JPH10197816A - Optical scanning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust a beam convergence point on a scanning surface with high precision by continuously shifting the beam convergence point. SOLUTION: The optical scanning device consisting of a light source 1, a deflector 4, and an image forming lens 5 which forms an image on the scanning surface 6 has an optical glass unit 2 arranged between the light source 1 and scanning surface 6, and a convergence position adjusting means 7 which continuously adjusts the beam convergence position on the scanning surface 6 by continuously varying the thickness of the optical glass unit 2 along the optical axis is composed of a 1st adjusting means 7 which adjusts the length of the optical- axis directional length of the optical glass unit 2 in a storage space for a fluid medium having specific transmissivity and a specific refractive index.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning device used for an image recording device such as a laser printer or a digital copying machine, and more particularly to an optical scanning device comprising a light source, a deflector and an imaging lens for forming an image on a scanning surface. In the scanning device, an optical glass unit is provided between the light source and the scanning surface, and the thickness of the optical glass unit in the optical axis direction of the transparent medium is continuously changed to focus the beam on the scanning surface. The present invention relates to an optical scanning device including a focusing position adjusting means for continuously adjusting a position, continuously changing a beam focusing position on the scanning surface, and realizing highly accurate adjustment of the beam focusing position.

[0002]

2. Description of the Related Art A conventional optical scanning apparatus comprises a plurality of glass plates G having different thicknesses or different refractive indices between a light source LP and a collimator lens C, a deflector T and an imaging lens L as shown in FIG. And adjusts the convergence position of the beam on the scanning plane P.

[0003]

In the above-mentioned conventional optical scanning device, a plurality of glass plates G having different thicknesses or different refractive indexes are arranged between the light source LP and the scanning plane P as shown in FIG. To adjust the beam focusing position,
Since the thickness or the refractive index of the glass plate G changes stepwise, the focusing position of the beam can be adjusted only discontinuously and stepwise as shown in FIG. There is a problem in that the adjustment accuracy of the focusing position is adversely affected, and it is impossible to increase the accuracy.

Further, in order to increase the accuracy of the conventional optical scanning device, it is necessary to increase the number of different types of glass having different refractive indexes or different plate thicknesses, which leads to an increase in size and cost of the device. was there.

Accordingly, the present inventors have developed an optical scanning device comprising a light source, a deflector, and an imaging lens for forming an image on a scanning surface, in an optical glass unit disposed between the light source and the scanning surface. Focusing on the technical idea of the present invention that continuously adjusts the beam focusing position on the scanning surface by continuously changing the thickness in the optical axis direction, and as a result of further research and development, the scanning The present invention has been achieved to achieve the object of continuously changing the beam focusing position on the surface and realizing highly accurate adjustment of the beam focusing position.

[0006]

According to a first aspect of the present invention, there is provided an optical scanning apparatus comprising a light source, a deflector, and an imaging lens for forming an image on a scanning surface. An optical glass unit is provided between the light source and the scanning surface, and the thickness of the optical glass unit in the optical axis direction of the transparent medium is continuously changed so that a beam focusing position on the scanning surface is continuously changed. Focusing position adjusting means for adjusting the focusing position.

In the optical scanning device according to the present invention (the second invention according to the second aspect), in the first invention, the focusing position adjusting means may include a space for accommodating a fluid medium having a predetermined transmittance and refractive index. The optical glass unit is constituted by first adjusting means for adjusting the length in the optical axis direction.

According to a third aspect of the present invention, in the optical scanning apparatus according to the first aspect, the focusing position adjusting means may include a solid medium having a predetermined transmittance and a predetermined refractive index. It is constituted by second adjusting means for adjusting the length of the unit in the optical axis direction.

According to a fourth aspect of the present invention, in the optical scanning device according to the second aspect, the first adjusting means may be configured so that the first adjusting means is arranged so that the fluid is accommodated in a housing container forming the housing space. The container is constituted by container length adjusting means for adjusting the amount of the medium to be accommodated and adjusting the length of the optical glass unit of the container in the optical axis direction.

[0010] In the optical scanning device according to the present invention (fifth invention according to claim 5), in the third invention, the second adjusting means may be arranged so that the second adjusting means has a predetermined angle with respect to the optical axis direction of the optical glass unit. The solid medium having an inclined surface that is inclined at,
The thickness of the solid medium is adjusted by moving the solid medium in a direction intersecting the optical axis.

[0011]

According to the first aspect of the present invention, there is provided an optical scanning apparatus comprising a light source, a deflector, and an imaging lens for forming an image on a scanning surface. Since the thickness of the optical glass unit provided between the light source and the scanning surface is continuously changed in the optical axis direction of the transparent medium, the beam focusing position on the scanning surface is continuously adjusted. In addition, there is an effect that a highly accurate adjustment of the beam focusing position is realized.

In the optical scanning device of the second invention having the above-mentioned structure, in the first invention, the first adjusting means constituting the convergence position adjusting means may be a fluid medium having a predetermined transmittance and refractive index. Since the length of the accommodation space in the optical axis direction of the optical glass unit is adjusted, there is an effect that the beam focusing position on the scanning surface is continuously adjusted and the beam focusing position is highly accurately adjusted. Things.

[0013] In the optical scanning apparatus according to a third aspect of the present invention, in the first aspect, the second adjusting means constituting the convergence position adjusting means may be a solid medium having a predetermined transmittance and refractive index. Since the length of the optical glass unit in the optical axis direction is adjusted, it is possible to continuously adjust the beam focusing position on the scanning surface, and to achieve an effect of realizing highly accurate adjustment of the beam focusing position. .

According to a fourth aspect of the present invention, in the optical scanning device according to the second aspect of the present invention, the container length adjusting means constituting the first adjusting means is accommodated in an accommodation container constituting the accommodation space. Since the accommodation amount of the fluid medium is adjusted and the length of the optical glass unit of the accommodation container in the optical axis direction is adjusted, the beam focusing position can be quickly moved to an arbitrary position on the scanning surface by sucking and discharging the fluid medium. This has the effect of being able to adjust the distance.

According to a fifth aspect of the present invention, in the optical scanning apparatus according to the third aspect, the thickness adjusting means constituting the second adjusting means is arranged such that the thickness adjusting means is arranged in a predetermined direction with respect to the optical axis direction of the optical glass unit. The thickness of the solid medium is adjusted by moving the solid medium having an inclined surface inclined at an angle in a direction intersecting the optical axis. It is possible to adjust the beam focusing position to an arbitrary position.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention are described below.
This will be described with reference to the drawings.

(First Embodiment) As shown in FIGS. 1 and 2, the optical scanning device of the first embodiment includes a light source 1, a deflector 4, and an imaging lens 5 for forming an image on a scanning surface 6. In the optical scanning device, an optical glass unit 2 is disposed between the light source 1 and the scanning surface 6, and the thickness of the optical glass unit 2 in the optical axis direction is continuously changed, so that the scanning surface 6 Focusing position adjusting means 7 for continuously adjusting the upper beam focusing position adjusts the length of the accommodation space for the transparent fluid medium 12 having a predetermined transmittance and refractive index in the optical axis direction of the optical glass unit 2. This is constituted by a first adjusting means 71 that performs the adjustment.

As shown in FIG. 1, the light source 1 is constituted by a semiconductor laser 10 for irradiating a laser beam, and irradiates the optical glass unit 2.

As shown in FIG. 2, the optical glass unit 2 includes a hollow cylindrical body 20 having openings 201 and 202 formed at both ends for passing the laser beam from the semiconductor laser 10, and the hollow cylindrical body 20. 20, a transparent first glass plate 22 on a disk having a sufficient thickness to come into contact with the coil spring 21, and one end of the hollow cylindrical body 20. It comprises a transparent second glass plate 23 on a disk, and a storage container 24 as a storage space for the fluid medium 10 between the first and second glass plates 22, 23.

The first adjusting means 71 adjusts the accommodation amount of the fluid medium 12 accommodated in the accommodation container 24 forming the accommodation space, and adjusts the accommodation amount of the fluid medium 12 in the optical axis direction of the optical glass unit of the accommodation container. Length adjusting means 7 for adjusting the length of the container
11.

The container length adjusting means 711 is provided in the storage container 24 formed as a storage space between the first and second glass plates 22 and 23 and has a predetermined transmittance and a predetermined refractive index. A pump 712 for supplying and discharging the fluid medium 12 and a suction / discharge switching valve (not shown) are provided. The deformation of the coil spring 21 accommodates the fluid medium 12 in the optical axis direction of the optical glass unit 2. The axial length (l in FIG. 2) of the storage container 24 is configured to be continuously controlled.

Between the optical glass unit 2 and the deflector 4, a collimator lens 3 for converting a laser beam passing through the optical glass unit 2 into a parallel light beam and supplying the parallel light beam to the deflector 4 is arranged. Has been established.

The deflector 4 has a large number of flat reflecting surfaces formed on the outer peripheral wall of the rotating polygonal column, and deflects the direction of the parallel light beam from the deflector 4 to supply it to the imaging lens 5. It is configured as follows.

The imaging lens 5 is disposed between the deflector 4 and the scanning surface 6 and is configured to form an image on the scanning surface 6.

The scanning surface 6 is constituted by a photosensitive drum 60, and the photosensitive drum 60
Are formed on the photosensitive surface formed by the outer peripheral wall of the light emitting element.

That is, the principle of continuously adjusting the beam convergence position on the scanning surface 6 in the convergence position adjusting means 7 of the first embodiment will be described with reference to FIG.

As shown in FIG. 3, the displacement Δx of the imaging position caused by inserting a transparent object C having a refractive index n and a thickness d between the image plane 1P (object plane-scanning plane) and the lens 1L. Can be represented by the following equation. Δx = d (1-1 / n)

As is clear from the above equation, it can be easily understood that by continuously changing the thickness of the object C, the image forming position can also be continuously changed.

In the first embodiment, the pump 7
By controlling the inflow amount and outflow amount of the fluid medium in the storage container 24 by the intake and exhaust valves 12 and the suction valve, the image forming position (beam (Convergence position) can be continuously changed.

In the optical scanning device of the first embodiment having the above configuration, as shown in FIGS. 1 and 2, the semiconductor laser 10 constituting the light source 1 is provided with the coil spring of the optical glass unit 2. One opening 2 provided
01 is irradiated with a laser beam.

The supply and discharge of the fluid medium having a predetermined transmittance and refractive index to and from the container 24 are performed by the pump 712 and the suction / discharge switching valve (not shown) constituting the container length adjusting means 711. By controlling the deformation of the coil spring 21, the axial length l of the storage container 24 that stores the fluid medium 12 in the optical axis direction of the optical glass unit 2 is continuously controlled.

Therefore, the laser beam applied to one opening 201 of the optical glass unit 2 has an axial length of the container 24 in which the fluid medium 12 having a predetermined transmittance and refractive index is accommodated. 1 and is supplied to the collimator lens 3 through the other opening 202.

The laser light refracted after passing through the optical glass unit 2 is converted into a parallel light beam by the collimator lens 3 disposed between the optical glass unit 2 and the deflector 4. It is supplied to the deflector 4.

The deflector 4 deflects the direction of the parallel light beam from the deflector 4 by a plurality of flat reflecting surfaces formed on the outer peripheral wall of the rotating polygonal column, and deflects the light to the imaging lens 5. Supply.

The imaging lens 5 disposed between the deflector 4 and the scanning plane 6 focuses the parallel light beam whose direction is deflected by the deflector 4 on the scanning plane 6. Focus on the position.

The scanning surface 6 is provided on the optical glass unit 2
Based on the laser light refracted according to the length 1 of the storage container 24, the imaging lens 5 moves a beam focusing position corresponding to the refraction on a photosensitive surface formed by the outer peripheral wall of the photosensitive drum 60 by the imaging lens 5. It is imaged.

In the optical scanning device according to the first embodiment having the above-described operation, the first adjusting means 71 constituting the convergence position adjusting means 7 is disposed between the light source 1 and the scanning surface 6. As the length of the optical glass unit 2 in the optical axis direction of the accommodation space for the fluid medium 12 having the predetermined transmittance and refractive index of the optical glass unit 2 is continuously adjusted, as shown in FIG. This has the effect of continuously adjusting the beam convergence position on the scanning surface 6 and realizing highly accurate adjustment of the beam convergence position.

In the optical scanning device of the first embodiment, the container length adjusting means 71 constituting the first adjusting means is
The amount of the fluid medium 12 accommodated in the accommodation container 24 that constitutes the accommodation space is adjusted to adjust the length of the optical glass unit 2 of the accommodation container 24 in the optical axis direction. When the medium 12 is sucked and discharged,
This has the effect that the beam focusing position can be quickly adjusted to an arbitrary position above.

Further, in the optical scanning device of the first embodiment, the supply and discharge of the fluid medium 12 to and from the storage container 24 are controlled by the pump 712.
The degree of freedom of installation of the pump 712 is high, and the empty space in the optical scanning device can be effectively used, and the optical glass unit itself can be downsized.

(Second Embodiment) In the optical scanning device of the second embodiment, as shown in FIGS. 5 and 6, the focusing position adjusting means 7 is a transparent solid object having a predetermined transmittance and a predetermined refractive index. The difference from the first embodiment is that the medium 721 is constituted by a second adjusting means 72 for adjusting the length of the optical glass unit in the optical axis direction of the optical glass unit. Will be described.

The second adjusting means 72 includes a movable first solid medium 721 having an inclined surface 723 inclined at a predetermined angle with respect to the optical axis direction of the optical glass unit 2.
Is moved in a horizontal direction inclined with respect to the optical axis, thereby comprising a thickness adjusting means 720 for adjusting the thickness of the solid medium 721.

The first solid medium 721 is made of a transparent glass member having a predetermined transmittance and refractive index in the form of a right-angled isosceles triangle, and has an input surface 725 perpendicular to the optical axis direction of the optical glass unit 2. And the inclination angle θ with respect to the optical axis.
And an output surface formed of a 45-degree inclined surface 723 (cut surface).

The second solid medium 722 includes an inclined surface 724 which is opposed to the inclined surface of the first solid medium 721.
It is formed of a substantially trapezoidal transparent glass member having a predetermined transmittance and refractive index on which a (cut surface) is formed, and the longitudinal axis of the transparent glass member is aligned with the optical axis of the optical glass unit 2. .

On the lower surface of the first solid medium 721, a rack 726 is formed, and a motor 72 as a drive source is formed.
By rotating a pinion 728 disposed at the tip of the shaft of No. 7, it is configured to move laterally along the inclined surfaces 723 and 724.

The optical scanning device according to the second embodiment having the above-described configuration, as is apparent from FIG. 6, rotates the pinion 728 by the rotation of the motor 727 as a driving source, thereby causing the first scanning through the rack. Of the optical glass unit 2 in the optical axis direction according to the amount of movement of the solid medium 721 in the lateral direction along the inclined surface.
Is continuously changed.

Therefore, the length l of the container 24 of the optical glass unit 2 is the same as in the first embodiment.
Based on the laser light refracted according to the above, an image is formed by the imaging lens 5 at a beam focusing position corresponding to the refraction on the photosensitive surface formed by the outer peripheral wall of the photosensitive drum 60.

In the optical scanning apparatus according to the second embodiment having the above-described operation, the second adjusting means 72 constituting the focusing position adjusting means 7 is a solid medium having a predetermined transmittance and a predetermined refractive index. Since the length of the unit 2 in the optical axis direction is adjusted, the beam focusing position on the scanning surface 6 is continuously adjusted as shown in FIG. 4 and the beam focusing position is adjusted with high accuracy. It is effective.

Further, in the optical scanning device according to the second embodiment, the thickness adjusting means 720 constituting the second adjusting means 72
Is a solid medium 721 having an inclined surface inclined at a predetermined angle with respect to the optical axis direction of the optical glass unit 2.
Is moved in the lateral direction inclined with respect to the optical axis, thereby adjusting the thickness of the solid medium in the optical axis direction. Therefore, the beam focusing position can be changed to an arbitrary position on the scanning surface 6 by a simple mechanism. Can be adjusted.

Further, the optical scanning device of the second embodiment may use only two glasses of the first and second solid media 721 and 722. This has the effect of enabling downsizing and cost reduction.

The above-described embodiments have been described by way of example only, and the present invention is not limited to these embodiments. Those skilled in the art will recognize from the claims, the detailed description of the invention, and the drawings. Modifications and additions are possible without departing from the technical idea of the present invention.

In the first embodiment, as an example, the housing in which the fluid medium 12 is formed between the first and second glass plates 22 and 23 against the urging force by the coil spring 21 is housed. An example has been described in which the axial length (l in FIG. 2) of the optical glass unit 2 in the optical axis direction of the container 24 is continuously controlled. However, the present invention is not limited thereto, and An embodiment in which a coil spring as shown in FIG. 7 is changed to a hollow cylindrical body made of a soft elastic material such as rubber can be adopted.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an optical scanning device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an optical glass unit and a focusing position adjusting unit according to the first embodiment.

FIG. 3 is an explanatory diagram illustrating a principle of adjusting a beam convergence position on a scanning surface according to the first embodiment.

FIG. 4 is a diagram showing a relationship between a thickness of an optical glass unit and a beam focusing position in the first embodiment.

FIG. 5 is a perspective view illustrating a main part of an optical scanning device according to a second embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a principle of movement of a solid medium and thickness adjustment by a thickness adjusting means in the second embodiment.

FIG. 7 is a sectional view showing a main part of another embodiment of the present invention.

FIG. 8 is a perspective view showing a conventional optical scanning device.

FIG. 9 is a diagram showing a relationship between a thickness of an optical glass unit and a beam focusing position in the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source 2 Optical glass unit 4 Deflector 5 Imaging lens 6 Scanning surface 7 Focusing position adjusting means 12 Fluid medium 71 First adjusting means

Claims (5)

[Claims] 1. An optical scanning device comprising a light source, a deflector and an imaging lens for forming an image on a scanning surface, wherein an optical glass unit is disposed between the light source and the scanning surface. An optical scanning device comprising a focus position adjusting means for continuously changing a thickness of a transparent medium in an optical axis direction and continuously adjusting a beam focus position on the scanning surface. 2. The first adjusting device according to claim 1, wherein the focusing position adjusting means adjusts a length of the accommodation space of the fluid medium having a predetermined transmittance and a refractive index in the optical axis direction of the optical glass unit. An optical scanning device characterized by being constituted by means. 3. The focusing position adjusting means according to claim 1, wherein the focusing position adjusting means is constituted by a second adjusting means for adjusting a length of the solid glass having a predetermined transmittance and a refractive index in the optical axis direction of the optical glass unit. An optical scanning device, comprising: 4. The storage medium according to claim 2, wherein the first adjusting unit adjusts a storage amount of the fluid medium stored in a storage container forming the storage space,
An optical scanning device comprising a container length adjusting means for adjusting the length of the optical glass unit of the storage container in the optical axis direction. 5. The solid-state medium according to claim 3, wherein the second adjusting unit is configured to move the solid medium having an inclined surface inclined at a predetermined angle with respect to an optical axis direction of the optical glass unit to an optical axis. An optical scanning device comprising a thickness adjusting means for adjusting the thickness of the solid medium by moving the solid medium in a direction intersecting with the optical medium.