JP3665868B2 - Optical beam scanning optical device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical beam scanning optical apparatus, and particularly relates to an optical beam scanning optical apparatus that is used as the image writing means of a laser printer or a digital copying machine.
[0002]
[Prior art]
As a light beam scanning optical device, a device in which a plurality of light beams are simultaneously condensed at different positions on a surface to be scanned and a plurality of lines are simultaneously written by one scanning is known. As a light source device for this type of device, a device in which light emitting points are arranged in a row has been conventionally used.
[0003]
[Problems to be solved by the invention]
However, in the conventional light source device, when the number of light emitting points is 3 or more, the distance from each light emitting point to the optical axis is different, and the light beam emitted from each light emitting point is substantially parallel light or The position of each light emitting point was not optically equivalent to the condenser lens that was shaped into one of the convergent lights. Therefore, the light emitted from the light emitting points (light emitting points away from the optical axis) arranged on both sides compared to the light beam emitted from the light emitting point arranged at the center (light emitting point substantially on the optical axis). There is a problem in that the state of condensing between the light beams varies due to a large amount of generation of aberration of the beam and the uniformity of the image is impaired.
[0004]
In addition, when the number of light emitting points is 3 or more, the positional relationship between the light emitting points is not equivalent, and the temperature rise of the light emitting point arranged in the center is larger than the light emitting points arranged on both sides, and the light beam There was also a problem that the amount of light in between varied.
[0005]
An object of the present invention is to provide a high yet light beam scanning optical apparatus in the uniformity of the image.
[0006]
[Means and Actions for Solving the Problems]
In order to achieve the above object, a light beam scanning optical apparatus according to the first invention comprises:
A light source having three or more light emitting points, a condensing lens for shaping a light beam emitted from the light emitting points into either substantially parallel light or convergent light, and means for rotating the light source about the optical axis; Each light beam emitted from the light emitting point is emitted from a position on a predetermined circumference substantially centering on the optical axis of the exit surface of the condenser lens, and each light emitted from the condenser lens A light source device having substantially equal beam aberrations ;
A deflector that deflects and scans the light beam emitted from the light source device;
A scanning optical element that scans the light beam emitted from the deflector in a line on the surface to be scanned;
Means for rearranging the order in the sub-scanning direction of the image data transmitted to the light emitting point in accordance with the rotation of the light source by the means for rotating the light source;
It is provided with.
[0007]
A light beam scanning optical apparatus according to the second invention is
A light source having three or more light emitting points, a condensing lens for shaping a light beam emitted from the light emitting points into either substantially parallel light or convergent light, and means for rotating the light source about the optical axis; Each light beam emitted from the light emitting point is emitted from a position on a predetermined circumference substantially centering on the optical axis of the exit surface of the condenser lens, and each light emitted from the condenser lens A light source device in which the beam has an emission angle substantially equal to the optical axis ;
A deflector that deflects and scans the light beam emitted from the light source device;
A scanning optical element that scans the light beam emitted from the deflector in a line on the surface to be scanned;
Means for rearranging the order in the sub-scanning direction of the image data transmitted to the light emitting point in accordance with the rotation of the light source by the means for rotating the light source;
It is provided with.
[0008]
A light beam scanning optical apparatus according to the third invention is
A light source having three or more light emission points, the light emission point being arranged on a circumference having a predetermined radius, and a substantially axisymmetric shape with respect to a straight line passing through the center of the light emission point of the light source, A light source device comprising: a condenser lens that shapes the light beam emitted from the light emitting point into either substantially parallel light or convergent light; and means for rotating the light source about an optical axis ;
A deflector that deflects and scans the light beam emitted from the light source device;
A scanning optical element that scans the light beam emitted from the deflector in a line on the surface to be scanned;
Means for rearranging the order in the sub-scanning direction of the image data transmitted to the light emitting point in accordance with the rotation of the light source by the means for rotating the light source;
It is provided with. Here, the substantially parallel light includes light that diverges slightly.
[0009]
With the above configuration, the position of each light emitting point is optically equivalent to the condensing lens, and the condensing state between the light beams is less likely to vary. Furthermore, by arranging the light emitting points of the light source at equal intervals on the circumference, the positional relationship between the light emitting points becomes equivalent, and variations in temperature rise between the light emitting points can be suppressed. In addition, since there is provided means for rearranging the order in the sub-scanning direction of the image data to be transmitted to the light emitting point in accordance with the rotation of the light source by the means for rotating the light source, the light emitting point interval of the light source in the sub-scanning direction is Apparently changed, the density of the image formed on the surface to be scanned is switched.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
It will be described below with reference to the accompanying drawings one embodiment of the fastening Ru light beam scanning optical apparatus in the present invention.
[0014]
In FIG. 1, the light beam scanning optical apparatus generally includes a light source unit 1, a cylindrical lens 11, a polygon mirror 12, three fθ lenses 13, 14, 15 and a cylindrical lens 16, a plane mirror 17, and a photosensitive drum. 25.
[0015]
The light source unit 1 includes a laser diode array 2 and a collimator lens 5. The collimator lens 5 has an axial symmetry shape, and the symmetry axis is disposed on the optical axis C of the scanning optical device.
[0016]
The laser diode array 2 has a substantially cylindrical shape, and has four light emitting points 2a, 2b, 2c, and 2d arranged on the outer edge at equal intervals of 90 ° as shown in FIG. Accordingly, the positional relationship between the light emitting points 2a to 2d is equivalent, and variations in temperature rise between the light emitting points 2a to 2d can be suppressed. As a result, the variation in the amount of light between the light beams emitted from the light emitting points 2a to 2d is reduced. Further, these light emitting points 2 a to 2 d are arranged on a circumference Q centered on the symmetry axis (optical axis C) of the collimator lens 5. With this configuration, the positions of the light emitting points 2 a to 2 d are optically equivalent to the collimator lens 5. Therefore, the light collection state between the light beams emitted from the light emitting points 2a to 2d is less likely to vary, and the uniformity of the image can be improved.
[0017]
As shown in FIG. 1, an output pinion 22 of a stepping motor 23 meshes with a rack 21 formed on the outer peripheral surface of the laser diode array 2. By rotating the stepping motor 23 forward or backward, the laser diode array 2 can rotate in the outer peripheral direction about the optical axis C. By this rotation, the four light emitting points 2a to 2d move around the optical axis C, and the condensing positions on the photosensitive drum 25 of the light beams emitted from the light emitting points 2a to 2d are adjusted, and the image The density is switched.
[0018]
The light beams B ₁ , B ₂ , B ₃ , B ₄ emitted from the laser diode array 2 are converted into parallel light (or convergent light) by the collimator lens 5, respectively. The light beams B _{1 to} B ₄ are emitted from positions on a predetermined circumference around the optical axis C of the emission surface of the collimator lens 5. The aberrations of the light beams B _{1 to} B ₄ emitted from the collimator lens 5 are substantially equal, and the light emitting points 2 a to 2 d of the light beams B _{1 to} B ₄ are relative to the optical surface of the collimator lens 5 as described above. Therefore, the influence of the aberration generated on each surface of the collimator lens 5 is also the same. As a result, an image with excellent uniformity can be obtained. The light beams B _{1 to} B ₄ are emitted from the collimator lens 5 at the same emission angle with respect to the optical axis C. Therefore, for example, as shown in FIG. 3, when the aperture 7 is arranged on the optical axis C at the back focal position of the collimator lens 5 and the diameters of the light beams B _{1 to} B ₄ are restricted, all the light beams B ₁ to B ₄ are arranged. B ₄ is always vignetted by the same amount by the aperture 7, and an image with excellent uniformity can be obtained. These effects are the same even when the laser diode array 2 is rotated in the outer peripheral direction by using the stepping motor 23 to change the positions of the light emitting points 2a to 2d.
[0019]
The light beams B _{1 to} B ₄ emitted from the collimator lens 5 reach the polygon mirror 12 through the cylindrical lens 11. The cylindrical lens 11 condenses the light beams B _{1 to} B ₄ in the form of a long line in the main scanning direction near the reflecting surface of the polygon mirror 12. The polygon mirror 12 is rotationally driven at a constant angular velocity in the direction of arrow a. Based on the rotation of the polygon mirror 12, the light beams B _{1 to} B ₄ are deflected and scanned at equal angular speeds on the respective reflecting surfaces, pass through the fθ lenses 13, 14, 15 and the cylindrical lens 16, and are reflected downward by the plane mirror 17. The Thereafter, the light beams B _{1 to} B ₄ form an image on the photosensitive drum 25 and scan in the arrow b direction. That is, in this optical system, four lines are simultaneously written in one scan.
[0020]
The fθ lenses 13, 14, and 15 have a function of correcting (distortion aberration correction) the main scanning speed on the photosensitive drum 25 at a constant speed with the light beams B _{1 to} B ₄ deflected at a constant angular speed by the polygon mirror 12. ing. Similar to the cylindrical lens 11, the cylindrical lens 16 has power only in the sub-scanning direction, and the two lenses 11 and 16 cooperate to correct the surface tilt error of the polygon mirror.
[0021]
The photosensitive drum 25 is driven to rotate at a constant speed in the direction of arrow c, and is subjected to main scanning in the direction of arrow b by the polygon mirror 12 and the fθ lenses 13, 14, and 15, and sub scanning in the direction of arrow c of the photosensitive drum 25. An image (electrostatic latent image) is written on the photosensitive drum 25.
[0022]
Hereinafter, the adjustment of the condensing position of the _four light beams B _{1 to} B ₄ radiated from the laser diode array 2 on the photosensitive drum 25 when the image density of the light beam scanning optical device is set to 400 dpi. An example will be described with reference to FIGS. 2, 4, and 5.
[0023]
As shown in FIG. 2, the laser diode array 2 is rotated in the outer circumferential direction using the stepping motor 23 so that the line connecting the light emitting point 2a and the optical axis C is 78.7 ° with respect to the main scanning direction. Moved. As a result, the light emitting points 2a to 2d are apparently arranged at unequal intervals in the sub-scanning direction, and the light beams B _{1 to} B ₄ emitted from the light emitting points 2a to 2d are as shown in FIG. On the photosensitive drum 25, the light is condensed at unequal intervals in the sub-scanning direction.
[0024]
That is, the gap in the sub-scanning direction of the light beam spot 30a~30d in on each of the photosensitive drums 25 of the light beam B ₁ .about.B _4, the light beam interval required from the image density of 400dpi p (= 63.4μm (= Approximately 63.5 μm, equivalent to 400 dpi) is “1”, the distance between the spots 30a and 30d and the distance between the spots 30b and 30c are “2”, and the distance between the spots 30d and 30b is “1”.
[0025]
Incidentally, in the laser diode array 2, the positions of the light emitting points 2a to 2d are different in the main scanning direction. Therefore, the writing positions of the light emitting points 2a to 2d when the light emitting points 2a to 2d emit light simultaneously are shifted in the main scanning direction. Therefore, in order to align the writing positions of the light emitting points 2a to 2d, it is necessary to delay the drive start timing of the light emitting points 2a, 2c, and 2d with reference to the light emitting point 2b. That is, as shown in FIG. 5, the reference light emission point 2b is started to be driven based on the image data after a time t ₀ after detecting the vertical synchronization signal for determining the print start position for each scan. The light emitting points 2a, 2c, and 2d are further driven based on the image data after the delay times t ₁ , t ₂ , and t ₃ . In this way, a light beam scanning optical device with a uniform writing position is obtained.
[0026]
Next, writing of an image on the photosensitive drum 25 by the laser diode array 2 adjusted as described above will be described with reference to FIGS.
As shown in FIG. 6, the light beams B _{1 to} B ₄ emitted from the light emitting points 2 a to 2 d form beam spots 30 a to 30 d on the photosensitive drum 25 at unequal intervals in the sub-scanning direction. Interlaced scanning is performed at these beam spots 30a to 30d. Interlaced scanning is different from scanning at the first, second,... At the same time in order from the front end of the image with a plurality of beam spots (see FIGS. 14 and 16). The scanning line located between the lines is scanned by the previous scanning. That is, in the first scan, the remaining light emitting points 2b to 2d are lighted without lighting the light emitting point 2a. At this time, the light emitting point 2d is driven based on the image data of the scanning line 1, the light emitting point 2b is driven based on the image data of the scanning line 2, and the light emitting point 2c is driven based on the image data of the scanning line 4. (See FIG. 7). The reason why the light emitting point 2a is not turned on is that a scan missing portion is not generated at the front end of the image.
[0027]
In the second scan, all the light emitting points 2a to 2d are turned on. At this time, the light emitting point 2a is driven based on the image data of the scanning line 3, the light emitting point 2d is driven based on the image data of the scanning line 5, and the light emitting point 2b is driven based on the image data of the scanning line 6. The light emitting point 2c is driven based on the image data of the scanning line 8 (see FIG. 7). Thereafter, scanning is repeated for the third time, the fourth time,...
[0028]
Thus, the four light beam spots 30a to 30d are scanned while the scanning line scanned by the spot 30c during the previous scanning skips over the scanning line scanned by the spot 30a during the subsequent scanning. An image is formed on the body drum 25. Therefore, even if the light beam spots 30a to 30d are unequally spaced in the sub-scanning direction, an image can be formed on the photosensitive drum 25 without causing double writing or missing scanning. In this way, by setting the positions of the light beam spots 30a to 30d on the photosensitive drum 25 at unequal intervals in the sub-scanning direction, the degree of freedom in setting the intervals between the light emitting points 2a to 2d can be increased. The shape and arrangement of the polygon mirror 12 and the fθ lenses 13 to 15 can be optimally set without restriction.
[0029]
Here, as shown in FIG. 8, the drive circuit block of the laser diode array 2 is roughly composed of a RAM 41 for storing image data, a controller 42 for controlling the laser diode array 2, and a light emitting point 2a. It is comprised with the driver 43 for driving -2d. When a command signal for rearranging image data from the host computer 40 is input to the RAM 41 via the interface (I / F), the image data arranged and stored in the RAM 41 in order from the scanning line 1 is stored for each scan. Are taken out in the order shown in FIG. In the controller 42, each image data is output by the delay circuit 42a after a predetermined delay time. The image data signals output from the controller 42 after being sequentially delayed are transmitted to the drivers 43, and each driver 43 sequentially drives the corresponding light emitting points 2a to 2d.
[0030]
Next, FIGS. 9 to 12 show a second example of adjusting the condensing position of the light beams B _{1 to} B _{4 on} the photosensitive drum 25 when the image density of the light beam scanning optical device is switched to 600 dpi. The description will be given with reference.
As shown in FIG. 9, the laser diode array 2 is rotated in the outer peripheral direction using the stepping motor 23 so that the line connecting the light emitting point 2a and the optical axis C is 66.8 ° with respect to the main scanning direction. Moved. Thus, the light emitting point 2a~2d is now arranged at unequal intervals in apparent on a sub-scanning direction, the light beam B ₁ .about.B ₄ which are respectively emitted from the light emitting point 2a~2d are shown in FIG. 10 As described above, the light beam spots 30a to 30d are formed on the photosensitive drum 25 at unequal intervals in the sub-scanning direction. The distance between the spots 30a to 30d is the distance between the spots 30a and 30d and the spot 30d when the light beam interval p (= 42.4 μm = approximately 42.3 μm, equivalent to 600 dpi) required from an image density of 600 dpi is set to “1”. The interval between 30b and 30c is “2”, and the interval between the spots 30d and 30b is “3”.
[0031]
Next, writing of an image on the photosensitive drum 25 by the laser diode array 2 adjusted as described above will be described with reference to FIG.
In the first scan, the light emitting points 2b and 2c are turned on without turning on the light emitting points 2a and 2d. At this time, the light emitting point 2b is driven based on the image data of the scanning line 2, and the light emitting point 2c is driven based on the image data of the scanning line 4 (see FIG. 12). In the second scan, all the light emitting points 2a to 2d are turned on. At this time, the light emitting point 2a is driven based on the image data of the scanning line 1, the light emitting point 2b is driven based on the image data of the scanning line 6, and the light emitting point 2c is driven based on the image data of the scanning line 8. The light emitting point 2d is driven based on the image data of the scanning line 3 (see FIG. 12). Such rearrangement of image data is performed according to a command signal from the host computer 40 shown in FIG. 8 as described above. Thus, an image is formed on the photosensitive drum 25 by performing interlaced scanning with the four light beam spots 30a to 30d.
[0032]
Furthermore, as shown in FIG. 13, a case of a light source device using a laser diode array 102 in which three light emitting points 102a, 102b, and 102c are arranged on the outer edge at equal intervals of 120 ° will be described. The light emitting points 102a to 102c are arranged on a circumference Q centered on the optical axis C, and the line connecting the light emitting point 102a and the optical axis C is set to 60 ° with respect to the main scanning direction. As a result, the light emitting points 102a to 102c are apparently arranged at equal intervals in the sub-scanning direction. As shown in FIG. 14, the light beams B ₁ , B ₂ , and B ₃ emitted from the light emitting points 102a, 102b, and 102c are light beam spots 103a and 103b on the photosensitive drum 25 at equal intervals in the sub-scanning direction. , 103c. That is, the intervals between the spots 103a to 103c are “1” when the light beam interval p required from a desired image density is set to “1” units. Then, the light beam spots 103a to 103c are scanned in order from the front end side of the image while simultaneously writing three lines by one scanning, whereby an image is formed on the photosensitive drum 25.
[0033]
Furthermore, as shown in FIG. 15, a case of a light source device using a laser diode array 105 in which eight light emitting points 105a to 105h are arranged on a circumference Q centered on the optical axis C will be described. The light emitting points 105a to 105h are arranged on the outer edge portion at unequal intervals. Thus, the light emitting points 105a to 105h are apparently arranged at equal intervals in the sub-scanning direction. As shown in FIG. 16, the light beams emitted from the light emitting points 105a to 105h form light beam spots 106a to 106h on the photosensitive drum 25 at equal intervals in the sub-scanning direction. An image is formed on the photosensitive drum 25 by sequentially scanning from the leading end side of the image while simultaneously writing 8 lines by one scanning with the light beam spots 106a to 106h.
[0034]
The light source device and the light beam scanning optical device according to the present invention are not limited to the above-described embodiments, and can be variously modified within the scope of the gist.
As the light source, a light source having two-dimensionally arranged light emission points, a one-dimensionally arranged light source, a light source using an end surface light emitting element or a surface light emitting element, or the like is employed. Specifically, for example, as shown in FIG. 17, two end surface light emitting elements 401 and 402 are arranged in parallel, and the light emitting points 401a and 402a of the respective elements 401 and 402 are centered on the optical axis C. You may make it arrange | position on the circumference Q to do. Further, as shown in FIG. 18, the surface light emitting elements in which the light emitting points 405a are provided in a lattice shape are arranged so that four of the light emitting points 405a are located on a circumference Q centered on the optical axis C. May be.
[0035]
Further, as shown in FIG. 19, tandem light beam scanning in which, for example, cyan, magenta, yellow, and black photoconductors 503C, 503M, 503Y, and 503Bk are arranged in a row facing the transfer belt. The present invention is effectively applied to an optical apparatus. In FIG. 19, reference numeral 500 denotes a transfer belt.
Further, as shown in FIG. 20, a transfer drum 505, a photosensitive drum 506, and developing units 507C, 507M for cyan, magenta, yellow, and black arranged around the photosensitive drum 506, respectively. The present invention is also effectively applied to a light beam scanning optical apparatus of the type having 507Y and 507Bk.
[0036]
【The invention's effect】
As is clear from the above description, according to the present invention, each light beam emitted from the light emitting point is emitted from a position on a predetermined circumference approximately centered on the optical axis of the exit surface of the condenser lens, Since the aberrations of the light beams emitted from the condenser lens are substantially equal, a highly uniform image quality can be obtained. In addition, each light beam emitted from the light emitting point is emitted from a position on a predetermined circumference substantially centering on the optical axis of the exit surface of the condenser lens, and each light beam emitted from the condenser lens is an optical axis. For example, when the aperture is arranged on the optical axis at the back focal position of the condenser lens and the diameter of each light beam is regulated, all the light beams are equally divided by the aperture. This results in vignetting and a highly uniform image is obtained.
[0037]
Further, according to the present invention, the light emitting point is arranged on a circumference having a predetermined radius, and the condenser lens has a substantially axisymmetric shape with respect to a straight line passing through the center of the light emitting point of the light source. Therefore, the position of each light emitting point is optically equivalent to the condensing lens, and variation in the condensing state between the light beams can be suppressed. Then, by arranging the light emitting points of the light source at equal intervals on the circumference, the positional relationship between the light emitting points becomes equivalent, and variation in temperature rise between the light emitting points can be suppressed. As a result, it is possible to reduce variations in the amount of light between the light beams emitted from the light emitting points 2a to 2d.
[0038]
In addition, it further includes means for rearranging the order in the sub-scanning direction of the image data to be transmitted to the light emission point in accordance with the rotation of the light source by the means for rotating the light source. The apparent density can be changed, and the density of the image formed on the surface to be scanned can be switched.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an embodiment of a light beam scanning optical apparatus according to the present invention.
2 is an explanatory diagram showing a first example of the arrangement of light emitting points of the laser diode array shown in FIG. 1. FIG.
FIG. 3 is an explanatory diagram for regulating the diameter of a light beam.
4 is an explanatory diagram showing a light beam spot position on a scanned surface of a light beam emitted from a light emitting point shown in FIG. 2;
FIG. 5 is a drive timing chart of each light emitting point of the laser diode array.
6 is an explanatory diagram showing scanning by the light beam spot shown in FIG. 4. FIG.
FIG. 7 is an explanatory diagram showing image data transmitted to each light emitting point of a laser diode array.
FIG. 8 is a block diagram of a laser diode array drive circuit.
9 is an explanatory diagram showing a second example of the arrangement of the light emitting points of the laser diode array shown in FIG. 1. FIG.
10 is an explanatory view showing a light beam spot position on a surface to be scanned of a light beam emitted from the light emitting point shown in FIG. 9;
11 is an explanatory diagram showing scanning by the light beam spot shown in FIG. 9;
FIG. 12 is an explanatory diagram showing image data transmitted to each light emitting point of the laser diode array.
FIG. 13 is an explanatory diagram showing the arrangement of light emitting points of another laser diode array.
14 is an explanatory diagram showing scanning by the laser diode array shown in FIG. 13;
FIG. 15 is an explanatory diagram showing the arrangement of light emitting points of still another laser diode array.
16 is an explanatory diagram showing scanning by the laser diode array shown in FIG.
FIG. 17 is a front view showing another type of light source.
FIG. 18 is a front view showing still another type of light source.
FIG. 19 is a schematic configuration diagram showing another type of light beam scanning optical apparatus according to the present invention.
FIG. 20 is a schematic configuration diagram showing still another type of light beam scanning optical apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Light source unit 2 ... Laser diode array 2a, 2b, 2c, 2d ... Light emission point 5 ... Collimator lens 12 ... Polygon mirror 13, 14, 15 ... Scan lens 21 ... Rack 22 ... Pinion 23 ... Stepping motor 25 ... Photoconductor drum 30a, 30b, 30c, 30d ... light beam spots 102, 105 ... laser diode arrays 102a-102c, 105a-105h ... light emitting points 103a-103c, 106a-106h ... light beam spots 40 ... host computer 41 ... RAM
42: Controllers B ₁ , B ₂ , B ₃ , B ₄ ... Light beams

Claims (5)

A light source having three or more light emitting points, a condensing lens for shaping a light beam emitted from the light emitting points into either substantially parallel light or convergent light, and rotating the light source about an optical axis Each light beam emitted from the light emitting point is emitted from a position on a predetermined circumference substantially centered on the optical axis of the exit surface of the condenser lens, and from the condenser lens A light source device in which the aberration of each emitted light beam is substantially equal ;
A deflector that deflects and scans the light beam emitted from the light source device;
A scanning optical element that scans the light beam emitted from the deflector in a line on the surface to be scanned;
Means for rearranging the order in the sub-scanning direction of the image data transmitted to the light emitting point in accordance with the rotation of the light source by the means for rotating the light source;
A light beam scanning optical apparatus comprising: A light source having three or more light emitting points, a condensing lens for shaping a light beam emitted from the light emitting points into either substantially parallel light or convergent light, and rotating the light source about an optical axis Each light beam emitted from the light emitting point is emitted from a position on a predetermined circumference substantially centered on the optical axis of the exit surface of the condenser lens, and from the condenser lens A light source device in which each emitted light beam has substantially the same emission angle with respect to the optical axis ;
A deflector that deflects and scans the light beam emitted from the light source device;
A scanning optical element that scans the light beam emitted from the deflector in a line on the surface to be scanned;
Means for rearranging the order in the sub-scanning direction of the image data transmitted to the light emitting point in accordance with the rotation of the light source by the means for rotating the light source;
A light beam scanning optical apparatus comprising: A light source having three or more light emitting points, the light emitting point being arranged on a circumference having a predetermined radius, and a substantially axisymmetric shape with respect to a straight line passing through the center of the light emitting point of the light source; A light source device comprising: a condenser lens that shapes the light beam emitted from the light emitting point into either substantially parallel light or convergent light; and means for rotating the light source about an optical axis ;
A deflector that deflects and scans the light beam emitted from the light source device;
A scanning optical element that scans the light beam emitted from the deflector in a line on the surface to be scanned;
Means for rearranging the order in the sub-scanning direction of the image data transmitted to the light emitting point in accordance with the rotation of the light source by the means for rotating the light source;
A light beam scanning optical apparatus comprising: 4. The light beam scanning optical apparatus according to claim 3, wherein the light emitting points of the light source are arranged at equal intervals on the circumference. A plurality of light beams emitted from the light source device, according to any one of claims 1 to 3, characterized in that it is simultaneously scanned at intervals of integer ratio on the surface to be scanned in the sub-scanning direction Optical beam scanning optical device.

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