JPS59157622A - Film end detector - Google Patents

Abstract

PURPOSE:To prevent erroneous detection by delaying a timer output during the strobe charging of a camera with a film end detector which compares the completion of a film advance by a motor with the timer output. CONSTITUTION:When a motor-driven camera incorporating a strobe does not uses the srobe, a switch F.SW is on the side OFF, so when the output of an FF95 is inverted positively, a gate 306 is inverted in level to generate a film end detection signal. When the strobe is in use, the switch F.SW in on, so when the output of the FF96 is inverted positively, the film end detection signal is sent out. Motor torque decreases because of the capacity of a power source during strobe charging, so it takes an extra time to take up a film, but the switching means for a timer is used as mentioned above to eliminate erroneous detection.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motor drive camera that uses a strobe and winds a film using a motor, and particularly relates to a film end detection device thereof.

In recent years, motor drive cameras in which film is wound by a motor have been widely used.

In this camera, the motor is automatically driven when the shutter operation ends, and the motor stops driving when the film winding ends.Therefore, even when the film is at the end, the motor is automatically driven when the shutter operation ends. This may cause the motor to run idly, wasting power, or causing the film to break.Furthermore, a similar situation may occur if the film gets caught.To prevent this, a film end detector is provided. A conventional film end detector has a timer circuit, and operates the timer circuit in synchronization with the start of driving of the motor.The timer circuit is reset in response to the end of film winding.Therefore,
If the timer circuit is not reset within a predetermined time, the end of the film is detected. However, there is an inconvenience that erroneous detection may occur depending on the operating state of the camera. If the camera has a built-in strobe device and the main capacitor of the strobe is charged at the same time as the film is wound,
It takes longer than usual to wind the film. This is because batteries are used as the camera's power source, so if you wind the film and light the main capacitor at the same time, the current capacity that can be supplied from the power battery will decrease, and the motor torque will decrease. It is. Taking this into consideration, if the predetermined time of the timer circuit is set long, the detection of the true end of the film will be delayed, which is undesirable.

This invention was made to deal with the above-mentioned circumstances,
It is an object of the present invention to provide a film end detection device that does not erroneously detect a film end even if light to a main condenser of a strobe and film winding are performed at the same time.

Hereinafter, one embodiment of the film end detection device according to the present invention will be described with reference to the drawings. First, the entire motor drive camera including this film end detection device will be explained. FIG. 1 is a schematic diagram of the entire camera. Through the positive terminal of the heavy electric 210 as a power source or the gate circuit 21.2,
It is connected to the idle feed surface control circuit 214, the constant voltage control circuit 216, the winding control circuit 21B, the converter control circuit 220, and the rewinding control circuit 222. The gate circuit 212 includes analog switches 224, 226, . ．． 22
8,230°232 and analog switch 226,22
Analog switch 23 connected to 8°230.232
4, the positive terminal of the battery 210 and the analog switch 224
, 234. Analog switch 236 is controlled by the output of the black film detector and is turned on when film is loaded in the camera. Analog switch 224, 234
is linked to the rear lid of the camera, the analog switch 224 is turned on when the rear lid changes from open to closed, and the analog switch 234 is turned on while the rear lid is closed. The analog switches 226 and 228 are linked to the release button, the analog switch 226 is turned on while the release button is pressed, and the analog switch 228 is turned on when the release button returns from the fully pressed state. The analog switch 230 turns m-on when the main switch of the strobe is closed, and turns m-on when the main switch is closed and the film winding is completed. The analog switch 232 is set to m- when the rewind switch is closed.
Turn on.

The idle feed control circuit 214 supplies a feed signal to a motor circuit 238 for film winding. A switch 240 interlocked with film winding is connected to the nitrogen feed control circuit 214 and the winding control circuit 218. The switch 240 is closed when the motor finishes winding the film frame, and outputs a winding completion signal. The output of the constant voltage control circuit 216 is supplied to the constant voltage circuit 242. The constant voltage circuit 242 supplies a constant voltage to the extraction control circuit 244. Winding control circuit 2
18 supplies a normal rotation signal to the motor circuit 238. Converter control circuit 220 provides a charging signal to strobe circuit 246. Strobe circuit 246 supplies a completion signal to converter control circuit 220 when the main capacitor is charged to a predetermined voltage.

Rewind control circuit 222 provides a reversal signal to motor circuit 238.

According to this configuration, if no film is loaded in the camera, the analog switch 236 is off, so each control circuit 214, 216, 218, 220, 22
Even if the release button is pressed, power is not wasted.

Each control circuit operates automatically in the following order only when film is loaded. When the camera is loaded with film and the rear lid is closed, the blank feed control circuit 214 is momentarily connected to the power source 210. In response, the idle feed control circuit 214 supplies an idle feed signal (normal rotation signal) to the motor circuit 238. The blank feed signal continues to be supplied to the motor circuit 238 at V when the switch 240 associated with film winding is closed three times, that is, until three frames of film have been wound. In this way, the nitrogen feed is carried out for three frames of film.
When the rear lid is closed, the analog switch 23
4 is in the on state. When the main switch of the strobe is closed, the analog switch ZSO turns m-on,
Converter control circuit 220 provides a charging signal to strobe circuit 246. The strobe circuit 246 boosts the power supply voltage and charges the main capacitor. Main capacitor is specified '1
Once charged to voltage, strobe circuit 246 provides a completion signal to converter control circuit 220 . Converter control circuit 220 stops operating in response to this completion signal, and charging to the main capacitor is stopped. This allows the main capacitor to be charged only for the minimum necessary period, thereby preventing unnecessary power consumption.

When the release button is pressed during photographing, the analog switch 226 is turned on and power is supplied to the constant voltage control circuit 216. This causes the constant voltage circuit 242 to operate and supply a constant voltage to the exposure control circuit 244. Exposure control circuit 24
4 is usually implemented as an IC and is operated by this constant voltage. The shutter and aperture are controlled to take pictures with proper exposure. When the amount of light on the subject is low, a strobe is used to take the picture.

The release button remains depressed during shutter operation.

When the shutter operation is completed, the analog switch 228 is turned on in synchronization with the return of the release button. As a result, the winding control circuit 228 supplies a normal rotation signal to the motor circuit 238, and the film is wound. When one frame of film has been wound, switch 240 is closed and a wind complete signal is provided to wind control circuit 218. This causes the motor to stop rotating. Here, when the main switch is closed, the analog switch 230 is turned on in synchronization with the winding completion signal, and the main capacitor is charged. In this way, when the film is loaded, when the release button is pressed, the main capacitor for automatic exposure photography, film winding, and flash photography is automatically charged.

Here, the main capacitor is charged after film winding is completed, and not at the same time. The problem is that both operations require a fairly large load on the power supply, so if they are performed at the same time, the battery power will be consumed significantly.

When the shooting of the specified number of frames is completed and the rewind switch is closed, the rewind control circuit 222 is activated, the motor is rotated in the reverse direction, and the film is rewound. When the film is fully wound into the cartridge, the state is equivalent to the state where no film is loaded, the analog switch 236 is turned off, all camera operations are stopped, and power supply voltage is no longer consumed. In this manner, in this embodiment, the power supply is controlled depending on the presence or absence of film in the camera, and unnecessary power consumption is avoided.

Next, each part of this power camera will be explained in detail.

2 to 4 correspond to the gate circuits 21., 2 and each control circuit 214, 216, 218, 220, 224. Hereinafter, the circuits shown in FIGS. 2 and 3 will be referred to as a first power system and a second power system, respectively.

FIG. 4 shows a circuit that supplies control signals to each gate in FIGS. 2 and 3. In the first power supply system shown in Figure 2, the film inspection switch (hereinafter referred to as the K switch) is off (open).
The second ill source system shown in FIG. 3 operates only when the first ill source system or the first ill source system has a certain moxibustion condition. The K switch is turned off when film is loaded into the camera, and turned on (closed) when film is not loaded.

B', S', T I', F', T in Figure 2
The 3' control portion is controlled by each switch B and S shown in Fig. 4.
, T.I.

It is generated according to the states of F and T3. Here, the B switch is the switch that is turned on when the rear lid is closed, the S switch is the release switch, the 'T1 switch is the winding start switch, the F switch is the main switch of the strobe,
The T3 switch is a rewind switch. The S switch and the T1 switch are linked to the release button, and the Sp switch is turned on when the release button is pressed down, and the T1 switch is turned on when the release button is released. The F switch and T3 switch are manual switches. When the K switch is on, transistors Q51, Q52°Q96 are cut off.

The collector signal of transistor Q96 serves as a power supply signal to the first power supply system in FIG. Therefore, the first power supply system shown in FIG. 2 does not operate when the K switch is on, that is, when there is no film, and wasteful consumption of power is prevented.

When the switch is turned off due to film loading, resistor R19, diode D4 . D5 through transistor Q51. A current flows between the base and emitter of Q52°Q96, and the transistor Q51. Q52. Q9
6 turns on.

By turning on transistor Q96, the first power supply system (second
(Fig.) is supplied, and the first power supply system starts operating. By turning on transistors Q51°Q52, transistors Q48°Q49 . Q50 turns on, and then F transistor Q33. Q34. Q35. Q53. Q54゜Q
55. Q56 turns on. Furthermore, transistor Q2B
, Q47. Q57. Q5B, Q29゜Q30. Q44.
Q45. Q31. Q32゜Q59 turns on, and switches B, F, S, etc.

TI and T3 operations become possible.

The B switch and F switch are off when they are on the power supply vCC side, and on when they are on the ground side.

When switches B and F are off, transistors Q26.
Q19. Q20. Q21. Q23゜Q22. Q24. Q
25 turns on. When transistor QZ4 turns on, transistor Q27 also turns on, so transistor Q2g
is the cutoff. Therefore, B', F' times signal vC
Conversely, when the B and F switches are on, the transistor Q26 is cut off, so the transistor Q23. Q22. Q24゜Q25. Q21. Q
20. Q19 is also turned off.

By turning off transistor Q24, transistor Q27
Since transistor IQ2B is also turned off, transistor IQ2B is turned on. Therefore, the Bl, F/ signal becomes the ground level.

When the S, TI, and T3 switches are off, the transistor Q43 is similarly on and Q47 is cut off, so the S', Tl', and T3' signals are at the VCC level. S
, TI, When the T3 switch is on, transistor Q43 is cut off and Q47 is on, so S',
TI'.

The T3' signal goes to ground level. In this way, each control signal changes from the vCC level to the ground level as the switch turns from off to on.

In the first power supply system shown in FIG. 2, when each control signal from FIG. Outputs pulses. When the film is loaded, the rear lid is closed, and the level of the B' signal changes from positive to negative, for a predetermined time determined by capacitor C2,
The output of NAND gate 5 becomes negative level. This negative pulse sets a flip-flop consisting of NAND gates 12 and 13.
output becomes negative level. Therefore, the inverter 51 outputs an idle feed hold signal. The hold signal is a positive signal for operating each control circuit. below,
Each signal will be explained as positive logic. At this time, since the output of the NAND gate 49 also becomes a positive level, the 2' source system (third circuit) becomes operational. The negative pulse output from the NAND gate 5 causes the NAND gate 9°IO to output a timer reset pulse and a film counter reset pulse, respectively. These reset pulses cause the third
Flip-flops 87-99, 59, 60, 63.
64 is reset. A timer 280 consisting of flip-flops 87 to 99 counts the output signal of the JH generator 282. Q of flip-flop 95.96 of timer 280
The output is provided to a film end detector 284. Oscillator 282 oscillates at a frequency determined by capacitor C6 and resistor R2.

An idle feed hold signal (Thus, the output of the NAND gate 71 becomes a positive level, and a normal rotation signal is output from the inverter 7B. This is the desired feed signal in FIG. 1.

A detailed circuit diagram of motor circuit 238 is shown in FIG. In response to the normal rotation signal, transistors Q60°Q64. Q67 is turned on, current flows from the positive terminal (+-) to the negative terminal, and the motor M rotates in the forward direction.

The film is wound by normal rotation of the motor M. When one frame of film has been wound, the T2 switch (switch 240 in FIG. 1) is closed (turned on). The T2 switch turns off during winding. A feed counter consisting of a Flip Flora Pro 3.64 counts the number of times the T2 switch is turned on. Flip-flops 59, 60, NAND gate 6
1.62 is a circuit for preventing child yattering. T2
When the switch is turned on three times, the flip-flop 63.6
Both Q outputs of 4 become positive level, and NAND gate 6
6 becomes a negative level. As a result, the normal rotation signal becomes a negative level, and the inverter 76 outputs a brake signal. In FIG. 5, the brake signal causes transistors Q62. Q63. Since Q6B is turned on, both ends of the motor M are short-circuited, and an electromagnetic brake is applied to the motor M. As a result, when the rear lid is closed, the film is automatically advanced three frames. Here, since the output of the inverter 68 becomes a negative level, the reset of the flip-flops 72 and 73 is released. Thereafter, when a predetermined period of time has elapsed, the output of the flip-flop 89 of the timer 280, which has been operating since the start of the idle feed, causes both the Q outputs of the flip-flops 72 and 73 to become positive levels, and the winding reset signal is sent from the inverter 80. is output.

As a result, the output of the NAND gate 8 in FIG. 2 becomes a positive level, and the flip-flops 12 and 13 are reset. The output of NAND gate 13 is.

Since it becomes a positive level, the output of the NAND gate 49 becomes a negative level, and the operation of the second power supply system (FIG. 3) is stopped. Therefore, the electromagnetic brake is applied to the motor M because
Several 10 to several 10 + Omeee are installed to prevent unnecessary power consumption.

In addition, if some abnormality occurs during the idle feed operation and it takes a long time to wind three frames, the full feed reset signal number output from the flip-flop 98 of the timer 280 is sent to the flip-flop 12.13. is reset. The operation of the second power supply system is completed. This 9 saves power consumption when an abnormality occurs. The operations up to this point are from loading the film to feeding the film before starting shooting. The above explanation is shown in Section 9 Section 1 as a flowchart. In this flowchart, the steps indicated by broken lines are manual operations by the photographer, and unless the photographer performs a stiff operation, the flow enters a standby state at that operation step.

Next, a normal photographing operation will be explained. Here, when the main switch F is on, the main capacitor of the strobe is photoelectrically charged. F switch goes from OFF to ON, F'
When the signal changes from the vCC level to the ground level, the NAND gate 34 (Figure 2) is activated as in the case of the B switch.
A negative pulse is output from flip flop 3,6
37 is set, and the output of the NAND gate 37 becomes a negative level. As a result, a converter hold signal is output from inverter 5B. This is the charging signal supplied to strobe circuit 246 in FIG.

A detailed circuit diagram of the strobe circuit 246 is shown in FIG. 6. The converter hold signal causes transistors Q93. Q
90 is turned on, transistor Q90. Q91, Q9
2. The DC-DC converter 290 consisting of a transformer T starts oscillating. The oscillating boosted output of converter 290 is charged to sub capacitor C8 and main capacitor C10. The capacitance of the sub capacitor C8 is much smaller than that of the main capacitor C10. When the terminal voltages of capacitors CB and CIO exceed the discharge starting voltage of gas discharge tube XJ-, the photoelectric charge of sub-capacitor C8 flows through gas discharge tube X1, and transistor Q99. Q95 turns on. The charge on the main capacitor C10 is not discharged due to the presence of the diode D9. By turning on transistor Q95, a converter reset signal (charge completion signal in FIG. 1) is output.

In the first power supply system (FIG. 2), the flip-flops 36 and 37 are reset by the converter reset signal to hold the converter and stop generating the signal. This causes the DC-DC converter Z90 to operate or stop.
Charging of the main capacitor C10 ends. That is, when the main capacitor C10 is charged to the discharge starting voltage of the gas-inlet discharge tube XZ, charging is automatically terminated.

Here, the discharge starting voltage of the gas discharge tube Xl is selected to be a voltage at which the flash discharge tube X2 can emit light with a predetermined amount of light emission.

In this way, the DC-DC converter 29[theta] stops operating after charging the main capacitor CZ[theta] with the desired voltage, so that power is not consumed unnecessarily.

When the release button is pressed, the S switch turns on. S
Due to the fall of the p' signal, the flip-flop 20.2z
(FIG. 2) is set, the 21st source system is turned on, and the AE hold signal is output from the n5 inverter 52. A.E.
A CTL signal is output from the NAND gate 82 in response to the hold signal, and is supplied to the constant voltage circuit 242 (FIG. 1).

A detailed circuit diagram of the constant voltage circuit 242 is shown in FIG. CT
When the L signal is supplied, a voltage determined by the ratio of resistors R31 and R32 is output to the output terminal VOut. Due to the stiffness, the exposure control circuit 244 is activated and automatic μ exposure photography is performed.

Here, in the strobe circuit (factor 6), switch SW
1 is linked with main switch F. Therefore, when the main switch F is on, the X contact switch SW2 is also turned on in conjunction with the shirt release, and the flash discharge tube X2 is triggered. This allows the main capacitor CZO
A discharge current flows through the flash discharge tube X2, and flash light emission is obtained.

When the S,' signal falls, a timer reset signal and a film counter reset signal are also output. timer 280
When a predetermined period of time has elapsed after being reset, an Sp reset signal is output from the flip-flop 9. The output of the NAND gate 21 is at a positive level, but since the S,' signal is at a negative level, the output of the NAND gate 45 remains at a positive level, and the AE hold signal is maintained.

When the shutter operation is completed, the release button returns and the S,
When the switch is turned off and the S,' signal returns to the positive level, the output of the NAND gate 45ρ) becomes negative level, and the A
E-hold signal generation stops. As a result, foot′1
The operation of the pressure circuit 242 also stops.

If the camera is placed in a bag or the like and the release button is pressed undesirably and continues to press Z9, the timer 280 clocks and the inverter 46 outputs an AE reset signal after a certain period of time (90 rounds in this case) has elapsed. Ru. Due to this, the AE hold signal goes to negative level, and as expected,
Constant voltage circuit 242 is turned off. In this way, the power source is prevented from being consumed due to erroneous operation. The above explanation is shown in the form of a flowchart in FIG.

When shooting is finished and the release button returns to its original position, first press S.
The p switch is turned off and then the T1 switch is turned on. With the fall of the signal T1', the flip-flops 28 and 29 (Fig. 2) are set, the second power supply system is activated, and the winding hold signal is output from the inverter 53, as well as the timer reset signal and the film counter. A reset signal is also output. A normal rotation signal is supplied to the motor circuit 238 in response to the winding hold signal, and the motor M rotates in the normal direction. - T while winding a frame of film.
2 switch is turned off, and - when winding of the piece is completed, T
2 switches are turned on. When the T2 switch is turned on from off, the Q output of the □ flip-flop 63 becomes a positive level, and the output of the NAN'D gate 67 becomes a positive level. As a result, the normal rotation signal ends and the brake signal is no longer output, so that the rotation of the motor M stops instantly. As in the case of the idle feed operation, at this time as well, the second power supply system uses the timer ztt.

When the Q output of the flip-flop 89 is obtained, the operation is stopped and no extra power is consumed.

Next, the film end detection operation when a specified number of shots have been taken will be described. A detailed circuit diagram of the film end detector 284 is shown in FIG. The Q outputs of the flip-flops 95 and 96 of the timer 280 are each NAN.
It is input to one input terminal of D gates 300 and 302. The movable contact piece of the main switch F of the strobe is directly connected to the other input terminal of the NAND gate 300, and the inverter 3
04 to the other input terminal of the NAND gate 302. The output of NAND gate 300°302 is NAN
It is output as a film end signal via D gate 306 and supplied to NAND gate 84 (FIG. 3).

In such a film end detector, when the strobe main switch F is off, the NAND gate 3
The output of NAND gate 300 corresponds to the Q output of flip-flop 95. When the Q output of the flip-flop 95 changes from a negative level to a positive level, the output of the NAN'D gate 300 changes from a positive level to a negative level. As a result, a positive film end signal is output from the NAND gate 3θq. When the F switch is on, the output of NAND gate 300 is always at a positive level, and the output of NAND gate 302 corresponds to the Q output of flip-flop 96. flip flop 9
When the Q output of NAND gate 302 goes from negative to positive level, the output of NAND gate 302 goes from positive to negative level. This results in
A positive film end signal is output from NAND gate 306.

Since the timing of the Q output of the flip-flop 96 is later than that of the Q output of the flip-flop 95, when the F switch is on, the output timing of the film end signal is delayed from when the F switch is off. When the F switch is on, the undercurrent supply capacity of the battery 210 is reduced due to the operation of the DC-DC converter 290, and the motor torque is weakened, but the detection timing is delayed, so erroneous detection of the end of the film is prevented. be done.

In response to the film end signal, the output of the NAND gate 84 becomes a negative level, the generation of the normal rotation signal is stopped, and the rotation of the motor is stopped. At the same time, from inverter 85
An ON signal is output, and a CTL signal is output from the NAND gate 82.

As a result, a constant voltage is applied to the exposure control circuit 244,
A built-in PC element is oscillated and the photographer is notified of the end of the film. After this, a winding hold reset signal is output from the inverter 101, and the NA
Since the output of the ND gate 29 becomes a positive level, the NAND
The output of gate 49 becomes negative level. This allows the second
When the power supply system is turned off, PCV shooting ends. Alternatively, the photographer may press the rewind switch T by the oscillation sound of the PCv element.
When T3 is turned on, a reverse signal is output from the inverter 55 due to the fall of the T3' signal.

In the motor circuit shown in FIG. 6, the reverse signal causes transistor Q61. Q65. Q66 turns on, current flows from the negative terminal to the positive terminal, and the motor M rotates in reverse. As a result, the film is rewound to the cartridge side. When the film is completely rewound and the K switch is turned on, the entire power supply system is turned off and the operation ends.

On the other hand, if the film is normally wound and the T2 switch is turned on and the second power supply system is turned off, and the main switch F is turned on, the strobe is charged at the same time. The winding reset signal turns off the second power supply system, but since the converter signal is output, the above-mentioned strobe is charged. After this, the camera enters a standby state for pressing the release button as shown in FIG. The actions up to this point are
This is shown as a flowchart in Figure 1.

As explained above, this embodiment provides a film end detection device that can cope with the long opening of film winding while the main capacitor is being charged and that does not cause false detection in a motor drive camera that is connected to a strobe. provided.

Next, a second embodiment of the present invention will be described with reference to FIG. 12. In this second embodiment, the converter hold signal output from the NAND gate 58 (FIG. 2), rather than the signal from the main switch F,
00,302 is controlled, flip-flop 95.96
One of the Q outputs is output as a film end signal. Even in such a configuration, the film end detection timing is delayed during the period in which the converter hold signal is generated, that is, during the charging period of the main capacitor, and erroneous detection is prevented.

As described above, according to the present invention, since the film end detection timing is changed while the main capacitor of the strobe is being charged, a film end detection device that can always accurately detect the film end is provided. It should be noted that the present invention is not limited to the embodiments described above, and various changes can be made to the detailed style of the camera, etc.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic diagram of a motor drive camera including an embodiment of a film detection device according to the present invention, FIGS. 2 to 4 are circuit diagrams of the power supply system of this camera, and FIG. 5 is a motor circuit of this camera. 6 is a circuit diagram of the strobe circuit of this camera, FIG. 7 is a circuit diagram of a constant pressure circuit of this camera, FIG. 8 is a circuit diagram of an embodiment of the film end detection device, and FIG. 11 through 11 are flowcharts showing the overall operation of this camera, and FIG. 12 is a circuit diagram of a second embodiment of the film end detection device according to the present invention. 210...Battery, 212...Gate circuit, 214...
... Nitrogen feed control circuit, 216 ... Constant pressure control circuit, 2
18... Winding control circuit, 220... Converter control circuit, 246... Strobe circuit. Applicant's agent Patent attorney Takehiko Suzue Figure 9 Figure 10

Claims (1)

[Claims] A film end detection device used in a camera with a built-in strobe light source includes a film winding motor, a single power supply that supplies current to the film winding motor and the strobe light source, and a single power supply that supplies current to the film winding motor. A timer means that starts a timing operation from the start of power supply and is reset at the end of film winding, and a means for detecting the end of the film if the timer means is not reset within a predetermined time after the start of timekeeping, and supplies power to a strobe light source. A film end detection device for extending the predetermined time.