JPS6257976B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a film winding device for a camera.

In recent years, film winding devices have been used that automatically wind the film by rotating a film winding shaft by a predetermined angle when one frame of film is photographed in a camera. Here, the rotation angle of the film take-up shaft is kept constant, but as the film winding progresses, the effective diameter of the take-up shaft increases, so the film feed amount per revolution of the take-up shaft is will increase. That is, as the winding of the film progresses, the distance between the frames of the film increases, and the unused portions between the frames of the film increase, resulting in a decrease in the number of images that can be taken with one film. This was particularly an economic problem in the case of special and expensive films such as photographic films for endoscopes.

The present invention has been made to address the above-mentioned circumstances, and an object of the present invention is to provide a film winding device that reduces the rotation angle of the film winding shaft as the number of film frames increases. .

Hereinafter, one embodiment of a film winding device according to the present invention will be described with reference to the drawings. Here, it is assumed that the film is a cartridge film contained in a magazine. FIG. 1 is an explanatory diagram of a film magazine and its winding device. A release switch 10, which is closed in response to depression of a release button (not shown), is connected to a counter 12 and a shutter control circuit 14. The counter output of the counter 12 is supplied to an address input terminal of a read only memory (ROM) 16, and the data output of the ROM 16 is supplied to a driver circuit 18. Further, the shutter control circuit 14 is connected to a driver circuit 18, and the driver circuit 18 supplies a drive signal to the pulse motor 20. Due to space constraints, the pulse motor 20 is disposed at a position where its rotating shaft is perpendicular to the film winding shaft 24 in the film magazine 22. The direction of rotation of the pulse motor 20 is changed and decelerated via a worm gear 26 and a worm wheel 28. The film winding shaft 24 passes through the bottom of the film magazine 22, and the worm wheel 28 has a pawl 30.
are connected to each other, so that the rotation of the pulse motor 20 is transmitted to the film winding shaft 24. A window 32 is provided on the film photosensitive surface side of the film magazine 22, and an image of the subject is formed on the photosensitive surface of the film 34 through this window 32 by a photographing lens (not shown). The film winding shaft 24 winds up the film 34 by the length of the window 32 in one winding.

Next, the operation of one embodiment of the film winding device according to the present invention constructed as described above will be explained.
First, when the release switch 10 is closed, the shutter control circuit 14 is energized and a shutter (not shown) is opened to perform exposure. When the shutter is closed and exposure is completed, the shutter control circuit 14
supplies an exposure end signal to the driver circuit 18.
This release switch 10 is opened again when exposure is completed. On the other hand, since the release switch 10 is also connected to the counter 12, the counter 1
2 is supplied with a pulse signal corresponding to the operation of the shutter. That is, the counter 12 counts the number of photographed frames of the film, and as this count increases, the counter output also increases in the order of 0, 1, 2, . . . . The address of the ROM 16 is specified by this counter output. Here, ROM16 has 1000 at address 1 and 2
Data is stored in such a way that as the number of addresses increases, the data value decreases, such as 980 for the address, 962 for the third address, etc. Then, the data at the designated address is supplied to the driver circuit 18, and the driver circuit 18 drives the pulse motor 20 in accordance with the data output on the condition that the exposure end signal described above is supplied. The film winding shaft 24 is rotated by the rotation of the pulse motor 20, and the film 34 is wound up. The amount of winding, that is, the amount of rotation of the pulse motor 20 is determined by the data in the ROM 16. Therefore, as in this embodiment, ROM16
stores data that decreases as the number of frames increases, and by specifying an address corresponding to the number of frames to be photographed, the amount of rotation of the film winding shaft 24 is decreased in accordance with the increase in the number of frames to be photographed. The distance between pieces can be kept constant.

Note that the thickness of the film 34 generally varies depending on the type. Therefore, it is fine if a single type of film is used, but if two or more types of film are used, it is necessary to change the contents of the ROM 16 depending on the thickness. For this purpose, either a film type detection means or a film type specifying means is provided and a calculation is performed on the data output of the ROM 16 according to the output of these means, or a plurality of data sets corresponding to the film type are stored in the ROM 16. Then, the read address of the ROM 16 may be changed in accordance with the output of the film type detection means or the like.

In addition, in FIG. 1, the unshot film 34 in the film magazine 22 is simply wound, but the film is wound around a film supply shaft having a brake means such as a felt disc, and tension is applied when the film is wound. By doing so, the film is wound onto the film winding shaft 24 in close contact with each other, so that the actual diameter of the winding shaft 24 does not vary and the film frame spacing becomes more accurate.

Next, a second embodiment of the film winding device according to the present invention will be described with reference to FIG. Here, the same parts as in the first embodiment are given the same reference numerals, and the explanation thereof will be omitted. In this embodiment, the film winding shaft is rotated by a general DC motor instead of a pulse motor. An exposure end signal output from the shutter control circuit 14 is connected to a driver circuit 36, and the driver circuit 36 supplies a drive signal to a DC motor 38. A disk 40 is also attached to the rotating shaft of the DC motor 38 along with the worm gear 26 . The disk 40 has a hole 42 formed at one location, and a light emitting element 44 such as a lamp or a light emitting diode and a light receiving element 46 such as a phototransistor are placed facing each other across the hole 42. Light receiving element 46
is connected to a counter 48, and the counter output is supplied to one input terminal of a comparator 50. The other input terminal of the comparator 50 is supplied with the data output of the ROM 16 whose address is specified by the counter output of the counter 12 that counts the opening and closing of the release switch 10.

The operation of the second embodiment configured as described above will be explained below. When the exposure is completed, an exposure completion signal is supplied from the shutter control circuit 14 to the driver circuit 36, and in response, the driver circuit 36 rotates the DC motor 38 at a constant speed. When the DC motor 38 rotates, the film winding shaft 24 is rotated via the worm gear 26, worm wheel 28, and pawl 30, and the film 34 is wound up. On the other hand, since the disk 40 also rotates, the light emitting element 44
The light emitted from the disk and received by the light receiving element 46 is blocked by the portions of the disk 40 other than the hole 42. As a result, the light receiving element 46 outputs a light receiving signal having one pulse per rotation of the disk 40. Since this light reception signal is supplied to the counter 48, the counter 48 counts the number of rotations of the DC motor 38.
The counter output of the counter 48 and the data output of the ROM 16 are compared by a comparator 50, and when they match, the comparator 50 supplies a match signal to the driver circuit 36. When the driver circuit 36 is supplied with this coincidence signal, it stops driving the DC motor 38. That is, by changing the data in the ROM 16 in accordance with the number of frames to be photographed, the amount of winding of the film can be changed in accordance with the number of frames to be photographed, and the interval between frames of the film can be made constant. for example,
Since the address designation signal of the ROM 16 is a signal corresponding to the number of frames to be photographed, the ROM 16 only needs to store data such that the data value decreases as the number of addresses increases, as in the first embodiment. . However, in this case, the counter 48 that counts the number of rotations of the DC motor needs to be reset to 0 every time one frame of film is wound, but if the ROM 16 stores the data cumulatively, There is no need to reset it every time you wind it. For example, 1000 at address 1, 1980 at address 2, and 1980 at address 3.
2942, etc., there is no need to reset it except when starting to use a new film.
When starting to use this new film, first
Similarly, in the case of the embodiment described above, it is necessary to reset the counter 12 that counts the number of photographed frames.

Although the above description has been made regarding the film contained in a magazine, in the case of a film contained in a general cartridge, it may be wound up by rotating the spool shaft. In this way, the film can be wound at regular intervals without using a sprocket, and the camera can be made smaller. Further, the rotational drive source for the winding shaft is not limited to an electric motor such as a pulse motor, but may also be a spring-type motor or a manual drive. In this case, an electromagnetic clutch may be inserted into the power transmission system and controlled in order to terminate the rotation at a predetermined rotation angle.

As explained above, according to the present invention, the amount of film winding can be changed according to the number of frames to be photographed, so the frame interval of the film is always constant, and unnecessary unused portions between the film frames are eliminated. This makes it possible to photograph more frames than before even with the same length of film.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of one embodiment of a film winding device according to the present invention, and FIG. 2 is an explanatory diagram of another embodiment. 10... Release switch, 12... Counter, 14... Shutter control circuit, 16... Read only memory, 18... Driver circuit, 20...
Pulse motor, 24...Film winding shaft, 26
... Worm gear, 28 ... Worm wheel,
30...nail, 34...film.

Claims (1)

[Claims] 1. In a camera film winding device that winds a film by rotating a film winding shaft,
a counter means for detecting the number of photographed frames; and a counter means for storing rotation angle data of the film winding shaft for each number of photographed frames, the rotation angle of the film winding shaft being set such that the rotation angle of the film winding shaft decreases as the number of photographed frames increases; A film winding device comprising a storage means for outputting rotation angle data addressed by an output of a counter means, and a drive means for driving a film winding shaft in accordance with the rotation angle data output from the storage means.