Patents by Inventor Tadanobu Yoshikawa
Tadanobu Yoshikawa 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: 8962133Abstract: An object of the present invention is to provide: an electrophotographic member which enhances image quality, prevents the lowering of a grade of an image even when images have been repeatedly output, and can remarkably enhance the stability of the grade of the image; an intermediate transfer member; and an image forming apparatus. The electrophotographic member includes a base layer and a surface layer, wherein the surface layer has a binder resin, perfluoropolymer fine particles, a fluorocarbon resin dispersing agent and a particular fluorine compound, wherein the perfluoropolymer fine particle has a fluorine compound carried on its surface.Type: GrantFiled: December 5, 2012Date of Patent: February 24, 2015Assignee: Canon Kabushiki KaishaInventors: Koichi Sato, Naoto Kameyama, Kenji Onuma, Koichi Nakamura, Tadanobu Yoshikawa, Hiroshi Tominaga, Akira Watanabe, Yasushi Shimizu, Rieko Sakamoto
-
Publication number: 20130017002Abstract: The typical configuration of the present invention includes a developer layer restriction member (41) for restricting a developer amount held on a rotatable development sleeve (4c) which carries a developer and conveys the developer to a development region opposite to a photoconductor drum (1), the developer being made by mixing a non-magnetic toner and a magnetic carrier. The present invention includes a substrate resin plate made of a resin, and a resin hard coat layer (41b) disposed on a surface of the developer layer restriction member (41), the resin hard coat layer being made by coating the substrate resin plate with a resin which is harder than the resin of the substrate resin plate.Type: ApplicationFiled: July 3, 2012Publication date: January 17, 2013Applicant: CANON KABUSHIKI KAISHAInventor: Tadanobu Yoshikawa
-
Patent number: 7805089Abstract: An image forming apparatus performs a control sequence in which an AC voltage having a peak-to-peak voltage is applied to a charging member so that a relationship between an absolute value of a surface potential of an image bearing member at a portion under a transfer residual toner remaining on the image bearing member which has been electrically charged by the charging member during non-image formation and an absolute value of a surface potential of a developer carrying member is reversed with respect to a relationship between these absolute values during image formation.Type: GrantFiled: December 15, 2009Date of Patent: September 28, 2010Assignee: Canon Kabushiki KaishaInventor: Tadanobu Yoshikawa
-
Patent number: 7756446Abstract: A pulse-like DC voltage is applied from two power sources to transfer residual toner uniformizing means and toner charge amount control means, respectively, to expel transfer residual toner deposited on these means from these means onto a photosensitive drum. In a low humidity environment, the number of application of the DC voltage is increased so as to sufficiently expel the transfer residual toner because the transfer residual toner is less liable to be expelled even when the pulse-like DC voltage is applied to the above two means in the low humidity environment in which an absolute moisture content in atmosphere is small and electrical resistances at portions of a photosensitive drum contacting the above two means.Type: GrantFiled: April 8, 2008Date of Patent: July 13, 2010Assignee: Canon Kabushiki KaishaInventor: Tadanobu Yoshikawa
-
Publication number: 20100092197Abstract: An image forming apparatus performs a control sequence in which an AC voltage having a peak-to-peak voltage is applied to a charging member so that a relationship between an absolute value of a surface potential of an image bearing member at a portion under a transfer residual toner remaining on the image bearing member which has been electrically charged by the charging member during non-image formation and an absolute value of a surface potential of a developer carrying member is reversed with respect to a relationship between these absolute values during image formation.Type: ApplicationFiled: December 15, 2009Publication date: April 15, 2010Applicant: CANON KABUSHIKI KAISHAInventor: Tadanobu Yoshikawa
-
Patent number: 7657197Abstract: An image forming apparatus performs a control sequence in which an AC voltage having a peak-to-peak voltage is applied to a charging member so that a relationship between an absolute value of a surface potential of an image bearing member at a portion under a transfer residual toner remaining on the image bearing member which has been electrically charged by the charging member during non-image formation and an absolute value of a surface potential of a developer carrying member is reversed with respect to a relationship between these absolute values during image formation.Type: GrantFiled: November 29, 2007Date of Patent: February 2, 2010Assignee: Canon Kabushiki KaishaInventor: Tadanobu Yoshikawa
-
Publication number: 20080193153Abstract: A pulse-like DC voltage is applied from two power sources to transfer residual toner uniformizing means and toner charge amount control means, respectively, to expel transfer residual toner deposited on these means from these means onto a photosensitive drum. In a low humidity environment, the number of application of the DC voltage is increased so as to sufficiently expel the transfer residual toner because the transfer residual toner is less liable to be expelled even when the pulse-like DC voltage is applied to the above two means in the low humidity environment in which an absolute moisture content in atmosphere is small and electrical resistances at portions of a photosensitive drum contacting the above two means.Type: ApplicationFiled: April 8, 2008Publication date: August 14, 2008Applicant: CANON KABUSHIKI KAISHAInventor: Tadanobu YOSHIKAWA
-
Publication number: 20080131153Abstract: An image forming apparatus performs a control sequence in which an AC voltage having a peak-to-peak voltage is applied to a charging member so that a relationship between an absolute value of a surface potential of an image bearing member at a portion under a transfer residual toner remaining on the image bearing member which has been electrically charged by the charging member during non-image formation and an absolute value of a surface potential of a developer carrying member is reversed with respect to a relationship between these absolute values during image formation.Type: ApplicationFiled: November 29, 2007Publication date: June 5, 2008Applicant: CANON KABUSHIKI KAISHAInventor: Tadanobu Yoshikawa
-
Patent number: 7383004Abstract: A pulse-like DC voltage is applied from two power sources to transfer residual toner uniformizing means and toner charge amount control means, respectively, to expel transfer residual toner deposited on these means from these means onto a photosensitive drum. In a low humidity environment, the number of application of the DC voltage is increased so as to sufficiently expel the transfer residual toner because the transfer residual toner is less liable to be expelled even when the pulse-like DC voltage is applied to the above two means in the low humidity environment in which an absolute moisture content in atmosphere is small and electrical resistances at portions of a photosensitive drum contacting the above two means.Type: GrantFiled: December 14, 2005Date of Patent: June 3, 2008Assignee: Canon Kabushiki KaishaInventor: Tadanobu Yoshikawa
-
Publication number: 20060140653Abstract: A pulse-like DC voltage is applied from two power sources to transfer residual toner uniformizing means and toner charge amount control means, respectively, to expel transfer residual toner deposited on these means from these means onto a photosensitive drum. In a low humidity environment, the number of application of the DC voltage is increased so as to sufficiently expel the transfer residual toner because the transfer residual toner is less liable to be expelled even when the pulse-like DC voltage is applied to the above two means in the low humidity environment in which an absolute moisture content in atmosphere is small and electrical resistances at portions of a photosensitive drum contacting the above two means.Type: ApplicationFiled: December 14, 2005Publication date: June 29, 2006Applicant: Canon Kabushiki KaishaInventor: Tadanobu Yoshikawa
-
Patent number: 6952546Abstract: A image forming apparatus includes an image bearing member to be moved rotationally, charging means for electrically charging the image bearing member and toner remaining on the image bearing member, electrostatic latent image forming means for forming an electrostatic latent image on the image bearing member charged by the charging means, developing means for visualizing the electrostatic latent image while recovering the toner remaining on the image bearing member, toner charging means which is disposed upstream from the charging means in a rotational direction of the image bearing member and is to be supplied with a voltage of a polarity identical to that of a voltage to be applied to the charging means to electrically charge the toner remaining on the image bearing member, recording means for recording an operation history of the image forming apparatus, and control means for controlling the voltage to be supplied to the toner charging means on the basis of the operation history of the image forming apparType: GrantFiled: September 24, 2003Date of Patent: October 4, 2005Assignee: Canon Kabushiki KaishaInventor: Tadanobu Yoshikawa
-
Patent number: 6950620Abstract: An image forming apparatus including: an image bearing member; an electrifying unit for electrifying the image bearing member at a contact portion in order to form an electrostatic image on the image bearing member, a voltage, in which a direct-current voltage and an alternating-current voltage are superimposed on each other, being applied to the electrifying unit; and a developing unit for developing the electrostatic image on the image bearing member using toner; where after a toner image on the image bearing member is transferred onto a transferring medium, residual toner residing on the image bearing member is carried to the contact portion in accordance with rotation of the image bearing member, and a peak to peak voltage of the alternating-current voltage applied to the electrifying unit in order to discharge the residual toner adhering to the electrifying unit to the image bearing member during a certain period of non-image forming is set so as to be higher than a peak to peak voltage applied during imType: GrantFiled: August 30, 2002Date of Patent: September 27, 2005Assignee: Canon Kabushiki KaishaInventors: Tadanobu Yoshikawa, Motoki Adachi
-
Publication number: 20040131385Abstract: A image forming apparatus includes an image bearing member to be moved rotationally, charging means for electrically charging the image bearing member and toner remaining on the image bearing member, electrostatic latent image forming means for forming an electrostatic latent image on the image bearing member charged by the charging means, developing means for visualizing the electrostatic latent image while recovering the toner remaining on the image bearing member, toner charging means which is disposed upstream from the charging means in a rotational direction of the image bearing member and is to be supplied with a voltage of a polarity identical to that of a voltage to be applied to the charging means to electrically charge the toner remaining on the image bearing member, recording means for recording an operation history of the image forming apparatus, and control means for controlling the voltage to be supplied to the toner charging means on the basis of the operation history of the image forming apparType: ApplicationFiled: September 24, 2003Publication date: July 8, 2004Applicant: Canon Kabushiki KaishaInventor: Tadanobu Yoshikawa
-
Patent number: 6744994Abstract: An image forming apparatus includes an image bearing member, a first charging member for charging a residual developer on the image bearing member, a second charging member for charging the residual developer, an environmental condition detector, and a controller. The first charging member is disposed downstream of the transferring device and up stream of the charger, with respect to a movement direction of the image bearing member. A voltage having a polarity opposite to a polarity of the developer is applied to the first charging member. The second charging member is disposed downstream of the first charging member and upstream of the charger. A voltage having a polarity like a polarity of the developer is applied to the second charging member. The controller, in accordance with an output of the detector, controls at least one of the voltages applied to the first and second charging members.Type: GrantFiled: September 4, 2002Date of Patent: June 1, 2004Assignee: Canon Kabushiki KaishaInventors: Tadanobu Yoshikawa, Yasunari Watanabe, Motoki Adachi
-
Publication number: 20030147659Abstract: An image forming apparatus includes an image bearing member; charging means for electrically charging the image bearing member; developing means for developing an electrostatic latent image formed on the image bearing member with a developer into a developed image; transferring means for transferring the developed image from the image bearing member onto an image receiving member; a first developer charging member for electrically charging a residual developer on the image bearing member, the first developer charging member being disposed downstream of the transferring means and upstream of the charging means, with respect to a movement direction of the image bearing member, and the first developer charging member being supplied with a voltage of a polarity opposite a regular polarity of the developer; a second developer charging for electrically charging the residual developer on the image bearing member to the regular polarity of the developer, the second developer charging member being disposed downstreamType: ApplicationFiled: September 4, 2002Publication date: August 7, 2003Applicant: Canon Kabushiki KaishaInventors: Tadanobu Yoshikawa, Yasunari Watanabe, Motoki Adachi
-
Publication number: 20030049048Abstract: An image forming apparatus including: an image bearing member; an electrifying unit for electrifying the image bearing member at a contact portion in order to form an electrostatic image on the image bearing member, a voltage, in which a direct-current voltage and an alternating-current voltage are superimposed on each other, being applied to the electrifying unit; and a developing unit for developing the electrostatic image on the image bearing member using toner; where after a toner image on the image bearing member is transferred onto a transferring medium, residual toner residing on the image bearing member is carried to the contact portion in accordance with rotation of the image bearing member, and a peak to peak voltage of the alternating-current voltage applied to the electrifying unit in order to discharge the residual toner adhering to the electrifying unit to the image bearing member during a certain period of non-image forming is set so as to be higher than a peak to peak voltage applied during imType: ApplicationFiled: August 30, 2002Publication date: March 13, 2003Applicant: Canon Kabushiki KaishaInventors: Tadanobu Yoshikawa, Motoki Adachi
-
Patent number: 6128461Abstract: An image forming apparatus includes a cleaning device having a cleaning blade, including a toner image bearing member for bearing a toner image, a cleaning blade for frictionally removing residual toner remaining on the bearing member after a transferring process, and a device for applying vibration to the cleaning blade. Further, the vibration applied to the cleaning blade has a stead-state waveform. The vibration applying device may be a device for a vibration waveform having a frequency and an amplitude required for providing energy for obtaining a cleaning action, which vibration waveform is to be applied to the cleaning blade.Type: GrantFiled: December 8, 1998Date of Patent: October 3, 2000Assignee: Canon Kabushiki KaishaInventor: Tadanobu Yoshikawa