Patents by Inventor Hisao Okada

Hisao Okada 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: 6172663
    Abstract: A driver circuit for driving a capacitive load has a first electrode and a second electrode. The driver circuit includes: a first charging section, connected with the first electrode, for applying a charge to the first electrode during a. first period and receiving a charge from the first electrode during a second period; a second charging section, connected with the second electrode, for receiving a charge from the second electrode during the first period and applying a charge to the second electrode during the second period; a first section for prohibiting a movement of a charge between the first charging section and the first electrode during a third period between the first period and the second period; a second section for prohibiting a movement of a charge between the second charging section and the second electrode during the third period; and a third section for allowing a movement of a charge between the first electrode and the second electrode during a fourth period included in the third period.
    Type: Grant
    Filed: March 11, 1996
    Date of Patent: January 9, 2001
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hisao Okada, Yuji Yamamoto, Sunao Etou
  • Patent number: 6131000
    Abstract: An electrophotographic printing apparatus using electric potential dividing development processing without the occurrence of primary fringe and fringe caused by auxiliary exposure has reverse electric fields causing primary fringe and fringe caused by auxiliary exposure adjusted to be nearly equal to each other. The auxiliary exposure is applied to an area surrounding one image, and an electric potential of an intermediate electric potential zone is brought close to a bias electric potential of another image which is not subjected to auxiliary exposure.
    Type: Grant
    Filed: December 10, 1998
    Date of Patent: October 10, 2000
    Assignees: Hitachi, Ltd., Hitachi Koki Co., Ltd.
    Inventors: Shinichi Akatsu, Teruaki Mitsuya, Kenichi Ito, Nobuyoshi Hoshi, Ryuuichi Shimizu, Hisao Okada, Hiroyuki Mabuchi, Masayoshi Ishii, Seiji Maruo
  • Patent number: 6118421
    Abstract: A method for driving a liquid crystal panel including a plurality of pixel electrodes arranged in a matrix, a plurality of data lines respectively connected to the pixel electrodes in a plurality of columns, a plurality of gate lines respectively connected to the pixel electrodes in a plurality of rows, and a plurality of switching devices, respectively connected to the pixel electrodes, for connecting and disconnecting the corresponding pixel electrode and the corresponding data line based on a signal sent from the corresponding gate line. The method includes the step of applying a driving voltage having a waveform corresponding to image data used for display to each data line while inverting the driving voltage gate line by gate line and frame by frame, so as to maintain an average value of the driving voltage in each frame within a certain range.
    Type: Grant
    Filed: September 27, 1996
    Date of Patent: September 12, 2000
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takafumi Kawaguchi, Toshihiro Yanagi, Makoto Takeda, Hisao Okada
  • Patent number: 6061534
    Abstract: In a two-color image forming apparatus, correction exposure of creating an area having a potential between an image area potential and a white area potential is made for a decided white area on the periphery of the image area. A potential difference between the image area and white area is reduced to attenuate an edge effect, thereby preventing the fringe development. This is accomplished by varying the light amount for the white areas of the intermediate potential areas as a function of the following: surface potentials measured, change in the developing bias voltage and rotating speed of a developing roll, adjustment of the amount of toners by a toner sensor, changing the resistance of a developer, and/or development of raster image processing.
    Type: Grant
    Filed: September 22, 1998
    Date of Patent: May 9, 2000
    Assignee: Hitachi Koki Co., Ltd.
    Inventors: Hisao Okada, Teruaki Mitsuya, Shinichi Akatsu
  • Patent number: 5986648
    Abstract: The display driving device of the invention has a display driver for driving a display device by using image data to perform a display. The display driving device includes: a time-series data generating section for arranging division data obtained by dividing the image data in a time-series manner, to generate time-series data; and transmission lines provided between the time-series data generating section and the display driver through which the time-series data is transmitted from the time-series data generating section. When the display area of the display device is divided into a plurality of display areas, a plurality of display drivers are provided.
    Type: Grant
    Filed: December 19, 1997
    Date of Patent: November 16, 1999
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hisao Okada, Yuji Yamamoto, Takeshi Takarada
  • Patent number: 5929847
    Abstract: A drive circuit for a display device supplying a plurality of gray-scale voltages to the display device, based on externally supplied digital video signal data, includes: a plurality of gray-scale power supplies, a plurality of drive power supplies, a unit for forming a first part of the plurality of gray-scale voltages using the gray-scale voltage power supplies, and a unit for forming a second part of the plurality of gray-scale voltages using the drive power supplies.
    Type: Grant
    Filed: February 9, 1994
    Date of Patent: July 27, 1999
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Toshihiro Yanagi, Hisao Okada, Tadatsugu Nishitani, Yuji Yamamoto, Takeshi Takarada
  • Patent number: 5923933
    Abstract: A uniform image is obtained by matching the sliding friction force, the moving speed and the developing agent in a developing region of two developing rollers and an electric characteristic of a photosensitive body used for image development. Two developing rollers rotating in directions opposite to each other are used, the moving direction of the first developing roller being opposite to the moving direction of the photosensitive body, and a circumferential speed ratio of a circumferential speed of the first developing roller to a circumferential speed of the photosensitive body is within a rage of 0.5 to 2.5; and the moving direction of the second developing roller is equal to the moving direction of the photosensitive body, and a circumferential speed ratio of a circumferential speed of the second developing roller to a circumferential speed of the photosensitive body is within a range of 1.5 to 3.5.
    Type: Grant
    Filed: February 13, 1998
    Date of Patent: July 13, 1999
    Assignee: Hitachi Koki Co., Ltd.
    Inventors: Masayasu Anzai, Tsuneaki Kawanishi, Yoshitaka Fujinuma, Hiroyoshi Matsumoto, Yasuo Takuma, Hisao Okada, Masayuki Ainoya, Takashi Suzuki, Yuichiro Suzuki, Tomonari Hokkyo, Koji Kato, Katsuya Kawai, Tsutomu Nakagawa
  • Patent number: 5923312
    Abstract: A driving circuit used in a display apparatus includes a plurality of output circuits for selecting two reference gradation voltages among a plurality of different reference gradation voltages based on display data and outputting an interpolation voltage corresponding to the display data using the two reference gradation voltages; and a plurality of supply lines for supplying the plurality of reference gradation voltages. The supply lines including a plurality of voltage supply lines and a plurality of signal supply lines. One of the plurality of voltage supply lines supplies a voltage having a minimum difference from the voltage of a common electrode of the display apparatus and another of the plurality of voltage supply lines supplies a voltage having a maximum difference from the voltage of the common electrode. The two reference gradation voltages selected by each of the output circuits are supplied by one of a plurality of pairs of supply lines.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: July 13, 1999
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hisao Okada, Yuji Yamamoto, Sunao Etou, Kuniaki Tanaka
  • Patent number: 5907755
    Abstract: A predetermined mathematical formula, which defines an occurrence degree of an image defect where the toner layer is thinned or no toner image is formed, is set up, which is valid for a developing device including a reverse turn developer carrier and a forward turn developer carrier. A difference between the total sum A of the values by the above formula showing the occurrence degree of the image defect on the forward turn developing roller and the total sum B of the values by the above formula showing the occurrence degree on the reverse turn developing roller, i.e., (A-B), is selected within a range of -0.56 to +0.5.
    Type: Grant
    Filed: May 7, 1998
    Date of Patent: May 25, 1999
    Assignee: Hitachi Koki Co., Ltd.
    Inventors: Yasuo Takuma, Yoshitaka Fujinuma, Masayasu Anzai, Hisao Okada
  • Patent number: 5884119
    Abstract: In the tri-level process in which positive and negative latent images are formed on a photosensitive body and then developed using toners of two colors (for example, red and black) charged respectively to opposite polarities with respect to the polarities of the latent images, there has been a problem of degrading the quality of a two-color picture by the appearance of a special phenomenon in which red toner is attached around a black image and black toner is attached around a red image by attraction of the reverse electric field. An exposure control is performed in order to suppress the fringe phenomenon.
    Type: Grant
    Filed: July 16, 1997
    Date of Patent: March 16, 1999
    Assignees: Hitachi, Ltd., Hitachi Koki Co., Ltd.
    Inventors: Seiji Maruo, Hisao Okada, Hiroyuki Mabuchi, Kazutoshi Obara, Kenichi Ito
  • Patent number: 5784041
    Abstract: The driving circuit of this invention for a display device for displaying a plurality of gray levels in accordance with digital data including a first bit portion and a second bit portion includes: a first voltage dividing circuit for dividing a plurality of gray level voltages so as to generate a plurality of first interpolation voltages between the plurality of gray level voltages; a first selection circuit for selecting a first voltage and a second voltage different from the first voltage among the plurality of gray level voltages and the plurality of first interpolation voltages in accordance with the first bit portion of the digital data; a second voltage dividing circuit for dividing the first voltage and the second voltage so as to generate a plurality of second interpolation voltages between the first voltage and the second voltage; and a second selection circuit for selecting one voltage among at least one of the first voltage and the second voltage and the plurality of second interpolation voltages.
    Type: Grant
    Filed: March 20, 1997
    Date of Patent: July 21, 1998
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hisao Okada, Sunao Eto, Mikio Hashimoto
  • Patent number: 5745818
    Abstract: An image formation method for forming an image of a plurality of colors through a charging step, an image exposing step, a developing step and a transferring step, wherein the image exposing step is made up of a first image exposing step and a second image exposing step, the developing step of at least one color is carried out after the first image exposing step, and in the subsequent second image exposing step, the toner image area formed by the developing step is exposed and charge latent images for forming toner images of the rest of the colors are formed while a potential of the toner image area is selectively shifted.
    Type: Grant
    Filed: March 17, 1994
    Date of Patent: April 28, 1998
    Assignees: Hitachi, Ltd., Hitachi Koki Co., Ltd.
    Inventors: Takao Kumasaka, Hisao Okada, Noboru Tokuyasu, Yuzuru Simazaki, Susumu Tateyama
  • Patent number: 5734378
    Abstract: The display driving device of the invention has a display driver for driving a display device by using image data to perform a display. The display driving device includes: a time-series data generating section for arranging division data obtained by dividing the image data in a time-series manner, to generate time-series data; and transmission lines provided between the time-series data generating section and the display driver through which the time-series data is transmitted from the time-series data generating section. When the display area of the display device is divided into a plurality of display areas, a plurality of display drivers are provided.
    Type: Grant
    Filed: October 21, 1994
    Date of Patent: March 31, 1998
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hisao Okada, Yuji Yamamoto, Takeshi Takarada
  • Patent number: 5686933
    Abstract: In a drive circuit for a display apparatus into which a digital video signal is input and in which a plurality of parallel signal electrodes are provided, one of signal voltages having different levels is output in accordance with the digital video signal, or two adjacent ones of said signal voltages are simultaneously output. Alternatively, one of the signal voltages is supplied to a signal electrode in one portion of one output period, and another one of the signal voltages is supplied to the signal electrode in another portion of the output period. The length ratio of the two portions of one output period is appropriately determined according to a digital video signal, whereby an arbitrary voltage corresponding to the video signal data can be applied to the pixel.
    Type: Grant
    Filed: October 3, 1994
    Date of Patent: November 11, 1997
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hisao Okada, Shigeyuki Uehira, Katumi Miki, Kuniaki Tanaka, Toshihiro Yanagi
  • Patent number: 5680148
    Abstract: A driving circuit for a display apparatus is provided which apparatus includes pixels allowed to produce a display image by specific voltages applied thereto. The driving circuit includes: a first voltage output means for generating an interpolated voltage on the basis of gray-scale reference voltages supplied thereto, and applying the interpolated voltage to the pixels, the interpolated voltage being of a level between the voltage levels of the gray-scale reference voltages; and a second voltage output means for applying, to the pixels, a voltage different from the gray-scale reference voltages.
    Type: Grant
    Filed: July 17, 1995
    Date of Patent: October 21, 1997
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hisao Okada, Tadatsugu Nishitani, Toshihiro Yanagi
  • Patent number: 5673061
    Abstract: A driving circuit of the invention is used for driving a display apparatus which includes pixels and data lines for applying voltages to the pixels and which displays an image with multiple gray scales in accordance with video data consisting of a plurality of bits.
    Type: Grant
    Filed: September 9, 1996
    Date of Patent: September 30, 1997
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hisao Okada, Yuji Yamamoto, Mitsuyoshi Seo, Kuniaki Tanaka
  • Patent number: 5642126
    Abstract: A method for driving a display apparatus is provided which apparatus includes a display section having pixels and switching elements respectively connected to the pixels, and also includes a data driver for driving the display section, and data lines connecting the switching elements to the data driver, the pixels being allowed to produce a display image by specific voltages applied thereto. The method includes the steps of: allowing the data driver to output a non-oscillating voltage signal to each of the data lines during a predetermined time period from the start of one output period; and allowing the data driver to output an oscillating voltage signal to each of the data lines from the end of the predetermined time period until the end of the output period, the oscillating voltage signal including at least one oscillating component.
    Type: Grant
    Filed: October 16, 1995
    Date of Patent: June 24, 1997
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hisao Okada, Shigeyuki Uehira, Junji Kawanishi
  • Patent number: 5635950
    Abstract: In a drive circuit for a display apparatus into which a digital video signal is input and in which a plurality of parallel signal electrodes are provided, one of signal voltages having different levels is output in accordance with the digital video signal, or two adjacent ones of said signal voltages are simultaneously output. Alternatively, one of the signal voltages is supplied to a signal electrode in one portion of one output period, and another one of the signal voltages is supplied to the signal electrode in another portion of the output period. The length ratio of the two portions of one output period is appropriately determined according to the digital video signal, whereby an arbitrary voltage corresponding to the video signal data can be applied to the pixel.
    Type: Grant
    Filed: April 5, 1995
    Date of Patent: June 3, 1997
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hisao Okada, Shigeyuki Uehira, Katumi Miki, Kuniaki Tanaka, Toshihiro Yanagi
  • Patent number: 5623278
    Abstract: In a drive circuit for a display apparatus into which a digital video signal is input and in which a plurality of parallel signal electrodes are provided, one of signal voltages having different levels is output in accordance with the digital video signal, or two adjacent ones of said signal voltages are simultaneously output. Alternatively, one of the signal voltages is supplied to a signal electrode in one portion of one output period, and another one of the signal voltages is supplied to the signal electrode in another portion of the output period. The length ratio of the two portions of one output period is appropriately determined according to a digital video signal, whereby an arbitrary voltage corresponding to the video signal data can be applied to the pixel.
    Type: Grant
    Filed: April 5, 1995
    Date of Patent: April 22, 1997
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hisao Okada, Shigeyuki Uehira, Katumi Miki, Kuniaki Tanaka, Toshihiro Yanagi
  • Patent number: 5621439
    Abstract: A voltage compensation circuit supplies a desired voltage to a portion to which the desired voltage is to be supplied, by compensating for voltage drops caused by line resistances of voltage supply lines. The voltage compensation circuit includes: a first voltage supply line having a first end; and a second voltage supply line having a second end. In the voltage compensation circuit, a first voltage which is higher than the desired voltage by a predetermined value is applied to the first end, and a second voltage which is lower than the desired voltage by the predetermined value is applied to the second end. The portion to which the desired voltage is to be supplied is connected to the first voltage supply line at a first junction, and the portion to which the desired voltage is to be supplied is connected to the second voltage supply line at a second junction.
    Type: Grant
    Filed: July 6, 1994
    Date of Patent: April 15, 1997
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hisao Okada, Yuji Yamamoto, Shigeyuki Uehira