The following video shows how to replace the thermal paper roll of the ticket printer on the kiosk. 

Pay special attention to the position of the paper, as one side of the paper is thermal and the other is not. Therefore, if it is inserted upside down, the paper will come out blank every time it is printed. 

After finishing the paper roll replacement, perform a test print from the administration menu to verify that it is correctly positioned (https://helpdesk.roommatik.com/kb/faq.php?id=54).