied from the supplementary chamber to the small chamber in accordance with operation of the apparatus.
    Type: Grant
    Filed: May 6, 1988
    Date of Patent: April 30, 1991
    Assignee: Minolta Camera Kabushiki Kaisha
    Inventors: Tateki Oka, Naoki Toyoshi, Tomoaki Yokoyama, Hiroshi Mizuno, Hiroshi Murasaki, Akihito Ikegawa, Kouichi Etou, Shuichi Nakagawa
  • Patent number: 4987452
    Abstract: An electrostatic latent image developing apparatus includes an agitating member accommodated in a casing, a roller member accommodated in a front of the casing, and a blade contacting under pressure with an outer circumferential portion of the roller member, which is arranged in the casing. Toner held on the outer circumferential portion of said roller member being supplied to develop an electrostatic latent image on the basis of rotation of the roller member while being regulated by the blade. The apparatus includes a partition member arranged between the roller member and the agitating member at an upper stream side of said blade corresponding to a rotary direction of the roller member. The casing has a space defined among the partition member, the blade, and the outer circumferential portion of the roller member.
    Type: Grant
    Filed: December 28, 1988
    Date of Patent: January 22, 1991
    Assignee: Minolta Camera Kabushiki Kaisha
    Inventors: Shuichi Nakagawa, Hiroshi Murasaki, Akihito Ikegawa, Kouichi Etou, Hiroshi Mizuno
  • Patent number: 4947212
    Abstract: An electrophotographic copying apparatus includes a main body, a developing system, removably mounted on the main body, provided with a developing device having the developing sleeve holding a carrier on the outer surface, and a toner cartridge having a toner supply roller which confronts the developing sleeve. A voltage-adjusting device adjusts the bias voltage to be supplied respectively to the developing sleeve and the toner supply roller depending on a toner color so as to generate a predetermined electric potential between the developing sleeve and the toner supply roller. The voltage adjusting device adjusts the bias voltage difference between the developing sleeve and the toner supply roller according to a saturation charge amount which is different depending on the toner color.
    Type: Grant
    Filed: May 18, 1988
    Date of Patent: August 7, 1990
    Assignee: Minolta Camera Kabushiki Kaisha
    Inventors: Akihito Ikegawa, Hiroshi Mizuno, Hiroshi Murasaki, Kouichi Etou
  • Patent number: 4924806
    Abstract: A developing apparatus is disposed adjacent to an electrostatic latent image support member in an image forming apparatus, and includes a rotatable developing sleeve confronting the electrostatic latent image support member, a magnetic roller disposed inside the developing sleeve for holding magnetic carrier on a peripheral surface of the developing sleeve, and a plurality of toner supply units confronting the developing sleeve for supplying toner to the developing sleeve. The magnetic roller accommodates a plurality of magnetic poles extending in a direction of its axis. Each toner supply unit is provided with a toner supply roller rotatable in contact with a magnetic brush held on the developing sleeve and a toner storing portion for storing the toner.
    Type: Grant
    Filed: January 19, 1988
    Date of Patent: May 15, 1990
    Assignee: Minolta Camera Kabushiki Kaisha
    Inventors: Hiroshi Mizuno, Hiroshi Murasaki, Akihito Ikegawa, Kouichi Etou
  • Patent number: 4920916
    Abstract: A developing device including a toner support member for supporting toner on its surface, which is so provided as to confront an electrostatic latent image support member and a regulation member for forming a thin layer of the toner on the toner support member, which includes a curved member for pressing the toner support member and a support member for supporting the curved member such that an area S of a space satifies an equation: 0<S.ltoreq.0.15 mm.sup.2 wherein the space is defined in a radial plane of the toner support member and the curved member and is bounded by the toner support member, the curve member and a line drawn in parallel with a normal extending through a point of contact between the toner support member and the curved member and spaced a radius of curvature of the curved member from the normal at an upstream side of the normal in a direction of rotation of the toner support member.
    Type: Grant
    Filed: March 15, 1989
    Date of Patent: May 1, 1990
    Assignee: Minolta Camera Kabushiki Kaisha
    Inventors: Hiroshi Mizuno, Toshiya Natsuhara, Yuji Enoguchi, Akihito Ikegawa, Masasi Yamamoto, Hiroshi Murasaki
  • Patent number: 4855768
    Abstract: The digital printing apparatus of this invention including ink retaining member of which the surface has a multiplicity of minute ink-wettable dot surfaces being formed as arranged with a fixed pitch in the direction of width of the recording paper. These dot surfaces are enclosed with ink-repellent surfaces. When ink is applied to the entire surface of the ink retaining member, the ink is raised only on the dot surfaces. The digital printing apparatus of this invention is provided with a multiplicity of control electrodes arranged in at least one line as spaced with a fixed pitch equalling the pitch with which the dot surfaces are spaced in the aforementioned direction. When an electrostatic force is applied between selected ones of the control electrodes and the corresponding dot surfaces, the prominences of ink held on the dot surfaces are caused to fly toward the control electrodes and land on the recording paper held between the control electrodes and the ink retaining member.
    Type: Grant
    Filed: September 26, 1988
    Date of Patent: August 8, 1989
    Assignee: Minolta Camera Kabushiki Kaisha
    Inventors: Shuji Iino, Akihito Ikegawa
  • Patent number: 4851872
    Abstract: A developing device includes a developing sleeve provided rotatably at a side of an electrostatic latent image support member, a supply member for supplying developer to the developing sleeve, a bristle height regulating member which confronts an upper portion of the developing sleeve so as to adjust an amount of the developer transported to a developing region and a plurality of magnets provided in the developing sleeve. The magnetic poles of the magnets not only extend in an axial direction of the developing sleeve but are arranged in a circumferential direction of the developing sleeve. The magnetic poles include a weak magnetic pole disposed adjacent to the upper portion of the developing sleeve and two strong magnetic poles between which the weak magnetic pole is interposed. The strong magnetic poles have a polarity different from that of the weak magnetic pole.
    Type: Grant
    Filed: May 13, 1987
    Date of Patent: July 25, 1989
    Assignee: Minolta Camera Kabushiki Kaisha
    Inventors: Hiroshi Murasaki, Hiroshi Mizuno, Akihito Ikegawa, Kouichi Etou
  • Patent number: 4819027
    Abstract: A developing apparatus includes a developing roller confronting an image support member for generating an electrostatic latent image on its surface, an accommodating tank for accommodating developing material therein, and a supply roller disposed to confront the developing roller so as to supply the developing material accommodated within the accommodating tank onto the developing roller, and is characterized in that a developing material supply width of the supply roller is smaller than the effective developing width of the developing sleeve.
    Type: Grant
    Filed: May 13, 1987
    Date of Patent: April 4, 1989
    Assignee: Minolta Camera Kabushiki Kaisha
    Inventors: Hiroshi Murasaki, Hiroshi Mizuno, Akihito Ikegawa, Kouichi Etou
  • Patent number: 4809034
    Abstract: A developing device includes a developing sleeve which is provided with a plurality of magnets so as to transport a two-component developer composed of toner and carrier to a developing region where the developing sleeve and a member bearing an electrostatic latent image confront each other, a toner reservoir, a toner supply roller for supplying the toner to the developing sleeve, which is disposed at an end portion of the toner reservoir so as to be brought into contact with the toner in the toner reservoir, a rotary member which is rotatably provided in the toner reservoir so as to be rotated in contact with the toner supply roller and a charge erasing member for erasing electric charge of electrically charged toner transported to the toner reservoir by the toner supply roller.
    Type: Grant
    Filed: May 19, 1987
    Date of Patent: February 28, 1989
    Assignee: Minolta Camera Kabushiki Kaisha
    Inventors: Hiroshi Murasaki, Hiroshi Mizuno, Akihito Ikegawa, Kouichi Etou
  • Patent number: 4786936
    Abstract: An electrostatic latent image developing device including a developing sleeve which is so provided as to confront a support member for supporting an electrostatic latent image, a toner reservoir for accommodating toner, which is formed, at its one portion, with an opening and a rotatable toner supply roller which is provided in the opening so as to confront the developing sleeve. The toner supply roller is formed, on its outer peripheral surface, with a plurality of first minute recesses and is further formed, in the first minute recesses, with a plurality of second minute recesses finer the first minute recesses.
    Type: Grant
    Filed: October 14, 1987
    Date of Patent: November 22, 1988
    Assignee: Minolta Camera Kabushiki Kaisha
    Inventors: Akihito Ikegawa, Hiroshi Mizuno, Hiroshi Murasaki, Kouichi Etou