PURPOSE: To miniaturize an air chamber and to shorten a time during which ink is brought to a specified pressure, by a method wherein an ink pressurizing chamber, partitioned with pistons, is mounted to an ink feed pump, while the ink is discharged by increasing one pressure due to a stroke difference of a piston which performs a reciprocable movement, and ink is sucked through the reduction of the other pressure.
CONSTITUTION: An ink pressurizing chamber 14, partitioned with two pistons, is mounted to an ink feed a pump, a plunger 22 and a piston 20 surpass a spring 24 through excitation of a magnet coil 25 to pressurize ink in a pressurizing chamber 15 to discharge it through a check valve 13. Then, the pressurizing chamber 14 is brought to a negative pressure, and ink is sucked through the check valve. If an energizing stops, the plunger 22 and piston 20 restores to the original positions, and ink in the pressurizing chamber 14 is pressurized to suck it into the pressurizing chamber 15 through a check valve 12. Thereby, with a current turned ON and OFF, the piston 20 and the plunger 22 perform a reciprocating movement to pressurize and discharge ink, which reduces time fluctuation of a discharge amount, and enables miniaturizing of the device and sharp shortening of a time during which ink is brought to a specified pressure.
KOBAYASHI MASATO
OKAZAKI TETSUO
TANAKA TOMOAKI
