Abstract:
The present invention discloses a flatbed scanner that utilizes a single dynamic source to support dynamic for both the light source projection device and the image generation device. The dynamic generated by the single dynamic source is respectively dispatched to the light source projection device and the image generation device through two separate transmission paths for scanning.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a flatbed scanner, and more particularly, to a flatbed scanner that uses a single dynamic source to support dynamic for both the light projection device and the image pick-up device of the flatbed scanner. 
     2. Description of the Prior Art 
     Nowadays, kinds of scanners are broadly used in computers. Some scanners can scan reflective documents by feeding the reflective documents into the scanners themselves, however, transparent documents only can be scanned through the assistant devices of the scanners. A convenient way for scanning both of the transparent and reflective documents is to apply flatbed scanners. Accordingly, after the transparent documents are put at the top of the transparent windows of the flatbed scanners, the transparent documents can thus be scanned through the cooperation of both the light source and the image generation devices. 
     FIG. 2 depicts the cross section of a conventional flatbed scanner  20  that is composed of an upper portion  201  and a lower portion  202  for cooperatively scanning a scanned document  218 . The upper portion  201  and a lower portion  202  are fastened by using a connection apparatus  219 , and the scanned document  218  can be a transparent document such as a projection slide or a lantern slide. When scan operations start, the dynamic generated by the motor  208  of the upper portion  201  will be transferred through gear sets  207 , a pulley  203 , and a transmission belt  204  to drive the light projection device  205 . In addition, a dynamic generated by the motor  216  of the lower portion  202  is transferred through gear sets  215 , a pulley  209 , and transmission belt  210  to drive the image pick-up device  211 . The light projection device  205  further includes a light source  206 . Furthermore, the image pick-up device  211  encompasses a scanning set, which further comprises a light source  212 , mirrors  217 , lenses  213 , and a CCD (Charge-Coupled Device) sensor  214 . As noted, both the light projection device  205  and the image pick-up device  211  move together to scan the scanned document  218  cooperatively. Moreover, the light source  206  is used for scanning the transparent documents, and the light source  212  is used to scan the reflective documents. 
     Evidently, in the flatbed scanner, both of the upper and lower portions respectively need a motor to generated required dynamic. It is obvious that more power consumption and further components are necessary to establish the flatbed scanner  20 , and more controlled lines are also required for controlling the cooperation between the light projection device  205  and the image pick-up device  211 . A need has been arisen to disclose a flatbed scanner, in which less power consumption and fewer required components are needed for controlling the scan operations. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to disclose a flatbed scanner that scans the scanned documents by using less power consumption and fewer required components than the conventional scheme. 
     Accordingly, the invention employs a single dynamic source to generate dynamic for both the light projection device and the image pick-up device of the flatbed scanner. When the dynamic is generated, it is then transferred by gear sets and transferred components to respectively drive the light projection device and the image pick-up device to perform the scan operations. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     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: 
     FIG. 1 depicts a flow chart representative of the path of the dynamic transference according to the invention; 
     FIG. 2 illustrates a cross section of the conventional flatbed scanner when a scanned document is scanned; 
     FIG. 3 is a cross-sectional view of the invention when a scanned document is scanned; and 
     FIG. 4 demonstrates a cross section representative of twist-limited device used in the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Please refer to FIG. 3, which represents the cross section view of the flatbed scanner  30  according to the invention when a scanned document  320  is scanned. Similar to the conventional flatbed scanner, the flatbed scanner  30  includes an upper portion  301  and a lower portion  302 , and a connection apparatus  323  is also used to fasten the upper portion  301  and the lower portion  302 . However, dynamic generated by a motor  317  will be transferred to both the upper portion  301  and a lower portion  302 . 
     A transference flow of the dynamic source force for the upper portion  301  starts from the motor  317 , through gear sets  316 ,  312 , and  308  to drive the gear sets  307 , pulley  303 , and transmission belt  304  to move a light projection device  305 . The light projection device  305  further encompasses a light source  306  for illuminating lights when the scanned document  320  is a transparent document. Besides, the transference flow of the dynamic source force for the lower portion  302  starts from the motor  317 , through gear sets  316 , pulley  309 , and transmission belt  310  to move an image pick-up device  311 . The image pick-up device  311  further encompasses a light source  313 , mirrors  318 , lenses  315 , and a CCD sensor  314  for generating scanned image of the scanned document  320 . As noted, the light source  313  illuminates lights for scanning when the scanned document  320  is a reflective document. Moreover, a sensor  319  is used to detect whether the upper portion  301  and the lower portion  302  are accurately fastened. 
     Obviously, only a single motor  317  is needed to support required dynamic source force for the flatbed scanner  30  without additional components to control the cooperation of the upper portion  301  and the lower portion  302 . Furthermore, another imaging structure such as a CIS (Contact Image Sensor) and a CMOS (Complementary Metal-Oxide-Semiconductor) sensor can be applied in the image pick-up device  311  although a CCD imaging structure is used in the image pick-up device  311 . 
     Some processes are needed before the dynamic outputs for scanning. FIG. 1 illustrates a dynamic transference flow representative of how the dynamic being transferred to the upper portion  301  and the lower portion  302 . When a dynamic generating device  101  is used to generate the dynamic, a rotation speed reducing device  102  must be applied to decrease the rotation speed of the dynamic generating device  101 . Next, a twist-limited device  103  is employed to transfer the dynamic for driving a first dynamic transference device  106  and a second dynamic transference device  104  to back to their origin positions before scanning. Finally, the dynamic from the first dynamic transference device  106  and the second dynamic transference device  104  is respectively employed to drive an image pick-up device  105  and a light projection device  107  to scan the scanned document. 
     In comparison with the FIG. 3, the dynamic generating device  101  is the motor  317 , the first dynamic transference device  106  basically encompasses the gear sets  316 ,  312 ,  308 ,  307 , pulley  303 , and the transmission belt  304 . Further, the second dynamic transference device  104  includes the gear sets  316 , pulley  309 , and the transmission belt  310 . In addition, the image pick-up device  105  is equivalent to the image pick-up device  311 , and the light projection device  107  is the light projection device  305 . 
     Please refer to FIG. 4, which illustrates a cross section representative of the detail diagram of the twist-limited device  103 . In fact, the twist-limited device  103  encompasses a magnetic driving device  321 , and the dynamic is exported through the gear sets  316 . The gear sets  312  and  322  are used to transfer the dynamic to the upper portion  301  when the transference dynamic is less than a magnetic dynamic. In contrast, if the transference dynamic is larger than the magnetic dynamic, such as when the image pick-up device  311  has gone back to its origin position, the magnetic driving device  321  will be departed to protect the mechanical components of the flatbed scanner  30 . 
     It is necessary to include the twist-limited device  103  because the light projection device  107  and the image pick-up device  105  may not stop simultaneously (such as arrive to the origin or destination positions). For example, when one of the aforementioned devices arrives to the destination position than the other, the first arrived device will be suffered because the continuously supporting dynamic still drives the first arrived devices to keep moving if the twist-limited device  103  is absent. However, the twist-limited device  103  can depart the first arrived device to be driven by the dynamic until the other device arrives. 
     In conclusion, the present invention discloses a single dynamic source to generate dynamic for both the light projection device and the image pick-up device. When the dynamic is generated, it is then transferred by gear sets, transferred components, and pulleys to respectively drive the light projection device and the image pick-up device. 
     As is understood by a person skilled in the art, the foregoing preferred embodiments of the present invention are illustrated of the present invention rather than limiting of the present invention. It is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, the scope of which should be accorded the broadest interpretation so as to encompass all such modifications and similar structure.