Color erasing apparatus and method of controlling temperature of heat source in color erasing apparatus

A method for erasing images comprising:

• conveying a paper on a conveying path, the paper having an image formed by heat-erasable coloring material;
• providing a sensor signal indicative of a thickness of the paper being conveyed on the conveying path;
• detecting thickness of the paper based on the sensor signal;
• conveying the paper through a color erasing unit including a heating unit configured to heat the paper to erase the image;
• and
• controlling a temperature of the heating unit based on the detected thickness of the paper, wherein
• when the detected thickness of the paper is greater than a first predetermined thickness, the temperature is controlled to be a first temperature,
• when the detected thickness of the paper is less than the first predetermined thickness, the temperature is controlled to be a second temperature less than the first speed, and
• when the detected thickness of the paper is less than a second predetermined thickness smaller than the first predetermined thickness, the temperature is controlled to be a third temperature less than the second temperature.

A paper heating apparatus comprising:

• a heating unit configured to heat a paper;
• a sensor configured to output a sensor signal indicative of a thickness of the paper;
• a paper thickness detector configured to determine the thickness of the paper based on the sensor signal;
• a conveying unit configured to convey the paper through the heating unit;
• and
• a heating unit controller configured to control a temperature of the paper conveyed through the heating unit based on the thickness of the paper determined by the paper thickness detector, wherein
• when the thickness of the paper determined by the paper thickness detector is greater than a first predetermined thickness, the conveyance temperature is controlled to be a first temperature,
• when the thickness of the paper determined by the paper thickness detector is less than the first predetermined thickness, the temperature is controlled to be a second temperature less than the first temperature, and
• when the thickness of the paper determined by the paper thickness is less than a second predetermined thickness smaller than the first predetermined thickness, the temperature is controlled to be a third temperature less than the second temperature.