Where do I find clients for a new printing company?
Unless you are very well funded (and I mean that you have enough money set aside to keep you afloat for at least 8 months, which includes a normal salary for you, and the costs you will incur for rental, staff, supplies & lease expenses) take it slow. Concentrate on certain kinds of jobs that the equipment you lease can easily handle with maximum performance/ output with min headaches for you. If you are good - service and results-wise, word will get around and people in Chamber(s) you belong to will start calling you.
Volunteer your services to several area non-profits, in exchange for print and online recognition. They have a slew of connections and are in dire need of any assistance with their printing needs. You get to do something nice for a worthy organization, and are helping to build your business ( and good reputation) in the process!
Last but least (actually this should be first!!) get a professional logo designed, a business card and at least one sales sheet ( an oversized piece that can act as a direct mail postcard is fine), along with a basic website ( 4 pages is fine to start). Hire a good designer and copywriter, so that your firm shines from the get-go.
Best of luck with your new venture!