JPH0545720A - Camera - Google Patents

Abstract

PURPOSE:To prevent a film from being twisted or broken when the film is fed and to prevent the flatness of the film from being deteriorated when the film is pressed with a roller member by providing for the roller member a peripheral surface part which can contact with the film and a non-contact part, and making the rotational angle of the tooth of a sprocket coincide with the rotational angle of the non-contact part. CONSTITUTION:This camera is provided with the roller member 3 having the peripheral surface part 3a which is pressed to a film surface to generate high frictional force and the non-press-contact part 3b which is formed in an area in a part of the peripheral surface part and does not contact with the film surface or contacts therewith by low frictional force, and a rotating member 7 which can rotate integrally with the member 3 and is formed to have a 1st rotating range where it rotates in a state where the tooth part 7a engages with the perforation 2a, 2b of the film in the case of feeding one frame of the film and a 2nd rotating range where it rotates in a state where the tooth part does not engage with the perforation. Then, it is constituted so that the rotating position of the non-press-contact part 3b of the member 3 may be within the 1st rotating range of the rotating member 7. Furthermore, a means is provided for completing the feed of the film by fixed length when the non-press-contact part of the member 3 comes to a position corresponding to the film surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera having a sprocket for feeding a film at a fixed length.

[0002]

2. Description of the Related Art In a camera, it is an important condition to feed a film at a constant length in order to make a frame interval accurate. Conventionally used film feed amount detecting means for feeding a fixed length of film are as follows.

(1) A method in which a sprocket having teeth meshing with the perforation of the film is used and the rotation amount of the sprocket accompanying the feeding of the film is detected by a pulse plate or the like.

(2) A method in which a roller member pressed against the film is used and the rotation amount of the roller member accompanying the feeding of the film is detected by a pulse plate or the like.

(3) A method in which the perforation of the film is optically counted by a photoreflector or the like to calculate the feed amount of the film.

The problem of the above-mentioned film feed amount detecting means (1) will be described.

FIG. 17 is a front view showing a main part of a conventional film feed amount detecting means using a sprocket having teeth.

The sprocket S has teeth G that mesh with the perforations P of the film F. When the pitch of the perforation P is L, the root radius of the sprocket S is B, and the tooth depth of the sprocket S is A, the outer diameter of the sprocket S is A + B, but A + B is at least (A + B) ² ≧ B ² + ( It is designed to satisfy the relationship of L / 2) ² . However, since the outer diameter of the sprocket S is 1/2 or more, there is a problem that the sprocket becomes large when a film having a large pitch of the perforations P is used.

Further, in the film feed amount detecting means of the above (2), an error occurs due to a slip between the roller and the film, and since this error is accumulated, a large error occurs. Further, in the film feed amount detection means of the above (3), the photodetector such as a photoreflector and its drive circuit are expensive, which leads to an increase in the cost of the camera and a complicated and expensive control circuit. There is. Further, since the film feed amount cannot be mechanically output, the counter for the number of film frames cannot be mechanical, and a counter using a liquid crystal display or the like must be used, which is expensive. ..

In order to solve the above-mentioned problems, a roller member which receives a rotational driving force as the film is fed by the frictional force pressed against the film surface, and a roller member which can rotate integrally with the roller member are provided. The applicant has proposed in Japanese Patent Application No. 3-106362 a camera having a sprocket having a rotation range in which it engages with the perforation of the film and rotates and a rotation range in which it does not engage. .. With such a structure, the diameter of the sprocket can be freely set. It is especially effective for small objects. As a result, the camera can be downsized.

[0011]

However, in the above-mentioned conventional example, even when the teeth of the sprocket are engaged with the perforations of the film, the roller member and the film surface are in contact with each other to generate a frictional force. Therefore, the rotational angular velocity of the rotational driving force received by the sprocket teeth from the film is different from the rotational angular velocity of the rotational driving force received by the roller member from the film. That is, when the film feeding speed is constant, the roller member tries to rotate at a constant angular velocity, but the sprocket rotates so that the angular velocity of rotation changes depending on the position where the teeth are engaged with the perforations. Will be available. This can be easily understood by considering the figure in which the tip circle of the sprocket and the running position of the film are chords. A sprocket driven at a constant speed in the string direction does not rotate at a constant speed. For the above reasons, a twisting force is generated on the upper and lower sides of the film, which may break the perforation of the film.

Further, in the above-mentioned conventional example, since the roller member always presses the film surface, the roller member is naturally pressed even at the time of photographing, and thus the flatness of the film at the time of photographing is deteriorated. there were.

An object of the present invention is to provide a camera capable of preventing the film from being twisted or torn and the flatness from being deteriorated when the film is fed.

[0014]

A non-pressing pad which is formed on a peripheral surface portion which is pressed against a film surface to generate a high frictional force and a part of the peripheral surface portion and which contacts the film surface without contact or with a low frictional force. And a first rotation range in which the tooth portion is engaged with the perforation of the film to rotate in the one-frame feeding of the film and the tooth portion is perforated. A rotation member having a second rotation range that rotates in a state in which the roller member is not engaged with, and the rotation position of the non-pressure contact portion of the roller member is within the first rotation range of the rotation member. Is configured.

[0015]

According to the above-mentioned means, the roller member, which is pressed against the film surface and receives the rotational driving force due to the feeding of the film due to the frictional force, rotates integrally with the sprocket, and the perforation of the film causes the teeth of the sprocket to rotate. When the gears mesh with each other, the non-pressure contact portions of the roller members are at the same rotation angle. Therefore, it becomes possible to prevent the film from being twisted or torn due to the difference in the rotation angle between the roller member and the sprocket.

[0016]

Embodiment 1 FIG. 1 is a perspective view showing a main part of an embodiment of a camera according to the present invention, and FIG. 2 is an enlarged perspective view of the sprocket shown in FIG.

Reference numeral 1 is a film cartridge, 2 is a film, and 2a and 2b are perforations. In this embodiment, in order to easily understand the features of the present invention, it is assumed that there is only one perforation per length of film. To do. That is, the aperture size is 36 mm
If so, the pitch of one frame is 38 so that the screens do not overlap.
mm. The pitch between the perforations 2a and 2b is also 38 mm. 3 is a circumferential portion 3a capable of contacting the film
It is a roller (roller member) that is provided with a (peripheral surface portion) and a flat surface portion 3b (non-contact portion) that does not come into contact with the film, and that is rotatably arranged on the camera body (not shown).

A first gear 4 is connected to the roller 3 by a shaft 5 so as to rotate integrally with the roller 3. A second gear 6 is rotatably attached to a main body (not shown) and meshes with the first gear 4. A sprocket 7 is fixed to the shaft 8 by a shaft 8 so as to rotate integrally with the roller 3. Reference numeral 7a is a tooth that can be engaged with the perforation of the film, and the peripheral portion 7b has a diameter that does not contact the film surface.

Reference numeral 9 is a disk whose center of rotation is fixed to a shaft 10 and rotates integrally with the roller 3 and the sprocket 7.
Reference numeral 11 is a pulse substrate, which is fixed to the surface of the disk 9. The pulse board 11 has a conducting portion 11a and a non-conducting portion 11b. Numerals 12 and 13 are pulse contacts for detecting the generation of a pulse accompanying the rotation of the pulse board 11 and transmitting it to a control circuit described later to detect the position of the pulse board 11. A pressing roller 15 is rotatably attached to the roller 3 so as to face the roller 3 with the film interposed therebetween. It is provided with a circumferential portion 15a that can contact the film and a flat portion 15b that does not contact the film.

As shown in FIG. 3, the clearance between the circumferential portion 15a of the pressing roller 15 and the circumferential portion 3a of the roller 3 is t ₁ ,
When the thickness of the film is t ₂ , it is configured so that t ₁ <t ₂ . The film can pass through the gap t ₁ , but at that time, the roller 3 is adapted to be given a rotational driving force by a frictional force. Further, the pressing roller 15 is connected to the second gear by the shaft 8 so as to rotate integrally with the second gear 6. In addition, when the first gear 4 makes one revolution, the second gear 6 makes one revolution.

The film cartridge 1 used in this embodiment is the following one proposed in US Pat. No. 4,834,306.

The film passing slit and one end of which is fixed to the supply spool and which is wound around the supply spool are arranged coaxially with the supply spool, and the radial expansion of the outermost circumference of the film is restricted by the restricting portion. A pressing member that prevents the outermost periphery of the film from substantially contacting the inner wall of the film cartridge, and a part of the pressing member is deformed to continuously release the outermost periphery of the film from the radial restriction of the pressing member. A release part and a guide part that guides the part of the film that has been released from the regulation to the film passage slit, and the outer periphery of the film and the pressing member due to expansion of the outermost periphery due to loosening of the film caused by rotation of the supply spool in the film extrusion direction. Make sure there is no slippage,
A driving force in the extrusion direction is applied to the film, so that the film can be extruded from the film cartridge.

The film is fed by being extruded from the inside of the cartridge by a film feeding gear train known in Japanese Patent Laid-Open No. 2-67534 or the like, which will be described later, and thereafter, known means (for example, perforation 2a,
2b is hooked with a nail, or the film is pressed with a roller member, etc.) and wound up on the spool of the camera,
Will be delivered.

The process before the film is wound around the spool of the camera is the state shown in FIG. 3, and when the film is further fed from this state, it enters between the roller 3 and the pressing roller 15. And, as mentioned above,
Due to the frictional force generated due to the relationship of t ₁ <t ₂ , the roller 3 rotates clockwise (clockwise rotation) as the film is fed. When the roller 3 rotates to the right, the teeth 7a of the sprocket 7 come into contact with the surface of the film 2. When the roller 3 rotates to the right, the pressing roller 15 rotates counterclockwise (counterclockwise) due to the meshing of the first gear and the second gear.
This state is shown in FIG.

After that, even if the film 2 is further fed, since the teeth 7a of the sprocket 7 are in contact with the film surface, the roller 3 and the sprocket 7 do not rotate, and the circumferences of the film 2 and the roller 3 are not rotated. The part 3a slips.
As the film 2 is further fed, the perforations 2a come to a position where they can engage with the teeth 7a, and the teeth 7a engage with the perforations 2a as shown in FIG.
After that, since the perforations 2a and the teeth 7a are engaged, the rollers 3 and the sprockets 7 rotate as shown in FIG. 6 as the film is fed. The circumferential portion 3a of the roller 3 contacts the film 2 until the perforations 2a and the teeth 7a of the sprocket are engaged, and the engagement causes the sprocket to rotate. Receives rotational drive force associated with feeding.

At this time, the flat portion 3b of the roller 3 and the flat portion of the pressing roller 15 are arranged so as to face the film 2. Roller 3 and pressing roller 15
Is in a non-contact state with the film 2, and the roller 3 and the pressing roller 15 are in a state in which the flatness of the film 2 is not adversely affected. Further, since the roller 3 does not receive the rotational driving force and the teeth of the sprocket engage with the perforations to receive only the driving force due to this, the film is not twisted or torn. At this time, the pulse board 11 and the pulse contact pieces 12 and 13 are arranged so that the contact pieces 12 and 13 are switched from the conductive portion 11a of the pulse board 11 to the non-conductive portion 11b.

The control circuit, which will be described later, detects that the pulse contact piece 12 and the pulse contact piece 13 are switched from the conductive state to the non-conductive state, whereby the film feeding motor described later is stopped. Then, as will be described later, a photographing operation is performed at the position of the film 2, and then the film 2 is fed at a fixed length.

Then, the film 2 is fed again from this state. The perforation 2 shown in FIG.
a until the position where the engagement between a and the tooth 7a is released, the circumferential portion 3a of the roller 3 and the circumferential portion 1 of the pressing roller 15 are pressed.
5a is arranged so as to come into contact with the film surface. Then, the sprocket 7 and the film 2 are positioned and rotated until the position where the engagement between the perforations 2a and the teeth 7a is released, but after the engagement is released, the above-mentioned t ₁ < The roller 3 is rotated by the frictional force generated due to the relationship of t ₂ . Laura 3
Assuming that the diameter of the circumferential portion 3b of D is D, the configuration is such that D × π <L is satisfied.
Before b comes into a position where it can be engaged with 7a, the sprocket 7
Rotates until the teeth 7a come into contact with the film surface. This state is shown in FIG. Even if the film is fed until the next perforation 2b comes, the roller 3 only slips on the film surface, and the roller 3 and the sprocket 7 do not rotate.

Even if the roller 3 has a slight slip on the film surface until the state shown in FIGS. 7 to 8 does not completely match the amount of rotation of the roller 3 and the amount of shipping of the film, the diameter D of the roller 3 If is set to be sufficiently smaller than L / π,
The teeth 7a come into contact with the film surface before the next perforation comes. Then, since the next perforation engages with the teeth 7a and the perforations of the sprocket 7 and the film are repositioned, the rotation error of the roller 3 is not accumulated.

FIGS. 9, 10 and 11 are a perspective view and a plan view showing the details of the film feeding gear train used in this embodiment.

In these figures, reference numeral 51 is a film driving motor, which is normally rotated when the film is wound (see FIG. 10).
Arrow B direction), and reverses when the film is rewound (Fig. 11).
Arrow C direction). 52 is a pinion gear fixed to the rotation shaft of the motor 51. Reference numeral 53 denotes a first sun gear, which meshes with the pinion gear 52. 54 is a first planetary gear that meshes with the first sun gear 53.

Reference numeral 55 connects the first sun gear 53 and the first planetary gear 54 to allow the first planetary gear 54 to rotate while generating a frictional force between the first sun gear 53 and the first planetary gear 54. The first sun gear 53 is held and rotated to
Is a first connecting lever which revolves around the first sun gear 53 as a rotation center. The first sun gear 53, the first planetary gear 54, and the first connecting lever 55 constitute a known planetary gear mechanism.

Reference numeral 56 is a spool gear that meshes with the first planetary gear 54 only when the film driving motor 51 rotates in the normal direction. Reference numeral 57 is a film winding spool which is fixed to the spool gear 56 and moves integrally. Reference numeral 58 designates a first idler gear which always meshes with the first sun gear 53,
59 has a large gear 59a and a small gear 59b, and has a large gear portion 5
Reference numeral 9a denotes a first two-stage gear that meshes with the first idler gear 58, and reference numeral 60 denotes a small gear 59b of the first two-stage gear 59.
The second idler gear meshes with the second idler gear 61, and the third idler gear 61 meshes with the second idler gear 60.

Reference numeral 62 is a second sun gear that meshes with the third idler gear 61, and 63 is a second planetary gear that meshes with the second sun gear 62. Reference numeral 64 denotes a third planetary gear, which, like the second planetary gear 63, meshes with the second sun gear. 65 is the second sun gear 62 and the second
Of the planetary gear 63 and the third planetary gear 64 of the arm portion 65a,
65b are connected to each other to rotatably hold the planetary gears while generating frictional force, and the rotation of the second sun gear 62 causes the second planetary gear 63 and the third planetary gear 64 to rotate. The second connecting lever is configured to revolve around the gear 62 as a rotation center. The second sun gear 62, the second and third planetary gears 63 and 64, and the second connecting lever 65 constitute a known planetary gear mechanism.

Reference numeral 66 is a fourth idler gear, which is a second idler gear when the film drive motor 51 is normally rotated.
When the motor 51 rotates in the reverse direction, the second connecting lever 65 rotates to the right when the motor 51 rotates in the reverse direction about the sun gear 62 and rotates to the left to mesh with the second planet gear 63 and not to mesh with the third planet gear 64. Is a gear that meshes with the third planetary gear 64 and does not mesh with the second planetary gear 63.

Reference numeral 67 has a large gear 67a and a small gear 67b, and the second large gear 67a meshes with the fourth idler 66.
, 68 is a third gear having a large gear 68a and a small gear 68b, a large gear portion 68a meshing with the small gear 67b of the second double gear 67, and 69 is the first gear. It is a fork gear that meshes with the small gear 68b of the third two-stage gear 68. Reference numeral 70 denotes a fork that rotates integrally with the fork gear 69, which causes a supply spool (not shown) in the film cartridge 1 to rotate, so that the film 2 is pushed out and wound into the cartridge 1. 7
Reference numeral 1 is a stopper provided on the camera body (not shown)
Is a stopper for regulating the position of the connecting lever 55 in the left rotation direction.

In the above structure, after the film cartridge 1 is loaded in the cartridge chamber (not shown), FIG.
As shown in, the film drive motor 51 (pinion gear 5
When 2) rotates in the direction of arrow B (that is, normal rotation), the first
The sun gear 53 of the
By the action of the connecting lever 55, the first planetary gear 54 revolves clockwise around the first sun gear 53 as a center of rotation, and then meshes with the spool gear 56, so that the driving force of the film driving motor 51 is applied to the spool gear 56. As a result, the film take-up spool 57 rotates clockwise.

The driving force of the second sun gear 53 is the first two-stage gear 59 and the second idler gear 6 via the idler gear 58 which is another gear meshing with the first sun gear 53.
0 and the third idler gear 61 are sequentially transmitted to the second sun gear 62. Therefore, since the second sun gear 62 rotates counterclockwise, the action of the second connecting lever 65 causes the second planet gear 63 and the third planet gear 64 to rotate counterclockwise about the second sun gear. After revolving clockwise, the second planetary gear 63 comes into mesh with the fourth idler gear 66. As a result, the driving force in the B direction of the film driving motor 51 is transmitted to the fourth idler gear 66 as a counterclockwise driving force, and further via the second two-stage gear 67 and the third two-stage gear 68. Fork gear 69
Then, the fork 70 rotates clockwise.

Here, the gear ratio of the gear train is constructed as follows. Set the peripheral speed of the film take-up spool 57 to V
1. If the speed of the film 2 extruded from the film cartridge 1 by the fork 70 is V2, V1> V2
Have a relationship.

When the film 2 is extruded from the film cartridge 1 by the clockwise rotation of the fork 70, the leading end of the film is a known means (a means for hooking the perforation of the film 2 by a claw provided on the film take-up spool 57). Finally, the leader portion at the leading end of the film 2 is finally wound around the film spool 57 by means of pressing the film 2 on the main body side against the film winding spool 57). After that, the winding operation of the film 2 is performed only by the rotation of the film spool 57 by the motor 51, for the reason described below.

When the film is wound around the film spool due to the relationship of V1> V2, the film spool 7 causes the film 2 to pass through the fork gear 69, the third two-stage gear 68, the second two-stage gear 67, and the second gear 67. In the procedure of the fourth idler gear 66, the counterclockwise rotation speed of the fourth idler gear 66 becomes faster than the clockwise rotation speed of the second planetary gear 63.
Causes the second planetary gear 63 to bounce off and the second planetary gear 6
The meshing between the third idler gear 66 and the third idler gear 66 is released for a moment, and the speed difference is absorbed.

Next, the operation of rewinding the film will be described with reference to FIG.

When the film driving motor 51 is rotated in the direction of arrow C, the first linkage lever 55 and the first planetary gear 54 are connected in the counterclockwise direction about the first sun gear 53 as the center of rotation to make the first connection. The end portion 55a of the lever 55 is the stopper 71.
Revolves until it touches. Therefore, the first planetary gear 54
And the spool gear 56 is disengaged.

At this time, the second sun gear 62 rotates in the clockwise direction, so that the second planetary gear 63 and the third planetary gear 64 are actuated by the second connecting lever 65.
The sun gear 62 revolves clockwise around the center of rotation, the meshing of the fourth idler gear 66 and the second planetary gear 63 is released, and the fourth idler gear 66 and the third planetary gear 64 mesh instead. Therefore, the fork gear 69
Rotates counterclockwise, and the supply spool (not shown) in the film cartridge 13 reversely rotates by the fork 70,
The film 2 is rolled into the cartridge 1.

FIG. 12 is a block diagram of the electric circuit of this embodiment.

Reference numeral 100 denotes a control circuit for controlling the entire camera. Reference numeral 101 denotes an AF / AE control circuit including means for measuring a distance to a copy body, which performs an opening / closing operation of a shutter for controlling exposure to a film according to a focusing operation of a photographing lens (not shown) and brightness of the copy body, Reference numeral 102 denotes a film feeding control circuit that controls the rotation of the film feeding motor 1 that is a drive source that feeds the film, and 103 denotes a release switch, which is manually turned on to start the release of the camera. 104 is turned on when a film cartridge is loaded in a cartridge chamber (not shown)
Switch. A switch 105 is turned on by closing a cartridge lid (not shown).

FIG. 13 is a flowchart of the sequence of the control circuit 100. The operation of the camera will be described with reference to this flowchart.

First, when a film cartridge is loaded in a cartridge chamber (not shown) of the camera and the cartridge lid (not shown) is closed, both switches 104 and 105 are turned on, and it is determined that the cartridge is loaded in the camera ( S201). Then, a winding start signal is sent to the film feeding control circuit 102. As a result, the film feeding motor 51 rotates in the direction of arrow B as shown in FIG. 10, and the extrusion of the film 2 from the film cartridge 1 is started via the gear train as described above (S).
202).

Further, as the film is fed after the leading end of the film has passed through the roller 3, the roller and the sprocket 7 rotate as described above. The film feed amount is calculated by detecting 12 and 13. Then, the number of times the contact pieces 12 and 13 change the contact state from the conducting portion 11a of the pulse substrate 11 to the non-conducting portion 11b is counted, and when it reaches a predetermined number, the first frame is cued (S203). To judge.

When the contact between the contact pieces 12 and 13 is switched from the conducting portion 11a of the pulse substrate 11 to the non-conducting portion 11b, the state of the flat portion 3b of the roller 3 and the pressing roller 15 is shown in FIG. Since the flat surface portion 15b is located at a position facing the film, the roller 3 and the pressing roller 15 do not contact the film and do not adversely affect the flatness of the film. Then, the driving of the film feeding motor 51 is stopped through the film feeding control circuit 66 to stop the film winding (S204). Further, it is determined whether or not the release switch 103 is turned on by the photographer (S205), and if it is turned on, the process proceeds to the next process.

Next, the AF / AE control circuit 101 is moved to calculate the brightness of the subject and information on the distance to the subject, and after focusing the photographing lens (not shown), the shutter is controlled to control the film 2 An image capturing operation such as an exposure operation to is performed (S206). Then, the number of releases and the amount of film feed are compared with the number of film frames of the film cartridge 1 read by a known means or a preset number of film frames to determine whether there are remaining frames. It is determined (S207). If there are remaining pieces, step 20
8 and if there is none, the process proceeds to step 211.

If there are remaining frames, the film feeding control circuit 102 is driven to start winding the next frame (S20).
8). Then, the pulse substrate 11 accompanying the feeding of the film 2
It is calculated whether or not one frame of the film 2 has been wound up by the rotation of (S209). That is, again the contact piece 12
When the contact between the pulse contact piece 13 and the pulse contact piece 13 is switched from the conducting portion 11a of the pulse substrate 11 to the non-conducting portion 11b, one frame of film is fed as described above.
When it is detected that one frame of the film 2 has been wound up, the drive of the film feeding motor 51 is immediately stopped through the film feeding control circuit 66 (S210), and the film winding is stopped. This state is the above-mentioned step 204.
6, the flat portion 3b of the roller 3 and the flat portion 15b of the pressing roller 15 are positioned to face the film, so that the roller 3 and the pressing roller 15 contact the film 2 as shown in FIG. It does not have any adverse effect on the flatness of the film.

On the other hand, when there is no remaining frame, the film feeding motor 51 is moved in the film rewinding direction via the film feeding control circuit 102 in order to start the film rewinding, that is, the winding into the film cartridge 1. To drive. After that, the film 2 is rewound into the film cartridge 1, and a known means (for example, a signal from an input means (not shown) at the user's discretion) indicates that the film 2 has been rewound into the film cartridge 1. The input is detected, or the predetermined time for rewinding the film is detected, and the rewinding is completed (S20).
2). Then, via the film feeding control circuit 102,
The driving of the film feeding motor 51 is stopped (S213), and the operation of the entire camera is stopped.

[0054]

[Embodiment 2] FIG. 14 is a perspective view of a sprawl portion showing a second embodiment of the present invention. The present embodiment is different from the configuration of FIG. 2 in a roller 70 and a pressing roller 71, which are first rotation range surfaces 70a and 71a having a first friction coefficient and a second rotation surface smaller than the first friction coefficient, respectively. It has a second rotation range surface 70b, 71b having a friction coefficient of.

Such a structure can be realized by the difference in surface treatment such that the first rotation range surface is a satin surface and the second rotation range surface is a glossy surface. The first rotation range surfaces 70a and 71a correspond to the circumferential portions 3a and 15a of the first embodiment, and the second rotation range surfaces 70b and 71a.
b corresponds to the flat portions 3b and 15b of the first embodiment,
The effect is exactly the same as that of the above embodiment.

[0056]

[Embodiment 3] FIG. 15 is a perspective view of a sprawl portion showing a third embodiment of the present invention. The present embodiment is different from the configuration of FIG. 14 in a roller 80 and a pressing roller 82, and sheets 81 and 83 having a large friction coefficient such as rubber are provided in a portion corresponding to the first rotation range surface in FIG. It has a bonded structure.

[0057]

[Fourth Embodiment] FIG. 16 is a plan view of a sprawl portion showing a fourth embodiment of the present invention. In this embodiment, instead of using the pressing roller 15, the gap t ₄ between the film running rail surface 16a provided on the camera body 16 and the circumferential portion 3a of the roller 3 is set to be t ₄ <t _2. A frictional force is generated between the film surface and the circumferential portion 3a, and a rotational driving force is applied to the roller 3 as the film 2 is fed. Escape groove 1 of film 2 on rail surface 16a
6b is provided.

[0058]

As described above, according to the present invention, the peripheral surface portion which is pressed against the film surface to generate a high frictional force and a part of the peripheral surface portion are formed so as to have no contact or low friction with the film surface. A roller member having a non-pressing portion that contacts with force,
A first rotation range in which the teeth are engaged with the perforations of the film and rotate in the one-frame feeding of the film, which is rotatable integrally with the roller member, and rotates in a state where the teeth are not engaged with the perforations. And a rotation member having a shape having a second rotation range, and the rotation position of the non-pressure contact portion of the roller member is within the first rotation range of the rotation member. It is possible to prevent the film from being twisted or broken due to a difference in rotation angle between the member and the rotating member, that is, the sprocket.

Further, since the constant length feeding of the film is completed when the non-pressure contact portion of the roller member comes to the position corresponding to the film surface, deterioration of the flatness of the film surface due to the pressure contact of the roller member is prevented. You can

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of an embodiment of a camera according to the present invention.

FIG. 2 is an enlarged perspective view of the sprocket shown in FIG.

FIG. 3 is an explanatory diagram showing a process before the film is wound around the spool of the camera.

FIG. 4 is an explanatory diagram showing a process in which a film is fed by pressure contact between a roller and a pressing roller.

FIG. 5 is a plan view of a roller and a pressing roller showing an engagement state between a sprocket tooth and a perforation.

FIG. 6 is a plan view of a roller and a pressing roller showing a state in which the roller and the sprocket rotate with the feeding of the film.

FIG. 7 is a plan view of a roller and a pressing roller showing a state in which the engagement between the perforations and the teeth of the sprocket is released.

FIG. 8 is a plan view of a roller and a pressing roller showing a state in which the sprocket 7 is rotated until it comes into contact with the tooth film surface.

FIG. 9 is a perspective view showing details of a film feeding gear train used in an embodiment of the present invention.

FIG. 10 is a plan view showing an operating state of the film feeding gear train in FIG. 9 during winding.

11 is a plan view showing an operating state of the film feeding gear train in FIG. 9 at the time of rewinding.

FIG. 12 is a block diagram of an electric circuit according to an embodiment of the present invention.

FIG. 13 is a flowchart showing a sequence of a control circuit.

FIG. 14 is a perspective view of a sprawl portion showing a second embodiment of the present invention.

FIG. 15 is a perspective view of a sprawl portion showing a third embodiment of the present invention.

FIG. 16 is a plan view of a sprawl portion showing a fourth embodiment of the present invention.

FIG. 17 is a front view showing a main part of a conventional film feed amount detecting means using a sprocket having teeth.

[Explanation of symbols]

 1 film cartridge 2 film 2a, 2b perforation 3 roller 4 first gear 5 shaft 6 second gear 7 sprocket 7a tooth 7b circumference part 8 shaft 11 pulse board 12, 13 pulse contact piece 15 pressing roller 15a circumference part 15b plane part

Claims (2)

[Claims] 1. A peripheral surface portion which is pressed against the film surface to generate a high frictional force, and a non-pressure contact portion which is formed in a partial region of the peripheral surface portion and is in contact with the film surface without contact or with low frictional force. The roller member, a first rotation range in which the tooth member is rotatable integrally with the roller member and rotates by engaging the tooth portion with the perforation of the film during one frame feeding of the film, and the tooth portion engaging with the perforation. A rotating member having a second rotating range that rotates in a non-rotating state, and the rotational position of the non-pressing portion of the roller member is within the first rotating range of the rotating member. A camera characterized by. 2. The camera according to claim 1, wherein the feeding of the film is stopped within a rotation range where the non-pressing portion of the roller member faces the film surface.