JPH05281486A - Scanning optical device - Google Patents

Abstract

PURPOSE:To easily peel image forming lenses in safety by forming through holes for peeling the image forming lenses in an optical frame and closing the through holes by arranging the image forming lenses. CONSTITUTION:The light beam emitted by a laser light source unit 20 is transmitted through a cylindrical lens 21 as the 1st image forming lens and deflected by a rotary polygon mirror 31 to scan a body to be scanned. The deflected scanning light beam irradiates a photosensitive body drum as the body to be scanned by a concave lens 22 as the 2nd image forming lens having ftheta characteristics and a convex lens 23 as the 3rd image forming lens. The through holes 11 and 12 are bored where the image forming lenses 22 and 23 are arranged, the image forming lenses 22 and 23 are fixed to the optical frame 10 by ultraviolet-ray setting adhesion, and the through holes 11 and 12 are closed, so even when the lenses are peeled after the adhesion, the image forming lenses 22 and 23 can easily be peeled off by being pressed from the reverse surface of the optical frame 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning optical device used in laser beam printers, laser facsimiles and the like.

[0002]

2. Description of the Related Art Conventionally, an optical member provided in a scanning optical device is attached to an optical frame by being urged by an elastic member such as a spring or rubber, or by an ultraviolet curing adhesive. ..

[0003]

However, these mounting methods have the following problems. 1. When urged and attached by a spring, the optical member (lens) must be positioned and fixed in three dimensions with respect to the optical frame. However, when a spring is used, the three-dimensional pressing force is applied to the spring. Since it is due to accuracy, it is likely to become unstable, and when trying to obtain a desired pushing force three-dimensionally, the spring shape becomes very complicated and the reliability at the time of positioning is lacking.

Further, if the spring shape is complicated, the processing cost becomes very high. 2. When biased and attached by rubber When the optical member (lens) is biased and attached to the optical frame by rubber, there is a problem that the lens surface is soiled by the additive contained in the rubber and the transmittance is changed.

3. When using an adhesive, the method of attaching the optical member (lens) to the optical frame with an ultraviolet-curing adhesive or the like is becoming popular because it is inexpensive, but this method has a defect in the lens. In some cases, the optical frame and its associated components must be discarded, and a lot of waste is generated.

Further, if the defective lens is forcibly peeled from the optical frame, it is very dangerous if the lens breaks.

[0007]

Therefore, in the present invention, the optical member is fixed to the optical frame with an adhesive,
In addition, by disposing this optical member in a scanning optical device that can be easily separated from the optical frame, it is possible to minimize waste.

[0008]

Embodiments of the present invention will be described with reference to the drawings. 1 and 2 are a structural view and a sectional view of a scanning optical device of the present invention.

In FIG. 1, reference numeral 20 denotes a semiconductor laser that emits a light beam, a collimator lens that makes the emitted light beam a substantially parallel light, and a laser drive circuit that modulates the light beam emitted by image information. It is a laser light source unit.

A light beam emitted from the laser light source unit 20 passes through a cylindrical lens 21 which is a first imaging lens, and is deflected and scanned by a rotary polygon mirror 31 for scanning the light beam on a scan object. To be done.

Here, the rotary polygon mirror 31 has a plurality of reflecting mirror surfaces, and the plurality of reflecting mirror surfaces are processed so that the reflectances are substantially the same. Further, when the light beam is deflected, the reflection angle of the light beam differs, but it is processed so that almost the same reflectance can be obtained at any reflection angle. Reference numeral 30 is a drive motor that drives the rotary polygon mirror 31 to rotate in the arrow direction with high accuracy.

The deflected and scanned light beam is applied to the photosensitive drum, which is the object to be scanned, by the concave lens 22 that is the second imaging lens having the fθ characteristic and the convex lens 23 that is the third imaging lens.

The laser light source unit 20, the lens groups 21, 22, 23, the rotary polygon mirror 31 and the like are arranged in the optical frame 10 which is processed with high precision so as to be accurately arranged at desired positions. Has been done.

In this scanning optical device, if the reflecting mirror surface of the rotary polygon mirror 31 becomes dirty and the reflectance varies, the light amount of the light beam applied to the photosensitive drum also varies, so that the recorded image also has uneven density. It will be. This phenomenon becomes more remarkable as the rotating polygon mirror rotates at a higher speed, because the reflecting mirror surface of the light beam becomes dirty as the rotating polygon mirror entrains dust in the periphery.

Therefore, in the embodiment of the scanning optical apparatus of the present invention, a cover 40 for covering the optical frame 10 is provided as shown in FIG. 2, and dust is prevented from entering near the rotary polygon mirror 31. Collar 4 with a shield effect
1 and 42 are provided.

Next, a method of fixing the imaging lenses 22 and 23 to the optical frame 10 will be described.

In the optical frame 10, the imaging lens 2
Through holes 11 and 12 are formed where 2 and 23 are provided. Then, the imaging lenses 22 and 23 are fixed to the optical frame 10 with an ultraviolet curing adhesive.
Here, the through holes are completely closed by disposing the imaging lenses 22 and 23 in the optical frame 10.

By blocking the through hole with the imaging lens, the shield effect of the rotary polygon mirror is not impaired as described above.

The through hole is used as follows.

First, when the imaging lens is fixed to the optical frame with an adhesive such as an ultraviolet curing adhesive,
It becomes necessary to confirm the adhesive strength. In such a case, the optical frame 10 using the through holes 11 and 12
You can check the adhesive strength by pressing from the backside with a tension gauge or the like without worrying about chipping of the imaging lens.

Further, even when the imaging lens is to be peeled off after being adhered from the optical frame due to a defective processing of the imaging lens or the like, it is very easy to remove the imaging lens by pushing it from the back surface of the optical frame, and in addition, Even if the imaging lens is broken, fragments are not scattered and the risk is considerably reduced, so that the imaging lens and the optical frame can be easily regenerated, and it is not necessary to generate extra waste.

Further, when performing such an adhesive strength test or peeling, it is preferable that the force applied to the imaging lens is dispersed because it is more difficult to break. Further, although two through holes are provided in each lens in this embodiment, the number and position of the through holes are not particularly limited.

As described above, the hole for peeling the image forming lens is provided in the optical frame in advance, and the image forming lens is provided so as to close the hole for peeling, thereby rotating due to dust. It is possible to prevent the polygon mirror from becoming dirty.

An image forming lens mounting portion showing another embodiment of the scanning optical device of the present invention will be described below. In the figure,
The same members as those in FIGS. 1 and 2 having the same functions are designated by the same reference numerals and the description thereof will be omitted.

The view shown in FIG. 3 is a view showing the vicinity of a land portion for fixing the imaging lens 23 to the optical frame 10 by adhesion. Reference numeral 11 is the above-described through hole, and 13 is an adhesive land portion to which an image forming lens 23 is attached by applying an adhesive.

In the above-described embodiment, the land 13 is formed at the upper part of the through hole 11, and the through hole 11 is covered by disposing the imaging lens 23. When there is a problem such as flowing into the hole, it is better to slightly lower the peripheral portion 14 of the through hole 11. According to the experiment, if the gap between the land portion 13 and the peripheral portion 14 is several tens μm to several hundreds μm, the same shielding effect against dust as in the above-described embodiment can be obtained. In this way, by providing the step between the bonding land and the peripheral portion of the through hole, it is possible to prevent the adhesive from flowing into the through hole when the imaging lens 23 is bonded and fixed to the optical frame 10.

FIG. 4 is a sectional view showing the shape of the peripheral portion 15 of the through hole 11 and the vicinity of the bonding land portion 13. The peripheral portion 15 of the through hole 11 has a concave shape so that excess adhesive 50 can be easily collected, and by completely blocking the through hole 11 with the adhesive 50, dust does not enter the optical frame 10. Is configured as follows.

In FIG. 5, the imaging lens 22 is attached to the optical frame 10.
It is the figure which showed the land part vicinity adhere | attached and fixed to. Land portions 16 for applying an adhesive are provided over the entire circumference of the through hole 12. An adhesive is applied to the 16 lands to fix the imaging lens 22 to the optical frame, so that the adhesive completely closes the gap between the through hole and the imaging lens so that external dust is not inside. Is configured.
Reference numeral 17 in this figure denotes an adhesion relief portion that is one step lower than the adhesion land portion 16.

In the embodiment shown in FIG. 6, the through hole 11 is provided in the mounting reference surface 18 of the imaging lens 23. The adhesive 50 is applied to the land portion 51 different from the mounting reference surface 18.
The effect of shielding against dust from the outside is also improved by applying it on the above and attaching the imaging lens 23.

It should be noted that the present invention does not relate to the shape of the through hole and the peripheral portion thereof, but a through hole for pressing the imaging lens adhered and fixed to the optical frame is provided in the optical frame, and this hole is The same effect can be obtained as long as it can be closed by attaching the imaging lens.

[0031]

As described above, the optical frame is provided with the through hole for peeling the imaging lens, and the through hole is provided to block the through hole. ． Check the adhesive strength of the imaging lens 2. The imaging lens can be peeled off easily and safely.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a scanning optical device showing a first embodiment of the present invention.

2 is a cross-sectional view of the scanning optical device of FIG.

FIG. 3 is a sectional view of an imaging lens mounting portion and another embodiment of the present invention.

FIG. 4 is a cross-sectional view of an imaging lens mounting portion showing another embodiment of the present invention.

FIG. 5 is a diagram illustrating an imaging lens attachment portion showing another embodiment of the present invention.

FIG. 6 is a sectional view of an imaging lens mounting portion showing another embodiment of the present invention.

[Explanation of reference numerals] 10 optical frame 11 through hole of optical frame 12 through hole of optical frame 13 adhesive land portion of optical frame 16 adhesive land portion of optical frame 22 imaging lens 23 imaging lens

Claims (2)

[Claims] 1. A means for generating a light beam, a means for deflecting and scanning the light beam on an object to be scanned, and an optical member for condensing the deflected light beam on the object to be scanned.
There is a through hole at a position where the optical member is arranged in the optical frame in a scanning optical device configured by an optical frame that arranges these means at a desired position,
The scanning optical device is characterized in that the through hole is closed by disposing the optical member. 2. The scanning optical device according to claim 1, wherein the optical member is attached to the optical frame with an adhesive.