Just for a change, I punched a new-old-stock Inmac pen from its sealed blister pack, only to find that it left a spotty trail. These being easy to refill, I popped the top, flipped the fiber reservoir, added ten drops of HP2000C black (i.e., not the crappiest ink I’ve ever used), and scribbled a few feet to get it started again. It left a good-enough trace, so I ran an A-size plot with the ball pen, two liquid ink pens, and a refilled ceramic pen:
It’s a bit pallid compared with the black ceramic pen. The line is continuous and, in comparison with all the other plotter pens in the collection, very very very fine.
Turns out that it’s a miniature ball-point pen:
I’m certain that water-based inkjet juice isn’t the right stuff for a ball-point pen, which may account for the lack of color. It’d be most appropriate for a document with fine text details, not that I must plot any of those at the moment.
There’s a bag with a dozen more of ’em in various cheerful colors, so, if I could just think of something that needed stubby ballpoint pens, I’d be all set.
It might be intended for a different HP plotter that applies more downforce to give the ball more encouragement. We’ll never know…