pyusb backend failes after multiple runs for QL-570

[arbu]

If I run a program multiple times that uses the pyusb backend, the printer stops responding to commands usually the second or third time. I was able to trace the problem to the call to self.dev.set_configuration(). If I remove that line or if i prepend it with a call to self.dev.reset() it resolves the issue for me. I'm not sure thou, what the implications of either of it are for other models as I only have this printer. Another option I could think of would be to check weather the default configuration is already set.

[mkke]

I see similar behavior with a QL-800, and removing the set_configuration fixes it for me, too.