JPH07134331A - Film flattening device for camera - Google Patents

Abstract

PURPOSE:To provide a film flattening device improving the flatness of film by providing shafts sliding and turning on the upstream side and the downstream side from the photographic frame of film and applying tension to the photographic frame based on the difference of the revolving speeds of the shafts. CONSTITUTION:An upstream side shaft 20 and a downstream side shaft 22 are disposed on the upstream side and the downstream side of the photographic frame 18a of the film 18 between a cartridge chamber 12 and a spool shaft 14 in a camera, respectively. Rollers 34 and 36 pressing the film 18 to the respective shafts 20 and 22 are disposed behind the shafts 20 and 22, and the shafts 20 and 22 are linked with a driving gear 28 through gear trains 26 and 32. In the case of winding, the spool shaft 14 and the driving gear 28 are turned, and the shafts 20 and 22 slide and turn in the same direction as the spool shaft 14 while the film 18 is moved. Since the revolving speed of the shaft 20 is lower than that of the shaft 22, the tension is applied to the photographic frame 18a positioned between the shafts 20 and 22 and the flatness of the photographic frame 18a is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film flattening device for ensuring the flatness of a film when a camera is exposed.

[0002]

2. Description of the Related Art Popular 35 mm films and brownie films used for cameras are roll films in which a large number of frames are continuously exposed. A camera using this roll film is equipped with a device for winding the roll film frame by frame for convenience of shooting.

For example, in a camera using a 35 mm film, as shown in FIG. 3, a cartridge chamber 2 is formed on one side of the camera body 1 and a spool shaft 3 for winding the film is provided on the other side. Has been. A film rail 5 is provided above and below the aperture 4 along the moving direction of the film, and a pressure plate rail 6 is provided above and below the film rail 5 along the film rail 5. It is provided. As shown in FIGS. 3 and 4, a pressure plate 7 is disposed behind the aperture 4, and the pressure plate 7 is attached to the pressure plate rail 6 from the back cover 8 of the camera body 1 by the pressure spring 7a. Pressed. An appropriate interval is provided between the pressure plate 7 and the film rail 5,
This interval is the tunnel interval.

A film cartridge is housed in the cartridge chamber 2, and the leading end of the film is the spool shaft 3.
Is wound up by. At this time, behind the aperture 4, as shown in FIG. 4, the film 9 passes through the tunnel interval formed by the pressure plate 7 and the film rail 5. Therefore, the tunnel interval is set to be slightly larger than the thickness of the film 9.

[0005]

However, when the film winding device described above is used, since the tunnel spacing is formed slightly larger than the thickness of the film, the film 9 is fixed as shown in FIG. Instead, it becomes a playful state. For this reason, the flatness of the film 9 may not be sufficiently maintained, and the film surface may become a slightly curved curved surface. As a result, at the time of exposure, the image to be formed on the film surface may not be in focus and may be slightly defocused.

On the other hand, if the tunnel interval is formed to be slightly smaller than the thickness of the film, the film is fixed, but the load at the time of winding or rewinding the film becomes large, which may damage the film.

As a means for making the film surface flat, there is known a suction device for sucking the film through a through hole provided at an appropriate position of the pressure plate and bringing the film and the pressure plate into close contact with each other.

However, when this suction device is used, the back cover of the camera body becomes large, which may hinder the reduction in size and weight of the camera. In addition, the manufacturing cost increases, and it is difficult to provide the camera at a low cost.

Therefore, it is an object of the present invention to provide a film flattening device capable of improving the flatness of a film with a simple structure.

[0010]

In order to achieve the above-mentioned object, a film flattening apparatus for a camera according to the present invention comprises:
Tensile means is provided on the upstream side and the downstream side of the filmed frame, and tension is applied to the filmed frame by the tensioning means.
The feature is that the flatness of the photographing frame is ensured.

[0011]

When the roll film is loaded in the camera, the film is wound after the release operation is completed. At this time, the pulling means provided on the upstream side and the downstream side operate while the film is being wound. As a result, tension is applied to the photographic frame after the film has been wound up, and in this state the system waits for the next release.

By applying tension to the film, the flatness of the photographic frame is ensured, and the image of the subject captured by the photographic lens group is focused and formed on the film surface of which the flatness is secured. Image.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A film flattening apparatus for a camera according to the present invention will be specifically described below with reference to the illustrated embodiments. In this embodiment, the film flattening device is
The case where the camera is equipped with a mm film is explained.

As shown in FIG. 1, a cartridge chamber 12 and a spool shaft 14 are provided with an aperture (not shown) located behind the taking lens 10 of the camera body therebetween. The cartridge 16 is housed in the cartridge chamber 12, and the film 18 is pulled out from the cartridge 16. The leading end of the film 18 is wound around the spool shaft 14, and the portion of the film 18 behind the aperture (not shown) is exposed as a photographic frame 18a. Further, a sprocket (not shown) is meshed with an appropriate position of the film 18, and is rotated as the film 18 moves.

Between the cartridge chamber 12 and the spool shaft 14 and on the upstream side of the film frame 18a of the film 18, an upstream shaft 20 is rotatable substantially perpendicularly to the moving direction of the film 18. It is arranged and the above shooting frame 18a
A downstream shaft 22 that is substantially parallel to the upstream shaft 20 is rotatably disposed on the downstream side. A driven gear 24 is fitted on the upstream shaft 20, and the driven gear 24 is linked to a drive gear 28 via an appropriate gear train 26. Further, the driven gear 30 is attached to the downstream shaft 22.
The driven gear 30 is linked to the drive gear 28 through an appropriate gear train 32. The drive gear 28 is linked to, for example, a film feeding motor (not shown) via a gear train (not shown), and the power of the motor is the above-mentioned drive gear.
Transmission from the gear 28 to the driven gears 24 and 30 via the gear trains 26 and 32 causes the upstream shaft 20 and the downstream shaft 22 to rotate. The drive shaft 28, the gear trains 26 and 32, and the driven gears 24 and 30 are set so that the upstream shaft 20 and the downstream shaft 22 are rotated in the same direction. The rotation speed of the side shaft 20 is set smaller than the rotation speed of the downstream shaft 22. It is desirable that a clutch mechanism or the like be interposed in the middle of the power transmission path from the motor to the drive gear 28 so that the power transmission to the drive gear 28 can be interrupted.

An upstream roller 34, which is substantially parallel to the upstream shaft 20, is rotatably disposed behind the upstream shaft 20. The upstream roller 34 is rotatable behind the downstream shaft 22. A downstream roller 36 that is substantially parallel to the shaft 22 is rotatably arranged. The upstream roller 34 and the downstream roller 36 are formed at appropriate intervals in the vertical direction so as to sandwich only the vicinity of the perforation 18b of the film 18, and are attached to a back lid (not shown).
Therefore, when the back cover is closed, the rollers 34 and 36 are pressed by the shafts 20 and 22 which face each other, and when the film 18 is loaded, the film 18 is fed to the upstream roller 34 and the upstream side. It is nipped by the shaft 20 and by the downstream roller 36 and the downstream shaft 22. When the back cover is opened, the rollers 34 and 36 are attached to the shafts 20,
It is separated from 22 and does not interfere with the loading of film 18. The upstream roller 34 and the upstream shaft 20
Further, the downstream roller 36 and the downstream shaft 22 constitute a pulling means.

The operation of the embodiment of the film flattening apparatus according to the present invention constructed as described above will be described below.

When the release operation is completed, a film feeding motor (not shown) operates to rotate the spool shaft 14,
The winding of the film 18 is started. As a result, the film 18 is pulled out from the cartridge 16 and wound up.

When the winding of the film 18 is started, the drive gear 28 is rotated by the operation of a motor (not shown). This rotation is caused by the gear trains 26 and 32 to drive the driven gears 2
4 and 30, the upstream shaft 20 and the downstream shaft 22 rotate. At this time, the film 18 is sandwiched between the upstream shaft 20 and the upstream roller 34, and between the downstream shaft 22 and the downstream roller 36, and the film 18 is wound up by the spool shaft 14. Therefore, the upstream shaft 20 and the downstream shaft 22 rotate while slipping on the surface of the film 18.

At this time, the upstream shaft 20 and the downstream shaft 22 are rotating in the same direction as the spool shaft 14, and depending on the ratio of the set number of gears of the driven gears 24, 30, etc., the upstream shaft 20 The rotational speed of is lower than the rotational speed of the downstream shaft 22. Therefore, tension is applied to the film 18 at the portion between the upstream shaft 20 and the downstream shaft 22, and the flatness of the film 18 located at this portion is ensured.

On the other hand, the sprocket (not shown) is rotated by the movement of the film 18, and the length of the film 18 wound up is detected by this rotation. When it is detected that the film 18 is wound up by one frame, the spool shaft 14 and the drive gear 28 are stopped from rotating, and the film 18 is wound up. At this time, the shooting piece 18a is located in a portion where tension is applied between the upstream shaft 20 and the downstream shaft 22, and the shooting piece 18a is pulled in the longitudinal direction, and its planarity is Reserved.

When exposure is performed in this state, an image of the subject is formed on the surface of the film 18 whose flatness is ensured,
An in-focus image can be obtained. Then, when the exposure is completed, the spool shaft 14 and the drive gear 28 are rotated to wind up the film 18, and the preparation for photographing the next frame is performed.

According to the present embodiment, the rollers 34 and 36 are shaped so as to contact only the vicinity of the perforation 18b of the film 18, so that the rollers 34 and 36 are used for the photographing frame 18
There is no contact with part a. For this reason, film 18
It is possible to obtain a more precise image without damaging the exposed image on the surface of the film or attaching dirt or the like to the film 18.

In this embodiment, while the film 18 is being wound, the upstream shaft 20 and the downstream shaft 22 rotate in the same direction at different rotational speeds to give tension to the photographing frame 18a. , Shooting frames by other rotation methods
It may be a structure that gives tension to 18a.

For example, the downstream shaft 22 and the downstream roller 36 are rotatable without resistance, and the upstream shaft 20 and the upstream roller 34 are rotatable with large resistance. It can be a structure. In this case, when the film 18 is wound up by the spool shaft 14,
The spool shaft 14, the upstream shaft 20, and the upstream roller 34
A tension is applied to the film 18 between the film and the film 18 and the tension is maintained even after the winding is completed.
The flatness of is secured. According to this structure, each shaft
The structure for rotating 20 and 22 is not required, which contributes to downsizing of the camera.

Further, according to this structure, the downstream shaft
22 and the roller 36 on the downstream side can be omitted, and the spool shaft 14 constitutes a pulling means on the downstream side of the photographing frame 18a. As a result, tension is applied to the film 18 between the spool shaft 14 and the upstream shaft 20. That is, since it is not necessary to provide the downstream shaft 22 and the downstream roller 36, the number of parts can be further reduced.

As another example, each of the shafts 20 and 22 is replaced with a roller, and the upstream roller pair and the downstream roller pair are made rotatable by interlocking with each other through an appropriate gear train. The rotational speed of the upstream roller pair is made smaller than the rotational speed of the downstream roller pair, and the rotation of each roller pair is made by the traveling of the film 18 by appropriately adjusting the speed ratio of the. When the film 18 is wound up and the upstream roller pair is rotated by the running of the film 18, the downstream roller pair linked to the upstream roller pair via the gear train rotates at a rotational speed higher than the moving speed of the film 18. Since it moves, the downstream roller pair rotates while slipping in the direction of pulling the film 18 downstream. When the downstream roller pair is rotated by the film 18, the upstream roller pair is rotated by the film 18.
Since the film 18 is rotated at a rotational speed lower than the moving speed thereof, the film 18 is rotated while causing a slip in the direction of pulling the film 18 to the upstream side. Therefore, in any case, tension is applied to the shooting frame 18a, and the flatness is ensured. According to this structure, it is not necessary to provide a device for rotating the upstream roller pair and the downstream roller pair.

Further, as another example, a structure may be provided in which a gear train is provided in which the upstream shaft 20 and the downstream shaft 22 are rotated in opposite directions by the power from the drive gear 28. In this case, after the winding of the film 18 is completed, the drive gear 28 is rotated, and the upstream shaft 20 and the downstream shaft 22 are rotated in opposite directions so as to apply tension to the film 18, and The flatness of the shooting frame 18a located between the shafts 20 and 22 is ensured. According to this structure, since the photographing frame 18a is pulled from the longitudinal direction, the flatness is surely secured.

Further, in the present embodiment, the shape of each of the rollers 34 and 36 is set so as to contact only the vicinity of the perforation 18b of the film 18, but other shapes may be adopted. For example, as shown in FIG. 2, the shape of the upstream roller 38 and the downstream roller 40 may be a shape that covers the entire width of the film 18. According to this structure, tension is applied to the entire film 18 between the upstream shaft 20 and the downstream shaft 22 substantially uniformly, so that the flatness of the photographing frame 18a is further improved.

In the present embodiment, the case where the film is used in a camera in which the film is wound up with photographing has been described. However, it may be used in a so-called prewinding camera in which all the films are wound up immediately after the film is loaded. it can. In this case, the structure and operation when the upstream shaft and the downstream shaft are provided are the same as those in the above-described embodiment, but when the downstream shaft and the downstream roller are omitted, the downstream side is set by the cartridge shaft. Will be constructed. Therefore, the film is tensioned by the cartridge shaft and the upstream shaft.

In this embodiment, the shaft and the roller are used as the pulling means, but other members may be used. For example, instead of the roller, a structure using a sprocket that meshes with the perforation can be used. According to this structure, it is possible to reliably apply tension to the film without causing slippage. Therefore, the flatness of the shooting frame can be further improved.

[0032]

As described above, the film flattening apparatus according to the present invention has a structure in which tensioning means are provided on the upstream side and the downstream side of the filmed frame, and the filmed frame is pulled by the tensioning means. Since the tension is applied from the upstream side and the downstream side of the above, the flatness of the above-mentioned photographing frame is sufficiently secured. Therefore, the image of the subject is surely focused on the film surface, and an image without defocus can be obtained.

Further, since it is not necessary to provide a pressure plate on the back cover of the camera body, the structure of the back cover can be simplified. In particular, since the pressure plate, the pressure plate rail, and the film rail require high precision, the manufacturing cost can be reduced by eliminating these structures.

Further, this film flattening device has a size of 35 mm.
Not only roll films such as films and Brownie films, but also cameras using sheet films can be provided. Therefore, the flatness of the film is ensured in many types of cameras.

[Brief description of drawings]

FIG. 1 is a partially omitted perspective view showing an embodiment of a film flattening apparatus according to the present invention.

FIG. 2 is a partially omitted perspective view showing another embodiment of the film flattening apparatus according to the present invention.

FIG. 3 is a partially omitted front view showing a conventional film winding device.

FIG. 4 is a cross-sectional view taken along the line AA in FIG. 3, showing a positional relationship between a conventional pressure plate and a film.

[Explanation of symbols]

 14 spool shaft (pulling means) 16 film 18a film 18a shooting frame 20 upstream shaft (pulling means) 22 downstream shaft (pulling means) 34 upstream roller (pulling means) 36 downstream roller (pulling means) 38 upstream roller (Pulling means) 40 Downstream roller (Pulling means)

Claims (1)

[Claims] 1. A camera, characterized in that tension means is provided on the upstream side and the downstream side of a film frame to secure the flatness of the film frame by applying tension to the film frame by the tension means. Film flattening device.