Patents by Inventor Akira Nagumo

Akira Nagumo 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: 7806501
    Abstract: A common data line serially connects a first dot memory group and a second dot memory group in layout order of driven devices so as to form each pair. First word lines are connected to the first dot memory group. Second word lines are connected to the second dot memory group. A data writing section supplies the correction values for the first dot memory group and the correction values for the second dot memory group while shifting the timing and supplies writing signals to the first word lines and the second word lines at predetermined timing. A chip area is reduced and costs of a driving apparatus is reduced.
    Type: Grant
    Filed: March 30, 2007
    Date of Patent: October 5, 2010
    Assignee: Oki Data Corporation
    Inventor: Akira Nagumo
  • Patent number: 7804338
    Abstract: A drive circuit includes a drive element for driving a driven element; a correction data input section for adjusting a drive current of the driven element; a resistor having an end portion connected to ground; and a control voltage generation section for generating a direction value of the drive current. The control voltage generation section includes a calculation amplifier having a first input terminal for receiving a standard voltage, a second input terminal, and an output terminal; a first conductive type transistor having a first terminal, a second terminal connected to the ground, and a control terminal connected to the output terminal; and a current-mirror circuit including a control side transistor and a follower side transistor. The control side transistor has a current output terminal connected to the first terminal. The follower side transistor has a current output terminal connected to another end portion of the resistor and the second input terminal.
    Type: Grant
    Filed: May 22, 2008
    Date of Patent: September 28, 2010
    Assignee: Oki Data Corporation
    Inventor: Akira Nagumo
  • Publication number: 20100182392
    Abstract: A drive circuit for supplying a drive current to a plurality of driven elements includes a plurality of drive output terminals to be connected to the driven elements. The drive output terminals are arranged with a specific pitch in between in an arrangement direction. The drive circuit further includes a plurality of drive transistors. Each of the drive transistors is arranged in an occupied area with a specific width in the arrangement direction larger than the specific pitch.
    Type: Application
    Filed: January 14, 2010
    Publication date: July 22, 2010
    Inventor: Akira NAGUMO
  • Publication number: 20100123691
    Abstract: A driving circuit includes: pixel driving circuits, each including: a driven element formed of a three-terminal light-emitting element, a control element formed of a three-terminal element and configured to control the driven element, a driving element formed of a three-terminal element and configured to drive the driven element, and a charge holding element configured to hold a charge of the driven element; a first designating circuit configured to output a first designating signal to the control element, the first designating signal designating one of the pixel driving circuits; and a second designating circuit configured to output a second designating signal to the control element, the second designating signal designating a driving state of the driven element.
    Type: Application
    Filed: November 9, 2009
    Publication date: May 20, 2010
    Applicant: OKI DATA CORPORATION
    Inventor: Akira NAGUMO
  • Publication number: 20100124438
    Abstract: A light emitting element array includes a plurality of light emitting elements each having a first terminal, a second terminal, and a third terminal. The light emitting elements are arranged next to each other to form a group. The first terminal receives a drive signal, the second terminal is connected to ground, and the third terminal has a threshold voltage or a threshold current controllable from outside so that the light emitting elements are driven in a time division way.
    Type: Application
    Filed: November 10, 2009
    Publication date: May 20, 2010
    Inventor: Akira NAGUMO
  • Publication number: 20100097437
    Abstract: A driver circuit in an optical print head uses driving transistors to drive a row of light-emitting elements. The gate electrodes of the driving transistors are at least partly oriented so that driving current flows in the channels below the gate electrodes in a direction different from the direction of the row the light-emitting elements. This orientation reduces the temperature dependency of the driving current, so that the optical print head can produce the same high image quality at low ambient temperatures as at room temperature.
    Type: Application
    Filed: October 16, 2009
    Publication date: April 22, 2010
    Applicant: OKI DATA CORPORATION
    Inventor: Akira Nagumo
  • Publication number: 20100026214
    Abstract: A light-emitting element array has a plurality of three-terminal light-emitting elements such as light-emitting thyristors with anode, cathode, and gate terminals. The anode terminal of each light-emitting element is connected to a driving circuit. The cathode terminal is grounded. The gate terminals of at least some of the three-terminal light-emitting elements are driven from a common buffer, and within this group of three-terminal light-emitting elements, the anode terminals are driven individually. This enables the array of three-terminal light-emitting elements to be driven in essentially the same way as an array of two-terminal light-emitting elements, but without the need for large power transistors between the cathode terminals and ground.
    Type: Application
    Filed: July 29, 2009
    Publication date: February 4, 2010
    Applicant: OKI DATA CORPORATION
    Inventor: Akira Nagumo
  • Publication number: 20090295901
    Abstract: A light-emitting element array comprises: a resistor connected at a first end to a driving unit; and a plurality of light-emitting elements, each of the plurality of light-emitting elements comprising a three-terminal switching element having a first terminal, a second terminal, and a third terminal, the first terminal in each of the plurality of light-emitting elements being connected to a second end of the resistor, the second terminal in each of the plurality of light-emitting elements being connected to ground, and the third terminal in each of the plurality of light-emitting elements being connected to a control circuit.
    Type: Application
    Filed: May 26, 2009
    Publication date: December 3, 2009
    Applicant: OKI Data Corporation
    Inventor: Akira Nagumo
  • Publication number: 20090243512
    Abstract: A drive circuit includes a drive element for supplying a drive current to a driven element; a control voltage generation circuit for outputting a control voltage to the drive element to generate the drive current through inputting a reference voltage; and a switch section for shutting down the reference voltage when the driven element is not driven so that the control voltage decreases to a level not to generate the drive current.
    Type: Application
    Filed: February 26, 2009
    Publication date: October 1, 2009
    Inventor: Akira Nagumo
  • Publication number: 20090237483
    Abstract: A drive circuit is provided for supplying a drive current to drive a plurality of driven elements each having two main electrodes. The drive circuit includes a switch circuit for receiving a drive signal; and a constant voltage circuit connected to the switch circuit for adjusting the drive current at a constant level.
    Type: Application
    Filed: February 26, 2009
    Publication date: September 24, 2009
    Inventor: Akira Nagumo
  • Publication number: 20090167836
    Abstract: A light emitting apparatus includes optical thyristors, a driver circuit that supplies a drive current to the thyristors so that the thyristors emit light, and a control circuit that controls the thyristors. Each thyristor includes an anode, a cathode connected to the ground, and a gate. The thyristor emits light when the drive current flows therethrough. The control circuit controls the gate, causing a control current to flow from the anode to the gate to turn on the thyristors. The control circuit applies a control voltage to the gate, the control voltage being higher than a voltage appearing across the gate and the cathode when the thyristor remains turned on.
    Type: Application
    Filed: December 22, 2008
    Publication date: July 2, 2009
    Applicant: OKI DATA CORPORATION
    Inventor: Akira NAGUMO
  • Publication number: 20090096493
    Abstract: A driving circuit is supplied capable of preventing excessive overshoot from occurring when electric current of LED rises; preventing degradation of LED that is caused by peak electric current; and preventing the life of LED from shortening.
    Type: Application
    Filed: September 12, 2008
    Publication date: April 16, 2009
    Applicant: OKI DATA CORPORATION
    Inventor: Akira Nagumo
  • Publication number: 20090079364
    Abstract: A driving apparatus is provided that has a plurality of driving circuits formed to correspond to a plurality of driven circuits arranged on a predetermined circuit board, each of the plurality of driving circuits including a driving control unit for driving the corresponding driven circuit, a reference voltage generation unit for generating a reference voltage according to a temperature of the corresponding driven circuit, a control voltage generation unit for generating, based on the reference voltage supplied from the reference voltage generation unit, a control voltage for driving the corresponding driven circuit, the control voltage generation unit supplying the generated control voltage to the driving control unit, a switch device formed between the control voltage generation unit and the reference voltage generation unit, and a switch control unit for driving the switch device based on an inputted control signal, wherein the control voltage generation unit is connected to the reference voltage generatio
    Type: Application
    Filed: September 19, 2008
    Publication date: March 26, 2009
    Applicant: OKI DATA CORPORATION
    Inventor: Akira Nagumo
  • Publication number: 20090066374
    Abstract: A drive circuit is provided for selectively driving a driven element. The drive circuit includes a discharge section for discharging charges, which are accumulated in the driven element when the drive element is turned on, when the drive element is turned off. The drive circuit may include a drive element for driving the driven element. The drive element includes a first ground route disposed separately from a second ground route of the driven element. The first ground route is connected to the second ground route through a connection cable. A diode may be disposed between the connection cable and at least one of the first ground route and the second ground route.
    Type: Application
    Filed: August 21, 2008
    Publication date: March 12, 2009
    Inventor: Akira Nagumo
  • Publication number: 20090066312
    Abstract: A reference voltage generation circuit for outputting a reference voltage from an input voltage includes a specific voltage output unit for outputting a specific voltage from the input voltage; a first circuit section for outputting the reference voltage with a positive temperature property from the specific voltage output from the specific voltage output unit; and a second circuit section for setting a level of the reference voltage output from the first circuit section. The specific voltage output unit is formed of a regulator circuit having a first terminal connected to a power source. The first circuit section is formed of a bi-polar transistor element connected to a second terminal of the regulator circuit. The second circuit section is formed of a resistor connected to the second terminal of the regulator circuit, a collector terminal of the bi-polar transistor element, and an emitter terminal of the bi-polar transistor element.
    Type: Application
    Filed: August 21, 2008
    Publication date: March 12, 2009
    Inventor: Akira Nagumo
  • Publication number: 20090051343
    Abstract: A reference voltage generation circuit includes a current-mirror circuit formed of a plurality of MOS (Metal Oxide Semiconductor) transistors each having a source terminal connected to a power source and a gate terminal connected to with each other; and a plurality of transistors each connected to a drain terminal of each of the MOS transistors of the current-mirror circuit for controlling the current-mirror circuit, so that an output current of the current-mirror circuit is converted to a voltage to be output as a reference voltage. Each of the MOS transistors of the current-mirror circuit has the drain terminal connected to a collector terminal of each of the transistors. Accordingly, when a voltage of the power source varies, it is possible to maintain a collector voltage of each of the transistors at a specific level and a collector current of each of the transistors constant.
    Type: Application
    Filed: July 10, 2008
    Publication date: February 26, 2009
    Inventor: Akira Nagumo
  • Publication number: 20080292344
    Abstract: A drive circuit includes a drive element for driving a driven element; a correction data input section for adjusting a drive current of the driven element; a resistor having an end portion connected to ground; and a control voltage generation section for generating a direction value of the drive current. The control voltage generation section includes a calculation amplifier having a first input terminal for receiving a standard voltage, a second input terminal, and an output terminal; a first conductive type transistor having a first terminal, a second terminal connected to the ground, and a control terminal connected to the output terminal; and a current-mirror circuit including a control side transistor and a follower side transistor. The control side transistor has a current output terminal connected to the first terminal. The follower side transistor has a current output terminal connected to another end portion of the resistor and the second input terminal.
    Type: Application
    Filed: May 22, 2008
    Publication date: November 27, 2008
    Inventor: Akira Nagumo
  • Publication number: 20080239056
    Abstract: A semiconductor device, a print head comprising the semiconductor device and an image forming apparatus comprising the print head are supplied which are able to reduce cost through miniaturizing element size and minishing chip area. The semiconductor device comprises a plurality of light emitting elements; and a shift register circuit that has output terminals respectively corresponding to the plurality of light emitting elements and stores emitting-light instruction data of the light emitting elements, wherein each light emitting element has a first electrode and a second electrode to that lightening electricity of the light emitting element flows, and a third electrode for controlling the light emitting element whether to emit light, the output terminals of the shift register circuit are respectively connected with the third electrodes of the corresponding light emitting element.
    Type: Application
    Filed: March 28, 2008
    Publication date: October 2, 2008
    Applicant: OKI DATA CORPORATION
    Inventor: Akira Nagumo
  • Publication number: 20080166149
    Abstract: A drive device for outputting a drive signal for driving a plurality of light emitting elements time-divisionally, the drive device includes a plurality of input terminals receiving input of a drive control signal for the light emitting elements, and a plurality of output terminals connected to the light emitting elements, for outputting the drive signal based on the drive control signal input into the input terminals, in which the input terminals and the output terminals are arranged substantially in a line.
    Type: Application
    Filed: December 4, 2007
    Publication date: July 10, 2008
    Applicant: OKI DATA CORPORATION
    Inventor: Akira Nagumo
  • Publication number: 20080054979
    Abstract: A level shifting circuit converts an input signal that varies between ground and a first voltage to a shifted signal that varies between ground and a second voltage higher than the first voltage. The level shifting circuit has two branches, in each of which a p-channel transistor and two n-channel transistors are connected in series between the second voltage and ground. When the two n-channel transistors in each branch are turned off, a clamping circuit clamps the node between them to the first voltage level, so that neither n-channel transistor has to withstand the full difference between the second voltage and ground. The level shifting circuit can accordingly be fabricated with transistors of small size, reducing the cost of driving circuits, light-emitting-diode print heads, and image forming apparatus in which the level shifting circuit is used.
    Type: Application
    Filed: August 23, 2007
    Publication date: March 6, 2008
    Applicant: OKI DATA CORPORATION
    Inventor: Akira NAGUMO