I am looking for recommendations for ink types and brands to use for flexible printed electronics using a commercial printer (Epson, Canon or other with external ink tanks). Please give me your suggestions. Thank you
I cannot give direct brand names for inks as I had synthesized my own electronic ink.
But I can give you some parameters to look for in order to guide you.
I had used commercial printer to deposit thin conductive traces. There are certain things to watch out for when using commercial systems.
1. Particulate or solution based inks: Almost all commercial inkjet printers have at least one filter before the printhead. Some of them are found inside the cartridge. Others may have a second filter just before nozzle cavity. If you are using an ink with conductive particles, you must make sure your particles are less than a micrometer wide in at least one of its dimensions. Otherwise, your printing process may be interrupted due to clogging. Or you may find yourself going through cartridges/printers often. If you use a solution based ink, such as organo-metallic inks, you won't need to worry about particle size.
2. Surface tension and Viscosity: Many inkjet printers are designed for water based inks. You need to check up on this based on individual models. On the other hand, depositing traces on a non-absorbing surface often requires adjustment of ink surface tension. If your surface tension is too low, you will observe ink leakage from nozzle, even when not printing. Rule thumb says do not go below 30 mN/m surface tension for your ink. But I have seen inks leaking out even for values a bit higher than that.
You also need to have control on viscosity. If you have particulate ink, such as metal nanoparticle inks, you will usually have low viscosity. This will not cause any immediate issues for printing. But, if you are using conductive polymer inks, they usually have higher viscosity values than water. High viscosity may cause satellite drops to form during jetting and cause misplaced patches of film.
3. Finally, choice of chemicals. These days commercial printers are made from cheap plastics that do not agree with a lot of common solvents. Whatever ink you put into your printer, you need to make sure its components will not destroy plastic/metal parts. Solvent attack may cause plastic pieces to swell. Its chemical components will go into your ink and end up in your film. This may not be a huge issue but it could mess up with your data. Solvents may also destroy adhesives companies use when manufacturing printers. This will not only destroy printer components but also have adhesive chemicals ending up in your films.
This has got pretty long of an answer, but these simple point may be enough to guide at choosing a proper ink for your purposes