Document processing apparatus with rotatable gap sensor

Abstract

A document processing apparatus includes a sheet passageway, a sheet-feeding mechanism and a rotatable gap sensor. The sheet-feeding mechanism transports a first sheet and a second sheet successively through the sheet passageway. The rotatable gap sensor is rotated by movement of the first sheet and the second sheet for the detection of the presence of the first sheet and the second sheet. The rotatable gap sensor generates a plurality of state signals with respect to rotating states of the rotatable gap sensor.

1 . A document processing apparatus, comprising:
 a sheet passageway;   a sheet-feeding mechanism, for transporting a first sheet and a second sheet successively through the sheet passageway; and   a rotatable gap sensor, for detecting presence of the first sheet and the second sheet, the rotatable gap sensor being rotated by movement of the first sheet and the second sheet, and for generating a plurality of state signals with respect to rotating states of the rotatable gap sensor.   
   
   
       2 . The apparatus according to  claim 1 , further comprising:
 a control circuit, electrically connected to the sheet-feeding mechanism and the rotatable gap sensor, for controlling the sheet-feeding mechanism to start to transport the second sheet into the sheet passageway according to the state signals generated in response to the detection of the first sheet.   
   
   
       3 . The apparatus according to  claim 1 , further comprising:
 a scan module, for acquiring images of the first sheet and the second sheet.   
   
   
       4 . The apparatus according to  claim 3 , further comprising:
 a control circuit, electrically connected to the scan module, the sheet-feeding mechanism and the rotatable gap sensor, for controlling the scan module to start to scan the first sheet and the second sheet according to the state signals.   
   
   
       5 . The apparatus according to  claim 1 , wherein the rotatable gap sensor comprises:
 a roller, provided with a plurality of through holes, the roller being rotated by the movement of the first sheet and the second sheet through contact with the first sheet and the second sheet; and   a transmissive optical detector, disposed on either side of the roller, for emitting an optical signal and receiving the optical signal penetrating through the through holes.   
   
   
       6 . The apparatus according to  claim 5 , wherein the rotatable gap sensor further comprises:
 a pressing roller, disposed opposite the roller, for pressing the first sheet and the second sheet against the roller.   
   
   
       7 . The apparatus according to  claim 5 , wherein the roller comprises a rim for contacting the first sheet and the second sheet, and the rim is provided with a high friction surface. 
   
   
       8 . The apparatus according to  claim 5 , wherein the transmissive optical detector comprises a photo-interrupter. 
   
   
       9 . The apparatus according to  claim 8 , wherein the photo-interrupter comprises a transmitting end for emitting the optical signal and a receiving end for receiving the optical signal. 
   
   
       10 . The apparatus according to  claim 1 , wherein the rotatable gap sensor comprises:
 a roller, provided with a plurality of reflective blocks, the roller being rotated by the movement of the first sheet and the second sheet through contact with the first sheet and the second sheet; and   a reflective optical detector, disposed on one side of the roller, for emitting an optical signal and receiving the optical signal reflected by the reflective blocks.   
   
   
       11 . The apparatus according to  claim 10 , wherein the rotatable gap sensor further comprises:
 a pressing roller, disposed opposite the roller, for pressing the first sheet and the second sheet against the roller.   
   
   
       12 . The apparatus according to  claim 10 , wherein the roller comprises a rim for contacting the first sheet and the second sheet, and the rim is provided with a high friction surface. 
   
   
       13 . The apparatus according to  claim 10 , wherein the reflective optical detector comprises a transmitting end for emitting the optical signal and a receiving end for receiving the optical signal. 
   
   
       14 . The apparatus according to  claim 1 , further comprising:
 a supply tray for supporting the first sheet and the second sheet to be transported.   
   
   
       15 . The apparatus according to  claim 1 , wherein the rotatable gap sensor comprises:
 a shaft;   a roller, mounted on the shaft and rotated by the movement of the first sheet and the second sheet through contact with the first sheet and the second sheet;   an encoding disk, mounted on the shaft and rotated in synchronicity with the roller, the encoding disk being provided with a plurality of through holes; and   a transmissive optical detector, disposed on either side of the encoding disk, for emitting an optical signal and receiving the optical signal penetrating through the through holes.   
   
   
       16 . The apparatus according to  claim 15 , wherein the transmissive optical detector comprises a photo-interrupter. 
   
   
       17 . The apparatus according to  claim 16 , wherein the photo-interrupter comprises a transmitting end for emitting the optical signal and a receiving end for receiving the optical signal. 
   
   
       18 . The apparatus according to  claim 1 , wherein the rotatable gap sensor comprises:
 a shaft;   a roller, mounted on the shaft and rotated by the movement of the first sheet and the second sheet through contact with the first sheet and the second sheet;   an encoding disk, mounted on the shaft and rotated in synchronicity with the roller, the encoding disk being provided with a plurality of reflective blocks; and   a reflective optical detector, disposed on one side of the encoding disk, for emitting an optical signal and receiving the optical signal reflected by the reflective blocks.   
   
   
       19 . The apparatus according to  claim 18 , wherein the reflective optical detector comprises a transmitting end for emitting the optical signal and a receiving end for receiving the optical signal.