An inkjet printer for performing printing on a medium by an inkjet scheme, the inkjet printer comprising: a plurality of inkjet heads (12y, 12m, 12c, 12k) that respectively discharge ink droplets of ink of different colors; a medium heating heater that heats the medium onto which the ink droplets were discharged from the respective inkjet heads, by being arranged at a position opposing the plurality of inkjet heads with the medium intervened in between; an opposing position changing unit that sequentially causes each position of the medium in a moving direction to oppose the respective inkjet heads, by feeding the medium in the moving direction that is predeterminedly and relatively set with respect to the plurality of inkjet heads,; and a control unit; wherein the ink is ink that contains a solvent, and is fixed onto the medium by the solvent being dried, and the medium heating heater dries the ink that has been discharged from one of the inkjet heads and struck onto the medium by a time when another one of the inkjet heads further discharges an ink droplet to the struck position of the ink, wherein the plurality of inkjet heads are configured to respectively discharge the ink droplets to regions that are parts of the medium, the regions being at positions that are different in the moving direction, characterized in that the ink jet printer further comprising a main-scan driving unit that causes each of the plurality of inkjet heads to perform a main scanning operation to discharge ink droplets while moving in a main scanning direction that vertically intersects the moving direction, wherein the control unit is configured to control operations of respective units of the inkjet printer so that a relationship among: - a heating temperature by the medium heating heater; - an interval in the moving direction between the regions where the respective inkjet heads discharge the ink droplets; and - a speed by which the opposing position changing unit relatively feeds the medium with respect to the inkjet heads, is set to meet a condition that a surface portion of ink dots of the ink that has been discharged from the one of the inkjet heads and struck onto the medium is dried sufficiently to prevent the smearing between the inks of different colors and in such a manner that the ink dots are sufficiently spread by the time when another one of the ink jet heads further discharges the ink droplet to the struck position of the ink. a plurality of inkjet heads (12y, 12m, 12c, 12k) that respectively discharge ink droplets of ink of different colors; a medium heating heater that heats the medium onto which the ink droplets were discharged from the respective inkjet heads, by being arranged at a position opposing the plurality of inkjet heads with the medium intervened in between; an opposing position changing unit that sequentially causes each position of the medium in a moving direction to oppose the respective inkjet heads, by feeding the medium in the moving direction that is predeterminedly and relatively set with respect to the plurality of inkjet heads,; and a control unit; wherein the ink is ink that contains a solvent, and is fixed onto the medium by the solvent being dried, and the medium heating heater dries the ink that has been discharged from one of the inkjet heads and struck onto the medium by a time when another one of the inkjet heads further discharges an ink droplet to the struck position of the ink, wherein the plurality of inkjet heads are configured to respectively discharge the ink droplets to regions that are parts of the medium, the regions being at positions that are different in the moving direction, characterized in that the ink jet printer further comprising a main-scan driving unit that causes each of the plurality of inkjet heads to perform a main scanning operation to discharge ink droplets while moving in a main scanning direction that vertically intersects the moving direction, wherein the control unit is configured to control operations of respective units of the inkjet printer so that a relationship among: - a heating temperature by the medium heating heater; - an interval in the moving direction between the regions where the respective inkjet heads discharge the ink droplets; and - a speed by which the opposing position changing unit relatively feeds the medium with respect to the inkjet heads, is set to meet a condition that a surface portion of ink dots of the ink that has been discharged from the one of the inkjet heads and struck onto the medium is dried sufficiently to prevent the smearing between the inks of different colors and in such a manner that the ink dots are sufficiently spread by the time when another one of the ink jet heads further discharges the ink droplet to the struck position of the ink. - a heating temperature by the medium heating heater; - an interval in the moving direction between the regions where the respective inkjet heads discharge the ink droplets; and - a speed by which the opposing position changing unit relatively feeds the medium with respect to the inkjet heads,