Ring Flash
There are basically two kinds of ring flash: those designed for macro (closeup) photography and those designed for facial photography (as in cover models). The reason one would use ring flash in either case is that it's flat, one dimensional lighting.
Pens are very multi dimensional, in addition to have nice shiny parts to reflect some of that light you aim at them.
The best pen photography is the best product photography: put the pen in a white tent and focus your lights on the sides or top of the tent. If you have multiple lights, move one of them further from the tent than any of the others to bring out the "roundness" of your pen.
Regards,
t.