SAN JOSE, Calif. _ Apple Inc. is expected to introduce the newest iteration of its popular iPad tablet computer at an event in San Francisco next week, according to an invitation the Cupertino, Calif., tech giant sent to the media Tuesday.

The invitation from Apple has an image of a finger touching an iPad calendar icon displaying the number "7" with the tagline "We have something you really have to see. And touch." The event will take place March 7 in San Francisco.

The iPad has been one of the most successful products in Apple history. The company said it sold more than 15 million iPads in the fourth quarter of 2011 alone, which accounted for 57 percent of all tablets shipped worldwide in the holiday shopping season, according to IHS iSuppli. Apple shipped 40.5 million iPads in 2011, up from 15.1 million in 2010, IHS reported.

Demand for Apple products only seems to be increasing, as gigantic sales numbers for the iPad and other products led to a record-breaking fourth quarter for the company. Apple's latest major release, the iPhone 4S, sold a record 4 million devices in just three days after its October U.S. release.

A similar frenzy could take place if Apple debuts an updated iPad. Reports earlier this month that predicted Apple would announce a new iPad the first week in March said that the device would likely be available about a week after the announcement. Last year, sales of the iPad 2 began in the U.S. nine days after the announcement.

Blogs that claim to have obtained parts manufactured for the newest Apple tablet have reported that the next iPad will have a larger battery, leading to twice the battery power of an iPad 2, as well as a faster processor, more memory and a higher resolution display.

Apple has ridden tremendous sales of the iPad and its other signature devices to the summit of business, becoming the world's most valuable company in terms of market capitalization _ the value of all shares issued in a company _ and holding on to that title thanks to a stock price that seems to continuously grow. Apple stock topped $500 for the first time just this month but has already surpassed $530, after rising again Tuesday.

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