Patents by Inventor Daisuke Akagi

Daisuke Akagi 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: 9256154
    Abstract: An image forming apparatus, including: a laser light source supplied with a bias current and a superimposed current to emit laser light; a splitting unit configured to split the laser light into first and second laser lights; a photoelectric conversion unit configured to output a voltage corresponding to a light intensity of the second laser light; a voltage holding unit configured to hold a voltage output from the photoelectric conversion unit with not the superimposed current but the bias current being supplied to the laser light source; a voltage conversion unit configured to remove the voltage held by the voltage holding unit from the voltage from the photoelectric conversion unit which receives the second laser light; and a current control unit configured to control, based on a voltage from the voltage conversion unit, a value of the superimposed current supplied to the laser light source based on image data.
    Type: Grant
    Filed: August 25, 2014
    Date of Patent: February 9, 2016
    Assignee: CANON KABUSHIKI KAISHA
    Inventor: Daisuke Akagi
  • Patent number: 9250562
    Abstract: An image forming apparatus causes a BD sensor to generate two BD signals based on laser beams emitted from first and second light-emitting portions and measures the generation timing difference therebetween. When measurement is to be executed, the image forming apparatus executes APC as light power control on the first light-emitting portion that emits a laser beam for causing the BD sensor 210 to generate the first BD signal. On the other hand, the image forming apparatus executes ACC, rather than APC, as light power control on the second light-emitting portion that emits a laser beam for causing the BD sensor to generate the second BD signal that follows the first BD signal.
    Type: Grant
    Filed: April 1, 2015
    Date of Patent: February 2, 2016
    Assignee: CANON KABUSHIKI KAISHA
    Inventor: Daisuke Akagi
  • Publication number: 20150338765
    Abstract: A determination unit determines a bias current caused to flow through at least plurality of light-emitting portions regardless of image data during an image period by determining a first drive current for setting a light quantity of a light beam incident on a light reception unit during the non-image period to a first target light quantity, and determining a second drive current for setting a light quantity of a light beam incident on the light receiving unit to a second target light quantity that is different from the first target light quantity. The determination unit determines a drive current for performing switch-driving of the plurality of light-emitting portions, based on image data, the drive current corresponding to the first drive current and the bias current upon the image data being generated in a second section of a non-image period.
    Type: Application
    Filed: May 12, 2015
    Publication date: November 26, 2015
    Inventor: Daisuke Akagi
  • Publication number: 20150286160
    Abstract: An image forming apparatus causes a BD sensor to generate two BD signals based on laser beams emitted from first and second light-emitting portions and measures the generation timing difference therebetween. When measurement is to be executed, the image forming apparatus executes APC as light power control on the first light-emitting portion that emits a laser beam for causing the BD sensor 210 to generate the first BD signal. On the other hand, the image forming apparatus executes ACC, rather than APC, as light power control on the second light-emitting portion that emits a laser beam for causing the BD sensor to generate the second BD signal that follows the first BD signal.
    Type: Application
    Filed: April 1, 2015
    Publication date: October 8, 2015
    Inventor: Daisuke Akagi
  • Publication number: 20150062276
    Abstract: An image forming apparatus, including: a laser light source supplied with a bias current and a superimposed current to emit laser light; a splitting unit configured to split the laser light into first and second laser lights; a photoelectric conversion unit configured to output a voltage corresponding to a light intensity of the second laser light; a voltage holding unit configured to hold a voltage output from the photoelectric conversion unit with not the superimposed current but the bias current being supplied to the laser light source; a voltage conversion unit configured to remove the voltage held by the voltage holding unit from the voltage from the photoelectric conversion unit which receives the second laser light; and a current control unit configured to control, based on a voltage from the voltage conversion unit, a value of the superimposed current supplied to the laser light source based on image data.
    Type: Application
    Filed: August 25, 2014
    Publication date: March 5, 2015
    Inventor: Daisuke Akagi
  • Patent number: 8922613
    Abstract: A light beam scanning device which is capable of performing high-accuracy light amount control without complicated control even when the device includes a laser diode having non-linear I-L characteristics. Gain circuits set the amount of light to be emitted from the laser diode. A PD circuit board detects the amount of the emitted light. A laser controller controls the amount of the emitted light by adjusting drive current applied to the laser diode based on a detection output from the PD circuit board. A CPU corrects data for correcting the drive current. The CPU decides a light amount correction range for correcting the light amount based on the correction data, calculates the slope of the I-L characteristics in the light amount correction range based on light amounts at two points within the light amount correction range and drive currents associated with the respective light amounts, and corrects the correction data using the calculated slope.
    Type: Grant
    Filed: April 26, 2013
    Date of Patent: December 30, 2014
    Assignee: Canon Kabushiki Kaisha
    Inventor: Daisuke Akagi
  • Publication number: 20140368596
    Abstract: An exposure apparatus according to one aspect of this invention includes a plurality of laser light sources (LDs) each configured to output a laser beam of a light power corresponding to a supplied current. The exposure apparatus exposes the surface of a photosensitive drum with a plurality of laser beams. When determining the incident states of the laser beams on the light-receiving surface of a PD, a CPU controls at least one LD as a control target. The CPU causes the control target LD by a current of a predetermined magnitude to emit light and output a laser beam. Based on a light power detection value from the PD for a laser beam output from the control target LD, the CPU determines the incident state of the laser beam on the light-receiving surface of the PD.
    Type: Application
    Filed: May 29, 2014
    Publication date: December 18, 2014
    Applicant: Canon Kabushiki Kaisha
    Inventor: Daisuke Akagi
  • Publication number: 20140321490
    Abstract: A laser drive device capable of easily reducing influence of bias light emission and thereby preventing variation in threshold current. A light amount of a laser beam emitted from a laser diode is detected by a photodiode. A drive current supplied to the laser diode is controlled according to the detected light amount to thereby control the amount of light emitted from the laser diode to a plurality of set light amounts. A threshold current is calculated according to the detected light amount and the drive current. The light amounts are changed and selected, and threshold currents calculated with respect to respective set light amounts are compared. A light amount corresponding to a difference in threshold current not less than a predetermined value is set as a set light amount for use in light amount control of the laser diode.
    Type: Application
    Filed: April 22, 2014
    Publication date: October 30, 2014
    Applicant: CANON KABUSHIKI KAISHA
    Inventor: Daisuke Akagi
  • Publication number: 20130287418
    Abstract: A light beam scanning device which is capable of performing high-accuracy light amount control without complicated control even when the device includes a laser diode having non-linear I-L characteristics. Gain circuits set the amount of light to be emitted from the laser diode. A PD circuit board detects the amount of the emitted light. A laser controller controls the amount of the emitted light by adjusting drive current applied to the laser diode based on a detection output from the PD circuit board. A CPU corrects data for correcting the drive current. The CPU decides a light amount correction range for correcting the light amount based on the correction data, calculates the slope of the I-L characteristics in the light amount correction range based on light amounts at two points within the light amount correction range and drive currents associated with the respective light amounts, and corrects the correction data using the calculated slope.
    Type: Application
    Filed: April 26, 2013
    Publication date: October 31, 2013
    Applicant: CANON KABUSHIKI KAISHA
    Inventor: Daisuke Akagi