JP2004184428A - Multiple beam scanning device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To drastically reduce or eliminate the readjustment job of an adjusted light source device when the positions of beams are adjusted as a multibeam scanning device. <P>SOLUTION: A light source device 3 is provided with a plurality of light sources which emit beams B<SB>1</SB>and B<SB>2</SB>are furnished and the positions in subscanning direction of the beams B<SB>1</SB>and B<SB>2</SB>emitted from a plurality of light sources onto a face to be scanned are adjusted by adjusting the position in the turning direction of an opening means 4 which shields the peripheral part of the beams B<SB>1</SB>and B<SB>2</SB>emitted from the light source device 3. Thus, the readjustment job of the light source device 3 which is already adjusted is drastically reduced or eliminated when the positions of beams are finally adjusted as a multibeam scanning device 1. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a multi-beam scanning device for optically writing an image and an image forming apparatus.
[0002]
[Prior art]
In an image forming apparatus such as an electrophotographic printer, a digital copying machine, and a facsimile, which has a beam scanning device in an optical writing system for image formation, a pixel density of 300 dpi to 400 dpi, which is not very high, is mainly used. Was. However, in recent years, demands for image quality from the market are strict, and devices having a pixel density of more than 1200 dpi have been put on the market. In the future, high-density and high-speed devices are becoming mainstream. If a pixel density of 1200 dpi is to be realized, it is necessary to adjust the interval between the light beams in the sub-scanning direction on the surface to be scanned to be 21.2 μm. When a single beam is used to realize this, an optical deflector such as a polygon mirror must be operated at high speed. For this reason, problems such as noise and a rise in the temperature inside the machine are inevitable, and the cost of the optical deflector also increases. In addition, there is a method of realizing high density by lowering the rotation speed of the photoreceptor. However, this method lowers the printing speed and cannot cope with the higher speed.
[0003]
One method to meet this requirement is to scan a plurality of beams on the surface to be scanned at predetermined intervals in the sub-scanning direction. A multi-beam scanning device designed based on this method is expected to become the mainstream in the future. Can be By using this multi-beam scanning device, high-density, high-speed printing can be realized without operating the optical deflector at high speed.
[0004]
A light source device for multi-beam scanning includes a light source having a plurality of light-emitting portions and an optical lens for shaping light emitted from the light source, and the light source rotates around the optical axis of the optical lens. There is a light source device that can be used (see Patent Document 1).
[0005]
In order to achieve the same object, in a light source system in which light beams from a plurality of light sources (semiconductor lasers) are combined and emitted, a scanning pitch is adjusted by adjusting a rotational position of the combined light beam around an optical axis. There is a multi-beam scanning device that performs the adjustment (see Patent Document 2).
[0006]
[Patent Document 1]
JP-A-56-42248
[Patent Document 2]
JP-A-9-43523
[0007]
[Problems to be solved by the invention]
A light source device used for a multi-beam scanning device generally has a structure in which a plurality of light-emitting portions and an optical system for shaping a light beam of a beam emitted from these light-emitting portions are coupled. It is necessary to adjust the output optical axis adjustment and the focal position adjustment with high precision by using the jig. After performing such adjustment work, the light source device is attached to the housing of the multi-beam scanning device.
[0008]
On the other hand, the housing of the multi-beam scanning device is provided with an optical system including a cylinder lens system for shaping the luminous flux of light emitted from the light source device, an optical deflector, and a scanning imaging element. Since the individual elements of these optical systems have processing errors and mounting errors, and there is a limit to improving the processing dimensional accuracy and the mounting dimensional accuracy, the light source device is mounted on the housing of the multi-beam scanning device. In this state, the position accuracy of the plurality of beams in the sub-scanning direction may not be sufficiently obtained. In such a case, the light source device is removed from the housing, and readjustment of the light source device is forced in accordance with processing errors and mounting errors of optical systems other than the light source device. This is also true for the above-mentioned Patent Documents 1 and 2. Re-adjustment of the light source adjustment is not only an increase in the number of adjustments but also a complicated operation using a jig, so that it takes time and labor to assemble and adjust and causes an increase in man-hours.
[0009]
An object of the present invention is to make it possible to drastically reduce or eliminate the work of re-adjusting a light source device when adjusting a beam position as a multi-beam scanning device.
[0010]
An object of the present invention is to simplify the structure of the opening means.
[0011]
An object of the present invention is to prevent the occurrence of ghost during beam irradiation.
[0012]
[Means for Solving the Problems]
The multi-beam scanning device according to claim 1, wherein the light source device includes a plurality of light sources that emit the beam, an opening unit that shields a light beam peripheral part of the beam emitted from the light source device, and the light source device that emits the light beam from the light source device. An optical deflector for deflecting the beam passing through the aperture means in the main scanning direction of the surface to be scanned, and forming an image of the beam deflected by the optical deflector on the surface to be scanned at a constant scanning speed in the main scanning direction. A scanning image forming element, and a rotation position adjusting means for supporting the opening means so as to be freely rotatable around a center line along the optical axis of the beam and fixed at an arbitrary position.
[0013]
Therefore, by adjusting the position of the opening means in the rotation direction, it is possible to adjust the position of the beams emitted from the plurality of light sources onto the surface to be scanned in the sub-scanning direction. In this case, since the opening means for adjusting the position in the rotating direction is provided separately from the light source device, the work of re-adjusting the adjusted light source device at the time of final beam position adjustment as a multi-beam scanning device is performed. It can be drastically reduced or eliminated.
[0014]
Here, the light source device includes a configuration further including an optical system coupled to the light source (claim 2).
[0015]
According to a third aspect of the present invention, in the multi-beam scanning device according to the first aspect, a beam emitted from the light source device is converged in the sub-scanning direction between the light source device and the optical deflector. A cylinder lens that forms a long line image in the scanning direction is arranged.
[0016]
Therefore, it is possible to obtain the same effect as that of the first aspect, and it is possible to regulate the beam interval in the sub-scanning direction with high accuracy.
[0017]
According to a fourth aspect of the present invention, in the multi-beam scanning device according to the first aspect, the opening means includes a first opening member for shielding a peripheral portion of the light beam in the sub-scanning direction of the beam, and a light beam in the main scanning direction of the beam. A second opening member for shielding the peripheral portion from light, wherein the rotation position adjusting means supports at least one of the first opening member and the second opening member so as to be freely rotatable and freely fixed at an arbitrary position. It is configured to
[0018]
Therefore, by adjusting the position of the first opening member or the second opening member in the rotation direction, it is possible to adjust the position of the beams emitted from the plurality of light sources onto the surface to be scanned in the sub-scanning direction. It becomes. In this case, since the first opening member or the second opening member for adjusting the position in the rotation direction is provided separately from the light source device, it has already been adjusted in the final beam position adjustment as the multi-beam scanning device. It is possible to drastically reduce or eliminate the work of readjusting the light source device.
[0019]
According to a fifth aspect of the present invention, in the multi-beam scanning device according to the fourth aspect, the rotation position adjusting means is formed on a part of the housing to allow the first opening member or the second opening member to be formed. It has a support part that supports it rotatably.
[0020]
Therefore, the same effect as the fourth aspect can be obtained. Further, since the supporting portion of the turning position adjusting means is formed in a part of the housing, the number of components constituting the turning position adjusting means can be reduced.
[0021]
According to a sixth aspect of the present invention, in the multi-beam scanning device according to the fourth aspect, one of the first opening member and the second opening member is supported by the rotation position adjusting means, and the other is provided by the other. The housing is formed integrally with a part of the housing.
[0022]
Therefore, the same effect as the fourth aspect can be obtained. Further, since the first opening member or the second opening member that does not adjust the rotation position is formed integrally with a part of the housing, the structure can be simplified.
[0023]
According to a seventh aspect of the present invention, in the multi-beam scanning device according to any one of the fourth to sixth aspects, the first aperture member and the second aperture member have emission holes provided for shaping a beam. And an opening shape which is difficult to ghost.
[0024]
Therefore, it is possible to obtain the same effect as that of any one of the fourth to sixth aspects of the invention. Further, even when the thickness of the housing is large, it is possible to prevent the occurrence of ghost during beam irradiation.
[0025]
According to an eighth aspect of the present invention, in the multi-beam scanning device according to the seventh aspect, a gradient is provided on an inner surface of the emission hole so that a light beam spreads toward a beam emission direction.
[0026]
Therefore, it is possible to obtain the same effect as that of the seventh aspect only by forming a gradient on the inner surface of the exit hole.
[0027]
According to a ninth aspect of the present invention, in the multi-beam scanning device according to the first aspect, an aperture having an emission hole for shaping a beam emitted from the light source is integrally formed in a part of a housing of the light source device. Have been.
[0028]
Therefore, the same effect as the first aspect can be obtained. Further, the aperture can be manufactured at low cost by using a part of the housing of the light source device.
[0029]
According to a tenth aspect of the present invention, in the multi-beam scanning device according to the ninth aspect, the emission hole of the aperture is formed in an opening shape that is difficult to ghost.
[0030]
Therefore, the same effect as the ninth aspect can be obtained. Furthermore, in the case where an aperture is manufactured using a part of the housing of the light source device, even when the thickness of the housing is large, it is possible to prevent the occurrence of ghost at the time of beam irradiation.
[0031]
According to an eleventh aspect of the present invention, in the multi-beam scanning device according to the tenth aspect, an inner surface of the emission hole is provided with a gradient such that a light beam spreads toward a beam emission direction.
[0032]
Therefore, it is possible to obtain the same effect as that of the tenth aspect only by forming a gradient on the inner surface of the exit hole.
[0033]
An image forming apparatus according to a twelfth aspect includes the multi-beam scanning device according to any one of the first to eleventh aspects, and an image forming unit that forms an image based on a beam scanned from the multi-beam. .
[0034]
Therefore, it is possible to provide an image forming apparatus capable of obtaining the same effect as the invention according to any one of the first to eleventh aspects.
[0035]
BEST MODE FOR CARRYING OUT THE INVENTION
The configuration of the multi-beam scanning device according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a plan view showing an example of a multi-beam scanning device, FIG. 2 is a perspective view showing a beam scanning state of the multi-beam scanning device, FIG. 3 is an exploded perspective view of a light source device, and FIG. It is an exploded perspective view showing a relation with a means.
[0036]
As shown in FIG. 1, the multi-beam scanning device 1 includes a flat housing 2. The housing 2 has a light source device 3, an opening means (beam shaping means) 4 for shielding a peripheral portion of a light beam of a beam emitted from the light source device 3, and a beam passing through the opening means 4 converging in the sub-scanning direction. A cylinder lens 5 for forming a linear image long in the main scanning direction, an optical deflector 6 for deflecting a beam passing through the cylinder lens 5 in the main scanning direction, and a beam deflected by the optical deflector 6 There are provided scanning imaging elements 7, 8, 9 for forming an image on a surface to be scanned, which will be described later, with a constant scanning speed in the main scanning direction, and a mirror 10 for reflecting a beam. The scanning imaging elements 7, 8, and 9 are optical elements that scan the surface to be scanned at a constant speed in the main scanning direction, and the imaging point and the image plane by the cylinder lens 5 are conjugated in the sub-scanning direction. And an optical element having a surface tilt correction effect. The optical deflector 6 has a known configuration in which a beam is scanned by each reflecting surface 6b of a polygon mirror 6a driven by a motor (not shown). The upper surface of the housing 2 is closed by a cover (not shown), and a window (not shown) for projecting a beam reflected by the mirror 10 is formed on the lower surface.
[0037]
The light source device 3 includes laser diodes 11 and 12 as a plurality of light sources, and collimator lenses 13 and 14 as optical systems coupled to the laser diodes 11 and 12 as main components. That is, the multi-beam scanning device 1 outputs the beam B emitted by the laser diodes 11 and 12. ₁ , B ₂ Are collimated by the collimator lenses 13 and 14, and their beams B ₁ , B ₂ Is shaped by the aperture means 4 so as to have a desired spot diameter. ₁ , B ₂ Is converged in the sub-scanning direction by the cylinder lens 5, deflected in the main scanning direction by the rotation of the polygon mirror 6 a, transmitted through the scanning imaging elements 7, 8, 9, reflected by the mirror 10, and reflected on the surface of the photoconductor 15. That is, it is configured to irradiate the surface to be scanned 16.
[0038]
Next, the configuration of the light source device 3 will be described with reference to FIG. The laser diodes 11 and 12 emit a beam B in the configuration of the light source device 3. ₁ , B ₂ Are spaced at a predetermined interval in the main scanning direction, and the beam B near the deflection point on the reflection surface 6b of the polygon mirror 6a. ₁ , B ₂ Are supported so that the distance between them is 0 mm. Specifically, the laser diodes 11 and 12 connected to the drive circuit board 17 are press-fitted into the laser diode holder 19 which is coupled to the collimator lens holder 18 by screws 19a. The collimator lenses 13 and 14 are fixed to the collimator lens holder 18 in a pressed state by a leaf spring (not shown) or the like. The collimator lens holder 18 has a boss 21 provided in an upright state at the center thereof loosely fitted into a support hole 22 formed in a bracket 20 serving as a housing of the light source device 3. Attached to. The bracket 20 includes a beam B emitted from the laser diodes 11 and 12. ₁ , B ₂ Has openings 24 and 25 formed therethrough to pass through, and four mounting shafts 26 protruding from four corners. At four corners of the drive circuit board 17, mounting holes 27 are formed. The drive circuit board 17 is connected to the bracket 20 by inserting the mounting screws 28 into the mounting holes 27 and screwing the mounting screws 28 to the tip of the mounting shaft 26.
[0039]
The light source device 3 according to the present embodiment loosens the screw 23 and adjusts the position of the collimator lens holder 18 in the rotation direction about the boss 21 so that the laser diodes 11 and 12 on the surface 16 to be scanned 16 are adjusted. The beam irradiation position can be adjusted from above.
[0040]
The feature of the present invention is that the aperture means 4 arranged between the light source device 3 and the optical deflector 6 ₁ , B _Two Of the laser diodes 11 and 12 on the surface 16 to be scanned by rotating the laser beam to a desired position about a center line along the optical axis of ₁ , B _Two Is intended to adjust the irradiation position in the sub-scanning direction.
[0041]
Here, the configuration of the opening means 4 and the support structure of the opening means 4 will be specifically described with reference to FIG. The opening means 4 includes a first opening member 4a formed in the shape of a disk, a second opening member (not shown) opposed to the back side thereof, and a cylinder for fittingly holding them. And the like-shaped member 29. In this example, the first opening member 4a has the beam B ₁ , B _Two Of the light beam in the sub-scanning direction (the vertical direction in FIG. 4). ₁ , B _Two Is formed. The second aperture member (not shown) is a beam B ₁ , B _Two Of the light beam in the main scanning direction of FIG. ₁ , B _Two Is formed.
[0042]
As shown in FIG. 4, a support wall 31 is formed integrally with a part of the housing 2 of the multi-beam scanning device 1, and the support wall 31 is provided with a first opening member 4a and a second opening member together with a cylindrical member. A V-shaped notch-shaped support portion 32 for rotatably supporting the member 29 is formed. A support wall 31 having the support portion 32 formed thereon, a leaf spring 33 for pressing the outer periphery of the cylindrical member 29 against the bottom surface of the support portion 32, and a screw 34 for fixing both ends of the leaf spring 33 to the support wall 31. Thus, a turning position adjusting means 35 that supports the opening means 4 so as to be freely rotatable and freely fixed at an arbitrary position is configured. The rotation center of the opening means 4 in this case is the beam B ₁ , B _Two Is a center line along the optical axis of. In the present embodiment, the plurality of light sources are two laser diodes 11 and 12, and their optical axes are inclined in a direction approaching each other as they go toward the emission direction. Is beam B ₁ , B _Two Beam B along the optical axis of ₁ , B ₂ , Not parallel to the optical axis of the beam B ₁ , B _Two Is a center line that divides the angle of into two. Note that the tubular member 29 may be omitted, and the first opening member 4a and the second opening member may be directly pressed against the bottom of the support portion 32 by the leaf spring 33.
[0043]
In such a configuration, by loosening the screw 34 and rotating the cylindrical member 29 to adjust the position of the opening means 4 (the first opening member 4a and the second opening member) in the rotation direction, Beams B emitted from the plurality of laser diodes 11 and 12 onto the surface to be scanned 16 ₁ , B _Two Can be adjusted in the sub-scanning direction. In this case, since the opening means 4 for adjusting the position in the rotation direction is provided separately from the light source device 3, the beam B ₁ , B _Two In the position adjustment in the sub-scanning direction, the operation of re-adjusting the adjusted light source device 3 can be drastically reduced or eliminated.
[0044]
Further, a beam B emitted from the light source device 3 is provided between the light source device 3 and the optical deflector 6. ₁ , B _Two Is converged in the sub-scanning direction to form a long line image in the main scanning direction, so that the beam interval in the sub-scanning direction can be further precisely regulated.
[0045]
Further, as shown in FIG. 4, the rotation position adjusting means 35 is formed on the support wall 31 which is a part of the housing 2 and rotatably supports the first opening member 4a or the second opening member. Since the support portion 32 is provided, the number of components constituting the rotation position adjusting means 35 can be reduced.
[0046]
In the present embodiment, the laser diodes 11 and 12 each emitting one beam are used as the light source. Alternatively, a plurality of semiconductor lasers emitting a plurality of beams may be used as the light source.
[0047]
Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted. FIG. 5 is a horizontal sectional view showing an example of a second opening member constituting the opening means. In the above embodiment, both the first opening member 4a and the second opening member constituting the opening means 4 are supported by the turning position adjusting means 35 (see FIG. 4) so that the turning position can be adjusted. In this embodiment, the beam B is applied to the wall surface 36 which is a part of the housing 2. ₁ , B _Two This is an example in which a second opening member 4b (not shown in FIG. 4) is formed integrally with a wall surface 36 which is a part of the housing 2 by forming an emission hole 30 for emitting light. If it is not necessary to adjust the rotation position of the first opening member 4a in FIG. 4, the first opening member 4a may be formed integrally with the wall surface 36. In that case, the second opening member 4b may be supported so that the rotation position can be adjusted.
[0048]
The exit hole 30 shown in FIG. 5 is formed in an opening shape in which ghost is unlikely to occur. Specifically, beam B ₁ , B _Two The inner surface is sloped so that the light beam spreads toward the emission direction of the light. By doing so, even when the thickness of the housing 2 is large, it is possible to prevent ghost from occurring at the time of beam irradiation. The provision of a gradient on the inner surface of the exit hole 30 in order to prevent ghost from occurring can be applied to the exit hole 30 shown in FIG.
[0049]
Next, a third embodiment of the present invention will be described with reference to FIG. The same parts as those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted. FIG. 6 is a perspective view of a housing included in the light source device 3. In this embodiment, a beam B is provided on a bracket 20 serving as a housing of the light source device 3 instead of the openings 24 and 25 shown in FIG. ₁ , B _Two This is an example in which an aperture 37 is formed integrally with the bracket 20 by forming an exit hole 30 for shaping the aperture.
[0050]
Therefore, the aperture 37 can be manufactured at low cost using a part of the housing (bracket) 20 of the light source device 3. Accordingly, the configuration of the opening member for adjusting the rotational position, which is arranged between the light source device 3 and the light deflector 6, can be simplified. The exit hole 30 shown in FIG. 6 may have a shape that is difficult to ghost, for example, by giving a gradient to the inner surface similarly to the exit hole 30 as shown in FIG.
[0051]
Next, an image forming apparatus including the multi-beam scanning device 1 described above will be described with reference to FIG. 7, reference numeral 100 denotes an image forming apparatus. The apparatus main body 101 of the image forming apparatus 100 includes a multi-beam scanning device 1, an image forming unit 102, a paper feeding unit 103, and a paper feeding unit 103. A paper transport path 105 is provided. The paper discharge unit 104 is formed on the upper surface of the apparatus main body 101.
[0052]
The paper feed unit 103 has a plurality of paper feed trays 106 and is configured to be able to feed paper from the selected paper feed tray 106.
[0053]
The image forming unit 102 develops the electrostatic latent image written on the scanned surface 16 which is the surface of the photoconductor 15 by the multi-beam scanning device 1 by the developing unit 107, and transfers the developed image to the fed paper. This is a known electrophotographic configuration in which the image is transferred by a device 108 and the transferred image is fixed by a fixing device 109.
[0054]
In the image forming apparatus 100, when the electrostatic latent image is written on the photoconductor 15 by the multi-beam scanning device 1, as described above, the beams emitted from the plurality of laser diodes 11 and 12 onto the surface 16 to be scanned are It is possible to adjust the position in the sub-scanning direction. Further, when adjusting the position of the beam in the sub-scanning direction, the operation of re-adjusting the adjusted light source device 3 can be drastically reduced or eliminated.
[0055]
【The invention's effect】
The multi-beam scanning device according to claim 1 or 2, further comprising a light source device provided with a plurality of light sources for emitting a beam, and rotation of an opening means for blocking a peripheral portion of a light beam of the beam emitted from the light source device. By adjusting the position in the direction, the position in the sub-scanning direction of the beam emitted from the plurality of light sources onto the surface to be scanned can be adjusted. In this case, since the opening means for adjusting the position in the rotating direction is provided separately from the light source device, the work of re-adjusting the adjusted light source device at the time of final beam position adjustment as a multi-beam scanning device is performed. Can be drastically reduced or eliminated.
[0056]
According to a third aspect of the present invention, in the multi-beam scanning device according to the first aspect, a beam emitted from the light source device is converged in the sub-scanning direction between the light source device and the optical deflector in the main scanning direction. Since the cylinder lens that forms a long line image is provided, the same effect as that of the first aspect can be obtained, and the beam interval in the sub-scanning direction can be regulated with high accuracy.
[0057]
According to a fourth aspect of the present invention, in the multi-beam scanning device according to the first aspect, the opening means shields a peripheral portion of the light beam in the sub-scanning direction of the beam, and a peripheral portion of the light beam in the main scanning direction of the beam. A second opening member for shielding the portion from light, and the rotation position adjusting means supports at least one of the first opening member and the second opening member so as to be rotatable and freely fixed at an arbitrary position. By adjusting the position of the first opening member or the second opening member in the rotation direction, the position of the beam emitted from the plurality of light sources onto the surface to be scanned in the sub-scanning direction is adjusted. can do. In this case, since the first opening member or the second opening member for adjusting the position in the rotation direction is provided separately from the light source device, it has already been adjusted in the final beam position adjustment as the multi-beam scanning device. Work for re-adjusting the light source device of the present invention can be drastically reduced or eliminated.
[0058]
According to a fifth aspect of the present invention, in the multi-beam scanning device according to the fourth aspect, the rotation position adjusting means is formed on a part of the housing to rotate the first opening member or the second opening member. Since the supporting portion is provided, the same effect as that of the fourth aspect can be obtained. Further, since the supporting portion of the turning position adjusting means is formed in a part of the housing, the number of components constituting the turning position adjusting means can be reduced.
[0059]
According to a sixth aspect of the present invention, in the multi-beam scanning apparatus according to the fourth aspect, one of the first opening member and the second opening member is supported by a rotation position adjusting means, and the other is provided by the housing. Since it is formed integrally in a part, the same effect as in claim 4 can be obtained. Further, since the first opening member or the second opening member that does not adjust the rotation position is formed integrally with a part of the housing, the structure can be simplified.
[0060]
According to a seventh aspect of the present invention, in the multi-beam scanning apparatus according to any one of the fourth to sixth aspects, the first aperture member and the second aperture member include an emission hole provided for shaping a beam, Since it is formed in an opening shape that is difficult to be ghosted, the same effect as any one of the inventions of claims 4 to 6 can be obtained. Further, even when the thickness of the housing is large, it is possible to prevent the occurrence of a ghost at the time of beam irradiation.
[0061]
According to an eighth aspect of the present invention, in the multi-beam scanning device according to the seventh aspect, since the exit hole has a gradient on its inner surface so that the light beam spreads toward the beam exit direction, the inner surface of the exit hole is The same effect as that of the seventh aspect can be obtained only by providing a gradient.
[0062]
According to a ninth aspect of the present invention, in the multi-beam scanning device according to the first aspect, an aperture having an emission hole for shaping a beam emitted from the light source is integrally formed in a part of a housing of the light source device. Therefore, the same effect as the first aspect can be obtained. Further, the aperture can be manufactured at low cost by using a part of the housing of the light source device.
[0063]
According to a tenth aspect of the present invention, in the multi-beam scanning device according to the ninth aspect, since the exit hole of the aperture is formed in an opening shape that is difficult to ghost, the same effect as that of the ninth aspect can be obtained. Furthermore, in the case where an aperture is manufactured using a part of the housing of the light source device, even when the thickness of the housing is large, it is possible to prevent the occurrence of a ghost at the time of beam irradiation.
[0064]
According to an eleventh aspect of the present invention, in the multi-beam scanning device according to the tenth aspect, the exit hole has a gradient on its inner surface so that the light beam spreads toward the beam emission direction. An effect similar to that of the tenth aspect can be obtained only by providing a gradient.
[0065]
Since the image forming apparatus according to the twelfth aspect includes the multi-beam scanning device according to any one of the first to eleventh aspects, the same effect as the invention according to the one of the first to eleventh aspects can be obtained. A possible image forming apparatus can be provided.
[Brief description of the drawings]
FIG. 1 is a plan view illustrating an example of a multi-beam scanning device according to a first embodiment of the present invention.
FIG. 2 is a perspective view showing a beam scanning state of the multi-beam scanning device.
FIG. 3 is an exploded perspective view of the light source device.
FIG. 4 is an exploded perspective view showing a relationship between the opening means and the rotation position adjusting means.
FIG. 5 is a horizontal sectional view showing an example of a second opening member constituting an opening means according to the second embodiment of the present invention.
FIG. 6 is a perspective view of a housing included in a light source device according to a third embodiment of the present invention.
FIG. 7 is an explanatory diagram illustrating an internal schematic structure of an image forming apparatus including a multi-beam scanning device.
[Explanation of symbols]
1 Multi-beam scanning device
2 Housing
3 Light source device
4 Opening means
4a First opening member
4b Second opening member
5 Cylinder lens
6 Optical deflector
7-9 scanning imaging element
13,14 Optical system
20 Light source device housing
30 Exit hole
31, 36 Part of the housing
32 Support
35 Rotational position adjusting means
37 Aperture
102 Image forming unit

Claims (12)

A light source device having a plurality of light sources for emitting a beam,
Opening means for blocking a light beam peripheral portion of a beam emitted from the light source device,
An optical deflector that deflects a beam emitted from the light source device and passing through the opening means in a main scanning direction of a surface to be scanned,
A scanning imaging element for imaging the beam deflected by the optical deflector on the surface to be scanned at a constant scanning speed in the main scanning direction,
Turning position adjusting means for supporting the opening means so as to be freely rotatable about a center line along the optical axis of the beam and to be freely fixed at an arbitrary position;
Multi-beam scanning device having a housing in a housing. The multi-beam scanning device according to claim 1, wherein the light source device further includes an optical system coupled to the light source. A cylinder lens that converges a beam emitted from the light source device in the sub-scanning direction and forms a line image long in the main scanning direction between the light source device and the optical deflector. 2. The multi-beam scanning device according to 1. The opening means has a first opening member that shields a light beam peripheral portion in a beam sub-scanning direction, and a second opening member that shields a light beam peripheral portion in a beam main scanning direction.
2. The multi-beam according to claim 1, wherein the rotation position adjusting unit is configured to support at least one of the first opening member and the second opening member so as to be freely rotatable and freely fixed at an arbitrary position. Scanning device. 5. The multi-unit according to claim 4, wherein said rotation position adjusting means has a support portion formed on a part of said housing and rotatably supporting said first opening member or said second opening member. Beam scanning device. 5. The multi-beam according to claim 4, wherein one of the first opening member and the second opening member is supported by the rotation position adjusting means, and the other is formed integrally with a part of the housing. Scanning device. The multi-beam scanning device according to claim 4, wherein an emission hole provided in the first opening member and the second opening member for shaping a beam is formed in an opening shape that is difficult to ghost. apparatus. 8. The multi-beam scanning device according to claim 7, wherein the exit hole has a gradient on an inner surface such that a light beam spreads toward a beam exit direction. The multi-beam scanning device according to claim 1, wherein an aperture having an emission hole for shaping a beam emitted from the light source is integrally formed in a part of a housing of the light source device. The multi-beam scanning device according to claim 9, wherein the emission hole of the aperture is formed in an opening shape that is difficult to ghost. The multi-beam scanning device according to claim 10, wherein the exit hole has a gradient on an inner surface such that a light beam spreads toward a beam exit direction. A multi-beam scanning device according to any one of claims 1 to 11,
An image forming unit that forms an image based on a beam scanned from the multi-beam,
An image forming apparatus comprising:

Images