Photography – Disposable or recyclable camera
Reexamination Certificate
1996-02-26
2001-05-15
Mathews, Alan A. (Department: 2851)
Photography
Disposable or recyclable camera
C396S284000, C396S395000, C396S401000, C396S411000
Reexamination Certificate
active
06233400
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lens-fitted photographic film unit and a method of manufacturing the same. More particularly, the present invention relates to a lens-fitted film unit with which a user can take more photographs than a standard number of the photographable frames of the strip of photographic film contained therein, and a method of manufacturing such a film unit.
2. Description Related to the Prior Art
A 135-type photographic filmstrip (hereinafter referred to as film) in a cassette as defined by ISO code 1007, 1979 version, is given a standard number of photographable frames and a length sufficient for such frames (ISO signifies International Organization for Standardization). A user takes photographs to expose a series of the standard number of frames on the film. There are, however, occasions on which a conventional camera happens to take on standard film one or two exposures in addition to the standard number of exposures. Because such a conventional camera is manually loaded with film by a user, it is impossible, after completing exposure of the film, to estimate with precision the position of the picture frame nearest to the film leader. Thus it cannot be known how much leader can be pulled out of a cassette for development without accidental exposure of a picture to ambient light. In consideration of this, the prevailing standard provides an allowance of film beyond the length sufficient for the nominal number of exposures.
The available length of the film is defined as the distance between the mouth of the cassette and the film leader when the film is fully drawn out of the cassette. As pointed out above, this available length is set to be longer than the series of the stated number of frames, and includes a lengthwise allowance to be left unexposed, which is approximately four times as long as a single frame. It is therefore possible in a camera to make on a film one to three exposures in addition to the stated number of exposures, which is dependent upon a manner of loading the camera with the film.
Lens-fitted photographic film units (hereinafter referred to simply as film units) are now on the market, e.g. under the trademark “Quick Snap” (manufactured by Fuji Photo Film Co., Ltd.). Such known film units are disclosed in e.g. U.S. Pat. Nos. 4,884,087 and 4,972,649, and are a single-use camera preloaded with photographic film. Such a film unit has a film housing of which a front cover and a rear cover are secured to a main body, in which body a taking lens, a film wind-up wheel and a shutter mechanism are incorporated. The main body is provided with a film supply chamber and a cassette-containing chamber formed on opposite horizontal sides of the taking lens. The unexposed film is wound in a roll in the film supply chamber. The externally rotatable wind-up wheel is engaged with a spool in the cassette contained in the film take-up chamber. A user who has purchased the film unit winds the film frame by frame back into the cassette after each exposure.
A driven sprocket wheel engages perforations in the film, and, when the film is wound up, is rotated by the moving film. When the film is wound up by one frame, namely eight perforations, responsive rotation of the sprocket causes a wind-up stopping mechanism to prevent the wind-up wheel from rotating further, cocks the shutter mechanism, and steps the count of a count-indicating wheel.
The film unit as manufactured must be inspected before it can be shipped, because the film unit should be usable with high reliability, without difficulties caused by manufacture of the film unit. It is usual to inspect the operation of the shutter mechanism. After the main body is loaded with the drawn-out film and its cassette, the shutter mechanism is cocked and then released, so as to check the operation.
There is a problem in this inspection of the film unit to be shipped. Cocking and releasing of the shutter mechanism for checking the operation must spend one frame of the film, with a length of eight perforations, and thus reduces the lengthwise allowance of the film available for possible exposures in addition to the stated number of photographable frames. If inspection other than the operation of the shutter of the film unit is performed, more than one frame will be spent.
OBJECT OF THE INVENTION
In view of the foregoing problems, an object of the present invention is to provide a method of manufacturing a lens-fitted photographic film unit, which method is suitable for enabling a user to take more photographs than the stated number of photographable frames for the strip of photographic film contained therein.
SUMMARY OF THE INVENTION
The present invention permits utilizing nearly the full length of the film in a lens-fitted photographic film unit, which has been loaded with the film by the manufacturer in a darkroom by a process in accordance with the present invention. Heretofore, no film unit has been known which is capable of making on a photographic film one or several more exposures than the stated number of exposures of the film, although about six years have passed since the beginning of marketing of lens-fitted photographic film units.
The lens-fitted film unit of the present invention includes a sprocket in mesh with perforations in the photographic film and rotated through a predetermined angle when the photographic film is advanced one frame, and includes a shutter mechanism that is cocked responsive to rotation of the sprocket. The manufacturing method includes first and second steps. The first step consists in setting the sprocket in a first rotated position in order to bring the shutter mechanism into a first cocking state. The second step consists in, after the first step, loading the photographic film.
In a preferred embodiment, the shutter mechanism is cocked in that first cocking state. Subsequently, the photographic film is loaded while the shutter mechanism remains cocked.
In another preferred embodiment, the first rotated position of the sprocket is N teeth before the position of the sprocket at the end of one winding up of the film, wherein the sprocket has eight teeth, and 1≦N≦7. The shutter mechanism in the first rotated position of the sprocket is in this instance incompletely cocked.
This construction is favorable for manufacturing the film unit, because only a small portion of the film is spent for inspection of the shutter mechanism. There is no reduction in lengthwise allowance of the film available for exposures in addition to the stated number of photographable frames. A user can take more photographs than the stated number of photographable frames of the strip of photographic film.
Inspection other than that of the shutter operation of the film unit may confirm and evaluate the torque for rotation of the wind-up wheel after loading of the film. Because the wind-up wheel would be rotated for such inspection in a conventional manufacture, almost two frames might be spent for inspection of both the wind-up wheel and the shutter mechanism. In the present invention, however, there is still no reduction in lengthwise allowance of the film available for exposures in addition to the stated number of photographable frames.
Furthermore, a film passageway is formed between the main body and the rear cover for passage of the film. An engaging member is arranged to project into the film passageway in retractable fashion. A notch is formed in an edge of the film, for engagement with the projected engaging member, in order to retain the film in the film passageway, and is adapted, upon the loading of the main body with the film, to position the unexposed film in a lengthwise direction within the film passageway.
In a film cassette in which film is to be used for additional exposures, drawing out the film leader during development by the usual length might subject to ambient light the frame nearest to the film leader in a conventional construction. But in the present invention, the film is positioned relative to the driven sprocket asso
Iwamoto Shoji
Muramatsu Katsuji
Fuji Photo Film Co. , Ltd.
Mathews Alan A.
Young & Thompson
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