How can you print full bleed on a sprocket?

@Trh2017
 
This is a great location to get assistance! I read your post and see that you are getting print quality issue on HP Sprocket. I would like to help you resolve this issue. 
 
Clean the output rollers with the blue HP ZINK® Smartsheet from the same pack of photo paper currently in the printer.
Update the printer firmware.
On your mobile device, make sure it is connected to the Internet, and then open the HP Sprocket app. If there is a firmware update available, a firmware update screen displays. Follow the on-screen prompts to complete the update.
Make sure images have a minimum resolution of 818 × 1258 pixels per inch (ppi) for optimal print quality.
Use genuine HP ZINK® Sticky-Backed Photo Paper.
Click here and refer the document for more steps.
 
Let me how it goes.
Cheers.