Patent Publication Number: US-4547250-A

Title: Apparatus for affixing labels to moving web

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an apparatus for affixing labels to a moving web and, more particularly, to an apparatus for affixing labels to a moving web in which sudden variation in tension of a label tape caused when a label separated from its base strip is affixed to a traveling web can be relieved and absorbed by an accompanying movement of the label tape in the direction of travel of the web, whereby regardless of variations in the traveling speed of the label tape, labels can be affixed to the traveling web without causing tearing and wrinkling of the labels and the traveling web. 
     In the printing, web coating or web laminating process, various defects occur. Therefore, it is required to mark instantaneously the positions of defects of a traveling web so that the positions and types of defects can be determined. Unless such marking is employed, the positions and types of defects cannot be found after the web has been rolled. Therefore, a slip or the like recording the positions and types of defects must be prepared by the operator in the printing factory or the like and be sent to the succeeding station of the production line for checking. However, if the slip or the like is lost, it becomes impossible to detect the positions and know the types of defects. 
     The conventional methods for indicating defects of a traveling web are (1) marking by spraying, (2) marking with ink rolls, felt pens or stamps, (3) inserting a strip of paper, (4) marking with notches, (5) marking with an ink jet and (6) affixing labels. Such methods have their inherent merits and demerits. In the case of (1), the spray nozzle tends to be clogged; ink drips; a portion without defect is marked; and it is difficult to find the positions of defects from the side face when the web is rolled. In the case of (2), marked positions cannot be clearly distinguished and it is impossible to find the positions of defects from the side face of the rolled web. In the case of (3), it is difficult to exactly detect the defects; the defects within the interior of the rolled web cannot be found; and when the rolled web is unrolled, the strip of paper is dropped. In the case of (4), the web is partially cut out and it is impossible to find the defects from the side face of the rolled web. In the case of (5), the ink nozzle tends to be clogged because ink is dried and it is impossible to find the defects from the side face of the rolled web. In the case of (6), the web and the labels tend to be torn off or wrinkled because the traveling speed of the web is not equal to the speed at which the label is pushed forward against the surface of the web. However, this method of affixing labels to the web is considered most advantageous among the above stated defect indicating methods. 
     In the conventional apparatus for affixing a label to a traveling web, the label must be pushed against the web at the same component traveling speed as the web in the instant of affixing operation. It follows therefore that when the traveling speed of the web varies, the component speed in the direction of the movement of the web at which the label is pushed forward must be varied accordingly. As a result, the labeling apparatus is very complicated in construction. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an apparatus for affixing labels to a moving web wherein it is not necessary to push the labels against the web with the same component traveling speed along the web as the moving web, and wherein the labels can be affixed to the web regardless of its traveling speed. 
     According to the present invention, the type of defect detected is marked on a label of a label tape which is held stationary, and then the base strip of the label tape is advanced and abruptly reversed in its moving direction, whereby the label removably secured to the surface of the base strip is partially separated from the base strip due to the stiffness of the label. The label thus partially separated is then pressed against the moving web. At the instant the label is pressed against the web, abrupt variation in tension of the label tape occurs, which variation is relieved or absorbed by a movement of the label tape in the direction of movement of the web. As a result, regardless of the traveling speed of the web, the label can be affixed thereto without causing adverse effects such as tearing and wrinkling of the label and the web. The movement of the label tape in the direction of movement of the web is made possible by means of a resiliently supported movable roller around which the label tape is passed. 
     The features which are believed to be characteristic of the present invention are set forth in the appended claims. The invention itself, however, both as to its organization and method of operation, will best be understood from the following detailed description taken in connection with the attached drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevation, partly in section, of a first form of the apparatus in accordance with the present invention; 
     FIGS. 2A, 2B, 2C and 2D are fragmentary side views showing successive steps for affixing a label to a traveling web; 
     FIG. 3 is a fragmentary side elevation showing a modification of the apparatus of FIG. 1; 
     FIG. 4 is a fragmentary side elevation showing another modification of the apparatus of FIG. 1; 
     FIG. 5 is a perspective view showing a label affixed to a web; 
     FIG. 6 is a perspective view of a web roll with labels affixed; 
     FIG. 7 is a perspective view of a second form of the apparatus in accordance with the present invention; 
     FIG. 8 is a side elevation, partly in section, of the apparatus shown in FIG. 7; 
     FIG. 9 is a fragmentary side view with a supporting plate removed to show a state in which the piston rod of a pneumatic cylinder is retracted; and 
     FIG. 10 is a view similar to FIG. 9 but showing a state in which the piston rod is advanced. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, the device for affixing labels to a moving web shown therein has a machine frame 2, to which a pair of upper horizontal brackets 3 (only one can be seen) and a pair of lower horizontal brackets 4 (only one can be seen) are fixed. The upper brackets 3 are connected by means of two guide rods 5 by which a vertical supporting plate 6 is supported at the upper part thereof. The supporting plate 6 is movable along the guide rods 5 and can be locked in any adjusted position along the guide rods 5. 
     A label tape supply roll 11 is supported rotatably on the supporting plate 6 by means of a shaft 7. A label tape c consisting of a base strip a and labels b removably affixed thereto is wound around the label tape supply roll 11. The label tape c paid out from the supply roll 11 is passed around a guide roller 12 and a movable swing roller 13 toward the lower edge 14a of a vertically extending separating plate 14. The guide roller 12 is rotatably mounted on the supporting plate 6 while the separating plate 14 is fixed to the supporting plate 6. At the edge 14a of the separating plate 14 the base strip a of the label tape c is reversed in direction; that is, extended upward and passes between a drive roller 15 and a pinch roller 16, which are supported on the supporting plate 6, and is wound around a take-up roller 17. An electromagnetic brake 18 is provided on the shaft 7 of the supply roll 11. The swing roller 13 is mounted at one end of a swing arm 19 the other end of which is rotatably supported by the shaft 7 of the supply roll 11. A spring 20 is disposed between the arm 19 and a pin 8 on the supporting plate 6. A limit switch 21 is mounted on the supporting plate 6 adjacent to the upper edge of the arm 19. 
     The other end of the swing arm 19 may be pivotally supported on a pivot shaft, other than the shaft 7, on the supporting plate 6, but it is advantageous that the other end of the arm 19 be pivoted on the shaft 7 of the supply roll 11 because interference of the swing roller 13 with the supply roll 11 can be avoided during the movement of the swing roller 13 and the number of component parts can be minimized. 
     A stamping unit 22 is disposed on the supporting plate 6 adjacent to the separating plate 14 and consists of stamps 24 (three stamps being shown) which are actuated by pneumatic cylinders 23. 
     A web d to which the labels b are to be affixed is guided by a web guide roller 25 which is supported on the brackets 4 and disposed adjacent to the edge 14a of the separating plate 14 in opposed relationship with the stamping unit 22. A labelling or pressure roller 26 is provided to press a label b at one time against the web guide roller 25. The pressure roller 26 is moved in operation to the left as viewed in FIG. 1 by means of a pneumatic cylinder 27 on the supporting plate 6. 
     Instead of the electromagnetic brake 18 which applies braking force to the supply roll 11, a nip roller 28 and an inertia roller 29 having a great inertia may be used as shown in FIG. 3 to apply braking force to the label tape c. Furthermore, as shown in FIG. 4, a braking roller 30 and a guide roller 31 may be used instead of the electromagnetic brake 18. In this case, a pneumatic cylinder 32 is connected to the swing arm 19 to cause the latter to return from a downwardly swung position to its normal horizontal position shown in FIG. 4. 
     The stamping unit 22 is in opposed relationship with the separating plate 14 and its stamps 24 can be extended out of or retracted into the casing of the stamp unit 22 by the pneumatic cylinders 13. The stamps 24 have different colors, symbols, letters or characters. 
     Next the mode of operation of the above described apparatus will be described. As shown in FIG. 1, the label tape c is supplied from the supply roll 11, is guided by the guide roller 12 and the swing roller 13 and reaches the separating plate 14. At the separating plate 14, the label tape c is abruptly reversed in direction so that the labels b are separated successively from the base strip a due to their stiffness. The base strip a passes between the drive roller 15 and the pinch roller 16 and is wound around the take-up roller 17. 
     The label tape c is normally held stationary; that is, the electromagnetic brake 18 holds the supply roll 11 non-rotatable, while the web d, such as a printed sheet of paper, a coated sheet or a laminated sheet, is supplied continuously past the web guide roller 25. 
     As shown in FIG. 2A, when the web d has any defect (which is detected automatically or by visual inspection), depending upon the type of defect, one of the stamps 24 is thrust by the pneumatic cylinder 23 so that a predetermined color, symbol, letter or character is stamped on the surface of the label b which is held stationary on the separating plate 14. After stamping, the base strip a is pulled upwardly by a certain length by the drive roller 15, but the supply roll 11 is held non-rotatable by the electromagnetic brake 18 so that the swing roller 13 is caused to move downward against the force of the spring 20 and consequently the label b is separated from the base strip a which is reversed in direction at the edge 14a of the separating plate 14. In this case, the label b is separated from the base strip a due to the stiffness of the label b, but, as shown in FIG. 2B, the label b is only partially affixed to the base strip a. The back surface (that is, the surface opposite to the surface upon which is stamped a mark such as a color, symbol, letter or character as described above) is coated with an adhesive layer. Therefore, when the labelling or pressure roller 26 is pressed immediately thereafter against the web guide roller 25, the label b is completely separated from the base strip a and is affixed to the web d which is being moved as shown in FIG. 2C. In this case, the position at which the label b is affixed is approximately the same as the position of the defect on the web d. An abrupt change in tension caused in the label tape c when the label b is separated from the base strip a is relieved and absorbed because the swing roller 13 which guides the label tape c is allowed to move downward together with the swing arm 19 against the force of the spring 20. In connection with the operation of the pressure roller 26, the brake 18 is released. After the label b is affixed to the web d, the swing roller 13 is caused to rise as shown in FIG. 2D under the force of the spring 20 acting on the swing arm 19. Upon arriving at the horizontal position, the arm 19 engages at its upper edge with the limit switch 21 (See FIG. 1) whereby the electromagnetic brake 18 is energized so that the label tape c, which has been paid out from the supply roll 11 by a length sufficient to bring the swing roller 13 to its initial position, is prevented from being supplied further. It will be understood that the limit switch 21 disposed adjacent to the upper edge of the arm 19 in its normal position to issue a signal for energizing the electromagnetic brake 18 functions to determine the length of the label tape c to be paid out from the supply roll 11. 
     In the modification shown in FIG. 3 using the nip roller 28 and the inertia roller 29, the label tape c passes therebetween, and when the label tape c moves suddenly, the inertia roller 29 applies brake thereto. In the modification shown in FIG. 4, the label tape c passes between the brake roller 30 and the guide roller 31. When the label tape c moves suddenly, the brake roller 30, which is being braked, applies brake thereto. The swing roller 13 which has been swung downwardly can be returned to its initial position by means of the pneumatic cylinder 32, overcoming the braking action of the brake roll 30. In this case, it is not necessary to normally interconnect the swing arm 19 and the cylinder 32. For instance, when the label b is pressed against the web d, the arm 19 must be kept free to swing resisting the force of the spring 20 so that a sudden change in tension of the label tape c can be relieved and absorbed. The pneumatic cylinder 32 can be connected to the arm 19 after the label b has been affixed to the web d to cause the arm 19 to move back to its normal position. 
     In FIG. 5 a part of the web d is shown with a label b affixed thereto. The label b is affixed to the web d in about a half of its area, and a mark 34, such as a colored mark, symbol, letter or character, is stamped on the surface of the label b extending out of the web d. For example, four types of defects can be distinguished by the color of the label b itself and three marks stamped by the three stamps 24. 
     FIG. 6 shows a roll of the web d with labels b affixed. It is seen that the marked labels b are extended from the side face of the roll. 
     As described hereinbefore, the supporting plate 6 carrying the mechanisms for paying out the label tape c, for stamping and for affixing the stamped label b is adjustably movable along the guide rods 5. Because of this construction, the position of affixing the label b to the web d can be changed depending upon the width of the web d. 
     In FIGS. 7, 8, 9 and 10 a second embodiment of the present invention is shown which is substantially similar in construction and mode of operation to the first embodiment described above except for the following features. First, as best shown in FIG. 7, the arm 19 which carries the swing roller 13 is disposed within a cover 40, that is, behind the supporting plate 6. Therefore, the shaft 13a of the swing roller 13 is extended through a large-diameter hole 41 formed through the supporting plate 6 so that the swing roller 13 may swing downwardly. 
     Second, as best shown in FIGS. 8, 9 and 10, a vertical lever 43 is disposed behind the supporting plate 6 and within the cover 40 and is pivoted at its intermediate part by a pivot pin 44 to the supporting plate 6. The labelling or pressure roller 26 is rotatably carried at the lower end of the vertical lever 43 while an engagement roller 45 is rotatably carried at the upper end of the lever 43 and engages with a roller 46 on the free end of the arm 19 as best shown in FIG. 9. The piston rod 48 of a pneumatic cylinder 27A is pivoted with a pivot pin 49 to the lever 43, and the proximal end of the cylinder 27A is pivoted to the supporting plate 6 by a pivot pin 50. 
     Therefore, as the piston rod 48 of the cylinder 27A is extended as shown in FIG. 10, the lever 43 is rotated about the pivot pin 44 in the clockwise direction so that the labelling or pressure roller 26 is caused to press against the web guide roller 25. When the piston rod 48 of the cylinder 27A is retracted, the lever 43 returns to its upright position so that the roller 45 engages with the roller 46 and the arm 19 is maintained in its substantially horizontal position as best shown in FIG. 9. 
     It is necessary to maintain this substantially horizontal position of the swing arm 19 by the engagement of the rollers 45 and 46 bacause without this engagement the swing roller 13 would be caused to move downward when the base strip a is pulled by the drive roller 15. As described hereinbefore, when the piston rod 48 of the cylinder 27A is advanced to cause the pressure roller 26 to be pressed against the web guide roller 25 for the labelling, the roller 45 at the top of the lever 43 is disengaged instantaneously from the roller 46, whereby the swing roller 13 is allowed to move downwardly to absorb the abrupt change in tension of the label tape c as in the case of the first embodiment of the invention.