Patents by Inventor Akihito Ikegawa
Akihito Ikegawa 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: 5402213Abstract: A contact charging device for charging an outer surface of an electrostatic latent image carrier in contact therewith which has a charging member at least partly in contact with the electrostatic latent image carrier, the portion of the charging member in contact with the electrostatic latent image carrier being formed by a layer containing a copolymer of an olefin-type vinyl monomer and a fluorine-contained monomer, and a power supply for applying a charging voltage to the charging member.Type: GrantFiled: November 12, 1993Date of Patent: March 28, 1995Assignee: Minolta Camera Kabushiki KaishaInventors: Akihito Ikegawa, Masaki Asano, Keiko Nagayasu, Masashi Yamamoto
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Patent number: 5376425Abstract: A contact member for controlling an electrostatic state of a surface of a chargeable member includes electrically conductive base members, and flame retardant material included in the base members.Type: GrantFiled: December 17, 1992Date of Patent: December 27, 1994Assignees: Minolta Camera Kabushiki Kaisha, Toeisangyo Co., Ltd.Inventors: Masaki Asano, Shuji Iino, Akihito Ikegawa, Izumi Osawa, Kenzo Tanaka
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Patent number: 5376995Abstract: A contact charger in an electrophotographic image forming apparatus for electrostatically charging a photosensitive, latent image support surface of a rotatably supported photosensitive drum in contact therewith. The contact charger comprises a generally elongated carrier and a charging member carried at a first side edge by the carrier. This charging member has a second side edge opposite to the first side edge which is held in sliding contact with the photosensitive surface over a predetermined contact distance. The charging member has a curved surface of a radius of curvature of 0.02 to 1.0 mm at a side edge portion thereof at which contact of the charging member with the photosensitive surface terminates. A power source for applying a voltage to the charging member is also employed.Type: GrantFiled: October 25, 1993Date of Patent: December 27, 1994Assignee: Minolta Camera Kabushiki KaishaInventors: Masashi Yamamoto, Masaki Asano, Keiko Nagayasu, Akihito Ikegawa
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Patent number: 5371578Abstract: An image forming apparatus includes electrostatic latent image carrier having a moving surface to be charged and contact charging device for selectively applying a first charging voltage and a second charging voltage to the surface to be charged, the second charging voltage having the same polarity as the first charging voltage and having an absolute value smaller than that of the first charging voltage, the first charging voltage being applied to an electrostatic latent image forming region of the surface to be charged, the first charging voltage being changed to the second charging voltage when a region confronting the contact charging device moves from the electrostatic latent image forming region to a non-image portion in accordance with movement of the surface to be charged.Type: GrantFiled: October 18, 1993Date of Patent: December 6, 1994Assignee: Minolta Camera Kabushiki KaishaInventors: Masaki Asano, Shuji Iino, Akihito Ikegawa, Izumi Osawa
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Patent number: 5343223Abstract: An image forming apparatus having a sheet storing unit for storing sheets therein along a bottom of a body of the apparatus, a sheet feeding mechanism for feeding the sheets stored in the sheet storing unit one by one toward a rear side of the body, a sheet path for leading each sheet fed by the sheet feeding mechanism upward, an image forming unit for forming an image on the sheet traveling in the sheet path, and a sheet ejecting unit for ejecting the image-formed sheet toward a front side of the body onto a sheet receiving portion disposed on an upper side of the body. The image forming unit is made as a cartridge containing a photosensitive member, a developing device, a transferring device and a cleaner. The cartridge is mounted in a holder which is movable between a cartridge exchange position and a set position.Type: GrantFiled: November 20, 1991Date of Patent: August 30, 1994Assignee: Minolta Camera Kabushiki KaishaInventors: Yoshio Tohyama, Takayuki Ogawa, Tatsuya Eguchi, Norio Tamada, Satoshi Yoshida, Hirofumi Hasegawa, Hitoshi Sekino, Katsuyuki Taima, Akihito Ikegawa, Kazuyoshi Hara, Yasuhiro Matsuura, Hiroshi Mizuno
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Patent number: 5338895Abstract: A developing apparatus for developing an electrostatic latent image on an electrostatic latent image carrier includes a toner tank for storing toner, a developing roller, toner and a blade for supplying the toner from the toner tank to the developing roller. The apparatus further includes a regulation member having one end portion fixedly supported and the other end portion being slidingly held in contact with the outer surface to define a contacting area. The regulating member is bent at an angle .alpha. outwardly from the outer surface to define a bent portion such that the bent portion is located closely adjacent the developing roller with respect to the contacting area.Type: GrantFiled: February 11, 1993Date of Patent: August 16, 1994Assignee: Minolta Camera Kabushiki KaishaInventors: Akihito Ikegawa, Kouichi Aritomo, Kazuki Tsukamoto, Michiya Yamashita
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Patent number: 5328790Abstract: A photoreceptor for contact charging to be used in an electrophotographic process, which includes an electrically conductive base and a photosensitive layer formed on the base so as to be charged by contact charging, and is characterized in that even when pin holes or photosensitive layer lacking portions in the form of pin holes are present on he photosensitive layer, short-circuiting is safely and positively prevented over a long period. The electrically conductive base further includes a base main body of aluminum alloy having Brinell hardness higher than 40 H.sub.B, and an alumite treatment applied over the surface of the aluminum alloy base main body.Type: GrantFiled: September 23, 1992Date of Patent: July 12, 1994Assignee: Minolta Camera Kabushiki KaishaInventors: Masaki Asano, Shuji Iino, Akihito Ikegawa, Izumi Osawa
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Patent number: 5305061Abstract: An image forming apparatus comprises an image carrier for carrying an electrostatic latent image on its surface, a charging member for charging the image carrier to a predetermined polarity by contacting with the surface of the image carrier, latent image forming means for forming an electrostatic latent image corresponding to image information on the surface of the image carrier charged, and a developing device containing toner including toner particles not less than 90% of which have a shape factor SF-1 expressed by the following equation of not more than 160 and less than 1% of which have a shape factor SF-1 of not less than 170 so as to develop the electrostatic latent image formed on the surface of the image carrier into a toner image:[SF-1]=(L.sup.2 /S).times..pi./4.times.100(in the equation, S is the area indicating the average value of the projected areas of the toner, and L is the maximum length indicating the average value of the maximum lengths at the time of projecting the toner).Type: GrantFiled: December 17, 1991Date of Patent: April 19, 1994Assignee: Minolta Camera Kabushiki KaishaInventors: Masaaki Takama, Junji Machida, Akihito Ikegawa
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Patent number: 5289234Abstract: An image forming apparatus having a detachable imaging cartridge which includes a photosensitive member charged by a charge brush having brush fibers. At least one of the photosensitive member and the charging brush is detachable from the imaging cartridge, and the detachable one is attached to the imaging cartridge through a guide member so that the brush fibers of the charge brush are indented toward a downstream side relative to a predetermined position of the charge brush with respect to the rotational direction of the photosensitive member.Type: GrantFiled: July 22, 1993Date of Patent: February 22, 1994Assignee: Minolta Camera Kabushiki KaishaInventors: Masaki Asano, Shuji Iino, Akihito Ikegawa, Izumi Osawa
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Patent number: 5278614Abstract: A contact charger for charging an image bearing member includes a support member, a flexible film supported by the support member and having a free end adapted to contact the surface of the image bearing member, and a power device for applying a charging voltage to the flexible film wherein the flexible film has an electrically conductive substrate layer and an electrically insulated overcoat layer superposed onto the substrate layer.Type: GrantFiled: April 15, 1993Date of Patent: January 11, 1994Assignee: Minolta Camera Kabushiki KaishaInventors: Akihito Ikegawa, Masaki Asano, Shuji Iino, Izumi Osawa
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Patent number: 5245386Abstract: A contact charging device for charging a moving surface of an electrostatic latent image support member includes a large number of brush hairs contacting the moving surface of the electrostatic latent image support member; a brush restricting member, which is disposed upstream to the brush hairs in a moving direction of the surface of the electrostatic latent image support member and contacts the brush hairs; and a brush holder member holding the brush hair group, the holder member being electrically coupled to a power supply to apply a voltage to the brush hairs.Type: GrantFiled: February 27, 1992Date of Patent: September 14, 1993Assignee: Minolta Camera Kabushiki KaishaInventors: Masaki Asano, Shuji Iino, Akihito Ikegawa, Izumi Osawa
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Patent number: 5243387Abstract: A charging device for charging a surface of an electrostatic latent image support member used in an image forming apparatus. The apparatus has a rotatably disposed roller confronting the electrostatic latent image support member, a cylindrically formed flexible member having a peripheral length longer than that of the roller and loosely mounted therearound, a guide member for biasing the flexible member against the roller to form a slack of the flexible member at a location confronting the electrostatic latent image support member so that the slack of the flexible member is brought into contact with the electrostatic latent image support member, and a power supply for applying a voltage to the flexible member.Type: GrantFiled: December 19, 1991Date of Patent: September 7, 1993Assignee: Minolta Camera Kabushiki KaishaInventor: Akihito Ikegawa
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Patent number: 5241342Abstract: In a printer, in which a fixed brush charger charges a surface of a photosensitive drum to form a charged area to be converted into an electrostatic latent image by an optical system, fine particles having a volumetric mean particle diameter of 5 to 20 .mu.m are supplied to the brush charger, from upstream side, in a moving direction of surface of the photosensitive member, of the charger, the particles being adhered onto the surface of the photosensitive member with an adhesion density of 5 to 1000 pcs/cm.sup.2.Type: GrantFiled: May 26, 1992Date of Patent: August 31, 1993Assignee: Minolta Camera Kabushiki KaishaInventors: Masaki Asano, Shuji Iino, Akihito Ikegawa, Izumi Osawa
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Patent number: 5225878Abstract: An image forming apparatus includes a latent image carrier having a movable surface, and a stationary contact brush charger for electrostatically charging the surface of the latent image carrier in contact therewith during a movement of the carrier surface relative to the brush charger. In this apparatus, the contact time t, during which any arbitrarily chosen point on the carrier surface then moving in one direction is held in contact with the brush charger, and the electric resistance R of each of the brush bristles forming the brush charger are chosen such that the product of the contact time t multiplied by the common logarithm of the electric resistance R, i.e., (t.times.log.sub.10 R), is within the range of 0.9 to 4.6.Type: GrantFiled: September 18, 1992Date of Patent: July 6, 1993Assignee: Minolta Camera Kabushiki KaishaInventors: Masaki Asano, Shuji Iino, Akihito Ikegawa, Izumi Osawa
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Patent number: 5192974Abstract: A contact charger for charging an image bearing member comprises a support member, a flexible film supported at a side end by the support member and having a free end adapted to contact the surface of the image bearing member, and power device for applying charging voltage to the flexible film.Type: GrantFiled: January 30, 1992Date of Patent: March 9, 1993Assignee: Minolta Camera Kabushiki KaishaInventors: Akihito Ikegawa, Masaki Asano, Shuji Iino, Izumi Osawa
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Patent number: 5140373Abstract: A developing apparatus is accommodated in an image forming apparatus to develop an electrostatic laten image formed on an electrostatic latent image support member, using two-component developer of toner and magnetic carrier. The developing apparatus is provided with a developing sleeve opposed to the electrostatic latent image support member, a magnetic roller disposed inside the developing sleeve to hold the carrier on a peripheral surface of the developing sleeve, a toner hopper accommodating the toner and having an opening at its one end, a toner supply roller rotatably disposed in the opening of the toner hopper and opposed to the developing sleeve, a bristle height adjusting member opposed to the developing sleeve on the downstream side of a developing region and on the upstream side of a toner supply region in a direction of movement of the carrier held on the peripheral surface of the developing sleeve.Type: GrantFiled: September 6, 1989Date of Patent: August 18, 1992Assignee: Minolta Camera Kabushiki KaishaInventors: Akihito Ikegawa, Hiroshi Mizuno, Hiroshi Murasaki, Kouichi Etou
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Patent number: 5130755Abstract: A cleaning device which includes a driving roller, a thin film member in an endless belt configuration having a circumferential length slightly longer than that of the driving roller and applied over an outer peripheral face of the driving roller, and elastic members for pressing the thin film member against the driving roller. The thin film member depressed at its opposite ends by the elastic members forms a slackened portion through a space with respect to the surface of the driving roller so that the slackened portion contacts the surface of a photoreceptor drum for cleaning.Type: GrantFiled: December 12, 1990Date of Patent: July 14, 1992Assignee: Minolta Camera Kabushiki KaishaInventors: Akihito Ikegawa, Toshiya Natushara, Hiroshi Mizuno, Yuji Enoguchi
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Patent number: 5128722Abstract: The present invention provides a developing device disposed adjacently to a rotatably arranged electrostatic latent image support member, including;a rotatably arranged toner transport member contacting the electrostatic latent image support member anda member contacting the toner transport member for forming a toner layer on external surface of the toner transport member,the toner transport member including irregularities of 20-200 .mu.m in mean mountain distance on its surface.Type: GrantFiled: January 2, 1991Date of Patent: July 7, 1992Assignee: Minolta Camera Kabushiki KaishaInventors: Toshiya Natsuhara, Hiroshi Mizuno, Yuji Enoguchi, Akihito Ikegawa
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Patent number: 5124757Abstract: In an apparatus and a method for image forming, in which an electrostatic latent image is formed on a surface of a photoreceptor and the latent image is developed and transferred to a transfer member, developer which remains on the surface of the photoreceptor after the transfer is collected to a cleaning device or an electrical charger when an image forming operation is performed, and is returned to a developing device through the photoreceptor when the image forming operation is not performed.Type: GrantFiled: June 24, 1991Date of Patent: June 23, 1992Assignee: Minolta Camera Kabushiki KaishaInventor: Akihito Ikegawa
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Patent number: 5061963Abstract: The present invention discloses a developing device which includes a rotatably arranged photoreceptor, a rotatably disposed elastic roller confronting the photoreceptor, a cylindrically formed flexible member having a peripheral length longer than that of the elastic roller and loosely mounted thereover, and a positioning member to position the flexible member partly into contact with the photoreceptor, the positioning member including an elastic member to form a slack of the flexible member at a location confronting the photoreceptor for the flexible member to contact with the photoreceptor.Type: GrantFiled: February 19, 1991Date of Patent: October 29, 1991Assignee: Minolta Camera Kabushiki KaishaInventors: Akihito Ikegawa, Yuji Enoguchi, Hiroshi Mizuno, Toshiya Natsuhara, Masashi Yamamoto