staff lines problem in professional printing

[Fodor Bertalan]

I think this problem has been on the list years ago, but it seems to be
present now, too.
I have just had printed a musical piece with a professional PostScript film
imagesetter (Heidelberg Primesetter) in 2540 dpi. 
The staff lines are much longer than appropriate, so it is ugly when printed
with that typesetter machine. It is not so visible in Ghostview nor in
Acrobat, but I scanned it to be able to show.
Please look at http://www.inf.bme.hu/~berti/lilypond/problem

(Note: this fragment has been made with lilypond-book, v2.1.26).

Thanks,

Bert