Abstract: A photosensitive drum of an image forming apparatus includes a drum main body having a hollow shape, and a vibration damping body spaced from an inner wall of the drum main body, having a hollow shape, formed with a plurality of slits, and expanding and closely contacting the inner wall of the drum main body while the drum main body rotates.

Abstract: An electrophotographic image-forming apparatus and method using a two-component developer comprises a charging roller for charging a surface of a photosensitive medium at a predetermined potential; a developing unit for developing an electrostatic latent image formed on the photosensitive medium; a control unit for determining a developing bias voltage to be applied to a developing roller in relation to a print density level selected by a predetermined selection unit out of a plurality of print density levels set in varying degrees, calculating a surface potential of the photosensitive medium charged by the charging roller, and controlling a charging voltage to be applied to the charging roller in order that an absolute value of a potential difference between the determined developing bias voltage and calculated surface potential becomes higher than a predetermined potential; and a charging voltage adjustment unit for variably adjusting the charging voltage to be applied to the charging roller.

Abstract: An electrophotographic image-forming apparatus using a two-component developer and a print density control are provided.

Abstract: An image forming apparatus having a photoconductive drum to form an electrostatic latent image corresponding to a predetermined image by a laser beam scanned after being electrified to a predetermined electric potential, and a developing roller to rotate together with the photoconductive drum having a developing gap therebetween and to transfer a developer, which is a mixture of a toner and a carrier, to the photoconductive drum to form a toner image on the electrostatic latent image, wherein a linear velocity ratio of a linear velocity of the developing roller to a linear velocity of the photoconductive drum is provided at a predetermined ration, which provides maximum quality of the toner image.

Abstract: A method of controlling an amount of toner charging in an electrophotographic image forming apparatus using a two-component developing agent, and an apparatus using the method. The method comprises counting an agitation time when a toner and a carrier are mixed and are agitated in an agitation region of a developing unit, and if the agitation time reaches a predetermined reference agitation time, supplying a predetermined amount of new toner to the agitation region to prevent overcharging of the toner.

Abstract: A developing apparatus of an electric photographic printer supplying a two-element developing agent to develop an electrostatic latent image formed on a photosensitive medium includes: a housing; a developing agent supplying roller; a developing agent mixing roller; a developing sleeve to transfer mixed developing agent to the photosensitive medium through a developing area formed between the developing sleeve and the photosensitive medium; a fixing magnet disposed inside of the developing sleeve to have a plurality of magnetic poles arranged from the developing area in a circular direction about a center of the fixing magnet; and a magnetic bar disposed on an inside surface of the housing to face one of the magnetic poles of the fixing magnet through the developing sleeve to form a magnetic force brush preventing the developing agent from being scattered as the developing agent passes through the developing area.

Abstract: A developing apparatus of an electric photographic printer supplies a two-element developing agent to develop an electrostatic latent image formed on a photosensitive medium.