JP3434153B2 - Optical scanning device - Google Patents

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 used as an image writing means in an image forming apparatus such as a laser printer, a digital copying machine, a laser facsimile.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a laser printer, a digital copying machine, a laser facsimile, etc., as a means for writing an image on a photoconductor or the like, a laser beam is made into a minute light spot on a surface to be scanned on the photoconductor or the like. An optical scanning device is used that writes an image (electrostatic latent image) by forming an image on a laser beam, scanning the light spot in the main scanning direction, and intensity-modulating according to an image signal.
For example, a substantially parallel light flux from a laser light source such as a semiconductor laser is guided to an optical deflector such as a rotating polygon mirror through an optical system such as a cylindrical lens, and the light deflector deflects the light flux to form a deflected light flux. There is a configuration in which an image is formed on the surface to be scanned by an image optical system.

In such an optical scanning device, it is possible to change the density of the writing laser light at the image forming position without changing the utilization efficiency of the light of the laser light source, and to set the writing time. There has been proposed a device provided with a means capable of adjusting a writing operation to a condition set by a user (see Japanese Patent Laid-Open No. 4-194813). And, in the technique described in the above publication, as a means for making it possible to select the density of the writing laser beam,
As shown in 1 to 4 below, a means for switching the spot diameter of the light spot in the sub-scanning direction is provided. 1. The means for switching the spot diameter in the sub-scanning direction has a structure in which the cylindrical lens is replaced. 2. The means for switching the spot diameter in the sub-scanning direction has a structure in which the size of the aperture stop is changed to make the spot diameter in the main scanning direction different, and the emission output of the laser light source is changed in accordance with the change in the aperture stop. Switch. 3. The means for switching the spot diameter in the sub-scanning direction has a structure in which the size of the aperture stop is changed to make the spot diameter in the sub-scanning direction different, and the emission output of the laser light source is changed in accordance with the change in the aperture stop. Switch. 4. The means for switching the spot diameter in the sub-scanning direction has a structure in which the size of the aperture stop is changed so that the spot diameters in the main and sub-scanning directions are made different. Switch the light emission output of.

Further, an optical element such as a cylindrical lens can be attached to the case with a simple structure and with high accuracy, and the cylindrical portion of the cylindrical lens can be rotated as an optical scanning device for facilitating alignment of the generatrix and adjustment of the focus position. In addition, there has been proposed a device having a holding portion that holds it so as to be slidable in the optical axis direction (see Japanese Patent Laid-Open No. 4-178668).

[0005]

The print speed and resolution of laser printers and the like tend to increase year by year, and it is necessary to change the light quantity, the light spot diameter, etc. according to the print speed and resolution. Conventionally, the arrangement of the optical elements differs depending on the print speed and the resolution, so that it is necessary to design the optical housing each time.
Alternatively, a method of mechanically and electrically switching the arrangement of optical elements by using a slide mechanism or the like is used.

The above-mentioned Japanese Patent Laid-Open No. 4-194813 proposes means for arranging a plurality of cylindrical lenses in advance in order to switch the light spot diameter and providing a slide mechanism for selection. Moreover, a means for changing the aperture stop and changing the light emission output of the laser light source is proposed. On the other hand, when mounting a cylindrical lens or the like, there is a method of adjusting by attaching a rotation or slide mechanism as seen in JP-A-4-178668. However, in the optical scanning device,
Providing a movable part such as a slide mechanism and adjustment / change means has a problem that the number of parts increases and the difficulty of assembly increases, leading to an increase in cost.

The present invention has been made in view of the above circumstances. In the present invention, the optical system of the optical scanning device is provided with a plurality of holding mechanisms in advance, so that the optical scanning device can be used in common even if the print speed or resolution is changed. It is an object of the present invention to realize a low-cost optical scanning device which is mechanically and electrically advantageous because it can use the optical housing described above and does not have a movable part or adjustment / change means.

[0008]

In order to achieve the above object, in the invention described in claim 1, a light source section, a first optical system for guiding a light beam from the light source section to an optical deflector, and the light beam is scanned. An optical deflector for scanning, a second optical system for condensing the scanned light flux as a light spot on the surface to be scanned, a photodetector for generating a synchronization signal for determining the writing start position, and scanning. In the optical scanning device including the third optical system that guides the luminous flux to the photodetection unit, the holding mechanism of at least one optical element forming the first optical system, the second optical system, and the third optical system is A plurality of elements are arranged according to the mounting position of the element, and the plurality of holding mechanisms are independent
Then, it is arranged as a separate body .

According to a second aspect of the present invention, in addition to the structure of the first aspect, a plurality of holding mechanisms are all configured to have the same structure.

According to a third aspect of the present invention, in addition to the structure of the first aspect, a plurality of holding mechanisms are configured so that at least one of the holding mechanisms has a different structure.

According to a fourth aspect of the present invention, in addition to the configuration of the second or third aspect, a plurality of holding mechanisms are provided.
The optical systems are arranged side by side in the optical axis direction of each optical system.

According to a fifth aspect of the present invention, in addition to the configuration of the fourth aspect, a plurality of holding mechanisms is a holding mechanism for the optical element forming the first optical system.

According to a sixth aspect of the invention, in addition to the configuration of the fifth aspect, the first optical system has an aperture function, and the aperture diameter is determined according to the mounting position of the optical element.

According to the invention of claim 7, in addition to the structure of claim 5 or 6, a plurality of holding mechanisms are provided.
The holding mechanism of the cylindrical lens of the first optical system is configured to limit the light flux coupled from the light source unit by the aperture function and form a long and narrow line image in the vicinity of the deflecting reflection surface of the optical deflector.

According to an eighth aspect of the invention, in addition to the configuration of the sixth or seventh aspect, the aperture diameter is determined so as to change the light quantity while keeping the light spot diameter on the surface to be scanned constant. did.

According to a ninth aspect of the present invention, in addition to the configuration of the sixth or seventh aspect, the aperture diameter is determined so as to change the light spot diameter while keeping the amount of light on the surface to be scanned constant. did.

According to a tenth aspect of the invention, in addition to the configuration of the sixth or seventh aspect, the aperture diameter is determined so as to change the light quantity and the light spot diameter on the surface to be scanned.

According to an eleventh aspect of the invention, in addition to the configuration of the seventh aspect, a plurality of holding mechanisms are provided, and the first holding mechanism is different from the light source side.
The second holding mechanism and the third holding mechanism have the same configuration.

According to the twelfth aspect of the present invention, in addition to the configuration of the seventh aspect, a plurality of holding mechanisms are provided, and the first holding mechanism and the second holding mechanism are the same in order from the light source side. The third holding mechanism is different.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 4 is a schematic configuration diagram showing an example of an optical scanning device according to the present invention, which includes a light source 10, a light deflector 12, and first to third optical systems 11a, 11b, 13, 1.
5, an example of the arrangement of the components such as the photodetector 17 on the scanning plane is shown. The scanning plane is a plane parallel to the optical axis of the optical system and the scanning direction (main scanning direction) of the light beam by the optical deflector 12.

In FIG. 4, "semiconductor laser (LD)"
The divergent light beam emitted from the light source 10 is coupled by the coupling lens 11a and converged only by the cylindrical lens 11b in the scanning vertical direction (the direction perpendicular to the scanning plane, also referred to as the sub-scanning direction). , Is imaged as a "long line image in the scanning direction" in the vicinity of the deflective reflection surface 12a of the optical deflector 12. The coupling lens 11a and the cylindrical lens 11b constitute a "first optical system".

The light beam emitted from the first optical system may be a "parallel light beam", a "weakly divergent light beam" or a "weakly convergent light beam" in the scanning direction. The light deflector 12 rotates at a constant speed in the direction of the arrow in the figure, and the light beam reflected by the deflection reflection surface 12a becomes a deflected light beam, which is deflected clockwise at a constant angular velocity in FIG. This deflected light beam is incident on the second optical system 13 composed of a scanning imaging lens such as an fθ lens, and is formed as a minute light spot on the surface to be scanned 14 such as a photoconductor by the imaging action of the second optical system 13. Collect light. The light spot is
The surface 14 to be scanned is moved in the scanning direction to optically scan the surface 14 to be scanned. The second optical system 13 has a function of making the movement of the light spot on the scanned surface 14 uniform. Further, the line image formed by the cylindrical lens 11b of the first optical system is formed near the deflection reflection surface 12a of the optical deflector 12, and the second line image is formed.
The optical system 13 collects the deflected light flux as a light spot on the surface 14 to be scanned, so that the optical scanning device of FIG.
It has a function to correct the "troublesome" in. The second optical system 13 has a single-lens configuration in the embodiment shown in FIG. 4, but may have two or more lenses.

The light beam deflected by the optical deflector 12 is incident on the third optical system 15 prior to the optical scanning of the surface 14 to be scanned, and by the action of the third optical system 15, the light detecting section 17 by the "light receiving element". Is focused on. The photodetector 17 emits a detection signal when detecting the deflected light flux, and based on the detection signal, a synchronization signal for determining the "writing start position A" by optical scanning is issued.

In the following, a case where a plurality of holding mechanisms for the cylindrical lenses constituting the first optical system are arranged will be described as an example.

The following means are available as a method for improving the printing speed and resolution without changing the light output intensity (hereinafter referred to as LD power) of the semiconductor laser and the sensitivity of the photoconductor. Generally, when the printing speed is improved (the resolution is constant, that is, the light spot diameter is also constant), the rotation speed of the optical deflector 12 becomes faster, and the required light amount on the surface to be scanned 14 (on the photoconductor) becomes larger. That is, it is necessary to increase the LD power. But,
In order to secure the necessary amount of light without changing the LD power, move the cylindrical lens position closer to the light source side,
The aperture diameter is increased so that the numerical aperture (NA) of the light beam incident on the optical deflector is kept constant (the light spot diameter is kept constant). That is, FIG. 5 shows a sectional view of the main part of the optical scanning device in the sub-scanning direction. As shown in FIG. 5A, an opening (aperture) 11 is formed in front of the cylindrical lens 11b.
In order to improve the printing speed by providing c, the position of the cylindrical lens 11b is brought closer to the light source side as shown in FIG. 7B, and the numerical aperture (N) of the light beam incident on the deflection reflection surface 12a of the optical deflector (N ..A.) Is kept constant (the light spot diameter is constant) by increasing the aperture diameter of the aperture 11c (θ is equal, d <d '), and the required light amount is secured without changing the LD power. can do.

On the other hand, in general, in order to improve the resolution (print speed is constant), it is necessary to reduce the light spot diameter. For that purpose, the numerical aperture (NA) of the light beam incident on the optical deflector can be increased. Good. The means is
Keeping the aperture diameter constant (the amount of light on the scanned surface is constant)
Then, bring the cylindrical lens closer to the optical deflector side. That is, FIG. 6 is a cross-sectional view of the main part of the optical scanning device in the sub-scanning direction. As shown in FIG. 6A, when the aperture 11c is provided in front of the cylindrical lens 11b to improve the resolution, it is the same. The opening diameter d of the opening 11c as shown in FIG.
By keeping the position of the cylindrical lens 11b close to the deflection reflection surface 12a side of the optical deflector while keeping
The light spot diameter can be reduced (d is equal and θ <θ ′) while the amount of light on the surface to be scanned is constant.

In addition, the LD power and the sensitivity of the photosensitive member may be changed according to the print speed and resolution. In that case, it is necessary to change the required light amount and the light spot diameter on the photoconductor (scanned surface), and it is necessary to set the aperture diameter of the aperture and the cylindrical lens position to be optimum.

When the position of the cylindrical lens is changed, in order to form a "long line image in the scanning direction" near the deflection reflection surface of the optical deflector, the radius of curvature of the cylindrical lens changes depending on the position. Therefore, the cylindrical lens in each arrangement is different. In that case, it is needless to say that when the cylindrical lenses are made of the same material, it is optimal that they are made of the same outer shape, and it is desirable that the holding mechanisms have the same configuration (shape, constituent members, materials, etc.). Further, when the materials are made of different materials, that is, glass and plastic, the outer shape of the cylindrical lens may be different. Therefore, it is desirable to use a holding mechanism having a configuration (shape, constituent member, material, etc.) suitable for each.

[0029]

EXAMPLES Specific examples of the optical scanning device according to the present invention will be described below. FIG. 1 is a schematic configuration diagram of an optical scanning device showing an embodiment of the present invention. The basic configuration and operation are the same as those of the optical scanning device shown in FIG. 4, and those denoted by the same reference numerals have the same configuration. It is a member. In the optical scanning device shown in FIG. 1, the first optical system is composed of a coupling lens 11a, a cylindrical lens 11b, and an aperture (aperture) 11c. For the cylindrical lens 11b, there are three holdings depending on the mounting position. Mechanisms 18a, 18
b and 18c are arranged. These three holding mechanisms 18
a, 18b, 18c all have the same configuration (shape, component,
A holding mechanism made of a material, etc., which are arranged in parallel in the optical axis direction of the first optical system, and are arranged from the light source 10 side to the first holding mechanism 18a,
The second holding mechanism 18b and the third holding mechanism 18c are arranged in this order. Therefore, the cylindrical lens 11b is held by any one of the three holding mechanisms 18a, 18b, 18c in the optical axis direction depending on the print speed, resolution, and the like.

The opening diameter of the opening 11c of the first optical system is determined according to the mounting position of the cylindrical lens 11b. For example, when the print speed and resolution are normal, the cylindrical lens 11b is located at the center of the first lens. Although it is attached to the second holding mechanism 18b, the cylindrical lens 11b is attached to the first holding mechanism 18a on the light source side when the printing speed is improved (the resolution is constant, that is, the light spot diameter is also constant). The aperture diameter of the aperture 11c is determined so as to change the light amount while keeping the light spot diameter on 14 constant. That is, when the amount of light is increased, the aperture diameter is increased. Further, in order to improve the resolution (print speed is constant), the cylindrical lens 11b is attached to the third holding mechanism 18c on the optical deflector 12 side to keep the light amount on the surface 14 to be scanned constant and the light spot. The opening diameter of the opening 11c is determined so as to change the diameter. In this case, since the amount of light is constant, the aperture diameter is also constant. In addition, one of the three holding mechanisms 18a, 18b, and 18c is selected so that the position of the cylindrical lens 11b is optimum according to the print speed and the resolution, and accordingly, the light amount on the surface to be scanned 14 and The opening diameter of the opening 11c is determined so as to change the light spot diameter.

As described above, the cylindrical lens 11b
When changing the position of, the deflection reflection surface 1 of the optical deflector 12
In order to form a "long line image in the scanning direction" near 2a, the radius of curvature of the cylindrical lens 11b changes depending on the position, and the cylindrical lens 11b in each arrangement is different. At this time, when the cylindrical lens 11b is made of the same material, it is optimal that the cylindrical lens 11b is made of the same outer shape, so that the three holding mechanisms 18a,
18b and 18c may have the same configuration (shape, components, material, etc.). However, when they are made of different materials, that is, glass and plastic, the outer shapes may be different, so it is desirable to have a holding mechanism suitable for each, and at least one of the holding mechanisms arranged has a different configuration. The holding mechanism is used.

2 and 3, a plurality of holding mechanisms arranged with respect to the cylindrical lens of the first optical system,
7 shows an embodiment with at least one differently configured retaining mechanism.

In the optical scanning device of FIG. 2, the first holding mechanism 18a, the second holding mechanism 18b, and the third holding mechanism 18c are arranged in this order from the light source 10 side in parallel in the optical axis direction of the first optical system. Of the two holding mechanisms, the configuration of the first holding mechanism 18a is different from that of the other holding mechanisms, and for example, the configuration is compatible with a cylindrical lens made of glass, and the second and third holding mechanisms 18b, 1
This is an example of the case where the configurations of 8c are the same and the configuration is compatible with a plastic cylindrical lens. Contrary to the above, the first holding mechanism 18a has a configuration corresponding to the plastic cylindrical lens, and the second and third holding mechanisms 1 are provided.
8b and 18c may be configured to correspond to a glass cylindrical lens.

In the optical scanning device of FIG. 3, the first holding mechanism 18a, the second holding mechanism 18b, and the third holding mechanism 18c are arranged in this order from the light source 10 side in parallel in the optical axis direction of the first optical system. Of the two holding mechanisms, the first and second holding mechanisms 18
The configurations of a and 18b are the same, for example, a configuration corresponding to a cylindrical lens made of glass, and the third holding mechanism 18
This is an example of the case where the configuration of c is different from the others, and the configuration is compatible with a plastic cylindrical lens. Also,
Contrary to the above, the first holding mechanism 18a and the second holding mechanism 1
8b may be a configuration corresponding to a plastic cylindrical lens, and the third holding mechanisms 18b and 18c may be a configuration corresponding to a glass cylindrical lens.

In the above embodiments, the holding mechanism of the cylindrical lens of the first optical system has been taken as an example. However, in the optical scanning device shown in FIGS. 1 and 4, the scanning image forming the second optical system 13 is formed. A plurality of holding mechanisms for holding the lenses may be arranged in parallel in the optical axis direction of the second optical system. In this case, the mounting position of the scanning imaging lens can be changed by selecting the holding mechanism. It is possible to change the image formation state on the surface to be scanned 14, that is, the light spot diameter.

Further, in the optical scanning device of FIG. 1, a third holding mechanism 16 for holding the optical element forming the third optical system 15 is provided.
A plurality of optical elements are arranged in parallel in the optical axis direction of the optical system, and according to a change in the mounting position of the optical element 11b forming the first optical system,
It is also possible to adopt a configuration in which the mounting position of the optical element forming the third optical system 15 is changed.

[0037]

As described above, in the optical scanning device according to the first aspect, the holding mechanism for at least one optical element forming the first optical system, the second optical system, and the third optical system is the optical device. A plurality of elements are arranged according to the mounting position of the element ,
The plurality of holding mechanisms are independently arranged.
Since the configuration is adopted, the optical housing can be shared and the cost can be reduced even if the print speed or the resolution is changed.

According to the optical scanning device of claim 2,
In addition to the configuration and effects of the above, since the plurality of holding mechanisms are all configured to have the same configuration (shape, configuration member, material, etc.), when the optical elements have the same shape, By designing the holding mechanism to have the same structure as described above, the design of the optical housing can be facilitated and simplified.

According to the optical scanning device of claim 3,
In addition to the configuration and effects of the above, the plurality of holding mechanisms are configured such that at least one of the holding mechanisms has a different configuration. Therefore, when the optical elements have different shapes, at least one holding mechanism is provided as described above. By making the mechanism different, the holding mechanism can be optimized according to the optical element to be used.

According to the optical scanning device of claim 4,
Alternatively, in addition to the configuration and effect of 3, the plurality of holding mechanisms are arranged side by side in the optical axis direction of each optical system, which facilitates the layout of the holding mechanisms. You can

In the optical scanning device according to claim 5, the optical scanning device according to claim 4
In addition to the configuration and effects of the above, since the plurality of holding mechanisms are configured to hold the optical elements that form the first optical system, a means for effectively changing the light quantity and the light spot diameter is provided. Can be obtained.

According to the optical scanning device of claim 6,
In addition to the configuration and effects of the above, since the first optical system has an aperture function and the aperture diameter is determined according to the mounting position of the optical element, the light amount and the light spot diameter are determined according to the mounting position of the optical element. It is possible to obtain an optimum opening diameter.

According to the optical scanning device of claim 7,
In addition to the configuration and effect of 6, or a plurality of holding mechanisms, a plurality of holding mechanisms limit the light flux coupled from the light source unit by an opening function, and form a long and narrow line image in the vicinity of the deflection reflection surface of the optical deflector. Since the structure is the holding mechanism for the cylindrical lens of the first optical system, it is possible to obtain means for changing the light quantity and the light spot diameter most effectively.

According to the optical scanning device of claim 8,
In addition to the configuration and effects of 7 or 7, since the aperture diameter is determined so as to change the light amount while keeping the light spot diameter on the surface to be scanned constant, printing is performed when the resolution is constant. You can get a way to improve speed.

According to the optical scanning device of claim 9,
Alternatively, in addition to the configuration and effects of 7, since the aperture diameter is determined so as to change the light spot diameter while keeping the light amount on the scanned surface constant, when the print speed is constant, A means for improving the resolution can be obtained.

According to the optical scanning device of the tenth aspect, in addition to the configuration and effects of the sixth or seventh aspect, the aperture diameter is determined so as to change the light quantity and the light spot diameter on the surface to be scanned. Therefore, it is possible to obtain means for optimizing the light quantity and the light spot diameter with respect to the printing speed and the resolution.

According to the eleventh aspect of the invention, in addition to the configuration and effects of the seventh aspect, a plurality of holding mechanisms are provided, and the first holding mechanism is different from the light source side. Since the second holding mechanism and the third holding mechanism have the same structure, the first holding mechanism is a glass cylindrical lens (or a plastic cylindrical lens).
It is possible to obtain a means for making the holding mechanism, and the second and third holding mechanisms be a holding mechanism for a plastic cylindrical lens (or a glass cylindrical lens).

According to the optical scanning device of the twelfth aspect, in addition to the configuration of the seventh aspect, a plurality of holding mechanisms are provided, and the first holding mechanism and the second holding mechanism are arranged in order from the light source side. Are the same and the third holding mechanism is different, the first and second holding mechanisms are glass cylindrical lens (or plastic cylindrical lens) holding mechanisms, and the third holding mechanism is a plastic cylindrical lens (or Means for providing a holding mechanism for the glass cylindrical lens) can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an optical scanning device showing an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an essential part of an optical scanning device showing another embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a main part of an optical scanning device showing still another embodiment of the present invention.

FIG. 4 is a schematic configuration diagram showing an example of an optical scanning device according to the present invention.

FIG. 5 is a diagram showing a cross section of a main part in the sub-scanning direction of the optical scanning device according to the present invention, which is an explanatory diagram of the position of the cylindrical lens and the aperture diameter when changing the light amount while keeping the light spot diameter constant. is there.

FIG. 6 is a diagram showing a cross section of a main part in the sub-scanning direction of the optical scanning device according to the present invention, which is an explanatory diagram of a cylindrical lens position and an aperture diameter when the light spot diameter is changed while keeping the light amount constant. is there.

[Explanation of symbols]

10: Light source (semiconductor laser) 11a: Coupling lens (optical element of first optical system) 11b: Cylindrical lens (optical element of first optical system) 11c: Aperture (optical element of first optical system) 12: Light deflection Device 12a: Deflection / Reflection Surface 13: Second Optical System 14: Scanned Surface 15: Third Optical System 16: Third Optical System Holding Mechanism 17: Photodetector 18a: First Cylindrical Lens Holding Mechanism 18b: Cylindrical Lens Second holding mechanism 18c: third holding mechanism for cylindrical lens

Front page continuation (72) Iwamatsu Matsumae Izumi Matsumae 1-3-6 Nakamagome, Ricoh Co., Ltd. (56) References JP-A-5-127106 (JP, A) JP-A-62-1 50720 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G02B 26/10

Claims (14)

(57) [Claims] 1. A light source unit, a first optical system for guiding a light beam from the light source unit to an optical deflector, an optical deflector for scanning the light beam, and a scanned light beam on a surface to be scanned. In an optical scanning device comprising a second optical system for converging as a spot, a photodetector section for generating a synchronization signal for determining a writing start position, and a third optical system for guiding a scanned light beam to the photodetector section. , the first optical system, the holding mechanism of the at least one optical element constituting the second optical system and the third optical system are a plurality arranged according to the mounting position of the optical element, the plurality
The optical scanning device is characterized in that each of the holding mechanisms is separately arranged . 2. The plurality of holding mechanisms arranged are all holding mechanisms having the same structure.
The optical scanning device described. 3. The optical scanning device according to claim 1, wherein a plurality of holding mechanisms are provided and at least one of the holding mechanisms has a different structure. 4. The optical scanning device according to claim 2, wherein a plurality of holding mechanisms are arranged in parallel in the optical axis direction of each optical system. 5. The optical scanning device according to claim 4, wherein the plurality of holding mechanisms are holding mechanisms for the optical elements forming the first optical system. 6. The optical scanning device according to claim 5, wherein the first optical system has an aperture function, and the aperture diameter is determined according to the mounting position of the optical element. 7. A plurality of holding mechanisms limit the luminous flux coupled from the light source section by an opening function,
7. The optical scanning device according to claim 5, wherein the optical scanning device is a holding mechanism for the cylindrical lens of the first optical system that forms a long and narrow line image in the vicinity of the deflecting / reflecting surface of the optical deflector. 8. The optical scanning device according to claim 6, wherein the aperture diameter is determined so as to change the light quantity while keeping the light spot diameter on the surface to be scanned constant. 9. The optical scanning device according to claim 6, wherein the aperture diameter is determined so as to change the light spot diameter while keeping the amount of light on the surface to be scanned constant. 10. The optical scanning device according to claim 6, wherein the aperture diameter is determined so as to change the light amount and the light spot diameter on the surface to be scanned. 11. A plurality of holding mechanisms are provided, and the first holding mechanism is different from the light source side in order from the light source side, and the second holding mechanism and the third holding mechanism are the same. The optical scanning device according to claim 7. 12. A plurality of holding mechanisms are arranged, and the first holding mechanism and the second holding mechanism have the same structure and the third holding mechanism has a different structure in order from the light source side. The optical scanning device according to claim 7. 13. A light source section, a coupling lens, and a cylinder.
The first optical system including the drical lens and the light beam are scanned.
Optical deflector and scanning imaging lens such as fθ lens.
The second optical system consisting of
An optical scanning device including a third optical system including the first optical system, the second optical system, and the third optical system.
The holding mechanism for at least one optical element is
Depending on the mounting position of the
The holding mechanism of the
And an optical scanning device. 14. A means for writing an image on a photoconductor,
An image forming apparatus including a scanning device , wherein the optical scanning device is any one of claims 1 to 13.
Image formation using the optical scanning device described in 1.
apparatus.