No – you can’t print directly onto clamshell HID cards because of the material type and the thickness of the card. However, you can print onto self-adhesive white cards that can be stuck directly onto the clamshell card.
Alternatively, you can replace your clamshell-style cards with HID Isoprox cards which can be printed on with a retransfer printer.
IMPORTANT: Do not attempt to print onto HID cards with a direct-to-card printer: it will damage the print head.