HP 41/42 IR Printers

[CheshireChris]

I have the Swiss Micros HP-41X and HP-42S clones, both of which have an IR LED for printing to an HP thermal printer. A few questions:

1. Are there any modern printers that are compatible, or do I need a genuine HP printer?
2. If I need a genuine HP printer, which model number? I notice that there are two HP thermal printers, one ending in -A and the other -B. Is one the HP-IL and the other the IR printer?
3. Do the printers degrade with time like card readers do, or is an old printer likely to work?
4. Do they use a standard size thermal printer paper roll which is still available?

Thanks!