Patents by Inventor Katsuhisa Yamazaki
Katsuhisa Yamazaki 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: 8501377Abstract: Provided is a magnetic toner capable of providing a stable image by suppressing sleeve contamination even under a high-temperature and high-humidity environment and under a normal-temperature and low-humidity environment and further suppressing large-particle fogging caused after the toner is left alone for a week. The magnetic toner contains toner particles, each of which contains a binder resin and a magnetic iron oxide particle, in which the binder resin has a polyester unit, the toner has i) a dielectric loss factor at 40° C. and 100 kHz of 0.50 pF/m or more but 0.90 pF/m or less, and ii) a true specific gravity of 1.50 g/cm3 or more but 1.85 g/cm3 or less.Type: GrantFiled: January 19, 2012Date of Patent: August 6, 2013Assignee: Canon Kabushiki KaishaInventors: Toru Takahashi, Katsuhisa Yamazaki, Shuhei Moribe, Daisuke Tsujimoto, Masami Fujimoto
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Patent number: 8293447Abstract: An object of the present invention is to provide a toner which allows fixation at low temperatures, which is excellent in anti-offset ability, and which provides a high quality image at high and low humidities in a stable manner without causing any image defect over time. Provided is a toner, containing at least a binder resin and a colorant in which: the binder resin in the toner contains 60% by mass or more of a styrene/acryl resin and a THF-insoluble fraction A which is an extraction residue obtained by carrying out Soxhlet extraction with tetrahydrofuran (THF) for 16 hours; the THF-insoluble fraction A contains a TOL-insoluble fraction B which is an extraction residue obtained by carrying out Soxhlet extraction with toluene (TOL) for 16 hours; and a mass ratio (B/A) between the THF-insoluble fraction A and the TOL-insoluble fraction B is in the range of 0.1?B/A?0.5.Type: GrantFiled: June 22, 2011Date of Patent: October 23, 2012Assignee: Canon Kabushiki KaishaInventors: Katsuhisa Yamazaki, Masami Fujimoto, Masaaki Taya
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Publication number: 20120196219Abstract: Provided is a magnetic toner capable of preventing electrostatic offset while attaining a high image quality by a high speed machine. The magnetic toner comprises magnetic toner particles, each of which contains a binder resin and a magnetic material, and a fine inorganic powder, in which the binder resin contains a polyester unit, and the magnetic toner has a dielectric loss factor at 40° C. and 100 kHz of 0.40 pF/m or more but 1.00 pF/m or less and a dielectric loss factor at 150° C. and 100 kHz of 0.50 pF/m or more but 4.00 pF/m or less.Type: ApplicationFiled: January 19, 2012Publication date: August 2, 2012Applicant: CANON KABUSHIKI KAISHAInventors: Shuhei Moribe, Katsuhisa Yamazaki, Toru Takahashi, Daisuke Tsujimoto, Masami Fujimoto
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Publication number: 20120196220Abstract: Provided is a magnetic toner capable of providing a stable image by suppressing sleeve contamination even under a high-temperature and high-humidity environment and under a normal-temperature and low-humidity environment and further suppressing large-particle fogging caused after the toner is left alone for a week. The magnetic toner contains toner particles, each of which contains a binder resin and a magnetic iron oxide particle, in which the binder resin has a polyester unit, the toner has i) a dielectric loss factor at 40° C. and 100 kHz of 0.50 pF/m or more but 0.90 pF/m or less, and ii) a true specific gravity of 1.50 g/cm3 or more but 1.85 g/cm3 or less.Type: ApplicationFiled: January 19, 2012Publication date: August 2, 2012Applicant: CANON KABUSHIKI KAISHAInventors: Toru Takahashi, Katsuhisa Yamazaki, Shuhei Moribe, Daisuke Tsujimoto, Masami Fujimoto
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Patent number: 8057977Abstract: Provide is a toner including toner particles each containing at least a binder resin and a colorant, and an inorganic fine powder, in which the inorganic fine powder has a ratio (A/B) of a total pore volume A measured in a pore diameter range of from 1.9 nm or more and to 8.0 nm or less to a total pore volume B measured in a pore diameter range of from 1.9 nm or more and to 300.0 nm or less of from 0.20 or more and to 1.00 or less, and the total pore volume A is from 1.00×10?2 cm3/g or more and to 1.00 cm3/g or less.Type: GrantFiled: November 11, 2008Date of Patent: November 15, 2011Assignee: Canon Kabushiki KaishaInventors: Syuhei Moribe, Katsuhisa Yamazaki, Daisuke Yoshiba, Masami Fujimoto
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Publication number: 20110256480Abstract: An object of the present invention is to provide a toner which allows fixation at low temperatures, which is excellent in anti-offset ability, and which provides a high quality image at high and low humidities in a stable manner without causing any image defect over time. Provided is a toner, containing at least a binder resin and a colorant in which: the binder resin in the toner contains 60% by mass or more of a styrene/acryl resin and a THF-insoluble fraction A which is an extraction residue obtained by carrying out Soxhlet extraction with tetrahydrofuran (THF) for 16 hours; the THF-insoluble fraction A contains a TOL-insoluble fraction B which is an extraction residue obtained by carrying out Soxhlet extraction with toluene (TOL) for 16 hours; and a mass ratio (B/A) between the THF-insoluble fraction A and the TOL-insoluble fraction B is in the range of 0.1?B/A?0.5.Type: ApplicationFiled: June 22, 2011Publication date: October 20, 2011Applicant: CANON KABUSHIKI KAISHAInventors: Katsuhisa Yamazaki, Masami Fujimoto, Masaaki Taya
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Patent number: 8026030Abstract: The present invention provides a toner which is excellent in low-temperature fixability and transparency and has high gloss, and which is excellent in offset resistance, storage stability, and development stability. The toner is characterized in that: a square radius of inertia Rt at a peak top of a main peak in GPC-RALLS-viscometer analysis of tetrahydrofuran (THF) soluble matter when the toner is dissolved in a THF solvent at 25° C. for 24 hours is 1.0 nm to 3.8 nm; and the square radius of inertia Rt and a square radius of inertia Rp at a peak top of a main peak in GPC-RALLS-viscometer analysis of THF soluble matter when linear polystyrene, having an absolute peak molecular weight value at the same value as a main peak value of the toner, is dissolved in a THF solvent at 25° C. for 24 hours satisfy the relationship of Rt/Rp<0.85.Type: GrantFiled: November 3, 2006Date of Patent: September 27, 2011Assignee: Canon Kabushiki KaishaInventors: Syuhei Moribe, Katsuhisa Yamazaki, Shuichi Hiroko
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Publication number: 20110097655Abstract: Provided is an image-forming method, the method including: forming an electrostatic image on an electrostatic image bearing member which has been charged; developing the electrostatic image to form a toner image; transferring the toner image on the electrostatic image bearing member with or without mediating an intermediate transferring member onto a transfer material; and fixing the toner image on the transfer material, in which: the electrostatic image hearing member is a photosensitive member obtained by sequentially laminating a photoconductive layer and a surface layer formed of hydrogenated amorphous silicon carbide, and a sum of an atomic density of silicon atoms and an atomic density of carbon atoms in the surface layer of the photosensitive member is 6.60×1022 atoms/cm3 or more; and the toner has a binder resin and magnetic iron oxide particles, and the magnetic iron oxide particles contain Fe(2+) at a content of 20.0 mass % or more and 25.0 mass % or lees.Type: ApplicationFiled: July 24, 2009Publication date: April 28, 2011Applicant: Canon Kabushiki KaishaInventors: Tooru Takahashi, Katsuhisa Yamazaki, Syuhei Moribe, Daisuke Yoshiba, Masami Fujimoto
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Patent number: 7897316Abstract: Provided is a toner including at least: a binder resin; and a colorant, in which: the binder resin contains at least a polyester unit and a vinyl copolymer unit; a main peak MpA is present in the molecular weight region of 2,000 to 7,000 in a molecular weight distribution measured by means of gel permeation chromatography (GPC) of a specific tetrahydrofuran (THF) soluble matter A measured by a specific method; a main peak MpB is present in the molecular weight region of 5,000 to 10,000 in a molecular weight distribution measured by means of GPC of a specific THF soluble matter B which contains a component of a molecular weight region of 100,000 or less in range from 70 to 100 mass %, and the peak molecular weight MpA of the THF soluble matter A and the peak molecular weight MpB of the THF soluble matter B satisfy a specific equation.Type: GrantFiled: July 24, 2006Date of Patent: March 1, 2011Assignee: Canon Kabushiki KaishaInventors: Katsuhisa Yamazaki, Masami Fujimoto, Shuichi Hiroko, Masaaki Taya
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Patent number: 7855042Abstract: To provide a developer and an image forming method with each of which a high-resolution, high-definition image can be stably obtained over a long time period irrespective of an environment. The present invention provides a developer including at least: toner particles each containing at least a binder resin; and a composite inorganic fine powder, the developer being characterized in that: the composite inorganic fine powder has a peak at a Bragg angle (2?±0.20 deg) of each of 32.20 deg, 25.80 deg, and 27.50 deg in a CuK? characteristic X-ray diffraction pattern; and the half width of the X-ray diffraction peak at a Bragg angle (2?±0.20 deg) of 32.20 deg is 0.20 to 0.30 deg.Type: GrantFiled: May 30, 2007Date of Patent: December 21, 2010Assignee: Canon Kabushiki KaishaInventors: Takakuni Kobori, Kenji Okado, Masami Fujimoto, Katsuhisa Yamazaki, Syuhei Moribe, Daisuke Yoshiba
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Patent number: 7842447Abstract: To provide a toner which allows low temperature fixation irrespective of the configuration of a fuser, which is excellent in offset resistance, and which provides high image quality at high and low humidities in a stable manner without causing any image defect over time. A toner containing: a binder resin and a colorant; in which the toner contains a THF-soluble component to be dissolved in tetrahydrofuran (THF); the binder resin component contained in the THF-soluble component contains: a vinyl resin unit (I) formed by at least a carboxyl group-containing vinyl resin and an epoxy group-containing vinyl resin and having an epoxy value of 0.001 to 1.Type: GrantFiled: December 6, 2005Date of Patent: November 30, 2010Assignee: Canon Kabushiki KaishaInventors: Katsuhisa Yamazaki, Masami Fujimoto, Daisuke Yoshiba
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Patent number: 7740998Abstract: A positively chargeable developer is provided which is capable of providing stable image quality without causing any image defect even in long-term use. The developer includes at least positively chargeable toner particles each containing at least a binder resin and magnetic iron oxide, silica and an inorganic fine powder. A unconfined yield strength at a major consolidation stress of 5 kPa of the developer is in the range of 0.1 to 2.5 kPa, and a unconfined yield strength at a major consolidation stress of 20 kPa of the developer is in the range of 2.5 to 5.5 kPa.Type: GrantFiled: February 16, 2006Date of Patent: June 22, 2010Assignee: Canon Kabushiki KaishaInventors: Katsuhisa Yamazaki, Daisuke Yoshiba, Masami Fujimoto
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Patent number: 7700254Abstract: The present invention aims to provide a toner having excellent developability and excellent low-temperature fixability without causing adhesion of ejected sheets even in a high-speed oilless fixing system and capable of preventing a frameless printing from causing a twisted offseting phenomenon. Specifically, provided is a toner having toner particles including at least a binder resin and a colorant, in which, when the toner is dissolved in a tetrahydrofuran (THF) solvent at 25° C. for 24 hours, the ratio of a THF-soluble matter having an intrinsic viscosity of 5.0×10?2 dl/g or less with respect to the total amount of the THF-soluble matter in a GPC-RALLS-viscometer analysis is 15.0 mass % to 60.0 mass %, and the ratio of a THF-soluble matter having an intrinsic viscosity of 1.5×10?1 dl/g or more with respect to the total amount of the THF-soluble matter in a GPC-RALLS-viscometer analysis is 20.0 mass % to 40.0 mass %.Type: GrantFiled: March 27, 2008Date of Patent: April 20, 2010Assignee: Canon Kabushiki KaishaInventors: Syuhei Moribe, Katsuhisa Yamazaki, Daisuke Yoshiba, Hirata Junko, Masami Fujimoto, Takashige Kasuya
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Patent number: 7638251Abstract: The invention provides a toner which is excellent in its low-temperature fixing property and high-temperature offset resistance regardless of the types of paper, and constantly provides high-quality images regardless of environments and does not generate image defects even after prolonged use. In a master curve of the toner at a reference temperature of 150° C., a difference between a storage modulus at a frequency of 0.1 Hz and a storage modulus at a frequency of 1000 Hz is set in a rage from 0 to 2.5×105 Pa, where the activation energy determined from a shift factor is brought to a range from 50 to 130 kJ/mol.Type: GrantFiled: February 6, 2007Date of Patent: December 29, 2009Assignee: Canon Kabushiki KaishaInventors: Katsuhisa Yamazaki, Shuichi Hiroko, Shuhei Moribe
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Patent number: 7544455Abstract: A magnetic toner having magnetic toner particles each containing at least a binder resin and a magnetic iron oxide particle, in which: when a solution is prepared by dissolving the magnetic iron oxide particles in an acidic aqueous solution and an Fe element amount in a solution in which all the magnetic iron oxide particles are dissolved is defined as a total Fe element amount, a ratio X of the amount of Fe(2+) in a solution in which the magnetic iron oxide particles are dissolved to a state where 10 mass % of the total Fe element amount is present in the solution (solution having an Fe element-dissolving ratio of 10 mass %) to an Fe element amount in the solution having a specific Fe element-dissolving ratio; and the dielectric loss tangents of the magnetic toner measured at a temperature of 40° C. satisfy specific conditions.Type: GrantFiled: July 24, 2008Date of Patent: June 9, 2009Assignee: Canon Kabushiki KaishaInventors: Daisuke Yoshiba, Katsuhisa Yamazaki
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Patent number: 7537877Abstract: A toner is provided which can stably provide a favorable density stability, line reproducibility and dot reproducibility even in high-speed copying machines, printers and the like which form high resolution latent images over a long period regardless of environmental conditions, and can provide the image quality adaptable to embedded pattern printing, QR code printing and the like. The present invention is characterized in that the toner which includes toner particles including at least a binder resin and a colorant, and a fine silica powder, has a volume median diameter (D50) of not less than 0.70 ?m and not more than 3.00 ?m, and a total pore volume of not more than 0.200 cm3/g, measured in the range of the pore diameter from not less than 1.7 nm and not more than 300.0 nm.Type: GrantFiled: November 29, 2007Date of Patent: May 26, 2009Assignee: Canon Kabushiki KaishaInventors: Daisuke Yoshiba, Katsuhisa Yamazaki, Syuhei Moribe, Junko Nishiyama, Shuichi Hiroko, Masami Fujimoto, Takashige Kasuya
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Publication number: 20090123859Abstract: Provide is a toner including toner particles each containing at least a binder resin and a colorant, and an inorganic fine powder, in which the inorganic fine powder has a ratio (A/B) of a total pore volume A measured in a pore diameter range of from 1.9 nm or more and to 8.0 nm or less to a total pore volume B measured in a pore diameter range of from 1.9 nm or more and to 300.0 nm or less of from 0.20 or more and to 1.00 or less, and the total pore volume A is from 1.00×10?2 cm3/g or more and to 1.00 cm3/g or less.Type: ApplicationFiled: November 11, 2008Publication date: May 14, 2009Applicant: CANON KABUSHIKI KAISHAInventors: Syuhei Moribe, Katsuhisa Yamazaki, Daisuke Yoshiba, Masami Fujimoto
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Publication number: 20080286676Abstract: A magnetic toner having magnetic toner particles each containing at least a binder resin and a magnetic iron oxide particle, in which: when a solution is prepared by dissolving the magnetic iron oxide particles in an acidic aqueous solution and an Fe element amount in a solution in which all the magnetic iron oxide particles are dissolved is defined as a total Fe element amount, a ratio X of the amount of Fe(2+) in a solution in which the magnetic iron oxide particles are dissolved to a state where 10 mass % of the total Fe element amount is present in the solution (solution having an Fe element-dissolving ratio of 10 mass %) to an Fe element amount in the solution having a specific Fe element-dissolving ratio; and the dielectric loss tangents of the magnetic toner measured at a temperature of 40° C. satisfy specific conditions.Type: ApplicationFiled: July 24, 2008Publication date: November 20, 2008Applicant: CANON KABUSHIKI KAISHAInventors: Daisuke Yoshiba, Katsuhisa Yamazaki
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Publication number: 20080187853Abstract: The present invention aims to provide a toner having excellent developability and excellent low-temperature fixability without causing adhesion of ejected sheets even in a high-speed oilless fixing system and capable of preventing a frameless printing from causing a twisted offseting phenomenon. Specifically, provided is a toner having toner particles including at least a binder resin and a colorant, in which, when the toner is dissolved in a tetrahydrofuran (THF) solvent at 25° C. for 24 hours, the ratio of a THF-soluble matter having an intrinsic viscosity of 5.0×10?2 dl/g or less with respect to the total amount of the THF-soluble matter in a GPC-RALLS-viscometer analysis is 15.0 mass % to 60.0 mass %, and the ratio of a THF-soluble matter having an intrinsic viscosity of 1.5×10?1 dl/g or more with respect to the total amount of the THF-soluble matter in a GPC-RALLS-viscometer analysis is 20.0 mass % to 40.0 mass %.Type: ApplicationFiled: March 27, 2008Publication date: August 7, 2008Applicant: CANON KABUSHIKI KAISHAInventors: Syuhei Moribe, Katsuhisa Yamazaki, Daisuke Yoshiba, Junko Hirata, Masami Fujimoto, Takashige Kasuya
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Publication number: 20080124643Abstract: A toner is provided which can stably provide a favorable density stability, line reproducibility and dot reproducibility even in high-speed copying machines, printers and the like which form high resolution latent images over a long period regardless of environmental conditions, and can provide the image quality adaptable to embedded pattern printing, QR code printing and the like. The present invention is characterized in that the toner which includes toner particles including at least a binder resin and a colorant, and a fine silica powder, has a volume median diameter (D50) of not less than 0.70 ?m and not more than 3.00 ?m, and a total pore volume of not more than 0.200 cm3/g, measured in the range of the pore diameter from not less than 1.7 nm and not more than 300.0 nm.Type: ApplicationFiled: November 29, 2007Publication date: May 29, 2008Applicant: CANON KABUSHIKI KAISHAInventors: Daisuke Yoshiba, Katsuhisa Yamazaki, Syuhei Moribe, Junko Nishiyama, Shuichi Hiroko, Masami Fujimoto, Takashige Kasuya