Canon Kabushiki Kaisha

Hiroyuki Suematsu

Manabu Ohno

Hiroshi Yusa

Koichi Tomiyama

Eiichi Imai

Hisayuki Ochi

Tetsuhito Kuwashima

Tsutomu Kukimoto

Tsuyoshi Takiguchi

Takakuni Kobori

Akihiko Nakazawa

Shunji Suzuki

Nobuyuki Okubo

Takashige Kasuya

Masayoshi Kato

Tetsuya Kuribayashi

Masaichiro Katada

Yoshihiko Hyosu

Seiichi Takagi

Yoshinobu Nagai

Yukari Ishibashi

Tsuyoshi Takuguchi

A toner is comprised of a composition containing at least a polymer component and a charge control agent. The polymer component contains substantially no tetrahydrofuran (THF)-insoluble matter. The polymer component THF-soluble has a major peak and a minor peak in the specific molecular weight regions in gel permeation chromatography (GPC). The low molecular weight component and high molecular weight component of the polymer component, each of which shows the specific molecular weight region in GPC, have the specific acid values, respectively. The difference between the acid values is in the specific range.

Process cartridge

An electrophotographic toner composition suitable for heat-fixation and showing good storage characteristics is constituted by polymer components, a colorant and a metal-containing organic compound. The toner composition shows a melt index (at 125.degree. C., 10 kg-load) of 5-25 g/10 min., and the polymer components are characterized by (a) containing substantially no THF (tetrahydrofuran)-insoluble content, (b) including a THF-soluble content thereof providing a GPC (gel permeation chromatography) chromatogram showing i) a main peak in a molecular weight region of 2.times.10.sup.3 -3.times.10.sup.4, and a sub-peak or shoulder in a molecular weight region of at least 10.sup.5, and ii) an areal percentage of 3-10% in a molecular weight region of at least 10.sup.6, and (c) including a polymer component (H) in a molecular weight region of at least 10.sup.5 obtained by polymerization using a polyfunctional polymerization initiator and a mono-functional polymerization initiator.

Image forming method employing toner containing higher and lower

The present invention relates a toner for developing electrostatic images, comprising: a resin composition, which contains a binder resin and low molecular weight wax, and a coloring agent, wherein the binder resin does not substantially contain insoluble tetrahydrofuran (THF) component, its chromatograph measured with soluble tetrahydrofuran (THF) component has a main peak in a region of a molecular weight of 2,000 to 30,000 and a subpeak or a shoulder in a high molecular weight region of a molecular weight of 100,000 or more, a ratio of weight average molecular weight (Mw)/number average molecular weight (Mn) thereof is 30 or more, the high molecular weight region has a crosslinking monomer unit as a component monomer unit and the binder resin contains high molecular weight polymer having a Mw of 1,200,000 or more polymerized by using both polyfunctional initiator and a mono-functional initiator. Moreover, the present invention relates to a method of manufacturing a resin composition for producing a toner.

Toner for developing electrostatic image and method of manufacturing

An image forming apparatus includes a member to be charged for carrying an electrostatic latent image; a contact charging means for contact charging the member to be charged and a developing means for developing the latent image. The developing means includes a developer having a magnetic toner and fine powder treated with a silicone oil or varnish-treating agent, wherein the magnetic toner particles include a binder resin and contain from 10-70 wt. % of magnetic fine powder. An image forming method includes the steps of contact charging, latent image forming and developing with a developer having the binder resin, 10 to 70 wt. % magnetic fine powder and fine powder treated with a silicone oil or varnish-treating agent.

Images forming apparatus and developer for developing electrostatic

An electrophotographic toner composition suitable for heat-fixation and showing good storage characteristics is constituted by polymer components, a colorant and a metal-containing organic compound. The toner composition shows a melt index (at 125.degree. C., 10 kg-load) of 5-25 g/10 min., and the polymer components are characterized by (a) containing substantially no THF (tetrahydrofuran)-insoluble content, (b) including a THF-soluble content thereof providing a GPC (gel permeation chromatography) chromatogram showing i) a main peak in a molecular weight region of 2.times.10.sup.3 -3.times.10.sup.4, and a sub-peak or shoulder in a molecular weight region of at least 10.sup.5, and ii) an areal percentage of 3-10% in a molecular weight region of at least 10.sup.6, and (c) including a polymer component (H) in a molecular weight region of at least 10.sup.5 obtained by polymerization using a polyfunctional polymerization initiator and a monofunctional polymerization initiator.

Toner for developing electrostatic image containing higher and lower

Toner for developing electrostatic images, process cartridge, and image

A magnetic toner is formed from a binder resin and silicon-containing magnetic iron oxide particles. The magnetic toner has a weight-average particle size of at most 13.5 .mu.m, and the magnetic toner has a particle size distribution such that magnetic toner particles having a particle size of at least 12.7 .mu.m are contained in an amount of at most 50 wt. %. The magnetic iron oxide particles have a silicon content of 0.4-2.0 wt. % based on iron, and the magnetic iron oxide particles have an Fe/Si atomic ratio of 1.2-4.0 at the utmost surfaces thereof. Because of the use of such magnetic iron oxide particles having a specifically controlled overall and surface Si contents, the magnetic toner can show stable performances even after standing in a high humidity environment.

Magnetic toner, process cartridge and image forming method

An image forming apparatus includes a member to be charged for carrying an electrostatic image, a contact-charging means for charging the member to be charged in contact with the member to be charged, and a developing means for developing the electrostatic image carried on the member to be charged. The developing means includes a developer for developing the electrostatic image comprising a toner and hydrophobic inorganic fine powder. The hydrophobic fine powder has a hydrophobicity of 60% or higher and the toner has a volume average particle size of 4-8 microns. The hydrophobic inorganic fine powder not only improves the fluidity of the developer and adjusts the chargeability of the developer but also prevents difficulties due to interaction between the member to be charged and the contact charging means in the presence of residual developer, such as damages of the member to be charged and toner-sticking onto the member to be charged.

Image forming apparatus and developer for developing electrostatic images

An image forming method, including the steps of: developing an electrostatic image formed on an electrostatic image-bearing member with a developer to form thereon thereon a developed image, the developer containing 100 wt. parts of a toner and 0.05 to 3 wt. parts of fine powder treated with a silicone oil or silicone varnish; and transferring the developed image on the electrostatic image-bearing member to a transfer material while causing a transfer device, such as a roller or belt to contact the electrostatic image-bearing member by the medium of the transfer material under a line pressure of 3 g/cm or higher.

Image forming method comprising electrostatic transfer of developed

An image forming apparatus is constituted by an image-bearing member for bearing a latent image, and a developing apparatus for developing the latent image. The developing apparatus is constituted by a developer container for containing a developer, a developer-carrying member for carrying and conveying the developer contained in the developer container to a developing zone opposite the image-bearing member, and an elastic blade for regulating the developer carried and conveyed on the developer-carrying member to a prescribed thickness to form a thin developer layer on the developer-carrying member. A developer suitable for use in the above developing apparatus is given by a toner, which comprises a binder resin composition which contains 10-70 wt. % of a THF (tetrahydrofuran)-insoluble content and the remainder of a THF-soluble content including a component with a molecular weight of 10000 or below on a GPC (gel permeation chromatography) chromatogram of the THF-soluble content constituting 10-50 wt. % of the binder resin.

Image forming apparatus

A magnetic toner for electrophotography is composed from a binder resin and a silicon-containing magnetic iron oxide. The magnetic toner has a weigh-average particle size o at most 13.5 .mu.m and has a particle size distribution such that it contains o more than 50 wt, % of magnetic toner particles having a particle size of at least 12.7 .mu.m. The magnetic toner is able to show high developing performances because of richness in fine particles and is also provided with an improved environmental stability because the magnetic iron oxide used therein contains 0.5-4 wt, % silicon (based on total iron content) and has a specific silicon distribution such that the magnetic iron oxide has a total silicon content (A), a silicon content (B) dissolved together with the magnetic iron oxide when the magnetic iron oxide is dissolved up to 20 wt, % dissolution of iron, and a superficial silicon content (C), satisfying relations of B/A=44-84% and C/A=10-55%. The performances are enhanced if the magnetic toner is blended with additives such as inorganic fine powder or resin fine particles.

Magnetic toner, magnetic developer, apparatus unit, image forming

The present invention provide a toner for developing an electrostatic image. The toner comprises a binder resin and a coloring agent. The binder resin comprises a styrene type binder resin. The amount of an aldehyde contained in the binder resin is not more than 0.005% by weight based on the weight of the toner. The binder resin is produced by a process comprising the steps of preparing a monomer composition comprising a polymerizable monomer containing at least not less than 50% by weight of a styrene monomer, and a polymerization initiator, and subjecting said monomer composition to suspension polymerization in an aqueous medium having dissolved oxygen in an amount of not more than 2.5 mg/lit to form a styrene polymer or copolymer containing an aldehyde monomer in an amount of not more than 0.01% by weight.

Electrostatic imaging apparatus and facsimile apparatus employing toner

An image forming apparatus includes a member to be charged for carrying an electrostatic image, a contact-charging means for charging the member to be charged in contact with the member to be charged, and a developing means for developing the electrostatic image carried on the member to be charged. The developing means includes a developer for developing the electrostatic image comprising a toner and hydrophobic inorganic fine powder. The hydrophobic inorganic fine powder not only improves the fluidity of the developer and adjusts the chargeability of the developer but also prevents difficulties due to interaction between the member to be charged and the contact charging means in the presence of residual developer, such as damages of the member to be charged and toner-sticking onto the member to be charged.

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Yokohama, Japan

Hiroyuki Suematsu