Amazon has released the Kindle DX, sporting a larger 9.7in screen designed to better handle formats such as professional documents or magazine and newspaper layouts.

The company said that the larger screen allows for more than 2.5 times the surface area of the smaller 6in Kindle 2, and will support larger, richer graphics formats. The DX will also sport 3.3GB of memory and display PDF files.

Amazon hopes that the new model will expand the device's reach beyond the traditional electronic-book market targeted by the smaller Kindle. Many newspaper and magazine publishers have put forward tablet devices such as the Kindle as a way to reclaim lost subscriptions.

"Personal and professional documents look so good on the big Kindle DX display that you'll find yourself changing ink-toner cartridges less often," said Amazon chief executive Jeff Bezos.

"Cookbooks, computer books and textbooks - anything highly formatted - also shine on the Kindle DX."

Amazon said that the device would be available for pre-order at $489 (£323) and will be shipping in the US later this summer. No word on a possible international release date was given.

When the device does launch, The New York Times, Boston Globe and Washington Post intend to offer reduced-price units as an incentive to buy newspaper subscriptions.

Several universities are also planning to offer the devices to students as an alternative to printed textbooks.