Canon Kabushiki Kaisha

Masuo Yamazaki

Toru Matsumoto

Katsutoshi Wakamiya

Toshiaki Nakahara

Yasuhide Goseki

Ichiro Ohsaki

Hisayuki Ushiyama

Katsuhiko Nishimura

Yusuke Karami

Tatsuya Nakamura

Takashige Kasuya

Kimio Nakahata

Yasutaka Akashi

Satoshi Matsunaga

Hiroaki Kawakami

Masahide Hirai

Hiromichi Yamada

Takashi Shibuya

Yasuo Yoda

Hisayuki Ochi

Masami Takeda

Shinji Doi

Tohru Kosaka

Toshiyuki Koshio

Junichi Kurimoto

Tohru Saitou

Kiyoko Maeda

Koichi Tanigawa

Tatsuhiko Chiba

Hiroshi Yusa

Hitoshi Kanda

Takaaki Kohtaki

Masashi Kiuchi

Atsuko Kobayashi

Tohru Matsumoto

An image forming apparatus including a rotatable developing member having a plurality of developing devices for developing an image bearing member at a first developing station, and a second single developing device arranged upstream of the rotatable developing member for developing the image bearing member exclusively at a second developing station different from the first developing station. The second developing device has a cover portion covering the rotatable developing member, and a portion of the cover portion is disposed at a position spaced apart from a rotation axis of the rotatable developing member by a predetermined length in a horizontal direction away from the image bearing member. The rotatable developing member rotates in an opposite direction with respect to the direction of rotation of the image bearing member to prevent toner from scattering toward the optical system.

Image forming apparatus having a rotatable first developing member, and

A heat fixable toner comprises a binder resin and a release agent. The binder resin comprises a polyester resin, and the release agent comprises a graft-modified polyolefin. A recording medium containing a toner image of said heat fixable toner is heat-fixed by contacting the recording medium with a heater element through a film interposed therebetween. After the heat-fixing step, the film is peeled from the fixed toner image while the film surface temperature is higher than the endothermic peak temperature of the toner.

Heat fixing method employing peelable film between heater and recording

A developer is carried on a developer-carrying member and conveyed to a developing region to be used for developing an electrostatic latent image formed on an electrostatic latent image-bearing member. The developer includes a non-magnetic toner, and the toner includes toner particles containing 5-30 wt. % of a low-softening compound and having a shape factor SF-1 of 100-130. The developer-carrying member has a developer-carrying surface satisfying the conditions of:

Image developing method using specific type toner and developing sleeve

An image forming method, comprising the steps of forming an electrostatic image on a electrostatic image-bearing member, developing the electrostatic image with toner particles having a first shape factor (SF-1) of 100-150 and containing a low-softening point substance to form a toner image on the electrostatic image-bearing member, transferring the toner image on the electrostatic image-bearing member to an intermediate transfer member which has been voltage-applied, transferring the toner image on the intermediate transfer member to a transfer-receiving material by a transfer means which has been voltage-applied, and heat-fixing the toner image on the transfer-receiving material. The toner particles may preferably have a second shape factor (SF-2) of 100-140. The total of SF-1 and SF-2 may preferably at most 275, particularly at most 240, for improving transfer efficiency of the toner particles. The low-softening point substance may preferably be an ester wax having a long-chain (e.g., .gtoreq.C.sub.10) alkyl group. The image forming method is effective in providing a high-quality (full-color) toner image with high transfer efficiency and free from toner sticking.

Image forming method

This invention relates to a color image forming apparatus for forming a color image with dry developer, capable of preventing deterioration of image quality, resulting from contamination of optical components by the non-magnetic developer scattered from the developing unit. For this purpose there are provided, along the moving direction of an image bearing member effecting endless movement, charging means, optical means, first developing means utilizing developer containing a magnetic component, second developing means utilizing non-magnetic developer of a color different from that of the developer of the first developing means, and transfer means maintained in contact with or close to the image bearing member for transferring a developed image from the image bearing member to a recording material such as paper. A space containing the second developing means is enclosed by the shape of the first developing means, transfer means and image bearing member.

Image forming apparatus for forming color image with dry developer

A heat fixable toner comprises a binder resin and a release agent. The binder resin comprises a polyester resin, and the release agent comprises a graft-modified polyolefin.

Fixable toner with a modified bisphenolic polyester resin

A microcapsule toner is produced through the steps of: passing resinous base particles (A1) comprising at least a binder resin and modifier particles (B) having a particle size ratio of 0.2 or less with respect to the base particles (A1) through an impact zone having a minimum clearance of 0.5-5 mm between a rotating member and a fixed member or between at least two rotating members at an ambient temperature of 10.degree.-90.degree. C. thereby to fix the modifier particles (B) onto the surfaces of the base particles (A1) under the action of a mechanical impact force to form particles (A2), the modifier particles (B) being particles selected from the group consisting of charge-controlling particles releasing particles, colored particles, charge-suppressing particles and abrasive particles; and passing the particles (A2) and shell-forming resin particles (C) having a particle size ratio of 0.2 or less with respect to the particles (A2) through an impact zone having a minimum clearance of 0.5-5 mm between a rotating member and a fixed member or between at least two rotating members at an ambient temperature of 10.degree.-90.degree. C. thereby to fix the shell-forming resin particles onto the surfaces of the particles (A2) under the action of a mechanical impact force to form a shell, thus obtaining a microcapsule toner.

Process for producing microcapsule toner

A method of heat fixing a toner image comprises heat fixing a toner image on a recording material with a heating member fixed and supported and a pressurizing member which is opposed to, in pressure contact with said heating member and adapted to bring said recording material into pressure contact with said heat member through a film, wherein said toner image is formed of a toner, said toner comprises a binder resin and a colorant, said binder resin has a melt viscosity of 0.1 to 10.sup.7 centipoise at 140.degree. C. and the gradient (.theta.) of the straight line represented by the following formula comprising the reciprocal number (1/T) of the absolute temperature when the toner is melted by heating with the heating member and the logarithm (log .eta.) of the melt viscosity of the binder resin at this time is 10.sup.2 to 3.times.10.sup.3 :

Heat fixing method

An encapsulated toner for electrophotography is produced through a process, comprising: preparing a solution of a shell material resin set to an acidic (or basic) pH region; dispersing solid core particles in the solution to form a dispersion; changing the pH of the dispersion to a pH region, which is preferably a basic (or acidic) pH region, where the shell material resin is precipitated from the dispersion; and coating the solid core particles with the precipitated shell material resin. The shell material is preferably a proton-attracting basic (or dissociative acidic) vinyl-type copolymer and is dissolved in a pH-adjusted aqueous medium comprising water and a polar solvent, such as a lower alcohol. Thus, an encapsulated toner with excellent triboelectric chargeability and environmental characteristic is prepared without coalescence of capsules or formation of free shells.

Process for producing encapsulated toner

A mixture of a colorant, and a binder compound having an aliphatic hydrocarbon long chain and having a relatively low melt viscosity, is kneaded in a molten state in the presence of solid media such as balls or beads to form a uniform mixture in which the colorant particles or aggregates have been disintegrated to a size of 5 .mu. or below. Solid particles which may be used as a toner are formed from the uniform mixture and may be encapsulated, as desired, to provide a capsule toner.

Process for preparing toner or capsule toner for use in

An encapsulated toner is provided by coating core particles with an outer shell. The outer shell comprises, as predominant components thereof, vinyl polymers A and B of different molecular weights. More specifically, the ratio of the number-average molecular weight of the vinyl polymer A (Mn.sub.A) to that of the vinyl polymer B (Mn.sub.B) is in the range of 2 to 15. The vinyl polymers A and B respectively have a ratio of weight-average molecular weight to number-average molecular weight of 5 or less. Because of these specific molecular weight characteristics of the shell-constituting polymers, the durability and triboelectric charging characteristics of the encapsulated toner are improved. These effects are enhanced particularly when inorganic fine particles are attached to embedded in the surface or surface layer of the core particles.

Encapsulated toner having shell with first vinyl polymer with Mn of

An encapsulated toner for development of electrical latent images comprises a core particle containing a colorant and a soft solid material, inorganic fine particles attached to the vicinity of the surface of the core particle, and a shell coating the core particle and the inorganic fine particles. The inorganic fine particles function to, e.g., reinforce the encapsulated toner with a thin shell and may be attached to the core particles through dry-mixing. The core particles with the attached inorganic particles may be coated with a shell resin through phase separation.

Encapsulated electrostatic toner with locally attached non-magnetic

A developing method, which comprises arranging a latent image-bearing member which bears a latent image on the surface and a toner-carrying member which carries an insulating non-magnetic toner at the developing section with a certain gap provided therebetween, coating the toner-carrying member with the insulating non-magnetic toner, conveying the resultant coated layer to the developing section while regulating the thickness thinner than said gap and developing the latent image on the latent image-bearing member under the application of an alternate electric field on the toner. Since the toner has a form of a microcapsule comprising a soft core material and a hard shell material and also contains a colorant in addition to the core material, adequate discharging can be effected during triboelectric charging to give an image with a constant density through stably charged state.

Developing method and insulating nonmagnetic toner therefor

A pressure-fixable toner comprising a combination of a compound A having a hydrocarbon chain and a compound B having an amino group in addition to a hydrocarbon chain is excellent in dispersibility of colorant, pressure fixing characteristic and developing characteristic. Further, an encapsulated pressure-fixable toner comprising a core of the pressure-fixable toner particles and a shell encapsulating the core is also excellent in these properties.

Pressure-fixable toner comprising combination of a compound having

A core material comprising a binder mixture of a long chain organic compound and an ester of a higher alcohol and a higher carboxylic acid is encapsulated with a thin shell material to give an encapsulated toner. The encapsulated toner has a uniform structure and a narrow particle size distribution and is excellent in developing and fixation characteristics, when used in electrophotography, etc.

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Kawasaki, Japan

Masuo Yamazaki