Fusing temperature control

Question

Dear Sir, I'm using now Dialta Minolta Di250 everytime i do 2 sided or ( back to back ) printing the machine does not work properly always stock up on the second page coz paper curl after fusing section. On the other part if i copy only 1 side copier work properly. On my observation fusing temperature is so high, please advice how to adjust fusing temperature. Your early response is highly appreciated.Best Regards,Giovanni