Patent ID: 8736928

Claim:
A sheet feed scanner, capable of scanning a document, wherein the sheet feed scanner comprises: an automatic document feeder, capable of feeding the document, wherein the automatic document feeder comprises; a top cover; a pickup arm, disposed under the top cover and capable of swinging relative to the top cover, so as to feed the document into the auto document feeder; and a feeding gear, connecting with the pickup arm; a flatbed scanner, disposed under the auto document feeder, and capable of scanning the document, wherein the flatbed scanner comprises: a scanning module, capable of reading an image of the document; a scanning module gear, connecting with the scanning module; and a stopping structure, capable of stopping the scanning module from moving; and a power-switching mechanism, capable of transmitting a driving power to the auto document feeder or the scanning module, wherein the power-switching mechanism comprises: a first shaft, comprising a protrusion portion; a power source, capable of driving the first shaft to rotate; a clutch, fitting onto the first shaft, and comprising a sliding groove, a first incline and a second incline, wherein the protrusion portion is disposed to the sliding groove, so as to enable the clutch to shift relative to the first shaft; a first gear, fitting onto the first shaft, and disposed at a side of the clutch; a second gear, fitting onto the first shaft, and disposed at another side of the clutch; and an elastic limitation structure, pushing the first incline or the second incline of the clutch, wherein the stopping structure generates a first reaction force to the scanning module when the scanning module moves toward the stopping structure to contact with the stopping structure, so as to enable the clutch to disengage from the second gear, while the top cover generates a second reaction force to the pickup arm when the pickup arm swings upward to contact with the top cover, so as to enable the clutch to disengage from the first gear.