Patents by Inventor Takeshi Yamakawa

Takeshi Yamakawa 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: 20030091369
    Abstract: An image forming apparatus of the present invention includes an image carrier for carrying a toner image thereon while being driven to rotate. A conveyor conveys a recording medium, to which the toner image is to be transferred from the image carrier, to an image transfer position. An image carrier controller controls the linear velocity of the image carrier in rotation. A conveyance controller controls the linear velocity of the recording medium being conveyed by the conveyor. A main controller controls the image carrier controller and conveyance controller such that the mean linear velocity of the image carrier and that of the recording medium are different from each other.
    Type: Application
    Filed: December 20, 2002
    Publication date: May 15, 2003
    Inventor: Takeshi Yamakawa
  • Patent number: 6243128
    Abstract: An image forming apparatus includes a photoconductor, a light source that emits a light beam, and a scanning device that guides a light beam emitted from the light source onto a surface of the photoconductor so as to scan the surface of the photoconductor with the light beam to form a latent image thereupon. A housing, to which the light source and the scanning device are mounted, is mounted to a main body of the apparatus by a stay. The housing is supported by the stay such that an angle of a scanning direction of the light beam relative to a direction in which a surface of the photoconductor moves is adjustable so as to be at a substantially right angle and thereby an image is formed in a rectangular form by way of rotating the housing.
    Type: Grant
    Filed: February 16, 1999
    Date of Patent: June 5, 2001
    Assignee: Ricoh Company, Ltd.
    Inventor: Takeshi Yamakawa
  • Patent number: 6236418
    Abstract: An image forming apparatus and method wherein a writing device writes information of an image on a photoconductive body traveling in the sub-scanning direction to form an electrostatic latent image of the image thereupon by driving a light source to emit luminous flux, in response to an image signal corresponding to the image information, using a write clock and scanning the luminous flux from the light source with a scanning device in the main scanning direction on the photoconductive drum. The electrostatic latent image on the photoconductive body is developed by a developing device to a toner image, a transfer sheet having a size in the main scanning direction is selected by a selecting device, and the toner image on the photoconductive body is transferred by a transfer device to the selected transfer paper.
    Type: Grant
    Filed: November 15, 1999
    Date of Patent: May 22, 2001
    Assignee: Ricoh Company, Ltd.
    Inventor: Takeshi Yamakawa
  • Patent number: 6144764
    Abstract: The invention aims at recognition of a handwritten input character on-line with quite high accuracy. The method of on-line handwritten input character recognition of the invention is characterized in that ordinary strokes and transition strokes and/or start-end (s-e) strokes of a handwritten input character sampled on-line are compared with ordinary strokes and transition strokes and/or s-e strokes of dictionary's characters previously registered in a dictionary and the character corresponding to the handwritten input character is recognized on the basis of the result of the comparison. Otherwise, when the dictionary's character most similar to the input character corresponds to a preset character, the handwritten input character is identified by using characteristic features of the corresponding character.
    Type: Grant
    Filed: January 20, 1998
    Date of Patent: November 7, 2000
    Assignee: Mitsui High-tec, Inc.
    Inventors: Takeshi Yamakawa, Toyoshi Odahara, Naohiro Inagawa
  • Patent number: 6072516
    Abstract: An image forming method and apparatus use a multi-beam light source in a way that enables changes in writing density to be quickly made. A rotating mechanism that has the multi-beam light source rotates about an optical axis of a light beam from the multi-beam light source. A driving mechanism is included for driving the rotating mechanism, and a detecting mechanism is included for detecting a rotating position of the rotating mechanism. A controller controls the driving mechanism in either a reference mode or a positioning mode of operation. In the reference mode, the rotating mechanism is rotated to first position, which is determined by the detecting mechanism. In the positioning mode, the rotating mechanism is rotated to another position relative to the first position according to the reference mode.
    Type: Grant
    Filed: March 16, 1998
    Date of Patent: June 6, 2000
    Assignee: Ricoh Company, Ltd.
    Inventor: Takeshi Yamakawa
  • Patent number: 5803622
    Abstract: Servicing of an image forming device, such as a digital photocopier, is made convenient by providing an access opening exposing each of a number of prescribed serviceable components enclosed in a sealed casing. These serviceable components may include a light source scanner, lens group and beam detector. The casing bears removable cover units on the access openings. The serviceable components are located under the access openings, fixed in place by the cover units or elements attached to the cover units. Electrical switches coupled to the cover units may deactivate the components when the cover units are removed.
    Type: Grant
    Filed: May 11, 1995
    Date of Patent: September 8, 1998
    Assignee: Ricoh Company, Ltd.
    Inventors: Takashi Mama, Takeshi Yamakawa
  • Patent number: 5610651
    Abstract: A scanning time after a detection signal from a first laser beam detection sensor is inputted until a detection sensor from a second laser beam detection sensor is inputted by a counter, flip-flops, a corrected write frequency f1 is computed by a control circuit from a value T1 corresponding to the measured scanning time and a function F (T1) for computing a correction factor using the basic write frequency f0 and the value T1 above and through the equation of "f1=f0.times.F (T1)", and the write clock frequency is corrected by a clock generation circuit, thus the write clock frequency being controlled according to a change in the scanning speed.
    Type: Grant
    Filed: May 13, 1994
    Date of Patent: March 11, 1997
    Assignee: Ricoh Company, Ltd.
    Inventors: Takeshi Yamakawa, Takashi Mama, Kenichi Ono, Norio Michiie
  • Patent number: 5598279
    Abstract: An apparatus for circulating documents among a number of computer terminals in an office. The apparatus includes a device for reading images which are then stored. The image may then be read out from the storage. A controller controls the storage of the image and the reading of the image from storage. The apparatus also includes a device for forming a network system with a number of terminals so that the various terminals can read images from storage. The apparatus will automatically delete data from the storage under various conditions.
    Type: Grant
    Filed: November 2, 1994
    Date of Patent: January 28, 1997
    Assignee: Ricoh Company, Ltd.
    Inventors: Rie Ishii, Masayuki Hayashi, Takeshi Yamakawa, Hiroyuki Takahashi
  • Patent number: 5587813
    Abstract: A data transfer device for transferring data in a color digital copier, color printer or similar image forming apparatus of the type using a plurality of different kinds of data. A sending unit assigns other data to a predetermined number of bits of multilevel data to thereby send a plurality of kinds of data over common data lines. A receiving unit receives and separates the plurality of kinds of data. The device reduces the number of signal lines required for data transfer when a plurality of different kinds of data are not transferred at the same time.
    Type: Grant
    Filed: July 29, 1993
    Date of Patent: December 24, 1996
    Assignee: Ricoh Company, Ltd.
    Inventors: Shuichi Yamazaki, Takashi Mama, Nobuyuki Sato, Takeshi Yamakawa, Shinji Kobayashi, Yoshio Kaneko, Koji Oshikiri
  • Patent number: 5506795
    Abstract: In order to provide an apparatus and method generating chaotically behaving signals or data, a plurality of delay elements 10 to 14 are connected in series, and an output of the foremost delay element 10 is supplied to a nonlinear function element 30, while outputs of the other delay elements 11 to 14 are supplied to coefficient elements 41 to 44, respectively. The outputs of the nonlinear function element 30 and coefficient elements 41 to 44 are summed at an adding element 50, and the resultant sum is fedback to the foremost delay element 10. Initializing elements 20 to 24 release their respective initial values at one time to thereby initiate the operation. At an appropriate period of time .DELTA.t, the delay, nonlinear operation, coefficient multiplication, and addition are repeated.
    Type: Grant
    Filed: February 18, 1993
    Date of Patent: April 9, 1996
    Inventor: Takeshi Yamakawa
  • Patent number: 5382129
    Abstract: A sheet feed device incorporated in a copier, facsimile transceiver, printer or similar image forming apparatus and capable of automatically removing a wrapping from a sheet pack inserted in the apparatus and then feeding sheets one by one.
    Type: Grant
    Filed: January 15, 1993
    Date of Patent: January 17, 1995
    Assignee: Ricoh Company, Ltd.
    Inventors: Tomohito Shimizu, Hiroshi Mori, Yoshinobu Kagami, Takeshi Yamakawa, Susumu Shiina, Keisuke Hayashi
  • Patent number: 5347615
    Abstract: Applicable rules (IF-THEN rules) are generated with use of predetermined membership functions concerning input and output variables in response to entry of input and output values. Accordingly, time and labor required to make rules can be simplified. In addition, it can be also verified, by making fuzzy inferences according to the generated rules, whether or not the rules are appropriate.
    Type: Grant
    Filed: June 18, 1993
    Date of Patent: September 13, 1994
    Assignee: Omron Tateisi Electronics Co.
    Inventors: Takeshi Yamakawa, Tsutomu Ishida
  • Patent number: 5341323
    Abstract: A programmable multi-membership function circuit comprises at least one or preferably two Z function circuits, at least one or preferably two S function circuits, and a fuzzy logic circuit for calculating fuzzy logic from the output of the Z function circuits and the output of the S function circuits. The fuzzy logic circuit comprises a MIN (intersection) circuit and a MAX (union) circuit, or the combination of these circuits.
    Type: Grant
    Filed: December 2, 1991
    Date of Patent: August 23, 1994
    Assignee: Omron Tateisi Electronics Co.
    Inventor: Takeshi Yamakawa
  • Patent number: 5295226
    Abstract: A fuzzy computer which carries out fuzzy operations using membership functions. This fuzzy computer readily processes implications made up of an antecedent expressed by fuzzy values and a consequent expressed by singleton values. This fuzzy computer includes a fuzzy processor, fuzzy controller and a MAX circuit block composite device used in same, and in addition, it contains grade-controllable membership function circuits, grade-controllable membership function generator circuits and center of gravity determination circuits which function as a useful circuit called a defuzzifier for converting fuzzy quantities to definitive values.
    Type: Grant
    Filed: September 2, 1992
    Date of Patent: March 15, 1994
    Assignee: Research Development Corporation of Japan
    Inventor: Takeshi Yamakawa
  • Patent number: 5239620
    Abstract: Applicable rules (IF-THEN rules) are generated with use of predetermined membership functions concerning input and values. Whether the rules are appropriate is verified by making fuzzy inferences according to the generated rules with at least one of the rules temporarily excluded.
    Type: Grant
    Filed: August 6, 1992
    Date of Patent: August 24, 1993
    Assignee: Omron Tateisi Electronics Co.
    Inventors: Takeshi Yamakawa, Tsutomu Ishida
  • Patent number: 5227993
    Abstract: A multivalued Arithmetic Logic Unit (ALU) is composed of a multivalued signal source, a memory array, a selection array, an AND array and an output circuit. The multivalued signal source generates signals each of which represents a logic value of multivalued logic. The memory array is provided with an address line group for each and every function to be inplemented, each address line group comprising a number of address lines. Which multivalued logic signals will appear on the address lines of each address line group depends upon a program based on the truth table of the corresponding function. Any one of the plural address line groups is selected by the selection array, to which a signal designating the function to be implemented is applied. One address line in the selected address line group is selected by the AND array, which has an input signal applied thereto, and the logic value signal on the selected line is delivered via the output circuit.
    Type: Grant
    Filed: March 5, 1991
    Date of Patent: July 13, 1993
    Assignee: Omron Tateisi Electronics Co.
    Inventor: Takeshi Yamakawa
  • Patent number: 5189728
    Abstract: Applicable rules (IF-THEN rules) are generated with use of predetermined membership functions concerning input and output variables in response to entry of input and output values. Accordingly, time and labor required to make rules can be simplified. In addition, it can be also verified, by making fuzzy inferences according to the generated rules, whether or not the rules are appropriate.
    Type: Grant
    Filed: October 8, 1991
    Date of Patent: February 23, 1993
    Assignee: Omron Tateisi Electronics Co.
    Inventors: Takeshi Yamakawa, Tsutomu Ishida
  • Patent number: 5167005
    Abstract: A fuzzy computer which carries out fuzzy operations using membership functions.This fuzzy computer readily processes implications made up of an antecedent expressed by fuzzy values and a consequent expressed by singleton values.This fuzzy computer includes a fuzzy processor, fuzzy controller and a MAX circuit block composite device used in same, and in addition, it contains grade-controllable membership function circuits, grade-controllable membership function generator circuits and center of gravity determination circuits which function as a useful circuit called a defuzzifier for converting fuzzy quantities to definitive values.
    Type: Grant
    Filed: August 11, 1989
    Date of Patent: November 24, 1992
    Assignee: Research Development Corporation of Japan
    Inventor: Takeshi Yamakawa
  • Patent number: 5113366
    Abstract: A programmable multi-membership function circuit comprises at least one or preferably two Z function circuits, at least one or preferably two S function circuits, and a fuzzy logic circuit for calculating fuzzy logic from the output of the Z function circuits and the output of the S function circuits. The fuzzy logic circuit comprises a MIN (intersection) circuit and a MAX (union) circuit, or the combination of these circuits.
    Type: Grant
    Filed: March 14, 1989
    Date of Patent: May 12, 1992
    Assignee: Omron Tateisi Electronics Co.
    Inventor: Takeshi Yamakawa
  • Patent number: 5019867
    Abstract: An electrophotographic copier or similar image forming apparatus having a photoconductive drum and a developing unit having a developing roller which is pressed against the drum. The developing unit is removably mounted on a body of the apparatus and arranged such that reaction forces exerted in the vertical direction by the copier body on the developing unit are directed upward at all times. When the pressing contact of the developing roller with the drum is cancelled, the developing unit is held in a retracted position where it is spaced apart from the drum.
    Type: Grant
    Filed: August 25, 1989
    Date of Patent: May 28, 1991
    Assignee: Ricoh Company, Ltd.
    Inventors: Takeshi Yamakawa, Misao Tanzawa