Boxer Jermain Taylor -- I Have Mental Problems

Boxer Jermain Taylor is adamant he's NOT a criminal -- and blames his recent string of bizarre and troubling behavior on mental illness.

Taylor appeared in an Arkansas courtroom moments ago in connection with an incident at an MLK Day parade earlier this year in which he allegedly pulled a gun on a family and fired multiple shots.

The former IBF middleweight champ pled not guilty by reason of mental disease or defect ... and his attorney requested that the boxer undergo another mental evaluation.

But instead of returning to his rehab facility -- where he allegedly assaulted another man this month -- the judge ordered Taylor to go to jail because he violated his conditions of release.

Taylor's attorney tells TMZ Sports, "He’s in good spirits. I don’t think he’s upset about it. He wants to be out. He has kids."