JPH06222298A - Optical scanning device - Google Patents

Abstract

PURPOSE:To miniaturize structure and prevent the optical path slippage on a light receiving surface. CONSTITUTION:In an optical scanning device for polarizing the optical beam from a light source 4 by a polariscope 20, emitting the optical beam for synchronous detection polarized by the polariscope 20 to a light receiving part 29, and setting the scanning start position to a medium to be scanned, the optical fiber 29 as the light receiving part is fitted to the fitting hole 30 of a housing 1, and the notch of a fixture 33 to be engagingly locked by the housing 1 is bited into the coat of the optical fiber 29, whereby the optical fiber 29 is fixed. The device also has a mirror 23 in which a first reflecting surface 23 for reflecting the optical beam from the light source 4 to the polariscope 20 and a second reflecting surface 23b for reflecting the optical beam from the polariscope 20 to the light receiving part 29 for synchronous detection are integrally formed. To correct the optical path slippage, a converging lens or a correcting lens 27 is further provided on the optical path for synchronous detection, or the mirror 23 having a curvature in main scanning direction or sub-scanning direction is used.

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 in laser printers, digital copying machines, facsimiles and the like.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Laid-Open No. 1-164913,
As described in Japanese Utility Model Publication No. 2-1719,
When scanning a scanning target medium with a rotating deflector of a light beam emitted from a light source, a light beam for synchronization detection deflected by the deflector outside the scanning region is made incident on a light receiving unit and detected by this light receiving unit. There is an optical scanning device in which a scanning start position with respect to a medium to be scanned is determined by controlling a clock based on a signal.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The optical scanning device described in Japanese Patent Publication No. 3 takes out the light beam after passing through the imaging lens for imaging the light beam deflected by the deflector on the medium to be scanned for synchronization detection. The length in the main scanning direction becomes long. Further, it is necessary to arrange an optical system for synchronization detection outside the imaging lens. Moreover, since the optical fiber for receiving the light beam for synchronization detection is held by the block-shaped supporting member, there is a problem that the device becomes large.

The optical scanning device described in Japanese Utility Model Laid-Open Publication No. 2-1719 has a structure in which the light beam before being incident on the imaging lens from the deflector is taken out for synchronous detection, and therefore there is an advantage in miniaturization. is there. However, due to the decentering of the polygon mirror as a deflector, if the reflecting points on each reflecting surface of the deflector are displaced or the surfaces are tilted, the detection of the light beam for synchronization detection is performed. However, there is a problem that the image quality is deteriorated.

[0005]

The invention according to claim 1 is
A light source and a deflector for deflecting a light beam emitted from the light source toward a medium to be scanned are provided in a housing, and an optical fiber for receiving a synchronous detection light beam deflected by the deflector is fitted into the housing. A dowel is formed in the housing, and a stopper having a notch that bites from both sides and a locking piece that is elastically locked to a part of the housing is provided on the outer periphery of the coating of the optical fiber.

According to a second aspect of the present invention, in the first aspect of the present invention, a condenser lens having a curvature in the sub-scanning direction and facing the light receiving surface of the optical fiber is provided, and the condenser lens is elastic. The locking piece to be locked is formed integrally with the stopper.

According to a third aspect of the present invention, a deflector for deflecting the light beam from the light source toward the medium to be scanned is provided, and the first reflecting surface for reflecting the light beam from the light source toward the deflector. And a second reflecting surface that integrally reflects the light beam for synchronization detection deflected by the deflector toward the light receiving portion.

According to a fourth aspect of the invention, in the third aspect of the invention, the first reflecting surface having a curvature in the sub-scanning direction is used.

According to a fifth aspect of the present invention, a deflector for deflecting the light beam from the light source toward the medium to be scanned is provided, and the light beam for synchronization detection deflected by the deflector is reflected toward the light receiving portion. And a correction lens that corrects the image height of the light beam on the light receiving surface according to the deflection angle is provided in the optical path between the mirror and the light receiving unit.

According to a sixth aspect of the invention, in the third aspect of the invention, the second reflecting surface having a curvature in the main scanning direction is used.

[0011]

According to the first aspect of the present invention, the optical fiber on which the light beam for synchronization detection is incident is fitted in the fitting hole of the housing, and both sides of the notch of the stopper bite into both sides of the coating of the optical fiber. However, by elastically locking the locking piece to the housing, the optical fiber can be easily fixed in a small space.

According to the second aspect of the invention, the deviation of the optical path due to the surface tilt of the deflector or the environmental change can be corrected by the condenser lens having a curvature in the main scanning direction. Also,
The stopper allows the condenser lens to be easily fixed together with the optical fiber.

According to the third aspect of the present invention, since the beam from the light source to the deflector and the beam from the deflector to the light receiving portion can be reflected by one mirror, the deflector can be used. The incident angle and the deflection angle to the light receiving section can be made close to each other. This makes it possible to reduce the size of the deflector and improve the scanning efficiency.

According to the fourth aspect of the invention, even if the deflector is tilted, the irradiation position of the light beam on the medium to be scanned and the light receiving portion for synchronization detection can be made constant by the first reflecting surface. It will be possible. This makes it possible to improve the image quality.

According to the fifth aspect of the present invention, even if the reflecting position of each reflecting surface varies due to the eccentricity of the deflector, the irradiation position of the light beam in the light receiving portion for synchronization detection is made constant by the correction lens. Is possible. This allows
The scanning start position on the medium to be scanned can be fixed and the image quality can be improved.

According to the sixth aspect of the invention, the irradiation position of the light beam on the light receiving portion can be made constant by the second reflecting surface having a curvature in the main scanning direction. As a result, the scanning start position on the medium to be scanned can be fixed and the image quality can be improved.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention described in claim 1 will be described with reference to FIGS. In FIG. 1, 1 is a housing and 2 is a light source part. The light source unit 2 faces a substrate 3 on which a drive circuit is formed, a holding member 5 for holding a semiconductor laser 4 as a light source connected to the substrate 3, and a through hole 6 formed on a side surface of the housing 1. The holding member 8 holds the collimator lens 7. The holding member 5 is fixed to the holding member 8, and the holding member 8 is fixed to the side surface of the housing 1 with the screw 9.

On both sides of the housing 1, a projection 10 projecting forward and a projection 11 projecting upward are formed, and the cover 12 for closing a part of the upper surface of the housing 1 is provided with the projections 10 and 11. The engaging notches 13 and 14 are formed, and the bent piece 15 is formed at the trailing edge. Further, a plurality of mounting holes 16 are formed in the housing 1, and a plate-shaped base body 18 mounted in the mounting holes 16 by mounting screws 17 is provided. A motor housing 19 is fixed to the base body 18.
A polygon mirror 20 as a deflector is directly connected to a motor (not shown) built in the polygon mirror 20.
A plurality of reflecting surfaces 21 are formed on the outer periphery of the. In addition,
The bent piece 15 of the cover 12 is pressed by the front edge of the base body 18.

Further, the housing 1 holds an fθ lens 22 as an imaging lens for focusing the light beam deflected by the polygon mirror 20 on a medium to be scanned (not shown) such as a photoconductor. In addition, on one side of the housing 1, a protrusion 24 that supports both sides of the mirror 23, and a mirror 23
Support 2 that supports the center of the leaf spring 25 that presses against the protrusion 24
6, a holding portion 28 that holds both sides of the correction lens 27,
A fitting hole 30 for fitting the end portion of the optical fiber 29 as a light receiving portion, and a recess 32 located above the wall surface 31 in which the fitting hole 30 is formed are formed. Mirror 23
A first reflection surface 23a that reflects the light beam from the semiconductor laser 4 toward the polygon mirror 20, and a second reflection surface that reflects the synchronization detection light beam deflected from the polygon mirror 20 toward the optical fiber 29. And a surface 23b.

The optical fiber 29 is fixed to the housing 1 by a stopper 33. That is, as shown in FIG. 2, the stopper 33 is formed of an elastic metal plate,
Locking pieces 34, 3 that are determined to have a width dimension that fits into the recess 32 of the housing 1 and hold the wall surface 31 of the housing 1
5 and a notch 36 located between the locking pieces 34.
The width d of the cutout 36 is determined to be smaller than the outer diameter D of the coating of the optical fiber 29, and thus the optical fiber 29 is fixed to the housing 1 by cutting the coating on both side edges of the cutout 36.

In such a structure, the semiconductor laser 4
The light beam emitted from is collimated by the collimator lens 7 and reflected by the first reflecting surface 23a of the mirror 23 toward the reflecting surface 21 of the polygon mirror 20. The light beam deflected by the polygon mirror 20 is scanned on the medium to be scanned by the fθ lens 22. Further, the light beam for synchronization detection deflected from the polygon mirror 20 outside the scanning region is reflected by the second reflecting surface 23b, passes through the correction lens 27, and is incident on the light receiving surface of the optical fiber 29. The light beam conducted by the optical fiber 29 is incident on a control substrate (not shown), where the semiconductor laser 4
Is set in synchronization with the clock, and the scanning start position on the medium to be scanned is controlled.

As described above, the optical fiber 29 on which the light beam for synchronization detection is incident is fitted into the fitting hole 30 of the housing 1, and the optical fiber 29 is provided on both sides of the notch 36 of the stopper 33.
It is possible to easily fix the optical fiber 29 in a small space by elastically locking the locking pieces 34 and 35 to the housing 1 while biting into both sides of the coating.

Next, an embodiment of the invention described in claim 2 will be described with reference to FIG. The same parts as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted (the same applies hereinafter). A condenser lens 37 having a curvature in the sub-scanning direction and facing the light receiving surface of the optical fiber 29 is provided. At the center of the condenser lens 37, a projection 37a that is fitted into the fitting hole 30 and faces the light receiving surface of the optical fiber 29 is integrally formed. Stopper 3
In No. 3, the interval between the locking pieces 34 and 35 is set to be slightly wider than that in the above-mentioned embodiment. Therefore, the condenser lens 37
Is pressed against the wall surface 31 of the housing 1 by a locking piece 35.

In such a structure, the deviation of the optical path due to the surface tilt of the reflecting surface 21 of the polygon mirror 20 and the environmental change can be corrected by the condenser lens 37 having a curvature in the main scanning direction. Further, the stopper 33 enables the condenser lens 37 to be easily fixed together with the optical fiber 29. Further, since the projection 37a formed at the center of the condenser lens 37 and the optical fiber 29 are fitted into the fitting hole 30, the centers of both can be accurately aligned.

Further, an embodiment of the invention described in claim 3 will be described with reference to FIGS. 1 and 4. According to the third aspect of the present invention, as described in the above embodiment, the first reflection surface 23a for reflecting the light beam from the semiconductor laser 4 toward the polygon mirror 20 and the synchronous detection deflected by the polygon mirror 20. 2 integrally formed with a second reflecting surface 23b for reflecting a light beam for light toward the optical fiber 29
3 is provided.

In such a structure, as shown in FIG. 4, the polygon mirror 2 for the light beam from the semiconductor laser 4 is used.
Since the return to 0 and the return of the light beam from the polygon mirror 20 to the optical fiber 29 can be performed by one mirror 23, the incident angle θ ₀ to the polygon mirror 20 and the deflection angle to the optical fiber 29. It is possible to make them close to θ _S. As a result, the polygon mirror 20 can be downsized and the scanning efficiency can be improved. θ is a deflection angle with respect to the medium to be scanned.

Here, as an embodiment of the invention described in claim 4, the first reflecting surface 23a in FIG. 4 is provided with a curvature in the sub-scanning direction, so that each reflecting surface 21 of the polygon mirror 20 is tilted. Even in this case, the irradiation position of the light beam on the medium to be scanned and the optical fiber 29 can be made constant by the first reflecting surface 23a.

Further, an embodiment of the invention described in claim 5 will be described with reference to FIGS. 1 and 5. In this embodiment, the image height h of the light beam on the light receiving surface of the optical fiber 29 is set to the deflection angle θ.
The correction lens 27 that corrects according to the above is provided in the optical path between the second reflecting surface 23b of the mirror 23 and the optical fiber 29.

Therefore, even if the reflection position of each reflection surface 21 varies by Δx due to the eccentricity of the polygon mirror 20, the irradiation position of the light beam on the optical fiber 29 can be made constant by the correction lens 27. . As a result, the scanning start position on the medium to be scanned can be fixed and the image quality can be improved.

Further, FIG. 6 shows an embodiment of the invention described in claim 6. In the present embodiment, the second reflecting surface 23b has a curvature in the main scanning direction so that the image height h of the light beam on the light receiving surface of the optical fiber 29 is corrected according to the deflection angle θ.

Therefore, the second reflecting surface 23b having a curvature in the main scanning direction makes it possible to make the irradiation position of the light beam on the optical fiber 29 constant. As a result, the scanning start position on the medium to be scanned is fixed,
The image quality can be improved.

Further, another embodiment of the present invention will be described with reference to FIGS. 7 and 8. As shown in FIG. 7, the first and second reflecting surfaces 23a and 23b have a curvature in the sub-scanning direction.
7, (a) is a plan view of the mirror, (b) is a cross-sectional view taken along the line AA in FIG. 7 (a), and (c) is a cross-sectional view taken along the line BB in FIG. 7 (a). Is.

Next, FIG. 8A shows an optical path from the first reflecting surface 23a to the light receiving surface 29a of the optical fiber 29. Since the first reflecting surface 23a and the second reflecting surface 23b have the function of a cylinder lens, they are shown in the shape of a lens in FIG. 8A for the sake of explanation. Second reflecting surface 23b and optical fiber 29
A cylinder lens 38 is provided between the light receiving surface 29a and the light receiving surface 29a. Further, as shown in FIG. 8B, an fθ lens 22 and a correction lens 40 are provided in the optical path from the reflecting surface 21 of the polygon mirror 20 to the scanned medium 39.

In such a structure, in FIG. 8A, the light beam from the semiconductor laser 4 has the first reflecting surface 2
The reflecting surface 2 of the polygon mirror 20 is folded back by 3a.
The light beam for synchronization detection, which is focused on 1 and is reflected by the reflecting surface 21, has its luminous flux restored by the second reflecting surface 23b, and is focused on the light receiving surface 29a of the optical fiber 29 by the cylinder lens 38. Here, the reflecting surface 21 of the polygon mirror 20 and the light receiving surface 29a are set in an optically conjugate relationship, and the surface tilt of the reflecting surface 21 is corrected.

In FIG. 8B, the light beam deflected by the reflecting surface 21 of the polygon mirror 20 is focused on the medium 39 to be scanned. Is defined as an optical conjugate relationship, the surface tilt of the reflecting surface 21 is corrected.

[0036]

According to the first aspect of the present invention, a light source and a deflector for deflecting a light beam emitted from the light source toward a medium to be scanned are provided in a housing for synchronous detection deflected by the deflector. A housing is formed with a fitting hole into which an optical fiber that receives a light beam is fitted, and a notch that bites into the outer periphery of the coating of the optical fiber from both sides and a locking piece that is elastically locked to a part of the housing. Since I have a stopper that I have,
The optical fiber on which the light beam for synchronization detection is incident is fitted into the fitting hole of the housing, and the locking piece is elastically engaged with the housing while engaging both sides of the notch of the stopper with both sides of the coating of the optical fiber. By stopping it, the optical fiber can be easily fixed in a small space.

According to a second aspect of the invention, in the first aspect of the invention, a condenser lens having a curvature in the sub-scanning direction and facing the light receiving surface of the optical fiber is provided, and the condenser lens is elastic. Since the locking piece to be locked is formed integrally with the stopper, the deviation of the optical path due to the surface tilt of the deflector and the environmental change can be corrected by the condenser lens having the curvature in the main scanning direction. Further, the condenser can easily fix the condenser lens together with the optical fiber.

According to a third aspect of the present invention, a deflector for deflecting the light beam from the light source toward the medium to be scanned is provided, and the first reflecting surface for reflecting the light beam from the light source toward the deflector. And a second reflecting surface for integrally reflecting the light beam for synchronization detection deflected by the deflector toward the light receiving portion are provided, so that the deflector for the beam from the light source is provided. Since it is possible to turn back the beam and return the beam from the deflector to the light receiving section with one mirror, the incident angle to the deflector and the deflection angle to the light receiving section can be made close to each other. This makes it possible to reduce the size of the deflector and improve the scanning efficiency.

According to a fourth aspect of the invention, in the third aspect of the invention, since the first reflecting surface having a curvature in the sub-scanning direction is used, even if a plane tilt occurs in the deflector, the medium to be scanned is scanned. Also, the irradiation position of the light beam on the light receiving portion for synchronization detection can be made constant by the first reflecting surface, and thus the image quality can be improved.

According to a fifth aspect of the invention, a deflector for deflecting the light beam from the light source toward the medium to be scanned is provided, and the light beam for synchronization detection deflected by the deflector is reflected toward the light receiving portion. Since a mirror is provided and a correction lens that corrects the image height of the light beam on the light-receiving surface according to the deflection angle is provided in the optical path between the mirror and the light-receiving unit, the reflection position of each reflecting surface due to the eccentricity of the deflector. Even if there is a variation in the position, the irradiation position of the light beam in the light receiving part for synchronization detection can be made constant by the correction lens, which allows the scanning start position on the medium to be scanned to be fixed and the image quality to be improved. Can be made.

According to the invention of claim 6, in the invention of claim 3, since the second reflecting surface having a curvature in the main scanning direction is used, the irradiation position of the light beam on the light receiving portion by the second reflecting surface. Can be made constant, whereby the scanning start position on the medium to be scanned can be fixed and the image quality can be improved.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the invention described in claim 1. FIG.

FIG. 2 is a perspective view showing a support structure for an optical fiber.

FIG. 3 shows an embodiment of the invention described in claim 2,
(A) is an exploded perspective view showing a support structure of an optical fiber and a condenser lens, and (b) is a vertical sectional side view.

FIG. 4 shows an embodiment of the invention according to claim 3,
It is explanatory drawing which shows the reflection effect of a mirror.

FIG. 5 is an explanatory diagram of an optical path showing an embodiment of the invention described in claim 5;

FIG. 6 is an explanatory diagram of an optical path showing an embodiment of the invention described in claim 6;

7A and 7B show another embodiment of the present invention, in which FIG. 7A is a plan view of a mirror, FIG. 7B is a sectional view taken along the line AA in FIG. 7A, and FIG. It is sectional drawing of the BB line part in (a).

8A is an explanatory view of an optical path from a first reflecting surface to a light receiving surface for synchronization detection, and FIG. 8B is an explanatory view of an optical path from a polygon mirror to a scanned medium.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 4 Light source 20 Deflector 21 Reflecting surface 23 Mirror 23a First reflecting surface 23b Second reflecting surface 27 Correction lens 29 Light receiving part 30 Fitting hole 33 Stoppers 34, 35 Locking piece 36 Notch 37 Condensing lens 39 Scanned medium

Claims (6)

[Claims] 1. An optical fiber for providing a light source and a deflector for deflecting a light beam emitted from the light source toward a medium to be scanned in a housing, and receiving a light beam for synchronization detection deflected by the deflector. A stopper having a notch that is formed on the outer periphery of the coating of the optical fiber from both sides and a locking piece that is elastically locked to a part of the housing. An optical scanning device characterized by being provided. 2. A condenser lens having a curvature in the sub-scanning direction and facing a light receiving surface of an optical fiber is provided, and a locking piece for elastically locking the condenser lens is integrally formed with a stopper. The optical scanning device according to claim 1, wherein 3. A deflector for deflecting a light beam from a light source toward a medium to be scanned is provided, and a first reflecting surface for reflecting the light beam from the light source toward the deflector, and the deflector. An optical scanning device comprising: a mirror integrally formed with a second reflecting surface for reflecting a deflected light beam for synchronization detection toward a light receiving portion. 4. The optical scanning device according to claim 3, wherein a first reflecting surface having a curvature in the sub-scanning direction is used. 5. A deflector for deflecting a light beam from a light source toward a medium to be scanned is provided, and a mirror for reflecting a light beam for synchronization detection deflected by the deflector toward a light receiving portion is provided, and the light is received. An optical scanning device, wherein a correction lens for correcting the image height of a light beam on a surface according to a deflection angle is provided in an optical path between the mirror and the light receiving section. 6. The optical scanning device according to claim 3, wherein a second reflecting surface having a curvature in the main scanning direction is used.