ends respectively abut against the colliding surface 91 of the lower locating piece 90 and the contact surface 81 of the upper locating piece 80 as shown in fig4 which is a cross sectional view of the preferred embodiment of the fuser device the control structure 60 includes a base piece 141 a first engaging portion 142 a second engaging portion 143 and a connecting portion 144 refer to fig5 simultaneously the first engaging portion 142 may be a first supporting shaft 1421 protruding from the base piece 141 or a first supporting rolling wheel 1422 rotatably disposed on the base piece 141 when the first engaging portion 142 is the first supporting rolling wheel 1422 the base piece 141 has a protruding shaft 1423 passing through the first supporting rolling wheel 1422 the second engaging portion 143 has a similar structure to the first engaging portion 142 and may be also a second supporting shaft 1431 protruding from the base piece 141 or a second supporting rolling wheel 1432 rotatably disposed on the base piece 141 when the second engaging portion 143 is the second supporting rolling wheel 1432 the base piece 141 has a protruding shaft 1433 passing through the second supporting rolling wheel 1432 regardless of the.