Samurai worn armors but these armors were not as same as the armors worn by the knights. Knight's armor was usually more than 10 kg but samurai's armor has to be lighter than the knight's.
However samurai wore the armor only during a battle against enemy's army. Which means if they had to fight one on one, samurai did not wear the armor at all.
Usually armors were almost the same among samurai but the famous samurai(commanders) had their own unique helmets which can be easily recognized by both allies and the enemies. These commanders never tried to hide behind the front lines but rather encouraged his soldiers.