I was always instructed the blade should not touch in thrust, mine doesn't, it works great. The Carter instructions (looking at the Carter page rendered by the link Ken provided) seem to indicate it should. Just trying to reconcile that discrepancy.
The Micro-Precision ball bearing rub block guide provides full contact with the blade for maximum accuracy.
My Centauro 800 (some Minimax have been Centauro models in the past) which uses what looks like the Carter CP20, says the following in the manual ...
The blade guide thrust wheel must never be adjusted in contact with the back of the blade, but at a distance of3+4 mm. If the blade is sharp and the feed force regular, it must not trip. On the contrary, the side wheels must skim over the blade, though without locking it, since they have the specific task of eliminating its vibrations, due to sawing. The wooden buffers of the bottom blade guide have to be adjusted using the same criteria.