An ink for inkjet recording apparatuses is provided in which an adsorbed resin proportion calculated from a total resin mass and a free resin mass in the ink is at least 0.95 and less than 1.00, the ink containing in specific amounts, respectively: water; a pigment dispersion including a resin with a molecular weight in the range of 35,000 to 140,000 and a specific amount of pigment; glycerin and 1,3-propanediol as humectants; and 1,2-octanediol, which has 8 carbon atoms, as a high penetrating agent, and further containing a C2-C4 monoalkyl ether of a polyhydric alcohol as a penetrating agent.