Ricoh Company, Ltd.

Kazuhito Watanabe

Hiroshi Yamashita

Masami Tomita

Shigeru Emoto

Chiaki Tanaka

Tsunemi Sugiyama

Masahide Yamashita

Masanori Suzuki

Yohichiroh Watanabe

Keiko Shiraishi

Kohki Katoh

Takahiko Tokumasu

Kazuhiko Watanabe

Hiroshi Nakai

Nozomu Tamoto

Satoshi Hatori

Shinji Tamaki

Yasuo Suzuki

Nekka Matsuura

Satoshi Narumi

Haruji Mizuishi

Tsutomu Katoh

Kohichi Ohshima

Tetsuroh Tanigawa

Kenji Sugiura

Yasushi Nakazato

Hiroshi Yamada

Yasuaki Iwamoto

Toshiki Nanya

Misao Tanzawa

Takashi Okada

Naohiro Watanabe

Noriyoshi Tarumi

Toyoshi Sawada

Mitsuo Aoki

Fumihiro Sasaki

Yasuo Asahina

Shinichi Kuramoto

Masahiko Shakuto

Takuya Saito

Tomio Kondou

Kumi Hasegawa

Daichi Yamaguchi

Youichi Maekawa

Kouki Katoh

A carrier and a dummy toner are stored in a developing unit of a process cartridge in a brand new status. A plurality of process cartridges corresponding to a plurality of color toners is used in common. The color toners are respectively supplied to the developing unit from toner supply units after the process cartridges in the brand new status are installed in installation sections in a main unit of an image forming apparatus.

Image forming apparatus, process cartridge, developing unit, and image forming method

A process cartridge is provided with a frame body made up of at least first and second frame bodies that are movable relative to each other to form a space, a frame body positioning member positioning the first and second frame bodies, a latent image bearing member supported by the frame body and replaceable via the space formed by the first and second frame bodies, a developing unit supplying a developing agent to the latent image bearing member, and a developing position determining member. The developing position determining member is disposed at a non-overlapping position relative to the frame body positioning member, and positions the developing unit with respect to the frame body.

Process cartridge including at least one replaceable member and image forming apparatus

A dry toner contains fine particles having average sphericity of 0.93 to 0.99, a content of the fine particles having a particle diameter of 2 &#x3bc;m or less in the dry toner is 20% by number or less. A method for manufacturing a dry toner includes a process for dispersing in an aqueous medium containing water and a water-soluble organic solvent, a toner composition contained in an organic solvent by using fine solid dispersing agent; and a process for contracting volume of the dispersed toner composition. Further, the image forming apparatus having a photoconductor; a charger for charging the photoconductor; a light irradiator for irradiating the electrophotographic photoconductor to form a latent electrostatic image; a developer for developing the latent electrostatic image to form a developed image; and a transfer for transferring the developed image to a recording material, and the developer contains the dry toner abovementioned.

Dry toner, method for manufacturing the same, image forming apparatus, and image forming method

An image forming apparatus of the present invention includes a movable body to be charged and a charger including a charging member that contacts or adjoins the body to be charged and applies a voltage, including an AC component, to the charging member for thereby charging the body. A protection substance for protecting the surface of the body from deterioration ascribable to charging is caused to exist on the body. The number of particular elements, contained in the protection substance and detected by an X-ray photon spectral analyzer (XPS) in a zone where the charging member charges the body, is held in a particular ratio to the total number of all elements constituting the outermost surface of the body and also detected by the XPS.

Image forming apparatus using a contact or a proximity type of charging system including a protection substance on a moveable body to be charged

A toner composition including toner particles including a binder resin; and a colorant, and a charge controlling agent which is at least located on a surface of the toner particles, wherein the toner composition has a spherical degree of from 0.96 to 0.99, and wherein the toner composition satisfies the relationship: 10&#x2266;M/T&#x2266;1,000 wherein M represents a quantity of an element on a surface of the toner particles in units of % by weight, wherein the element is included only in the charge controlling agent, and is one of elements of second to fifth periodical elements in the long form periodic table other than hydrogen, carbon, oxygen and rare gas elements; and T represents a quantity of the element in the toner composition in units of % by weight.

Toner composition and method for manufacturing the toner composition

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 charging device of the present invention includes a charging member and a body to be charged forming a nip therebetween. Charge-promoting conductive grains, frictionally charged to polarity opposite to the polarity of a voltage applied to the charging member, are held at the above nip. The charging device is operable in a cleaning mode for cleaning the body to be charged.

Process cartridge and image forming apparatus with toner fed cleaning mode

A dry toner including at least a modified polyester as a toner binder, wherein the modified polyester has a main peak in a molecular weight region of 1000 to 30000 in a molecular weight distribution as measured by GPC, contains 1 to 10% of a component having a molecular weight of at least 30000, and has an Mw/Mn ratio of not greater than 15.

Dry toner and image forming method using same

A method of fixing toner in a belt fixing unit having a fixing roller; a heating roller; an endless fixing belt binding the heating roller and the fixing roller under tension therebetween; a pressure roller disposed to face the fixing roller intervening the fixing belt; and a fixing heater disposed inside one of the pressure roller and the heating roller, the method of fixing includes: a step for fixing a toner image on an image fixing material by conveying the toner image on the image fixing material in between a portion of the fixing belt not touching the fixing roller and the pressure roller; featured by the toner particle being spherical having a roundness of 0.96 or more and contains a colorant and resin component containing a modified polyester resin.

Method for fixing toner

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

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Kanagawa, Japan

Kazuhito Watanabe