Abstract:
A document feeding system is disclosed in this present invention. The document feeding system according to this invention can improve the document transfer by employing a carrying device with multiple rotating speeds. Thus the mistakes during the document transfer, such as terminating the document transfer, destroying the document, can be prevented by the above-mentioned document feeding system. Moreover, because an accurate calculation in the disposition of elements in the document feeding system is not necessary, the manufacturing of the above-mentioned document feeding system is simpler than the manufacturing of the document feeding system in the prior art. Hence, this invention can not only improve the efficiency of a document transfer, but also simplify the manufacturing process of a document feeding system.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This present invention relates to a document feeding system, and more particularly, to a document feeding system comprising a carrying device with multiple rotating speeds.  
           [0003]    2. Description of the Prior Art  
           [0004]    Document feeding systems are very useful systems. The documents can be fed into a photographic device in turn by employing a document feeding system. Particularly, when a photographic device has to capture lots of images from documents, a document feeding system is very helpful and efficient.  
           [0005]    In the prior art, a document system at least comprises a first roller for picking-up the documents, and a second roller for transferring the documents forward and feeding them into a photographic device. In the prior art, the placement of components is of the utmost importance in order to prevent a jam during any document transfer. The disposition relationship between the first and second roller, and the first roller gear drive has to be accurately calculated. For instance, in the prior art, if the disposition of elements in a document feeding system in the prior art is not calculated accurately, the following mistake might occur. The drawing force on the first roller may be terminated when the front of a document is past the second roller and the rear of the document still hasn&#39;t passed the first roller.  
           [0006]    In other words, to efficiently prevent a mistake in a document feeding system during a document transfer, the disposition of elements in the above-mentioned document feeding system has to be accurately calculated from the beginning. However, in constructing a document feeding system, it&#39;s a complex process to calculate the disposition of the elements therein.  
           [0007]    Hence, in improving the performance of a document feeding system, it&#39;s an important object to provide a document feeding system without an accurate calculation of disposition of every element therein, wherein the document feeding system can prevent mistakes during an efficient document transfer.  
         SUMMARY OF THE INVENTION  
         [0008]    In accordance with the present invention, a document feeding system is provided for document transfer. The document feeding system comprises at least a carrying device with a multiple rotating speed, such that the mistakes in the prior art during a document transfer will not occur in the document feeding system according to this invention.  
           [0009]    It is another object of this invention to simplify the manufacturing of a document feeding system. In the above-mentioned document feeding system, the disposition of elements is not necessary through an accurate calculation, thus the mistakes in the prior art will not occur during a document transfer.  
           [0010]    It is still another object of this present invention to smooth the transfer of a document by employing a carrying device with a multiple rotating speed in a document feeding system, thus the document feeding system performance will be improved.  
           [0011]    In accordance with the above-mentioned objects, the invention provides a document feeding system. The above-mentioned document feeding system comprises at least a first carrying device, and a second carrying device. The first carrying device comprises a first roller, a driving means, and a coupling means. The driving means may be a gear. The coupling means is utilized for connecting the driving means and the first roller. The coupling means may be a one-way spring. The driving means comprises a trench thereon, and the coupling means comprises a protruding portion disposed in the trench, such that the driving means can drive the rotation of the first roller. When the front of a document is in the second carrying device, the second roller in the second carrying device will forward transfer the document at a second speed. Before the rear of the document leaves the first roller, the trench on the driving means provides a buffer space for the coupling means, thus the first roller motion will not be terminated and the document will not be destroyed by the drawing force of the second roller. Therefore, the document feeding system according to this invention can improve the reliability and prevent mistakes in document transfers. Moreover, because an accurate calculation in the disposition of elements in the document feeding system according to this invention is not necessary, this invention can simplify the manufacturing of a document feeding system. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:  
         [0013]    [0013]FIG. 1 is a diagram showing the first carrying device of a document feeding system according in this invention;  
         [0014]    [0014]FIGS. 2A to  2 D are diagrams showing the side-view of the first carrying device according to this presented invention during a document transfer;  
         [0015]    [0015]FIG. 3 depicts an S-type automatic document feeding system applied to a photographic device; and  
         [0016]    [0016]FIG. 4 depicts an U-type automatic document feeding system applied to a photographic device.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]    Some sample embodiments of the invention will now be described in greater detail. Nevertheless, it should be recognized that the present invention can be practiced in a wide range of other embodiments besides those explicitly described, and the scope of the present invention is expressly not limited except as specified in the accompanying claims.  
         [0018]    Then, the components in this application are not shown to scale. Some dimensions are exaggerated to the related components to provide a more clear description and comprehension of the present invention.  
         [0019]    One preferred embodiment of this invention is a structure of a document feeding system. The document feeding system according in this embodiment at least comprises a first carrying device, and a second carrying device. The first carrying device comprises a first roller, a driving means for rotation at a first speed, and a coupling means for connecting the driving means and the first roller. The driving means may be a gear, and the coupling means maybe a one-way spring. The driving means comprises a trench thereon, and the coupling means comprises a protruding portion disposed into the trench. The transfer of a document in the above-mentioned document feeding system will be described as follows.  
         [0020]    First, the first roller and the coupling means are rotated with the driving means at the first speed, and the first roller of the first carrying device pick up. When the front of the document is into the second carrying device, the first roller and the coupling means are rotating with the second roller of the second carrying device at a second speed. The second speed is faster than the first speed. In other words, the first roller and the coupling means are rotating faster than the driving means, such that the protruding portion of the coupling means will start to move from the first end to the second end of the trench.  
         [0021]    Subsequently, the transfer of the document continues to the second carrying device. When the protruding portion of the coupling means is attached to the second end of the trench, the rotating speed of the coupling means is equal to the rotating speed of the driving means. In this manner, the rotating speed of the first roller is faster than the rotating speed of the driving means and the coupling means.  
         [0022]    Finally, when the rear of the document has left the first roller, the speed of the first roller and the coupling means will be at zero, and the protruding portion of the coupling means will start to move from the second end to the first end of the trench. When the protruding portion of the coupling means is attached to the first end of the trench, the coupling means and the first roller will be rotating with the driving means at the first speed, and the first roller picks up another document. Next, the above-mentioned document transfer process is repeated.  
         [0023]    In this present embodiment, when the front of a document is fed into the second carrying device, while the rear of the document is still at the first roller of the first carrying device, the driving means trench provides a buffer space. Thus the coupling means keeps the first roller in motion for preventing transfer termination or destroying the document. Moreover, an accurate calculation in the disposition of elements in the document feeding system, according to this embodiment, is not necessary as mentioned in the prior art. Therefore, the manufacturing of the document feeding system according to this embodiment is simpler than the manufacturing of the document feeding system in the prior art.  
         [0024]    Another preferred embodiment of this present invention is a structure of a document feeding system. The document feeding system at least comprises a first carrying device and a second carrying device. FIG. 1 is a diagram showing the first carrying device of a document feeding system according to this embodiment. Referring to FIG. 1, the first carrying device  100  comprises an axle  120 , a roller  140 , a coupling means  160 , and a driving means  180 . The axle  120  is employed as a bearing for the roller  140 , the coupling means  160 , and the driving means  180 . The roller  140  can pick up the documents one by one. The driving means  180  is rotating at a first speed during a document transfer. The coupling means  160  is utilized for connecting the roller  140  and the driving means  180 . The coupling means  160  may be a one-way spring. The driving means  180  may be a gear.  
         [0025]    [0025]FIG. 2A is a side-view of the first carrying device according to this embodiment. As shown in FIG. 2A, the gear  180  comprises a trench  182  thereon. The spring  160  comprises a protruding portion  185  disposed in the trench  182 . The length of the trench  182  is related to the length of the transferred document. Generally speaking, in this embodiment, the transfer of a document from the first carrying device to the second carrying device can be defined in the following four steps. In the first step, the gear  180 , the spring  160 , and the roller  140  are rotated at a first speed, thus the roller  140  of the first carrying device  100  picks up a document. The direction of the rotation is shown by an arrow in the figure. During the first process, the protruding portion  165  of the spring  160  is at the first end  184  of the trench  182 .  
         [0026]    When the front of the document arrives at the second carrying device, the second step has begun. In the second step, because the front of the document is pulled forward by the second carrying device at a second speed, the roller  140  and the spring  160  will be rotated at the second speed. When the roller  140  and the spring  160  are rotated at the second speed, the gear  180  is still rotated at the first speed. In other words, the speed of the roller  140  and the spring  160  is faster than the speed of the gear  180  during the second step. In this manner, the protruding portion  165  of the spring  160  is removed from the first end  184  to the second end  186  of the trench  182 , as shown in FIG. 2B.  
         [0027]    Referring to FIG. 2C, the third step has begun from the protruding portion  165  of the spring  160  attached to the second end  186  of the trench  182 . In the third step, both the spring  160  and the gear  180  are rotating at the first speed. During the third step, the front of the document is past the second carrying device, and the rear of the document is still in the first carrying device. Because the document has not left roller  140  yet, the roller  140  is rotating at the second speed. Therefore, in the third step, the speed of the roller  140  is faster than the speed of the spring  160  and gear  180 .  
         [0028]    After the rear of the document leaves roller  140 , the document transfer goes into the fourth step. Because the document has completely left the roller  140 , the speed of the roller  140  and spring  160  are at a third speed, slower than the first speed, until the protruding portion  165  of the spring  160  attached to the first end  184  of the trench  182 , as shown in FIG. 2D. The third speed may be zero. During the fourth step, the gear  180  is still rotated at the first speed. That is, the speed of the gear  180  is faster than the speed of the roller  140  and spring  160  during the fourth step. Furthermore, while the protruding portion  165  of the spring  160  is attached to the first end  184  of the trench  182 , the above-mentioned steps, from the first step to the fourth step, will be performed again and another document is picked up by the roller  140 .  
         [0029]    Another preferred embodiment according to this present invention is an S-type automatic document feeding system. FIG. 3 depicts an S-type automatic document feeding system applied to a photographic device. The photographic device may be a scanner. Referring to FIG. 3, the S-type automatic document feeding system comprises a paper-in region  310 , a separated roller  320 , a first feeding roller  330 , a first idle roller  340 , a second feeding roller  350 , a second idle roller  360 , and a paper-out region  370 . After the output of a document from the paper-out region  370 , the scanner  300  will begin to scan the document. In this embodiment, the design of the above-mentioned first carrying device  100 , as disclosed in FIG. 1, may be used on the separated roller  320 . Therefore, the document transfer from the separated roller  320  to the first feeding roller  330  can be improved by the above-mentioned steps shown from FIG. 2A to FIG. 2D.  
         [0030]    In another case, the design of the above-mentioned first carrying device  100  may be applied to the first feeding roller  330 . In still another case, the design of the above-mentioned first carrying device  100  may be applied to the separated roller  320  and the first feeding roller  330 . Therefore, the S-type automatic document feeding system according to this embodiment can avoid the disadvantages in the prior art, and the document transfer will become smoother.  
         [0031]    Another preferred embodiment according to this invention is an U-type automatic document feeding system. Referring to FIG. 4, U-type document feeding system is applied to a photographic device. The photographic device may be a scanner. The U-type document feeding system comprises a paper-in region  410 , a pick-up roller  420 , a separated roller  430 , a first feeding roller  440 , a first idle roller  450 , a second feeding roller  460 , a second idle roller  470 , a third feeding roller  480 , and a paper-out region  490 . When a document is output from the paper-out region  490 , the document is in the photographic device, and the photographic device will perform an image-capturing process from the document. In this embodiment, the design of the above-mentioned first carrying device  100  may be applied to at least one of the pick-up roller  420 , the separated roller  430 , the first feeding roller  440 , and the second feeding roller  460 .  
         [0032]    In one case, the pick-up roller  420  may employ the design of the above-mentioned first carrying device  100 . In another case, the design of the first carrying device  100  may be applied to the separated roller  430 . In still another case, the technology of the first carrying device  100  may be applied to both of the pick-up roller  420  and the separated roller  430 . In still another case, the technology of the first carrying device  100  may be applied to the first feeding roller  440  or the second feeding roller  460 . In still another case, the technology of the first carrying device  100  may be applied to the pick-up roller  420 , the separated roller  430 , and the first feeding roller  440 . In still another case, the technology of the first carrying device  100  may be applied to the pick-up roller  420 , the separated roller  430 , the first feeding roller  440 , and the second feeding roller  460  of the U-type document feeding system. According to this embodiment, the U-type document feeding system can prevent the mistakes occurring on the rollers during feeding a document, such as terminating the document transfer, destroying the document. Thus, the performance of a U-type document feeding system according to this embodiment can be improved.  
         [0033]    According to the preferred embodiments, this invention discloses a document feeding system. The above-mentioned document feeding system comprises at least a first carrying device, and a second carrying device. In this present invention, the carrying device comprises a roller, a driving means, and a coupling means for connecting the roller and the driving means. The coupling means maybe a one-way spring. The driving means comprises a trench thereon, and the coupling means comprises a protruding portion disposed into the trench. When a document is transferred between the roller and the second carrying device, the trench provides a buffer zone for keeping the working of the roller. Therefore, the document feeding system according to this present invention can efficiently prevent the mistakes in the prior art occurring during the document transfer. That is, the performance of the document feeding system according to this invention can be improved. Furthermore, an accurate calculation in the disposition of elements in the document feeding system according to this invention is not necessary as mentioned in the prior art. Thus, the manufacturing of the document feeding system according to this invention will be more simpler than the manufacturing of the document feeding system in the prior art.  
         [0034]    Although specific embodiments have been illustrated and described, it will be obvious to those skilled in the art that various modifications may be made without departing from what is intended to be limited solely by the appended claims.