JPH0784202A - Optical scanning device - Google Patents

Abstract

(57) [Summary] [Object] To realize an optical scanning device capable of easily adjusting and changing the light spot diameter and keeping the optical energy of optical scanning constant regardless of the change of the light spot diameter. A laser light flux from a light source device 10 is converged by a cylinder lens system 12 in a sub-scanning corresponding direction to form a long line image LI in the main scanning corresponding direction, and a deflection reflection surface is formed in the vicinity of an image forming position of the line image LI. In the optical scanning device for performing optical scanning by converging the light beam deflected by the optical deflector 16 having 16A as a light spot on the surface to be scanned by the scanning imaging optical system 18, the light beam regulation amount by the aperture diaphragms 110 and 140 is changed. By doing so, the light spot diameter is changed. At that time, the laser output of the light source device 10 is changed so as to correct the change in light energy due to the change in the diameter of the light spot.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning device.

[0002]

2. Description of the Related Art A laser beam from a light source device using a laser light source as a light source is reflected by a deflecting / reflecting surface to be a deflected beam, which is focused as a light spot on a surface to be scanned by a scanning imaging optical system to perform optical scanning. The optical scanning method used is widely known in relation to optical printers and the like.

In order to realize high-precision optical scanning such as high-density recording, the "light spot diameter" must be stable at a predetermined size. The light spot diameter is determined by the optical element provided on the optical path from the light source to the surface to be scanned, and each optical element is designed and arranged so as to realize a desired light spot diameter. Since processing errors and assembly errors are unavoidable, and these errors also affect the light spot diameter, a means for adjusting the light spot diameter is required to obtain the light spot diameter as designed.

Further, an optical scanning device capable of switching the optical scanning density in a plurality of steps is also intended, and such switching of the optical scanning density can also be realized by switching the light spot diameter using the adjusting means. . Conventionally, a zoom optical system has been proposed as an adjusting means (Japanese Patent Laid-Open No. 1962/1990).
09), the cost is high as an adjusting mechanism,
Practicality is poor.

The optical deflector having a deflecting / reflecting surface is a rotary polygon mirror, a galvanometer mirror, a rotating two-sided mirror, a rotating single-sided mirror, or the like. The main scanning line fluctuates in the sub scanning direction, and an image abnormality called "jitter" occurs in the written image.

In order to correct the influence of such "surface tilt", the laser beam is expanded linearly along the optical axis in the sub-scanning corresponding direction (the optical path from the light source to the surface to be scanned) by the cylinder lens system. A direction parallel to the sub-scanning direction on the virtual optical path, and a direction parallel to the main scanning direction on the virtual optical path is referred to as a main scanning corresponding direction. At the same time, a long "line image" is formed in the vicinity of the deflecting / reflecting surface in the main scanning corresponding direction, and the scanning / imaging optical system sets the deflecting / reflecting surface position and the scanned surface position in the "geometrical optical" direction in the sub-scanning corresponding direction. Is a conjugate relationship with.

When the optical scanning device is constructed in this way, the scanning and imaging optical system inevitably becomes an "anamorphic" optical system in which the powers in the main scanning-corresponding direction and the sub-scanning corresponding direction are different from each other. It is difficult to satisfactorily correct the curvature of field of the image at the same time. When the scanning and imaging optical system has a field curvature, the light spot diameter varies with the image height of the light spot, so that it is difficult to realize precise high-density optical scanning. The fluctuation of the light spot diameter in the main scanning direction can be corrected by an electric operation of the writing signal, but the fluctuation of the light spot diameter in the sub scanning direction cannot be corrected by such a method.

Conventionally, as a method for correcting the fluctuation of the light spot diameter in the sub-scanning direction, a "cylinder lens system for forming a parallel laser beam from a laser light source into a long line image in the main scanning-corresponding direction" is used for the sub-scanning corresponding direction. A method of displacing in the optical axis direction according to the curvature of field is known (Japanese Patent Laid-Open No. Hei 4-
50193). However, in this method, since the mass of the cylinder lens is not necessarily small, it is not easy to move the cylinder lens at high speed in high-speed optical scanning.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and it is possible to easily and surely adjust / switch the light spot diameter with a simple structure and to prevent the fluctuation of the light spot diameter depending on the image height. It can surely reduce or prevent even high-speed optical scanning, and even if the light spot diameter is changed,
An object of the present invention is to provide a novel optical scanning device capable of effectively correcting a change in light energy due to a change in light spot diameter.

[0010]

An optical scanning device according to the present invention comprises a light source device, a line image forming element, an optical deflector, a scanning image forming optical system, an aperture stop, an aperture changing means, and a light source. And control means. The "light source device" uses a laser light source as a light source, and is a "variable laser output" device. As the laser light source, for example, a semiconductor laser can be used, but a gas laser solid laser can also be used as long as the laser output can be adjusted.
The laser light flux emitted from the light source device may be a parallel light flux, or may be a convergent light flux or a divergent light flux.

The "line image forming element" is an optical element which converges the laser beam from the light source device in the sub-scanning corresponding direction and forms a long line image in the main scanning corresponding direction. One or more optical elements are formed. A cylinder lens can be used suitably.

The "optical deflector" has a deflecting / reflecting surface near the image forming position of the line image formed by the line image forming element, and deflects the reflected light beam. As the optical deflector, a rotating polygon mirror, a galvano mirror, a rotating single-sided mirror or a rotating two-sided mirror can be used.

The "scanning and imaging optical system" is an optical system for converging the light beam deflected by the optical deflector as a light spot on the surface to be scanned. Therefore, the scanning and imaging optical system has a geometrical-optical conjugate relationship between the deflective reflection surface position (image forming position of the line image) and the scanned surface position in the sub-scanning corresponding direction. The scanning imaging optical system has a function of making the main scanning uniform in the main scanning corresponding direction. That is, when the optical deflector is a galvanometer mirror, the scanning and imaging optical system can be an f.sin.theta. Lens, and when the optical deflector is a rotating polygon mirror, a rotating two-sided mirror, or a rotating single-sided mirror, a scanning connection is possible. The image optical system can be a “fθ lens”.

The "aperture stop" is provided between the light source device and the optical deflector, and regulates the laser beam in at least the sub-scanning corresponding direction. The "aperture changing means" is a means for changing the light flux regulation amount by the aperture stop. The “light source control unit” is a unit that controls the laser output in the light source device so as to correct the change in the light amount of the optical scanning due to the change in the light beam regulation amount in accordance with the change in the light beam regulation amount of the aperture stop by the aperture changing unit.

The change in the light flux regulation amount by the aperture varying means is
It may be performed for "light spot diameter adjustment" (Claim 2), "switching of optical scanning density" (Claim 3), and "field curvature of scanning imaging optical system". It is also possible to correct the fluctuation of the light spot diameter due to “. Further, these “adjustment of light spot diameter”, “switching of light scanning density” and “correction of light spot diameter variation due to field curvature” may be combined with each other.

The optical scanning device according to any one of claims 1 to 4 is, as in the conventional optical scanning device, "deflected by an optical deflector,
Detects the deflected light flux toward the scanning start position on the surface to be scanned,
It is possible to have a "optical sensor means for generating a synchronization signal for starting optical scanning", but to set a reference value for laser output control in the light source device based on the light intensity of the deflected luminous flux detected by the optical sensor means. (Claim 5) In this case, the optical sensor means may have a photosensor as the light receiving means, and may have a convex lens and / or a concave lens having a power in at least the main scanning corresponding direction in front of the photosensor.

In the optical scanning device according to any one of claims 1 to 6, the "aperture stop" has a main-scanning-direction aperture stop that regulates the laser light flux in the main-scanning corresponding direction, and a laser light-flux regulation in the sub-scanning corresponding direction. The sub-scanning corresponding direction aperture stops may be provided separately from each other (claim 7).

[0018]

As will be described later, in the case of converging a laser beam, the so-called beam waist size is inversely proportional to the beam diameter of the converged laser beam. Therefore, the laser light beam is regulated in the main scanning corresponding direction and / or the sub scanning corresponding direction by the aperture stop, and the light beam regulation amount is changed, so that the light spot diameter on the surface to be scanned is changed in the main scanning direction and / or the sub scanning direction. It can be changed in the scanning direction.

At this time, if the intensity of the laser light beam emitted from the laser light source is constant, the light energy reaching the surface to be scanned changes when the light beam regulation amount is changed.

Therefore, according to the present invention, the laser output in the light source device is changed by the light source control means in accordance with the change in the light flux regulation amount by the aperture stop, and the change in the light energy is corrected.

[0021]

EXAMPLES Specific examples will be described below. Figure 1
(A) schematically shows only an essential part of one embodiment of the optical scanning device according to claims 1, 3, 4, 5, 6, and 7. The “light source device” shown by reference numeral 10 is composed of a semiconductor laser and a coupling lens for converting a divergent light beam from this semiconductor laser into a parallel light beam, and emits a parallel laser light beam.

The parallel light beam emitted from the light source device 10 is condensed only in the sub-scanning corresponding direction by the cylinder lens 12 as a "line image forming element", and is deflected and reflected by the rotary polygon mirror 16 which is an "optical deflector". A long line image LI is formed at the position of the surface 16A in the main scanning corresponding direction. The light beam reflected by the deflecting / reflecting surface 16A becomes a periodic “deflecting light beam” as the rotary polygon mirror 16 rotates in the direction of the arrow, and enters the fθ lens 18 which is a “scanning image forming optical system”. By the action, the light is condensed as a light spot on the photoconductor 20,
Scan at a constant speed. In the figure, the symbol L indicates the movement locus of the light spot, that is, the "main scanning line". The tangential plane of the photoconductor 20 including the main scanning line L is the “scanned surface”.

A first aperture means 110, which is an "aperture stop corresponding to the main scanning direction", is provided between the light source device 10 and the cylinder lens 12, and between the cylinder lens 12 and the rotary polygon mirror 16. A second aperture means 140, which is an "aperture stop corresponding to the sub-scanning direction", is provided to cut off the peripheral light flux portion of the laser light flux in the main / sub-scanning corresponding directions.

The first aperture means 110 comprises strip type light shielding plates 111 and 112 arranged in parallel to the sub-scanning corresponding direction, and the distance between the two can be adjusted by an adjusting mechanism 24. The second aperture means is a strip type light shield plate 14.
1, 142 are arranged parallel to the main scanning corresponding direction, and the distance between the two can be adjusted by the adjusting mechanism 23.

The first and second aperture means 110 and 140 which are separate from each other constitute an "aperture stop". Further, the adjusting mechanisms 23 and 24 and the control means for controlling them constitute "aperture changing means". Adjustment mechanism 2
As the elements 3 and 24, a known appropriate parallel movement mechanism can be used.

FIG. 1B shows the "optical path between the cylinder lens 12 and the deflecting / reflecting surface 16A" in the optical arrangement shown in FIG.
Is drawn such that the sub-scanning corresponding direction is the vertical direction. Light-shielding plates 141, 1 of the second aperture means 140
When 42 is in the position shown by the solid line in the figure, the laser light flux is directed in the sub-scanning corresponding direction before entering the cylinder lens 12 for the optical system arranged on the deflective reflection surface 16A side of the second aperture means 140. Diameter: It will have 2ω _0S .

At this time, the light beam diameter in the sub-scanning corresponding direction at the line image position (the position of the deflecting reflection surface 16A) imaged by the cylinder lens 12: 2ω _1S is the focal length of the cylinder lens 12 in the sub-scanning corresponding direction: f _cy and the wavelength of the laser beam: λ are given by 2ω _1S = 4K · λ · f _cy / (π · 2ω _0S ). K is a constant. When the light spot diameter on the surface to be scanned in the sub-scanning corresponding direction is 2ω _2S ,
This light spot diameter: 2ω _2S is 2ω _2S = β · 2ω _1S = 4K · β · λ · f _cy / (π · 2ω, where β is the lateral magnification of the fθ lens 18 in the sub-scanning corresponding direction.
_0S ). That is, the optical spot diameter in the sub-scanning corresponding direction on the scanned surface: 2 [omega _2S is beam diameter: because there in 2 [omega _0S inversely proportional relationship, beam diameter: 2 [omega _0S by adjusting the light in the sub-scanning corresponding direction Spot diameter: 2ω _2S
Can be changed.

As shown in FIG. 1B, when the positions of the light shielding plates 141, 142 of the first aperture means 140 are displaced to the positions indicated by the broken lines, the luminous flux diameter: 2ω _0S is the luminous flux diameter indicated by the chain line: 2ω _0S. 'changes, the beam diameter on the deflection reflective surface 16A from 2 [omega _1S 2 [omega _1S' changes to. Therefore, if the light flux regulation amount by the first aperture means 140 is reduced,
The light spot diameter: 2ω _2S can be changed so as to be small, and the light spot diameter on the surface to be scanned in the sub-scanning direction can be made small.

FIG. 1C shows a state in which the deflected light beam in the main scanning corresponding direction (substantially parallel light beam in the main scanning corresponding direction) is condensed on the surface to be scanned by the fθ lens 18 which is an optical system. Is shown. At this time, fθ lens 1
8 has a diameter of 2ω in the main scanning corresponding direction
_0M (light-shielding plates 111, 112 of the first aperture means 110)
Is the position of the solid line), the diameter of the light spot on the surface to be scanned in the main scanning direction: 2ω _M is the focal length of the fθ lens 18 in the main scanning corresponding direction: f, the wavelength of the laser beam: λ _Is given by 2ω _M = 4K · λ · f / (π · 2ω _0M ). Further, if the light-shielding plates 111 and 112 are moved to the positions indicated by the broken lines to widen the aperture width, the diameter of the laser beam in the main scanning corresponding direction increases to 2ω _0M 'and the diameter of the light spot in the manual scanning direction increases. It becomes as small as 2ω _M '.

Thus, the first and second aperture means 1
The light spot diameter can be changed by changing the aperture width by 10, 140 and changing the light flux regulation amount.

In the case where the light spot diameter fluctuates according to the image height in both the main and sub scanning directions due to the field curvature of the fθ lens 18, the fluctuation of the light spot diameter in the main scanning direction and the sub scanning direction due to the image height is reduced or reduced. To remove, at the image height position where the light spot diameter becomes large, the light flux diameter of the laser light flux: 2
omega _0S, as 2 [omega _0M increases, also 2 [omega optical spot diameter in the smaller image height position _0S, as 2 [omega _0M decreases, first, by controlling the opening width of the second aperture means 110, 140 good. In this case, the adjusting mechanism 23, 24
Since the adjusting operation by means is extremely fast, a voice coil, a piezoelectric element or the like that can be driven at high speed is used.

First and second aperture means 110,1
When the aperture width of 40 is fixed to a fixed value, the change of the light spot diameter in the main / sub scanning direction due to the curvature of field of the fθ lens 18 is expressed as a function of the image height: H, 2ω _M (H), 2ω _2S (H )
Then, these are uniquely determined according to the field curvature.

Therefore, depending on the image height: H, 2ω _M (H), 2
At the image height position where ω _2S (H) becomes large, the luminous flux diameter: 2
ω _0S , 2ω _0M becomes large, and 2ω _M (H), 2ω
_{At the} image height position where _2S (H) becomes small, 2ω _0S and 2ω _0M become small, so that the first and second aperture means 110, 1
By controlling the opening width of 40, 2ω _M (H) and ω _2S (H) can be controlled to be constant or substantially constant regardless of the field curvature.

For this purpose, the aperture width of the first and second aperture means is a function of the image height: H (a specific set of aperture widths corresponding to the image height: H and 1: 1 or a set of the aperture widths). It is stored in the control means 25 as a set (approximated by an analytic function).

At the time of optical scanning, the deflected light flux toward the optical scanning section is detected by the photosensor 26 shown in FIG. 2A, and the writing timing of each pixel of the optical scanning by the clock phase-synchronized with the output of the photosensor 26 ( Pixel clock) is determined.

Since the pixel clock corresponds to the image height: H of the light spot, the control means 25 controls the aperture width of the first aperture means 110 according to the image height: H corresponding to the pixel clock to the adjusting mechanism 24 and the image. High: The aperture width of the second aperture means 140 according to H is output to the adjusting mechanism 23,
The adjusting mechanisms 24 and 23 realize the opening widths of the first and second aperture means according to the signal from the control means 25. Thus, the optical scanning can be executed while keeping the light spot diameter in the main / sub-scanning corresponding direction constant or substantially constant.

As described above, the light spot diameter is constant or substantially constant, but since the light flux regulation amount is changed in order to keep the light spot diameter constant, the laser output of the light source device is constant. Then, the light energy reaching the surface to be scanned changes according to the image height of the light spot.

Therefore, according to the present invention, the laser output in the light source device is controlled so as to correct the fluctuation of the light energy according to the change of the light flux regulation amount. Since the light flux regulation amount is uniquely determined by the aperture width in the first and second aperture means, basically, the relationship between the aperture width and the laser output is determined so that the light energy is constant, and for example, control is performed. The light amount correction circuit 29 may be controlled by the control signal from the means to change the laser output in the light source device 10.

By the way, as in the invention described in claim 3,
When switching the optical scanning density by switching the light spot diameter, the first and second aperture means 110,
The reference width of the opening width of 140 differs depending on the optical scanning density, and the opening width is controlled based on the reference width set according to the optical scanning density.

In such a case, the setting of the reference laser output according to the optical scanning density in the light source device 10 is
This is done as follows.

The reference laser output in the light source device is
It is determined according to a reference optical scanning density (for example, 400 dpi), and when the optical scanning device is operated,
The laser output is always set to the above standard.

When the optical scanning density is switched to, for example, 200 dpi, the light spot diameter becomes large. Accordingly, the opening width of the first and second aperture means 110, 140 is smaller than that when the reference width is 400 dpi. Once set, the luminous flux regulation amount increases accordingly. Therefore, it is necessary to increase the light energy.

For this purpose, the reference value is set according to the optical scanning density of the laser output as follows. The output of the photo sensor 26 for synchronizing the optical scanning start is shown in FIG.
As shown in (a). That is, when the deflected light flux crosses the light receiving surface of the photosensor 26, the output: P gradually increases from when the deflected light flux starts to enter the light receiving surface, and when the deflected light flux deviates from the light receiving surface, the output: P becomes maximum. . That is, the output: P proportionally corresponds to the integrated value of the amount of light received by the light receiving surface when the deflected light flux passes through the light receiving surface. When this output: P is differentiated by the differentiating circuit 27 shown in FIG. 1A, the output: dP / dt of the differentiating circuit 27 becomes a mountain-shaped signal as shown in FIG. 2B. The peak value: Pt of this mountain-shaped signal has a "correspondence relation" proportional to the laser output of the light source device 10. Therefore, this peak value: Pt is detected by the peak hold in the light quantity recognition circuit 29, and the correspondence relation is obtained. The laser output in the light source device 10 is detected, and the laser output in the light source device 10 is corrected by the light amount correction circuit 31 based on the result, and the reference value of the light energy reaching the scanned surface regardless of the switching of the optical scanning density. Is to be constant.

As shown in FIG. 1A, a cylinder lens 261 is provided in front of the photo sensor 26. The cylinder lens 261 can move in and out of the optical path between the photosensor 26 and the deflection origin of the deflected light beam by the rotary polygon mirror 16.

As described above, in this embodiment, the laser output of the light source device is set on the basis of the optical scanning density of 400 dpi, and when the optical scanning density is switched to 200 dpi, the aperture stop is narrowed down. The amount of light detected by the sensor 26 also decreases. Moreover, when the optical scanning density is set to 200 dpi, the light flux is deflected at a high speed, and the time for the deflected light flux to cross the light receiving surface of the photosensor 26 is shortened.

Therefore, when the optical scanning density is switched to 200 dpi, the output P of the photosensor 26 becomes small, and the peak value Pt in the output of the differentiating circuit 27 also becomes small, so that the laser output of the light source device 10 can be detected. It may cause an error.

Therefore, in this embodiment, when the optical scanning density is switched to 200 dpi, a cylinder lens 261 having a positive power in the main scanning corresponding direction is arranged in front of the photo sensor 26, as shown in FIG. As shown in
While the deflected light flux DF crosses the lens surface of the cylinder lens 261, the light is made incident on the photo sensor 26 so that the output of the photo sensor 26 is increased and the laser output can be accurately detected.

Contrary to the above, it is also possible to set the reference of the laser output according to the optical scanning density of 200 dpi. In that case, when the light scanning density is switched to 400 dpi, the amount of light received by the photo sensor 26 is
In such a case, the output of the photo sensor 26 may be saturated before the deflected light flux has crossed the light receiving surface of the photo sensor 26 and is too large with respect to the light receiving ability of the photo sensor 26. Therefore, it becomes difficult to adjust the laser output at 400 dpi. In such a case, as shown in FIG. 2D, the cylinder lens 262 having a negative power in the main scanning corresponding direction is attached to the photo sensor 26.
It is sufficient that the deflected light flux DF is provided in front of the photo sensor 26 to reduce the amount of light incident on the photo sensor 26.

The case where the laser output of the light source device 10 is changed according to the field curvature of the fθ lens 18 in the main and sub-scanning directions has been described above. Since it can be corrected by electrically changing the signal, the correction of the light spot variation according to the field curvature may be performed only for the light spot diameter in the sub-scanning direction. In this case, the adjustment of the light flux regulation amount by the first aperture means 110 only needs to be performed for switching the optical scanning density and / or adjusting the deviation of the light spot diameter from the design value.

In addition, of course, neither the main scanning direction nor the sub-scanning direction is adjusted for the variation of the light spot diameter due to the field curvature, and the first and second aperture means 110, 1 constituting the aperture stop.
The light amount regulation amount change by 40 may be performed exclusively for switching the optical scanning density and / or adjusting the deviation of the light spot diameter from the design value. In this case, the first and second aperture means 110, 140 may adjustively change the aperture width or switch the aperture width according to the optical scanning density. In any case, to adjust the laser output according to the change in aperture width,
This can be performed by the method described with reference to FIGS.

The aperture stop is not limited to the first and second aperture means 110 and 140 as described above, but as shown in FIG. 3, the first aperture means 110 regulates the luminous flux in the main scanning corresponding direction and corresponds to the sub scanning. The direction of the light flux is regulated by moving the aperture plate 14 having an opening having a predetermined opening width in the sub-scanning corresponding direction by the moving mechanism 222 to the cylinder lens 12.
It may be performed by moving it in the optical axis direction. In the sub-scanning corresponding direction, the laser light flux has a tendency to converge between the cylinder lens 12 and the deflective reflection surface 16A. Therefore, the light flux regulation amount can be changed by displacing the aperture plate 14 as described above. You can

When the laser beam emitted from the light source device is converging or diverging, the aperture plate also regulates the light beam in the main scanning corresponding direction, and this aperture plate is used as the optical axis of the cylinder lens 12. By displacing in the direction, the light flux regulation amount can be changed.

As described above, since the light spot diameter in the main scanning direction can be electrically corrected, the light flux regulation in the main scanning corresponding direction by the aperture stop may be omitted. For example, the first aperture means 110 in FIGS. 1A and 3 can be omitted.

[0054]

As described above, according to the present invention, a novel optical scanning device can be provided. Since the present invention is configured as described above, it is possible to correct an error from the design value of the light spot diameter in the optical scanning device, to adjust the switching of the light spot diameter in accordance with the switching of the optical scanning density, or the scanning imaging optical system. It is possible to easily and surely correct the fluctuation of the light spot diameter due to the curvature of field, and at that time, it is possible to surely correct the change of the optical energy of the optical scanning due to the change of the light spot diameter.

Further, in the inventions described in claims 5 to 6, it is easy to adjust the laser output in order to correct the change in the light change energy, and in the invention described in claim 7, the regulation of the luminous flux of the laser beam is mainly performed.・ It can be performed independently in the sub-scanning compatible direction.

Since the movable portion of the aperture stop is light in weight for correcting the light spot diameter, it is possible to move the light beam, and it is possible to sufficiently cope with high-speed optical scanning when correcting the light spot diameter due to field curvature. is there.

[Brief description of drawings]

FIG. 1 is an embodiment of the invention according to claims 1, 3, 4, 5, 6, and 7.
It is a figure for explaining an example.

FIG. 2 is a diagram for explaining detection of laser output in the above embodiment.

FIG. 3 is a diagram schematically showing another embodiment.

[Explanation of symbols]

10 Light Source Device 12 Cylinder Lens (Line Image Forming Element) 110 First Aperture Means 140 Second Aperture Means (Composes an Aperture Stop with the First Aperture Means) 16 Optical Deflector 18 Scanning Imaging Optical System

Claims (7)

[Claims] 1. A light source device having a variable laser output, a line image forming element for converging a laser beam from the light source device in a sub-scanning corresponding direction and forming a long line image in the main scanning corresponding direction, and the line. An optical deflector having a deflecting / reflecting surface in the vicinity of an image forming position, a scanning imaging optical system for converging a light beam deflected by the optical deflector as a light spot on a surface to be scanned, the light source device and the optical deflector. An aperture stop for restricting the laser light flux in at least the sub-scanning corresponding direction, an aperture variable means for changing the light flux regulation amount by the aperture diaphragm, and a light flux regulation amount change of the aperture diaphragm by the aperture variable means. Accordingly, the optical scanning device is provided with a light source control means for controlling the laser output in the light source device so as to correct the change in the light amount of the optical scanning due to the change in the light flux regulation amount. 2. The optical scanning device according to claim 1, wherein the light beam regulation amount is changed by the aperture changing means for adjusting the light spot diameter. 3. The optical scanning device according to claim 1 or 2, wherein the light beam regulation amount is changed by the aperture changing means for switching the optical scanning density. 4. The optical scanning device according to claim 1, 2 or 3, for correcting a change in the light amount regulation amount by the aperture changing means and for correcting a change in the light spot diameter due to the field curvature of the scanning image forming optical system. An optical scanning device characterized by performing. 5. The optical scanning device according to claim 1, 2 or 3 or 4, wherein a deflected light beam deflected by an optical deflector and traveling toward a scanning start position on a surface to be scanned is detected, and synchronization for starting optical scanning is detected. An optical scanning device comprising an optical sensor means for generating a signal, and setting a reference value for laser output control in a light source device based on the light intensity of a deflected light beam detected by the optical sensor means. 6. The optical scanning device according to claim 5, wherein the optical sensor means has a photosensor as a light receiving means, and has a convex lens and / or a concave lens in front of the photosensor and having power in at least the main scanning corresponding direction. An optical scanning device comprising: 7. The optical scanning device according to claim 1, 2 or 3 or 4 or 5 or 6, wherein the aperture stop is a main scanning corresponding direction aperture stop which regulates a laser beam in the main scanning corresponding direction, and a sub scanning corresponding. An optical scanning device, characterized in that sub-scanning-direction aperture stops that regulate the direction of laser light flux are provided separately from each other.