An ink jet recording medium for pigment ink, which includes a substrate and a porous ink receiving layer for pigment ink, formed on the surface of the substrate, wherein the ink receiving layer includes a pigment and a binder and has an average surface roughness according to JIS B0601 of from 0. A lower portion of the polycentric and unicentric hinge is attached to a knee cuff about a lower leg of the patient. The control logic unit performs this evaluation by determining the number of cells in the row that will be programmed to each of a plurality of bit states corresponding to the write data.