Is the cap on (non-retractable) ballpoint pens necessary to prevent the ink from drying out, or is it just there so that you won’t get ink on your shirt when you put the pen in your pocket?
I have always been very scrupulous (or as my wife says - obsessive) about putting the cap back on ballpoint pens to keep the ink from “drying out”. I think I got this habit from my mother. However, today when discussing it with a colleague, several points came up that made me think I might have been mistaken all these years.
[ul]
[li]My colleague says that the “ballpoint” in a ballpoint pen actually serves as a “cap” that prevents the ink from drying out.[/li][li]Retractable pens obviously don’t have a cap, therefore a cap isn’t necessary.[/li][li]The non-retractable pens that are standard issue in my office (PaperMate FlexGrip Ultra) have a hole in the cap! And so do some of the Bic pens I think. Which means that obviously contact with the atmosphere is not an issue.[/li][/ul]
This may be an urban legend, but I’ve heard that the hole in the cap was put there so small children can’t choke on it if it’s swallowed.
I’ve picked up ballpoint pens left out for years, with no cap, and they started writing almost immediately, so it doesn’t seem like any anti-drying mechanism is needed.
Don’t forget the small hole in the side of the many ballpoint pens, near the top. In addition, I’ve used many pens with the top cover removed (that plug that pushes into the top of the pen. You’d think that would be the place to stop ink from drying, since the top of the ink column is sitting near there, with no cover.
We really need some good names for these parts of the pen!
After all, some ballpoint pens have no cap at all. Rather, they retract into the body of the pen. This leaves the ballpoint very close to the opening, and the atmosphere. Also, I am very lazy about replacing the caps, and it never seems to hurt the pen, even after long periods of er… caplessness.
Nope, not an urban legend. There were cases of young children swallowing the caps and chokeing. (And some not so young!). It is now required in many countries that there be a hole in the cap that air can pass through. But the hole doesn’t have to be through the protective tip of the cap, it can, for instance, be parallel to the bit the ball point goes in. Think of the letter g, the ball point goes in the circular part of the letter, the air tube through the stem.
My bet is that the caps, or retractable tips, are to protect a shirt. Don’t know if it still happens, 'cos I haven’t used a ball-point in years, but some used to get ink encrustations around the tip.
Ballpoints are the most popular writing mode because they suit all writing styles. A good ball pen writes smoothly without skipping on most surfaces, even glossy or coated paper. They have a thick paste ink that is long-lasting and does not dry out when the point is exposed, which is why most ballpoint pens do not have caps. The points are exposed by either a push-top or twist mechanism.
D18, you must have me mixed up with one of the smart moderators.
I did a Google search actually, and I found a page (of course can’t find it again) where one pen manufacturer was bragging that “this retractable pen will not dry out even if you leave the point exposed!” So that would seem to imply that some other pens do? Though of course the pen in question might have been a “rollerball” - another site mentioned how ballpoint pens don’t dry out but rollerballs do. Of course, any information you find on the internet must be taken with a grain of salt. I found several pages that were “word-for-word” identical, so it looks like someone finds an article they like and copies it to their site. If one mistake is stated authoritatively enough, it could end up in hundreds of HTML documents.
By the way, here’s How Stuff Works : Ballpoint Pens
“How Stuff works” does mention that the ball in the point acts as a cap and prevents the ink from drying.
What seems funny to me is that if the ink doesn’t dry out while in the pen, why does it dry out so quickly when it’s on the paper? Is it a chemical reaction with the paper (doesn’t seem likely since you can write on your arm or other materials), or is it because the ink is spread out in such a thin layer on the writing surface?
My guess is that the ink does, in fact, dry out on the tip of the pen, but the ball is so small that it only takes a very small roll to recharge it with fresh ink.
I very much remember first noticing the caps with holes, in the early to mid '90s. The only real logical reason is to be able to breathe through it long enough to have a doctor remove it.
Imply, yup, that’s the word for it.
It doesn’t mean that the others dry out, it’s meant to make you think they do. That’s advertising.
I believe, that the reason for the cap is to protect your clothing. The ink will not flow on it’s own, but when the ballpoint makes contact with the fuzzy little fibers in the bottom of your pocket, the ink is drawn out via capillary action.
I like to use pen caps to keep the pens from being clogged by dust and oil.
Down in the dark, cavernous, tomb of my brief case, pens face all sorts of nasties. Those which keep their caps on always write. Those that don’t often take a while to get writing again, or permanently block up. The same models in my desk drawer, which is clean and in which the pens do not have their points pushing into anything, almost always work regardless of whether or not they have caps.
Muffin makes a good point – the cap (or retraction) also helps keep the ball point from getting fouled up with lint or dust.
The “classic” metal-ball-point ink is a sticky oil-based goop, as opposed to the runny water-based wash on “rollerball” pens, so an uncovered ballpen would eventually gather a lot of lint around the tip (and for decades they were prone to leaking messy gobs o’ the goop around the ball, too).
BTW the “side” hole on the barrel of Bic/Biro-type ballpoints (hidden into the top of the barrel in PaperMate “Write Bros” ballpoints) may be to equalize pressure for all I know… What I do know is that these used to “blow up” on me every so often – what a mess!
