Patent ID: 7341337

Claim:
An ink jet recording apparatus, comprising: an ink container that contains oil-based pigment ink; an ink jet head which includes an ink chamber to contain the ink and a plurality of nozzles as discharge orifices communicating with the ink chamber, and which applies pressure to the ink in the ink chamber for discharging the ink as ink droplets from the nozzles; an ink supply channel which is provided between the ink container and the ink chamber, and which supplies the ink from the ink container to the ink chamber; and a cylindrical filter that is provided in the ink supply channel such that the ink from the ink container enters the cylindrical filter through an outer side of the cylindrical filter, passes inward through the cylindrical filter to be filtered, and exits the cylindrical filter through an open inner portion of the cylindrical filter to be supplied to the ink chamber; wherein the filter has a pore size of 2.2 to 5.8 μm, and an average particle diameter of a pigment of the oil-based pigment ink is 100 to 400 nm, so as to achieve an omission ratio less than or equal to 1.0, where the omission ratio is defined as the number of nozzles (n) at which failure to discharge occurs per 1 hour.