| 摘要 |
PURPOSE:To enhance an image recording speed and to prevent the occurrence of wrinkles, by a method wherein, a minimum value gradation of gradation data to be simultaneously transferred is detected, and a voltage to be applied to a thermal head is set to a high level until a transfer density reaches a transfer density for the minimum value gradation and then turned to a low level thereafter. CONSTITUTION:A thermal head 11 is provided with a large number of heating resistors arranged in a line. A gradation data weight minimum value detecting part 13 detects the weight of gradation data by every block from a heat control part 12, detects a step of gradation corresponding to a minimum value gradation data among 64-step gradation data to be synchronously transferred by each heating resistor block of the thermal head 11, and informs the result to a control part 14. The data from the heat control part 12 is stored in a line memory 15 to be imparted to the thermal head 11. A power voltage supplied from a power source 16 to the thermal head 11 is controlled to a high or low level by a power supply control part 17. Therefore, an image recording can be enhanced in speed with sufficient steps of gradation, and the occurrence of wrinkles is prevented. |
