JP2005301179A - Multibeam optical recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multibeam optical recorder attaining high speed optical recording by realizing scanning lines very close to each other at high light utility efficiency in an optical system in which an optical recording is performed by scanning with multibeams from a semiconductor laser array. <P>SOLUTION: A second multibeam generation means further increases the number of beams from the multibeams emitted from the semiconductor laser array, so that optical scanning lines very close to each other are obtained on an optical recording face. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laser printer that scans and prints multiple beams emitted from a plurality of semiconductor lasers, that is, multi-beams.

In a laser printer using a multi-beam, the number of multi-beams, the rotational speed of the rotary polygon mirror, and the light modulation speed can be reduced, so that a laser printer that prints at high speed can be realized.
FIG. 2 shows a schematic diagram in which a multi-beam emitted from a semiconductor laser array formed in an array by integrating laser light emitting portions on a semiconductor substrate is applied to a laser printer apparatus.

  In FIG. 2, each of the multi-beams emitted from the semiconductor laser array 1 is collimated by the collimator lens 2, the beam width is expanded by the lenses 3 and 4 which are beam expanders, and the rotating polygon mirror 6 is used on the photosensitive drum 8. Scanning. The cylindrical lens 5 is for correcting a scanning line pitch error on the photosensitive drum due to the tilting of the reflecting surface of the rotary polygon mirror 6. The scanning lens 7 narrows the beam scanned by the rotary polygon mirror onto the photosensitive drum 8.

  In this optical system, the light spot array on the photosensitive drum surface by the semiconductor laser array is configured such that the array arrangement direction is perpendicular to the scanning direction.

  The interval between the semiconductor laser light emitting portions constituting the semiconductor laser array is usually about 100 μm, and a small one is 14 μm. On the other hand, the semiconductor laser light emitting section has a light spot size of about 3 μm in the array arrangement direction. Accordingly, the interval between the semiconductor laser array light emitting portions is about 4 to 30 times larger than the size of the light spot at the light emitting portion. For this reason, when there is no slit 12, the beam interval of the multi-beams narrowed down on the photosensitive drum is larger than the spot diameter at the same magnification, as shown at 14 in FIG. 3, and the scanning lines formed by the multi-beams are adjacent to each other. It will not be closely related to.

  If printing is performed in this state, a non-exposed area is generated between the scanning lines, and printing with good image quality cannot be expected. The slit 12 blocks the beam in the sub-scanning direction, and spreads it by diffraction so that the size of the light spot 15 is approximately p on the photosensitive drum surface, thereby bringing adjacent scanning lines into close contact.

  4 and 5 are for explaining the operation of the optical system of FIG. 2 in the sub-scanning direction and the scanning direction. Only one central beam from the semiconductor laser array is shown. 6 shows the position of the rotating polygon mirror. The slit 12 enlarges the beam diameter on the surface of the photosensitive drum 8 by blocking the beam emitted from the collimator 2 in the sub-scanning direction.

  By the way, in this method, since the light spot diameter to be narrowed is increased from 4 times to 30 times as compared with the case where there is no slit by blocking the beam with the slit, there is a disadvantage that the light use efficiency becomes very small.

  Therefore, this method has a problem that the light intensity on the photosensitive drum is reduced and high-speed optical recording cannot be achieved.

  Accordingly, an object of the present invention is to provide an apparatus capable of realizing high-speed optical recording by realizing close scanning lines with high light utilization efficiency in an optical system for scanning and optically recording multiple beams from a semiconductor laser array.

  In order to solve the above problems, in the present invention, a semiconductor laser array in which a plurality of semiconductor laser light emitting units are integrated is used as the first multi-beam generating unit, and the first multi-beam generating unit emits the first multi-beam generating unit. And a second multi-beam generating means for generating a second multi-beam from the multi-beam, and arranging the array direction of the second multi-beam perpendicular to the scanning direction for optical recording. . By adopting the above method, optical scanning lines close to each other can be obtained without reducing the light utilization efficiency, and high-speed and high-precision optical recording becomes possible.

  Since the optical recording apparatus using the semiconductor laser array of the present invention can form close scanning lines with high light utilization efficiency, an apparatus capable of high-speed optical recording can be realized.

  First, the principle of the present invention will be described with reference to FIG. FIG. 6 shows a light spot array formed by multi-beams from the semiconductor laser array on the surface of the photosensitive drum as in FIG.

  In FIG. 3, the size of the light spot is increased to p by the operation of the slit 12. In FIG. 6 of the present invention, the multi-beam from the semiconductor laser array is a beam 16 that is multiplied by the second multi-beam generating means. FIG. 6 shows a case where the number is doubled for simplicity. In this case, in order to realize the close scanning line 17, the slit may be adjusted so that the light spot spreads to p / 2 in the sub scanning direction.

  Therefore, compared with the case of FIG. 3, in the case of FIG. 6, the fall of the light utilization efficiency by a slit can be suppressed small. In the description of FIG. 6, the second multi-beam generating means has shown a case where the number of multi-beams is increased by a factor of two. be able to. Ultimately, the slit can be eliminated by setting the number of beams appropriately.

  As the second multi-beam generating means, a polarizing element or a diffraction grating can be used.

  An optical system used in the optical recording apparatus of the present invention is shown in FIG. In the figure, reference numeral 13 denotes a diffraction grating as second multi-beam generating means, which multiplies the number of beams from the semiconductor laser array 1 by a plurality. The operation of other optical components has already been described with reference to FIG. The slit 12 is for forming a close scanning line.

  Although FIG. 1 shows an example in which the slit 12 is used, it is not necessary to use the slit 12 when a close scanning line can be formed with only a plurality of beams generated by the second multi-beam generating means.

  FIG. 7 shows a diffraction grating 20 that can be used as the second multi-beam generating means. This diffraction grating has a function of generating a plurality of diffracted lights 22 having substantially the same light intensity from the incident beam 21. In the figure, five beams consisting of -2nd order, -1st order, 0th order, + 1st order, and + 2nd order diffracted light are generated.

  FIG. 8 shows an example of a polarizing element that can be used as the second multi-beam generating means. When laser light is incident on this polarizing element, the quarter-wave plate 23 makes the laser light circularly polarized, and is branched into two laser lights by the subsequent Wollaston prism 24.

1 shows a multi-beam optical recording apparatus of the present invention. 1 shows a conventional multi-beam optical recording apparatus. It is operation | movement explanatory drawing of the optical system of the conventional multi-beam optical recording apparatus. It is operation | movement explanatory drawing of the optical system in the subscanning direction of the conventional multibeam optical recording device. It is operation | movement explanatory drawing of the optical system in the scanning direction of the conventional multi-beam optical recording apparatus. It is operation | movement explanatory drawing of the optical system of the multi-beam optical recording apparatus of this invention. It is operation | movement explanatory drawing of the diffraction grating used as a 2nd multi-beam generation means by this invention. It is operation | movement explanatory drawing of the polarizing element used as a 2nd multi-beam generation means by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor laser array 2 Collimator lens 3 Lens 4 Beam expander 5 Cylindrical lens 6 Rotating polygon mirror 7 Scan lens 8 Photosensitive drum 11 Photo detector 12 Slit 13 Diffraction grating

Claims (4)

  A semiconductor laser array in which a plurality of semiconductor laser light emitting sections are integrated is used as the first multi-beam generating means, and a second multi-beam is generated from the first multi-beam emitted from the first multi-beam generating means. A multi-beam optical recording apparatus having a second multi-beam generating means, optically recording an array arrangement direction of the second multi-beams perpendicular to a scanning direction.   A multi-beam optical recording apparatus using a polarizing element as the second multi-beam generating means according to claim 1.   A multi-beam optical recording apparatus using a diffraction grating as the second multi-beam generating means according to claim 1. A semiconductor laser array in which a plurality of semiconductor laser light emitting sections are integrated is used as the first multi-beam generating means, and a second multi-beam is generated from the first multi-beam emitted from the first multi-beam generating means. A multi-beam optical recording apparatus having a second multi-beam generating means, optically recording the array arrangement direction of the first and second multi-beams perpendicular to the scanning direction.

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