Patents by Inventor Tetsumaru Fujita

Tetsumaru Fujita 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: 20070065179
    Abstract: An image forming apparatus may include a photoreceptor, a cleaner and a charging mechanism. The cleaner may have a blade-like shape and may remove contaminants including residual toner from the photoreceptor. The charging mechanism may include a charging brush which may have a pile length not greater than 3 mm and a pile density of not smaller than 200,000 piles/6.45 sq. cm and may rotate in a direction counter to a rotation direction of the photoreceptor while contacting the photoreceptor.
    Type: Application
    Filed: September 18, 2006
    Publication date: March 22, 2007
    Inventor: Tetsumaru Fujita
  • Publication number: 20070059034
    Abstract: An image forming apparatus and process cartridge employed in same which, when contact charging processing is implemented employing a brush roller, suppresses the generation of localized excessive discharge and suppresses a state of localized excessive discharge on a photosensitive drum surface. Charging means is configured from a brush roller in the surface of which a brush is formed, drive means for rotationally driving the brush roller, and a power source for applying a prescribed charging voltage to the brush roller, and uniformly charges the surface of the latent image carrier by bringing the brush roller into contact with the surface of the latent image carrier.
    Type: Application
    Filed: September 6, 2006
    Publication date: March 15, 2007
    Inventor: Tetsumaru Fujita
  • Patent number: 6782226
    Abstract: A developing device includes a toner bearing member holding a toner on its surface for conveyance of the toner to a development region where the toner bearing member opposes an image bearing member via a predetermined gap therebetween; a regulating member pressed against the surface of the toner bearing member for regulation of the amount of toner conveyed to the development region; and a developing bias source for applying an alternating electric field between the toner bearing member and the image bearing member. The developing device features the use of the toner bearing member including a conductive substrate formed with an elastic layer, an intermediate layer and a surface layer on the surface thereof, respective volume resistances &rgr;1, &rgr;2 and &rgr;3 of which layers satisfy a condition &rgr;2≦&rgr;1≦&rgr;3, the toner bearing member having an arithmetic average surface roughness in the range of 0.8 to 2.5 &mgr;m, and the use of the toner having a volume-average particle size of 3 to 8 &mgr;m.
    Type: Grant
    Filed: February 19, 2003
    Date of Patent: August 24, 2004
    Assignee: Minolta Co., Ltd.
    Inventors: Junji Machida, Hidetoshi Miyamoto, Tetsumaru Fujita, Masahiko Matsuura, Yoshiko Yaoi, Makoto Shimazoe, Shuichi Nakagawa
  • Publication number: 20030175055
    Abstract: A developing device includes a toner bearing member holding a toner on its surface for conveyance of the toner to a development region where the toner bearing member opposes an image bearing member via a predetermined gap therebetween; a regulating member pressed against the surface of the toner bearing member for regulation of the amount of toner conveyed to the development region; and a developing bias source for applying an alternating electric field between the toner bearing member and the image bearing member. The developing device features the use of the toner bearing member including a conductive substrate formed with an elastic layer, an intermediate layer and a surface layer on the surface thereof, respective volume resistances &rgr;1, &rgr;2 and &rgr;3 of which layers satisfy a condition &rgr;2≦&rgr;1≦&rgr;3, the toner bearing member having an arithmetic average surface roughness in the range of 0.8 to 2.5 &mgr;m, and the use of the toner having a volume-average particle size of 3 to 8 &mgr;m.
    Type: Application
    Filed: February 19, 2003
    Publication date: September 18, 2003
    Applicant: MINOLTA CO., LTD.
    Inventors: Junji Machida, Hidetoshi Miyamoto, Tetsumaru Fujita, Masahiko Matsuura, Yoshiko Yaoi, Makoto Shimazoe, Shuichi Nakagawa
  • Patent number: 6343201
    Abstract: A developing apparatus with a developing roller for conveying toners held on its surface to a developing area opposite to an image carrying member, the surface of the developing roller being moved upward from below in the developing area; a regulating member for regulating an amount of the toners to be conveyed to the developing area by the developing roller; a plate-shaped charging member for charging the toners; and a voltage applying device for applying a voltage to the charging member.
    Type: Grant
    Filed: July 27, 2000
    Date of Patent: January 29, 2002
    Assignee: Minolta Co., Ltd.
    Inventors: Minoru Wada, Tetsumaru Fujita, Ichiro Demizu, Eiji Gyotoku, Akihiro Kawasaki, Yoichi Fujieda, Hiroshi Goto
  • Patent number: 6134414
    Abstract: A developing apparatus according to the present invention for developing an electrostatic latent image formed on an image carrying member has a developer carrying member arranged opposite to an image carrying member and holding a developer, and a voltage applying device applying an AC voltage to the developer carrying member, wherein the AC voltage has a first peak potential and a second peak potential, the first peak potential being a peak potential on the side of development for supplying the developer to the image carrying member, the second peak potential being a peak potential on the side of recovery for returning the developer to the developer carrying member, and a voltage waveform of the AC voltage always has two straight line portions which differ in slopes while changing from the first peak potential to the second peak potential and/or from the second peak potential to the first peak potential.
    Type: Grant
    Filed: August 10, 1999
    Date of Patent: October 17, 2000
    Assignee: Minolta Co., Ltd.
    Inventor: Tetsumaru Fujita
  • Patent number: 5940661
    Abstract: An image forming apparatus with a charging member that allows easy removal of smears from an image forming drum. The apparatus removes smears from the image forming drum by placing a different portion of the charging member in contact with the drum. The apparatus uses a cam or a solenoid to press on the charging member to cause a different portion of the charging member to come into contact with the image forming drum.
    Type: Grant
    Filed: February 12, 1998
    Date of Patent: August 17, 1999
    Inventors: Masataka Yagi, Tamotsu Sakuraba, Tetsumaru Fujita, Narutaka Yoshida, Akira Hirota, Tsugihito Yoshiyama, Masami Matsuura, Yasuhiro Nakagami, Masayasu Haga
  • Patent number: 5754926
    Abstract: In a charging device used in a cleanerless image forming apparatus and including a charging brush in contact with an image bearing member, a scraping member is provided which is in contact with the charging brush with a predetermined amount of indentation overlap on an upstream side of a contact portion between the charging brush and the image bearing member with respect to a rotational direction of the charging brush. With such an arrangement, the developer, which is scraped from the charging brush by the scraping member and then adheres onto the image bearing member, is recharged by the charging brush so as to be collected by a developing-cleaning device.
    Type: Grant
    Filed: March 5, 1996
    Date of Patent: May 19, 1998
    Assignee: Minolta Co., Ltd.
    Inventors: Tamotsu Sakuraba, Hirofumi Hasegawa, Tetsumaru Fujita