'Wheel of Fortune' Back to Business After Jim Thornton’s Firing, Ryan Seacrest All Smiles on Set

“Wheel of Fortune” did not use an announcer during its latest taping … following the firing of longtime announcer Jim Thornton after he was allegedly caught on a child-predator website … TMZ has learned.

A source close to production tells TMZ … Season 44 rolled cameras Tuesday on the Sony Studios lot, with the usual introductions and announcements noticeably absent.

As we first reported … editors have also begun scrubbing Thornton’s voice from episodes already taped for the current season. We’re told they did not have anyone introduce hosts Ryan Seacrest and Vanna White for Tuesday's taping.

Our source tells TMZ that Ryan and Vanna were both in good moods, and Ryan was cracking jokes with the guests and the crew.

There was no mention of Jim or the controversy that erupted last week after TMZ broke the story of Jim being detained after an American Airlines flight in May … where a fellow passenger reported him after seeing him type inappropriate messages in a chatroom for pedophiles.  

Jim denied intentionally being inside the chat ... claiming he was accidentally sent the link by someone he worked with at a suicide prevention hotline, where he helps others.

The timestamps on the photos appear to show Jim remaining in the chatroom in question for close to an hour.