Radiation proof tamper-indicating container

The invention relates to a tamper-indicating radiation-proof film container. The container comprises a canister having an opening defined therein, and a closure member having a peripheral canister-engaging portion. A tamper-indicating seal is located between adjacent contact surfaces of the canister-engaging portion and the canister, and the closure member is translucent for enabling the condition of the tamper-indicating seal to be viewed. Shielding means are provided for shielding the contents of the container from ionising radiation. The shielding means may be in the form of an intermediate lead layer and an inner barium-impregnated plastics layer which lines both the canister and the closure member. The tamper-indicating seal incorporates indicia containing information relating to the contents of the container. The primary advantage of the film container of the invention is that it allows photographic film to be sold with the purchaser safe in the knowledge that the film has neither been tampered with, nor damaged by X-radiation. The suitably protected photographic film also does not need to be removed from luggage which is to be X-rayed.

BACKGROUND OF THE INVENTION 
This invention relates to a radiation-proof tamper-indicating film 
container. 
Nowadays, most 35 mm photographic film is sold and stored in transparent 
canisters. This has the advantage that, once the cardboard box comprising 
the outer packaging of the film has been removed, essential information 
about the type of film contained within the canister can still be obtained 
without opening the canister. Furthermore, in many parts of the world, 
unscrupulous dealers sell, as new film, either (at best) old stock, or (at 
worst) film cassettes containing only the film leader strip which suggests 
a full roll of film where none, in fact, exists. 
A transparent canister therefore enables the user to establish instantly 
the type of film contained therein, as well as the essential photographic 
information relating thereto. Furthermore, it enables the buyer to make at 
least a superficial examination of the film cassette in order to establish 
whether it has been tampered with or not. 
The major short-coming of a transparent film canister is that it increase 
the possibility of damage to the film due to inadvertent exposure to a 
light source. Furthermore, a transparent container provides little or no 
protection from the other forms of radiation to which photographic film 
may be exposed. A prime example of this is the possible exposure of 
photographic film to X-radiation during baggage checks at airport 
terminals. 
The potential for damage to both developed and undeveloped photographic 
film subjected to X-radiation is an established fact. For travellers whose 
baggage is subject to X-ray security screening, it represents at least 
four areas of concern. 
Firstly, there is a possibility that the "film-safe" X-ray machines used to 
examine hand luggage are incorrectly calibrated or maintained, resulting 
in higher-than-recommended levels of X-radiation. 
Secondly, as increasingly mentioned in most leading photographic texts, and 
as proved in extensive research by the American Society of Magazine 
Photographers, X-radiation is cumulative in its effect on photographic 
film. One or two exposures of film to X-ray screening in a "film-safe" 
device may well have no deleterious effect. However, for the traveller 
moving through a number of such X-ray checks, cumulative exposures may 
well damage film. 
Thirdly, as instanced by the same authority, the higher the ISO rating of 
film (the "faster" the film is) the greater is its sensitivity to 
X-radiation. A "film-safe" X-ray machine calibrated not to damage 
conventionally rated films in the ISO 25-400 range offers no assurance of 
X-ray protection to the ultra-fast films of around ISO 800-2000 used by 
professionals today. 
Finally, there exists the possibility of conventional, as opposed to 
"fail-safe" X-ray screening machines, being used on luggage committed to 
the hold of an aircraft. 
While many airports issue warnings to remove all photographic film from 
luggage prior to it being X-rayed, others do not. Many travellers or 
professional photographers forget to do so and their photographic films 
may consequently get damaged. 
SUMMARY OF THE INVENTION 
According to the invention there is provided a tamper-indicating container 
comprising: 
a) a canister having an opening defined therein; 
b) a closure member having a peripheral canister-engaging portion; 
c) a tamper-indicating seal located between adjacent contact surfaces of 
the canister-engaging portion and the canister, at least part of the 
closure member being translucent for viewing the condition of the 
tamper-indicating seal; 
d) shielding means for shielding the contents of the container from 
ionising radiation. 
In a preferred form of the invention, the tamper-indicating seal 
incorporates indicia containing information relating to the contents of 
the container. 
Conveniently, the canister-engaging portion has a depending 
outer-peripheral translucent skirt which incorporates the window. 
In one form of the invention, the tamper-indicating seal may comprise a 
frangible strip laminated between adjacent contact surfaces of the 
canister-engaging portion of the closure member and the canister. 
The frangible strip may be in the form of a printed strip of foil or film 
bonded by means of adhesive layers both to an inner contact surface of the 
canister-engaging portion of the closure member and to an outer contact 
surface of a lip forming part of the canister. 
In one form of the invention, the strip of foil or film may be embedded 
within a thermoplastic resin. 
In an alternative form of the invention, the indicia may comprise indents 
formed in at least one of the adjacent contact surfaces of the 
canister-engaging portion and the canister, the indents being filled with 
a coloured ink material, and a bonding agent being interposed between the 
ink material and the opposed contact surface, whereby removal of the 
closure member from the canister causes at least some of the ink material 
which is bonded to the bonding agent to be lifted away from the indents so 
as to indicate tampering. 
The closure member may have an outer layer formed from a translucent 
plastics material and an inner layer formed from the shielding means, the 
shielding means terminating before the tamper-indicating seal. 
In a preferred form of the invention, the shielding means is in the form of 
a layer of lead which lines and forms an inner layer for both the canister 
and the closure member, thereby forming a complete surround for shielding 
the contents of the container. 
The shielding means preferably includes a layer of material which contains 
barium. 
More preferably, the shielding means is constituted by an intermediate 
layer of lead bonded to an inner layer of a barium-impregnated plastics 
material. 
The walls of the container are conveniently constituted by the intermediate 
layer of lead laminated between the inner layer of barium-impregnated 
plastics material and outer layer of a relatively rigid plastics material. 
The container is advantageously in the form of a round-cylindrical canister 
and a circular closure member, the container being sized to house 
complementally a single roll of photographic film. 
The canister may be provided with an outer peripheral lip adjacent the 
opening thereof, and the canister-engaging formation may comprise an inner 
wall and an elastically deformable outer wall defining in combination a 
substantially U-shaped channel complemental with the lip, the outer wall 
having a re-entrant portion formed towards the free end thereof behind 
which the peripheral lip is adapted to engage in a snap fit, the contact 
surfaces being located on the outer surface of the outer peripheral lip 
and the inner surface of the outer wall. 
The shielding means preferably extends to the upper edge of the lip of the 
canister extends along the outer surface of the inner wall of the 
canister-engaging formation, thereby providing a double radiation-proof 
seal. 
The lip may have a wedge-shaped profile which narrows towards the opening, 
and the U-shaped channel may have a complemental wedge-shaped cavity for 
accommodating the lip. 
The re-entrant portion advantageously has an inwardly slanting face against 
which the outer surface of the wedge-shaped lip initially bears on 
insertion of the closure member, so as to splay open the elastically 
deformable outer wall prior to the lip locating in a snap fit within the 
wedge-shaped cavity.

DESCRIPTION OF EMBODIMENTS 
The tamper-indicating 35 mm film container 10 illustrated in FIGS. 1, 2 and 
4 includes a closure member or cap 12 engaged in a snap fit with a 
canister 14. The cap 12 is moulded from a translucent plastics material, 
and has an outer-peripheral canister-engaging portion 16 through which 
printed indicia 18 can be viewed. The printed indicia 18 may display 
written information relating to the type of film (PROFILM ABC), the number 
of exposures (36), the film speed (400), and the temperature below which 
the film should be stored (27.degree. C.). Further information relating to 
the photographic film, including the expiry or "exposed by" date and other 
characteristics of the film may also form part of the printed indicia 18. 
The printed indicia 18 are printed on and may form part of a 
tamper-indicating seal, which will presently be described in more detail 
with reference to FIGS. 3, 3A and 3B. As can be seen in FIG. 2, once the 
cap 12 has been removed from the canister 14, the tamper-indicating seal 
is destroyed, together with the indicia printed thereon, as is shown at 
20. 
Referring now to FIGS. 3 to 6, the cap 12 has an outer peripheral skirt, or 
outer wall section 24. The canister 14 has an upper lip or wall 26 which 
forms a snap-fit within a U-shaped channel 27 defined between the skirt 24 
and an inner wall section 28 of the cap 12. The skirt 24 defines an 
outside wall which telescopes over an inside wall defined by the lip 26, 
when the cap is installed. A tamper-indicating seal 30 is laminated 
between those inside and outside walls, i.e., between the outer surface 32 
of the lip 26 and the inner surface 34 of the skirt 24. The 
tamper-indicating seal comprises a strip of metallic foil 36 which is 
bonded to both the outer surface 32 of the lip 26 and the inner surface 34 
of the skirt 24 by means of respective layers of adhesive 38 and 40. The 
indicia 18 are printed on the upper surface 42 of the foil 36. The bonding 
co-efficient of the layers of adhesive 38 and 40 to the respective outer 
and inner surfaces 32 and 34 and to the foil 36 is such that the foil 36 
and the indicia 18 printed thereon constitute the weakest zone of fracture 
between the outer surface 32 of the lip 26 and the inner surface 34 of the 
skirt 24. As a result, if the film container 10 is opened by removal of 
the cap 12, the foil 36 and the indicia 18 are damaged, as can be seen at 
20, thereby providing a clear indication that the film container has been 
tampered with. 
Referring now to FIG. 3B, an alternative tamper-indicating seal 44 is shown 
in which the indicia 18 are in the form of indentations 45 moulded into 
the outer surface 32 of the lip 26. A suitable layer of paint or ink 46 is 
then applied to fill the moulded indentations 45 in order to make the 
indicia stand out more prominently. A layer of adhesive 48 is provided 
between the outer and inner surfaces of the respective lip 26 and skirt 
24. The adhesive has a co-efficient of adhesion to the ink or paint 46 
which is less than the co-efficient of adhesion between the ink or paint 
36 and the outer layer 32 of the lip. As a result, once the cap 12 is 
removed it carries with it at least a portion of the indicia, thereby 
resulting in both the indicia and the tamper-indicating seal being 
damaged, the damaged indicia being clearly viewable through the skirt 24, 
as can be seen at 20. 
Both the outer walls 50 and 52 of the respective canister 14 and cap 12 are 
formed from a translucent semi-rigid polyester material. The outer wall 50 
of the canister 14 may alternatively be formed from an opaque material, 
such as polyester treated with a black pigment. An intermediate layer of 
lead shielding 54 and 56 is laminated between the respective outer walls 
50 and 52 and respective inner layers 58 and 60 of the canister and the 
cap. The inner layers 58 and 60 are formed from a barium-impregnated 
polyethylene material. The outer walls 50 and 52 have a thickness of 
approximately 1 mm, while the lead shielding has a thickness of 0.2 mm, 
and the barium-impregnated polyethylene layer is 0.3 mm thick. The lead 
shielding 54 and 56 and the barium-impregnated polyethylene inner layers 
58 and 60 provide, in conjunction, both light and X-ray shielding means to 
ensure that the photographic film housed within the container 10 is not 
damaged when passing through X-ray machinery at airport baggage checks, or 
the like. To this end, both the layers of lead shielding 54 and 56 and the 
inner layers of barium-impregnated polyethylene 58 and 60 completely line 
the side walls and base of the canister 14 and cap 12 respectively. 
Referring now to FIGS. 5 and 6, the barium-impregnated polyethylene layer 
60 terminates at the entrance to the channel 27 and the lead shield 56 has 
an exposed portion 56A which lines the outer surface of the inner wall 28 
and a further exposed portion 56B which lines the base of the channel 27. 
The skirt 24 has a re-entrant portion 62 having an inwardly slanting front 
face 64, terminating in a curved recess 66 which merges with an inwardly 
slanting rear face 68. As can be seen more clearly in FIG. 3, the curved 
recess 66 forms a complemental fit with a curved shoulder 69 defining the 
base of the wedge-shaped lip 26. The lip 26 has an outer wedged surface 70 
tapering inwardly towards the upper edge 72 of the canister 14. The wedged 
surface 70 forms a snug complemental fit with the inwardly slanting face 
68, which defines one side of a wedge-shaped cavity 73. When the cap 12 is 
press-fitted onto the canister 14, the wedged surface 70 initially abuts 
the inwardly slanting face 64, thereby splaying the deformable semi-rigid 
skirt 24 away from the inner wall 28 and opening the channel 27 until the 
shoulder 69 snaps into position behind the recess 66. 
As can be seen in FIG. 6, an exposed portion 74 of the lead shield 56 is 
urged against the exposed area 56B of lead shield at the base of the 
channel 27 when the lid is snapped into position. The barium-impregnated 
polyethylene layer 58 simultaneously abuts the portion of lead shield 56A 
lining the inner wall 28. The double shield at the interface of the 
canister 14 and the lid 12, constituted by the lead shield 56A, the 
barium-impregnated polyethylene layer 58 and the lead shield 54, ensures 
that there is no zone of weakness at the interface between the lid and the 
canister which is either X-ray or light pervious. 
In an alternative embodiment of the invention, the cap may be formed from 
an opaque plastics material, with a translucent window being provided in 
the lip thereof for viewing the tamper-indicating seal. This embodiment 
has a possible disadvantage in that a more complicated manufacturing 
process is required in order to provide a cap having a separate window. 
The tamper-indicating seal is not confined to the specific seals described 
in the embodiments, but may be in the form of any tamper-indicating seal 
interposed between the canister-engaging portion of the cap 12 and the 
canister 14. For instance, a stress-opacifying seal may be provided. 
Alternatively, the strip of foil or film may be embedded within a 
thermoplastic resin. 
Furthermore, the indicia 18 need not necessarily form part of the 
tamper-indicating seal, but may be printed, moulded or embossed separately 
on the outer surface of the lip of the container or on the inner surface 
of the cap. The remainder of the outer surface 70 of the lip may be 
coloured differently, to the tamper-indicating seal, thereby serving to 
indicate clearly through the skirt when the cap has been removed and has 
been replaced with the tamper-indicating seal out of alignment. As can be 
seen clearly in FIG. 3, even though the cap 12, and possibly the canister 
14 is translucent, the previously-referred-to double shield does not 
permit light or ionising radiation to pass completely through the walls of 
the container to the photographic film contained therein. 
The tamper-indicating container of the invention is not necessarily 
confined to a film container, but may extend to any other container having 
contents which are radiation-sensitive, and which are liable to be 
tampered with. 
The primary advantage of the film container of the invention is that it 
allows photographic film, especially high quality film, to be sold 
over-the-counter in the container of the invention, with the purchaser 
safe in the knowledge that the film has neither been tampered with, nor 
damaged by X-radiation. The need to remove the suitably protected 
photographic film from luggage which is to be X-rayed, or to house it in a 
separate X-ray-proof pouch, is also precluded. 
It is foreseen that the film container of the invention will be of 
particular use to both serious amateur and professional photographers. The 
relatively minor additional costs of a container of this type are 
outweighed by its benefits; degradation of expensive unused film and 
damage to potentially valuable exposures is effectively avoided using this 
film container. The tamper-indicating seal also serves to indicate 
automatically to the photographer after having used several rolls of film, 
those canisters which house unexposed film and those canisters which house 
exposed film, without the need to mark the canisters individually or to 
open them.