Patent Publication Number: US-2012038728-A1

Title: Printing device with marking function

Description:
FIELD OF THE INVENTION 
     The present invention relates to a printing device, and more particularly to a printing device with a marking function. 
     BACKGROUND OF THE INVENTION 
     Printing devices are peripherals for printing characters and/or graphics on papers or other kinds of printing media. Generally, the printing devices are classified into two types: ordinary printing devices and thermal transfer printing devices. 
     The configurations of the thermal transfer printing devices are substantially identical to those of the ordinary printing devices except for the way of printing on the media. For example, the ordinary printing device supplies ink or toner onto a paper. Whereas, a thermal transfer printing device uses a thermal print head (TPH) to heat a ribbon to allow the coating of the ribbon to be adsorbed on a transfer paper. The common thermal transfer printing devices include for example faxing machines, the POS (Point of Sale) printers and barcode printers. 
     The conventional thermal transfer printing devices have been widely used. Among these conventional thermal transfer printing devices, since the barcode printers are usually used to print images on so many barcode papers, the long-term uses of the barcode printers may cause deteriorated printing quality. For checking the printing quality of the barcode paper, the printed barcode papers should be one by one examined with the naked eyes to find the barcode papers that have much inferior printing quality. Since some defective barcode papers fail to be directly examined with the naked eyes, an additional scanning device should be used to examine the barcode papers. In other words, the process of examining the barcode papers is very time-consuming and the process of operating the scanning device is labor-intensive. For solving these drawbacks, it is necessary to develop a thermal transfer printing device having the functions of examining the printing quality and marking the unqualified barcode papers. 
     Recently, a thermal transfer printing device with a marking function has been disclosed and commercially available.  FIG. 1  is a schematic side view illustrating a thermal transfer printing device with a marking function according to the prior art.  FIG. 2  is a schematic side view illustrating the thermal transfer printing device of  FIG. 1  and taken along another viewpoint. Please refer to  FIGS. 1 and 2 . The thermal transfer printing device  1  comprises a casing  10 , a thermal transfer printing module  11 , a first power-providing device  12 , a first gear set  13 , a second power-providing device  14 , a second gear set  15 , a third power-providing device  16 , a transmission mechanism  17 , an external identification module  18  and a controlling unit  19 . The thermal transfer printing module  11  comprises a ribbon transport module  111 , a transfer paper transport module  112 , a thermal print head  113  and a print roller  114 . A ribbon R of the ribbon transport module  111  is transported through the region between the thermal print head  113  and the print roller  114 . Similarly, a transfer paper M of the transfer paper transport module  112  is transported through the region between the thermal print head  113  and the print roller  114 . The transfer paper M comprises a releasing paper part M 1  and a medium part M 2 . The medium part M 2  is disposed over the releasing paper part Ml. The thermal print head  113  is used for heating the ribbon R to allow the coating of the ribbon R to be adsorbed on the medium part M 2  of the transfer paper M. In such way, a thermal transfer printing operation is performed to print the medium part M 2  as a barcode paper M 3 . The print roller  114  is used for transporting the ribbon R and the transfer paper M and facilitating the thermal print head  113  to stably perform the thermal transfer printing operation. 
     As shown in  FIG. 1 , the ribbon transport module  111  comprises a ribbon supplying terminal  1111 , a ribbon recovering terminal  1112 , a first tension shaft  1113  and a second tension shaft  1114 . The ribbon R is stored in the ribbon supplying terminal  1111 . An end of the ribbon R is wound around and the fixed in the ribbon recovering terminal  1112 . Due to the first tension shaft  1113  and the second tension shaft  1114 , a tension force is exerted on the ribbon R. When the ribbon supplying terminal  1111  is driven to rotate, the ribbon R is transmitted from the ribbon supplying terminal  1111  to the ribbon recovering terminal  1112 . The transfer paper transport module  112  comprises a transfer paper supplying terminal  1121 , a transfer paper recovering terminal  1122 , a third tension shaft  1123  and a fourth tension shaft  1124 . The configurations and functions of the transfer paper transport module  112  are very similar to the ribbon transport module  111 . The transfer paper M is stored in the transfer paper supplying terminal  1121 . An end of the transfer paper M is wound around and the fixed in the transfer paper recovering terminal  1122 . Due to the third tension shaft  1123  and the fourth tension shaft  1124 , a tension force is exerted on the transfer paper M. When the transfer paper recovering terminal  1122  is driven to rotate, the transfer paper M is transmitted from the transfer paper supplying terminal  1121  to the transfer paper recovering terminal  1122 . 
     As shown in  FIG. 2 , the external identification module  18  is disposed on the casing  10  and arranged outside the casing  10 . The external identification module  18  is used for scanning the printed barcode paper M 3 . For example, the external identification module  18  is a scanning module. From the relative locations as shown in  FIGS. 1 and 2 , the first gear set  13  is connected with the ribbon recovering terminal  1112 , the second gear set  15  is connected with the transfer paper recovering terminal  1122 , and the transmission mechanism  17  is connected with the print roller  114 . The first power-providing device  12  is connected with the first gear set  13  for providing motive power to the first gear set  13  to drive rotation of the ribbon recovering terminal  1112 . The second power-providing device  14  is connected with the second gear set  15  for providing motive power to the second gear set  15  to drive rotation of the transfer paper recovering terminal  1122 . In addition, the third power-providing device  16  is connected with the transmission mechanism  17  for providing motive power to the transmission mechanism  17  to drive rotation of the print roller  114 . For example, the first power-providing device  12 , the second power-providing device  14  and the third power-providing device  16  are motors. The controlling unit  19  is connected with the first power-providing device  12 , the second power-providing device  14 , the third power-providing device  16  and the external identification module  18  for enabling or disabling the first power-providing device  12 , the second power-providing device  14  and the third power-providing device  16 , and judging whether the printing quality of the barcode paper M 3  is acceptable or unqualified. 
     During operations of the thermal transfer printing device  1 , the first power-providing device  12 , the second power-providing device  14  and the third power-providing device  16  are enabled. As such, the ribbon R is transmitted from the ribbon supplying terminal  1111  to the ribbon recovering terminal  1112 , and the transfer paper M is transmitted from the transfer paper supplying terminal  1121  to the transfer paper recovering terminal  1122 . At the same time, the print roller  114  is rotated. When the transfer paper M is transported through the region between the thermal print head  113  and the print roller  114 , the thermal print head  113  performs a thermal transfer printing operation. In such way, the medium part M 2  of the transfer paper M is printed as a barcode paper M 3 . As the print roller  114  and the transfer paper recovering terminal  1122  are continuously rotated, the releasing paper part M 1  is detached from the barcode paper M 3 . The releasing paper part M 1  is transmitted to the transfer paper recovering terminal  1122 , but the barcode paper M 3  is ejected out of the casing  10 . When the barcode paper M 3  is ejected out of the casing  10 , a light beam B emitted from the external identification module  18  is projected on the barcode paper M 3  to scan the barcode paper M 3 . According to the scanned image of the barcode paper M 3 , the controlling unit  19  will judge whether the scanning quality is acceptable. If the controlling unit  19  judges that the scanning quality is acceptable, the barcode paper M 3  is continuously ejected out of the casing  10  and departed from the thermal transfer printing device  1 . Whereas, if the controlling unit  19  judges that the scanning quality is not acceptable, the controlling unit  19  will control a reverse rotation of the print roller  114 . Upon the reverse rotation of the print roller  114 , the barcode paper M 3  is transmitted to the region between the between the thermal print head  113  and the print roller  114 , and the thermal print head  113  performs a thermal transfer printing operation on the barcode paper M 3 . In such way, an unqualified mark is printed on the barcode paper M 3 . The barcode paper M 3  with the unqualified mark is then ejected to be identified by the user. 
     According to the above operating method of the conventional thermal transfer printing device, the user may identify the scanning quality of the barcode paper by judging whether the barcode paper has any unqualified mark. Although the conventional thermal transfer printing device has the functions of examining the printing quality and marking the unqualified barcode papers, there are still some drawbacks. For example, when the unqualified mark is printed on the unqualified barcode paper by the conventional thermal transfer printing device, the print roller should be controlled to be reversely rotated to have the unqualified barcode paper pass through the thermal print head again. In addition, after the unqualified mark is printed on the unqualified barcode paper, the print roller should be controlled to be normally rotated to eject the unqualified barcode paper. In other words, for printing the unqualified mark by the conventional thermal transfer printing device, the controlling unit should perform precise computation and accurately cooperate with the print roller. For avoiding erroneous operation, the reliability of the conventional thermal transfer printing device should be extremely high. 
     Moreover, since the transfer paper needs to be returned to the location of the thermal print head when the unqualified mark is printed by the conventional thermal transfer printing device, the unqualified mark by the conventional thermal transfer printing device should have plural power-providing device. For avoiding bending the ribbon and transfer paper and eliminating occurrence of the mutual interference between the ribbon and transfer paper, while the transfer paper is returned back to the print roller, the ribbon transfer module and the transfer paper transport module are not moved. However, during the transfer paper is returned back, the transfer paper between the thermal print head and the transfer paper supplying terminal is easily bent to lose the tension force. Under this circumstance, the transfer paper is possibly damage and thus the printing quality is impaired. 
     SUMMARY OF THE INVENTION 
     The present invention provides a printing device with a marking function, which the process of printing a mark is performed without complex control and computation. 
     The present invention also provides a printing device with a marking function, in which the process of producing the unqualified mark is performed without the need of returning back the transfer paper. 
     In accordance with an aspect of the present invention, there is provided a printing device with a marking function. The printing device includes a printing module, an identification module, a power-providing device and a marking member. The printing module is used for performing a printing operation to produce a barcode paper, and transporting the barcode paper. The identification module is disposed beside the printing module, and has a preset barcode image. According to the preset barcode image, the identification module judges whether the barcode paper is identical to the preset barcode image. The power-providing device is connected with the printing module and the identification module for providing motive power to the printing module and the identification module. The marking member is connected with the identification module. If the identification module judges that the barcode paper is different from the preset barcode image, the marking member produces a mark on the barcode paper. The barcode paper is successively transported through the printing module, the identification module and the marking member. 
     In an embodiment, the printing module includes a ribbon transport module, a transfer paper transport module, a thermal print head and a print roller. The ribbon transport module is used for transmitting a ribbon from a ribbon supplying terminal to a ribbon recovering terminal. The transfer paper transport module is used for transmitting a transfer paper from a transfer paper supplying terminal to a transfer paper recovering terminal. The transfer paper includes a releasing paper part and a medium part disposed on the releasing paper part. The thermal print head is arranged between the ribbon transport module and the transfer paper transport module for performing the printing operation on the medium part of the transfer paper through the ribbon, thereby printing the medium part as the barcode paper. The print roller is arranged beside the thermal print head for transporting the transfer paper, so that the transfer paper is transmitted to the identification module. 
     In an embodiment, the ribbon transport module includes a first tension shaft and a second tension shaft. The first tension shaft is arranged between the ribbon supplying terminal and the thermal print head for applying a first tension force to the ribbon. The second tension shaft is arranged between the thermal print head and the ribbon recovering terminal for applying the first tension force to the ribbon. 
     In an embodiment, the transfer paper transport module includes a third tension shaft and a fourth tension shaft. The third tension shaft is arranged between the transfer paper supplying terminal and the thermal print head for applying a second tension force to the transfer paper. The fourth tension shaft is arranged between the thermal print head and the transfer paper recovering terminal for applying the second tension force to the transfer paper. 
     In an embodiment, the printing device further includes a sensor, which is connected with the printing module for detecting a thickness of the transfer paper. When the thickness of the transfer paper detected by the sensor is changed from a first thickness to a second thickness greater than the first thickness, the sensor issues a driving signal to the printing module to enable the printing module. The first thickness is equal to a thickness of the releasing paper part. The second thickness is equal to an overall thickness of the medium part and the releasing paper part. 
     In an embodiment, the identification module includes a scanning element, a controlling unit, a first transport roller assembly and a second transport roller assembly. The scanning element is used for scanning the barcode paper, thereby acquiring a scanned barcode image. The controlling unit is connected with the scanning element, and stores the preset barcode image. By comparing the scanned barcode image with the preset barcode image, the controlling unit judges whether the scanned barcode image is identical to the preset barcode image. The first transport roller assembly is arranged at a first side of the scanning element for transporting the barcode paper through the scanning element. The second transport roller assembly is arranged at a second side of the scanning element for transporting the barcode paper to be departed from the scanning element. 
     In an embodiment, the scanning element is a contact image sensor (CIS). 
     In an embodiment, the marking member includes a marking head and a solenoid valve. The marking head is used for producing a mark on the barcode paper. The solenoid valve is connected with the marking head for moving the marking head upwardly and downwardly with respect to the barcode paper. 
     In an embodiment, the marking head is a seal, a punching head or a trimming knife, and the mark is an unqualified symbol, an opening or a notch. 
     In an embodiment, the printing device further includes a gear set. The gear set is connected with the power-providing device, the printing module and the identification module for receiving the motive power from the power-providing device, and transmitting the motive power to the printing module and the identification module. 
     The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic side view illustrating a thermal transfer printing device with a marking function according to the prior art; 
         FIG. 2  is a schematic side view illustrating the thermal transfer printing device of  FIG. 1  and taken along another viewpoint; 
         FIG. 3  is a schematic side view illustrating the outward appearance of a transfer paper used in a thermal transfer printing device with a marking function according to an embodiment of the present invention; 
         FIG. 4  is a schematic side view illustrating a printing device with a marking function according to an embodiment of the present invention; and 
         FIG. 5  is a schematic side view illustrating the printing device of  FIG. 4  and taken along another viewpoint. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     For obviating the drawbacks encountered from the prior art, the present invention provides a printing device with a marking function.  FIG. 3  is a schematic side view illustrating the outward appearance of a transfer paper used in a thermal transfer printing device with a marking function according to an embodiment of the present invention. As shown in  FIG. 3 , the transfer paper M′ comprises a releasing paper part M 1 ′ and a medium part M 2 ′ disposed on the releasing paper part M 1 ′. The top surface of the medium part M 2 ′ is a blank surface. The bottom surface of the medium part M 2 ′ is coated with an adhesive, so that the medium part M 2 ′ may be adhered to the releasing paper part M 1 ′. As shown in  FIG. 3 , the releasing paper part M 1 ′ has a first thickness T 1 . In addition, the releasing paper part M 1 ′ is stacked on the medium part M 2 ′, and the overall thickness of the transfer paper M′ is equal to a second thickness T 2 . 
     Hereinafter, the configurations of the printing device  2  with a marking function according to the present invention will be illustrated with reference to  FIGS. 4 and 5 .  FIG. 4  is a schematic side view illustrating a printing device with a marking function according to an embodiment of the present invention.  FIG. 5  is a schematic side view illustrating the printing device of  FIG. 4  and taken along another viewpoint. The printing device  2  comprises a printing module  20 , an identification module  21 , a power-providing device  22 , a marking member  23 , a sensor  24  and a gear set  25 . The printing module  20  is used for printing images on the blank medium part M 2 ′ to produce a barcode paper M 3 ′ (i.e. a printed medium part M 2 ′), and transporting the barcode paper M 3 ′. The identification module  21  is arranged beside the printing module  20 . In addition, the identification module  21  has a preset barcode image. According to the preset barcode image, the identification module  21  may judge whether the barcode paper M 3 ′ is identical to the preset barcode image. The power-providing device  22  is connected with the printing module  20  and the identification module  21  for providing motive power to the printing module  20  and the identification module  21 . The marking member  23  is connected with the identification module  21 . In a case that the identification module  21  judges that the barcode paper M 3 ′ is different from the preset barcode image, the marking member  23  produces a mark on the barcode paper M 3 ′. The sensor  24  is connected with the printing module  20  and arranged in the vicinity of the printing module  20  for detecting the thickness of the transfer paper M′. The gear set  25  is connected with the power-providing device  22 , the printing module  20  and the identification module  21  for receiving the motive power from the power-providing device  22 , and transmitting the motive power to the printing module  20  and the identification module  21 . 
     The detailed structures of the components of the printing device  2  will be illustrated as follows. As shown in  FIG. 4 , the printing module  20  comprises a ribbon transport module  201 , a transfer paper transport module  202 , a thermal print head  203  and a print roller  204 . By the ribbon transport module  201 , a ribbon R′ is transmitted from a ribbon supplying terminal  2011  to a ribbon recovering terminal  2012 . By the transfer paper transport module  202 , the transfer paper M′ is transmitted from a transfer paper supplying terminal  2021  to a transfer paper recovering terminal  2022 . The thermal print head  203  is arranged between the ribbon transport module  201  and the transfer paper transport module  202  for printing images on the medium part M 2 ′ of the transfer paper M′ through the ribbon R′. In such way, a thermal transfer printing operation is performed to print the medium part M 2 ′ as the barcode paper M 3 ′. The print roller  204  is arranged beside the thermal print head  203  for transporting the transfer paper M′, so that the barcode paper M 3 ′ of the transfer paper M′ is transmitted to the identification module  21  and the releasing paper part M 1 ′ of the transfer paper M′ is transmitted to the transfer paper recovering terminal  2022 . 
     Please refer to  FIG. 4  again. In addition to the ribbon supplying terminal  2011  and the ribbon recovering terminal  2012 , the ribbon transport module  201  further comprises a first tension shaft  2013  and a second tension shaft  2014 . The first tension shaft  2013  is arranged between the ribbon supplying terminal  2011  and the thermal print head  203  for applying a first tension force to the ribbon R′. The second tension shaft  2014  is arranged between the thermal print head  203  and the ribbon recovering terminal  2012  for applying the first tension force to the ribbon R′. In addition to the transfer paper supplying terminal  2021  and the transfer paper recovering terminal  2022 , the transfer paper transport module  202  further comprises a third tension shaft  2023  and a fourth tension shaft  2024 . The third tension shaft  2023  is arranged between the transfer paper supplying terminal  2021  and the thermal print head  203  for applying a second tension force to the transfer paper M′. The fourth tension shaft  2024  is arranged between the thermal print head  203  and the transfer paper recovering terminal  2022  for applying the second tension force to the transfer paper M′. 
     The identification module  21  comprises a scanning member  211 , a controlling unit  212 , a first transport roller assembly  213  and a second transport roller assembly  214 . The scanning element  211  is used for scanning the barcode paper M 3 ′, thereby acquiring a scanned barcode image. The controlling unit  212  is connected with the scanning element  211 . The preset barcode image is stored in the controlling unit  212 . By comparing the scanned barcode image with the preset barcode image, the controlling unit  212  may judge whether the scanned barcode image is identical to the preset barcode image. In this embodiment, the scanning element  211  is a contact image sensor (CIS), and the controlling unit  212  is a microprocessor. The first transport roller assembly  213  is arranged at a first side of the scanning element  211  for transporting the barcode paper M 3 ′ through the scanning element  211 . The second transport roller assembly  214  is arranged at a second side of the scanning element  211  for transporting the barcode paper M 3 ′ to be departed from the scanning element  211 . 
     The marking member  23  comprises a marking head  231  and a solenoid valve  232 . The marking head  231  is used for producing a mark on the barcode paper M 3 ′. The solenoid valve  232  is connected with the marking head  231  for moving the marking head  231  upwardly and downwardly with respect to the barcode paper M 3 ′. The marking head  231  is for example a seal, a punching head, a trimming knife or any other marking tool. Corresponding to the marking head  231 , the mark is an unqualified symbol, an opening or a notch. In this embodiment, the marking head  231  is a punching head, and the mark is an opening. 
     Please refer to  FIG. 5 . The gear set  25  comprises a driving gear  251 , a first adjusting gear  252 , a ribbon driving gear  253 , a second adjusting gear  254 , a transfer paper driving gear  255 , a first transmission gear  256 , a third adjusting gear  257  and a second transmission gear  258 . The power-providing device  22  is connected with the driving gear  251  to rotate the driving gear  251  in the clockwise direction (in the viewpoint of  FIG. 5 ). In this embodiment, the power-providing device  22  is a motor. 
     The mechanism of receiving the motive power by the printing module  20  will be illustrated as follows. Since the first adjusting gear  252  is engaged with the driving gear  251 , the first adjusting gear  252  is synchronously rotated with the driving gear  251 . In addition, since the first adjusting gear  252  is engaged with the ribbon driving gear  253 , the ribbon driving gear  253  is rotated with the first adjusting gear  252 . In this embodiment, the first adjusting gear  252  is rotated in the anti-clockwise direction, and the ribbon driving gear  253  is rotated in the clockwise direction. Since the ribbon driving gear  253  is connected with the ribbon recovering terminal  2012 , the ribbon R is transported to the ribbon recovering terminal  2012  upon rotation of the ribbon recovering terminal  2012 . Similarly, since the second adjusting gear  254  is engaged with the driving gear  251 , the second adjusting gear  254  is synchronously rotated with the driving gear  251 . In addition, since the second adjusting gear  254  is engaged with the transfer paper driving gear  255 , the transfer paper driving gear  255  is rotated with the second adjusting gear  254 . In this embodiment, the second adjusting gear  254  is rotated in the anti-clockwise direction, and the transfer paper driving gear  255  is rotated in the clockwise direction. Since the transfer paper driving gear  255  is connected with the transfer paper recovering terminal  2022 , the releasing paper part M 1 ′ of the transfer paper M′ is transported to the transfer paper recovering terminal  2022  upon rotation of the transfer paper recovering terminal  2022 . 
     The mechanism of receiving the motive power by the identification module  21  will be illustrated as follows. The first transmission gear  256  is connected with the first transport roller assembly  213 , and the second transmission gear  258  is connected with the second transport roller assembly  214 . Since the first transmission gear  256  is engaged with the driving gear  251 , the first transmission gear  256  is synchronously rotated with the driving gear  251 . In addition, since the third adjusting gear  257  is engaged with the second transmission gear  258 , the second transmission gear  258  is rotated with the third adjusting gear  257 . In this embodiment, the third adjusting gear  257  is rotated in the clockwise direction, and the first transmission gear  256  and the second transmission gear  258  are rotated in the anti-clockwise direction. Consequently, as the first transmission gear  256  and the second transmission gear  258 , the barcode paper M 3 ′ will be transported. From  FIG. 5 , it is noted that the power-providing device  22  is connected with the printing module  20  and the identification module  21  through the gear set  25  for providing the motive power to the printing module  20  and the identification module  21 . 
     Hereinafter, the operations of the printing device  2  with the marking function will be illustrated with reference to  FIGS. 4 and 5 . During the operation of the printing device  2 , the printing module  20  and the identification module  21  are enabled, so that the transfer paper M′ and the ribbon R′ are transported through the region between the thermal print head  203  and the print roller  204 . If the passage of the transfer paper M′ and the first thickness T 1  of the transfer paper M′ are detected by the sensor  24 , it means that only the releasing paper part M 1 ′ of the transfer paper M′ (excluding the medium part M 2 ′) passes through the sensor  24 . Whereas, if the second thickness T 2  of the transfer paper M′ is detected by the sensor  24 , it means that the combination of the releasing paper part M 1 ′ and the medium part M 2 ′ passes through the sensor  24 . In this situation, the sensor  24  issues a driving signal to the printing module  20 . At the moment when the printing module  20  is enabled, the controlling unit  212  starts to count time. After the controlling unit  212  has counted time for a predetermined time period, the scanning element  211  is enabled by the controlling unit  212  to perform a scanning operation. 
     After the printing module  20  is enabled, the thermal print head  203  will heat the ribbon R′ to allow the coating of the ribbon R′ to be adsorbed on the medium part M 2 ′ of the transfer paper M′. In such way, a thermal transfer printing operation is performed to print the medium part M 2 ′ as a barcode paper M 3 ′. In addition, the print roller  204  may facilitate the thermal print head  203  to perform the thermal transfer printing operation and transport the transfer paper M′. Consequently, the releasing paper part M 1 ′ is transmitted to the transfer paper recovering terminal  2022 , and the barcode paper M 3 ′ is transmitted to the identification module  21 . After the barcode paper M 3 ′ is transmitted to the identification module  21  for the predetermined time period, the scanning element  211  is enabled to perform the scanning operation. Next, the barcode paper M 3 ′ is transported through the scanning element  211  by the first transport roller assembly  213 , so that the barcode paper M 3 ′ is scanned by the scanning element  211  to acquire the scanned barcode image. Then, the scanned barcode image is compared with the preset barcode image. If the controlling unit  212  judges that the scanned barcode image from the barcode paper M 3 ′ is identical to the preset barcode image, the marking element  23  is disabled and the barcode paper M 3 ′ is continuously transported by the second transport roller assembly  214  to be departed from the printing module  20 . Whereas, if the scanned barcode image is different from the preset barcode image, the solenoid valve  232  of the marking member  23  is enabled. Then, the marking head  231  connected with the solenoid valve  232  is moved downwardly to contact with the barcode paper M 3 ′ and punch an opening in the barcode paper M 3 ′, and the barcode paper M 3 ′ is transported by the second transport roller assembly  214  to be departed from the printing module  20 . In such way, the user may realize whether the barcode paper M 3 ′ is qualified or not according to the presence or absence of the opening in the barcode paper M 3 ′. 
     From the above description, the printing device of the present invention has a marking function. Since the identification module and the marking member are arranged at a downstream side of the printing module, the barcode paper is successively transported through the printing module, the identification module and the marking member. In this situation, if the barcode paper is deemed to be unqualified, the barcode paper dose not need to be returned back. On the other hand, the barcode paper is continuously moved forwardly and then the marking member produces the mark on the unqualified barcode paper. In other words, the printing device of the present invention does not need complex control and precise computation to process the unqualified barcode paper. Consequently, the printing device of the present invention does not use three power-providing devices to respectively drive the ribbon transport module, the transfer paper transport module and the print roller. Since a single power-providing device is used to simultaneously drive the ribbon transport module, the transfer paper transport module and the print roller, the printing device of the present invention is more cost-effective. 
     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.