JP3387805B2 - Scanning optical system and image forming apparatus using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning optical system and an image forming apparatus using the scanning optical system, and in particular, it is possible to reduce focus deviation and scanning position deviation by appropriately performing temperature compensation in the scanning optical system. is there.

[0002]

2. Description of the Related Art FIG. 7 is a sectional view (sub-scanning sectional view) of a main part of a conventional scanning optical system using a single light beam in the sub-scanning direction. FIG. 8 is a schematic view of a main part showing a refractive power arrangement in the sub-scanning direction of a multi-beam scanning optical system using a plurality of light beams.

In FIG. 7, a light beam (laser light) emitted from a laser light source 71 is converted into a substantially parallel light beam (collimator light) by a collimator lens 72, and a cylinder lens group 73 having a predetermined refractive power in the sub-scanning direction. Incident on
The cylinder lens group 73 focuses the light at a deflection point P near the deflection surface of an optical deflector 74 composed of a polygon mirror. The light beam deflected and reflected by the deflecting surface is condensed on the surface to be scanned 76 by the fθ lens 75 having the fθ characteristic, and the surface to be scanned 76 is optically scanned with the light beam to record an image. . The deflection point P and the condensing point Q on the surface to be scanned in the figure are in an optically conjugate relationship with the fθ lens 75 in the sub-scan section.

A method of once focusing the light beam in the vicinity of the deflecting surface of the optical deflector 74 and then forming an image on the surface to be scanned 76 is called a re-imaging scanning system or a tilt correction scanning system. It is a technology. Further, the fθ lens 75 in the figure is composed of a toric lens having different powers in the main scanning direction and the sub scanning direction.

In recent years, some or all of the fθ lenses have been made of resin (made of plastic) for cost reduction.
The technology to do so is being established. At this time, the problem is that the resin lens has a large temperature dependency of the refractive index, so that the focus position is displaced even when the temperature inside the apparatus is increased. For example, with an acrylic fθ lens with an fθ characteristic of 243 (mm) and an imaging magnification of 2.5 times, a temperature rise of 25 ° C. will result in about 5.2 (mm)
The focus position shifts, and the condensing point Q on the surface to be scanned 76 moves to the condensing point Q ′ as shown in FIG. 7.

As a method of correcting this, for example, FIG.
As shown in FIG. 3, the cylinder lens group 73 is made up of the first cylinder lens 7 made of glass with a small positive refractive power fluctuation.
3a and the second cylinder lens 73b made of negative power plastic (acrylic or the like).

That is, the focal length of the cylinder lens group 73 is set to be shortened by about 0.83 (mm) by raising the temperature, and the converging point P is shifted to the converging point P'after raising the temperature. Therefore, the focus Q is maintained without changing the image plane focus before and after the temperature rise.

On the other hand, due to the increasing need for higher image quality,
As the laser spot becomes smaller and the depth at which the desired spot diameter is obtained (depth of focus) becomes narrower, even when the fθ lens is made of only glass material, fluctuations in the refractive index of glass (temperature rise of glass and wavelength of laser light source) Focus fluctuation due to shift) is also a problem.

A method for correcting this is, for example, the second cylinder lens 73 of the cylinder lens group 73.
Not only the plastic lens but also the glass lens b may be optimized by appropriately combining the refractive index characteristics.

Further, as a method of correcting the focus variation, for example, a combination of glass materials of the lens structure of the collimator lens 72 is set to be optimum to intentionally generate chromatic aberration,
It is also possible to compensate for focus fluctuations of the entire system.

In FIG. 8, two light beams emitted from _two light emitting portions (light emitting points) S ₁ and S ₂ constituting the multi-semiconductor laser 81 are converted by a collimator lens 82 into a substantially parallel light beam, and the sub-scanning direction. Then, the light is incident on a cylinder lens group 83 having a predetermined refracting power, and the cylinder lens group 83 focuses the light on deflection points P ₁ and P ₂ near the deflection surface of an optical deflector 84 composed of a polygon mirror. Then, the two light beams deflected by the optical deflector 84 are condensed by the fθ lens 85 having the fθ characteristic at two converging points (exposure positions) Q ₁ and Q ₂ on the surface 86 to be scanned, and the condensate is scanned. Face 86
An image is recorded by scanning the upper part with two light beams at the same time.

In such a multi-beam scanning optical system, two laser spots Q ₁ and Q on the surface to be scanned are provided.
The interval of _{2 in} the sub-scanning direction (scan line interval) varies depending on the specifications of the main body of the device, for example, resolution 600 DPI (dot / inch)
Then, it will be set to 42.3 μm. At this time, the distance between the _two light emitting portions S ₁ and S _{2 in} the sub-scanning direction (light emitting point distance)
Is about 8 μm (focal length of the collimator lens 82 f _CO =
25 (mm), focal length f _CL = 5 of the cylinder lens group 83
5 (mm), fθ lens 85 magnification in the sub-scanning direction β = 2.5
Must be).

However, when the two light emitting portions S ₁ and S ₂ are brought close to each other, mutual interference (thermal and electrical crosstalk) becomes large, which makes practical application difficult. Therefore, when a laser chip is manufactured with the distance between the _two light emitting portions S ₁ and S _{2 set to} a distance of 60 to 200 μm and mounted on the scanning optical system,
A method of mounting the line connecting the _two light emitting portions S ₁ and S ₂ with a predetermined tilt with respect to the scanning surface is disclosed in, for example, Japanese Examined Patent Publication No.
Proposed in the issue.

[0014]

The above-mentioned conventional multi-beam scanning optical system has the following various problems.

A multi-semiconductor laser is applied as a laser light source to a scanning optical system having a temperature compensation system as shown in FIG. 7, and a scanning optical system is formed so as to connect a plurality of laser spots in the sub-scanning direction as shown in FIG. With this configuration, the focus is compensated in accordance with the temperature rise inside the machine, and no focus shift occurs.

However, since the power arrangement of the scanning optical system is different before and after the temperature rise, there is a problem that the magnification relationship in the sub-scanning direction is broken and the scanning line interval is changed during the temperature rise.

For example, in FIG. 7, at room temperature, the focal length f _CO of the collimator lens 72 is 17 (mm), the focal length f of the cylinder lens group 73 is f _CL = 58.0 (mm), and the fθ characteristic is 24.
3 (mm), fθ lens 75 sub-scanning direction magnification β = 2.5
When it is set to 00 times and a scanning line interval of 42.3 μm is achieved, for example, at + 25 ° C. (temperature rise), about 5.
To correct the focus variation of 2 (mm) at a cylinder lens 73, the focal length of the cylinder lens 73 is _f'CL
= 57.17 (mm), the magnification of the fθ lens 75 in the sub-scanning direction is β ′ = 2.479, and as a result, the scanning line interval is 4
There is a problem that it fluctuates to 1.37 μm (Δ2.3%).

In order to solve the above-mentioned problems, the present invention provides a holding means that allows the laser light source to rotate around the optical axis in accordance with environmental changes (temperature changes) of the scanning optical system. Compensating for changes in the scanning line spacing in the sub-scanning direction that occur when the magnification relationship of the system changes, so that stable optical performance can always be achieved regardless of environmental changes, and the stability of device quality is improved. It is an object of the present invention to provide a scanning optical system capable of performing the above and an image forming apparatus using the same.

[0019]

A scanning light according to the first aspect of the present invention.
The academic system guides a plurality of light beams emitted from a laser light source having a plurality of light emitting units to a deflecting unit, and causes the plurality of light beams deflected and reflected by the deflecting unit to pass through a scanning lens system on a surface to be scanned. To the scanning surface and scan the surface to be scanned with multiple light beams
In the scanning optical system, the holding means is provided so that the laser light source can rotate around the optical axis according to the environmental change of the scanning optical system, and the holding means holds the laser light source.
Laser holding part and a housing for fitting with the laser holding part
And a material of the laser holding portion and the housing
Have different linear expansion coefficients from each other.
And a rotation restricting portion that relatively restricts the housing
It is characterized in that was.

According to a second aspect of the present invention, there is provided a scanning optical system in which a plurality of light beams emitted from a laser light source having a plurality of light emitting portions are deflected via a first optical system including a resin lens having a negative refractive power. On the surface to be scanned through the second optical system including a resin lens having a positive refractive power, and the plurality of light beams deflected and reflected by the deflecting means are guided to the surface to be scanned. in the scanning optical system for scanning a plurality of light beams, in response to environmental changes of the scanning optical system, the said holding means is provided with retaining means such as the laser light source is rotatable about the optical axis the
A laser holding part for holding a laser light source, and the laser holding part.
A laser holding part having a housing fitted with a holding part,
And the linear expansion coefficient of the material of the housing are different from each other.
The laser holder and the housing relative to each other.
It is characterized by the provision of a rotation restricting portion that controls the rotation .

The invention of claim 3 is the invention of claim 1 or 2.
The holding means holds the laser light source.
Laser holding portion and a housing fitted with the laser holding portion
Of the material of the laser holding portion and the housing.
The linear expansion coefficients are different from each other, and
The rotation restricting part that relatively restricts the housing is a bulk
A bulk material, and the bulk material is a bar protruding from the housing.
Of the bulk material stay and the bulk material receiving portion of the laser holding portion
Sandwiched between them, the coefficient of linear expansion of the material of the bulk material is
It is characterized by being larger than the linear expansion coefficient of the material of the housing.
is doing. The invention of claim 4 is the same as the invention of claim 1 or 2.
In addition, the rotation restricting portion has a fitted long hole and a boss.
And the boss is attached to the housing
Is characterized by.

A scanning optical system according to a fifth aspect of the present invention is a scanning optical system having a laser light source having a plurality of light emitting portions,
Depending on the environmental fluctuations of the scanning optical system is provided with a retaining means such as the laser light source is rotatable about the optical axis, the holding hands
The stage includes a laser holding portion for holding the laser light source and the laser holding portion.
Laser holding unit and a housing fitted with the laser holding unit.
The linear expansion coefficients of the materials of the holding part and the housing are different from each other.
The laser holding part and the housing
It is characterized by the provision of a rotation restricting portion for restricting it selectively .

According to a sixth aspect of the present invention, there is provided a scanning optical system in which a plurality of light sources are provided.
A scanning optical system having a laser light source having a light section,
According to the environmental change of the scanning optical system, the laser light source
The holding means is provided so as to be rotatable around the holding hand.
The stage includes a laser holding portion for holding the laser light source and the laser holding portion.
Laser holding unit and a housing fitted with the laser holding unit.
The linear expansion coefficients of the materials of the holding part and the housing are different from each other.
The laser holding part and the housing
The rotation restricting portion that restricts the bulk material has a bulk material.
Is the bulk material stay protruding from the housing and the
It is sandwiched between the bulk material receiving part of the zipper holding part,
The coefficient of linear expansion of the material of the bulk material is the linear expansion coefficient of the material of the housing.
It is characterized by a larger expansion coefficient .

The invention of claim 7 is the same as the invention of claim 5 or 6.
Where the scanning optical system is at least one resin lens
It is characterized by having. The invention of claim 8 is a claim
In the invention of Item 5, the rotation restricting portion is an elongated hole fitted
And a boss, the boss being attached to the housing.
It is characterized by being. Image of the invention of claim 9
The forming device according to any one of claims 1 to 8.
The feature is that the scanning optical system is used in the image forming apparatus.
It

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view of a main part of the first embodiment when the present invention is used in an image forming apparatus such as a laser beam printer, and FIG. 2 is a refraction in a sub-scanning direction in the first embodiment of the present invention. It is a principal part schematic diagram which shows force arrangement.

In the figure, 1 is a plurality of light emitting portions (light emitting points) S ₁ ,
It is a laser light source having S ₂ , and is composed of, for example, a multi-semiconductor laser. The multi-semiconductor laser 1 according to the present embodiment is held by a holding unit described later so as to be rotatable about the optical axis according to environmental changes (temperature changes) of the scanning optical system (this apparatus).

A collimator lens 2 converts a plurality of light beams (light beams) emitted from the multi-semiconductor laser 1 into substantially parallel light beams.

Reference numeral 3 denotes a cylinder lens group as a first optical system, which is a glass first cylinder lens 3a having a positive refractive power (power) in the sub-scanning direction and having a small refractive index variation, and a sub-scanning direction. Has a second cylinder lens (resin lens) 3b made of plastic (acryl or the like) having a negative refractive power (power), and a plurality of substantially parallel light beams converted by the collimator lens 2 will be described later. The light is focused and incident on the deflection points P1 and P2 on the deflection surface 4a of the optical deflector 4.

Reference numeral 4 denotes an optical deflector as a deflecting means, which is composed of, for example, a polygon mirror, and is rotated at a predetermined speed by a driving means (not shown) such as a motor.

Reference numeral 5 denotes a scanning lens system as a second optical system, which is a single plastic fθ having a positive refractive power.
A plurality of light beams, each of which is composed of a lens (resin lens) and is deflected by the optical deflector 4 based on the image information, is formed on the surface of the photosensitive drum 6 as a surface to be scanned. The fθ lens 5 makes the deflection surface 4a of the optical deflector 4 and the photosensitive drum surface 6 conjugate with each other in the sub-scanning plane. Although the scanning lens system 5 is composed of one lens in this embodiment, it may be composed of a plurality of lenses. In addition, it is not essential to include a plastic lens, and for example, it may be configured by only a glass lens.

In this embodiment, a plurality of (two in this embodiment) light beams emitted from the multi-semiconductor laser 1 are converted into substantially parallel light flux (collimator light) by the collimator lens 2 and are incident on the cylinder lens group 3. is doing. The cylinder lens group 3 emits a substantially parallel light flux in the main scanning cross section of the incident substantially parallel light flux,
Converging in the sub-scan section, the deflecting surface 4 of the optical deflector 4 is converged.
They are formed as substantially line images at the deflection points P ₁ and P ₂ of a, respectively. Then, the plurality of light beams deflected by the deflecting surface 4a of the optical deflector 4 pass through the fθ lens 5 so that the scanning linearity thereof is corrected and the condensing point Q on the photosensitive drum surface 6 as the surface to be scanned. ₁ and Q ₂ are imaged respectively and linearly move at a substantially constant velocity, and the photosensitive drum surface 6 is optically scanned with the plurality of light beams at the same time. As a result, an image is recorded on the photosensitive drum surface 6 as a recording medium.

Next, temperature compensation of the scanning optical system in this embodiment will be described. The specifications at room temperature in this embodiment are as follows: Focal length f _CO of the collimator lens 2 = 17 (mm) Focal length of the cylinder lens group f _CL = 58.00 (mm) f θ characteristic of the fθ lens 5 f = 243 ( mm) fθ The sub-scanning magnification β of the lens 5 is β = 2.500.

As described above, the laser light source 1 uses a multi-semiconductor laser having two light emitting points on one chip. The specifications are as follows: oscillation wavelength λ = 680 nm ± 15 nm (relative difference 5 nm or less) light emitting point Interval L = 0.080 (nm) ± 5 nm θ ∥ (parallel) = 9 ° ± 4 ° (relative difference 2 ° or less) θ ⊥ (vertical) = 28 ° ± 10 ° (relative difference 5 ° or less) AS = 25 μm The following (relative difference is 10 μm or less).

In this embodiment, the fθ lens 5 is formed of a resin lens (plastic lens) as described above.
This resin lens has a large temperature dependency of the refractive index, and there is a problem that the focus position is displaced even when the temperature inside the apparatus is increased. For example, in the case of an acrylic fθ lens, the focus position is shifted by about 5.2 (mm) when the temperature is raised by + 25 ° C. In order to correct this, in the present embodiment, as described above, the cylinder lens group 3 is made of the first glass made of glass having positive power and small fluctuation in refractive index.
And a second cylinder lens 3b made of plastic having negative power.

That is, in this embodiment, the power arrangement is set so that the focal length of the cylinder lens group 3 is shortened by about 0.83 (mm) due to the temperature rise. As a result, the focus variation is canceled by the cylinder lens group 3 and the fθ lens 5, and the focus position on the scanned surface 6 does not vary regardless of the environmental variation (temperature variation).

The interval (scan line interval) between the two laser spots on the surface to be scanned in the sub-scanning direction differs depending on the specifications of the apparatus main body, for example, a resolution of 600 DPI (dot / inch).
Then, it will be set to 42.3 μm. At this time, the distance between the two light emitting portions in the sub-scanning direction needs to be about 4.96 μm.

Since the distance between the two light emitting portions of the multi-semiconductor laser is required to be about 80 μm, the line connecting the two light emitting portions should be tilted at an angle θ ₁ = about 3.56 ° with respect to the scanning plane when the multi semiconductor laser is mounted on the scanning optical system. Can be assembled.

On the other hand, when the temperature is raised, the magnification relationship in the sub-scanning direction is lost as described above, and the scanning line spacing in the sub-scanning direction changes.

The focal length _f'CL = 57.17 focal length _f'CO = 17 (mm) cylindrical lens group 3 at this time + 25 ° C. subscanning direction power arrangement after heating the collimator lens 2 (mm) The sub-scanning magnification β ′ of the fθ lens 5 is 2.479.

Therefore, in the present embodiment, when the temperature of the multi-semiconductor laser 1 is raised by the holding means so that the multi-semiconductor laser 1 can be rotated around the optical axis according to the temperature rise (for example, + 25 ° C. rise).
The line connecting the two light emitting parts is set so that the angle θ ₂ = about 0.08 ° with respect to the scanning plane, and the total (θ ₁ + θ ₂ )
The angle θ _{SUM is} about 3.64 °. As a result, the scanning line interval in the sub-scanning direction on the surface to be scanned 6 can be maintained at 42.3 μm even after the temperature is raised.

In this embodiment, even if the fθ lens 5 and the cylinder lens group 3 do not include a resin lens (plastic lens), that is, even if the fθ lens 5 is composed of only a glass lens, the fluctuation of the refractive index of the glass lens (glass When the focus fluctuation due to the temperature rise and the wavelength shift of the laser light source) is also a problem, as a method for correcting this, for example, the cylinder lens group 3 is not limited to the plastic lens, and the refractive index characteristics including the glass lens are appropriate. It may be configured in combination with.

FIGS. 3 and 4 are schematic views of the main part of the peripheral portion of the multi-semiconductor laser according to the present embodiment, and the multi-semiconductor laser can be rotated around the optical axis according to environmental changes (temperature changes). As shown in FIG. 3 and 4, the same elements as those shown in FIG. 1 are designated by the same reference numerals.

In the figure, 14 is a laser mount (laser
It is a holding part) and the multi-semiconductor laser 1 is press-fitted therein. Reference numeral 15 denotes a scanning system unit housing (hereinafter also referred to as “housing”), which is fitted with the laser mount 14. In this embodiment, the materials of the laser mount 14 and the housing 15 are made to have different linear expansion coefficients.

Reference numeral 16 denotes a bulk material as a rotation restricting portion for relatively restricting the laser mount 14 and the housing 15, and the bulk material stay 1 protruding from the housing 15
7 and the bulk material receiving portion 41 of the laser mount 14, and is provided in a region other than the scanning surface of the optical deflector.

Reference numeral 21 is a collimator lens barrel. Element 1
4, 15, 16, 17, 41, etc. constitute one element of the holding means.

In this embodiment, the laser mount 1
The multi-semiconductor laser 1 is press-fitted into the lens 4, and a collimator lens barrel 21 is connected to the tip. This connection method is a well-known technique from the past, and it has a bimetal structure, and it is changed in accordance with environmental changes (temperature changes). The focus shift due to the chromatic aberration between the laser light source wavelength and the collimator lens 2, the collimator This prevents occurrence of focus shift and the like caused by displacement of the collimator lens 2 due to expansion of the lens barrel 21 and the laser mount 14.

The laser mount 14 is fitted in the fitting hole 31 of the housing 15 and is rotatable about the optical axis X. The bulk material 16 is sandwiched between the bulk material stay 17 protruding from the housing 15 and the bulk material receiving portion 41 of the laser mount 14 as described above, and the linear expansion coefficient of the material is the linear expansion of the material of the housing 15. It is set to be larger than the coefficient. As a result, when the environmental temperature rises, the bulk material 16 expands in the direction of arrow A shown in FIG. 4 as compared with the housing 15, and pushes up the bulk material receiving portion 41. Since the laser mount 14 is provided so as to be rotatable with respect to the housing 15, the laser mount 14 is rotated in the direction of the arrow B shown in FIG. 4, whereby the multi-semiconductor laser 1 is rotated about the optical axis X, and the multi-semiconductor laser 1 is rotated. The inclination of the line connecting the two light emitting portions (not shown) of the semiconductor laser 1 differs before and after the temperature rise with respect to the horizontal axis (main scanning direction) Y.

As described above, in this embodiment, the focus variation due to the environmental variation (temperature variation) of the scanning optical system is compensated as described above, and the multi-semiconductor laser 1 can be rotated around the optical axis according to the environmental variation. By providing such holding means, it is possible to compensate for a change in the scanning line interval in the sub-scanning direction that occurs when the magnification relationship of the entire system changes.

FIGS. 5 and 6 are schematic views of the main part of the peripheral portion of the multi-semiconductor laser according to the second embodiment when the present invention is used in an image forming apparatus such as a laser beam printer, and FIG. At room temperature, FIG. 6 shows the state when the temperature of the apparatus is raised. 5 and 6, the same elements as those shown in FIGS. 3 and 4 are designated by the same reference numerals.

The present embodiment differs from the first embodiment described above in that the rotation restricting portion is replaced by a bulk material, and an elongated hole and a boss are used, and the rotation of the laser mount is changed in accordance with the temperature change. That is, the laser is configured to be rotatable around the optical axis. Other configurations and optical actions are substantially the same as those of the first embodiment, and similar effects are obtained.

That is, in the figure, reference numeral 20 is a rotation restricting portion, which has a long hole 18 and a boss 19 fitted therein, and is provided in a region other than the scanning surface by the optical deflector.

Here, the coordinate systems X, Y and Z are set as shown in FIGS. The Y axis is provided on the scanning surface of the optical deflector. The boss 19 is attached to the housing 15 at a height Z ₀ from the Y axis. Slot 18 and boss 1
9 is fitted in the Z-axis direction, and the major axis of the elongated hole 18 is substantially parallel to the Y-axis.

The elements 14, 15, 18, 19 and the like constitute one element of the holding means.

Now, the linear expansion coefficients of the materials of the laser mount 14 and the housing 15 are η ₁ and η ₂ , respectively, and η ₁
<Η ₂ is set.

FIG. 6 shows the case where the environmental temperature rises (ΔT> 0). When the time (height from the Y-axis and the Y'-axis to the boss) parameters shown in FIG. 6 height from Z _1, Z ₂ is Y-axis at the normal temperature of 5 to the boss and the Z _0, Z ₁ = Z ₀ (1 + ΔT × η ₁ ) Z ₂ = Z ₀ (1 + ΔT × η ₂ ). Since Z ₁ <Z ₂ (η ₁ <η ₂ ) here, the laser mount 14 is tilted by an angle Δθ with respect to the Y axis when the temperature is raised.

The position of the boss 19 at room temperature is (Y, Z) =
If (Y ₀ , Z ₀ ), the angle Δθ is

[0057]

[Equation 1] Can be found at.

As a result, when the temperature is raised (ΔT> 0), the multi-semiconductor laser 1 rotates about the optical axis X (perpendicular to the Y and Z axes) by Δθ, and the two semiconductor lasers 1 emit two lights. The inclination of the line connecting the portions (not shown) differs before and after the temperature rise with respect to the Y axis (main scanning direction).

As described above, in this embodiment, the focus fluctuation due to the environmental fluctuation (temperature change) of the scanning optical system is compensated as described above, and the multi-semiconductor laser 1 can be rotated around the optical axis according to the environmental fluctuation. By providing such holding means, it is possible to compensate for a change in the scanning line interval in the sub-scanning direction that occurs when the magnification relationship of the entire system changes.

[0060]

As described above, the present invention compensates the focus variation due to the environmental variation (temperature variation) of the scanning optical system, and holds the laser light source so that it can rotate around the optical axis in accordance with the environmental variation. By providing the means, it is possible to compensate for the change in the scanning line interval in the sub-scanning direction that occurs when the magnification relationship of the entire system changes, and thereby always exhibiting stable optical performance regardless of environmental changes, A scanning optical system and an image forming apparatus using the scanning optical system that can improve the stability of the quality of the apparatus can be achieved.

[Brief description of drawings]

FIG. 1 is a schematic view of a main part of a first embodiment when the present invention is used in an image forming apparatus.

FIG. 2 is a schematic view of a main part showing a refracting power arrangement in a sub-scanning direction according to the first embodiment of the present invention.

FIG. 3 is a schematic view of a main part showing a peripheral part of the laser light source according to the first embodiment of the present invention.

FIG. 4 is a schematic view of a main part showing a peripheral part of the laser light source according to the first embodiment of the present invention.

FIG. 5 is a schematic view of a main part showing a peripheral part of a laser light source according to a second embodiment of the present invention.

FIG. 6 is a schematic view of a main part showing a peripheral portion of a laser light source according to a second embodiment of the present invention.

FIG. 7 is a schematic view of a main part of a conventional scanning optical system.

FIG. 8 is a schematic view of a main part of a conventional multi-beam scanning optical system.

[Explanation of symbols]

1 Laser light source (multi-semiconductor laser) 2 Collimator lens 3 First optical system (cylinder lens group) 3a First cylinder lens 3b Second cylinder lens 4 Deflection means (optical deflector) 5 Second optical system (scanning lens system) 6 Scanned surface (photosensitive drum surface) 14 Laser mount 15 housing 16 Bulk material 18 slots 19 Boss

Claims (9)

(57) [Claims] 1. A surface to be scanned is guided through a scanning lens system by guiding a plurality of light beams emitted from a laser light source having a plurality of light emitting sections to a deflecting means and deflecting and reflecting the plurality of light beams by the deflecting means. Light beams are guided upward and a plurality of light beams are emitted on the scanned surface.
In the scanning optical system for scanning, depending on environmental changes of the scanning optical system, said holding means is provided a holding means such as the laser light source is rotatable about the optical axis
Is a laser holding portion for holding the laser light source, and the laser
-Has a housing that fits with the holding part,
The linear expansion coefficients of the materials of the holding part and the housing are different from each other.
The laser holding portion and the housing relative to each other.
A scanning optical system characterized in that a rotation restricting portion for restricting the rotation is provided . 2. A plurality of light beams emitted from a laser light source having a plurality of light emitting portions are guided to a deflecting means via a first optical system including a resin lens having a negative refractive power, and the deflecting means A plurality of deflected and reflected light beams are guided to a surface to be scanned through a second optical system including a resin lens having a positive refractive power, and the surface to be scanned is scanned with the plurality of light beams. in <br/>査光science-based, depending on environmental changes of the scanning optical system, said holding means is provided a holding means such as the laser light source is rotatable about the optical axis
Is a laser holding portion for holding the laser light source, and the laser
-Has a housing that fits with the holding part,
The linear expansion coefficients of the materials of the holding part and the housing are different from each other.
The laser holding portion and the housing relative to each other.
A scanning optical system characterized in that a rotation restricting portion for restricting the rotation is provided . Wherein said holding means comprises a laser holder for holding the laser light source, and a housing for mating with the laser holder, the linear expansion coefficient of the material of the said laser holder and the housing are mutually The laser protection is different
The rotation restricting portion that relatively restricts the holding portion and the housing has a bulk material, and the bulk material is sandwiched between the bulk material stay protruding from the housing and the bulk material receiving portion of the laser holding portion. The scanning optical system according to claim 1 or 2, wherein the material of the bulk material has a coefficient of linear expansion larger than that of the material of the housing. 4. and a said rotation regulating portion mated long hole and the boss, claim 1 or 2 of the scanning optical system the boss is characterized in that attached to the housing. 5. A scanning optical system having a laser light source having a plurality of light emitting units, wherein the laser light source is rotatable about an optical axis in accordance with environmental changes of the scanning optical system. And a holding means for holding the laser light source.
And a housing fitted with the laser holding portion,
Linear expansion coefficient of material of the laser holding part and the housing
Are different from each other, and the laser holder and the housing
A scanning optical system characterized in that a rotation restricting portion for relatively restricting the movement is provided . 6. A laser light source having a plurality of light emitting parts.
A scanning optical system , wherein the laser light source has an optical axis according to environmental changes of the scanning optical system.
A holding means is provided that is rotatable around the holding means, and the holding means holds the laser light source.
And a housing fitted with the laser holding portion,
Linear expansion coefficient of material of the laser holding part and the housing
Are different from each other, and the laser holder and the housing
The rotation restricting part that relatively restricts the
The bulk material is a bulk material stay protruding from the housing.
And the bulk material receiving part of the laser holding part
And the linear expansion coefficient of the material of the bulk material is the housing
A scanning optical system characterized by having a linear expansion coefficient larger than that of the material . 7. The scanning optical system according to claim 5, wherein the scanning optical system has at least one resin lens. 8. The scanning optical system according to claim 5 , wherein the rotation restricting portion has a fitted long hole and a boss, and the boss is attached to the housing. 9. An image forming apparatus using the scanning optical system according to claim 1 in an image forming apparatus.