Printing problems

I have a plotter HP Design Jet 750C. When try to plot any drawings, have followings problems :- the texts (multiline text) are printed only as contour and with tremulous- the line with width below 1.mm are printed only to 0.25 mm.With the same driver, but using a OCE plotter, the problem don't appear.Could you please know everybody what is wrong?Regards,Liviu