JPS5824124A - Film feeding method - Google Patents

Abstract

PURPOSE:To feed one frame portion exactly, by forecasting an overrun extent of a film in accordance with a feed speed in case of blind exposures executed after loading the film, and stopping a drive of a motor in anticipation of the overrun extent, in a camera provided with an auto winder. CONSTITUTION:A pulse generating device 10 outputs a pulse signal at every unit moving extent of a film when winding the film, and it is shaped 20 for its waveform and is inputted to an MC40. As for a camera, after a film has been loaded, its back cover is closed, and blind exposures are executed by 3 frames or so. As a result, to the MC40, a prescribed number B of pulses generated before a film moving speed becomes a constant speed sufficiently is loaded. Subsequently, a feed motor 51 is started, and a pulse interval T in case of a constant speed is measured. From the interval T, an overrun forecasting extent D is derived by use of an overrun extent correspondence table, and the remaining number C of pulses before driving of the motor 51 is stopped is calculated in accordance with the expression C=3A-B-C-1. In this regard, the number A is the number of pulses required for the movement of 1 frame portion. In this way, a film can be fed against a fluctuation of battery voltage, irregularities of the film, and a variation of ambient temperatures.

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 autowinder mechanism.

Various cameras equipped with automatic winder mechanisms have been known for a long time, but in these conventional cameras, the film feed for each frame is turned on and off each time the film is wound one frame.
The film feed motor was controlled by a switch. For this reason, the film feeding amount 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 is 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. By predicting the film overrun t based on the feeding speed during film empty feeding after loading the film, and stopping the drive of the film feeding motor in anticipation of the amount of overrun when the film is being loaded, the battery ( A completely realized film feeding method that can feed the film so that the film feeding amount, that is, the film frame interval, remains constant even when there are fluctuations in the output voltage of the power source), film variations, and ambient temperature changes. It is.

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

FIG. 7 is an explanatory diagram showing one embodiment of the method of the present invention, where 10 is a pulse generator, 0 is a waveform shaping circuit, 30 is a switching circuit, and 4io is a one-chip microcomputer (
(hereinafter abbreviated as MC),! 0 is a motor drive circuit, and to is a battery.

The pulse generator 10 outputs a pulse signal for each unit movement of the film when winding the film, and is a disk having a Siemens star-shaped slit (hereinafter referred to as Siemens star) that moves and rotates during film feeding. //, an LID/λ, and a phototransistor 13, which are arranged opposite to each other with the Siemens star // in between.

The Siemenster/l is a circular plate provided with a large number of radially spaced rings)//a with equal pitches, and as it rotates, it connects the phototransistor/J from the LID/co.
The beam being irradiated to the area is intermittent. Note that LΣDI2 and phototransistor 13 each have a resistor lja.

The output voltage of the battery 60 is applied via /Ja.

The specific mechanical part that rotates the Siemenster// is as follows:
It is constructed as shown in FIG.

That is, a reel j3 is slow-coupled to the output shaft of the film feeding motor jl via a reduction gear train J, and the rotation of this reel j3 feeds 10 films.
The sprocket lO1 is rotated in accordance with the feeding of the gear 10J→ioa→lQj→
The signal is transmitted to the iot and rotates the nine Siemens stars /, /, which are integrated with the gear 104. Note that lj is a fixed Siemens star arranged coaxially with Siemens star 1/. With the above configuration, a pulse signal is output from the phototransistor 3 for each unit movement amount of the film 102.

The waveform shaping circuit λO is, for example, a Schmitt trigger circuit, and shapes the pulse signal given from the phototransistor J into a pulse signal suitable for the MC. The switching circuit 30 controls ON/OFF of the power supply supplied to the bus generator 10 and the waveform shaping circuit 0 by a control signal from the MC1fiO, and is composed of a transistor TR and resistors R1 and R. .

A battery t is connected to the emitter of this transistor TH.

An output voltage V is applied thereto, and a resistor R1 is connected between the base and the output terminal. Further, the base is connected to the output port 0 of the MCuO through the resistor blade 1, and when the signal is LOW, the transistor TRdON becomes ON, and conversely, when the signal is HIGH, the transistor TB becomes oyy.

MCCOO, which executes a predetermined program and reads pulse signals, controls each part, stores programs in fl-ROM≠2, and stores data in 8mm memory.
, the central processing unit (C
PU), an I10 port for data and control input/output, and a clock oscillator for supplying clock pulses for the CPU. Furthermore, C
The PU reference is connected to ROM≠λ, RAM≠ via bus≠6.
The s10 boat, which exchanges data and control signals with the 3 and 110 boats, usually has a register that temporarily stores information, a so-called latch, and a decoder to address and select input/output circuits. A 0-person capo consisting of a human-powered boat and an output port)
The output signal of the waveform shaping circuit -0 is introduced into It, the output port 01 sends a control signal to the switching circuit 30, and the output port 01 is the motor drive circuit! Sends a control signal to O.

The motor drive circuit j0 drives the film feeding motor jl, and the motor! The current flowing IK is interrupted by transfer switch j3 of relay j2. switch j3
Ha, Relay jko's Nrenoid! FiON・
When the switch j3 is turned off, the motor IEflt is turned off and the film feeding motor j/ is braked.

Here, an example of the relationship between film movement amount and speed is shown by curve a in FIG. 3. That is, when the film feeding motor j/ is energized, the moving speed increases and reaches a constant speed Va at a moving amount 81. After that, the film feeding motor moves with a movement amount of 8a! Even if you stop driving the film feed motor! Due to overrun of 1, it stops at a movement amount of 8e. This overrun amount is the speed at constant speed [Va
is approximately proportional to The curve in FIG. 3 is a characteristic curve when the battery is exhausted and the ambient temperature is lowered, and the amount of movement S1 until reaching constant speed and the speed vb at constant speed are different from those in the case of song IIa. Therefore, for example, if the amount of film movement is 8c
In order to do this, it is necessary to stop the drive of the film feeding motor j/ at a movement amount 8b which is different from that in the case of song @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 at constant speed (V 11 vb ).

Therefore, MCCOO stores a correspondence table of film feed distance and overrun amount for cameras equipped with MO San〇. This will be explained with reference to the flowchart shown in . Load the film in the camera, close the lid and shoot 3 frames! [conduct. Therefore,
MCCOO, after confirming that the camera back is closed,
Accumulator AJ of CPU447 Then, the pLOW signal is sent to the output boat to energize the renoid j≠, and the switch j3 is turned on to start the film feed motor j/f. This starts the movement of the film lOλ and generates a pulse mIl/.

A pulse signal is generated from M through the waveform shaping circuit O.
CCOO person capo) Is is input.

MC1fiO detects the rising edge of this pulse and subtracts /'t- from the content (A-) of the achievator Aea.

This subtraction property, whether the pulse count number has become B or not,
That is, it is checked whether (Ac.) has become 0 or not, and if it is 1 or more, the incoming pulses are counted. (Ac
When ) = 0, it starts a built-in timer, detects the next rising edge of the pulse, and stops the timer.

This measures the pulse interval T (corresponding to the reciprocal of Va and Wb) at constant speed. From this T value, a predicted overrun amount is determined using the film feeding speed/overrun amount correspondence table in the ROM 44 and is stored in RAM≠3. Next, the number of pulses Ct remaining until the film is set in the first frame and the drive of the film feeding motor si is stopped is calculated based on the following formula.

C=Jmu-B-D-/ However, A; RO is set in advance with the number of pulses required for the movement amount of I pieces.
It is stored in M≠λ.

l: Correction value for uncounted l pulses when measuring pulse interval T - This value C is loaded into the accumulator Aac, and then subtracted (Aaa) - / every time a pulse is detected.
At this time, it is determined whether (Aaa)=0 or not, and pulse counting is continued until it becomes ＠e)-0.

When 1 (as) = 0, HIGH from output port 03
A signal is output, switch jJ is turned OFF, and driving of film feeding motor j/ is stopped. As a result, the film feed motor j/ overruns due to inertia and stops completely after the film is removed. With this complete stop of the film feed motor j/, the film lOλ also stops. Therefore, the first frame of the film 10J is set and enters the standby state. In this standby state, MCll0 obtains and stores IC=A-D. Thereafter, the release is performed and the shooting of the coughing frame is completed. Then, accumulator Aa
elCB is loaded and the film feed motor si is driven in the same manner as in the above case. That is, output capo) Ox than b
The ow signal is sent to energize the renoid j≠, and the switch jJt-ON is turned on to start the film feeding motor j/. As a result, the film begins to move (
A pulse signal is output from the pulse generator 10, and is manually inputted to the manual boat X1 where MC≠0 through the waveform shaping circuit 20'ff. MCCOO (this) (Luz's rising yt is detected, l is subtracted from the contents (mul) of the achievator A.@.

After this subtraction, it is checked whether the pulse count becomes E (9), that is, whether (MU0) becomes 0. If it is 1 or more, the pulses that arrive again are counted. (Ag
e) When it becomes -t□, it is the film feeding motor! Stop driving l.

As a result, the film feed motor j/and the film lO
The machine overruns and the press stops. Here, this film feeding motor! With the complete stop of /, the film 10λ also stops. The deviation of the stop position of the film lO from the normal stop position is equal to the deviation of the overrun prediction scale from the actual overrun amount.By the way, this overrun prediction scale is based on the film feed speed of a certain model of camera. Since it is obtained from the overrun amount correspondence table (this table is obtained experimentally), the above deviation is extremely small, that is, the film 10λ stops in a substantially normal state.

In the above embodiment, the period of the output pulse of the pulse generator io is sufficiently larger than the period of the clock pulse A/S of the MC4AO. If it is not sufficiently large compared to the cycle, it is also possible to attach a counter externally or internally to the MC'IO, divide the output pulses of the pulse generator io as appropriate, and use the pulse generator to control film feeding. As explained above, according to the method of the present invention, it is possible to feed one frame of film without being affected by battery voltage fluctuations, various films' (lackiness), motor load fluctuations due to ambient temperature changes, etc. can.

Therefore, the piece spacing is always constant.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment of the film feeding method of the present invention, FIG. 2 is a schematic diagram of a part of the Siemens star, and FIG.
The figure is a characteristic diagram showing the relationship between the amount of film movement and the speed, and the second figure is a four-chart diagram for explaining the operation. 10...Pulse generator ≠O...Microcomputer jO...Motor drive circuit! l...Film feeding motor patent applicant Toji Ijima, patent attorney Roku Konishi Photo Industry Co., Ltd.

Claims (1)

[Claims] In a film feeding method in which the film is fed by driving and controlling the film feeding motor using pulses generated for each unit of film movement, the feeding speed during film feeding after loading the film into the camera. A film feeding method characterized in that the amount of overrun of the film is predicted based on the amount of overrun of the film, and the driving of the film feeding motor is stopped in anticipation of the amount of overrun when the film is to be inserted.