Method for dispensing adhesive transfer tape for engagement with a moving strip of photographic film prints
This is a division of application Ser. No. 505,253, filed Sept. 12, 1974, now U.S. Pat. No. 4,001,073. 
    
    
     BACKGROUND OF THE INVENTION 
     Commercial photographic print developers have heretofore produced individual photographic prints by first developing and printing several customers&#39; roll film on long continuous strips of photosensitive paper. These strips are then fed through a film cutter for cutting into individual prints. The continuous strips are usually provided with indexing holes, one for each print, such that the cutter can properly align each print prior to severance from the strip. The cutter also trims each print to remove the index hole. The developed print strip typically is wound into a roll from which it is drawn intermittantly into the film cutter by the cutter indexing device. In order to minimize the likelihood of improper indexing, the roll desirably is unwound by the cutter indexing mechanism so that little tension is applied to the print strip. 
     It has become desirable from the customer&#39;s point of view to be able to mount photographic prints without use of external aids such as corner tabs or the messiness of liquid cement. Until the present invention, however, commercial, mass production processing of roll film into prints has not permitted the commercial film developer to offer the customer a better means of mounting photographic prints. 
     SUMMARY OF THE INVENTION 
     The present invention enables the commercial film developer to automatically apply continuous strips of pressure-sensitive adhesive transfer tape to the back of a continuous strip of photographic prints which, upon severance into individual photographic prints, yield prints with a pressure-sensitive adhesive transfer tape backing. The tape includes a cover ply which when peeled off leaves strip adhesive adhered to the print and exposed for mounting. Thus, the customer may now mount photographic prints without any inconvenience. The present invention also permits the application of pressure-sensitive adhesive transfer tape during the photographic print strip cutting process without disrupting the proper indexing or cutting of the prints advanced through the cutter, and without causing curling of the individual severed prints. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a film cutter attachment for applying strips of pressure-sensitive adhesive transfer tape to a continuous roll of photographic film prints; 
     FIG. 2 is a side view, partially in section, of the FIG. 1 cutter attachment; 
     FIG. 3 is a cross section taken along the line 3--3 in FIG. 1; 
     FIG. 4 is a cross section taken along the line 4--4 in FIG. 1; 
     FIG. 5 is a perspective view of a portion of a strip of photographic prints depicting strips of adhesive transfer tape applied to the backside of the print strip; 
     FIG. 6 is a schematic depicting one aspect of the process of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The illustrated apparatus for dispensing a continuous strip of adhesive transfer tape and applying it to the back of a continuous strip of developed photographic prints is designed and constructed as an attachment to existing film cutters; however, it may be incorporated into a combination film cutting and tape applicator system depicted in FIG. 6. The film cutter attachment generally designated 10 is mounted upon the supply end of a film cutter 12. The film cutters with which this invention is particularly useful process a roll of developed photographic prints 14 on which several customer&#39;s roll film is printed. As depicted in FIG. 6, a continuous photographic print strip 14a is progressively unwound from the photographic print roll 14, drawn under a pressure roller 16 on the film cutter, and then advanced by an intermittantly operated indexing device 20 to a film cutter 22. The continuous photographic print strip 14a typically is provided with indexing holes (not shown), one for each print, in which the cutter indexing device 20 is engageable. The film cutter 22 severs each print from the photographic print strip 14a and trims each print to remove the index hole. The severed prints are collected in a receptacle 24 at the output end of the film cutter 12. Cutter units with which this invention may be used include those manufactured by Kodak Corporation and Pako Corporation. 
     Referring to FIG. 1, the film cutter attachment of this invention comprises two independently operable tape dispensing units 24 and 26, each mounting a roll of adhesive transfer tape, and a guide bar 27 for simultaneously positioning the tapes in mutually parallel registry with the back of the photographic print strip 14a as it is drawn into the film cutter 12. The number of tape dispensing units, of course, may be varied, if desired. As will also be appreciated, this invention may be used to apply one or more continuous tape strips to the back of a strip of developed photographic film prints as the latter is being wound into a roll. This roll thereafter is mounted in a film cutter and cut into individual prints. 
     Tape suitable for use in this invention is manufactured by Minnesota Mining and Manufacturing Company. It comprises a thin, silicone treated cover ply upon one side of which is deposited a layer of pressure-sensitive adhesive. Following pressure application of the tape to a substrate, such as the back of a strip of photographic paper, the cover ply can be peeled off leaving the adhesive adhered to the substrate and exposed. 
     The tapes of each dispensing unit are unwound in synchronism with the advancement of the print strip 14a during the cutting process and are applied progressively in mutually parallel relationship (see FIGS. 4 and 5) to the back of the photographic print strip 14a as it is unwound from the print roll 14 and drawn intermittantly underneath the cutter pressure roller 16 by the cutter indexing device 20. The print strip 14a with the adhesive tapes adhered thereto is then passed between two mutually opposed edge channels 32 along which it is advanced to the cutter 22 by the indexing device 20. The cutter simultaneously severs the individual prints and the respective portions of the adhesive tapes adhered thereto. 
     The tape dispensing units 24 and 26 are generally similar. The right tape dispensing unit 26 is described herein with reference numerals. Like parts of the left tape dispensing unit 24 are designated with the same reference numerals primed. As depicted in FIG. 1, a stepping motor 30 mounted on the outside surface of a vertical, generally square mounting plate 33 drives a horizontal output shaft 34 which extends through the mounting plate 33. A roll 36 of the above-mentioned adhesive transfer tape is mounted on shaft 34 adjacent the inside surface of the mounting plate 33. An arm 38 weighted by a small weight 38a is pivotally supported by a horizontal pivot pin 39 projecting from the outside surface of the mounting plate 33, relative to which the arm can swing vertically, as depicted in FIG. 2. Upper and lower electrical limit switches 42 and 44 engage the arm 38 when it reaches its upper and lower limits of travel, depicted in solid and broken lines, respectively, in FIG. 2. These switches are connected by wires 46 to a junction connector 48 (FIG. 1) which is interconnected with the cutter and stepping motor electrical control systems. A stop peg 50 abuts against and supports the arm 38 when it swings to its lower position. Lower and upper rollers 51 and 52 project inwardly from the rear lower and upper corners of the mounting plate 33. 
     The mounting plates 33 and 33&#39; each are pivotally interconnected by upper and lower vertical pivot pins 54 and 56 with a vertical adaptor plate 58 to swing horizontally between an open position, depicted in broken lines in FIG. 1, in which they avert from one another and a closed position in which they are adjacent and mutually oppose each other. In the mounting plate open position, the tape rolls 36 and 36&#39; are exposed for reloading. It will be recognized that the construction of the adaptor plate 58 may vary depending upon the type of film cutter with which this invention is used. 
     As best shown in FIG. 1 the guide bar 27 forms a bridge between the upper edges of the dispensing units 24 and 26 and the supply end of the film cutter 12. The guide bar 27 extends through a square opening in the upper portion of the adaptor plate 58 to which it is secured by a brace 60. 
     As shown in FIGS. 1 and 2, the unwound strip portions 36a and 36a&#39; of the tape rolls 36 and 36&#39; are trained about the undersides of the arm rollers 40 and 40&#39;, lower rollers 51 and 51&#39; and then over the upper rollers 52 and 52&#39; with the above-described cover ply on each tape facing and engaging its associated roller. Upon passing over the latter rollers, the tapes are oriented substantially in the plane of top surface of the film cutter 12 as they pass along the bottom of mutually parallel U-shaped channels 62 and 64 (FIG. 3) in the guide bar 27. As best shown in FIG. 3, the tapes are maintained in flattened, generally horizontal conditions and pass underneath inclined tape stops 65 as they travel along these channels, the lower portions of which provide mutually opposed portions adapted to receive the longitudinal edge portions of the tape. The inclined tape stops 65 (see also FIGS. 1 and 2) are pivotally supported from the adapter plate in order to slidably engage the upper surfaces of the tapes and prevent them from becoming disengaged from the dispensing unit rollers if they are disconnected or severed from the print strip 14a before passing into the film cutter 12. As the tapes emerge from the forward ends of the guide bar channels 62 and 64, they are positioned with their exposed adhesive sides opposed to and in substantially face to face registry with the back of the unwound print strip 14a as it is drawn to the cutter pressure roller 16. 
     After loading fresh tape rolls into the tape dispensing units 24 and 26, the operator trains the tape about the dispensing unit rollers and engages the tapes within the guide bar channels 62 and 64 with the end of each tape projecting from the forward end of the guide bar 27. The operator then manually applies pressure to the superimposed photographic print and tape portions to bring them into adhesive engagement with each other. Thereafter, the cutter pressure roller 16 applies pressure to adhesively join together the superimposed photographic print and tape portions as they are automatically advanced conjointly to the film cutter 22 by the cutter indexing device 20. 
     The dispensing unit arms 38 and 38&#39; control the tension in the tape strips 36a and 36a&#39; as they are dispensed and applied to the photographic print strip 14a. As the tapes are intermittantly drawn into the cutter conjointly with the photographic print strip 14a, the arms 38 and 38&#39; swing up and down as the tape loops between the tape rolls 36 and 36&#39; and their respective lower rollers 51 and 51&#39; vary in length. When one or both arms reach their upper positions (FIG. 2), they engage and close their respectively associated upper limit switches 42 and 42&#39;. These switches cause the tape dispensing stepping motors 30 and 30&#39; to be energized to dispense additional tape until the lengths of the tape loops are increased sufficiently to allow the arms 38 and 38&#39; to swing downwardly out of engagement with the upper limit switches 42 and 42&#39;. When the tape supply is exhausted, the arms swing to their lower positions at which they engage and close the lower limit switches 44 and 44&#39;. These switches, which are connected in the cutter electrical control circuit, cause the cutter to be turned off. 
     Thus it will be seen that the tape strips 36a and 36a&#39; are tensioned by the dispensing unit arms 38 and 38&#39; as necessary to guide the tapes during dispensing. These arms also cause additional amounts of tape to be dispensed automatically, substantially simultaneously and in synchronism with intermittant movement of the photographic print strip 14a so that the tape strips remain relatively slack as they are drawn to the film cutter by the cutter indexing device 20. Inasmuch as the cutter indexing device 20 does not have to pull additional tape from the tape rolls 36 and 36&#39;, erratic or jerky motion in the tape and photographic print strips is minimized as they are drawn together and advanced to the film cutter 22. This provides greater continuity of movement of the tape and photographic print strips, and hence ensures accurate print cutting by the film cutter 22. Curling of the severed prints is minimized or eliminated by selection of an arm weight sufficient to maintain engagement and alignment of the tapes as they are trained about the dispensing unit rollers during dispensing; but light enough not to stretch the tapes, or to impose excessive drag on the photographic print strip 14a as it is unwound from the print roll 14 and drawn under the cutter pressure roller 16. 
     While the preferred embodiment of the invention has been illustrated and described herein, it should be understood that variations will be apparent to one skilled in the art. For example, the film cutter attachment of this invention may be used with film cutters which do not include a pressure roller 16. In such applications the print and tape strips are drawn adequately together by the film cutter channels 32; however, for more positive engagement, the forward end of the guide bar 27 may be positioned in sliding engagement with the back of the print strip 14a so that the tape strips 36a and 36a&#39; are brought into engagement with the back of the print strip 14a as it sweeps past the forward end of the guide bar 27. Accordingly, the invention is not to be limited to the specific embodiment illustrated.