First of all, the print function is required for all of ecommerce platform and magento already supported it. But Magento only support print invoice or shipment, what we need to do is printing a order. In many situations our customer will need to know the detail of order before they pay.
In this article, I will show you a very simple solution to print order in magento with small extension
FREE DOWNLOAD: https://app.box.com/s/87174yvvvk7vorugfjjz
All you need is upload and install it to your magento site and then clear cache, log out and log in again, you will see the print button in order detail page.
Thanks and welcome any comment.