Patents by Inventor Tahei Ishiwatari
Tahei Ishiwatari 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: 6233424Abstract: An image forming apparatus for forming an image in a receiving sheet by embedding toner in an image receiving layer formed on a base of the receiving sheet. The image forming apparatus uses a toner having an external additive, and the critical surface tension of the image receiving layer is made to be smaller than the critical surface tension of external additive. Further, the image receiving layer has a viscoelastic characteristic such that its storage modulus (G′) is between 1×102 Pa to 1×105 Pa and its loss modulus (G″) is between 1×102 Pa to 1×105 Pa at temperatures at which the toner is fixed. Furthermore, the image receiving layer contains an aromatic ester compound, more preferably the aromatic polyester compound being dialkyl phtalate. Still further, the image receiving layer has a Rockwell hardness (R scale) HRa of 121 or lower.Type: GrantFiled: January 15, 1999Date of Patent: May 15, 2001Assignee: Seiko Epson CorporationInventors: Shuhei Mohri, Tahei Ishiwatari, Masanao Kunugi
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Patent number: 6226484Abstract: A developing unit of the present invention includes a case which accommodates toner containing pigment, a developing roller, a supply roller formed of an elastic member arranged to be pressed against a surface of the developing roller in such a manner as to supply toner to the surface of the developing roller. The toner contains a first and second additive having a specific covering ratio to the surface matrices in the toner.Type: GrantFiled: August 9, 1999Date of Patent: May 1, 2001Assignee: Seiko Epson CorporationInventors: Kazuhiro Ichikawa, Yoshihiro Nakashima, Hidenori Kin, Tomoe Aruga, Yoichi Yamada, Yukio Takayama, Tahei Ishiwatari
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Patent number: 6223015Abstract: A recording medium carrier system of an image forming apparatus is constituted by independent units as a paper supply cassette, a paper feed unit, a transfer unit, a fixing unit, and a paper ejecting unit. An intermediate transfer unit in the transfer unit is provided with an intermediate transfer belt to which a toner image formed on a photoconductive drum is primarily transferred at a primary transfer position and which secondarily transfers the toner image on a recording medium at a secondary transfer position, and a driving roller for circulating the intermediate transfer belt. The primary transfer position is arranged close to the driving roller.Type: GrantFiled: November 25, 1998Date of Patent: April 24, 2001Assignee: Seiko Epson CorporationInventors: Toshiya Takahata, Akira Kubota, Tatsuro Osawa, Nobumasa Abe, Takehiko Okamura, Hiroshi Ito, Tahei Ishiwatari, Toshihiko Yamazaki
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Patent number: 6198893Abstract: A plurality of developing units each includes a case which accommodates toner containing pigment, a developing roller, a supply roller formed of an elastic member arranged to be pressed against a surface of the developing roller in such a manner as to supply toner to the surface of the developing roller and a conveying fin. The developing roller, supply roller, and conveying fin for each developing unit are angularly arranged in a particular manner.Type: GrantFiled: August 9, 1999Date of Patent: March 6, 2001Assignee: Seiko Epson CorporationInventors: Kazuhiro Ichikawa, Yoshihiro Nakashima, Hidenori Kin, Tomoe Aruga, Yoichi Yamada, Yukio Takayama, Tahei Ishiwatari
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Patent number: 6192209Abstract: A developing unit of the present invention includes a case which accommodates toner containing pigment, a developing roller, a supply roller having chamfered ends and formed of an elastic member arranged to be pressed against a surface of the developing roller in such a manner as to supply toner to the surface of the developing roller. Also a first sealing member is disposed on the side ends faces of the developing roller and supply roller so as to prevent leakage to the outside portion of the case. Further, a second sealing member in the form of a film is pressed against a lower surface of the developing roller in order to prevent leakage of toner, wherein a quantity &dgr; of displacement of the sealing member due to its abutment against the developing roller satisfies 0.1 mm<&dgr;<0.8 mm, and the thickness t of the second sealing member satisfies 50 &mgr;m<t<500 &mgr;m.Type: GrantFiled: August 9, 1999Date of Patent: February 20, 2001Assignee: Seiko Epson CorporationInventors: Kazuhiro Ichikawa, Yoshihiro Nakashima, Hidenori Kin, Tomoe Aruga, Yoichi Yamada, Yukio Takayama, Tahei Ishiwatari
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Patent number: 6185380Abstract: An image forming apparatus which is able to form either single or double sided copies on a recording medium while achieving an excellent image quality in either a matted or glossy finish. The image forming apparatus includes a fixing portion in which a first roller includes a first temperature and hardness for forming a matted image, whereas a second roller includes a higher temperature and hardness for forming a glossy image. Alternatively, or in addition, to different hardness and temperatures, the recording medium can be conveyed at a first speed to form a matted image, and a slower speed to form a glossy image. The image forming apparatus further includes an inverse and re-fixing sub-mode, which utilizes an inverting and returning passage, for reducing the curl in a recording medium, and thus also reducing the instances in which clogging takes place. The inverting and returning passage has a length sufficient to accommodate a plurality of recording mediums.Type: GrantFiled: April 28, 2000Date of Patent: February 6, 2001Assignee: Seiko Epson CorporationInventors: Nobumasa Abe, Kaneo Yoda, Takayuki Shiraki, Tahei Ishiwatari, Kazutoshi Fujisawa, Naoyuki Okumura, Kenjiro Yoshioka, Hiroshi Tanaka
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Patent number: 6173139Abstract: A recording medium carrier system of an image forming apparatus is constituted by independent units as a paper supply cassette, a paper feed unit, a transfer unit, a fixing unit, and a paper ejecting unit. An intermediate transfer unit in the transfer unit is provided with an intermediate transfer belt to which a toner image formed on a photoconductive drum is primarily transferred at a primary transfer position and which secondarily transfers the toner image on a recording medium at a secondary transfer position, and a driving roller for circulating the intermediate transfer belt. The primary transfer position is arranged close to the driving roller.Type: GrantFiled: January 30, 1998Date of Patent: January 9, 2001Assignee: Seiko Epson CorporationInventors: Toshiya Takahata, Akira Kubota, Tatsuro Osawa, Nobumasa Abe, Takehiko Okamura, Hiroshi Ito, Tahei Ishiwatari, Toshihiko Yamazaki
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Patent number: 6163674Abstract: A developing unit of the present invention includes a case which accommodates toner containing pigment, a developing roller, and a supply roller formed of an elastic material arranged to be pressed against a surface of the developing roller in such a manner as to supply toner to the surface of the developing roller. A sealing member is disposed on the side ends of the developing roller and supply roller so as to prevent leakage to the outside portion of the case. A blade at least longer than the developing roller restrains the quantity of toner on the developing roller. The blade has a radius of curvature between 30 .mu.m and 150 .mu.m.Type: GrantFiled: August 9, 1999Date of Patent: December 19, 2000Assignee: Seiko Epson CorporationInventors: Kazuhiro Ichikawa, Yoshihiro Nakashima, Hidenori Kin, Tomoe Aruga, Yoichi Yamada, Yukio Takayama, Tahei Ishiwatari
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Patent number: 6151474Abstract: A developing unit of the present invention includes a case which accommodates toner containing pigment, a developing roller, a supply roller formed of an elastic member arranged to be pressed against a surface of the developing roller in such a manner as to supply toner to the surface of the developing roller. Moreover, the percentage of open cells in the elastic supply roller is made to be 30% or higher and depth of engagement of the supply roller to the developing roller is made to 0.4 mm or smaller. The toner has shape factors SF-1 of 150 or smaller and SF-2 of 140 or smaller.Type: GrantFiled: August 9, 1999Date of Patent: November 21, 2000Assignee: Seiko Epson CorporationInventors: Kazuhiro Ichikawa, Yoshihiro Nakashima, Hidenori Kin, Tomoe Aruga, Yoichi Yamada, Yukio Takayama, Tahei Ishiwatari
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Patent number: 6094554Abstract: A developing unit of the present invention includes a case which accommodates toner containing pigment, a developing roller, a supply roller having chamfered ends and formed of an elastic member arranged to be pressed against a surface of the developing roller in such a manner as to supply toner to the surface of the developing roller. The side surfaces of the developing roller have a surface roughness of 0.5 .mu.m or smaller in Rmax.Type: GrantFiled: August 9, 1999Date of Patent: July 25, 2000Assignee: Seiko Epson CorporationInventors: Kazuhiro Ichikawa, Yoshihiro Nakashima, Hidenori Kin, Tomoe Aruga, Yoichi Yamada, Yukio Takayama, Tahei Ishiwatari
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Patent number: 6078760Abstract: An image forming apparatus which is able to form either single or double sided copies on a recording medium while achieving an excellent image quality in either a matted or glossy finish. The image forming apparatus includes a fixing portion in which a first roller includes a first temperature and hardness for forming a matted image, whereas a second roller includes a higher temperature and hardness for forming a glossy image. Alternatively, or in addition, to different hardness and temperatures, the recording medium can be conveyed at a first speed to form a matted image, and a slower speed to form a glossy image. The image forming apparatus further includes an inverse and re-fixing sub-mode, which utilizes an inverting and returning passage, for reducing the curl in a recording medium, and thus also reducing the instances in which clogging takes place. The inverting and returning passage has a length sufficient to accommodate a plurality of recording mediums.Type: GrantFiled: July 13, 1998Date of Patent: June 20, 2000Assignee: Seiko Epson CorporationInventors: Nobumasa Abe, Kaneo Yoda, Takayuki Shiraki, Tahei Ishiwatari, Kazutoshi Fujisawa, Naoyuki Okumura, Kenjiro Yoshioka, Hiroshi Tanaka
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Patent number: 5950052Abstract: The present invention provides an electrophotographic image forming apparatus capable of forming a high quality image by eliminating an expansion/contraction, displacement in color or nonuniformity of color of the image formed on a transfer member. An image carrier gear for driving an image carrier is driven by a driving means gear at an image carrier driving position and transmits driving force to conveying force transmitting gear at a transfer driving position. The conveying force transmitting gear transmits conveying force to the transfer member. A time during which the image carrier moves from a latent image forming position to a transferring position is made substantially equal to a time during which the image carrier gear moves from an image carrier driving position to a transfer driving position.Type: GrantFiled: September 12, 1997Date of Patent: September 7, 1999Assignee: Seiko Epson CorporationInventors: Yujiro Nomura, Akira Kubota, Tahei Ishiwatari, Kuniaki Tanaka, Tomoe Aruga
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Patent number: 5701554Abstract: A fixing apparatus including a heating member and a pressurizing member that are in contact with each other under pressure to define a nip through which a sheet carrying an unfixed toner image is passed and a temperature sensor for sensing the temperature of the heating member. The fixing apparatus further includes a temperature controller for proportionally controlling an electric power supplied to the heating member, based on the sensed temperature supplied from the temperature sensor, and for controlling the temperature of the heating member so that it is at a predetermined target temperature, and a heating condition changing device for changing a heating condition based on the target temperature and the sensed temperature when the temperature of the heating member is sensed.Type: GrantFiled: June 12, 1995Date of Patent: December 23, 1997Assignee: Seiko Epson CorporationInventors: Hiroshi Tanaka, Toru Fujita, Tahei Ishiwatari
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Patent number: 4948692Abstract: A combination toner for xerographic image formation having conductive portions and insulating portions is provided. The conductive portions function to accumulate a charge in the toner particles and the insulating portions function to lengthen the period of discharge of the accumulated charge. The toner can be either magnetic or non-magnetic and improves image formation and transfer.Type: GrantFiled: May 3, 1988Date of Patent: August 14, 1990Assignee: Seiko Epson CorporationInventors: Koichi Higashimura, Yoshinori Miyazawa, Tsuneo Handa, Teruyuki Mizumoto, Hiroshi Ito, Atsushi Uchino, Masanobu Motoki, Masanao Kunugi, Tahei Ishiwatari, Hidetsugu Shimura