Patents by Inventor Masashi Fujishima

Masashi Fujishima 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: 7613417
    Abstract: An image forming apparatus uses a two-component developer containing a toner and a carrier. The apparatus has a latent image bearer for bearing an electrostatic latent image. A toner bearer bears the toner to be conveyed to a development region to develop the electrostatic latent image. A developer bearer bears the two-component developer and supplies the toner to the toner bearer. A regulator sets the thickness of a toner layer carried on the toner bearer to 6 ?m to 15 ?m and sets a difference between a half width of a first toner charge number distribution as a number distribution of the charge amount of the toner carried on the toner bearer and that of a second toner charge number distribution as a number distribution of the charge amount of the toner in the two-component developer carried on the developer bearer to 0.8 (10?10 C/m) or smaller.
    Type: Grant
    Filed: June 19, 2008
    Date of Patent: November 3, 2009
    Assignee: Kyocera Mita Corporation
    Inventors: Masashi Fujishima, Shoichi Sakata, Kiyotaka Kobayashi, Yukihiro Mori
  • Publication number: 20090180818
    Abstract: A developing unit includes a developing roller which rotates about a rotational axis to supply toner to a photoreceptor, the developing roller including: a cylindrical core portion which includes an electric conductor; a first resistive layer which covers a cylindrical surface of the core portion; a second resistive layer which covers the first resistive layer, and has electric-resistivity lower than that of the first resistive layer; and a current leakage control member which prevents leakage of electric current from the core portion toward the second resistive layer through an end of the developing roller along a direction of the rotational axis.
    Type: Application
    Filed: January 12, 2009
    Publication date: July 16, 2009
    Inventors: Hiroyuki HAMAKAWA, Akihiro WATANABE, Masashi FUJISHIMA, Hiroshi YAMAZAKI, Asami KOTERA, Sayo UEMURA
  • Publication number: 20090154962
    Abstract: A developing device visualizing an electrostatic latent image previously formed on the surface of an image carrier as toner image, comprising: a developing roller placed at a position facing the image carrier, carrying a toner on the surface thereof, conveying the toner and flying the conveyed toner onto the surface of the image carrier; and a resin layer coated on the surface of the developing roller, wherein the absolute value of the difference in charge between the toners in the upper and lower layers of the toner layer formed on the developing roller as the toner carried on the developing roller is 6 ?C/g or less.
    Type: Application
    Filed: December 10, 2008
    Publication date: June 18, 2009
    Applicant: KYOCERA MITA CORPORATION
    Inventors: Asami Kotera, Hiroyuki Hamakawa, Akihiro Watanabe, Masashi Fujishima, Hiroshi Yamazaki, Sayo Uemura
  • Publication number: 20090003891
    Abstract: An image forming apparatus uses a two-component developer containing a toner and a carrier. The apparatus has a latent image bearer for bearing an electrostatic latent image. A toner bearer bears the toner to be conveyed to a development region to develop the electrostatic latent image. A developer bearer bears the two-component developer and supplies the toner to the toner bearer. A regulator sets the thickness of a toner layer carried on the toner bearer to 6 ?m to 15 ?m and sets a difference between a half width of a first toner charge number distribution as a number distribution of the charge amount of the toner carried on the toner bearer and that of a second toner charge number distribution as a number distribution of the charge amount of the toner in the two-component developer carried on the developer bearer to 0.8 (10?10 C/m) or smaller.
    Type: Application
    Filed: June 19, 2008
    Publication date: January 1, 2009
    Applicant: Kyocera Mita Corporation
    Inventors: Masashi Fujishima, Shoichi Sakata, Kiyotaka Kobayashi, Yukihiro Mori
  • Publication number: 20080317514
    Abstract: The present invention provides an image-forming apparatus comprising a magnetic roll for magnetically holding a two-component developer in which toner and a magnetic carrier are electrostatically bonded, a developing roll in which a thin layer of the toner transferred from the two-component developer on the magnetic roll is formed on the surface, and a latent image support in which a latent image is developed with using the toner on the developing roll by a developing bias applied in relation to the developing roll, wherein the developing roll has a coating layer composed of silicone-modified polyurethane on a surface.
    Type: Application
    Filed: October 16, 2007
    Publication date: December 25, 2008
    Applicant: KYOCERA MITA CORPORATION
    Inventor: Masashi Fujishima
  • Publication number: 20080298847
    Abstract: A developing device uses a two-component developer including at least carriers and toners. The toners are supplied to an image bearing member bearing an electrostatic latent image so that a toner image is developed from the electrostatic latent image. The developing device has a developing roller arranged to oppose the image bearing member; and a magnetic roller arranged to oppose the developing roller. The magnetic roller retains the two-component developer to supply toners to the developing roller. The developing roller and the magnetic roller are rotationally driven in directions to be opposite from one another at an opposed position, and a magnetic pole of the magnetic roller and a magnetic pole of the developing roller have magnetic polarities different from one another at the opposed position. A surface roughness of the magnetic roller is greater than a surface roughness of the developing roller.
    Type: Application
    Filed: May 27, 2008
    Publication date: December 4, 2008
    Applicant: Kyocera Mita Corporation
    Inventors: Toyotsune Inoue, Takahisa Nakaue, Akihiro Watanabe, Masashi Fujishima, Shoichi Sakata, Yukihiro Mori
  • Publication number: 20080292365
    Abstract: An image forming apparatus is characterized in that an absolute value of a difference between a first coefficient of variation in a number distribution of the particle diameter of a toner carried on a developing roller and a second coefficient of variation in a number distribution of the particle diameter of a toner in a two-component developer carried on the magnetic roller is within 5% and an absolute value of a difference between a third coefficient of variation in a number distribution of the particle diameter of a toner of a toner image developed on the outer surface of an image bearing member and the second coefficient of variation is within 6%. With such an image forming apparatus, high-quality images can be stably formed over a long term.
    Type: Application
    Filed: May 20, 2008
    Publication date: November 27, 2008
    Applicant: Kyocera Mita Corporation
    Inventors: Masashi Fujishima, Shoichi Sakata, Takahisa Nakaue, Yukihiro Mori
  • Publication number: 20080232859
    Abstract: An image forming apparatus has a photoconductive member on which a latent image is to be formed, a developing roller for developing the latent image on the photoconductive member by a first bias. A magnetic roller forms a magnetic brush thereon with a two-component developer and forms a thin toner layer on the developing roller by a second bias. The developing roller is aluminum with a surface treated for high resistance. The thickness (T) of the toner layer and the duty ratio (D1) of the first alternating-current bias satisfy relationships of the following equations for calculating the duty ratio (D1) using an application period of a voltage in a direction to transfer the toner from the developing roller towards the photoconductive member as a positive period: 7 ?m?T?13 ?m, and 35%?D1?70%.
    Type: Application
    Filed: March 18, 2008
    Publication date: September 25, 2008
    Applicant: Kyocera Mita Corporation
    Inventors: Shoichi Sakata, Takahisa Nakaue, Toyotsune Inoue, Akihiro Watanabe, Masashi Fujishima, Yukihiro Mori
  • Publication number: 20080232862
    Abstract: An image forming apparatus has a photoconductive member, and a developing roller develops a latent image on the photoconductive member by a first alternating-current bias in the form of a rectangular wave. The following relationships are satisfied in calculating the duty ratio (D1) of the first alternating-current bias using an application period of voltage in a direction to transfer the toner from the developing roller towards the photoconductive member as a positive period: a CV value in the number particle size distribution of the toner is ?25%, 4 ?m?Dt?7 ?m, 105 ?·cm?pv?109 Q?cm, 0.4 ?m?Ra?1.5 ?m, and 35%?D1?75%. where Dt denotes the volume average particle diameter of the toner, pv denotes the intrinsic resistance value of a developing roller surface, Ra denotes the arithmetic average roughness of the developing roller surface.
    Type: Application
    Filed: March 19, 2008
    Publication date: September 25, 2008
    Applicant: Kyocera Mita Corporation
    Inventors: Masashi Fujishima, Shoichi Sakata, Takahisa Nakaue, Toyotsune Inoue, Akihiro Watanabe, Yukihiro Mori
  • Publication number: 20080226320
    Abstract: A developing unit has a voltage-applicator (80) to apply a developing bias voltage to a developing roller (72). The voltage-applicator (80) applies the developing bias voltage for a first duration to apply an AC voltage having a rectangular waveform, and a second duration to stop applying the AC voltage. The AC voltage has a duty ratio of 50% or more in a direction for causing toner to develop an electrostatic latent image. The number of cycles of the AC voltage in the first duration is two or more, and the AC voltage has a voltage in a direction for pulling the toner back to the developing roller, just before transition to the second duration. The developing unit suppresses occurrence of image unevenness due to a fluctuation in developing gap. Thus, an image forming apparatus equipped with the developing unit forms a high-quality image while suppressing image unevenness.
    Type: Application
    Filed: March 5, 2008
    Publication date: September 18, 2008
    Applicant: Kyocera Mita Corporation
    Inventors: Shoichi Sakata, Takahisa Nakaue, Toyotsune Inoue, Akihiro Watanabe, Masashi Fujishima, Yukihiro Mori
  • Publication number: 20080206661
    Abstract: An image forming apparatus having a touchdown-development type developing apparatus, in which a toner collecting roller that collects scattered toner suspended in the vicinity of a toner holding body and a two-component developer holding body is arranged on the downstream side in a rotational direction of the two-component developer holding body from a closest position of the two-component developer holding body and the toner holding body, and between the two-component developer holding body and the housing wall, and further, bias means that applies a bias voltage for collecting the scattered toner to the toner collecting roller, and image density sensing means for sensing a density of a toner image developed on the electrostatic latent image holding body surface or a toner image on a transfer body onto which the toner image developed on the electrostatic latent image holding body surface is transferred to control the bias voltage are provided.
    Type: Application
    Filed: February 12, 2008
    Publication date: August 28, 2008
    Inventors: Masashi Fujishima, Akihiro Watanabe, Sayo Uemura, Yukihiro Mori
  • Publication number: 20080181675
    Abstract: An image forming apparatus includes a latent image carrying member, a two-component developer carrying member holding on an outer surface a developer containing carrier beads and toner particles, the two-component developer carrying member having a first magnetic element mounted therein, a toner carrying member carrying a thin toner layer on an outer surface, a toner collecting roller for collecting the toner particles scattered and suspended in the vicinity of the two-component developer carrying member and the toner carrying member, the toner collecting roller having a second magnetic element mounted therein, and a housing accommodating the two-component developer carrying member, the toner carrying member and the toner collecting roller. The toner collecting roller is located face to face with the two-component developer carrying member with the first and second magnetic elements disposed to face each other with oppositely directed polarities.
    Type: Application
    Filed: January 25, 2008
    Publication date: July 31, 2008
    Applicant: Kyocera Mita Corporation
    Inventors: Masashi Fujishima, Kiyotaka Kobayashi, Yuki Matsui, Yukihiro Mori, Sayo Uemura, Akihiro Watanabe
  • Publication number: 20070086801
    Abstract: In an image forming apparatus, a control section 41 adjusts the surface potential of a photoconductor or the developing potential of a developer carrying member based on the detection result of a surface potential sensor 44, and performs first correction whereby, relative to the reference value of the applied bias of a charger 2 or the developing bias of the developer carrying member in a developing unit 4 as observed during potential adjustment, the applied bias or the developing bias is varied so as to keep constant the potential difference between the surface potential of the photoconductor and the developing potential of the developer carrying member during image formation. The control section also performs second correction whereby the applied bias or the developing bias is restored to the reference value over a predetermined period after the completion of continuous image formation.
    Type: Application
    Filed: October 13, 2006
    Publication date: April 19, 2007
    Inventors: Shingo Sakato, Ai Takagami, Eiji Nimura, Hiroyuki Hamakawa, Yoshinori Horiuchi, Masashi Fujishima
  • Patent number: 7043181
    Abstract: The electrophotographic image formation apparatus of the present invention adopts a developer roller, which is made of aluminum and has an aluminum oxide film of at least 5 ?m in thickness formed on surface thereof. In the image formation apparatus, a gap between the developer roller and a photoreceptor drum 3 is set in a range of 150 to 300 ?m. The image formation method of the present invention regulates a frequency of AC voltage in a non-development state to be higher than that in a development state, when an AC voltage is applied onto the developer roller to cause flight of toner from the developer roller to the photoreceptor, and selectively makes charged toner fly onto the electrostatic latent image for development. The present invention provides the effective development technique to prevent leakage of the applied voltage between the developer roller and the photoreceptor drum.
    Type: Grant
    Filed: April 1, 2004
    Date of Patent: May 9, 2006
    Assignee: Kyocera Mita Corporation
    Inventors: Masashi Fujishima, Shoichi Sakata
  • Patent number: 6879794
    Abstract: Disclosed are image forming apparatus [1] which comprises removing a toner remained on the surface of the rotatable image carrier by cleaning means after going through developing means and transferring means; said cleaning means has an elastic blade and is contacted with the surface of the image carrier at a contact pressure within 8 to 20 g/cm, and a press-contact angle of the elastic blade of 12 to 30°; and said image carrier is an organic photosensitive material having a photosensitive layer made of a binder resin containing an electric charge generating material and an electric charge transferring material; and image forming apparatus [2], comprising a single-layer type photosensitive layer made of a binder resin containing an electric charge generating material, an electron transferring material and a hole transferring material, and the solid content of the binder resin is within 50 to 70 wt % of the whole solid content in the photosensitive layer and, a pair of paper transporting rollers are arranged on
    Type: Grant
    Filed: February 14, 2002
    Date of Patent: April 12, 2005
    Assignee: Kyocera Mita Corporation
    Inventors: Jun Azuma, Ayako Yashima, Yukimasa Watanabe, Keisuke Oba, Masashi Fujishima, Takashi Nagashima
  • Publication number: 20040228661
    Abstract: The electrophotographic image formation apparatus of the present invention adopts a developer roller, which is made of aluminum and has an aluminum oxide film of at least 5 &mgr;m in thickness formed on surface thereof. In the image formation apparatus, a gap between the developer roller and a photoreceptor drum 3 is set in a range of 150 to 300 &mgr;m. The image formation method of the present invention regulates a frequency of AC voltage in a non-development state to be higher than that in a development state, when an AC voltage is applied onto the developer roller to cause flight of toner from the developer roller to the photoreceptor, and selectively makes charged toner fly onto the electrostatic latent image for development. The present invention provides the effective development technique to prevent leakage of the applied voltage between the developer roller and the photoreceptor drum.
    Type: Application
    Filed: April 1, 2004
    Publication date: November 18, 2004
    Inventors: Masashi Fujishima, Shoichi Sakata
  • Publication number: 20020159804
    Abstract: Disclosed are image forming apparatus [1] which comprises removing a toner remained on the surface of the rotatable image carrier by cleaning means after going through developing means and transferring means; said cleaning means has an elastic blade and is contacted with the surface of the image carrier at a contact pressure within 8 to 20 g/cm, and a press-contact angle of the elastic blade of 12 to 30°; and said image carrier is an organic photosensitive material having a photosensitive layer made of a binder resin containing an electric charge generating material and an electric charge transferring material; and image forming apparatus [2], comprising a single-layer type photosensitive layer made of a binder resin containing an electric charge generating material, an electron transferring material and a hole transferring material, and the solid content of the binder resin is within 50 to 70 wt % of the whole solid content in the photosensitive layer and, a pair of paper transporting
    Type: Application
    Filed: February 14, 2002
    Publication date: October 31, 2002
    Inventors: Jun Azuma, Ayako Yashima, Yukimasa Watanabe, Keisuke Oba, Masashi Fujishima, Takashi Nagashima
  • Patent number: 6266499
    Abstract: In a transfer method of this invention, a paper powder-removing device having a pair of an insulating roller and an electrically conducting roller is provided on a transfer paper conveyer passage, and a transfer paper is passed through between a pair of the above rollers prior to being fed to a transfer zone (between a transfer roller and a photosensitive material drum). The transfer paper is passed through the pair of rollers in a state where the electrically conducting roller is maintained at a potential of a polarity same as, or opposite to, that of the transfer roller depending upon the position of the electrically conducting roller (position on a side of the transfer surface of the transfer paper or position on a side opposite to the transfer surface) in the paper powder-removing device, in order to reliably remove the paper powder from the transfer paper and to effectively prevent the adhesion of the paper powder on the surface of the photosensitive material drum.
    Type: Grant
    Filed: May 22, 2000
    Date of Patent: July 24, 2001
    Assignee: Kyocera Mita Corporation
    Inventors: Takahiko Murata, Masashi Fujishima, Masanobu Maeshima