Abstract: In a method for controlling the actual temperature of an intermittently operated heating means, at least one operating parameter is measured for a predetermined measuring time period (T) during a switch-on interval (86) of the heating means. On the basis of the measured value of the at least one operating parameter, the actual temperature of the heating element is detected. The length of the current switch-on interval (86) is changed in dependence on the result of a comparison between the actual temperature and a predetermined desired temperature. The minimum length of each switch-on interval (86) is equal to the measuring time period (T). The measuring time period (T) is selected to provide that, during the length of the measuring time period (T), the thermal energy supplied to the heating means is less than the thermal energy emitted during the following switch-off interval (88) extending up to the next switch-on interval (86).

Abstract: 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.

Abstract: An apparatus (14) for developing an exposed proof (16) provided with a visible light absorbing composition such as color particles or pigments includes a transport means (22-28, 36) for transporting the proof (16) along a treatment liquid dispenser unit (30, 32) and a take-off device (44, 38, 40) for removing detached composition from the proof (16). A tempering device (48) is provided for keeping the treatment liquid, which in the dispenser unit (30, 32) is applied onto the proof (16), at the optimum temperature for the developing process. The tempering device (48) comprises at least one Peltier element (52) which has at least one of its two tempering faces thermally connected with treatment liquid. The Peltier element (52) is adapted to receive a reversible supply voltage whose amount and polarity can be controlled. Depending on the polarity of the supply voltage, the Peltier element (52) operates either as a heating element or a cooling element.

Abstract: In the method for controlling the temperature of an intermittently standing and flowing fluid which is at rest during standstill intervals and is flowing during flow intervals, a desired temperature for the fluid is predetermined and the actual temperature of the fluid is measured. The fluid is heated and/or cooled by a tempering device, depending on whether the actual temperature is higher or lower than the desired temperature. The tempering device is controlled by a control unit with at least one variable and self-adjusting control parameter. In the method, it is detected whether the fluid is presently at a standstill or in flow. The value of the control parameter of the control unit valid at the end of a flow interval is stored and at the beginning of the next flow interval is set as the current control parameter in the control unit.