KR20060080359A - Apparatus for laser scannig - Google Patents

Abstract

A tandem optical scanning device is disclosed. Gwangju presidential device according to the present invention includes a light source unit mounted on a circuit board, a rotating multi-face mirror for deflecting and reflecting laser light from the light source, and an optical frame containing these optical components, The angle θ1 formed by the circuit board and the angle θ2 at which the laser light emitted from the light source is rotated are different from each other. According to this, miniaturization of the optical scanning device can be pursued.

Optical scanning device, circuit board, laser diode, predetermined angle, rotating mirror

Description

Optical scanning device {Apparatus for laser scannig}

1 is a configuration of the optical scanning device according to the prior art,

2 is a cross-sectional view of the light source unit of FIG.

3 is a block diagram of an optical scanning device according to an embodiment of the present invention,

4 is a plan view of the light source unit of FIG.

5 is a block diagram of a tandem optical scanning device according to an embodiment of the present invention.

<Description of Major Symbols in Drawing>

200. Optical scanning device 201. Optical frame

210. Light source unit 211. Laser diode

212.Circuit Board 214.Laser Holder

216. Collimating Lens 220. Rotating Polyscope

250. Imaging Lens 270. Reflection Mirror

The present invention relates to an image forming apparatus, and more particularly, to a tandem optical scanning device used in a color image forming apparatus.

Electrophotographic image forming apparatuses, such as laser beam printers, color digital copiers, and color digital scanners, irradiate a laser beam onto a photosensitive medium charged at a constant potential to form an electrostatic latent image on the photosensitive medium. It is provided.

1 and 2 are related to the conventional optical scanning device, the light source unit 110, the cylindrical lens 120, the rotating polygon mirror 130, the imaging lens (F-θ lens, 150) and the reflection mirror 160 It includes. The optical parts are installed to be supported by the optical frame 101.

The light source unit 110 includes a circuit board 112 having a laser diode 111 as a light source, an IC (not shown) for driving the laser diode 111, and the like. The circuit board 112 is fastened to the laser holder 114 by a screw 113. Meanwhile, the semiconductor laser 111 of the light source unit 110 is installed perpendicular to the circuit board 112. The collimating lens 116 makes the laser light emitted from the laser diode 111 into parallel light and is fixed inside the lens barrel 117. The lens barrel 117 is formed with an optical stop 118 that forms an image of laser light in a desired size. The lens barrel 117 is mounted to the laser holder 114 by an adhesive.

The laser light emitted from the light source unit 110 mounted on the optical frame 101 is condensed on the reflective surface of the rotating polygon mirror 130 by the cylindrical lens 120.

The rotating polygon mirror 130 rotates at a high speed by the driving motor 140 and reflects the laser light at a constant speed. The reflected laser light passes through two imaging lenses 150 provided downstream of the rotating polygon mirror 130, and the laser light passing through the imaging lens 150 passes through the reflection mirror 160 provided downstream thereof. Is formed on the photosensitive medium.

In the conventional optical scanning device 100 as described above, the plane B of the circuit board 112 on which the laser diode 111 as a light source is mounted and one plane A of the optical frame 101 have a predetermined angle θ1. The laser light D emitted from the laser diode 111 and incident on the rotating polygon mirror 130 is formed at a predetermined angle θ2 with respect to the central axis C of the rotating polygon mirror 130. Inclined and incident.

If the θ1 and θ2 are 0 °, that is, when the laser light L is incident in parallel on the central axis of the rotating polygon mirror 130, the reflection angle increases, and the reflection surface length of the rotating polygon mirror 130 is increased. Should be designed to be longer than when θ1 and θ2 are not 0 °. In addition, as the reflection angle of the rotating polygon mirror 230 becomes larger, the difference in the amount of light between the image center and the surroundings becomes larger. Therefore, θ1 and θ2 should be given a predetermined angle, and in most optical scanning devices, 0 ° <θ2 <90 ° and designed so that θ1 = θ2.

In the color image forming apparatus, four optical scanning devices and photosensitive media are used for each color. Therefore, the cost of the optical scanning device in the image forming apparatus becomes high, and also takes up a lot of space. Therefore, in recent years, a tandem optical scanning device which simultaneously forms a plurality of light sources and a plurality of photosensitive media by using a single rotating facet mirror has been widely used. However, when using a plane of symmetry of a single rotating multi-faceted mirror 130 at the same time, in order to θ 1 (= θ 2)> 0 °, each circuit board should be provided for each light source. Therefore, a problem arises that the configuration becomes complicated and the circuit components cannot be shared.

 The present invention has been made in view of the above, an object of the present invention is to provide a photo-premise that can be made simple in configuration and miniaturized by using parts.

According to an aspect of the present invention, there is provided a light source unit including a light source unit mounted on a driving circuit board, a rotating multifaceted mirror for deflecting and reflecting laser light from the light source, and an optical frame accommodating these optical components. . The angle θ1 formed between one plane of the optical frame and the circuit board and the angle θ2 at which the laser light emitted from the light source is incident on the rotating polygonal mirror are different from each other.

Further, it is preferable that θ1 = 0 ° and θ2> 0 °.

The apparatus may further include a laser holder screwed to the circuit board to support the light source, wherein the laser holder supports the light source so that the angle formed by the light source is not perpendicular to the circuit board.

In addition, the light source may be at least two laser diodes, and the at least two laser diodes may be symmetrically installed on the same circuit board.

In addition, the light source may be two laser diodes, and each laser light emitted from the two laser diodes may be reflected and deflected in the symmetrical direction with respect to the rotation center of the rotating polygon mirror with the rotating polygon mirror.

Hereinafter, an optical apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 and 4, the optical scanning device 200 includes a light source unit 210, a cylindrical lens 220, a rotating polygon mirror 230, a driving motor 240, an imaging lens 250, and a reflection mirror ( 270 and an optical frame 201 on which the optical components are supported.

The light source unit 210 includes a circuit board 212 having a laser diode 211 as a light source, an IC (not shown) for driving the laser diode 211, and a laser holder 214 for supporting the laser diode 211. Have The laser diode 211 may have two or more light emitting points. The circuit board 212 is coupled to the laser holder 214 by a screw 213. On the other hand, both the support portions 214a and 214b having female tabs formed therein to be fastened to the screw 213 so that the angle between the laser diode 211 and the circuit board 212 is not perpendicular to each other. The length of the laser diode 211 is different.

As such, the laser diode 211 and the circuit board 212 are designed such that they are not perpendicular to each other, such that the laser light emitted from the laser diode 211 is incident on the rotating polygon mirror 230 at a predetermined angle. That is, as shown in FIG. 3, the light H emitted from one plane G and the laser diode 211 parallel to the central axis of the rotating polygon mirror 230 and the Y axis is incident on the rotating polygon mirror 230. It can be seen that the angle θ2 formed by) is greater than a predetermined angle, that is, 0 °. By making θ2 larger than 0 °, the size of the reflecting surface of the rotating polygon mirror 230 is not increased, which in turn prevents the size of the rotating polygon mirror 230 from increasing.

On the other hand, the angle θ1 formed between one plane E on the X axis of the optical frame 201 and the plane F of the circuit board 212 on which the laser diode 211 is installed is preferably 0 °. Thus, by setting θ1 to 0 °, a plurality of laser diodes 211 can be provided on one circuit board 212 (see Fig. 5).

The collimating lens 216 makes the laser light emitted from the laser diode 211 into parallel light, and is fixed inside the lens barrel 217. The lens barrel 217 is formed with an optical diaphragm 218 for imaging the laser light to a desired size. The lens barrel 217 is positioned so that the collimating lens 216 exits a predetermined position with the laser light as substantially parallel light and mounted to the laser holder 214 by an adhesive.

The cylindrical lens 220 makes parallel light into linear light in the horizontal direction. The rotating polygon mirror 230 deflects the linear light in the horizontal direction at a constant speed within an angle range of a predetermined size. The imaging lens 250 is a so-called F-theta lens and has a constant refractive index with respect to the optical axis, and refracts light of constant velocity reflected by the rotating polygon mirror 230 in the main scanning direction and corrects aberration, thereby scanning surface. Focus on the photosensitive media. The reflection mirror 270 reflects the laser light through the imaging lens 250 in a predetermined direction and enters the surface of the photosensitive medium (not shown) which is an imaging surface.

5 shows a configuration of a light scanning apparatus applied to a tandem image forming apparatus, which is an embodiment of the present invention. As shown, two optical frames 201 and 201 'are installed side by side, and each optical frame 201 and 201' is equipped with two light source units 210B and 210C (210M and 210Y) and one rotating face. Diameters 230 and 230 ′, one drive motor 240 and 240 ′ are installed. The light source units 210B, 210C, 210M, and 210Y are provided for each color (black, cyan, magenta, yellow), cylindrical lenses 220B, 220C, 220M, 220Y, and imaging lenses 250B, 250C, 250M, 250Y) and reflective mirrors 270B, 270C, 270M, and 270Y are also provided for each color. Since the two optical frames 201 and 201 'have the same structure, only one optical frame 201 will be described.

As shown, two laser diodes 211B and 211C are mounted on the same circuit board 212. In addition, the two laser diodes 211B and 211C may be arranged to be symmetrical with each other so that the laser light emitted from the two laser diodes 211B and 211C may be incident at the same angle to the rotating polygon mirror 230. The laser diodes 211B and 211C may have two or more light emitting points, respectively. A driver IC (not shown) of the laser diodes 211B and 211C is installed in the circuit board 212. In this case, the IC uses a driver IC capable of simultaneously driving a plurality of laser diodes. It is also possible.

In the conventional tandem optical scanning device, a plurality of circuit boards corresponding to a plurality of laser diodes is required, but according to an embodiment of the present invention, a plurality of laser diodes and a circuit for driving the same are provided in one circuit board. Thus, not only the number of circuit boards is reduced, but also the number of parts is reduced. Therefore, the optical scanning device can be downsized and the image forming apparatus can be downsized.

Hereinafter, the operation of the tandem optical scanning device according to the embodiment of the present invention will be described.

Each of the laser lights L1 and L2 emitted from the two laser diodes 211B and 211C is incident to the respective cylindrical lenses 220B and 220C and passes through the cylindrical lenses 220B and 220C. L2) is changed into linear light in the horizontal direction, and then enters the rotating polygon mirror 230. Each of the laser lights L1 and L2 is deflected by the rotating polygon mirror 230 in a symmetrical direction in a different direction, that is, with respect to the rotation center of the rotating polygon mirror 230. The laser lights L1 and L2 deflected by the rotating polygon mirror 230 pass through the imaging lenses 250B and 250C, respectively, and are reflected by the reflecting mirrors 270B and 270C, respectively. By imaging on the surface, an electrostatic latent image is formed on the surface of the photosensitive medium.

As such, the components of the optical scanning device may be symmetrically disposed with respect to the main scanning surface based on the rotating multifaceted mirror 230, and the rotating multifaceted mirror 230 and the driving motor 240 driving the same may be shared. In addition, by increasing the incident angles of the laser lights L1 and L2 incident on the rotating polygon mirror 230, the size of the rotating polygon mirror 230 can be prevented from increasing.

Meanwhile, in the present embodiment, an example in which two laser diodes are installed on one substrate is illustrated and described, but the present invention is not limited thereto, and four laser diodes may be installed on one substrate.

As described above, according to the optical photonic device according to the present invention, a plurality of laser beams are deflected at the same time to one rotating polygon mirror to reduce the rotation polygon mirror and the number of driving motors driving the same. The circuit components can be shared by installing a light source. Therefore, the degree of freedom in optical design is increased, the number of parts is minimized, the manufacturing cost is reduced, and the optical scanning device can be miniaturized.

In addition, it is possible to prevent the size of the rotating polygon mirror from increasing by giving a predetermined angle to the laser light incident on the rotating polygon mirror.

In addition, the relative deformation between a plurality of light sources fixed by the same circuit board and the optical frame at the time of temperature change is small, thereby preventing deterioration of the imaging performance.

Although preferred embodiments of the present invention have been shown and described, the present invention is not limited to the above-described embodiments, and the present invention is not limited to the above-described claims, and the general knowledge in the field to which the present invention pertains without departing from the gist of the present invention. Of course, anyone with a variety of modifications can be made, of course, such modifications are within the scope of the present invention.

Claims (5)

A light source apparatus comprising a light source unit mounted on a circuit board, a rotating polygon mirror for deflecting and reflecting laser light from the light source, and an optical frame accommodating these optical components, And an angle (θ1) formed between one plane of the optical frame and the circuit board and an angle (θ2) at which the laser light emitted from the light source is incident on the rotating polygon mirror. The method of claim 1, The θ1 = 0 °, and the optical scanning device, characterized in that θ2> 0 °. The method of claim 1, And a laser holder screwed to the circuit board to support the light source. And the laser holder supports the light source so that the angle formed by the circuit board is not perpendicular to each other. The method of claim 3, wherein And the light source is at least two laser diodes, and the at least two laser diodes are symmetrically installed on the same circuit board. The method of claim 4, wherein And the light source is two laser diodes, and each laser light emitted from the two laser diodes is reflected by the rotating polygon mirror in a direction symmetrical with respect to the rotation center of the rotating polygon mirror.

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