PURPOSE: To maintain the concentration and viscosity of an ink at an optimum value by adjusting the opening/closing level of a solvent supply value according to the degree of variation of the ink flow rate in a tube for circulation being detected.
CONSTITUTION: An ink 1 stored in a tank 2 is circulated with a pump 5. Here, the ink 1 varies in the viscosity depending on the concentration. The variation of the viscosity corresponds to change in the flow rate of the ink 1 in a circulation tube. So, the change of the flow rate is detected with a flowmeter 6 and are converted into a signal with a controller 7 to control the opening/ closing of a control valve 8. This allows a solvent 3 to be fed into an ink tank 2 in an appropriate amount from a tank 4 thereby invariably maintaining an ink at a constant concentration and viscosity.
MORIYAMA KAZUFUMI
OZAWA SHIGEMI
MARUYAMA HIROSHI
