Abstract:
A rotary machine including a substantially vertical rotatable drum having pellet-receiving receptacles in its peripheral sidewall. Gravity causes pellets to collect toward the drum&#39;s bottom. As the drum rotates, pellets received in the receptacles are carried upwardly from the bottom. A printing device positioned within the peripheral sidewall prints indicia on the inwardly exposed surfaces of the pellets. Optionally, the receptacles define apertures extending through the peripheral sidewall, and a printing device is positioned externally to the peripheral sidewall to print indicia on the outwardly exposed surfaces of the pellets. Drilling or inspection devices may be provided in addition to, or instead of, the printing devices. A support member may be provided adjacent the peripheral sidewall to prevent gravity from causing the pellets to exit the receptacles. Chutes may be provided to supply and remove pellets to and from the drum. An air stream may eject pellets from their receptacles.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   The present application claims the benefit of U.S. Provisional Patent Application No. 60/690,015, filed Jun. 13, 2005, the entire disclosure of which is hereby incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The present invention relates to printing machines for imprinting indicia on tablets, pills, candies, or other uniformly shaped products. 
   DISCUSSION OF THE RELATED ART 
   In the manufacture of many pharmaceutical products such as pills or lozenges, candies such as “M&amp;M&#39;s” and small mechanical parts, it is often desirable to imprint a trademark, indicia or other information or intelligence on each item. These products share a common characteristic in that they are all pellet-like, being small, often round or rounded, oval, bulbous, cylindrical or polygonal in shape. Examples of pellet-like items (“pellets”) are pills, lozenges, capsules, tablets, caplets and certain candies. 
   Imprinting indicia on a series of pellets is often accomplished by a machine that receives a large number of pellets in bulk, typically from a feed hopper or bin, orients the pellets, conveys the oriented pellets to a printing unit wherein the indicia are applied to each pellet, and discharges the pellets for subsequent packaging. 
   U.S. Pat. No. 2,859,689 to Ackley, the entire disclosure of which is hereby incorporated herein by reference, is a typical example of a pellet-marking machine which performs the steps outlined above. Pellets, seen in FIG. 2 of the &#39;689 patent, designated “P”, are loaded in bulk into the feed hopper 22 where they are received by a rotating drum or cylinder roll 23. The drum has a multiplicity of concavities or recesses 33 in its outwardly facing surface formed in accordance with the shape and size of the pellets being processed. The pellets P are received into the concavities 33 as the drum rotates clockwise beneath hopper 22, retained in the concavities by cylindrical retainer surface 50 as the drum rotates and released to an endless conveyor 24 located beneath the drum, the conveyor having a multiplicity of individual carrier bars 110. Carrier bars 110 have corresponding concavities matching the concavities 33 in drum 23, and conveyor 24 is synchronized with drum 23 so that the matching concavities on the drum and the conveyor line up as the drum rotates clockwise and the conveyor circulates counterclockwise. Pellets P drop from concavities 33 in drum 23 into the matching concavities in the endless conveyor 24 once the items are clear of retaining surface 50. The pellets P are then conveyed to a printing roller 27 which has ink laden images of the indicia or intelligence to be imprinted on the pellets peripherally arrayed on its peripheral surface. Printing roller 27 rotates clockwise in synchronization with endless conveyor 24 and contacts the pellets P as they pass beneath the printing roller 27, applying the ink laden image to each pellet. After passing beneath printing roller 27 the pellets P are discharged from conveyor 24 as the conveyor rounds its drive sprocket and the carrier bars 110 are momentarily vertically oriented. 
   U.S. Pat. No. 4,377,971 to Ackley, the entire disclosure of which is hereby incorporated herein by reference, discloses another exemplary pellet-printing machine including a two-drum rectifying and rotary printing system for printing indicia on pellets 3, as shown in FIG. 1. Pellets 3 are loaded in bulk into a feed hopper 1. A first drum 5 rotates adjacent to the hopper and picks up the pellets in concavities 9 positioned on the drum&#39;s outer surface. As the drum rotates, the pellets are captured within the concavities by a curved surface 23 located adjacent to drum 5. The pellets are transferred to a second drum 46 positioned beneath drum 5, the second drum 46 also having concavities 44 on its outer surface. Second drum 46 rotates synchronously with drum 5, the concavities on each drum aligning with one another to effect transfer of the pellets. Continued rotation of drum 46 moves the pellets past a printing station which comprises a rubber print roller 69 and an image roller 71. Indicia are transferred from the rubber print roller 69 to the pellets as they contact the rubber roller while traversing the printing station. During printing, the pellets are held within concavities 44 on the outer surface of the second drum by a wire guide 73 that is positioned between the printing station and the outer surface of the drum 48. The pellets are discharged into a chute 82 after they have completed traversal of the length of the wire guide 73. 
   U.S. Pat. No. 3,889,591 to Noguchi, the entire disclosure of which is hereby incorporated herein by reference, discloses yet another exemplary pellet printing machine including a two-drum printing system for printing indicia on pellets T, as shown in FIG. 1. Pellets T are loaded in bulk into a feed hopper 23. A first drum 17 rotates adjacent to the hopper and picks up the pellets in receptacles 17 a  positioned on the drum&#39;s outer surface. As the drum rotates, the pellets T are held within the receptacles 17 a  by vacuum as they travel past a first printing station 30, which includes a rotogravure cylinder positioned for printing on the exposed first surfaces of the pellets T. The pellets are then transferred to a second drum 18 positioned beneath the first drum 17, the second drum 18 also having receptacles 18 a  on its outer surface. Second drum  18  rotates synchronously with first drum 17, the receptacles on each drum aligning with one another to effect transfer of the pellets, with the assistance of vacuum and air sources. During this transfer to the second drum 18, the pellets T are re-oriented to expose their respective opposite second surfaces. Continued rotation of second drum 18 moves the pellets T past a second printing station 30′ which includes another rotogravure cylinder positioned for printing on the exposed second surfaces of the pellets T. The pellets are discharged into a chute 36 after they have completed traversal of the second printing station 30′. 
   The use of multiple drums for transporting the pellets, and the resulting need for synchronization of the drums, adds to the complexity and associated manufacturing and maintenance costs of such machines. 
   SUMMARY OF THE INVENTION 
   The present invention provides a single-drum machine for marking, drilling, and/or inspecting pellet-like objects, such as pharmaceutical tablets and capsules, as well as confections such as M&amp;Ms, e.g. to print brand names, logos or other indicia on such objects. 
   The machine includes a support structure, a drum rotatably carried on the support structure, a drive system operable to rotate the drum, and a printing device for printing desired indicia on the pellets. The drum has a peripheral sidewall defining an inner portion of the drum. The drum&#39;s sidewall has an inner surface that defines a plurality of receptacles. Each of the receptacles is dimensioned to receive a pellet. The receptacles may be configured to define an aperture that is open through the sidewall to allow for printing on the outwardly facing sides of the pellets, e.g., when two-sided printing is desired. The printing device is fixed relative to the support structure, and may be positioned internally to the drum for printing on inwardly facing surfaces of the pellets, or externally to the drum for printing on outwardly facing surfaces of the pellets. Optionally, the printing machine includes multiple printing (or drilling or inspecting) devices, one of which is positioned internally to the drum, another of which is positioned externally to the drum, so that the pellets may be imprinted (or drilled or inspected) on both their inwardly and outwardly facing surfaces. 
   Gravity causes pellets fed to an interior portion of the drum to collect toward its bottom. As the drum rotates, pellets received in the receptacles are carried upwardly from the bottom. In one embodiment, a first printing device positioned within the peripheral sidewall prints indicia on the inwardly exposed surfaces of the pellets, and a second printing device positioned externally to the peripheral sidewall prints indicia on the outwardly exposed surfaces of the pellets. A support member may be provided internally to the peripheral sidewall to prevent gravity from causing the pellets to exit the receptacles as the drum rotates. Chutes may be provided to supply pellets to an internal portion the drum, and to remove printed pellets from the drum. An air stream may be used to eject printed pellets from their receptacles and direct them to a discharge chute. 
   Accordingly, the printing machine described above allows for two-sided printing of pellets while requiring only a single drum for transporting the pellets. The need for multiple drums and synchronization of drums is thus eliminated. Additionally, the single-drum machine eliminates the need to re-orient the pellets relative to the drum between printing operations for printing on the first and second opposite surfaces of the pellets. Further, the printing machine described above uses the drum itself as a pellet hopper for feeding pellets, feeds pellets to receptacles in the drum from the interior portion of the drum, and is configured to carry pellets, and print upon pellets, while they are carried on an inner surface of the drum. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will now be described by way of example with reference to the following drawings in which: 
       FIG. 1  is a perspective view of a printing machine in accordance with an exemplary embodiment of the present invention; 
       FIG. 2  is a front view of the printing machine of  FIG. 1 ; 
       FIG. 3  is side view of the printing machine of  FIG. 1 ; 
       FIG. 4  is an enlarged partial perspective view of the hopper of the printing machine of  FIG. 1 ; 
       FIG. 5  is an enlarged partial perspective view of the outer surface of the drum of the printing machine of  FIG. 1 ; 
       FIG. 6  is an enlarged partial perspective view of the supply and discharge chutes of the printing machine of  FIG. 1 ; and 
       FIG. 7  is a front side view of an alternative embodiment of the printing machine of  FIG. 1 . 
   

   DETAILED DESCRIPTION 
   The present invention provides a machine for transporting and marking pellet-like objects, such as pharmaceutical tablets and capsules, as well as confections such as M&amp;Ms, with brand names, logos or other indicia. The machine allows for printing (or drilling or inspecting) on opposite surfaces (e.g., opposite sides) of pellets while requiring only a single drum for transporting the pellets, thus eliminating the need for synchronization of multiple drums. Further, the single-drum machine eliminates the need to re-orient the pellets relative to the drum between printing operations for printing on the first and second sides of the pellets. 
     FIGS. 1-6  show an exemplary printing machine for printing indicia on a plurality of pellets of similar shape and size, such as M&amp;M® brand candies. Referring now to  FIGS. 1-3 , the machine  10  includes a support structure  12  on which a drum  14  is carried. The drum  14  is mounted on the support structure  12  so as to be rotatable about an axis A that is substantially horizontal, as best shown in  FIG. 3 . Accordingly, the machine  10  includes a drive system  50  operable to rotate the drum  14  relative to the support structure  12 , i.e. about the axis A. By way of partial example, such a drive system  50  may include an electrically powered motor  52 , a gear train  54 , and a control panel  56 , as shown in  FIGS. 1-3 . Suitable conventional drive systems are well known in the art and are outside of the scope of the present invention, and thus are not discussed in further detail herein. A rotation speed of 7 RPM has been found suitable for printing. 
   The drum  14  has a peripheral sidewall  16  defining an inner portion  18  of the drum  14 . The sidewall  16  is preferably circular, i.e. circumferential, and has an inner surface  20 , which is proximate to the axis A. By way of example, the sidewall  16  may be between 24 and 48 inches in diameter. The inner surface  20  defines a plurality of receptacles  22 , as best shown in  FIGS. 1 and 4 . In one embodiment, the receptacles  22  are arranged in axial and circumferential rows. In a preferred embodiment, the receptacles  22  are arranged in axial rows that are not circumferential, but rather are nested, as shown in  FIGS. 1-6  and best shown in  FIG. 4 . Such a nested configuration may be useful to increase throughput by increasing the number of pellets carried per unit of circumference of the sidewall. Each of the receptacles  22  is dimensioned to receive a respective one of the pellets P, but to prevent passage of a pellet through the sidewall  16 , as best shown in  FIGS. 4 and 6 . 
   In one embodiment, each receptacle  22  is merely a concavity formed in the inner surface  20  of the peripheral sidewall  16  that is open to the inner portion  18  of the drum  14 , as best shown in  FIG. 4 . Accordingly, the receptacle is open on only one side of the peripheral sidewall  16 , namely along the inner surface  20  [not shown]. Such an embodiment is sufficient, for example, when it is desired to print on (or drill, or inspect) only one side of each pellet, namely, the inwardly facing side of each pellet, such printing being discussed in greater detail below. 
   In an alternative embodiment, as shown in  FIGS. 1-6 , each receptacle  22  defines an aperture  22   a  that is open through the peripheral sidewall  16 , as best shown in  FIGS. 1 and 4 . Accordingly, the receptacle is open on both sides of the peripheral sidewall  16 , namely along both the inner surface  20  and the outer surface  24  of the sidewall  16 , as best shown in  FIGS. 1 and 6 . Such an embodiment is desirable, for example, when it is desired to print on (or drill, or inspect) both of two opposite surface of each pellet, namely, both the inwardly facing surface and the outwardly facing surface of each pellet, such printing being discussed in greater detail below. 
   In the alternative embodiment discussed above, each receptacle  20  may be dimensioned and/or contoured so that at least a portion of each pellet projects through a respective aperture  22   a  and thus extends beyond the outer surface  24  of the peripheral sidewall  16 . Such a configuration may be particularly desirable when physical contact with the pellet is required during the printing process, as when a rotogravure type printing device is used for printing. 
   Alternatively, each receptacle may be dimensioned and/or contoured so that no portion of each pellet projects through a respective aperture  22   a , and thus no portion of each pellet extends beyond the outer surface  24  of the peripheral sidewall  16 . Such a configuration may be suitable when physical contact with the pellet is not required during the printing process, as when a laser printer type printing device is used for printing. 
   In yet another embodiment, each receptacle is not a concavity but rather simply an opening through which the pellet may pass through the sidewall. In such an embodiment, additional structures adjacent the sidewall  16 , such as member  68  or structure  70  discussed below, help retain each pellet in a receptacle. 
   In all of the receptacle configurations discussed above, portions of the pellets are accessible for printing via a respective aperture of each of said plurality of receptacles. Preferably, the sidewall is chamfered around each receptacle to facilitate seating of a pellet with the receptacle, and to reduce the possible of damage to pellets. 
   Optionally, the printing machine  10  includes a bracing wall  28  cooperating with the drum  14  to provide a pellet hopper  30 . In one embodiment, the bracing wall is joined to the peripheral sidewall  16  of the drum  14 , and extends radially inwardly of the drum, as shown in  FIG. 7 . Accordingly, a pellet hopper  30  is formed toward the bottom of the drum, the pellet hopper&#39;s walls being defined along the bottom by the sidewall  16 , and along the sides by an end wall  32 , which may be a rotating portion of the drum  14  or a stationary portion of the support structure, and the bracing wall  28 . 
   In an alternative embodiment, the bracing wall  28  is fixed in position relative to the support structure  12  in adjacent relationship to the peripheral sidewall  16  of the drum, as best shown in  FIGS. 1 and 4 . Accordingly, the pellet hopper&#39;s  30  walls are defined along the bottom by the sidewall  16 , and along the sides by the end wall  32  and the bracing wall  28 , as best shown in  FIGS. 1 and 4 . 
   An exemplary embodiment of the printing machine  10  also includes first and second printing devices. Suitable conventional printing devices are well known in the art and thus are not discussed in detail herein. By way of example, a conventional rotogravure, ink jet or laser printer device may be used. Alternatively, laser drilling equipment and/or a camera and/or other inspection equipment may be used as part of, in conjunction with, or instead of the printing devices described above. Such devices may be positioned relative to the sidewall  16  in a manner similar to the printing devices discussed above. Accordingly, such devices are interchangeable in a manner relevant to the operation of the device. For illustrative purposes, the machine is described below with reference to a printing device. 
   One or more printing devices may be used, and the devices may provide for printing on one side, or on both opposite sides, of each pellet. Each printing device is preferably fixed relative to the support structure  12 , e.g. on the support structure  12 , in position to print indicia on each of the pellets while the pellets are positioned within the receptacles  22 . Thus, printing on the pellets occurs as the drum  14  rotates relative to the support structure  12 . The printed portion may be either the inwardly facing surfaces of the pellets or the outwardly facing surfaces of the pellets. The printing device may thus be mounted internally to, or externally to, the inner portion of the drum, as desired. 
   In a preferred embodiment, the printing machine  10  includes at least two printing (or drilling or inspecting) devices, one of which is positioned to print (or drill or inspect) indicia on a respective first portion of each of the pellets, and another which is positioned to printing indicia on a respective second portion of each of the pellets, each second portion being opposite a respective first portion. Exemplary printing devices are shown diagrammatically in block form at  42  and  44  in  FIGS. 4 and 5 . As discussed above, the block form  42  may additionally or alternatively represent a laser drilling device or a camera or other inspection devices, as will be appreciated by those skilled in the art. The printing devices are omitted from the remaining Figures for illustrative clarity. 
   The printing machine  10  may further include a first chute  60  fixed relative to, e.g. mounted on, the support structure  12  in a position to direct a supply of pellets to the inner portion  18  of the drum  14  and/or a second chute  64  fixed relative to, e.g. mounted on, the support structure  12  in a position to direct pellets imprinted with indicia away from the inner portion  18  of the drum  14 , as best shown in  FIG. 6 . 
   In an embodiment in which a printing device is located externally to the inner portion (see printing device  44 ,  FIG. 5 ) of the drum  14 , or in which the second chute  64  is located high enough relative to the bottom of the drum  14  that gravity tends to cause the pellets to exit their respective receptacles (see  FIG. 6 ), the printing machine  10  may also include a support member  58  fixed in position relative to, e.g. mounted on, the support structure  12 , as shown in  FIGS. 1 ,  2 ,  4  and  5 . The support member  68  is positioned within the inner portion  18  of the peripheral sidewall  16 /drum  14  in a position to prevent gravity from causing said pellets to exit respective ones of said plurality of receptacles, as best shown in  FIG. 1 . 
   Optionally, the printing machine  10  includes a nozzle  80  connected to an air source and supported externally to the internal portion of the peripheral sidewall  16  in a position to direct a flow of air toward the internal portion  18  of the peripheral sidewall  16 , e.g. radially inwardly, as shown in  FIG. 5 . In this manner, the nozzle  80  directs air from the outer surface  24  toward the inner surface  20  of the peripheral sidewall  16  and is thus capable of dislodging a pellet P from a respective one of the plurality of receptacles  22  and direct it into the second chute  58 . Alternatively, the receptacles may be configured to allow the pellets to pass through the sidewall  16 , and the nozzle  80  may be positioned internally to the internal portion of the peripheral sidewall  16  in a position to direct a flow of air toward the outer portion of the peripheral sidewall  16 , e.g. radially outwardly, as best shown in  FIG. 7 . 
   Optionally, the printing machine  10  further includes a vacuum chest  70  or other structure configured to draw a vacuum through the receptacles of the portion of the peripheral sidewall  16  that is presently positioned within the hopper  30 , as best shown in  FIG. 1 . This facilitates the seating of individual pellets  22  within the receptacles  20  of the peripheral sidewall  16 , and may be particularly useful to expedite such seating when the drum  14  is rotating at a relatively high rate of rotation. 
   In use, the exemplary printing machine of  FIGS. 1-6  is operable to print on both sides of pellets P. Pellets are fed in bulk via supply chute  60  to the inner portion  18  of the drum  14  of the printing machine  10 . Gravity causes the pellets P to tend to collect toward the bottom of the drum  14 , namely in hopper  30  formed toward the bottom of the drum  14  by the end wall of the drum  14 , the peripheral sidewall  16  of the drum  14  and the bracing wall  28 , as best shown in  FIG. 4 . 
   As the peripheral sidewall  16  rotates through the hopper  30 , in the counterclockwise direction shown in  FIG. 2 , pellets P are received within the receptacles  20 , as best shown in  FIG. 4 . This may be facilitated by a vacuum flow being drawing through the receptacles  22 . As the drum  14  continues to rotate, individual pellets P seated within the receptacles  22  travel up and away from the hopper  30 , as best shown in  FIGS. 4 and 5 . 
   In the exemplary embodiment of  FIGS. 1-6 , a first printing  42  device is positioned interior to the inner portion  18  of the drum  16 , as shown in  FIG. 4 . Accordingly, the pellets P positioned within the receptacles  22  travel past the first printing device  42  and are printed on their respective first portions, namely, their inwardly facing sides, with appropriate indicia. 
   As the drum  14  continues to rotate, the pellets P become trapped within the receptacles  22  as they travel adjacent the support member  68  positioned within the inner portion of the drum  14 , as shown in  FIGS. 4 and 5 . The support member  68  is positioned in close proximity to the inner surface  20  of the peripheral sidewall  16  and thus prevents the pellets P from exiting the individual receptacles under gravitational pull, as best shown in  FIGS. 2 ,  4  and  5 . 
   A second printing device  44  is positioned externally to the inner portion  18  of the drum  14 . Accordingly, the pellets P positioned within the receptacles next travel past the second printing device  44  and are printed on their respective second portions, namely, their outwardly facing sides, with appropriate indicia, as best shown in  FIGS. 2 ,  4  and  5 . It is noted that the printing on these outwardly facing sides occurs by printing through the apertures  20   a  of the receptacles, or by printing on a portion of the pellets P that projects through such apertures  20   a.    
   Accordingly, because the printing devices  42 ,  44  are positioned on opposite sides of the peripheral sidewall  16  of the drum  14 , they can print indicia on both opposite surfaces of the pellets P without the need to pass the pellets P between multiple drums, or to reorient the pellets after they are seated in a first drum. 
   After printing, as the drum  14  continues to rotate, the pellets P clear the support member  68  and arrive at an entry point for the discharge chute  64 , as best shown in  FIGS. 2 ,  5  and  6 . The pellets P then exit their respective receptacles  22 , either by gravity or by a flow of air directed toward the pellets P from a nozzle  80  external to the drum  14 , and enter the discharge chute  64 , which directs them away from the inner portion  18  of the drum  14 , e.g. into another hopper, etc. for packaging, etc. 
   Preferably, the drum is caused to rotate continuously at a substantially constant rate of rotation, the vacuum and air streams flow continuously, and pellets are fed to the drum continuously, at a rate that is controlled to prevent overflowing of the hopper or overburdening of the drum/drive system. 
   Accordingly, the printing machine described above allows for two-sided printing of pellets while employing only a single drum for transporting the pellets. The need for multiple drums and synchronization of drums is thus eliminated. Further, the printing machine described above uses the drum itself as a pellet hopper for feeding pellets, feeds pellets to receptacles in the drum from the interior portion of the drum, and is configured to carry pellets, and imprint pellets, while they are carried on an inner surface of the drum. 
     FIG. 7  is a front side view of an alternative embodiment of the printing machine of  FIG. 1 . The printing machine of  FIG. 7  is similar to that of  FIGS. 1-6  in that it includes a rotatable drum  14  having a sidewall  16 , etc. However, in this embodiment the drum  14  includes a first portion of an end wall (obscured in  FIG. 7  by bracing wall  28 ) that is fixed to and rotates with the sidewall  16 , and a second portion  32   b  of an end wall that is fixed to the support structure  12  and does not rotate with the sidewall  16 . A conventional motorized drive system may be used for driving a drum in this manner. By way of example, a toothed ring supported by bearings and driven by a drive gear may be used, such as a HEPCO ring system, such as model #R76-799-R360-P, manufactured and/or sold by Hepco Slide Systems Ltd. of Devon, England, is suitable for this purpose. The second portion  32   b  of the end wall therefore provides a convenient location for supporting printing and other devices. For illustrative purposes, two rotogravure printing devices  42 ,  44  are shown in  FIG. 7 . Alternatively, other conventional printing, inspecting or drilling equipment may be similarly positioned and used instead of printing devices  42 ,  44 . The supply chute  60  may also be positioned through the second portion  32   b , and may be fed by a hopper behind the drum. In this embodiment, the receptacles are configured to allow the pellets to pass through the sidewall. Thus, the exhaust chute  64  is positioned externally to the sidewall, and the air jet nozzle  80  is positioned within the sidewall  16  for blowing pellets outwardly through the sidewall  16  and into the exhaust chute  64 . 
   By way of example of alternative embodiments within the scope of the present invention, the drum may be configured with receptacles configured to receiving pellet-like objects having substantially round cross-sections, such as soft-gels, capsules or caplets, and conventional spin printing device equipment may be used to, for example, print on both opposite sides of the pellet from a single side of the drum by causing the pellet to rotate in the receptacle during the spin printing process. 
   As described above, a vacuum may be applied at a location generally opposing a printing or other device to uniformly position a pellet relative to the receptacle. 
   While there have been described herein the principles of the invention, it is to be understood by those skilled in the art that this description is made only by way of example and not as a limitation to the scope of the invention. Accordingly, it is intended by the appended claims, to cover all modifications of the invention which fall within the true spirit and scope of the invention.