The quiet of Bento Box’s offices is broken by a series of screams, interspersed with loud thumps. Heads look up from computer workstations to see that it is not an incident of escalating workplace violence, just some random theatrics by Kristen Schaal, the voice of Louise on the animated Fox series “Bob’s Burgers.” She’s dropped by to loop some dialogue with show creator Loren Bouchard, although her performance appears to have nothing to do with the task at hand.

“Never a dull moment,” laughs Scott Greenberg, who founded animation studio Bento Box in 2009 with Mark McJimsey and Joel Kuwahara.

From the outside, the building that houses the company’s HQ — located across the street from a Handy Market in Burbank, Calif., in a building that once was a church and, later, a convalescent home — hardly looks like a place bursting with creative excitement. But Bento Box’s reputation for keeping costs low and delivering quality work has made it one of the fastest-growing animation shingles in Hollywood. It’s is responsible for most of Fox’s current animated series lineup, and has opened up an outpost in Atlanta, where it can pass along the Georgia tax credit savings to its clients.

Greenberg came to Bento Box from his post as president and CEO of Film Roman, the animation house behind “The Simpsons,” “King of the Hill” and numerous other 20th Century Fox Television animated shows. McJimsey and Kuwahara met two decades ago working on “The Simpsons,” and went on to work together as producers on another Film Roman animated series, ABC’s “The Goode Family” (2009).

“When Mark and I would worked together, we saw how one step leads to another step, and how we could make it go quicker, better, faster,” Kuwahara says.

At Bento Box, they put their ideas into full effect with a paperless, fully digital workflow that has artists drawing storyboards directly onto Cintiq tablet computer screens with Storyboard Pro software, which Kuwahara helped develop. The files are imported into another software program, Harmony, where virtual timing sheets are filled out, then transferred to one of Bento’s partner studios in Korea to be animated. The completed animation is subsequently sent back to Burbank for final tweaking on the same Cintiq tablets.

“At other studios in Korea, you would see stacks of paper that have to be run through a scanner,” Kuwahara says. “We’ve eliminated that whole process.”

Two of Bento Box’s first productions, TBS’ “Neighbors From Hell” and Fox’s”Allen Gregory,” co-created by Jonah Hill, had only single-season runs in 2010 and 2011, respectively, but the company hit its stride recently when it scored a 22-episode, fourth season pickup for “Bob’s Burgers,” as well as a second-season order for Comedy Central series “Brickleberry.”

Bento Box also is developing Comedy Central show “Gajillionaires,” created by Yoni Brenner (“Ice Age: Dawn of the Dinosaurs”); partnering with Lionsgate on an animated feature starring Tyler Perry’s “Madea” character; and financing and producing a show with the creators of YouTube puppet sensations Glove & Boots.

On top of that, Greenberg estimates Bento Box produces 90% of Fox’s animated pilots, with recent orders including “Murder Police” and shows from comedians Russell Brand and Demetri Martin.

Bento Box has about 100 employees in its Burbank facility and 30 in a nearby building in North Hollywood, and it expects to add another 70 local workers in the coming months to accommodate the increasing workload.

It also has 50 employees at its new studio in Atlanta, which opened in June. That outpost is handling the bulk of the production on two new animated series, IFC’s “Out There” and Hulu’s “The Awesomes,” co-created by SNL’s Seth Meyers.

“It’s a second pipeline that allows us to produce at that cable price point and expand our product line,” Greenberg says.

The company is able to achieve that economy, in part, by taking advantage of Georgia’s 20%-30% tax credit.

“I think what we’re really becoming is a true independent studio,” Greenberg says. “What Endemol and Fremantle were like 10 years ago (in the reality TV space), that’s kind of what we’re becoming — a full-service shop, partnered with the networks and the studios.”