Patents by Inventor Kazuhiro Yuasa

Kazuhiro Yuasa 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: 5486909
    Abstract: A developing device for an image forming apparatus and having a relatively hard first developing roller formed with fine N-S magnetic poles on the periphery thereof, and a relatively soft second developing roller for conveying toner electrostatically transferred thereto from the first roller toward a photoconductive drum. The toner is charged by friction while being passed through between the first roller and a blade, and then magnetically deposited on the first roller. At a position where the first and second rollers contact each other, the adequately charged toner is substantially evenly charged by friction and electrostatically transferred from the first roller to the second roller. The second roller conveys the toner toward the drum. The second roller has a surface roughness whose ratio to the mean particle size of the toner is selected to be less than or equal to 1.5.
    Type: Grant
    Filed: May 11, 1995
    Date of Patent: January 23, 1996
    Assignee: Ricoh Company, Ltd.
    Inventors: Eiji Takenaka, Kazuhiro Yuasa, Shuichi Endoh, Iwao Matsumae, Yoshiaki Tanaka, Hiroshi Hosokawa, Mugijiroh Uno, Hiroshi Saitoh, Toshihiro Sugiyama, Tetsuo Yamanaka, Eisaku Murakami, Satoru Komatsubara
  • Patent number: 5386301
    Abstract: An image processing apparatus includes a reading part for reading an image by raster scanning of a document and for producing a multilevel image data relating to one pixel of the image, a memory part for storing a plurality of predetermined weight matrix patterns, each weight matrix pattern having N.times.N weight coefficients arranged in an N.times.
    Type: Grant
    Filed: August 18, 1993
    Date of Patent: January 31, 1995
    Assignee: Ricoh Company, Ltd.
    Inventors: Kazuhiro Yuasa, Kazumasa Koike
  • Patent number: 5255061
    Abstract: An image forming apparatus, which forms a predetermined image on each recording paper of a plurality of recording papers and ejects each recording paper therefrom through a feed path, includes a body and a first lid. The first lid is pivotably provided on the body so as to pivot from a closing position to an opening position, and the feed path is mostly exposed when the first lid is located at the opening position. The body includes photosensitive member, a latent image forming device, and a developing device, whereas the first lid includes merely a transfer device so that the first lid is light enough to be opened easily. In addition, a jammed paper can be removed easily from the feed path because the feed path is mostly exposed when the first lid is located at the opening position.
    Type: Grant
    Filed: November 30, 1990
    Date of Patent: October 19, 1993
    Assignee: Ricoh Company, Ltd.
    Inventors: Yozo Matsuura, Shiroh Kondoh, Kazuhiro Yuasa
  • Patent number: 5126799
    Abstract: A xerographic image recording apparatus includes a photosensitive body moved along a circuitous path, an electric discharging unit for eliminating electric charges from the photosensitive body, a precharging unit for charging the photosensitive body electrically, an image writing unit for writing an image on the photosensitive body, an image developing unit for coating the photosensitive body by the toner to form a toner image on the photosensitive body, a recording sheet feeding unit for feeding a recording sheet along a sheet path, an image transfer unit for transferring the toner image onto a recording sheet, a cleaning unit for removing the toner remaining on the photosensitive body after the transfer of image on the recording sheet is completed, a toner supply tank for supplying the toner to the image developing unit, and a toner recovery tank for collecting the toner removed by the cleaning unit from the photosensitive body, wherein the toner supply tank and the toner recovery tank are assembled into a
    Type: Grant
    Filed: November 29, 1990
    Date of Patent: June 30, 1992
    Assignee: Ricoh Company, Ltd.
    Inventors: Yozo Matsuura, Shiroh Kondoh, Kazuhiro Yuasa, Hiroshi Saitoh, Hiroyuki Kiyoi, Masanori Yoshimura, Masahiro Kawabe, Yoshiya Itoh
  • Patent number: 5111251
    Abstract: A cleaning apparatus for cleaning a photoconductive belt of a seamless type which is used within a recording system for transferring a latent image of information to be recorded to a recording paper, the photoconductive belt being rotated along a rotation path by a plurality of supporting rollers. The cleaning apparatus includes a blade part provided at a first position along the rotation path of the photoconductive belt for removing a residual toner from the photoconductive belt, a brush part provided at a second position upstream of the first position along the rotation path of the photoconductive belt, the brush part having a pile material coming in contact with a surface of the photoconductive belt, and a scraper part for cleaning the brush part by removing a remaining toner from the pile material of the brush part. It is thus possible to keep the photoconductive belt clean for a long duration of the use in the recording system, without causing a cleaning problem.
    Type: Grant
    Filed: November 9, 1990
    Date of Patent: May 5, 1992
    Assignee: Ricoh Company, Ltd.
    Inventors: Mugijirou Uno, Kazuhiro Yuasa
  • Patent number: 4757332
    Abstract: A recording apparatus for forming a toner image with simultaneous application of a light image and toner is provided. An endless imaging belt includes a transparent substrate, an inner conductive layer formed on the substrate, a photoconductive layer formed on the inner conductive layer, an outer conductive layer formed on the photoconductive layer, and a surface layer formed on the outer conductive layer. With a positive bias applied to the outer conductive layer and a negative bias to the inner conductive layer, a light image is applied to the imaging member from the transparent substrate side and at the same time a film of positively charged toner is applied to the opposite side of the imaging member, so that a toner image is directly formed on the imaging member by selective deposition of toner according to a light pattern of the light image.
    Type: Grant
    Filed: July 8, 1986
    Date of Patent: July 12, 1988
    Assignee: Ricoh Company, Ltd.
    Inventor: Kazuhiro Yuasa
  • Patent number: 4641955
    Abstract: A recording apparatus for use with a copier, a printer or the like which utilizes an ion projection recording system for recording images on plain papers. Toner is carried by toner transport means and charged to a first polarity, while a transfer member is fed by feeding means to make contact with or come close to the toner layer on the transport means. Ion generating means is located at the opposite side to the charged toner layer with respect to the transfer member and generates ions having a second polarity which is opposite to the polarity of the toner or having both a polarity common to that of the toner and a second polarity opposite to the same. The streams of ions are controlled pixel by pixel by ion stream control means responsive to image data which should be recorded, so that the toner particles are selectively deposited on the transfer member by Coulomb's force which acts between the ions and the charged toner.
    Type: Grant
    Filed: November 5, 1985
    Date of Patent: February 10, 1987
    Assignee: Ricoh Company, Ltd.
    Inventor: Kazuhiro Yuasa
  • Patent number: 4637708
    Abstract: A one-component high-resistance toner is transferred from a rotatable sleeve, or first transport member, to an endless belt, or second transport member. An electric field having a predetermined intensity is developed between the sleeve and the belt in a direction for transferring the toner from the former to the latter. Toner particles charged to a polarity opposite to a desired polarity are prevented from moving from the sleeve toward the belt.
    Type: Grant
    Filed: July 24, 1985
    Date of Patent: January 20, 1987
    Assignee: Ricoh Company, Ltd.
    Inventor: Kazuhiro Yuasa
  • Patent number: 4636815
    Abstract: An electrostatic recording apparatus includes an endless belt of dielectric material which is supported by a plurality of rollers to move along a predetermined path. A charger is provided to uniformly charge both sides of the belt in opposite polarities. A thermal printhead is provided at one side of the belt to apply a heat pattern in accordance with an image signal to have the charge selectively discharged on either side to define an electrostatic latent image. A developing unit is provided at the opposite side of the belt for developing the latent image by applying toner thereto. Such an arrangement in which the thermal printhead and the developing unit are provided opposite sides with respect to the belt is particularly advantageous.
    Type: Grant
    Filed: October 5, 1984
    Date of Patent: January 13, 1987
    Assignee: Ricoh Company Ltd.
    Inventor: Kazuhiro Yuasa
  • Patent number: 4621274
    Abstract: A method of cleaning the record head of an image recording system of the transfer type including an electrostatic record head having a multiplicity of electrodes arranged in an array or arrays and a preliminary charging unit operative to uniformly charge a dielectric record medium to a predetermined pre-charge voltage before the record medium is to be passed to the record medium for being activated to produce electrostatic latent images thereon by selective application of control signals to the electrodes in addition to a predetermined recording bias voltage lower than the pre-charge voltage and constantly impressed on all of the electrodes throughout each page print cycle of the system. The method comprises applying a cleaning voltage to the electrodes during a period of time continuous to one of the page print cycles, the cleaning voltage being higher than the pre-charge voltage.
    Type: Grant
    Filed: October 1, 1984
    Date of Patent: November 4, 1986
    Assignee: Ricoh Company, Ltd.
    Inventor: Kazuhiro Yuasa
  • Patent number: 4586807
    Abstract: An electrostatic recording method for first forming a developed image on an endless imaging belt and then transferring the developed image to a transfer medium is provided. The endless imaging belt includes an excessively high resistance region in the vicinity of its seam and the image transfer step is held inoperative at least while this region is moving through a developing station.
    Type: Grant
    Filed: March 19, 1984
    Date of Patent: May 6, 1986
    Assignee: Ricoh Company, Ltd.
    Inventor: Kazuhiro Yuasa
  • Patent number: 4567495
    Abstract: A record head of an image recording apparatus is reciprocally tilted to suitably vary the contact condition between the surface of the record head and that of a recording medium, thereby removing toner particles which are momentarily stuck to the record head surface. To maintain styluses of the head unchanged in position, the reciprocation of the record head is effected for the interval between the end of a recording cycle for one page and the start of the next recording cycle for another page, which interval has no influence on the image recording operation.
    Type: Grant
    Filed: March 21, 1983
    Date of Patent: January 28, 1986
    Assignee: Ricoh Company, Ltd.
    Inventors: Kazuhiro Yuasa, Kenya Komada
  • Patent number: 4539600
    Abstract: An image signal processing apparatus particularly suitable for use in a facsimile system for converting an analog image signal obtained by photoelectrically reading an original into a binary image signal for further processing is provided. The present image signal processing apparatus comprises a digital-to-analog converter and a digital data input unit, preferably a microcomputer, connected to the converter. Thus, the level of the reference voltage to be supplied to the comparator for converting the analog image signal into the binary image signal may be finely adjusted appropriately without complication in structure.
    Type: Grant
    Filed: August 28, 1981
    Date of Patent: September 3, 1985
    Assignee: Ricoh Company, Ltd.
    Inventors: Shuichi Takahashi, Mitsuru Kondo, Kazuhiro Yuasa
  • Patent number: 4537491
    Abstract: A development apparatus for developing latent electrostatic images to visible or transferable images of high quality for use in electrophotographic copying apparatus, electrostatic recording apparatus, facsimile apparatus or other recording apparatus, in which a development roller is in arc-contact with a latent-electrostatic-image-bearing flexible recording medium and is capable of supplying a sufficient amount of toner to the recording medium for development of the latent electrostatic images, without requiring any delicate adjustment of the gap between the development roller and the recording medium or of the gap between the development roller and a doctor blade for regulating the thickness of a toner layer on the development roller, and without increasing the rotary speed of the development roller to conventional speeds, and the doctor blade is also capable of performing charge injection to the toner with high efficiency, whereby images can be developed with high quality with a minimum deposition of toner
    Type: Grant
    Filed: October 13, 1982
    Date of Patent: August 27, 1985
    Assignee: Ricoh Company, Ltd.
    Inventors: Kenya Komada, Kazuhiro Yuasa, Shiroh Kondoh
  • Patent number: 4496987
    Abstract: An image signal processing system for converting an analog image signal into a digital or binary image signal, capable of representing half-tone or gray scale when the corresponding visual image is reproduced by a dot-matrix type printer, is provided. The present system includes storing means for storing at least an array of thresholds, at least one of the thresholds being different in level from the other to form an array pattern. Such a threshold array is used as a reference level in producing a binary image signal. Half-tone is represented by the degree of black dot density per unit area.
    Type: Grant
    Filed: October 2, 1981
    Date of Patent: January 29, 1985
    Assignee: Ricoh Company, Ltd.
    Inventors: Kazuhiro Yuasa, Shuichi Takahashi, Mitsuru Kondo
  • Patent number: 4483611
    Abstract: A magnetic cleaning device for cleaning a surface to be cleaned by removing magnetic particles therefrom includes a rotatable sleeve of a nonmagnetic material on the outer peripheral surface of which is planted a plurality of fibers to form a fur brush, a plurality of magnets disposed inside of and along the inner peripheral surface of the sleeve, a rotatable magnetic roll disposed adjacent to the sleeve for having the magnetic particles transferred from the sleeve to the roll, and a collection unit including a scraper to scrape the transferred particles off the roll.
    Type: Grant
    Filed: January 20, 1983
    Date of Patent: November 20, 1984
    Assignee: Ricoh Company, Ltd.
    Inventors: Yozo Matsuura, Kazuhiro Yuasa
  • Patent number: 4456365
    Abstract: An improved corona charging device for uniformly charging an image bearing or forming member is provided. The charging device includes a corona wire, a conductive shield partly surrounding the wire and a high voltage source connected to the wire. The voltage source includes a first voltage source for applying an A.C. voltage to the wire and a second voltage source for applying a D.C. voltage to the wire as a bias. The present charging device charges the member uniformly to a desired level at all times irrespective of the potential condition of the member prior thereto.
    Type: Grant
    Filed: August 6, 1982
    Date of Patent: June 26, 1984
    Assignee: Ricoh Company, Ltd.
    Inventor: Kazuhiro Yuasa
  • Patent number: 4447821
    Abstract: A method and apparatus for forming an electrostatic latent image free of phantoms is provided. A recording medium is first uniformly charged and the charges are selectively dissipated by the recording unit including a plurality of styluses to which a recording potential is selectively applied and auxiliary electrodes to which an auxiliary potential is applied to form an electrostatic latent image on the medium. The present invention is characterized by applying a bias potential, preferably equal to or substantially equal to the surface potential of the charged medium, to the styluses and auxiliary electrodes thereby allowing to prevent unwanted recording from occurring.
    Type: Grant
    Filed: July 16, 1982
    Date of Patent: May 8, 1984
    Assignee: Ricoh Company, Ltd.
    Inventors: Kazuhiro Yuasa, Noboru Furukawa