Hitachi, Ltd.

Hitachi Koki Co., Ltd.

Hitachi Printing Solutions, Ltd.

Other

Hitachi Metals, Ltd.

Ricoh Printing Systems, Ltd.

Hitcahi, Ltd.

Nobuyoshi Hoshi

Teruaki Mitsuya

Seiji Maruo

Masayasu Anzai

Toru Miyasaka

Masashi Yamamoto

Shinya Kobayashi

Tsuneaki Kawanishi

Takao Kumasaka

Ryuuichi Shimizu

Shigenori Yaguchi

Mamoru Okano

Hisao Okada

Isamu Komatsu

Junji Kobayashi

Susumu Akimaru

Hiroyuki Mabuchi

Yasuro Hori

Yasuo Takuma

Shinichi Akatsu

Tadahiro Kaneko

Yutaka Ito

Masaya Adachi

Hiroshi Sasaki

Akira Arimoto

Akio Mukoh

Yoshito Tsunoda

Tatsuya Sugita

Takao Umeda

Kenichi Ito

Hirosada Morishita

Tatsuo Igawa

Kunio Satou

Kazuhito Masuda

Kiyohiko Tanno

Kenichi Kawashima

Kunio Sato

Yuzuru Simazaki

Kazuyoshi Tokunaga

Masayoshi Ishii

Atsushi Onose

Mitsuyoshi Shouji

Shigetaka Fujiwara

Yoshihiko Sano

Masato Yamada

Yoshihiro Gunji

Ikuo Shimokobe

Kozi Kato

Shin-ichi Nishino

An electrophotographic toner containing: a fixing resin, a colorant, and wax. The wax at least contains hydrocarbon wax having a number-average molecular weight of not higher than 600, and polyethylene wax having a number-average molecular weight of not higher than 600, a melting viscosity of lower than 15 mPa&#xb7;s at 140&#xb0; C. and a crystallinity of lower than 95%. A ratio of the hydrocarbon wax to the polyethylene wax is in a range of from 1:10 to 2:1. A maximum of absorption peaks in a heat-up time absorption calorie curve in a DSC curve of the toner measured by a differential scanning calorimeter is at a temperature not higher than 75&#xb0; C. An onset temperature in absorption of heat is not higher than 65&#xb0; C.

Electrophotographic toner and image-forming system

A multi-color printer (and a method therefor) includes a drum-shaped photosensitive body for black toner, a belt-shaped toner carrier for non-black color toner, a first transferring unit for transferring a color-toner image formed on the belt-shaped toner carrier to a medium, a second transferring unit for transferring a black toner image formed on the drum-shaped photosensitive body, the drum-shaped photosensitive body being disposed near the belt-shaped toner carrier, and a fusing unit for fusing to the medium the black toner image and the color toner image transferred to the paper.

Multi-color printer and method therefor

An electro-photographic apparatus includes a photosensitive body in the form of a photosensitive belt disposed for movement along a path in which a major portion of the path extends in a substantially vertical direction, and a plurality of developing units arranged in a vertical stack along one side of the substantially vertical path of the photosensitive body. A transfer unit is disposed adjacent to another side of the substantially vertical path of the photosensitive body, a fixing unit and a paper cassette are provided. A first transporting path is provided along which the print medium is transported in a substantially vertical direction from the paper cassette to the fixing unit via the transfer unit.

Small-size color electro-photographic apparatus

Electrostatic image developing toner includes fixing resin; and wax. The wax is hydrocarbon-based wax. The wax is containing, as its constitutional components, first wax and second wax. The first wax is higher than 1.5 in ratio of weight average molecular weight (Mw) to number average molecular weight (Mn), lower than 10 mPa&middot;s in melt viscosity at 140&deg; C. and higher than 75% and not higher than 85% in degree of crystallinity. The second wax is not higher than 1.5 in ratio of weight average molecular weight (Mw) to number average molecular weight (Mn), lower than 10 mPa&middot;s in melt viscosity at 140&deg; C. and higher than 85% and not higher than 95% in degree of crystallinity.

Electrostatic image developing toner and image forming method

Electrostatic charge developing toner contains at least fixing resin, a coloring agent and wax. Wax having number average molecular weight of not higher than 600 is contained as a component of the wax. A volume average particle size of the toner is in a range of from 5 &mgr;m to 10 &mgr;m. Toner particles each having a particle size of not larger than 4 &mgr;m are contained by 10% or lower by number of the total number of toner particles.

Electrostatic charge developing toner and image forming method using the same

An electro-photographic apparatus having a photosensitive body, a plurality of developing units for forming a toner image on a surface of the photosensitive body by attaching toner on a surface of the photosensitive body, a member for receiving a print medium, a first transporting path including a printing portion for transferring one toner image in a substantially vertical direction from the photosensitive body onto one side of the print medium and a fixing portion for fixing the transferred image so as to have a printed print medium and a second transporting path disposed substantially in parallel to and coupled to the first transporting path for returning the printed print medium to the first transporting path for enabling transfer of another toner image on an opposite side on the printed print medium. The printed print medium is transported along the first transporting path for fixing the transferred image on the opposite side of the printed print medium by the fixing portion. The developing units are vertically stacked.

In an electrophotographic apparatus, regions having at least three different potential levels Vc, Vw, and Vr are formed on a photosensitive member by using an exposing device, and developing processes respectively using colored particles of different kinds are performed by normal development and reversal development on two potential levels Vc and Vr excluding the intermediate potential level Vw. The apparatus has an auxiliary exposing unit for forming a fringe development preventing potential in an edge of an image forming region in order to prevent fringe development from occurring. The auxiliary exposing unit sets an auxiliary exposure amount by performing pulse-width modulation on a laser driver.

Electrophotographic apparatus having a fringe development preventing mechanism

A printing system is provided which ensures easy formation of a plate and regeneration of the plate for continued use. The press plate used in a the printing system to form an image using a water-based ink is characterized in that, (I) prior to formation of a latent image, the surface forming the latent image exhibits extra ink-repellency to the ink to be used; (2) the press plate allows a water soluble material forming the latent image to be deposited thereon; (3) the latent image can be formed by allowing the water soluble material to be deposited on the press plate surface; and (4) the press plate can be regenerated as a plate which allows a new latent image to be formed by washing the press plate with water and drying it, upon completion of ensuing processes of development and transfer.

Printing plate and printer using it

An electrophotographic printing apparatus using electric potential dividing development processing without the occurrence of primary fringe and fringe caused by auxiliary exposure has reverse electric fields causing primary fringe and fringe caused by auxiliary exposure adjusted to be nearly equal to each other. The auxiliary exposure is applied to an area surrounding one image, and an electric potential of an intermediate electric potential zone is brought close to a bias electric potential of another image which is not subjected to auxiliary exposure. Further, a white portion to produce a reverse electric potential therein at the rear end of an electric potential portion to be developed with toner, relative to a rotating direction of a developing roller, is exposed with a light intensity forming an electric potential between an electric potential developing an image with toner and the intermediate electric potential, and portions at the front end and the sides are exposed with a light intensity forming the intermediate electric potential.

Electrophotographic printing apparatus using electric potential dividing

An electro-photographic apparatus including a photosensitive body, a plurality of developing units for forming a toner image on a surface of the photosensitive body by attaching toner on the surface of the photosensitive body, an intermediate transfer body for having the toner image transferred thereon and for transferring the toner image onto a print medium, and a paper cassette for containing the print medium. The paper cassette and the developing units are arranged to be horizontally detachable in the same direction.

Electrophotographic recording device and exposure controlling device

Color electrophotographic printer with belt control

A multi-color image forming apparatus is capable of decreasing the amount of ozone generation which occurs during the formation of a multi-color image. For this purpose, a charged latent image having a tri-level electric potential is formed on a positive charging photoconductor by a charging means and an exposing means. A first color toner having one of a positive polarity and a negative polarity is caused to adhere onto one of the charged latent images having the highest electric potential level at a first developing unit of the apparatus, and a second color toner having the other polarity is caused to adhere onto the other of charged latent images having the lowest electric potential at a second developing unit of the apparatus. After that, the polarity of the toner having the negative polarity is reversed using a positive corona produced by a pre-transfer charging means to unify both polarities of the two color toners, and then both toners having the unified polarity are s transferred onto a sheet of paper.

Multi-color image forming apparatus having arrangements for reducing

A dielectric belt 24 is retracted from a photoreceptor 2 before printing, and electrophotographic processes including a process of forming an electrostatic latent image, a developing process and a cleaning process except for a transferring process are repeated. During the repetition of the electrophotographic processes, a surface electric potential in the background of the photoreceptor 2 is measured by the electric potential sensor 10. Alternatively, a quantity of toner adhering to the background of the photoreceptor 2 is measured by the toner sensor 37 and the toner electric charge sensor 36. When the measured values are lower than the reference values, it is judged that no fringe image is generated in the recording condition, and the printing operation is carried out.

Color image forming apparatus and color image forming method thereof

By employing a developer using ferrite system carriers, a developing process can be carried out using a low brushing force by a magnetic portion having the same polarity in a developing unit in a developing roller. A relationship between a circumferential speed Up (mm/sec) of a photoconductor, a ratio K of a circumferential speed of a developing sleeve of the developing roller to the circumferential speed of the photoconductor, and a developing potential difference .DELTA.V (V) is set to 1.5.ltoreq.(K.times..DELTA.V/Up).ltoreq.2.1.

Developing apparatus and picture image forming apparatus

Growing community of inventors

Hitachinaka, Japan

Nobuyoshi Hoshi