KR940004754Y1 - Hologram laser scanning unit - Google Patents

Abstract

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Description

Optics of the hologram laser scanning unit

1 (a) and 1 (b) of FIG. 1 are plan and side views showing the internal structure of the optical device of the HLSU according to the prior art.

2 (a) and 2 (b) of FIG. 2 correspond to FIG. 1 (a) and FIG. 1 (b) of the HLSU optical device according to the present invention.

3 (a) and 3 (b) of FIG. 3 are side cross-sectional views of a perspective view showing a first mounting portion of the present invention device.

Figure 4 is a perspective view showing a second mounting portion of the present device.

5 (a), 5 (b) and 5 (c) of FIG. 5 are perspective views showing the assembling method of the optical device of the HLSU according to the present invention.

* Explanation of symbols for main parts of the drawings

1: LD 2: Collimator

3: pre-scan hologram 4: scan hologram disk

5: motor 6: lower plate reflector

7: top reflector 8: the first adjustment mirror

10: second adjustment mirror 11: recording hologram

14 detection mirror 15 photodiode

18: first mounting part 19: second mounting part

The present invention relates to an optical device of a hologram laser scanning unit (HLSU) using a laser beam. In particular, two upper and lower reflectors generate a scanning light beam pattern to reduce the manufacturing error of the device and reduce the assembly process. HLSU's optics are designed to simplify and reduce the size of the device.

A conventional apparatus having such a function is a 780nm LD (Laser Diode, 1), which is a light source, as shown in FIG. 1 (a), and a collimator (2) for collimating light from the LD (1). Pre-Scan Hologram (3) that first diffracts the collimated light, Scan Hologram Disk (1) which scans the first diffracted light from the hologram (3) ), The motor 5 for rotating the disk 4, the first and second reflecting mirrors 6, 7 for guiding light from the disk 4 to the curved mirror 8, the scanning angle of the scanning line ( curved mirror 8 for parallelizing θ), third reflecting mirror 9 for guiding a beam reflected from the curved mirror 8 to the recording hologram 10, and a constant spot on the photosensitive drum 11 It was composed of a recording hologram 10 for spraying a beam to a spot size and a toner support 12 for receiving toner powder.

FIG. 1 (a) is a plan view of FIG. 1 (b), wherein the photodiode 14 detects the arrival time of the laser beam to the photosensitive drum 11 and the detection mirror for inducing the beam to the photodiode 14 ( 13) is shown.

The conventional apparatus having the above configuration is diffracted in the pre-scan hologram 3 of the laser beam passing through the collimator 2 in the LD 1 as shown in FIG. 1, and then rotated by the motor 5. The optical system of the HLSU is spread from the scanning hologram 4 to the curved mirror 8 and from the curved mirror 9 to the recording hologram 10 by the scanning hologram disk 4. Since a certain distance is required, three reflective mirrors 6, 7, 9 are used to form an optical pattern to reduce the size of the device. In addition, in order to determine the start of scan (SOS) time, a portion of the scanning line is reflected by the detection mirror 13 so that the photodiode 14 can detect it.

The conventional apparatus having the above-described configuration and operation uses three reflective mirrors 6,7, and 9 to construct an optical pattern that can minimize the size of the apparatus. The three reflective mirrors 6,7 9) and the optical component, that is, the curved mirror 8, the recording hologram 10, and the photodiode 14 have a problem in that a complicated structure must be manufactured with high precision independently to position a specific position and angle. .

In addition, in order to mass-produce complex structures, it is necessary to mold by molds. The higher the precision, the higher the manufacturing cost and the post-processing process.In addition, the relative error of the mounting parts of the engineering parts must be inspected when the product is assembled. When fixing the optical pattern using an arbitrary inspection equipment, there was a problem in that it is difficult to set the reference point of the jig for the inspection equipment.

Therefore, the present invention is to provide an optical device of HLSU that can solve the problems of the conventional optical device of the HLSU as described above.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

Referring to FIG. 2 (a) and FIG. 2 (b) of FIG. 2, the present invention is a light source LD (1), a collimator (2) for collimating light from the LD (1), and this collie A pre-scan hologram (3) for first diffracting the mated light, a scan hologram disc (4) for scanning the first diffracted beam, a motor (5) for rotating the scan hologram disc (4), and The lower plate reflector 6 and the upper plate reflector 7 reflecting the scanning beams from the scanning hologram disk 4 several times, and the degree of reflection of the scanning lines is adjusted to the curved mirror 9 at a certain beam path length. The first adjusting mirror 8 to be incident, the curved mirror 9 to parallel the scanned beams, and the scanning line reflected from the curved mirror 9 are fixed in parallel to the lower and upper plate reflectors 6 and 7. A recording in which a scanning beam is sprayed on the recording hologram 11 at an arbitrary angle and the second adjustment mirror 10 and the photosensitive drum 12 have a predetermined spot size. Program (11) also consists of a toner base (12) that bathyeo toner powder.

FIG. 3 is a perspective view showing a first mounting portion 18 for fixing the first adjustment mirror 8 and the photodiode 15. The mounting portion 18, as shown in the cross-sectional view of FIG. Both ends of the adjustment mirror (8) can be fixed with two leaf springs (16), and two adjustment holes (17) can be installed above and below the center of the mirror (8) to finely rotate the mirror (8). Have a configuration to ensure that. 4 is a perspective view showing the second mounting portion 19 on which the curved mirror 9 and the detection mirror 14 are mounted.

The device of the present invention having the configuration as described above is assembled by the method as shown in FIG. That is, as shown in FIG. 5 (a) of FIG. 5, the first mounting portion 18 and the fourth mounting portion are disposed on the lower plate reflector 6, which has a hole 22 made so that the motor 5 is not caught and a hole 21 into which the scanning line is incident. After placing the second mounting portion 19 to which the curved mirror 9 and the detection mirror 14 are attached as shown in the drawing, the recording hologram 11 is slit for scanning the line passing through the scanning line as shown in FIG. Attach the top reflector (7) attached on (20) to the first and second mounting portions (18, 19). After inspecting the parallelism of the upper and lower reflectors 6 and 7 of the module assembled as shown in FIG. 5 (c) of FIG. 5, LD (1), collimator (2) and pre-scan hologram (3) This module is installed on the structure where the scan hologram disk 4 and the motor 5 are fixed. The scanning beam reflected by the adjusting mirror 17 of the first mounting unit 18 by the detection mirror 14 of the second mounting unit 19 is adjusted until the photodiode 15 is detected in an arbitrary shape, thereby correcting light. Create a pattern.

In the operation of the device of the present invention having the above configuration, as shown in FIG. 2, light from the LD 1 is diffracted in the pre-scan hologram 3 through the collimator 2. The primary diffraction beams produced here are scanned by the scan hologram disk 4 into the curved mirror 9 at any scan angle. At this time, as shown in FIG. 5, two large images are bonded to the lower and upper surfaces of the first mounting portion 18 and the second mounting portion 19 so as to have the scan width required by the laser beam printer (LBP) and aligned in parallel. The lower reflector 7 and 6 reflect the scanning beam several times.

In addition, the first adjustment mirror 8 is adjusted to have an accurate optical path, and the adjustment is made by using the intensity of light detected by the photodiode 15.

The optical device of HLSU according to the present invention having the configuration and operation method as described above has two flatness between the upper and lower plate reflectors with good flatness instead of the method of installing the reflector and various optical components in a precise and complicated structure in the conventional apparatus. By using the optical pattern generation module bonded with the genuine mounting portion, it is possible to obtain high precision compared to the conventional mold, and thus the accuracy of assembly can be inspected using the photodiode attached to the first mounting portion. The assembly process offers simple advantages over conventional devices. In addition, since the scanning beam is reflected several times between the two upper and lower plate reflectors, the size of the device can be reduced.

Claims (3)

LD (1) which is a light source, a collimator (2) for collimating the light from the LD (1), a pre-scan hologram (3) for diffracting the collimated light in the first order, and the first diffracted beam A scan hologram disk 4 for scanning the scan hologram disk 4, a motor for connecting the scan hologram disk 4, and a lower plate reflector 6 for reflecting the scanning beams from the scan hologram disk 4 several times; A first adjustment mirror 8 which adjusts the degree of reflection of the scanning lines by the upper plate reflector 7 and the upper and lower reflector 6 and 7 so as to enter the curved mirror 9 at a predetermined scanning line path distance; The curved mirror 9 for parallelizing the beams and the scanning line reflected by the curved mirror 9 are incident on the recording hologram 11 fixed in parallel to the upper and lower reflectors 6 and 7 at an arbitrary angle. A second adjusting mirror 10 provided between the lower plate reflector 6 and 7 and the second adjusting mirror 10; And a recording hologram (11) for spraying the scanning line from the drum (12) onto the drum (12) at a predetermined spot size. The detection mirror (14) according to claim 1, wherein the detection mirror (14) reflects part of the scanning line from the upper and lower plate reflectors (6) and (7) to the photodiode (15), and the reflection by the detection mirror (14). An optical device of a hologram laser scanning unit, comprising a photodiode (15) for detecting scan lines and providing scan start information or pattern inspection information. The parallel spaced bezel of the upper and lower reflector (6) (7) according to claim 1 or 2, comprising first and second mounting portions (18) and (19) at both ends thereof, wherein the first mounting portion (18). Is fixed with a spring and is adjustable as a control sphere 17 is installed as a first adjustment mirror 8, the photodiode 15 and the second mounting portion 19 is the curved mirror 9, Optical device of the hologram laser unit, characterized in that the detection mirror (14) is installed.