METHOD OF MANUFACTURING A FILM UNIT

The present invention relates to a method for the manufacture of a circular film unit for use with cameras.

U.S. Patent 4,212,673, issued July 15, 1980 discloses a film unit comprising a circular film disk having metering notches around its periphery and a core in a central opening. The borders of image areas of the disk are preexposed.

Accurate alignment of the metering notches and the core with the borders is critical to accurate location of the image areas in a camera. In U.S. 4,212,673, this problem is not dealt with directly, but the disk, notches and central opening are cut and borders are exposed prior to insertion of the core.

Handling of loose film disks in a continuous process is undesirable for several reasons, including the risk of damage to the image area. It is the object of the invention to provide a method of manufacture of a film unit of the type described, which method provides accurate alignment between such preexposed borders and metering notches in a continuous, high production run process without the risk of damage to the image area associated with handling of loose film disks.

This object is accomplished by a method which includes advancing a web of unexposed photographic material along a path and, first, exposing image area borders in an annular locus on said web and cutting the web to form a plurality of perforations along a circular locus and a central opening inside the circular locus, both openings and perforations being accurately spaced relative to the image area borders; second, mounting the core in the central opening; and third, severing the web along

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the locus of the perforations to remove a film unit from the web, with the perforations forming the metering notches.

By inserting the core prior to severing the disk, handling ease of the disk and care of the image areas are improved. By exposing the borders and cutting the perforations prior to mounting of the core, accurate alignment between the image areas and the notches can be maintained more precisely than would be the case if the perforations were cut in a later operation, for example, with the final severing step.

In the detailed description of the preferred embodiment of the invention presented below, reference is made to the accompanying drawings in which:

Fig. 1 is a perspective view of a film unit to be manufactured in accordance with the invention;

Fig. 2 is a sectional view of the film unit of Fig. 1;

Fig. 3 is a schematic view of a portion of an apparatus for carrying out the present invention; Figs. 4-7 are detailed views of portions of the apparatus shown in Fig. 3; In the drawings, several features have been shown in schematic form. These and many other features for use therewith are well known, and the present description is directed in particular to elements forming part of or cooperating more directly with manufacturing and assembling apparatus.

Apparatus that is not specifically shown or described herein is understood to be selectable from apparatus known in the art or from apparatus which will readily occur to those having ordinary skill in the art to which the present application is directed.

Referring to Figs. 1 and 2, a film unit 1

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according to the prior art includes a film disk 2 mounted on a central core 4 and attached to the core by a sonically welded ring 6. Film unit 1 has a plurality of metering notches 24 located on the periphery of film disc 2 and a plurality of image areas 28 which are defined by exposed (but undeveloped) borders and located annularly around the disk.

Fig. 3 shows a series of operations on a web of light sensitive film during the manufacture of film units such as shown in Fig. 1.

A roll 10 of photographic film stock 12 is supplied to the film unit manufacturing apparatus. The film stock end is threaded through a tension looper roll 14 and a servomotor driven vacuum pacer drum 16. At the other end of the film path shown in Fig. 3, a set of servomotor driven pinch rollers 18 and 20 interact with pacer drum 16 to position the film web along its path. A work station 22 is provided to cut perforations 27 along a circular locas as well as an opening 26 (Fig. 4) in the center of the locus of perforations 27 to receive core 4. A work station 64 is provided to expose the borders. Work station 64 is shown prior to work station 22, but workstations

64 and 22 could be reversed or combined into one work station. The important thing is that the border exposing and the perforation cutting operations be conducted physically close to each other to increase the accuracy of the location of the final notches and the exposed borders. At work station 22, a single punch assembly is lowered to cut a plurality of perforations 27 and opening 26 for the core 4. Perforations 27 will be used to form notches 24 during a later operation. By cutting perforations 27 prior to insertion of the core, accuracy of location

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between the perforations and the image areas can be maintained more precisely than if the notches were cut in an operation later in the process, for example, if the notches were formed while severing the entire film disk.

Referring once more to Figs. 1 and 2, central core 4 is held to film disc 2 by a ring 6 ultrasonically bonded to the core. This portion of the assembly operation is performed at a work station 34 shown generally in Fig. 3 and in more detail in Figs. 5 and 6. Referring to Fig. 5, a plurality of rings 6 are supplied from a vibratory bowl, not shown, and are conveyed as a train of parts into a supply track to be picked up and held by vacuum in the tip of an ultrasonic horn assembly 36.

A plurality of cores 4 are supplied by a vibratory bowl also and are conveyed as a train into line with ultrasonic horn assembly 36 and its anvil assembly 38. The anvil assembly is raised by a crank arm 40, and the ultrasonic horn assembly is lowered by a similar crank arm 42 to insert a core 4 into punched central opening 26 in web 12, lower a ring ,6 into contact with the core, and ultrasonically seal the ring to the core. This operation is schematically illustrated in Fig. 6.

A work station 44, shown in Figs. 3 and 7, includes a crank-driven die set operated by an hydraulic cylinder, not shown, which turns shaft 46 below film web 12 to raise and lower a punch. The punch, which is round, cooperates with a round die 48 to separate the finished film unit from web 12 along the locus of previously punched perforations 27. The accuracy of this operation is not as critical as the arcuate location of the perforations with respect to the image areas. However, it has been found that if the same basic mechanism is used to control alignment

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at work stations 64, 22 and 44, the relative location of notches 24 and picture areas 28 is more precise if perforations 27 are cut at work stations 22 than if they are cut at work station 44. For example, alignment for all these stations may be controlled by reference holes cut in the web at or upstream of the first of these stations. For more details of such an alignment mechanism, see Research Disclosre, No. 20228, page 95, published February 1981 by Industrial Opportunities Ltd. of the United Kingdom.

After the film discs are punched from the web, the web passes over an idler roller 50, through pinch rollers 18 and 20 and into a waste bin, not shown. As the film units are punched from web 12, they are picked up by one of a plurality of rotatable vacuum heads 52 which are extendably mounted on a transfer rotor 54. From this point, further handling of the film unit is by contacting the core. The vacuum heads transport the film units to cleaning apparatus and assembly machinery for completion of photographic film cartridges.

By the above-described invention, alignment of notches 24 with image areas 28 is assured because the notches 24 (perforations 27) are punched out in an operation physically close to the operation of exposing the borders.

Similarly, if the central opening 26, notches 24 and perimeter of the disk were to be cut at the same time, the disk would be severed from the web prior to insertion of the core. Each disk would then have to be individually handled greatly increasing risk of damage to the image areas and the complexity of the handling equipment.