JPH0463382B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a film transport device for a camera into which a film having a light-shielding portion can be loaded.

Conventionally, cameras that can load film (for example, size 120 film or 220 film) that has a light-shielding part called a backing paper, or roll holders that can be attached and detached to such cameras are well known (a brief explanation will be given below). (simply with the camera). In the case of such a camera, after loading the film, aligning the start mark printed on the light-shielding part with the desired position on the camera and closing the camera lid, the first frame is loaded manually or via electric means. It is devised so that it can be positioned to the exposure mask. By doing this, it is usually possible to take a required number of frames without wasting film. To make this possible,
The distance from the start mark on the light-shielding part of the film to the beginning of the film is standardized, but due to problems in film manufacturing, this distance may vary, and as a result, the distance from the beginning of the film to the first frame may vary. There were cases where variations occurred in the distance between the two. If this distance is small, the clip holding the film may enter the screen of the first frame during film development, and conversely, if this distance is large, the unexposed area at the end of the film will be small, and the film will be developed in the same way. Sometimes, the above-mentioned clip would enter the screen at the final frame, and in extreme cases, the screen would be cut off, making the final frame unusable.

Also, as described above, after aligning the index on the camera with the start mark in the light-shielding area and closing the back cover of the camera, the film transfer device is driven electrically to move the first frame of the film onto the exposure mask of the camera. After positioning the film at a predetermined position, the film is electrically transferred frame by frame in response to the shutter release operation, and the light-shielded portion at the rear of the film end is transferred to the take-up spool by the shutter release operation after the film is finished. A camera that winds the film repeatedly is also known, but the above-mentioned operational complexity of aligning the start mark and the above-mentioned disadvantages of film positioning remain unsolved.

Therefore, the present invention provides a camera that does not cause the above-mentioned operational complications when loading the camera and problems with positioning the film on the exposure mask, and also provides a camera that completely automates the process from loading the film to winding the film. This is what we are trying to provide.

According to the present invention, the film transport device of the camera is configured such that the camera can use a film having at least a light-shielding portion at both the front end and the rear end, and is further arranged between the film supply spool and the film take-up spool. means for transporting the film so as to pass through the exposed exposure mask; an electric motor for driving the transport means; an edge detection means for detecting the end of the film or the end of the light-shielded portion and generating an electrical signal; Transfer amount detection means detects the transfer amount and generates an electric signal for stopping the motor, and rotates and stops the motor in response to the electric signals from the end detection means and the transfer amount detection means. and a control circuit that controls the film transport means to transfer and stop the film transfer.

Further, according to the present invention, the film transport device for a camera includes, as the above-mentioned edge detection means, a first detection means that changes the level of an electrical output signal when detecting the beginning of the film, and a first detection means for detecting the end of the film. When the level of the electrical output signal changes
and a fourth detection means for detecting the presence or absence of the light-shielding portion to generate an electric signal, and as the film transfer amount detection means, a third detecting means for detecting the amount of film transfer and generating a time-series electric signal. A detection means is provided, and the first and second detection means are provided as the control circuit.
an OR circuit that is activated in response to an input from either the detection means or the counting circuit that counts the signal from the third detection means; the input signal from this OR circuit; the photographing preparation signal; and the fourth detection means. It is constructed of an AND circuit that inputs an electric signal from the detection means.

Hereinafter, the structure and operation of the present invention will be explained in detail based on embodiments shown in the accompanying drawings.

FIG. 1 shows an outline of the mechanism of a film transporting apparatus according to the present invention, and shows a part of the rear part of the camera or a part of a roll holder which can be freely attached to and detached from the rear part of the camera. Hereinafter, for the sake of simplicity, a film transport device integrated with a camera will be described.

In FIG. 1, a film supply spool 2 and a film take-up spool 3, which are well known in so-called medium format cameras, large format cameras, etc., are removably loaded behind an exposure mask 1 provided on a camera body (not shown). The unexposed film F wound around the spool 2 is shielded from light by a light-shielding paper 4 that serves as a light-shielding part to prevent fogging of the film when handling the film during the day. 4 is installed. The starting end FS of the film F is fixedly held on the light-shielding paper 4 via a suitable adhesive piece 5. In FIG. 1, it is assumed that the lower side of the figure is the lens side. In the figure, a guide roller 6 and a film transport amount detecting roller 7 are provided for transporting the film from the film supply spool 2 to the film take-up spool 3 through the exposure mask 1. The rotation of the film transport amount detection roller 7 is transmitted to an index plate 8, and this plate 8 is provided with a signal section 9 for generating a detection signal to the photointerlamp PI. Note that a photoreflector PR1 is located near the film feed amount detection roller 7, and is arranged at a position l relative to the end of the exposure mask 1.
It is arranged so as to detect the position of the film F or the light-shielding paper 4 at a distance of 1.

Further, in the vicinity of the guide roller 6, as is clear from the figure, a photoreflector PR2 is arranged so as to detect the position of the film F or the light-shielding paper 4 at a predetermined distance from the other end of the exposure mask 1. Furthermore, the film take-up spool 3 is driven and rotated by an electric motor, also not shown, via a film transport means, which is a transmission mechanism such as a gear, not shown.

FIG. 2 is a developed view of the film F, and shows an example of a size 120 film. As described above in the figure, the starting end FS of the film F is fixed to the light-shielding paper 4 via the adhesive piece 5, and the conventionally well-known start mark 10 is placed on the light-shielding paper portion in front of the film F.
is printed. The distance between the start mark 10 and the film starting edge FS is L, but as mentioned above, it may vary to some extent. The distance between the film starting edge FS and the desired end of the first frame is assumed to be l1. The distance between the end of the Nth frame determined by the format of the camera used, that is, the exposure mask 1, and the end of the film is l, the distance between the detection position of the photoreflector PR2 and the end of the film is l, and the distance between the detection position of the photoreflector PR2 and the end of the film is α
Then, the end of the final frame of the film (exposure mask 1
The distance between the other end) and the photoreflector PR2 is l.
−α.

FIG. 3 shows an example of a film counter, in which a counter plate 11 is provided with a large number of conventionally known ratchet claws 11a, and numbers are arranged in order to display the number of films that can be checked from outside the camera. . This counter plate 11 is intermittently rotated by a plunger P via a transmission mechanism and an arm 12 (not shown). As is well known in the art, since the counter plate 11 is urged by a spring (not shown) to return to the zero position, check pawls 13 and 14 are provided to prevent the counter plate 11 from reversing.

FIG. 4 shows an embodiment of a control circuit for controlling film transport according to the present invention.
In the figure, the aforementioned photoreflector PR1 consists of a light emitting element 21 and a light receiving element 22, and as the light emitting element 21, an element having a wavelength range outside the photosensitive wavelength range of the film is selected. Photorector PR1
The comparator 23 connected to is set to be at a high level when the film F is not detected, and to be at a low level when the film F is detected, as shown in FIG. 5B. The photoreflector PR2 is also composed of a light emitting element 24 and a light receiving element 25 similar to PR1, and the comparator 26 is set at a high level when the film F is not present, and when the film F is detected, as shown in FIG. It is set to be low level. Further, the aforementioned photointerlamp PI detects the signal portion 9 on the index plate 8 and inputs a pulse signal to the input terminal I of the OR circuit OR and the counting circuit CU via the comparator 27. Photo interrupter PI consists of a light emitting element 28 and a light receiving element 29. The outputs of comparators 23 and 26 are also input to the OR circuit OR.

The output terminal O of the counting circuit CU is connected to the input terminal I of the monostable multivibrator MB and the OR circuit OR, and the output terminal O of the vibrator MB is connected to the R terminal of the flip-flop circuit FP. The other S terminal of the flip-flop circuit FP receives an exposure end signal such as the mirror down signal of a single-lens reflex camera (if the camera is not a single-lens reflex camera, a shutter close signal may be used), and the output of the flip-flop circuit FP is inputted to the other S terminal of the flip-flop circuit FP. is sent to the counting circuit CU as a reset signal from the Q terminal.
input to the reset terminal R of. The OR circuit OR is
Switch SW/C (switch
When SW/C is closed, the switch circuit goes high as shown in Figure 5A) and the film and light-shielding paper presence/absence detection switch SW/F (when switch SW/F is closed, the switch circuit goes high as shown in Figure 5J). (the circuit becomes high level) and is connected to an AND circuit AND. In addition, switch SW/
C is a switch SW/F which is disposed near the film feed amount detection roller 7 and is closed when the back cover is closed and there is a film and light-shielding paper between the roller and the film take-up spool 3. (See Figure 1).

The AND circuit AND is connected to the electric motor M for transporting the film and the plunger P described above. Although not shown in Figure 4, the power supply for the circuit is
The switch SW/C linked to the back cover shall be connected to the circuit so as to put the control circuit into operation when it is closed, but it may also be linked to the pulling out of the cover, as is well known in general cameras. A power switch may be provided separately as shown in FIG.

The flip-flop circuit FP becomes and maintains a high level when an exposure end signal such as the mirror down signal mentioned above is input to the terminal S, and the counting circuit
Reset CU. Also, monostable multivibrator MB (hereinafter referred to as vibrator MB)
generates an output signal when the output of the counting circuit CU becomes low level and outputs the flip-flop circuit.
Inverts the FP output to low level.

In addition, the counting circuit CU is a photo interpolator PI.
When the output signal from the converter 27 connected thereto is low level, the output of the counting circuit CU becomes high level due to the reset signal of the flip-flop circuit FP mentioned above, and provides an input to the OR circuit OR. Furthermore, the counting circuit CU counts the output signal from the comparator 27, and when it reaches a predetermined value, the output changes to low level even if the output of the flip-flop circuit FP is high level and the reset signal is input to the R terminal. It shall be configured as follows.

The operation of the film transport device according to the present invention will be explained below. First, the photographer opens the back cover of the camera (not shown), attaches the film supply spool 2 loaded with unexposed film to the camera, and passes the film through the guide roller 6, exposure mask 1, and film feed amount detection roller 7. The tip of the light-shielding paper 4 is inserted into a groove (not shown) of the film take-up spool 3. In this state, the film presence/absence detection switch SW/F detects the presence of the light-shielding paper 4 and closes, and the back cover opening/closing interlocking switch SW/C also closes (FIG. 5A). At this time, since the photoreflector PR1 also detects the presence of the light-shielding paper 4 (FIG. 5B), the output of the comparator 23 also becomes high level, activating the OR circuit OR (FIG. 5I). Therefore, the AND circuit AND is activated, and the motor M rotates to drive and rotate the light-shielding paper 4 to wind up the film. At this time, the plunger P
is also energized, so rotate the counter plate 11,
"Number 1" is displayed on a display window (not shown). This operation causes the index plate 8 to rotate via the film transport amount detection roller 7, which causes the photo interrupter PI to generate a pulse signal (FIG. 5D), but the reset signal from the flip-flop circuit FP is Since it does not exist, the counting circuit CU does not operate.

When the motor M rotates further and the photoreflector PR1 detects the film starting edge FS, the output of the comparator 23 becomes low level as shown in B in FIG. The input to the OR circuit OR no longer exists, and one of the inputs to the AND circuit AND is cut off, so the motor M stops. This allows the film start FS
The distance 11 between the first frame and one end of the exposure mask 1 is secured, and the first frame of the film correctly occupies a predetermined position on the exposure mask 1 (the state shown in FIG. 1).

Next, when a shutter release button (not shown) is pressed to take a picture and a photographing end signal is generated by the mirror down operation (Fig. 5E), this signal is input to the terminal S of the flip-flop circuit FP, and the counting circuit CU is reset. and becomes ready for counting.
The counting circuit CU becomes high level (state shown in FIG. 5b). As a result, the OR circuit OR operates to rotate the motor M via the AND circuit AND to start film transport. As a result, the photointerrupter PI reads the signal from the rotating index plate 8 and generates a pulse signal (Fig. 5D). When the count value of the counter circuit CU reaches a predetermined value, the counter circuit CU becomes low level, and the motor M stops. Motor M
Since the plunger P is energized at startup, the counter plate 11 rotates and displays the number "2". When the counting circuit CU becomes low level,
The flip-flop circuit FP becomes low level with the output signal from the vibrator MB (Fig. 5H),
The reset state of the counting circuit CU is released. As a result, there is no input to the OR circuit OR, and preparation for photographing the second frame is completed (at the time of FIG. 5C).

By repeating the above operations, the photographing and film transfer up to the Nth frame, which is the lowest frame determined by the camera format, is completed. When the photographing of the Nth frame is completed, a photographing end signal is input by the mirror down, and as mentioned above, the counting circuit CU becomes high level and the motor M (K in Fig. 5) is started.
(Time point d in Figure 5) The film is transferred, but even if the output from the photo interrupter PI and the counting circuit CU disappears (time point f in Figure 5), the photoreflector PR2 detects the end of the film before that. Therefore, the output of the comparator 26 becomes high level, and the motor M continues to rotate. Finally, the end of the light-shielding paper 4 is connected to the film transport amount detection switch SW/F (Fig. 5 J).
opens and one of the inputs to the AND circuit AND no longer exists, so motor M stops rotating. This completes the film transfer, and the film can be taken out at any time.

Note that the position of the photoreflector PR2 is the Nth
When the frame is positioned on exposure mask 1,
As shown in FIG. 2, when the N+1th frame, which is placed at a distance α from the end of the film and does not actually exist, is transferred, the motor M rotates at the above-mentioned timing. You can prevent it from stopping. Further, the distance l between the end of the screen of the Nth frame and the end of the film is shown to be extremely small for convenience of illustration. This is designed to prevent the end of the film from passing through the photoreflector PR2 when the Nth frame of film has been fed.

As described in detail above, according to the film transfer device for a camera according to the present invention, not only can the first frame be accurately positioned by detecting the starting edge of the film, but also the film can be transferred in the middle of the frame and the final edge of the light-shielded portion of the film can be moved. Since the complete winding of the film through detection is performed automatically, the disadvantages mentioned at the beginning of the specification are completely eliminated, making it a cumbersome and unnecessary process not only for professional photographers who are skilled in handling cameras but also for beginners. Therefore, it is possible to reliably load, transport, and take out film without requiring any manual operations, and to provide a camera that is highly satisfactory to all users.

[Brief explanation of the drawing]

FIG. 1 is a top view of a part of a film transport device for a camera according to the present invention, FIG. 2 is a developed view of a film having a well-known light-shielding portion, and FIG. 3 is a schematic diagram of the structure of a counter portion of the camera. FIG. 4 is an explanatory diagram showing an embodiment of the control circuit, and FIG. 5 is an explanatory diagram of the operation of each part of the configuration according to the present invention. 1...Exposure mask, F...Film, FS...
Film starting end, 4... Light shielding part, 7, 8... Film transfer amount detection means, PI... Photo interrupter, PR1, PR2... Photo reflector, CU
...Counting circuit, SW/C, SW/F...Switch,
M...Motor.

Claims (1)

[Claims] 1. In a film transfer device for a camera that can use a film that has light-shielding portions at least at the leading and trailing ends, the film is transported so as to pass through an exposure mask placed between a film supply spool and a film take-up spool. a film transporting means, an electric motor for driving the transporting means, a film end detecting means arranged on the film supply spool side for detecting the film end and generating an electric signal, and a film end detecting means arranged on the film winding spool for detecting the film starting end. film starting edge detection means for detecting and generating an electric signal;
a light shielding part end detection means disposed on the film winding spool side for detecting the end of the film light shielding part and generating an electric signal; and a transport amount detection means for detecting the film transport amount and generating an electric signal to stop the motor. and a control circuit for controlling the motor in response to electrical signals from the detection means and controlling the transfer of the film by the film transfer means.