Printing on today’s athletic garments can be a daunting task with so many different variables to consider. One big one is ink types.
You want an ink designed for lower oven temperatures—preferably somewhere around 280 degrees F. You also need an ink that has a fast flash, as that helps to reduce the temperature under flash elements. Just because the ink has a low cure temperature does not mean it is suitable for all fabric types. A low-bleed, low-temperature ink may be perfect for tri-blends, but may not have enough bleed blocking characteristics and wash fastness for polyester printing.
For polyester printing, you want a low-temperature ink designed for polyester. For dye-sublimated products, as well as some poorly-dyed polyesters and blends, it may require a gray or black die-blocker underbase to prevent dye migration in conjunction with the low-temperature polyester ink.
Printers can also print on polyester garments with a high solids acrylic water-based ink. You must adhere to all the above, as well as use a carbon dye-blocking underbase, not just on dye-sublimated fabrics. Due to the thin ink film of water-based inks, it cannot block dyes by itself, even when using a low-cure additive. The temperature of your oven is also critical with water-based inks because they are in the heat chamber longer than plastisol inks. Therefore, there is more opportunity to reach temperatures above 280 degrees F, as thin polyester shirts heat up quickly.
The last ink for polyester garments is silicone ink. Silicone is very advantageous to print with because it cures at lower temperatures, and dye migration goes right through it. This means the final product doesn't show any dye migration. Using silicone ink can be tricky because you must catalyze silicone ink as it cannot adhere to polyester garments by itself. Once catalyzed, most silicone inks are only usable for three to four hours, so you must finish before the ink begins to catalyze on its own. Techniques and improvements for silicone ink can give you longer print time. However, due to the expense of silicone ink and the fact that the process is different than plastisol, it has not proven itself a viable option for most printers.
To get more help on controlling the process and temperature, check out Aaron Blank's full-length article on printing athletic apparel.