Patents by Inventor Keita Maejima

Keita Maejima 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: 10826390
    Abstract: A power supply includes a transformer configured to transform a direct current (DC) voltage and supply an output voltage to a load. The power supply further includes circuitry configured to control the output voltage from the transformer, compare one of an average per unit time of the output voltage and an amplitude value of the output voltage with a threshold in a failure-free state when performing droop control of the output voltage, and determine whether a failure has occurred in at least one of the load and the transformer.
    Type: Grant
    Filed: November 19, 2018
    Date of Patent: November 3, 2020
    Assignee: Ricoh Company, Ltd.
    Inventors: Ryohta Ueba, Keita Maejima
  • Patent number: 10746583
    Abstract: A water content measuring device measures water content of an object to be measured. The water content measuring device includes two plate members that are disposed facing each other, a current generating unit, a measuring unit, and an arithmetic processing unit. The current generating unit generates current supplied between the two plate members. The measuring unit measures electrostatic capacitance generated by the current supplied between the two plate members. The arithmetic processing unit is configured to convert the electrostatic capacitance measured by the measuring unit to water content. Two plate members each have a shape or are disposed such that at least two points on a leading edge of the object enter between the two plate members at different timings in a direction perpendicular to a passing direction in which the object passes through the two plate members.
    Type: Grant
    Filed: April 27, 2018
    Date of Patent: August 18, 2020
    Assignee: RICOH COMPANY, LTD.
    Inventors: Yohei Kushida, Keita Maejima, Hiroshi Okamura, Natsuko Ishizuka, Hayato Fujita, Masaki Tsugawa, Yuji Ikeda
  • Patent number: 10599064
    Abstract: A powder-amount detection device includes a first electrode, a second electrode, a third electrode and a voltage detector with the second electrode adjacent to the first electrode on the powder container and have a smaller surface area than a surface area of the first electrode. The third electrode is on a side opposite to the second electrode with the powder container interposed between the third electrode and each of the first electrode and the second electrode. The voltage detector detects voltages of the first electrode and the second electrode by detecting charging and discharging behaviors of the first electrode and the second electrode when a voltage is applied between the third electrode and each of the first electrode and the second electrode for a short time, and detects the amount of powder in the powder container based on the voltages of the first electrode and the second electrode.
    Type: Grant
    Filed: May 21, 2018
    Date of Patent: March 24, 2020
    Assignee: Ricoh Company, Ltd.
    Inventors: Masahide Yamashita, Taku Kumiya, Yohei Kushida, Takuya Murata, Keita Maejima
  • Patent number: 10571841
    Abstract: A thickness detector includes a rotator having different shape marks, disposed at different positions in a rotation direction; an opposing member disposed opposite the rotator; a detector to detect and output a displacement amount of the rotator or the opposing member in a sheet thickness direction; and a controller. The controller is configured to acquire first output values for one rotation from the detector, in a state without sheet; determine, based on a value output from the detector, whether one of the plurality of marks is detected in a state with the sheet held; acquire a predetermined number of second output values after one of the marks is detected; extract, from the first output values, values corresponding to the second output values, based on the value corresponding to the detected mark; and calculate a sheet thickness based on the second output values and the extracted first output values.
    Type: Grant
    Filed: December 26, 2017
    Date of Patent: February 25, 2020
    Assignee: Ricoh Company, Ltd.
    Inventors: Hayato Fujita, Keita Maejima, Hiroshi Okamura, Masaki Tsugawa, Yuji Ikeda, Yohei Kushida, Emiko Kawarasaki
  • Patent number: 10555373
    Abstract: A heater controller and heater control method is disclosed. The hater controller includes a detector, a determination circuit, a limiting circuit, a selection circuit, and a driving circuit. The detector detects a temperature of the heating object, which is heated by the heater. The determination circuit determines turn-on ratio for the heater for every control cycle of AC voltage, based on the surface temperature of the heating object and a target temperature of the heating object. The limiting circuit limits the turn-on ratio of current control cycle when the control method of previous control cycle is phase control. The selection circuit selects control pattern to control the heater, based on the turn-on ratio, and the driving circuit applies a heater driving signal to the heater.
    Type: Grant
    Filed: August 7, 2015
    Date of Patent: February 4, 2020
    Assignee: RICOH COMPANY, LTD.
    Inventors: Shuntaro Nakayama, Keita Maejima, Ryota Kubokawa
  • Patent number: 10488787
    Abstract: A remaining powder amount detection device includes: a powder moving portion configured to change a distribution of powder in an inner space of a powder container containing the powder; a drive unit configured to drive the powder moving portion; a change value detector configured to detect a change value indicating a positional change of the powder container; and a remaining powder amount detector configured to detect a remaining amount of the powder contained in the powder container, based on the change value. The drive unit is configured to drive the powder moving portion so as to move the powder to near the change value detector. The remaining powder amount detector is configured to detect the remaining amount based on the change value in a state where the powder is moved to near the change value detector.
    Type: Grant
    Filed: May 24, 2018
    Date of Patent: November 26, 2019
    Assignee: RICOH COMPANY, LTD.
    Inventors: Hiroshi Okamura, Masaki Tsugawa, Yuji Ikeda, Natsuko Ishizuka, Hayato Fujita, Yohei Kushida, Keita Maejima
  • Patent number: 10429770
    Abstract: A powder-amount detection device includes an outer electrode, an inner electrode, and a detector. The outer electrode is disposed outside a powder container to be replaceably installed to an image forming apparatus. The inner electrode is disposed inside a powder supply port of the powder container. The detector is configured to apply an electric field between the outer electrode and the inner electrode to detect a capacitance between the outer electrode and the inner electrode.
    Type: Grant
    Filed: June 4, 2018
    Date of Patent: October 1, 2019
    Assignee: Ricoh Company, Ltd.
    Inventors: Taku Kumiya, Masahide Yamashita, Yohei Kushida, Takuya Murata, Keita Maejima
  • Publication number: 20190199211
    Abstract: A power supply includes a transformer configured to transform a direct current (DC) voltage and supply an output voltage to a load. The power supply further includes circuitry configured to control the output voltage from the transformer, compare one of an average per unit time of the output voltage and an amplitude value of the output voltage with a threshold in a failure-free state when performing droop control of the output voltage, and determine whether a failure has occurred in at least one of the load and the transformer.
    Type: Application
    Filed: November 19, 2018
    Publication date: June 27, 2019
    Applicant: Ricoh Company, Ltd.
    Inventors: Ryohta Ueba, Keita Maejima
  • Publication number: 20180348673
    Abstract: A powder-amount detection device includes an outer electrode, an inner electrode, and a detector. The outer electrode is disposed outside a powder container to be replaceably installed to an image forming apparatus. The inner electrode is disposed inside a powder supply port of the powder container. The detector is configured to apply an electric field between the outer electrode and the inner electrode to detect a capacitance between the outer electrode and the inner electrode.
    Type: Application
    Filed: June 4, 2018
    Publication date: December 6, 2018
    Applicant: Ricoh Company, Ltd.
    Inventors: Taku KUMIYA, Masahide YAMASHITA, Yohei KUSHIDA, Takuya MURATA, Keita MAEJIMA
  • Publication number: 20180348664
    Abstract: A remaining powder amount detection device includes: a powder moving portion configured to change a distribution of powder in an inner space of a powder container containing the powder; a drive unit configured to drive the powder moving portion; a change value detector configured to detect a change value indicating a positional change of the powder container; and a remaining powder amount detector configured to detect a remaining amount of the powder contained in the powder container, based on the change value. The drive unit is configured to drive the powder moving portion so as to move the powder to near the change value detector. The remaining powder amount detector is configured to detect the remaining amount based on the change value in a state where the powder is moved to near the change value detector.
    Type: Application
    Filed: May 24, 2018
    Publication date: December 6, 2018
    Inventors: Hiroshi OKAMURA, Masaki TSUGAWA, Yuji IKEDA, Natsuko ISHIZUKA, Hayato FUJITA, Yohei KUSHIDA, Keita MAEJIMA
  • Publication number: 20180341199
    Abstract: A powder-amount detection device includes a first electrode disposed on one side of a powder container to be replaceably installed to an image forming apparatus; a second electrode disposed adjacent to the first electrode and having a smaller surface area than the first electrode, an influence of an amount of powder in the powder container to a capacitance of the second electrode being as small as negligible; a third electrode disposed on a side opposite to the second electrode with the powder container interposed between the third electrode and each of the first electrode and the second electrode; and a voltage detector configured to detect charging and discharging behaviors of the first electrode and the second electrode when a voltage is applied between the third electrode and each of the first electrode and the second electrode for a short time, to detect the amount of powder in the powder container.
    Type: Application
    Filed: May 21, 2018
    Publication date: November 29, 2018
    Applicant: Ricoh Company, Ltd.
    Inventors: Masahide YAMASHITA, Taku KUMIYA, Yohei KUSHIDA, Takuya MURATA, Keita MAEJIMA
  • Publication number: 20180321074
    Abstract: A water content measuring device measures water content of an object to be measured. The water content measuring device includes two plate members that are disposed facing each other, a current generating unit, a measuring unit, and an arithmetic processing unit. The current generating unit generates current supplied between the two plate members. The measuring unit measures electrostatic capacitance generated by the current supplied between the two plate members. The arithmetic processing unit is configured to convert the electrostatic capacitance measured by the measuring unit to water content. Two plate members each have a shape or are disposed such that at least two points on a leading edge of the object enter between the two plate members at different timings in a direction perpendicular to a passing direction in which the object passes through the two plate members.
    Type: Application
    Filed: April 27, 2018
    Publication date: November 8, 2018
    Inventors: Yohei KUSHIDA, Keita Maejima, Hiroshi Okamura, Natsuko Ishizuka, Hayato Fujita, Masaki Tsugawa, Yuji Ikeda
  • Publication number: 20180239285
    Abstract: A thickness detector includes a rotator having different shape marks, disposed at different positions in a rotation direction; an opposing member disposed opposite the rotator; a detector to detect and output a displacement amount of the rotator or the opposing member in a sheet thickness direction; and a controller. The controller is configured to acquire first output values for one rotation from the detector, in a state without sheet; determine, based on a value output from the detector, whether one of the plurality of marks is detected in a state with the sheet held; acquire a predetermined number of second output values after one of the marks is detected; extract, from the first output values, values corresponding to the second output values, based on the value corresponding to the detected mark; and calculate a sheet thickness based on the second output values and the extracted first output values.
    Type: Application
    Filed: December 26, 2017
    Publication date: August 23, 2018
    Applicant: Ricoh Company, Ltd
    Inventors: Hayato Fujita, Keita Maejima, Hiroshi Okamura, Masaki Tsugawa, Yuji Ikeda, Yohei Kushida, Emiko Kawarasaki
  • Patent number: 10029871
    Abstract: An image forming apparatus is provided that forms an image on a sheet material based on a sheet material setting relating to the sheet material. The image forming apparatus includes an accepting unit configured to accept a selection of a sheet material type, a thickness measurement unit configured to measure a thickness of the sheet material, and a setting determination unit configured to determine the sheet material setting that relates to the thickness of the sheet material based on the sheet material type accepted by the accepting unit and the thickness of the sheet material measured by the thickness measurement unit.
    Type: Grant
    Filed: May 9, 2017
    Date of Patent: July 24, 2018
    Assignee: Ricoh Company, Ltd.
    Inventors: Keita Maejima, Shingo Nishizaki, Yuji Ikeda, Takuya Murata, Kazuho Satoh
  • Publication number: 20170336748
    Abstract: An image forming apparatus is provided that forms an image on a sheet material based on a sheet material setting relating to the sheet material. The image forming apparatus includes an accepting unit configured to accept a selection of a sheet material type, a thickness measurement unit configured to measure a thickness of the sheet material, and a setting determination unit configured to determine the sheet material setting that relates to the thickness of the sheet material based on the sheet material type accepted by the accepting unit and the thickness of the sheet material measured by the thickness measurement unit.
    Type: Application
    Filed: May 9, 2017
    Publication date: November 23, 2017
    Applicant: Ricoh Company, Ltd.
    Inventors: Keita MAEJIMA, Shingo NISHIZAKI, Yuji IKEDA, Takuya MURATA, Kazuho SATOH
  • Patent number: 9541867
    Abstract: An image forming apparatus includes a fixing device to fix an image on a recording medium by heating the recording medium, multiple heat storing devices to store heat generated at the fixing device, an electric generating element to generate power by converting the heat into power, and a switch to switch connection and disconnection between the electric generating element and at least one of the multiple heat storing devices.
    Type: Grant
    Filed: August 31, 2015
    Date of Patent: January 10, 2017
    Assignee: Rioch Company, Ltd.
    Inventors: Homare Ehara, Takaaki Shirai, Norikazu Okada, Tomoyuki Yamashita, Ryohta Kubokawa, Takuma Kasai, Keita Maejima
  • Patent number: 9429909
    Abstract: An image forming apparatus includes a heat-generating component, a power generation device including a thermoelectric element, a heat radiation device, a cooling device, a temperature detector that detects a temperature increase of the heat-generating component, and a controller. The heat radiation device includes a first radiator plate interposed between the heat-generating component and a surface of the thermoelectric element and a second radiator plate attached to another surface of the thermoelectric element. The cooling device cools the first radiator plate. The controller controls operations of the cooling device and the power generation device by operating the cooling device if the detected temperature increase reaches at least a predetermined threshold value, and causing the power generation device to generate power without operating the cooling device to cool the first radiator plate passively if the detected temperature increase falls below the predetermined threshold value.
    Type: Grant
    Filed: December 22, 2014
    Date of Patent: August 30, 2016
    Assignee: RICOH COMPANY, LTD.
    Inventors: Takaaki Shirai, Satoru Tao, Takuma Kasai, Norikazu Okada, Homare Ehara, Keita Maejima, Tomoyuki Yamashita, Ryohta Kubokawa
  • Patent number: 9389573
    Abstract: An image forming apparatus includes a heat generator configured to generate heat in the image forming apparatus; a converter including a capacitor to convert AC power supplied from an external power supply into DC power for a load unit; a thermoelectric transducer configured to convert the generated heat into DC power for the load unit; a detector configured to detect a voltage of the AC power; and a controller configured to cause the converter to continue supplying the DC power to the load unit when a first elapsed time elapsed since the detected voltage drops below a rated voltage is shorter than a first time period shorter than an upper limit of a period of time over which the capacitor is dischargeable, and cause the thermoelectric transducer to supply the DC power to the load unit when the first elapsed time exceeds the first time period.
    Type: Grant
    Filed: June 22, 2015
    Date of Patent: July 12, 2016
    Assignee: RICOH COMPANY, LIMITED
    Inventors: Norikazu Okada, Takaaki Shirai, Takuma Kasai, Keita Maejima, Tomoyuki Yamashita, Ryohta Kubokawa, Satoru Tao, Homare Ehara
  • Patent number: 9335683
    Abstract: A fixing device includes a pressure rotator pressed against a fixing rotator to form a fixing nip therebetween, through which a recording medium bearing a toner image is conveyed. A first heater is disposed opposite and heats a first heated span on the fixing rotator spanning in an axial direction thereof. A second heater is disposed opposite and heats a second heated span on the fixing rotator spanning in the axial direction thereof. A temperature sensor unit is disposed opposite an outer circumferential surface of the fixing rotator and includes a first temperature detection element to detect a first temperature of the first heated span on the outer circumferential surface of the fixing rotator and a second temperature detection element to detect a second temperature of the second heated span on the outer circumferential surface of the fixing rotator.
    Type: Grant
    Filed: March 9, 2015
    Date of Patent: May 10, 2016
    Assignee: Ricoh Company, Ltd.
    Inventors: Yasunori Ishigaya, Keita Maejima
  • Publication number: 20160077475
    Abstract: An image forming apparatus includes a fixing device to fix an image on a recording medium by heating the recording medium, multiple heat storing devices to store heat generated at the fixing device, an electric generating element to generate power by converting the heat into power, and a switch to switch connection and disconnection between the electric generating element and at least one of the multiple heat storing devices.
    Type: Application
    Filed: August 31, 2015
    Publication date: March 17, 2016
    Applicant: Ricoh Company, Ltd.
    Inventors: Homare EHARA, Takaaki SHIRAI, Norikazu OKADA, Tomoyuki YAMASHITA, Ryohta KUBOKAWA, Takuma KASAI, Keita MAEJIMA