Patents by Inventor Hisahiro Kamata

Hisahiro Kamata 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: 10044293
    Abstract: An inverter includes transformers having identical characteristics. Exciting windings of the transformers are connected in parallel so that the transformers are excited simultaneously. Output windings of the transformers are connected in series so that waveforms of output voltages of the output windings are time-synchronized. Each transformer includes a core having an identical shape and including an inner leg having an independent closed magnetic circuit. The excitation winding and the output winding are wrapped around the inner leg of the core in layers. The inner leg of the core has a gap whose size is steplessly adjustable in a state where the excitation current is applied to the excitation winding. The size of the gap is adjusted to regulate exciting inductances of the transformers to a same predetermined value.
    Type: Grant
    Filed: March 11, 2014
    Date of Patent: August 7, 2018
    Assignee: Ricoh Company, LTD.
    Inventor: Hisahiro Kamata
  • Patent number: 9819280
    Abstract: An inverter device applies an excitation current to an excitation winding of a step-up transformer through a switching element, and outputs an output voltage with an alternating-current half-wave waveform from an output winding of the step-up transformer. The inverter device includes: an input-voltage detecting unit that detects a state of the input voltage, as a voltage; a current detecting unit that converts a current flowing through the switching element into a voltage to detects the current; and a comparing unit that compares a detected current value detected by the current detecting unit with a detected input voltage value detected by the input-voltage detecting unit, and detects a high-current period in which the detected current value exceeds the detected input voltage value. Based on information indicating the high-current period detected by the comparing unit, the control circuit adjusts a period in which the switching element is turned on.
    Type: Grant
    Filed: February 15, 2016
    Date of Patent: November 14, 2017
    Assignee: Ricoh Company, Ltd.
    Inventors: Hisahiro Kamata, Yoshiyuki Shishido, Masakazu Fujita
  • Patent number: 9799441
    Abstract: A transformer includes: a first winding; a second winding provided to maintain a first distance to the first winding; and a shell that seals the first winding and the second winding.
    Type: Grant
    Filed: March 16, 2016
    Date of Patent: October 24, 2017
    Assignee: RICOH COMPANY, LTD.
    Inventor: Hisahiro Kamata
  • Patent number: 9504136
    Abstract: An inverter device includes: multiple inverters that switch input voltages by turning on and off respective switching elements to thereby apply excitation currents to primary excitation windings of respective boosting transformers and output alternating-current voltages from secondary output windings of the respective boosting transformers, the multiple inverters having the same output characteristics, and a common control circuit, on/off control of the switching elements of the inverters being performed by the same switching signal output from the common control circuit.
    Type: Grant
    Filed: January 15, 2015
    Date of Patent: November 22, 2016
    Assignee: Ricoh Company, Ltd.
    Inventors: Atsushi Nunokawa, Hisahiro Kamata
  • Patent number: 9467071
    Abstract: Excitation current is applied to an excitation winding of a step-up transformer by switching an input voltage with a first switching element. Excitation energy stored causes a voltage resonant state in the secondary side of the step-up transformer during a period when the excitation current is shut off. When the excitation current is shut off, a second resonant circuit provided in the primary side of the step-up transformer enters a resonant state. When a second switching element of the second resonant circuit is turned on, energy returning to an input side in a region where the output voltage is negative is commutated through a second diode to be absorbed in the input voltage. The second switching element is kept off while the second resonant circuit is in the resonant state, turned on when the resonant state ends, and turned off after the first switching element is turned on.
    Type: Grant
    Filed: September 14, 2015
    Date of Patent: October 11, 2016
    Assignee: Ricoh Company, Ltd.
    Inventor: Hisahiro Kamata
  • Publication number: 20160278197
    Abstract: A transformer includes: a first winding; a second winding provided to maintain a first distance to the first winding; and a shell that seals the first winding and the second winding.
    Type: Application
    Filed: March 16, 2016
    Publication date: September 22, 2016
    Inventor: Hisahiro KAMATA
  • Publication number: 20160248336
    Abstract: An inverter device applies an excitation current to an excitation winding of a step-up transformer through a switching element, and outputs an output voltage with an alternating-current half-wave waveform from an output winding of the step-up transformer. The inverter device includes: an input-voltage detecting unit that detects a state of the input voltage, as a voltage; a current detecting unit that converts a current flowing through the switching element into a voltage to detects the current; and a comparing unit that compares a detected current value detected by the current detecting unit with a detected input voltage value detected by the input-voltage detecting unit, and detects a high-current period in which the detected current value exceeds the detected input voltage value. Based on information indicating the high-current period detected by the comparing unit, the control circuit adjusts a period in which the switching element is turned on.
    Type: Application
    Filed: February 15, 2016
    Publication date: August 25, 2016
    Applicant: Ricoh Company, Ltd.
    Inventors: Hisahiro Kamata, Yoshiyuki Shishido, Masakazu Fujita
  • Publication number: 20160081175
    Abstract: Excitation current is applied to an excitation winding of a step-up transformer by switching an input voltage with a first switching element. Excitation energy stored causes a voltage resonant state in the secondary side of the step-up transformer during a period when the excitation current is shut off. When the excitation current is shut off, a second resonant circuit provided in the primary side of the step-up transformer enters a resonant state. When a second switching element of the second resonant circuit is turned on, energy returning to an input side in a region where the output voltage is negative is commutated through a second diode to be absorbed in the input voltage. The second switching element is kept off while the second resonant circuit is in the resonant state, turned on when the resonant state ends, and turned off after the first switching element is turned on.
    Type: Application
    Filed: September 14, 2015
    Publication date: March 17, 2016
    Applicant: Ricoh Company, Ltd.
    Inventor: Hisahiro Kamata
  • Patent number: 9287762
    Abstract: An inverter switches input voltage Vin to flow an excitation current to excitation winding Np of a transformer and output to a discharger an alternating voltage Vout from the output winding Ns. In an output circuit flowing a current to the discharger, a voltage-responsive connector is connected in series with the winding Ns to interrupt or connect the output circuit according to a voltage applied to between opposed electrodes. The voltage-responsive connector has characteristics of keeping the electrodes in an insulated state until an instantaneous value of the alternating voltage reaches a predetermined value, and holding the electrodes in a conduction state while the instantaneous value of the alternating voltage has reached the predetermined value and continues to exceed the predetermined value, and quickly returning the electrodes to the insulated state when the instantaneous value of the alternating voltage has fallen below the predetermined value.
    Type: Grant
    Filed: March 13, 2014
    Date of Patent: March 15, 2016
    Assignee: RICOH COMPANY, LIMITED
    Inventors: Hisahiro Kamata, Eiki Hirama, Masahiro Noguchi
  • Patent number: 9232625
    Abstract: An inverter device includes a switching device which performs on-off switching of an input voltage, a step-up transformer which applies an excitation current to its winding during a switching-device-on period and outputs an output voltage during a switching-device-off period, an input-voltage detector which detects the input voltage and output an input-voltage detection signal, an output voltage detector which detects the output voltage and output an output-voltage detection signal, an output-produced-period detector which detects a period when the output voltage is produced based on the output-voltage detection signal, a comparator which detects a period when the output-voltage detection signal exceeds the input-voltage detection signal and output information indicating the output-high period, and a shifting unit which shifts the information indicating the output-high period to a next period when absence of the output produced period is detected.
    Type: Grant
    Filed: March 13, 2015
    Date of Patent: January 5, 2016
    Assignee: Ricoh Company, Ltd.
    Inventor: Hisahiro Kamata
  • Patent number: 9160225
    Abstract: A high voltage inverter device uses, as an input voltage (Vin), a DC voltage or a voltage composed of a DC component with a pulsating current superposed thereon, switches the input voltage by a switching element (Qsw) to apply an exciting current to an excitation winding (NP) of a resonant transformer (10) and output an alternating-current high voltage (Vout) from an output winding (NS) of the resonant transformer. An abnormal voltage detection circuit (7) including a varistor (12) detects an abnormal voltage generated in the excitation winding (NP) of the resonant transformer (10), and when the abnormal voltage is detected, its signal is transmitted by a photocoupler (11) to a control circuit (20), thereby causing the control circuit (20) to stop its oscillation operation to stop a switching operation of the switching element (Qsw).
    Type: Grant
    Filed: March 6, 2012
    Date of Patent: October 13, 2015
    Assignee: RICOH COMPANY, LTD.
    Inventor: Hisahiro Kamata
  • Publication number: 20150271906
    Abstract: An inverter device includes a switching device which performs on-off switching of an input voltage, a step-up transformer which applies an excitation current to its winding during a switching-device-on period and outputs an output voltage during a switching-device-off period, an input-voltage detector which detects the input voltage and output an input-voltage detection signal, an output voltage detector which detects the output voltage and output an output-voltage detection signal, an output-produced-period detector which detects a period when the output voltage is produced based on the output-voltage detection signal, a comparator which detects a period when the output-voltage detection signal exceeds the input-voltage detection signal and output information indicating the output-high period, and a shifting unit which shifts the information indicating the output-high period to a next period when absence of the output produced period is detected.
    Type: Application
    Filed: March 13, 2015
    Publication date: September 24, 2015
    Applicant: Ricoh Company, Ltd.
    Inventor: Hisahiro Kamata
  • Publication number: 20150200606
    Abstract: An inverter device includes: multiple inverters that switch input voltages by turning on and off respective switching elements to thereby apply excitation currents to primary excitation windings of respective boosting transformers and output alternating-current voltages from secondary output windings of the respective boosting transformers, the multiple inverters having the same output characteristics, and a common control circuit, on/off control of the switching elements of the inverters being performed by the same switching signal output from the common control circuit.
    Type: Application
    Filed: January 15, 2015
    Publication date: July 16, 2015
    Applicant: RICOH COMPANY, LTD.
    Inventors: Atsushi Nunokawa, Hisahiro Kamata
  • Patent number: 9030856
    Abstract: In a high voltage inverter device switching an input voltage to apply an exciting current to an excitation winding of a transformer and output an alternating-current high voltage from an output winding to supply the high voltage to a load from output lines, a point on the output line is connected to a frame ground. Each of a first and a second winding of the electrical leakage detecting transformer is interposed in series with the output line on a side where current flows out of the point and a side where current flows into the point respectively. A detection voltage Vd outputted from an amplifying winding is compared by a comparison voltage Vref, and an electrical leakage detection signal Sd is outputted when Vd>Vref. The first and second winding are opposite in winding direction to each other and equal in number of turns.
    Type: Grant
    Filed: December 19, 2011
    Date of Patent: May 12, 2015
    Assignee: Ricoh Company, Ltd.
    Inventor: Hisahiro Kamata
  • Patent number: 8971081
    Abstract: The high voltage inverter device receives, as an input voltage, a DC voltage or a voltage within Safety Extra Low Voltage composed of a DC component with a pulsating flow superposed thereon. The input voltage is switched by a switching element to pass an exciting current to excitation windings on a primary side of a plurality of separate transformers having same characteristics to simultaneously excite the excitation windings. Output windings of the plurality of transformers are connected in parallel or in series with one another, and time axes of waveforms of output voltages of the output windings are synchronized. Thereby, a high-power high voltage is outputted continuously, stably, and safely from both ends of the output windings connected in parallel or in series.
    Type: Grant
    Filed: March 25, 2011
    Date of Patent: March 3, 2015
    Assignee: Ricoh Company, Ltd.
    Inventor: Hisahiro Kamata
  • Publication number: 20140265911
    Abstract: An inverter switches input voltage Vin to flow an excitation current to excitation winding Np of a transformer and output to a discharger an alternating voltage Vout from the output winding Ns. In an output circuit flowing a current to the discharger, a voltage-responsive connector is connected in series with the winding Ns to interrupt or connect the output circuit according to a voltage applied to between opposed electrodes. The voltage-responsive connector has characteristics of keeping the electrodes in an insulated state until an instantaneous value of the alternating voltage reaches a predetermined value, and holding the electrodes in a conduction state while the instantaneous value of the alternating voltage has reached the predetermined value and continues to exceed the predetermined value, and quickly returning the electrodes to the insulated state when the instantaneous value of the alternating voltage has fallen below the predetermined value.
    Type: Application
    Filed: March 13, 2014
    Publication date: September 18, 2014
    Inventors: Hisahiro KAMATA, Eiki HIRAMA, Masahiro NOGUCHI
  • Publication number: 20140268966
    Abstract: An inverter includes transformers having identical characteristics. Exciting windings of the transformers are connected in parallel so that the transformers are excited simultaneously. Output windings of the transformers are connected in series so that waveforms of output voltages of the output windings are time-synchronized. Each transformer includes a core having an identical shape and including an inner leg having an independent closed magnetic circuit. The excitation winding and the output winding are wrapped around the inner leg of the core in layers. The inner leg of the core has a gap whose size is steplessly adjustable in a state where the excitation current is applied to the excitation winding. The size of the gap is adjusted to regulate exciting inductances of the transformers to a same predetermined value.
    Type: Application
    Filed: March 11, 2014
    Publication date: September 18, 2014
    Applicant: RICOH COMPANY, LIMITED
    Inventor: Hisahiro KAMATA
  • Publication number: 20120236614
    Abstract: A high voltage inverter device uses, as an input voltage (Vin), a DC voltage or a voltage composed of a DC component with a pulsating current superposed thereon, switches the input voltage by a switching element (Qsw) to apply an exciting current to an excitation winding (NP) of a resonant transformer (10) and output an alternating-current high voltage (Vout) from an output winding (NS) of the resonant transformer. An abnormal voltage detection circuit (7) including a varistor (12) detects an abnormal voltage generated in the excitation winding (NP) of the resonant transformer (10), and when the abnormal voltage is detected, its signal is transmitted by a photocoupler (11) to a control circuit (20), thereby causing the control circuit (20) to stop its oscillation operation to stop a switching operation of the switching element (Qsw).
    Type: Application
    Filed: March 6, 2012
    Publication date: September 20, 2012
    Applicant: TOHOKU RICOH CO., LTD.
    Inventor: Hisahiro Kamata
  • Publication number: 20120163058
    Abstract: In a high voltage inverter device switching an input voltage to apply an exciting current to an excitation winding of a transformer and output an alternating-current high voltage from an output winding to supply the high voltage to a load from output lines, a point on the output line is connected to a frame ground. Each of a first and a second winding of the electrical leakage detecting transformer is interposed in series with the output line on a side where current flows out of the point and a side where current flows into the point respectively. A detection voltage Vd outputted from an amplifying winding is compared by a comparison voltage Vref, and an electrical leakage detection signal Sd is outputted when Vd>Vref. The first and second winding are opposite in winding direction to each other and equal in number of turns.
    Type: Application
    Filed: December 19, 2011
    Publication date: June 28, 2012
    Applicant: TOHOKU RICOH CO., LTD.
    Inventor: Hisahiro KAMATA
  • Publication number: 20110235382
    Abstract: The high voltage inverter device receives, as an input voltage, a DC voltage or a voltage within Safety Extra Low Voltage composed of a DC component with a pulsating flow superposed thereon. The input voltage is switched by a switching element to pass an exciting current to excitation windings on a primary side of a plurality of separate transformers having same characteristics to simultaneously excite the excitation windings. Output windings of the plurality of transformers are connected in parallel or in series with one another, and time axes of waveforms of output voltages of the output windings are synchronized. Thereby, a high-power high voltage is outputted continuously, stably, and safely from both ends of the output windings connected in parallel or in series.
    Type: Application
    Filed: March 25, 2011
    Publication date: September 29, 2011
    Applicant: TOHOKU RICOH CO., LTD.
    Inventor: Hisahiro Kamata