Patents by Inventor Shigetaka Fujiwara

Shigetaka Fujiwara 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: 6412916
    Abstract: An ink jet printer is of a small size and is capable of printing high-quality images, wherein an ink with a colorant dispersed in a solvent is ejected in a direction lower than a horizontal level and is adhered to a surface of a recording medium. The recording medium is conveyed while being spaced a constant distance from ink ejecting electrodes, thereby stabilizing an electric field induced between the ink ejecting electrodes and the recording medium and stabilizing the amount of the ink ejected.
    Type: Grant
    Filed: June 27, 2000
    Date of Patent: July 2, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Mamoru Okano, Atsushi Onose, Shigetaka Fujiwara, Yoshinobu Fukano, Seiji Yonekura, Yoshiharu Nagae
  • Patent number: 6328426
    Abstract: A printer device includes a plurality of discharge electrodes provided in a slit to which ink containing charged pigment particles is supplied, a plurality of opposing electrodes opposing the plurality of discharge electrodes, a pulse electric field applicator for forming a pulse electric field between the plurality of discharge electrodes and the plurality of opposing electrodes, and auxiliary electrodes. The auxiliary electrodes are provided at both sides of respective ones of the plurality of discharge electrodes, and a high or low potential is applied to the auxiliary electrodes so as to cancel out an electric interaction between respective ones of the plurality of discharge electrodes.
    Type: Grant
    Filed: October 27, 1999
    Date of Patent: December 11, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Lee Chahn, Hideki Shinohara, Shigetaka Fujiwara, Shuji Imazeki, Seiji Yonekura, Yoshiharu Nagae
  • Patent number: 6286938
    Abstract: An ink jet recording apparatus has a head substrate, a jetting member disposed on the substrate, a recording electrode disposed so as to sandwich the jetting member and for making ink jet from the jetting member, and a separating wall for covering the recording electrode, wherein the ink is supplied from the proximal end of the jetting member and recovered in an upward direction from near the tip end of the jetting member. According to such an arrangement, it becomes possible to prevent the recording electrode from being clogged with ink adhering at the tip end thereof, and thus, the locus of the ink drop jetted from the head can be prevented from being deviated due to deviation of the jetting point on the jetting member. Accordingly, it becomes possible to provide an ink jet recording apparatus which is capable of printing an image with a high definition.
    Type: Grant
    Filed: February 16, 2000
    Date of Patent: September 11, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Mamoru Okano, Seiji Yonekura, Yoshinobu Fukano, Shigetaka Fujiwara, Atsushi Onose
  • Patent number: 5860049
    Abstract: By employing a developer using ferrite system carriers, a developing process can be carried out using a low brushing force by a magnetic portion having the same polarity in a developing unit in a developing roller. A relationship between a circumferential speed Up (mm/sec) of a photoconductor, a ratio K of a circumferential speed of a developing sleeve of the developing roller to the circumferential speed of the photoconductor, and a developing potential difference .DELTA.V (V) is set to 1.5.ltoreq.(K.times..DELTA.V/Up).ltoreq.2.1.
    Type: Grant
    Filed: May 27, 1997
    Date of Patent: January 12, 1999
    Assignee: Hitachi, Ltd.
    Inventors: Takao Kumasaka, Tatsuo Igawa, Shigetaka Fujiwara, Nobuyoshi Hoshi
  • Patent number: 5430528
    Abstract: In a developing apparatus in which a developer containing magnetic particles is carried on a developer carrier to form a magnetic brush and a latent image on a latent image carrier opposing the developer carrier is developed by the magnetic brush, the magnetic brush bristle height and the developing gap are controlled to keep density of a first color image and density of a second and the ensuing color images in color development at predetermined values or more, thereby maintaining quality of printed images stably. There are also provided method and apparatus of measuring the bristle height of the magnetic brush of the developing apparatus, which bristle height is a parameter indispensable for control of the above developing condition, under the dynamic condition that the developing roller rotates.
    Type: Grant
    Filed: June 29, 1990
    Date of Patent: July 4, 1995
    Assignees: Hitachi, Ltd., Hitachi Koki Co. Ltd.
    Inventors: Takao Kumasaka, Yuzuru Simazaki, Shigetaka Fujiwara, Isamu Komatsu, Youji Hirose
  • Patent number: 5023464
    Abstract: In a heat roll consisting of a mandrel and a surface layer, this invention comprises a fixing apparatus and a recording apparatus, wherein a thickness of the surface layer is formed not exceeding the thickness determined by a square root of the product of a heat diffusion rate of the surface material and a nip time required for a form to pass a nip zone, and a thickness of the mandrel is formed not less than the thickness determined by a square root of the product of a heat diffusion rate of the mandrel material and a one rotational period of the mandrel. Since the surface layer and the mandrel are so specified for the thickness as mentioned, a quantity of heat flowing from the mandrel into the surface layer multiplies, and thus a high fixing strength is obtainable. The fixing apparatus and the recording apparatus are provided further with a cleaning device high in cleaning capacity.
    Type: Grant
    Filed: September 19, 1990
    Date of Patent: June 11, 1991
    Assignees: Hitachi, Ltd., Hitachi Koki Co., Ltd.
    Inventors: Teruaki Mitsuya, Shigetaka Fujiwara, Michio Endou, Akira Terakado
  • Patent number: 4862828
    Abstract: Non-contact type developing device and method for electrophotographic recording system. The pitch of magnetic poles on a developing sleeve carrying a developer is selected to fall within a predetermined range or is varied such that the pitch increases as the circumferential distance from the point where the gap between the developer carrier member and a photosensitive member is minimum. The bias voltage applied to the developing sleeve is controlled in accordance with a change in the size of the gap between the surface of the photosensitive member and the layer of the developer on the developer carrying member. Alternatively, the bias voltage is applied throughout a period in which the charged region on the photosensitive member is opposed by the developing sleeve.
    Type: Grant
    Filed: February 23, 1988
    Date of Patent: September 5, 1989
    Assignees: Hitachi, Ltd., Hitachi Koki Co., Ltd.
    Inventors: Takao Kumasaka, Teruaki Mitsuya, Isamu Komatsu, Shigetaka Fujiwara, Yuzuru Shimazaki
  • Patent number: 4821052
    Abstract: A flash lamp apparatus for reducing occurrence of spots on a recording paper wherein an overlapping portion formed between two adjacent fusing areas of the recording paper receives a first flash and a second flash from a flash lamp so as to heat and fuse a toner on the recording paper. The overlapping portion is controlled so as to reduce occurrence of spots on the recording paper by reducing an area of the overlapping portion on a recording paper. Such reduction in the overlapping portion may be obtained by controlling a frequency of the flash or controlling a feeding velocity of the recording paper. Alternatively, the fusing energy of the overlapping portion may be reduced by changing alternately the radiating energy.
    Type: Grant
    Filed: September 29, 1987
    Date of Patent: April 11, 1989
    Assignees: Hitachi, Ltd., Hitachi Koki Co., Ltd.
    Inventors: Teruaki Mitsuya, Takao Kumasaka, Shinichi Nishino, Masato Yamada, Shigetaka Fujiwara
  • Patent number: 4767931
    Abstract: A thin film manufacturing and processing apparatus by using an ion beam comprises a plasma producing vessel for producing therein a plasma by ionizing a neutral gas, an electrode assembly for extracting ions in the form of an ion beam from the plasma, a vacuum container accomodating therein a target to be worked through irradiation of the ion beam, and permanent magnets disposed on the outer periphery of the plasma generating vessel which is formed of a nonmagnetic material and serves as an anode electrode. An ion beam of high uniformity and a large diameter can be obtained to allow manufacture and processing of large scale magnetic thin films and semiconductors with high precision.
    Type: Grant
    Filed: December 17, 1986
    Date of Patent: August 30, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Tadashi Sato, Tomoe Kurosawa, Shigetaka Fujiwara, Masaru Higaki