nothing i can do.
i have no power about how emails work (and what your hardware does with it)
another option would be to send a second separate email to the printer only
see here for a starting point
https://support.wp-pizza.com/topic/after-every-order/
in a future update to the plugin, there will be the possibility to send several independent emails/orders and layout to different recipients, but it will be a few weeks yet until i have this implemented and tested