Canon Kabushiki Kaisha

Shuichi Hiroko

Michihisa Magome

Takashi Matsui

Tomohisa Sano

Yoshitaka Suzumura

Yusuke Hasegawa

Shotaro Nomura

Tadashi Dojo

Akira Sakakibara

Eriko Yanase

Keisuke Tanaka

Katsuhisa Yamazaki

Atsuhiko Ohmori

Masami Fujimoto

Kozue Uratani

Syuhei Moribe

Takashige Kasuya

Yoshihiro Nakagawa

Daisuke Yoshiba

Masaaki Taya

Shuhei Moribe

Junko Nishiyama

Junko Hirata

The magnetic toner contains a magnetic toner particle having a binder resin and a magnetic body, and inorganic fine particles, wherein the average circularity of the magnetic toner is at least 0.955 and, when classifying the inorganic fine particles, in accordance with the fixing strength thereof to the magnetic toner particle and in the sequence of the weakness of the fixing strength, as first inorganic fine particles, second inorganic fine particles, and third inorganic fine particles, the content of the first inorganic fine particles, the ratio of the second inorganic fine particles to the first inorganic fine particles, and the coverage ratio X are in prescribed ranges.

Magnetic toner

A magnetic toner containing a magnetic toner particle having a binder resin and a magnetic body, and inorganic fine particles, wherein when the inorganic fine particles are classified as first inorganic fine particles, second inorganic fine particles, and third inorganic fine particles in accordance with fixing strength thereof to the magnetic toner particle and in the sequence of the weakness of the fixing strength, the content of the first inorganic fine particles, the ratio of the second inorganic fine particles to the first inorganic fine particles, and the coverage ratio X of coverage of the magnetic toner surface by the third inorganic fine particles are in prescribed ranges.

A magnetic toner including: magnetic toner particles containing a binder resin, a magnetic body, and a release agent; and inorganic fine particles present on the surface of the magnetic toner particles, wherein the inorganic fine particles present on the surface of the magnetic toner particles contain metal oxide fine particles, the metal oxide fine particles containing silica fine particles, and optionally containing titania fine particles and alumina fine particles, and a content of the silica fine particles being at least 85 mass % with respect to a total mass of the silica fine particles, the titania fine particles and the alumina fine particles, wherein the magnetic toner has a coverage ratio A of the magnetic toner particles' surface by the inorganic fine particles and a coverage ratio B of the magnetic toner particles' surface by the inorganic fine particles fixed to the magnetic toner particles' surface that reside in prescribed numerical value ranges; the binder resin contains a styrene resin; the release agent contains a monoester compound or a diester compound; and the softening temperature and softening point of the magnetic toner reside in prescribed temperature ranges.

A magnetic toner contains magnetic toner particles containing a binder resin, a release agent, and a magnetic body, and inorganic fine particles present on the surface of the magnetic toner particles, wherein a ratio of coverage of the magnetic toner particles' surface by the inorganic fine particles is in a prescribed range for the magnetic toner, the inorganic fine particles contain prescribed metal oxide fine particles, with at least 85 mass % of the metal oxide fine particles being silica fine particles, the coefficient of variation on the coverage ratio A is in a prescribed range, the binder resin contains a styrene resin, in a GPC measurement of a THF-soluble matter in the magnetic toner, a peak molecular weight (Mp) of a main peak is in a prescribed range, and a prescribed fatty acid ester compound is incorporated as a release agent.

Toner having silica fine particles

A magnetic toner is provided that exhibits an excellent dot reproducibility and developing performance after being allowed to stand in a high temperature and high humidity environment and an excellent low-temperature fixability. The magnetic toner has an inorganic fine powder and a magnetic toner particle containing a binder resin, a magnetic body, and a release agent, wherein in a stress relaxation measurement using a rotating plate rheometer, the magnetic toner exhibits a yield value A at 25&#xb0; C. of at least 3&#xd7;10(sec), and the magnetic toner that has been heated to 80&#xb0; C. and then cooled to 25&#xb0; C. exhibits a yield value B at 25&#xb0; C. of not more than 1&#xd7;10(sec).

Toner

A magnetic toner contains magnetic toner particles and silica fine particles. The magnetic toner has a thermal conductivity in the range of 0.230 to 0.270 W/(m&#xb7;K). Primary particles of the silica fine particles have a number-average particle diameter (D1) in the range of 5 to 20 nm. The coverage X1 of the magnetic toner surface by the silica fine particles ranges from 40% to 75% by area as determined using an X-ray photoelectron spectrometer (ESCA). The diffusion index (X1/X2) satisfies the following formula:Diffusion index&#x2267;&#x2212;0.0042&#xd7;1+0.62

A toner comprising toner particles which comprise a binder resin and a colorant, and also inorganic fine particles as external additives, wherein the inorganic fine particles are silica fine particles and a group 2 element titanate fine particles, the inorganic fine particles have specific particle diameters, the silica fine particles have a coverage ratio X1 on the surfaces of the toner particles, which is not less than 40.0 surface area % and not more than 75.0 surface area %, when the theoretical coverage ratio by the silica fine particles is X2, the diffusion index defined as 'diffusion index=X1/X2' satisfies the condition: diffusion index&#x2267;&#x2212;0.0042&#xd7;X1+0.62, and the external additives have an embedding ratio on the toner particles, which satisfies a specific range.

Disclosed is a toner which enables a stable image density to be obtained, regardless of the service environment, throughout use in durability tests, and which is able to suppress the occurrence of faulty cleaning. The toner contains both toner particles, which include a binder resin and a colorant, and also silica fine particles. The toner has an average circularity of at least 0.950, a static friction coefficient, with respect to a polycarbonate resin substrate, of at least 0.100 and not more than 0.200, and a coverage ratio X1 of the toner surface by the silica fine particles, as determined by X-ray photoelectron spectroscopy (ESCA), of at least 50.0 area %, and not more than 75.0 area %.

An image-forming method is provided which can provide stable image density irrespective of use environments and does not cause image defects such as fogging, tailing, or transfer voids, even when being applied to a developing sleeve with a reduced diameter. In the image-forming method, a latent image bearing member and a toner bearing member bearing a magnetic toner on its surface and having inside a unit for generating a magnetic field are placed with a predetermined interval, and an alternating field is applied between the latent image bearing member and the toner bearing member, and an electrostatic latent image borne by the latent image bearing member is developed with the magnetic toner. The toner bearing member has a specific diameter, and the magnetic toner has a specific circularity and a specific compressibility. The total energy of the toner measured with a powder flowability measuring apparatus satisfies a specific value.

Image-forming method, magnetic toner, and process unit

A toner with good low-temperature fixability even in light-pressure type fixing units, which causes no contamination of fixing films and provides images having stable image densities and excellent image quality after long-term use. The toner includes a toner particle containing a binder resin, a coloring agent, a release agents (a) and (b) The release agent (a) is a monofunctional or bifunctional ester wax; the release agent (b) is a hydrocarbon wax; a solubility of the release agent (a) into the binder resin is higher than that of the release agent (b). When tetrahydrofuran-soluble components of the toner are subjected to GPC, a proportion of components having a molecular weight of 500 or less is 2.5 area % or less. When the tetrahydrofuran-soluble components at 25&#xb0; C. are subjected to SEC-MALLS, a weight-average molecular weight Mw thereof is 5,000-100,000, and the Mw and the radius of gyration Rw thereof satisfy 5.0&#xd7;10&#x2266;Rw/Mw&#x2266;1.0&#xd7;10.

To provide a toner which can achieve both low-temperature fixing performance and dot reproducibility and further can obtain images on which any density non-uniformity has been kept from coming about, the toner has toner particles, each of the toner particles has a toner base particle containing a binder resin, a colorant and a release agent, and an inorganic fine powder; the toner having:

A magnetic toner has magnetic toner particles, each of the magnetic toner particles containing a binder resin and a magnetic material, and an inorganic fine powder. The magnetic material is prepared by treating the surface of magnetic iron oxide with a silane compound. When the magnetic iron oxide is dispersed in an aqueous solution of hydrochloric acid and dissolved until the dissolution proportion of the iron element reaches 5% by mass based on the total amount of the iron element contained in the magnetic iron oxide, the amount of silicon eluted by that point of time is 0.05% by mass or more and 0.50% by mass or less based on the magnetic iron oxide. The magnetic material has a moisture adsorption amount per unit area of 0.30 mg/mor less.

To solve a thin image density and sweeping occurring when a toner carrying member having a small diameter is used, provided is an image-forming method including: a charging step; an electrostatic latent image-forming step; a developing step; a transferring step; and a fixing step, in which a magnetic toner to be used in the method has a specific weight average particle diameter (D4); the magnetic toner has a specific intensity of magnetization in a specific magnetic field; and a surface free energy of a surface of the magnetic toner and a surface free energy of a surface of a toner carrying member to be used in the method satisfy specific relationships.

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Susono, Japan

Shuichi Hiroko