Splits printer didn't work at fundraiser. It produced paper but they were blank.

I have solved this by turning the paper roll over! The paper is thermal on one side only. I had taken the roll out to measure it to purchase replacements and had placed it back the other way round. I mention it here in case it happens again. I raised the issue with a few 'knowledgeable types' at the event but none of them suggested turning the roll over!