This phase of the process may be very easy or very difficult, depending in large degree upon the examiner assigned to your application. At any time from a few weeks to a year or more (yes) after you send in the application, the examiner will return an office action. This will normally come as a registered letter to you or to your attorney, and sets out the examiner’s objections to your claims, one by one.
If the specification is detailed and specific enough, the invention is well clear of the prior art, and the claims are well written, the examiner may have few objections (though there will always be a few; no examiner wants to look “easy”!) Otherwise, the objections may run to several pages. Claims will often be rejected, with the examiner’s reasons given for each.
It is up to you, your attorney, and VentorBridge should you so desire, to answer these objections. Typically this involves pointing out some bit of the specification which the examiner may have overlooked, explaining why your invention is different from the one cited in some earlier patent. Often a claim will have to be rewritten, or abandoned and (if possible) replaced with one or more new ones. Normally you will have up to six months to respond.
Much more information about Office Actions and how to respond to them is given here.
Should you respond satisfactorily, the PTO will issue a Notice of Allowability and a bill for fees due. Once that bill is paid, and always (for obscure historical reasons) on the following Tuesday, the actual patent will issue.
Your first notification this has happened, by the way, will likely not come from the PTO. Washington swarms with entrepreneurs who’ll mail you offers of your patent’s first page handsomely framed, engraved on plaques, printed on lampshades (they’ll even sell you the lamp!) or applied to other expensive knick-knacks. Whether you buy or not, of course, is up to you. But it’s a sure sign that the patent has issued, or is about to, and you’ll be getting it from the PTO through registered mail very soon.