GB2292619A - Photographic film cassettes - Google Patents

Abstract

Film cassettes are well known for storing film strips before and after exposure of the film strip in a camera. However, once the film strip has been removed from the cassette for processing, the cassette is discarded. A film cassette (10) which can be used as an intermediate cassette for a processed film strip during photofinishing comprises a housing (12) in which a film strip (16) is mounted on a spool about a central axis (20). The housing (12) has an opening (14) which is closed by a flap (18). A rotatable shutter (22) is mounted on the axis (20) to shield the film strip (16) from light entering the housing (12) through the opening (14). The shutter (22) is moved between a first position as shown in which the film strip (16) is shielded to a second position in which access is allowed to the film strip (16) by means of lug on the shutter operated by a mechanism in a camera. <IMAGE>

Description

IMPROVEMENTS IN AND RELATING TO FILM CASSETTES Field of the Invention The present invention relates to improvements in and relating to film cassettes and is more particularly concerned with film cassettes which can be used many times.

Background of the Invention It is known to supply film strips in film cassettes, for example, film in 135 format (35mm).

Each cassette comprises a housing for a spool on which a film strip is wound, the housing having an opening through which the film strip can be extracted for exposure in a camera and returned to the cassette after exposure. One end of the film strip is attached to the spool and the other end, known as the film leader, is free and a portion thereof protrudes from the cassette. These cassettes also have means arranged around the opening for preventing light from entering into the cassette through the opening to expose and fog the film retained therein.

When placed in a camera, the film leader is further withdrawn from the cassette housing, either manually or automatically in the camera, to engage a spool forming part of the camera. The film strip is wound on to the spool in the camera as each frame thereof is exposed. After the film strip has been exposed, it is then wound back into the cassette housing, either manually or automatically by the camera mechanism. The cassette is then removed from the camera for processing of the film strip.

When the film strip in the cassette is to be processed, it is extracted from the cassette housing, detached from the spool, and passed through a series of treatment stages in photographic processing apparatus.

Problem to be solved by the Invention In known film cassettes described above, it is not possible to return the film strip to the cassette housing after it has been removed therefrom.

This means that the cassette housing and the spool on which the film strip was wound are then discarded.

Although, US-A-5 124 742 discloses an arrangement in which the film strip is processed while it is still attached to its spool inside the cassette.

The film strip is wound back into the cassette after processing is completed. However, processing of the film strip whilst still attached to the spool may cause problems as standard film processing apparatus cannot be employed.

Summary of the Invention It is therefore an object of the present invention to provide an improved film cassette into which a film strip can be re-inserted after it has been extracted, for example, after processing, so that the cassette can be used as a container for the film strip, for example, during a photofinishing operation.

In accordance with one aspect of the present invention, there is provided a film cassette comprising: - a housing for a film strip; spool means within the housing and on to which a film strip can be wound; an opening in the housing through which the film strip can be extended for exposure thereof in a camera and subsequently retracted after exposure; and light shielding means for preventing light reaching the film strip; characterised in that the light shielding means comprises a shutter mounted within the housing which is rotatable between a first position and a second position about an axis, the shutter shielding the film strip from the opening when in the first position.

Advantageously, the shutter includes a lug operable to be engaged by a mechanism in a camera to move the shutter between its first and second positions.

The shutter comprises a semi-cylindrical wall portion and two opposed end portions, each end portion having a respective portion which is aligned with and mounted on the axis.

Advantageous Effect of the Invention By this arrangement, the film strip can be protected from light by the light shield provided in the cassette. Furthermore, there is no need for any extra light shields at the opening of the cassette.

The cassette of the present invention has the advantage that it can be used as a storage device for the processed film during photofinishing, that is, in between the processing and printing stages.

Moreover, the cassette can be used as a permanent store for the developed film strip and is returned to the customer with the prints. This means that there is no need to cut the film strip into smaller lengths as is customary.

Brief Description of the Drawings For a better understanding of the present invention, reference will now be made, by way of example only, to the accompanying drawings in which: Figure 1 is a schematic illustration of a film cassette constructed in accordance with the present invention with an end removed; Figure 2 is a similar to Figure 1 but illustrating the leading edge of a film strip extending from the cassette; Figure 3 is similar to Figures 1 and 2, but illustrating the cassette when in a camera; and Figure 4 illustrates a shutter for use in the cassette shown in Figures 1 to 3.

Detailed Description of the Invention The present invention relates to a film cassette with an internal rotating shutter which prevents fogging of the film strip when the cassette is not in a camera. The shutter rotates about a central axis between two positions, light being prevented from reaching the film strip when in a first position, and the film strip being extractable from the cassette for exposure when the shutter is in a second position.

A film cassette 10 in accordance with the present invention is shown in Figure 1. The cassette 10 is shown ready for transport and daylight handling.

The cassette 10 comprises a housing 12 having an opening 14 through which a film strip 16 can be withdrawn from and re-inserted into the housing 12.

The opening 14 has a movable flap 18 attached thereto.

The flap 18 may be opened and closed by any suitable means (not shown). The film strip 16 is wound on a central core (not shown) having an axis 20. A rotatable shutter 22 is mounted in the housing 12 so as to be rotatable about axis 20, rotation of the shutter 22 being in the direction of arrow 24.

As shown in Figure 1, when the film cassette 10 is closed, shutter 22 is positioned so that the film strip 16 wound on to the spool is shielded from any light which may enter the opening 14 if the flap 18 is opened. The positioning of the shutter 22, however, allows a leading edge 26 of the film strip 16 to be outside the shutter 22 as shown. This is so that the leading edge 26 can be easily accessed when required.

Figure 2 shows the cassette 10 with the flap 18 partly open and the leading edge 26 of the film strip 16 extending from the housing 12. As before, the shutter 22 shields the film strip 16 on the spool from light entering the opening 14 as the flap 18 is open. The leading edge 26 of the film strip 16 is pulled out of the cassette 10 ready for loading into a camera (not shown).

Figure 3 shows the cassette 10 when loaded into a camera and ready for exposure. As shown, the shutter 22 has been rotated from its first position in the direction of arrow 24 (Figures 1 and 2) to its second position about axis 20. Flap 18 is fully open allowing free access to the film strip 16 in the housing 12. In order to return the shutter to its first position (Figures 1 and 2), it is rotated about axis 20 in the direction indicated by arrow 28.

The shutter 22 is moved between its first position (Figures 1 and 2) and its second position (Figure 3) by operation of an appropriate mechanism in a camera (not shown).

In Figure 4, the shutter 22 is shown in more detail. As shown, the shutter 22 comprises a wall portion 30 which forms half a cylinder having a circular cross-section, and two opposed end portions 32, 34 attached to the wall portion 30. Each end portion 32, 34 has a portion 36, 38 associated therewith and adapted to be aligned with and mounted on the axis 20. A pin or other suitable means (not shown) is used to mount the shutter 22 by way of portions 36, 38 with respect to the housing 12. One end 34 of the shutter 22 has a lug 40 formed thereon.

This lug 40 is operable to be engaged by an appropriate mechanism in the camera to move the shutter 22 between its first and second positions.

After the film strip 16 has been exposed in the camera, it can be wound back into the housing 12 as shown in Figure 3. Shutter 22 is then rotated back to its first position (Figure 2), in the direction of arrow 28, before the cassette 10 is removed from the camera. Flap 18 can then be closed until the film strip 16 is to be processed.

The film strip 16 is removed from the cassette 10 for processing in the normal way by rotating the shutter 22 to its second position when the cassette 10 is positioned in appropriate processing apparatus. The shutter 22 is operated by actuation means in the processing apparatus which engages with the lug 40 to rotate the shutter 22 about axis 20.

After processing, the film strip 16 can be returned to the cassette 10 for storage. This can be prior to or subsequent to a printing stage where the processed film strip is printed.

The cassette 10 can also be used as a receptacle for returning the processed film strip to customers together with the prints made therefrom.

If required, a secondary shutter (not shown) may be provided in the cassette 10. This secondary shutter acts as a dust shutter.

Claims (3)

ClAIMS:

1. A film cassette (10) comprising: a housing (12) for a film strip (16); spool means within the housing and on to which a film strip (16) can be wound; an opening (14) in the housing (12) through which the film strip (16) can be extended for exposure thereof in a camera and subsequently retracted after exposure; and light shielding means (22) for preventing light reaching the film strip (16); characterised in that the light shielding means (22) comprises a shutter mounted within the housing (12) which is rotatable between a first position and a second position about an axis (20), the shutter shielding the film strip (16) from the opening (14) when in the first position.

2. A cassette according to claim 1, wherein the shutter (22) includes a lug (40) operable to be engaged by a mechanism in a camera to move the shutter (22) between its first and second positions.

3. A cassette according to claim 1 or 2, wherein the shutter (22) comprises a semi-cylindrical wall portion (30) and two opposed end portions (32, 34), each end portion (32, 34) having a respective portion (36, 38) which is aligned with and mounted on the axis (20).