JP2002082295A - Method for optical scanning, optical scanning device, optical scanning module, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively decrease shading in a divided optical scanning system. SOLUTION: In a method of optical scanning by which a light beam emitted from a light source is deflected by the rotation of a deflecting reflection surface of an optical deflection device, one or more optical spots are formed on a surface to be scanned by converging the deflected light beam upon the surface to be scanned 100 by a scanning and image forming optical system, optical scanning units SUA and SUB, which optically scan a part of the scanned surface with an optical spot, are located in the main scanning direction and a maximum region to be scanned is compositedly optically scanned by the optical scanning by respective optical scanning unit, at least from the light source through the optical deflection device of total optical scanning units SUA and SUB are located on the same base plate 10, the incident directions of the light beams which are made incident from the light source side upon the deflecting reflection surfaces of the corresponding optical deflection devices are reversed with respect to the main scanning direction of the adjacent optical scanning units, and the optical scanning is performed by setting the optical intensities of the light sources of the respective optical scanning units so that the light emitting intensities of the optical spots at the boundary part of partial optical scanning regions which are scanned by the adjacent optical scanning units are equalized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical scanning method, an optical scanning device, an optical scanning module, and an image forming apparatus.

[0002]

2. Description of the Related Art Optical scanning devices are widely known in connection with image forming apparatuses such as digital copying machines, optical printers, optical plotters, and facsimile machines.

In recent years, as the area of the image forming area of these image forming apparatuses has been increased, the optical scanning area also tends to increase. If an attempt is made to scan a long optical scanning area with a single optical scanning optical system, there is a problem that the scanning image forming optical system such as the fθ lens becomes large with an increase in the angle of view, and the wide angle of view is required. There is also a problem that it is difficult to realize an optical system having good optical performance.

As a measure for avoiding such a problem, a light source, an optical deflector, and a scanning image forming optical system are unitized as an optical scanning unit, and the optical scanning area is divided into a plurality of partial optical scanning areas. It has been proposed to optically scan a long optical scanning region synthetically by associating an optical scanning unit with each optical scanning unit and optically scanning each partial optical scanning region by a corresponding optical scanning unit (for example, And JP-A-10-68899). Such an optical scanning method,
Hereinafter, for convenience, it is referred to as a “division light scanning method”.

As an optical deflector used in an optical scanning device, a type which rotates a deflecting reflection surface, such as a rotary polygon mirror, is generally used. In such an optical deflector, the reflection angle of the deflecting light flux changes with the rotation of the deflecting reflection surface, but the reflectance of the deflecting reflection surface changes with the reflection angle. Further, the angle of incidence of the deflected light beam on the lens constituting the scanning image forming optical system changes with the deflection, but the reflectance on the lens surface also changes with the angle of incidence.

For this reason, of the light amount of the light emitted from the light source, the light amount reaching the surface to be scanned by the light spot varies with the image height of the light spot. That is, the light amount of the light spot that scans the surface to be scanned is not uniform in the light scanning area. This phenomenon is known as "shading".

[0007] Of course, shading also occurs in the partial light scanning system. In addition, in the case of the partial light scanning method, since shading occurs for each divided light scanning region, the light amount of the light spot is likely to change discontinuously at the boundary between adjacent partial light scanning regions. If there is a discontinuous change in the light spot light amount, when the written latent image is visualized, the density and resolution of the image change discontinuously at the portion corresponding to the above-mentioned boundary. Deteriorates.

The above-mentioned Japanese Patent Application Laid-Open No. 10-68899 does not mention anything about the shading.

In the partial light scanning method, the surface to be scanned is individually optically scanned for each divided optical scanning area, and the entire optical scanning area is synthetically optically scanned by the optical scanning of each divided optical scanning area. Therefore, an image signal (a set of pixel signals for one line) for writing an image of one line is divided for each optical scanning unit, and modulates the light emission intensity of the light source of the corresponding optical scanning unit.

In the optical scanning device described in JP-A-10-68899, the optical scanning area is divided into two partial optical scanning areas, and the two optical scanning units for optically scanning these two partial optical scanning areas, respectively. The optical scanning directions are opposite to each other, and optical scanning is performed from the boundary between the two partial optical scanning regions toward the opposite end.

The optical scanning device disclosed in Japanese Patent Application Laid-Open No. 10-68899 also uses a telecentric scanning image forming optical system in order to make a light beam that scans a scanned surface orthogonally enter the scanned surface. For this reason, the two optical scanning units must be arranged separately from each other in the sub-scanning direction, and the positional relationship between the two optical scanning units must be carefully adjusted. Further, in order to optically scan the same line of the optical scanning area on the surface to be scanned by the two optical scanning units, a light combining means such as a long half mirror or a polarizing beam splitter is required. In order to provide a large amount of light, it is necessary to increase the amount of light emitted from the light source, or the cost may be increased due to the use of an expensive long beam splitter.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to effectively reduce shading in a divided light scanning system. Another object of the present invention is to realize an optical scanning module suitable for constructing an optical scanning device of a divided optical scanning system. Another object of the present invention is to realize an image forming apparatus for writing an image with the optical scanning device of the divided optical scanning method.

[0013]

According to the optical scanning method of the present invention, a light beam from a light source is deflected by rotation of a deflecting reflection surface of an optical deflector, and the deflected light beam is scanned by a scanning image forming optical system. A plurality of optical scanning units are formed in the main scanning direction by condensing light toward the surface to form one or more light spots on the surface to be scanned, and optically scanning a part of the surface to be scanned by the light spots. An optical scanning method of synthetically optically scanning the largest scanned area by optical scanning by the optical scanning unit.

That is, the optical scanning method of the present invention is a divided optical scanning method, and the partial optical scanning area is optically scanned by each of the plurality of optical scanning units.

Each optical scanning unit "deflects a light beam from a light source by rotation of a deflecting and reflecting surface of an optical deflector, and condenses the deflected light beam toward a surface to be scanned by a scanning image forming optical system. One or more light spots are formed on the surface to be scanned, and a part of the surface to be scanned (that is, a “partial light scanning region”) is optically scanned by the light spot. Therefore, each optical scanning unit has at least a light source, an optical deflector, and a scanning image forming optical system, and the optical deflector is of a type that “deflects the light beam from the light source side by rotating the deflecting reflection surface”. It is.

Since each optical scanning unit forms "one or more light spots" in each partial optical scanning area on the surface to be scanned, the optical scanning in each partial optical scanning area is performed in a "normal single beam system".
And a so-called “multi-beam method”.

The "scanned surface" is actually a photosensitive surface of a "photosensitive medium" such as a photoconductive photosensitive member.

Further, "the maximum scanning area is synthetically optically scanned by optical scanning by each optical scanning unit".

The "maximum scanned area" is the largest area that can be optically scanned synthetically by the all-optical scanning unit. If the image to be formed is not of the maximum size and one line length of the image is smaller than the maximum scanned area, the length required by only some of the optical scanning units but not all of the optical scanning units Can be optically scanned. Of course, even when all the optical scanning units are used, an optical scanning area shorter than the maximum scanned area can be optically scanned. In this case, at least one optical scanning unit optically scans only a part of the corresponding partial optical scanning region.

The optical scanning method according to the first aspect has the following features.

That is, "at least from the light source to the optical deflector" of the all-optical scanning unit is arranged on the same substrate.

The incident direction of the light beam from the light source side to the deflecting / reflecting surface of the corresponding optical deflector is set to be "opposite with respect to the main scanning direction" in the adjacent optical scanning units.

The light scanning is performed by setting the light emission intensity of the light source of each optical scanning unit so that the light intensity of the light spot at the joint of the partial light scanning region optically scanned by the adjacent optical scanning unit is the same. Do. Of course, "the same light intensity" is substantially the same.

In this case, if "the rotation directions of the deflecting and reflecting surfaces of the optical deflectors are aligned in the same direction in all the optical scanning units", the optical scanning directions by the respective optical scanning units become the same, and The “order of pixel information” of the supplied image signal can be the same for all the optical scanning units.

In addition, since "the light intensity of the light source of each optical scanning unit is set so that the light intensity of the light spot at the joint of the partial optical scanning region optically scanned by the adjacent optical scanning unit is the same". In addition, discontinuous changes in image density and resolution can be prevented in an image portion corresponding to a seam portion of the partial light scanning region.

Further, by making the incident direction of the light beam incident on the deflection reflecting surface of the corresponding optical deflector from the light source side to be "opposite with respect to the main scanning direction" by the adjacent optical scanning unit, shading is performed. Can be reversed in adjacent partial light scanning regions, and shading can be reduced over the maximum scanned region.

When the length of the partial optical scanning area in which the optical scanning unit is responsible for optical scanning is called "optical scanning area length", the length of the optical scanning area may vary depending on the optical scanning unit. Can be the same. In this case, assuming that the number of optical scanning units is n, the length of each partial optical scanning area is “maximum scanning area / n”.

In this case, it is preferable that the “optical characteristics of two optical scanning units adjacent to each other” be symmetrical with respect to the joint between the adjacent partial optical scanning regions.

In the above-described optical scanning method, the deflected light beam of each optical scanning unit can be detected by the light receiving element before the start of optical scanning outside the effective scanning area (outside the partial optical scanning area), and based on the detection result. In addition, "the start of optical scanning is synchronized" with each optical scanning unit.

Further, the deflection light beam of each optical scanning unit can be detected by the light receiving element after the completion of the optical scanning outside the effective scanning area. In such a case, a common light receiving element is used in an adjacent part of the optical scanning unit, and the common light receiving element uses the deflected light beam after the light scanning in one optical scanning unit and before the scanning in the other optical scanning unit. Of the light beam can be detected.

When the deflected light beam of each optical scanning unit is detected before the start of optical scanning and after the end of optical scanning, the pixel clock of each optical scanning unit is set according to the difference between the detection times before the start of optical scanning and after the end of optical scanning. Can be adjusted. By doing so, it is possible to prevent overlap or omission of optical scanning at the boundary between adjacent partial optical scanning regions.

The number of optical scanning units arranged in the main scanning direction can be two or three. Of course, four or more optical scanning units can be arranged in the main scanning direction. Good.

An optical scanning device according to the present invention is for implementing the optical scanning method described above. In other words, the optical scanning device of the present invention deflects a light beam from a light source by rotation of a deflecting and reflecting surface of an optical deflector, and condenses the deflected light beam toward a surface to be scanned by a scanning image forming optical system. 1 on the scanned surface
A plurality of optical scanning units are formed in the main scanning direction for forming the above light spots and optically scanning a part of the surface to be scanned by the light spots, and the maximum scanning area is synthesized by optical scanning by each optical scanning unit. Optical scanning device adapted to optically scan optically ".

The optical scanning device according to the second aspect has the following features. That is, at least the light source to the optical deflector of the all-optical scanning unit are arranged on the same substrate.

The incident direction of the light beam incident on the deflection reflecting surface of the corresponding optical deflector from the light source side is set to be opposite to each other with respect to the main scanning direction by the adjacent optical scanning units.

Further, the light emission intensity of the light source of each optical scanning unit is set such that "the light intensity of the light spot at the joint of the partial optical scanning region optically scanned by the adjacent optical scanning unit is the same". .

Since at least the light source to the optical deflector of the all-optical scanning unit are arranged on the same substrate, the positional relationship between the optical scanning units can be easily adjusted.

In the optical scanning device according to the second aspect,
The optical scanning area length of each optical scanning unit can be the same (claim 3). Of course, the length of the light scanning area may be made different depending on the light scanning unit.

In the optical scanning device according to the third aspect, it is preferable that the optical characteristics of the two optical scanning units adjacent to each other are symmetrical with respect to the joint between the adjacent partial optical scanning regions. ).

The optical scanning device according to the second, third, or fourth aspect of the present invention may include a light receiving element for detecting the deflected light beam of each optical scanning unit outside the effective scanning area before the start of the optical scanning. ).

The optical scanning device according to the second, third or fourth aspect of the present invention may have a light receiving element for detecting the deflected light beam of each optical scanning unit outside the effective scanning area after the completion of the optical scanning.

The optical scanning device according to the fifth aspect can also have a light receiving element for detecting the deflected light beam of each optical scanning unit outside the effective scanning area after the end of the optical scanning (claim light 6). A common light receiving element is used in an adjacent portion of the optical scanning unit, and the common light receiving element causes the deflected light beam after the end of the optical scanning in one optical scanning unit and the light beam before the scanning start in the other optical scanning unit. It can be detected (claim 7).

In the optical scanning device according to any one of claims 2 to 7, a semiconductor laser or a semiconductor laser array can be used as a light source of each optical scanning unit, and a partial optical scanning area is provided by each optical scanning unit. When optical scanning is performed by a “multi-beam method”, a light source that combines light beams from a plurality of semiconductor lasers with a combining prism can be used instead of the semiconductor laser array.

In these cases, "from the light source in each optical scanning unit to the scanning image forming optical system" can be arranged on the same substrate (claim 8). In this case, a light receiving element that detects the deflection light beam of each optical scanning unit before the start of the optical scanning and a light receiving element that detects the light beam after the end of the optical scanning can be arranged on the same substrate (claim 9). The light receiving element disposed between the optical scanning units may be "shared by the optical scanning units on both sides" (claim 10).

The optical scanning device according to claim 8, 9 or 10 is characterized in that each optical scanning unit has a coupling between a light source and an optical deflector for coupling a light beam from the light source to a subsequent optical system. It has a lens, an aperture for beam shaping, and a cylindrical lens, and can form a light beam from the light source side at the position of the deflecting reflection surface of the optical deflector as a linear image long in the main scanning direction. " Of course, these coupling lenses, apertures, and cylindrical lenses are arranged on the same substrate.

In the above optical scanning device, a "rotating polygon mirror" can be used as the optical deflector. As the optical deflector, a rotating single-sided mirror or a rotating two-sided mirror can be used other than the rotating polygon mirror.

In the above optical scanning device, the number of optical scanning units arranged in the main scanning direction can be two or three. Of course, four or more units can be arranged.

In the optical scanning device according to any one of claims 2 to 7, "at least a part of the scanning image forming optical system in each optical scanning unit is not arranged on the same substrate".
(Claim 11). In this case, the scanning image forming optical system in each optical scanning unit is constituted by two lenses, and the light source to the light source side lens of the scanning image forming optical system in each optical scanning unit is arranged on the same substrate. (Claim 12).

In this case, of the two lenses constituting the scanning image forming optical system in each optical scanning unit, the lens (lens on the surface to be scanned) which is not arranged on the same substrate is referred to as a lens in the main scanning direction. It is possible to adopt a configuration of "array integration" (claim 13).

Of course, the configuration of the scanning image forming optical system is not limited to the above case. The scanning image forming optical system can be constituted by, for example, one lens, or can be constituted by three or more lenses, and furthermore, a reflecting mirror having an image forming function or one surface having an image forming function A scanning image forming optical system can be constituted by the above-mentioned reflecting mirror and one or more lenses.

When a scanning image forming optical system is constituted by a plurality of optical elements (lenses and reflecting mirrors), a part or all of the
It can be arranged on the same substrate with other parts of the optical scanning unit.

In the above-described optical scanning device, the light source of the optical scanning unit may be a semiconductor laser or a semiconductor laser array, and “a portion of each optical scanning unit arranged on the same substrate” may be defined as: Each of the optical scanning modules can be modularized as an “optical scanning module”, and each optical scanning module can be fixedly arranged on the same substrate.

In the optical scanning device according to the fourteenth aspect, "two types of modules having substantially mirror-symmetrical structures" are prepared as optical scanning modules, and these two types of optical scanning modules are alternately arranged in the main scanning direction. (Claim 15).

Here, the mirror symmetry means that one module has a configuration in which the other module is mirrored. That is, the two types of optical scanning modules are substantially mirror-symmetric with respect to each other.

In the optical scanning device according to the fifteenth aspect, at least “a light source, a coupling lens, and an optical deflector” are integrally disposed in the two types of optical scanning modules having structures that are substantially mirror-symmetrical to each other. (Claim 1
6), the optical deflector of each optical scanning module can be a rotating polygon mirror.

In the above-described optical scanning device, the coupling lens of each optical scanning module may be configured such that “the light beam from the light source is substantially parallel in the main scanning direction, and is near the position of the deflecting reflection surface of the optical deflector in the sub-scanning direction. Having a function of forming a long line image in the main scanning direction ”.
In addition, two types of optical scanning modules having structures that are substantially mirror-symmetrical to each other can have lenses that constitute a part of the scanning image forming optical system.

16. The optical scanning device according to claim 15, wherein each of the two types of optical scanning modules having a substantially mirror-symmetrical structure is coupled to a light source and a light flux from the light source to an optical system thereafter. A lens, an optical deflector, and a lens constituting a part of the scanning image forming optical system,
The whole is formed in a housing shape "(claim 17). In this case, each optical scanning module can have a “folded reflecting surface that directs the light beam emitted from the coupling lens to the deflecting and reflecting surface of the optical deflector and reflects back” (claim 18).

The optical scanning device according to claim 17 or 18, wherein a lens constituting a part of the scanning image forming optical system of each optical scanning module is provided so as to “close a window provided in the housing”. (Claim 19).

In the optical scanning device according to the present invention, each optical scanning module may tilt the optical path of the deflected light beam deflected by the optical deflector with respect to the same substrate on which each optical scanning unit is provided. Optical path bending reflecting surface that bends in the direction ".
0).

In the optical scanning device according to the seventeenth aspect, each of the optical scanning modules includes a “folded reflecting surface that directs a light beam emitted from the coupling lens to the deflecting and reflecting surface of the optical deflector, and that reflects the light beam; And a light path bending reflecting surface that bends the light path of the deflected light beam deflected by the light deflector in a direction inclined with respect to the same substrate on which each optical scanning unit is provided. Has a function of forming a light beam from the light source into a substantially parallel light beam in the main scanning direction, converging it in the sub-scanning direction, and forming a long line image in the main scanning direction near the deflecting reflection surface of the rotary polygon mirror. And a lens constituting a part of the scanning image forming optical system can be “provided so as to cover a window provided in the housing”.

In this case, the electrode substrate, the middle substrate, the frame, and the sealing plate are integrally formed on each of the optical scanning modules with the “rotating shaft of the rotary polygon mirror and the lead terminals” on the electrode substrate. The middle substrate is provided with "a through hole through which the rotating shaft passes, and a light source, a coupling lens, and a driving coil for driving a rotating polygon mirror". The middle substrate is disposed on the electrode substrate. Through the through-hole, the frame is formed with a “reflected reflection surface and an optical path bending reflection surface”, and this frame is arranged on a middle substrate, and fitted with a light source, a coupling lens, and a rotation shaft. A space for accommodating the rotating polygon mirror is formed, a "window portion" is formed in the sealing plate, the sealing plate is arranged on a frame, the space is closed, and "scanning" is performed so as to close the window portion. A lens that constitutes a part of the imaging optical system,
The deflected light beam reflected by the optical path bending reflecting surface can be emitted through the lens provided in the window, and the middle substrate of each optical scanning module is a "silicon substrate", and the light source is integrally formed with the middle substrate. The frame of each optical scanning module can be formed using “single crystal silicon” as a material,
The reflection surface shape of the folded reflection surface and the optical path bending reflection surface can be formed by “anisotropic etching”.

In such an optical scanning device, "the interior of the housing of each optical scanning module is kept confidential and the pressure inside is reduced". In this way, the air resistance against rotation of the deflecting and reflecting surface of the optical deflector can be reduced, and high-speed deflection can be easily performed.

In addition, it is possible to keep the inside of the housing of each optical scanning module in a confidential state and fill the inside with a gas for preventing oxidation such as nitrogen.

In the above-described optical scanning device, the number of optical scanning units arranged in the main scanning direction can be two or three. Of course, four or more optical scanning units can be used.

The optical scanning module according to the present invention is arranged such that a light beam from a light source is deflected by rotation of a deflecting and reflecting surface of an optical deflector, and the deflected light beam is condensed toward a surface to be scanned by a scanning image forming optical system. Forming one or more light spots on the surface to be scanned, and arranging a plurality of optical scanning units in the main scanning direction for optically scanning a part of the surface to be scanned by the light spot;
By optical scanning by each optical scanning unit, the maximum scanned area is synthetically optically scanned, and at least from the light source to the optical deflector of the all optical scanning unit is arranged on the same substrate, corresponding from the light source side The incident direction of the light beam incident on the deflecting / reflecting surface of the optical deflector is set to be opposite to each other with respect to the main scanning direction in the adjacent optical scanning unit, and the partial light beam optically scanned by the adjacent optical scanning unit is set. Used as a part of each light scanning unit in an optical scanning device that performs light scanning by setting the light emission intensity of the light source of each light scanning unit so that the light intensity of the light spot at the seam portion of the scanning area is the same. Optical scanning module ".

There are two types of optical scanning modules, each of which has a semiconductor laser or a semiconductor laser array as a light source as a part of each optical scanning unit, and at least a coupling lens and an optical deflector. It is modularized. " And these 2
The types of optical scanning modules are formed substantially mirror-symmetrical to each other, and are fixedly arranged on the same substrate by combining these two types of modules.

An optical scanning module according to a twenty-first aspect is an optical scanning module that forms one of the two types of modules. An optical scanning module according to a twenty-second aspect is an optical scanning module formed substantially mirror-symmetric with respect to the optical scanning module according to the twenty-first aspect.

In the optical scanning module according to claim 21 or 22, the optical deflector in the module can be a rotating polygon mirror. Then, the coupling lens in the module is referred to as “a light beam from the light source is formed into a substantially parallel light beam in the main scanning direction, and a line image is formed near the position of the deflecting reflection surface of the optical deflector in the sub-scanning direction as a long image in the main scanning direction. With an image-capturing function. "

Further, the optical scanning module can have “a lens that constitutes a part of the scanning image forming optical system”.
In this case, the optical scanning module includes a light source, a coupling lens that couples a light beam from the light source to a subsequent optical system, an optical deflector, and a lens that forms a part of the scanning image forming optical system. , Formed entirely in a housing shape ". In this case, it is possible to have a “folded reflecting surface that directs the light beam emitted from the coupling lens to the deflecting reflecting surface of the optical deflector and reflects the light back”. It can also be provided so as to “close a window provided in the housing”.

The optical scanning module may have “an optical path bending / reflecting surface that bends the optical path of the deflected light beam deflected by the optical deflector in the direction inclined to the same substrate on which each optical scanning unit is provided”.

The optical scanning module also includes a “reflection reflecting surface for directing the light beam emitted from the coupling lens to the deflecting reflection surface of the optical deflector and reflecting the light beam, and an optical path for the deflected light beam deflected by the optical deflector. A light path bending reflecting surface that bends in the direction inclined with respect to the same substrate on which each optical scanning unit is provided; the optical deflector is a rotating polygon mirror; and the coupling lens is a light beam from the light source that is substantially in the main scanning direction. A lens that has a function of forming a parallel light beam, converging in the sub-scanning direction, and forming an image as a long linear image in the main scanning direction in the vicinity of the deflecting reflection surface of the rotary polygon mirror, and constituting a part of the scanning image forming optical system Is provided so as to cover a window provided in the housing. " In this case, the optical scanning module can include an electrode substrate, a middle substrate, a frame, and a sealing plate.

The rotating shaft of the rotating polygon mirror and the lead terminals are integrally formed on the electrode substrate.

The middle substrate is provided with a through hole through which the above-mentioned rotary shaft passes, and a light source, a coupling lens, and a driving coil for driving a rotary polygon mirror are provided. Then, the middle substrate is disposed on the electrode substrate with the above-described rotating shaft penetrating through the through hole.

The frame is provided with a folded reflecting surface and an optical path bending reflecting surface. By arranging this frame on the middle substrate, a space for accommodating the light source, the coupling lens, and the rotating polygon mirror fitted with the rotating shaft is formed.

The sealing plate forms a window. Then, the sealing plate is arranged on a frame to close the space. Further, a “lens constituting a part of the scanning image forming optical system” is provided in the formed window portion so as to close the window portion, and a lens provided in the window portion with the deflected light beam reflected by the optical path bending reflection surface. Inject through

In the optical scanning module, the middle substrate is a silicon substrate, and the light source can be formed integrally with the middle substrate. In the optical scanning module, the frame can be formed of single crystal silicon, and the reflection surface shape of the return reflection surface and the optical path bending reflection surface can be formed by anisotropic etching. The inside of the housing can be kept secret and a gas for preventing oxidation such as nitrogen can be sealed inside.

The image forming apparatus of the present invention is “an image forming apparatus that forms a latent image by performing optical scanning on a photosensitive surface of a photosensitive medium and visualizes the formed latent image to form an image”.
The optical scanning device according to any one of claims 2 to 20 is used as an optical scanning device for optically scanning a photosensitive surface of a photosensitive medium (claim 23).

The photosensitive surface of the photosensitive medium forms the actual surface to be scanned in the optical scanning method / optical scanning apparatus described above.

As the "photosensitive medium", a silver salt film or a photoconductive photoreceptor can be used. When a silver halide film is used as a photosensitive medium, a latent image formed by optical scanning by an optical scanning device can be visualized according to a normal silver halide photographic process.

When a silver halide photograph is used as the photosensitive medium in the image forming apparatus of the present invention, the image forming apparatus can be implemented as a well-known optical plate making apparatus or optical drawing apparatus.

When a photoconductive photoreceptor is used as the photosensitive medium, the latent image is formed as an electrostatic latent image by uniformly charging the photoreceptor and writing by optical scanning, and is visualized as a toner image. The visualized toner image can be directly fixed to the photoreceptor when the photoreceptor is sheet-like, such as zinc oxide paper. If the photoconductor is used repeatedly, transfer the toner image to transfer paper or an OHP sheet (plastic sheet for overhead projector)
An image is obtained by transferring and fixing to a “sheet-shaped recording medium” as described above.

Such an image forming apparatus can be implemented as a digital copying machine, an optical printer, an optical plotter, a facsimile machine, or the like.

[0083]

Embodiments of the present invention will be described below.

In FIG. 1, reference numerals SUA and SUB indicate “optical scanning units”. Optical scanning unit SUA
Is a semiconductor laser 1A as a light source, a coupling lens 2A, and an aperture 3 for beam shaping, as shown in FIG.
A, a cylindrical lens 4A, a rotating polygon mirror 5A as an optical deflector, and a scanning lens 6A forming a scanning image forming optical system have a predetermined positional relationship. Similarly, the optical scanning unit S
UB is a semiconductor laser 1B as a light source,
A coupling lens 2B, a beam shaping aperture 3B, a cylindrical lens 4B, a rotating polygon mirror 5B as an optical deflector, and a scanning lens 6B forming a scanning image forming optical system have a predetermined positional relationship.

These optical scanning units SUA, SUB
Are arranged on the same substrate 10. As shown in the figure, mirrors m1, m2, and m3, light receiving elements PD1, PD2, and PD3 are provided on the substrate 10, and a controller 12 and a signal processing unit 14 are further provided.

When the semiconductor laser 1A emits light, the emitted light beam is converted by the coupling lens 2A into a light beam form suitable for the subsequent optical system. The converted light beam form may be a parallel light beam, a divergent light beam with reduced divergence, or a focused light beam. Here, for the sake of specificity, the light beam from the light source is
A is assumed to be converted into a parallel light beam by A.

The light beam emitted from the coupling lens 2A then passes through the aperture of the aperture 3A so that the light beam peripheral portion is shielded and beam-shaped, and is collected by the cylindrical lens 4A in the sub-scanning direction (the direction perpendicular to the drawing). The light is formed and forms an image near the deflection reflecting surface of the rotary polygon mirror 5A as a "long line image in the main scanning direction".

The luminous flux reflected by the deflecting / reflecting surface becomes a deflecting luminous flux which is deflected at a constant angular velocity with the constant speed rotation of the rotary polygon mirror 5A in the direction of the arrow (clockwise), and is incident on the scanning lens 6A. The light is condensed as a light spot on the surface to be scanned 100 by the action of, and the portion of the partial optical scanning area PA is optically scanned.

Similarly, when the semiconductor laser 1B emits light, the emitted light beam is converted into a parallel light beam by the coupling lens 2B, the beam is shaped by the aperture 3B, and the deflection of the rotary polygon mirror 5B is performed by the action of the cylindrical lens 4B. An image is formed near the reflecting surface as a long line image in the main scanning direction.

Then, the light is deflected at a constant angular velocity with the clockwise rotation of the rotary polygon mirror 5B, and is condensed as a light spot on the surface to be scanned 100 by the action of the scanning lens 6B, and the partial light scanning area PB Is optically scanned.

The “optical elements from the light source to the scanning lens” constituting the optical scanning units SUA and SUB are the same as each other. The optical scanning units SUA and SUB are configured to be “substantially mirror-symmetrical” as shown in the figure. Therefore, the incident directions of the light beams from the light source side to the deflecting reflection surface of the rotary polygon mirror are opposite to each other in the main scanning direction.

The light beam deflected by the light scanning unit SUA is reflected by the mirror m1 and detected by the light receiving element PD1 prior to optically scanning the partial light scanning area PA, and is reflected by the mirror m2 after the completion of the light scanning to receive the light receiving element PD2. Is detected.

Prior to optically scanning the partial optical scanning area PB, the deflected light beam of the optical scanning unit SUB is reflected by the mirror m2 and detected by the light receiving element PD2, and after the light scanning is completed, reflected by the mirror m3 and detected by the light receiving element PD3. Is detected.

The controller 12 is constituted by a microcomputer or the like, and controls the optical scanning units SUA and SUB and the signal processing section 14.

The image information to be written on the scanned surface 100 by optical scanning is pixel information obtained by reading an original, image information generated by a computer or the like, or information read from a floppy disk or the like. Input to the unit 14. Under the control of the controller, the signal processing unit 14 converts the input signal into writable image pixel information, and divides the input signal into two for each line of information to be written. One of the divided information is one of the optical scanning units SUA To modulate the light intensity of the semiconductor laser 1A,
Written in A.

The other of the divided information is applied to the optical scanning unit SUB, modulates the light intensity of the semiconductor laser 1B, and is written in the partial optical scanning area PB.

All outputs from the light receiving elements PD1, PD2, PD3 are input to the controller 12. Controller 1
2, based on these inputs, each optical scanning unit SUA,
The start of SUB writing is synchronized, and the optical scanning units SUA and SUB correspond to the corresponding partial optical scanning areas PA and PB.
The clock for pixel writing is adjusted based on the time required for the optical scanning of (1), so that overlapping writing and lack of writing do not occur in the joint portion C1 of the partial optical scanning areas PA and PB.

The controller 12 also controls the seam portion C
In 1, the light intensity of the semiconductor lasers 1A and 1B is set so that the light intensity of the light spot of the light scanning unit SUA and the light intensity of the light spot of the light scanning unit SUB are equal.

FIG. 2 shows optical scanning units SUA, SUB,
Using the SUC, the partial light scanning area PA of the scanned portion 100,
1 shows an embodiment of an optical scanning device that optically scans PB and PC synthetically.

The optical scanning units SUA and SUb are the same as those described with reference to FIG. 1, and the optical scanning unit SUC is the same as the optical scanning unit SUA. Reference numeral M4 indicates a mirror, and reference numeral PD4 indicates a light receiving element.

The light beam deflected by the light scanning unit SUA is transmitted to the light receiving elements PD1 and PD1 before and after the light scanning of the partial light scanning area PA.
2 and the light beam deflected by the optical scanning unit SUB before and after optical scanning of the partial optical scanning area PB,
2. The light beam received by PD3 and the deflected light beam of optical scanning unit SUC are received by light receiving elements PD3 and PD4 before and after optical scanning of partial optical scanning area PC.

Image information to be written on the scanned surface 100 by optical scanning (pixel information obtained by reading an original, image information generated by a computer or the like, or information read from a floppy disk or the like) is processed by the signal processing unit 14. Is input to the signal processing unit 14 under the control of the controller, converts the input signal into writable image pixel information, divides the information into one line of information for writing, and divides the information into three by three. One is applied to the optical scanning unit SUA and written into the partial optical scanning area PA. Another one of the divided information is applied to the optical scanning unit SUB and written to the partial optical scanning area PB, and the other one is applied to the optical scanning unit SUC and written to the partial optical scanning area PC. It is.

The controller 12 includes light receiving elements PD1, P
D2, PD3, and PD4 receive the input and synchronize the writing start of each optical scanning unit SUA, SUB, and SUC, and the partial optical scanning areas PA, PB, and PC corresponding to the optical scanning units SUA, SUB, and SUC. The clock for pixel writing is adjusted based on the time required for the optical scanning of the partial optical scanning areas PA, PB, and PC in the joints C1 and C2.
In addition to preventing duplicate writing or lack of writing from occurring, the light sources of the respective optical scanning units (S1, S2, S3) are set so that the light intensity of the light spots of the optical scanning units SUA, SUB, SUC becomes equal at the joints C1, C2. The emission intensity of the semiconductor laser is set.

That is, in the optical scanning device shown in FIG. 1 (FIG. 2), the light beam from the light source is deflected by the rotation of the deflecting / reflecting surface of the optical deflector, and the deflected light beam is scanned and imaged. Light that converges toward the scanned surface 100 by the system to form one or more light spots on the scanned surface, and optically scans a portion PA, PB (and PC) of the scanned surface 100 with the light spot. Scanning units SUA, SUB (and SUC)
Are arranged in the main scanning direction, and the maximum scanning area (PA + PB or PA + PB + PC) is optically scanned synthetically by optical scanning by each optical scanning unit. Then, on the same substrate 10, at least the light source to the optical deflector of the all-optical scanning unit are arranged. Further, the rotation directions of the deflecting and reflecting surfaces of all the optical deflectors arranged on the substrate 10 are the same (clockwise).
Are aligned.

The incident direction of the light beam from the light source side to the corresponding deflecting / reflecting surface of the optical deflector depends on the main scanning direction (horizontal direction in the drawing) between the adjacent optical scanning units SUA and SUB (SUB and SUC). They are set in opposite directions.

The light emission intensity of the light source of each optical scanning unit is set so that the light intensity of the light spot at the joint C1 (and C2) of the partial optical scanning region optically scanned by the adjacent optical scanning unit is the same. (Claim 1,
2).

In the optical scanning device shown in FIGS. 1 and 2,
The optical scanning area length PA, PB (and PC) of each optical scanning unit SUA, SUB (and SUC) is the same (claim 3). The optical characteristics of the two optical scanning units adjacent to each other are symmetrical with respect to the joint between the adjacent partial optical scanning regions.

The light receiving elements PD1, PD2 (and PD) which detect the deflection light beams of the respective optical scanning units SUA, SUB (and SUC) outside the effective scanning area before the start of optical scanning.
3).

Further, each optical scanning unit SUA, SUB
(And SUC) light-receiving elements PD2 and PD3 for detecting the deflected light beam outside the effective scanning area after the optical scanning is completed.
(And PD4), and a common light receiving element PD2 (and PD3) is used adjacent to the optical scanning unit. Of the optical scanning unit before the start of scanning is detected (claim 7).

The light source of each optical scanning unit SUA, SUB (and SUC) is a semiconductor laser, and the components from the light source to the scanning image forming optical system in each optical scanning unit are arranged on the same substrate 10. , The light receiving elements PD1 and P2 that detect the deflection light beam of each optical scanning unit before the start of optical scanning.
D2 (and PD3) and light receiving elements PD2 and PD3 (and PD4) to be detected after the completion of the optical scanning are arranged on the same substrate 10 (claim 9).

The light receiving elements PD2 and PD3 arranged between the optical scanning units are shared by the optical scanning units on both sides thereof.

Each of the optical scanning units SUA and SUB (the optical scanning unit SUC is the same as the optical scanning unit SUA) transmits a light beam from the light source between the light sources 1A and 1B and the optical deflectors 5A and 5B. And a coupling lens 2A, 2B for coupling to the optical system, apertures 3A, 3B for beam shaping, and cylindrical lenses 4A, 4B. An image is formed at the position as a line image long in the main scanning direction. The optical deflectors are rotary polygon mirrors 5A and 5B.

In the optical scanning device shown in FIG. 1, two optical scanning units are arranged in the main scanning direction. In the optical scanning device shown in FIG. 3, three optical scanning units are arranged in the main scanning direction. .

In the embodiments shown in FIGS. 1 and 2, a semiconductor laser array is used as a light source instead of the semiconductor lasers 1A, 1B, etc., so that each partial light scanning region is scanned by a multi-beam method. You may.

FIG. 3 schematically shows another embodiment of the optical scanning device. In order to avoid complication, the same symbols as those in FIG. Portions denoted by the same reference numerals as those in FIG. 1 are the same as those in FIG. 1, and therefore description thereof will be omitted.

In this embodiment, the same substrate 1
The optical scanning modules MA and MB are fixed on 0 with a predetermined positional relationship. Optical scanning module MA, MB
Is formed in a housing shape and, as described later, is a module from a light source in the optical scanning unit to “a part of the scanning image forming optical system”. That is, in this embodiment, the scanning image forming optical element in each optical scanning unit (deflected light beam emitted from the light source of each optical scanning unit and deflected by the optical deflector is applied to the partial optical scanning area on the scanning surface 100). (Condensed as a light spot) is composed of two scanning lenses.

Of these two scanning lenses, the scanning lenses L1A and L1B disposed on the light source side are provided so as to cover the “window provided in the housing” of the optical scanning module as shown in FIG. The scanning lens on the scanning surface side is provided separately from the optical scanning module. The scanning lenses L1A and L1B are lenses having the same optical characteristics.

In FIG. 3, reference numerals L2A and L2B denote a "scanning lens on the surface to be scanned". In the embodiment of FIG. 3, the two scanning lenses L2A and L2B are integrated as a lens array LA1. Scan lens L
2A and L2B are lenses having the same optical characteristics.

The deflected light beams emitted from the respective optical scanning modules MA and MB are deflected in a plane orthogonal to the common base 10 holding the optical scanning modules MA and MB. The light receiving elements PD1 and PD2 for detecting the deflected light beam before and after the optical scanning are provided on the substrate 10, but the deflected light beam is detected by the light receiving elements PD1 and PD2.
The mirrors m1 and m2 that reflect toward the PD2 are provided at positions away from the substrate 10.

FIG. 4 schematically shows an embodiment in which the embodiment of FIG. 3 is extended to use three optical scanning units “following the embodiment of FIG. 2”. 4, in order to avoid complication, the same components as those in FIG. 2 are denoted by the same reference numerals as those in FIG. 2, and description thereof is omitted.

The optical scanning modules MA and MB used for optical scanning of the partial optical scanning areas PA and PB are the same as those in FIG. The optical scanning module MC used for optical scanning of the partial optical scanning area PC is an optical scanning module M
Same as A. Further, reference numerals L1A, L1B, L
The “scanning lens on the light source side of the two scanning lenses constituting the scanning imaging optical system” shown by 1C has the same optical characteristics, and these are provided in the optical scanning modules MA, MB, and MC, respectively. I have.

Reference numeral LA2 denotes a scanning lens L on the surface to be scanned.
2A shows a lens array in which 2A, L2B, and L2C (having the same optical characteristics) are integrated.

FIG. 5 is an explanatory diagram showing the optical arrangement (excluding the scanning lens on the light source side) inside the optical scanning module.

FIG. 5 (a) relates to the optical scanning module MA, and FIG. 5 (b) relates to the optical scanning module MB.

Reference numerals 1A and 1B denote semiconductor lasers as light sources, reference numerals 2A 'and 2B' denote coupling lenses, and reference numeral 5
Reference numerals A and 5B denote rotating polygon mirrors as optical deflectors, and reference numeral ML1.
A and ML1B denote a “folded reflecting surface that directs the light beam emitted from the coupling lens to the deflecting / reflecting surface of the optical deflector and reflects the light beam back”. An optical path bending reflecting surface that bends the optical path in a direction inclining with respect to the same substrate on which each optical scanning unit is provided is shown.

The divergent light beams emitted from the light sources 1A and 1B are converted by the coupling lenses # 2A 'and 2B' into a light beam form suitable for the subsequent optical system. In the embodiment being described, the coupling lenses 2A 'and 2B'
The light beams emitted from the light source become substantially parallel light beams in the main scanning direction, and become focused light beams in the sub-scanning direction.

Each light beam emitted from the coupling lenses 2A 'and 2B' is reflected by the return reflecting surfaces ML1A and ML1B toward the deflecting reflecting surfaces of the rotating polygon mirrors 5A and 5B, and is located near the deflecting reflecting surface of each rotating polygon mirror. An image is formed as a "long line image in the main scanning direction".

The light beam deflected by the rotation of the rotary polygon mirrors 5A, 5B in the direction of the arrow (clockwise) is reflected by the optical path bending reflection surfaces ML2A, ML2B in a direction orthogonal to the drawing of FIG. 3, the scanning lenses L1A, L shown in FIG.
The light is emitted from the optical scanning module via 1B and L1C.

As shown in FIG. 5, the optical scanning module M
A and MB are formed substantially mirror-symmetrical to each other, and as described above, the optical scanning module MC in FIG. 4 is the same as the optical scanning module MA.

Referring to FIGS. 3 and 4, the deflected light beams emitted from the optical scanning modules MA and MB (and MC) are applied to the corresponding scanning lenses L2A and L2B (and L2, respectively).
2C) to form a light spot on the surface to be scanned 100, and the partial light scanning areas PA and PB (and PC) respectively.
Is optically scanned.

Scanning lenses L1A and L2A, L1B and L2
Each of the scanning image forming optical systems constituted by B (and L1C and L2C) constitutes an "anamorphic fθ lens", and has a function of correcting surface tilt in each rotating polygonal mirror and making optical scanning uniform. Have.

Before and after the light scanning of each partial light scanning area, each deflected light beam is applied to the light receiving elements PD1, PD2 (and PD3, PD3).
4), the start of optical scanning is synchronized, and the adjustment of the pixel clock prevents duplicate writing and missing writing in the seam portion C1 (and C2) of the partial optical scanning region. . The processing of the image signal for writing is the same as in FIGS.

In the embodiments shown in FIGS. 3 and 4, the emission intensity of each semiconductor laser is controlled by the controller (not shown in FIGS. 3 and 4). The light spots at C1 (and C2) are set to have the same light intensity.

As described above, the optical scanning module MA (and MC) and the optical scanning module MB are substantially mirror-symmetrical to each other, so that the light source side moves from the light source side to the corresponding deflecting surface of the corresponding optical deflector. The incident directions of the incident light beams are opposite to each other with respect to the main scanning direction in the adjacent optical scanning units.

That is, the optical scanning device described in the embodiment with reference to FIGS. 3 to 5 deflects a light beam from a light source by rotation of a deflecting reflection surface of an optical deflector, and scans the deflected light beam. An optical scanning unit that forms one or more light spots on the surface to be scanned by condensing light toward the surface to be scanned by the imaging optical system, and optically scans a part of the surface to be scanned with the light spot, in a main scanning direction. In an optical scanning device in which a maximum scanning area is synthetically optically scanned by optical scanning by each optical scanning unit, all the optical scanning units of at least a light source are arranged on the same substrate 10. Arranging up to the light deflector, the incident direction of the light beam incident on the deflection reflecting surface of the corresponding light deflector from the light source side, in the adjacent optical scanning unit, set to be opposite to each other with respect to the main scanning direction, Adjacent optical scanning unit So that the light intensity of the light spot are the same in the portion of the seam of the partial light scanning region which is more light scanning an optical scanning device which sets the light emission intensity of the light source of the optical scanning unit (claim 2).

The optical scanning area lengths PA and PB (and PC) of each optical scanning unit are the same (claim 3), and the optical characteristics of two optical scanning units adjacent to each other are the same as those of the adjacent partial optical scanning area. It is symmetric with respect to the seam C1 (and C2) (claim 4), and the deflected light beam of each optical scanning unit is detected by the light receiving elements PD1, PD2 (and PD3) before the start of optical scanning outside the effective scanning area. After completion of the optical scanning, the light is detected by the light receiving elements PD2 and PD3 (and PD4) (claim 6).

Further, a common light receiving element PD2 (and PD3) is used adjacent to the optical scanning unit, and the deflected light beam after the light scanning in one of the optical scanning units is completed by the common light receiving element. The light beam before scanning in the optical scanning unit is detected (claim 7).

The light source of each optical scanning unit is a semiconductor laser.

Further, in the optical scanning device according to the embodiment shown in FIGS. 3 and 4, at least a part (scanning lenses L2A, L2B (and L2A) of the scanning image forming optical system in each optical scanning unit.
2C)) are not arranged on the same substrate 10 (claim 1).
1) The scanning image forming optical system in each optical scanning unit has two lenses L1A and L2A, L1B and L2B (and L1
C and L2C), and in each optical scanning unit, a lens L1A on the light source side of the scanning image forming optical system from the light source.
Up to L1B (and L1C) are arranged on the same substrate 10 (claim 12).

Further, of the two lenses constituting the scanning image forming optical system in each optical scanning unit, the same substrate 10 is used.
The lenses L2A, L2B (and L
2C) are arranged and integrated in the main scanning direction (claim 13).

Further, the light source of the optical scanning unit is a semiconductor laser, and the portions of each optical scanning unit arranged on the same substrate 10 are optical scanning modules MA and MB, respectively.
(And MC), and each optical scanning module is fixedly arranged on the same substrate 10 (claim 14).

As shown in FIG. 5, there are two types of optical scanning modules having a structure that is substantially mirror-symmetrical to each other, and these two types of optical scanning modules are alternately arranged in the main scanning direction ( The two types of optical scanning modules having substantially mirror-symmetrical structures include at least the light sources 1A and 1B and the coupling lenses 2A 'and 2B'.
And the optical deflectors 5A and 5B are integrally disposed (claim 16), and the optical deflectors of each optical scanning module are rotary polygon mirrors.

The coupling lenses 2A 'and 2B' of each optical scanning module MA and MB convert the light beam from the light source into a substantially parallel light beam in the main scanning direction and the deflecting / reflecting surface of the optical deflector in the sub-scanning direction. Two types of optical scanning modules MA and MB having a function of forming a line image long in the main scanning direction in the vicinity of the position and having structures that are substantially mirror symmetric with each other are lenses that constitute a part of the scanning imaging optical system. It has L1A and L1B.

Each of the two types of optical scanning modules MA and MB having a structure that is substantially mirror-symmetrical to each other includes light sources 1A and 1A, respectively.
B, coupling lenses 2A 'and 2B' for coupling the light beam from the light source to the subsequent optical system, and an optical deflector 5
A, 5B and a lens L constituting a part of the scanning image forming optical system
1A and L1B, the entirety of which is formed in a housing shape (claim 17), and each of the optical scanning modules MA and MB directs the light beam emitted from the coupling lens to the deflecting and reflecting surface of the optical deflector. Return reflecting surface ML1A, ML1 that reflects back
B (Claim 18), and the lenses L1A and L1 constituting a part of the scanning image forming optical system of each optical scanning module.
1B is provided so as to cover a window provided in the housing (claim 19).

Each of the optical scanning modules MA and MB has an optical path bending / reflecting surface ML2A or ML2B which bends the optical path of the deflected light beam deflected by the optical deflector with respect to the same substrate 10 on which each optical scanning unit is provided. (Claim 20).

That is, each of the optical scanning modules MA and MB described with reference to FIGS. 3 to 5 has a folded reflection surface for directing a light beam emitted from a coupling lens to a deflecting reflection surface of an optical deflector and for reflecting the light beam back. The optical deflector 5 includes: ML1A and ML2A; and optical path bending and reflecting surfaces ML2A and ML2B that bend the optical path of the deflected light beam deflected by the optical deflector with respect to the same substrate on which each optical scanning unit is provided.
A and 5B are rotating polygon mirrors, and coupling lenses 2A ',
Reference numeral 2B ′ denotes that the light beam from the light source is made substantially parallel light beam in the main scanning direction and is converged in the sub-scanning direction.
The lens L1A, L1B that forms a long line image in the main scanning direction in the vicinity of the deflecting reflection surface of B and forms a part of the scanning image forming optical system closes a window provided in the housing. It is provided as follows.

Therefore, according to the optical scanning apparatus shown in FIGS. 1 to 4, the light beam from the light source is deflected by the rotation of the deflecting and reflecting surface of the light deflector, and the deflected light beam is scanned and formed. An optical scanning unit that condenses light toward the surface to be scanned 100 by the image optical system to form one or more light spots on the surface to be scanned, and optically scans a part of the surface to be scanned with the light spot, in the main scanning direction In an optical scanning method in which a maximum scanning area is synthetically optically scanned by optical scanning by each optical scanning unit, at least a light source of an all-optical scanning unit and an optical deflector are arranged on the same substrate 10. Are arranged so that the incident direction of the light beam incident on the deflection reflection surface of the corresponding light deflector from the light source side is opposite to the main scanning direction in the adjacent optical scanning units, and the adjacent optical scanning units By light An optical scanning method for performing optical scanning by setting the light emission intensity of the light source of each optical scanning unit so that the light intensity of the light spot at the joint C1 (and C2) of the seam of the partial optical scanning area to be inspected is the same. Claim 1) is implemented.

The optical scanning area length of each optical scanning unit is the same, and the optical characteristics of two optical scanning units adjacent to each other are symmetrical with respect to the joint of the adjacent partial optical scanning areas. The deflected light beam is detected outside the effective scanning area by the light receiving element PD1 or the like before the start of light scanning,
The start of optical scanning of each optical scanning unit is synchronized based on the detection on the scanning start side.

The deflection light beam of each optical scanning unit is detected by the light receiving element PD2 or the like after the end of the optical scanning outside the effective scanning area, and a common light receiving element PD2 (and PD3) is used adjacent to the optical scanning unit. The common light receiving element detects a deflected light beam after the end of optical scanning in one optical scanning unit and a light beam before the start of scanning in the other optical scanning unit, and detects a detection time difference between the start of the optical scanning and the end of the optical scanning. , The pixel clock of each optical scanning unit is adjusted.

In the embodiment shown in FIGS. 1 and 3, two optical scanning units are arranged in the main scanning direction. In the embodiment shown in FIGS. 2 and 4, the optical scanning unit arranged in the main scanning direction is used. There are three units.

Hereinafter, the optical scanning modules MA and MB will be described in detail with reference to FIG. FIG. 6 is an exploded perspective view of the optical scanning module. (A) shows the optical scanning module MA, and (b) shows the optical scanning module MB. The optical scanning modules MA and MB have the same configuration except that they are substantially mirror-symmetrical to each other as described above, and the optical elements used are the same. These will be described together.

The optical scanning modules MA and MB have electrode substrates 50A and 50B, middle substrates 60A and 60B, frames 70A and 70B, and sealing plates 80A and 80B.

The electrode substrates 50A and 50B are formed integrally with the rotary axes 5AX and 5BX of the rotary polygon mirror and the lead terminals 51A and 51B.
Through holes HLA and HLB through which AX and 5BX penetrate are formed, light sources 1A and 1B, coupling lenses 2A 'and 2B', and a driving coil CL for driving a rotary polygon mirror.
A, CLB, and are disposed on the electrode substrates 50A, 50B, and penetrate the rotation shafts 5AX, 5BX through the through holes HLA, HLB.

The frames 70A and 70B are composed of folded reflection surfaces ML1A and ML1B and optical path bending reflection surfaces ML2A and ML2.
B and formed on the middle substrates 60A and 60B,
Light sources 1A, 1B, coupling lenses 2A ', 2B',
A space for accommodating the rotating polygon mirrors 5A and 5B fitted with the rotating shaft is formed.

The sealing plates 80A and 80B are formed with windows, and are arranged on the frames 70A and 70B so that the “space” is formed.
Are closed and the windows L are closed, lenses L1A and L1B constituting a part of the scanning image forming optical system are provided, and the deflected light beams reflected by the optical path bending reflection surfaces ML2A and ML2B are passed through the lenses L1A and L1B. It is configured to be injected through

The electrode substrates 50A and 50B are formed by "ceramic molding". Also, the middle substrate 60A,
Reference numeral 60B denotes a silicon substrate on which electrodes and wiring patterns (not shown) are formed by vapor deposition of a metal film, and are connected to the lead terminals 51A and 51B by wire bonding or the like.

The coil portions CLA and CLB for rotatingly driving the rotary polygon mirrors 5A and 5B are also formed by forming a "spiral pattern" as a part of the wiring pattern. In this example, the spiral pattern is formed into three layers by changing the phase in the rotation direction of the rotary polygon mirrors 5A and 5B via an insulating layer such as a nitride film, and applying currents having different phases to form the rotary polygon mirror. It is driving.

The rotary polygon mirrors 5A and 5B are formed by pressing an aluminum plate, each side is mirror-finished, and sleeves 5A1 and 5B1 are inserted into the holes at the center. Plate-shaped annular magnets MGA, MGB are joined to the lower surface so as to face the coil portions CLA, CLB. And
The sleeves 5A1 and 5B1 are engaged with the rotating shafts 5AX and 5BX, and the rotating shafts are supported with a clearance of about several μm. It is also possible to form a dynamic pressure air bearing by providing a herringbone groove inside the sleeve.

In the example of FIG. 6, the semiconductor laser (chip) 1
A, 1B are the middle substrates 60A, 60
B, but since the middle substrates 60A and 60B are silicon substrates, the semiconductor lasers 1A and 1B serving as light sources
Is a direct method using epitaxial technology on a silicon substrate.
It is also possible to deposit an lGaAs layer and form a cladding layer and an active layer that constitute a semiconductor laser.

In fact, the monitoring photodiodes 1a and 1b for detecting the back light of the semiconductor lasers 1A and 1B are formed by directly depositing a GaAs layer on a silicon substrate. The coupling lenses 2A 'and 2B' are mounted separately from the silicon substrate.
It is also possible to form an O ₂ film or the like by directly depositing it on a silicon substrate.

In FIG. 6, reference numerals 61A, 61B, 62
Reference numerals A and 62B denote circuits for controlling current supply to the semiconductor lasers 1A and 1B and the coil portions CLA and CLB, respectively, and are formed directly on the middle substrate.

The frames 70A and 70B are also formed using “single-crystal silicon” as a material, and the folded reflection surfaces ML1A,
The reflection surface shapes of ML1B and the optical path bending reflection surfaces ML2A and ML2B are formed by anisotropic etching.

The sealing plates 80A and 80B are made of a resin material, are provided with a window for taking out a deflected light beam, and are closed by scanning lenses L1A and L1B. The material of the sealing plates 80A and 80B is a transparent resin, and the scanning lenses L1A and L1B can be formed as a part of the sealing plate by photolithography or the like.
A and L1B can be configured as a gradient index lens.

As another embodiment, the window of the sealing plate may be a simple parallel transparent plate. That is, the optical scanning module does not need to include a part of the scanning image forming optical system.

The optical scanning modules MA and MB are provided with a sealing plate 8
Since the inside space is sealed by 0A and 80B, the internal space is kept secret. At this time, the pressure inside the confidential internal space is reduced.
However, the air resistance to the rotation of the rotating polygon mirror can be reduced. Alternatively, "a gas for preventing oxidation such as nitrogen" may be sealed in the internal space in a confidential state to prevent the mirror surface of the rotary polygon mirror from being oxidized.

In the optical scanning device according to the embodiment shown in FIGS. 1 and 3, two optical scanning units are arranged in the main scanning direction, and the optical scanning device according to the embodiment shown in FIGS. In the apparatus, the number of optical scanning units arranged in the main scanning direction is three.
Unit.

The optical scanning module described in the embodiment with reference to FIGS. 5 and 6 deflects a light beam from a light source by rotating a deflecting and reflecting surface of an optical deflector, and scans the deflected light beam. An optical scanning unit that forms one or more light spots on the surface to be scanned by condensing light toward the surface to be scanned by the imaging optical system, and optically scans a part of the surface to be scanned with the light spots;
A plurality of units are arranged in the main scanning direction, and the maximum scanning area is synthetically optically scanned by optical scanning by each optical scanning unit. And the incident direction of the light beam incident on the deflecting / reflecting surface of the corresponding light deflector from the light source side is set to be opposite to each other with respect to the main scanning direction by the adjacent optical scanning unit, and the adjacent light beams are set. In an optical scanning device for performing optical scanning by setting the light emission intensity of the light source of each optical scanning unit, so that the light intensity of the light spot at the joint portion of the partial optical scanning region optically scanned by the scanning unit, An optical scanning module used as a part of each optical scanning unit, having a semiconductor laser or a semiconductor laser array as a light source as a part of each optical scanning unit. Together, at least, it is arranged a coupling lens and an optical deflector is modular, two module MA that is formed in a substantially mirror-symmetrical to each other, M
B are combined and fixedly arranged on the same substrate.

For example, the optical scanning module MA is the optical scanning module according to the twenty-first aspect, and the optical scanning module MB substantially mirror-symmetrical to the optical scanning module MA is the optical scanning module according to the twenty-second aspect.

In the optical scanning modules MA and MB,
The optical deflectors in the module are rotating polygon mirrors 5A and 5B, and the coupling lenses 2A 'and 2B' in the module.
Has a function of forming light beams from the light sources 1A and 1B into substantially parallel light beams in the main scanning direction and forming a long line image in the main scanning direction near the position of the deflecting reflection surface of the optical deflector in the sub-scanning direction. , Lenses L1A and L1 forming a part of the scanning image forming optical system
1B.

The optical scanning modules MA and MB also include light sources 1A and 1B, coupling lenses 2A and 2B for coupling light beams from the light sources to the optical system, optical deflectors 5A and 5B, and scanning image forming. It has lenses L1A and L1B which constitute a part of the optical system, is formed in a housing shape as a whole, and is a folded reflection which directs a light flux emitted from the coupling lens toward a deflecting / reflecting surface of an optical deflector and reflects it back. Plane ML1A,
Lenses L1A and L1B having the ML1B and constituting a part of the scanning image forming optical system are provided so as to close a window provided in the housing.

The optical scanning modules MA and MB used in the optical scanning device shown in FIGS. 3 and 4 are provided with an optical deflector 5A,
5B has optical path bending reflection surfaces ML2A and ML2B that bend the optical path of the deflected light beam deflected by 5B in the direction inclined with respect to the same substrate 10 on which each optical scanning unit is provided.
Instead, the deflected light beam may be emitted from the side surface of the module.

Further, the optical scanning modules MA and MB described in the above embodiments are each provided with a coupling lens 2A ′,
The folded light reflecting surfaces ML1A, M which direct the light beam emitted from B 'to the deflecting reflecting surfaces of the optical deflectors 5A, 5B and reflect back.
L1B and optical path bending reflection surfaces ML2A and ML that bend the optical path of the deflected light beam deflected by the optical deflector in the direction inclined with respect to the same substrate 10 on which each optical scanning unit is provided.
2B, the optical deflector is a rotating polygon mirror, and the coupling lenses 2A 'and 2B' convert the light beam from the light source into a substantially parallel light beam in the main scanning direction and focus the light beam in the sub-scanning direction.
A window provided with a lens L1A and L1B, which has a function of forming an image as a long line image in the main scanning direction in the vicinity of the deflecting reflection surface of the rotary polygon mirror and constitutes a part of the scanning image forming optical system; It is provided so as to close up.

In the optical scanning device described in the embodiment with reference to FIGS. 3 and 4, for example, the semiconductor lasers 1A and 1B are used as light sources disposed in the optical scanning module. It goes without saying that, for example, a semiconductor laser array can be used to optically scan each partial light scanning region by a multi-beam method.

[0174]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As a specific embodiment, an optical scanning device shown in FIG. 3 will be described. Taking the optical scanning unit constituted by the optical scanning module MA and the scanning lens L2A as an example, the semiconductor laser 1A has a light source wavelength of 780 nm. In the semiconductor laser 1A, the position of the light emitting unit is set such that the polarization state of the light beam incident on the deflection reflection surface of the rotary polygon mirror 5A is S-polarized.

The rotary polygon mirror 5A has six deflection reflection surfaces,
Inscribed circle radius: 18mm, SiO on aluminum mirror surface
Is coated with a single layer to an optical thickness of λ / 2 (λ = 780 nm). Both the scanning lenses L1A and L2A are uncoated. The principal ray of the light beam incident on the rotary polygon mirror 5A from the light source side. And the angle formed by the principal ray when the deflected light beam is orthogonal to the scanning line on the surface to be scanned, is set at 60. The light beam from the light source side is transmitted to the rotating polygon mirror 5A with respect to FIG.
At the left side of the figure. Scan lenses L1A, L
The data of 2A is as follows.

The scanning lens L1A has a “coaxial aspherical surface (aspherical surface that is rotationally symmetric with respect to the optical axis)” on both the entrance side and the exit side. As is well known, a coaxial aspherical surface has a coordinate in the optical axis direction x, a coordinate in a direction perpendicular to the optical axis r, a paraxial radius of curvature Rn, and a conic constant Kn, An, Bn, Cn, D
n,. . X = r ^ 2 / [Rn + Rn ・ √ {1- (1 + Kn) r ^ 2 / r ^ 2} + An ・ r ^ 4 + Bn ・ r ^ 6 +
It is represented by Cn · r ^ 8 + Dn · r ^ 10. In this equation, for example, “r ＾ 4” becomes “r
To the fourth power. " The same applies to the following equations. Further, n in Rn, Kn, An, Bn, Cn, Dn and the like is a surface number (n = 1 to 2) of the lens surface of the scanning lens L1A constituting the scanning imaging optical system, counted from the optical deflector side. N = 1 for the entrance surface of the scanning lens L1A, n for the exit surface
= 2). The unit of the dimension having the length dimension is m
m.

Scan lens L1A Incident side surface (n = 1): R1 = -264.0, K1 = 2.449, A1 = 2.594E-07, B1 = 1.256E-1
1, C1 = -2.416E-13, D1 = 4.910E-17 Thickness on optical axis: D = 23.3 Refractive index of material: N = 1.52441 Exit side surface (n = 2): R2 = -61.3, K2 =- 0.0213, A2 = 5.949E-07, B2 = 1.120E-
12, C2 = 2.452E-14, D2 = -3.969E-17 In the above, for example, "5.949E-07" becomes "5.949 to 10-7
Multiplied to the power ". The same applies to the following notation.

The scanning lens L2A has a "non-arc shape in the main scanning direction" on both the incident side surface and the exit side surface. That is, X is the coordinate in the optical axis direction, Y is the coordinate in the main scanning direction in a plane (main scanning section) including the optical axis and parallel to the main scanning direction, and Y is the origin of the optical axis position. The paraxial radius of curvature can be expressed as Rmn, the conic constant as Kmn, and higher-order coefficients as an, bn, cn, dn,.

X = Y ^ 2 / [Rmn + Rmn ・ √ {1- (1 + Kmn) Y ^ 2 / Rmn ^ 2}
+ an ・ Y ^ 4 + bn ・ Y ^ 6 + cn ・ Y ^ 8 + dn ・ Y ^ 10 n in Rmn, Kmn, an, bn, cn, dn, etc. is a scanning lens constituting a scanning imaging optical system. The surface number of the lens surface of L2A counted from the optical deflector side (n = 1 or 2; n = 1 for the entrance surface of scanning lens L2A, n = for the exit surface
2).

A radius of curvature Rns in a plane section (called a sub-scanning section) orthogonal to the main scanning direction can be expressed as follows according to the Y coordinate of the sub-scanning section.

Rns (Y) = RnS + en · Y ^ 2 + fn · Y ^ 4 + gn · Y ^ 6 + hn
Y ^ 8 + in ・ Y ^ 10 + jn ・ Y ^ 12 In the above equation, “RnS” represents the radius of curvature in the sub-scanning section (sub-scanning section including the optical axis) of Y = 0.

Scan lens L2A Incident side surface (n = 1): (shape in main scanning section): Rm1 = -340.0, Km1 = -62.03, a1 = -1.047E-08, b1 = -9.3
02E-12, c1 = -1.271E-15, d1 = 1.863E-19 (shape in sub-scan section): R1S = -32.01, e1 = 1.385E-03, f1 = -4.354E-07, g1 = 2 .
324E-11, h1 = 3.250E-15, I = -2.023E-19, j1 = -6.203E
-23 Thickness on optical axis: D = 3.5 Refractive index of material: N = 1.52441 Exit side surface (n = 2): (shape in main scanning section): Rm2 = -680.0, Km2 = 19.12, a2 = -1.314 E-07, b2 = -2.25
6E-12, c2 = 1.004E-16, d2 = -2.522E-20 (shape in the sub-scanning section): R2S = -16.97, e2 = f2 = g2 = ... = 0 Reflection point on the deflecting reflecting surface Distance between the scanning lens L1A and the incidence side surface: 44.4 mm Distance between the emission side surface of the scanning lens L1A and the incidence side surface of the scanning lens L2A: 50.4 mm Distance between the emission side surface of the scanning lens L2A and the scanned surface: 107.1 m
m As described above, the optical scanning module MC is the same as the optical scanning module MA, the optical scanning module MB is mirror symmetric with the optical scanning module MA, and the incidence on the rotary polygon mirror from the light source side is as shown in FIG. And is the same as the optical scanning module MA except that the processing is performed from the right side of the drawing.

FIG. 7 shows the field curvature of the optical scanning unit having the optical scanning modules MA and MC. As can be seen from the figure, the curvature of field is well corrected in both the main scanning direction and the sub-scanning direction, but the asymmetry due to the influence of the sag of the rotating polygon mirror remains. In the optical scanning unit having the optical scanning module MB, the direction of incidence of the light beam from the light source side to the rotating polygon mirror is:
Since it is opposite to the optical scanning module in the main scanning direction,
The field curvature is obtained by reversing the image plane mirror shown in FIG. 7 in the image height direction.

FIG. 8 shows shading characteristics in the maximum scanning area (partial light scanning area PA + PB + PC).

The partial optical scanning area is the optical scanning module M
Optical scanning is performed with the deflected light beams from A, MB, and MC, respectively. However, since the optical scanning units that optically scan the partial optical scanning areas PA and PC are the same, the shading characteristics are different in the partial optical scanning areas PA and PC. Will be the same.

The optical scanning module used in the optical scanning unit that optically scans the partial optical scanning area PB is mirror-symmetric with the optical scanning modules MA and MC. Therefore, the shading characteristics are the same as those of the partial optical scanning area PA or PC. , The joints between the partial light scanning areas PA and PC and the partial light scanning area PB are symmetrically folded.

The light emission intensity of each semiconductor laser is set so that the light intensity of the light spot for optically scanning each partial light scanning area is made substantially the same at the above-mentioned joint portion. The shading characteristics of the scanning area are
It is good as shown in FIG.

For comparison, three units of the same optical scanning unit using the optical scanning module MA are arranged in the main scanning direction, optical scanning is performed, and the light intensity of the light spot is detected at the joint of each partial optical scanning area. When the emission intensity of each of the semiconductor lasers is set so as to make (substantially) the same, the shading correction of the maximum scanned area is as shown in FIG. A shading difference of approximately 25% is derived from the writing end portion of the partial light scanning area PC. On the other hand, in the above-described embodiment, the fluctuation of the shading characteristics is 10% or less.

In the above description, in all the optical scanning units or optical scanning modules, the rotation directions of the deflecting / reflecting surfaces of the optical deflectors are aligned in the same direction. It may be determined as appropriate for each optical scanning module or for each optical scanning module, and it is not always necessary to make them the same. However, if the rotation direction of each deflecting / reflecting surface is set to the same direction, the “order of pixel information” of the image signal supplied to each optical scanning unit can be the same for all the optical scanning units. The processing of the image information signal is easy.

Finally, an embodiment of the image forming apparatus of the present invention will be described with reference to FIG. In the figure, reference numeral 100 denotes a photoconductive photoconductor as a “photosensitive medium” that forms the actual state of the surface to be scanned described above.
The photoreceptor 100 is formed in a cylindrical shape, and is rotatable in an arrow direction (clockwise).

Around the photosensitive member 100, a charger 111
(A corona discharge type is shown, but the present invention is not limited to this, and a contact type such as a charging roller or a charging brush may be used.), A developing device 115, and a transfer device 117 (a corona discharge type is shown). However, a contact type such as a transfer roller may be used.), And a cleaning device 119 is provided. Further, an optical scanning device 113 is provided, and a charger 111 is provided.
An image is written by optical scanning between the developing device 115 and the ground. In FIG. 10, reference numeral S indicates a sheet-shaped recording medium, and reference numeral 121 indicates a fixing device.

The optical scanning device 113 is of the present invention, and an appropriate one can be selected from those described in the above embodiments and used.

When an image is formed, the photosensitive member 110 is rotated clockwise at a constant speed, and the peripheral surface thereof is uniformly charged by the charger 111. Subsequently, optical scanning is performed by the optical scanning device 113, and an image is written to form an electrostatic latent image. The electrostatic latent image thus formed is a so-called negative latent image, and the image portion is exposed.

The formed electrostatic latent image is reversely developed by the developing device 115 using a magnetic brush developing method, and is visualized as a toner image.

A sheet-like recording medium S such as a transfer sheet or an OHP sheet is conveyed in the direction of the arrow, and a toner image is transferred by a transfer unit 117 in a transfer unit.
At 21, the toner image is fixed and discharged outside the apparatus.

The surface of the photoreceptor 110 after the transfer of the toner image is cleaned by the cleaning device 119 to remove the residual toner and the paper dust, thereby obtaining a clean surface.

That is, the image forming apparatus of the embodiment shown in FIG. 10 forms a latent image by performing optical scanning on the photosensitive surface of the photosensitive medium 100 and visualizes the formed latent image to form an image. 3. The image forming apparatus according to claim 2, wherein the optical scanning device 113 optically scans a photosensitive surface of the photosensitive medium 100.
The optical scanning device according to any one of 0 is used (claim 23), wherein the photosensitive medium 100 is a photoconductive photoconductor, and an electrostatic latent image formed as a latent image is visualized as a toner image. Is done.

[0198]

As described above, according to the present invention, a novel optical scanning method, optical scanning device, optical scanning module, and image forming apparatus can be realized.

As described above, according to the optical scanning method and optical scanning device of the present invention, shading can be effectively reduced in the divided optical scanning system. Further, by using the optical scanning module of the present invention, it is easy to construct an optical scanning device of a divided optical scanning system.

The image forming apparatus of the present invention can easily form a large-area image satisfactorily by using the optical scanning device of the present invention.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining one embodiment of an optical scanning device of the present invention.

FIG. 2 is a diagram for explaining another embodiment of the optical scanning device of the present invention.

FIG. 3 is a diagram for explaining another embodiment of the optical scanning device of the present invention.

FIG. 4 is a diagram for explaining still another embodiment of the optical scanning device of the present invention.

FIG. 5 is a diagram for explaining an optical arrangement in the optical scanning module.

FIG. 6 is a diagram illustrating an example of the structure of the optical scanning module.

FIG. 7 is a diagram illustrating a field curvature of one optical scanning unit in the embodiment.

FIG. 8 is a diagram illustrating shading characteristics in a maximum scanned area according to the embodiment.

FIG. 9 is a diagram illustrating shading characteristics in a maximum scanned area in a comparative example.

FIG. 10 is a diagram illustrating an embodiment of an image forming apparatus.

[Explanation of symbols]

 SUA, SUB Optical scanning unit 5A, 5B 5A, 5B PA, PB Partial optical scanning area C1 Part of the partial scanning area joint 1A, 1B Light source (semiconductor laser)

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 2C362 AA03 AA13 AA14 AA26 AA42 AA43 AA52 AA53 AA54 AA56 AA63 BA49 BA67 BA83 BA84 BA90 DA03 DA12 2H045 AA01 BA22 BA23 BA36 CA63 CA89 CB22 CB42 DA02 DA04 DA41

Claims (23)

[Claims] 1. A light beam from a light source is deflected by rotation of a deflecting / reflecting surface of an optical deflector, and the deflected light beam is condensed toward a surface to be scanned by a scanning image forming optical system and is converged on the surface to be scanned. 1 in
A plurality of optical scanning units for forming the above light spots and optically scanning a part of the surface to be scanned by the light spots are arranged in the main scanning direction. In the optical scanning method of performing optical scanning synthetically, at least from the light source to the optical deflector of the all-optical scanning unit is arranged on the same substrate, and the light is incident on the deflection reflecting surface of the corresponding optical deflector from the light source side. The incident direction of the light beam is set to be opposite to each other with respect to the main scanning direction in the adjacent optical scanning unit, and the light intensity of the light spot at the joint of the partial optical scanning region optically scanned by the adjacent optical scanning unit is adjusted. An optical scanning method, wherein the optical scanning is performed by setting the emission intensity of the light source of each optical scanning unit so as to be the same. 2. A light beam from a light source is deflected by rotation of a deflecting / reflecting surface of an optical deflector, and the deflected light beam is condensed toward a surface to be scanned by a scanning image forming optical system and is converged on the surface to be scanned. 1 in
A plurality of optical scanning units for forming the above light spots and optically scanning a part of the surface to be scanned by the light spots are arranged in the main scanning direction. An optical scanning device that performs synthetic optical scanning on the same substrate, wherein at least from the light source to the optical deflector of the all-optical scanning unit is arranged on the same substrate, and the deflecting / reflecting surface of the corresponding optical deflector from the light source side The incident direction of the luminous flux incident on the optical scanning unit is set to be opposite to each other with respect to the main scanning direction in the adjacent optical scanning unit, and the light at the joint portion of the partial optical scanning region optically scanned by the adjacent optical scanning unit An optical scanning device, wherein the light emission intensity of a light source of each optical scanning unit is set so that the light intensity of a spot is the same. 3. The optical scanning device according to claim 2, wherein each optical scanning unit has the same optical scanning region length. 4. The optical scanning device according to claim 3, wherein the optical characteristics of the two optical scanning units adjacent to each other are symmetric with respect to the joint of the adjacent partial optical scanning regions. apparatus. 5. An optical scanning device according to claim 2, further comprising a light receiving element for detecting a deflected light beam of each optical scanning unit outside the effective scanning area before the start of optical scanning. Scanning device. 6. The optical scanning device according to claim 5, further comprising a light receiving element for detecting a deflected light beam of each optical scanning unit outside the effective scanning area after the completion of the optical scanning. 7. An optical scanning device according to claim 6, wherein a common light receiving element is used in an adjacent portion of the optical scanning unit, and the common light receiving element allows the deflection light beam after the light scanning in one of the optical scanning units to be completed. An optical scanning device for detecting a light beam before scanning in the other optical scanning unit. 8. The optical scanning device according to claim 2, wherein the light source of each optical scanning unit is a semiconductor laser or a semiconductor laser array, and the light source of each optical scanning unit is used to scan and form an optical system. An optical scanning device characterized by being arranged on the same substrate. 9. The optical scanning device according to claim 8, wherein: a light receiving element for detecting the deflection light beam of each optical scanning unit before the start of the optical scanning;
An optical scanning device which is arranged on the same substrate. 10. The optical scanning device according to claim 9, wherein the light receiving elements arranged between the optical scanning units are shared by the optical scanning units on both sides thereof. 11. The optical scanning device according to claim 2, wherein at least a part of the scanning image forming optical system in each optical scanning unit is not arranged on the same substrate. Optical scanning device. 12. The optical scanning device according to claim 11, wherein the scanning image forming optical system in each optical scanning unit is constituted by two lenses, and in each optical scanning unit, the light source side of the scanning image forming optical system from the light source. An optical scanning device characterized in that the lenses up to are arranged on the same substrate. 13. An optical scanning apparatus according to claim 12, wherein each of said optical scanning units comprises a scanning image forming optical system.
An optical scanning device, wherein, of the plurality of lenses, the lens not arranged on the same substrate is arranged and integrated in the main scanning direction. 14. The optical scanning device according to claim 11, wherein a light source of the optical scanning unit is a semiconductor laser or a semiconductor laser array, and a portion of each optical scanning unit disposed on the same substrate is:
An optical scanning device, wherein each optical scanning module is modularized as an optical scanning module, and each optical scanning module is fixedly arranged on the same substrate. 15. The optical scanning device according to claim 14, wherein the optical scanning module includes two types of modules having structures substantially mirror-symmetric to each other, and these two types of optical scanning modules are alternately arranged in the main scanning direction. An optical scanning device, wherein: 16. An optical scanning device according to claim 15, wherein at least two light sources, a coupling lens, and an optical deflector are integrally disposed in the two types of optical scanning modules having structures substantially mirror-symmetric to each other. An optical scanning device characterized by being performed. 17. An optical scanning device according to claim 15, wherein each of the two types of optical scanning modules having a structure substantially mirror-symmetrical to each other comprises a light source and a cup for coupling a light beam from the light source to an optical system thereafter. An optical scanning device, comprising: a ring lens, an optical deflector, and a lens that constitutes a part of a scanning image forming optical system, wherein the entirety is formed in a housing shape. 18. An optical scanning device according to claim 17, wherein each optical scanning module has a folded reflecting surface for directing a light beam emitted from the coupling lens to a deflecting reflecting surface of the optical deflector and for reflecting the light flux back. Optical scanning device characterized by the following. 19. The optical scanning device according to claim 17, wherein a lens constituting a part of the scanning image forming optical system of each optical scanning module is provided so as to close a window provided in the housing. An optical scanning device, comprising: 20. An optical scanning device according to claim 17, wherein each optical scanning module passes an optical path of a deflected light beam deflected by an optical deflector to the same substrate on which each optical scanning unit is provided. An optical scanning device having an optical path bending reflection surface that bends in a tilting direction. 21. A light beam from a light source is deflected by rotation of a deflecting / reflecting surface of an optical deflector, and the deflected light beam is condensed toward a surface to be scanned by a scanning image forming optical system and is converged on the surface to be scanned. A plurality of optical scanning units are formed in the main scanning direction for forming one or more light spots and optically scanning a part of the surface to be scanned by the light spots. Optical scanning of the scanning area is performed synthetically, and at least the light source to the optical deflector of the all-optical scanning unit are arranged on the same substrate, and the light is incident on the deflection reflecting surface of the corresponding optical deflector from the light source side. The incident direction of the light beam is set so as to be opposite to each other with respect to the main scanning direction in the adjacent optical scanning unit, and the light of the light spot at the joint of the partial optical scanning area optically scanned by the adjacent optical scanning unit An optical scanning device used as a part of each optical scanning unit in an optical scanning device that performs optical scanning by setting the light emission intensity of the light source of each optical scanning unit so that the optical scanning unit has the same degree. As a part of the unit, a semiconductor laser or a semiconductor laser array is used as a light source, and at least a coupling lens and an optical deflector are arranged to form a module, and two types of modules that are formed substantially mirror-symmetric with each other are combined. An optical scanning module that is fixedly arranged on the same substrate and constitutes one of the two types of modules. 22. An optical scanning module formed substantially mirror-symmetric with respect to the optical scanning module according to claim 21. 23. An image forming apparatus which forms a latent image by optically scanning a photosensitive surface of a photosensitive medium to form a latent image, and optically scans the photosensitive surface of the photosensitive medium. An image forming apparatus using the optical scanning device according to any one of claims 2 to 20 as an apparatus.