JPH11249044A - Optical fiber device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber device with which laser power is hardly dispersed in plural laser beams by providing a l./4 wavelength plate at the prescribed position of an optical path between a semiconductor laser and an optical element group. SOLUTION: On the laser emission planes of semiconductor lasers 1a-1c, 1/4 wavelength plates 2a-2c are respectively provided and emitted laser beams 8a-8c are respectively converged to respective plural optical fibers 5a-5c by respective plural lenses 3a-3c and lenses 4a-4c and passed through the optical element group and irradiate a body to be irradiated such as a photosensitive body. In this case, the 1/4 wavelength plates 2a-2c are provided on the emission planes of the semiconductor lasers 1a-1c but the 1/4 wavelength plates 2a-2c can be provided between the lenses 3a-3c and the lenses 4a-4c or on the incident planes of the optical fibers 5a-5c as well. Thus, the dispersion in the transmission factors of respective laser beams 8a-8c with respect to an optical element can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device used for an electrophotographic apparatus such as a laser printer and a copying machine, and more particularly to an optical device using an optical fiber.

[0002]

2. Description of the Related Art In electrophotographic devices such as laser printers and copiers, in electrophotographic devices of high-speed printing specifications,
In general, a configuration is adopted in which a plurality of semiconductor lasers are used to record an electrostatic latent image on a photoconductor with a plurality of laser beams.

Since the light intensity of a semiconductor laser tends to fluctuate due to a change in temperature, when mounting a plurality of semiconductor lasers, the individual semiconductor lasers are arranged at a certain distance from each other.
It is preferable to take care so that the heat generated by one semiconductor laser during operation does not reach the other semiconductor lasers,
When the individual semiconductor lasers are spaced apart from each other as described above, a large mounting space is required for the individual semiconductor lasers and the optical element group for guiding the laser light emitted from the individual semiconductor lasers to an irradiation target or the like. This causes a problem that the size of the apparatus is increased.

As one means for solving this problem, an optical fiber is used to connect between the semiconductor laser and the optical element group, and a plurality of semiconductor lasers can be relatively freely mounted without substantially changing the configuration of the optical element group. Optical fiber optical devices that can be arranged have been proposed.

[0005]

By the way, in the above-mentioned optical fiber optical device, even when a plurality of semiconductor lasers are mounted so that the polarization directions are the same, the laser light is variously refracted when passing through the optical fiber. Because the light propagates, the polarization directions of the laser beams emitted from the emission surfaces of the plurality of optical fibers are not all the same but are individually different. Here, optical elements such as lenses and mirrors generally have different transmittances and reflectivities depending on the polarization direction. Therefore, when the polarization directions are different among a plurality of laser lights, the transmission of a plurality of laser lights passing through the optical element group is performed. The rates will be different for each. Furthermore, since the angle of incidence of the light scanned by the polygon mirror on the optical element after the polygon mirror differs depending on the scanning position, laser light emitted from a plurality of semiconductor lasers passes through the optical element at each scanning position. The rates will be different.

If the laser beams emitted from the plurality of semiconductor lasers pass through the optical element at each scanning position and have different transmittances, the laser power applied to an object to be irradiated such as a photoreceptor is different. When printing is performed, there arises a problem that shading unevenness occurs on a printed matter.

An object of the present invention is to provide an optical fiber optical device in which laser power of a plurality of laser beams hardly varies.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a plurality of semiconductor lasers, a plurality of optical fibers provided corresponding to the semiconductor laser, and a plurality of laser beams emitted from the optical fibers. This is achieved by having an optical element group to be handled and a quarter-wave plate provided at a predetermined optical path between the semiconductor laser and the optical element group.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a semiconductor laser 1
The laser emission surfaces of a, 1b, and 1c are provided with quarter-wave plates 2a, 2b, and 2c, respectively. A plurality of optical fibers 5 are respectively provided by the lenses 4a, 4b, 4c.
The light is condensed on a, 5b, and 5c, passes through an optical element group (not shown), and is irradiated on an irradiation target such as a photoconductor. In FIG. 1, a quarter-wave plate is provided on the emission surface of the semiconductor lasers 1a, 1b, 1c, but the quarter-wave plate is provided between the lenses 3a, 3b, 3c and the lenses 4a, 4b, 4c. May be provided or 1/4
The wave plate may be provided on the incident surface of the optical fibers 5a, 5b, 5c.

FIG. 2 shows another embodiment of the present invention. In FIG. 2, laser beams 8a, 8b, and 8c emitted from semiconductor lasers 1a, 1b, and 1c are respectively provided with lenses 3a, 3b, and 3c and a lens 4a. , 4b, 4c, the optical fibers 5a, 5b, 5
c, the light exiting surfaces of the optical fibers 5a, 5b, 5c which are arranged at the same interval on a straight line and are united into one.
The wave plate 2 is provided.

FIG. 3 also shows another embodiment of the present invention. In FIG. 3, semiconductor lasers 1a, 1b, 1c are shown.
The laser beams 8a, 8b, 8c emitted from the lens 3a,
The light emitted from the exit surface of the optical fibers 5a, 5b, 5c is condensed on the optical fibers 5a, 5b, 5c by the lenses 3b, 3c and the lenses 4a, 4b, 4c and arranged linearly at the same interval and integrated into one. The 群 wavelength plate 2 is provided in the optical element group 6 while passing through the element group 6. The optical element group 6 is configured by combining known optical elements such as a collimator lens, a spherical lens, a cylindrical lens, a polygon mirror, an Fθ lens, and a mirror according to specifications.

[0012]

As described above, according to the present invention, a quarter-wave plate is provided at a predetermined position on the optical path between a plurality of semiconductor lasers, a plurality of optical fibers, and a group of optical elements.
It is possible to provide an optical fiber optical device capable of eliminating variations in the transmittance of each laser beam with respect to an optical element.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing another embodiment of the present invention.

FIG. 3 is a schematic configuration diagram showing another embodiment of the present invention.

[Explanation of symbols]

1a, 1b, 1c ... semiconductor laser, 2, 2a, 2b, 2c ...
1/4 wavelength plate, 3a, 3b, 3c, 4a, 4b, 4c: lens, 5a, 5b, 5c: optical fiber, 6: optical element group, 8
a, 8b, 8c: laser light.

Claims (4)

[Claims] 1. A plurality of semiconductor lasers, a plurality of optical fibers provided corresponding to the semiconductor lasers, an optical element group for handling a plurality of laser beams emitted from the optical fibers, and the semiconductor laser And a quarter-wave plate provided at a predetermined position of the optical path between the optical element groups. 2. The optical fiber optical device according to claim 1, wherein said quarter-wave plate is provided between said semiconductor laser and said optical fiber. 3. The optical fiber optical device according to claim 1, wherein said quarter-wave plate is provided at an emission end of said optical fiber. 4. The optical fiber optical device according to claim 1, wherein said quarter-wave plate is provided in said optical element group.