I came across the issue with legend printing with ArcGIS for Server Printing service. If I use higher DPI values (e. g. 200 DPI), I'll get pixelated symbols in legend (please see image below, where on the left side is legend and on the right part of the map).
But it is registered for version 10.1 and my server is 10.22 and the output is not PDF but PNG.
I've tried the workaround described in the arcticle (changing the page size for arcgis server account) but it hadn't helped. Maybe it is because the only printer installed on server is Microsoft XPS Document Writer?
Thank you for help!