RPT-TIMELINE-Sony's recent profit warnings

Sept 17 (Reuters) - Japan's Sony Corp forecast a much bigger than expected annual net loss of 230 billion yen ($2.14 billion) as it takes a big impairment charge for its struggling smartphone division. It's the company's sixth guidance cut under CEO Kazuo Hirai, who took the post in April 2012 promising to revive the storied electronics brand by focusing on mobile, gaming and imaging.