Surveillance video shows the robber walking into a business on the 5400 block on North 5th Street around 11:45 p.m. Wednesday.
He then pulls out a handgun and robs a number of customers.
Police said one person fought back forcing the gunman out the door.
The suspect was able to fire a shot into the store, but no one was hurt.
He is described as a black male, 25 to 35 years old, thin build, with a beard, wearing a blue baseball hat, maroon hooded sweatshirt, blue and black shorts, and black and white sneakers.
Anyone with information should call police at 215-686-3353/3354.