Color image forming apparatus having developers in a fixed position with respect to a photosensitive medium

A color image forming apparatus, comprising:

• a photosensitive medium;
• a light exposure unit converting an electrical signal of an image data to be formed to an optical signal and projecting the converted optical signal to the photosensitive medium to form an electrostatic latent image by utilizing an electric potential difference;
• a developing unit comprising developers each having developing rollers and toner-supplying rollers to develop the electrostatic latent image on the photosensitive medium with color toners, wherein the developers are fixed near the photosensitive medium where each developing roller maintains a developing gap with respect to the photosensitive medium;
• a high voltage switching unit supplying the developing rollers and the toner supplying rollers with a high voltage during a developing operation, wherein the high voltage is consecutively supplied to each of the developers in an order of colors where the development of the electrostatic image is performed consecutively in respective colors;
• and
• a compensation voltage supplying unit supplying the photosensitive medium with a compensation voltage to reduce an electric potential difference between the photosensitive medium and the developing rollers of the developers to which the high voltage is not supplied during the developing operation, wherein toner particles of a toner image formed on the photosensitive medium are not attracted to the developing rollers of the developers to which the high voltage is not supplied.

A color image forming apparatus, including a light source, a photosensitive medium having an electrically charged layer to generate an electric potential difference upon exposure to the light source at an electrically charged area of the layer, and a light exposure unit to form an electrostatic latent image on the photosensitive medium by utilizing the electric potential difference, the apparatus comprising:

• a plurality of developers, each having color toner supplied developing rollers to maintain a predetermined developing gap with the photosensitive medium, so as to develop the electrostatic latent image on the photosensitive medium;
• a high voltage switching unit to individually and consecutively supply the developing rollers with a high voltage in an appropriate order to form the electrostatic image such that, during a color image forming operation, one of the developers is operated and the remaining developers are non-operated;
• and
• a plus voltage-supplying unit to supply the photosensitive medium with a plus(+) voltage to reduce an electric potential difference between the photosensitive medium and the non-operated developers such that a toner image and/or the electrostatic image of different colors formed on the photosensitive medium is not attracted to the developing rollers of the non-operated developers.

A color image forming apparatus, including a light source, a photosensitive medium having an electrically charged layer to generate an electric potential difference upon exposure to the light source at an electrically charged area of the layer, and a light exposure unit to form an electrostatic latent image on the photosensitive medium by utilizing the electric potential difference, the apparatus comprising:

• a plurality of developers, each having color toner supplied developing rollers to maintain a predetermined developing gap with the photosensitive medium, so as to develop the electrostatic latent image on the photosensitive medium;
• a high voltage switching unit to individually and consecutively supply the developing rollers with a high voltage in an appropriate order to form the electrostatic image such that, during a color image forming operation, one of the developers is operated and the remaining developers are non-operated;
• and
• a compensation voltage supplying unit to supply the photosensitive medium with a compensation voltage to reduce an electric potential difference between the photosensitive medium and the non-operated developers such that toner particles of a toner image formed on the photosensitive medium are not attracted to the developing rollers of the non-operated developers.