Patent ID: 7389925

Claim:
A scanner, comprising: a first shaft; a second shaft; a photoelectric sensor for scanning a medium to produce an image; a carriage movably positioned on the first shaft for carrying the photoelectric sensor; a light source module movably positioned on the second shaft for generating a light beam for the medium; a driving module coupled to the carriage for driving the carriage to move a first offset along the first shaft; and a locking module coupled to the light source module and the carriage, the carriage ensures the light source module moves a second offset along the second shaft through the locking module when the carriage moves with the first offset, the locking module comprising: a permanent magnet positioned fixedly on the light source module; and an electromagnet positioned fixedly on the carriage; wherein the second shaft includes a groove; the light source module includes a tenon connected to the permanent magnet; when the light source module is at an initial position, if the electric current supported to the electromagnet is turned off, then the permanent magnet attracts the second shaft and lodges the tenon in the groove for preventing the light source module from moving along the second shaft, and if the electric current supported to the electromagnet is turned on, then the electromagnet attracts the permanent magnet and takes the tenon away from the groove for allowing the light source module to move along the second shaft.