Photography giant Eastman Kodak has filed for chapter 11 bankruptcy protection as it seeks to boost its cash position and stay in business.

The move comes after the ailing US company failed to find a buyer for its trove of 1,100 digital imaging patents.

Kodak said in November that it could run out of cash in a year if it did not sell the patents, for which it hoped to fetch billions.

The firm said that it has secured 950 million US dollars (£615 million) in financing from Citigroup, and expects to be able to operate its business during bankruptcy reorganisation and pay employees.

The company, based in Rochester, New York, was pummelled by foreign competition and then severely shaken by the digital revolution. It has invested huge sums in new lines of inkjet printers.

Kodak's European business is not affected by the Chapter 11 move.

European managing director Philip Cullimore said: "In Europe we have seen a significant shift towards business-to-business imaging applications, and are weighted towards printing. These businesses in Europe are performing well and growing fast."