This study describes effects of a thickness of printing papers and a thermal conduction from the printing paper to a platen roller on a temperature transient response of the printing papers through 3 dimensional thermal conduction analysis. Especially, a level of the effects of these factors on the transient temperature response was evaluated. A 3-dimentional analytical model which was composed of the paper and a dot heater was prepared and a transient thermal conduction analysis was performed while changing the condition of heat leak from the paper surface opposite to the thermal head to the platen roller. In order to evaluate the transient temperature response of the paper, temperature rise at the heating point of the test paper after 1 second from the start of the heating was calculated. It is found that that the thickness of the paper and the level of the conduction to the platen roller affect the temperature response of the paper separately. In addition, the change of the thickness and the condition of the conduction also affects the level of the effects of the thermal diffusivity on the temperature response.