JP2579164Y2 - Camera with automatic film winding mechanism - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera having an automatic film winding mechanism, and more particularly, to a control technique for maintaining a constant film feeding amount in a frame feed or the like.

[0002]

2. Description of the Related Art In recent years, cameras have become smaller and lighter, and automation has been further advanced. As a part of this, a compact camera usually has an automatic film winding mechanism so that frame advance after an exposure operation is automatically performed. Generally, DC is used as a film winding power.
Motors are frequently used. On the other hand, a mechanical film counter is mounted to measure the film feed amount and control the DC motor. The mechanical film counter includes a contact member that engages with and engages with a sprocket hole formed in the film, and sequentially outputs pulses of a number corresponding to the feeding amount. This pulse train is counted, and the DC motor is stopped when the number of pulses corresponding to the frame feed amount set in advance is output.

[0003] Generally, a mechanical film counter has a contact member accompanied by mechanical sliding, so that it is accompanied by a noise pulse due to chattering. If the signal containing the noise pulse is counted as it is, there is a risk of erroneous counting. For this reason, sampling and counting of pulses are performed after a predetermined delay time sufficiently longer than an indefinite chattering period has elapsed from the time when the pulse signal falls.

[0004]

Heretofore, this delayed sampling has been performed up to the last pulse corresponding to a preset feed amount. That is, the last pulse
The DC motor has been stopped after a predetermined delay time has elapsed from the signal falling point. Therefore, the film runs idle during this delay time. Although the delay time is constant, the idling distance fluctuates due to various factors. For example, if the stiffness of each film mounted on the camera varies, or if the output torque of the DC motor varies due to fluctuations in battery voltage, the actual air transport distance will not be constant.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, the present invention provides a control method of a DC motor capable of always keeping the film idle distance, that is, the frame feed amount constant. The purpose is to do. The measures taken to achieve this object and to solve the problems of the prior art are as follows. That is, a camera having an automatic film winding mechanism according to the present invention includes, as general components, a feeding motor for winding and feeding a film having a sprocket hole, and an interlocking engagement with a moving sprocket hole. And a mechanical film counter for sequentially outputting signals including the number of pulses corresponding to the feeding amount with chattering and including a contact member. Furthermore, small of each pulse
Such a means for Kutomo detecting the signal fall time of the trailing edge, only long enough predetermined time than a chattering period, delayed sampling for delayed from the time edge detection signal falling to output a sampling signal Means. Finally, as a characteristic component of the present invention, the pulse is sequentially counted according to the delayed sampling signal, and the last pulse corresponding to the preset feed amount is specified, and in synchronization with the signal falling point of the last pulse. Control means for controlling the feed motor and immediately stopping the feed of the film is provided.

Preferably, the control means includes means for setting a predetermined feed amount necessary for frame feed of the film, starting the feed motor at the start of frame feed, and synchronizing with the falling edge of the signal of the last pulse. And a driving means for forcibly stopping the feeding motor.

[0007]

According to the present invention, the feeding motor is immediately stopped in synchronization with the falling edge of the signal of the last pulse, and the film feeding is completed. Unlike the related art, since the idle running of the film due to the delayed sampling is excluded, the frame can be always fed at a constant interval. On the other hand, at the time before the last pulse is generated, erroneous counting does not occur because delay sampling is performed and pulse counting is performed as in the conventional case. That is, when the counting of the immediately preceding pulse is completed, the next final pulse can be specified, and therefore, film feeding can be immediately stopped in synchronization with the signal falling timing without delay sampling.

The film feeding control method according to the present invention can be applied to the frame feeding at the end of the exposure operation for each frame. The present invention is also applicable to a case where the film is moved at a constant speed by a predetermined feeding amount. The technical scope described in claim 1 includes the latter case.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing an electrical configuration of a camera having an automatic film winding mechanism according to the present invention. As shown in the figure, the apparatus includes a feed motor 1 for winding and feeding a film having a sprocket hole formed therein.
It has. Generally, a DC motor that performs a continuous rotary motion is used. Also, a mechanical film counter 2 is incorporated to monitor the film feed amount.
The counter includes a contact member that engages with the moving sprocket hole and outputs a signal B composed of a number of sequential pulse trains corresponding to the feed amount. Since the contact member involves mechanical sliding, a noise pulse often occurs after the falling of the signal of each pulse. This noise pulse causes erroneous detection.

Signal falling detecting means 3 is connected to the mechanical film counter 2 to detect a falling point of the signal B and output a corresponding detection signal C. The delay sampling means 4 is connected to the detection means 3. The delay sampling means 4 outputs the sampling signal D with a delay from the signal falling point for a predetermined time T sufficiently longer than the undefined chattering time. Finally, the control means 5 is connected to the detection means 3 and the delay sampling means 4. The control means 5 sequentially counts the pulses included in the signal B according to the delayed sampling signal D, specifies the last pulse corresponding to the preset feed amount, and synchronizes with the signal falling point of the last pulse. The feed motor 1 is braked to immediately stop feeding the film. The control means 5 includes a means for setting a predetermined feed amount required for the frame feed of the film and a start signal by supplying a normal rotation signal A to the feed motor 1 at the start of the frame feed and a signal falling of the last pulse. And a driving means for supplying a brake signal E to the feed motor 1 in synchronization with the time to apply braking.

In the present embodiment, the signal falling detecting means 3, the delay sampling means 4, and the control means 5 are constituted by software, and the CP of the camera is used.
Built in U6. However, the present invention is not limited to this, and it is a matter of course that at least a part of each unit described above may be configured by hardware.

FIG. 2 is a schematic view showing the mechanical structure of a camera provided with an automatic film winding mechanism according to the present invention. The upper half shows a sectional structure, and the lower half shows a planar shape. At one end of the camera frame 7, a patrone 9 for feeding out the film 8 is rotatably mounted. On the other hand, a film winding shaft 10 is rotatably attached to the other end of the camera frame 7, and winds the film 8 as shown by the arrow. The feed motor 1 is connected to one end of the hoisting shaft 10 via a wheel train. Further, a mechanical film counter 2 is attached to monitor the feed amount of the film 8. The counter 2 includes a contact member 12 that engages with a sprocket hole 11 formed in the film 8. The contact member 12 comprises a sprocket gear and a brush coaxially fixed thereto. A CPU 6 is connected to the counter 2 and the motor 1, and performs automatic film feed control.

FIG. 3 is a schematic diagram showing an example of the detailed structure of the mechanical film counter 2, in which the left half shows an exploded state and the right half shows an assembled state. The mechanical film counter 2 has a laminated structure of a contact member 12 and a substrate 13. The contact member 12 is composed of a sprocket gear 14 and a brush 15 coaxially attached thereto. On the other hand, a pair of electrodes 16
Are formed. The brush 15 and the electrode 16 slidably come in contact with the rotation of the sprocket gear 14, and generate a pulse accompanied by chattering noise. In this embodiment,
Two pulses are output for each rotation of the sprocket gear 14. However, the present invention is not limited to this. The electrodes formed on the substrate 13 may be further divided to improve the detection resolution. In any case,
A pulse is output according to the rotation amount of the sprocket 14. The amount of rotation of the sprocket gear 14 is proportional to the amount of film 8 fed.

Next, the operation of the camera having the automatic film winding mechanism according to the present invention will be described in detail with reference to FIG. In this example, four pulses are defined as a preset feed amount. This number is merely an example, and is actually automatically determined in consideration of the ISO standard of the film, the number of teeth of the sprocket gear 14, and the like. First, when the exposure operation is completed, the control means 5 outputs the normal rotation signal A and starts the film supply motor 1. As a result, the film feeding starts, and the mechanical film counter 2 outputs a signal B including successive pulses according to the feeding amount. As shown in the figure, the leading edge and trailing edge of each pulse include a noise pulse caused by chattering of the contact member. The signal fall detecting means 3 sequentially detects the signal fall contained in the signal B and outputs a corresponding detection signal C. Further, the delay sampling means 4 outputs the sampling signal D with a delay of a predetermined time T sufficiently longer than the undefined chattering time with reference to the signal falling point of each detected pulse. Generally, the chattering period is on the order of several μs, and the predetermined delay time T is set to be sufficiently longer than this and to be on the order of several ms. The control means 5 sequentially counts the number of pulses included in the signal B in synchronization with the delayed sampling signal D. For example, when the H level of the signal B is detected at the first sampling timing and subsequently the L level of the signal B is detected at the second sampling timing,
It can be confirmed that the first pulse has been output, and a reliable count can be performed. In this way, the pulses are counted sequentially, and three pulses can be confirmed at the sixth sampling timing. At this point, it can be expected that the fourth final pulse will be input next. Therefore, after the seventh sampling timing has elapsed, it stops fourth the feeding force the film feed supplied to the motor immediately brake signal E in synchronism with the generation timing of the signal falling edge of the pulse.

On the other hand, conventionally, at the time of the eighth sampling timing, the output of the last pulse is confirmed and then the motor is stopped. Therefore, as shown by the dotted line portion of the normal rotation signal A, in the related art, the film runs idle only for a predetermined delay time T.
The amount of free running varies under the influence of various environmental factors.

Finally, referring to the flowchart of FIG.
The control software program built in the CPU 6 will be described in detail. When the start is started in step S1, initialization is first performed in step S2, and the count of the built-in counter is reset to zero. Subsequently, the motor is started in step S3. Since the motor starts rotating forward and the film is fed, signals including pulses are sequentially output. In step S4, it is determined whether or not the falling of the signal has been detected. If detected, a T time delay is applied in step S5. Thereafter, the signal level is determined in step S6. If it is at the L level, it can be confirmed that one pulse has been input, so the count is incremented by one in step S7. After repeating such a procedure, it is determined whether or not the count has reached 3 in step S8. When the count reaches 3, the last pulse is input next. Therefore, the signal falling of the last pulse is determined whether or not detected in step S9. If detected, the motor is immediately stopped in step S10. In the program described above, the trailing edge of the pulse is used to facilitate understanding of the present invention .
Kicking it is performed to count the pulses on the basis of only the signal falling edge detection, in fact rie Din as shown in the timing chart of FIG. 4 in order to perform a more reliable pulse counting
It is preferable to determine the level of the signal B based on the detection of both the falling edge of the signal at the leading edge and the trailing edge . That is, the signal at the leading edge
Trailing after a predetermined time has elapsed from rising under Chi detection time
It is preferable that the falling edge of the signal detected at the edge is treated as valid.

[0017]

As described above, according to the present invention, according to the present invention, pulses are sequentially counted in accordance with a delayed sampling signal, the last pulse corresponding to a preset film feed amount is specified, and the signal of the last pulse falls. Since the feed motor is controlled in synchronism with the time point and the film feed is stopped immediately, the idling of the film due to the delay time can be effectively removed unlike the conventional method, and the constant interval Has the effect that frame advance can be performed. Therefore, not only the appearance after the film development is improved, but also the frame position detection of the film can be simplified in the case of performing a printing process in a later step. Therefore, there is an effect that it can greatly contribute to automation of the printing machine. In addition, since frame advance can always be performed at a constant interval, there is an effect that double exposure can be surely prevented without overlapping adjacent frames.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of a camera having an automatic film winding mechanism according to the present invention.

FIG. 2 is a schematic diagram showing a mechanical configuration of a camera provided with an automatic film winding mechanism.

FIG. 3 is a schematic diagram showing an example of a mechanical film counter built in a camera having an automatic film winding mechanism.

FIG. 4 is a timing chart for explaining the operation of a camera having an automatic film winding mechanism.

FIG. 5 is a flowchart showing a control program used by a CPU for controlling a camera having an automatic film winding mechanism.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Film feed motor 2 Mechanical film counter 3 Signal falling detecting means 4 Delay sampling means 5 Control means 6 CPU 7 Camera frame 8 Film 9 Patrone 10 Film winding shaft 11 Sprocket hole 12 Contact member 13 Circuit board 14 Sprocket gear 15 Brush

Claims (2)

(57) [Scope of request for utility model registration] 1. A feed motor for winding and feeding a film having a sprocket hole formed therein, and a contact member which engages and interlocks with a moving sprocket hole and has chattering.
A mechanical film counter for sequentially outputting signals including the number of pulses corresponding to the feeding amount, a means for detecting at least a signal falling point at the trailing edge of each pulse , and a predetermined time exceeding chattering A delay sampling means for outputting a sampling signal with a delay from a signal falling point detected by the amount, and sequentially counting pulses according to the delay sampling signal to specify a final pulse corresponding to a preset feed amount. And a control means for controlling the feed motor in synchronism with the trailing edge of the signal of the last pulse to immediately stop feeding the film. 2. The control means includes means for setting a predetermined feed amount required for frame feed of a film, starting the feed motor at the start of frame feed, and synchronizing with a signal falling point of the last pulse. 2. A camera provided with an automatic film winding mechanism according to claim 1, further comprising driving means for braking the feed motor.