Samsung Electronics Co., Ltd.

Hyung-jin Ahn

Kyu-cheol Shin

Won-hyung Lee

An apparatus for forming a color image using electrophotography includes a photosensitive drum on which a predetermined electrostatic latent image is formed, a plurality of developing units including a developing roller supplying toner to a surface of the photosensitive drum to develop the electrostatic latent image, and pressure cams sequentially or selectively pressing corresponding ones of the developing units toward the photosensitive drum when the electrostatic latent image is developed. A bracket slide disposed in the apparatus uses tension springs to generate the same normal force in a predetermined range regardless of relative positions of the developing units, and the same normal force are applied to the photosensitive drum from the respective developing rollers while reducing a shock occurring when the developing roller contacts the photosensitive drum.

Apparatus for forming color image using electrophotography

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.

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Gyeonggi-do, South Korea

Hyung-jin Ahn