I'm thinking 80s too with those colors. Honestly - I've never heard of the name before (I live in Switzerland), so I couldn't say if this was an important designer or company. I found a German news article from 2003 that said the company was sold to an Italian textile producer. And there's an article from 1999 from a textile industry journal that talks about their then new collection, which was produced in Osnabrück where the company was located then. It talks about a new, "younger" line they produced under a different name, whilst their original "Erica Rössler" collection traditionally was more classic. It also mentions a men's line called "H.P. Rössler". It's not clear if there ever was an actual designer or perhaps company founder called Erica Rössler or if that was just invented as a brand name. They still seem to produce knit wares and I see a few German mail order companies carry the brand.
