Patent ID: 7549812

Claim:
A print control module of a thermal printer, the print control module comprising: a housing; a transmission device installed within the housing, comprising: a motor; and a transmission gear set for outputting power of the motor; a power switch mechanism installed within the housing, comprising: a rotating arm plate; a first gear, installed on the rotating arm plate for meshing with a gear of the transmission gear set in a rotatable manner relative to the first rotating arm plate; a first planetary gear installed on the first rotating arm plate for meshing with the first gear for rotating around the first gear in a rotatable manner relative to the first rotating arm plate; a fixing component installed on the first rotating arm plate; a second rotating arm plate; a second gear installed on the second rotating arm plate in a rotating manner relative to the second arm plate; a second planetary gear installed on the second rotating arm plate for meshing with the second gear for rotating around the second gear in a rotatable manner relative to the second rotating plate; and an axle connected between a spindle of the first gear and a spindle of the second gear for simultaneously driving the first gear and the second gear; a power transmission gear installed within the housing in a rotatable manner relative to the housing; and a step switch mechanism installed within the housing, comprising: a third gear installed within the housing for meshing with a print head gear set in a rotatable manner relative to the housing; a cam rotating arm connecting to the third gear comprising a flat surface and an arc surface for switching operation step of the thermal printer through the flat surface and arc surface; a third planetary gear installed on the cam rotating arm for meshing with the power transmission gear for rotating around the power transmission gear in a rotatable manner relative to the cam rotating arm; a rotating arm installed within the housing in a rotatable manner relative to the housing, an end of the rotating arm contacting the cam rotating arm, another end of the rotating arm moving along an arc; and a clutch gear installed on another end of the rotating arm; wherein when the motor rotates in a first direction, the first planetary gear meshes with the step switching mechanism to output power to the step switching mechanism, and when the motor rotates in an opposite direction to the first direction, the fixed component fixes the step switching mechanism, the second planetary gear meshes with the power transmission gear to transfer power to the power transmission gear; wherein the flat surface and the arc surface control the rotation of the rotating arm so as to control the clutch gear to mesh with a ribbon gear set.