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Anatomy of a rollerball pen


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#1 orion573

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Posted 12 June 2009 - 18:46

A question has been bothering me for a long time and I cannot find an answer for it anywhere online. I hope you can help. I realize it is not a fountain pen question, but rollerball is the compromise in writing instruments that works for me.

What is the purpose of the coils or rings on the Pilot Precise V5/V7 pens? Pilot calls the system "advanced ink feeding system" but I cannot figure out how it works or find the patent for it. If you have one of these pens you notice that when it is new, the coils are all clean. With use, ink starts to spread into the chamber and seems to be held back to be dried on the large surface area of the coils. What really bugs me are the spots of ink that appear on coils far away from the ink reservoir without any apparent path from the reservoir.

Also, what is the purpose of that whole clear section near the tip of the pen where the coils are found I realize the reservoir needs some kind of pressure equalization to keep writing and there appears to be a small notch on the outside of the chamber that might serve that purpose.

If you know these answers or have any hypotheses, please share

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Edited by orion573, 12 June 2009 - 18:50.


#2 zedcorrado

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Posted 12 June 2009 - 19:41

I have often wondered the same since it is one of the favored pens in our office.

#3 someonesdad

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Posted 12 June 2009 - 21:01

I don't have one to play with, so I can't offer an opinion. It looks like the pen can be pulled apart, so an answer might be gotten more readily from a picture of a disassembled pen (as long as number five lets you rolleyes.gif ).

An easy experiment would be to machine off the detail and see if it changes the pen's behavior. If not, then your answer is probably "marketing".

#4 orion573

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Posted 12 June 2009 - 21:45

Someonesdad, who knows, you might be right about it just being marketing...

The pen is a unibody construction -- nothing can be pulled out. The ink feed system (the gray piece from the tip to the black body) seems to be forced in during manufacturing at high temperature, creating the seal between the coils in the clear chamber and the ink reservoir, producing a ridge on which the pen cap sits.

QUOTE (someonesdad @ Jun 12 2009, 02:01 PM) <{POST_SNAPBACK}>
I don't have one to play with, so I can't offer an opinion. It looks like the pen can be pulled apart, so an answer might be gotten more readily from a picture of a disassembled pen (as long as number five lets you rolleyes.gif ).

An easy experiment would be to machine off the detail and see if it changes the pen's behavior. If not, then your answer is probably "marketing".



#5 PigRatAndGoat

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Posted 12 June 2009 - 22:31

I believe those combs work in the exact same way as a fountain pen feed. Nothing ground breaking really. I guess it just ensures a steady flow of into to the writing tip. As for how, don't look at me.

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#6 effika

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Posted 13 June 2009 - 03:05

I really liked those pens but I found they would always leak on me!

#7 HenryLouis

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Posted 13 June 2009 - 03:10

QUOTE (effika @ Jun 12 2009, 11:05 PM) <{POST_SNAPBACK}>
I really liked those pens but I found they would always leak on me!


Agreed! Well it wasn't this exact model but similar pens would always break.
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#8 aircraft_electrician

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Posted 13 June 2009 - 15:56

I looks an awful lot like the collector in a Parker 51, shown in this demonstrator:



I could be wrong, but I think it's purpose was to catch ink expelled from the sac during altitude and temperature changes.
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#9 lovemy51

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Posted 13 June 2009 - 18:00

maybe i'm wrong, but, from the pic., it looks like the cartridge runs directly from top of the barrel to the tip of the roller ball. so, why it needs the so called collector, or ring, or whatever, is beyond me...!!!
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pleese, forgeeve my bad espelling!! Posted Image

#10 kittenjess

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Posted 14 June 2009 - 08:28

Ah, what a interesting question!

I was told by a rep at Mitsubishi Pencil (the owner of the uni-ball brand of pens everywhere other than the usa) that its a shared tech between most water based ink rollerball pens and as others have surmised, it does function as a fountain pens feed system works.

I guess the V rollerballs work in the same way, given how it looks

For the record, I almost never can get away with the V rollerballs as other people have said, they seem most temperamental, for drawing I do find uni-ball eye to be a excellent replacement however

#11 publius

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Posted 14 June 2009 - 17:44

I used to use them all the time with no problem, frequently for drawing purposes, but I bought a batch a while back which just leaked into the caps in the most ridiculous fashion. Every time I would get one out I would find it messy with ink, & wind up throwing it away.
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#12 Possum Hill

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    It's just ink. Get a grip.

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Posted 15 June 2009 - 22:40

I just bought a pack of Pilot V5 pens, pulled the feed of one out with a pair of pliers, dumped the ink , put some Noodler's Hunter Green in the barrel and re-inserted the feed. It writes rather nicely, for a RB.
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#13 someonesdad

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Posted 15 June 2009 - 22:59

QUOTE (Possum Hill @ Jun 15 2009, 04:40 PM) <{POST_SNAPBACK}>
I just bought a pack of Pilot V5 pens, pulled the feed of one out with a pair of pliers, dumped the ink , put some Noodler's Hunter Green in the barrel and re-inserted the feed. It writes rather nicely, for a RB.

I've done the same with a Staedtler Liquid 7 roller ball pen and filled it with FPN brown. It also writes nicely.

If someone wants to PM me for an address and send me one of these pens, I'll do the experiment of machining off the feed's (if that's what it is) fins/comb/whatever and see how it writes.