JPH04234721A - Scanning optical device - Google Patents

Abstract

PURPOSE:To shorten the time for a stage for adhering a synthetic resin lens and to enhance reliability. CONSTITUTION:A cylindrical introducing hole 17a is provided from the front surface toward rear surface 17c of the synthetic resin lens 1 7 near the right and left ends which are off the effective range of this lens. A UV curing adhesive is interposed between the inner side on the base of an optical box 11 and the rear surface 17c and is irradiated with UV rays from light below the resin through an introducing hole 17a to fix the lens 17. The UV rays pass the inside of the synthetic resin from the base 17b of the introducing hole 17a to the rear surface 17c but since the distance is short, the UV rays irradiate the adhesive with substantially no attenuation, thereby curing the resin.

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, for example, in a laser beam printer.

0002

2. Description of the Related Art FIG. 5 is a plan view of a scanning optical system of an information recording device, and FIG. 6 is a cross-sectional view thereof. A polygon mirror 5 is disposed inside, and a spherical lens 6, a toric lens 7, and a reflecting mirror 8 are sequentially disposed in the output direction.

The laser beam emitted from the laser oscillator 2 passes through a collimator lens 3 and a cylindrical lens 4, is deflected by a polygon mirror 5, and becomes a scanning beam corrected by fθ by a spherical lens 6 and a toric lens 7.
The light is reflected by a reflecting mirror 8 and directed toward a photosensitive drum (not shown).

In this conventional scanning optical device, glass lenses are used for the spherical lens 6 and the toric lens 7, and an ultraviolet curing adhesive is used to fix the glass lenses, and ultraviolet rays are irradiated through the lenses. This accelerates the curing of the adhesive.

In recent years, lenses made of synthetic resin have been increasingly used in order to improve lens productivity, reduce weight, reduce cost, and improve performance by making lenses aspheric. As the synthetic resin material, polycarbonate resin is preferred because it has good optical properties, little dimensional change due to moisture absorption, and excellent strength.

[0006]

[Problems to be Solved by the Invention] However, polycarbonate resin has a low UV transmittance compared to glass, about a fraction of the transmittance, so it is necessary to use UV-curable adhesive like conventional glass lenses. If an attempt is made to fix the material with an agent, the following problems will occur. That is, the ultraviolet irradiation time becomes longer, resulting in lower workability, and uncured portions of the adhesive occur due to uneven irradiation. However, if the intensity of ultraviolet rays is made too strong, the polycarbonate resin may deteriorate due to a photooxidation reaction.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a scanning optical device which eliminates the above-mentioned drawbacks, allows bonding of synthetic resin lenses in a short time, and is highly reliable.

[0008]

[Means for Solving the Problems] In order to achieve the above-mentioned object, a scanning optical device according to the present invention is a scanning optical device using a synthetic resin lens in an optical system, in which the mounting of the synthetic resin lens is This is characterized in that an introduction hole for a light beam for accelerating adhesive curing is formed in the part.

[0009]

[Operation] In the scanning optical device having the above-described structure, when a lens is attached, a curing accelerating light beam is incident through the introduction hole to accelerate curing of the lens fixing adhesive.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail based on the embodiments shown in FIGS. 1 to 4. Note that the same reference numerals as in the conventional example indicate the same members.

FIG. 1 shows a plan view of a scanning optical system of an information recording device, in which a collimator lens 3 and a cylindrical lens 4 are sequentially arranged on the optical axis of a laser oscillator 2, which is attached to the side wall of an optical box 11 facing inward. The polygon mirror 5 is located on the extension thereof. In the reflection direction of the polygon mirror 5, a spherical lens 6 and a toric lens 1 are sequentially arranged.
7. A reflective mirror 8 is installed.

The toric lens 17 is made of polycarbonate resin, and has a cylindrical light introduction hole 17a extending from the upper surface to near the lower surface outside the effective range at the left and right ends. As shown in FIG. 2, the bottom of the light introduction hole 17a is connected to the concave lens surface 1.
7b is formed and directly faces the mounting flat part 17c which is a part of the bottom surface of the toric lens 17.

To attach the toric lens 17 to the optical box 11, drop a small amount of ultraviolet curable adhesive onto the specified position of the optical box 11, that is, the mounting position of the toric lens 17, and place the mounting flat part 17c on top of it. The toric lens 17 is left still, and ultraviolet rays are irradiated directly below from the light introduction hole 17a. Then, the ultraviolet light beam is expanded by the concave lens surface 17b and irradiates the mounting flat part 17c, thereby promoting curing.

FIG. 3 is a side view of the inside of the optical box 21 of the second embodiment, in which a toric lens 27 made of polycarbonate resin is formed into a cylindrical shape parallel to the optical axis from the rear surface toward the front outside the left and right effective range. A light introduction hole 27a is formed, the bottom of which is a concave lens surface 27b. Then, a flat mounting portion 27c is formed on the back side of the light introduction hole 27a, that is, near the left and right ends of the front surface of the toric lens 27.
It is bonded to the rear surface of the fixing portion 21a protruding from the bottom surface of the optical box 21.

In this embodiment, the toric lens 27 is in contact with the mounting flat part 27c via the ultraviolet curing adhesive applied to the fixing part 21a, and the light introduction hole 27a is in contact with the toric lens 27.
It is fixed by horizontally injecting ultraviolet rays from above.

FIG. 4 shows a cross-sectional view of the vicinity of the toric lens according to the third embodiment.
It is almost the same as the embodiment, but its bottom surface is a convex lens surface 3.
7b, so that the incident ultraviolet rays are focused on the mounting flat part 37c of the toric lens 37.

In this shape, since the ultraviolet light beam is narrowed down by the convex lens surface 37b, accurate and efficient ultraviolet irradiation is possible even if the adhesive surface with the optical box 31 is made small in area.

In all of the above embodiments, since the optical path length of ultraviolet rays in the polycarbonate resin is shortened, the curing time of the adhesive is short, and uncured portions due to uneven irradiation are less likely to occur. In the embodiment, a toric lens was described, but other synthetic resin lenses may also be used.

[0019]

Effects of the Invention As explained above, in the scanning optical device according to the present invention, the optical path length within the synthetic resin is shortened by the introduction hole of the synthetic resin lens attachment part, and a stronger curing promoting light beam is applied to the adhesive surface. Since it can be irradiated, the work time for fixing the lens during manufacturing is shortened and reliability is high.

[Brief explanation of the drawing]

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

FIG. 2 is a sectional view taken along line AA in FIG. 1;

FIG. 3 is a sectional view of a second embodiment.

FIG. 4 is a cross-sectional view of a lens of a third embodiment.

FIG. 5 is a plan view of a conventional example.

FIG. 6 is a sectional view of a conventional example.

[Explanation of symbols]

2 Laser oscillator 3 Collimator lens 4 Cylindrical lens 5 Polygon mirror 6 Spherical lens 11, 21, 31 Optical box 17, 27, 37 Toric lens 17a, 27a
, 37a Light introduction holes 17b, 27b Concave lens surfaces 17c, 27c, 37c Mounting flat part 21a Fixing part 37b Convex lens surface

Claims (2)

[Claims] 1. A scanning optical device using a synthetic resin lens in an optical system, characterized in that an introduction hole for a light beam for accelerating adhesive curing is formed in a mounting portion of the synthetic resin lens. 2. The scanning optical device according to claim 1, wherein the bottom of the introduction hole is formed into a lens shape.