JPS59188623A - Film counter device of camera - Google Patents

Abstract

PURPOSE:To obtain a reverse-counting film counter which requires no manual setting of the number of film frames by reading the number of film frames recorded in a cartridge, and constituting so that the prescribed number of said frames is subtracted from said frame in number whenever a shutter is operated. CONSTITUTION:When a cartridge 2 is loaded and a rear cover is closed, the number of frames recorded in a film information area 4 is detected by contact pieces 6, 7, and sent to a code converter 8. The converter 8 converts its information to the film frame in number, sends it to a register 9, and displays the number of film frames on an indicator 16. When a shutter release button is pushed after feeding no-load, a shutter 10 is operated, and a NAND circuit goes to L, therefore, a counter 13 is operated, the contents attains to 1, and an operating circuit 14 subtracts ''1'' from the number of frames stored in the register 9. When the shutter 10 is operated, a switch of a one frame feed detecting mechanism 28 is changed to on from off, a motor 26 is rotated, the shutter 10 is charged, and also a film is shifted by one frame. Thereafter, in the same way, the display of the indicator 16 is reduced ''1'' by ''1''.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a film counter device for a camera, and more particularly to a backward counting type counter device that displays the number of remaining frames.

There are two types of film counter devices: forward counting type that displays the number of frames that have been shot, and backward counting type that displays the number of remaining frames. The forward counting method is convenient to handle because it does not require the operation of a film counter device, but on the other hand, it has the disadvantage that it is not possible to know the number of remaining frames.

On the other hand, with the backward calculation method, you can know the number of remaining frames, but if you do not count the number of film frames in advance,
There is a problem that it becomes useless as a counter.

SUMMARY OF THE INVENTION An object of the present invention is to provide an improved backward-counting film counter device that eliminates the need for a photographer to manually count the number of film frames.

The present invention reads the number of film frames recorded on the cartridge, and from this number of film frames, each time the shutter is activated, a fixed number is set, for example, "1" for a full size, rO, 5J, or 2 for a half size. Each time it is activated, "1" is subtracted.

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

A cartridge 2 containing a film 1 is provided with a bar code area 3 and a film information area 4 on its outer periphery. In the barcode area 3, information indicating manufacturing lot number, film type, sensitivity, etc. is recorded as a barcode. In the film information area 4, information on the type of film frame number, film sensitivity, and film latitude, which are coded by the conductive portion 4a and the non-conductive portion, are recorded.

Information indicating the type of film frame number is detected by the contact pieces 6 and 7. That is, when the contact piece 6.7 comes into contact with the conductive part 4a in the film information area 4, the low level (rL
A signal of high level (hereinafter referred to as rHJ) is input to the code converter 8, and when the non-conducting part is contacted, a signal of high level (hereinafter referred to as rHJ) is input to the code converter 8. This code converter 8 is for converting information representing the type of film frame number into a binary film frame number, and uses a diode matrix circuit or ROM, and stores the obtained film frame number in a register 9. send. The shutter 10 outputs a shutter activation signal and sends it to the NAND circuit 11. This shank actuation signal can be obtained by providing a switch that outputs ONL and rHJ signals when the shutter drive member moves to the charge release position.

The NAND circuit 11 is configured to also receive the multiple exposure signal inverted by the inverter 12, and when a shutter activation signal is input during normal photography, not multiple exposure photography, its output terminal is inverted to rLJ. do. This N
When the output terminal of the AND circuit 11 is inverted to "L", the counter 13 is incremented. This counter 13 has a back cover opening/closing signal obtained from a switch that detects opening/closing of the back cover (not shown) inputted to its reset terminal, and is reset when the back cover is opened.

The contents of the counter 13 and the contents of the register 9 are sent to a subtracter 14. The subtracter 14 calculates the number of remaining frames by subtracting the contents of the counter 13 from the contents of the register 9, and sends the result to the decode driver 15 for display on the display 16. This subtracter 14 and register 9
is controlled by the controller 17, and updates the data in the register 9 and performs subtraction in the subtracter 14 at predetermined intervals. Note that the code converter 8° register 9. Counter 13. Subtractor 14. It is preferable that the controller 17 is composed of a microcomputer.

The output terminal of the subtracter 14 is connected to a NOR circuit 18, which activates an oscillator 19 when these bits are rLJ. The output of this oscillator 19 is rHJ when it is not in operation, and when the input terminal becomes rHJ, it outputs a pulse of, for example, IHz, turns the transistor 20 on and off, and causes the display 16 to blink.

As a result, the display 16 displays a blinking number "zero" to warn that the film should be replaced. Note that if the upper five bits of the output terminal of the subtracter 14 are taken, the display 16 starts blinking when the number of remaining frames reaches "1". When the number of remaining frames of the film becomes zero, the output of the NOR circuit for one day becomes rHJ, and this signal is sent to the AND circuit 22. The AND circuit 22 also receives a signal obtained by delaying a signal obtained from a film detection switch 23 disposed in the film path near the cartridge chamber and a back cover closing signal by a delay circuit 24. Therefore, the back cover is closed,
The number of remaining frames is zero, and there is no film 1 on the film path.
While this exists, the output of the AND circuit 22 becomes "H", and the forward/reverse circuit 25 is switched to the reverse direction. This causes the motor 26 to start rotating in reverse, allowing the exposed film 1 to be rewound into the cartridge 2. The delay circuit 24 is provided to prevent the output of the AND circuit 22 from becoming rHJ and rotating the motor 26 in reverse before the subtracter 14 completes its calculation when the cartridge is replaced.

The rotation of the motor 26 is transmitted to the film feeding mechanism 27 and the shutter 10 to wind the film and center the shutter. A one-frame advance detection mechanism 28 operates in conjunction with the film advance mechanism 27, and detects that the film 1 has been wound up by one frame.

This l-frame speed detection mechanism 28 includes a cam that rotates together with a sprocket that transports the film and has a notch on its outer periphery.When this cam rotates once, it enters the notch.
It consists of a cam follower that is pushed out through the notch after the shutter is activated, and a switch that turns off when the cam follower enters the notch, and outputs an rHJ signal while the switch is on. Note that the film feeding mechanism 27. Regarding the shank 10 and the one-frame feeding mechanism 28, for example, Japanese Patent Application Laid-Open No. 57-14762
It is disclosed in detail in Publication No. 3.

The signal output from the one-frame advance detection mechanism 28 is sent to a rising edge detection circuit 29 and an OR circuit 30. The output of this rise detection circuit 29 is the output of the inhibition gate circuit 31.
The data is sent to the blank feed counter 32 via the frame feed counter 32, where it is detected that the switch of the one frame feed detection mechanism 28 has been turned on and off twice. At this time, the output terminal B of the blank feed counter 32 becomes rHJ, so the inhibition gate circuit 31 closes and the counter operation of the blank feed counter 32 is stopped.

Further, an output terminal B of this empty feed counter 32 is connected to an inverter 33. The output signal of this inverter 33 and the back cover closing signal which becomes rHJ when the back cover is closed are A
The output signal of the AND circuit 34 is sent to the inhibit gate circuit 35 via the OR circuit 30. The prohibition gate circuit 35 is provided so that a forward rotation command can be sent to the forward/reverse control circuit 25 only when the output of the AND circuit 22 is rLJ.

Next, the operation of the present invention will be explained. When the cartridge 2 is loaded into the cartridge chamber and the back cover is closed, the information indicating the type of film frame number recorded in the film information area 4 will be
It is detected by contact pieces 6 and 7 and sent to code converter 8. The code converter 8 converts the input information into the number of film frames and sends it to the register 9. Patrone 2
Immediately after loading, the contents of the counter 13 are zero, so
The number of film frames stored in the register 9 is displayed on the display 16.

On the other hand, when loading the cartridge 2, the empty feed counter 32
The output terminal of is rLJ. This signal is transmitted to the inverter 33
After being inverted to rHJ, it is sent to the AND circuit 34.

When the back cover is closed after loading Patrone 2, the AND
The output of the circuit 34 becomes rHJ, and this signal is sent to the forward/reverse control circuit 25 via the inhibition gate circuit 35. The forward/reverse control circuit 25 forms a normal rotation circuit to rotate the motor 26 in the normal direction when the inhibition gate circuit 35 is rHJ. When the motor 26 rotates normally, the film l is fed by the film feed mechanism 27 and the shutter 10 is charged.

During idle feeding, even if the cam follower enters the cam of the one-frame feed detection mechanism 28, the cam rotates, so the cam follower can be forcibly pushed out.

Therefore, the switch of the one-frame feed detection mechanism 28 is turned on.
It repeats OFF, and when ON, it outputs the rHJ signal and sends it to the rising edge detection circuit 29 and OR circuit 30. The rise detection circuit 29 generates a pulse at the timing when the switch is reversed from OFF to ON, and sends it to the idle feed counter 32 via the inhibit gate circuit 31. When the film transport mechanism 27 transports two blank frames, a total of two pulses are output from the rising edge detection circuit 29. This 2
When pulses of
is closed, and the output of the inverter 33 becomes rLJ.

However, the switch of the piece speed detection mechanism 28 is already OFF.
The output of the OR circuit 30 is rHJ.
Therefore, the motor 26 continues to rotate.

When the first frame is transferred to the exposed position by the rotation of the motor 26, the switch of the one-frame feed detection mechanism 28 is turned OFF.
Therefore, the rotation of the motor 26 is stopped.

When the shirt release button is pressed after the above-mentioned blank feed, the shank 10 is operated to expose the first piece at the exposed position. When this shutter 10 operates, the NAND circuit 1
Since the output of 1 changes to "L", the counter 13 performs a counting operation and its contents become rlJ in decimal notation. Since the subtracter 14 subtracts the contents of the counter 13 from the number of film frames stored in the register 9, for example, for a film with 24 exposures, the number displayed on the display 16 will be "23".
become.

When the shutter 10 operates, 1.1 frame advance detection mechanism 2
Since switch 8 changes from OFF to ON, 1 motor 2
6 rotates again to fire the shutter 10, and at the same time the film is transported by one frame. Similarly, when the shutter 10 is operated, the value on the display 6 decreases by 1, and the motor 2 is automatically started to wind the film and yarn the shutter.

When all the pieces have been photographed, the display 16 will show the number 2 “Zero”.
Display. At this time, the output of the NOR circuit 18 becomes rHJ, so the oscillator 19 operates and turns on the power to the display 6.
Turn it off and display the number "1" in a blinking state. At the same time, since the E force of the AND circuit 22 becomes rHJ, a reversal circuit is formed, and the mode 26 automatically starts reversing to rewind the film 1 into the batten 2. When all the frames are rewound in the cartridge 2, the film detection switch 24
is OFF"5, so the reverse rotation of the motor 2G is stopped. After this winding, the back cover is opened to take out the cartridge 2. Then, the counter 13 and the empty feed counter 32 are set at 1°. Ru.

Since the number of shutter operations is subtracted from this information, the number of remaining frames on the film 5 can be displayed without any special operations.

F'4, brief description of the drawing The drawing is a block diagram showing one embodiment of the present invention.

≧...Film 2...Patrone 3 4...Film information area 4a...Conducting part.

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Claims (2)

[Claims] (1) In a camera that uses film in which coded film information indicating the number of film frames is recorded on the outer circumference of the cartridge, there is a means for electrically reading the film information, and a means for electrically reading the film information and converting the read film information into the number of film frames. a means of converting it into
A counter device comprising: a calculation means for storing the number of film frames obtained and subtracting a fixed number each time the shutter is operated; and a display for displaying the calculation result of the calculation means. (2) The calculation means includes a register that stores the number of film frames, a counter that counts the number of times the shutter is activated, and a subtracter that subtracts the content stored in the counter from the content stored in the register. A film counter device according to claim 1, characterized in that: