Estou com o mesmo problema. Você pode usar drivers Seagull.
Solution: Use the Seagull Drivers and turn dithering off.
The seagull drivers are much easier and straightforward while having all of the printer options set-able.Configuration:
1: Download and Install the Seagull Driver Package:
http://www.seagullscientific.com/drivers/printer-driver-features?m=zebra+lp284411
2: Setup your custom paper stocks for easy selection in drop-down of print dialog
I Use 4 x 6 for shipping labels and 1.25 x 2.25 for FBA labels (Amazon also uses 1.25 x 2.25 labels in their warehouses)
3: Turn Dithering Off
4: Set Darkness to Max
5: Set Speed to 1.5" or lowest tollerableBAMMM! you can now print direct from the chrome print dialog by setting the following in the chorme dialog:
1: Select Paper Stock from your custom stock setup in the print driver
2: Turn margins off
Fonte: link