Patents by Inventor Takanobu Yamada

Takanobu Yamada 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: 6522843
    Abstract: When it is judged that a sheet S is not an ordinary paper but a thick paper or an OHP film sheet, or that the arrival of the sheet S at a pair of timing rollers 48 is delayed due to a slip for example beyond an allowable period of time, a controller 70 judges that a condition for transferring or fixing an image on the sheet S is not met. As a result, a secondary transfer roller 34 and a cleaner 38 are retreated from an intermediate transfer belt 12, and in this state, the intermediate transfer belt 12 carrying a toner image I thereon is made idle at least about one revolution without transferring the image I.
    Type: Grant
    Filed: June 13, 2001
    Date of Patent: February 18, 2003
    Assignee: Minolta Co., Ltd.
    Inventors: Takanobu Yamada, Seiichi Munemori, Yuusuke Morikami
  • Patent number: 6519438
    Abstract: A color image forming apparatus in accordance with the present invention including an intermediate transfer member having a movable surface. The apparatus also includes plural image forming units for forming toner images on the intermediate transfer member at each of image-forming positions, and a transfer roller for transferring the toner images formed on the intermediate transfer member onto a sheet, the transfer roller having a circumferential length equal to the distance between the adjacent image forming positions.
    Type: Grant
    Filed: June 13, 2001
    Date of Patent: February 11, 2003
    Assignee: Minolta Co., Ltd.
    Inventors: Seiichi Munemori, Takanobu Yamada, Yuusuke Morikami
  • Patent number: 6463236
    Abstract: An image forming apparatus comprising an intermediate transfer belt 12 having a horizontal belt part 12a, and a transfer section 34 arranged opposite the horizontal belt part 12a of the intermediate transfer belt 12 for transferring to a sheet overlaid images formed on the intermediate transfer belt 12 by a plurality of image forming sections 20Y, 20M, 20C, 20K for overlaying multiple images of respectively different color, wherein a belt unit 110 comprises a frame 112, at least three rollers 14, 16, 18 supported on frame 112, and the intermediate transfer belt 12 supported on the exterior surface of these rollers, and wherein the belt unit 110 can be installed and removed from the image forming apparatus body perpendicular to the shafts of the rollers 14, 16, 18, and parallel to the horizontal part 12a.
    Type: Grant
    Filed: June 6, 2001
    Date of Patent: October 8, 2002
    Assignee: Minolta Co., Ltd.
    Inventors: Yuusuke Morikami, Takanobu Yamada, Seiichi Munemori, Yasunori Nakayama
  • Patent number: 6418294
    Abstract: A color image forming apparatus of the present invention has an intermediate transfer member having a movable surface, a plural image forming units for forming superposed toner images on the intermediate transfer member at a predetermined image forming pitch, and a transfer member for transferring the superposed toner images formed on the intermediate transfer member onto a sheet of paper, wherein the peripheral length of the intermediate transfer member is a non-integral multiple of the image forming pitch.
    Type: Grant
    Filed: June 20, 2001
    Date of Patent: July 9, 2002
    Assignee: Minolta Co., Ltd.
    Inventors: Yuusuke Morikami, Seiichi Munemori, Takanobu Yamada
  • Publication number: 20020003976
    Abstract: A color image forming apparatus of the present invention comprises: an intermediate transfer member being driven to rotate by a driving roller; a plural image forming units for forming superposed toner images on the intermediate transfer member, the plural image forming units being located below the intermediate transfer belt; a transfer member for transferring the superposed toner images formed on the intermediate transfer member onto a sheet of paper in a transfer area; and a pair of rotatable conveyance rollers for conveying the paper to the transfer area in synchronization with the superposed toner images on the intermediate transfer member, wherein a first distance from a image forming position, for the image forming unit located most-downstream in the plural image forming units relative to the movement of the intermediate transfer member, to the transfer area is longer than a second distance from a nipping area formed by the pair of conveyance rollers to the transfer area.
    Type: Application
    Filed: June 28, 2001
    Publication date: January 10, 2002
    Inventors: Seiichi Munemori, Yuusuke Morikami, Takanobu Yamada
  • Publication number: 20020001490
    Abstract: A color image forming apparatus of the present invention comprises an intermediate transfer member having a movable surface, a plural image forming units for forming superposed toner images on the intermediate transfer member at a predetermined image forming pitch, and a transfer member for transferring the superposed toner images formed on the intermediate transfer member onto a sheet of paper, wherein the peripheral length of the intermediate transfer member is a non-integral multiple of the image forming pitch.
    Type: Application
    Filed: June 20, 2001
    Publication date: January 3, 2002
    Inventors: Yuusuke Morikami, Seiichi Munemori, Takanobu Yamada
  • Publication number: 20020001488
    Abstract: A color image forming apparatus in accordance with the present invention comprises: an intermediate transfer member having a movable surface; a plural image forming units for forming toner images on the intermediate transfer member at each of image-forming positions; and a transfer roller for transferring the toner images formed on the intermediate transfer member onto a sheet, the transfer roller having a circumferential length equal to the distance between adjacent image forming positions.
    Type: Application
    Filed: June 13, 2001
    Publication date: January 3, 2002
    Inventors: Seiichi Munemori, Takanobu Yamada, Yuusuke Morikami
  • Publication number: 20010053294
    Abstract: When it is judged that a sheet S is not an ordinary paper but a thick paper or an OHP film sheet, or that the arrival of the sheet S at a pair of timing rollers 48 is delayed due to a slip for example beyond an allowable period of time, a controller 70 judges that a condition for transferring or fixing an image on the sheet S is not met. As a result, a secondary transfer roller 34 and a cleaner 38 are retreated from an intermediate transfer belt 12, and in this state, the intermediate transfer belt 12 carrying a toner image I thereon is made idle at least about one revolution without transferring the image I.
    Type: Application
    Filed: June 13, 2001
    Publication date: December 20, 2001
    Inventors: Takanobu Yamada, Seiichi Munemori, Yuusuke Morikami
  • Publication number: 20010051059
    Abstract: An image forming apparatus comprising an intermediate transfer belt 12 having a horizontal belt part 12a, and a transfer section 34 arranged opposite the horizontal belt part 12a of the intermediate transfer belt 12 for transferring to a sheet overlaid images formed on the intermediate transfer belt 12 by a plurality of image forming sections 20Y, 20M, 20C, 20K for overlaying multiple images of respectively different color, wherein a belt unit 110 comprises a frame 112, at least three rollers 14, 16, 18 supported on frame 112, and the intermediate transfer belt 12 supported on the exterior surface of these rollers, and wherein the belt unit 110 can be installed and removed from the image forming apparatus body perpendicular to the shafts of the rollers 14, 16, 18, and parallel to the horizontal belt part 12a.
    Type: Application
    Filed: June 6, 2001
    Publication date: December 13, 2001
    Inventors: Yuusuke Morikami, Takanobu Yamada, Seiichi Munemori, Yasunori Nakayama
  • Patent number: 6008911
    Abstract: In a digital image forming apparatus wherein a user can change a gradation curve of the density of reproduced image plotted against the input image signal obtained by reading a document, it is needed to compensate a change of color of a reproduced image accompanied by the selection of a changed gradation curve. Then, when input multi-tone image signals of R, G and B are converted to multi-tone image signals of Y, M and C for printing, the masking coefficient used for the conversion from R, G and B to Y, M and C is changed according to the changed gradation curve. Then, the multi-tone image signals of Y, M and C are converted to light quantity data of a beam for exposing a photoconductor to form an image on the photoconductor according to the gradation curve.
    Type: Grant
    Filed: May 17, 1993
    Date of Patent: December 28, 1999
    Assignee: Minolta Co., Ltd.
    Inventors: Kazuyuki Fukui, Yoshinobu Hada, Takanobu Yamada, Hiroyuki Ideyama
  • Patent number: 6006010
    Abstract: In a digital image forming apparatus, a document image is read as digital data, and an image type of bi-level image or multi-level image is discriminated from the digital data. For a bi-level image, an intensity of laser beam for exposing a photoconductor is modulated according to the image data with a duty ratio of 100%. On the other hand, for a multi-level image such as a photograph image, the intensity of laser beam is modulated with a duty ratio in the unit of two or more dots according to the image data. The duty ratio and the laser output power are changed according to a type or document image or according to sensitivity characteristic of the photoconductor.
    Type: Grant
    Filed: November 24, 1997
    Date of Patent: December 21, 1999
    Assignee: Minolta Co., Ltd.
    Inventors: Yoshinobu Hada, Kazuyuki Fukui, Takanobu Yamada
  • Patent number: 5974282
    Abstract: The present invention is directed an image forming apparatus as a Tandem type color copying machine in which a paper 11 is fed to a predetermined portion where an image is transferred to the paper. In a case where an image which is adversely affected by a seam 10a of a transporting belt 10, such as a color image or a photo image, is transferred to the paper 11, the paper 11 is fed to the transporting belt 10 so as not to overlap the seam 10a. In a case where an image which is not affected by the seam, such as a white-and-black image or a text image, is transferred to the paper 11, the paper 11 is fed to the transporting belt 10 regardless of the position of the seam 10a.
    Type: Grant
    Filed: January 12, 1999
    Date of Patent: October 26, 1999
    Assignee: Minolta Co., Ltd.
    Inventor: Takanobu Yamada
  • Patent number: 5959650
    Abstract: In a method for forming a digital image with use of electrophotographic process wherein the gradation is expressed by changing the laser intensity according to image information, at least one of the surface electric potential V.sub.O of photoconductor and the development bias electric voltage V.sub.B is controlled, and the laser intensity is controlled for gradation correction to compensate a change in gradation due to the control of V.sub.O and V.sub.B.
    Type: Grant
    Filed: August 10, 1993
    Date of Patent: September 28, 1999
    Assignee: Minolta Co., Ltd.
    Inventors: Kazuyuki Fukui, Takanobu Yamada
  • Patent number: 5893009
    Abstract: An image forming apparatus and an image forming method capable of preventing image noise caused by separation discharge between a photosensitive member and a recording sheet while suppressing to a minimum limit the reduction in production efficiency, by detecting environmental conditions and changing the transport spacing of the recording sheet in accordance with the detected environmental conditions.
    Type: Grant
    Filed: May 15, 1998
    Date of Patent: April 6, 1999
    Assignee: Minolta Co., Ltd.
    Inventor: Takanobu Yamada
  • Patent number: 5729626
    Abstract: In a digital image forming apparatus, a document image is read as digital data, and an image type of bi-level image or multi-level image is discriminated from the digital data. For a bi-level image, an intensity of laser beam for exposing a photoconductor is modulated according to the image data with a duty ratio of 100%. On the other hand, for a multi-level image such as a photograph image, the intensity of laser beam is modulated with a duty ratio in the unit of two or more dots according to the image data. The duty ratio and the laser output power are changed according to a type of document image or according to sensitivity characteristic of the photoconductor.
    Type: Grant
    Filed: December 28, 1994
    Date of Patent: March 17, 1998
    Assignee: Minolta Co., Ltd.
    Inventors: Yoshinobu Hada, Kazuyuki Fukui, Takanobu Yamada
  • Patent number: 5719613
    Abstract: In a apparatus for forming a digital image with use of electrophotographic process wherein the gradation is expressed by changing the laser intensity according to image information, at least one of the surface electric potential V.sub.O of photoconductor and the development bias electric voltage V.sub.B is controlled, and the laser intensity is controlled for gradation correction to compensate a change in gradation due to the control of V.sub.O and V.sub.B. A ratio of variable differences of potential in the apparatus, (V.sub.B -V.sub.I)/(V.sub.O -V.sub.I), is kept constant to control the gamma characteristic in the apparatus.
    Type: Grant
    Filed: June 1, 1995
    Date of Patent: February 17, 1998
    Assignee: Minolta Co., Ltd.
    Inventors: Kazuyuki Fukui, Takanobu Yamada
  • Patent number: 5708919
    Abstract: An image forming apparatus for forming images on both surfaces of a recording sheet. It is discriminated from image signals obtained by scanning a first surface and a second surface of an original which surface has more or less toner consumption, and the image formation sequence is controlled so that an image, which has been judged to have less toner consumption, is first formed on the first surface of the recording medium while an image, which has been judged to have more toner consumption, is formed on the second surface of the recording sheet afterward. Also, in the formation process of the image, which has been judged to have less toner consumption, the fixing roller is not coated with anti-offset liquid, but in the formation process of the image, which has been judged to have more toner consumption, it is controlled so that the fixing roller is coated with the anti-offset liquid.
    Type: Grant
    Filed: May 1, 1996
    Date of Patent: January 13, 1998
    Assignee: Minolta Co., Ltd.
    Inventors: Takanobu Yamada, Hidehiko Shibano
  • Patent number: 5663814
    Abstract: In an electrophotographic process, a laser beam exposes a photoconductor according to image density level to form a latent image. In the exposure, a duty ratio of light emission period to a length of a dot is changed according to the density level. In a first mode, the duty ratio is decreased with the density level if the density level is lower than a predetermined density level, while in a second mode, the duty ratio is increased if the density level is higher than a predetermined density level. Thus, the nonlinearity of gradation characteristic is improved. A user can select a desired mode among three modes on the duty ratio to reproduce an image of desired image quality. Thus, the nonlinearity of gradation characteristic is improved, and an image can be reproduced stably.
    Type: Grant
    Filed: December 29, 1994
    Date of Patent: September 2, 1997
    Assignee: Minolta Co., Ltd.
    Inventors: Yoshinobu Hada, Kazuyuki Fukui, Takanobu Yamada
  • Patent number: 5585927
    Abstract: In a digital image forming apparatus, a user can select a desired gradation curve representing the relation of the density of reproduced image to the input image signal obtained by reading a document among a plurality of gradation data stored in a memory in correspondence to image forming conditions of an electrophotographic process of forming an image. The image forming condition is determined separately. A gradation correction data is calculated from the gradation data to realize the object gradation curve. Then, an input image signal is converted to light quantity data for a beam for exposing a photoconductor by using the calculated gradation correction data to form a latent image on a photoconductor in the image forming conditions.
    Type: Grant
    Filed: May 17, 1993
    Date of Patent: December 17, 1996
    Assignee: Minolta Camera Kabushiki Kaisha
    Inventors: Kazuyuki Fukui, Takanobu Yamada, Yoshinobu Hada, Hiroyuki Ideyama, Yasuhiro Ohno
  • Patent number: 5539500
    Abstract: An image forming apparatus for forming images by an electrophotographic process. The image forming apparatus includes a humidity sensor for detecting the humidity in the area around the image forming members provided therein, a density sensor for detecting the density of images formed on a photoreceptor, and a humidity controller having a dehumidifying unit and a humidifying unit for adjusting the humidity in the area around image forming members. The humidity controller is operated according to humidity historical data generated based on the humidity data outputed from the humidity sensor, a detected photoreceptor potential, a detected amount of developer scattered from the developing unit or the detection result from the density sensor.
    Type: Grant
    Filed: July 28, 1995
    Date of Patent: July 23, 1996
    Assignee: Minolta Camera Kabushiki Kaisha
    Inventors: Suguru Hamamichi, Naoyoshi Kinoshita, Takeru Kinoshita, Takanobu Yamada, Hideo Kitakubo