HUDSON, Wis. - Wisconsin Gov. Scott Walker said he takes the recall effort against him seriously and is preparing to stand on his record in what he expects to be a vigorous fight to keep his job.

Appearing in Hudson, Wis., on Friday to break ground on a new distribution center, Walker said he expects his opponents to secure sufficient petitions to force a recall election. On Thursday, the chief recall group, United Wisconsin, announced that it has collected 507,000 of the 540,000 signatures needed, with a month to go in the campaign.

"We take it seriously, when you have tens of millions of dollars coming in from other states, you have to take that seriously,’’ he said. He said he has raised more than $5 million to fight an expected recall election, possibly next spring. “We’ve had literally thousands of people sign up, particularly people who are interested and frustrated – want to make sure the integrity of the petition process is legitimate.’’

“I’ve assumed from day one … between activists, and if they need to do so, paid circulators, they’ll get enough signatures,’’ he said. “I’m pretty sure that will happen.

“ For me, I’m an optimist. I view it as an opportunity to reaffirm the good that we’ve done.’’

Walker, a Republican finishing his first year in office, attended a groundbreaking ceremony at the site of a new warehouse. Uline Shipping Supply Specialists is moving a distribution center from Eagan, Minn., to a business park on the outskirts of Hudson.

Uline is a leading distributor of shipping materials, and its products include boxes, tape and pallet trucks. The company is building a 600,000-square-foot warehouse that will employ 200 people when it opens in Spring of 2013.

Small groups of pro- and anti-Walker demonstrators greeted his arrival and departure, a distant echo of the demonstrations that seized the state Capitol in Madison last winter. Walker’s bill to greatly restrict collective bargaining for public employees stirred a series of large protests and a walkout by Democrats in the state senate before it was passed and signed into law. The recall effort, a rare attempt to remove a sitting U.S. governor, grew out of those protests.

“They can worry about recall campaigns – I worry about the campaign to help the people of the state of Wisconsin create 250,000 jobs,’’ Walker said.

Democrats have not yet settled on an opponent to Walker. “I expect to run against big money from the unions in Washington,’’ he said. “Whether or not they put a candidate attached to that, it doesn’t matter. That’s what I’ll be running against.’’

He said while other states facing deficits have raised taxes, resorted to accounting “gimmicks,’’ had massive public employee layoffs, or cut core services for the needy, he and the Republican-controlled Legislature balanced the state budget without using any of these options. He said he is “thinking more about the next generation than the next election.’’

“We’re going to focus on getting the grass roots effort out, because we think there’s a lot of people who have quietly watched what happened thus far … they were part of the majority that elected us last year. They’d like us to keep the promises we made.’’

Asked if the recall movement and demonstrations were affecting his ability to do his job, he said he has kept his focus on job-creation, but it has been hard on his family.

“The biggest challenge is for my family,’’ he said. “My kids still go to school in Wauwatosa. We’ve had busloads of protesters in my neighborhood … my kids face attacks on Facebook. We’ve had verbal attacks on my wife and my kids along the way. That’s probably been the bigger challenge for me personally.”

"They have a right to protest, he added. "But their voices shouldn’t drown out the majority of people ...  the majority of them last year elected me to be their governor to do what we’ve done."

Joan Schneider, a retired teacher from from River Falls, carried an anti-Walker sign outside the groundbreaking site and said she supports the recall. Of Walker’s union bill, she said: “It undid what we worked for for 35 years.’’

John Danneker, a small business owner from Maiden Rock, held a pro-Walker sign. “I support the efforts he’s doing to create jobs in the state of Wisconsin,’’ he said. “I think he’s doing what the people of the state of Wisconsin want him to do.’’