which the ink begins to melt by a temperature controlling device not shown in the figure when the linear pressure the force per unit length of the transfer member that the transfer member applies to the recording medium 16 is in the range from 1 to 10 kg cm the ink is transferred adequately if the linear pressure is above this range problems occur such as wrinkling of the paper unnecessarily thick lines or excessively squashed dots if the linear pressure is less than 1 kg cm a large number of dots do not properly contact the recording medium and resulting in transfer defects or non uniform transfer within an image area which is undesirable the temperature of the image formed by the four color recording heads 10 is kept at the softening point of the ink of 100 u00b0 c and then transferred to the recording medium 16 in this embodiment the material of the surface layer of the ink transfer drum 32 is selected so that the surface energy of the surface layer of the ink transfer drum 32 is approximately the same as the surface tension of the molten ink 20a and is sufficiently lower than the surface energy of the recording medium the ink is transferred from the transfer member 15 to the recording medium 16 because of the difference of the surface energy.