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).
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Publication number: 20240096417Abstract: In one embodiment, a semiconductor storage device includes a string that has one end electrically connected to a bit line, and another end electrically connected to a source line, and includes a plurality of memory cells. An operation of writing data to each of a plurality of adjacent first memory cells among the plurality of memory cells is sequentially performed in a direction from a first memory cell on a side of the source line to a first memory cell on a side of the bit line. An operation of reading data from each of the plurality of adjacent first memory cells is performed to allow a current to flow through the string in a first direction from the source line to the bit line.Type: ApplicationFiled: June 20, 2023Publication date: March 21, 2024Applicant: Kioxia CorporationInventors: Hiroshi MAEJIMA, Katsuaki ISOBE, Keita KIMURA
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Patent number: 10826390Abstract: 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: GrantFiled: November 19, 2018Date of Patent: November 3, 2020Assignee: Ricoh Company, Ltd.Inventors: Ryohta Ueba, Keita Maejima
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Patent number: 10746583Abstract: 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: GrantFiled: April 27, 2018Date of Patent: August 18, 2020Assignee: RICOH COMPANY, LTD.Inventors: Yohei Kushida, Keita Maejima, Hiroshi Okamura, Natsuko Ishizuka, Hayato Fujita, Masaki Tsugawa, Yuji Ikeda
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Patent number: 10599064Abstract: 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: GrantFiled: May 21, 2018Date of Patent: March 24, 2020Assignee: Ricoh Company, Ltd.Inventors: Masahide Yamashita, Taku Kumiya, Yohei Kushida, Takuya Murata, Keita Maejima
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Patent number: 10571841Abstract: 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: GrantFiled: December 26, 2017Date of Patent: February 25, 2020Assignee: Ricoh Company, Ltd.Inventors: Hayato Fujita, Keita Maejima, Hiroshi Okamura, Masaki Tsugawa, Yuji Ikeda, Yohei Kushida, Emiko Kawarasaki
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Patent number: 10555373Abstract: 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: GrantFiled: August 7, 2015Date of Patent: February 4, 2020Assignee: RICOH COMPANY, LTD.Inventors: Shuntaro Nakayama, Keita Maejima, Ryota Kubokawa
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Patent number: 10488787Abstract: 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: GrantFiled: May 24, 2018Date of Patent: November 26, 2019Assignee: RICOH COMPANY, LTD.Inventors: Hiroshi Okamura, Masaki Tsugawa, Yuji Ikeda, Natsuko Ishizuka, Hayato Fujita, Yohei Kushida, Keita Maejima
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Patent number: 10429770Abstract: 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: GrantFiled: June 4, 2018Date of Patent: October 1, 2019Assignee: Ricoh Company, Ltd.Inventors: Taku Kumiya, Masahide Yamashita, Yohei Kushida, Takuya Murata, Keita Maejima
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Publication number: 20190199211Abstract: 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: ApplicationFiled: November 19, 2018Publication date: June 27, 2019Applicant: Ricoh Company, Ltd.Inventors: Ryohta Ueba, Keita Maejima
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Publication number: 20180348664Abstract: 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: ApplicationFiled: May 24, 2018Publication date: December 6, 2018Inventors: Hiroshi OKAMURA, Masaki TSUGAWA, Yuji IKEDA, Natsuko ISHIZUKA, Hayato FUJITA, Yohei KUSHIDA, Keita MAEJIMA
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Publication number: 20180348673Abstract: 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: ApplicationFiled: June 4, 2018Publication date: December 6, 2018Applicant: Ricoh Company, Ltd.Inventors: Taku KUMIYA, Masahide YAMASHITA, Yohei KUSHIDA, Takuya MURATA, Keita MAEJIMA
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Publication number: 20180341199Abstract: 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: ApplicationFiled: May 21, 2018Publication date: November 29, 2018Applicant: Ricoh Company, Ltd.Inventors: Masahide YAMASHITA, Taku KUMIYA, Yohei KUSHIDA, Takuya MURATA, Keita MAEJIMA
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Publication number: 20180321074Abstract: 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: ApplicationFiled: April 27, 2018Publication date: November 8, 2018Inventors: Yohei KUSHIDA, Keita Maejima, Hiroshi Okamura, Natsuko Ishizuka, Hayato Fujita, Masaki Tsugawa, Yuji Ikeda
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Publication number: 20180239285Abstract: 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: ApplicationFiled: December 26, 2017Publication date: August 23, 2018Applicant: Ricoh Company, LtdInventors: Hayato Fujita, Keita Maejima, Hiroshi Okamura, Masaki Tsugawa, Yuji Ikeda, Yohei Kushida, Emiko Kawarasaki
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Patent number: 10029871Abstract: 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: GrantFiled: May 9, 2017Date of Patent: July 24, 2018Assignee: Ricoh Company, Ltd.Inventors: Keita Maejima, Shingo Nishizaki, Yuji Ikeda, Takuya Murata, Kazuho Satoh
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Publication number: 20170336748Abstract: 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: ApplicationFiled: May 9, 2017Publication date: November 23, 2017Applicant: Ricoh Company, Ltd.Inventors: Keita MAEJIMA, Shingo NISHIZAKI, Yuji IKEDA, Takuya MURATA, Kazuho SATOH
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Patent number: 9541867Abstract: 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: GrantFiled: August 31, 2015Date of Patent: January 10, 2017Assignee: Rioch Company, Ltd.Inventors: Homare Ehara, Takaaki Shirai, Norikazu Okada, Tomoyuki Yamashita, Ryohta Kubokawa, Takuma Kasai, Keita Maejima
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Patent number: 9429909Abstract: 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: GrantFiled: December 22, 2014Date of Patent: August 30, 2016Assignee: RICOH COMPANY, LTD.Inventors: Takaaki Shirai, Satoru Tao, Takuma Kasai, Norikazu Okada, Homare Ehara, Keita Maejima, Tomoyuki Yamashita, Ryohta Kubokawa
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Patent number: 9389573Abstract: 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: GrantFiled: June 22, 2015Date of Patent: July 12, 2016Assignee: RICOH COMPANY, LIMITEDInventors: Norikazu Okada, Takaaki Shirai, Takuma Kasai, Keita Maejima, Tomoyuki Yamashita, Ryohta Kubokawa, Satoru Tao, Homare Ehara
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Patent number: 9335683Abstract: 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: GrantFiled: March 9, 2015Date of Patent: May 10, 2016Assignee: Ricoh Company, Ltd.Inventors: Yasunori Ishigaya, Keita Maejima