The color image forming apparatus comprises a transfer belt device which feeds a transfer member such as a paper and a plurality of image forming units. The apparatus has a measuring device which can be moved, at least in the transport direction of the printing materials. An interoperability server receives the scenario identifier and accesses interoperability data to obtain the connection information corresponding the scenario matching the scenario identifier. An almost vertical second coolant flow passes between the IR emitters and the at least one back reflector, this second coolant flow being at least partially fed by the almost horizontal first coolant flow andor is united with the almost horizontal first coolant flow.