Patents by Inventor Tadashi Doujo
Tadashi Doujo 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: 6953646Abstract: A toner comprises toner particles comprising at least a binder resin, a colorant, and a sulfur-containing resin, in which the toner particles comprise the sulfur-containing resin so as to satisfy a relation of; 0.50?IS/TS?0.95 where TS denotes a content of sulfur in the toner particles, and IS denotes a content of sulfur in isopropyl alcohol insoluble components of the toner particles, whereby it is possible to obtain a high quality image having an excellent developing resistance regardless of the surrounding conditions and a uniform charge amount distribution regardless of processing speed.Type: GrantFiled: May 14, 2003Date of Patent: October 11, 2005Assignee: Canon Kabushiki KaishaInventors: Tadashi Doujo, Yuichi Mizoh, Nene Shibayama, Yusuke Hasegawa
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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
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Publication number: 20040013962Abstract: A toner comprises toner particles comprising at least a binder resin, a colorant, and a sulfur-containing resin, in which the toner particles comprise the sulfur-containing resin so as to satisfy a relation of; 0.50≦IS/TS≦0.95 where TS denotes a content of sulfur in the toner particles, and IS denotes a content of sulfur in isopropyl alcohol insoluble components of the toner particles, whereby it is possible to obtain a high quality image having an excellent developing resistance regardless of the surrounding conditions and a uniform charge amount distribution regardless of processing speed.Type: ApplicationFiled: May 14, 2003Publication date: January 22, 2004Inventors: Tadashi Doujo, Yuichi Mizoh, Nene Shibayama, Yusuke Hasegawa
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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
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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
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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
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Patent number: 6232027Abstract: A toner having a negative triboelectric chargeability is constituted by at least a binder resin, a colorant and an organic metal compound. The toner is characterized by: (a) the organic metal compound is an organic zirconium compound comprising a coordination or/and a bonding of zirconium and an aromatic compound as a ligand or/and an acid source selected from the group consisting of aromatic diols, aromatic hydroxycarboxylic acids, aromatic monocarboxylic acids, and aromatic polycarboxylic acids, (b) the binder resin is a resin selected from the group consisting of (i) a polyester resin and (ii) a hybrid resin component comprising a polyester unit and a vinyl polymer unit, (c) the binder resin has an acid value of 2-50 mgKOH/g, and (d) the toner contains a TFT (tetrahydrofuran)-soluble content providing a GPC (gel permeation chromatography) chromatogram exhibiting a main peak in a molecular weight range of 3,000-20,000 and including 3-25% of a component having molecular weights of at least 5×105.Type: GrantFiled: May 26, 1999Date of Patent: May 15, 2001Assignee: Canon Kabushiki KaishaInventors: Satoshi Matsunaga, Toshiaki Nakahara, Yuichi Mizoh, Hirohide Tanikawa, Minekazu Endo, Tadashi Doujo, Nene Shibayama
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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
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Patent number: 6040103Abstract: A toner for developing an electrostatic image is composed of toner particles each containing at least a binder resin, a colorant, and a wax. The wax satisfies conditions of:(a) showing a maximum heat-absorption peak in a region of 50-130.degree. C. on temperature increase on a DSC (differential scanning calorimeter) curve, and(b) giving a .sup.13 C-NMR (nuclear magnetic resonance) spectrum showing a total peak area S in a range of 0-50 ppm, a total peak area S1 in a range of 36-42 ppm and a total peak area S2 in a range of 10-17 ppm satisfying:1.0.ltoreq.(S1/S).times.100.ltoreq.10, 1.5.ltoreq.(S2/S).times.100.ltoreq.15, and S1<S2.The wax satisfying the above-conditions has an appropriately branched long-chain structure and provides the toner with a good balance of good low-temperature fixability and anti-hot-temperature offset characteristic.Type: GrantFiled: September 2, 1997Date of Patent: March 21, 2000Assignee: Canon Kabushiki KaishaInventors: Manabu Ohno, Takeshi Ohtake, Satoshi Matsunaga, Tadashi Doujo
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Patent number: 6017669Abstract: The toner for developing an electrostatic image has toner particles containing at least binder resin and colorant. The resin components of a range of 2,000 to 100,000 in molecular weight, prepared by preparatory liquid chromatograph from the binder resin, exhibit an M/S ratio of 200 or greater and are 50% to 90% in abundance. The M and S stand for a weight average molecular weight (M) measured by means of light scattering method and an inertia radius (S) measured by means of light scattering method, respectively.Type: GrantFiled: September 18, 1996Date of Patent: January 25, 2000Assignee: Canon Kabushiki KaishaInventors: Makoto Unno, Takaaki Kotaki, Yushi Mikuriya, Tadashi Doujo
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Patent number: 5976752Abstract: An electrophotographic toner is composed of at least a binder resin, a colorant, and a wax. The binder resin (a) comprises a polyester resin, a vinyl resin and a hybrid resin component comprising a polyester unit and a vinyl polymer unit, (b) has a THF (tetrahydrofuran)-soluble content (W1) of 50-85 wt. % and a THF-insoluble content (W2) of 5-50 wt. %, an ethyl acetate-soluble content (W3) of 40-98 wt. % and an ethyl acetate-insoluble content (W4) of 2-60 wt. %, a chloroform-soluble content (W5) of 55-90 wt. % and a chloroform-insoluble content (W6) of 10-45 wt. %, respectively after 10 hours of Soxhlet extraction with respective solvents, giving a ratio W4/S6 of 1.1-4.0, and contains a THF-soluble content providing a GPC (gel permeation chromatography) chromatogram exhibiting a main peak in a molecular weight range of 4000-9000, including 35.0-65.0% (A1) of a component haing molecular weights in a range of 500 to below 1.times.10.sup.4, 25.0-45.0% (A2) of a component having molecular weights in a range of 1.Type: GrantFiled: August 18, 1998Date of Patent: November 2, 1999Assignee: Canon Kabushiki KaishaInventors: Satoshi Matsunaga, Koichi Tomiyama, Yuichi Mizoh, Keita Nozawa, Minekazu Endo, Tadashi Doujo, Yoshihiro Ogawa, Nene Shibayama
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Patent number: 5955234Abstract: A toner for developing an electrostatic image is comprised of a binder resin, a colorant and a wax. The toner has the following rheological characteristics: (a) a temperature at which the ratio of a loss elastic modulus to a storage elastic modulus (G"/G'=tan .delta.) comes to be 1.0 is present in a temperature range of from 55.degree. C. to 70.degree. C., with an elastic modulus being 1.5.times.10.sup.8 Pa or below; (b) the ratio of the storage elastic modulus at a temperature of 40.degree. C. (G'.sub.40) to the storage elastic modulus at a temperature of 50.degree. C. (G'.sub.50), G'.sub.40 /G'.sub.50, is from 1.5 to 5.0; (c) the ratio of the storage elastic modulus at a temperature of 50.degree. C. (G'.sub.50) to the storage elastic modulus at a temperature of 60.degree. C. (G'.sub.60), G'.sub.50 /G'.sub.60, is from 3 to 20; (d) the ratio of the storage elastic modulus at a temperature of 70.degree. C. (G'.sub.70) to the storage elastic modulus at a temperature of 100.degree. C. (G'.sub.100), G'.sub.Type: GrantFiled: October 8, 1997Date of Patent: September 21, 1999Assignee: Canon Kabushiki KaishaInventors: Satoshi Matsunaga, Manabu Ohno, Tadashi Doujo
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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
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Patent number: 5773183Abstract: A toner for developing an electrostatic image has a binder resin, a colorant and a charge control agent. The binder resin has a polyester resin having an acid value of from 15 to 40 and a hydroxyl value of 45 or less. The toner has, in its molecular weight distribution as measured by gel permeation chromatography, tetrahydrofuran-soluble matter having a weight average molecular weight Mw of 100,000 or more, having a ratio of weight average molecular weight Mw to number average molecular weight Mn, Mw/Mn, of not less than 35, containing from 70% to 94% of a low-molecular weight region component having a molecular weight of less than 150,000, containing from 1% to 10% of a medium-molecular weight region component having a molecular weight of from 150,000 to 500,000, and containing from 5% to 25% of a high-molecular weight region component having a molecular weight of more than 500,000. The high-molecular weight region component is more than the medium-molecular weight region component.Type: GrantFiled: November 15, 1996Date of Patent: June 30, 1998Assignee: Canon Kabushiki KaishaInventors: Tadashi Doujo, Yuichi Mizoo, Takaaki Kotaki, Yushi Mikuriya
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Patent number: 5695902Abstract: A toner for developing an electrostatic image is formed as a mixture of toner particles containing at least a binder resin and a colorant, and inorganic fine powder. The inorganic fine powder includes: (A) inorganic fine powder (A) treated at least with silicone oil, and (B) inorganic fine powder (B) comprising a composite metal oxide including at least Si as a constituent element and having a weight-average particle size of 0.3-5 .mu.m. Because of the inclusion of the two types of inorganic fine powders (A) and (B), the toner is stably provided with a high flowability and a high triboelectric charge under various environmental conditions including low-humidity to high-humidity conditions. The toner is suitably used in an image forming system including a contact-charging means, a contact-transfer means and a film (or surf)-fixing system.Type: GrantFiled: November 15, 1996Date of Patent: December 9, 1997Assignee: Canon Kabushiki KaishaInventors: Yushi Mikuriya, Yuichi Mizoh, Tadashi Doujo
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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
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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
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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
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Patent number: 5439770Abstract: A toner for developing an electrostatic image 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 comprises 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.m or smaller at 3-90% by number, toner particles having a particle size of 6.35-10.Type: GrantFiled: April 15, 1994Date of Patent: August 8, 1995Assignee: Canon Kabushiki KaishaInventors: Masaaki Taya, Takaaki Kohtaki, Makoto Unno, Tadashi Doujo