Abstract: An image forming apparatus includes a moving unit including a conveyer belt which moves a printing medium, an attraction unit to attract the printing medium to the conveyer belt, a transferring unit to transfer developer onto the printing medium, a power supply which supplies transfer power and attraction power to the transferring unit and the attraction unit, and a controller which controls the power supply to supply only one of the transfer power and the attraction power in accordance with a location of the printing medium.

Abstract: An image forming apparatus including: a plurality of photosensitive members on which electrostatic latent images are formed; a plurality of charge units to charge the respective photosensitive members with an electric potential; at least one exposure unit which irradiates light to the respective photosensitive members; a plurality of developer supply devices, which adhere a developer to the respective photosensitive members, to form visible images on a surface of the respective photosensitive members; a transfer unit, which transfers the visible images formed on the respective photosensitive members to a transfer medium; and a plurality of exposure lamps which are mounted between the plurality of photosensitive members.

Abstract: Provided is an electro-photographic image forming apparatus and a method of determining a charging voltage thereof. The electro-photographic image forming apparatus includes: a charge roller for supplying a voltage of a predetermined level to a photoconductor; a transfer roller for transferring a developed image to a printing media by using a developer; a high voltage power supply for supplying a charging voltage at a preset level and a transfer voltage at a preset level to the charge roller and the transfer roller, respectively; and a controller for predicting a charged electric potential deviation based on the transfer voltage to be supplied by the high voltage power supply and for determining a charging voltage level to correct for the predicted charged electric potential deviation. Therefore, the deviation of the charged electric potential caused by the transfer voltage is prevented.

Abstract: An image forming apparatus includes an image former which comprises a photosensitive body and a developing device to apply a developer to the photosensitive body, a power supply which supplies developing voltage to the developing device, a detector which detects a density of an image formed by the image former, and a controller which controls the power supply to adjust a level of the developing voltage if the detected density is out of a permissible range.

Abstract: An image forming apparatus includes a moving unit including a conveyer belt which moves a printing medium, an attraction unit to attract the printing medium to the conveyer belt, a transferring unit to transfer developer onto the printing medium, a power supply which supplies transfer power and attraction power to the transferring unit and the attraction unit, and a controller which controls the power supply to supply only one of the transfer power and the attraction power in accordance with a location of the printing medium.

Abstract: An image forming apparatus including: a plurality of photosensitive members on which electrostatic latent images are formed; a plurality of charge units to charge the respective photosensitive members with an electric potential; at least one exposure unit which irradiates light to the respective photosensitive members; a plurality of developer supply devices, which adhere a developer to the respective photosensitive members, to form visible images on a surface of the respective photosensitive members; a transfer unit, which transfers the visible images formed on the respective photosensitive members to a transfer medium; and a plurality of exposure lamps which are mounted between the plurality of photosensitive members.

Abstract: A charging voltage supply and a method for supplying a charging voltage are provided. The charging voltage supply generates a voltage and branches the generated voltage to at least one charging roller according to voltage applied to a transfer roller. Accordingly, the charging voltage supply can compensate for the charging voltage in view of the reduction of a charging potential of a photosensitive body according to the transfer voltage.

Abstract: An image forming apparatus includes at least one photoconductive medium on which an electrostatic latent image is formed; at least one developing device for developing the electrostatic latent image formed on the photoconductive medium with a developer to form a visible developer image, and a developing performance improving unit for controlling at least one of the photoconductive medium and the developing device to periodically form a patch developer image using developer that has uneven attributes (such as uneven coulomb per mass (Q/M)), and clean and remove the patch developer image. Accordingly, developer having uneven Q/M is periodically used for printing patch developer image and removed, thereby preventing the developer from being used for desired images, and thereby preventing inferior developing of desired images at the uneven-developer generating parts.

Abstract: A method and apparatus for applying a developing bias voltage of an image forming apparatus are provided. When an image is formed on paper, an AC bias voltage and a DC bias voltage are applied in an overlapping manner to the developing roller, and when an image is not formed on paper, the AC bias voltage is turned off and only the DC bias voltage is applied to the developing roller.

Abstract: Provided is an electro-photographic image forming apparatus and a method of determining a charging voltage thereof. The electro-photographic image forming apparatus includes: a charge roller for supplying a voltage of a predetermined level to a photoconductor; a transfer roller for transferring a developed image to a printing media by using a developer; a high voltage power supply for supplying a charging voltage at a preset level and a transfer voltage at a preset level to the charge roller and the transfer roller, respectively; and a controller for predicting a charged electric potential deviation based on the transfer voltage to be supplied by the high voltage power supply and for determining a charging voltage level to correct for the predicted charged electric potential deviation. Therefore, the deviation of the charged electric potential caused by the transfer voltage is prevented.