Image scanning device and sheet feeding method applied therein

An image scanning device includes an upper shell, a feeding shaft pivotally connected to the upper shell, a feeding roller mounted around the feeding shaft, a sensing roller, a motor, a lower shell pivotally covered to the upper shell, a plurality of springs and a contact image sensor. The sensing roller is mounted around the feeding shaft. The motor is connected with the feeding shaft. The motor drives the feeding shaft to rotate in different speeds. The plurality of the springs are mounted to the lower shell. The contact image sensor is mounted to the plurality of the springs. A top surface of the contact image sensor is capable of abutting against lower portions of outer surfaces of the feeding roller and the sensing roller by virtue of the plurality of the springs elastically abutting against a bottom surface of the contact image sensor.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is based on, and claims priority from, Taiwan Patent Application No. 106110396, filed Mar. 28, 2017, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to an image scanning device and a sheet feeding method applied therein, and more particularly to an image scanning device capable of automatically detecting thicknesses of sheets which are to be scanned to automatically adjust feeding speeds of the sheets which are to be scanned, and a sheet feeding method applied therein for realizing successfully feeding the sheets which are to be scanned and have different thicknesses to complete scanning the sheets effectively.

2. The Related Art

Generally, a conventional image scanning device drives a transmission system by virtue of a motor to drive a feeding roller for feeding sheets which are to be scanned one after another. When the sheet which is to be scanned is thicker, a needed torsion of the motor is larger, a current of the motor need be increased for realizing that the needed torsion of the motor is larger. In order to ensure that the sheets which are to be scanned and have different thicknesses are capable of being fed successfully by the conventional image scanning device, a power system is disposed to provide the needed largest current for the thicker sheet which is to be scanned so as to provide the largest torsion of the motor, so a constant current value is provided for the motor so as to realize a constant torsion of the motor and provide a constant feeding speed of the feeding roller to feed the sheets which are to be scanned and have the thicknesses of being less than or equal to a set thickness.

However, because usage environments of the conventional image scanning device are increased, in order to carry the conventional image scanning device conveniently, the conventional image scanning device becomes smaller and smaller, and correspondingly a conventional portable image scanning device is emerged, the conventional portable image scanning device provides power by a current USB interface, nevertheless, an electrical power provided by the current USB interface is 2.5 W, a power supply is limited, when the thicker sheet which is to be scanned need be fed, a feeding speed of the thicker sheet need be slowed down and the torsion of the motor need be increased to realize feeding the thicker paper which is to be scanned. In another case, because the current provided by the power system is limited, the conventional image scanning device judges the thicknesses of the sheets which are to be scanned and adjust the feeding speeds of the sheets which are to be scanned by virtue of manual labors that brings an inconvenience in use.

Thus, in order to solve the above-mentioned problems, the present invention provides an innovative image scanning device capable of automatically detecting the thicknesses of the sheets which are to be scanned to automatically adjust the feeding speeds of the sheets which are to be scanned, and a sheet feeding method applied therein for realizing successfully feeding the sheets which are to be scanned and have the different thicknesses to complete scanning the sheets effectively.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an image scanning device. The image scanning device includes an upper shell, a feeding shaft pivotally connected to the upper shell, a feeding roller fastened to and mounted around the feeding shaft, a sensing roller, a motor, a lower shell pivotally covered to the upper shell, a plurality of springs and a contact image sensor. The feeding roller projects beyond a bottom surface of the upper shell. A diameter of the sensing roller is the same as a diameter of the feeding roller. The sensing roller is fastened to and mounted around the feeding shaft, and the sensing roller is located adjacent to one side of the feeding roller. The motor is connected with the feeding shaft. The motor drives the feeding shaft to rotate in different speeds and bring along the feeding roller and the sensing roller to rotate simultaneously. The plurality of the springs are mounted to the lower shell and are capable of stretching and retracting upward and downward with respect to the feeding shaft. The contact image sensor is mounted to the plurality of the springs and is capable of moving upward and downward with respect to the feeding shaft. A top surface of the contact image sensor faces to lower portions of outer surfaces of the feeding roller and the sensing roller, and the top surface of the contact image sensor is capable of abutting against the lower portions of the outer surfaces of the feeding roller and the sensing roller by virtue of the plurality of the springs elastically abutting against a bottom surface of the contact image sensor.

Another object of the present invention is to provide a sheet feeding method applied in an image scanning device for scanning sheets. The image scanning device includes a roller element, a contact image sensor, a plurality of springs, and a motor driving the roller element to rotate in different speeds. The contact image sensor is mounted to the plurality of the springs. A top surface of the contact image sensor is capable of abutting against a lower portion of an outer surface of the roller element. Specific steps of the sheet feeding method are described hereinafter. Drive each of the sheets which are to be scanned to be fed forward to a preset position by virtue of the roller element rotating. Each of the sheets which are to be scanned pushes against the contact image sensor to move downward. The plurality of the springs are compressed. An interval is formed between the lower portion of the outer surface of the roller element and the top surface of the contact image sensor. Reading image read values of the outer surface of the roller element, and the contact image sensor records the image read values of the outer surface of the roller element at different intervals, namely different distances of which each is between the outer surface of the roller element and the top surface of the contact image sensor, confirm the distances of which each is between the outer surface of the roller element and the top surface of the contact image sensor according to the image read values of the outer surface of the roller element, namely thicknesses of the fed sheets which are to be scanned. According to the different intervals of which each is between the outer surface of the roller element and the top surface of the contact image sensor, different feeding speeds are separately set corresponding to rotation speeds of the motor. According to the thicknesses of the fed sheets which are to be scanned, automatically choose corresponding feeding speeds to feed the sheets which are to be scanned so as to proceed with scanning.

Another object of the present invention is to provide a sheet feeding method applied in an image scanning device for scanning sheets. The image scanning device includes a feeding roller, a sensing roller, a contact image sensor, a plurality of springs, and a motor driving the feeding roller and the sensing roller to rotate in different speeds. The contact image sensor is mounted to the plurality of the springs. A top surface of the contact image sensor is capable of abutting against lower portions of outer surfaces of the feeding roller and the sensing roller. Drive each of the sheets which are to be scanned to be fed forward to a preset position by virtue of the feeding roller rotating. Each of the sheets which are to be scanned pushes against the contact image sensor to move downward, the plurality of the springs are compressed, an interval is formed between the lower portions of the outer surfaces of the feeding roller and the sensing roller, and the top surface of the contact image sensor. Read image read values of the outer surface of the sensing roller, the contact image sensor records the image read values of the outer surface of the sensing roller at different intervals, namely different distances of which each is between the outer surfaces of the feeding roller and the sensing roller, and the top surface of the contact image sensor, confirm the distances of which each is between the outer surfaces of the feeding roller and the sensing roller, and the top surface of the contact image sensor according to the image read values of the outer surface of the sensing roller, namely thicknesses of the fed sheets which are to be scanned. According to the different intervals of which each is between the outer surfaces of the feeding roller and the sensing roller, and the top surface of the contact image sensor, different feeding speeds are separately set corresponding to rotation speeds of the motor. According to the thicknesses of the fed sheets which are to be scanned, automatically choose corresponding feeding speeds to feed the sheets which are to be scanned so as to proceed with scanning.

As described above, the image scanning device applies the sheet feeding method to set the different feeding speeds according to the different intervals of which each is between the outer surfaces of the feeding roller and the sensing roller, and the top surface of the contact image sensor by virtue of the contact image sensor recording the image read values at the different intervals (namely the different distances) of which each is between the outer surfaces of the feeding roller and the sensing roller, and the top surface of the contact image sensor before scanning. Furthermore, read the image read values of the outer surface of the sensing roller, confirm the distances of which each is between the outer surfaces of the feeding roller and the sensing roller, and the top surface of the contact image sensor according to the image read values of the outer surface of the sensing roller, namely the thicknesses of the fed sheets which are to be scanned, and then according to the thicknesses of the fed sheets which are to be scanned, automatically choose corresponding feeding speeds to feed the sheets which are to be scanned so as to proceed scanning. As a result, the image scanning device is capable of automatically detecting the thicknesses of the sheets which are to be scanned to automatically adjust the feeding speeds of the sheets which are to be scanned, and the sheet feeding method applied in the image scanning device for realizing successfully feeding the sheets which are to be scanned and have different thicknesses to complete scanning the sheets effectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference toFIG. 1,FIG. 2andFIG. 5, an image scanning device100in accordance with a preferred embodiment of the present invention is shown. The image scanning device100includes an upper shell10, a roller element101, a feeding shaft11, a plurality of springs20, a contact image sensor30, a motor40and a lower shell50. The roller element101includes a feeding roller12and a sensing roller13.

Referring toFIG. 1toFIG. 6again, the feeding shaft11is pivotally connected to the upper shell10. The feeding roller12is fastened to and mounted around the feeding shaft11, and the feeding roller12projects beyond a bottom surface of the upper shell10. A diameter of the sensing roller13is the same as a diameter of the feeding roller12. An outer surface of the sensing roller13is white. The sensing roller13is fastened to and mounted around the feeding shaft11, and the sensing roller13is located adjacent to one side of the feeding roller12. The sensing roller13is spaced from the one side of the feeding roller12. The motor40is connected with the feeding shaft11. The motor40drives the feeding shaft11to rotate in different speeds and bring along the feeding roller12and the sensing roller13to rotate simultaneously. The motor40drives roller element101to rotate in the different speeds by virtue of the feeding shaft11. The motor40drives the feeding roller12and the sensing roller13to rotate in the different speeds by virtue of the feeding shaft11.

The lower shell50is pivotally covered to the upper shell10. The plurality of the springs20are mounted to the lower shell50and are capable of stretching and retracting upward and downward with respect to the feeding shaft11. The contact image sensor30is mounted to the plurality of the springs20and is capable of moving upward and downward with respect to the feeding shaft11. A top surface of the contact image sensor30faces to a lower portion of an outer surface of the roller element101, and the top surface of the contact image sensor30is capable of abutting against the lower portion of the outer surface of the roller element101by virtue of the plurality of the springs20elastically abutting against a bottom surface of the contact image sensor30. The top surface of the contact image sensor30faces to lower portions of outer surfaces of the feeding roller12and the sensing roller13, and the top surface of the contact image sensor30is capable of abutting against the lower portions of the outer surfaces of the feeding roller12and the sensing roller13by virtue of the plurality of the springs20elastically abutting against the bottom surface of the contact image sensor30.

The contact image sensor30includes a bracket31, glass32, a light guide element34, a plurality of self-focusing lenses35and a light receiving element36. The bracket31is of a U shape. The bracket31is capable of being mounted to the plurality of the springs20and moving upward and downward. The glass32is disposed to a top surface of the bracket31. A top surface of the glass32is capable of abutting against the lower portion of the outer surface of the roller element101. The top surface of the glass32is capable of abutting against the lower portions of the outer surfaces of the feeding roller12and the sensing roller13. The bracket31cooperates with the glass32to form a receiving chamber33inside the bracket31.

The light guide element34is received in the receiving chamber33and located under the glass32. The light guide element34emits linear light penetrating through the glass32to the outer surfaces of the feeding roller12and the sensing roller13. The plurality of the self-focusing lenses35are received in the receiving chamber33and arranged transversely, and the plurality of the self-focusing lenses35are located under the glass32. The light receiving element36is received in the receiving chamber33and located under the plurality of the self-focusing lenses35. The light receiving element36receives reflected light from the outer surfaces of the feeding roller12and the sensing roller13by virtue of the corresponding plurality of the self-focusing lenses35. So a distance between the outer surface of the roller element101and the top surface of the glass32is judged according to brightness variations of images of the outer surface of the roller element101.

Referring toFIG. 1toFIG. 7, a sheet feeding method applied in the image scanning device100in accordance with the present invention for scanning sheets200is shown. Specific steps of the sheet feeding method are described as follows.

Firstly, before scanning, torsions of the motor40are enough to bring along all kinds of the sheets200, each of the sheets200which are to be scanned is brought under the feeding roller12and the sensing roller13in a low speed, and each of the sheets200which are to be scanned is stopped to the top surface of the glass32of the contact image sensor30. The image scanning device100proceeds with automatically detecting a thickness of each of the sheets200which are to be scanned according to a depth of intensity (DOI) principle.

Specifically, drive each of the sheets200which are to be scanned to be fed forward to a preset position by virtue of the feeding roller12of the roller element101rotating, each of the sheets200which are to be scanned pushes against the contact image sensor30to move downward, the plurality of the springs20are compressed, an interval is formed between the lower portion of the outer surface of the roller element101and the top surface of the contact image sensor30. Specifically, the interval is formed between the lower portion of the outer surface of the roller element101and the top surface of the glass32of the contact image sensor30. In the preferred embodiment, the interval is formed between the lower portions of the outer surfaces of the feeding roller12and the sensing roller13, and the top surface of the contact image sensor30. Specifically, the interval is formed between the lower portions of the outer surfaces of the feeding roller12and the sensing roller13, and the top surface of the glass32of the contact image sensor30.

Secondly, read image read values of the outer surface of the roller element101, and the contact image sensor30records the image read values of the outer surface of the roller element101at different intervals (namely different distances) of which each is between the outer surface of the roller element101and the top surface of the contact image sensor30, confirm the distances of which each is between the outer surface of the roller element101and the top surface of the contact image sensor30according to the image read values of the outer surface of the roller element101, namely thicknesses of the fed sheets200which are to be scanned. In the preferred embodiment, read image read values of the outer surface of the sensing roller13, the contact image sensor30records the image read values of the outer surface of the sensing roller13at the different intervals (namely the different distances) of which each is between the outer surfaces of the feeding roller12and the sensing roller13, and the top surface of the contact image sensor30, confirm the distances of which each is between the outer surfaces of the feeding roller12and the sensing roller13, and the top surface of the contact image sensor30according to the image read values of the outer surface of the sensing roller13, namely the thicknesses of the fed sheets200which are to be scanned.

In the preferred embodiment, the contact image sensor30records the image read values of the outer surface of the sensing roller13at the different intervals (namely the different distances) of which each is between the outer surfaces of the feeding roller12and the sensing roller13, and the top surface of the contact image sensor30and which are 0.7 mm below and 0.7 mm above, so that a preset image read value is set and the preset image read value is distinguished from two thicknesses corresponding to the distances of being 0.7 mm below and 0.7 mm above. The preset image read value is (202).

Thirdly, according to the different intervals of which each is between the outer surface of the roller element101and the top surface of the contact image sensor30, different feeding speeds are separately set corresponding to rotation speeds of the motor40driving the feeding shaft11to bring along the roller element101. The different feeding speeds include two feeding speeds corresponding to two intervals of which each is between the outer surface of the roller element101and the top surface of the contact image sensor30. Specifically, according to the different intervals of which each is between the outer surfaces of the feeding roller12and the sensing roller13, and the top surface of the contact image sensor30, the different feeding speeds are separately set corresponding to the rotation speeds of the motor40driving the feeding shaft11to bring along the feeding roller12and the sensing roller13. In the preferred embodiment, the different feeding speeds include the two feeding speeds corresponding to the two intervals of which each is between the outer surfaces of the feeding roller12and the sensing roller13, and the top surface of the contact image sensor30. One of the two feeding speeds is to feed each of the sheets200which are to be scanned in a high speed, namely the motor40drives the feeding shaft11to bring along the feeding roller12and the sensing roller13to rotate in the high speed. The other feeding speed is to feed each of the sheets200which are to be scanned in the low speed, namely the motor40drives the feeding shaft11to bring along the feeding roller12and the sensing roller13to rotate in the low speed.

When one of the image read values of the outer surface of the roller element101is more than or equal to the preset image read value, namely one of the intervals of which each is between the outer surface of the roller element101and the top surface of the contact image sensor30is denoted to be smaller, one of the sheets200which are to be scanned is thinner, choose feeding the one of the sheets200which are to be scanned in the high speed so as to keep proceeding with scanning in a higher scanning speed. When the one of the image read values of the outer surface of the roller element101is smaller than the preset image read value, namely the one of the intervals of which each is between the outer surface of the roller element101and the top surface of the contact image sensor30is denoted to be larger, the one of the sheets200which are to be scanned is thicker, a problem of lacking of torsion will be caused to make the one of the sheets200which are to be scanned have no way of being fed forward to proceed with scanning the one of the sheets200which are to be scanned, at the moment, the low speed is chosen to feed the one of the sheets200which are to be scanned, so that the one of the sheets200which are to be scanned is ensured to be fed forward. The best feeding speed is automatically adjusted under a limited power supply to feed each of the sheets200which are to be scanned successfully.

In the preferred embodiment, when one of the image read values of the outer surface of the sensing roller13is more than or equal to the preset image read value which is (202), namely the one of the intervals of which each is between the outer surfaces of the feeding roller12and the sensing roller13, and the top surface of the contact image sensor30is denoted to be smaller, the one of the sheets200which are to be scanned is thinner, choose feeding the one of the sheets200which are to be scanned in the high speed so as to keep proceeding with scanning in the higher scanning speed. When the one of the image read values of the outer surface of the sensing roller13is smaller than the preset image read value which is (202), namely the one of the intervals of which each is between the outer surfaces of the feeding roller12and the sensing roller13, and the top surface of the contact image sensor30is denoted to be larger, the one of the sheets200which are to be scanned is thicker, the problem of lacking of torsion will be caused to make the one of the sheets200which are to be scanned have no way of being fed forward to proceed with scanning the one of the sheets200which are to be scanned, at the moment, the low speed is chosen to feed the one of the sheets200which are to be scanned, so that the one of the sheets200which are to be scanned is ensured to be fed forward. The best feeding speed is automatically adjusted under the limited power supply to feed each of the sheets200which are to be scanned successfully.

Fourthly, according to the thicknesses of the fed sheets200which are to be scanned, automatically choose corresponding feeding speeds to feed the sheets200which are to be scanned so as to proceed with scanning.

Referring toFIG. 1toFIG. 7, a form of two ranges of the image read values of the outer surface of the sensing roller13of the image scanning device100is shown inFIG. 7. When each of the sheets200is a normal A4 paper, namely the thickness of the sheet200is 0.1 mm, one range of the image read values of the outer surface of the sensing roller13is (210-229). When each of the sheets200is a card, namely the thickness of each of the sheets200is 0.8 mm, the other range of the image read values of the outer surface of the sensing roller13is (175-194), so when each of the sheets200is the normal A4 paper, choose feeding each of the sheets200in the high speed, when each of the sheets200is the card, choose feeding each of the sheets200in the low speed.

In the preferred embodiment, two preferable feeding speeds for feeding the sheets200are included and corresponding to two intervals of which each is between the outer surfaces of the feeding roller12and the sensing roller13, and the top surface of the contact image sensor30, but the feeding speeds for feeding the sheets200are without being limited to the two feeding speeds corresponding to the two intervals of which each is between the outer surfaces of the feeding roller12and the sensing roller13, and the top surface of the contact image sensor30. The most reasonable feeding speeds for feeding the sheets200are capable of being disposed respectively corresponding to the intervals of 0.25 mm and 0.5 mm, namely the thicknesses of 0.25 mm and 0.5 mm. When the thickness of each of the sheets200is 0.25 mm or 0.5 mm, respectively choose the corresponding feeding speed to feed each of the sheets200so as to scan each of the sheets200.

As described above, the image scanning device100applies the sheet feeding method to set the different feeding speeds according to the different intervals of which each is between the outer surfaces of the feeding roller12and the sensing roller13, and the top surface of the contact image sensor30by virtue of the contact image sensor30recording the image read values at the different intervals (namely the different distances) of which each is between the outer surfaces of the feeding roller12and the sensing roller13, and the top surface of the contact image sensor30before scanning. Furthermore, read the image read values of the outer surface of the sensing roller13, confirm the distances of which each is between the outer surfaces of the feeding roller12and the sensing roller13, and the top surface of the contact image sensor30according to the image read values of the outer surface of the sensing roller13, namely the thicknesses of the fed sheets200which are to be scanned, and then according to the thicknesses of the fed sheets200which are to be scanned, automatically choose corresponding feeding speeds to feed the sheets200which are to be scanned so as to proceed with scanning. As a result, the image scanning device100is capable of automatically detecting the thicknesses of the sheets200which are to be scanned to automatically adjust the feeding speeds of the sheets200which are to be scanned, and the sheet feeding method applied in the image scanning device100for realizing successfully feeding the sheets200which are to be scanned and have different thicknesses to complete scanning the sheets200effectively.