Canon Kabushiki Kaisha

Manami Haraguchi

Takeshi Yamamoto

Hiroyuki Fujikawa

Kenta Kubo

Atsushi Nakamoto

Makoto Fukatsu

Yoshinobu Baba

Takayuki Itakura

Kunihiko Nakamura

Nozomu Komatsu

Tomoaki Miyazawa

Juun Horie

Koh Ishigami

Kazunari Hagiwara

Tatsuaki Orihara

Shuhei Tokiwa

Naoki Okamoto

Yojiro Hotta

Kazuhisa Kemmochi

Tetsuya Ida

Masayoshi Kato

Kazuo Terauchi

Noriyoshi Umeda

Hirokazu Usami

Katsuhiro Sakaizawa

Takahiro Kawamoto

Yasunori Chigono

Kazuyuki Sato

Tomohito Ishida

Kei Inoue

Ryo Inoue

Katsuhiro Watanabe

Shuji Moriya

Yasuhiro Horiguchi

Yasuyuki Matsumoto

Jumpei Shirono

Shintaro Ishida

Emi Hagiwara

Kazuo Uchida

A toner according to the present disclosure maintains high transfer efficiency for the long term and obtains images which are not affected by toner base particles easily, which exhibit excellent charge stability, and which exhibit less fogging, wherein the toner is obtained by making inorganic fine particles and charge control particles, which satisfy specific conditions, present on the surfaces of toner base particles so as to satisfy a specific coverage relationship.

Toner

There is provided a toner including toner base particles and an external additive in which the external additive is prevented from being buried in the base particles. The toner can maintain a high transfer efficiency over an extended period of use. The toner includes: (1) toner base particles containing a cycloolefin copolymer and a polyethylene; or (2) toner base particles whose surfaces contain a resin having an elastic deformation rate of 70% or more and a melting temperature of 125.0&#xb0; C. or less.

Provided is a toner, including a toner particle having a core particle containing a binder resin and a colorant. The toner particle has a protrusion on a surface thereof, and the protrusion contains an olefin-based polymer having a cyclic olefin structure. When an average radius of curvature of the protrusion, an average particle diameter of the core particle, a projected area of the toner particle, and a projected area of the protrusion that are calculated from a planar projected image of an image of the toner particle photographed with a scanning electron microscope are represented by Rs (&#x3bc;m), Rc (&#x3bc;m), S, and S1, respectively, the average radius of curvature Rs of the protrusion is 0.004Rc &#x3bc;m or more and 0.100Rc &#x3bc;m or less, and an average of a surface coverage '100&#xd7;S1/S' % is 5% or more and 90% or less.

Toner and method of producing the toner

In an image forming apparatus having a photosensitive drum that carries a toner image, a developing roller is provided to be capable of rotating while carrying toner and supplies the toner to the photosensitive drum in order to develop a latent image, and a voltage applying device applies a voltage to the developing roller. The developing roller includes a conductive base layer and a surface layer covering the base layer, and a surface charge density of the developing roller is equal to or smaller than a surface charge density of the toner.

Image forming apparatus

A developing roller that is capable of carrying toner on a surface thereof, and that supplies the toner carried on the surface to a surface of a photosensitive drum when a voltage is applied thereto, includes: an elastic layer; and a surface layer that covers the elastic layer and contains aluminum oxide, wherein the aluminum oxide of the surface layer contains tetracoordinated aluminum atoms and hexacoordinated aluminum atoms existing in a higher proportion than the tetracoordinated aluminum atoms.

Developer carrying member, developing assembly, process cartridge, and image forming apparatus

In an image forming apparatus having a photosensitive drum capable of carrying a toner image, a developing roller that is provided to be capable of rotating while carrying toner, and that supplies the toner to the photosensitive drum by contacting the photosensitive drum, a regulating blade that regulates a layer thickness of the toner carried on the developing roller, and a voltage applying device for applying a voltage to the developing roller and the regulating blade. The developing roller includes a conductive base layer and a surface layer covering the base layer, and a surface charge density of the developing roller is equal to or smaller than a surface charge density of the toner.

An image forming apparatus includes a photosensitive member, a first developer carrying member for carrying a developer comprising toner and a carrier for developing an electrostatic image formed on the photosensitive member, and a second developer carrying member for carrying the developer received from the first developer carrying. The second developer carrying member is disposed downstream of the first developer carrying member with respect to a rotational direction of the photosensitive member. In addition, a voltage source applies a developing bias voltage to the first developer carrying member and second developer carrying member, and a driving device rotates the first developer carrying member at a peripheral speed higher than that of the photosensitive member and rotates the second developer carrying member at a peripheral speed which is higher than that of the photosensitive member and which is lower than that of the first developer carrying member.

A toner containing toner base particles and an external additive, wherein regions with different tribocharging polarities with respect to a magnetic carrier are present in a domain-matrix structure on the surface of the toner base particles. The island region B has a predetermined height, the external additive has a reverse polarity to the region B in terms of tribocharging polarity to the magnetic carrier, the external additive contains a first external additive having a number-average primary particle size of 80-150 nm and a second external additive having a number-average primary particle size of 10-60 nm, and an average coverage Cb (%) with the first external additive in the region B is 27-100% and a coverage Ca (%) with the first external additive in the sea region A is 12% or less.

Toner and method for producing the same, and two-component type developer

An image forming apparatus includes a photosensitive member, having a capacitance per unit area of 1.7&#xd7;10(F/m) or larger, an exposure device, which exposes the photosensitive member in order to form thereon an electrostatic image according to image information, a developing device, which develops the electrostatic image with a toner to form a toner image on the photosensitive member, and a transfer device, which transfers the toner image onto a recording material. In forming a solid toner image on the recording material, the exposure device is capable of forming electrostatic images of different potential levels on the photosensitive member, thereby forming toner images of different toner heights on the photosensitive member.

Image forming apparatus having a photosenstive member of high capacitance

A duty ratio Du (%), denoted by (T/(TT))&#xd7;100, is in the range of 60&#x2266;Du&#x2266;80; a magnetic carrier has a resistivity &#x3c1; which decreases in accordance with an increasing electric field strength, and a relative dielectric constant &#x2208; which increases in accordance with an increasing electric field strength; a product of a time constant &#x2208;&#x2208;&#x3c1;(s) of electric charge decay in an electric field strength Edecided by a second peak voltage Vand a dark potential V, and an electric field strength Esatisfies a relation of 20&#x2266;&#x2208;&#x2208;&#x3c1; E(s&#xb7;V/cm); and a time constant &#x2208;&#x2208;&#x3c1;(s) and a relative dielectric constant &#x2208; in an electric field strength E, which is decided by a first peak voltage Vand a bright potential V, satisfy the following relations: &#x2208;&#x2208;&#x3c1;(s)&#x2266;6.0&#xd7;10, and 30&#x2266;&#x2208;.

Image forming apparatus generating electrostatic forces in first and second directions with a predetermined duty ratio

A two-component developer containing a yellow toner and a magnetic carrier, wherein the yellow toner has the characteristics: (i) when the concentration of the yellow toner in a solution of the yellow toner in chloroform is represented by Cy (mg/ml) and the absorbance of the solution at a wavelength of 422 nm is represented by A422, a relationship between Cy and A422 satisfies the relationship of 6.00&#x3c;A422/Cy&#x3c;14.40; (ii) the lightness L* and chroma C* of the yellow toner determined in a powder state satisfy the relationships of 85.0&#x2266;L*&#x2266;95.0 and 100.0&#x2266;C*&#x2266;115.0; and (iii) the absolute value for the triboelectric charge quantity of the yellow toner measured by a two-component method using the yellow toner and the magnetic carrier is 50 mC/kg or more and 120 mC/kg or less.

Two-component developer, replenishing developer, and image-forming method

An image forming apparatus including: an image bearing member; and a developer bearing member bearing a developer including a toner and a carrier, the developer bearing member developing an electrostatic image formed on the image bearing member with the developer, and the developer bearing member being applied with an alternate voltage in order to form an alternate electric field between the developer bearing member and the image bearing member, wherein assuming that electric field intensities Eb and Ed be Eb=|(Vp&#x2212;VL)/D| and Ed=|(Vp&#x2212;VL)/D|, a relationship, 0&#x2267;K&#x3e;K, is satisfied, where K: a gradient at Ed, and K: a gradient at Eb, and wherein a resistivity &#x3c1;b of the carrier at the electric field intensity Eb satisfies 1.1&#xd7;10&#xd7;e&#x3c;&#x3c1;b&#x3c;6.0&#xd7;10[&#x3a9;&#xb7;m] (where: e is the base of natural logarithms; and n=4&#xd7;Eb&#xd7;10).

Image forming apparatus including a developer bearing member with an alternate electric field being applied thereto

An image forming apparatus, wherein the following formulae are satisfied: where (M/S): a toner bearing amount in a maximum density image portion of a photosensitive drum, (Q/M): an average charge amount of the toner in the maximum density portion, Vc: an absolute value of a potential difference between a DC-component of a developing bias and the maximum density portion, Lt: a toner layer thickness of the maximum density portion, Ld: a drum thickness, &#x3b5;t: a relative permittivity of the toner layer, &#x3b5;d: a relative permittivity of the drum, &#x3b5;a vacuum permittivity, Dtmax: a transmission density in a maximum density image portion on the paper after fixation, Dt: a transmission density in an image on the paper when the toner bearing amount on the paper after fixation is 0.1 mg/cm, and &#x3bb;: a transfer efficiency of the toner, 

A two-component developer containing a cyan toner and a magnetic carrier, wherein the cyan toner has the characteristics: (i) when the concentration of the cyan toner in a solution of the cyan toner in chloroform is represented by Cc (mg/ml) and the absorbance of the solution at a wavelength of 712 nm is represented by A712, a relationship between Cc and A712 satisfies the relationship of 2.00&#x3c;A712/Cc&#x3c;8.15; (ii) the lightness L* and chroma C* of the cyan toner determined in a powder state satisfy the relationships of 25.0&#x2266;L*&#x2266;40.0 and 50.0&#x2266;C*&#x2266;60.0; and (iii) the absolute value for the triboelectric charge quantity of the cyan toner measured by a two-component method using the cyan toner and the magnetic carrier is 50 mC/kg or more and 120 mC/kg or less.

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Yokohama, Japan

Manami Haraguchi