BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic cross-sectional view of a conventional duplex scanning device with a single scanning module; and
FIG. 2 is a schematic cross-sectional view of an automatic document feeder for duplex scanning according to a preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 2, a schematic cross-sectional view of an automatic document feeder for duplex scanning according to a preferred embodiment of the present invention is illustrated. The automatic document feeder 200 as shown in FIG. 2 comprises a sheet feeding tray 201, a pickup roller assembly 202, a first discharging roller assembly 203, a second discharging roller assembly 204, a first discharging tray 205, a second discharging tray 206, a scanning module 207, a first path 208, a second path 209 and a third path 210. The first discharging roller assembly 203 comprises a first driven roller 2031 and a first drive roller 2032. The second discharging roller assembly 204 comprises a second driven roller 2041 and a second drive roller 2042.
Please refer to FIG. 2 again. Hereinafter, the procedure of performing a single-side scanning operation by the automatic document feeder 200 is illustrated. First of all, the documents 220 to be scanned are placed in the sheet feeding tray 201. The pickup roller assembly 202 transports a first document 220 into a scan region 211 through the first path 208. When the document 220 is transported across the scan region 211, the scanning module 207 scans the document 220. Next, the second drive roller 2042 of the second discharging roller assembly 204 is rotated clockwise to drive anti-clockwise rotation of the second driven roller 2041, so that the second discharging roller assembly 204 transports the document 220 across the second path 209 to the first discharging roller assembly 203. Next, the first drive roller 2032 of the first discharging roller assembly 203 is rotated clockwise to drive anti-clockwise rotation of the first driven roller 2031, so that the document 220 is discharged to the first discharging tray 205. Meanwhile, the first document has implemented the single-side scanning operation. The remainder documents 220 in the sheet feeding tray 201 successively implement the single-side scanning operations identical to that for the first document 220. As a consequence, the documents 220 are stacked in the first discharging tray 205 in the same order as that of the original stack.
Please refer to FIG. 2 again. Hereinafter, the procedure of performing a duplex scanning operation by the automatic document feeder 200 is illustrated. First of all, the documents 220 to be scanned are placed in the sheet feeding tray 201. The pickup roller assembly 202 transports a first document 220 into a scan region 211 through the first path 208. When the document 220 is transported across the scan region 211, the scanning module 207 scans the first side of the document 220. Next, the second drive roller 2042 of the second discharging roller assembly 204 is rotated clockwise to drive anti-clockwise rotation of the second driven roller 2041, so that the second discharging roller assembly 204 transports the document 220 across the second path 209 to the first discharging roller assembly 203. Next, the first drive roller 2032 of the first discharging roller assembly 203 is rotated clockwise to drive anti-clockwise rotation of the first driven roller 2031, so that the document 220 is discharged to the first discharging tray 205. Meanwhile, the majority of the document 220 enters the first discharging tray 205, but the rear end of the document 220 is nipped between first driven roller 2031 and the first drive roller 2032 of the first discharging roller assembly 203. Next, the first driven roller 2031 of the first discharging roller assembly 203 is rotated clockwise, so that the document 220 in the first discharging tray 205 is transported to the scan region 211 through the third path 210. When the document 220 is transported across the scan region 211, the scanning module 207 scans the second side of the document 220. Next, the second driven roller 2041 of the second discharging roller assembly 204 is rotated clockwise, so that the document 220 is discharged to the second discharging tray 206. Meanwhile, the first document has implemented the duplex scanning operation. The remainder documents 220 in the sheet feeding tray 201 successively implement the duplex scanning operations identical to that for the first document 220. As a consequence, the documents 220 are stacked in the first discharging tray 205 in the same order as that of the original stack.
From the above description, when the automatic document feeder of the present invention performs the duplex scanning operation, the document needs to pass through the scan region for two times. That is, the duplex scanning operation by the present invention can be referred as a two-pass scanning operation. In comparison with the conventional three-pass scanning operation, the number of transporting the document through the scan region is reduced. Consequently, the time period of performing the duplex scanning operation is shortened.
It is noted that, however, those skilled in the art will readily observe that numerous modifications and alterations of the automatic document feeder may be made while retaining the teachings of the invention. For example, the motor for driving the rollers and the circuit board for control operations of the automatic document feeder can be integrated into the automatic document feeder. As a result, the duplex scanning operation can be done by using only the automatic document feeder without the cooperation of a flatbed image scanning portion. Alternatively, the automatic document feeder of the present invention can be mounted on a flatbed image scanning portion. In this circumstance, since the duplex scanning operation is performed by the scanning module included in the automatic document feeder, the scanning module included in the flatbed image scanning portion does not participate in the duplex scanning operation. As a consequence, the operative space 120 for accommodating the scanning module in the flatbed image scanning portion is not required, and thus the length and the overall volume thereof are reduced. Moreover, the first discharging tray 205 and the second discharging tray 206 can be made collapsed or expanded in order to save more space. Alternatively, the automatic document feeder of the present invention can be combined with a printer to form as a multifunction peripheral capable of performing the duplex scanning operation.
While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.
Patent Application
20070280762
