Ink supply method and ink supply apparatus

An ink supply method in an ink supply apparatus including an ink fountain storing an ink, a plurality of ink fountain keys arranged in the ink fountain, an ink fountain roller to which the ink is supplied from the ink fountain in accordance with opening ratios of the plurality of ink fountain keys, an ink ductor roller to which the ink is transferred from the ink fountain roller by an ink feed operation, and an ink roller group to which the ink transferred to the ink ductor roller is supplied, comprising the steps of:

• forming, in the ink roller group, an ink film thickness distribution corresponding to an image on a printing plate for printing of a next job;
• dividing, into a plurality of roller subgroups, the ink roller group in which the ink film thickness distribution to be used for printing of the next job is formed;
• performing, after or before division, a throw-on operation for at least a most downstream roller subgroup out of the plurality of roller subgroups, and a plate cylinder on which the printing plate to be used for printing of the next job is mounted;
• and
• supplying ink in at least the most downstream roller subgroup to the printing plate mounted on the plate cylinder by rotating by a predetermined number of times the plate cylinder and at least the most downstream roller subgroup, which are thrown on.