Solved.
I removed the printer again from my printers list and re-added it. But instead of adding it as «Standard» printer, I choose «IP», typed the pritnters address manually and used the LPD-Protocol. This worked - didn't extensively test it with different Apps but on the first few tries the Apps that crashed before, did crash no more and the printer startet printing also alot quicker than before. Seems to be a network protocoll issue...