JPH07270872A - Camera, and method for measuring film feed stopping accuracy and method for measuring perforation detecting accuracy for camera - Google Patents

Abstract

PURPOSE:To accurately detect a braking distance which is so short that it can not be detected by the conventional encoder and to easily perform the measurement of the dispersion of stopping accuracy. CONSTITUTION:Photographic film where a magnetic recording layer is formed is loaded in a camera incorporating a magnetic head. Magnetic recording is performed to recognize the braking time at the time of braking and stopping after feeding the frame of film. The magnetically recorded film is taken out from the camera and carried at fixed speed to reproduce magnetically recorded data. Then, magnetic recording time t1 corresponding to the braking time is measured. Based on the magnetic recording time t1 and the film feeding speed (v) at the time of reproducing, the braking distance d1 of the camera at the time of controlling the stop is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera for magnetically recording photographic information and the like on a magnetic recording layer provided on a photographic film, a film feed stop accuracy measuring method for the camera, and a perforation detection accuracy measuring method.

[0002]

2. Description of the Related Art Exposure control data such as shutter speed and aperture value at the time of shooting, presence or absence of stroboscopic light emission, trimming data set by a user at the time of shooting are magnetically recorded on a film, and these writing data are printed. Attempts have been made to read the data during processing and use it for exposure control and trimming during printing. For example, Japanese Patent Laid-Open No. 5-1
In Japanese Patent No. 65090, in order to write such data during the feeding of the film, the write data is expressed by a binary code of a plurality of bits, and this binary code is expressed by a combination of a magnetized area and a non-magnetized area. , Digital recording is disclosed.

[0003]

On the other hand, in a camera, various methods have been proposed in order to improve the accuracy of stopping the film feeding. However, in order to judge how much the stop accuracy actually varies from frame to frame, if the camera is equipped with an encoder having a high resolution capable of measuring the film moving distance, it is sufficient to monitor the encoder output. Actually, it is difficult to implement an encoder with high resolution due to the demand for cost reduction and size reduction, and it is virtually no exaggeration to know the film moving distance with high accuracy. Also, if you develop after shooting and see the aperture position variation,
Grasping differences such as a few millimeters or less is not realistic and consumes a lot of time and cost.

Further, since the stop control of the film feeding is performed by detecting the perforation, if the perforation length is always detected with the same length and is not recognized, the improvement of the stopping precision of the film feeding is hindered after all. Become. Therefore, it is necessary to know the accuracy of the perforation detection recognition distance. However, due to the above reasons, it is difficult to grasp this with high accuracy.

The present invention has been made in consideration of the above problems, and it is possible to measure a minute distance with high accuracy, which cannot be measured by a conventional encoder, without adding a special circuit. It is an object of the present invention to provide a camera, a film feed stop accuracy measuring method for the camera, and a perforation detection accuracy measuring method.

[0006]

In order to achieve the above object, the present invention provides mode switching means for switching the recording mode of a magnetic head between a normal mode and a test mode,
In the normal mode, magnetic recording is performed during frame feeding of the photographic film, and in the test mode, magnetic recording is performed during braking time during stop control of frame feeding. The stop control of the film is performed when the perforation for frame advance formed on the photographic film is detected. The magnetic recording in the test mode is performed not only for the entire time from the start to the end of the stop braking but also at the start and the end of the stop braking, and the braking time can be obtained based on this. Further, in addition to the magnetic recording for obtaining the stop braking distance, magnetic recording may be performed during the detection of perforation.

[0007]

The stop accuracy is measured as follows. First, a camera having a built-in magnetic head is loaded with a photographic film on which a magnetic recording layer is formed, and magnetic recording is performed so that this braking time can be known at the time of stop braking after frame feeding. next,
Take out this magnetically recorded photo film from the camera,
The magnetic recording is reproduced while being transported at a constant speed. And
The magnetic recording time at this time is measured, and the braking distance of the camera at the time of stop control is obtained based on this magnetic recording time and the film feed speed at the time of reproduction. Therefore, the braking distance, which is difficult to measure with the conventional encoder, is accurately detected. This makes it possible to measure variations in stopping accuracy, and efficiently optimize parameters (including individual difference absorption) of various high-accuracy stopping control techniques. Also, instead of the braking time when the film is stopped, magnetic recording is performed so that the perforation detection distance during frame advance can be known, and this photo film is taken out from the camera and reproduced at a constant speed while reproducing the magnetic recording. The magnetic recording time at this time may be measured, and the perforation detection distance may be obtained based on the magnetic recording time and the film feed speed during reproduction. In this case, the detection and recognition distance of perforation in the camera can be accurately grasped. Therefore, it is possible to measure the variation in the stop accuracy based on the detection accuracy of the perforations.

[0008]

Referring to FIG. 2 showing an embodiment of the present invention, a film feed motor 11 is built in a take-up spool 10, and this motor 11 is driven by a command from a controller 12 equipped with a microcomputer 9. It is driven by the driver 13. The drive transmission mechanism 14 is composed of a gear train, and switches the drive force of the motor 11 between film winding and film rewinding in response to a command from the controller 12. The motor 11 drives the take-up spool 10 so that the film 15 is taken up by the take-up spool 10 when the film winding mode is selected. When the film is rewound, the motor 11 drives the fork 16 so that the film 15 is
Get caught in 7.

The surface of the take-up spool 10 is covered with rubber, and the roller 22 is elastically pressed against this.
The leading end of the film is sandwiched between
By driving 0, the film 15 is securely wound around the spool 10. Incidentally, such a rubber-coated spool 1
Instead of winding the film with 0 and the roller 22,
As is well known, the film may be wound around the spool by a claw that is engaged with perforations formed at the leading end of the film.

Two perforations 15a and 15b per frame are provided on one side edge of the film 15, and a magnetic recording layer 20 is provided on the other side edge.
As for the first frame of the film 15, one more film is provided on the leading end side of the film with respect to the perforation 15a.
Individual perforations 15c are provided. These perforations 15a, 15b, 15c are detected by a reflective photosensor 21. The photoelectric signal from the photo sensor 21 is a perforation signal generator 2
Sent to 3. The perforation signal generator 23 generates a perforation signal PF based on the photoelectric signal and sends it to the controller 12. The controller 12 receives the two perforation signals PF, so that the film 1
The front end of the coil 5 is wound around the spool 10, and it is detected that the first frame is positioned behind the aperture 24 of the camera, and the driving of the motor 11 is stopped. After that, the motor 11 is driven every time photographing is performed, and when the two perforation signals PF are detected, the motor 11 is driven as described later in detail.
Stop driving.

A magnetic head 30 for recording data is provided outside the frame of the aperture 24 so as to be located on a vertical line passing through the photo sensor 21. This magnetic head 3
0 is a writing circuit 31 when the film 15 is advanced one frame.
Driven by a signal from, the photographic information, such as shutter speed and aperture value, is magnetically recorded on the magnetic recording layer 20 by a binary code. For this reason, the microcomputer 9 of the controller 12 stores the information to be magnetically recorded.
The data ROM 32 stored as the decimal code data is connected. The data ROM 32 is composed of an EEPROM.

In the program ROM 33, the motor 1
1 and a sequence for controlling the drive transmission mechanism 14, a sequence program for performing write control in a test mode described later, and the like are stored. RAM34 is
It is used as a work area for temporarily storing the data necessary for performing the shooting sequence and the data writing sequence. The frame number counter 35 counts up by one each time two PF signals are detected after the first frame is set in the aperture 24 to count the number of frames to be photographed.

The controller 12 is also connected to a mode signal generator 26 which outputs a mode signal when the mode selector switch 25 is operated. The mode changeover switch 25 is selectable between a normal recording mode and a test mode. The mode signal generator 26 generates a normal recording mode signal when the mode changeover switch 25 is in the normal recording mode, and sends it to the controller 12. Also, in the test mode, a test mode signal is generated and sent to the controller 12. It is preferable that the mode changeover switch 25 is provided at a special position so that a general user does not operate it by mistake, and the mode changeover cannot be performed by a normal operation. Instead of providing the switch at a special position, a lid may be provided on the switch so that the lid is not opened during normal operation. Furthermore,
The test mode may be switched when the mode switch and the release switch, for example, are simultaneously operated.

FIG. 3 is a timing chart showing frame advance control. The controller 12 drives the motor 11 with the drive voltage V1 based on the frame feed signal after the photographing. As a result, the motor 11 rotates and the film 15 is fed,
When the first perforation 15b is detected after the frame feeding is started, the time from the fall of this perforation signal to the next rise (time for detecting one perforation section) tp is detected. Then, the voltage drop amount Vd for braking is obtained based on this time tp, and the drive voltage of the motor 11 is changed to V2 (= V1-Vd). As a result, deceleration feeding is performed. The deceleration feeding is started when the trailing edge of the second perforation signal is detected after the frame feeding is started. Then, after the driving voltage V2 is decelerated and fed for a predetermined braking time TB, the driving voltage is set to "0" and the motor 11 is stopped.

The voltage drop amount Vd for the section detection time tp for one perforation has been previously obtained by experiments or the like. When this time tp is long, it is determined that the speed is low and the voltage drop amount Vd is reduced. . Further, when the time tp is short, it is determined that the vehicle speed is high, and the voltage drop amount Vd is increased, whereby the brake is activated. In this way, by immediately lowering the drive voltage of the motor 11 immediately before stopping the motor 11, the film feed is braked and the stopping accuracy of the film 15 can be improved. Moreover, since the brake amount is changed according to the film feed speed, the braking distance is made substantially constant for each frame. This further improves the frame feed accuracy. If the braking distance cannot be maintained constant only by changing the drive voltage, the braking time TB may be changed in addition to the change in the drive voltage.

In the normal recording mode, the controller 12 drives the magnetic head 30 at the time of frame feeding after the end of photographing, and the magnetic recording layer 20 is made to correspond to each frame as shown in FIG. 4 (A). The photographing information recording area A1 is recorded.
In the test mode, one frame is sequentially fed to each frame of the film, and the magnetic recording is performed only during the braking time TB at the time of each frame feed in order to inspect the film stop accuracy during the frame feed. I do. As a result, FIG.
As shown in (B), the recording area A2 is recorded on the magnetic recording layer 20 with a length corresponding to the braking time TB of each frame.

FIG. 5 is a schematic view showing a braking distance measuring device for a camera. This braking distance measuring device 39 shows a magnetic recording / reproducing device 44 including a guide roller pair 40, a magnetic reproducing head 41, an amplifier 42, and a capstan 43 in the film feeding direction, and a braking time length of a magnetic reproducing signal from the amplifier 42. It is composed of a measuring device 45 for measuring. The feed roller pair 40, the reproducing head 41, and the capstan 43 are movably provided between a reproducing position shown in the figure and a retracted position separated from the film 15. A pad 46 is provided at a position facing the magnetic reproducing head 41, and the pad 46 presses the magnetic recording layer of the film 15 against the magnetic reproducing head 41 with an appropriate pressing force. A pinch roller 47 is rotatably in contact with the capstan 43.

The signal from the magnetic reproducing head 41 is sent to the amplifier 4
After being amplified by 2, it is sent to the measuring device 45. Measuring instrument 4
5, the signal waveform from the amplifier 42 is displayed on the display 46, and the braking time tb _i (i = 1 to n (n
Is the number of frames per film))). Based on the obtained braking time tb _{i of} each frame and the film feeding speed v of the magnetic recording / reproducing apparatus 44, the braking distance d _i required for stopping the film at the time of frame feeding is calculated by d _i = tb _i × v .

The operation of the camera of the present invention and the method for measuring the braking distance will be described below with reference to FIGS. When the camera 17 is loaded with the cartridge 17 and the back cover is closed, the controller 12 drives the motor 11 to perform the initial feed for setting the first frame of the film 15 in the aperture 24. After that, the mode changeover switch 25 is operated to put the camera in the test mode.

In the test mode, the controller 12 sequentially repeats one frame feed for one film, and drives the magnetic head 30 during the braking time TB during this frame feed to perform magnetic recording for the braking time TB. That is, when the photo sensor 21 detects the first perforation, that is, the rear end side perforation 15b after the frame feed is started, the brake voltage V2 that is the voltage drop amount Vd corresponding to the perforation detection time tp is obtained. Then, the drive voltage of the motor 11 is set via the motor driver 13 so that the brake voltage becomes V2 at the timing of the fall of the perforation signal of the second perforation 15a (tip side perforation) after the frame feeding is started. It is dropped and the brake is applied for a predetermined time TB. Then, the drive of the motor 11 is stopped after a predetermined time TB. Further, during the braking time TB, the magnetic head 30 is driven and magnetic recording is performed, and this magnetic recording is performed until the driving of the motor is stopped. Next, one-frame feeding is performed again, and magnetic recording is similarly performed during the braking time of this one-frame feeding. In the same manner, magnetic recording is similarly performed on all the frames of one film in correspondence with the braking time TB of the motor 11.

When magnetic recording for the braking time TB is completed for all frames, the controller 12 causes the motor 1
1 is reversed and the film 15 is rewound into the cartridge 17 by the fork 16. After that, the back cover of the camera is opened, and the cartridge 17 in which the braking time is magnetically recorded is taken out. When the back cover of the camera is opened, the controller 12 detects this with a sensor (not shown) and automatically switches from the test mode to the normal shooting mode. In this way, by taking out the cartridge 17 in which the braking time is magnetically recorded in the test mode, the test mode is switched to the normal photographing mode, so that the mode switching is not forgotten.

The patrone 17 which has been rewound is taken out from the camera and loaded into the braking distance measuring device 39. When the feeding mechanism (not shown) rotates the spool 50 after loading, the leading end of the film is fed from the cartridge 17 and the film 15 is fed in the direction of the arrow in the figure. When the leading end of the film 15 passes the reproducing head 41 and the capstan 43, the feed roller pair 40, the reproducing head 41, and the pinch roller 43 are set from the retracted position to the reproducing position, and the reproducing head 41 is set on the magnetic recording layer 20 of the film 15. It can be pressed.

As a result, the film 15 is fed at the feeding speed v in the arrow direction. The reproduction signal from the reproduction head 41 is amplified by the amplifier 42 and then sent to the measuring device 45, the reproduction waveform corresponding to the braking time is displayed on the display 46, and the braking time t _i proportional to the braking time on the camera side. Is measured. Then, the braking distance d _i is obtained from the braking time t _i and the film feed speed v. With this braking distance d _i , it is possible to measure the variation in the film stop accuracy, and on the basis of this, it is possible to efficiently optimize the parameters of the high-accuracy stop control technique. Optimization of this parameter also includes absorption of individual differences. The braking distance d _i may be calculated when the measuring device 45 has a calculation function, or may be calculated by using another calculation device.

In the above embodiment, magnetic recording was performed during the braking time, but in addition to this, as shown in FIG. 6, magnetic recording may be performed at the beginning and the end of the braking time TB. Then, the braking time t _i can be obtained.

Further, in the above embodiment, the magnetic recording is performed for the braking time TB to obtain the variation in the film stop accuracy. In addition to this, as shown in FIG. 7, the magnetic recording is performed for the perforation detection time tp _i. Alternatively, in this case, the variation in the detection accuracy of perforations can be efficiently obtained. Therefore,
The circuit constants of the perforation detection circuit can be optimized and individual differences can be absorbed. Also in this case, in addition to magnetic recording in the entire section of the perforation detection time, only the first and last magnetic recordings can be magnetically recorded to inspect variations in perforation detection time.

FIG. 4C shows an example of magnetic recording in this way, and the recording area A3 is recorded on the magnetic recording layer 20 with a length corresponding to the detection time of perforation of each frame. In this embodiment, the magnetic recording is performed only for the first perforation after the frame feeding is started, but it may be magnetically recorded for all the perforations. In addition to separately performing the braking distance measurement and the perforation detection length measurement in this way,
As shown in FIGS. 4 (B) and 4 (C), since the recorded positions are different during these measurements, the braking distance and the perforation detection length should be measured by one film feed. You may

Further, in the above embodiment, the film having two perforations for one frame is used, but the number of perforations may be appropriately changed. For example, it may be carried out by a conventional camera using a 135 type film in which perforations are provided at a ratio of 8 per full size frame. In this case,
When eight perforations are detected, it is regarded as one frame. In addition, the braking of the film feed may be performed by using a brake mechanism in addition to reducing the drive voltage of the motor 11. It should be noted that such a stopping accuracy measuring method can be effectively used not only during technical development but also during production and adjustment and testing after repair. Further, in the above-described embodiment, the film 15 is pulled out from the film cartridge 17 at the time of shooting, and the film 15 is wound into the film cartridge 17 after shooting all frames. It may be carried out in a prewinding type camera which winds up the film on the take-up spool and winds the filmed film one frame at a time in the cartridge after the filming.

[0028]

As described above, according to the present invention,
A mode switching means is provided to switch the recording mode of the magnetic head between the normal mode and the test mode.In the normal mode, magnetic recording is performed during frame feeding of the photo film, and in the test mode during the braking time during stop control of frame feeding. Since the magnetic recording is performed in the above, it is not necessary to provide an encoder or the like having a high resolution, and the braking distance at the stop control at the time of frame feeding can be accurately and efficiently obtained.
Therefore, since the stop braking distance is accurately calculated,
It is possible to efficiently optimize the parameters when stopping the film with high accuracy.

Further, the film magnetically recorded in the test mode is reproduced by a magnetic reproducing device at a constant film feeding speed, and the magnetic recording time at this time is measured. Based on the magnetic recording time and the film feeding speed, Since the braking distance of the camera at the time of stop control is obtained, the braking distance, which is a minute distance that was difficult to measure with the conventional encoder, can be easily realized without requiring special parts or circuits. Therefore, the frame advance accuracy in the camera can be improved. Moreover, since the magnetic recording is used, the measurement can be performed in a bright room unlike the photographing, and the braking distance can be easily measured. Also, the film can be used a plurality of times by degaussing.

Further, even if the film feeding speed of the camera fluctuates, magnetic recording is performed in this fluctuating state, and since only the magnetically recorded distance is measured, it may be affected by voltage fluctuation, friction fluctuation and the like. Without, it is possible to accurately grasp the variation in braking during frame feeding. Further, any magnetic recording distance can be measured, there is no need to magnetically record a special code or the like, and magnetic recording can be performed at a certain cycle, and magnetic recording can be easily performed. Moreover, in this case, since the magnetically recorded distance can be measured, the period may be variable or fixed, and the magnetic recording can be easily performed.

[Brief description of drawings]

FIG. 1 is a flowchart showing a main part of a camera film feed stop accuracy measuring method of the present invention.

FIG. 2 is a schematic view showing a main part of the camera of the present invention.

FIG. 3 is a timing chart showing frame advance control.

FIG. 4A is an explanatory diagram showing an example of a photographic film magnetically recorded in a normal photographing mode, and FIG. 4B is an example of a photographic film magnetically recorded to measure a braking distance in a test mode. FIG. 4C is an explanatory diagram showing an example of a photographic film magnetically recorded for measuring a perforation detection length in a test mode.

FIG. 5 is a schematic view showing a braking distance measuring device for a camera.

FIG. 6 is an explanatory diagram showing an example of a recording waveform in another embodiment in which magnetic recording is performed during braking time.

FIG. 7 is a timing chart in another example in which magnetic recording is performed during perforation detection time.

[Explanation of symbols]

 10 Take-up spool 11 Motor 12 Controller 15 Film 15a, 15b, 15c Perforation 17 Patrone 20 Magnetic recording layer 21 Photosensor 30 Magnetic recording head 39 Braking distance measuring device 41 Magnetic reproducing head 43 Capstan 44 Magnetic recording / reproducing device 45 Measuring instrument

Claims (7)

[Claims] 1. A camera having a built-in magnetic head for magnetic recording on a magnetic recording layer of a photographic film during feeding of the photographic film, comprising mode switching means for switching a recording mode of the magnetic head between a normal mode and a test mode. A camera characterized in that magnetic recording is performed during frame feeding of a photo film in the normal mode, and magnetic recording is performed during braking time during stop control of frame feeding in the test mode. 2. The camera according to claim 1, wherein the stop control of the film is performed when a perforation for ending frame advance formed on a photographic film is detected. 3. The camera according to claim 1, wherein
The camera is characterized in that the magnetic recording in the test mode is performed during the entire time from the start to the end of stop braking. 4. The camera according to claim 1, wherein
The camera is characterized in that the magnetic recording in the test mode is performed only at the start and end of stop braking. 5. The camera according to claim 1, wherein the magnetic recording in the test mode is performed during perforation detection. 6. A camera having a built-in magnetic head is loaded with a photographic film having a magnetic recording layer, and magnetic recording is performed so that the braking time can be known during stop braking after frame feeding, and the magnetically recorded photographic film. Is taken out of the camera, magnetic recording is reproduced while being conveyed at a constant speed, the magnetic recording time at this time is measured, and the braking distance of the camera during stop control is determined based on this magnetic recording time and the constant speed. Characteristic camera film feed stop accuracy measurement method. 7. A camera having a built-in magnetic head is loaded with a photographic film having a magnetic recording layer and a perforation for frame advance, and frame advance control is performed based on the detection of the perforation. The magnetic recording is performed so that the detection distance of the magnetic recording medium can be understood, the magnetic recording is taken out of the camera and the magnetic recording is reproduced while being conveyed at a constant speed, and the magnetic recording time at this time is measured. A perforation detection accuracy measuring method for a camera, which comprises obtaining a perforation detection distance based on a constant speed.