Warranty Void if Removed

Thanks to Paul I just remembered another idea. Since the UV laser pulses are too slow for laser use (on further reading, 50% duty cycle is massively optimistic), use an inkjet printer. Have the output of the UV air laser connected to a fibre, and stick the other end of the fibre where the ink cartridge lives. Add some focusing optics on the end, and presto. 

Need to modulate the output of the laser according to the make-ink-go-now signal, and we're away.

So the next question is power density...

Say a UV box has two 8W tubes which shine over an A4 sheet for two minutes. Let's assume the tubes are 50% efficient, which they almost certainly aren't. So that's 8W of light over a 0.29m*0.21 m area ~ 131Wm^-2. Over two minutes the energy dissipated in the photoresist is about 120*131=16kJm^-2

Lets say our laser can put out 1mW. This is a conservative estimate, since some guy guesstimated his nitrogen TEA laser was putting out 200mW. Say we focus this down to a 20um (~1200dpi) diameter circle. That's a power density of  0.001 / (pi x (10 x 10^-6)²) = 3.2MWm^-2. So how fast does an inkjet scan? Lets say it does one line in half a second. So how long does it dwell on a pixel? Let's go for 1200dpi. That's a pixel size of 4.5x10^-10m². The laser spends 0.5/1200=400us over a pixel. 400x10^-6 x 3.2x10⁶ = 1.3kJm^-2

So it looks like a 1mW laser isn't powerful enough, but it's pretty close. 10-15mW would be better. However, it looks like this is doable with a nitrogen laser, 

Crap, one problem - I think inkjets print a row of dots with each sweep of the head. Perhaps old ones don't.