How can I quickly/safely flatten photo prints that are curled due to printing from spool of paper?

I´m realy new at this forum. An other thread regarding curled print show some homemade products. It took me a while to find a construction similar to d-roller. Ive made it whith a softer plastic and different size at the metalpipe. It´s also very important that the ca 1mm tape/stripes are placed at both sides.

If you are interested in my solution I can send a picture. I can also send an exampel whith a low cost.