We have scoured the web for the most unusual, random and downright fascinating printing-related articles out there. We start with a playful look at the more frivolous side of ink innovation and swiftly move on to some industry advances that could make a real difference to the environment. Next, we explore how printing is being applied to microelectronics and finish off with a look at a printing application that could change the lives of millions of people in the most dramatic of ways. Who said printing’s boring?

1. Edible Ink

Not a lot of people know this, but if you take a photograph down to the bakery section of your local supermarket, they’ll print it onto a birthday cake for you. They don’t use traditional printer ink because it’s poisonous, not unlike some of the other artificial additives and flavourings found in a supermarket birthday cake. They use edible ink, which is non-toxic, but definitely does not count towards your 5-a-day!

The Californian company Kopykake have created edible ink cartridges (the ink’s edible, not the cartridge) that can be used in your home Canon or Epson printer. For the non-paper eaters amongst us, they also sell edible Frosting Sheets to print onto. Kopykake’s edible ink cartridges will not clog your printer heads and what’s more, they’re certified as Kosher.

2. DNA Ink

Great writers never really die; they live on forever in their work. Mr Yoshida, President of Tokyo’s Ko-sin Printing, has taken this idea to the next level. He has created a new type of ink that contains the author’s genetic footprint, providing an altogether less disturbing alternative to penning a love letter in one’s own blood. DNA is extracted painlessly from a human (or animal) hair or nail, and then mixed with ordinary ink to create DNA-enriched ink: the ultimate in vanity press.

The DNA doesn’t alter the ink’s appearance, but through scientific analysis it’s possible to extract genetic information from any material printed in this way. DNA-enriched ink has already been used to add a personal touch to several self-published autobiographies. Perhaps in the future, this technology could be used to authenticate genuine works of art, or even store the genetic makeup of endangered species in books and leaflets, so that one day they can be resurrected, post extinction, a la Jurassic Park. Or perhaps, that’s a little too far-fetched!

3. Disappearing Ink

The Palo Alto Research Center (PARC) created the PC, inkjet printing, Ethernet networking and the mouse, only to have these creations ‘stolen’ by other companies. PARC has now developed a new product, ‘disappearing ink‘, which it believes will prove just as revolutionary. Let’s hope they can take all of the credit this time.

Disappearing ink is something of a misnomer: there’s actually no ink involved in the process. Instead, paper is coated with photosensitive chemicals that darken when exposed to UV light produced by a special printer. Whatever is printed onto the page fades away after 24 hours. If the paper needs to be re-used more quickly, the printer can erase the paper’s image instantly. This photosensitive paper can be used an infinite number of times, so long as it doesn’t become crumpled or torn, saving energy, money and the environment in the process.

4. Eco Ink

The Big Print, a printing company in Seattle, have become one of the first to trial a new eco friendly type of ink that, unlike traditional petroleum-based inks, is both renewable and biodegradable. This ‘eco ink‘ is made from ethyl lactate, which is derived from corn, a renewable resource that is available in abundance in the USA.

The large format printing industry creates massive amounts of waste. The Big Print alone produce 1 million square feet of material each year. The use of eco friendly ink is a huge step towards making the industry more sustainable and environmentally friendly. The Big Print, which currently uses the corn-based ink in 10% of their printed output, maintains that its use does not affect print quality. Despite it being more expensive at present, they are investing in new machinery so that they can use even more of the ink in the near future.

5. Nanoink

Californian company, Nanosolar, make solar cells: devices that convert sunlight directly into electricity. They are currently building the world’s largest solar cell factory in San Jose, which covers an area of 140,000 square feet. They have created an ingenious type of ink that makes it possible to print the CIGS (copper indium gallium selenide) semiconductor of a high-performance solar cell, making mass production quicker and easier.

The nanoink contains the CIGS semiconductor material, which consists of four elements in exactly the right atomic ratios. The mix of nanoparticles in the ink locks in these ratios so that they are correct, wherever the ink is deposited. Rolls of semi-conductors can be printed at a time onto a metal foil substrate.

6. Silver Nanoparticle Ink

A research team at the University of Illinois have developed a new type of silver-based ink, made from silver nanoparticles, which can be used to create microelectrodes that carry signals between circuit elements. These unique printed microelectrodes can be stretched and bent repeatedly with little change in their electrical properties. The university team has managed to print silver microelectrodes with minimum widths of just 2 microns.

To produce printed features, the team uses a highly concentrated silver ink that’s forced out through a tapered cylindrical nozzle attached to a micropositioning stage. The ink’s bonded by being heated to a temperature of 150°C, low enough for flexible, organic substrates to be used. Because the process uses minimal contact pressure, it can bond silver features onto extremely delicate devices.

7. Gold ‘Fountain Pen’ Ink

A Swiss-US research team has devised a method, known as the ‘fountain pen‘, for depositing gold nanoparticle ink stripes as thin as 5 microns. The stripes are solidified by illumination with an argon laser. Fascinatingly, the stripes’ elctrical properties can be customised by changing the laser’s power and scanning speed, providing an exciting new way of creating miniature resistors and conductive tracks for flexible electronics. At present, inkjet printing can create stripes no thinner than 50 microns.

The ‘fountain pen’ is a pulled glass pipette that’s placed 2 microns above a glass substrate. The ink inside contains gold particles (2-4 nm in diameter) in toluene, a clear, water-insoluble liquid. The laser is beamed from underneath the substrate, directly below the pipette, onto the newly printed structure.

8. Bio Ink

Researchers at Carnegie Mellon University in Pennsylvania have used a type of inkjet printer to simultaneously grow different tissues from the stem cells of mice. The inkjet device shoots various ‘bio ink‘ patterns of growth factor proteins onto stem cells. By using different print heads and patterns, the stem cells can be directed to become different types of tissues.

The team has already managed to grow muscle and bone in the same dish, the first time more than one type of tissue has been grown from a single population of stem cells. They are now investigating ‘bio ink’ patterns that will grow other tissues found in the human body.

The researchers hope that this technology can one-day be used to repair various tissues at the same time. This will be of particular benefit to those who suffer from joint problems and other conditions that damage cartilage, bone, muscle and fat simultaneously.