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

A method of forming a color image comprising:

• charging a photoreceptor web to a predetermined charging electric potential;
• scanning light onto the photoreceptor web to sequentially form electrostatic latent images corresponding to respective colors of each of a plurality of optical scanning units installed in order of yellow, cyan, magenta and black colors;
• sequentially developing the electrostatic latent images using yellow, cyan, magenta and black developer applied from yellow, cyan, magenta and black developing rollers;
• squeegeeing the developer used for the development by squeegee rollers, wherein one squeegee roller is installed downstream of each of the developing rollers;
• additionally charging the photoreceptor web, which has a lowered electric potential, after squeegeeing using an auxiliary charger;
• and
• restricting the developer used for the development on the photoreceptor web from being transferred to a next developing roller by providing at least two differently sized development gaps.

A method of forming a color image comprising:

• charging a photoreceptor web to a predetermined charging electric potential;
• scanning light onto the photoreceptor web to sequentially form electrostatic latent images corresponding to respective colors of each of a plurality of optical scanning units installed in order of yellow, cyan, magenta and black colors;
• sequentially developing the electrostatic latent images using yellow, cyan, magenta and black developer applied from yellow, cyan, magenta and black developing rollers;
• squeegeeing the developer used for the development by squeegee rollers, wherein one squeegee roller is installed downstream of each of the developing rollers;
• additionally charging the photoreceptor web, which has a lowered electric potential, after squeegeeing using an auxiliary charger;
• and
• restricting the developer user for the development on the photoreceptor web from being transferred to a next developing roller,
• wherein the restricting of developer from being transferred back to the next developing roller further comprises maintaining a magnitude of an electric field within a predetermined range at development gaps which are between each developing roller and the photoreceptor web, and
• wherein the maintaining of the magnitude of the electric field further comprises:
• installing the developing rollers such that sizes of the development gaps which are respectively between each of the yellow, cyan, magenta and black developing rollers and the photoreceptor web can be increased;
• and
• maintaining a difference in an electric potential between the photoreceptor web and each of the developing rollers at each development gap to be 150V or less, and
• wherein an increase of the difference in the electric potential at each of the development gaps according to the additional charging is compensated for by an increase in size of individual development gaps.