Self-adhesive #10 envelopes auto-feed quite nicely through Cartman, it turns out, so I'll be saving a lot of trouble on the program mailing by doing exactly that. But they ought to be going through at half speed (that is, 720 impressions per hour) and instead they are stalling. Stall recovery is only 20 seconds, so it's still faster than full speed on some printers I've had, but with 500 envelopes to print I'd rather not be at it for three hours. I think the problem is in the printer driver on my laptop; maybe separating the print into several smaller batches will help. I hope it's not that the driver thinks it's printing sideways, because I don't really have a plan for what to do about that.