JPH0659332A - Camera with film meandering preventing mechanism - Google Patents

Abstract

PURPOSE:To prevent a film from being deviated in a width direction when it is fed. CONSTITUTION:A guide roller 15 is provided near a magnetic head 21 on a film path 8. Besides, flanges 16 provided with a conical surface 17 are formed on both ends of the roller 15. Since the side edge 3a of the film 3 is returned to a central part side in the width direction due to the inclination of the surface 17, the film 3 is prevented from meandering. Therefore, the loss of an azimuth can be minimized and the malfunction of the magnetic head can be prevented from occurring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera which prevents the film from meandering and blurring in the width direction when the film is run.

[0002]

2. Description of the Related Art A camera using a film having a magnetic recording layer is known, for example, in International Publication WO 90/04201 and WO 90/04202. This camera reads data such as film type and film sensitivity from the magnetic recording layer applied to the film and provides the data for photographing, or writes the photographing data in the magnetic recording layer.

[0003]

By the way, since the width of the film guide of the camera in the width direction is usually about 0.1 mm on one side, the film can be fed at a maximum of 0.2 mm in the width direction.
mm meander. If the position of the magnetic head is fixed with the film guide as a reference, the center of the recording / reproducing track of the magnetic head is displaced by up to ± 0.1 mm due to the meandering of the film.

Further, it is known that when the gap during reproduction has an angle (azimuth) error of θ from the track width direction with respect to during recording, the reproduction output is attenuated according to the following formula 1.

[0005]

[Equation 1] This is generally called azimuth loss.

Here, “λ” is a recording wavelength, and assuming that the recording density is 1000 BPI and the recording method is the tribit method, λ = 25.4 mm / (1000 × 1/3) =
It is 8.5μ. W is a track width, which is 1 mm. Further, θ is the inclination in the camera as shown in FIG. 7, and in the maximum case, tan ⁻¹ (0.7 / 50) =
It becomes 0.8 °. However, the width D _{1 of the} film 80 is 35.00 (−0.1 to +0) mm as an initial value standard, but it may be 34.5 mm min due to changes over time, etc.
4.5 mm. The width D ₂ of the film passage in the film width direction is 35.00 (−0 to +0.2) mm, and the length D ₃ in the feeding direction is 50 mm. In addition, reference numeral 8 in the drawing
Reference numeral 1 is an aperture, and reference numeral 82 is a magnetic head.

When the azimuth loss is calculated from the fluctuation of the film position in the current camera according to the equation 1, Lθ =
It becomes 15.3 dB. Generally, in a digital magnetic recording system, it is said that S / N ≧ 30 dB is required in terms of reliability, but the occurrence of this azimuth loss indicates that reliability is significantly impaired.

The film meandering and the azimuth loss as described above have a problem that the reproduction information is left unerased at the time of reproduction output reduction or overwriting, and becomes a noise during reproduction, which is a major cause of malfunction.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a camera with a film meandering prevention mechanism which prevents the film from being transferred while being displaced in the width direction. And

[0010]

In order to achieve the above object, the present invention provides a film guide roller in a film passage, and the film guide roller is provided with a conical flange for guiding both side edges of the film. It is provided.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 2 to 4 showing the essential parts of a camera of the present invention.
In the camera body 2, an aperture 4 which defines an exposure range for the film 3 is formed, and inner rails 6a and 6b for positioning the film 3 in the optical axis direction are formed above and below the aperture plate 4 with the film pressure plate 5. Further, on the outer side thereof, outer rails 7a, 7 which regulate the position in the film width direction are provided.
b is formed.

Further, as shown in FIG. 2, the inner rails 6a,
On both sides of the film passage 8 composed of 6b and the outer rails 7a and 7b, a cartridge storage chamber 9 is provided on one side and a film winding chamber 11 is provided on the other side. The film winding chamber 11 is provided with a winding shaft 11a for winding the film 3. A cartridge 10 in which the film 3 is wound and stored is loaded in the cartridge storage chamber 9, and the spool 10a of the cartridge 10 has a spool rotation shaft 1 of the camera.
Two are adapted to engage.

In the film passage 8 between the aperture 4 and the film winding chamber 11, a film guide roller 15 is rotatably provided. As shown in FIG. 1, the film guide roller 15 has conical surface-shaped flanges 16 at both ends. When the side edge 3a of the film 3 contacts the conical surface 17 of the flange 16, the inclination of the conical surface 17 causes the film 3 to approach the central portion side in the width direction, thereby preventing the film 3 from meandering. .

A recess 20 having an arcuate cross section is formed between the film guide roller 15 and the aperture 4. The recess 20 serves as an escape portion for the film 3 when the magnetic head 21 described later presses the film 3 so as to be in close contact with the film 3.

As shown in FIG. 3, the film pressure plate 5 is attached to the back cover 25 via a spring plate 26.
A magnetic head 21 is fixed to the film pressure plate 5 at a position corresponding to the recess 20. As shown in FIG. 4, the magnetic head 21 has its head surface 21a in contact with the magnetic recording layer 23 coated in stripes on the base surface side of the film 3 to write and read digital data. The data read from the film 3 includes, for example, the type of film, the film sensitivity, and the number of frames to be photographed. The data written to the film 3 is the data indicating the photographing condition,
For example, there are subject temperature, brightness, contrast, shooting distance, strobe light amount, shutter speed, aperture, and the like. Further, the magnetic recording layer 23 is not limited to a striped one,
It may be a transparent magnetic recording layer coated on the entire base surface of the film 3.

Further, as shown in FIG. 5, a substrate 28 is attached to the film pressure plate 5 in addition to the magnetic head 21, and the film pressure plate 5 is a magnetic recording / reproducing unit by itself. On the substrate 28, a head driver IC for driving the magnetic head 21, a reproducing amplifier IC, a main C for controlling modulation / demodulation, a recording / reproducing sequence, and the like.
PU etc. (not shown) are mounted.

The operation of the camera of the present invention constructed as above will be described. As shown in FIG. 2, when the back cover of the camera is opened and the tip of the leader of the film 3 is pulled out from the cartridge 10 onto the winding shaft 11a of the film winding chamber 11 and the back cover is closed, the outer rails 7a, The film 3 is set between 7b. At this time, as shown in FIG. 1, the film 3 is restricted from moving in the film width direction by the flanges 16 at both ends of the guide roller 15. Even when the film 3 is likely to meander, as shown in FIG.
Since the film 3 is returned to the central portion side in the width direction by the inclination of the conical surface 17, the meandering is prevented.

As a result, the positional relationship between the head surface 21a of the magnetic head 21 and the magnetic recording layer 23 of the film 3 is always maintained constant. As a result, not only is track deviation prevented, but since the film 3 does not tilt in the film passage 8, so-called azimuth loss is extremely reduced, and a reproduced signal without noise can be obtained.

Although the above-described embodiment is a film meandering prevention device for magnetic recording, in addition to this, a character string or a bar code representing a photographing date or photographing data, for example, within the photographing screen or close to the photographing screen. Even in the case of optically imprinting the like, if the meandering of the film is prevented by implementing the present invention, the recorded character string or bar code will not be vertically displaced.

[0020]

As described above, according to the present invention,
Since the film guide rollers are provided in the film passage and the flanges having the conical surface are formed at both ends of the guide rollers, the flanges prevent the film from meandering.
Therefore, in a camera with a built-in magnetic head, by disposing the magnetic head near the film guide roller, the azimuth loss can be minimized and writing mistakes and reading mistakes can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of a camera embodying the present invention.

FIG. 2 is a front view showing a state where a back cover of the camera is removed.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is an enlarged sectional view showing a magnetic head and a guide roller.

FIG. 6 is a sectional view showing a relationship between a film and a guide roller.

FIG. 7 is a schematic plan view showing a relationship between a film and a magnetic head in a conventional camera.

[Explanation of symbols]

 3 Film 5 Pressure Plate 7a, 7b Outer Rail 8 Film Passage 10 Patrone 15 Film Guide Roller 16 Flange 17 Conical Surface

Claims (2)

[Claims] 1. A camera with a film meandering prevention mechanism, wherein a film guide roller is provided in the middle of a film passage, and the film guide roller is provided with conical flanges for guiding both side edges of the film. . 2. A magnetic head for contacting a magnetic recording layer formed on the film to perform magnetic recording / reproduction near the film guide roller.
A camera with the described film meandering prevention mechanism.