To provide replacement, mounting, and maintenance of a driving motor as a consumable part, without requiring time and effort of an operator, by simplifying the maintenance work of replacement parts.

An inner boundary face of a mounting holder is formed into a shape that is almost equal to the outer shape of the body of the drive motor. Each rail groove with a recessed groove shape is provided at part of both ends of the outer boundary face of the mounting holder in the same linear direction. A part of a driving mechanism unit, within the device or a side edge of the circuit board with a cut, is inserted to the rail groove with the recessed groove shape, and then in this mounting structure of the driving motor, the driving motor is held and fixed in such a way that the drive motor is engaged with an input gear of the driving mechanism unit within the device.