JPH11174361A - Deflecting scanning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deflecting scanning device which is made to prevent external dust entering its polygon mirror part by completely removing the space between a scanning lens and an optical box in the periphery of a polygon mirror, or the space with a lid member sealing the optical box, etc. SOLUTION: The deflecting scanning device scans a photoreceptor drum by deflecting the laser beam, emitted by a semiconductor laser unit, by the polygon mirror mounted on a motor drive part and imaging the light with a scanning lens 50, and the scanning lens 50 is formed of a resin material, a guide groove part 50a is formed in the entire circumference of the outer peripheral surface of the scanning lens 50 except its lens effective part, and a lens cap 51 having elasticity is mounted on the guide groove part 50a to compose the integrated scanning lens with the lens cap of the scanning lens 50 and lens cap 51.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection scanning device used for a laser beam printer, a laser facsimile or the like.

[0002]

2. Description of the Related Art Conventionally, this kind of deflection scanning apparatus is, for example, shown in FIG.
Is configured as shown in the plan view of FIG. An optical box 1 made of synthetic resin has a semiconductor laser output device 2 for emitting laser light, a cylindrical lens 3 for condensing the laser light linearly, and a polygon mirror 4 for deflecting and scanning the emitted laser light. A drive motor 5 for rotating the polygon mirror 4 at high speed, a scanning lens 6 formed of a resin material for forming an image of the deflected laser light,
A photosensitive drum 7 for forming an image of a laser beam, a synchronous lens 8, and a synchronous sensor 9 are provided. Further, a portion for positioning the scanning lens 6 is integrally provided in the optical box, 1a is a positioning pin for positioning the scanning lens 6 in the left-right direction, and 1b is for positioning the scanning lens 6 in the front-rear direction. It is a positioning wall and a lid member 1 is shown in the drawing.
0 extends to the lower surface. Reference numeral 1c denotes a lens installation surface for positioning the scanning lens 6 in the height direction. Although not shown, several seats lower than the lens installation surface 1c by about 0.1 mm are provided on the lower surface of the scanning lens 6, and an adhesive is applied to fix the scanning lens 6 by bonding.

FIG. 6 is a main sectional view of FIG. 5, and reference numeral 11 denotes urethane foam for preventing dust from entering from outside between the optical box 1 and the lid member 10. In the above-described configuration, the laser light emitted from the semiconductor laser output device 2 provided in the optical box 1 is condensed on a line on the surface of the polygon mirror 4 by the cylindrical lens 3, and the polygon mirror 4 is driven at high speed by the drive motor 5. , The laser beam is deflected and forms an image on the photosensitive drum 7 via the scanning lens 6. A part of the laser light deflected by the polygon mirror 4 is input to the synchronous sensor 9 via the synchronous lens 8, and becomes a write start signal.

[0004]

However, in the above conventional example, when the polygon mirror is rotated at a high speed, a negative pressure is generated around the polygon mirror, so that the outside dirty air is sucked in and the dust mixed therein. Adhered to the reflecting surface of the polygon mirror and lowered the reflectivity, resulting in a defect of an image defect. As a countermeasure, in order to improve the degree of sealing around the polygon mirror, the clearance between the scanning lens, the optical box, and the grounding portion of the lid member is reduced as much as possible. However, in reality, for example, the location of the positioning wall 1b shown in FIG. 5 between the scanning lens and the optical box needs to have a punching taper for forming the resin of the optical box. And a gap is generated on the upper surface of about 0.1 to 0.2 mm. Also, a gap of about 0.5 mm occurs between the lower surface of the scanning lens 6 and the optical box. As a result, as shown in FIG. 7, dust entered the polygon mirror portion from the outside. In particular, in recent years, the rotation of the polygon mirror tends to become faster due to the necessity of a high-definition image and a high-speed output printer.

Accordingly, the present invention solves the above-mentioned problems in the conventional example, and completely removes a gap between a scanning lens around a polygon mirror and an optical box or a lid member for sealing the inside of the optical box. It is an object of the present invention to provide a deflection scanning device that prevents external dust from entering a polygon mirror portion.

[0006]

According to the present invention, in order to solve the above-mentioned problems, a deflection scanning device is constituted as follows. That is, the deflection scanning device of the present invention is a deflection scanning device that deflects laser light emitted from a semiconductor laser unit by a polygon mirror attached to a motor drive unit, forms an image with a scanning lens, and scans a photosensitive drum. The scanning lens is formed of a resin material, a guide groove is provided on the entire outer peripheral surface of the scanning lens other than the lens effective portion, and a lens cap having an elastic force is attached to the guide groove, and the scanning lens and the scanning lens are mounted. It is characterized in that a scanning lens with a lens cap is formed integrally with the lens cap. Further, the deflection scanning device according to the present invention is characterized in that the lens cap is formed of a frame-shaped lens cap having a substantially rectangular outer shape, and is mounted in a guide groove of a square scanning lens. Further, the deflection scanning device of the present invention is characterized in that the lens cap is formed of a lens cap having a circular cross section, and is mounted in a guide groove of a trapezoidal or V-shaped scanning lens. Further, in the deflection scanning device according to the present invention, in the scanning lens with the lens cap, the entire periphery of the outer periphery of the lens cap is elastically contacted with an optical box or a lid member for sealing the inside of the optical box. It is characterized by having.

[0007]

According to the present invention, as described above, a scanning lens is formed of a resin material, a guide groove is provided on the entire outer peripheral surface of the scanning lens other than the lens effective portion, and an elastic force is applied to the guide groove. By attaching a lens cap having a scanning lens and the lens cap to form a scanning lens with a lens cap integrated with the lens cap, the scanning lens with the lens cap is fixed to an optical box, for example, a lid When the inside of the optical box is sealed with a member, the outer peripheral surface of the lens cap is elastically grounded to the optical box or the lid member, so that the gap at the peripheral portion of the scanning lens can be completely removed, and the external It is possible to completely prevent intrusion of dust.

[0008]

Embodiments of the present invention will be described below. Embodiment 1 FIGS. 1 to 3 show a deflection scanning apparatus according to Embodiment 1 of the present invention. Since the entire configuration is the same as that of the conventional example, a detailed description is omitted below. 1 is a top view of the deflection scanning device, FIG. 2 is a main sectional view thereof, and FIG. 3 is a perspective view of a lens cap. In FIG. 1, reference numeral 50 denotes a scanning lens formed of a resin material, reference numeral 50a denotes a rectangular guide groove portion provided so as to be connected to the entire periphery of the lens, and reference numeral 51 denotes a frame-shaped lens having an elastic force and an outer shape of a substantially rectangular shape. Cap.

In the above configuration, the lens cap 51 is elastically spread and mounted in the guide groove of the scanning lens 50, and the integrated scanning lens with the lens cap is set at a predetermined position of the optical box 1; An adhesive is applied to the adhesive seating surface 1d provided on the box 1 and is adhesively fixed. With such a configuration, when the inside of the optical box is sealed with the lid member 10, the outer peripheral surface of the lens cap can be elastically contacted between the surface of the optical box and the surface of the lid member. Therefore, the gap can be completely removed from the periphery of the scanning lens, and the intrusion of dust from the outside can be completely prevented.

In the lens cap of the present invention, a material or a shape is selected so that the repulsive force against compression is extremely small as compared with the force for fixing the lens (adhesive force of the adhesive in this embodiment). Therefore, the lens and the optical box are not displaced in the assembled state.

[Embodiment 2] FIG. 4 shows a deflection scanning apparatus according to Embodiment 2 of the present invention. Since the entire configuration is the same as that of Embodiment 1, detailed description will be omitted. In the figure, 52 is a scanning lens, 52a is a trapezoidal guide groove,
It may be V-shaped. Reference numeral 53 denotes a rubber band having a circular cross section and elastic force, and has a connected shape as in the first embodiment. Compared to the first embodiment, the contact area with the optical box and the lid member is small, but the manufacture is simple and the cost can be reduced.

[0012]

As described above, according to the present invention, a scanning lens is formed of a resin material, and a guide groove is provided on the entire outer peripheral surface of the scanning lens other than the lens effective portion, and an elastic force is applied to the guide groove. A scanning lens with a lens cap is integrated with the scanning lens and the lens cap, and a scanning lens and an optical box around the polygon mirror are provided by the scanning lens with the lens cap. Alternatively, it is possible to completely remove a gap with a lid member or the like that seals the inside of the optical box, thereby preventing external dust from entering the polygon mirror portion, and realizing a deflection scanning device without image deterioration. be able to. Further, according to the present invention, the mounting of the lens cap is simple, and conventionally, urethane foam is provided on the upper surface and the lower surface of the scanning lens, but such troublesome work is unnecessary and the assembling can be easily performed. . Further, according to the present invention, it is not necessary to strictly control the dimensional accuracy of the optical box in order to reduce the gap between the scanning lens and the optical box as in the related art, and the dimensional accuracy can be reduced by mounting the lens cap, Can be manufactured easily and can be configured at low cost.

[Brief description of the drawings]

FIG. 1 is a top view according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view according to the first embodiment of the present invention.

FIG. 3 is a perspective view according to the first embodiment of the present invention.

FIG. 4 is a sectional view according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a conventional example.

FIG. 6 is a diagram showing a conventional example.

FIG. 7 is a diagram showing a conventional example.

[Explanation of symbols]

 1: optical box 1d: seating surface for bonding 10: lid member 50, 52: scanning lens 50a, 52a: guide groove 51: lens cap

Claims (4)

[Claims] 1. A deflection scanning device for deflecting a laser beam emitted from a semiconductor laser unit by a polygon mirror mounted on a motor drive unit, forming an image with a scanning lens, and scanning a photosensitive drum, wherein the scanning lens is made of resin. Made of a material, a guide groove is provided on the entire outer peripheral surface of the scanning lens other than the lens effective portion, and a lens cap having an elastic force is attached to the guide groove,
A deflection scanning device, wherein a scanning lens with a lens cap is integrated with the scanning lens and the lens cap. 2. The deflection scanning device according to claim 1, wherein the lens cap is formed by a frame-shaped lens cap having a substantially rectangular outer shape, and is mounted in a guide groove of a rectangular scanning lens. . 3. The deflection scanning apparatus according to claim 1, wherein the lens cap is formed of a lens cap having a circular cross section, and is mounted in a guide groove of a trapezoidal or V-shaped scanning lens. 4. The scanning lens with a lens cap, wherein the entire outer periphery of the lens cap is elastically contacted with an optical box or a lid member for sealing the inside of the optical box. Any one of claims 1 to 3
13. The deflection scanning device according to item 9.