Canon Kabushiki Kaisha

Toshiyuki Ugai

Kenji Okado

Ryoichi Fujita

Tsuyoshi Takiguchi

Yasuhiro Ichikawa

Wakashi Iida

Manabu Ohno

Makoto Kanbayashi

Satoshi Yasuda

Kazunori Kato

Kazumi Yoshizaki

Hiroyuki Kobayashi

Tatsuya Nakamura

Akira Hashimoto

Satoshi Yoshida

Tsutomu Kukimoto

Yuko Sato

Shinya Yachi

Yasushi Katsuta

Shuichi Aita

Takaaki Kohtaki

Motoo Urawa

Keita Nozawa

Yoshinori Tsuji

Kenichi Nakayama

Hidekazu Fumita

Kiyoshi Mizoe

Fumihiro Arahira

Ichiro Ohsaki

Yoshifumi Hano

Yuki Karaki

To provide a process for producing toner particles in a good efficiency which have less residue of monomers and less other organic volatile components, the process has a polymerization step of polymerizing a polymerizable monomer composition containing at least a polymerizable monomer, in a vessel holding therein an aqueous medium, wherein a high-temperature saturated steam with a temperature higher than 100&deg; C. is introduced into the aqueous medium held in the vessel, at the latter half of polymerization or after the polymerization has been completed, to remove at least organic volatile components from toner particles having at least a binder resin and a colorant.

Process for producing toner particles, and toner

Toner, toner production process, and image-forming method

An electrophotographic apparatus includes an electrophotographic photosensitive member, and (i) a charger, (ii) an imagewise exposure device, (iii) a developing device and (iv) a transfer device, disposed in this order opposite to the photosensitive member. The charger includes a charging member including magnetic particles disposed in contact with the photosensitive member so as to charge the photosensitive member based on a voltage received thereby. The magnetic particles are surface-coated with a coupling agent having a linear alkyl group having a least 6 carbon atoms. The developing device also functions to recover residual toner remaining on the photosensitive member processing by the transfer device and the charger. Because of the coating with such a specific coupling agent, the charging magnetic particles can exhibit good triboelectric changeability for the transfer residual toner for a long period.

Electrophotographic apparatus, image forming method, and process cartridge for developing an image with toner containing an external additive

A process for producing a toner comprises the steps of: adjusting to 4.0 to 6.0 the pH of an aqueous medium containing a calcium phosphates obtained by mixing an aqueous phosphate solution with an aqueous calcium salt solution; dispersing in the aqueous medium a polymerizable monomer composition having at least a polymerizable monomer, a colorant, a polar polymer or polar copolymer having a carboxyl group, and a polymerization initiator to form particles of the polymerizable monomer composition; in the aqueous medium, polymerizing the polymerizable monomer contained in the particles to form toner particles; and adjusting the pH of the aqueous medium to 1.0 to 3.0 to dissolve the calcium phosphate, followed by separating the toner particles from the aqueous medium. The circularity of the toner obtained is not less than 0.970 and less than 1.000 as measured with a flow-type particle image analyzer (FIPA).

Process for producing toner

A non-magnetic toner for developing an electrostatic image has non-magnetic toner particles produced by polymerizing in an aqueous medium a polymerizable monomer composition containing at least a polymerizable monomer, a carbon black and an azo type iron compound. The carbon black has a DPB oil absorption of from 110 ml/100 g to 200 ml/100 g, a specific surface area of 100 m.sup.2 /g or below as measured by nitrogen adsorption, a volatile component of 2% or less and an average primary particle diameter of from 20 m.mu. to 60 m.mu., and the azo type iron compound is a compound represented by the following Formula (1). ##STR1##

Non-magnetic toner for developing electrostatic image, process for

A toner for developing an electrostatic image is composed of toner particles containing at least a binder resin, a colorant and a wax composition. The wax composition comprises an ester wax (1) having a long-chain alkyl group, and a wax (2). The wax (2) shows a maximum heat-absorption peak in a range of 40-130.degree. C. on temperature increase on a DSC (differential scanning calorimeter) curve, and gives a .sup.13 C-NMR (nuclear magnetic resonance) spectrum showing a total peak area S in a range of 0-50 ppm, a total peak area S1 in a range of 36-42 ppm, and a total peak area S2 in a range of 10-17 ppm, satisfying: 1.0.ltoreq.(S1/S).times.100.ltoreq.10, 1.5.ltoreq.(S2/S).times.100.ltoreq.15, and S.sub.1 &lt;S.sub.2. The toner particles contain A wt. parts of the ester wax (1), B wt. parts of the wax (2) and C wt. parts of the colorant, respectively per 100 wt. parts of the binder resin, satisfying: 3.ltoreq.A.ltoreq.30, 0.2.ltoreq.B.ltoreq.10, 4.ltoreq.A+B.ltoreq.40, 0.02.ltoreq.B/A.ltoreq.0.5, and 0.02.ltoreq.B/C.ltoreq.2.

Toner for developing electrostatic image and image forming method

An image forming method is disclosed in which a contact charging means is brought into contact with a latent image bearing member to electrostatically charge the latent image bearing member on which electrostatic latent images are formed and developed with a one component type or two component type developer to form toner images, using a developing assembly provided with a developing container and a developer carrying member. The one component developer is comprised of toner particles. The two component type developer is comprised of toner particles and a magnetic carrier. The toner particles of the one component type and two component type developers contains fine particles as an external additive. The latent image bearing member has a surface layer having a volume resistivity A of from 10.sup.8 to 10.sup.15 .OMEGA..multidot.cm; the contact charging means comprises an assembly for electrostatically charging the latent image bearing member by applying a voltage to a charging member having a volume resistivity B of from 10.sup.4 to 10.sup.9 .OMEGA..multidot.cm; the toner has, as an external additive, fine particles having a volume resistivity C of from 10.sup.7 to 10.sup.11 .OMEGA..multidot.cm; the magnetic carrier has a volume resistivity D1 of from 10.sup.9 to 10.sup.15 .OMEGA..multidot.cm; and the developer carrying member has a surface layer having a volume resistivity D2 of from 10.sup.9 to 10.sup.15 .OMEGA..multidot.cm. The resistivities A, B, C, D1 and D2 stasisfy the following conditions: B&lt;C&lt;A&lt;D1 or B&lt;C&lt;A&lt;D2.

Image forming method

A process for producing a toner for developing an electrostatic latent image. The process has the steps of dispersing in an aqueous medium having a pH of from 4.5 to 8.5 a polymerizable monomer composition containing at least a polymerizable vinyl monomer, a colorant, an organic metal compound, an aromatic carboxylic acid, a polyester resin having an acid value of from 5 mg.multidot.KOH/g to 50 mg.multidot.KOH/g, and a polymerization initiator, to form particles of the polymerizable monomer composition in the aqueous medium, and polymerizing the polymerizable vinyl monomer in the particles of the polymerizable monomer composition.

Process for producing toner for developing electrostatic latent images

A carrier for electrophotography has carrier particles. Each carrier particle has a carrier core and a silicone resin coat layer that covers the carrier core. The carrier particle has silicon atoms and carrier atoms on its surface in the ratio that satisfies the condition of Si/C=0.1 to 2.0 as the number of atoms present on the carrier particle surface as measured by X-ray photoelectron spectroscopy, and from 0.1% by number to 5% by number of metal atoms are present on the carrier particle surface. Additionally, there is a two-component developer for developing electrostatic images which consists of a toner and the carrier. An image forming method in which the two-component developer having the toner and the carrier is transported to a developing zone which is defined by a latent image carried on a latent image bearing member to develop the latent image. A voltage is applied to the developer to direct the toner from the latent image bearing member to a member carrying the developer. A second voltage directs the toner from the developer toward the latent image and a third voltage developer the latent image using the toner of the two-component developer.

Carrier for electrophotography, two-component type developer, and image

An electrophotographic black toner containing carbon black in a good dispersion state as well as a combined charge control agent system including a specific azo iron metal compound of formula (1) shown below and an oxycarboxylic acid metal compound is produced through polymerization in an aqueous system. The combined charge control agent system shows an effects of synergistically improving the chargeability of spherical polymerized toner particles. The azo iron metal compound improves the dispersion of the carbon black in the toner particles. ##STR1## wherein the denotations of R.sub.1 -R.sub.6, n, n' and A.sup..sym. are omitted.

Toner for developing electrostatic images and process for production

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

An image forming method is conducted by forming a toner image on a latent image bearing member containing an organic photoconductive material. The latent image bearing member includes a photosensitive layer containing an organic photoconductive material and a protective layer which contains fluorine-containing resin particles in an amount from 5% by weight to 40% by weight. The toner contains toner particles and external additives. The external additives include titanium oxide particles having a weight average particle diameter from 0.01 .mu.m to 0.2 .mu.m having been subjected to hydrophobic treatment, organic resin particles having a weight average particle diameter from 0.02 .mu.m to 0.5 .mu.m, and inorganic compound particles having a weight average particle diameter from 0.5 .mu.m to 2.5 m. The inorganic compound particles may be specific titanates, oxides or carbonate. The external additives are added in an amount satisfying the relationship:

Image forming method employing toner with external additive

An image-forming method is comprised of delivering a transfer-receiving medium to a first image-forming unit, forming a first toner image by a first image-forming means of the first image-forming unit, transferring the first toner image onto the transfer-receiving medium at a first transfer section of the first image-forming unit with a first transfer bias applied, and delivering the transfer-receiving medium to a second image-forming unit. Forming a second toner image by a second image-forming means of the second image-forming unit, transferring the second toner image onto the transfer-receiving medium carrying the first toner image at a second transfer section of the second image-forming unit with a second transfer bias applied, fixing the first toner image and the second toner image transferred on the transfer-receiving medium by a fixing means. The length of the transfer-receiving medium in the direction in which the transfer-receiving medium is conveyed is larger than the spacing between the first transfer section and the second transfer section. The intensity of the second transfer bias is different from the intensity of the first transfer bias. A first toner for forming the first toner image and a second toner for forming the second toner image both have shape factors of SF-1 ranging from 100 to 180 and SF-2 ranging from 100 to 140.

Image-forming method and image-forming apparatus

A carrier for electrophotography has carrier particles. The carrier has a 50% average particle diameter (D.sub.50) of from 15 .mu.m to 45 .mu.m and contains from 1% to 20% of carrier particles with a size smaller than 22 .mu.m, not more than 3% of carrier particles with a size smaller than 16 .mu.m, from 2% to 15% of carrier particles with a size of 62 .mu.m or larger, and not more than 2% of carrier particles with a size of 88 .mu.m or larger. The carrier has a specific surface area S.sub.1 as measured by an air-permeability method and a specific surface area S.sub.2 as calculated by the following expression:

The present invention provides a toner for developing an electrostatic image, comprising toner particles and external additives, wherein;

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Tokyo, Japan

Toshiyuki Ugai