JPH0574059B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a film abnormality detection device for a projector, which is installed in a projector that forms moving images and detects abnormalities such as film breakage.

[Prior Art] In conventional projectors, images are continuously formed one frame at a time, and a strip-shaped film is attached to both edges of the film, which has holes continuously arranged at equal intervals (so-called perforations). The film is conveyed by rotating a sprocket that engages with the hole, and images formed on each frame are sequentially projected onto a screen. In such a projector, the film may break during transportation, and in some cases, the cut film may become entangled with mechanical members of the projector, causing damage to the projector.

Therefore, conventionally, a film abnormality detection device for a projector has been proposed in which a limit switch is disposed near the bending part of the film formed between adjacent sprockets, and this detects abnormalities such as film breakage. . That is, in a projector, when the sprocket disengages from the holes on both edges of the film due to cutting of the film, the film is no longer conveyed downstream from the sprocket, and the flexed portion formed upstream becomes larger. When the value exceeds a predetermined range, the limit switch of the film abnormality detection device is activated to detect the abnormality.

[Problems to be Solved by the Invention] However, with such a film abnormality detection device for a projector, an abnormality can be detected when the film F is completely cut off as shown in FIG. If the film F is completely cut as shown in the example, an abnormality can be detected, but if the film F is partially broken as shown in FIGS. Since the film F continues to be conveyed by engaging with one of the portions Fc, the size of the bent portion does not change, making it impossible to detect any abnormality in the film.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a film abnormality detecting device for a projector that can detect abnormalities in the film not only when the film is completely cut but also when the film is partially broken.

[Means for Solving the Problems] The present invention, which has been made to achieve the above object, consists of a strip-shaped film in which images are continuously formed one frame at a time, and holes are continuously provided at equal intervals on both edges. A film abnormality detecting device for a projector, which is mounted on a projector that sequentially projects images formed on each frame onto a screen while conveying the film to form a moving image, and detects abnormalities in the film. , a pair of film hole detection means disposed at a predetermined position on the film conveyance path and individually detecting holes on both edges of the film passing through the position; and each film hole detection means sent from the pair of film hole detection means. The present invention provides a film abnormality detecting device for a projector, comprising: determining means for capturing a detection signal as time-series data and determining an abnormality in the film based on the time-series data.

[Function] In the film abnormality detection device of the present invention configured as described above, the pair of film hole detection means disposed at predetermined positions on the film transport path individually detects the holes on both edges of the film passing through the position. Detected.

Since holes are continuously provided at equal intervals on both edges of the film, each detection signal sent from each film hole detection means usually corresponds to the speed at which the film passes through the predetermined position. Therefore, the time series data of each detection signal becomes regular according to a predetermined pattern. However, if an abnormality such as breakage occurs in the film, the above-mentioned time series data becomes irregular.

Therefore, the determination means takes in each of the above detection signals as time series data, and based on the time series data,
Determine film abnormalities.

[Example] Next, embodiments of the present invention will be described with reference to the drawings.

Figure 2 shows a projector 1 of an embodiment to which the present invention is applied.
FIG. This embodiment uses a 35mm movie film on which images are continuously recorded one frame at a time and the corresponding audio is recorded as an optical signal.A moving image is projected and the audio is played back. It is something to do.

As shown in the figure, a xenon lamp 5 is disposed behind the film F held in a convex manner by the film supports 3a and 3b.
Light is irradiated onto the film F held between the projection holes 3c of a and 3b. After the irradiated light passes through the film F, it passes through the lens 7 and converges on a screen (not shown) to project the image recorded on the film F.

In the middle of the optical path from the xenon lamp 5 to the film F, a shutter 9 in the shape of a cone divided into two by a plane including its central axis is disposed.
As shown in the top view of FIG. 3, this shutter 9 is directly connected to a servo motor 13 via a rotating shaft 11, and is rotationally driven to open and close the optical path. Also, as shown in FIG. 3, the film support portion 3b is
The film support portion 3a is biased by a spring 3d to allow the film F to be inserted between the film support portion 3a and the film F to be held therebetween with an appropriate force.

Returning to FIG. 2, the film F has three sprockets (supply sprocket 1
5. It is conveyed downward in the figure by the rotation of the in-tasking sprocket 17 and the take-up sprocket 19). This changes the image projected onto the screen to form a moving image.

That is, an upper reel (not shown) is disposed above the drawing, and the film F wound on the upper reel is
It is guided by the guide roller 21a and conveyed by the supply sprocket 15. Subsequently, the film supports 3a, 3 are guided by the top roller 21b.
After passing through the clamping part b, the intersprocket 17
Transported intermittently by Intasproket 1
7, the film F passes through the guide roller 21c.
and is transported by the take-up sprocket 19. Subsequently, the film F passes through the audio reproduction mechanism 23, passes through the guide roller 21d, and is further adjusted in tension, meandering state, etc. by various guide rollers (not shown), and then is wound onto a winding roller (also not shown). It will be done.

Here, the audio reproduction mechanism 23 is constructed as follows and reproduces the audio recorded on the film F. That is, the film F guided to the upper part of the take-up sprocket 19 by the guide roller 21c passes through the filter roller 23a, and then reaches the sound drum 23.
b, then guided to the lower part of the take-up sprocket 19 through the filter roller 23c, and then conveyed to the guide roller 21d. An optical head (not shown) is disposed near the sound drum 23b, and detects an optical signal recorded on the film F and reproduces it as audio.

On the other hand, supply sprocket 15, in-tasking sprocket 17, and take-up sprocket 1
A servo motor 25, a servo motor 27, and a servo motor 29 are directly connected to the rotating shafts 9, respectively, and rotate each sprocket 15 to 19 individually.

Here, the supply sprocket 15 and the take-up sprocket 19 rotate at a constant speed, but since the inter-sprocket 17 rotates intermittently by one frame of the film F, each sprocket 15 to 1 rotates at a constant speed.
In order to offset the difference in the conveyance amount of the film F due to the supply sprocket 15 and the inter-sprocket 17,
and Fb are provided.

In the projector 1 configured in this manner, when the shutter 9 closes the optical path from the xenon lamp 5 to the film F, the intersprocket 17 is rotated to transport the film F one frame and open the optical path. Sometimes, the interspace processor 17 is stopped and a single still image is projected onto a predetermined position on the screen. By repeating this process, the image projected onto the screen appears to be a moving image.

Furthermore, film hole sensors 31 and 33 for individually detecting the holes Fc formed on both edges of the film F, and an end position sensor 35 for detecting the end of the film F are provided on the transport path of the film F. Film abnormalities such as breakage are detected.

Figure 1 A and B are film hole sensors 31 and 3.
3 and a front view of the film support section 3a in which A.
-A sectional view. However, in A, the interspace sprocket 17 is omitted from the drawing.

As shown in the figure, a fixing member 37 with a groove 37a formed around the periphery is attached to the back surface of the film supporting part 3a, and this fixing member 37 is attached to the projector frame 3.
By inserting it into the mounting hole 39a provided in 9 and engaging the fixing screw 41 and the groove 37a,
A film support portion 3a is fixed to a projector frame 39. Here, a ball portion 41a is fitted to the tip of the fixing screw 41, as shown in FIG. This forms a ball plunger. Therefore, after attaching the fixing screw 41 to the projector frame 39 using the fixing nut 41c, if the fixing member 37 is inserted into the attachment hole 39a against the biasing force of the spring 41b, the groove portion 37a will engage with the ball portion 41a. However, the film support portion 3a can be fixed to the projector frame 39.

Also, returning to FIG. 1 A and B, the film support part 3
The film hole sensors 31 and 33 provided at the lower end of the film F have holes whose tips are connected to both edges of the film F.
A coaxial fiber 43 disposed at a position overlapping with Fc is fixed to the projector frame 39 with a hexagonal nut 45, and the end of the coaxial fiber 43 is
It is connected to a light emitter/receiver 46 composed of a light emitting diode and a phototransistor, and irradiates light onto the film F passing through the tip of the coaxial fiber 43.
This optical sensor detects the hole Fc by converting the reflected light into an electrical signal.

That is, the coaxial fiber 43 is an optical fiber cable in which a light emitting fiber 43a and a light receiving fiber 43b are inserted, as illustrated in the cross-sectional view of the coaxial fiber 43 shown in FIG.
3c is fixed to the lower end of the film support portion 3a. Note that the support member 43c may fix the coaxial fiber 43 at an appropriate location instead of the lower end of the film support portion 3a.

The light constantly generated by the light emitting diode of the light emitting/receiving device 46 is transmitted to the film F via the light emitting fiber 43a.
After being reflected by film F,
The light enters the light receiving fiber 43b, but if the hole Fc of the film F is located at the tip of the coaxial fiber 43, the light emitted from the light emitting fiber 43a passes through the hole Fc and enters the light receiving fiber 43b. is not incident on . Therefore, the presence or absence of reflected light sent through the light-receiving fiber 43b is inputted to the phototransistor of the light projector/receiver 46, and a positive level signal is generated when no reflected light is incident.

On the other hand, as shown in the top view of FIG. 4A, the end position sensor 35 also has a coaxial fiber 47 consisting of a light emitting fiber and a light receiving fiber similar to the coaxial fiber 43, and is constructed in the same manner as the light emitting/receiving device 46. This optical sensor is connected to a light emitter/receiver (not shown) and generates a signal when the end of the film F reaches the film support portion 3a.

Here, the film F has a terminal position sensor 3 when the terminal end thereof reaches the film support portion 3a, for example.
A silver paper Fd is pasted on one edge of the portion being conveyed in the vicinity of 5, as shown in FIG. The reflected light increases, and the light emitter/receiver generates a negative level signal of approximately 30 msec.

Next, pulse generators PG1 to PG3 and pulse generator PG4 are connected to the rotating shafts of the respective servo motors 13 to 29, respectively, and generate pulse signals according to the amount of rotation of each rotating shaft. The drive is controlled by the control system shown in the block diagram of FIG. In addition, each pulse generator PG1, PG2, PG
The number of pulses generated by 3 and PG4 per rotation are 500p.pr, 1000p.pr, 600p.pr, and PG4, respectively.
It is 600p.pr.

As shown in the figure, the projector 1 is composed of a projector main body 1a that projects an image formed on a film F, and a control rack 1b that controls the projector main body 1a. 49 and 51 are provided, respectively.

On the other hand, servo amplifiers 53 to 59 are connected to the servo motors 13 to 29, and each receives a predetermined pulse signal to drive and control the servo motors 13 to 29 individually. Further, pulse signals from pulse generators PG1 to PG4 are inputted to the servo amplifiers 53 to 59, respectively, to form a closed loop, and feed back the amount of rotation of the servo motors 13 to 29.

Furthermore, the control rack 1b is provided with pulse generation circuits 63 to 67 that generate pulse signals based on input from the control circuit 61.The pulse generation circuit 63 is connected to the servo amplifier 53, and the pulse generation circuit 65 is connected to the servo amplifier The amplifier 55 includes a pulse generation circuit 67
is inputting predetermined pulse signals to servo amplifiers 57 and 59, respectively. The control circuit 61 includes a central processing unit (CPU) 61a in which various arithmetic processes are performed, a random access memory (RAM) 61b in which data necessary for each arithmetic process is temporarily read and written, and programs and programs necessary for each arithmetic process. It is composed of a well-known microcomputer whose main part is a read-only memory (ROM) 61c in which data is stored, and a frequency dividing circuit 61c.
Pulse generator PG1 divided by 9
pulse signal, the operation status of the operation panels 49 and 51, and the EMG output from the EMG circuit 71, which will be described later.
A signal is input to instruct the pulse generating circuits 63 to 67 to generate pulses.

Furthermore, the control rack 1b includes a reference signal generation circuit 7.
3 is provided to input a reference signal that serves as a clock for the reference operation of the pulse generating circuits 63 and 67, and output reference signals of 48 Hz and 30 Hz as synchronization signals to external equipment such as a tape recorder (not shown).

Next, the drive control of the servo motors 13 to 29 performed in the projector 1 configured as described above will be explained with reference to the time chart shown in FIG. 6.

When the power switch 49a or 51a is operated to turn on the power, the control circuit 61 starts the pulse generation circuit 6.
3 to oscillate a 24000PPS pulse signal. When this pulse signal is input, the servo amplifier 53 compares the frequency of this pulse signal with the frequency of the pulse sent from the pulse generator PG1, and adjusts the amount of current sent to the servo motor 13 so that the two match. Adjust. Since the number of pulses generated by the pulse generator PG1 is 500 p.pr, the servo motor 13 rotates 48 times per second. That is, the shutter 9 opens and closes 48 times per second.

Next, when the start switch 49b or 51b is operated, the control circuit 61 causes the pulse generation circuit 67 to oscillate a pulse signal of 7200 PPS in synchronization with the second rising edge of the pulse input from the frequency dividing circuit 69. Instruct. Servo amplifiers 57 and 59
When this pulse signal is input, the frequency of this pulse signal and pulse generator PG3 and PG
The frequency of the pulse sent from servo motor 2 is compared with 4 times the frequency of the pulse sent from
Adjust the amount of current sent to 5 and 29. Since the number of pulses generated by pulse generators PG3 and PG4 is 600 p.pr, servo motors 25 and 2
9 rotates 3 times per second.

At the same time, the control circuit 61 also controls the frequency dividing circuit 6.
Every time there is a pulse input from 9, the pulse generation circuit 65 receives a signal in synchronization with the rising edge of the pulse.
The intersprocket 17 is driven intermittently by instructing to oscillate 400 pulses for approximately 8 ms.

The frequency dividing circuit 69 divides the frequency of the pulse generated by the pulse generator PG1 by 500, and thus oscillates one pulse every time the servo motor 13 rotates once.
This pulse corresponds to the opening and closing of shutter 9,
It is used to match the intermittent drive timing of the intersprocket 17 and the opening/closing timing of the shutter 9, and is also output as a 48Hz reference signal to the xenon lamp 5, and is used to match the timing of changing the light amount of the xenon lamp 5 and the opening/closing timing of the shutter 9. Used to match. That is, while the shutter 9 closes the optical path, the xenon lamp 5
This is used to control the amount of light irradiated by half.

In this way, the pulse generating circuit 65 generates a pulse signal of 400 pulses every two revolutions of the servo motor 13. When a pulse signal is input from the pulse generation circuit 65, the servo amplifier 55
compares the number of pulses of this pulse signal with twice the number of pulses sent from pulse generator PG2, and drives the servo motor 13 so that the two match. Since the number of pulses generated by the pulse generator PG2 is 1000 p.pr, the servo motor 27 rotates 1/5. Therefore, the intersprocket 17 also rotates 1/5, which is 4 teeth or 35 mm.
It corresponds to one frame of film F. Incidentally, since the intersprocket 17 is rotated in synchronization with the output signal of the frequency dividing circuit 69, it is performed while the shutter 9 is closed. That is, the film F is conveyed by one frame while the shutter 9 is closed, and stands completely still when the shutter 9 is open, and still images are continuously projected onto the screen.

Next, the EMG circuit 71 provided in the control rack 1b notifies the user of any abnormalities such as breakage of the film F.
When an EMG signal (described in detail later) is input,
Control circuit 61 instructs pulse generating circuits 65 and 67 to interrupt pulse oscillation. As a result, the servo motors 25 to 29 are stopped, and the conveyance of the film F is interrupted.

As shown in the block diagram of FIG. 7, the EMG circuit 71 processes the detection signals of the hole Fc sent from the film hole sensors 31 and 33, and serves as an abnormality determining means for detecting whether or not there is an abnormality in the film. The detection unit 71a and the control circuit 61 when detecting film abnormality.
The EMG output section 71b outputs an MEG signal to the end position sensor 35 and the output control section 71c prohibits the output of the EMG signal based on the output signal from the end position sensor 35 and the operation status of the operation panels 49 and 51. .

The abnormality detection unit 71a includes three AND gates.
AND1 to AND3 (hereinafter simply referred to as AND1 to AND3), each time a pulse signal is input,
Two continuous pulse generation circuits 75 that sequentially generate continuous pulses of a predetermined width from four output terminals S1 to S4.
and 77. In the abnormality detection section 71a, each continuous pulse generation circuit 75
and 77 are film hole sensors 31 and 33, respectively.
The pulses sent from the output terminals S1 to S4 are input, and the pulses generated from the output terminals S1 to S4 are respectively
The outputs are input to AND1 and AND2, and the outputs of AND1 and AND2 are input to AND3.

Next, the detection of film abnormality by the abnormality detecting section 71a will be explained with reference to FIGS. 8 to 10.

FIG. 8 is a time chart showing changes in the signal output from AND1. Note that the signal output by AND2 can be similarly explained.

As mentioned above, Intasproket 17 is 1/24
Since the film F is conveyed by four teeth (that is, four holes) every second (T seconds), the film hole sensor 31 also generates four pulses every T seconds.

The intersprocket 17 starts transporting the film F, and the film hole sensor 31 outputs a pulse P1.
When pulses P2, P3, and P4 are input, the continuous pulse generating circuit 75 generates continuous pulses with a pulse width of T seconds from the output terminal S1. , S4, successive pulses each having a pulse width of T seconds are sequentially generated.
Pulse P4 is input, and continuous pulse generation circuit 75
generates continuous pulses from all output terminals S1 to S4, the output of AND1 becomes High.

After T seconds, when the output from the output terminal S1 changes to Low, the inter-sprocket 17 transports the film F again, so the film hole sensor 3
1, pulses P5 to P8 are input, and the continuous pulse generating circuit 75 again generates continuous pulses each having a pulse width of T seconds from the output terminals S1 to S4. Therefore, the signals generated from output terminals S1 to S4 are always
The high state is maintained, and therefore the output of AND1 is also
Remains High.

Next, AND1 when a film abnormality occurs
The change in the output will be explained by taking as an example the case where two adjacent holes Fc are connected as shown in FIG. 10B. Here, the hole Fc transported by one drive of the intersprocket 17 is
An example will be explained in which the second hole and the third hole are connected.

In FIG. 8, P9 to P12 represent pulse inputs from the film hole sensor 31 at the broken portion of the film F. Since the film F does not exist between the second and third holes of the hole Fc, the film hole sensor 3 is not detected even between the pulse inputs P10 and P11.
The input from 1 becomes High and forms one pulse. Therefore, the continuous pulse generating circuit 75 does not generate a new continuous pulse from the output terminal S3 until the pulse P12 is input, and the continuous pulse generating circuit 75 does not generate a new continuous pulse from the output terminal S3 until the pulse P12 is input.
The output from output terminal S3 in the interval from ~P12 is
Becomes Low. Similarly, since the continuous pulse generation circuit 75 does not generate new continuous pulses from the output terminals S4, S1, and S2 until the pulses P13, P14, and P15 are input, the output from each output terminal is as follows. Pulse input P12-P13, P
13 to P14 and P14 to P15, and therefore the output of AND1 is the pulse input P11.
It becomes Low in the interval from ~P15. Incidentally, since the continuous pulse generated from the output terminal S3 by the pulse input P12 continues until the pulse P16 is input, the signal generated from the output terminal S3 again maintains a constant High state, and similarly. The signals generated from other output terminals S1, S2, and S4 are also always
Becomes High. Therefore, the output of AND1 maintains the High state again after pulse input P15.

In this way, the abnormality detection section 71a detects the film F.
An abnormality such as breakage occurs in the film hole sensor 3.
If the pulse signal sent from 1 or 33 changes irregularly, the output from AND1 or AND2 will change.
Becomes Low. Therefore, the output of AND3, which is the logical product of the outputs of AND1 and AND2, also becomes Low, and a film abnormality is detected.

Returning to FIG. 7, the output control section 71c includes a start switch 49b, a framing switch 49c, and a manual switch 4 provided on the operation panel 49.
9d, the operating states of a start switch 51b, a framing switch 51c, and a reset switch 51e provided on the operation panel 51, and pulses sent from the end position sensor 35 are input.

In the output control section 71c configured in this way, when the start switch 49b or 51b is operated, the EMG output section 71b outputs the EMG signal.
Prohibited for 3.5 seconds, while framing switch 49
When c or 51c is operated, EMG signal output is prohibited for 3 seconds. This is because the rotational speed of each sprocket 15 to 19 becomes unstable at the time of starting and framing, and there is a possibility that the abnormality detecting section 71a may erroneously detect an abnormality in the film.
In the projector 1, when the transport speed of the film F reaches a steady state, a pulse lighting signal is generated that instructs the xenon lamp 5 to turn on.This pulse lighting signal is used to inhibit the output of the EMG signal. May be canceled.

Further, the output control section 71c controls the operation of the projector 1 when the film F is conveyed to the end and the end position sensor 35 detects the silver paper Fd and outputs a negative level signal, and when the manual switch 49d is operated and the projector 1 is driven manually. When switched, the EMG signal output is prohibited, and when the reset switch 51e is operated, the EMG signal output prohibited state of the EMG output section 71b is canceled. At this point, press the reset switch 5.
Even if the start switch 49b or 51b is operated instead of 1e, the inhibition of EMG signal output is canceled after 3.5 seconds as described above.

Subsequently, the EMG output section 71b outputs the abnormality detection section 71.
an abnormality is detected by a, and the output control unit 71
If prohibition of EMG signal output is not instructed by c, or if the
When the EMG switch 51f is operated, an EMG signal is output to the control circuit 61 to control the servo motor 2.
5 to 29 are stopped, and the EMG lamp 51g provided on the operation panel 51 is turned on.

Next, regarding a specific example of film abnormality detection performed in the EMG circuit 71, a specific example of film abnormality shown in FIG. 10 and each sensor 3 shown in FIG.
The explanation will be based on a time chart showing changes in output signals 1 to 35.

If the film F is completely cut upstream of the film hole sensors 31 and 33 as shown in FIG. The output signals output by the sensors 31 and 33 are output from the cut portion as shown in Fig. 9A.
Held in High state. Therefore, the continuous pulse generating circuits 75 and 77 no longer generate new continuous pulses, and the output of AND3 becomes Low. Assuming that the film F has not yet been conveyed to the end, the output of the end position sensor 35 is maintained at a high level. Therefore, the EMG output section 71b is
The EMG lamp 51g is turned on and an EMG signal is output to the control circuit 61 to interrupt the conveyance of the film F.

Next, for example, if two adjacent holes Fc on the side of the film hole sensor 31 are connected as shown in FIG. are connected to form one pulse as shown in FIG. 9B. Therefore, as mentioned above, the output of AND1 is
It becomes Low, and therefore the output of AND3 also becomes Low. Here, assuming that the film F has not yet been conveyed to the end, the output of the end position sensor 35 is
It is held in the High state, and conveyance of film F is similarly interrupted.

Furthermore, even if the film F is longitudinally torn as shown in FIG. 10C or partially broken as shown in FIG. Changes occur as shown, and conveyance of film F is similarly interrupted.

On the other hand, when the film F is conveyed to the end, the ninth
As shown in FIG.
Prohibits the output section 71b from outputting EMG signals.
Therefore, the end of the film F is connected to the film hole sensor 3.
Even if the output signals of the film hole sensors 31 and 33 are held in a high state after the film is transported downstream from the film hole sensors 31 and 33, the EMG signal is not output, so that the film continues to be transported.

In this way, in the projector 1 of this embodiment, the film F
Not only when the film is completely cut, but also when it is partially broken, film abnormality can be detected satisfactorily based on the output signals from the film hole sensors 31 and 33. At this time, based on the output signal from the end position sensor 35, the film F
It is possible to output an EMG signal by distinguishing the case where the film F is broken from the case where the film F is conveyed to the end.

Further, since each of the sensors 31 to 35 is an optical sensor, there is no contact portion with the film F, and there is no fear of damaging the film F.

Furthermore, since the film hole sensors 31 and 33 are disposed between the film support portion 3a and the intersprocket 17, where film abnormalities are most likely to occur, film abnormalities can be detected satisfactorily.

In this embodiment, the film hole sensors 31 and 3
The signal from 3 is input to the EMG circuit 71 to detect film abnormality, but this is directly input to the control circuit 61, the pulses input per predetermined time (for example, T seconds) are counted, and the software Film abnormalities may be detected using a software program, or may be detected using a combination of a software program and an EMG circuit. In this case, by accumulating the counted number of pulses, it is also possible to calculate the number of frames of the transported film at the same time.

Although reflective optical sensors are used for each of the sensors 31 to 35, it is also possible to use transmission optical sensors or ultrasonic sensors. The film hole sensor may be disposed on the outer continuous part of the perforation to detect the connected part, and the end position sensor may be disposed upstream of the film support to directly detect the end of the film. It's okay.

Further, in this embodiment, the shutter 9 continues to drive even when the EMG signal is generated, but the entire control system may be reset to stop all servo motors.

Furthermore, in this embodiment, AND1 and AND2
By taking a logical OR with this, you will get a signal that goes low only when the film is completely cut, and this can be used to determine whether the film has been completely cut or partially broken, and to control the film transport. It is also possible to select a stopping method.

[Effects of the Invention] As described in detail above, the film abnormality detection device for a projector of the present invention detects film abnormalities based on the time series data of the detection signal sent from the film hole detection means, so that the film is not completely damaged. Abnormalities in the film can be detected not only when the film is cut partially, but also when it is partially broken.

[Brief explanation of the drawing]

Figure 1 A is a front view of the film support section in which the film hole sensor is installed, B is a sectional view taken along the line A-A in Figure 1 A, C is a sectional view showing the fixing screw of the film support section, D is the film hole 2 is an explanatory diagram showing the configuration of the projector according to the embodiment; FIG. 3 is a top view schematically illustrating the configuration of the shutter portion; and FIG. 4 A is a cross-sectional view showing the coaxial fiber of the sensor. Figure 5 is a block diagram representing the control system of the projector, Figure 6 is a time chart representing the drive control of the servo motor, and Figure 7 is an EMG diagram. FIGS. 8 and 9 are block diagrams showing the circuit, time charts illustrating the film abnormality detection operation by the EMG circuit, and FIG. 10 is an explanatory diagram showing an example of film breakage. 1... Projector, 3a, 3b... Film support section, 31, 33... Film hole sensor, 61...
Control circuit, 71... EMG circuit, 71a... Abnormality detection section, 71b... EMG output section, 71c... Output control section, F... Film, Fc... Hole section.

Claims (1)

[Claims] 1. Continuously forming images one frame at a time,
A strip-shaped film with continuous holes at equal intervals is attached to both edges, and the film is attached to a projector that sequentially projects images formed on each frame onto a screen while conveying the film to form a moving image. , a film abnormality detecting device for a projector that detects abnormalities in the film, the pair of which are arranged at predetermined positions on the film transport path and individually detect holes on both edges of the film passing through the positions. A film hole detecting means; and a determining means for capturing each detection signal sent from the pair of film hole detecting means as time series data and determining an abnormality in the film based on the time series data. A film abnormality detection device for movie projectors.