Patents by Inventor Takaaki Kohtaki
Takaaki Kohtaki 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).
-
Publication number: 20140029972Abstract: Provided is an electrophotographic magnetic sealing member for sealing magnetic toner contains a magnetic material and a binder resin. The magnetic material at least includes Nd and Fe, and further includes at least one element selected from the group consisting of Sr and Ba, at least one element selected from the group consisting of Pr and La, at least one element selected from the group consisting of B, Si, In, and P, and an Al element. The magnetic material has a residual magnetic flux density of 270 mT to 500 mT, an intrinsic coercive force of 400 kA/m to 850 kA/m, and a maximum energy product of 10.0 kJ/m3 to 40.0 kJ/m3. The electrophotographic magnetic sealing member contains 3.0 parts by mass to 15.0 parts by mass of the binder resin based on 100.0 parts by mass of the magnetic material.Type: ApplicationFiled: July 30, 2013Publication date: January 30, 2014Applicant: CANON KASEI KABUSHIKI KAISHAInventors: Keisuke Sakai, Takaaki Kohtaki, Junichi Ootake
-
Patent number: 7300733Abstract: To provide a black toner having excellent charging property and transferring property against a severe environmental change. The black toner includes toner particle containing at least a binder resin, carbon black and a releasing agent, wherein: the toner particles have a weight-average particle diameter of 3.5 to 8.0 ?m; total amount of acid value and hydroxyl value of the toner is 30 to 75 mgKOH/g; average circularity of particles contained in the toner having circle-equivalent diameter of 2 ?m or more is 0.915 to 0.960; loss tangent tan? (103 to 104 Hz) of the toner is represented by the following expression: tan? (103 to 104 Hz)?0.0060 where the loss tangent tan? is represented by ??/?? where ?? denotes dielectric loss factor and ?? denotes dielectric constant, and tan? (103 to 104 Hz) denotes the loss tangent in a frequency range of 103 to 104 Hz; and a ratio of tan? (105 Hz) to tan? (5×104 Hz) is represented by the following expression: 1.05?tan? (105 Hz)/tan? (5×104 Hz)?1.Type: GrantFiled: September 14, 2005Date of Patent: November 27, 2007Assignee: Canon Kabushiki KaishaInventors: Nobuyoshi Sugahara, Takaaki Kohtaki, Yasuhiro Ichikawa, Tetsuya Ida, Kazuhiko Hayami, Nozomu Komatsu
-
Patent number: 7022449Abstract: To provide a black toner having excellent charging property and transferring property against a severe environmental change. The black toner includes toner particle containing at least a binder resin, carbon black and a releasing agent, wherein: the toner particles have a weight-average particle diameter of 3.5 to 8.0 ?m; total amount of acid value and hydroxyl value of the toner is 30 to 75 mgKOH/g; average circularity of particles contained in the toner having circle-equivalent diameter of 2 ?m or more is 0.915 to 0.960; loss tangent tan ? (103 to 104 Hz) of the toner is represented by the following expression: tan ?(103 to 104 Hz)?0.0060 where the loss tangent tan ? is represented by ??/?? where ?? denotes dielectric loss factor and ?? denotes dielectric constant, and tan ? (103 to 104 Hz) denotes the loss tangent in a frequency range of 103 to 104 Hz; and a ratio of tan ? (105 Hz) to tan ? (5×104 Hz) is represented by the following expression: 1.05?tan ?(105 Hz)/tan ?(5×104 Hz)?1.Type: GrantFiled: July 30, 2003Date of Patent: April 4, 2006Assignee: Canon Kabushiki KaishaInventors: Nobuyoshi Sugahara, Takaaki Kohtaki, Yasuhiro Ichikawa, Tetsuya Ida, Kazuhiko Hayami, Nozomu Komatsu
-
Publication number: 20060014095Abstract: To provide a black toner having excellent charging property and transferring property against a severe environmental change. The black toner includes toner particle containing at least a binder resin, carbon black and a releasing agent, wherein: the toner particles have a weight-average particle diameter of 3.5 to 8.0 ?m; total amount of acid value and hydroxyl value of the toner is 30 to 75 mgKOH/g; average circularity of particles contained in the toner having circle-equivalent diameter of 2 ?m or more is 0.915 to 0.960; loss tangent tan ? (103 to 104 Hz) of the toner is represented by the following expression: tan ? (103 to 104 Hz)?0.0060 where the loss tangent tan ? is represented by ??/?? where ?? denotes dielectric loss factor and ?? denotes dielectric constant, and tan ? (103 to 104 Hz) denotes the loss tangent in a frequency range of 103 to 104 Hz; and a ratio of tan ? (105 Hz) to tan ? (5×104 Hz) is represented by the following expression: 1.05?tan ? (105 Hz)/tan ? (5×104 Hz)?1.Type: ApplicationFiled: September 14, 2005Publication date: January 19, 2006Applicant: Canon Kabushiki KaishaInventors: Nobuyoshi Sugahara, Takaaki Kohtaki, Yasuhiro Ichikawa, Tetsuya Ida, Kazuhiko Hayami, Nozomu Komatsu
-
Patent number: 6783910Abstract: A toner for electrostatic imaging has a vinyl resin binder with an acid value of 2.5-70 mgKOH/g and (i) a long-chain alcohol with an OH value of 10-120 mg/KOH/g or (ii) a long-chain alkyl carboxylic acid with an acid value of 5-120 mg/KOH/g, wherein the acid value of the resin binder+either (i) OH value of the alcohol or (ii) acid value of the acid>(¼)×OH value of the binder.Type: GrantFiled: December 12, 2002Date of Patent: August 31, 2004Assignee: Canon Kabushiki KaishaInventors: Takaaki Kohtaki, Makoto Unno, Yushi Mikuriya, Tadashi Doujo
-
Publication number: 20040058264Abstract: To provide a black toner having excellent charging property and transferring property against a severe environmental change. The black toner includes toner particle containing at least a binder resin, carbon black and a releasing agent, wherein: the toner particles have a weight-average particle diameter of 3.5 to 8.0 &mgr;m; total amount of acid value and hydroxyl value of the toner is 30 to 75 mgKOH/g; average circularity of particles contained in the toner having circle-equivalent diameter of 2 &mgr;m or more is 0.915 to 0.Type: ApplicationFiled: July 30, 2003Publication date: March 25, 2004Inventors: Nobuyoshi Sugahara, Takaaki Kohtaki, Yasuhiro Ichikawa, Tetsuya Ida, Kazuhiko Hayami, Nozomu Komatsu
-
Publication number: 20030211414Abstract: A toner for electrostatic imaging has a vinyl resin binder with an acid value of 2.5-70 mgKOH/g and (i) a long-chain alcohol with an OH value of 10-120 mg/KOH/g or (ii) a long-chain alkyl carboxylic acid with an acid value of 5-120 mg/KOH/g, wherein the acid value of the resin binder+either (i) OH value of the alcohol or (ii) acid value of the acid>(¼)×OH value of the binder.Type: ApplicationFiled: December 12, 2002Publication date: November 13, 2003Inventors: Takaaki Kohtaki, Makoto Unno, Yushi Mikuriya, Tadashi Doujo
-
Patent number: 6623901Abstract: A toner for developing an electrostatic image is constituted by a binder resin and a long-chain compound. The binder resin is a polyester resin or vinyl resin respectively having an acid value of preferably 25-70 mgKOH/g. The long-chain compound is a long-chain alkyl alcohol having an OH value of 10-120 mgKOH/g or a long-chain alkyl carboxylic acid having an acid value of 5-120 mgKOH/g and is contained so as to satisfy a condition of the following formula (1) or formula (2): Formula (1) acid value of binder resin +OH value of long-chain alkyl alcohol >(¼)×OH value of binder resin, or Formula (2) acid value of binder resin +acid value of long-chain alkyl carboxylic acid >(¼)×OH value of binder resin. The toner is characterized by a good balance between fixing performances and developing performances suitable for a variety of models of image forming apparatus and in wide ranges of environmental conditions.Type: GrantFiled: December 18, 1997Date of Patent: September 23, 2003Assignee: Canon Kabushiki KaishaInventors: Takaaki Kohtaki, Makoto Unno, Yushi Mikuriya, Tadashi Doujo
-
Patent number: 6586147Abstract: A toner, particularly a color toner suitable for full-color image formation through a substantially oil-less heat-pressure fixing device, is formed from at least a binder resin, a colorant and a wax. The toner has viscoelasticity including: a storage modulus at 80° C. (G′80) in a range of 1×106-1×1010 dN/m2, storage moduli at temperatures of 120-180° C. (G′120-180) in a range of 5×103-1×106 dN/m2, and loss tangents (tan &dgr;=G″/G′ as a ratio between G″ (loss modulus) and G′ (storage molecules)) including a loss tangent at 180° C. (tan &dgr;180) and a minimum of loss tangents over a temperature range of 120-180 ° C. (tan &dgr;min) satisfying 1≦tan &dgr;180/tan &dgr;min. The toner further exhibits a thermal behavior providing a heat-absorption curve according to differential scanning calorimetry (DSC) showing a maximum heat-absorption peak temperature in a range of 50-110° C. in a temperature range of 30-200° C.Type: GrantFiled: July 9, 2001Date of Patent: July 1, 2003Assignee: Canon Kabushiki KaishaInventors: Wakashi Iida, Takaaki Kohtaki, Nobuyoshi Sugawara, Takayuki Itakura, Yojiro Hotta
-
Patent number: 6528222Abstract: A toner, particularly a color toner suitable for full-color image formation through a substantially oil-less heat-pressure fixing device, is formed from at least a binder resin, a colorant and a wax. The binder resin comprises a polyester-based resin selected from the group consisting of (a) a polyester resin, (b) a hybrid resin having a polyester unit and a vinyl polymer unit, and (c) a mixture of these resins. The wax is characterized by including a structural unit including an OH group, an amide, or an ester group at a specific position.Type: GrantFiled: July 9, 2001Date of Patent: March 4, 2003Assignee: Canon Kabushiki KaishaInventors: Takaaki Kohtaki, Wakashi Iida, Nobuyoshi Sugahara, Takayuki Itakura, Yojiro Hotta
-
Publication number: 20020072005Abstract: A toner, particularly a color toner suitable for full-color image formation through a substantially oil-less heat-pressure fixing device, is formed from at least a binder resin, a colorant and a wax. The binder resin comprises a polyester-based resin selected from the group consisting of (a) a polyester resin, (b) a hybrid resin having a polyester unit and a vinyl polymer unit, and (c) a mixture of these resins. The wax is characterized by including a structural unit including an OH group, an amide, or an ester group at a specific position.Type: ApplicationFiled: July 9, 2001Publication date: June 13, 2002Inventors: Takaaki Kohtaki, Wakashi Iida, Nobuyoshi Sugahara, Takayuki Itakura, Yojiro Hotta
-
Publication number: 20020051924Abstract: A toner, particularly a color toner suitable for full-color image formation through a substantially oil-less heat-pressure fixing device, is formed from at least a binder resin, a colorant and a wax. The toner has viscoelasticity including: a storage modulus at 80° C. (G′80) in a range of 1×106-1×1010 dN/m2, storage moduli at temperatures of 120-180 ° C. (G′120-180) in a range of 5×103-1×106 dN/m2, and loss tangents (tan &dgr;=G″/G′ as a ratio between G″ (loss modulus) and G′ (storage molecules)) including a loss tangent at 180° C. (tan &dgr;180) and a minimum of loss tangents over a temperature range of 120-180 ° C. (tan &dgr;min) satisfying 1≦tan &dgr;180/tan &dgr;min. The toner further exhibits a thermal behavior providing a heat-absorption curve according to differential scanning calorimetry (DSC) showing a maximum heat-absorption peak temperature in a range of 50-110 ° C. in a temperature range of 30-200° C.Type: ApplicationFiled: July 9, 2001Publication date: May 2, 2002Inventors: Wakashi Iida, Takaaki Kohtaki, Nobuyoshi Sugahara, Takayuki Itakura, Yojiro Hotta
-
Patent number: 6365314Abstract: A toner for developing electrostatic images. having a uniform composition and uniform performances over varying sizes of toner particles is constituted by (a) a binder resin, (b) a long-chain alkyl compound and (c) a specific azo-type iron complex. The long-chain alkyl compound is represented by the following formula (1), (2) or (3): CH3&Parenopenst;CH2&Parenclosest;xCH2OH (1), CH3&Parenopenst;CH2&Parenclosest;yCH2COOH (3), wherein x and y independently denote an average value in the range of 35-150.Type: GrantFiled: December 9, 1999Date of Patent: April 2, 2002Assignee: Canon Kabushiki KaishaInventors: Koichi Tomiyama, Takaaki Kohtaki, Manabu Ohno, Makoto Unno, Yushi Mikuriya, Nobuyuki Okubo, Tadashi Doujo, Shunji Suzuki
-
Patent number: 6187490Abstract: A two-component developer suitable for electrophotography is formed of a toner and a resin-coated carrier. The resin-coated carrier is formed of carrier core particles and 0.01-2.0 wt. % based on the carrier core particles of a resin coating layer coating the carrier core particles. The resin-coated carrier has an average particle size of 25-55 &mgr;m and the carrier core particles comprise a ferrite component represented by formula (I) below: (Fe2O3)a(MnO)b(MgO)c(A)d (I), wherein A represents a mixture of SrO, CaO and Al2O3, and a, b, c and d are numbers representing mol fractions of associated components and satisfying: 0.4<a<0.6, 0.35<b<0.45, 0.07<c<0.12, 0.005<d<0.015, and a+b+c+d≦1. Because of the specific composition, the carrier core particles are provided with a smooth surface, which is reflected into a surface smoothness of the resin-coated carrier even after coated with a thin resin coating layer.Type: GrantFiled: March 15, 2000Date of Patent: February 13, 2001Assignee: Canon Kabushiki KaishaInventors: Masaaki Taya, Takaaki Kohtaki, Yasuhiro Ichikawa
-
Patent number: 6090515Abstract: A toner for developing electrostatic images includes a binder resin, a specific long-chain alkyl compound and a specific azo iron complex. The long-chain alkyl compound contains a terminal --OH or --COOH group and from about 35 to 150 (--CH.sub.2 --) groups. The azo iron complex has a cation including 75-98 mol. % of ammonium ion and another ion which is hydrogen, sodium, potassium or mixtures thereof.Type: GrantFiled: May 23, 1997Date of Patent: July 18, 2000Assignee: Canon Kabushiki KaishaInventors: Koichi Tomiyama, Takaaki Kohtaki, Manabu Ohno, Makoto Unno, Yushi Mikuriya, Nobuyuki Okubo, Tadashi Doujo, Shunji Suzuki
-
Patent number: 5858597Abstract: A toner for developing an electrostatic image is constituted by toner particles containing at least a binder resin and a colorant, and particles containing at least one double oxide. The double oxide includes a double oxide (A) represented by the following formula (1):M.sub.a Si.sub.b O.sub.c (1),wherein M denotes a metallic element selected from the group consisting of Sr, Mg, Zn, Co, Mn and Ce; a is an integer of 1-9; b is an integer of 1-9; and c is an integer of 3-9. The above particles including a double oxide (A) are effective in improving flowability and triboelectric chargeability of the toner and providing a resultant image with excellent image qualities.Type: GrantFiled: August 30, 1996Date of Patent: January 12, 1999Assignee: Canon Kabushiki KaishaInventors: Yuichi Mizoh, Takaaki Kohtaki, Yushi Mikuriya, Tadashi Doujo
-
Patent number: 5660963Abstract: A toner for developing an electrostatic image is constituted by a resin composition and a colorant. The resin composition includes a high-softening point polyester resin (I) having a softening point of 120.degree.-180.degree. C. a low-softening point polyester resin (II) having a softening point of 80.degree.-120.degree. C., and a long-chain alkyl compound selected from the group consisting of-a long-chain alkyl alcohol principally comprising long-chain alkyl alcohol components having long-chain alkyl groups of 23 to 252 carbon atoms and a long-chain alkyl carboxylic acid principally comprising long-chain alkyl carboxylic acid components having long-chain alkyl groups of 22 to 251 carbon atoms. The resin composition preferably includes a tetrahydrofuran (THF)-soluble content providing a gel permeation chromatogram showing a weight-average molecular weight (Mw) of at least 10.sup.Type: GrantFiled: November 28, 1995Date of Patent: August 26, 1997Assignee: Canon Kabushiki KaishaInventors: Tadashi Doujo, Takaaki Kohtaki, Makoto Unno, Yushi Mikuriya
-
Patent number: 5578408Abstract: A toner for developing an electrostatic image is constituted by a binder resin and a colorant. The toner is characterized by a percentage change .sub.G' of at most 50% as calculated by the following formula (1):.gamma..sub.G' =(1-G'.sub.50% /G'.sub.1%).times.100 (1),wherein .gamma..sub.G' denotes a percentage change of storage modulus, G'.sub.50% denotes a storage modulus at 50% strain at 150.degree. C., and G'.sub.1% denotes a storage modulus at 1% strain at 150.degree. C.; a percentage change .gamma..sub.G" of at most 50% as calculated by the following formula (2):.gamma..sub.G" =(1-G".sub.50% /G".sub.1%).times.100 (2),wherein .gamma..sub.G" denotes a percentage change of loss modulus, G".sub.50% denotes a loss modulus at 50% strain, and G".sub.1% denotes a loss modulus at 1% strain; and a storage modulus G' of 3.times.10.sup.3 -7.times.10.sup.4 dyn/cm.sup.2 in a range of 1-50% strain at 150.degree. C.Type: GrantFiled: December 29, 1994Date of Patent: November 26, 1996Assignee: Canon Kabushiki KaishaInventors: Takaaki Kohtaki, Masaaki Taya, Makoto Unno, Tadashi Doujo
-
Developer containing insulating magnetic toner flowability-improving agent and inorganic fine powder
Patent number: 5547796Abstract: A developer for developing an electrostatic image is constituted by an insulating magnetic toner, inorganic fine powder and a flowability-improving agent having a BET specific surface area of at least 30 m.sup.2 /g. The insulating magnetic toner has a weight-average particle size (t-D.sub.4) of 4-14 .mu.m, a number-average particle size (t-D.sub.1) of 1-10 .mu.m, and a ratio (t-D.sub.4)/(t-D.sub.1) of 1.01-2. The inorganic fine powder has a weight-average particle size (m-D.sub.4) of 0.6-5 .mu.m, a number-average particle size (m-D.sub.1) of 0.5-4 .mu.m, and a ratio (m-D.sub.4)/(m-D.sub.1) which is in the range of 1.0-2.4 and is equal to or larger than the ratio (t-D.sub.4)/(t-D.sub.1). The inorganic fine powder is contained in an amount which is 2-8 times that of the flowability-improving agent by weight. The developer is able to retain stable developing performances by effecting suppressing preferential consumption of a particular particle size fraction in a long term of successive copying.Type: GrantFiled: July 18, 1994Date of Patent: August 20, 1996Assignee: Canon Kabushiki KaishaInventors: Takaaki Kohtaki, Masaaki Taya, Masami Fujimoto -
Patent number: 5483327Abstract: An image forming apparatus and a process cartridge includes a toner for developing an electrostatic image that is constituted by at least a binder resin and a charge control agent. The binder resin has an acid value of 5-50. The charge control agent includes an iron complex represented by the following formula: ##STR1## wherein X.sub.1 and X.sub.2 independently denote hydrogen atom, lower alkyl group, lower alkoxy group, nitro group or halogen atom; m and m' denote an integer of 1-3; R.sub.1 and R.sub.3 independently denote hydrogen atom, C.sub.1-18 alkyl or alkenyl, sufonamide, mesyl, sulfonic acid group, carboxy ester group, hydroxy, C.sub.1-18 alkoxy, acetylamino, benzoylamino or halogen atom; n and n' denote an integer of 1-3; R.sub.2 and R.sub.4 denote hydrogen atom or nitro group; and A.sup.+ denotes hydrogen ion, sodium ion, potassium ion or ammonium ion. The toner has a weight-average particle size (D.sub.4) of 4-9 .mu.m and including toner particles having a particle size of 5 .mu.Type: GrantFiled: March 6, 1995Date of Patent: January 9, 1996Assignee: Canon Kabushiki KaishaInventors: Masaaki Taya, Takaaki Kohtaki, Makoto Unno, Tadashi Doujo