PURPOSE: To make easy a highly accurate stabilization of ink viscosity by the supply of diluting liquid and to mix the ink and the diluting liquid sufficiently in a short time by the comparison of a detected property value with an established value after the detection of the ink viscosity or its correspondent value.
CONSTITUTION: Diluting liquid supply means which control the flow amount of the former, such as an electromagnetic switch over valve 14, an electromagnetic stop valve or the like, are interposed between a suction port of a circulation pump 12 which recovers the ink of a gutter 9 and the supplying port of an ink diluting liquid reservoir 15. An ink viscosity or its correspondent value is detected, and a detected ink property value is compared with set value, and an instruction is given to the diluting liquid supply means that the diluting liquid should be flowed when it is indicated that the detected value is higher than the set value. Therefore, the diluting liquid is transported to an ink storage section such as an ink tank or the like by a forced suction through the dilute liquid supply means and the circulation pump 12 when the viscosity is too high, a flowing amount is determined roughly by the suction force of the circulation pump 12, and the supply amount is stabilized. Further, the mixing of the ink and the diluting liquid is carried out promptly, since the diluting liquid is transported under pressure to the storage tank 16 by the circulation pump 12, and the diluting liquid is mixed with the ink in the storage section 16, when it is flowed into the storage section 16 under pressure.
AMEYAMA MINORU
FURUKAWA TATSUYA
