All printers used for heat transfers are standard, off-the-shelf printers. There is nothing special (modified) about any of them. Most of them (despite manufacturer's claims) print just as good as any other printer for heat transfer needs.
A potential problem is in the regular inks that come with these printers. The reason for this is because so many printers use a type of regular ink that is very water soluble and therefore washes out very easily.
However, some inks give acceptable results, not great, but acceptable. All inks come in two different types, Dye-based and Pigment based.
Dye based Inks - This type of ink is made from dyes (as the name implies) and was designed to make photo prints more vibrant. Older dye-based inks were not very good and most were water soluble which was terrible for use as transfer inks. Dye based inks nowadays are much better but you should test your printers ink (including washing) before trusting them.
Another myth is the thought that no dye based ink washes good and that all pigment inks do. Wrong! Bad ink is bad ink. Good ink is good ink. Dye based inks today may work just fine, just test it to be sure.
Pigment Based Inks - Pigment inks are solid particles in a liquid suspension. The pigment inks in the Epson 1900 was a good example. However, do not assume that all pigment inks produce good, washable heat transfers.
Pigment inks have a tendency to be pastel in appearance with blacks that look more like a very dark gray with no special washing instructions required. Some pigment inks can even change color slightly when heated.
Note: There is about a 5% color loss on the first wash, with any of our inks. Even pros consider this to be very acceptable. The important thing is that there is very little color loss after that.
About Inkjet Cartridges
If your planning on using standard ink cartridges in any printer be aware of the cost per print. Standard ink cartridges can print between 20 to 30 8" x 10" full color prints. Simple math can tell you the cost per print, price of the set of cartridges divided by the amount of prints you get.
For example, a set of cartridges for most printers is $40. The cost per print would be around $1.33 if you can get 30 prints out of them.
Our conclusions: If you own an inkjet printer, and want to use it, then the only smart thing to do is to test the ink that is in your printer. Print a transfer with it, heat transfer it to a shirt and then wash it. This ain't rocket science, so just see what your eyes tell you. If the results don't please you, they certainly won't please your customers.