The Epson DS-510 (and now DS-560 since version 0.9.9) is one of the auto feeder scanners that is supported by Kronocard.
On the pros side it is fast and half the price of the Fujitsu fi-7160 but on the cons side it is less precise with borders and may have a difficult time to grab some cards. This lead to images that are looking stretched.
One thing you can do is to place your cards in landscape orientation, as shown in those pictures:
It will be easier for the Epson scanner to grab your cards this way. Please note that with the Fujitsu the portrait mode works better.