Ink film thickness control method for ink supply apparatus

An ink film thickness control method for an ink supply apparatus including an ink fountain for storing an ink, a plurality of ink fountain keys whose aperture ratios are independently adjusted to supply said ink in said ink fountain, an ink fountain roller to which said ink is supplied through said ink fountain keys, and an ink ductor roller for supplying said ink supplied to said ink fountain roller to a printing plate through an ink roller group in accordance with a feed operation, comprising the steps of:

• (a) setting the aperture ratios of all said ink fountain keys to an identical value and a rotation ratio of said ink fountain roller at predetermined values when said ink roller group has no ink;
• (b) rotating said ink roller group;
• (c) performing the feed operation of said ink ductor roller a predetermined number of times to uniformly form a first minimum ink film thickness distribution necessary for printing in an axial direction of said ink roller group such that an ink film becomes thinner from upstream to downstream by adjusting aperture ratios of said ink fountain keys and the rotation ratio of said ink fountain roller;
• and
• (d) presetting aperture ratios of ink fountain keys and the rotation ratio of said ink fountain roller to a value corresponding to an image of said printing plate,
• and performing the feed operation of the ink ductor roller a predetermined number of times to superimpose the first ink film thickness distribution on an ink roller group with a second ink film thickness distribution corresponding to the image of said ink printing plate.