Tech giant Hewlett-Packard has dropped out of the Coalition for Patent Fairness, according to sources. The defection comes as lobbying heats up on a patent reform bill, with lobbyists predicting the Senate could vote on the issue before the end of the year. A coalition spokesman declined to comment. HP did not immediately return a press inquiry. HP’s logo is no longer displayed on the coalition’s Web site. The coalition has spent more than $1.93 million on lobbying this year with firms including Elmendorf Strategies, Patton Boggs, and Fierce, Isakowitz & Blalock.