Machine and ribbon spool for thermal transfer printing

Abstract

The machine (M) comprises at least one rotating spindle ( 1, 2; 1′, 2 ′), and at least one ribbon spool ( 30 ) mounted on the said spindle ( 1, 2; 1′, 2 ′) and having an axial passage ( 31 ) in which a transversely projecting locating formation ( 33 a ) is defined, and at least one transversely re-entrant connecting formation ( 35, 36 ). The or each spindle ( 1, 2; 1′, 2 ′) comprises an axial portion ( 15 ) on which a ribbon spool ( 30 ) is designed to be mounted, and which has a stop shoulder ( 25 ) against which the locating formation ( 33 a ) of the ribbon spool ( 30 ), and at least one transversely projecting element ( 18 a, 19 a ) able to engage in the connecting formation ( 35, 36 ) of the ribbon spool ( 30 ), are designed to abut in such a way that the spindle and the spool ( 30 ) rotate together.

1 . Thermal transfer printing machine (M) comprising 
 at least one rotating spindle ( 1 ,  2 ;  1 ′,  2 ′), and    at least one ribbon spool ( 30 ) mounted on the said spindle ( 1 ,  2 ;  1 ′,  2 ′) and having an axial passage ( 31 ) in which a transversely projecting locating formation ( 33   a ) is de-fined, and at least one transversely re-entrant connecting formation ( 35 ,  36 );    the spindle ( 1 ,  2 ;  1 ′,  2 ′) comprising    an axial portion ( 15 ) on which a ribbon spool ( 30 ) is designed to be mounted; the said axial portion ( 15 ) of the spindle having a stop shoulder ( 25 ) against which the locating formation ( 33   a ) of the ribbon spool ( 30 ) is designed to abut; and    at least one transversely projecting element ( 18   a ,  19   a ) able to engage in the connecting formation ( 35 ,  36 ) of the ribbon spool ( 30 ) in such a way that the spindle and the spool ( 30 ) rotate together;    the arrangement of the locating ( 33   a ) and connecting ( 35 ,  36 ) formations of the spool ( 30 ), and of the stop shoulder ( 25 ) and of the projecting element ( 18   a ,  19   a ) of the spindle being such that the ribbon spool ( 30 ) is connectable to the spindle simply by inserting the spindle through a pre-determined end ( 31   a ) of the axial passage ( 31 ) of the ribbon spool ( 30 ).    
   
   
       2 . Machine according to  claim 1 , in which the spindle ( 1 ,  2 ;  1 ′,  2 ′) is provided with tightening means ( 26 ,  27 ) capable of causing a radial movement of the abovementioned transversely projecting element ( 18   a ,  19   a ) towards the corresponding connecting formation ( 35 ,  36 ) on the ribbon spool ( 30 ) mounted on the spindle; the said tightening means comprising an actuating member ( 27 ) projecting beyond the ribbon spool ( 30 ) connected to the spindle.  
   
   
       3 . Machine according to  claim 2 , in which the spindle ( 1 ,  2 ;  1 ′,  2 ′) has a first and a second axial portions ( 15 ,  24 ) having a larger cross section and a smaller cross section, respectively, between which the abovementioned stop shoulder ( 25 ) is defined; at least one longitudinal slot ( 16 ,  17 ) being produced in the first axial portion ( 15 ) to take a radially movable key member ( 18 ,  19 ), one end ( 18   a ,  19   a ) of which extends along the said second axial portion ( 24 ) of the spindle and has a shaped profile, in particular an inclined plane ( 18   b ,  19   b ); 
 and in which the said second axial portion ( 24 ) of the spindle has a thread ( 26 ) on which a tapped part ( 27 ) is screwed, a first end ( 27   a ) of which projects out of the rib-bon spool ( 30 ) connected to the spindle, and the second end ( 27   b ) of which is able to interact with the said shaped pro-file ( 18   b ,  19   b ) of the key member ( 18 ,  19 ) in such a way as to bring about a movement of this key member ( 18 ,  19 ) towards the corresponding connecting formation ( 35 ,  36 ) on the ribbon spool ( 30 ).    
   
   
       4 . Machine according to  claim 3 , in which the said first axial portion ( 15 ) of the spindle has at least one peripheral groove ( 20 ,  21 ) containing an elastic sealing ring ( 22 ,  23 ) capable of keeping the said key member or members ( 18 ,  19 ) in the corresponding slot or seat ( 16 ,  17 ).  
   
   
       5 . Ribbon spool ( 30 ) for connection to a spindle ( 1 ,  2 ;  1 ′,  2 ′) of a thermal transfer printing machine (M), comprising 
 an essentially cylindrical tubular supporting element ( 32 ,  33 ), through which an internal axial passage ( 31 ) runs to accommodate the spindle; a variation of cross section being produced in an axially intermediate portion of the said passage ( 31 ) to define a transverse locating formation ( 33   a ), against which a reference and stop shoulder ( 25 ) on the spindle is designed to abut;    at least one connecting formation ( 35 ,  36 ) being produced in an axial portion ( 31   b ) of the said passage ( 31 ) and able to connect prismatically with a portion ( 18   a ,  19   a ) of the spindle, in such a way that they rotate together;    the connecting formation ( 35 ,  36 ) and the locating formation ( 33   a ) being produced in such a way that the said sup-porting element ( 32 ,  33 ) is connectable to the spindle purely by inserting the spindle through a predetermined end ( 31   a ) of the said axial passage ( 31 ).    
   
   
       6 . Ribbon spool according to  claim 5 , characterized in that it is a monolithic element, that is it is made in one piece.  
   
   
       7 . Ribbon spool according to  claim 5 , in which the said supporting element ( 32 ,  33 ) comprises 
 a cylindrical tubular core ( 32 ), on the periphery of which a ribbon (N; R) is to be wound, and    an insert ( 33 ) of essentially cylindrical tubular shape, which is shorter than the core ( 32 ) and is fixed inside the said core ( 32 ) in such a way that one of its ends defines the abovementioned locating formation ( 33   a ); 
 the said connecting formation or formations ( 35 ,  36 ) being formed in the inside surface ( 31   b ) of the insert ( 33 ).  
   
   
   
       8 . Ribbon spool according to  claim 7 , in which the said cylindrical tubular core ( 32 ) is made of board or the like, and the insert ( 33 ) is of a comparatively more rigid material, in particular a plastic material, and is driven with interference into the said core ( 32 ).  
   
   
       9 . Ribbon spool according to  claim 8 , in which the insert ( 33 ) has at least a plurality of peripheral projections ( 34 ), such as ribs or fluting, for digging into the core ( 32 ).  
   
   
       10 . Ribbon spool according to claims  7 , particularly for a printing machine (M) having at least two rotating spindles ( 1 ,  2 ;  1 ′,  2 ′) designed to take corresponding spools ( 30 ) of identical shape for corresponding ribbons (N, R) of equal width (L) and which in operation are unwound or wound in opposite directions; the said insert ( 33 ) being positioned axially in the core ( 32 ) in such a way that the end of the insert ( 33 ) which defines the abovementioned locating formation ( 33   a ) is at the central axial section of the core ( 32 ).  
   
   
       11 . Ribbon spool according to  claim 10 , in which the insert ( 33 ) has a length (I) equal to half the length (L) of the core ( 32 ).  
   
   
       12 . Ribbon spool according to  claim 10 , characterized in that it has a visible feature, such as color, which it shares with the spindle to which it must be connected in operation; the said feature being different for the two spindles and for the corresponding ribbon spools ( 30 ).  
   
   
       13 . Ribbon spool according to  claim 5 , in which the said connecting formation or formations is or are a slot ( 35 ,  36 ) formed in the inside surface of a smaller-diameter axial portion ( 31   b ) of the abovementioned passage ( 31 ).  
   
   
       14 . Ribbon spool according to  claim 13 , in which there are formed in the smaller-diameter axial portion ( 31   b ) of the abovementioned passage ( 31 ) two preferably diametrically opposite slots ( 35 ,  36 ) designed to be engaged by respective radial projections ( 18   a ,  19   a ) of the spindle.  
   
   
       15 . Reel ( 3 ,  4 ) of ribbon prewound for use in a thermal transfer printing machine (M), characterized in that it comprises a ribbon spool ( 30 ) according to  claim 5.