APPARATUS FOR APPLYING GATING AGENTS TO A SUBSTRATE AND IMAGE GENERATION KIT

Apparatus and methods for controlling application of a substance to a substrate involve the use of one or more gating agents that block the substance from or attracts the substance to the substrate. The apparatus and methods may utilize ink jet technology to apply the gating agent directly to the substrate or to an intermediate surface. The substance may be an ink, an electrically conductive material, a magnetic material, a carrier for a therapeutic, diagnostic, or marking substance other than an ink, a carrier or any other substance.