An ink-jet printing head and an ink-jet printing apparatus can reduce fluctuation of density of an ink ejected from each nozzle by ejecting ink of different densities from the same nozzle without varying size of an ink droplet, or by controlling ejection of a mixture ink, in which a plurality of inks are mixed, for forming an image. It includes at least a pipeline scheduler, a decoding core, a segmented context memory and a context cache. The second lens element with negative refractive power has a concave object-side surface and a convex image-side surface. Other embodiments are also disclosed.