Ink-jet Technology

In contrast, drop-on-demand technology ejects ink only when required. Your home office ink-jet printer is most likely to be a thermal drop-on-demand system. Tiny resistors heat the ink causing it to vaporise creating a bubble that expands and pushes some of the ink out of a nozzle (hence Canon's trademark "bubble-jet"). For industrial uses, the piezo-electric drop-on-demand method is preferred. An electric current is used to vibrate a piezo-electric crystal. Each vibration forces a tiny amount of ink out of the nozzle and then pulls some more in to replace it. This method is of particular interest for applications like circuit board manufacturing because it does not create steam or vapour that might disrupt the chemistry of the ink used.

Tissue engineering

Taking care of the ink-like substance is of particular importance to researchers at Manchester University who are using ink-jet technology for tissue engineering: the development of replacements for biological tissues. Specifically, they have been evolving ink-jet technology to print 3D structures that recreate the different layers and properties of skin tissue.

Tests show that despite effectively being hurled at a brick wall, living skin cells have a 98% survival rate as the ink in an ink-jet printer! The cells are fired onto a bio-degradable scaffold made from a sort of plastic. This cell structure is then sprayed with nutrients that encourage the DNA in cells to multiply and join together. Over time, the scaffold dissolves away leaving a realistic skin that could help heal burns.

The advantage of using ink-jet technology is that different types of cells can be placed in different layers to best mimic real skin tissue so that it has the best chance of being accepted by the patient. Other "spray-on skin" methods tend to involve taking a piece of unaffected skin from a patient, either stretching it out to form a scaffold, or chopping it into little pieces and then spraying the modified tissue with skin cells.

But research into alternative uses of ink-jet technology is still in its early stages. The challenges include understanding the chemistry of the ink substances used, its interaction with the printer and the physics of predicting where the droplets will land. If all this can be grappled with, the applications seem to be limited only by our imaginations…

For more information:

Physics Web - Ink-jet technology moves beyond paper
http://physicsweb.org/articles/world/19/1/4

PC World - Your Old Inkjet Printer Could Aid Burn Victims
http://www.pcworld.com/article/id,118815-page,1/article.html