The most common use for an A3 printer (Large Format Espon Printer) is in printing labels. For this reason, very few people have actually used or seen A3 printers. This is an article that gives you a little information about the A3 printer.
There are two basic options for using an A3 printer. Direct thermal and thermal transfer. The difference is in how the design is printed onto the label material. This means that there are different operating procedures for each one as well as specific requirements the material it will print on must comply with. If these specifications are not met it is possible that sufficient damage could be done to the print head over time to require that it be replaced earlier than it should have to be.
If you are going to b doing direct thermal printing then the following should be noted:
The surface coating of the material being printed on must sufficiently cover the heat activated coating to make sure that the printer head does not get damaged in the printing process. If the coating is too thin the printer head may be exposed to small explosions that result from the chemical reaction triggered by the heat. This may cause pitting and the print head is quickly damaged to a point where it can no longer be used and has to be replaced.
The surface of the material should be smooth to avoid abrading the printer head.
Also look for material which requires the lowest heat possible. The constant cooling and heating of the print head may compromise it. It can also have an effect on the quality of the printed material if too high a heat is required as the print may smudge if it is not left to cool down sufficiently before being moved and touched.
As far as thermal transfer printing is concerned, the material that is best will depend on what you intend to print and the A3 printer you are using. You can ask the manufacturer of your specific machine what specifications this mode of use requires before you go ahead and do any printing on it.