Light-tight package

Abstract: An improved light-tight package for a roll of a length of web material such as photographic paper or film. The package includes an opaque leader wound around the roll. Folded-over portions of opaque tearable flexible end disks are held in place by adhesive tape strips. A rigid disk is positioned intermediate the end disks and the end surfaces of the roll. In a preferred embodiment, the adhesive tape is tearable and the leader includes a portion adapted to initiate a tear in the tearable tape and the end disks. Upon unrolling of the package by pulling the leader, the tape tears, and the end disks tear circumferentially, so that the folded-over portions adhere to the leader when the leader separates from the roll, and the rigid disks provide support for the flexible end disks.

Description: The invention relates to packages for rolls of web material. More particularly, the invention relates to a light-tight package suitable for use with sensitized goods such as rolls of photographic paper and film. Rolls of light sensitive paper and film require light-tight packaging so that such rolls are not exposed to white or room light so that the light sensitive characteristics of the rolls would be damaged. While such packaging must be light-tight, such packaging needs to facilitate the loading of the rolls in room light into cooperating apparatus which dispense or otherwise use the paper or film. Further, once positioned within the cooperating apparatus, the packaging must not adversely affect the ease of rotation of the roll during unwinding, and must not interfere with the roll if the web is re-wound back onto the roll. US-A-4,148,395, commonly assigned, discloses a package which includes a pair of flexible opaque end disks or covers attached to the ends of a core of the roll, and an opaque leader attached to a leading end of the length of paper or film forming the roll. A peripheral portion on each end disk is folded over and adhered to an edge of an underlying convolution of the leader. A layer of adhesive is provided on the underside of the peripheral portion prior to folding over. When the leader is pulled away from the packaged roll, the end disks tear circumferentially at the edge of the roll; so that, the peripheral portion remains adhered to the leader. However, since the folded over portions tend to crimp or fold unevenly, passages for light tend to be formed between the folded over portions and the leader, which can allow light to reach and damage the paper or film. US-A-5,133,171, commonly assigned, discloses a package which includes a pair of similar end disks and a leader. After a first convolution of the leader is wrapped on the roll, peripheral portions of the end disks are folded over the first convolution. A second convolution is then wrapped onto the roll to capture the folded-over peripheral portions between the first and second convolutions and to make the package light tight. Friction is relied upon to retain the folded-over portions between the convolutions of leader and no adhesive is used. However, the frictional engagement between the folded-over portions and the convolutions of the leader occasionally is not sufficient to prevent the folded-over portions from slipping at least partially free, thereby permitting entry of light and damage to the product. The requirement for a second full convolution also adds expense to the product and produces additional waste material for the customer. Research Disclosure No. 22932 of May 1993 shows a package in which the end disks have the same diameter as the roll. A strip of adhesive tape is wrapped around each of the circumferential edges of an outer convolution of the leader and then folded over onto the end disk. The folded over portions of the tape strips tend to crimp or fold unevenly, so that passages for light tend to be formed between the folded over portions and the end disks, which can allow light to reach and damage the paper or film. Extra components, such as an enclosing bag, may be necessary to ensure light tightness. US-A-5,353,933 discloses a package in which a light-shielding leader with covers is connected to the end of a photosensitive strip of material. The leader is wound twice around the roll, and the side edges of the covers are inserted into the core and fixed by the insertion of a bushing into the core with pressure. A notch is formed in the covers to ensure and facilitate opening at the forward end of the covers. When the leader is drawn, a pulling force acts on the notch, and the covers are torn along adhesion outside boundaries. Once torn, the covers extend or fan outwards from the core, which may adversely affect the ease of rotation when unwinding the web material from the core, resulting in image disturbance if an image is applied during unwinding. In addition, the extended covers may fold over if the web is re-wound back onto the roll, causing. scratching of the photosensitive material. Further, providing notches in the covers results in an extra manufacturing step, and may tend to form light passages. Canadian Patent Application No. 2,124,969 discloses a package wherein the end face of the roll is covered by a cover element including an opaque flexible sealing disk, a flexible section, and a hub-shaped section. The flexible sealing disk curves over the outer edge of the end face's circumferential surface to create a light-proof closure and prevents contamination of the film by adhesive. Once positioned within a cooperating apparatus, the flexible sealing disk and flexible section may fold over if the web is re-wound back into the roll, thereby scratching or damaging the web. The objective of the present invention is to provide an improved light-tight package which remains properly closed until opened during room light loading. Another object of the present invention is to provide such a package the elements of which do not interfere with dispensing of the product after opening of the package. Still another object of the present invention is to provide such a package which will allow for rewinding of the roll onto the core once loaded within the cooperating apparatus without damage to the product. A further object of the present invention is to provide such a package in which no adhesive remains near the roll after opening of the package, thereby preventing contamination of the edges of the product of the cooperating apparatus with adhesive. Yet another object of the present invention is to provide such a package in which, once loaded in the cooperating apparatus, the remaining packaging does not interfere with the operation of the roll within the cooperating apparatus. Still another object of the present invention is to provide such a package which will not interfere with the use of the product, particularly when an image is applied to the product as the product is being unwound from the roll. These objects are given only by way of illustrative examples; thus, other desirable objectives and advantages inherently achieved by the disclosed invention may occur or become apparent to those skilled in the art. The scope of the invention is defined by the appended claims. According to one aspect of the invention, there is provided a light-tight package comprising a core having opposite ends and a length of light-sensitive web material wound about the core to form a roll. The roll includes end surfaces at the opposite ends of the core and an outer diameter. The web material has a leading end and a length having a first width. A flexible opaque leader is attached to the leading end of the web material and wound about the roll through at least a first convolution. The leader has a second width which is substantially equal to the first width, a length greater than a circumference of the roll, and opposite lateral edges separated by the second width. The package also includes a pair of flexible opaque end disks and a pair of rigid disks. The rigid disks are positioned intermediate the end disks and the end surfaces. Each of the rigid disks has an outer diameter less than or equal to the outer diameter of the roll, and the end disks cover the end surfaces. A central portion of each flexible end disk is attached to the core and a peripheral portion of each flexible end disk is folded over a circumferential edge of the leader. At least one strip of adhesive tape adheres to the outer surface of the folded over portion and to the outer surface of the leader for at least one convolution. In a preferred embodiment of the invention, there is provided a light-tight package comprising a core having opposite ends and a length of light-sensitive web material wound about the core to form a roll. A flexible opaque leader is wound about the roll through at least a first convolution. The leader includes a first and second portion, with the first portion having a width substantially equal to the width of the web, and a length greater than a circumference of the roll. The leader is attached to a leading end of the web material. A pair of flexible opaque end disks cover the end surfaces, and a pair of rigid disks are positioned intermediate the end disks and the end surfaces. The rigid disks have an outer diameter less than or equal to the outer diameter of the roll. A central portion of each end disk is attached to the core and a peripheral portion of each end disk is folded over a circumferential edge of the first portion of the leader. An edge of at least one strip of tearable adhesive tape is positioned along the circumferential edge of the folded over portion. The strip adheres to the outer surface of the folded over portion, and to the outer surface of the first portion for at least one convolution. The second portion of the leader is adapted to initiate a tear in the tearable adhesive tape so as to tear the end disks along the circumferential edge of the folded over portion, so that the folded over portion separates from the end disk and remains adhered to the leader. The package according to the present invention provides important advantages over prior art packages. The use of adhesive strips ensures that the end disks will remain securely attached to the leader to provide a light tight package before the package is opened. When a roll wrapped in accordance with the invention is placed in a cooperating apparatus, the strip of leader is removed to open the package, so that the adhesive strips remain with the leader, and no opportunity is provided for contamination of the product by adhesive. Once the leader is removed, the end disks do not interfere with the cooperating apparatus, thereby allowing the roll to fit compactly within the cooperating apparatus. The rigid disks, positioned intermediate the flexible end disks and end surfaces of the roll, allow rewinding of the roll onto the core within the cooperating apparatus, and prevent the flexible end disks from contacting or damaging the product. A much shorter leader is needed than with prior art packages since a second, full convolution of leader is not required for light tightness. In a preferred embodiment, the structure of the leader is adapted to initiate a tear in the tearable tape. The foregoing and other objects, features, and advantages of the invention will be apparent from the following more particular description of the preferred embodiments of the invention, as illustrated in the accompanying drawings. FIG. 1 illustrates schematically a perspective, exploded view of a roll of web material with a leader attached to the leading edge of the web material, a pair of unattached rigid disks, and a pair of unattached end disks. FIG. 2 illustrates a perspective view of the package of the present invention as it is assembled. FIG. 3 illustrates a perspective view of an assembled package of the present invention. FIG. 4 illustrates a perspective view of a package of the present invention as it is torn from the roll. FIG. 5 shows several arrangements of leaders for the present invention. The following is a detailed description of the preferred embodiments of the invention, reference being made to the drawings in which the same reference numerals identify the same elements of structure in each of the several figures. Figures 1 through 4 show a roll 10 of light-sensitive web material, such as photographic paper or film. The roll 10 includes a central, typically flangeless, hollow core 12 having opposite ends and a length approximately equal to the width of a length 14 of such web material. Length 14 is wound onto core 12 such that the wound roll 10 has opposite end surfaces 16,18. A leading end 20 of length 14 is joined to a flexible, opaque leader 22. Leader 22 includes a trailing end 24, and a width approximately equal to the width of length 14 of web material. To prevent inadvertent exposure of the product, the length of leader 22 is at least as long as one circumference of roll 10. Extra length may be included for grasping leader 22 by the customer. Leader 22 may be made of various opaque materials, for example, polyester containing carbon black or rubber-modified high density polyethylene containing carbon black. A suitable carbon black content would be in the range of 3 to 8 percent by weight. A thickness of leader 22 would be in the range of 0.076 to 0.381 mm, preferably 0.127 to 0.254 mm, which provides suitable tensile strength. Adhesion means 26, such as a strip of tape, may be used to join ends 20 and 24. Other adhesion means 26 to attach ends 20,24 may include ultrasonic or heat splicing. Leader 22 has longitudinally extended lateral edges 28,30 and a centerline 29. As illustrated in Figure 1, leader 22 includes two ends, a first portion 31 having trailing end 24, and a second portion 33. First portion 31 is at one end of leader 22, while second portion 33 is at the other end of leader 22. The width of first portion 31 is substantially equal to the width of length 14, and the length of first portion 31 is greater than one times the maximum circumference of roll 10. Second portion 33 includes at least one feature adapted to initiate a tear in a tearable adhesive tape. Such a feature is, for example, a taper extending inwardly toward centerline 29. As illustrated in Figure 1, such a taper may form an angle theta () with respect to lateral edge 28 or 30, with angle  ranging between 0 and 90 degrees, preferably 30 to.45 degrees. Alternatively, as illustrated in Figure 2, leader 22 may include a third portion 35, arranged such that second portion 33 is intermediate first portion 31 and third portion 35. In such an embodiment, third portion 35 would have a width less than the width of first portion 31. Referring to Figures 1 through 4, a pair of flexible, light-impervious, opaque end disks 32,34 are provided to cover end surfaces 16,18. Each disk 32,34 includes a central portion 36 with a hole 38 approximately smaller in diameter than an internal diameter of core 12. End disks 32,34 are made of an opaque but thin and flexible material which has a reduced tensile strength to permit circumferential tearing of end disks 32,34 when the assembled package is opened. Optionally, end disks 32,34 may include a plurality of radial cuts or slits 40 extending radially outward from hole 38 through the thickness of end disks 32,34 to facilitate attachment of end disks 32,34 to core 12. The portions of the disks between cuts 40 would be folded into core 12 and secured to core 12, for example, by adhesive, heat sealing, or other means of bonding. A peripheral portion 42 of each end disk 32,34 extends somewhat beyond the radius of roll 10, between 5 and 16 mm, preferably 8 mm, to allow for variation in the diameter of roll 10. In the assembled package, peripheral portions 42 are folded over the circumferential edges of the first convolution of leader 22 onto the outer surface of leader 22, as illustrated in Figures 2 and 3. End disks may be made of an opaque but thin and flexible material which has a reduced tensile strength to permit circumferential tearing of end disks 32,34 when the assembled package is opened. The material may be flimsy and may have no shape-memory characteristic. A suitable material which permits tearing is a paper, foil, polyethylene laminate. Other suitable materials for end disks 32,34 include any suitable polyolefine based film, plastic film, or lamination which could include high density polyethylene, polypropylene, cellophane, polyester, and various combinations thereof, which are opaque, flimsy, and have a tensile strength which permits tearing during use in the package according to the present invention. A pair of rigid disks 41,43 are positioned intermediate end surfaces 16,18 and end disks 32,34, respectively, so that the end disks are outboard the rigid disks. Rigid disks 41,43 includes a central portion 45 with a hole 47 approximately equal to or larger in diameter than the internal diameter of core 12, and an outer diameter equal to or smaller than the diameter of roll 10. Rigid disks 41,43 are made of a rigid material sufficient to support end disks 32,34, and separate the flexible end disks and the end surfaces. That is, the rigid disks provide a support for the end disks such that the end disks, after the assembled package is open, do not interfere with the end surfaces. Through this structure, the end disks remain upright, preferably parallel to end surfaces 16,18 of roll 10. The end disks, because of their flexibility, have the potential of being trapped between laps of the web on roll 10 during unwinding and rewinding. Once the package is opened, by supporting the flexible end disks in such an orientation, the end disks will not fold-over or come into contact with web 14 during unwinding and rewinding of roll 10. Folded-over end disks could cause jams in the cooperating apparatus, leading to lost productivity, labor expenses, or costly replacement components. Thus, independent of the material characteristics of the end disks, the rigid disks will provide support for the end disks. Suitable materials for rigid disks 41,43 are paper, polyester, polystyrene, high impact polystyrene, polypropylene, polycarbonate, polyvinylidene chloride, and acetate. Depending on the material selection, a suitable material thickness is in the range of about 0.0004 inches (0.01mm) to about 0.015 inches (0.4mm). Such materials need not be opaque, and may be used in combination with others, and combined through co-extrusion or by a lamination process. In a preferred embodiment, the rigid disks are made of an acetate with a thickness of approximately 0.010 inches (0.254mm). Rigid disks 41,43 need not be attached to core 12. For example, rigid disks 41,43 can be positioned within the package by being tightly held between end disks 32,34 and end surfaces 16,18, respectively. The portions of end disks 32,34 between cuts 40 can assist in tightly holding rigid disks 41,43 between end disks 32,34. Alternatively, rigid disks 41,43 can be attached to end disks 32,34, respectively, such as with an adhesive, heat sealing, or other means of bonding. Similarly, rigid disks 41,43 can be attached to core 12, for example, by providing rigid disks 41,43 with an appropriately sized inner diameter and radial cuts as illustrated in Figure 1 with regard to end disks 32,34. Peripheral portions 42 of end disks 32,34 are folded over onto the first convolution of leader 22 to form folded-over portions 48,50. Elongated strips 44,46 of adhesive tape secure folded-over portions 48,50 to leader 22. Strips 44,46 are wrapped around the outer surface of folded-over portions 48,50 and the outer surface of marginal portions 52,54 (shown in Figure 1) of at least a first convolution of leader 22. Preferably, strips 44,46 extend over folded-over portions 48,50 to locations not beyond the lateral edge 28,30 of leader 22. Described alternatively, each folded over portion 48,50 has a circumferential edge, and strips 44,46 extend over folded-over portions 48,50 to locations not axially beyond the circumferential edge. Adhesive strips 44,46 extend along leader 22 for a distance appropriate to provide at least one full convolution around roll 10, though more than one convolution can be provided. While continuous strips of adhesive tape 44,46 are preferred, those skilled in the art will appreciate that several shorter overlapping, abutted, or intermittent lengths could be used without departing from the present invention, so long as any spacing between the shorter lengths does not permit entry of light. Further, particularly for rolls 10 having narrow widths, a single strip of adhesive tape may be used for both folded-over portions, rather than one strip for each folded-over portion. In addition, while the use of two strips is preferred, only one strip may be utilized, so long as there is no entry of light. Adhesive strips 44,46 should be opaque and have a transverse width greater than the width of folded-over portions 48,50. Preferably, strips 44,46 have a transverse width of about twice the width of folded-over portions 48,50, with about half of this width being adhered to the folded-over portions and half to leader 22. Adhesive strips 44,46 preferably have the property of adhering well to leader 22 and to folded-over portions 48,50. In addition, strips 44,46 must have the characteristic of being tearable. Those skilled in the art will appreciate that any adhesive tape having these characteristics will be suitable. An example of such a suitable adhesive tape is Product No. 235, an opaque tape made by 3M Company, or Product No. 53137, an opaque tape made by Tesa Company. To assemble the package according to the present invention, length 14 is wound onto core 12. Rigid disks 341,43 are attached to end disks 32,43. Preferably after winding, end disks 32,34 are then attached to core 12 at central portion 36. Trailing end 24 of leader 22 is attached to lead end 20 of length 14. Leader 22 is wound around roll 10. Then. peripheral portions 42 are folded over onto leader 22, more particularly first portion 31, to form fold-over portions 48,50, as best illustrated in Figure 3. As shown in Figures 3 and 4, folded-over portions further extend over all or a segment of second portion 33. The folding over may be done manually, or using any convenient apparatus. Strips 44,46 are then fed from suitable spools 60,62 and wrapped around the package. taking care to cover folded-over portions 48,50. Optionally, lead end 64 of leader 22 may be secured to roll 10 by any convenient manner, such as by means of tape strip 66, to provide a completed assembled light-tight package according to the present invention. When the assembled package is opened in a cassette or cooperating apparatus, tape 66 is unsecured, and leader 22 is pulled away from roll 10. Typically, core 12 is supported by means (not illustrated) which engage core 12 and permit the assembled package to rotate as leader 22 is removed. In a cassette, leader 22 would be threaded through an exit slot which forms a light barrier and the cassette would enclose roll 10. Since strips 44,46 are made from a material which permits tearing, a pull on leader 22 eventually subjects second portion 33 to a force so that the feature of second portion 33 initiates a tear in strips 44,46. The strength of leader 22 is such that the tear propagates along the feature of second portion 33 to the lateral edges 28,30 of first portion 31. End disks 32,34 are made from a material which permits tearing, and the tearing force is less than the force needed to un-adhere folded-over portions 48,50 from leader 22. Accordingly, strips 44,46 adhere to folded-over portions 48,50, and end disks 32,34 tear along the circumferential edge of folded-over portions 48,50 and tear free from the remainder of the end disks. As illustrated in Figure 4, when leader 22 has been completely pulled away from roll 10, folded-over portions 48,50 remain adhered to leader 22, and would exit the cassette with the leader. The operator can then remove tape strip 26, discard the leader, and thread leading end 20 of length 14 into the cooperating apparatus. During operation within the cooperating apparatus, flexible end disks 32,34 are prevented from folding over onto web 14 by rigid disks 41,43. In the embodiment illustrated in Figure 2, third portion 35 would have a width less than the width of first portion 31. More particularly, the width of third portion 35 would be approximately the width of first portion 31 minus at least two times the width of adhesive strips 44,46. Third portion 35 can be used to thread leader 22 through an exit slot in a cassette or cooperating apparatus, and provide grasping means for pulling away leader 22 from roll 10. Figure 5 illustrates other embodiments of the feature of second portion 33 adapted to initiate a tear in a tearable adhesive tape. Figure 5(a) shows a convex curvature, while Figure 5(b) shows a concave curvature. Other features which provide tearing of both the end disk and adhesive tape may be known to those skilled in the art. Figures 5(c) through 5(h) show configurations wherein third portion 35 has a width approximately equal to first portion 31. In using the configuration of Figures 5(c) through 5(h), adhesive strips 44,46 would be wrapped around first portion 31, while holding third portion 35 apart so as to not wrap adhesive strips around third portion 35; thus leaving third portion 35 free from adhesive strips 44,46. As will be understood by those skilled in the art, rigid disks 41,43 can be incorporated within other light-tight packaging using flexible end disks, and are not restricted to the packaging configuration of the particular embodiment described.

Claims: A light-tight package comprising: a core (12) having opposite ends; a length (14) of light-sensitive web material wound about the core to form a roll (10), the roll having end surfaces (16,18) at the opposite ends of the core and an outer diameter, the web material having a leading end and a length having a first width; a flexible opaque leader (22) attached to the leading end of the web material and wound about the roll through at least a first convolution, the leader having a second width substantially equal to the first width, a length greater than a circumference of the roll, and opposite lateral edges separated by the second width; a pair of rigid disks (41,43) having an outer diameter less than or equal to the outer diameter of the roll; a pair of flexible opaque end disks (32, 34) covering the end surfaces, the rigid disks positioned intermediate the end disks and the end surfaces, a central portion of each flexible end disk being attached to the core and a peripheral portion of each flexible end disk being folded over a circumferential edge of the leader, each folded over portion (48,50) having an outer surface and a circumferential edge; and at least one strip of adhesive tape (44 or 46) having an edge, the strip adhering to the outer surface of the folded over portion and to the outer surface of the leader for at least one convolution. The light-tight package as claimed in claim 1 wherein the flexible end disks comprise a material of sufficient tensile strength to allow tearing before the at least one strip of adhesive tape releases the folded over portions, such that the end disks tearing circumferentially and the folded over portions separate from the flexible end disk and adheres to the leader. A light-tight package as claimed in claim 1, further comprising: the leader having a first (31) and second (33) portion, the second portion (33) adapted to initiate a tear in the tearable adhesive tape so as to tear the end disk along the circumferential edge of the folded over portion, so that the folded over portion separates from the flexible end disk and adheres to the leader. The light-tight package as claimed in claim 3 wherein the second portion (33) includes a feature of a taper extending inwardly toward a centerline of the leader which initiates the tear in the tearable adhesive tape. The light-tight package as claimed in claim 4 wherein the taper of the second portion (33) extends inwardly by an angle greater than zero degrees and less than or equal to 90 degrees. A light-tight package as claimed in claim 1, further comprising: the leader having a first (31), second (33) and third (35) portion, the second portion disposed intermediate of the first and third portion, the first portion having (i) an outer surface, (ii) a second width substantially equal to the first width, and (iii) a length greater than a circumference of the roll, the third portion having a third width less than the second width of the first portion; the strip adhering to the outer surface of the first portion for at least one convolution, the second portion adapted to initiate a tear in the tearable adhesive tape so as to tear the end disks along the circumferential edge of the folded over portion, so that the folded over portion separates from the end disk and remains adhered to the leader. The light-tight package as claimed in claim 6 wherein the second portion includes two side walls and a feature of a taper extending inwardly toward a centerline of the leader from at least one side wall which initiates the tear in the tearable adhesive tape. The light-tight package as claimed in claim 7 wherein the taper of the second portion extends inwardly by an angle greater than zero degrees and less than or equal to 90 degrees. A light-tight package as claimed in claim I, further comprising: the leader having a first (31), second (33) and third (35) portion, the second portion disposed intermediate of the first and third portion, the first portion having (i) an outer surface, (ii) a second width substantially equal to the first width, and (iii) a length greater than a circumference of the roll, the third portion having an outer surface and a third width substantially equal to the second width of the first portion; the strip adhering to the outer surface of the first portion for at least one convolution while not adhering to the outer surface of the third portion, the second portion adapted to initiate a tear in the tearable adhesive tape so as to tear the end disks along the circumferential edge of the folded over portion, so that the folded over portion separates from the end disk and remains adhered to the leader.

Inventors: KAUSCH THOMAS J, KENNEDY KEVIN T, MALONE ARTHUR N, KAUSCH, THOMAS J., KENNEDY, KEVIN T., MALONE, ARTHUR N.
Applicants: EASTMAN KODAK CO, EASTMAN KODAK COMPANY
Application year: 1996
Main classification: G03C3
IPC codes: G03C3, B65D85