A liquid transfer apparatus includes: rollers configured to transfer supplied liquid to a blanket cylinder; a roller holding device configured to detachably hold the rollers and perform a rotating operation to move any one of the rollers to a predetermined position facing the blanket cylinder; and a contact-separation unit configured to bring the roller held by the roller holding device and disposed at the predetermined position into and out of contact with the blanket cylinder.

Correction values (1-n) according to image area ratios in ranges of a printing plate of a preceding print job corresponding to ink fountain keys (4-1-4-n) are obtained. Opening amounts (1b-nb) of the ink fountain keys (4-1-4-n) corresponding to the image of the printing plate (7) of a next print job are corrected by correction values (1-n) to obtain corrected opening amounts (1b-nb). In a state in which ink in an ink roller group (6) has been decreased by scraping and removing it by an ink scraper blade (15) and in a state in which the opening amounts of the ink fountain keys (4-1-4-n ) have been set to the corrected opening amounts (1b-nb), an ink film thickness distribution corresponding to the image of the printing plate of the next print job is formed on the ink roller group (6).

A liquid transfer apparatus includes: rollers configured to transfer supplied liquid to a blanket cylinder; a roller holding device configured to detachably hold the rollers and perform a rotating operation to move any one of the rollers to a predetermined position facing the blanket cylinder; and a contact-separation unit configured to bring the roller held by the roller holding device and disposed at the predetermined position into and out of contact with the blanket cylinder.