The diffusion model for the dip pen nanolithography is similar to spreading an ink drop on a paper. Nanolithography uses Atomic Probe Microscope like probes to deliver the ink drop on to the substrate. The model considers the ink to be molecular. Some models have been developed considering fluid ink, some with thiol inks, particulate inks and polymer inks. The models consider the fluid ink with the added factors such as flow rate, detachment rate, effect due to relative humidity, multilayer flow, the ink drop, with meniscus etc., which makes the model complicated. The aim of this paper is to create a generalized diffusion model