Photographic Processing Apparatus

Abstract

Photographic processing apparatus having a film transport for serially, selectively, disposing a film of photographic negatives, or the like, upon an aperture that is in light transmitting alignment between a source of light and a printing device. A mounting frame includes a plurality of plate like members assembled to provide one or more adjacent apertures and a transverse slot that intercepts the apertures. A longitudinally elongated film, having indicia disposed thereon in predetermined relationship to areas containing a photographic image, is movably disposed in the slot. At least a pair of indicia responsive devices, such as photocells, are disposed in predetermined relationship with, and adjacent the apertures in the frame so that the image on the film will be disposed over the desired aperture when both of the indicia responsive devices indicate the presence of indicia on the film. A pair of film transporting devices in the form of resilient rubber rollers are disposed to engage the film in the slot on either side of the apertures and are driven in synchronism so as to serially, reversibly move the film past the apertures without exerting any substantive tensional or compressional forces longitudinally of the film to thereby avoid distortion and allow the film to lay flat in the area of the apertures. Motor control circuitry, including suitable logic is connected to the indicia sensing devices, a motor and brake, a source of power and a manual and/or automatic controller to control at least in part, the transporting of a film strip serially of the apertures with automatic or semi-automatic serial movement of the film strip with selective stopping in an aperture as directed. The motor-brake drive, or energizing, circuitry includes means responsive to a plurality of signals derived from the indicia on the film for initiating or stopping the transport of a film strip through the processing apparatus.

Description

BACKGROUND OF THE INVENTION

This invention relates generally to photographic printing apparatus and is more particularly directed to apparatus for rapidly, accurately positioning discreet sequential areas of a film strip in alignment with an aperture which in turn is disposed intermediate a source of light and suitable printing or image receiving or forming apparatus.

In known prior art apparatus, various and sundry arrangements are provided for placing a film having an image to be transferred to another medium, in a carrier, or the like, aligning the same with a source of light and a further holder for a photographic medium, such as printing paper, and then causing light to be transmitted through the film from the source of light on one side to the light responsive medium on the other side to thereby transfer the image on the same or a reduced or enlarged scale. Widespread use and acceptance of photography by the public has resulted in an ever increasing demand for faster, more accurate, efficient and versatile production of pictures and the like.

In practicing the principles of our invention, it has been determined that it is desirable to accumulate a quantity of films and combine the films in a serial sequential manner so as to provide an elongated strip of film containing a number of individual films which may be transferred from a supply reel to a take-up reel. Suitable photographic printing apparatus is then disposed intermediate the supply and take-up reels to sequentially and serially accept the film for the production of photographs under the control of a suitable operator.

The assignee of the present invention has been active in the development and production of apparatus of the general class with which our invention is concerned. Reference is made, in fact, to its commercially available devices known as PAKOTRONIC Printers, Models 75 and 77, for a full description of the general class of apparatus with which our invention is concerned.

In all of the known prior art apparatus, including those of the assignee of the present invention, the speed of operation has been relatively slow due to the unavailability of apparatus which could reasonably, satisfactorily position a film in alignment with an aperture for the subsequent printing operation. Hence, the operation has been performed, basically, under the manual supervision of a human operator using apparatus including various forms of hand operated or motorized take-up and supply reels where film strips of any substantial length may be utilized.

SUMMARY OF THE INVENTION

Briefly, our apparatus embodies a film positioning system which is operative to rapidly and accurately position a film strip containing appropriate indicia which are disposed in a predetermined pattern with respect to areas containing images to be transferred or printed. This is accomplished in a manner that exerts no tensional or compressional forces on a film as it is being transported so as to eliminate any undesirable effects that might be occasioned by differences in attitude of the film with respect to the plane of the aperture, and which readily accepts images at the beginning and end of a strip of film and which may further be utilized with strips of film of various size when suitably proportioned. Further, rapid, accurate and efficient motor control means are utilized in combination with indicia detecting means so as to provide the desired efficiency of operation.

It is therefore an object of our invention to provide an improved film handling apparatus for use in combination with photographic printing apparatus.

Another object of our invention is to provide an improved film handling apparatus that is operative at a faster rate.

A still further object of our invention is to provide a film handling apparatus which provides improved accuracy of positioning of film with respect to a desired predetermined location.

Another object of our invention is to provide an improved film handling apparatus having an increased efficiency of operation.

A still further object of our invention is to provide an improved film handling apparatus which is operative to trans-port film therethrough while exerting a minimum of tensional or compressional forces thereon.

Another object of our invention is to provide an improved indicia responsive motor control apparatus.

These and other objects of our invention will become apparent from a consideration of the appended specification, claims and drawings in which --

FIG. 1 is a diagrammatic view of the principal portions of a photographic printing apparatus or machine embodying the principles of our invention;

FIG. 2 is an enlarged isometric drawing of a portion of FIG. 1;

FIG. 3 is a top elevational view of the apparatus shown in FIG. 2;

FIG. 4 is a side sectional view of a portion of FIG. 1 taken along section line 4--4 of FIG. 3 of the drawing;

FIG. 5 is an enlarged top view of one embodiment of a control console which may be used to control the film transport apparatus embodying the principles of our invention when connected in the manner shown and described below;

FIG. 6 is a bottom view of a portion of a continuous film strip showing locations of images to be printed and indicia disposed in predetermined locations with respect thereto; and

FIG. 7 is an electrical schematic diagram of one preferred embodiment of the control circuitry for film transport apparatus shown in the other figures of the drawings.

Referring now to the drawings, in the overall apparatus shown in the partial fragmentary view on FIG. 1 of the drawings, a photographic printing apparatus is indicated generally by reference character 10. Printing apparatus 10 includes a desk-like base having a top work space 11 and vertical pedestal 12 mounted thereon. Pedestal 12 serves as a mounting for a printing paper magazine 13 and a cooperating downwardly extending lens assembly 14. A film transport apparatus is indicated generally by reference character 22 and is adapted to receive, transport and accurately position a strip of film 24 with respect to an aperture indicated generally by reference character 25.

Printing apparatus 10 also includes a control console 15 having a plurality of push buttons to be operated by a human operator and forms a portion of the control circuitry for film transport 22 in a manner to be described below. Printer apparatus 10 also includes take-up and supply reels 33 and 34, disposed on opposite sides of transport 22, for handling a continuous strip of film. While not shown in detail, film take-up and supply reels 33 and 34 may include suitable driving apparatus for feeding and removing film to and from film transport 22. This driving apparatus does not form a part of the present invention and hence is not described in substantial detail. SUCH APPARATUS IN THE GENERAL FORM JUST DESCRIBED OR which may occur to those skilled in the art may readily be obtained and utilized in the manner required to ensure a proper, uninterrupted and continuous supply of film , and removal of film, from the work space 11 and film transport apparatus 22.

Film Such apparatus in the general form just described or as having a means for providing a visual preview of a portion of film at a location adjacent to or in spaced relationship to lens assembly 14 so film, operator may view the film to be printed and make a final decision as to the exposure time to be applied to printer 10 so as to provide the necessary and desired quality of printing as the machine is operative to expose image receiving media in the form of paper in magazine 13 from a light source 31 disposed underneath work space 11. For this purpose, aperture 25 is divided into two serially spaced apart apertures, a preview aperture 30 and a printing aperture 32, each of a size corresponding to the size of the images 26, on film 24.

It may be apparent to those skilled in the art that many refinements and other features may be incorporated in the simplified form of printing apparatus indicated generally by reference character 10. For example, automatic exposure control apparatus may be incorporated along with focusing and other functions deemed desirable. It is likewise apparent that our invention may be operative under the uncomplicated conditions herein illustrated to satisfactorily perform its intended function.

Film transport 22 includes a base member 36, which is provided with previewing and printing apertures 30 and 32 respectively, and a top plate 29 which contains aperture 25 which is shown to encompass an area somewhat larger than that covered by apertures 30 and 32 in base plate 26. Suitable spacer members (not specifically identified) serve to define film receiving slots shown as left slot 37 and right slot 38, both in communication with the apertures in base 36 and top plate 29.

In FIG. 4 of the drawings, light source 31 is shown disposed above a suitable diffusing plate element (not identified) and a motor drive housing 35 is shown disposed rearwardly of apertures 30 and 32 and has film drive wheels 40 and 41 extending forwardly thereof and downwardly through suitable slots or apertures formed in top plate 29 so that the peripheries of drive wheels 40 and 41 may be in frictional driving engagement with a film, 24, extending through slots 37 and 38 in film transport 22. Directly underneath the axis of rotation of drive rollers 40 and 41 are a second pair of pinch rollers 42 and 43, each disposed on a suitable shaft, 44 and 45. The shafts are disposed in spring biased mountings which are biased upwardly toward drive rollers 40 and 41 to ensure frictional engagement with film 24 extending thereinbetween. Drive rollers 40 and 41 are mounted upon shaft members 47 and 46, respectively, which are in turn rotatably journaled in the front facing portion of housing 35. Suitable pulleys 50 and 51 on the rear ends of shaft members 46 and 47, are shown interconnected by a drive belt 48 which may preferably be of the cog type to ensure rotation of drive rollers 40 and 41 in unison. Shaft 46 is operatively connected to the shaft of a brake assembly 52 which is in turn connected, through suitable drive means, to the output shaft of drive motor 53. A housing 54, labeled "photo sensors," on FIG. 3 of the drawing, contains in control addition to light responsive elements such as photocells, a motor on drive circuitry which is further shown in schematic diagram on FIG. 7 of the drawing.

The apparatus housed in housing 54 includes three light responsive photo sensors 54A, 54B and 54C which are in operative light receiving relationship with the inner ends of a like plurality of flexible light conductive members 55A, 55B and 55C. The other ends of light conductor elements 55A, 55B and 55C extend into the top of a mounting therefor and are engagedly connected therewith and disposed over aperture 25 in plate member 29, according to a predetermined pattern corresponding to indicia present on film 24. The mounting may be adjustably disposed on top plate 29 to provide for initial adjustment of the apparatus.

Thus, it may be seen, that a continuous film strip 24, having indicia 27 and 28 disposed in predetermined relationship to images 26 to be transferred to another media as by projection, may be inserted at the left end of film transport 22 into slot 37. Energization of drive motor 53 and release of brake 52 serves to rotate drive rollers 40 and 41 and the film is engaged and transported to the right until such time as a signal is derived from the indicia on the film to suitably energize photo sensors A, B and C, in a manner to be described below, to stop the film with an image in aperture 30 for preview by the operator through viewing apparatus 23 (as shown on FIG. 1). Further serial transport of the film through film transport assembly 22 is effected by the control apparatus and the operator is supervising the overall operation of printing apparatus 10.

It may now be appreciated by those skilled in the art that the film transport apparatus includes a drive means which is operative to engage the film to be transported therethrough, on both sides of viewing and printing apertures provided in the apparatus so as to minimize and thereby substantially eliminate any effects due to differences in tensional or compressional forces that may be exerted on a film with other forms of motion producing apparatus.

Referring to FIG. 5 of the drawings, an operator's console 15 is shown to include a plurality of switches and push buttons, some of which are identified by reference characters 16, 17, 18 and 19 to provide functions which will be described below in connection with the operation of the schematic diagram of FIG. 7 of the drawings. The push buttons to which reference characters have not been applied are utilized by the operator to control the exposure time which in turn is governed by his subjective determination from observing the image on film 24 that is disposed over preview aperture 30. It is sufficient to say, that push buttons 16, 17 and 18 are normally open type of control switches which provide for reverse, repeat and forward drive to control the operation of film apparatus 22 and push button 19 is operative to initiate a printing cycle, the termination of which provides a signal to automatically cause film transport 22 to be operative to place the next successive image in proper position with respect to apertures 30 and 32.

Referring now to FIG. 7 of the drawings, a schematic diagram is shown as including a housing 54 in which, for purposes of simplicity, there is shown only some of the necessary elements which are preferably maintained shielded from ambient light for proper operation, although all of the circuitry, with the exception of motor 53 may be contained therein.

Light conductors 55A, 55B and 55C extend into housing 54, through suitable mounting apertures, into light transmitting relationship with photocells 54A, 54B and 54C respectively.

Photocells 54A, 54B and 54C are connected to amplifiers 56A, 56B and 56C respectively. The outputs of amplifiers 56A and 56C are connected to the input terminal of a switch 57, and amplifier 56B is connected to the input terminal of switch 58. Suitable diodes are provided in accordance with good engineering practice to maintain adequate separation of signals. The output terminals of each of normally open switches 57 and 58 are connected to a further output terminal 59 through suitable diodes and input terminals on normally open switches 57 and 58 are connected to a source of positive potential through conductor 60.

Output terminal 59 is connected to a conductor 75 that is in turn connected to an input terminal 73 on normally open switch 72 and to an input terminal 78 on normally closed switch 77 through diode 82 and resistor 83. Switch 72 is shown having an output terminal 74 connected to ground and is energized from a source of positive potential through conductor 71 and resistor 67. Normally closed switch 77 has an output terminal 81 connected to ground and is energized from a source of positive potential through conductor 71 and resistor 67. Normally closed switch 77 also has a further input terminal 79 connected to a source of positive potential through conductor 89 and resistor 90.

A one-shot multivibrator 166 is shown having a pair of terminals adapted to be connected to a source of potential for energization thereof, an input terminal 167 connected to conductor 99 and an output terminal 168 connected to input terminal 78 on normally closed switch 77 through conductor 85, diode 84 and resistor 83.

Brake means 52 is shown having an output shaft connected through driving means 150 to the shaft on motor 53. Brake means 52 is provide with a pair of terminals, one of which is connected to ground and the other of which is connected to an output terminal 69 on normally open switch means 68. Brake 52 is also shown connected to an output shaft (shown as driving means 46) that is in turn connected to pulley 50. Pulley 50 is operative to drive pulley 52 on shaft 47 through driving belt 48.

Normally open switch means 68 has an input terminal connected to terminal 66 on conductor 71 through conductor 65 and to input terminal 63 on normally open switch 62 through conductor 65 and conductor 64. Normally open switch means 68 includes a further terminal to be connected to a source of positive potential.

A normally open switch means 62 is shown having an input terminal 63 connected to conductor 64, conductor 65 and terminal 66 on conductor 71. Normally open switch 62 is also shown as energized from a source of positive potential through conductor 61 and conductor 60 and is provided with an output terminal that is further connected to terminal 129.

In the lower left-hand corner of FIG. 7, six transistors are shown connected in a symmetrical manner, three on each side of a centrally disposed motor 53 that is connected, through suitable driving means 150, to brake 52.

Motor 53 is shown having a pair of terminals for energization from transistors 104 and 108 respectively. Transistor 104 is shown having collector base and emitter electrodes 106, 107 and 105 respectively. Similarly, transistor 108 is symmetrically disposed and connected and includes collector base and emitter electrodes 110, 111 and 109. Emitter electrodes 105 and 109 are shown connected to conductor 103 which is in turn connected to terminal 129 and to the output terminal of switch 62 through conductor 128. The emitter and base electrodes of transistors 104 and 108 are interconnected by asymmetrical current conducting devices 130 and 131 respectively. The collector electrodes of transistors 104 and 108 are connected to ground through parallely connected capacitors and asymmetrical current conducting devices, the operation of which will be apparent to those skilled in the art and hence they have not been identified with specific reference characters.

Collector 110 on transistor 108 is shown connected to one input terminal on motor 53 through conductor 137 and is further connected to base electrode 107 on transistor 104 through asymmetrical current conducting device 135 and resistor 132. Collector electrode 106 on transistor 104 is connected to the other input terminal on motor 53 through conductor 136 and is further connected to base electrode 111 on transistor 108 through asymmetrical current conducting device 139 and resistor 133.

Similarly, transistors 112 and 116 are asymmetrically disposed with respect to one another. Transistor 112 includes an emitter, collector and base electrodes 113, 114 and 115 respectively and transistor 116 includes emitter, collector and base electrodes 117, 118 and 119 respectively. Emitter electrodes 113 and 117 are interconnected and further connected to ground through a conductor 145. Collector electrodes 114 and 118 on transistors 112 and 116 are connected to base electrodes 107 and 111 on transistors 104 and 108 respectively, through resistors 132 and 133 and to collector electrodes 106 and 110 through asymmetrical current conducting devices 139 and 135 respectively. Base electrodes 115 and 118 are connected to terminal 129 through resistor 141, resistor 139 and conductor 138; and resistor 142, resistor 140 and conductor 138, respectively.

A further pair of symmetrically disposed transistors 120 and 124 include emitter, collector and base electrodes 121, 122 and 123 and 125, 126 and 127 respectively. Collector electrode 122 is directly connected to terminal 151 intermediate resistors 141 and 139. Terminal 151 is also connected to base electrode 127 on transistor 124 through resistor 143. In a similar manner, collector electrode 126 on transistor 124 is connected to terminal 152 disposed intermediate resistors 140 and 142. Terminal 152 is also connected to base electrode 123 on transistor 120 through resistor 144. Emitter electrodes 121 and 125 are connected to conductor 145 and thence to ground.

Base electrode 123 is shown connected to reverse switch 16 through conductor 146, asymmetrical current conducting device 148, conductor 100 and cable 20. Base electrode 127 on transistor 124 is connected to switch forward 18 through conductor 147, asymmetrical current conducting device 149, conductor 97, conductor 96, conductor 94 and cable 20. Switch 18 is also connected to a source of signal through capacitor 95. It may also be noted that conductor 97 is also connected to input terminal 167 on multivibrator 166 through asymmetrical current conducting device 98 and conductor 99 and conductor 100 is connected to input terminal 167 through conductor 101, asymmetrical current conducting device 102 and conductor 99.

Normally open switch 17 may be operative to connect conductor 89 to ground through conductor 92 and terminal 93.

OPERATION

In considering the operation of the illustrated embodiment, it is preferable to first consider the operation of the various switches which have been defined above.

Switch 57 is a normally closed switching element which, upon energization of its input terminal is operative to provide a positive going output at its output terminal from the source of positive potential connected to conductor 60.

Switch 58 exhibits the same characteristics and is therefore further described as a normally closed switch which provides a positive going output at its output terminal.

Switch 72 may be considered as a normally open switch in that its input terminal connected to terminal 66 must be energized with a positive potential to render the path intermediate terminal 73 and output terminal 74 conductive.

Switch 77 is provided with a pair of input terminals 78 and 79, both of which must be simultaneously energized to close or complete a conductive path intermediate terminals 80 and 81 hence, it exhibits the characteristics of a normally open switch that is closed upon concurrence of signals at least a pair of input terminals.

Switch 68 is a normally open type of switch which, upon energization of the input terminal connected to conductor 65 and terminal 66, renders conductive a path intermediate a source of positive potential connected to a terminal thereon and an output terminal 69 to energize the device connected to conductor 70.

Switch 62 is a like normally open type of switch in that an input terminal 63 connected to terminal 66 through conductors 64 and 65 requires the presence of a positive potential to render conductive the current path extending through the other two terminals of the switch from conductor 61 to conductor 128 connected to terminal 129.

Assuming the overall apparatus is in the middle of a strip of film 24 contained in the slot extending through film transport 22, and that the film is stopped so that the apparatus may be in the process of printing an image from the film contained in aperture 32. The transport is inoperative, awaiting the initiation of an automatic signal signifying that the printing step has been completed, or a manual signal from the operator. Such a signal may be generated by the application of a negative going pulse to capacitor 95 or by momentarily closing forward switch 18, both of which serve to apply a negative going pulse to conductor 94. The film is caused to advance one frame, or unit, and when this has been accomplished, film transport 22 is de-energized while a printing cycle may take place.

Should it be desirable to reverse the operation of the film transport, this may be done a frame at a time by closing, momentarily, switch 16 to thereby create a negative going pulse on conductor 100.

A further provision is made for disabling the transport by the closure of switch 17 which serves to prevent operation of the transport in either direction while allowing repetition or repeating of a printing function.

Going back to the starting point assumed above the film transport is stopped, the point in sequency of operation is prior to the end of a printing operation. The printing operation accomplished independently of the transport apparatus but does provide for a signal in the form of a negative going pulse to capacitor 95 at the time the apparatus has finished making a print of the frame of the film then in aperture 32. Keeping in mind the functions of switches 57, 58, 73, 77, 68 and 62 as outlined above, at this stage of operation switches 57 and 58 are closed to supply a positive potential to conductor 76 and to input terminal 78 on switch 77. A positive potential exists at input terminal 79 on switch 77. Switch 73 is open and switch 77 is closed because of the concurrence of a positive signal at input terminals 78 and 79. Because of the lack of potential at terminal 66 due to the fact that output terminals 80 and 81 are conductive to form a path to ground from resistor 67, switches 62, 68 and 72 are open.

Upon receipt of a pulse from the printing apparatus to capacitor 95 or upon momentary closure of switch 18, monostable multivibrator 166 is rendered operative to supply a negative going pulse to terminal 78 on switch 77 to cause it to open the conductive path intermediate output terminals 80 and 81. This causes the potential to rise to a positive value at terminal 66 to close switch 72 and thereby ground conductor 76 and to close switches 62 and 68 to energize brake 52 and motor 53 to allow the start of operation of the film transport. During this time, since the sensors connected to switches 57 and 58 may still sense the indicia disposed on the film strip, switches 57 and 58 remain operative to supply a positive output to conductor 76. However, because switch 72 is closed, this output is ineffective to render switch 77 conductive.

After the single pulse of predetermined energy content supplied by monostable multivibrator 166 has terminated, the operation is continuous with switches 57 and 58 open, switch 72 closed, switch 77 open and switches 62 and 68 closed.

At the time the indicia sensors are in alignment with the indicia on the exemplary film, switch 57 is closed with an input from sensor 54A or 54C and switch 58 is closed with an input from sensor 54B. The closing of switches 57 and 58 serves to apply a positive potential to conductor 76 which is sufficient to cause input terminal 78 on switch 77 to be energized with a positive potential which, with the continued concurrent application of the positive potential at input terminal 79, renders switch 77 conductive intermediate its output terminals 80 and 81 which in turn reduces the potential at terminal 66 to essentially ground potential to thereby cause de-energization of switches 72, 68 and 62, and de-energization of which causes de-energization of brake 52 and motor 53 and the film transport terminates its operation with the next frame of the film in the desired position with respect to aperture 25 and apertures 30 and 32.

It should be noted that the disposition of the indicia sensors, as may be seen on FIG. 2, with respect to the indicia 27 and 28 disposed on the film strip, provides for operation of the apparatus whereby the beginning of a film strip may be sensed and cause proper operation of the apparatus by sensors 54A and 55B whereas the end of a film strip may likewise cause the desirable operation of the apparatus through the use of sensors 54B and 54C.

While the basic operation of the apparatus has been described above in connection with the operation of the various sources of signal and signal responsive means, it may be seen that the manner in which motor 53 is energized is also unique in its application of the various elements of which it is comprised.

When switch 62 is rendered conductive, a positive potential is applied to conductor 103 through terminal 129 and conductor 128. Simultaneously a positive potential is applied through conductor 138 to resistors 139 and 140 and thence through resistors 143 and 144 to base electrodes 123 and 127 on transistors 120 and 124. Base electrodes on transistors 120 and 124 are also connected to conductors 97 and 101 respectively. At the time of the receipt of a negative going pulse "End of Print signal" or upon the momentary closing of switch 18, a current path exists from base electrode 127 on transistor 124 to ground terminal 93, or its equivalent, to allow current to flow from positive terminal 129 through resistor 139 and resistor 143. This provides a potential to base electrode 115 on transistor 112 to render it conductive and will also render transistor 124 conductive so that terminal 152 intermediate resistors 140 and 144 will assume essentially a ground potential and thereby prevent energization of transistors 120 and 116.

The conduction of transistor 112 provides for energization of motor 53 in a direction corresponding to the output from transistor 104 which is rendered conductive and current will flow from terminal 129, through transistor 104, through conductor 136, motor 53, conductor 137, asymmetrical current conducting device 135, transistor 112 and conductor 145 connected to ground. Simultaneously, transistor 108 may be rendered conductive and may conduct from terminal 129 through conductor 103, transistor 108, asymmetrical current conducting device 135, transistor 112 and conductor 145 to ground. However, any conduction that may occur will be ineffective insofar as motor 53 is concerned and motor 53 will be operative in a direction to drive the film transport in a forward direction with respect to the overall apparatus.

When it is desired to reverse the operation of the apparatus, switch 16 is momentarily closed thereby providing a current path from conductor 101 to ground terminal 93 to allow conduction of current from terminal 129 through resistor 140, resistor 144 to conductor 101 through conductor 146 and asymmetrical current conducting device 148. This has the effect of rendering transistor 116 conductive and also rendering transistor 120 conductive to place terminal 151 at essentially a ground potential to prevent energization and conduction of transistors 112 and 124. Current may then flow from terminal 129 through transistor 108, conductor 137, motor 53, conductor 136, asymmetrical current conducting device 139, transistor 116 and conductor 145 to ground. In a manner similar to that described above, transistor 104 may be rendered conductive but its current will flow from terminal 129, through transistor 104, asymmetrical current conducting device 139, transistor 116 and conductor 145 connected to ground.

In view of the functional description of the various switching elements described above, it may also be desirable to view our apparatus from the standpoint of the various signals that may be present and which are combined to interact to provide the desired function of the apparatus. This may be most easily accomplished by considering the output of the means for sensing the indicia on the film or web of material that is being transported and positioned as a first source of signal which indicates the absence or presence of the predetermined, desired pattern of indicia which will serve to appropriately position the film. Then, through the use of a signal responsive means that is connected to the indicia sensing means so as to respond to the first source of signal, a second source of signal is added which, when combined with the first source of signal will result in a third signal which is used to control the first signal and to effect operation of further signal responsive means which are operative, upon receipt of a signal to start or stop the operation of the actual material driving means. Other sources of signal might be appropriately utilized to provide further functions of the apparatus, such as a fourth source of signal which would require the signal responsive means connected to the indicia sensing means to be operative, in one sense, only upon concurrence of the first and fourth signals in the same sense, or polarity. It may be recognized that the first signal is the output of the photocell indicia sensors, the second signal is the output of the one shot multivibrator (or equivalent), the third signal is the output of switch 77 and the fourth signal is the signal appearing at input terminal 79 on switch 77.

Claims

We claim:

1. Apparatus of the class above described, comprising in combination:

a. a base member having an aperture and including a longitudinal slot extending therethrough and intersecting with said aperture, said slot being adapted to slidably receive and support a strip of material;

b. a strip of material to be positioned within said base member and predetermined relationship with said aperture, said strip of material including indicia serially disposed at predetermined locations thereon;

c. drive means, disposed adjacent said aperture in frictional driving relationship with said strip of material in said slot, said drive means including motor means and braking means therefor;

d. a plurality of indicia sensing means disposed adjacent said aperture, each of said sensing means being responsive to the presence of an indicia to provide an output indicative of the presence of an indicia on said strip of material; and

e. control means, including power supply means therefor connected intermediate said plurality of sensing means and said motor and brake means, and including first and second pluralities of current controlling means, each of said pluralities of current controlling means including circuit means for alternately applying current in one direction or another to reversibly energize said motor means, said first and second pluralities of current controlling means including means for rendering one conductive while maintaining the other non-conductive in response to a source of signal of a reversible plurality, said control means being operative in response to a concurrence of output signals from at least two of said plurality of sensing means to actuate said brake means and de-energize said motor means.

2. The apparatus of claim 1 in which the first and second pluralities of currents controlling means are symmetrically disposed.

3. The apparatus of claim 1 in which each of the pluralities of current controlling means includes at least a pair of current controlling devices connected in series with a motor means.