Abstract:
An apparatus and method for splicing photographic films is disclosed, where the films are conveyed along a path and supported by a track element. Upon being positioned to receive a splice, the films are clamped between a movable splice pad and the track clement. The clamping action produced by the movable splice pad substantially eliminates the problem of film foldovers caused by curling at the trailing end of a film. A splice head is lowered to apply a splice tape to the films, thereby forming the splice. The films are spliced together in a flattened state, producing a continuous web of film which can be wound onto a roll or core for further processing.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention resides in the field of photographic processing systems, and more particularly relates to a method and apparatus for splicing photographic films onto a common roll or core which is to be developed in a photographic processing machine. 
     2. Background 
     Film processing systems and, in particular, film splicing and desplicing machines, are known in the art. Such machines are commonly used in central film laboratories to achieve efficiencies in film development and processing operations. A plurality of rolls of film can be developed more efficiently by splicing together the film on a common roll, developing the film, and then desplicing the film to separate it into the original rolls, as compared with processing the rolls separately. Splicing machines and processes are particularly useful with Advanced Photo System (APS) film. With APS film, the film is removed from each cartridge and spliced with other rolls of film for development. After being developed, the web of film is despliced and a continuous set of negatives is reinserted in each corresponding cartridge. Thus, APS film customarily is processed in a manner different from 135 film (for which the film process usually involves cutting the negatives in strips and returning the cut negatives to the customer); with APS film, the negatives are returned as a continuous roll inside the original film cartridge. Splicing and desplicing operations are important steps in the processing of APS film, but certain problems are prevalent in conventional splicing processes. The tendency of the film tail to curl has resulted in a problem of film “foldover,” as explained below, which has not heretofore been adequately resolved. 
     In a splicing operation, a trailing end of a first film is spliced to a leading end of a second film. A typical arrangement is shown in FIG. 6, where the trailing end  82  of the first film  80  is spliced to the leading end  86  of the second film  84  using a splice tape  88 . FIG. 7 is a cross-sectional view of a splicing operation including a reciprocating splice head  90  which is lowered to fix the splice tape  88  over the trailing end of the film  80  and the leading end of the film  84 . As shown in FIG. 7, the trailing end  82  of the film  80 , which was previously wound tightly around the core of a film cartridge, tends to retain some curl at its end thereof. When the splice head  90  is lowered to apply the splice tape  88 , any portion of the film  80  positioned under the splice head becomes part of the splice. Accordingly, if the trailing edge  82  of the film  80  exhibits some curl, this curved tail portion becomes sandwiched in the splice. In FIG. 7, the film  80  has been spliced in the folded condition, resulting in an added splice thickness in the region of the fold and thus film “foldover.” This added thickness is undesirable and creates a pressure mark on successive wraps of the film wound onto a reel or core. The pressure mark is detrimental to other operations in the film developing process, for example showing up on negatives as a visible mark in the image area after developing. The pressure mark will also be visible on any prints made from the negative. 
     Previous attempts to solve the above-described problem involved use of the following implements: (1) an airjet, or (2) a mechanical element to bend back the film. Air jets are very expensive and difficult to maintain because tight tolerances are required. The aerodynamic effects of the air stream and the angle at which the air stream is positioned are important factors which, if not provided almost exactly in accordance with film feed requirements, can result in the film strip eluding the air stream, thus rendering the airjet useless. Mechanical “bending” elements can cause significant damage to the surface of the film by, for example, causing the film surface to abrade or the emulsion to crack or break off. Further, such mechanical elements are not always effective in “catching” the curled tail section of the film. 
     U.S. Pat. No. 5,656,125 (&#39;125 patent) discloses a film splicer including a reciprocating head  34  opposed by a pad  36 , where films  12  are conveyed therebetween, and the head  34  is lowered to fix a splicing tape  39  to the films  12 . The &#39;125 patent is directed to the problem of the splicing tape tending to adhere to the pad during a splicing operation. As shown in FIG. 1 of the &#39;125 patent, e.g., a concave portion  38  is cut in the pad  36  so as to avoid contact between the tape  39  and the pad  36  during splicing. The &#39;125 patent does not address the film “foldover” problem described herein. 
     SUMMARY OF THE INVENTION 
     We have found that an improved splice can be formed between photographic films substantially without resulting in film “foldover” or causing the formation of damaging pressure marks. An apparatus and method of forming a splice according to the present invention includes a movable anvil plate (i.e. splice pad) which clamps two film strips to a film track element where a splice is to be formed, thereby straightening any curl in the film and providing a surface to receive a splice head. The film track element provides support to the edges of the films from above and thus eliminates some curl or foldover. A cylinder then actuates the splice pad and moves the splice pad toward the film track element to clamp the films therebetween for receiving the splice head. A separate splice head cylinder is actuated, advancing the splice head downward toward the splice pad to form a splice. In a preferred embodiment, the splice head continues moving downward to force the splice pad down toward its rest position. The splice head preferably engages with the splice head for a sufficient time to adhere a splice tape to the two film strips. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a fuller understanding of the nature of the present invention, reference is made to the following detailed description taken in conjunction with the accompanying drawing figures wherein like reference characters denote corresponding parts throughout the several views and wherein: 
     FIG. 1 is a cross-sectional side view of a splicing apparatus including a movable splice pad and a splice head of the present invention; 
     FIG. 2 is a top plan view of the splicing apparatus of FIG. 1; 
     FIG. 3 is cross-sectional front view of the movable splice pad of the present invention; 
     FIG. 4 is an enlarged front view of a portion of the movable splice pad of FIG. 3; 
     FIG. 5 is an exploded parts view of the movable splice pad of the present invention; 
     FIG. 6 is a top view of first and second film strips joined together by a splicing tape, in accordance with the present invention; 
     FIG. 7 is a schematic depiction of film foldover as encountered in prior art splicing devices; and 
     FIG. 8 is a schematic depiction of a first film strip decurled and spliced together with a second film strip, in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 illustrates a photographic film splicer configured and arranged around a film track element  10 , the film track element for guiding one or more films  26  along a horizontal path through the film splicer. The film splicer includes a splice head  12  preferably arranged above the film path, and a splice pad assembly  21  with a splice pad  20  preferably arranged below the film path. The splice head  12  and splice pad  20  are initially positioned outside the film track element  10 , i.e. preferably above and below the horizontal path, respectively. The splice head  12  is supported from above by a support plate  14 , the support plate being attached to a shaft  15  by a linear bearing  16 . An air cylinder  17  is preferably positioned on a support  18  and operably connected to the support plate  14  via the shaft  15 . The air cylinder controls up and down movement of the support plate  14  and thus moves the splice head  12  into contact with first and second films on the path below to form a splice. Splice tape is supplied to the splice head  12  to be heat sealed on the films, where the splice tape is preferably a heat activated adhesive tape. The splice tape can be a continuous length of tape which is cut by the splice head  12 ; alternatively, individual pre-cut lengths of tape can be fed to the splice head  12 . Arranged below the film path, the splice pad  20  is movable toward and away from the splice head  12  to thereby clamp the films to the film track element  10  prior to forming the splice. 
     FIG. 6 illustrates a typical arrangement of a first film strip  80  and a second film strip  84  which are spliced together by a splice tape  88 . A trailing end  82  of the first film strip can include a tapered portion in accordance with the standard specifications of APS film. A leading end  86  of the second film strip is pointed, which facilitates joining to the tapered trailing end of the first film strip. Alternatively, neither or both ends can be pointed or tapered, and for example, both ends can be straight and flat. The preferred pointed leading end of the second film strip is also standard with APS films and is useful for feeding the film. 
     FIG. 7 illustrates a typical problem encountered with prior art film splicing devices, whereby the trailing end of the first film strip naturally tends to curl, since the trailing end  82  was previously wound tightly around the core of a film cartridge. In prior art devices, this curled tail section of the film strip tends to fold onto itself. When a splice head  90  is lowered to fix a splice tape  88  over the first and second film strips, the tail section becomes folded under the splice, thus resulting in the problem of film “foldover.” 
     In accordance with the method and apparatus of the present invention, film foldover is substantially eliminated. The film is decurled prior to the lowering of the splice head and application of the splice tape  88  to form the splice. As discussed below, the film strips (films) are clamped to the film track element, thereby removing any curl from the film tail and producing a good splice, as shown in FIG.  8 . 
     With reference to FIGS. 1 and 2, the films  26  (corresponding to film strips  80  and  84 ) are conveyed along the film path using conventional rollers (not shown) and precisely positioned under the splice head  12  using a conventional array of sensors or other known positioning elements (not shown). As shown in FIG. 6, the leading end  86  of the second film strip can be brought to within a short distance of the trailing end  82  of the first film strip. In a particular embodiment, this distance or gap can be approximately 3.25 mm to a tolerance of approximately ±0.75 mm. The splice tape  88  is applied centrally over this gap to within approximately 0.5 mm in either direction. This gap between the films preferably is positioned over a cut-out area of the splice pad, as discussed below with reference to FIG.  5 . 
     As shown in FIGS. 3 and 4, the film path includes the film track element  10  positioned along the track to guide the films  26  from immediately above. A small rim area  11  on either side of the film track element  10  can contact the film along the edges as it is being conveyed through the film processing apparatus. The rim area  11  only touches the film immediately along the edges thereof, in order to prevent damage to the emulsion area of the film. 
     When the leading end of a first film and the trailing end of a second film are positioned under the splice head  12 , the splice pad is actuated and a cylinder  22  moves the splice pad  20  toward the film track element  10 . The splice pad assembly  21  is shown in detail in FIG.  5 . The splice pad assembly includes a main body  40  having a central bore  41  which can include a bearing (not shown) for receiving the cylinder  22 . The main body preferably is positioned outside the film path and generally remains stationary during a splicing operation. Positioned above the main body is a pad insert section  44  having a pin  23  for receiving the cylinder  22 . The splice pad  20  is positioned above the pad insert section  44  and fastened to the splice pad by a screw  48  or other standard connecting element. The splice pad  20  and pad insert section  44  rest above the main body  40  and can move up and down as the pin  23  is forced by the cylinder  22 . 
     The splice pad  20  preferably includes a smooth upper surface in contact with the films  26  during splicing. The splice pad  20  is received in the film track element  10  above to thereby clamp the films  26  as they are being conveyed along a path (see, e.g., FIG.  2 ). On its upper surface, the splice pad  20  includes an elevated track guide  50  which mates with the film track element  10  to fix the films  26  for splicing. As seen in FIG. 4, the elevated track guide  50  fits within the rim area  11  of the film track element to clamp the films therein. The track guide  50  includes a cut-out area  52  for receiving a “sticky” side of the splice tape, thereby preventing the splice tape from adhering to the splice pad  20 . 
     In operation, first and second films  26  are conveyed to an appropriate position immediately below the splice head  12  to receive a splice tape. An ideal position is illustrated in FIG. 8, in which the films  26  are represented by first film strip  80  and second film strip  84 . A small gap exists between the film strips  80  and  84  to prevent film overlap and thus receive the splice tape  88 . Preferably, this gap is centered over the cutout area  52  in the track guide  50 . The films are conveyed until they stop at desired positions. When thus positioned, the films are supported along their edges from above by the track element  10 . The track element functions to eliminate some foldover or curl which can be present near the trailing end of the first film by providing support from above. The cylinder  22  is then actuated, causing the splice pad  20  to move upwardly toward the film track element. The cylinder  22  clamps the films against the film track element  10 . This clamping action substantially eliminates any curl or film foldover that can be present near the trailing end of the first film. The films to be joined are essentially flat, and the splice head  12  is then lowered, as shown in FIG.  8 . 
     To lower the splice head  12 , the splice head cylinder  17  is actuated, causing the plate  14  and the splice head  12  to move downwardly toward the film track element  10 . As shown in FIGS. 2 and 4, the splice head  12  moves downward while centered relative to the bore  24  in the film track element to thereby apply a splice tape and heat seal the tape onto the films  26 . Under the heat and pressure of the splice head  12 , the splice tape is applied to form a splice between the films, as shown, e.g., in FIG.  8 . 
     Preferably, the cylinder  17  operating the splice head is driven downward with a force sufficient to overcome the cylinder  22  operating the splice pad. As the splice head  12  contacts the film to form the splice, the splice head continues moving downward and forces the splice pad  20  downward. This continued downward movement allows further time for a satisfactory heat seal to form between the films, thereby ensuring that the splice tape will remain adhered to the two films. The cylinder  17  can continue driving the splice head  12  and the splice pad  20  downward until the splice pad  20  is at its original rest position. Alternatively, the cylinder  17  can continue moving downward for a preset length of time or until the splice pad reaches a predetermined position. The cylinder  17  then releases from the splice/splice pad and retracts to its original rest position. 
     In an alternative embodiment, the splice head can retract after forming a splice which joins the films  26 . The splice pad  20  then moves downward to prevent interference with the now joined films  26  being conveyed past the splicing section. In this embodiment, the splice head cylinder  17  and the splice pad cylinder  22  can be of approximately the same size, such that the forces exerted by the cylinders  17  and  22  are approximately equal. It is not necessary that the splice head cylinder  17  force the splice pad  20  down after the splice has formed. 
     In a further alternative embodiment, the splice pad cylinder  22  can be operated with a greater force than the splice head cylinder  17 . In such an arrangement, after the splice head  12  is lowered into contact with the films  26  being joined, a portion of the splice pad (e.g. the elevated track guide  50 ) detachable from the remainder of the splice pad continues moving upward, and the cylinder  22  overpowers the splice head cylinder  17 . Additional time can then be provided so that a satisfactory heat seal is formed. When the splice head  12  and support plate  14  reach a predetermined level (e.g. the rest position of the splice head), the cylinder  22  can be retracted. 
     In a still further alternative embodiment, a different arrangement reversing the positions of the splice head and the splice pad can be used. For example, the orientation of the film track element can be reversed, such that the heat seal is applied from a position beneath the film track, instead of above it. 
     The above-described splice head and movable splice pad can be retrofitted to existing photographic processing machines, in some cases simply by replacing the fixed splice pad (anvil pad) present in conventional splicing arrangements. A tracking element must also be provided which clamps with the splice pad to eliminate any curl present in the film. 
     Although the invention has been described in detail including the preferred embodiments thereof, such description is for illustrative purposes only, and it is to be understood that changes and variations including improvements may be made by those skilled in the art without departing from the spirit or scope of the following claims.