Patent ID: 8083716

Claim:
A plunger head moveable within a reservoir to expel fluidic media from an interior volume of the reservoir, the plunger head comprising: a plunger head body having a front end and a rear end opposite the front end, the front end of the plunger head body defining an end of a front portion of the interior volume, the rear end of the plunger head body defining an end of a rear portion of the interior volume, the front end of the plunger head body having a concavity for trapping air bubbles in the fluidic media as the fluidic media is expelled from the reservoir by the plunger head, the front end of the plunger head body defining a wall around the concavity; and a seal member arranged along a side surface of the plunger head body that is substantially parallel with an inner surface of the reservoir to engage the inner surface of the reservoir, the seal member arranged at a location on the side surface that is spaced apart from the front end of the plunger head body; wherein the wall of the plunger head body is spaced apart from the inner surface of the reservoir as the fluidic media is expelled from the reservoir by the plunger head; and wherein the plunger head body and the seal member are arranged in the reservoir to prevent fluidic media from passing between the rear portion of the interior volume and the front portion of the interior volume.