Canon Kabushiki Kaisha

Tsutomu Kukimoto

Tsuyoshi Takiguchi

Hiroshi Yusa

Koichi Tomiyama

Eiichi Imai

Shuichi Aita

Akira Hashimoto

Manabu Ohno

Satoshi Yoshida

Motoo Urawa

Yoshifumi Hano

Keiji Komoto

Hiroyuki Suematsu

Hisayuki Ochi

Tetsuhito Kuwashima

Satoshi Handa

Keita Nozawa

Tetsuya Kuribayashi

Tatsuhiko Chiba

Masayoshi Kato

Yasukazu Ayaki

Kiyoko Tsuchiya

Michihisa Magome

Kenji Okado

Masanori Ito

Toshiyuki Yoshihara

Kiyoshi Mizoe

Fumihiro Arahira

Yuki Karaki

Yuki Nishio

Tatsuya Nakamura

Takashige Kasuya

Hirohide Tanikawa

Katsuhiko Tanaka

Masaki Ojima

Katsuhiro Sakaizawa

Akio Maruyama

Masayoshi Shimamura

Masaki Uchiyama

Satoshi Matsunaga

Yasuhide Goseki

Yasuo Mitsuhashi

Keiji Okano

Kiichiro Sakashita

Kazuyoshi Hagiwara

Seiichi Takagi

Toshiyuki Ugai

Osamu Tamura

Naoto Kitamori

Yuji Ishihara

Yukou Sato

Tsuyoshi Takuguchi

Kohichi Tomiyama

A dry toner has toner particles containing at least a binder resin, a colorant and a wax component and an external additive. The binder resin contains a component derived from a monomer selected from butadiene, isoprene and chloroprene. The toner has a main Tg from 40&deg; C. to 70&deg; C. When specific surface area measured by the BET method in an environment of 23&deg; C. atmospheric temperature and 65% relative humidity is represented by A (m /g) and specific surface area measured by the BET method in an environment of 50&deg; C. atmospheric temperature and 3% relative humidity is represented by B (m /g), the toner satisfies the following relationship: 0.8&lE;A&lE;4.0, 0.80&lE;(B/A)&lE;1.05. The toner has a circle-corresponding number-average particle diameter D1 from 2 to 10 &mgr;m, an average circularity from 0.950 to 0.995 and a circularity standard deviation less than 0.040. The toner has a main-peak molecular weight from 2,000 to 100,000 and contains a THF-insoluble matter from 5 to 60% by weight.

Dry toner, dry toner production process, and image forming method

A toner is comprised of a binder resin, a colorant and a wax. The binder resin has a polycarbonate resin in an amount of from 0.1% by weight to 50.0% by weight and a resin other than the polycarbonate resin in an amount of from 50.0% by weight to 99.9% by weight, based on the weight of the binder resin. In molecular weight distribution as measured by gel permeation chromatography of tetrahydrofuran-soluble matter, the toner contains in an amount of 15.0% by weight or less based on the weight of the toner a component which has in its structure a repeating unit of the polycarbonate resin and is contained in components having a molecular weight of 1,000 or less.

Toner and image forming method

A magnetic toner comprising magnetic toner particles containing at least a binder resin, a magnetic material containing a magnetic iron oxide, and a release agent. The magnetic toner has a weight-average particle diameter of from 3 &mgr;m to 10 &mgr;m, a magnetization intensity (saturation magnetization) of from 10 Am /kg to 50 Am /kg (emu/g) under application of a magnetic field of 79.6 kA/m (1,000 oersteds), an average circularity of 0.970 or more, a ratio of weight-average particle diameter to number-average particle diameter, of 1.40 or less, iron and an iron compound which stand liberated from the magnetic toner particles at a liberation percentage of from 0.05% to 3.00%, and a resin component having a tetrahydrofuran-insoluble matter in an amount of from 3% by weight to 60% by weight. Also disclosed is an image-forming method making use of the magnetic toner.

Magnetic toner and image-forming method making use of the same

Magnetic particles for charging means, and electrophotographic apparatus, process cartridge and image forming method including same

A magnetic toner includes: magnetic toner particles each comprising at least a binder resin and magnetic toner, and inorganic fine powder. The magnetic toner has an average circularity of at least 0.970, and a magnetization of 10-50 Am /kg at a magnetic field of 79.6 kA/m. The magnetic powder comprises at least magnetic iron oxide. The magnetic toner particles retain carbon in an amount of A and iron in an amount of B at surfaces thereof as measured by X-ray photoelectron spectroscopy, satisfying: B/A<0.001. The binder resin comprises a resin formed by polymerization of a monomer comprising at least styrene monomer. The magnetic toner has a residual styrene monomer content of less than 300 ppm, and contains at least 50% by number of toner particles satisfying a relationship of: D/C&lE;0.02, wherein C represents a volume-average particle size of the magnetic toner, and D represents a minimum distance between the surface of a magnetic toner particle and magnetic powder particles contained in the magnetic toner particle. Owing to the above features, the magnetic toner can exhibit good electrohotographic performances, including excellent chargeability and little transfer-residual toner, even in a cleanerless-mode image forming system.

Magnetic toner, process for production thereof, and image forming method, apparatus and process cartridge using the toner

A toner is formed of toner particles each comprising a binder resin and iron oxide particles dispersed therein. The toner particles are characterized by uniform but non-surface-exposed dispersion of the iron oxide particles within the toner particles as represented by (i) a carbon content (A) and an iron content (B) giving a ratio B/A<0.001 at surfaces of the toner particles as measured by X-ray photoelectron spectroscopy, (ii) an average circularity of at least 0.970, and (iii) at least 50% by number of toner particles satisfying D/C&lE;0.02, wherein C denotes a projection area-equivalent circular diameter of each toner particle and D denotes a minimum distance of iron oxide particles from a surface of the toner particle, based on a sectional view of the toner particle as observed through a transmission electron microscope (TEM).

A toner for developing an electrostatic image has toner particles containing at least a binder resin, a colorant, and a wax. The wax contains an ester compound represented by specific formula, or a mixture thereof at a content ranging from 50 to 100% by weight based on the weight of the wax.

Electrostatic image-developing toner and image-forming method

An image forming method includes charging an image carrier for carrying an electrostatic latent image; forming an electrostatic latent image on the charged image carrier; developing the electrostatic latent image with a toner by contacting a toner layer on a surface of a toner carrier with a surface of the image carrier to form a toner image thereon; copying the toner image formed on the surface of the image carrier onto a copy medium; wherein the toner has toner particles containing at least a bonding resin, carbon black and an azo-based iron compound and inorganic fine powder; the carbon black having an average primary particles size within a range of from 25 to 80 nm; and the azo-based iron compound having a specific structure.

Image forming method featuring a residual charge control property

A toner for developing electrostatic images is formed from toner particles containing at least a binder resin, a colorant, and a wax. The binder resin comprises a vinyl polymer component and a polyester component. The binder resin contains 40-99 wt. % of a component A, 0-20 wt. % of a component B, and 0-60 wt. % of a component C, the components B and C providing totally 1-60 wt. % of the binder resin. The component A comprises low- and medium-molecular weight components having molecular weights of below 10.sup.6, and the component B comprises high-molecular weight components having molecular weights of at least 106, respectively, based on a chromatogram obtained by gel permeation chromatography of a tetrahydrofuran (THF)-soluble component of the binder resin, and the component C is a THF-insoluble component of the binder resin. The GPC chromatogram of the THF-soluble component of the binder resin exhibits a main peak in a molecular weight region of 3.times.10.sup.3 -5.times.10.sup.4. The toner particles have a shape factor SF-1 of 100-160 and a shape factor SF-2 of 100-140.

Toner for developing electrostatic images and image forming method

A charging apparatus which comprises an electrophotographic photosensitive member and a charging member which comprises magnetic particles and placed in contact with the electrophotographic photosensitive member to charge the electrophotographic photosensitive member upon application of a voltage, wherein each magnetic particle has a surface layer containing a polyolefin resin of which weight average molecular weight is 10,000 or more, and has a volume resistivity of 1.times.10.sup.4 to 1.times.10.sup.11 .OMEGA.cm.

Charging apparatus and electrophotographic apparatus

An electrophotographic image forming method according to (I) a so-called simultaneous development and cleaning scheme or cleaner-less scheme is effectively operated by using a specific non-magnetic toner. (II) The non-magnetic toner comprises non-magnetic toner particles having a shape factor SF-1 of 120-160, a shape factor SF-2 of 115-140 and a weight-average particle size of 4-9 .mu.m. (III) The non-magnetic toner further includes inorganic fine particles (a) having a number-average primary particle size of at most 50 nm and spherical fine particles (b) having a number-average primary particle size of 50-1000 nm and a surface area-based sphericity .psi. of 0.91-1.00, respectively externally added to the non-magnetic toner particles.

Image forming method utilizing toner having inorganic particles and

An electrophotographic apparatus is constituted by an electrophotographic photosensitive member, and a charger, imagewise exposing light and a developer disposed in this order opposite to the photosensitive member. The photosensitive member has a surface layer which is a charge-injection layer. The charger includes a charging member formed of magnetic particles and disposed contactable to the photosensitive member so as to charge the photosensitive member to at least 80% of a DC voltage supplied to the charging member. The magnetic particles have a volume resistivity in the range of 1.times.10.sup.4 -1.times.10.sup.9 ohm.cm, and the magnetic particles have a surface layer having a volume resistivity of at most 1.times.10.sup.9 ohm.cm.

Electrophotographic apparatus using photoconductive member chargeable

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 image forming method has a developing step of developing an electrostatic latent image by the use of a developer to form a toner image on an electrostatic latent image bearing member, a primary transfer step of transferring the toner image onto an intermediate transfer member to which a voltage is applied, and a secondary transfer step of transferring onto a transfer medium the toner image held on the intermediate transfer member, while a transfer means to which a voltage is applied is pressed against the transfer medium. The developer has a toner. The toner is a black toner having at least i) black toner particles formed of a binder resin with a colorant dispersed therein and ii) an inorganic fine powder. The black toner has the value of shape factor SF-1 of 110&lt;SF-1.ltoreq.180, the value of shape factor SF-2 of 110&lt;SF-2.ltoreq.140, and the value of ratio B/A of 1.0 or less which is the ratio of a value B obtained by subtracting 100 from the value of SF-2 to a value A obtained by subtracting 100 from the value of SF-1.

Image forming method and apparatus using a particular toner

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Yokohama, Japan

Tsutomu Kukimoto