Ink supplying device for printer and ink supplying method

An ink feeding method for a printing machine advancing and retracting individual ductor rollers pneumatically between an ink fountain roller and an ink transfer roller, both of the printing machine, using:

• an ink feeding device comprising:
• a fixed shaft along which plural individual ductor rollers are aligned and is provided with an air feeding pipe for feeding air;
• plural electromagnetic valves provided for each of the individual ductor rollers and for making air-feeding from the air feeding pipe on in order to advance the individual ductor rollers toward the ink fountain roller;
• and plural springs provided for each of the individual ductor rollers and for retracting the individual ductor rollers toward the ink transfer roller;
• and
• a controller for controlling the electromagnetic valves,
• said method comprising making the electromagnetic valves on by said controller in the order from a deep position to an inlet position along the air feeding pipe, and advancing the individual ductor rollers toward the ink fountain roller in this order.