JPH0119568B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a film feeding method for accurately feeding one frame of film in a camera equipped with an automatic winder mechanism.

Various cameras equipped with automatic winder mechanisms have been known for a long time, but in these conventional cameras, the film feed motor is turned on and off by a switch that is turned on and off each time the film is wound one frame. It was something to control. For this reason, the amount of film fed is not constant due to the influence of battery voltage fluctuations, film fluctuations, motor load fluctuations due to changes in ambient temperature, etc., and the film frame spacing varies.

The present invention has been made in view of this point, and includes a film feeding method in which a film feeding motor is driven and controlled using pulses generated for each unit movement of the film to feed the film. The film feeding speed is determined by the pulse signal from the pulse generating means during feeding, and based on the feeding speed, the amount of film overrun is set when feeding the film frame, and the set overrun amount is used when feeding the film frame. By controlling the drive stop timing of the film feed motor based on the above-mentioned information, the film feed amount, that is, the film frame interval, can be maintained even if there are fluctuations in the output voltage of the battery (power supply), film variations, ambient temperature changes, etc. This is a film feeding method that can feed the film in a constant manner.

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

FIG. 1 is an explanatory diagram showing one embodiment of the method of the present invention, in which 10 is a pulse generator, 20 is a waveform shaping circuit, 30 is a switching circuit, 40 is a one-chip microcomputer (hereinafter abbreviated as MC), 50
is a motor drive circuit, and 60 is a battery.

The pulse generator 10, when winding the film,
It outputs a pulse signal for each unit of movement of the film, and a disc (hereinafter referred to as the "Siemen Star") 11 having a slit in the shape of a Siemens star that rotates in conjunction with film feeding is placed opposite to the Siemens star 11. It is composed of an LED 12 and a phototransistor 13. The Siemenster 11 is a disc in which a large number of slits 11a are radially arranged at equal pitches, and when this disc rotates, it connects the LED 12 to the phototransistor 13.
The beam that is irradiating the area is designed to be intermittent. Note that the output voltage of the battery 60 is applied to the LED 12 and the phototransistor 13 via resistors 12a and 13a, respectively.

The mechanism portion that specifically rotates the Siemens Star 11 is constructed as shown in FIG. That is, a reel 53 is connected to the output shaft of the film feeding motor 51 via a reduction gear train 52, and the film 102 is fed by the rotation of the reel 53, and the sprocket is activated as the film 102 is fed. 101 is rotated, and the rotation is transmitted to gears 103 → 104 → 105 → 106 forming the speed increasing gear train, thereby rotating the Siemens star 11 integrated with gear 106. In addition, 15 is Siemens Star 1
A fixed Siemens star located coaxially with 1. With the above configuration, a pulse signal is output from the phototransistor 13 for each unit movement amount of the film 102.

The waveform shaping circuit 20 is, for example, a Schmitt trigger circuit, and shapes the pulse signal given from the phototransistor 13 into a pulse signal suitable for the MC 40. The switching circuit 30 controls ON/OFF of the power supply to the pulse generator 10 and the waveform shaping circuit 20 based on the control signal from the MC 40, and controls the power supply to the pulse generator 10 and the waveform shaping circuit 20 using the transistor TR.
and resistors R ₁ and R ₂ . The output voltage V of the battery 60 is applied to the emitter of this transistor TR.
is applied, and there is a resistance between the base and emitter.
R ₁ is connected. Furthermore, the base is connected to the output port _O1 of MC40 through a resistor _R2 , and when the signal is LOW, the transistor TR is ON, and conversely, when the signal is HIGH, the transistor TR is ON.
It becomes OFF.

The MC 40 executes a predetermined program, reads pulse signals, and controls various parts, and includes a ROM 42 that stores programs, a RAM 43 that stores data, a central processing unit (hereinafter referred to as CPU) 41 that is the center of control, and a data storage system. I/O port 44 for control input/output,
It consists of a clock oscillator 45 that supplies clock pulses for the CPU 41. In addition, CPU4
1 connects the ROM 42 and RAM 4 via the bus 46.
3 and the I/O port 44 to exchange data and control signals. The I/O port 44 is
Normally, it consists of an input port and an output port, each consisting of a register, a so-called latch, for temporarily storing information, and a decoder for addressing and selecting input/output circuits. The output signal of the waveform shaping circuit 20 is introduced to the input port _I1 , and the output signal of the waveform shaping circuit 20 is input to the output port _O1 .
sends a control signal to the switching circuit 30,
Further, the output port O ₂ sends a control signal to the motor drive circuit 50.

The motor drive circuit 50 includes a film feeding motor 51
The current flowing through the motor 51 is interrupted by a transfer switch 53 of a relay 52. The switch 53 is controlled to turn on and off by energizing the solenoid 54 of the relay 52, and when the switch 53 is turned off, the motor current is cut off and the film feeding motor 51 is braked.

An example of the relationship between the amount of film movement and the speed is shown by curve a in FIG. 3. That is,
When the film feeding motor 51 is energized, the moving speed increases and reaches a constant speed Va at a moving amount _S1 . After that, the film feeding motor 5 is moved at the moving amount Sa.
Even if the drive of the film feed motor 51 is stopped, the film feed motor 51
Due to overrun, it stops at the movement amount Sc.
This amount of overrun is approximately proportional to the speed Va at constant speed. Curve b in FIG. 3 is a characteristic curve when the battery is exhausted or the ambient temperature drops, and the amount of movement S ₂ until reaching constant speed and the speed Vb at constant speed are different from curve a. Therefore, in order to make the film movement amount Sc, for example, it is necessary to stop driving the film feeding motor 51 at a movement amount Sb that is different from the case of curve a. Characteristics also change due to film variations in the same way as described above. However, in either case, the overrun amount has a constant relationship with the speed (Va, Vb) at constant speed. Therefore, MC4
0 stores a correspondence table of film feeding speed and overrun amount for cameras equipped with the MC40.

Next, the operation of the apparatus configured as above will be explained with reference to the flowchart shown in FIG.
In a camera, after loading the film, close the back cover and perform a blank feed (blank copy) of about 3 frames. Therefore, M.C.
40, when confirming that the back cover is closed,
A predetermined number B of pulses generated in the accumulator Acc of the CPU 41 until the film unit speed becomes sufficiently constant (for example, the number of pulses until the movement amount Sk in FIG. 3 is reached is stored in advance in the ROM 42). ). Next, a LOW signal is sent from the output port _O2 to energize the solenoid 54,
Turn on the switch 53 and turn on the film feed motor 5.
Start 1. As a result, the film 102 starts to move, and the pulse generator 10 generates a pulse signal, which is input to the input port _I1 of the MC 40 via the waveform shaping circuit 20. The MC 40 detects the rising edge of this pulse and subtracts 1 from the contents (Acc) of the accumulator Acc. After this subtraction, whether the pulse count number has become B or not, that is (Acc)
It is checked whether or not it has become 0, and if it is 1 or more, the pulses that arrive again are counted. (Acc)=
When it becomes 0, a built-in timer is started, and the rising edge of the next arriving pulse is detected and the timer is stopped. As a result, the pulse interval T at constant speed
(equivalent to the reciprocal of Va and Vb). From this T value, a predicted overrun amount D is determined using the film feeding speed/overrun amount correspondence table in the ROM 42 and is stored in the RAM 43. Next, in order to set the film on the first frame, the film feed motor 5
The number C of pulses remaining until the drive of 1 is stopped is calculated based on the following formula.

C=3A-B-D-1 However, A: The number of pulses required to move one frame.
It is stored in ROM42.

1; Correction value for one uncounted pulse when measuring pulse interval T.

This value C is loaded into the accumulator Acc,
Then, every time a pulse is detected, subtract (Acc) -1
Do the following. At this time, it is determined whether (Acc)=0 or not, and pulse counting is continued until (Acc)=0.
When (Acc)=0, a HIGH signal is output from the output port _O2 , the switch 53 is turned off, and the drive of the film feeding motor 51 is stopped. This results in
After the film feeding motor 51 overruns due to inertia, it completely stops. As the film feeding motor 51 completely stops, the film 102 also stops. Therefore, the first frame of the film 102 is set and the camera enters the standby state. In this standby state, the MC 40 obtains and stores E=A−D. After that, when the relay is done and the shooting of the piece in question is completed, the E
is loaded, and the film feeding motor 51 is driven in the same manner as in the above case. That is, from output port O ₂
Send a LOW signal to energize the solenoid 54,
Turn on the switch 53 and turn on the film feed motor 5.
Start 1. As a result, the movement of the film 102 is started, and a pulse signal is output from the pulse generator 10, and the pulse signal is outputted to the MC 40 via the waveform shaping circuit 20.
is input to input port _I1 . The MC 40 detects the rising edge of this pulse and subtracts 1 from the contents (Acc) of the accumulator Acc. After this subtraction, whether the pulse count has become E, i.e. (Acc)
It is checked whether or not it has become 0, and if it is 1 or more, the pulses that arrive again are counted. (Acc)=
When the value becomes 0, the drive of the film feeding motor 51 is stopped. As a result, the film feeding motor 51 and the film 102 stop after overrunning.
Here, as the film feeding motor 51 completely stops, the stop 102 also stops. The deviation of the stop position of the film 102 from the normal stop position is equal to the deviation of the predicted overrun amount D from the actual overrun amount. By the way, this predicted overrun amount D
is determined from the film feed speed/overrun amount correspondence table (this correspondence table is obtained experimentally) for a certain model of camera, so the above deviation is extremely small. That is, the film 102 stops in a substantially normal state.

Incidentally, in the above embodiment, the configuration is shown in which the period of the output pulse of the pulse generator 10 is sufficiently larger than the period of the clock pulse of the MC 40.
If the period of the output pulse becomes small and is not sufficiently large compared to the period of the clock pulse, the MC40
The pulse generator 10 is equipped with a counter or built-in a counter.
It is also possible to control film feeding using pulses obtained by appropriately frequency-dividing the output pulses.

As explained above, according to the method of the present invention, one frame of film can be fed without being affected by battery voltage fluctuations, variations in various films, motor load fluctuations due to changes in ambient temperature, etc. Therefore, the piece spacing is always constant.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the film feeding method of the present invention, FIG. 2 is a schematic configuration diagram of the Siemens star portion, and FIG. 3 is a characteristic diagram showing the relationship between film movement amount and speed. FIG. 4 is a flowchart for explaining the operation. 10...Pulse generator, 40...Microcomputer, 50...Motor drive circuit, 51...
Film feeding motor.

Claims (1)

[Claims] 1. In a film feeding method in which the film is fed by driving and controlling a film feeding motor using a pulse generated for each unit movement of the film, the film is fed by a pulse signal from a pulse generating means during empty film feeding. Determine the feeding speed, set the amount of film overrun when feeding the film frame based on the feeding speed, and control the drive stop timing of the film feeding motor based on the set overrun amount when feeding the film frame. A film feeding method characterized by: