Patent ID: 7397490

Claim:
An image forming apparatus, comprising: transport means that transports a print recording medium including a receptive layer that receives a dye(s) on a substrate having thermal plasticity; travel means that causes travel of a thermal transfer sheet having a dye layer(s) and a protection layer formed thereon to be juxtaposed to one another; a thermal head that applies thermal energy in a state where the receptive layer of the print recording medium opposes the dye layer and protection layer of the thermal transfer sheet and that sequentially thermally transfers the dye layer and protection layer of the thermal transfer sheet onto the print recording medium; and control means that controls the transport means to vary a transport speed of the print recording medium, wherein the control means controls the transport speed of the print recording medium so that the relation of Dy≧Dx is satisfied, where Dx=a variation amount in a thickness of the print recording medium in the event of thermal transfer of the dye layer onto the receptive layer of the print recording medium, Dx being defined in accordance with an expression (1); and Dy=a variation amount in the thickness of the print recording medium in the event of thermal transfer of the protection layer of the thermal transfer sheet onto an image thermally transferred onto the receptive layer of the print recording medium, Dy being defined in accordance with an expression (2), the expressions (1) and (2) being Dx=|Lb−La| (1) and Dy=|Lc−La| (2), where La=thickness of the print recording medium prior to image formation; Lb=thickness of a thinnest portion of the print recording medium after image formation; and Lc=thickness of the print recording medium in the event that a minimum amount of thermal energy capable of thermally transferring the protection layer onto the print recording medium has been applied to the thermal head.