Do any engine manufacturers past or present have anti icing capability for the N1 disc? Seems to me heating them by some means would rob the engine of further by robbing more bleed and potentially raising the air temp.
I think I understand what you asked in the first sentence, although I don't understand what you are saying in the second.
I've never heard of any means to plumb hot air to a fan
blade. Not sure of why you mention a disc in your question.
The technical challenge is overwheming to prevent ice formation anywhere in the inlet fan flow environment simply due to the heat transfer/loads necessary to overcome. The current technology seeks to only limit the amount of ice build up to a point where safety of flight is not threatened. Thus, the plan is to have the ice shed itself after it builds up in small enough layers to be shed without causing problems. If the buildup is anywhere near the centerline of the engine one can always plan on some heat being driven forward up the drive shafts from the turbine area. Even a few degrees warmer can help limit the ice buildup on a fan spinner.
But for the fan blades we're just going to have to rely on mother nature and newtonian physics for the present.