Abstract:
An image scanner having wireless carriage module is provided to overcome the abrasion problem occurred between the flat flexible cable and the transparent scanning platform. The image scanner includes a casing; a carriage module disposed inside the casing for picking up image data of an object to be scanned and converting the image data into digital data; a wireless transmitter incorporated into the carriage module for receiving and modulating the digital data into wireless signals and transmitting the wireless signals out; and a wireless receiver separate from the carriage module and being in communication with a processing system for receiving and demodulating the wireless signals from the wireless transmitter into the digital data and outputting the digital data to the processing system for further processing.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to an image scanner, and more particularly to an image scanner having a wireless carriage module.  
       BACKGROUND OF THE INVENTION  
       [0002]     A flat flexible cable (FFC) is a common connecting wire between electric devices. It is advantageous to be easily and reversibly bent and stretched in a narrow and crowded space. For example, in a flatbed image scanner, the moving-around carriage module containing therein optical and photoelectric devices is connected with the circuit board through a flat flexible cable. Please refer to  FIGS. 1A and 1B  which are top and cross-sectional side views, respectively, schematically showing the connecting operation of a flat flexible cable in a flatbed image scanner. The flatbed image scanner  1  includes an upper cover (not shown) and a lower casing  10 . In the lower casing  10 , a carriage module  11  containing therein optical and photoelectric devices, a driving device consisting of a motor and gear set  121  and a rail set  122 , a circuit board  13  including various electronic elements and electrically connected to a computer system  2  via a cable  16 , and a flat flexible cable  14  connecting the carriage module  11  with the circuit board  13  are sealed under a transparent scanning platform  15 . The carriage module  11  is moved by the motor and gear set  121  along the rail set  122  to pass by and scan a document or picture placed on the transparent scanning platform  15  so as to realize the image data of the document or picture.  
         [0003]     Please refer to  FIG. 2A  which is a schematic cross-sectional diagram showing the structure of a conventional flat flexible cable. The flat flexible cable  14  includes a flexible copper foil  141 , an insulating wrapper  142  made of a flexible plastic, and a strengthening plate  143  made of a rigid plastic. The insulating wrapper  142  surrounds the flexible copper foil  141  with two ends of the flexible copper foil  141  exposed for electric contact with the carriage module  11  and the circuit board  13 , respectively. The strengthening plate  143  is mounted onto the end portion of the flat flexible cable  14  to facilitate the insertion of the exposed copper foil into the connecting slot (not shown) of the carriage module  11  or the circuit board  13 . Further referring to  FIG. 1B  again, a portion  145  of the flat flexible cable  14  connecting to the circuit board  13  is fixed on the bottom of the lower casing  10 , and another portion  146  connecting to the carriage module  11  is freely bent and stretched along with the movement of the carriage module  11 .  
         [0004]     During the movement of the carriage module  11 , the flat flexible cable  14  keeps on electrically connecting the carriage module  11  with the circuit board  13  for signal transmission. The configuration of the flat flexible cable  14  changes all the time during the movement of the carriage module  11  along a scanning direction indicated by an arrow C. The distant end  144  of the flat flexible cable  14  from the carriage module  11 , i.e. the U-turn portion, is likely to rise up to the inner surface of the transparent scanning platform  15 , as shown in  FIG. 2B , due to the flexible property thereof. Especially for an image scanner using a contact image sensor (CIS) as an image pickup device which requires close contact with the document on the transparent scanning platform  15 , the flat flexible cable  14  generally keeps in contact with the inner surface of the transparent scanning platform  15  by a part thereof. For example, at a start position where the carriage module  11  is adjacent to the circuit board  13 , the flat flexible cable  14  is bent to have a U-turn point at a position relative to the position A on the transparent scanning platform  15 , as shown in the solid line of  FIG. 1B . On the other hand, at a scanning position where the carriage module  11  moves away from the circuit board  13 , the U-turn position shifts to a position B on the transparent scanning platform  15  along the scanning direction C, as indicated by the dotted line of  FIG. 1B . As a result, abrasion is likely to occur due to the contact of the insulating wrapper  142  of the flat flexible cable  14  with the transparent scanning platform  15  and the movement of the contact point from the position A to the position B. In general, the insulating wrapper  142  is made of a thermoplastic plastic material and the transparent scanning platform  15  is made of glass. As known, a general thermoplastic plastic material has a smaller hardness than the hardness of the transparent scanning platform  15 , so plastic chips may be generated due to the abrasion of the plastic flat flexible cable  14  and the glass scanning platform  15  so as to adversely affect the scanning quality.  
         [0005]     Furthermore, in the above flatbed image scanner, the circuit board  13  is disposed on the bottom of the lower casing  10  and hard to be rearranged because of the physical connection to the carriage module  11  via the flat flexible cable  14 . Therefore, the miniaturization of the image scanner, which is a trend of modern scanners, is difficult to be achieved.  
       SUMMARY OF THE INVENTION  
       [0006]     The present invention provides an image scanner having a wireless carriage module, so no flat flexible cable is required any longer.  
         [0007]     An image scanner for scanning an object to obtain digital data, comprises a casing; a carriage module disposed inside the casing for picking up image data of the object and converting the image data into digital data; a wireless transmitter incorporated into the carriage module for receiving and modulating the digital data into wireless signals and transmitting the wireless signals out; and a wireless receiver separate from the carriage module and being in communication with a processing system for receiving and demodulating the wireless signals from the wireless transmitter into the digital data and outputting the digital data to the processing system for further processing. The image scanner, for example, can be a sheetfed image scanner or a flatbed image scanner.  
         [0008]     According to an embodiment of the present invention, a flatbed image scanner further comprises a power-transmitting medium in electric contact with the carriage module for providing the carriage module with power.  
         [0009]     In an embodiment, the power-transmitting medium comprises two conductive rods extending in parallel along the moving direction of the carriage module and penetrating through the carriage module, the two conductive rods having therebetween voltage difference so as to provide electricity for the carriage module.  
         [0010]     In an alternative embodiment, the power-transmitting medium comprises two conductive plates fixed to the casing and extending along the moving direction of the carriage module, the two conductive plates having therebetween voltage difference so as to provide electricity for the carriage module. Preferably, the power-transmitting medium further comprises two elastic conductor pieces interfacing between the two conductive plates and the carriage module, respectively for stabilizing the movement of the carriage module and avoiding abrasion of the conductive plates. The two conductive plates, for example, can be arranged at the inner bottom of the casing, the same inner side wall of the casing or opposite inner side walls of the casing.  
         [0011]     In an alternative embodiment, the power-transmitting medium comprises a conductive rod and a conductive plate extending along the moving direction of the carriage module and arranged at opposite sides of the carriage module, and there is voltage difference between the conductive rod and the conductive plate so as to provide electricity for the carriage module. The carriage module slidably engages with the conductive rod in a manner that the carriage module keeps in electric contact with the conductive plate while moving along the conductive rod.  
         [0012]     According to the present invention, the power-transmitting medium is a power supply for providing the carriage module with power. In an embodiment, the power supply comprises a battery device coupled to and moving with the carriage module for providing electricity for the carriage module and having first exposed contacts; and a charging device fixed on an inner wall of the casing and having second exposed contacts. The first exposed contacts of the battery device are in electric contact with the second exposed contacts of the charging device when the carriage module is in a standby position so as to receive electricity from the charging device when the image scanner is powered on.  
         [0013]     For example, the wireless transmitter and the wireless receiver comply with a wireless access protocol selected from the group consisting of Bluetooth, IEEE 802.11b and IrDA.  
         [0014]     For example, the wireless receiver is separate from the casing of the image scanner and in communication with the processing system via a universal serial bus (USB) cable or an IEEE 1394 bus cable.  
         [0015]     For example, the wireless receiver is mounted inside the casing of the image scanner and in communication with the processing system via a universal serial bus cable (USB) or an IEEE 1394 bus cable.  
         [0016]     For example, the wireless transmitter and the wireless receiver are implemented with two wireless transceivers. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]     The present invention may best be understood through the following description with reference to the accompanying drawings, in which:  
         [0018]      FIGS. 1A and 1B  are top and cross-sectional side views, respectively, schematically showing the connecting operation of a flat flexible cable in a flatbed image scanner;  
         [0019]      FIG. 2A  is a schematic cross-sectional diagram showing the structure of a conventional flat flexible cable;  
         [0020]      FIG. 2B  is a cross-sectional side diagram showing the abrasion occurred between the flat flexible cable and the transparent scanning platform in the flatbed image scanner;  
         [0021]      FIG. 3A  is a perspective diagram showing a preferred embodiment of a flatbed image scanner according to the present invention;  
         [0022]      FIG. 3B  is a perspective diagram showing another preferred embodiment of a flatbed image scanner according to the present invention;  
         [0023]      FIG. 3C  is a schematic diagram showing a preferred embodiment of a sheetfed image scanner according to the present invention;  
         [0024]     FIGS.  4 A˜ 4 C are schematic diagrams showing three preferred embodiments of power-transmitting method for providing the wireless carriage module of the flatbed image scanner with power according to the present invention; and  
         [0025]      FIGS. 5A and 5B  are perspective diagrams showing further preferred embodiments of a flatbed image scanner according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0026]     The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only; it is not intended to be exhaustive or to be limited to the precise form disclosed.  
         [0027]     Please refer to  FIG. 3A  which is a perspective diagram showing a preferred embodiment of a flatbed image scanner according to the present invention. A processing system is implemented with a computer system  2  in this and subsequent embodiments. The flatbed image scanner  5  includes a cover (not shown) and a lower casing  51  in which a carriage module  54 , two conductive rods  52  and  53 , and a wireless transmitter  7  is disposed. The wireless transmitter  7  is incorporated into the carriage module  54 , and a wireless receiver  3  corresponding to the wireless transmitter  7  is separate from the carriage module  54 . The two conductive rods  52  and  53  made of metal extend in parallel along the moving direction of the carriage module  54  and penetrate through the carriage module  54  to be in electric contract with the inner circuits (not shown) of the carriage module  54 . The carriage module  54  also slidably engages with and moves along the conductive rods  52  and  53 . When the flatbed image scanner  5  is powered on, the two conductive rods  52  and  53  electrically connected to a power source (not shown) have therebetween voltage difference to provide electricity for both the carriage module  54  and the wireless transmitter  7  incorporated into the carriage module  54 . While scanning, the carriage module  54  slides along the conductive rods  52  and  53  and picks up image data of the document or picture placed on the transparent scanning platform. The image data is then converted into digital data by the carriage module  54 . After the wireless transmitter  7  receives the digital data, it modulates the digital data into wireless signals and transmits the wireless signals out. The wireless receiver  3  located outside the casing  51  receives the wireless signals and demodulating them into the digital data to be outputted to the computer system  2  via a cable  21  such as a universal serial bus (USB) cable or an IEEE 1394 bus cable for further processing. Certainly, the wireless transmitter  7  and the wireless receiver  3  should comply with the same wireless access protocol such as Bluetooth, IEEE 802.11b, IrDA, or any other known wireless transmission standard.  
         [0028]     By this way, the conventional flat flexible cable connecting the carriage module to the circuit board is no longer required so the abrasion problem due to the contact between the flat flexible cable and the transparent scanning platform is overcome. Further, the image scanner can be placed according to the user&#39;s demand without the restriction of the length of the cable connecting the conventional image scanner and the computer system.  
         [0029]     Please refer to  FIG. 3B  which is a perspective diagram showing another preferred embodiment of a flatbed image scanner according to the present invention. The flatbed image scanner  6  includes a cover (not shown) and a lower casing  61  in which a carriage module  64 , a power supply including a battery device  63  and a charging device  62 , and a wireless transmitter  7  is disposed. The wireless transmitter  7  is incorporated into the carriage module  64 , and a wireless receiver  3  corresponding to the wireless transmitter  7  separate from the carriage module  64  is located outside the casing  61  of the flatbed image scanner  6 . The battery device  63  is coupled to and moving with the carriage module  64 , and the charging device  62  is fixed on an inner wall of the casing  61 . Both the battery device  63  and the charging device  62  have two exposed contacts  63   a ,  63   b ,  62   a ,  62   b , respectively. When the flatbed image scanner  6  is powered on and the carriage module  64  is in a standby position, the exposed contacts  63   a  and  63   b  of the battery device  63  are in electric contact with the exposed contacts  62   a  and  62   b  of the charging device  62 . At the moment, the charging device  62  charges the battery device  63  so that the battery device  63  can receive enough electricity for the carriage module  64  and the wireless transmitter  7  to proceed to the following scanning operation. While scanning, the carriage module  64  moves and picks up image data of the document or picture to be scanned. The image data is then converted into digital data by the carriage module  64 . After the wireless transmitter  7  receives the digital data, it modulates the digital data into wireless signals and transmits the wireless signals out. The wireless receiver  3  located outside the casing  61  receives the wireless signals and demodulating them into the digital data to be outputted to the computer system  2  via a cable  21  for further processing.  
         [0030]     In another embodiment, the wireless transmission is applied to a sheetfed image scanner  4 . Please refer to  FIG. 3C  which is a schematic diagram showing a preferred embodiment of a sheetfed image scanner according to the present invention. The wireless transmitter  7  is incorporated into the carriage module  41  and the corresponding wireless receiver  3  is separate from the carriage module  41 . While scanning, the document or picture  8  to be scanned is fed into the sheetfed image scanner  4  and transported by the rollers  80  to pass the scanning passage  81 . The fixed carriage module  41  picks up image data of the moving document  8  and converts the image data into digital data. After the wireless transmitter  7  receives the digital data, it modulates the digital data into wireless signals and transmits the wireless signals out. The wireless receiver  3  receives the wireless signals and demodulating them into the digital data to be outputted to the computer system  2  via a cable  21  for further processing.  
         [0031]     FIGS.  4 A˜ 4 C are schematic diagrams showing three preferred embodiments of power-transmitting method for providing the wireless carriage module of the flatbed image scanner with power according to the present invention. In these schematic diagrams, the size of the carriage module  54  is enlarged to explain the structure of the power-transmitting medium and does not agree with the exact proportion. In  FIG. 4A , the power-transmitting medium includes two conductive rods  52  and  53  penetrating the carriage module  54  as described in the preceding paragraph with reference to  FIG. 3A . In another embodiment as shown in  FIG. 4B , the power-transmitting medium includes a conductive rod  52  and a conductive plate  52   a  extending along the moving direction of the carriage module  54 . The conductive rod  52  and the conductive plate  52   a  are arranged at opposite sides of the carriage module  54 . When the flatbed image scanner  5  is powered on, there is voltage difference between the conductive rod  52  and the conductive plate  52   a  so as to provide electricity for the carriage module  54  and the wireless transmitter  7 . An elastic conductor piece  55  may be provided to interface between the conductive plate  52   a  and the carriage module  54  for stabilizing the movement of the carriage module  54  and avoiding abrasion of the conductive plate  53   a  due to the movement of the carriage module  54  along the conductive rod  52 . In an alternative embodiment, the power-transmitting medium includes two conductive plates  52   a  and  53   a  fixed to the casing and extending along the moving direction of the carriage module  54  as shown in  FIG. 4C . The two conductive plates  52   a  and  53   a  have therebetween voltage difference when the flatbed image scanner  5  is powered on so as to provide electricity for the carriage module  54 . There is no electricity passing through the rod  521 , and the rod  521  only serves as a tracking rail of the carriage module  54 . Two elastic conductor pieces  55  may be provided to interface between the carriage module  54  and the two conductive plates  52   a  and  53   a , respectively, for stabilizing the movement of the carriage module  54  and avoiding abrasion between the carriage module  54  and the conductive plates  52   a  and  53   a . The conductive plates  52   a  and  53   a  may be arranged at the inner bottom of the casing, the same inner side wall of the casing, or opposite inner side walls of the casing according to the designer&#39;s options and considerations. The elastic conductor pieces  55  can be implemented with resilient pieces or wires.  
         [0032]     Please refer to  FIGS. 5A and 5B  which are perspective diagrams showing further preferred embodiments of a flatbed image scanner according to the present invention. In these embodiments, the wireless receiver  3  is respectively disposed in the casings  51  and  61  of the flatbed image scanners  5  and  6 . The wireless receiver  3  is in communication with the computer  2  via a cable  21 . No flat flexible cable is required in the flatbed image scanner containing therein the wireless transmitter  7  and the wireless receiver  3 .  
         [0033]     Alternatively, the wireless transmitter  7  and the wireless receiver  3  can be implemented with two wireless transceivers. As described above, the transmission is performed by the way that the first wireless transceiver substituted for the wireless transmitter  7  will convert the digital data from the carriage module into wireless signals (modulated digital data) and transmits them out, and than the second wireless transceiver substituted for the wireless receiver  3  receives the wireless signals (modulated digital data) and converted them into the digital data for further processing by the computer system  2 . In this embodiment, an additional transmission is performed in the following steps. At first, the computer system  2  outputs a control signal to the second wireless transceiver. The second wireless transceiver converts the control signal into a wireless signal (modulated control signal) and transmits it out. Then the first wireless transceiver receives and demodulates the wireless signal (modulated control signal) into the control signal for controlling the scanning operation of the carriage module. The bidirectional transmission implemented by adopting wireless transceivers makes the image scanner more powerful.  
         [0034]     As described above, the image scanner including a wireless carriage module according to the present invention can eliminate the physical connection to the carriage module via the flat flexible cable. Therefore, the structure is helpful to miniaturize the image scanner to cater for the current trend.  
         [0035]     While the invention has been described in terms of what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention need 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.