1) Did you make regular cleaning? 2) Sensor is not working properly(maybe a replacement of spare part is needed). 3) Maybe you just connected your usb cable to another port and it generated a copy, in that case, delete all printer Evolis drivers from control panel and enable it from beginning again.
Answers & Comments
You have 3 possible problems/solutions:
1) Did you make regular cleaning?
2) Sensor is not working properly(maybe a replacement of spare part is needed).
3) Maybe you just connected your usb cable to another port and it generated a copy, in that case, delete all printer Evolis drivers from control panel and enable it from beginning again.