Method and apparatus for heat treatment of an element by treatment devices engaging the element on both sides

In the apparatus (10) and the method according to the invention, two temperature treatment devices (e.g., laminating rollers 14,16) which are to be contacted with an element to be subjected to heat treatment (e.g., proof 50 with color particles 52), are temperature-controlled. One of the treatment devices (laminating roller 14) is provided with a heating means (22). For tempering the second treatment device (laminating roller 16), the second treatment device is brought into contact with the directly heated treatment device (laminating roller 14). This is carried out as soon as the temperature of the not directly heated treatment device (laminating roller 16) has dropped below a predetermined desired temperature or a predetermined desired temperature range. When the two treatment devices (laminating rollers 14,16) are in mutual contact, the directly heated treatment device (laminating roller 14) is heated to a higher temperature than when the two treatment devices (laminating rollers 14,16) are spaced apart from each other.