PURPOSE: To form a transfer image on an arbitrary area of a record sheet by rotating a platen roller to convey the sheet at the time of not holding a grid roller pair, and forming the image on a marginal area near an end of the sheet in a conveying direction out of an image forming area by a thermal head.

CONSTITUTION: The heat transfer printer comprises a grid roller pair 24 for conveying a record sheet S to hold it therebetween, and a thermal head 21 for holding the sheet S, an ink sheet 29 conveyed by the pair 24 synchronously with the sheet S together with a platen roller 22 to selectively heat the sheet 29 thereby to form a transfer image on an image forming area of the sheet S. In the printer, the roller 22 is rotated at the time of not holding the pair 24 to convey the sheet S, and the image is formed on a marginal area near an end of the sheet in a conveying direction out of the image forming area.