Patent ID: 8333463

Claim:
An ink jet recording device comprising: means for supplying under pressure ink from an ink container housed in a main body to a nozzle of a printing head; an electrification electrode for charging ink particles discharged from the nozzle; a deflection electrode for deflecting the ink particles charged by the electrification electrode; a gutter for recovering ink particles which have not been used for printing among the ink particles discharged from the nozzle; means for sucking the ink particles recovered by the gutter to recover them into the ink container; an exhaust circulation path for circulating from the ink container to the gutter exhaust gas containing solvent vapor component, the exhaust gas having been recovered at the gutter together with the ink particles which have not been used for printing; an exhaust path, branched off from the exhaust circulation path, for discharging the exhaust gas to the outside of the device; a densitometer for measuring concentration of the ink in the ink container; means for cooling the exhaust gas provided on the exhaust path to liquefy the solvent vapor component; and means for recovering liquefied solvent vapor component to the ink container; wherein the exhaust gas is discharged to the outside of the main body in accordance with the ink concentration measured by the densitometer, the exhaust gas including low solvent vapor component and the liquefied solvent vapor component is recovered to the ink container.