| 摘要 |
PURPOSE:To bring negative pressure in a head damper to a level enough not to break the meniscus of ink, and to eliminate defective printing positively by conducting preliminary open-close operation after the suction rise time of a valve passes and performing main open-close operation after a time shorter than the suction rise time. CONSTITUTION:The open-close operation of a valve 11 is conducted at twice of preliminary opening and closing and main opening and closing, and first preliminary open-close operation I is performed after a time t1 until a void 7 in at least a cap reaches approximately constant maximum negative pressure p1 after a time (a) when a suction pump 10 is started passes. The void 7 in the cap is brought to approximately atmospheric pressure for the opening time t2 of the valve 11 at that time while the opening time t2 represents a minimum time when negative pressure in a head damper 2 is increased up to a value close to approximately atmospheric pressure by sucking ink pulled back up to the nose of a nozzle 4 again by the suction pump 10. Accordingly, negative pressure in the head damper 3 is brought to a level enough not to break the meniscus of ink. |
