Patent ID: 7213915

Claim:
An ink jet printer comprising: an image forming section for forming an image by ejecting a pigment ink toward a recording medium in which a surficial layer includes thermoplastic fine particles, in a case; a fixing member for fixing the image by heating and pressurizing the recording medium on which the image is formed by the image forming section; a drying member for drying the ink used to form the image before the image is fixed to the recording medium by the fixing member; a temperature detecting member for detecting a temperature in the case; a humidity detecting member for detecting a humidity in the case; a drying member control section for controlling an operation of the drying member in accordance with the temperature detected by the temperature detecting member and the humidity detected by the humidity detecting member; a vapor volume calculating section for calculating a vapor volume per unit volume of air in the case in accordance with the temperature detected by the temperature detecting member and the humidity detected by the humidity detecting member; and a vapor volume judging section for judging whether the vapor volume calculated by the vapor volume calculating section is not less than a predetermined value; wherein the drying member control section operates the drying member when the vapor volume judging section judges that the vapor volume calculated by the vapor volume calculating section is not less than the predetermined value.