A developer collection system comprises a plurality of image carrier members, a plurality of development sections for developing the electrostatic latent images formed respectively on the plurality of image carrier members by means of liquid developers of different colors containing a non-volatile solvent as carrier, an intermediate transfer member for sequentially transferring the developer images developed by the primary transfer sections respectively corresponding to the plurality of image carrier members, superposing them one on the other and carrying and conveying the developer images, an output section for transferring the superposed developer images from the intermediate transfer member onto a sheet on a sheet conveyance route in the secondary transfer section and developer collection means for collecting excessive developers from at least two of the plurality of image carrier members, the plurality of development means, the intermediate transfer member and the output section and at least two of the flow channels from the developer collection means are merged to form a single flow channel.