| 摘要 |
PURPOSE:To keep both an ink feeding pressure and an ink drip injection speed constant by sensing an ink pressure normally at an ink pressure sensing part and by changing a number of rotation of non-pulsatory rotary pump by a driving control circuit in response to a change in the ink pressure. CONSTITUTION:When the screw pump 2 is driven and the three-way valve 3 is released, ink is fed under a pressure to the head 4 to form the ink drip 15. During the operation, the ink pressure to be applied to the head 4 is always sensed by the pressure sensing element 16. In reference to a result of sensing performed by the pressure sensing element 16, a rotational speed of the screw 10 is increased or decreased to keep the ink feeding pressure constant. A control operation for a number of rotation of such a servo-motor 13 is performed by the driving control circuit 14. Thus, even if a viscosity of the ink is varied due to a change of a temperature of surrounding air, an injection speed of the ink drip 15 fed from the head 4 is kept constant, a printing condition is always kept constant and a printing image is stabled. |
