Encyclopedia Britannica will switch to an all-digital format, bringing its 244-year printing history to a close. It’s time to concentrate on expanding coverage for digital consumers rather than continuing to print the heavy, relatively expensive volumes, said the Chicago-based company that makes the reference books. The final print edition is the 2010 volume. The 32-volume set weighs 129 pounds and goes for $1,395. Since most of its users now access its information digitally, the encyclopedia maker will now focus its attention on making its information fit for digital consumption.