Developing device driver and an image forming apparatus using the same

A color image forming apparatus comprising:

• at least one photoconductive medium on which an electrostatic latent image is formed;
• at least two developing devices, each developing device comprising a developing roller to form a developer image by developing the electrostatic latent image formed on the photoconductive medium with developer;
• a transfer belt onto which the developer images are transferred, thereby forming a color image;
• a transfer roller to transfer the color image formed on the transfer belt onto a recording medium;
• and
• a developing device driver to drive the developing rollers, the developing device driver comprising a driving source, a driving gear connected to the driving source, a single power switching gear engaged with the driving gear and rotated along a circumference of the driving gear, a rotation unit to rotate the power switching gear, and developing roller gears which are adapted to be connected with and separated from the power switching gear, the developing roller gears being provided to the developing rollers, wherein said single power switching gear is adapted to be sequentially connected with and separated from each of the developing roller gears.

A color image forming apparatus comprising:

• a photoconductive medium to form electrostatic latent images;
• a plurality of developing rollers to develop electrostatic latent images formed on the photoconductive medium, each developing roller having a developing roller gear to drive the developing roller;
• and
• means to selectively drive the developing rollers comprising,
• a driving source,
• a driving gear connected to the driving source,
• a single power switching gear engaged with the driving gear and rotated along a circumference of the driving gear, and
• a rotation unit to rotate the power switching gear so that the power switching gear is sequentially placed into contact with each of the developing roller gears of the plurality of developing rollers to transmit power from the driving gear to the selected developing roller gear.