JP2650231B2 - Ray / deflecting device - Google Patents

Description

The present invention is a device for deflecting a light beam, comprising at least one prism, said prism having at least one reflecting surface, and having a rotational movement about an axis of rotation. It relates to the type that is supported as much as possible.

The light beam / deflecting device is used, for example, in a scanning mechanism for an original image / scanning device or a recording mechanism for a recording device.

In an original scanning device, also referred to as an input scanner, a light beam generated in a scanning mechanism is guided pixel by pixel and in a scanning line through the original to be scanned, and reflected or transmitted through the original. Light is converted to an image signal in a photoelectric converter. In a recording device, also called a recorder, an exposure device or an output scanner, the light beam obtained in the recording mechanism is intensity-modulated by an image signal to record information, and is sensitive to light on a pixel-by-pixel and scanning line basis. Guided through the recording material to be printed.

In the case of the flat-type device, the carrier for the original or the recording material is a flat surface, through which the light rays are guided pixel by pixel and in a scanning line, and this flat surface is , Relative to the scanning mechanism or the recording mechanism. In the case of the inner drum type device, the carrier for the original or recording material is configured as a stationary half-shell or trough. The scanning or recording mechanism moves parallel to the longitudinal axis of the half shell or trough, and the light beam is guided through the original or recording material in a radial direction perpendicular to the longitudinal axis.

A beam-deflecting device of this type with a prism is known from DE 3918075. The incoming light rays are in this case first introduced into the prism via the light entry surface and are reflected inwardly in the area of the exit surface. Then, the light is reflected once again on another reflecting surface, and is refracted when the light beam advances from the prism. The prism has an asymmetric mass distribution about the axis of rotation, which permits only a limited rotational speed range due to the centrifugal force generated when the beam / deflector rotates. Due to the asymmetric shape given about the axis of rotation, furthermore, at relatively high rotational speeds, turbulence of the air occurs, which is a source of noise and dirt. It may be.

Another beam and deflection device with a prism is U.S. Pat.
It is known based on the specification of 78720. Even in this known configuration, the prism has a mass distribution and shape about the axis of rotation, which gives rise to considerable asymmetric centrifugal forces and noise.

It is an object of the present invention to improve a beam / deflecting device of the type mentioned at the outset and to provide a beam / deflecting device whose operation at high rpm is guaranteed.

In order to solve this problem, in the configuration of the present invention, the prism is held by a support that is in contact with its reflection surface, and the prism and the support as a whole have an outer contour that is rotationally symmetric about the rotation axis. And a symmetrical mass distribution, and the reflecting surface has an inclination angle of about 45 ° with respect to the ray entering direction.

With the configuration according to the present invention, that is, since the prism and the support have an outer contour that is rotationally symmetric about the rotation axis as a whole, air turbulence that causes a problem is caused. It is possible to rotate the device at high rotational speeds without generating a flow, that is, a turbulent flow that may obstruct the ray path. In addition, such an outer contour not only helps to avoid the generation of loud noises, but also avoids contamination of the prism by airborne particles contained in the air flowing around the prism.

In addition, since the prism and the support have a symmetric mass distribution as in the present invention, it is possible to avoid, in particular, the vibration and the swing generated due to the resonance effect.

Another advantageous configuration of the invention is that the prism is configured in a hemispherical shape and the support holding the prism is configured in a substantially hemispherical shape.

In a further advantageous embodiment of the invention, the prism has a light entry surface which is chamfered and formed flat. The size of the chamfered light entrance surface can be adjusted to the beam diameter of the light beam entering the prism. In addition to making the light entrance surface flat, it is also possible to provide a light entrance portion having a concave curved portion curved toward the reflection surface.

In the following, advantageous embodiments of the invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view, partially broken away, of a device in which a hemispherically configured prism is arranged in the region of a substantially hemispherical support.

FIG. 2 is a longitudinal sectional view showing an embodiment in which a hemispherical prism has a light entrance surface curved inward.

FIG. 3 is a diagram showing an example of use of the light beam / deflecting device according to the present invention.

FIG. 1 shows the device for deflecting the light beam partially broken away. The device mainly consists of a prism 1 which is mounted for rotation about an axis of rotation 2 and has an outer contour 3 which is at least partially rounded. First
In the embodiment shown, the prism 1 is configured in a hemispherical shape with a reflecting surface 5. The reflecting surface 5 is arranged in the range of the limiting portion of the prism 5 on the support 6 side. In the range of extension on the opposite side to the reflection surface 5, the prism 5
The entry surface 7 extends substantially perpendicular to the entry direction 8 of the light beam 9.

The reflection surface 5 is arranged to be inclined with respect to the approaching direction 8, in which case the inclination angle is about 45 °. The light rays 9 are thereby reflected at an angle of about 90 ° with respect to the entry direction 8 and exit the prism 1 in the entry direction 11 through the light entry surface 10. The light exit surface 10 is configured to be substantially curved.

The support 6 has a substantially hemispherical shape and the prism 1
To form a rotationally symmetric object with respect to the rotation axis 2. In particular, when the support pair 6 and the prism 1 are made of materials having the same specific gravity, a symmetrical mass distribution can be realized. If different materials are used, it is advantageous if both materials have at least the same coefficient of thermal expansion, so that the area of the transition joining the prism 1 with the support 6, for example a glue Can be avoided.

The support 6 is gripped in its partial area by a holder 12, which has a substantially bucket-shaped configuration. The support 12 is connected to a shaft 13 in the area of the extension opposite the support 6, which connects the support 12 to a rotary drive (not shown).

In addition to the construction of the prism 1 in the form of a hemisphere, it is in principle also possible to provide another round configuration of the prism. In particular, it is possible to provide an arrangement corresponding to, for example, a cylindrical segment about the axis of rotation 2, and to supplement the cylindrical contour with the support 6. Furthermore, it is also possible for the holding body 12 and the support 6 to be manufactured from a uniform material and for example to be integrated.

In the embodiment shown in FIG. 2, the light entrance surface 7 is provided with a concave curved portion. With this, it is possible to produce a lens effect, and by this lens effect,
It cancels out the lens effect due to the curved configuration of the light exit surface 10 or, together with another lens effect, gives rise to a predeterminable beam focusing. Instead of a curved light entry surface 7, it is also possible to arrange a separate lens in the region of the substantially flat light entry surface 7. By the round configuration of the outer contour 3,
Especially when the prism 1 is formed in a hemispherical shape,
It is possible to realize a high rotation speed. In order to match the temperature coefficients of the support 6 and the prism 1, it is possible in particular to manufacture the support 6 from ceramic or from a special alloy. When the support 6 is made of the same material as the material of the prism 1, it is possible to provide, for example, a dielectric reflective layer on the reflective surface 5. When the prism 1 and the support 6 are made of different materials,
The reflection properties based on the material transition can be used to realize the reflection surface 5.

FIG. 3 shows an example in which the light beam / deflecting device according to the present invention is used in a scanning device of a recording device constructed based on the principle of the inner drum. In such an inner drum recorder or inner drum exposure device, the recording material
Reference numeral 15 is fixed to an inner wall of a holding member 16 having a half shell shape or a cylindrical segment shape. The scanning device rotates about the longitudinal axis 17 of the half-shell or cylindrical segment. The scanning device has a beam and deflection device as shown and described in FIG.

Claims (9)

(57) [Claims] 1. A device for deflecting a light beam, comprising at least one prism, said prism having at least one reflecting surface and being mounted for rotational movement about an axis of rotation. In the form, the prism (1) has a support (6) in contact with its reflecting surface (5).
, The prism (1) and the support (6) as a whole have an outer contour that is rotationally symmetric about the axis of rotation (2) and at the same time have a symmetric mass distribution. A light-deflecting device, characterized in that the reflecting surface (5) has a tilt angle of approximately 45 ° with respect to the entering direction (8) of the light beam (9). 2. The light beam / deflecting device according to claim 1, wherein the prism has a hemispherical shape. 3. A support (6) for holding a prism (1).
3. The light beam / deflecting device according to claim 1, wherein the light beam / deflecting device has a substantially hemispherical shape. 4. The prism (1) according to claim 1, wherein the prism (1) is provided with a light entry surface (7) formed by chamfering the flat surface.
The light beam / deflecting device according to any one of the above items. 5. The light beam / deflecting device according to claim 1, wherein the light entrance surface has a concave curved portion curved toward the reflection surface. . 6. The support (6) is at least partially received by a holder (12) configured substantially in the form of a bucket, the holder (12) being on the opposite side of the support (6). 6. The beam / deflecting device according to claim 1, which is connected to a shaft for transmitting rotational movement in the region of the extension of the beam. 7. The light beam / deflecting device according to claim 1, wherein the support (6) and the holder (12) are made of a uniform material. 8. The light beam / deflecting device according to claim 1, wherein the support and the prism have a temperature expansion coefficient substantially corresponding to each other. 9. The light beam / deflecting device according to claim 1, wherein a lens is arranged in a range of the light entrance surface.