A technique for supplying ink in a liquid printer, for example, includes an apparatus containing: an ink reservoir containing ink; a supply pump for pumping ink into the ink reservoir; a manifold coupled to the supply pump via an ink supply pipe and through which ink is injected to a gap between a developing roller and a photoreceptor web, and an ink storing portion installed between the ink supply pipe and the manifold and having a sectional area greater than that of the ink supply pipe so that a change in pressure of ink supplied to the manifold from the ink supply pipe is minimized.