Apple’s iPad will continue to reign the swelling tablet market this year even though it already has several competitors from various computer and mobile-device companies, according to a report released by research firm Gartner.

Gartner said iPad, which is synonymous to the term “tablet,” sets the standards for what the device really is, thus, leaving a small room for alternatives.

The firm expects 70 million tablets to be sold within this year and about 108 million in 2012. The expected number is way beyond the 17.6 million tablet sales in 2011.

Google trails behind Apple in the second position. The firm said Google’s Android operating system is still insufficient to match up with Apple.

However, Gartner said Google’s shares will rise to 39 percent in 2015 from 20 percent this year while Apple’s shares will gradually drop to 47 percent from 69 percent.

Research in Motion’s Playbook tablet, which uses the new QNX platform, gets the third spot in the market this year with a 5.6 percent market shares, which Gartner believes will rise to 10 percent in 2015.

The firm said time and remarkable effort is required for RIM to obtain more customers and developers that will deliver a more innovative group of services and applications around QNX. Carolina Milanesi, Gartner analyst said this method will make a feasible alternative to Android or Apple.

Milanesi said organizations that will be interested in RIM’s new QNX-run tablet will consist of those who have RIM’s infrastructurre or those who have strict security requirements.