We have found a stock of HP original thermal printer paper. It is valid for all HP thermal printers, from the HP-91 to HP-97, going through the diverse HP-41 familyy (the IL printer and the 82143a printer), and finally, the current HP82240a/b infrared printers.
You would not believe the difference it makes over the original blue thermal paper that came with most of the above printers, except the last ones. There is much more contrast. What you accepted as good printout will not be acceptable from now on.
We have been told as well that the prints last much more than the original rolls. This is an additional advantage for those that want to keep record of their calculations together with their job.
You can find it here.