BACKGROUND OF THE INVENTION
Field of the invention.
[0001] The present invention relates to a lighttightly packaged roll of light-sensitive
strip material wound on a hollow supporting core, and more in particular to such roll
which is intended for daylight loading of a dispenser magazine which, after its loading,
can be placed in a suitable exposure apparatus, e.g. a phototypesetter or a COM (computer
output microfilm) system.
Description of the prior art.
[0002] Lighttightly packaged rolls of light-sensitive strip material wound on a hollow supporting
core are known, which comprise a lighttight flexible end cover for each end surface
of the roll, each end cover having a central opening and being lighttightly attached
to a corresponding end of the core, a lighttight flexible circumferential cover secured
to the coiled strip material and covering the outermost convolution of the roll. Corresponding
ends of end covers and circumferential cover are lighttightly fitted to each other
so as to obtain a lighttight and/or moisture-tight wrapping. Examples of this kind
of wrapping are disclosed in US-A 4 148 395 and 4 505 387. An improved roll packaging
which overcomes problems with dimensional tolerances of the roll of wound strip material
is disclosed in US-A 4 733 777.
[0003] The latter roll package comprises a lighttight flexible end cover for each end surface
of the roll, each end cover having a diameter in excess of the diameter of the roll
of wound material, and a lighttight flexible circumferential cover having a width
in excess of the width of the strip material. The inside faces of the rims of the
circumferential cover are sealed to the corresponding inside faces of the rims of
the end covers extending beyond the perimeter of the roll of wound strip material.
[0004] A roll package as described is supported between two rigid flanges having a hub engaging
the corresponding core opening, and the roll thus supported is packed in a rectangular
cardboard box for storage and shipping. Contact of the flanges with the sealed rims
of the wrapping material locates said rims in parallel planes, normal to the axis
of the roll. Since the flanges have a diameter, or circumscribe a diameter if they
are rectangular, which is larger than the diameter of the rims in their normal planes,
there is no contact between the edges of the rims and the adjacent walls of the packaging
box.
In view of today's environmental considerations, the flanges, which usually are made
of a hard plastic such as polystyrene or polyvinyl chloride, are considered as an
undesirable load.
[0005] We have found that omission of the mentioned flanges from the packing box is detrimental
to the quality of the sealed rims of the wrapping material. As a matter of fact, repeated
moving contact between the outer edges of said rims and the adjacent walls of the
box during transport and/or other manipulations of the boxes causes uncontrolled compression
and alternating bending of the rims whereby their lighttight sealing can get destroyed.
SUMMARY OF THE INVENTION
Object of the invention.
[0006] It is an object of the present invention to provide a roll package of light-sensitive
strip material wound on a core and lighttightly wrapped in a wrapper having rims of
a circumferential cover and of end covers sealed at their inside to each other, which
readily lends itself to be packaged in a cardboard packing box without the use of
rigid flanges for supporting such roll in such box.
Statement of the invention.
[0007] In accordance with the present invention, a lighttightly packaged roll of light-sensitive
strip material wound on a hollow supporting core, which comprises a lighttight flexible
end cover for each end surface of the roll, each end cover having a central opening
and being lighttightly attached to a corresponding end of the core and each end cover
further having a diameter in excess of the diameter of the roll of wound material,
and a lighttight flexible circumferential cover secured to the coiled strip material
and covering the outermost convolution thereof, said circumferential cover having
a width in excess of the width of the strip material, the inside faces of the rims
of the circumferential cover being fitted to the corresponding inside faces of the
rims of the end covers extending beyond the perimeter of the roll of wound strip material,
is characterized thereby that the fitted rims of the lighttight wrapping thus formed
have a bending all along their circumference towards the outer surface of said wrapping.
[0008] The bending of the fitted rims of the lighttight wrapping can occur either towards
the circumferential portion of the wrapping or to the corresponding end covers thereof.
In both cases the rims have a form such that any contact with a corresponding wall
of the packing box causes a force that is directed almost normal to the outer face
of the rim. This is completely distinct from the prior art package in which the rims
are oriented outwardly in a plane that is normal to the axis of the roll, so that
abutting contact of the outer edges of the rims with a wall of the box can cause a
corresponding rim portion to buckle, split or get a tortuous deformation. It should
be noted that suchlike local deformations of a sealed rim do not only have consequences
for the lighttightness of the wrapping but also for the unwinding characteristics
of the wound material. As a matter of fact, a sealed rim that has become seriously
buckled, or folded and next displaced inwardly of the roll, i.e. in the direction
of the opposite rim, will not become uniformly redressed by tearing off the circumferential
cover at the opening of the wrapping, so that further unwinding of the coiled strip
material will be hampered by periodic shockwise contact of the damaged rim portion
with the corresponding edge of the unwinding strip. This can damage the light-sensitive
coating of the unwound strip material, and/or disturb the smooth unwinding of the
strip and so its satisfactory exposure, e.g. by laser scanning, as it is being unwound.
[0009] The bent rims of the wrapping can be formed in different ways. According to one technique,
the rims are bent after they have been fitted to each other. A common procedure for
fitting the rims to each other is heatsealing. The bending of the rims can suitably
occur by rotating the wrapped roll about its axis and progressively bending the rims
by sliding or rolling contact with an appropriate deflector.
[0010] According to another technique, the rims are given their ultimate shape, or approximately
so, and then the rims are fitted to each other. The latter technique can afford a
bent rim which is more formproof than the first one.
[0011] However, whether one or the other technique is used and whether the bending of the
rims is small or large, the very fact that the rims do have a bending either towards
the circumferential or to an end cover make that the rims will exhibit a preferred
and controlled behaviour upon contact with a wall of the box, viz. the tendency to
further bend in a well-determined direction as a consequence of such contact.
[0012] Suitable embodiments of a packaged roll according to the invention are as follows.
[0013] The circumferential cover and the end covers have on their inside a thermoplastic
layer, and the fitting of the corresponding rims occurs by heatsealing such layers.
[0014] The circumferential edge of the rim of the end covers extends slightly beyond the
corresponding edge of the folded rim of the circumferential cover so hat the freely
exposed portion of the rim of the circumferential cover screens so to say the head
side of the sealed rim. This measure counts for rims folded towards the circumferential
cover. It is clear that for rims folded towards the end covers, it is desirable for
the circumferential cover to slightly extend beyond the end covers.
[0015] Packing a roll wrapped as described hereinbefore in a cardboard box without axial
support of the roll can cause dust by repeated frictional contact of the roll with
the inside surfaces of the walls of the box during transport and other manutentions
of the box.
[0016] Dust that is adherent to the lighttight wrapper of the roll becomes captured by e.g.
the velvet liners of the dispenser slot of the magazine into which the roll is loaded,
and will next be progressively transferred to a film as the latter is pulled out through
such liners.
[0017] The presence of dust is less critical for photographic paper than for photographic
film.
[0018] Therefore, according to a further preferred embodiment of the invention, a lighttightly
packaged roll of light-sensitive film is wrapped in a dustproof foil before it is
packed in a cardboard packing box. Such foil can be kept closed by means of overlapping
longitudinal margins, and by end portions tucked in the open ends of the core of the
wrapped roll. Such foil suitably is uncoloured in order to not mislead the user about
the actual purpose thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The invention will hereinafter be described by way of example with reference to the
accompanying drawings, wherein :
Fig. 1 is a perspective view of a prior art roll package,
Fig. 2 is a perspective view of one embodiment of an improved package according to
the present invention,
Fig. 3 is an enlarged view of detail 3 of Fig. 2,
Fig. 4 is a diagrammatic longitudinal sectional view of the package of Fig. 2 illustrating
the sealing of the rims of the lighttight wrapper,
Fig. 5 is a diagrammatic longitudinal sectional view illustrating the bent rims,
Fig.6 is the package of Fig. 2, wrapped in a dustproof foil, and
Fig. 7 shows the package of Fig 6 packed in a cardboard box.
DETAILED DESCRIPTION OF THE INVENTION
[0020] Referring to Fig. 1, a lighttightly packaged roll 10 of light-sensitive film comprises
two end covers 11 and 12, and a circumferential cover 13 sealed to said end covers,
as a lighttight wrapping for a light-sensitive film. Rim 14 of the central opening
of the end covers is lighttightly fitted to core 15 of the film roll. In the present
case, covers 11, 12 and 13 comprised an inner layer of polyethylene which allowed
heatsealing of the covers to each other and to the core. The packaged roll has a leader
16 protruding from the circumferential cover and allowing starting unwinding of the
roll after the roll has been placed in a suitable magazine. Roll 10 is packaged in
a shipping carton, not shown, by means of two supporting flanges having a hub engaging
the core opening and a diameter which is larger than the diameter of the end covers.
Sealed rims 17, 18 of the covers are urged by contact with the supporting flanges
in a plane normal to the axis of the roll, as shown. A roll package as described is
disclosed in US-A-4 733 777 mentioned in the introduction, and is on the market under
the trade name AGFA DATAREX of AGFA-GEVAERT N.V., Mortsel-Belgium.
[0021] Fig. 2 shows one embodiment of an improved roll package in accordance with the invention.
Parts having the same function as the corresponding parts of Fig. 1 received the same
numeral. In the present embodiment, the lighttight fitting of end covers 11 and 12
to core 15 occurred by means of lips 19 tucked in the core opening and heatsealed
to the inside surface of the core. The core of the film roll in the present embodiment
was made from cardboard, as distinct from the core of the Fig. 1 embodiment which
is a plastic one. The heatsealing of the end covers by means of lips 19 is disclosed
in EP Patent 0 350 093.
[0022] Also different from the Fig. 1 arrangement is roll leader 26 in Fig. 2 which now
is an extension of slightly reduced width of peripheral cover 13 and which is not
fitted to the end covers. Peripheral cover 13 itself is sealed to the end of the film
of the roll. This arrangement has the advantage that no film material is lost, contrary
to Fig. 1, upon loading a magazine and pulling until the peripheral cover has been
removed and the film comes out of the dispenser slot of the magazine.
[0023] Sealed rims 17 and 18 are bent towards circumferential cover 13 as shown diagrammatically
in detail in Fig. 3 which is an enlarged view of portion 3 of Fig. 2. Sealed rim 17
is an assembly of rim 21 of end cover 11 and of rim 22 of circumferential cover 13.
The fitting of both rims to each other occurred in the present example by heatsealing
the inside thermoplastic layers of both covers to each other, but can be done also
in other ways, such as by glueing, interposition of a two-sided adhesive ribbon or
the like.
[0024] The sealing of the rims can occur as shown in Fig. 4. End covers 11 and 12 are applied
against the lateral ends of wound roll 10 and fixed to the core thereof by means of
lips 19 that are sealed to the inside of the core. Next rims 21, 23 of both end covers
and 22, 24 of the circumferential cover are urged together at an angular position
of approximately 45° with respect to the end face of the roll, and sealed in this
position by means of two opposed heated roller pairs 25, 26 and 27, 28 shown in broken
lines which progressively seal the rims while the roll is rotated. This technique
has been described in US-A 4 733 777 mentioned hereinbefore. The rims are next bent
towards each other, i.e. in the direction towards circumferential cover 13, e.g. by
means of rolling or sliding contact with appropriate guides that deflect and bend
the rims. The material of the wrapping foils, in particular that of the end covers,
becomes stretched by this bending so that the rims maintain their bent shape.
[0025] According to another technique, the rims are bent in the desired direction and, while
in this position, their sealing is made. This has the advantage over the former technique
that a true "form sealing" is obtained which may keep its shape over a longer period
of time. The drawing of Fig. 5 shows such "form sealed" rims 17 and 18 and it will
be apparent that edge 29 of rim 21 is located slightly backwards with respect to corresponding
edge 30 of rim 22 because of its larger radius of curvature. In those cases wherein
the exposed extended portion of the inner rim could be the cause for damage of the
seal by contact with the adjacent wall of the shipping carton, as indicated diagrammatically
by arrow 31 for the lower side of the drawing, which represents a radial load, the
diameter of the end covers can be increased so as to obtain an "overlapped" seal as
illustrated diagrammatically in broken lines 32 in Fig. 5.
[0026] The film roll packaged and treated as described hereinbefore can then be wrapped
in a protective wrapping foil 34 as illustrated in Fig. 6. The foil has a rectangular
shape and the film roll is rolled in the foil with the two longitudinal foil margins,
running parallel to the roll axis, overlapping each other. One of these margins can
be provided with a self-adhesive, peelable seal 35, e.g. one obtained through fiberisation
of a self-adhesive hotmelt on such margin. Next the ends of the wrapper are tucked
in the open ends of the roll core.
[0027] The film roll thus wrapped is finally placed in a cardboard shipping carton 36 as
shown in Fig. 7, without use of conventional supporting flanges. The bent roll rims
are locally slightly flattened by their contact with the bottom wall of the carton
but this contact is in no way detrimental to the lighttightness of the wrapping since
the sealed rims only exhibit forces or components thereof that are normal or approximately
so to their surface. Movement of the film roll in the shipping carton during transport
and other manutentions may cause dust resulting from rubbing contact with the cardboard
walls, and this dust could settle on the lighttight wrapping of the film roll if there
were no protective wrapper 34 as shown in Fig. 6. Since this wrapper has no light
protecting function as such, it may be advantageous to use for this wrapper a translucent
or even transparent foil in order not to mislead the user of the film roll about the
actual function of the wrapper.
[0028] A film package according to the present invention is not limited to the illustrated
embodiment.
[0029] Referring to the drawings of Figs 3 and 5, it should be understood that the sealed
rims may be bent in the opposite direction as well, so that they get a shape wherein
their bending is towards the outer surface of the circumferential covers. Loading
of the sealed rims in a direction which runs parallel with, or nearly so, with the
axis of the film roll causes increased bending of the rims, without giving rise to
increased risk for destroying the lighttightness of the seals.
[0030] The lighttight fitting of the central opening of the end covers to the core can also
occur in other ways. As an example we refer to EU-A1-0 579 216 which discloses clamping
a margin of said opening into the core by means of a ring.
1. A lighttightly packaged roll (10) of light-sensitive strip material wound on a hollow
supporting core (15), which comprises a lighttight flexible end cover (11, 12) for
each end surface of the roll, each said end cover being lighttightly attached to the
corresponding end of the core, and each end cover further having a diameter in excess
of the diameter of the roll of wound material, and a lighttight flexible circumferential
cover (13) secured to the coiled strip material and covering the outermost convolution
thereof, said circumferential cover having a width in excess of the width of the wound
strip material, the inside faces of the rims (22, 24) of the circumferential cover
being fitted to the corresponding inside faces of the rims (21, 23) of the end covers
extending beyond the perimeter of the roll of wound strip material, characterized
in that the fitted rims of the lighttight wrapping thus formed have a bending all
along their circumference towards the outer surface of said wrapping.
2. A lighttightly packaged roll according to claim 1, wherein said fitted rims have a
bending towards the circumferential cover (13) of said wrapping.
3. A lighttightly packaged roll according to claim 1, wherein said fitted rims have a
bending towards the corresponding end covers (11, 12) of said wrapping.
4. A lighttightly packaged roll according to any of claims 1 to 3, wherein said rims
(21, 22, 23, 24) are fitted to each other by heatsealing.
5. A lighttightly packaged roll according to any of claims 1 to 4, wherein said bending
of said fitted rims has been obtained by preforming the rims prior to their fitting
to each other.
6. A lighttightly packaged roll according to any of claims 1 to 5, which is packed in
a cardboard box (36) without flanges supporting the roll out of contact with the walls
of the box.
7. A lighttightly packaged roll according to any of claims 1 to 6, which is additionally
wrapped in a dustproof wrapper.
8. A lighttightly packaged roll according to claim 7, wherein said wrapper is a foil
(34) having overlapping longitudinal margins, and end portions tucked in the open
ends of the core of the wrapped roll.
9. A lighttightly packaged roll according to claim 7 or 8, wherein said foil is transparent.
10. A lighttightly packaged roll according to any of claims 1 to 9, wherein said circumferential
cover (13) is attached to the leading end of the wound strip material and has a free
end (26) the rims of which are not secured to the end covers.