| 摘要 |
PURPOSE:To cancel a negative pressure in an ink supply passage securely and thereby obtain a satisfactory printing condition by activating an atmosphere opening valve provided halfway through the ink supply passage which supplies ink to a recording head. CONSTITUTION:A recovery device which normalizes an ink discharge through suction of ink from a discharge port is provided for prevention of inferior ink discharging which is caused by the clogging of the discharge port installed on a recording head or the mixing of air from the discharge port. However, when the thermal head develops a faulty discharge due to a negative load which might generate in an ink supply passage by a suction recovery action, this discharge state cannot be normalized only by manipulation. To eliminate the negative load, an atmosphere opening valve 19 is provided halfway through the ink supply passage, and when the discharge is faulty, the atmosphere opening valve 19 is opened, especially immediately after the action to normalize suction. Thus the negative pressure is canceled from the ink supply passage, and further, the part exposed to the atmosphere acts as a pressure buffer, bringing about a normal discharge condition. |
