Patent Publication Number: US-7217047-B2

Title: Thermal transfer printer

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This application claims the benefit of priority to Japanese Patent Application No. 2004-165534, filed on Jun. 3, 2004, herein incorporated by reference. 
   The present invention relates to a thermal transfer printer, more specifically, to a thermal transfer printer capable of reducing cost by reducing the number of the components of the ribbon cassette. 
   2. Description of the Related Art 
   A conventional thermal transfer printer  31  will be described with reference to a drawing. 
   As shown in  FIG. 3 , the thermal transfer printer  31  includes a printer main body  31   a , and a cassette mounting section  31   b  capable of mounting a ribbon cassette  39  to be described later in the printer main body  31   a.    
   A rotatable platen roller  32  is arranged in the printer main body  31   a , and a thermal head  33  is arranged on the platen roller  32 . 
   A recording paper  34  is fed between the thermal head  33  and the platen roller  32  so as to be carried in the direction of an arrow A. 
   The thermal head  33  is supported by a head mounting table  35  which is mounted on a head lever  36 . The head lever  36  is turned about a supporting shaft  37  as a fulcrum, so that the thermal head  33  can be brought into contact with and separated from the platen roller  32  (head up/down). 
   When a ribbon cassette  39  to be described later is mounted on the cassette mounting section  31   b  in a state in which the thermal head  33  is separated from the platen roller  32  (head up), an ink ribbon  38  is positioned between the platen roller  32  and the thermal head  33 . 
   The ink ribbon  38  is formed to have a slightly wider width than the recording paper  34  and both ends of the ink ribbon  38  are wound around a supply reel  39   a  and a take-up reel  39   b , respectively. The supply reel  39   a  and the take-up reel  39   b  are rotatably supported in ribbon housing sections  39   c  facing each other so as to be housed in the ribbon cassette  39 . 
   When the ribbon cassette  39  is mounted on the cassette mounting section  31   b , the take-up reel  39   b  is engaged with a take-up bobbin (not shown) of the printer main body section  31   a  so as to be rotated by the rotation of the take-up bobbin. 
   When the take-up reel  39   b  is rotated in the counterclockwise direction by rotating the take-up bobbin in the counterclockwise direction, the ink ribbon  38  wound around the supply reel  39   a  can be wound around the take-up reel  39   b.    
   Further, the ribbon cassette  39  is provided with a relief groove  39   d  for relieving a pressing roller  41  to be described later, and a take-up port  39   e  is provided in the lower portion of the relief groove  39   d . In addition, a guide roller  39   f  made of metallic rod is rotatably supported on a side plate adjacent to the take-up port  39   e.    
   The ink ribbon  38  to be wound around the take-up reel  39   b  is detached at a predetermined detachment angle from a ribbon detaching member  42  provided downstream in the ribbon-feeding direction of the thermal head  33 . Then, the ink ribbon  38  is bent substantially orthogonally by the guide roller  39   f  so as to be wound around the take-up reel  39   b.    
   In addition, a paper feeding roller  40  and a pressing roller  41  which is pressed against the paper feeding roller  40  are arranged on the left side of the platen roller  32  in  FIG. 3 . The recording paper  34  is interposed between the paper feeding roller  40  and the pressing roller  41  so that the recording paper  34  can be carried in the direction of the arrow A by the rotation of the paper feeding roller  40  in the counterclockwise direction. 
   When the ribbon cassette  39  is mounted on the cassette mounting section  31   b , the pressing roller  41  is positioned in the relief groove  39   d.    
   The above-mentioned conventional thermal transfer printer is described in Japanese Unexamined Patent Application Publication Nos. 2002-144616 and 2002-120446. 
   However, since the above-mentioned conventional thermal transfer printer  31  uses the high-cost guide roller  31  made of metal in the ribbon cassette  39 , cost is increased. 
   In addition, when the ink ribbon  38  of ink is used up, the ribbon cassette  39  is discarded. In this case, since the guide roller  39   f  made of metal is also simultaneously discarded, resources are wasted. 
   SUMMARY OF THE INVENTION 
   The present invention has been to solved the above-mentioned problems, and it is an object of the present invention to provide a thermal transfer printer which includes a ribbon guide section capable of guiding an ink ribbon provided in a main body case so that the ribbon guide section is not mounted on the ribbon cassette. Therefore, it is possible to reduce resource waste at low running cost. 
   According to a first aspect of the present invention to solve the above-mentioned problems, a thermal transfer printer includes a ribbon cassette having a first ribbon housing section for housing a supply reel around which an unused ink ribbon is wound and a second ribbon housing section for housing a take-up reel around which a used ink ribbon is wound, a cassette mounting section on which the ribbon cassette can be mounted, a thermal head, a platen roller which can be brought into contact with and separated from the thermal head, and a paper feeding mechanism capable of carrying a recording paper which is fed between the platen roller and the thermal head. The ribbon cassette is provided with a head insertion section in which the thermal head is positioned and a relief groove having a predetermined depth in which the paper feeding mechanism can be positioned between the first ribbon housing section and the second ribbon housing section, and the ink ribbon to be wound around the take-up reel is exposed to the relief groove. A ribbon guide section is arranged in the cassette mounting section so that the ink ribbon exposed to the relief groove of the mounted ribbon cassette can be bent toward the lower portion of the relief groove to be wound around the take-up reel. 
   Further, according to a second aspect of the invention to solve the above-mentioned problems, in the thermal transfer printer, the ribbon cassette includes a partitioning wall for partitioning the head insertion section and the relief groove, and when the ink ribbon cassette is mounted on the cassette mounting section, the ink ribbon can be drawn out from the supply reel through an end of the partitioning wall and the ribbon guide member to be wound around the take-up reel. 
   Furthermore, according to a third aspect of the invention to solve the above-mentioned problems, the ribbon guide section is composed of a rotatable guide roller. 
   The ink ribbon to be wound around the take-up reel is exposed to the relief groove of the ribbon cassette, and the cassette mounting section is provided with the ribbon guide portion which can bend the ink ribbon exposed to the relief groove of the mounted ribbon cassette toward the lower portion of the relief groove in order to be wound around the take-up reel. Therefore, the ribbon guide section may be not mounted on the ribbon cassette and a thermal transfer printer with low running cost can be provided because the cost of ribbon cassette can be reduced. In addition, resources can be prevented from being wasted. 
   In addition, the ribbon cassette is provided with the partitioning wall for partitioning the head insertion section and the relief groove, and is mounted on the cassette mounting section. Since the ink ribbon is drawn out from the supply reel through an end of the partitioning wall and the ribbon guide member so as to be wound around the take-up reel, it is possible to prevent the paper feeding mechanism positioned in the relief groove from being brought into contact with the ink ribbon. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic view illustrating a thermal transfer printer according to the present invention; 
       FIG. 2  is a cross-sectional view showing the main parts of a ribbon cassette according to the invention; and 
       FIG. 3  is a schematic view illustrating the main parts of a printer according to the related art. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Hereinafter, preferred embodiment of a thermal transfer printer  1  according to the present invention will be described with reference to the drawings. 
     FIG. 1  is a schematic view illustrating a thermal transfer printer according to the present invention and  FIG. 2  is a cross-sectional view showing the main parts of a ribbon cassette according to the invention. 
   As shown in  FIG. 1 , the thermal transfer printer  1  according to the invention is provided with a cylindrical platen roller  3  having a predetermined length in a main body case  2 . Both ends of a rotating shaft  3   a  of the platen roller  3  are rotatably supported by side walls  2   a  of the main body case  2 . 
   In addition, a thermal head  4  extending parallel to the longitudinal direction of the platen roller  3  is arranged on the upper side of the platen roller  3  and is mounted on a trapezoidal head mounting table  5 . The head mounting table  5  is mounted on the head lever  6  having an arm shape and the head lever  6  can swing about a swing point  6   a  as a fulcrum in the direction of arrows B and C which is the up and down direction in the drawing. 
   The thermal head  4  can move up and down with respect to the platen roller  3  by swing the head lever  6  in the direction of the arrows B and C. Further, a recording paper  7  is fed between the platen roller  3  and the thermal head  4 . 
   The thermal head  4  has a plurality of heat generating elements (not shown) provided in the portion facing the platen roller  3 . 
   Furthermore, a paper feeding mechanism  8  is arranged in the downstream side of the platen roller  3  in the feeding direction of the recording paper  7  which is indicated by an arrow D, and the paper feeding mechanism  8  is composed of a paper feeding roller  9  which can be driven to rotate and a pressing roller  10  which is pressed against the paper feeding roller  9 . 
   In a state in which the recording paper is interposed to be pressed between the paper feeding roller  9  and the pressing roller  10 , the thermal head  4  is moved down so as to perform printing and the recording paper  7  is carried downstream (the left direction in the drawing) by the rotation of the paper feeding roller  9  in the counterclockwise direction, i.e. the direction of an arrow E. 
   An ink ribbon  11  shown with a two-dot chain line is fed on the upper side of the recording paper  7  fed between the platen roller  3  and the thermal head  4 . The ink ribbon  11  is formed to have slightly wider width than that of the recording paper  7 . A desired color of ink is coated on the lower surface of the in ribbon  11  in the drawing (the surface facing the recording paper  7 ), so that the ink can be transferred onto the recording paper  7  by the thermal head  4 . The ink ribbon  11  is housed in a cassette  14  with both ends thereof wound around the supply reel  12  and the take-up reel  13 , respectively. 
   As shown in  FIG. 2 , the ribbon cassette  14  includes a first ribbon housing section  14   a  for housing the supply reel  12  around which unused ink ribbon  11  is wound, and a second ribbon housing section  14   b  for housing the take-up reel  13  around which used ink ribbon  11  is wound. 
   The first and second ribbon housing sections  14   a  and  14   b  are connected by connection walls  14   c  which are formed to face each other. A draw-out port  14   d  through which the ink ribbon  11  wound around the supply reel  12  can be drawn out is provided in the lower portion of the first ribbon housing section  14   a.    
   The ribbon cassette  14  has a head insertion section  15  between the connection walls  14   c  facing each other, in which the thermal head  4  can be positioned and move up and down between the first ribbon housing section  14   a  and the second ribbon housing section  14   b.    
   Further, a relief groove  16  having a predetermined depth is provided between the head insertion section  15  and the second ribbon housing section  14   b , so that the paper feeding mechanism  8  can be positioned therein. 
   Furthermore, a partitioning wall  17  is formed between the head insertion section  15  and the relief groove  16  in the ribbon cassette  14 , and a draw-in port  14   e  through which the ink ribbon  11  drawn out from the draw-out port  14  can be drawn in is provided in the lower side of the relief groove  16 . 
   Moreover, as shown in  FIG. 2 , the ink ribbon which is drawn out from the draw-out port  14   d  and is drawn through the lower portion of the partitioning wall  17  is exposed to the relief groove  16 . The ink ribbon  11  exposed to the relief groove  16  is wound around the take-up reel  13 . 
   In addition, the main body  2  provided with a cassette mounting section  18  in which the ribbon cassette  14  can be mounted. A ribbon guide section  19  composed of a metallic guide roller is rotatably arranged on the side wall  2   a  of the cassette mounting section  18 . 
   When the ribbon cassette  14  is mounted on the cassette mounting section  18 , the ribbon guide section  19  is positioned to the lower portion of the relief groove  16 , so that the ink ribbon  11  exposed to the relief groove  16  is bent toward the lower portion of the relief groove  16 , as shown in  FIG. 1 . 
   Therefore, when the ribbon cassette  14  is mounted on the cassette mounting section  18 , it is possible to prevent the ink ribbon  11  from bringing into contact with the pressing roller  10  of the paper feeding mechanism  8  and to smoothly wind the ink ribbon  11  around the take-up reel  13 . 
   Further, the supply reel  12  is engaged with a supply-side bobbin (not shown) arranged inside the main body case  2 , and the take-up reel  13  is engaged with a take-up side bobbin (not shown). 
   Hereinafter, a printing operation of the thermal transfer printer  1  of the invention will be described. First, if the head lever  6  is swung in the upward direction of the arrow C at a wide angle so that the ribbon cassette  14  is placed on the cassette mounting section  18  of the main body case  2 , the ink ribbon  11  is positioned on the platen roller  3 . Simultaneously, the ink ribbon  11  exposed to the relief groove  16  is bent toward the lower portion of the relief groove  16  by the ribbon guide section  19  which is a guide roller made of metal. 
   After that, the recording paper  7  is fed in the feeding direction of the arrow D so as to be interposed to be pressed between the paper feeding roller  9  and the pressing roller  10 . Further, the recording paper  7  is carried in the same direction so that the recording paper  7  is headed. Then, the printing starting position is aligned with the heat generating elements of the thermal head  4 . Next, the first color (for example, cyan) of the ink ribbon  11  is headed. 
   The thermal head  4  is moved down so that the ink ribbon  11  is pressed against the recording paper  7 , and a plurality of heat generating elements are selectively heated based on printing information. Next, the paper feeding roller  9  is rotated in the direction of the arrow E so that the recording paper  7  is carried downstream (the direction of an arrow F). Then, the first color ink of the ink ribbon  11  is thermal-transferred onto the recording paper  7 . 
   When printing of the first color is completed, the recording paper  7  is carried again in the direction of the arrow D to be aligned with the printing starting position and the second color (for example, magenta) of the ink ribbon  11  is headed. In addition, the second color of printing is performed in the same way as the printing of the first color. When such operations are repeatedly performed and desired printing is completed, the recording paper  7  is carried in the direction of the arrow F to be discharged outside from the main body case  2 . 
   The used ink ribbon  11  of which ink has been transferred onto the recording paper is wound around the take-up reel  13  via the ribbon guide section  19 . 
   When unused ink ribbon  11  wound around the supply reel  12  runs out, the used ribbon cassette  14  is removed from the cassette mounting section  18  to be replaced with an unused ribbon cassette  14 . 
   As described so far, the ribbon cassette  14  does not include the guide roller  39   f  made of metal unlike the conventional ribbon cassette  31 , which results in cost reduction. For this reason, the running cost of the thermal transfer printer  1  according to the invention, in which the low-cost ribbon cassette  14  is used, can be reduced. 
   In addition, the ribbon cassette  14  does not include a guide roller made of metal unlike the conventional ribbon cassette. Therefore, even though the ribbon cassette  14  is discarded after used, a guide roller is not discarded, so that waste of resource can be prevented.