Canon Kabushiki Kaisha

Nobuyuki Okubo

Tsutomu Onuma

Shunji Suzuki

Manabu Ohno

Kaori Hiratsuka

Hirohide Tanikawa

Koji Nishikawa

Akihiko Nakazawa

Shuhei Moribe

Tsuneo Nakanishi

Koichi Tomiyama

Hiroyuki Suematsu

Yoshihiro Ogawa

Katsuhisa Yamazaki

Shinichiro Abe

Masayoshi Kato

Takashige Kasuya

Yushi Mikuriya

Makoto Unno

Takaaki Kohtaki

Tadashi Doujo

Osamu Tamura

Hideto Iida

Takakuni Kobori

Keita Nozawa

Yoshinori Tsuji

Satoshi Mitsumura

Masaichiro Katada

Yukari Ishibashi

Masao Takano

A process for producing a toner by subjecting a polymer and a resin component containing a cross-linkable polymer capable of cross-linkingly reacting with the polymer, to cross-linking reaction in the presence of a first wax to form a wax-containing cross-linked polymer composition; mixing the wax-containing cross-linked polymer composition with at least a colorant and a second wax, followed by melt-kneading to form a toner composition; and pulverizing the toner composition to produce toner particles. Also disclosed is a toner produced by this process. The toner thus obtained is a toner whose fixing performance and anti-offset properties are well balanced and also which makes it possible to afford images having less fog and high quality, over a long period of time in environments of from low temperature and low humidity to high temperature and high humidity, and is highly durable without causing any contamination of members with which the toner comes into contact.

Process for producing toner, and toner

A toner is disclosed including toner particles containing a binder resin and a colorant. The binder resin contains a vinyl resin. In the high-temperature GPC-RALLS-viscometer analysis of the o-dichlorobenzene-soluble matter of the toner, a weight-average molecular weigh of absolute molecular weights measured with a viscosity detector is in a specific range. In the o-dichlorobenzene-soluble matter, a component with the absolute molecular weight of 10,000 or less and a component with the absolute molecular weight of 1,000,000 or more are present in specific proportions, respectively. The intrinsic viscosity of the toner is in a specific range.

Toner

A toner is composed of toner particles including toner base particles containing at least a binder resin and a colorant, and inorganic fine particles. The toner base particles having a specific circle-equivalent diameter as measured with a flow type particle image analyzer have a specific average circularity. The toner base particles have a specific surface roughness as measured with a scanning probe microscope. The binder resin contains at least a vinyl resin having as partial structure a linkage formed by the reaction of a carboxyl group with an epoxy group.

In a toner comprising toner particles which comprise toner base particles containing at least a binder resin and a magnetic material, and inorganic fine particles, the toner base particles have been obtained through a pulverization step; and, the toner base particles having a circle-equivalent diameter of from 3 &#x3bc;m or more to 400 &#x3bc;m or less as measured with a flow type particle image analyzer have an average circularity of from 0.935 or more to less than 0.970; and the toner base particles have an average surface roughness of from 5.0 nm or more to less than 35.0 nm as measured with a scanning probe microscope. The toner can enjoy less toner consumption per sheet of images, can achieve a long lifetime in a smaller quantity of toner, and has superior developing performance in any environment.

A process cartridge which is detachably mountable to a main body of an image-forming apparatus has a photosensitive member, a magnetic toner-holding section provided with a magnetic toner-carrying member which transports the toner to a developing zone, and a residual magnetic toner detector capable of detecting residual toner by a change in electrostatic capacity which is caused between electrodes provided inside the magnetic toner-holding section. The magnetic toner contains at least a binder resin and a colorant, having a weight-average particle diameter of from 6.5 &mgr;m to 15.0 &mgr;m, and having a Carr's floodability index of more than 80.

Process cartridge

In a toner production process having at least a kneading step, a pulverization step using a mechanical grinding machine, and a classification step, the grinding means comprises a mechanical grinding machine having at least a rotor which is a rotator attached to the center rotating shaft and a stator which is provided around the rotor, keeping a constant gap between the stator and the rotor surface, the grinding machine being so constructed that a circular space formed by keeping the gap stands airtight, and the surface of at least one of the rotor and the stator is coated by the plating of a chromium alloy containing at least chromium carbide.

Toner production process

A magnetic toner is formed of magnetic toner particles each comprising at least a binder resin and a magnetic iron oxide. The magnetic toner is provided with improved developing performances by realizing an appropriate surface-exposure state of the magnetic iron oxide, which is represented by a wettability characteristic in methanol/water mixture liquids of the magnetic toner such that it shows a transmittance of 80% for light at a wavelength of 780 nm at a methanol concentration in a range of 65-75% and a transmittance of 20% at a methanol concentration in a range of 66-76%.

Magnetic toner and process cartridge

A dry magnetic toner is formed of magnetic toner particles comprising a binder resin and magnetic iron oxide particles. The magnetic toner is provided with excellent developing performances and transferability by controlling the presence of isolated iron-containing particles and containing a high percentage of spherical particles, the amount of which is controlled relative to the weight-average particle size of the magnetic toner and a content of particles of 3 &mgr;m or below in the magnetic toner.

Dry toner, image forming method and process cartridge

A toner is principally constituted by a binder resin, a colorant and a hydrocarbon wax. The hydrocarbon wax has a hydroxyl value (Hv) of 5-150 mgKOH/g and an ester value (Ev) of 1-50 mgKOH/g satisfying Hv>Ev. Further, the toner has a tetrahydrofuran-soluble content providing a gel-permeation chromatogram showing at least one peak in a molecular weight region of 3&times;10 to 5&times;10 and at least one peak or shoulder in a molecular weight region of 1&times;10 to 1&times;10 .

Toner having hydrocarbon wax with specific ester value and hydroxyl value

A toner having a stable chargeability in various environments, a stable fixability over a wide temperature range and a resistance to sticking on an image-bearing member, is formed of a binder resin, a colorant and an azo iron compound as a charge control agent. The azo iron compound is formed from a monoazo compound having at least one alkyl group and two hydroxyl groups capable of bonding with an iron atom. The toner has a tetrahydrofuran-soluble content providing a gel-permeation chromatogram showing at least one peak in a molecular weight region of 3&times;10 to 5&times;10 and at least one peak or shoulder in a molecular weight region of above 5&times;10 and at most 1&times;10 .

Toner containing azo iron compound

Toner for developing electrostatic image, image forming method and process cartridge

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.

Toner for developing electrostatic image, image forming method and

A magnetic toner includes magnetic toner particles containing at least a binder resin and a magnetic iron oxide. The magnetic iron oxide contains 0.2 to 4.0% by weight of at least one metal element selected from the group consisting of Mn, Zn, Ni, Cu, Co, Cr, Cd, Al, Sn and Mg, and 0.2 to 0.8% by weight of silicon element on the basis of an iron element; the ratio (B.sub.si /A.sub.Si).times.100 of the content B.sub.Si of the silicon element present in the magnetic iron oxide up to an iron element solubility of 20% by weight to the total content A.sub.Si of the silicon element present in the magnetic iron oxide is 45 to 85%; the ratio (C.sub.si /A.sub.Si).times.100 of the content C.sub.Si of the silicon element present in the magnetic iron oxide up to an iron element solubility of 10% by weight to the total content A.sub.Si is 35 to 70%; and the magnetic toner has a weight average particle diameter of 3.5 to 10.0 .mu.m, and contains 0 to 30% by volume of magnetic toner particles having a volume particle diameter of 12.7 .mu.m or more determined from a volume distribution.

Magnetic toner, image forming method and process cartridge

A toner for developing an electrostatic image is constituted by a composition containing a binder resin component and a coloring agent, wherein the binder resin component contains a low-molecular weight component having a molecular weight of at most 5.times.10.sup.4 and a branching index g' of below 1. The low-molecular weight polymer component is preferably obtained by polymerizing a second monomer in mixture with a prepolymer in the presence of a polymerization initiator comprising a peroxide having a functional group of: ##STR1## and mixed with a high-molecular weight polymer component obtained by polymerization in the presence of a poly-functional polymerization initiator, and a low-molecular weight wax. The resultant toner is characterized by a good balance between the fixability and anti-offset characteristic.

Growing community of inventors

Yokohama, Japan

Nobuyuki Okubo