Ricoh Company, Ltd.

Kohki Katoh

Masanori Suzuki

Keiko Shiraishi

Masahide Yamashita

Yohichiroh Watanabe

Toyoshi Sawada

Mitsuru Takahashi

Hiromi Ogiyama

Akihiro Sugino

Yuuji Sawai

Katsuya Kawagoe

Akihiro Kotsugai

Hiroyuki Fushimi

Kazuhito Watanabe

Yasuaki Iwamoto

Osamu Uchinokura

Shinichiro Yagi

Toshiki Nanya

Yasuo Asahina

Takuya Saito

Takahiro Tamiya

Masami Tomita

Tomomi Suzuki

Tomio Kondou

Noboru Kuroda

Kenichi Uehara

Yoshihiro Sugiyama

Yasushi Nakamura

Ryoichi Ito

Yohichiro Watanabe

Satoshi Mochizuki

Masashi Nagayama

Yasuyuki Sanui

A transfer device transfers a visual image from an image carrier to a recording medium. The transfer device includes a first transfer element that moves and receives the visual image from the image carrier on a first surface of the first transfer element, a second transfer element provided opposite to the first surface of the first transfer element to pinch and convey the recording medium through a secondary transfer nip part, a facing roller provided on a second surface of the first transfer element opposite to the first surface thereof, and a constant-current power supply that applies an electric current voltage to a core metal of the facing roller to transfer the visual image from the first transfer element to the recording medium. The electric current voltage applied to the core metal has a polarity equal to a polarity of the visual image and is subjected to a constant-current control.

Transfer device for forming a stable transfer electric field, and an image forming apparatus including the transfer device

A toner for developing a latent electrostatic image to a toner image, including a binder resin, and a magnetic material which is blackened by coating the surface of a magnetic powder with a coloring agent, the magnetic material being in an amount of 10 wt.% to 40 wt.% of the entire weight of the toner, a method of forming an image, using a two-component developer containing the toner, an image formation apparatus using the two-component developer, and a toner container containing therein the toner, and an image formation apparatus equipped with the toner container are proposed.

Toner for development of electrostatic latent images, method of forming images, image formation apparatus, toner container containing the toner therein, and image formation apparatus equipped with the toner container

A color toner including toner particles including a colorant, a binder resin, and a wax; and an external additive including at least one of an inorganic particulate material and a particulate resin, wherein the binder resin includes a polyester resin (A) having a crystallinity and a formula (&#x2014;O&#x2014;CO&#x2014;CR1=CR2-CO&#x2014;O&#x2014;(CH)&#x2014;), wherein R1 and R2 independently represents a hydrocarbon, and n and m are repeating numbers; a resin (B); and a resin (C), wherein the resins (B) and (C) and the wax have an island-sea structure such that the resin (C) is present like islands in a sea of the resin (B) and the wax is substantially included in the resin (C). A toner container, an image forming method, an image forming apparatus and a process cartridge including the color toner are also provided.

Color toner for developing electrostatic images, toner container containing the color toner, and image forming method and apparatus using the color toner

A color toner composition including at least toner particles including at least a binder resin; a colorant and a release agent dispersed in the binder resin; and a titania as an external additive, wherein the colorant has an average dispersion particle diameter not greater than 0.5 &#x3bc;m; the release agent and the binder resin are insoluble to each other; the toner particles satisfy the relationship: 0.05&#x2266;Dw/D&#x2266;0.4, wherein Dw represents an average dispersion particle diameter of the release agent and Drepresents a weight-average particle diameter of the toner particles; and the titania has a segregation rate of from 0.5 to 5%.

Color toner, method for manufacturing the toner, and image forming apparatus and method using the toner

A toner including at least a binder resin; a colorant; and a charge controlling agent, in which the binder resin includes at least a polyester resin having a molecular weight distribution such that components having a molecular weight not greater than 500 are included in an amount of 4% by weight and at least a peak is present in a range of from 3,000 to 9,000 when measured by Gel Permeation Chromatography. In addition, the binder resin does not include a tetrahydrofuran-insoluble compound and the charge controlling agent is a resin charge controlling agent including at least units obtained from a monomer including a sulfonate group; an aromatic monomer including an electron absorption group; and an acrylic ester and/or a methacrylic ester monomer.

Toner, developer, and image forming method and apparatus

A toner, a developing method and apparatus is provided to satisfy both the low temperature fixation property and the hot offset property and that has a wide range of fixing temperature. The toner for an image formation comprises at least metal materials in a binding resin, wherein the toner is measured by a stand-alone type flow tester, and has a softening temperature of 65&#x2dc;77.5&#xb0; C., a flow beginning temperature of 100&#x2dc;120&#xb0; C., a melt temperature by a &#xbd; method is 145&#x2dc;195&#xb0; C., and an average length of a short axis of a primary particle of the metal materials is 0.01&#x2dc;0.4 &#x3bc;m.

Toner for developing electrostatic latent image, developing method and developing apparatus

In an electrophotographic image forming apparatus of the type including a plurality of image carriers arranged along an image transfer belt and an image transferring device configured to transfer toner images of different colors from the image carriers to a sheet being conveyed by an image transfer belt or by way of the image transfer belt by applying a bias to the belt, a bias applying method of the present invention can measure a current leaking between a plurality of high-tension power supply sections or to the ends thereof as AC resistances between respective terminals and therefore to accurately measure the leak currents of DC components. Therefore, when relatively high DC components are selected, a difference in current between a plurality of power supply sections can be maintained constant.

Transfer bias applying method for an image forming apparatus and device for the same

Toner for developing electrostatic latent image, toner cartridge containing the toner and image forming apparatus

An image forming apparatus of the present invention includes a cleaning device for cleaning an intermediate image transfer body. A cleaning blade included in the image transfer body is formed of fluorocarbon resin or a thin layer of fluorocarbon resin is formed on the surface of the intermediate image transfer body. Further, wax is coated on the intermediate image transfer body or wax or lubricant powder is contained in toner. A moving mechanism holds the cleaning blade spaced from the intermediate image transfer body at least when image formation is not under way.

Image forming apparatus including image transfer body with elastic layer and coating layer

A carrier is composed of carrier particles, each carrier particle having a core particle containing at least a magnetic material and a surface coating layer provided on the core particle containing at least a resin, the surface coating layer being constituted of a plurality of regions, the regions being separately formed and joined together to form a complex configuration, and having different phase lags when the surface coating layer is subjected to scanning by phase imaging measurement using a scanning probe microscope in a tapping mode, wherein a region having a phase lag over the average phase lag obtained from E &equals;&Sgr;(E(i)&middot;S(i))/&Sgr;S(i) has an area SO, and SO and &Sgr;S(i) are in a relationship of 10%&lE;SO/&Sgr;S(i)&times;100&lE;90% when each region comprises a component A(i) having an area S(i) and a phase lag E(i), in which i represents the number of regions with different phase lags. A two-component developer employs the above-mentioned carrier.

Carrier and two-component developer for electrophotography

An image forming apparatus comprises a latent image support which supports an electrostatic latent image. A charging unit charges a surface of the image support. A latent image formation unit forms an electrostatic latent image on the image support surface. A developing unit develops the latent image with toner to form a toner image. A transfer unit transfers the toner image from the image support to a recording medium. A transport unit transports the recording medium so that the image support surface is countered to a surface of the recording medium. The surface of the image support has a coefficient of friction ranging from 0.1 to 0.7 according to Euler belt method, and a difference between a speed of the image support and a speed of the recording medium is below 1%, and the image support has an outermost surface containing a filler and a binder resin.

Image forming apparatus, and process cartridge for use in image forming apparatus

The electrophotographic toner according to the present invention comprises a binder resin, a colorant, and a negative charge control agent. The binder resin is polyester and/or polyol. The negative charge control agent comprises components which are (1) sulfonic-acid containing monomers, (2) aromatic monomers having electron-withdrawing groups, and (3) acrylate monomers and/or methacrylate monomers. In particular, substituted phenyl maleimides and substituted phenyl itaconimides are prefereably used as the aromatic monomers. Moreover, n-butyl (meth)acrylates and 2-ethylhexyl (meth)acrylates are prefereably used as the acrylate monomers and/or methacrylate monomers.

Toner, developer and container for the developer, and method of and apparatus for forming an image

A toner for developing electrostatic latent images, including a matrix of a first resin selected from polyester resins, polyol resins and mixtures thereof, a plurality of domains of a second resin dispersed in the matrix and containing a wax. The amount of the wax is 2-15% by weight based on the weight of the toner The matrix is substantially free of domains of the second resin having a maximum diameter of greater than 2.0 &mgr;m. A part of the domains containing the wax having a maximum diameter of at least 0.2 &mgr;m constitutes a part of an outer surface of the toner.

Toner for developing electrostatic latent image and image forming method using same

A toner for developing latent electrostatic images is provided which contains, in a binder resin, at least a coloring agent formed from a metal material. A saturation magnetization of the toner is 0.01 to 10 emu/g, and a true specific gravity thereof is 1.33 to 1.62 g/m . Also provided are an electrostatic charge image developer containing the toner for developing latent electrostatic images, an image forming device, and an image forming method using the toner for developing latent electrostatic images.

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Tokyo, Japan

Kohki Katoh