What is the proper and responsible way to dispose of an old and broken laser printer?

Recycle centers usually offer recycling for electronics. Call your local recycle center and ask.

My city does an old ‘electronic’ recycle day every third Saturday. That’s where I trashed mine (luckily for free)

Look for electronic recycling near you. Best Buy often collects old stuff to recycle.

Cities and counties often have electronic recycling. When I lived in Los Angeles, they had drive up centers open all the time, Other places I have lived had special days 2 or 3 times a year.

If you are buying new equipment, ask the store if they take old stuff. Even if you are not buying new, a store like Best Buy might take it.

www.bestbuy.com/recycling

And some stores might even give you cash back for your old electronics. Be sure to ask.

http://1800recycling.com/

more specifically: http://1800recycling.com/find/recycling-locations/electronics/
then click printers