Quad/Graphics Inc. says its plans to begin closing plants and taking others steps to cut $100 million in costs after the Wisconsin-based printing company posted disappointing financial results.Chief executive Joel Quadracci said Tuesday that Quad's third quarter financial performance was "challenging and below our expectations."Quadracci says the Sussex-based company is taking "swift and decisive action," and announcing a $100 million cost reduction program to bring the company's cost structure in line with revenues.The Milwaukee Journal Sentinel reports the company did not say how many jobs it might cut, or identify any plants for closing.Quad is the biggest printer of magazines and catalogs in North America. The company operates 57 printing plants in the U.S. and another eight outside the country, and employs 24,000 people worldwide.