Patents by Inventor Kuniaki Tamagaki
Kuniaki Tamagaki 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: 20240085846Abstract: An image forming apparatus includes a rotatable image bearing member, a developing member, a transfer member, and a brush contacting a surface of the image bearing member in a contact portion downstream of a transfer portion and upstream of a developing portion with respect to a rotational direction of the image bearing member. The toner which is not transferred onto a toner image receiving member is collected by the developing member. In a charging series, the toner is positioned on the same side as a normal charge polarity of the toner relative to the brush. In the contact portion, a maximum value of a contact pressure of 0.7 gf/mm2 or more and 3.5 gf/mm2 or less, a maximum contact area ratio is 18% or more and 74% or less, and a Clark-Evans index of the brush is 1 or more.Type: ApplicationFiled: November 17, 2023Publication date: March 14, 2024Inventors: Takayuki Kanazawa, Nobuo Oshima, Takayoshi Kihara, Kuniaki Tamagaki, Shuhei Tokiwa, Taichi Sato
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Patent number: 11860566Abstract: An image forming apparatus includes a rotatable image bearing member, a developing member, a transfer member, and a brush contacting a surface of the image bearing member in a contact portion downstream of a transfer portion and upstream of a developing portion with respect to a rotational direction of the image bearing member. The toner which is not transferred onto a toner image receiving member is collected by the developing member. In a charging series, the toner is positioned on the same side as a normal charge polarity of the toner relative to the brush. In the contact portion, a maximum value of a contact pressure of 0.7 gf/mm2 or more and 3.5 gf/mm2 or less, a maximum contact area ratio is 18% or more and 74% or less, and a Clark-Evans index of the brush is 1 or more.Type: GrantFiled: December 15, 2022Date of Patent: January 2, 2024Assignee: Canon Kabushiki KaishaInventors: Takayuki Kanazawa, Nobuo Oshima, Takayoshi Kihara, Kuniaki Tamagaki, Shuhei Tokiwa, Taichi Sato
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Publication number: 20230195026Abstract: An image forming apparatus includes a rotatable image bearing member, a developing member, a transfer member, and a brush contacting a surface of the image bearing member in a contact portion downstream of a transfer portion and upstream of a developing portion with respect to a rotational direction of the image bearing member. The toner which is not transferred onto a toner image receiving member is collected by the developing member. In a charging series, the toner is positioned on the same side as a normal charge polarity of the toner relative to the brush. In the contact portion, a maximum value of a contact pressure of 0.7 gf/mm2 or more and 3.5 gf/mm2 or less, a maximum contact area ratio is 18% or more and 74% or less, and a Clark-Evans index of the brush is 1 or more.Type: ApplicationFiled: December 15, 2022Publication date: June 22, 2023Inventors: Takayuki Kanazawa, Nobuo Oshima, Takayoshi Kihara, Kuniaki Tamagaki, Shuhei Tokiwa, Taichi Sato
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Publication number: 20220187734Abstract: An image forming apparatus at least includes: an image bearing member; a developer container; a developer carrying member; and a controller that controls a power source that applies a voltage to the developer carrying member, wherein the developer carrying member has at least a base and a surface layer, the surface layer has an electron donating portion that mainly donates charge to the developer when the developer and the surface layer makes frictional contact to exchange charge and an electron accepting portion that mainly accepts charge from the developer, and the controller applies an AC voltage to the developer carrying member during a period in which an image forming operation is not performed and the developer carrying member is driven, the AC voltage being different from that applied during an image forming period.Type: ApplicationFiled: March 11, 2020Publication date: June 16, 2022Inventors: Yuta Isobe, Kuniaki Tamagaki, Takashi Koyanagi, Akihisa Matsukawa, Ryosuke Kanai, Hiroki Tanaka, Motonari Ito, Kazuhisa Shida, Makoto Fukatsu
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Patent number: 10635018Abstract: An image forming apparatus includes: an image bearing member to rotate; a charging member to charge a surface of the image bearing member; a charging voltage applying portion to apply an alternating-current voltage having a predetermined charging frequency to the charging member; and an exposing portion to perform image exposure and background exposure. A plurality of modes are settable for the image forming apparatus, and the plurality of image forming modes include image forming modes different in a background potential difference which is a potential difference between a surface potential of the image bearing member after the surface of the image bearing member is charged and before the charged surface is exposed by the exposing portion and a surface potential of a portion of the surface of the image bearing member which has been subjected to the background exposure.Type: GrantFiled: February 22, 2019Date of Patent: April 28, 2020Assignee: CANON KABUSHIKI KAISHAInventors: Ryosuke Kanai, Seiichi Shinohara, Kuniaki Tamagaki
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Publication number: 20190265606Abstract: An image forming apparatus includes: an image bearing member to rotate; a charging member to charge a surface of the image bearing member; a charging voltage applying portion to apply an alternating-current voltage having a predetermined charging frequency to the charging member; and an exposing portion to perform image exposure and background exposure. A plurality of modes are settable for the image forming apparatus, and the plurality of image forming modes include image forming modes different in a background potential difference which is a potential difference between a surface potential of the image bearing member after the surface of the image bearing member is charged and before the charged surface is exposed by the exposing portion and a surface potential of a portion of the surface of the image bearing member which has been subjected to the background exposure.Type: ApplicationFiled: February 22, 2019Publication date: August 29, 2019Inventors: Ryosuke Kanai, Seiichi Shinohara, Kuniaki Tamagaki
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Patent number: 10209668Abstract: An image forming apparatus in which a developer bearing member is disposed below a cleaning member, which cleans a charging member, so as to overlap with the cleaning member when viewed in a vertical direction and includes a base body and an elastic layer covering the base body and having a width in a longitudinal direction of the developer bearing member that accommodates the entire region of the cleaning member in the longitudinal direction. In the longitudinal direction, the cleaning member is disposed at a position where the entire region thereof in the longitudinal direction is accommodated in the width of the elastic layer.Type: GrantFiled: April 2, 2018Date of Patent: February 19, 2019Assignee: Canon Kabushiki KaishaInventors: Akihisa Matsukawa, Toshiki Okamura, Kuniaki Tamagaki, Takanori Watanabe, Hiroyoshi Iwayama, Makoto Tokudome, Hideo Kihara, Naoki Hayashi
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Patent number: 10108123Abstract: An image forming apparatus includes an image bearing member, a developer bearing member, a fixing unit including a heating member, a rotary member which is heated by the heating member, and a nip area where the rotary member comes into contact with a sheet, and configured to perform fixing by heating a developer image transferred to the sheet and fixing the developer image to the sheet in the nip area, and a control unit configured to execute, while the fixing is not performed, a mode in which the image bearing member is rotated with the developer bearing member being in a separated position and the heating member is controlled such that a temperature of a portion of a surface of the rotary member, after the rotary member passes through the nip area, is maintained higher than the temperature of the portion during the fixing.Type: GrantFiled: September 22, 2017Date of Patent: October 23, 2018Assignee: Canon Kabushiki KaishaInventors: Motonari Ito, Kuniaki Tamagaki, Makoto Tokudome
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Patent number: 10095150Abstract: An image forming apparatus includes an image bearing member, a charging member, a charging voltage source, an electrostatic image forming portion, a developing device, a developing voltage source, a transfer portion, a transfer voltage source, and a controller. During image formation, the toner remaining on the image bearing member after transfer is collected into the developing device while forming an image. In a cleaning operation performed during non-image formation, while rotating the image bearing member, the controller transfers the toner from the charging member onto the image bearing member, passes the toner through the developing portion in an urged state, reverses a charge polarity of the toner to a normal polarity at a charging portion, and then transfers the toner reversed in charge polarity from the image bearing member onto the developing member at the developing portion to collect the toner in the developing device.Type: GrantFiled: September 10, 2015Date of Patent: October 9, 2018Assignee: Canon Kabushiki KaishaInventors: Takashi Hiramatsu, Yusuke Usui, Kuniaki Tamagaki, Hiroyoshi Iwayama
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Publication number: 20180224799Abstract: An image forming apparatus in which a developer bearing member is disposed below a cleaning member, which cleans a charging member, so as to overlap with the cleaning member when viewed in a vertical direction and includes a base body and an elastic layer covering the base body and having a width in a longitudinal direction of the developer bearing member that accommodates the entire region of the cleaning member in the longitudinal direction. In the longitudinal direction, the cleaning member is disposed at a position where the entire region thereof in the longitudinal direction is accommodated in the width of the elastic layer.Type: ApplicationFiled: April 2, 2018Publication date: August 9, 2018Inventors: Akihisa Matsukawa, Toshiki Okamura, Kuniaki Tamagaki, Takanori Watanabe, Hiroyoshi Iwayama, Makoto Tokudome, Hideo Kihara, Naoki Hayashi
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Patent number: 9971298Abstract: An image forming apparatus in which a developer bearing member is disposed below a cleaning member, which cleans a charging member, so as to overlap with the cleaning member when viewed in a vertical direction and includes a base body and an elastic layer covering the base body and having a width in a longitudinal direction of the developer bearing member that accommodates the entire region of the cleaning member in the longitudinal direction. In the longitudinal direction, the cleaning member is disposed at a position where the entire region thereof in the longitudinal direction is accommodated in the width of the elastic layer.Type: GrantFiled: July 14, 2017Date of Patent: May 15, 2018Assignee: Canon Kabushiki KaishaInventors: Akihisa Matsukawa, Toshiki Okamura, Kuniaki Tamagaki, Takanori Watanabe, Hiroyoshi Iwayama, Makoto Tokudome, Hideo Kihara, Naoki Hayashi
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Publication number: 20180088507Abstract: An image forming apparatus includes an image bearing member, a developer bearing member, a fixing unit including a heating member, a rotary member which is heated by the heating member, and a nip area where the rotary member comes into contact with a sheet, and configured to perform fixing by heating a developer image transferred to the sheet and fixing the developer image to the sheet in the nip area, and a control unit configured to execute, while the fixing is not performed, a mode in which the image bearing member is rotated with the developer bearing member being in a separated position and the heating member is controlled such that a temperature of a portion of a surface of the rotary member, after the rotary member passes through the nip area, is maintained higher than the temperature of the portion during the fixing.Type: ApplicationFiled: September 22, 2017Publication date: March 29, 2018Inventors: Motonari Ito, Kuniaki Tamagaki, Makoto Tokudome
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Patent number: 9910405Abstract: A developing device includes a developer bearing member, a regulating member configured to regulate an amount of the developer borne by the developer bearing member, and a toner seal member being in contact with a peripheral surface of the developer bearing member. The regulating member includes a flexible support member and a blade member supported by the support member and being in contact with the developer bearing member, an end portion of the regulating member more protrudes toward the developer bearing member than a central portion thereof in a rotation axial direction of the developer bearing member. The toner seal member is pressed along the rotation axial direction to the end portion of the regulating member in the rotation axial direction.Type: GrantFiled: September 6, 2016Date of Patent: March 6, 2018Assignee: Canon Kabushiki KaishaInventors: Takanori Watanabe, Akihisa Matsukawa, Kuniaki Tamagaki
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Patent number: 9904202Abstract: In an image forming apparatus configured such that developer remaining on an image bearing member without being transferred to a recording material is moved from the image bearing member to a developer bearing member and then recovered in a developer storage portion 35. When forming a second image on a rear surface of the recording material having a surface on which a first image is fixed with a fixing device, a second potential difference between surface potential of the image bearing member after charging with a charging member when forming the second image and potential of the developer bearing member is less than a first potential difference when forming a first image.Type: GrantFiled: September 8, 2016Date of Patent: February 27, 2018Assignee: CANON KABUSHIKI KAISHAInventors: Akihisa Matsukawa, Kuniaki Tamagaki, Takanori Watanabe
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Publication number: 20180024495Abstract: An image forming apparatus in which a developer bearing member is disposed below a cleaning member, which cleans a charging member, so as to overlap with the cleaning member when viewed in a vertical direction and includes a base body and an elastic layer covering the base body and having a width in a longitudinal direction of the developer bearing member that accommodates the entire region of the cleaning member in the longitudinal direction. In the longitudinal direction, the cleaning member is disposed at a position where the entire region thereof in the longitudinal direction is accommodated in the width of the elastic layer.Type: ApplicationFiled: July 14, 2017Publication date: January 25, 2018Inventors: Akihisa Matsukawa, Toshiki Okamura, Kuniaki Tamagaki, Takanori Watanabe, Hiroyoshi Iwayama, Makoto Tokudome, Hideo Kihara, Naoki Hayashi
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Patent number: 9645537Abstract: An image forming apparatus is provided that includes a light-emitting unit which emits light to an image bearing member which bears a developer image and that detects presence or absence of a developer container storing developer or a shape of the developer container on the basis of the number of electrons discharged from or received by the image bearing member when the light-emitting unit emits the light.Type: GrantFiled: June 4, 2015Date of Patent: May 9, 2017Assignee: Canon Kabushiki KaishaInventors: Kuniaki Tamagaki, Motoki Adachi, Satoshi Sunahara, Takanori Watanabe
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Publication number: 20170075249Abstract: In an image forming apparatus configured such that a developer remaining on an image bearing member 1 without being transferred to a recording material P is moved from the image bearing member to a developer bearing member 31 and then recovered in a developer storage portion 35, when forming a second image on a rear face of the recording material P having a surface on which a first image is fixed with a fixing device 6, a second potential difference between surface potential of the image bearing member 1 after charging with a charging member 2 when forming the second image and potential of the developer bearing member 31 is less than a first potential difference when forming a first image.Type: ApplicationFiled: September 8, 2016Publication date: March 16, 2017Inventors: Akihisa Matsukawa, Kuniaki Tamagaki, Takanori Watanabe
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Publication number: 20170068211Abstract: A developing device includes a developer bearing member, a regulating member configured to regulate an amount of the developer borne by the developer bearing member, and a toner seal member being in contact with a peripheral surface of the developer bearing member. The regulating member includes a flexible support member and a blade member supported by the support member and being in contact with the developer bearing member, an end portion of the regulating member more protrudes toward the developer bearing member than a central portion thereof in a rotation axial direction of the developer bearing member. The toner seal member is pressed along the rotation axial direction to the end portion of the regulating member in the rotation axial direction.Type: ApplicationFiled: September 6, 2016Publication date: March 9, 2017Inventors: Takanori Watanabe, Akihisa Matsukawa, Kuniaki Tamagaki
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Patent number: 9547273Abstract: When an outer diameter of a charging member is defined as Hc, a ratio of the circumferential velocity of the charging member to the circumferential velocity of an image bearing member is defined as Rc, an outer diameter of a developer bearing member is defined as Hd, and a ratio of the circumferential velocity of the developer bearing member to the circumferential velocity of the image bearing member is defined as Rd, the relationship Hc/Rc?Hd/Rd is satisfied.Type: GrantFiled: June 8, 2015Date of Patent: January 17, 2017Assignee: CANON KABUSHIKI KAISHAInventors: Motonari Ito, Motoki Adachi, Satoshi Sunahara, Kuniaki Tamagaki
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Patent number: 9429868Abstract: An image forming apparatus includes a controller that executes a collection sequence to collect developer of opposite polarity adhering to a charging member. The controller executes the collection sequence by setting a first potential difference to allow the developer of opposite polarity to move from the charging member to an image bearing member, setting a second potential difference to allow the developer of opposite polarity to move from the image bearing member to a developer bearing member and to allow the developer of regular polarity to move from the developer bearing member to the image bearing member, setting a third potential difference to not allow the developer of regular polarity to move from the image bearing member to the charging member, and setting a fourth potential difference to allow the developer of regular polarity to move from the image bearing member to the developer bearing member.Type: GrantFiled: August 10, 2015Date of Patent: August 30, 2016Assignee: CANON KABUSHIKI KAISHAInventors: Yusuke Usui, Kuniaki Tamagaki, Akihisa Matsukawa, Takashi Hiramatsu