Digital BW, The Print

Sorry for 2nd post- 1st appears to have disappeared in c-space.
I just purchased an HP 7960 hoping to get the excellent results of
other forum members.
The first print "out of the chute" had 3 clearcut sets of linear
markings on the surface, visible when print held parallel to floor and
viewing at 45 degrees. Viewing perpendicular to the print, they cannot
be seen. I don't feel this is acceptable in an semi-archival printer
as the surface damage (HP Premium Plus 11.5 mm paper) may be apparent
in several years when viewed normally. 
 Does this mean the printer is defective ? Do the tracks go away after
10 or so prints ?

                        Stuart