Patent ID: 7293849

Claim:
An ink jet recording apparatus comprising: a recording head that ejects ink droplets; an ink tank that supplies ink to the recording head; a waste ink recovering mechanism that recovers ink droplets ejected from the recording head as waste ink; a waste-ink tank which is connected to the waste ink recovering mechanism and stores the waste ink; a diluent tank which is communicated with the waste-ink tank and accommodates a diluent that dilutes the waste ink; and at least one diluent supplier selected from a first diluent supplier which supplies the diluent in the diluent tank to the waste-ink tank to make conductivity of the waste ink in the waste-ink tank substantially the same as the conductivity of the ink stored in the ink tank and a second diluent supplier which supplies the diluent in the diluent tank to the waste-ink tank to make specific gravity of the waste ink in the waste-ink tank substantially the same as the specific gravity of the ink stored in the ink tank.