KR100304637B1 - Optical scanning unit for color image output device - Google Patents

Abstract

An optical scanning unit for a color image output device for scanning a plurality of scanning lines to form an electrostatic latent image corresponding to each color on an image surface of a photosensitive medium is disclosed.

The disclosed optical scanning unit includes: a light source module having a substrate and a surface light laser array disposed adjacent to each other on the substrate and emitting at least two or more lights in a stacking direction; A drive source for providing a rotational force; A hologram disk rotatably installed in the drive source, the hologram disk diffraction-transmitting each of the plurality of light incident from the light source module in different paths and deflecting the plurality of incident light; And optical path converting means for converting the traveling path of the incident light so that the plurality of light deflected and scanned from the hologram disk form a parallel scanning line on the image plane, and to secure the traveling path of the light corresponding to each color. do.

Description

Gwangju Yarn Unit for Color Image Output Device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light scanning unit for a color image output device, and more particularly, to a light scanning unit for a color image output device employing a hologram disk.

In general, a laser scanning unit (LSU) is a device for forming an electrostatic latent image (Electrostatic Latent Image) required for the development by scanning the laser light on the photosensitive medium. This optical fiber unit is widely used in an image output apparatus for forming an image by an electrophotographic method, and is classified into a rotating polyscopy method and a hologram disk method according to the type of deflector employed.

When the rotating multi-faceted optical fiber unit is employed in color image output devices such as color laser printers, digital color copiers, scanners, and color facsimiles, for example, four optical fiber units correspond to each of four colors of yellow, magenta, cyan, and black. Since the structure is complicated, assembly and alignment are difficult, and the size of the color image output device is increased.

In view of such a point, a hologram disk type optical scanning unit for a color image output device has been disclosed in the related art.

The color image output device includes photosensitive drums (30a) and (30b) in which a photowangsa unit (10) and four optical scanning lines scanned from the photosensitive yarn unit (10) are formed, and electrostatic latent images corresponding to the respective colors are formed. 30c) 30d, developing units 32a, 32b, 32c, 32d formed in each of the photosensitive drums 30a, 30b, 30c and 30d to perform development, and each photosensitive drum ( Developing the chargers 34a, 34b, 34c, 34d for charging 30a, 30b, 30c, and 30d to a predetermined potential, and the photosensitive drums 30a, 30b, 30c, 30d. And a transfer belt 36 for transferring the transferred sheet S and the transfer sheet S to which the transferred image is transferred.

The optical fiber unit 10 includes four light source assemblies 11a, 11b, 11c, and 11d corresponding to each of four colors, a hologram disk 15 rotatably installed by a driving source 13, and a light source. A plurality of planar mirrors 17a, 17b, 17c, 17d, 19a, 19b, and 19c arranged to change the path of travel of the light irradiated from the assemblies 11a, 11b, 11c, and 11d. 19d) 23a, 23b, 23c, 23d, f-θ The lens 21a, 21b, 21c, 21d, and the cylindrical lenses 25a, 25b, 25c, and 25d are comprised. Each of the light source assemblies 11a, 11b, 11c, and 11d includes a laser diode LD for irradiating laser light, a lens L for focusing the light irradiated from the laser diode LD, and the laser. It is composed of a cylindrical lens (CL) for correcting the difference in the radiation angle between the vertical direction and the horizontal direction of the light irradiated from the diode (LD) to be the parallel light of the axisymmetric. The plurality of planar mirrors 17a, 17b, 17c, 17d, 19a, 19b, 19c, 19d, 23a, 23b, 23c, and 23d are used for optical scanning lengths according to respective colors. Ensure a satisfactory light path. remind f-θ The lenses 21a, 21b, 21c and 21d and the cylindrical lenses 25a, 25b, 25c and 25d are the main scanning direction and the photosensitive drum 30a which are the scanning directions by the hologram disc 15. Aberration correction and linearity in the sub-scan direction, which is the rotation direction of (30b), 30c, and 30d, are corrected.

In this way, the conventional optical device using the conventional hologram disk configured by using a laser module (LD) corresponding to each color by using a separate module, when the incident position is irradiated from each laser diode to enter the hologram disk, Will be different. Therefore, when manufacturing the hologram disc, the hologram pattern should be different at each position. Also, f-θ By providing the lenses 21a, 21b, 21c, 21d and the cylindrical lenses 25a, 25b, 25c, and 25d as essential components, the price of the optical scanning unit 10 increases. The disadvantage is that it takes up a large volume.

Accordingly, the present invention has been made in view of the above, and employs a Surface Emitting Laser (SEL) array, which is a laser diode that irradiates light in the stacking direction. f-θ The object of the present invention is to provide a photonic device for a color image output device having a simplified configuration and reduced volume by excluding the lens.

1 is a schematic view showing a light scanning unit for a conventional color image output device.

Figure 2 is a schematic view showing a light scanning unit for a color image output device according to an embodiment of the present invention.

3 is a schematic cross-sectional view showing the light source module of FIG.

4 is a schematic perspective view of the light source of FIG. 3;

Figure 5 is a schematic view showing a light scanning unit for a color image output device according to another embodiment of the present invention.

FIG. 6 is a schematic perspective view of the light source of FIG. 5; FIG.

<Explanation of symbols for main parts of the drawings>

40.Photosensitive belt 41a, 41b, 41c ... roller

42a, 42b, 42c, 42d ... Developing unit 44a, 44b, 44c, 44d ...

46 ... Static eliminator 48 ... Transfer unit

50 ... Gwangju Unit 51,51 '... Light source module

52 ... base 54 ... housing

56 ... collimating lens 57 ... lead frame

60,60 '... surface optical laser arrays SEL1, SEL2, SEL3, SEL4 ... surface optical laser

61,61 '... substrate 62,62' ... bottom reflector

63,63 '... active layer 64,64' ... upper reflector layer

65,65 '... electrode layer 65a, 65a' ...

67,67 '... Blocker 71 ...

73 ... hologram disc 75a to 79d ...

81a to 81d.Bending mirror 83a to 83d.Hologram element

In order to achieve the above object, the present invention provides a substrate, and a substrate, in the optical scanning unit for a color image output device for scanning a plurality of scanning lines so that an electrostatic latent image corresponding to each color is formed on the image surface of the photosensitive medium. A light source module disposed adjacent to each other and having a surface light laser array for emitting at least two lights in a stacking direction; A drive source for providing a rotational force; A hologram disk rotatably installed at the drive source, the hologram disk diffraction-transmitting each of the plurality of light incident from the light source module in different paths, and deflecting the plurality of incident light; And light path converting means for converting the traveling path of the incident light so that the plurality of light deflected and scanned from the hologram disk form a parallel scanning line on the image plane, and to secure the traveling path of the light corresponding to each color. It features.

Hereinafter, with reference to the accompanying drawings will be described in detail preferred embodiments of the optical scanning device for a color image output apparatus according to the present invention.

Referring to FIG. 2, the optical scanning unit according to the exemplary embodiment of the present invention is employed as a component of the color image output device to form an electrostatic latent image necessary for development on a photosensitive medium.

In the present embodiment, a color laser printer which forms and prints an image using a combination of four colors with the above-described color image output device will be described as an example. This color laser printer is supported by rollers 41a, 41b and 41c, and is provided with a photosensitive belt 40 provided to run on a circulation track, and a charger 44a for charging the photosensitive belt 40 to a predetermined potential ( 44b) 44c, 44d, and a photonic yarn unit 50 for scanning four scanning lines on the photosensitive belt 40 so as to correspond to each color to form an electrostatic latent image, and a photonic yarn unit 50. Development units 42a, 42b, 42c, 42d for developing the electrostatic latent image area, transfer units 48 for transferring the developed image to printing paper S, and potentials formed in the photosensitive belt 40 It is configured to include a static eliminator 46 to eliminate by the heat.

The optical fiber unit 50 is provided with a light source module 51 for emitting at least two or more light, a drive source 71 for providing a rotational force, rotatably installed in the drive source 71 and in the light source module 50 A hologram disk 73 for diffracted transmission of each of the plurality of incident light beams through different paths to deflect and scan the plurality of incident light beams; and a scanning line parallel to the image plane of the photosensitive belt 40 to secure an optical path of the scanned light; It is configured to include a light path conversion means to be formed.

The light source module 50 includes first and second light source modules 51a and 51b which generate and emit two lights L1 and L2 and two lights L3 and L4, respectively.

Referring to FIG. 3, each of the first and second light source modules 51a and 51b is disposed adjacent to each other on the substrate 61 and on the substrate 61 to emit at least two or more lights in the stacking direction. It includes a surface light laser array 60 consisting of two surface emitting lasers (SEL1, SEL2).

In addition, the first and second light source modules 51a and 51b may include a base 52 on which the substrate 61 is installed, and the base 61 to surround the substrate 61 and the surface light laser array 60. It is preferable to include a housing 54 installed on the 52 and having a window 54a through which the light irradiated from the surface light laser array 60 is emitted. In this case, a plurality of lead frames 57 wire-bonded with the substrate 61 and the surface light lasers SEL1 and SEL2 to drive the surface light lasers SEL1 and SEL2 are formed through the base 52. It is. In addition, the first and second light source modules (51a, 51b) are installed in the window 54a collimating lens to focus the divergent light emitted from the surface light laser array 60 to be parallel light ( It is preferred to further include 56).

Referring to FIG. 4, the surface light laser array 60 includes two surface light lasers SEL1 and SEL2 disposed adjacent to the same substrate 61.

The surface light lasers SEL1 and SEL2 are one of semiconductor lasers. Unlike the edge light emitting lasers emitting light to the side, the surface light lasers SEL1 and SEL2 emit light in the stacking direction of the semiconductor material layer, thereby forming an array structure on the same substrate 61. There is an advantage that the arrangement is easy. Further, since the cross-sectional shape of the light emitted from the surface light lasers SEL1 and SEL2 remains circular, there is an advantage that beam shaping is unnecessary. The two surface light lasers SEL1 and SEL2 include a lower reflector layer 62, an active layer 63, an upper reflector layer 64, and an electrode layer 65 sequentially stacked on the substrate 61. . An emission window 65a is formed in the electrode layer 65 through which the light generated by the active layer 63 and transmitted through the upper reflector layer 64 is emitted.

The lower reflector layer 62 and the upper reflector layer 64 are made of impurity semiconductor materials of different types. For example, the lower reflector layer 62 may be an n-type semiconductor material and the upper reflector layer 64 may be a p-type semiconductor material, or vice versa.

Each of the lower reflector layer 62 and the upper reflector layer 64 is approximately 99% It has the above high reflectance, reflects most of the light generated in the active layer 63, and transmits only a portion of the light. The electrode layer 65 is made of a metal having excellent electrical conductivity, and a positive voltage is applied to the substrate 61 through the lead frame 57.

Here, the two surface light lasers SEL1 and SEL2 are manufactured in the same process, and the two surface light lasers SEL1 and SEL2 are electrically insulated by the blocking plate 67 formed thereon, and according to a driving signal applied from the outside. Driven independently.

In the surface light laser array 60 configured as described above, the spacing between the exiting lights L1 and L2 and the spacing between the exiting lights L3 and L4 are preferably within several tens of micrometers. Therefore, when the diffraction angle does not greatly deviate when incident on the hologram disk 73 to cause diffraction, there is an advantage that the hologram pattern of the hologram disk 73 is easily formed.

Referring to FIG. 5, the hologram disk 73 is composed of a plurality of sectors 73a each having a hologram pattern, and the driving source 71 forms scan lines corresponding to the number of sectors in one rotation. . As described above, when the first and second light source modules 51a and 51b are provided, the two lights L1 and L2 irradiated from the first light source module 51a are always one sector of the hologram disk 73. Incident on the second light source module 51b and incident on the other sector of the hologram disk 73.

The optical path converting means has four optical paths between the light source module 51 and the image surface of the photosensitive belt 40 having the same length, and the scanning line is perpendicular to the image surface of the photosensitive belt 40. To be incident. To this end, the optical path converting means reflects each of the plurality of light deflected and scanned by the hologram disk 73 in a predetermined direction to secure a traveling path of the light corresponding to each color (75a, 75b) ( 75c) 75d, 77a, 77b, 77c, 77d, 79a, 79b, 79c, 79d and focused reflection of each incident light via the planar mirrors 75a to 79d. Hologram elements 83a for diffracting a plurality of curved mirrors 81a, 81b, 81c, 81d and scanning beams reflected from the curved mirrors 81a to 81d in a direction substantially perpendicular to the photosensitive belt 40. ), 83b, 83c, and 83d.

In order to secure the optical path of the plane mirrors (75a ~ 79d), Figure 3 is provided with three sheets for each color, for example, but in consideration of the space and size of the device in which the optical unit 50 is employed It is also possible to change the number of sheets and batches.

The curved mirrors 81a to 81d focus light diffracted by the hologram disk 73 to maintain parallel scan lines. The hologram elements 83a to 83d diffract the incident scanning light by a predetermined angle so as to be directed in a direction perpendicular to the image plane. Here, although not shown, the hologram elements 83a to 83d may be integrally formed on the curved mirrors 81a to 81d. That is, the hologram element may be replaced by forming a predetermined hologram pattern on the curved mirror.

Hereinafter, the operation of the optical scanning unit for the color image output device configured as described above will be described with reference to two lights emitted from the first light source module as an example.

The two lights L1 and L2 irradiated from the surface light laser array 60 constituting the first light source module 51a are focused by collimating lenses 56 installed in the first light source module 51a to become parallel light. , One sector of the hologram disk 73 is spaced apart from each other by approximately tens of micrometers apart. The hologram disk 73 is rotated by the driving source 71 to diffract and transmit incident light by a predetermined width. L1 of the light beams scanned through the hologram disk 73 is incident on the photosensitive belt via the planar mirrors 75a, 77a and 79a, the curved mirror 81a and the hologram element 83a, and L2. Is incident on another position of the photosensitive belt via the planar mirrors 75b, 77b and 79b, the curved mirror 81b and the hologram element 83b to form a scan line. In this case, incident scan lines are parallel to each other.

6 and 7, the optical scanning unit according to another embodiment of the present invention is characterized in that one light source module is adopted.

The light source module 51 'is a surface light laser array having a substrate 61' and four surface light lasers SEL1, SEL2, SEL3, and SEL4 disposed adjacent to each other on the substrate 61 '( 60 '). The surface light lasers SEL1, SEL2, SEL3, and SEL4 are stacked on the same substrate 61 ′ by one process and electrically insulated by the blocking plate 67 ′. The surface light laser may include a lower reflector layer 62 ', an active layer 63', an upper reflector layer 64 ', and an emission window 65a' sequentially stacked on the substrate 61 '. It is comprised including the electrode layer 65 'which has. Such a configuration is as described with reference to the embodiment, so a detailed description thereof will be omitted. On the other hand, the light source module 51 ′ preferably further includes a base on which the substrate 61 ′ is installed, a collimating lens, and a housing.

The light L1, L2, L3, L4 scanned by the light source module 51 'is scanned in one sector of the hologram disk 73, and the optical path is converted by the optical path converting means to be incident on the photosensitive belt 40. Here, since the hologram disk and the optical path converting means are substantially the same as those described with reference to the exemplary embodiment, detailed description thereof will be omitted.

As described above, by using the surface light laser array, a light having a circular cross-sectional shape is emitted, so that no means such as a cylindrical lens for beam shaping is necessary, and the distance between the two lights L1 and L2 is within several tens of micrometers. Since it can be narrowed, the hologram pattern of the said hologram disk is easy. Also, f-θ By excluding the lens, the space can be reduced and the cost can be saved.

In addition, when one light source module is used, since four lights incident on the hologram disk are adjacent to each other, optical alignment is easy and the light source module can be miniaturized.

Claims (11)

In the optical scanning unit for a color image output device for scanning a plurality of scanning lines to form an electrostatic latent image corresponding to each color on the image surface of the photosensitive medium, A light source module having a substrate and a surface light laser array disposed adjacent to each other on the substrate and emitting at least two or more lights in a stacking direction; A drive source for providing a rotational force; A hologram disk rotatably installed at the drive source, the hologram disk diffraction-transmitting each of the plurality of light incident from the light source module in different paths, and deflecting the plurality of incident light; And light path converting means for converting the traveling path of the incident light so that the plurality of light deflected and scanned from the hologram disk form a parallel scanning line on the image plane, and to secure the traveling path of the light corresponding to each color. Gwangju unit for color image output device characterized in that. The method of claim 1, wherein the light source module, A first light source module having a surface light laser array comprising a pair of surface light lasers which emit two light L1 and L2 and are adjacent to each other; And a second light source module having a surface light laser array comprising a pair of surface light lasers which emit two light L3 and L4 and are adjacent to each other. 2. The color image output according to claim 2, wherein a distance between the lights L1 and L2 emitted from the first light source module and a distance between the lights L3 and L4 emitted from the second light source module are approximately several tens of micrometers. Gwangju company unit for the device. The method of claim 2 or 3, wherein each of the first and second light source modules, A base on which the substrate is installed; And a housing installed on the base to surround the substrate and the surface light laser array, the housing having a window from which the light irradiated from the surface light laser is emitted. The method of claim 4, wherein the light source module, And a collimating lens installed on the window and focusing the divergent light emitted from the surface light laser array to be parallel light. The method of claim 1, wherein the light source module, And the surface light laser array, comprising four surface light lasers which emit four light L1, L2, L3, and L4 and are adjacent to each other. 7. The optical scanning unit for color image output devices according to claim 6, wherein an interval between adjacent lights among the lights L1, L2, L3, and L4 emitted from the light source module is about several tens of micrometers. The method of claim 6 or 7, wherein the light source module, A base on which the substrate is installed; And a housing installed on the base to surround the substrate and the surface light laser array, the housing having a window from which the light irradiated from the surface light laser is emitted. The method of claim 8, wherein the light source module, And a collimating lens installed on the window and focusing the divergent light emitted from the surface light laser array to be parallel light. The method of claim 1, wherein the optical path converting means, A plurality of planar mirrors for reflecting each of the plurality of light deflected and scanned in the hologram disk in a predetermined direction to secure a traveling path of light corresponding to each color; A plurality of curved mirrors for focusing and reflecting each of the light incident through the mirror; And a hologram element for diffracting the scanning beam reflected by the curved mirror in a direction substantially perpendicular to the photosensitive medium. The optical scanning unit for a color image output device according to claim 10, wherein the hologram element and the curved mirror are integrally formed by forming a predetermined hologram pattern on the curved mirror.