* Capital investment to 2015 to be at least Y1 trillion
* To spend Y20-30 bln on new cartridge plant in Europe
* Seeks to expand Asian sales force to more than 10,000 staff
* Has not been asked to sell stake in Hitachi display unit
* Shares in Canon close down 1.4 pct, underperforming Nikkei (Adds fund manager comment in final two paragraphs)
By Isabel Reynolds and Reiji Murai
TOKYO, Jan 11 (Reuters) - Camera and printer giant Canon Inc said it will buy back more of its shares, as soon as this year if the price falls, in keeping with a strategy of having treasury stock on hand in case an attractive acquisition target comes along.
It will also build a new cartridge plant in Europe and boost its sales force in Asia to more than 10,000 as quickly as possible from the current 3,000, to take advantage of the region's rapid economic growth, Chairman Fujio Mitarai said in an interview on Tuesday.
He also said there were no plans to change the company's 25 percent stake in Hitachi unit Hitachi Displays. Media have reported that Foxconn subsidiary Hon Hai Precision Industry Co was planning to invest more than $1 billion in the unit, reducing Hitachi's holding.
Canon already holds about 100 million of its own 1.3 billion shares and adding to this only makes financial sense, Mitarai said.
"Looking at interest rates ... rather than keeping money in a bank, it is more profitable to buy back shares so that you don't have to pay dividends."
Asked about specific plans for the financial year that began in January, he declined to give a target percentage, but said: "If the share price goes down, of course we will buy them."
Canon is keen on possible acquisitions, particularly in medical and industrial equipment, as it works towards an ambitious target of returning profits to their 2007 peak of 757 billion yen ($9.1 billion) in 2012. It expects to have made 390 billion yen in the year just ended on Dec. 31.
FOCUS ON CHINA
Canon executives nailed down the specifics of a five-year corporate strategy earlier this month and Mitarai said capital investment would be at least 1 trillion yen over the five-year period, at a pace of about 200 billion to 300 billion yen annually.
The company's investment in sales operations needs to focus on China, Asia and developing countries, he said, but added that Canon was having difficulty finding sales staff in China.
Separately, Mitarai said the company would spend about 20 billion to 30 billion yen on building a new toner cartridge plant in Europe, on which it planned to start work this year.
The move is part of a strategy to produce and recycle cartridges closer to the end user, to save on fuel and other distribution costs.
Canon already has a similar plant in Virginia to serve the U.S. market, but Mitarai said cartridges for Asia would continue to be produced in Japan. The company is currently seeking real estate for the European plant, but has not decided on a particular country, he said.
Mitarai said the company had not been approached about selling its 25 percent stake in Hitachi Displays and it had no plans to either raise or lower its stake in the venture, even if a third party were to invest.
"Our stake may fall in percentage terms, but we don't mind. Being a shareholder is not the point. The point is joint development," Mitarai said.
Shares in Canon fell 1.4 percent to 4,155 yen on Tuesday, underperforming a 0.3 percent decline in the Nikkei stock average.
Fund manager Naoki Fujiwara of Shinkin Asset management said sales projections for the current year would be investors' next focus, with results for 2010 mostly factored in ahead of the company's annual earnings report on Jan. 27.
"In the short term, things look very stable," Fujiwara said. "But in terms of growth prospects, there doesn't seem to be any reason for the share price to rise." ($1=82.95 Yen) (Editing by Edwina Gibbs and Edmund Klamann)