Work on the RGB Pen

I'm logging some work I did a few years back, thinking about how it would be possible to do an RGB Pen, Idea #126. The RGB Pen is like a regular pen, but it has three ink cartridges (Red, Blue and Green) so that the ink can be mixed and the pen color can be customized. This is all strictly a though experiment of sorts, none of this, as usual, was ever built. 

The first design is very simple, basically a screw presses the ink flow, constraining it:

The second design is much more involved:

A ferromagnetic ball is placed, a little loose, blocking the way out of the ink from three ink flows. A screw with a magnet on the tip can displace the ferromagnetic ball, enabling more or less flow to pass, altering the proportion of inks. This screw can also be made parallel to the pen surface, but it wouldn't be so clear in the drawing. Finally a segment on the tip enables the ink to mix before exiting the pen. 

The third design is purely conceptual:

It describes a pen with a single ink cartridge, and a "changer". This changer is something that can affect the ink, for example change the temperature or the pH, so that the ink change its color. It relies on the chemical properties of the ink itself. 

BANNER IMAGE CREDITS: N/A. The image has been cropped and resized, and added to a black background.

Want to know more about this image? Follow this external link.