You can select the Output cells by the right hand side brackets and then double-click. This will temporarily hide the Input cell and you can then print the notebook.

As an alternative you can select the bracket of the Input cell and permanently close it by using Alt+C+P+O or using the Menu item Cell/Cell Properties/Open. (You can repeat this to toggle it open or closed.) Then print your notebook. This not quite as good because it leaves a thin but invisible space in the notebook.

One of those should do it.

If you were actually going to send the notebook to someone who has Mathematica, then my Presentations application has a nice feature. You can close the Input cell and then in a Text cell just preceding the Input cell paste an "Eval" button that will evaluate the closed cell. That allows you to include "boilerplate" code at the place where it is used in a notebook and hide it. The Eval button reminds the reader that the cell needs to be evaluated and allows him to do it without searching out the thin (and usually invisible) bracket.