JPH0241729B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a film feed amount detection device that detects the amount of film feed from a counter device, and is particularly suitable for cameras using non-perforated film.

In cameras that have a built-in motor that automatically winds the film one frame at a time, the motor rotates to transport the film after the shutter is activated, and then stops rotating when it detects that one frame has been transported. In addition, considering operability, it is desirable that the motor rotates and winds up to the first frame when the shutter is released after loading the film.

In conventional cameras that use non-porous film, a hole is provided next to the scale on a counter disk, and a light source and a light receiving section that make up a photointerrupter are placed in front of and behind this hole to detect the amount of film feed. This controls the rotation and stopping of the motor. In other words, when the film is loaded and the shutter is released, the motor rotates to transfer the leader section, and when the hole corresponding to the first frame enters between the light source section and the light receiving section, the motor rotation stops. Then, the first frame is placed at the photographing position. When you press the release button to operate the shutter, the motor rotates again and starts transferring one frame, and when the hole corresponding to the second frame enters between the light source and light receiver, the motor stops rotating. , the second frame is placed at the photographing position.

In this device, as the number of frames to be photographed increases, the pitch of the holes becomes smaller, so the size of the holes must be made smaller accordingly. When the hole is made small in this way, there arises a drawback that the identification ability of the light receiving section becomes poor. Although this drawback can be solved by increasing the diameter of the counter disk, it is impossible to realize this due to space constraints.

In view of the above-mentioned drawbacks, the present invention does not impair the identification ability of the light receiving section even if the number of photographed frames is increased, and furthermore, it utilizes a photointerrupter for detecting advance of one frame of the film to detect the empty space at the leading and trailing ends of the film. It is an object of the present invention to provide a film feed amount detection device which can also control the feed.

In order to achieve the above object, the present invention links a counter disc to an indexing disc which rotates in conjunction with film transport through an intermittent feeding mechanism, and also includes:
A light-shielding portion is formed on the counter disc between the first frame and the last frame of the film, and this light-shielding portion overlaps with a hole formed in the indexing disc. Then, the light source part and the light receiving part of the photointerrupter are arranged so as to sandwich the index disk and the light shielding part,
The photointerrupter detects the hole in the indexing disk and controls the drive of the film transport motor.

Embodiments of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, the non-porous film 1 is as follows:
A 120 film or a 220 film is used and is transported in the arrow direction with the backing paper 1a located behind. This transfer is performed by a motor, and as is well known, the motor and the winding shaft are connected, and the winding spool is detachably attached to the winding shaft. The non-porous film 1 is in contact with a length measuring roller 2, and the length measuring roller 2 is rotated when the film is transported in the arrow direction for winding the film. A gear 4 is fixed to the shaft 3 of the length measuring roller 2, and rotates together with the length measuring roller 2 in the direction of the arrow.

The lever 5 rotatably holds a gear 6 that meshes with the gear 4, and is supported by the shaft 3. This lever 5 is formed with a bent piece 5a that is pushed by a protrusion 7a when the back cover 7 is closed, and when pushed by the back cover 7, the lever 5 is bent clockwise about the shaft 3 against the spring 8. , and gear 6 meshes with gear 9.

The gear 9 and index disk 10 are fixed to a shaft 11 and rotate together. This indexing disk 10
has two notches 10a and 10 located 80 degrees apart.
b are formed respectively, and this notch 10
A light source section 12 and a light receiving section 13 are arranged to detect the light beams a and 10b. When the back cover is opened, the index disk 10 is urged by a spring 14 so that one of the notches 10a and 10b enters between the light source section 12 and the light receiving section 13.

As shown in detail in FIG.
has a scale on its surface that indicates the number of frames to be photographed, and a light shielding portion 15a that protrudes in the radial direction is formed between the last frame and the start frame, and this light shielding portion 15a
are arranged in an overlapping state so as to shield the notches 10a and 10b of the index disk 10 from light.

A ratchet gear 16 is provided at the bottom of the counter disc 15, and an intermittent feed pawl 17 meshes with the ratchet gear 16. This intermittent feed pawl 17 is attached to one end of a lever 18, and is biased counterclockwise by a spring 19. The lever 18 has a shaft 20 to which a counter disk 15 and a ratchet gear 16 are fixed.
One end thereof is inserted into the lower surface of the index disk 10, and is pushed by two pins 21a and 21b implanted in the index disk 10. Note that the reference numeral 22 is a check claw.

Next, the operation of the above embodiment will be explained. After loading the non-porous film 1 and closing the back cover 7,
Gear 6 and gear 9 mesh. When the release button is pressed to operate the shutter, the motor rotates to send the backing paper 1a holding the non-perforated film 1 in the direction of the arrow and wind it into the take-up pool. This backing paper 1a
When the length measuring roller 2 is transferred, the length measuring roller 2 rotates, and this rotation is transmitted to the indexing disc 10 via the gears 4 to 9. When the index disk 10 rotates, the lever 18 is pushed by the pin 21a or 21b and rotated by a certain angle, and when the pin 21a or 21b passes, the lever 18 is returned to its original position by the spring 23. Therefore, each time the indexing disk 10 makes a half turn, the lever 18
swings and the intermittent feed pawl 17 moves the ratchet gear 16.
Rotate the ratchet gear 16 by one tooth.
A counter disk 15, which is provided integrally with the counter disk 15, is intermittently rotated.

Between the start piece “S” and the first piece “1”,
Since the light blocking portion 15a is inserted between the light source portion 12 and the light receiving portion 13, even if the cutouts 10a and 10b are inserted between the light source portion 12 and the light receiving portion 13, they will not be detected. As a result, the motor continuously rotates to move the backing paper 1a and the first film to the leading edge of the film.
Transfer pieces. Then, when the number "1" appears in the display window 24, the light shielding part 15a retreats from between the light source part 12 and the light receiving part 13, so when the notch 10a or 10b comes, the light emitted from the light source part 12 is The light reaches the light receiving section 18. When light enters the light receiving section 13, an electrical signal is outputted and sent to the motor control circuit to stop the rotation of the motor. At this time, the first frame of the non-perforated film 1 is placed at the photographing position.

When the release button is pressed, a photograph is taken as usual, and then the motor rotates to transport the non-perforated film 1 and the backing paper 1a. When the index disk 10 rotates half a turn and the notch 10a or 10b is detected by the light receiving section 13, the rotation of the motor is stopped. At this time, the number "2" appears on the display window 24, and the second frame is located at the photographing position.

When the final frame is photographed, the light-shielding part 15a comes over the light-receiving part 13, and the motor continuously rotates to feed the backing paper 1a and wind it onto the take-up spool. When the backing paper 1a is completely wound up, the rotation of the motor is stopped by a switch (not shown) provided on the film transport path.

Further, the counter disc 15 can be opened by opening the back cover 7, similar to the counter zero return structure of a normal camera.
is released from the ratchet gear 16, and is returned to "S" by the force of the spring. At the same time, the gear 6 and the gear 9 are disengaged, and the index disk 10 is moved into the notch 10a or 10 by the force of the spring 14.
b is rotated so that it returns to the predetermined position.

According to the present invention having the above structure, a hole is provided in the index disk which rotates during film transfer, and the hole is detected by a photointerrupter, so that the presence or absence of the hole is detected without being affected by the pitch of the counter disk. can be detected with high accuracy. Also, during the period when the leading and trailing ends of the film are being fed, the photointerrupter is shut off by the light shielding part formed on the counter disk, so each time the photointerrupter passes through the hole in the index disk. The film can be continuously fed without interruption.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG. 2 is a plan view of the counter device. 1... Non-porous film, 1... Backing paper, 2... Length measuring roller, 7... Back cover, 10... Index disc, 10
a, 10b...notch, 12...light source section, 13...
...Light receiving part, 15...Counter disc, 15a...Light shielding part, 17...Intermittent feed claw, 21a, 21b...
pin.

Claims (1)

[Scope of Claims] 1. A length measuring roller that is in contact with the film and rotates as the film is transported, an indexing disc that has at least one hole and rotates in conjunction with the length measuring roller, and an outer periphery. There is a scale indicating the number of frames taken, and the first
A counter disc with a radially protruding light shielding part formed between the pieces and the final piece, and a light source part and a light receiving part sandwiching the passage area of both the light shielding part of the counter disc and the hole of the indexing disc. During the blank feeding period of the leading and trailing ends of the film, the light from the light source part is blocked by the light shielding part of the counter disc, regardless of the passage through the hole of the index disc. A photointerrupter, an intermittent feed mechanism that rotates a counter disk by one pitch each time the index disk rotates by a certain angle determined by the position of the hole, and a film transfer motor that rotates when the shutter operation is completed. . A film feed amount detection device comprising: a motor control circuit for stopping rotation of the motor in response to a signal from the light receiving section detecting light from the light source section. 2. The intermittent feed mechanism includes a pin provided corresponding to the hole in the index disk, a lever pushed by the pin, and an intermittent feed pawl provided at the tip of the lever.
2. The film feed amount detection device according to claim 1, further comprising a ratchet gear provided coaxially with said counter disc and engaged with said intermittent feed pawl.