For Rudi Lenz, president and CEO of Sun Chemical, 2008 marked the first time he has attended drupa Rudi Lenz as the leader of Sun Chemical, and he used the opportunity to its fullest by staying the entire 14-day run.     “I have met a lot of customers here, which is most important for me,” said Mr. Lenz. “It’s important that we listen to our customers.     The key to success is developing partnerships with customers, suppliers and co-suppliers to the industry.     “We ar...