| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus which grasps an amount of gas dissolved in ink in a recording head and carries out an ink maintenance such as degassing according to the amount, and also to provide a liquid control method of the device. SOLUTION: The amount of gas dissolved in ink in the recording head 50 is estimated. Unused ink in the print head 50 is returned to a sub tank 61 via a circulation passage 100 when the estimated value exceeds a predetermined prescribed one. Since ink to be supplied to the print head 50 from the sub tank 61 is degassed with a degassing device 62 provided upstream of the ink print head 50 in the ink flowing direction, ink with a dissolved gas in an amount less than the prescribed one is supplied to the print head 50. Generation of ink bubbles in the print head 50 is suppressed thereby, to prevent discharge abnormality due to bubbles to be generated in ink. It is constitutively preferable to provide a dissolved oxygen meter downstream of the print head 50 in the ink flowing direction, and to measure an amount of gas dissolved in ink in the print head 50. COPYRIGHT: (C)2005,JPO&NCIPI |
