Note: Descriptions are shown in the official language in which they were submitted.
LZ38~13
DUAL WEB SOUND MOVIE CASSETTE
WITH EMULSION STRIPPING WEB
BACKGROUND OF THE INVENTION
This invention relates to audio/visual systems
and, more particularly, to an improved multipurpose, film
handling cassette for sound motion picture systems.
Motion picture systems including a multipurpose
film cassette in which a film strip is contained without
removal during exposure, processing and projection opera-
tions are described in prior V. S. Patent Nos. 3,615,127,
3,600,071, and 3,895,86~. In accordance with the dis-
10 closures of these patents, the film cassette is first placed
in a camera for exposure of the film strip therein in con-
ventional fashion. After exposure r the cassette is loaded
into a viewing device which first subjects the cassette to
a sequence of operations ~uring which the film strip is pro-
15 cessed to develop a series of image transparency ~rames.The same viewing device then projects the developed image
frames onto a screen for motion picture viewing.
The cassette system represented by the disclosure
of these prior patents may be provided with an audio capabili-
20 ty as disclosed in prior U. S. Patent Nos. 3,604,790 and3,856,387. In the audio/visual systems disclosed in these
latter patents, a magnetic sound recording track is provided
along one or both of the longitudinal borders of the cassette
contained film strip and the cassette includes a provision
25 for moving a loop of the film strip in operative relation-
ship with a transducing head forming part of an audio system.
~hile the arrangements disclosed in these patents provide
generally acceptable audio reproduction, the narrow width
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of the audio tracks necessitated by their being carried
directly on the film strip limits the level of sound quaiity
which may be achieved or, conversely r increases the degree
of sophistication or cost required of the audio system to
5 achieve high fidelity.
The sound track dimensional limitations o~ the
prior systems may be solved by providing in the cassette
a separate audio tape in addition to the usual photographic
film strip. Both the tape and the strip may extend between,
10 and may be interwound in nesting convolutions on, cassette
contained supply and takeup spools. In this way, both the
tape and the film strip may be simultaneously wound or
unwound from the respective spools but the path through
which the sound tape passes between the spools is different
15 from that of the film strip. In particular, the film strip
travels through a path including an exposure/projection
station whereas the sound tape travels in a path including
an audio transducing head and drive capstan.
The principal difficulty encountered with such
20 dual web systems in the multipurpose cassettes having a
provision for processing the motion picture film strip is
the tendency for the sound tape to adhere to the emulsion
or, at least, to processing fluid on the film strip emulsion
during the period just following the deposition of process-
25 ing fluid on the film strip. This problem may be overcomeby providing a mechanical stripping device for separating
the sound tape from the film strip. Relative movement of
the mechanical stripping device and the film strip, howeverr
is likely to produce an undesirable wearing and possibly
30 damage to one or both webs, particularly after repeated
projection cycles.
The film strip currently used in the system is an
additive color film structure including, in the order of
light transmission during exposure, a transparent pol~ester
35 carrier base, an additive color screen, a processing fluid
barrier layer, a positive image receiving layer or inter-
face, a sil~er halide emulsion or negative image receiving
layer, and an inner layex of antihalation dyes and image
stabilizer. When processed by coating the inner layer with
_3~ 38~
a thin uniform layer of processing fluid or liquid, the
chemicals contained in the processing fluid permeate the
inner layer to the emulsion to develop exposed silver
halide grains and render them essentially transparent.
S Unexposed silver halide grains migrate by dif~usion to khe
positive image-receiving interface at which they are trans-
formed into an opaque silver image in varying degrees o
density. During and after development of the images, the
antihalation dyes in the inner layer are bleachea to become
10 colorless. The negative image in the emulsion is
sufficiently low in covering power relative to the positive
image that the film strip may be viewed by projection of
light in a direction proceeding through the inner layer, the
processed emulsion layer and the remaining positive image
15 carrying portions of the film strip and the color screen.
The presence of the spent emulsion layers on the
film strip after processing and during projection can be
characterized as a compromise between advantages to be
gained by removal of these layers and difficulties hereto-
20 fore experienced in achieving their removal while retainingthe desirable characteristics of the present system, par-
ticularly those characteristics attributed to the retention
at all times of the film strip in the same cassette in which
it was initially packaged. A principal advantage to be
25 gained by removing the spent inner emulsion layers is
greater transmissibility of the processed film during pro-
jection. The problems resulting from retention of the spent
inner and emulsion layers on the processed film strip have
been recognized previously and dealt with by stripping these
30 layeLs from the film a~ter processing. See, for example,
U. S. Patent Nos. 3,455,633; 3,7Q9,588, and 3,711,192.
~238VB
~ ong the objects of the present invention, are therefore, the pro-
vision of an improved multipurpose ilm cassette capable of use with audio/visual
apparatus; the provision o such a film cassette in wh~ch a sound tape may be
wound with a film strip immediately after the deposi~ion of a process~ng liquid
thereon without adherence of the sound strip to the film strip; the provision o
an improved web stripping arrangement for removing negative emulsion in dual web
photographic film cassettes; and the provision of such an improved arrangement
which is low in cost, easy to adapt to existing cassette designs, and trouble-
free in operation.
In accordance with the present invention, the problems associated with
dual web multipurpose film cassettes and with stripping or removing of negative
emulsion layers are alleviated by providing a third, separating and stripping
web extending between the cassette-contained supply and takeup spools with the
sound tape and film strip. The separating web is interposed between the tape
and the film emulsion surface, and passes between the spools under tension ad-
equate to assure ready separation of the separating web and the negative emulsion
from the film strip in a smooth and posi.tive manner without interfering in any
way with the operation of the cassette in any of i*s several modes of operation.
The ssparating web is interposed between the emulsion side of the film strip snd
the sound tape so that when the three webs are wouncl in nesting or interleaved
convolutions on either one or both of the supply and takeup spools~ one side of
the sound tape is in contact with the dry carrier side of khe ilm strip whereas
the other side of the sound tape is in contact with the separating web.
More particularly, the present invent~on provides in a photographic
film cassette having a film strip coupled at opposite ends to a cassette-contain-
ed supply and takeup spools upon which the fllm strip may be alternat~ly wound
and unwound for movement between the spools in a fi~st path through a photographic
station, the film strip including an emulsion surface, khe cas~ette including a
~ _ 4 _
llZ~
processing station operative after film exposurc to deposit a thin layer of
processing fluid on the emulsion surface of the film str.ip, the film strip hav-
ing a carrier base to suppor-t a plurality of layers :including a light sensitive
emulsion acted upon by the processing fluid and positive lmag~ fo~ming layers
located between the carrier base and the ligh~ sensitive emulslon~ the cassette
further including an audio tape coupled at one end to at least one of said
spools for interwinding thereon with the film strip and extending along a second
path through an audio station, the improvement comprising: a stripping and sep-
arating web of thin flexible material having one end coupled to said one spool
for interwinding thereon with the film strip and the audio tapo in an interleaved
manner interposed between the audio tape and said emulsion surface of said one
side of the film strip, the stripping and separating web being movable from the
one spool in a third path separate from the first and second paths so that during
rewinding and processing of the film strip in convolutions on the supply spool,
said stripping web overlies the inner layers of the film strip now wetted with
processing fluid and upon subsequent unwinding of both the film strip and said
stripping web and corresponding kravel in their separate paths, diverging sep-
aration of said stripping web from the film s~rip causes at least a portion of
the light sensitive emulsion to be retained by adhesion on said stripping web.
The invention will IIOW be described in greater detail with reference
to the accompanying drawings.
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~RIEF DESCRIPTION OF THE DRAWI~GS
_.
Figure l is a cutaway side elevat.ion illustrating
the interior components of a multipurpose film cassette
incorporating a separating and stripping web in accordance
5 with the present invention;
Figure 2 is a fragmentary side elevation similar
to Figure l but with the components in a different condition
of operation;
Figure 3 is an enlarged CEOSS section on line 3-3
10 of Figure l;
Figure 4 is a greatly enlarged fragmentary cross-
section of the film strip and separating web taken on line
2-2 of Figure 2;
Figure 5 is a cross-section of the sQparating and
15 stripping web of Figure 1, but showing film components
carried by the stripping web after film processing and
stripping; and
Figure 6 is a cross-section of processed film
after processing and stripping.
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DETAILED DESCRIPTION OF THE PRE:FEE~RED EMBODIMENT
In Figure 1 of the drawings, an embodiment of the
present invention is shown in a multipurpose film cassette
of a type similar to those described in the aforementioned
5 patents. ~s such, the cassette includes an exterior hous-
ing 10 defined by planar side walls 14 and 16 joine~ by end
walls 18 and 20 and by elongated top and bottom walls 22
and 24, respectively. Rotatably supported on parallel axes
between the side walls 14 and 16 are supply and takeup
10 spools 26 and 28, respectively, to which opposite ends of a
photographic film strip 30 are attached. The path of the
film strip 30 between the supply and takeup spools extends
from the supply spool 26 about a bobulator roller 32, an
idler roller 34, through a flight along the interior of the
15 bottom wall 24, about a snubbing roller 36 ancl ~inally to
the takeup spool 28.
In its flight between the idler roller 34 and the
snubbing roller 36, the film strip 30 passes through a photo-
graphic station including a processing station 38 which
20 includes a reservoir 40 for containing a supply of process-
ing fluid such as an aqueous processin~ liquid adapted to
be applied to the emulsion side of the film strip 30 through
a nozzle 42. Also shown in Figure 1 is a valve assembly 44
movable by the film strip 30 during the terminal portions
25 of a processing cycle to a position closing the nozzle 42.
After passing the processing station 38 during
travel through the photographic station in a direction pro-
ceediny rom the supply spool 26 to the takeup spool 28,
the film strip 30 passes an exposure~projection station 46,
30 which includes an opening 48 in the bottom wall 24 through
which light may pass both during exposure of the film strip
in a motion picture camera (not shown) and during projection
in a viewing device (not shown). In this latter respect,
the station ~6 includes an opening 50 through which light
35 from a projector is passed to a reflecting prism 52 through
the film strip and the opening 4~.
Inasmuch as the operation of the cassette during
exposure, processing and projection of the film strip 30
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is fully described in one or more of the aforementioned
patents, these operations will be only cursorily summarized
herein. In particular, when the cassette is loaded in an
appropriate camera, the film strip travels through its path
5 from the supply spool 26 to the takeup spool 28 Eor exposure
of successive image frames at the station 46. When the
film strip 30 is so exposed, it will be wound on the supply
spool 28. The cassette is then removed from the camera and
placed in the viewing device of the system which programs
10 a processing cycle during which the film strip 30 is rewound
from the takeup spool 28 to the supply spool 26. During
the initial portion of such rewinding, the processing station
38 is activated and ~he emulsion side of the film strip will
be coated with a layer of processing fluid as the strip is
15 rewound on the supply spool 26. Thereafter, the direction
of film strip travel is reversed for projection of the
developed images thereon.
To provide for an audio capability, the illus-
trated multipurpose cassette is provided with a separate
20 audio tape 54 having an oxide coating 55 (shown in Figure 3).
The tape 54 is a flexible web of the same width as the film
strip 30 and is interwound with the film strip 30, in the
disclosed embodiment, on both the supply and takeup spools~
26 and 28. In this respect, opposite ends of both the film
25 strip 30 and the audio tape 54 are secured in overlying
relationship to both the supply and takeup spools in the
cassette illustrated. While both webs are coupled to the
spool, only one of the wébs (i.e., the Eilm strip) need be
directly comlected to the spool while the other web (i.e.,
30 the tape) may be connected to the first at a point close
to the latter's spool connection.
In Figure 1 of the drawings, both the strip 30 and
the tape 54 are illustrated in their relative conditions in
an unused or rewound cassette in which both webs are on the
35 supply spool 26. The path through which the audio tape 5~,
however, extends from the supply spool to the takeup spool 28
diverges from that taken by the film strip 30~ In particular,
the audio tape proceeds ~rom the supply spool upwardly
-8- ~ ~ 2 ~ 8 ~ 8
through a tape exit opening 56, past an audio station 58
defined in part by an opening in the top wall 22 of the
casse-tte housing 10, to a cassette entry opening 60 where
it re-enters the cassette and passes to its point of
5 attachment with the takeup spool 28. The exit 56 and the
entry 60 are established in part by a light shielding
baffle 62 having low friction guiding surfaces 61 and 63
at opposite ends and spanning the opening 58 i.n the top
wall 2~ of the cassette.
The path of the audio tape 54 may alternately
extend from the supply spool, past an audio station to a
second takeup spool (not shown) separate from the film
takeup spool 28. In such a cassette, only one end of the
audio tape is connected to the supply spool, but the same
15 interwindin~ of the audio tape and the film strip will occur
during processing and/or rewinding of the film strip from
the takeup spool 28 back to the supply spool 26.
Suitable audio components carried by either or
both the photographic camera and the viewing device with
20 ~Ihich the cassette is to be used are illustrated in respec-
tive inactive and operative conditions in Figures 1 and 2
of the drawings. As schematically shown in these figures,
the audio components include a drive capstan 64 and a backup
idler roller 66 which, when closed on one anot~er, operate
25 to advance the audio tape 54 at uniform speed pas~ a trans-
ducing head 68~ A head backup pad 70 supported by a member
72 extending between a pair of head backup rollers 74 retain
the audio tape in operative engagement with the transducer
head as illustrated in Figure 2. An idler backup roller 76
30 engages one of the backup pad carrying rollers when the
system is operative as illustrated in Figure 2. In its
initial condition as shown in Figure 1, the audio tape 54
extends through loop portion 54a which is sufficiently stiff,
at least over the initial portion thereof t to assume ~he
35 bowed configuration in the-opening 58 of the cassette hous-
ing so as to permit convenient insertion of appropriate audio
components under the tape web 54. The loop 54a, as may be
seen in Figure 2, allows the audio tape 54 to be passed
~12;~
continuously at a constant speed past the transducer head 68
in operation irrespective of whether it is pa.id out ~rom the
supply spool at a constant speed.
It has been recognized that the in-terwinding of
5 the sound tape 5~1 with the film strip 30, particularly on
the supply spool as an incident to film strip processing,
gives rise to the problem of the sound tape sticking ~o the
wet side of the film or, wet processing fluid applied to the
film strip immediately in advance of its being rewound onto
lO the supply spool 26. In accordance with the present inven-
tion, this problem as well as stripping of the negative emul-
sion, is effectively solved by interwind.~ng with the audio
and film webs, a third or separating web 80.
The separating and stripping web 80 is a flexible
15 strip of, for example, plastic material such as Mylar,
approximately equal in width to the film strip 30 and the
tape web 54, and preferably inert and impervious to the pro-
cessing fluid (designated as 30p in Figure 3). Advantageously
like the film and tape, the separator web 80 need only be
20 coupled to the spool and may be connected to one or both of
the other strips near their spool end, rather than directly
connected to the spool itself.
In the embodiment shown in both Figures l and 2 of
the drawings, the separating web 80 extends directly from
25 the supply spool 26 to the takeup spool ~8 and is preferably
guided along a separate path and maintained under tension
with respect to both spools by a leaf spring S2 or other
equivalent means secured to the front or back wall 14 or 16
of the cassette housing interior between the supply and
30 takeup spools 26 and 28. In the illustrated embodiment, the
tensioning spring 82 is in the nature of a flexible leaf
spring cantilevered from a mounting boss 84 and having an
anti-friction guide 86 at its projecting end.
In Figure 3, the respective webs are s~own ~reatly
35 enlarged. By comparing Figure 3 and Figure l, it will be
seen that as the three webs are rewound onto the supply
spool 26 during processing of the film strip 30, the layer
of processing fluid 30p (Figure 3) will be presented in an
*Trade mark
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outwarclly facing direction as the strip 30 is initially
wound on the supply spool 26. The separating web 80 will
then overlie the film emulsion surface which becomes wetted
with the processing fluicl. At the same time, the audio
5 tape 5~ will be interwound on the supply spool with one
surface engaging the separating web 80 and the other sur-
face (i.e., its oxide coating 55) contacting the base or
always dry surface of the film strip 30. In this way, the
audio tape 5~ is never brought into direct contact with
10 the emulsion or the wet processing fluid layer 30p. It
should be noted that the thickness of the processing layer
30p is exaggerated in Figures 3-6 for clarity; however,
in practice the layer is initially less than .00127 mm
and is to a large extent, quickly absorbed into the emul-
15 sion surface of the film.
In the operation of the cassette incorporatingthe separating web 80 of the present invention, both the
film strip and the audio tape may pass from the supply
spool to the takeup spool in the manner aforementioned.
20 The separating web 80, being under a slight tension, will
pass in an essentially tangential path from the supply
spool and strip away the negative emulsion layers from the
film strip.
In Figure 4, the details of various functioning
25 la~ers of photographic material of the film strip is
depicted after it has been rewound past the processing
station 40, but with the scale of various layers being
exaggerated with respect to those illustrated in Figure 3
The ~ilm strip 30 is constituted by a base layer providing
30 a transparent polyester carrier base 86 through which
light is passed in the direction of the arrow 87 during
film strip exposure. In the order of such exposure light
transmission, the carrier base 86 is followed by a color
screen layer 88 which in practice is constituted by a
35 series of red, green, and blue lines. Superimposed
successively on the color screen are a processing fluid
barrier layer ~0, a positive image receiving layer 92
depicted in Figure ~ with a positive silver image, a
2~8~8
--11--
release coat 9~, a negative or light sensitive emulsion
layer 96, depicted in Figure 4 wi-th a negative image of low
covering power, and a cover layer 98 initially containing
antihalation dyes and an image stabilizer. Principally to
5 provide an understanding of the surface on whiah the pro
cessing fluid 30p is applied to the film strip 30, the pro-
cessing fluid is also depicted as a layer although at this
stage of the development, much of this layer has been
imbibed into the film emulsion. Finally, the web 80 is
10 illustrated in overlying relation to the inner layer 98
with the processing fluid interposed therebetween.
The release coat 94 may be an alkali-degradable
wax or other coating, which is at least partially dissolved
or degraded by the alkaline processing liquid 30p such that
15 after processing, the release coat 94 reduces the adhesion
between the positive image layer 92 and the negative image
layer 96 so that such adhesion is less than the adhesion of
the web 80 to the wetted emulsion, that is, to the cover
layer 98. In this regard, the adhesion between the web 80
20 and the wet processed film is facilitated by the imbibition
period during which the wet film and web are retained in a
wound condition on the supply spool, just following the
processing rewind, for a short time period of approximately
10 to 30 seconds to aid image development.
As mentioned previously, the development of the
positive silver lmage in the layer 92 is as a result of the
processing fluid diffusion through the cover layer 98 to
the emulsion layer 96 where exposed grains of silver halide
contained therein are developed and unexposed grains are
30 dissolved and caused to migrate by diffusion transfer to the
positive image receiving layer 92 where they are transformed
into a variably opaque silver positive image. The layers 96
and 98, after processing, are essentially transparent but
result in a measure of light attenuation when the ~ilm strip
35 is projected by light passing in a direction in the reverse
of the arrow 87.
Because of the manner in which the web 80 is inter-
wound with the film strip 30, it will be observed by refer-
ence to Figures 1 and 2 of the drawings, that as the film
~lZ38g~8
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strip 30 is wound (from left to right) on the supply spool
26 during rewind with its deposition of the processing fluid
30p thereon, the weh 80 will travel also from the takeup
spool 26 to the supply spool and overlie the cover layer 98
5 as well as the residual processing fluid 30p on the cover
layer at this time.
Then, as the left-to-right direction of web travel
is again reversed to right-to-left travel, such as during a
mandatory projection cycle, the Eilm strip 30 will pay off
10 from the supply spool 26 through the film path to the takeup
spool 28. The stripping web 80~ however, in passing along
its own path to the takeup spool 28, will diverge from or
part from the film strip 30 and carry with it the spent
inner layer 98 and emulsion layer 96 as shown in Figure 5.
15 This parting of such layers from the remaining layers of the
film strip will result in part from the action of the release
coat 94.
In Figures 5 and 6 of the drawings, the layers of
photographic material separately carried by the stripping
20 web 80 and the carrier base 86 of the film strip 30 are
illustrated. Thus, in Figure 5, the layers of material dis-
posed inwardly of the release coat 94, specificaIly the
spent emulsion layer 96 as well as the used cover layer 98,
are attached by adhesion to the stripping web 80. Likewise
25 as shown in Figure 6, layers necessary to the vièwing of a
positive color image, such as the color screen 88 and the
positive image receiving layer 92 remain with the carrier
base 86 of the film strip. The separation of the layers 96
and 98 from the film strip 30 occurs naturally as a result
30 o the tacky characteristics of the inner surface of the
film, at least after the processing fluid 30p has been
deposited on the film strip. This separation is, of course,
augmented by the provision in the film strip of the release
coat 94 between the image layers 92 and 96.
As a result of the separation or stripping of the
layers 96 and 9g from the film strip 30, the lat-ter only
retains the base 86, the screen 88, the fluid barrier 90, and
the pos:itive layer 92, as noted in Figure 6. Consequently,
~ 38~8
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during the projection cycle following the processing opera-
tion, projection light passing in the direction of the
arrow 82 will now pass only through the components of the
film strip which are necessary to recreate the developed
S positive image formed in the layer 92. As a result,
attenuation of light by the spent cover and emulsion l~yers
is avoided. During the first projection cycle, as the web
80 is rewound with the film strip 30 on the takeup spool,
any tendency for the layers 96 and 98 carried by this web
10 to readhere to the film strip is reduced by virtue of the
continued drying of the components. During subsequent rewind
and projection cycles, the web 80 will merely be wound and
rewouna with the now developed film strip and the sound
tape 54 without interference with projection and rewind
15 operations.
As a result of this invention, a highly effective
and readily adapted stripping apparatus is provided by which
the aforementioned objectives are completely ful~illed. It
is contemplated that modifications and/or changes may be
20 made in the embodiment illustrated and described herein
without departure from the substance of the present inven-
tion. It is expressly intendedr therefore, thàt the fore-
going description is illustrative of a preferred embodiment
only, not limiting, and that the true spirit and scope of
25-the present invention be determined by reference to the
appended claims.
