Hello JMcollection,
Inkjet heat transfers should be printed using pigmented inks. An example is the Durabrite inks for the Epson inkjet printers.
Be careful though, some of the older model Epson printers (the 1280 for example), uses a dye based ink and could run when washed. I have a 1280 and have used the stock 1280 ink with no problems but stopped using the 1280 quite a while ago as it was to big for my needs. I now use an Epson C86 with Durabrite inks with remarkable results.
It is my understanding that the newer Epson printers (the R series?), also uses pigmented inks and that people are making heat transfers with the stock ink for it. As I don't have the newer printer or much has been published about it, I really can't say much more.
Stick with pigmented inks. If you are unsure about the inks, you can try the 'wash test'. This is where you print your transfer, (be sure the ink is dry on the heat transfer paper), heat press it onto the shirts and then throw it in the wash in hot water. Before the final spin, pull the shirt out of the washer - while it's still dripping wet - and fold it into quarters. Let it sit an hour or twom be ing sure to keep it wet. When time has elapsed, unfold the shirt. There you will be able to see if the ink runs or it doesn't.
Hope this helps.
Fred