Patent ID: 7315709

Claim:
An image forming apparatus comprising: a main image forming apparatus having a developing section and capable of being independently driven for printing an image onto a paper fed on the basis of input image information; at least one sub-image forming apparatus mounted to the main image forming apparatus in sequence, the sub image forming apparatus having a developing section and modularized to perform a printing operation according to a control command; a main paper feeding unit connected to the main image forming apparatus for feeding a paper to the main image forming apparatus; at least one sub-paper feeding unit connected to the main paper feeding unit in sequence for feeding a paper to the sub-image forming apparatus, respectively; and a control section for selectively controlling the operation of the main image and sub-image forming apparatuses and respective paper feeding units on the basis of input image information in a manner that printing operations are performed either in one of the main image or sub-image forming apparatus, or simultaneously in the respective main image and sub-image forming apparatuses; wherein the main image forming apparatus comprises the control section; wherein the at least one sub-image forming apparatus includes a first transfer path for guiding a paper fed from the sub-paper feeding unit, so that the paper passes through the developing section; a second transfer path for transferring a paper fed from the sub-paper feeding unit to another sub-image forming apparatus; and a guide member disposed at a junction between the first transfer path and the second transfer path for selectively determining the transfer direction of the paper being transferred.