Epson Stylus Pro 4000 Reference Manual page 148

Mode
Platen Gap
Eject Roller
Type
148
Printing with Mac OS 8.6 to 9.x
Description
Platen Gap is the height from the media loaded into the
printer to the print head. By adjusting this parameter, you
may produce better print quality. This is set automatically
according to the Paper Thickness specified.
Note:
Setting Platen Gap to Narrow may produce better print
quality, but make sure that the media does not wrinkle or
touch the print head. Otherwise, the printed data or the
print head surface may be damaged. Use Wider or
Widest in such case.
Select one that best fits your media.
Auto:
The printer selects the most appropriate setting
automatically. When you use Epson special media,
usually select this setting.
Starwheel-Sheet:
If you want to print on cut sheet which is non-Epson
special media, select this setting.
Starwheel-Roll Curled:
If you want to print on strongly curled roll paper which is
non-Epson special media, select this setting.
No Roller-Roll Normal:
If you want to print on roll paper which is non-Epson
special media, select this setting.