JPH03293313A - Optical scanner - Google Patents

Abstract

PURPOSE:To constitute the scanner so that a photosensitive drum is irradiated surely with an emitted light beam by providing a condensing means consisting of a photosetting resin on an emitting end of a optical waveguide array. CONSTITUTION:An optical waveguide array 15 is formed by providing many lines of optical waveguides for propagating a light beam emitted from a light source 11 to a photosensitive drum 20. An incident end 15a of this optical waveguide array 15 is formed in such a circular are shape as surrounds a polygon mirror 14, and an emitting end 15b is formed n a linear shape being parallel to the center shaft of the photosensitive drum 20. Also, the emitting end 15b is provided with a condensing lens 30 made of a photosetting resin, by which a light beam in the emitting end 15 by forms s image to one-to-one one the photosensitive drum 20. In such a way, since the condensing lens 30 consisting of photosetting resin is provided on the emitting end of the optical waveguide array 15, so that the photosensitive drum 20 is irradiated surely with the emitted light beam.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical scanning device using electrophotographic technology such as a laser printer, and more particularly to an optical scanning device using an optical waveguide array.

[Prior Art] As a prior art, an optical scanning device has been proposed that uses an optical waveguide array to scan a photosensitive drum with a light beam.

This optical waveguide array has a large number of optical waveguides arranged in an arc shape at one end to serve as an input end for a light beam, and the other end arranged in a straight line to serve as an output end for a light beam. This optical waveguide is composed of two types of materials that have different refractive indexes for the light beam from the light source.The material with a higher refractive index forms the core, which forms the center of the optical waveguide, and the material with a lower refractive index, which forms the cladding, forms the center of the optical waveguide. It was formed to surround the surrounding area.

At the output end, the light beam is emitted with an aperture angle determined by the difference in refractive index between the core and the cladding.The light beam at the output end is directed onto the photosensitive drum by a gradient index lens array such as a SELFOC lens array as a focusing means. was irradiated.

[Problems to be Solved by the Invention] However, in an optical scanning device using such an optical waveguide array, since a gradient index lens array, which is a separate member from the optical waveguide array, is used as a condensing means at the output end,
There was a problem in that it was difficult to align the output end of the optical waveguide array and the gradient index lens array. Another problem is that such a gradient index lens array is expensive.

If the output end of the optical waveguide array is placed close to the photosensitive drum without using such a gradient index lens array, the output end will be contaminated by toner on the photosensitive drum, resulting in a decrease in image quality. This caused the

The present invention has been made in order to solve the above-mentioned problems, and it is possible to align the optical waveguide array and the light collecting means by providing a light collecting means made of a photocurable resin at the output end of the optical waveguide array. The object of the present invention is to provide an inexpensive optical scanning device that does not require the following steps.

[Means for Solving the Problems] An optical scanning device of the present invention includes a light source that emits a light beam based on image information, and a large number of optical waveguides that propagate the light beam from the light source from its input end to its output end. an optical waveguide array formed by the optical waveguide array, and an optical deflector that deflects the light beam from the light source so as to sequentially enter the input end of the optical waveguide array, and a photocurable resin is provided at the output end of the optical waveguide array. The structure is equipped with a light condensing means consisting of:

[Function] In the optical scanning device of the present invention having the above configuration, the light beam emitted from the light source based on image information is sequentially incident on the input end of the optical waveguide array by the optical deflector, and then the light beam is inputted to the output end of the optical waveguide array. However, since a condenser lens made of a photocurable resin is provided at the output end of the optical waveguide array, the spread of the emitted light beam is suppressed and the photosensitive drum is reliably irradiated.

[Example] Hereinafter, an example embodying the present invention will be described with reference to the drawings.

As shown in FIG. 1, the optical scanning device 10 includes a light source 11 that emits a light beam based on image information, and an optical waveguide array formed of a large number of optical waveguides for propagating the light beam from the light source 11 to a photosensitive drum 20. 15, and a polygon mirror 14 for deflecting the light beam from the light source 11 to the input end of the optical waveguide array.

The light source 11 generates a light beam by blinking in response to an electric signal based on image information, and specifically, a semiconductor light source such as a laser diode (LD) or a light emitting diode (LED) is used.

A collimating lens 12 is provided downstream in the propagation direction of the light beam from the light source 11 to convert the light beam from the light source 11 into a parallel light beam. A condensing lens 13 for condensing the light beam from the collimating lens 12 is provided further downstream of the collimating lens 12. The polygon mirror 14 is arranged to be rotatable at high speed by a motor (not shown), and the light beams focused by the condenser lens 13 are sequentially guided to the input end of the optical waveguide array 15 by the rotation of the polygon mirror 14. ing.

The optical waveguide array 15 is formed by arranging a large number of optical waveguides for propagating the light beam emitted from the light source 11 to the photosensitive drum 20. The input end 15a of this optical waveguide array 15 is formed in an arc shape surrounding the polygon mirror 14, and the output end 15b is formed in the shape of an arc surrounding the polygon mirror 14.
It is formed in a straight line parallel to the central axis of. The output end 15b is provided with a condenser lens 30 made of photocurable resin, so that the light beam at the output end 15b is imaged one-to-one on the photosensitive drum 2o.

FIG. 2 is a plan view of the output end 15b portion of the optical waveguide array 15.

The condensing lens 30 as a condensing means is manufactured by the following steps.

A. The output end 15b of the optical waveguide array 15 is immersed in a photocurable resin material. The photocurable resin is, for example, a mixture of an acrylic acid ester polymer (typically, a refractive index at the time of curing of about 1.54), which is an ultraviolet photocurable resin, and an initiator.

B. Light from an ultraviolet light source for curing the material is made uniformly incident from the incident end 15a of the optical waveguide array 15.

C, due to the difference in refractive index between the core 21 and the cladding 22, the core 2
The light that has propagated through the core 1 is emitted at the output end 15b, and the optical power density distribution of this output light beam is approximately the sum of Gaussian distributions with the central axis of each core 21 as the apex. Therefore, since the degree to which the photocurable resin is cured follows this optical power density distribution, the shape of the cured portion becomes a chevron shape centered on the core 21, as roughly shown in FIG. For example, if the optical power of ultraviolet light at one emission end is 300 μW at a wavelength of 360 nm using the above-mentioned material, this ultraviolet light curable resin will reach the second level in about 100 m5ec.
It hardened into the chevron shape shown in the figure.

D. After curing, the output end 15b of the optical waveguide array 15 is taken out from the photocurable resin and the uncured material is washed. Then, the condenser lens 30 is formed by again irradiating the entire hardened area with light that hardens the material. The cleaning method uses ultrasonic cleaning in acetone. Furthermore, since the above-mentioned materials do not harden when they come into contact with oxygen, it is necessary to carry out the process in a nitrogen atmosphere or in a vacuum.

Through the steps described above, the condenser lens 30 is formed at the output end 15b of the optical waveguide array 15.

Next, the operation of such an optical scanning device 10 will be explained.

A light source 11 blinks and emits a light beam based on an image signal, and this light beam is guided to a polygon mirror 14 via a collimating lens 12 and a condensing lens 13. Then, by the rotation of the polygon mirror 14, the light beam from the light source 11 is guided to the input end 15a of the optical waveguide array 15, and is sequentially incident on each optical waveguide constituting the optical waveguide array 15.

The light beam incident on the optical waveguide array 15 is propagated within the core 21 by being totally reflected at the interface between the core 21 and cladding 22 of the optical waveguide due to the relationship in refractive index between them. This light beam is sequentially emitted from each optical waveguide at the output end 15b of the optical waveguide array 15, but at this time, the spread of the emitted light beam is suppressed by the condenser lens 30 having the above-described configuration, and the light beam is is reliably irradiated onto the photosensitive drum 20.

By the above-described operation, the light beam from the light source 11 that blinks depending on the image information is scanned at a constant speed in the direction of the central axis of the photosensitive drum 20, and an image is recorded.

Then, each time one line of light scanning is completed, the photosensitive tram 2o
is rotated by a drive source (not shown), and optical scanning is performed by repeating optical line scanning.

Moreover, the condensing lens 30 has a chevron-shaped shape that suppresses the spread of the emitted light beam and reliably irradiates the light beam onto the photosensitive drum 20. Since the condensing lenses 30 having the above-mentioned configuration are made by aligning with the corresponding cores 21, there is no need to align the output end 15b and the condensing lenses 30 as if they were separate members. do not have.

Furthermore, since only a small amount of photocurable material is used, it can be constructed at a very low cost.

[Effects of the Invention] As detailed above, since the optical scanning device of the present invention is equipped with a light condensing means made of a photocurable resin at the output end of the optical waveguide array, the light beam emitted from the output end is reliably focused. is irradiated onto the photosensitive drum. Further, the manufacturing method eliminates the need for alignment between the optical waveguide array and the light condensing means, and has the advantage that it can be constructed at low cost.

[Brief explanation of drawings]

FIG. 1 is a perspective view schematically showing an optical scanning device according to an embodiment of the present invention, and FIG. 2 is a plan view of the vicinity of the output end of the optical waveguide array. In the figure, 11 is a light source, 14 is an optical deflector, 15 is an optical waveguide array, 15a is an input end, 15b is an output end, and 30 is a condensing means.

Claims (1)

[Claims] 1. A light source that emits a light beam based on image information, an optical waveguide array formed by arranging a large number of optical waveguides that propagate the light beam from the light source from its input end to its output end, and light from the light source. An optical scanning device comprising an optical deflector that deflects the beam so that the beam is sequentially incident on the input end of the optical waveguide array, wherein the output end of the optical waveguide array is provided with a light condensing means made of a photocurable resin. An optical scanning device characterized by: