Patent ID: 8308102

Claim:
A roll shaft structure for use in a thermal transfer printer to fix a first roll or a second roll, said first roll having a first roll inner diameter, said second roll having a second roll inner diameter, said second roll inner diameter being greater than said first roll inner diameter, said roll shaft structure comprising: a shaft body penetrating through said first roll or said second roll, and comprising a first notch and a second notch; a first ring sheathed around said shaft body and movable with respect to said shaft body, and having a first fixing part, wherein when said first ring is moved to a position between said first notch and said second notch and then said first ring is rotated, said first fixing part is engaged with said second notch, so that said first ring is fixed on said shaft body; a supporting plate arranged at a first end of said shaft body, and having a receiving part for receiving said first ring; and a stopping part arranged at a second end of said shaft body for stopping said first ring and avoiding detachment of said first ring from said shaft body, wherein when said first roll is sheathed around said shaft body, said shaft body is contacted with a first inner wall of said first roll, so that said first roll is fixed on said shaft body, wherein when said second roll is sheathed around said shaft body, said first ring is contacted with a second inner wall of said second roll, so that said second roll is fixed on said shaft body.