Patent ID: 8186821

Claim:
A water-based ink for ink jet recording comprising a coloring agent, water, and a water-soluble organic solvent, wherein the ink has a low viscosity suitable for ink-jet recording and in the water-based ink after drying, a tan δ at a frequency of about 100 (1/sec) measured at about 25° C. represented by the following Equation (1) is about 4 or more tan δ= G″/G′ (1) tan δ: loss tangent G′: storage elastic modulus G″: loss elastic modulus; and wherein the tan δ after drying in at least one of the following condition (I) and condition (II) is about 4 or more Condition (I): leave about 1 g to about 10 g of water-based ink at rest under a condition, in which a temperature is about 50° C. to about 70° C. and a relative humidity is about 30% to about 50%, wherein decrease in weight of the water-based ink becomes about 0.01 g or less relative to the water-based ink of 24 hours ago when the weight of the water-based ink is measured every 24 hours Condition (II): leave water-based ink at rest under a condition, in which a temperature is about 50° C. to about 70° C. and a relative humidity is about 30% to about 50%, for about 7 days or more.