JPS5944613B2 - Film holder front/back detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for detecting the front and back sides of a film holder used for loading film into a camera for photographing sheet film.

In a camera for sheet film photography, a film holder loaded with film on both sides is fixed in a predetermined position on the camera, a photograph is taken with the film loaded on one side of the film holder, and then the film holder is turned over and the camera is opened. and then take a second picture using the film loaded on the other side of the film router.

Because of this procedure, the user may forget to turn the film holder over when taking the second picture.

In this case, the first film is double-exposed, requiring the user to take the photograph again, and if the double exposure is not noticed during the photographing process, it will result in a serious photographic error. Furthermore, when the first film is taken and the film holder is removed from the camera, there is a risk of confusion as to which side of the film holder was exposed during the first film. An object of the present invention is to easily and reliably detect whether a film holder attached to a camera is on the front or back side, and to easily realize a device that can solve the above problems by detecting the front and back sides of the film holder. The present invention provides a device for detecting front and back sides of a film holder.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 1, a mounting base 1 fixes the film holder at the shooting position and also supports a window frame 2 for focusing.The window frame 2 is supported by a plate 3.
allows movement in the front and rear directions.

The window frame 2 is raised from the mounting base 1 by rotating the lever 4, and a film holder 5 shown in FIG. 2 is inserted into the gap.
In a sheet film photographing camera equipped with such a mechanism, the detection device of the present invention has a film holder 5 with a partial notch (the one shown in FIG. 2 is a hole) 6.

Further, when the film holder 5 is mounted on the mounting base 1, a lever switch 7 and a film holder 5, which are activated by pressing the end face of the film holder 5, are mounted with the notch 6 at the top (surface mounting). A lever switch 8 is provided which maintains an inoperable state due to the presence of the notch 6, and which is activated by being pressed by the end surface when the film holder 5 is mounted with the notch 6 at the bottom (back side mounting). . FIG. 3 shows the mounted state in which the film holder 5 is placed with its notch 6 facing upward, the lever switch r is actuated, and the lever switch 8 is
deactivate. FIG. 4 shows the film holder 5 mounted with its notch 6 facing downward, and lever switches R and 8 are both operated. Therefore, the lever switch r
detects the attachment of the film holder 15, and the lever switch 8 detects the difference between the front and back of the attachment surface of the film holder 15.

The detection signals of the lever switches 7 and 8 are input signals to the circuit shown in FIG. In FIG. 5, the operation of the lever switch 1 (installation of the film holder 5) is controlled by the inverter 9.
The input of the inverter 9 is set to "0".The inverter 9 opens the gates of the NAND gates 10 and 11 with its "1" output. Inverter 12 outputs 61゛ to NAND gate 1.
Set the input of 1 to 11".Nandgate 10 of 60"
The output lights up a light emitting element (for example, a light emitting diode) 13, and the '0' output of the NAND gate 11 lights up the light emitting element 14. Therefore, when the film holder 5 is not attached, neither the light emitting elements 13 nor 14 are lit, indicating that no film is loaded.

Furthermore, when the film holder 5 is mounted in the state shown in FIG.
3 can be turned on to indicate that the film holder 5 is mounted on the surface. Conversely, when the film holder 5 is mounted as shown in FIG. 4, the output of the Nando game opening 1 becomes "0" and the light emitting element 14 is turned on to indicate that the film holder 5 is mounted on the back side. By providing such a front/back detection device, it is possible to easily visually check whether the film holder 5 is mounted on the front side or the back side by the difference in the light emitting element that lights up, and it is possible to easily check whether the film holder 5 is mounted on the front side or the back side. It can also be determined whether the

In addition, as a mounting state detection mechanism for the film holder,
A simple device consisting of two microswitches and a notch in the film holder may be sufficient. A film holder front/back detection device having such features allows the photographer to recognize the mounting state of the film holder, prompts the photographer to turn the holder over when taking a second picture, and prevents double exposure.

Further, the invention can also be applied to a display device that displays which side of the film holder 1 has been exposed when the film holder 1 is removed from the camera after the first photograph has been taken. FIG. 6 shows a display device to which the detection device of the present invention is applied, and even if the film holder is removed at the end of the first shooting, the first mounting state is stored and displayed.

In FIG. 6, the reset flip-flop 15
stores the 60 output of the NAND gate 10 through the inverter 16, and continues to drive the light emitting element 13 with its Q output (゛O゛). Similarly, flip-flop 17 stores the output of NAND gate 11 through inverter 18, and its Q
The output continues to drive the light emitting element 14. In addition, the flip-flop 15, 1T glue set is connected to the inverter 18, 16.
or the output of the OR gates 20 and 21 by the switch 19 which is operated manually or in conjunction with the two shutter operations at the end of two shots. By adding such a memory circuit to the front/back side detection device, not only when the film holder 1 is in the mounted state, but also when the film holder 1 is removed from the mounted state, it is possible to check whether the previous mounting was performed on the front side or the back side. It is possible to display whether the film holder has been attached for the second time, and there is no need to be confused as to which side to attach the film holder to.If the display changes when the film holder is attached for the second time, it means that the attachment is normal. I understand.

In addition, in order to prevent forgetting to turn the film holder over when taking the second picture, the memory circuit shown in Fig. 6 can be used.
This can be realized by providing an alarm display means that sounds a buzzer or the like when a set input is applied again to the flip-flop side that is in the set state. As described above, the device for detecting both sides of a film holder according to the present invention has the effect of easily and reliably detecting the mounting state of a film holder.

[Brief explanation of the drawing]

FIGS. 1 and 2 are mechanical diagrams showing an embodiment of the front/back detection device for a film holder according to the present invention, FIGS. 3 and 4 are views showing the mounted state of the film holder, and FIG. FIG. 6 is a circuit diagram showing an embodiment of the display section according to the present invention, and FIG. 6 is a circuit diagram showing an example of application of the present invention. 1...Mounting base, 2...Window frame, 5...
. . . Film holder 1, 7, 8 . . . Rubber switch, 13, 14 . . . Light emitting element.

Claims (1)

[Claims] 1. In a film holder having sheet film on both the front and back sides, first and second lever switches provided near the film holder attachment position of a camera for sheet film photography, and the first lever switch when attached to the camera. a film holder having a notch that determines whether the second lever switch is activated or not depending on the front and back sides of the mounting surface; A device for detecting the front and back sides of a film holder, comprising means for displaying the front and back sides of the surface of the holder that is attached to a camera.