Patents by Inventor Takaaki Ikegami

Takaaki Ikegami 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: 6861188
    Abstract: Electrophotographic photoreceptor having a photosensitive layer containing an amino compound selected from formulae 1 to 22 in the specification.
    Type: Grant
    Filed: September 6, 2002
    Date of Patent: March 1, 2005
    Assignee: Ricoh Company Limited
    Inventors: Takaaki Ikegami, Yasuo Suzuki, Tomoyuki Shimada, Nozomu Tamoto, Hidetoshi Kami
  • Patent number: 6853823
    Abstract: An electrophotographic photoreceptor includes an electroconductive substrate. A charge generation layer overlies the electroconductive substrate. A first charge transport layer overlying the charge generation layer includes a first charge transport material (D1) and a first binder resin (R1). A second charge transport layer overlying the first charge transport layer includes a filler, a second charge transport material (D2) and a second binder resin (R2). The first and second charge transport layers have a total thickness of from 5 to 25 ?m. A weight ratio (D1/R1) of the first charge transport material (D1) to the first binder resin (R1) in the first charge transport layer is greater than a weight ratio (D2/R2) of the second charge transport material (D2) to the second binder resin (R2) in the second charge transport layer.
    Type: Grant
    Filed: March 11, 2003
    Date of Patent: February 8, 2005
    Assignee: Ricoh Company Ltd.
    Inventors: Akihiro Sugino, Ryohichi Kitajima, Yoshiaki Kawasaki, Takaaki Ikegami, Eiji Kurimoto
  • Patent number: 6853834
    Abstract: An image forming apparatus including a photoreceptor having an electroconductive substrate, a photosensitive layer overlying the electroconductive substrate, and a protection layer including an inorganic filler in an amount of from 3 to 25% by weight based on total weight of the protection layer and a binder resin, and overlying the photosensitive layer. The apparatus further including a charger, an irradiator, an image developer, and a transferer transferring a toner image onto a transfer material. The apparatus also includes a cleaner cleaning the photoreceptor, including a rotatable core and a looped brush fiber provided on the surface of the rotatable core so as to contact the photoreceptor. A top of the looped brush fiber is positioned on an upstream side from a root of the looped brush fiber relative to a rotating direction of the rotatable core.
    Type: Grant
    Filed: July 29, 2003
    Date of Patent: February 8, 2005
    Assignee: Ricoh Company Limited
    Inventors: Eiji Kurimoto, Ryohichi Kitajima, Yoshiaki Kawasaki, Akihiro Sugino, Takaaki Ikegami
  • Publication number: 20050026058
    Abstract: An electrophotographic photoreceptor including an electroconductive substrate; a photosensitive layer overlying the electroconductive substrate optionally via an undercoat layer; and optionally a protective layer overlying the photosensitive layer, wherein an outermost layer of the electrophotographic photoreceptor comprises a binder resin; a particulate fluorine-containing resin in an amount of from 20 to 70% by volume based on total volume of the outermost layer, wherein a surface free energy of the particulate fluorine-containing resin is larger than a surface free energy of the binder resin; and a fluorochemical surfactant in an amount of from 5 to 70% by weight based on total weight of the binder resin.
    Type: Application
    Filed: July 28, 2004
    Publication date: February 3, 2005
    Inventors: Hidetoshi Kami, Shinji Nousho, Takaaki Ikegami, Eiji Kurimoto, Hideo Nakamori, Akihiro Sugino, Yasuyuki Yamashita
  • Publication number: 20050008957
    Abstract: A photoreceptor including an electroconductive substrate; a photosensitive layer; and optionally a protective layer, wherein an outermost layer thereof includes a filler, an organic compound having an acid value of from 10 to 700 mg KOH/g and at least one compound selected from the group consisting of compounds having the following formulae (1) and (2): wherein R1 (R3) and R2 (R4) independently represent a substituted or an unsubstituted aromatic hydrocarbon group, or a substituted or an unsubstituted alkyl group, and optionally share bond connectivity to form a heterocyclic group including a nitrogen atom; Ar1 (Ar3) and Ar2 (Ar4) independently represent a substituted or a unsubstituted aromatic ring group; k (K) and m (M) independently represent 0 or an integer of from 1 to 3, wherein k (K) and m (M) are not 0 at the same time; and n (n?) represents an integer of from 1 to 3.
    Type: Application
    Filed: June 1, 2004
    Publication date: January 13, 2005
    Inventors: Takaaki Ikegami, Tomoyuki Shimada, Yasuo Suzuki, Nozomu Tamoto, Hidetoshi Kami, Yuuji Takana
  • Patent number: 6824939
    Abstract: An image forming apparatus including a photoreceptor which includes an electroconductive substrate, a photosensitive layer including a charge generation material and a charge transport material and located overlying the electroconductive substrate, and a protective layer including an inorganic filler having an average particle diameter (d) and a binder resin; and an imagewise light irradiator configured to irradiate the photoreceptor with a laser light beam having a wavelength of (&lgr;) to form a light spot having a diameter (L) in the minor axis direction thereof on a surface of the photoreceptor, wherein the relationship 0.1<3.75×10−3L/&lgr;<d/&lgr;<0.5 is satisfied. An image forming method is also provided which includes irradiating a surface of the photoreceptor with a laser beam such that the above-mentioned relationship is satisfied.
    Type: Grant
    Filed: December 11, 2002
    Date of Patent: November 30, 2004
    Assignee: Ricoh Company Limited
    Inventors: Eiji Kurimoto, Ryohichi Kitajima, Takaaki Ikegami, Yoshiaki Kawasaki
  • Publication number: 20040180280
    Abstract: A photoreceptor including a photosensitive layer including a specific diamine compound, or a photoreceptor including an electroconductive substrate; a photosensitive layer located overlying the electroconductive substrate; and optionally a protective layer located overlying the photosensitive layer, wherein an outermost layer of the photoreceptor includes a filler, an organic compound having an acid value of from 10 to 700 mgKOH/g and a specific diamine compound. An image forming method, an image forming apparatus and a process cartridge using the photoreceptor are also provided. A method for manufacturing the photoreceptor including the steps of preparing a coating liquid including the filler, the organic compound, the specific diamine compound and an antioxidant; and coating the coating liquid is also provided.
    Type: Application
    Filed: March 4, 2004
    Publication date: September 16, 2004
    Inventors: Takaaki Ikegami, Tomoyuki Shimada, Yasuo Suzuki
  • Publication number: 20040170911
    Abstract: An electrophotographic photoreceptor including an electroconductive substrate and a photosensitive layer on the electroconductive substrate, wherein the photosensitive layer includes at least a compound having a substituted or unsubstituted alkylamino group and a charge transport material, and wherein an oxidation potential (Eox1) of the substituted or unsubstituted alkylamino group and an oxidation potential (Eox2) of the charge transport material satisfy the following relationship (I):
    Type: Application
    Filed: February 24, 2004
    Publication date: September 2, 2004
    Inventors: Tomoyuki Shimada, Takaaki Ikegami, Yasuo Suzuki
  • Patent number: 6777149
    Abstract: An image forming apparatus including at least an image irradiator configured to irradiate a photoreceptor with a coherent light beam while scanning to form pixel light spots thereon for forming an electrostatic latent image thereon, wherein the light spots overlap with adjacent light spots; and an image developer configured to develop the electrostatic latent image with a developer, wherein the photoreceptor comprises an intermediate layer located overlying an electroconductive substrate, a charge generation layer located overlying the intermediate layer and a charge transport layer located overlying the charge generation layer, wherein the charge generation layer satisfies the following relationship: T1≦3.5% wherein T1 represents a relative mirror reflectance of the charge generation layer against the coherent light beam when the coherent light beam irradiates the charge generation layer at an incident angle of 5°.
    Type: Grant
    Filed: March 25, 2002
    Date of Patent: August 17, 2004
    Assignee: Ricoh Company Limited
    Inventors: Takaaki Ikegami, Akihiro Sugino
  • Publication number: 20040126687
    Abstract: An electrophotographic photoconductor having at least a photosensitive layer on a conductive support, wherein the electrophotographic photoconductor comprising, in the outermost layer thereof: a filler, an organic compound having an acid value of 10-400 mgKOH/g, and at least one of compounds represented by the following general formulas 1 and 2: 1
    Type: Application
    Filed: September 23, 2003
    Publication date: July 1, 2004
    Inventors: Takaaki Ikegami, Tomoyuki Shimada, Yasuo Suzuki, Nozomu Tamoto, Hidetoshi Kami
  • Publication number: 20040028435
    Abstract: An image forming apparatus including a photoreceptor having an electroconductive substrate, a photosensitive layer overlying the electroconductive substrate, and a protection layer including an inorganic filler in an amount of from 3 to 25% by weight based on total weight of the protection layer and a binder resin, and overlying the photosensitive layer. The apparatus further including a charger, an irradiator, an image developer, and a transferer transferring a toner image onto a transfer material. The apparatus also includes a cleaner cleaning the photoreceptor, including a rotatable core and a looped brush fiber provided on the surface of the rotatable core so as to contact the photoreceptor. A top of the looped brush fiber is positioned on an upstream side from a root of the looped brush fiber relative to a rotating direction of the rotatable core.
    Type: Application
    Filed: July 29, 2003
    Publication date: February 12, 2004
    Inventors: Eiji Kurimoto, Ryohichi Kitajima, Yoshiaki Kawasaki, Akihiro Sugino, Takaaki Ikegami
  • Publication number: 20030215726
    Abstract: An electrophotographic photoreceptor includes an electroconductive substrate. A charge generation layer overlies the electroconductive substrate. A first charge transport layer overlying the charge generation layer includes a first charge transport material (D1) and a first binder resin (R1). A second charge transport layer overlying the first charge transport layer includes a filler, a second charge transport material (D2) and a second binder resin (R2). The first and second charge transport layers have a total thickness of from 5 to 25 &mgr;m. A weight ratio (D1/R1) of the first charge transport material (D1) to the first binder resin (R1) in the first charge transport layer is greater than a weight ratio (D2/R2) of the second charge transport material (D2) to the second binder resin (R2) in the second charge transport layer.
    Type: Application
    Filed: March 11, 2003
    Publication date: November 20, 2003
    Inventors: Akihiro Sugino, Ryohichi Kitajima, Yoshiaki Kawasaki, Takaaki Ikegami, Eiji Kurimoto
  • Publication number: 20030206226
    Abstract: An image forming apparatus including a photoreceptor which includes an electroconductive substrate, a photosensitive layer including a charge generation material and a charge transport material and located overlying the electroconductive substrate, and a protective layer including an inorganic filler having an average particle diameter (d) and a binder resin; and an imagewise light irradiator configured to irradiate the photoreceptor with a laser light beam having a wavelength of (&lgr;) to form a light spot having a diameter (L) in the minor axis direction thereof on a surface of the photoreceptor, wherein the relationship 0.1<3.75×10−3L/&lgr;<d/&lgr;<0.5 is satisfied. An image forming method is also provided which includes irradiating a surface of the photoreceptor with a laser beam such that the above-mentioned relationship is satisfied.
    Type: Application
    Filed: December 11, 2002
    Publication date: November 6, 2003
    Applicant: RICOH COMPANY LIMITED
    Inventors: Eiji Kurimoto, Ryohichi Kitajima, Takaaki Ikegami, Yoshiaki Kawasaki
  • Publication number: 20030194627
    Abstract: Electrophotographic photoreceptor having a photosensitive layer containing an amino compound selected from formulae 1 to 22 in the specification.
    Type: Application
    Filed: September 6, 2002
    Publication date: October 16, 2003
    Inventors: Takaaki Ikegami, Yasuo Suzuki, Tomoyuki Shimada, Nozomu Tamoto, Hidetoshi Kami
  • Publication number: 20030059693
    Abstract: An image forming apparatus including at least an image irradiator configured to irradiate a photoreceptor with a coherent light beam while scanning to form pixel light spots thereon for forming an electrostatic latent image thereon, wherein the light spots overlap with adjacent light spots; and an image developer configured to develop the electrostatic latent image with a developer, wherein the photoreceptor comprises an intermediate layer located overlying an electroconductive substrate, a charge generation layer located overlying the intermediate layer and a charge transport layer located overlying the charge generation layer, wherein the charge generation layer satisfies the following relationship:
    Type: Application
    Filed: March 25, 2002
    Publication date: March 27, 2003
    Inventors: Takaaki Ikegami, Akihiro Sugino
  • Patent number: 6030736
    Abstract: An electrophotographic photoconductor is provided which includes a photoconductive layer formed overlying an electroconductive substrate, wherein the photoconductor includes in a top layer thereof a polysiloxane mixture selected from the group consisting of a polysiloxane mixture of an unmodified polysiloxane compound and a modified polysiloxane compound, a mixture of a methacryl modified polysiloxane compound and an alkyl modified polysiloxane compound, a mixture of a methacryl modified polysiloxane compound and a vinyl modified polysiloxane compound, and a mixture of an alkyl modified polysiloxane compound and a vinyl modified polysiloxane compound. The photoconductor has good durability.
    Type: Grant
    Filed: March 30, 1998
    Date of Patent: February 29, 2000
    Assignee: Ricoh Company, Ltd.
    Inventors: Takaaki Ikegami, Yasuo Suzuki, Hiroshi Nakai, Nozomu Tamoto, Koji Kishida
  • Patent number: 5702855
    Abstract: An electrophotographic photoconductor has an electroconductive support, and a single-layered photoconductive layer formed thereon containing a charge generation material, a charge transport material, a binder resin and a mixture of a phenol compound and an organic sulfur-containing compound.
    Type: Grant
    Filed: August 7, 1996
    Date of Patent: December 30, 1997
    Assignee: Ricoh Company, Ltd.
    Inventors: Takaaki Ikegami, Takashi Rokutanzono, Eiji Kurimoto
  • Patent number: 5578405
    Abstract: An electrophotographic photoconductor includes an electroconductive support and a single-layered photoconductive layer formed thereon, containing a charge transporting material, a binder resin, and a simultaneously pulverized mixture including at least one disazo pigment of formula (1) and at least one trisazo pigment of formula (2), which is obtained by simultaneously pulverizing those azo pigments: ##STR1## wherein R.sup.1 and R.sup.2 each is hydrogen, a halogen atom, trifluoromethyl group, nitro group or cyano group; R.sup.3 is hydrogen, chlorine, fluorine, iodine, bromine, nitro group or cyano group; and Ar.sup.1, Ar.sup.2 and Ar.sup.3 each is a coupler radical, which may be the same or different.
    Type: Grant
    Filed: October 14, 1994
    Date of Patent: November 26, 1996
    Assignee: Ricoh Company
    Inventors: Takaaki Ikegami, Eiji Kurimoto, Takashi Rokutanzono, Katsuichi Ohta, Masaomi Sasaki, Yasuo Suzuki, Kaoru Tadokoro, Megumi Kawahara, Masayuki Koyano