Patents by Inventor Tomohisa Itagaki

Tomohisa Itagaki 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: 9057974
    Abstract: An image forming apparatus capable of suppressing density unevenness of a toner image formed on a photosensitive member. A light amount of a light beam that exposes an end portion of the photosensitive member is made different from a light amount of a light beam that exposes a central portion thereof in order to suppress a density difference between a toner image density at the central portion of the photosensitive member and that at the end portion thereof in a scanning direction of the light beams.
    Type: Grant
    Filed: July 12, 2013
    Date of Patent: June 16, 2015
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Takahiro Ishihara, Tomohisa Itagaki, Nobuhiko Zaima, Yasuhito Shirafuji
  • Patent number: 9031468
    Abstract: An image forming apparatus includes an image forming unit configured to form a measurement image on a recording paper, a fixing unit configured to fix the measurement image onto the recording paper by heating, a measurement unit configured to measure the measurement image fixed on the recording paper downstream of the fixing unit in a conveyance direction of the recording paper, and a correction unit configured to correct a measurement value output from the measurement unit such that an effect of temperature of the recording paper is decreased when the measurement unit measures the measurement image. The correction unit is configured not to correct the measurement value in a case where density of the measurement image is measured by the measurement unit, and the correction unit is configured to correct the measurement value in a case where chromaticity of the measurement image is measured by the measurement unit.
    Type: Grant
    Filed: November 28, 2012
    Date of Patent: May 12, 2015
    Assignee: Canon Kabushiki Kaisha
    Inventor: Tomohisa Itagaki
  • Patent number: 8958123
    Abstract: The present invention provides an image forming apparatus that forms a test pattern for controlling the amount of color material, suppresses increase of the color material amount, and prevents image defects such as spattering, poor fixation due to granularity, or the like. To accomplish this, the image forming apparatus forms a test pattern on printing material using color material of a plurality of colors, reads the formed test pattern, and controls the color material amount of each color by changing an image forming condition in accordance with a result of the reading. Note that the image forming apparatus forms a mixed pattern image using color material of a plurality of chromatic colors, and controls the amount of color material of a single color based on the mixed pattern image.
    Type: Grant
    Filed: September 5, 2012
    Date of Patent: February 17, 2015
    Assignee: Canon Kabushiki Kaisha
    Inventor: Tomohisa Itagaki
  • Patent number: 8929757
    Abstract: An image forming apparatus includes an image forming unit having an exposure unit and a developing unit; a detection unit configured to detect a thickness and an area ratio of a toner layer of a pattern image formed by the image forming unit; a storage unit configured to store data indicating permissible ranges for the thickness and the area ratio of the toner layer; and a correction unit configured to change, when the thickness or the area ratio of the toner layer detected by the detection unit falls outside the corresponding permissible range indicated by the data stored in the storage unit, a spot diameter of the laser beam so that the thickness and the area ratio of the toner layer respectively fall within the permissible ranges.
    Type: Grant
    Filed: June 6, 2012
    Date of Patent: January 6, 2015
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yasuhito Shirafuji, Tomohisa Itagaki, Nobuhiko Zaima, Takahiro Ishihara
  • Publication number: 20140363183
    Abstract: An image forming apparatus includes; an exposure unit configured to perform, based on the image data, first exposure for a photosensitive member and second exposure for the photosensitive member exposed by the first exposure; a determination unit configured to determine a type of the image to be formed based on image data; and a control unit configured to control the exposure unit such that a difference in an exposure amount between the first exposure and the second exposure performed based on the image data when the type of the image is a character is larger than the difference in the exposure amount between the first exposure and the second exposure performed based on the image data when the type of the image is a picture.
    Type: Application
    Filed: August 26, 2014
    Publication date: December 11, 2014
    Inventors: Nobuhiko Zaima, Tomohisa Itagaki, Takahiro Ishihara, Yasuhito Shirafuji
  • Patent number: 8908225
    Abstract: An apparatus includes a forming unit; a reading unit; a conversion unit converting a signal corresponding to the image read by the reading unit into a signal indicating a density value; a correction unit performing tone correction on the density value of the signal output by the conversion unit; and a control unit controlling a tone correction setting in the tone correction unit by controlling the reading unit to read a tone correction image that was formed on a recording material by the forming unit. When controlling the tone correction setting, the control unit further changes a setting for image formation in the forming unit and a setting for conversion into a density value in the conversion unit according to the recording material used in the control of the tone correction setting.
    Type: Grant
    Filed: May 16, 2012
    Date of Patent: December 9, 2014
    Assignee: Canon Kabushiki Kaisha
    Inventors: Nobuhiko Zaima, Tomohisa Itagaki, Yasuhito Shirafuji, Takahiro Ishihara
  • Patent number: 8854408
    Abstract: An image forming apparatus includes; an exposure unit configured to perform, based on the image data, first exposure for a photosensitive member and second exposure for the photosensitive member exposed by the first exposure; a determination unit configured to determine a type of the image to be formed based on image data; and a control unit configured to control the exposure unit such that a difference in an exposure amount between the first exposure and the second exposure performed based on the image data when the type of the image is a character is larger than the difference in the exposure amount between the first exposure and the second exposure performed based on the image data when the type of the image is a picture.
    Type: Grant
    Filed: January 31, 2013
    Date of Patent: October 7, 2014
    Inventors: Nobuhiko Zaima, Tomohisa Itagaki, Takahiro Ishihara, Yasuhito Shirafuji
  • Publication number: 20140255051
    Abstract: An image forming apparatus includes a feeding unit configured to feed a sheet, an image forming unit configured to form a measurement image on the sheet fed by the feeding unit, a measuring unit configured to measure the measurement image formed on the sheet by the image forming unit, and an adjustment unit configured to perform an adjustment operation on basis of a measurement result of the measurement image. In this case, the image forming unit forms the measurement image of a first side of the sheet and forms a setting aid image on a second side that is different from the first side, and the setting aid image shows information describing the direction of the sheet for setting in the feeding unit and information for prompting to set the sheet with the second side up in the feeding unit.
    Type: Application
    Filed: March 4, 2014
    Publication date: September 11, 2014
    Applicant: CANON KABUSHIKI KAISHA
    Inventor: Tomohisa Itagaki
  • Patent number: 8797615
    Abstract: An image forming apparatus includes an image forming station for forming a pattern image on a recording material; an image reading station for reading a pattern image formed on a recording material by the image forming station; and a tone gradation corrector for calculating a halftone dot area property on the basis of the density of the pattern image read by the image reading station and for executing tone gradation correction in the image forming station on the basis of the calculated halftone dot area property.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: August 5, 2014
    Assignee: Canon Kabushiki Kaisha
    Inventor: Tomohisa Itagaki
  • Publication number: 20140112672
    Abstract: An image forming apparatus includes a fixing unit configured to heat and fix a measurement image formed by an image forming unit to a sheet, a measurement unit arranged downstream of the fixing unit in a conveyance direction of the sheet and configured to measure color of the fixed measurement image, a conversion unit configured to convert a measurement result of the measurement unit into a measurement result at a predetermined temperature based on conversion setting information set in advance, a setting unit configured to set a mode for generating the conversion setting information, and a generation unit configured to generate the conversion setting information by causing the image forming unit to form the measurement image on the sheet, causing the fixing unit to fix the formed measurement image, and causing the measurement unit to repeatedly measure the fixed measurement image in response to setting of the mode.
    Type: Application
    Filed: October 21, 2013
    Publication date: April 24, 2014
    Applicant: CANON KABUSHIKI KAISHA
    Inventor: Tomohisa Itagaki
  • Patent number: 8666265
    Abstract: An image forming apparatus that is capable of reducing a sequential variation of graininess and keeping imaging quality. An exposure unit exposes the photoconductor to a light beam to form an electrostatic latent image. A development unit develops the electrostatic latent image with a toner. A change unit changes a height of toner image by changing an exposure spot area of the light beam on the photoconductor. A formation unit forms test patterns corresponding to different exposure spot areas on a recording sheet. A read unit reads the test patterns. A control unit detects graininess of each test pattern based on information about the test patterns read by the read unit, determines an exposure spot area where the graininess becomes good relatively, and controls the height of toner image on the photoconductor by setting the exposure spot area determined so as to be an exposure spot area for image formation.
    Type: Grant
    Filed: February 6, 2012
    Date of Patent: March 4, 2014
    Assignee: Canon Kabushiki Kaisha
    Inventors: Takahiro Ishihara, Tomohisa Itagaki, Nobuhiko Zaima, Yasuhito Shirafuji
  • Publication number: 20140036020
    Abstract: An image forming apparatus capable of suppressing density unevenness of a toner image formed on a photosensitive member. A light amount of a light beam that exposes an end portion of the photosensitive member is made different from a light amount of a light beam that exposes a central portion thereof in order to suppress a density difference between a toner image density at the central portion of the photosensitive member and that at the end portion thereof in a scanning direction of the light beams.
    Type: Application
    Filed: July 12, 2013
    Publication date: February 6, 2014
    Inventors: Takahiro ISHIHARA, Tomohisa ITAGAKI, Nobuhiko ZAIMA, Yasuhito SHIRAFUJI
  • Publication number: 20130271794
    Abstract: An image forming apparatus includes an image forming station for forming a pattern image on a recording material; an image reading station for reading a pattern image formed on a recording material by the image forming station; and a tone gradation corrector for calculating a halftone dot area property on the basis of the density of the pattern image read by the image reading station and for executing tone gradation correction in the image forming station on the basis of the calculated halftone dot area property.
    Type: Application
    Filed: March 15, 2013
    Publication date: October 17, 2013
    Inventor: Tomohisa ITAGAKI
  • Publication number: 20130243451
    Abstract: Temperature of a printing medium 110 is sufficiently decreased by stopping the printing medium 110 in a discharge path, conveying the printing medium at a low speed, switching a conveyance path, or the like. If the temperature of the printing medium 110 can be sufficiently decreased, the thermochromism phenomenon is suppressed. As a result, it is possible to provide an image forming apparatus capable of achieving highly accurate color matching and color stability.
    Type: Application
    Filed: August 21, 2012
    Publication date: September 19, 2013
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Kenichi Hirota, Taichi Takemura, Tomohisa Itagaki
  • Patent number: 8432579
    Abstract: An image forming apparatus includes an image forming station for forming a pattern image on a recording material; an image reading station for reading a pattern image formed on a recording material by the image forming station; and a tone gradation corrector for calculating a halftone dot area property on the basis of the density of the pattern image read by the image reading station and for executing tone gradation correction in the image forming station on the basis of the calculated halftone dot area property.
    Type: Grant
    Filed: February 25, 2011
    Date of Patent: April 30, 2013
    Assignee: Canon Kabushiki Kaisha
    Inventor: Tomohisa Itagaki
  • Publication number: 20130094036
    Abstract: The present invention provides an image forming apparatus that forms a test pattern for controlling the amount of color material, suppresses increase of the color material amount, and prevents image defects such as spattering, poor fixation due to granularity, or the like. To accomplish this, the image forming apparatus forms a test pattern on printing material using color material of a plurality of colors, reads the formed test pattern, and controls the color material amount of each color by changing an image forming condition in accordance with a result of the reading. Note that the image forming apparatus forms a mixed pattern image using color material of a plurality of chromatic colors, and controls the amount of color material of a single color based on the mixed pattern image.
    Type: Application
    Filed: September 5, 2012
    Publication date: April 18, 2013
    Applicant: CANON KABUSHIKI KAISHA
    Inventor: Tomohisa Itagaki
  • Publication number: 20130034359
    Abstract: An image forming apparatus configures a normal transfer potential in a yellow primary transfer unit, and configures a transfer potential which does not cause any retransfer phenomenon of a yellow measurement image in image carriers located on the downstream side of the yellow primary transfer unit. When a color difference obtained from a reference density and a density of a measurement image on an intermediate transfer belt becomes equal to or larger than a prescribed value, the image forming apparatus determines that multinary-color density adjustment is required.
    Type: Application
    Filed: July 31, 2012
    Publication date: February 7, 2013
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Yasuhito SHIRAFUJI, Tomohisa ITAGAKI, Nobuhiko ZAIMA, Takahiro ISHIHARA
  • Publication number: 20120321331
    Abstract: An image forming apparatus includes an image forming unit having an exposure unit and a developing unit; a detection unit configured to detect a thickness and an area ratio of a toner layer of a pattern image formed by the image forming unit; a storage unit configured to store data indicating permissible ranges for the thickness and the area ratio of the toner layer; and a correction unit configured to change, when the thickness or the area ratio of the toner layer detected by the detection unit falls outside the corresponding permissible range indicated by the data stored in the storage unit, a spot diameter of the laser beam so that the thickness and the area ratio of the toner layer respectively fall within the permissible ranges.
    Type: Application
    Filed: June 6, 2012
    Publication date: December 20, 2012
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Yasuhito Shirafuji, Tomohisa Itagaki, Nobuhiko Zaima, Takahiro Ishihara
  • Publication number: 20120314227
    Abstract: An apparatus includes a forming unit; a reading unit; a conversion unit converting a signal corresponding to the image read by the reading unit into a signal indicating a density value; a correction unit performing tone correction on the density value of the signal output by the conversion unit; and a control unit controlling a tone correction setting in the tone correction unit by controlling the reading unit to read a tone correction image that was formed on a recording material by the forming unit. When controlling the tone correction setting, the control unit further changes a setting for image formation in the forming unit and a setting for conversion into a density value in the conversion unit according to the recording material used in the control of the tone correction setting.
    Type: Application
    Filed: May 16, 2012
    Publication date: December 13, 2012
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Nobuhiko Zaima, Tomohisa Itagaki, Yasuhito Shirafuji, Takahiro Ishihara
  • Publication number: 20120294643
    Abstract: An image forming apparatus includes a conveyance unit to convey an image carrier and an image forming unit to form an image on the image carrier. The image forming apparatus also includes a first determining unit, a control unit, an irradiation unit, an output unit, and a second determining unit. The first determining unit determines a first image forming condition of the image forming unit for forming a heavy line image at a particular width and thickness. The control unit causes the image forming unit to form a first measurement image having a particular width and length. The irradiation unit emits light onto the image carrier. The output unit outputs a first signal corresponding to a thickness of the first measurement image by receiving reflected light. The second determining unit determines a second image forming condition for forming a fine line image at a particular width and thickness.
    Type: Application
    Filed: February 17, 2012
    Publication date: November 22, 2012
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Tomohisa Itagaki, Nobuhiko Zaima, Yasuhito Shirafuji, Takahiro Ishihara