Patent GB-921927-A (GB)
Title: Improvements relating to photographic film assemblages
IPC: G03B17/34
Filed: 1961-02-09
Abstract: 921,927. Photographic film assemblages and cameras therefor. INTERNATIONAL POLAROID CORPORATION. Feb. 9, 1961 [Feb. 18, 1960], No. 4878/61. Class 98 (1). In a photographic film assemblage in which a container houses a photographic film unit having a photo-sensitive sheet mounted in position for exposure, a leader, for pulling the unit out of the container through an opening, and also a part which masks the photo-sensitive sheet to prevent its exposure and which extends from the interior of the container through the opening to provide a second leader for pulling the said part out of the container and unmasking the photosensitive sheet for exposure, the said part and the leader of the film unit are provided in the container with engagement portions which, on pulling the leader of the said part, are first moved into engagement and thereafter co-operate so that the leader of the film unit is moved out of the container. As shown (Fig. 4) the container of a film assemblage consists of a rigid box 10 comprising an exposure aperture 30 in one face, a bottom plate 14 which may be removed by sliding on guide flanges 22 but which is normally held in the position shown by co-operation of an end wall 18 with a flange 26 and detent projections 28 in said bottom plate and further comprising an opening 32 through which successive film units-including photosensitive and image-receiving sheets 40 and 42, a rupturable container 62 containing composition for effecting the diffusion transfer process, a leader sheet 50 and two connecting or carrier sheets 44 and 52-may be removed. The aperture 30 is normally masked by two cover sheets 82 which are connected to a leader 84 projecting out of the opening 32. Sequence of operation after a pack has been fitted, for example, to a camera in which the photosensitive sheets are to be sequentially exposed is as follows. The cover sheets 82 are first of all removed by pulling on leader 84. During the final movement of these sheets out of the container a recess 36 in a trailing section of one of the sheets 82 becomes engaged by an engagement portion 122 on the leader section 50 of the first film unit. By this means, said leader section 50 is brought through the opening 32 to a position whereat it may be manually grasped. This initial advancement of leader section 50 is accommodated without movement of other sheets by the provision of a Z-fold 134. The first photosensitive sheet 40 may now be exposed and subsequently removed (in superposition with an image-receiving sheet 42) by pulling on the leader section 50. In order that the leader of the next film unit (and similarly with each other film unit in turn) may be brought to a position where it can be manually grasped, a trailing section 142 is attached to the photosensitive sheet and is provided with a recess 144 for engagement by the engagement portion 122 of said leader of the next film unit. The engagement portion 122 (Figs. 6 and 7) may comprise any resilient flexible sheet material and have a triangular element 124 punched out on two sides and shaped as shown. An alternative shape for an engagement portion is shown in Fig. 9, comprising simply a bent strip of suitable sheet material. To prevent unintentional removal of the photosensitive sheets 40, perforated corner portions 154 of the trailer elements 138 are stapled to a housing member 74. The photosensitive sheets 40 are pressed flat into the exposure aperture 30, by the fact that a pressure plate 64, 66, 74, 76 is resiliently urged upwards (Fig. 4) by spring portions 80 (Fig. 2) cut out of the base plate 14. A camera suitable for use with the present film assemblage and similar to those disclosed in Specification 921,921 is shown in Fig. 11, said camera comprising a chamber 108 for accommodating the film assemblage, access to the chamber being by way of hinged rear door 102, and further comprising pressure rollers 114, 116 between which the film units are withdrawn, through opening 112. A spring 148 is provided in the camera which engages with the film units through a recess 146 in the base plate 14 and helps to ensure proper engagement between the respective engagement portions and recesses. In the event, however, of one of the leading sections 50 not being brought properly to a position where it may be manually grasped, the rear door 102 of the camera is provided with a hinged portion 118 in register with the recess 146 through which said leading section may be grasped for manual advance. A pair of hold-back springs 150 are provided in the camera in the region occupied by the opening 32 for preventing unintentional removal of sheets 42 as a result of friction arising from movement of other elements from the assemblage. Alternatively, this sheetrestraining means may be provided as a component of the film assemblage as described in Specification 921,921. An apertured spacing sheet 56 is provided for ensuring uniform spreading of the processing composition between the photosensitive sheets 40 and imagereceiving sheets 42 by the rollers 114, 116. Similarly, spacing elements attached to ends 54 of sheets 52 are provided for spacing the rollers apart in the region of the trailing ends to take up excess processing composition. Specifications 684,592 and 714,412 also are referred to.