When will the public key of an address used in the network?
The 1111111111111111111114oLvT2 hasn't been spent yet whereas 1HBheYzvX7NDtcwVrMS7gxReNRVezYS7w2 has.

To spend, the public key is part of the INPUT's ScriptSig:


http://en.bitcoin.it/wiki/Transactions#Explanation


So until there is a spend transaction, the public key isn't known to the network, just the Bitcoin address.

Related: Why is it impossible to derive public key from address?