there's two and more possible solutions to do this:
1) Base the tap spawning on a grid. For example if your tap sprite is 32x32 pixels, than this is the minimum distance between to taps.
2) Upon spawning a tap, check the distance of it to each other tap. With a for each loop, you can check distance (x1,y1,x2,y2) > 32. If true, proceed with the spawn. Else, reiterate.
Solution 1) is more elegant with the downside of having a fixed grid. Solution 2) lets you keep completely random positions at the cost of some calculation time.