I tried with several applications like LibreOffice. I tried with the function "print test page" directly from cups admin. What is strange is that cups indicates that jobs are completed.
If I try the function "Clean Print Heads" , I have got the mesage "Invalid printer command "Clean". The only error I have got in the cups log : W [04/Dec/2017:09:01:37 +0100] CreateProfile failed: org.freedesktop.ColorManager.AlreadyExists:profile id \'QL-570-Gray..\' already exists -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1735991 Title: QL-570 printer : the led flashes red and nothing happens To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ptouch-driver/+bug/1735991/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs