Film unloading and handling mechanism
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to film processing apparatus and, more particularly, to a mechanism for unloading exposed film from a film cassette in a lighted area for splicing and subsequent processing. 
     2. Description of the Prior Art 
     Film splicers for joining individual lengths of film end-to-end are in common use in the film processing industry. Although such splicers greatly improve the efficiency of film processing in comparison to processing individual lengths of film, they nevertheless suffer from a variety of problems. 
     The initial problem is encountered at the front end of the splicer when the film is being unloaded from a cartridge. To prevent the film from being inadvertently exposed during the unloading process, the splicer must generally be operated in a darkroom. The darkroom is far from an ideal working environment so that the efficiency of the operating personnel is somewhat limited. Consequently, the capacity of such splicers is significantly lower than the capacity would be if the operators were permitted to work in a properly illuminated environment. 
     Recently &#34;daylight&#34; film splicers have entered the market which allow film to be loaded into a film splicer from a cassette in a properly illuminated environment. One such device is described in U.S. patent application Ser. No. 839,603, assigned to the assignee of this application. These recently developed daylight splicers are only semi-automatic so that they require relatively extensive manual manipulation of the cassette in order to load film into the splicer. The requirement of an operator for loading film into the splicer seriously reduces the throughput capacity of such splicers and introduces the possibility of error in film handling. 
     Another problem associated with conventional semi-automatic daylight splicers is their inability to adequately deal with film cassettes in which the film is incorrectly withdrawn from the cassette. Normally, as the backing strip is removed from the cassette thereby carrying the film from the cassette with it the backing strip protects the film from exposure to the daylight environment. However, a relatively small percentage of the cassettes which are unloaded become jammed so that the backing strip is removed from the cassette leaving the film behind. Another problem associated with an even smaller percentage of cassettes is that the film does not immediately exit the cassette but instead makes a complete loop within the cassette and exits the cassette backing strip so that the film is exposed to the daylight environment. The first above-mentioned problem is dealt with by segregating the cassette and subsequently processing it in a darkroom environment by conventional, non-automatic means. The second abovementioned problem is generally not dealt with in any satisfactory manner by conventional semi-automatic splicers so that a small percentage of film becomes inadvertently exposed. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to automatically unload film from a film cassette without operator manipulation other than to insert the cassette through an aperture. 
     It is still another object of the invention to automatically direct those cassettes from which film cannot be easily removed or from which the film has been incorrectly withdrawn without hazard of exposure to a particular location where they can receive special processing. 
     It is still another object of the invention to provide a film unloading mechanism having extremely high throughput capacity and which is incapable of inadvertently exposing film removed from the cassette. 
     These and other objects of the invention are accomplished by a mechanism which automatically unloads exposed film from a conventional film cassette at a high rate of speed and conveys the film to a light-free storage box is preparation for subsequent processing. The cassette is loaded into the mechanism through a shutter closable aperture and received by a cradle which places the leading edge of the film adjacent the inlet of an elongated film guide. A powered mechanism then engages a backing strip wound with the film which removes the backing strip from the cassette thereby carrying the film from the cassette into the film guide. The cassette and backing strip are then directed to respective disposal ducts. The leading edge of the film is guided past a light-free storage box by a pair of pivotally mounted guide doors until the leading edge has moved beyond the storage box and past a sensor at which time the guide doors pivot open thereby allowing the film to loop itself into the storage box. The operation of the film unloading and handling mechanism is controlled by a microprocessor and related electronic drive circuits so that it is capable of compensating for a variety of problems typically associated with removal of film from cassettes. Thus, the mechanism detects a condition whereby the film is jammed in the cassette and automatically rewinds the film back into the cassette and directs the cassette to a particular container for special handling. The mechanism is also able to detect when film is being incorrectly unloaded from the cassette in order to prevent inadvertent exposure of the film. 
    
    
     BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWINGS 
     FIG. 1 as an isometric view of a film splicer employing the inventive film unloading and handling mechanism. 
     FIG. 2 is an isometric view of the splicer illustrated in FIG. 1 with its side cover removed thereby showing its internal mechanism. 
     FIG. 3 is a side elevational view of the film unloading and handling mechanism. 
     FIG. 4 is a cross-sectional view taken along the line 4--4 of FIG. 3. 
     FIG. 5 is a side elevational view of the mechanism for directing processed cassettes to a first location for discard or to a second location for special handling. 
     FIG. 6 is a cross-sectional view of the film handling and unloading mechanism taken along the line 6--6 of FIG. 4. 
     FIG. 7 is a cross-sectional view of the cassette cradle and film guide inlet showing film being loaded into the film guide. 
     FIG. 8 is a side elevational view of the mechanism for rewinding film into the cassette in the event of an abnormal unloading situation. 
     FIG. 9 is a side elevational view of the film storage box and guide doors for selectively allowing film to enter the storage box. 
     FIG. 10 is a side elevational view of a frusto-conically shaped guide for directing backing strips from cassettes into a discharge chute. 
     FIG. 11 is an isometric view of the frusto-conically shaped guide of FIG. 10. 
     FIGS. 12A-12C comprise a flow chart of the program executed by an internal microprocessor for controlling the operation of the film unloading and handling mechanism. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A tape splicer employing the inventive film unloading and handling system is illustrated in FIG. 1. The splicer 10 includes an electrical section 12 and a mechanical section 14 mounted on a platform or table 16. A side panel of the electrical portion 12 includes a keyboard 18 for entering data and control commands into the system, and an alpha-numeric display 20 for outputing information and data. Conventional film cassettes having a pair of cylindrical film storage chambers spaced apart from each other by a rectangular film pad and an exposure number window are loaded into the mechanical portion 14 by placing the cassettes onto a chute 22 and allowing the cassettes to slide through a loading aperture 24. Thereafter, film is removed from the cassette and spliced to a previously unloaded length of film before being wound onto a takeup reel 26. 
     The internal features of the splicer 10 are illustrated in FIG. 2. The cassettes are initially received by the inventive film unloading and handling mechanism, 28 described in detail hereinafter, which places the film into an elongated film guide 30 and conveys the empty cassette and a backing strip wound with the film into a discharge receptacle 15 enclosed by the sidewalls of the platform 16. The ends of the film traveling through the film guide 30 are trimmed by a cutter 32 before its leading edge is fastened to the trailing edge of a previously unloaded length of film by a splicer 34. Finally, an identifying number is exposed onto the film by a projector 36 before the film is wound onto the takeup reel 26. Except for the features of the film unloading and handling mechanism 28, the remaining features of the splicer are described in detail in U.S. patent application Ser. No. 839,603 filed on Oct. 5, 1977 by John H. Siegel et al and assigned to the assignee of this application. 
     The film unloading and handling mechanism 28 is illustrated in further detail in FIGS. 3, 4 and 6. As explained above, a conventional film cassette C having a pair of cylindrical film containers F1, F2 connected to each other by a central portion A containing a film pad on which the film to be exposed rests and a rectangular exposure number window is initially placed on the chute 22. When the cassette C is released, it slides down the chute 22 through the loading aperture 24 onto a cassette cradle 38. Since the cradle 38 is inclined downwardly away from the chute 22 the cassette C moves along the cradle 38 until it contacts a discharge door 40 described in greater detail hereinafter. The loading aperture 24 is selectively closed by a shutter 42 which is moved between an open and closed position by a rotary actuator 44 through an arm 46. 
     The cassette cradle 38 is mounted on a vertically disposed podium 48 which, as illustrated in FIG. 7, houses an internal pneumatic ram 50. After the cassette has reached the position C&#39; illustrated in FIG. 6, pressurized air is directed to the ram 50 to place the cassette in the position C&#34; illustrated in FIG. 7 in which the film exit from the cassette is placed against an inlet 52 of the film guide 30. 
     After the cassette cradle 38 raises the cassette to the position C&#34;, an elongated violator probe 54 is quickly raised to an upper position through the exposure number window thereby removing a backing strip B wound with the film F from the cassette C and placing it between a pair of feed rollers 56, 58. As the violator plunger 54 removes a portion of the backing strip B from the cassette C, the film F is carried into the inlet 52 of the film guide 30. In normal operation, movement of the backing strip B to the rollers 56, 58 advances the film F a sufficient distance so that the leading edge of the film F extends beyond a first infrared light sensor 60 of conventional variety. The infrared light sensor 60 verifies that film F is being removed from the cassette C properly thereby indicating that normal operation of the mechanism should continue. 
     The violator probe 54 extends upwardly from a rack 62 which meshes with a pinion gear 64 driven by a conventional DC motor 66. It will be understood that the violator probe 54 may be actuated by other actuating devices either pneumatic or electrical. 
     After the violator probe 54 has placed the backing strip B between the feed rollers 56, 58 as illustrated in FIG. 7, the feed rollers 56, 58 are rotated thereby pulling the remaining length of backing strip B from the cassette C which in turn carries film F from the cassette C through the inlet 52 and into the film guide 30. The backing strip feed rollers 56, 58 each rotate with a gear 70, 72, respectively, and one of the gears 70 is connected through a shaft 74 to a sheave 76. The sheave 76 is driven by a conventional electric motor 78 through an output sheave 80 and flexible belt 82. 
     As the film F advances through the film guide 30, it is guided past a generally rectangular film storage box 84 by a pair of pivotally mounted guide doors 86, 88 each of which is moved between the closed position illustrated in FIG. 6 and an open position illutrated in FIG. 9 through a pair of pivotally interconnected links 90, 92 by a conventional rotary actuator 94 which may be a conventional rotary solenoid 94. When the leading edge of the film F reaches a second infrared sensor 95 positioned downstream of the storage box 84 the guide doors 86, 88 are opened thereby allowing the remaining film F to enter the storage box 84. The sensor 95 also actuates a film drive motor 97 (FIG. 6) to move the film F through the film guide 30. The ends of the film F can then be trimmed by the cutter 32 (FIG. 2) before it is spliced to the trailing edge of the previously loaded length of film by the splicer 34. The guide doors 86, 88 are closed at the start of a cycle as film F passes through the first light sensor 60. 
     The storage box 84 allows all of the film F to be unloaded from the cassette before the ends of the film are cut. In a relatively small percentage of cases, the film F jams in the cassette C. By insuring that the film has been removed from the cassette before its ends are trimmed, the film F can be rewound in the event of a film jam and placed in its original condition as explained hereinafter. Also, in an extremely small percentage of instances, the film F does not exit from the cylindrical film container F1 but instead winds around the opposite side of the backing strip so that withdrawal of the backing strip B carries the film F between the pull rollers 56, 58. Under these circumstances, the absence of film entering the film guide 30 is detected by the sensor 60 to prevent the pull rollers 56, 58 from rotating and to cause the film F to be rewound as explained hereinafter. 
     The backing strip B is removed from the film unloading and handling mechanism through a unique discharge guide which is best illustrated in FIGS. 4, 10 and 11. The backing strip pull rollers 56, 58 nest within a paper guide member 90 for guiding the backing strip B from the rollers 56, 58 to a downwardly extending discharge chute 92. The guide member 90 has a frusto-conically shaped guide surface forming a relatively narrow inlet and a relatively broad outlet. Cylindrically shaped cutouts 93 are formed in the guide member 90. The pull rollers 56, 58 thus guide the backing strip directly into frusto-conically shaped cavity and into the discharge chute 92. An air nozzle 94 positioned at the upper end of the discharge chute 92 directs an air jet downwardly to carry the backing strip B through the chute 92 into a discharge receptacle. 
     After all of the film F has been removed from the cassette C and the film has been spliced to the previously unloaded film the pressurized air is removed from the pneumatic ram 50 thereby allowing the cassette cradle 38 to lower to the position illustrated in FIG. 6. The discharge door 40 is then pivoted open by energizing a rotary actuator 98 (FIG. 3). The cassette C is then free to slide downwardly along the cassette cradle 38 into a discharge hopper 100 formed by a pair of upwardly diverging walls 102. The discharge hopper 100 opens into a cassette discharge chute 104 which carries the cassette to the discharge receptacle 15 (FIG. 2). 
     As mentioned above, in a relatively low percentage of instances it is necessary to rewind the film F into the cassette C. The mechanism for performing this function is best illustrated in FIG. 8. A rewind gear 100 driven by a conventional motor 102 is mounted on a frame 104 which is pivotally mounted for movement toward and away from the cassette C. During an unloading operation if either the first infrared sensor 60 the third downstream infrared sensor 95 (FIG. 9) or a second infrared sensor 103 (FIG. 6) does not detect the presence of film within a predetermined period, the frame 104 is pivoted toward the cassette C by a conventional rotary solenoid 106 through an actuating arm 108. The rewind gear 100 then meshes with a gear formed by a spool on which the film in the cassette is wound and the motor 102 is energized to rewind film into the cassette C. After a predetermined period, the solenoid 106 moves the rewind gear 100 out of engagement with the gear on the cassette, the discharge door 40 is opened and the casset cradle 38 is lowered as explained above. The cassette C is then discharged into the discharge chute 104. Since the cassette into which the film has been rewound must be specially processed, it is necessary to segregate these cassettes from the cassettes from which all of the film has been removed. For this purpose, a deflection mechanism illustrated in FIG. 5 is positioned at the outlet of the discharge chute 104. The deflection mechanism includes a deflection door 110 which is pivotally mounted for movement between two positions 110, 110&#39; one of which directs the cassette into a first discharge conduit 112 while the other of which 110&#39; directs the cassette into a second discharge conduit 114. The deflection door 110 is moved between its two positions by a conventional rotary actuator 116 such as a solenoid through a pair of pivotally interconnected lengths 118, 120. The first discharge conduit 112 leads to the discharge receptacle 15 while the second discharge conduit has an outlet 122 (FIG. 3) covered by a light-impermeable bag 124. Thus, film cassettes which must be specially handled such as those in which film has jammed in the cassette or the film has exited the cassette on the reverse side of the backing strip are directed to the bag 124 after all of the film has been rewound into the cassette. 
     In order to insure that the bag containing the cassette in need of special handling has been removed before subsequent cassettes are loaded into the splicer 10 a light sensor 126 is mounted adjacent the outlet 122 of the second discharge conduit 114. The light sensor 126 detects that the bag 124 has been removed from the outlet 122 and prevents further operation of the splicer 10 until the bag 124 has been repositioned over the outlet 122. 
     The operation of the entire splicer 10 including the film unloading and handling mechanism is controlled by a conventional microprocessor. Operation of the film unloading and handling mechanism can best be explained with reference to the flow chart (FIGS. 12A-12C) for the computer program executed by the microprocessor illustrated in FIG. 1. It will be understood, however, that the unloading and handling mechanism could be controlled by other types of conventional electrical devices. The loading is initiated by placing the cassette C on the inlet chute 22 and allowing the cassette C to pass through the loading aperture 24 onto the cassette cradle 38. In the first operational sequence, the shutter 42 is closed, the cassette cradle 38 is raised by actuating the pneumatic ram 50. After a 200 millisecond delay to provide sufficient time for the cassette C to be raised to the position C&#34; illustrated in FIG. 7, the violator probe 54 is raised by energizing the motor 66 thereby carrying the backing strip B between the backing strip pull rollers 56, 58. The first infrared sensor 60 is then checked to determine whether withdrawal of the backing strip B from the cassette C has resulted in film entering the inlet 52 of the film guide 30. If the leading edge of the film F has not passed beyond the infrared sensor 60 the program jumps to a rewind subroutine as explained hereinafter. If film has passed the sensor 60, the storage box guide doors 86, 88 are closed by the actuator 94, the backing strip feed rollers are rotated to remove the backing strip B from the cassette C and the air nozzle 94 in the backing strip discharge chute 92 is actuated to convey the backing strip to the discharge container. Removal of the backing strip B from the cassette C normally continues to unload film F from the cassette C. After 500 milliseconds, the leading edge of the film F should reach the second infrared sensor 95 which is positioned in the film guide 30 downstream from the storage box 84. If the leading edge of the film F has not reached this point within 500 milliseconds an error signal is generated and the system is shut-down. If, however, the leading edge of the film F has reached the second infrared sensor, the film drive motor 97 is energized and the storage box guide doors 86, 88 are opened by energizing the rotary actuators 94 to allow film to naturally curl into the storage box 84 as withdrawal of the backing strip B from the cassette C continues to carry film into the film guide 30. The third film sensor 103 is then checked to verify that the trailing end of the film F has passed in order to continue the processing cycle. If the film F has not passed the sensor 103 the system jumps to a rewind subroutine. The remaining portion of the splicer then trims the ends of the film and splices the leading end of the film to the trailing end of the previously unloaded film and winds the film onto the takeup reel 26. A flow chart and computer program for performing these functions, depicted in FIGS. 12A--12C, is contained in the aforementioned previously filed U.S. Patent application. 
     After the film F has been unloaded from the cassette and processed as explained above, the air nozzle 94 in the backing strip discharge chute 92 is de-energized and rotation of the discharge strip pull rollers 56, 58 terminates. The violator plunger 54 is then moved downwardly by energizing the motor 66 in reverse, air is removed from the pneumatic ram 50 to lower the cassette cradle 38 and the cassette discharge door 40 is opened by energizing the rotary actuator 98. After a delay sufficient to allow the cassette cradle to be lowered and the cassette C to slide downwardly into the hopper 100, the violator motor 66 is de-energized, the shutter 42 is opened and the cassette discharge door 40 is closed thereby terminating the unloading and handling cycle and allowing a new cassette to be unloaded into the splicer. 
     In the event that a rewind becomes necessary, the rewind subroutine initially terminates rotation of the backing strip pull rollers 56, 58, deactuates the air nozzle 94 in the backing strip discharge chute, opens the storage box guide doors 86, 88 and lowers the violator probe 54 by energizing the motor 66 in reverse. After a 30 millisecond delay, the rewind motor 102 is energized and the violator motor 66 de-energized. The infrared sensors are then checked to determine whether film is still present in the film guide 30. If the film is present the system is shut down pending investigation and possible repair. If the film has been removed from the film guide 30, the rewind subroutine continues. After a predetermined delay of a sufficient period to allow all of the film to be rewound into the cassette, the rewind motor 102 is de-energized, the solenoid 106 withdraws the rewind gear 100 from the cassette rewind gear, the cassette discharge door 40 is opened and the deflection door 110 is moved to the position 110&#39; (FIG. 5) to direct the cassette to the second discharge guide 114 into the special handling bag 124. The violator probe 54 is then lowered by energizing the motor 66 in reverse and air pressure is removed from the pneumatic plunger 50 in order to lower the cassette cradle 38. After a 150 millisecond delay, the violator motor 66 is de-energized, the cassette discharge door 40 is closed, the cassette deflector door 110 is returned to its original position and the shutter 42 is opened to allow a new cassette to be loaded through the loading aperture 24. 
     The inventive film unloading and handling mechanism is thus able to automatically remove film from a conventional cassette at a high rate of speed while compensating for unpredictable non-uniform characteristics of cassettes which prevent the film from being unloaded in a normal manner.