A Douglas County judge on Tuesday rejected a request for probation and sentenced a former Kansas University employee to serve more than two years in prison for having hundreds of child pornography images on his work computer.

“I in good faith cannot give you a probationary sentence because you don’t acknowledge that you have done anything wrong,” District Judge Sally Pokorny said.

Pokorny handed down the 31-month sentence to John G. Wallis, 62, of Topeka Tuesday afternoon. Wallis had pleaded guilty to one count of sexual exploitation of a child in September.

As part of a plea agreement prosecutors had agreed not to oppose the defense’s request for probation. Wallis, who worked as an electronics technologist in the physics and astronomy department from 1988 to 2007, faced what is called a “border box” under state sentencing guidelines. It is the judge’s discretion to give a defendant prison or probation.

But when Pokorny questioned him in court Tuesday, Wallis denied that the child pornography was his. He had given several excuses to the judge and doctors who evaluated him that he wasn’t the only one using the computer.

Among them, Wallis said the images could have come from a CD he confiscated from an international student and that the department frequently switched computers around.

“This happened quite often, so I really never had a computer that was really determined to be mine. It was just an extra computer that I could use,” Wallis said.

He also said two members of the KU department who could have helped clear him in the case have since died.

KU police responded in 2007 to a tip that Wallis might have child pornography on his computer and discovered images in deleted or unallocated space on the computer, according to prosecutors. The images were tested at a national database, and the victims in the images were not local children.

Pokorny, who heard evidence months ago in a preliminary hearing, said treatment Wallis would have received while on probation would not do any good if he still denied he did anything wrong.

She said if Wallis exhibits good behavior in prison, he could get credit not to serve 15 percent of his sentence. Once he’s released he must serve 24 months in post-release supervision.

He was taken into custody after the hearing. Wallis had been free on $4,500 bond.

Because she sentenced him to prison, Pokorny did not order Wallis to pay fines or court costs. But she said he must register as a sex offender for 10 years once he’s released.

Wallis has a right to appeal the sentence.