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Zachery Ty Bryan allegedly punched his then-girlfriend and threatened to kill her over the summer ... and she now has a 5-year restraining order against him.

According to court documents obtained by TMZ, the victim first contacted police after the "Home Improvement" star allegedly clocked her in the right temple on July 3 ... after she playfully bit his nipple while they were lying down together. Gallery Launch Gallery Getty

The woman also told cops she was scared for her safety just days later when she and Bryan got into a verbal altercation. She claimed he threatened to end her life and said ... "Shut the f*** up or I'm gonna shut you up".

During the verbal incident, the woman told police he snatched their dog and locked himself in a room ... and then proceeded to pu

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