Patents by Inventor Kentaro Katori

Kentaro Katori 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: 6094502
    Abstract: In a copying machine, a printer control unit calculates .gamma. correction data according to a grid potential Vg and a development bias potential Vb which are image forming parameters, and a calculation coefficient. The printer control unit reads reflectance data of a copied test pattern in a test pattern read out mode to correct the calculation coefficient for the calculation of .gamma. correction data according to the read out data. Thus, .gamma. correction at always the optimum and accurate level can be carried out without usage of a memory of a large capacity.
    Type: Grant
    Filed: March 11, 1997
    Date of Patent: July 25, 2000
    Assignee: Minolta Co., Ltd.
    Inventors: Katsuyuki Hirata, Kentaro Katori, Masaki Tanaka
  • Patent number: 6028957
    Abstract: Pixel data comprising density data of R, G, and B obtained by reading an original with a CCD image sensor are subjected to shading correction by a shading correction unit, and then converted into color region signals H*, V, and C* in the Munsell color space by a first converter. According to the variations of V, a region discriminator determines whether each pixel data belongs to an edge portion of the original image or whether it belongs to a uniform density region of the original image. A noise removing unit performs noise removal by performing smoothing on color region signals H*, V, and C* of the pixel data which have been determined to belong to uniform density regions. A second converter converts the noise-removed color region signals into pixel data of R, G, and B.
    Type: Grant
    Filed: March 6, 1997
    Date of Patent: February 22, 2000
    Assignee: Minolta Co., Ltd.
    Inventors: Kentaro Katori, Yoshinobu Hada, Masahiro Kouzaki, Yukihiko Okuno, Katsuyuki Hirata
  • Patent number: 5999279
    Abstract: An image forming apparatus which forms an image according to image data made up of pixel data on colors of pixel constituting an original image, characterized by comprising a color region discriminator for determining to which color region each pixel data belongs, an image region discriminator for determining whether the pixel data belongs to a uniform density region or whether it belongs to an edge portion, a corrective condition deciding unit for determining MTF corrective conditions for the image data of each color region depending on the discrimination results of both the color region discriminator and the image region discriminator, and an MTF correction unit for performing MTF corrections on the image data according to the MTF corrective conditions determined by the corrective condition deciding unit.
    Type: Grant
    Filed: February 27, 1997
    Date of Patent: December 7, 1999
    Assignee: Minolta Co., Ltd.
    Inventors: Masahiro Kouzaki, Yoshinobu Hada, Yukihiko Okuno, Kentaro Katori, Katsuyuki Hirata
  • Patent number: 5966222
    Abstract: The individual pattern of each color of the standard pattern is printed on a copy being made, and when the copy is read by a scanner, the image data of the standard pattern are converted into color region signals in a uniform color space by an HVC converter and a C.multidot.H operation unit. In the case where the saturation of the image data has become lower than the standard saturation of the color region, saturation corrective coefficients are determined by a saturation corrective coefficient calculation unit. After the saturation coefficients have been determined for each color of the standard pattern, the image data of the original are read out, and the saturation corrective coefficients for the color region of the image data are used for saturation correction by a saturation correction processing unit. The image data which have been subjected to the saturation correction are reversely converted into the image data of each color by a reverse HVC converter.
    Type: Grant
    Filed: March 20, 1997
    Date of Patent: October 12, 1999
    Assignee: Minolta Co., Ltd.
    Inventors: Katsuyuki Hirata, Yoshinobu Hada, Kentaro Katori, Yukihiko Okuno, Masahiro Kouzaki
  • Patent number: 5963766
    Abstract: A supply screw 10 and a collection screw 20 for a developing device equip with screw blades having different forms at particular sections so as to make conveying force of developer different depending on sections. Screw blades for big conveying force are attached within sections where developer distribution is dense while screw blades for small conveying force are attached within sections where developer distribution is sparse. In other words, conveying force is made to be greater at sparse-distribution section while smaller at dense-distribution section. Developer delivery is also promoted by providing different conveying force area within carry-up area where developer is carried up from a supply screw 10 to a collection screw 20 or vice versa. By making conveying force of each section different, developer is uniformly delivered to a developing roll 87 whether in width direction or in axial direction. Furthermore, developer circulation in a developing device becomes smooth.
    Type: Grant
    Filed: June 8, 1998
    Date of Patent: October 5, 1999
    Assignee: Minolta Co., Ltd.
    Inventors: Yukihiko Okuno, Suguru Hamamichi, Shinichi Yoshimoto, Kentaro Katori, Mineyuki Sako, Yoshihiro Shojo
  • Patent number: 5949963
    Abstract: In a digital full color copying machine, one pixel on a photoconductor is divided into four subdivided small pixels. Functions a-d are assigned to each subdivided small pixel. Functions a-d are linear functions with density data as a parameter. The slope of functions a-d becomes smaller in sequential order. Exposure data of the four subdivided small pixels is calculated according to the density data of a pixel and functions a-d to expose each subdivided small pixel. A peak can be established in the exposure amount distribution to form a deeper latent image. Accordingly, resolution and graininess of the halftone area are improved.
    Type: Grant
    Filed: March 12, 1997
    Date of Patent: September 7, 1999
    Assignee: Minolta Co., Ltd.
    Inventors: Katsuyuki Hirata, Kentaro Katori, Yoshinobu Hada, Hironobu Nakata, Yoshihiko Hirota
  • Patent number: 5950056
    Abstract: A developing device capable of preventing a reduction of image quality due to disparities in image density or fogging and the like that result from an nonuniform toner concentration or static charge status due to inadequate mixing of a developer. The developing device is provided with a mixing screw for mixing a developer separately from a supply screw for supplying a developer to a developing roller and a collection screw for collecting a developer from the developing roller, the transport direction of the mixing screw being opposite to the transport direction of the supply screw and collection screw.
    Type: Grant
    Filed: June 16, 1998
    Date of Patent: September 7, 1999
    Assignee: Minolta Co., Ltd.
    Inventors: Suguru Hamamichi, Mineyuki Sako, Kentaro Katori, Shinichi Yoshimoto
  • Patent number: 5933255
    Abstract: In a digital image forming apparatus, when a latent image is formed on a photoconductor by modulating optical intensity of laser beam, the laser beam is emitted in a period of a duty ratio while modulated according to image data, and the image is formed on a sheet of paper. This process is repeated for four colors for a color document. The duty ratio, defined as a ratio of a light-emitting time of a light exposing the photoconductor to a period for exposing a dot, is changed in the same document. For example, the light emission timing pattern is changed between odd and even lines. In another example, the light-emission timings may be changed at least for one of the reproduction colors. The light-emission timing patterns may be provided for each of reproduction colors. The light-emission timing patterns may be changed to have a constant or different screening angle between colors. Image quality of a half-tone image is improved by using such patterns.
    Type: Grant
    Filed: March 4, 1996
    Date of Patent: August 3, 1999
    Assignee: Minolta Co., Ltd.
    Inventors: Katsuyuki Hirata, Yoshinobu Hada, Kentaro Katori, Masahiro Kouzaki
  • Patent number: 5822079
    Abstract: An image forming apparatus is provided which is immune to characteristic variations of a photoconductor and a developer material, which can detect the amount of toner adhering to a test toner image accurately, and which can always form a favorable image using an optimal image forming parameter. A predetermined test toner image is formed on the photoconductor using developing devices. The amount of toner adhering to the formed test toner image is detected by an AIDC sensor. A printer control unit determines grid potential Vg of a corona charger and development bias potential Vb of each developing device based on the detected amount of adhering toner. A predetermined image is formed using the determined grid potential and development bias potential.
    Type: Grant
    Filed: March 6, 1996
    Date of Patent: October 13, 1998
    Assignee: Minolta Co., Ltd.
    Inventors: Yukihiko Okuno, Toshifumi Watanabe, Kentaro Katori
  • Patent number: 5754920
    Abstract: The present invention relates to an image forming apparatus for copiers, printers and the like. In the image forming apparatus, a standard pattern image, the density of which is detected by a sensor for controlling conditions of image forming operations, is formed on a photosensitive member. Density values are sampled at a plurality of sampling points on a standard pattern image by operating the sensor with a timing at which said sensor confronts said standard pattern image, and are mutually compared with each other. If the comparison result indicates that the timing of the sampling operation lags the standard pattern image, the sampling timing is corrected by eliminating the timing lag. The sampling operation of a subsequent sampling cycle is thereby conducted based on a corrected timing.
    Type: Grant
    Filed: February 26, 1997
    Date of Patent: May 19, 1998
    Assignee: Minolta Co., Ltd.
    Inventors: Masaki Tanaka, Kentaro Katori, Atsushi Kawai, Hironobu Nakata
  • Patent number: 5715067
    Abstract: In a digital image forming apparatus, when a latent image is formed on a photoconductor, a light from a light source is emitted in a period of a duty ratio while modulated according to image data, and the latent image is developed and transferred onto a sheet of paper. The duty ratio, defined as a ratio of a light-emitting time of a light exposing the photoconductor to a period for exposing a dot, is changed in the same document according to dot information on the document such as an edge signal. In the modulation of the optical intensity, the light emission onto the photoconductor is performed with a duty ratio which may be set for each dot. Image portions formed with different duty ratios may exist at the same time in a reproduced image. For example, an edge portion in a document is reproduced at the duty ratio of 100% while a non-edge portion is reproduced at the duty ratio less than 100%.
    Type: Grant
    Filed: March 4, 1996
    Date of Patent: February 3, 1998
    Assignee: Minolta Co., Ltd.
    Inventors: Kentaro Katori, Masahiro Kouzaki, Yoshinobu Hada, Yukihiko Okuno, Katsuyuki Hirata
  • Patent number: 5694223
    Abstract: A printer control unit carries out a predetermined calculation based on the amount of adhering toner detected by an AIDC sensor and the surface potential of a photoconductor detected by a V sensor to correct the light emission intensity of a light source to prepare light emission characteristic data for .gamma. correction to obtain an optimal image. A .gamma. correcting unit corrects an image signal output from an image signal processing unit using the calculated light emission characteristic data for .gamma. correction to control the light source to emit light based on the corrected data. More specifically, since the .gamma. correction data is obtained by calculation, optimal .gamma. correction can always be carried out without a memory of a large capacity.
    Type: Grant
    Filed: March 6, 1996
    Date of Patent: December 2, 1997
    Assignee: Minolta Co., Ltd.
    Inventors: Kentaro Katori, Toshifumi Watanabe, Yukihiko Okuno, Masaki Tanaka, Hironobu Nakata, Katsuyuki Hirata