Patents by Inventor Naohiro Kumagai
Naohiro Kumagai 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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Patent number: 9811046Abstract: An image forming apparatus includes a rotatable image bearer, a toner image forming device, a transfer device, a transfer bias power source, and a cleaner. The toner image forming device is to form a toner image on the image bearer. The transfer device contacts a surface of the image bearer to form a transfer nip between the transfer device and the image bearer. The transfer bias power source is to output a transfer bias to transfer the toner image from the image bearer onto a recording medium in the transfer nip. The cleaner is disposed downstream from the transfer nip in a direction of rotation of the image bearer, to electrostatically attract and remove toner from the surface of the image bearer to a surface of the cleaner. The transfer bias includes an alternating current component.Type: GrantFiled: June 22, 2016Date of Patent: November 7, 2017Assignee: Ricoh Company, Ltd.Inventors: Yuuji Wada, Naohiro Kumagai, Seiichi Kogure, Junpei Fujita, Kazuki Yogosawa, Kenji Sugirua, Takehide Mizutani, Tatsuya Ohsugi, Hiroyoshi Haga, Hirokazu Ishii
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Patent number: 9811036Abstract: An endless rotatable belt device including an endless rotatable belt, a scale tape bonded on the belt, at least one optical sensor to detect a scale pattern, and auxiliary tape to cover at least one of the first end and the second end of the scale tape of the belt. The scale tape has a first end and a second end and includes at least one scale pattern. The auxiliary tape has a lower surface friction coefficient than the surface friction coefficient of the scale tape.Type: GrantFiled: September 19, 2016Date of Patent: November 7, 2017Assignee: Ricoh Company, Ltd.Inventors: Junpei Fujita, Kenji Sugiura, Yuuji Wada, Hiroyoshi Haga, Seiichi Kogure, Naohiro Kumagai, Kazuki Yogosawa
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Patent number: 9766575Abstract: An image forming apparatus, including an image bearer configured to bear a toner image; a transfer device disposed opposing to the image bearer; and a transfer bias power source. The transfer bias power source is configured to output a transfer bias to transfer the toner image onto a recording medium. The transfer bias is a superimposed bias that cyclically alternates between a transfer-directional bias to transfer the toner image from the image bearer onto the recording medium and an opposite-directional bias in an opposite direction of the transfer direction. A ratio of a time period of application of the opposite-directional bias to a total time period of one cycle of the output transfer bias is greater than 50%. The transfer bias power source changes a value of a direct current voltage in the superimposed bias according to a linear velocity of the image bearer.Type: GrantFiled: May 2, 2016Date of Patent: September 19, 2017Assignee: Ricoh Company, Ltd.Inventors: Tatsuya Ohsugi, Kenji Sugiura, Hirokazu Ishii, Hiroyoshi Haga, Yuuji Wada, Takehide Mizutani, Naoto Kochi, Naohiro Kumagai, Seiichi Kogure, Junpei Fujita, Kazuki Yogosawa
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Publication number: 20170242371Abstract: An image forming apparatus includes a belt-shaped image bearer, a transferer, a guide, two rotators, and a support. The image bearer has an image bearing surface to bear an image thereon. The transferer forms a transfer section between the transferer and the image hearer, to transfer the image onto a recording medium. The guide is disposed upstream from the transfer section in a delivery direction of the recording medium, to guide the recording medium toward the transfer section. The two rotators are disposed upstream from the transfer section in a moving direction of the image bearer and in contact with a non-image bearing surface of the image bearer opposite to the image bearing surface, a first rotator being closer to the transfer section than a second rotator. The support supports the first rotator and the guide and adjusts a position of the first rotator and a position of the guide.Type: ApplicationFiled: May 10, 2017Publication date: August 24, 2017Inventors: Seiichi KOGURE, Naohiro KUMAGAI, Junpei FUJITA, Kazuki YOGOSAWA, Tatsuya OHSUGI, Kenji SUGIURA, Yuuji WADA, Takehide MIZUTANI
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Patent number: 9740156Abstract: An image forming apparatus includes a toner image forming unit, a nip formation member, a transfer power source, an information acquisition device, and a controller. The information acquisition device acquires specific information that specifies whether a recording sheet as a transfer target of a toner image is an uneven surface sheet having an uneven surface. The controller outputs a bias including a superimposed voltage, in which an alternating current (AC) voltage is superimposed on a direct current (DC) voltage, as a transfer bias from the transfer power source when the specific information acquired by the information acquisition device is not information corresponding to the uneven surface sheet and to output a bias including only the DC voltage as the transfer bias from the transfer power source when the specific information is the information corresponding to the uneven surface sheet.Type: GrantFiled: March 16, 2016Date of Patent: August 22, 2017Assignee: Ricoh Company, Ltd.Inventors: Yuuji Wada, Hiroyoshi Haga, Naohiro Kumagai, Seiichi Kogure, Junpei Fujita, Kazuki Yogosawa, Kenji Sugiura, Takehide Mizutani, Tatsuya Ohsugi, Hirokazu Ishii
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Publication number: 20170235258Abstract: An improved image forming apparatus includes an image bearer, a nip forming member, a transfer power source, and a controller. The controller switches a transfer mode between a first mode to transfer the toner image onto a first type sheet having a surface smoothness higher than a surface smoothness of a second type sheet and a second mode to transfer the toner image onto the second type sheet. The controller controls the transfer power source to output the transfer bias having an opposite-peak duty of greater than or equal to 50% that is a duty on the side of the opposite-peak value in the first mode. The controller controls the transfer power source to output the transfer bias having an opposite-peak duty of less than 50%, which is different from the opposite-peak duty of the first mode, in the second mode.Type: ApplicationFiled: February 8, 2017Publication date: August 17, 2017Inventors: Yuuji WADA, Naoto KOCHI, Hiroki NAKAMATSU, Kazuki YOGOSAWA, Takahiro SUZUKI, Shinya TANAKA, Kenji SUGIURA, Naohiro KUMAGAI, Seiichi KOGURE, Junpei FUJITA, Hirokazu ISHII, Takehide MIZUTANI, Atsushi NAGATA, Keigo NAKAMURA
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Publication number: 20170235257Abstract: An image forming apparatus includes an image bearer to bear a toner image, a nip forming member contacting the image bearer to form a transfer nip, and a transfer power source. The transfer bias has a transfer peak value to electrostatically move toner from the image bearer to the recording sheet and an opposite-peak value to electrostatically move less toner from the image bearer to the recording sheet than the transfer peak value. An opposite-peak duty of the transfer bias is less than 50%. The opposite-peak duty is tr/T×100% where T is one cycle of the transfer bias and tr is a time period during which the transfer bias is on a side of the opposite-peak value relative to an offset voltage of the transfer bias in the one cycle T.Type: ApplicationFiled: February 14, 2017Publication date: August 17, 2017Inventors: Naoto KOCHI, Hirokazu ISHII, Seiichi KOGURE, Naohiro KUMAGAI, Kenji SUGIURA, Shinya TANAKA, Hiroki NAKAMATSU, Yuuji WADA, Junpei FUJITA, Takahiro SUZUKI, Kazuki YOGOSAWA, Atsushi NAGATA
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Patent number: 9720364Abstract: An image forming apparatus includes an image bearer having an image bearing face to bear an image thereon; a transferer disposed opposing the image bearer, to transfer the image from the image bearing face onto a recording medium at a transfer section between the transferer and the image bearer; a first guide disposed upstream from the transfer section in a direction of delivery of the recording medium, to guide the recording medium to the transfer section; and a second guide upstream from the first guide and spaced away from the first guide, to guide the recording medium to the transfer section. Each of the first guide and the second guide extends in a lateral direction perpendicular to the direction of delivery. A leading end of the second guide in the direction of delivery is inclined from one end to the other end of the second guide in the lateral direction.Type: GrantFiled: December 11, 2015Date of Patent: August 1, 2017Assignee: Ricoh Company, Ltd.Inventors: Seiichi Kogure, Naohiro Kumagai, Junpei Fujita, Kazuki Yogosawa, Tatsuya Ohsugi, Kenji Sugiura, Yuuji Wada, Takehide Mizutani, Ryo Hasegawa
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Patent number: 9720355Abstract: An image forming apparatus includes an image bearer, a transfer member, and a power source. The image bearer includes a plurality of layers. The transfer member forms a transfer nip between the image bearer and the transfer member. The power source outputs a transfer bias to transfer a toner image from the image bearer onto a recording sheet in the transfer nip. The transfer bias alternates between a transfer-side bias that causes the toner image to move from the image bearer to the recording sheet, and an opposite-side bias different from the transfer-side bias. A duty ratio of a time period, during which the opposite-side bias is output, relative to one cycle of a waveform, is greater than 50%.Type: GrantFiled: September 14, 2016Date of Patent: August 1, 2017Assignee: Ricoh Company, Ltd.Inventors: Tatsuya Ohsugi, Kenji Sugiura, Jyunya Sakuraba, Hirokazu Ishii, Toshitaka Yamaguchi, Hiroyoshi Haga, Naohiro Kumagai, Seiichi Kogure, Junpei Fujita, Yuuji Wada, Kazuki Yogosawa, Shinya Tanaka, Masayoshi Nakayama
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Patent number: 9696662Abstract: A cleaning device includes an upstream cleaner, an upstream cleaner, and a collection member. The upstream cleaner is configured to remove toner from a surface of a cleaning target. The downstream cleaner is disposed downstream from the upstream cleaner in a direction of movement of the surface of the cleaning target. The downstream cleaner is configured to remove toner from the surface of the cleaning target. The collection member is configured to collect toner from the downstream cleaner.Type: GrantFiled: January 21, 2016Date of Patent: July 4, 2017Assignee: Ricoh Company, Ltd.Inventors: Kazuki Yogosawa, Mitsuru Takahashi, Hiroyoshi Haga, Kenji Sugiura, Naohiro Kumagai, Seiichi Kogure, Kenji Sengoku, Takehide Mizutani, Junpei Fujita, Yuuji Wada, Tatsuya Ohsugi
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Patent number: 9690246Abstract: An image forming apparatus includes a belt-shaped image bearer, a transferer, a guide unit, and a plurality of contact members. The belt-shaped image bearer has an image bearing surface to bear an image thereon. The transferer forms a transfer section between the transferer and the image bearer, to transfer the image onto a recording medium. The guide unit is disposed upstream from the transfer section in a delivery direction of the recording medium, to guide the recording medium toward the transfer section. The plurality of contact members are disposed side by side at positions opposing the guide unit and in contact with a non image bearing surface of the image bearer opposite to the image bearing surface.Type: GrantFiled: December 15, 2015Date of Patent: June 27, 2017Assignee: Ricoh Company, Ltd.Inventors: Seiichi Kogure, Naohiro Kumagai, Junpei Fujita, Kazuki Yogosawa, Tatsuya Ohsugi, Kenji Sugiura, Yuuji Wada, Takehide Mizutani
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Patent number: 9645530Abstract: An image forming apparatus includes an image bearer, a transfer device contacting the image bearer to form a transfer portion, a transfer bias power source, and a controller. A ratio of a time period of application of the opposite-directional bias to a total time period of one cycle of the AC component of the superimposed bias is greater than 50%. A ratio of a value of the DC component of the superimposed bias output within a region ranging from a leading end of the recording medium to a predetermined length to a value of the DC component of the superimposed bias output outside the region is greater than a ratio of a value of the AC component of the superimposed bias output within the region to a value of the AC component of the superimposed bias output outside the region.Type: GrantFiled: April 29, 2016Date of Patent: May 9, 2017Assignee: Ricoh Company, Ltd.Inventors: Naoto Kochi, Kenji Sugiura, Hirokazu Ishii, Hiroyoshi Haga, Yuuji Wada, Takehide Mizutani, Naohiro Kumagai, Junpei Fujita, Tatsuya Ohsugi, Kazuki Yogosawa
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Patent number: 9632461Abstract: An image forming apparatus includes an image bearer, a toner image forming device, a nip forming device, a power source, a controller, and a temperature-and-humidity detector. The toner image forming device forms a toner image on the image bearer. The nip forming device contacts the image bearer to form a transfer nip. The power source outputs a transfer bias, in which an alternating current component is superimposed on a direct current component, to transfer the toner image onto a recording medium interposed in the transfer nip. The temperature-and-humidity detector detects a temperature and humidity. The controller controls the power source to output the transfer bias including the direct current component with a smaller absolute value as at least one of the detected temperature and humidity increases.Type: GrantFiled: December 2, 2015Date of Patent: April 25, 2017Assignee: Ricoh Company, Ltd.Inventors: Kenji Sugiura, Toshitaka Yamaguchi, Hiroyoshi Haga, Hirokazu Ishii, Shinya Tanaka, Takehide Mizutani, Yuuji Wada, Tatsuya Ohsugi, Naohiro Kumagai, Seiichi Kogure, Junpei Fujita, Kazuki Yogosawa
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Publication number: 20170090374Abstract: An endless rotatable belt device including an endless rotatable belt, a scale tape bonded on the belt, at least one optical sensor to detect a scale pattern, and auxiliary tape to cover at least one of the first end and the second end of the scale tape of the belt. The scale tape has a first end and a second end and includes at least one scale pattern. The auxiliary tape has a lower surface friction coefficient than the surface friction coefficient of the scale tape.Type: ApplicationFiled: September 19, 2016Publication date: March 30, 2017Inventors: Junpei FUJITA, Kenji SUGIURA, Yuuji WADA, Hiroyoshi HAGA, Seiichi KOGURE, Naohiro KUMAGAI, Kazuki YOGOSAWA
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Publication number: 20170003630Abstract: An image forming apparatus includes an image bearer, a transfer member, and a power source. The image bearer includes a plurality of layers. The transfer member forms a transfer nip between the image bearer and the transfer member. The power source outputs a transfer bias to transfer a toner image from the image bearer onto a recording sheet in the transfer nip. The transfer bias alternates between a transfer-side bias that causes the toner image to move from the image bearer to the recording sheet, and an opposite-side bias different from the transfer-side bias. A duty ratio of a time period, during which the opposite-side bias is output, relative to one cycle of a waveform, is greater than 50%.Type: ApplicationFiled: September 14, 2016Publication date: January 5, 2017Inventors: Tatsuya OHSUGI, Kenji SUGIURA, Jyunya SAKURABA, Hirokazu ISHII, Toshitaka YAMAGUCHI, Hiroyoshi HAGA, Naohiro KUMAGAI, Seiichi KOGURE, Junpei FUJITA, Yuuji WADA, Kazuki YOGOSAWA, Shinya TANAKA, Masayoshi NAKAYAMA
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Publication number: 20160334738Abstract: An image forming apparatus includes an image bearer, a transfer device contacting the image bearer to form a transfer portion, a transfer bias power source, and a controller. A ratio of a time period of application of the opposite-directional bias to a total time period of one cycle of the AC component of the superimposed bias is greater than 50%. A ratio of a value of the DC component of the superimposed bias output within a region ranging from a leading end of the recording medium to a predetermined length to a value of the DC component of the superimposed bias output outside the region is greater than a ratio of a value of the AC component of the superimposed bias output within the region to a value of the AC component of the superimposed bias output outside the region.Type: ApplicationFiled: April 29, 2016Publication date: November 17, 2016Inventors: Naoto KOCHI, Kenji SUGIURA, Hirokazu ISHll, Hiroyoshi HAGA, Yuuji WADA, Takehide MIZUTANI, Naohiro KUMAGAI, Junpei FUJITA, Tatsuya OHSUGI, Kazuki YOGOSAWA
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Publication number: 20160334739Abstract: An image forming apparatus, including an image bearer configured to bear a toner image; a transfer device disposed opposing to the image bearer; and a transfer bias power source. The transfer bias power source is configured to output a transfer bias to transfer the toner image onto a recording medium. The transfer bias is a superimposed bias that cyclically alternates between a transfer-directional bias to transfer the toner image from the image bearer onto the recording medium and an opposite-directional bias in an opposite direction of the transfer direction. A ratio of a time period of application of the opposite-directional bias to a total time period of one cycle of the output transfer bias is greater than 50%. The transfer bias power source changes a value of a direct current voltage in the superimposed bias according to a linear velocity of the image bearer.Type: ApplicationFiled: May 2, 2016Publication date: November 17, 2016Inventors: Tatsuya OHSUGI, Kenji SUGIURA, Hirokazu ISHII, Hiroyoshi HAGA, Yuuji WADA, Takehide MIZUTANI, Naoto KOCHI, Naohiro KUMAGAI, Seiichi KOGURE, Junpei FUJITA, Kazuki YOGOSAWA
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Publication number: 20160306317Abstract: An image forming apparatus comprises a rotatable image bearer, a toner image forming device, a transfer device, a transfer bias power source, and a cleaner. The toner image forming device is to form a toner image on the image bearer. The transfer device contacts a surface of the image bearer to form a transfer nip between the transfer device and the image bearer. The transfer bias power source is to output a transfer bias to transfer the toner image from the image bearer onto a recording medium in the transfer nip. The cleaner is disposed downstream from the transfer nip in a direction of rotation of the image bearer, to electrostatically attract and remove toner from the surface of the image bearer to a surface of the cleaner. The transfer bias includes an alternating current component.Type: ApplicationFiled: June 22, 2016Publication date: October 20, 2016Inventors: YUUJI WADA, Naohiro Kumagai, Seiichi Kogure, Junpei Fujita, Kazuki Yogosawa, Kenji Sugirua, Takehide Mizutani, Tatsuya Ohsugi, Hiroyoshi Haga, Hirokazu Ishii
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Patent number: 9459564Abstract: An image forming apparatus includes an image bearer, a transfer member, and a power source. The image bearer includes a plurality of layers. The transfer member forms a transfer nip between the image bearer and the transfer member. The power source outputs a transfer bias to transfer a toner image from the image bearer onto a recording sheet in the transfer nip. The transfer bias alternates between a transfer-side bias that causes the toner image to move from the image bearer to the recording sheet, and an opposite-side bias different from the transfer-side bias. A duty ratio of a time period, during which the opposite-side bias is output, relative to one cycle of a waveform, is greater than 50%.Type: GrantFiled: October 13, 2015Date of Patent: October 4, 2016Assignee: Ricoh Company, Ltd.Inventors: Tatsuya Ohsugi, Kenji Sugiura, Jyunya Sakuraba, Hirokazu Ishii, Toshitaka Yamaguchi, Hiroyoshi Haga, Naohiro Kumagai, Seiichi Kogure, Junpei Fujita, Yuuji Wada, Kazuki Yogosawa, Shinya Tanaka, Masayoshi Nakayama
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Patent number: 9454126Abstract: A cleaning device includes a plurality of cleaners. The plurality of cleaners includes at least a first cleaner, a second cleaner, and a third cleaner arranged next to each other in a traveling direction of a cleaning target. The first cleaner is disposed at an extreme upstream end of the traveling direction and supplied with a first voltage having a same polarity as a polarity of a normally-charged toner. The cleaners, other than the first cleaner, disposed downstream from the first cleaner, is supplied with a second voltage having a polarity opposite the polarity of the normally-charged toner.Type: GrantFiled: February 23, 2016Date of Patent: September 27, 2016Assignee: Ricoh Company, Ltd.Inventors: Yusuke Mitani, Kenji Sugiura, Yuuji Wada, Kazuki Yogosawa, Junpei Fujita, Seiichi Kogure, Naohiro Kumagai