Samsung Electronics Co., Ltd.

Kyu-cheol Shin

In-yong Song

Myung-kook Ahn

Masahiko Itaya

Tsutomu Sasaki

Joong-gwang Shin

Naonori Kurogawa

Tsutomu Teraoka

Jong-woo Kim

Sung-dae Kim

Jeong-hun Pang

Yong-su Kim

Yong-baek Yoo

Kwang-ho No

Woo-yong Park

Won-hyung Lee

Geun-Yong Park

Seung-young Byun

Hyun-seong Shin

Wan-Ha Kim

Hyung-jin An

Sam-seuk Choi

Jun-hee Cho

Hee-guk Kwak

Sang-hyeon Byeon

Hyung-jin Ahn

Nam-ryoung Kim

Seung-deok An

Myung-Kook 2-909 Samsung 1-Cha Apt Ahn

A developing unit which forms an image on a photosensitive medium, includes a housing which accommodates a developer, a magnetic cylinder having a catch pole which picks up the developer in the housing by a magnetic force, and a main pole which couples a carrier among the picked-up developer, a sleeve rotatably installed on a circumference of the magnetic cylinder to form a magnetic brush having a predetermined width on the circumference by the developer picked up by the catch pole, and a sealing member provided at opposite end parts in an axial direction of the sleeve to prevent a leak of the developer, wherein a width Wof the sleeve, a magnetized width Wof the main pole, a magnetized width Wof the catch pole, and a width Wof the magnetic brush satisfy W&#x3e;W&#x3e;W&#x3e;W.

Developing unit and image forming apparatus employing the same

An electrophotographic image forming apparatus and a developing method thereof are provided. The electrophotographic image forming apparatus includes an image carrier body on which an electrostatic latent image is formed, a developing roller which faces the image carrier body and supplies toner to the electrostatic latent image formed on the image carrier body, and an anti-toner-dispersion element which faces an outer circumferential surface of the image carrier body between an exposing section where the electrostatic latent image is formed and a developing section where the electrostatic latent image is developed by the developing roller. A collection bias is applied to the anti-toner-dispersion element to collect dispersed toner from the developing roller.

Electrophotographic image forming apparatus and developing method thereof

A toner density estimating method for a two-component developer is provided. The toner density estimating method includes: sensing photo-reflectance of a test pattern having a plurality of grayscales formed by using toner; calculating a rate of change of the photo-reflectance according to the grayscales of the test pattern; and estimating a toner density based on the rate of change. Accordingly, it is possible to accurately estimate the toner density irrespective of the influence of changes in temperature, humidity, or other external factors.

Toner density estimating method and apparatus using toner image and toner supplying method and apparatus

An electrophotographic image forming device is provided which includes an image holder on which an electrostatic latent image is formed. A magnetic roller has a magnetic brush including nonmagnetic toner and a magnetic carrier using a magnetic force. Donor rollers are provided which have toner layers that are received from the magnetic roller on an outer circumference of each of the donor rollers. The donor rollers are located opposite to the image holder to develop the toner onto the electrostatic latent image.

Electrophotolithographic image forming device and image developing method

A hybrid type developing apparatus and method forms a magnetic brush of non-magnetic toner and a magnetic carrier on a circumference of a magnetic roller forms a uniform toner layer on the circumference of a donor roller using only toner from the magnetic roller, and develops an electrostatic latent image on an image receptor. The hybrid type developing apparatus includes: a plurality of electrodes on the circumference of the donor roller; first and second brush electrodes in an upstream area and a downstream area, respectively, of the donor roller facing the magnetic roller with respect to a direction of rotation; and a bias applying device for applying a recovery bias to the first brush electrode to remove toner from the donor roller and a supply bias to the second brush electrode to supply toner from the magnetic roller to the donor roller.

Hybrid type developing apparatus and developing method

A color image forming apparatus which, in a sequential order for each of plural colors of a composite color image, charges plural photosensitive bodies, exposes electrostatic latent images on the plural photosensitive bodies, develops latent images on the photosensitive bodies into color images, and transfers the color images to sequentially form images of each of the plural colors one on another to form the composite color image and transcribing the composite color image onto a printing medium. The color image forming apparatus includes: plural charging units which perform the charging process for each of the plural colors; plural exposing units which perform the exposing process for each of the plural colors; plural developing units which perform the developing process for each of the plural colors; and plural transfer units which perform the transfer process for each of the plural colors.

Color image forming apparatus

A developing device for a liquid electrophotographic image forming apparatus is provided. The developing device may have a developing roller, which supplies ink to a photosensitive body on which an electrostatic latent image is formed and develops the electrostatic latent image. The apparatus may include an ink reservoir in which ink supplied to the developing roller is accommodated, and an ink removal unit, which removes ink remaining in the ink reservoir after a development operation is performed. The ink removal unit may comprise an ink removal member rotatably installed in the ink reservoir that exhausts ink through a through hole formed under the ink reservoir. A driving member rotates the ink removal member. An ink cartridge stores ink exhausted through the through hole.

Developing device for liquid electrophotographic image forming apparatus

An electrophotographic image forming apparatus and a method of controlling development includes a current measuring unit to measure a developing current flowing between a developing roller and a photosensitive medium, and a controlling unit to calculate at least one of a thickness of a photosensitive film of the photosensitive medium, a thickness of a developer on a surface of the developing roller, and the quantity of development on the surface of the photosensitive medium using the measured developing current, and then display information concerning replacement of consumables, or control a developer supply vector and a development vector on a basis of the calculated value. In addition, the method of controlling development has measuring developing currents; calculating a capacitance of a photosensitive medium, the thickness of the developer, and an exposure potential of an electrostatic latent image using the measure developing currents; calculating the thickness of the photosensitive film, the thickness of the developer, and the quantity of development using the calculated values; and comparing the calculated values of the thickness of the photosensitive film, the thickness of the developer, and the quantity of development with preset standard values, respectively, and then displaying information concerning replacement of the photosensitive medium and the developer or controlling a developer supply vector and a developing vector.

Electrophotographic image forming apparatus and method of controlling development using information concerning replacement of consumables

An image forming system of an electrophotographic printer. The system includes a photosensitive body on which an electrostatic latent image is formed, a developing unit which develops the electrostatic latent image with a developer, a transfer body onto which the developed image is transferred, a first image charging unit which charges the image so as to increase an electric adhesive force of the image transferred onto the transfer body, a second image charging unit which charges the image so as to reduce the electric adhesive force of the image transferred onto the transfer body in the rear of the first image charging unit, and a transfer unit which transfers the image passing through the first and second image charging units onto paper. When the image is transferred onto the transfer body, the first image charging unit increases the electric adhesive force of the image and prevents the image from dispersing, and the second image charging unit reduces the adhesive force suitable for transfer just before the image is transferred onto the paper, and thus the clear image can be maintained, and a transfer efficiency can be improved.

Electrophotographic printer having image charging unit to reduce adhesive force of transferred image and method thereof

A liquid electrophotographic image forming apparatus using an ink developing solution having a high concentration where a non-volatile carrier is used as a dispersion solvent includes a photosensitive body, a charge unit increasing a potential of the photosensitive body to a charge potential, an exposure unit projecting a beam onto the photosensitive body and forming a latent electrostatic image, a developing solution supply unit supplying a developing solution to the photosensitive body, the developing solution having a high concentration where a non-volatile carrier is used as a dispersion solvent, a developing unit receiving the developing solution having the high concentration to form a developing film having the high concentration and to develop the latent electrostatic image, a transfer unit contacting the photosensitive body and moving the developed image to a recording medium, and a fixing unit fixing the transferred image in the recording medium at a temperature lower than a flash point of the non-volatile carrier. By using the non-volatile developing solution having the high concentration, a smell generating due to vapor of a carrier can be prevented, and an image forming apparatus having a simple structure can be provided.

Liquid electrophotographic image forming apparatus using non-volatile ink carrier

A liquid developer imaging system and a method using the system for developing an image, including a cartridge for containing a developing solution; a developing container for receiving the developing solution supplied from the cartridge via a predetermined supply line; a developing roller partly submerged in the developing solution contained in the developing container, installed to be rotated facing a photosensitive object; and a metering blade for scraping off the developing solution coated on the surface of the developing roller to a predetermined thickness, is provided. According to the system, a developing supply structure can be considerably simplified because a high-density developing solution is directly used in developing an image without a process of diluting the solution, and an image can be developed to have high definition because the concentration of the developing solution coated on the developing roller is regularly controlled by a metering blade.

Liquid developer imaging system

An image forming apparatus for and a method of compensating for development mass per area includes a photosensitive body on which an electrostatic latent image for an image is formed, a charger charging the photosensitive body, a developing unit developing the electrostatic latent image of the photosensitive body, a measuring unit measuring a charge current flowing through the photosensitive body from the charger, a comparator comparing the charge current with a reference current, and a controller controlling a developing unit control variable so as to compensate for a variation in a thickness of the photosensitive body according to an output of the comparator. A time indicator of a display informs a user whether the photosensitive body has to be replaced, and deterioration of an image quality caused by a decrease in the thickness of the photosensitive body can be prevented when a potential of the developing unit is controlled.

Image forming apparatus for and method of compensating for variation in thickness of photosensitive body and development mass per area

A liquid electrophotographic color image forming apparatus includes a main charger for charging a surface of a photoreceptor web to a predetermined charging electric potential, an optical scanning unit for scanning light onto the photoreceptor web to form an electrostatic latent image, and developing rollers for yellow, cyan, magenta and black colors, sequentially installed in a direction that the photoreceptor web circulates, for developing the electrostatic latent image using developer for each color. Further included are auxiliary chargers for cyan, magenta and black colors, installed downstream of each of the developing rollers, for additionally charging the photoreceptor web, the electric potential of which is lowered after development for each of yellow, cyan and magenta colors. In the above apparatus, when development gaps between each of the developing rollers and the photoreceptor web are respectively defined as G , G , G and G sequentially in a direction that the photoreceptor web proceeds, to restrict an increase of the intensity of an electric field at each development gap according to the additional charging, each of the developing rollers are installed to satisfy the condition that G &lE;G &lE;G &lE;G .

Liquid electrophotographic color image forming apparatus and color image forming method for reducing the transfer of toner to a developing roller

An electrophotographic printing apparatus having a structure so that differences between surface energies of components of the electrophotographic printing apparatus contributing to image transfer are maintained within predetermined ranges, and an image transferring method thereof. The electrophotographic printing apparatus includes a photosensitive medium, developing units, a drying roller and a transfer unit having a transfer roller, whereby the peeling force (PF ) of the drying roller is in a range of 0 gram force per inch (gf/inch)&lE;PF &lE;300 gram force per inch (gf/inch), the peeling force (PF ) of the photosensitive medium is in a range of 0 gram force per inch (gf/inch)&lE;PF &lE;80 gram force per inch (gf/inch), and the peeling force (PF ) of the transfer roller is in a range of 200 gram force per inch (gf/inch)&lE;PF &lE;500 gram force per inch (gf/inch), respectively, when the peeling forces are measured. The image transferring method for an electrophotographic printing apparatus includes the steps of adjusting the peeling force (PF ) of the drying roller, the peeling force (PF ) of the photosensitive medium, and the peeling force (PF ) of the transfer roller to be within the above mentioned respective ranges.

Growing community of inventors

Seoul, South Korea

Kyu-cheol Shin