A lot of free CAD programs such as IMSI Doublecad will now read SketchUp files but you shouldn’t need to.
I do agree that printing in Sk2015 is a bit buggy. Dan’s suggestion to disable hardware acceleration is a good one. You might find as I did that switching it off and then back on surprisingly solves the issue. Also try unchecking ‘use model extents’. Again this solved a print bug that I previously had.
By the way is it printing to an actual printer that is the issue or to PDF? If it is the printer itself then double check the hardware settings and also you could try printing to PDF first and then printing it out.
More likely however it is your SketchUp print settings. In your print settings, set print quality to ‘Ultra High Definition’ for raster prints, or check ‘Use High Accuracy HLR’ for vector. The latter is the highest quality however textures and shadows won’t print as these are raster based. In addition within ‘Properties’ select ‘High Quality Print’.and under ‘Advanced’ you can also set the DPI (I use 1200). These settings should achieve a very high quality output.