JPH04237013A - Synthetic resin lens for laser scanning - Google Patents

Abstract

PURPOSE:To surely and rapidly adhere and fix the synthetic resin lens to a fixing base plate by applying a UV effect type adhesive thereon. CONSTITUTION:Thin mounting parts 10a to 10d are projected like tongues by 2 pieces each on both sides of the longitudinal direction of a scanning lens 10 in the lower part of the lens effective region of the thick scanning lens 10 and are formed integrally with the scanning lens 10. The unequal curing of the adhesive is averted and the adhering time is shortened if the adhesive is applied only on the rear surfaces of the mounting parts 10a to 10d and the mounting parts 10a to 10d are irradiated with UV rays after positioning at the time of fixing such scanning lens 10.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin lens for laser scanning used, for example, in a writing scanning optical system in a laser beam printer or the like.

0002

2. Description of the Related Art Conventionally, in a writing scanning optical system such as a laser beam printer, as shown in FIG.
After a light beam from a laser unit 1 consisting of a laser light source and a collimating lens is transmitted through a cylindrical lens 2, it is deflected and scanned by a rotating polycon mirror 3, and then by a scanning lens 5 fixed to a fixed base 4.
A scanning line is imaged on the photosensitive drum 6.

This scanning lens 5 has a constant speed writing function.
In order to have a condensing effect on the light beam, it is generally made into a flat shape parallel to the laser scanning plane.In recent years, glass has become popular due to its low cost and ease of processing into aspherical shapes. Instead, molded synthetic resins are often used.

The scanning lens 5, which is molded from synthetic resin, can be fixed to the fixed base 4 of the main body of the apparatus by screwing using a presser plate, which requires a simpler installation process than screwing. A fixing method using an adhesive is known, which has the advantage of reducing mechanical stress and deformation. As the adhesive, it is considered most effective to use an ultraviolet curable adhesive whose curing time can be easily controlled and which causes little mechanical strain after curing. In this case, after positioning the adhesive-coated surface 5' on the back surface of the scanning lens 5 on the fixed base 4, as shown in FIG. The adhesive is cured and bonded by irradiating ultraviolet rays V through the optical fiber F or F'.

[0005]

[Problems to be Solved by the Invention] However, in the above-mentioned conventional example, the scanning lens 5 needs to have a certain thickness in order to secure an effective area, and synthetic resin generally has a high light absorption rate for ultraviolet rays. Therefore, when the scanning lens 5 is irradiated with ultraviolet rays from above, the energy of the ultraviolet rays required for curing the adhesive, that is, the ultraviolet ray irradiation time, and the electric capacity of the ultraviolet light source increase. On the other hand, when ultraviolet rays are irradiated from an oblique direction of the scanning lens 5, the curing time of the adhesive at the edge of the adhesive application surface can be shortened, but the drawback is that curing becomes uneven and the reliability of the adhesive strength is low. has.

An object of the present invention is to provide a synthetic resin lens for laser scanning that can be securely and quickly adhesively fixed with an ultraviolet curable adhesive.

[0007]

[Means for Solving the Problems] A synthetic resin lens for laser scanning according to the present invention to achieve the above object is a lens adhesively fixed to a fixed base of a light beam scanning device with an ultraviolet curing adhesive. The present invention is characterized in that a thin mounting portion protruding outside the effective area of the lens is provided by integral molding.

[0008]

[Operation] The synthetic resin lens for laser scanning having the above-mentioned structure is manufactured by applying an ultraviolet curing adhesive to the back or front surface of the protruding mounting portion and positioning it on a fixed base.
By irradiating ultraviolet rays from a direction perpendicular to the plane of the thin-walled part, the thin-walled part can be adhesively fixed to the fixed base reliably and in a short time.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail based on the embodiments shown in FIGS. 1 to 7. Note that the same reference numerals as in FIGS. 8 and 9 indicate the same members. Furthermore, the scanning synthetic resin lens described in the following embodiments is used in the scanning optical system of the laser beam printer described with reference to FIG.

FIG. 1 is a perspective view, and FIG. 2 is a cross-sectional view. At the bottom of the effective area of the thick scanning lens 7, thin mounting portions 10a to 10d are provided on both sides of the scanning lens 10 in the longitudinal direction. Each of them has two protruding tongues.

When the scanning lens 10 is adhesively fixed to the fixed base 4, as shown in FIG.
After applying an adhesive to the adhesive-coated surfaces 10a' to 10d' on the back side and positioning it on the fixed base 4, the mounting parts 10a to 10d are irradiated with ultraviolet rays V from above using an optical fiber F.

[0012] When using an ultraviolet curing adhesive,
Generally, a mercury lamp with a wavelength of about 357 nm and a light source power of about 200 W to 1 KW is used as an ultraviolet light source, so in the conventional scanning lens 5 with a thickness of about 13 mm, the transmittance of the adhesive is less than 1%, which is about 1 The irradiation time is approximately 2 minutes. However, in the scanning lens 10 of this embodiment, when the length L1 of the protruding portion of the mounting portions 10a to 10d is approximately 5 mm, and the wall thickness L2 is approximately 2 to 3 mm, the ultraviolet irradiation transmittance is 20 to 30%. The adhesive fixation can be completed within a few seconds, and the time required for ultraviolet rays can be significantly shortened, and the UV irradiation time is evenly distributed. The thickness of the scanning lens 10 is preferably 5 mm or less.

As a method of fixing the scanning lens 10 of this embodiment, as shown in FIG. 4, a hole 4a is provided in the fixing base 4, and an adhesive coated surface 10a' is formed on the surface of the mounting portions 10a to 10d.
There is also a method of applying adhesive to ~10d' and bonding it to the fixed base 4. In this case, ultraviolet rays V are irradiated from the back surface of the scanning lens 10 with the optical fiber F, but the same method as the above-mentioned bonding method is also available. Effects can be obtained. Furthermore, there is a relative degree of freedom in the position of the optical fiber F, and it is also possible to reduce the height of the scanning lens 10.
This is particularly effective when the tolerance in the height direction of 0 is small.

FIG. 5 shows a scanning lens 11 according to a second embodiment.
, there is a thin mounting portion 11 extending horizontally and further vertically at the bottom of the scanning lens 11.
a is formed integrally with the scanning lens 11. When adhesively fixing this scanning lens 11 to the fixed base 4, as shown in FIG.
As shown in FIG. 2, a stepped portion 4b matching the shape of the mounting portion 11a is provided on the fixed base 4, and bonding is performed in the same manner using the stepped portion 4b side of the mounting portion 11a as the adhesive application surface 11a'.

By forming the mounting portion 11b in such a shape, it becomes possible to position the scanning lens 11 in the vertical direction without using an adhesive, so that the tolerance in the height direction of the scanning lens 11 can be adjusted in terms of optical design. This is particularly effective when small. The attachment portion 11a may be formed to extend in the longitudinal direction of the scanning lens 11 as described above, or it may be partially formed in the longitudinal direction if the area is larger than the area necessary to ensure secure adhesive fixation. There is no problem in forming it.

FIG. 7 shows a scanning lens 12 according to a third embodiment.
, the scanning lens 12 has two thin mounting portions 12 in the longitudinal direction in most areas outside the effective area of the lens.
a and 12b are integrally molded in a protruding manner, and a thin mounting portion 12c is similarly protruded and integrally molded in a plane perpendicular to the mounting portions 12a and 12b on one side of the scanning lens 12 other than the bottom surface. There is.

When the scanning lens 12 is adhesively fixed to the fixed base 4, a protrusion 4c that abuts the mounting portion 12c is provided on the fixed base 4, and the back surfaces of the mounting portions 12a to 12c are coated with the adhesive surface 12a'. ~12c'. By providing the mounting portion 12c not only on the bottom surface of the scanning lens 12 but also on the side surface in this manner, the reliability of positioning accuracy and adhesive strength is improved.

[0018]

Effects of the Invention As explained above, the synthetic resin lens for laser scanning according to the present invention is provided with a thin mounting part that is integrally molded and protrudes outside the effective area of the lens. After applying the ultraviolet curable adhesive and positioning it on the fixing base, by irradiating it with ultraviolet rays from a direction perpendicular to the thin plane, adhesive fixation can be completed in a short time, shortening the process and reducing costs. In addition, since the mounting part protrudes, the adhesive does not harden unevenly, ensuring high adhesion, and the distortion of the adhesive after curing is unlikely to extend to the effective light transmitting part of the lens, which has the effect of preventing optical deterioration. .

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a first embodiment.

FIG. 2 is a sectional view.

FIG. 3 is an explanatory diagram of an adhesive fixing method.

FIG. 4 is an explanatory diagram of an adhesive fixing method.

FIG. 5 is a perspective view of a second embodiment.

FIG. 6 is an explanatory diagram of an adhesive fixing method.

FIG. 7 is a perspective view of a third embodiment.

FIG. 8 is a perspective view of a conventional example.

FIG. 9 is an explanatory diagram of a conventional adhesive fixing method.

[Explanation of symbols]

4 Fixed base 4a Opening 4b Step 4c Protrusions 10, 11, 12 Scanning lenses 10a to 10d, 11a, 12a to 12c Mounting part 1
0a', 10c', 11a', 12a' to 12c'
Adhesive surface

Claims (3)

[Claims] 1. A lens adhesively fixed to a fixed base of a light beam scanning device with an ultraviolet curable adhesive, characterized in that a thin mounting portion protruding outside the effective area of the lens is provided by integral molding. A synthetic resin lens for laser scanning. 2. The synthetic resin lens for laser scanning according to claim 1, wherein the attachment portions are provided on multiple sides of the lens. 3. The synthetic resin lens for laser scanning according to claim 1, wherein the mounting portion has a thickness of 5 mm or less.