JP2020086265A - Optical scanning optical device - Google Patents

Abstract

To provide an optical scanning optical device that comprises a configuration not adversely affecting alignment accuracy in an optical axis direction of a scanning optical member in the optical scanning optical device.SOLUTION: A scanning optical system of the optical scanning optical device includes a scanning optical member 100 that has power in a main scan direction. A linear expansion coefficient of the scanning optical member 100 and a linear expansion coefficient of a support member 200 are different, in which the support member 200 includes: a first alignment unit 210 of an optical axis direction with respect to the scanning optical member 100; and a second alignment unit 200a of a main scan direction with respect to the scanning optical member 100. The first alignment unit 210 includes: one alignment unit on one end side in the main scanning direction; and two alignment units on the other end side in the main scanning direction. The second alignment unit 200a is provided closer to a side of the two alignment units 210 provided on the other side in the main scanning direction than to the one portion relative to the one alignment unit on the one end side in the main scanning direction.SELECTED DRAWING: Figure 6

Description

The present invention relates to a technique for adhesively fixing a scanning optical member in an optical scanning optical device.

Japanese Patent Laying-Open No. 2011-197081 (Patent Document 1) discloses a configuration relating to an optical scanning optical device.

An adhesive is used to fix the scanning optical member used in the optical scanning optical device to the support member. When the temperature of the surrounding environment of the long scanning optical member changes, a difference in thermal expansion occurs between the scanning optical member and the supporting member having different linear expansion coefficients, and the adhesive pulls the scanning optical member and the housing. Be done.

In this case, since the scanning optical member is fixed to the supporting member in the state where the adhesive is a thick film, the difference in thermal expansion between the scanning optical member and the supporting member is due to the adhesive being in the shearing direction. It is absorbed by being deformed, and peeling of the adhesive and deformation of the scanning optical member are suppressed.

JP, 2011-197081, A

If the position of the scanning optical member in the optical axis direction deviates from the designed value, the optical performance is adversely affected. Therefore, in order to position the scanning optical member in the optical axis direction, a positioning portion in the optical axis direction is provided between the scanning optical member and the support member.

However, in order to make the optical scanning optical device compact in recent years, the positioning portion and the adhesive portion in the optical axis direction may be arranged close to each other. In this case, there is a possibility that the adhesive may reach the positioning portion in the optical axis direction before the curing due to the positional variation at the time of applying the adhesive and the deformation until curing.

When the adhesive reaches the positioning portion in the optical axis direction, the thin film is adhered in the vicinity of the reached position, and the shearing force when the temperature rises is applied to the thin film, leading to a decrease in the adhesive strength of the adhesive. As a result, there is concern that the positioning accuracy of the scanning optical member in the optical scanning optical device in the optical axis direction may be adversely affected.

The present invention is to solve the above problems, and an object thereof is to provide an optical scanning optical device having a configuration that does not adversely affect the positioning accuracy of the scanning optical member in the optical scanning optical device in the optical axis direction. ..

An optical scanning optical device according to the present invention is an optical scanning optical device that deflects and scans light emitted from a light source in a main scanning direction by a predetermined optical element, and deflects an optical axis emitted from the light source. A scanning deflector, a scanning optical system for forming an image of an optical axis deflected by the deflector on a surface to be scanned, and a supporting member for holding the scanning optical system, the scanning optical system is provided with: The scanning optical member having a power in the main scanning direction is included, and the linear expansion coefficient of the scanning optical member and the linear expansion coefficient of the support member are different from each other, and the support member has a first positioning in the optical axis direction with respect to the scanning optical member. And a second positioning portion in the main scanning direction with respect to the scanning optical member, wherein the first positioning portion includes one positioning portion on one end side in the main scanning direction, and another portion in the main scanning direction. The second positioning portion includes two positioning portions on the end side, and the second positioning portion is provided at two locations on the other end side in the main scanning direction than one positioning portion on one end side in the main scanning direction. It is provided on the side of the positioning unit.

In another aspect, the second positioning portion is provided near the two positioning portions provided on the other end side in the main scanning direction.

In another aspect, the second positioning portion is provided at one end side in the main scanning direction when viewed with reference to the two positioning portions provided at the other end side in the main scanning direction. There is.

According to the present invention, it is possible to provide an optical scanning optical device having a configuration that does not adversely affect the positioning accuracy of the scanning optical member in the optical axis direction in the optical scanning optical device.

It is a schematic diagram which shows the structure of the optical scanning optical device in an embodiment. FIG. 3 is a plan view showing how the scanning lens of the embodiment is attached to the lens holder. FIG. 6 is a plan view showing a fixed state of a scanning lens to a support member in a related art. FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3. FIG. 6 is a cross-sectional view schematically showing a state in which a problem has occurred in the adhesive due to the difference in thermal expansion between the scanning lens and the supporting member in the related art. FIG. 3 is a plan view showing how the scanning lens of the embodiment is attached to the lens holder. FIG. 7 is a sectional view taken along the line VII-VII in FIG. FIG. 8 is a sectional view taken along the line VIII in FIG. It is a top view which shows the attachment state to the lens holder of the scanning lens of other embodiment.

An optical scanning optical device according to an embodiment of the present invention will be described with reference to the drawings. In the embodiments described below, when referring to the number, amount, etc., the scope of the present invention is not necessarily limited to the number, amount, etc., unless otherwise specified. In addition, the same parts or corresponding parts may be designated by the same reference numerals, and duplicate description may not be repeated. The optical axis shown in each of the following figures illustrates the principal ray of light emitted from each light source.

(Embodiment 1: Schematic configuration of optical scanning optical device)
The optical scanning optical device according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a diagram showing a schematic configuration of the optical scanning optical device of the present embodiment, and FIG. 2 is a plan view showing a mounting state of a scanning lens on a lens holder.

Referring to FIG. 1, an optical scanning optical device, a laser diode 1 as a light source, a collimator lens 2, a mirror 3, a mirror 4, a cylinder lens 5, a polygon mirror 10, scanning lenses 11, 12, and 13, a lens 14, and a mirror 15. , 16, a lens 17, and a dustproof glass 18.

The optical axis emitted from the laser diode 1 is deflected at a constant angular velocity in the main scanning direction (Y direction) by the polygon mirror 10, and the scanning lenses 11 and 12 having power (fθ function) in the main scanning direction (Y direction). , 13 corrects the aberration in the main scanning direction Y, and scanning/exposure is performed in a state where an image is formed on the photoconductor 20. The scanning lenses 11, 12, 13 have an elongated shape extending in the main scanning direction Y. In each figure, the arrow Y direction indicates the main scanning direction, the arrow X direction indicates the sub scanning direction, and the arrow Z direction indicates the traveling direction of the optical axis.

As shown in FIG. 2, the scanning lenses 11, 12, and 13 are integrally assembled on the supporting member 200 as one unit. The bottom surfaces of the scanning lenses 11, 12 and 13 are flat mounting reference planes on the XY plane. The scanning lenses 11, 12, and 13 are made of glass, and the support member 200 is made of resin. Therefore, the linear expansion coefficient of the scanning lens 100 and the linear expansion coefficient of the supporting member 200 are different.

As a related technique, positioning and fixing of the scanning lens to the supporting member 200 will be described with reference to FIGS. 3 to 5. In the scanning lens 100 shown in FIGS. 3 to 5, for convenience of description, the scanning lenses 11, 12, and 13 are schematically represented in a rectangular shape. FIG. 3 is a plan view showing a state where the scanning lens 100 is fixed to the supporting member 200, and the scanning lens 100 is shown by a chain double-dashed line for convenience of explanation. 4 is a cross-sectional view taken along the line IV-IV in FIG. 3, and FIG. 5 is a cross-sectional view schematically showing a state in which the adhesive has a problem due to a difference in thermal expansion between the scanning lens 100 and the supporting member 200. is there.

3 and 4, the linear expansion coefficient of scanning lens 100 and the linear expansion coefficient of supporting member 200 are different as described above. The support member 200 has a first positioning portion 210 in the optical axis direction (Z direction) with respect to the scanning lens 100.

The first positioning section 210 has one positioning section on one end side (left side in the drawing) in the main scanning direction (Y direction) and two positioning sections on the other end side (right side in the drawing) in the main scanning direction (Y direction). Including the positioning part. On both sides of each first positioning portion 210, a thick film adhesive layer 220 is provided on a minute height convex base 201 provided on the support member 200.

Due to the rotation of the driving motor of the polygon mirror 10, the light emission of the laser diode 1, and the heat transfer from the surroundings, a temperature rise occurs during the operation of the optical scanning optical device, and the scanning lens 100 and the supporting member 200 having different linear expansion coefficient differences are formed. A difference in thermal expansion occurs between them, and the adhesive layers 220 are deformed in the shearing direction by being relatively separated in the main scanning direction (Y direction). By using an ultraviolet curable adhesive having a low Young's modulus for the adhesive layer 220, a large shearing force is not generated even when deformed during thermal expansion, and peeling of the adhesive and deformation of the scanning lens 100 are suppressed.

As described above, the adhesive layer 220 absorbs the thermal expansion difference between the scanning lens 100 and the support member 200 by the deformation of the adhesive layer 220 in the shearing direction, and the adhesive layer 220 itself. It is possible to prevent the peeling and the deformation of the scanning lens 100.

The scanning lens 100 is provided with a first positioning portion 210 in the optical axis direction for positioning in the optical axis direction because the optical performance is affected if the position in the optical axis direction (Z direction) deviates from the design value. However, in order to make the optical scanning optical device compact, the first positioning portion 210 and the adhesive layer 220 in the optical axis direction may be arranged close to each other.

With reference to FIG. 5, when the first positioning portion 210 in the optical axis direction and the adhesive layer 220 are close to each other, the adhesive varies due to position variation during application of the adhesive and deformation of the adhesive until it hardens. May reach the first positioning portion 210 in the optical axis direction before being cured.

When the adhesive reaches the first positioning portion 210 in the optical axis direction, the thin film is in a bonded state in the vicinity of the reached position, a shearing force is generated at the thin film portion when the temperature rises, and the adhesive strength of the bonded portion is reduced. As a result, there is a concern that the positioning accuracy of the scanning lens 100 in the optical axis direction in the optical scanning optical device may be adversely affected.

Therefore, the optical scanning optical device according to the present embodiment has a configuration for solving such a problem. Hereinafter, description will be given with reference to FIGS. 6 to 8. FIG. 6 is a plan view showing how the scanning lens of the present embodiment is attached to the lens holder, and the scanning lens 100 is shown by a chain double-dashed line for convenience of explanation. 7 is a sectional view taken along the line VII-VII in FIG. 6, and FIG. 8 is a sectional view taken along the line VIII in FIG.

In the optical scanning optical device according to the present embodiment, the scanning lens 100 is held at its outer periphery by a lens holder 230 made of sheet metal. In a plan view, the lens holder 230 is not provided in the area where the scanning lens 100 is provided in order to transmit light.

With reference to FIGS. 6 and 7, a first positioning unit 210 is provided between the lens holder 230 and the support member 200, similarly to the optical scanning optical device described in FIGS. 3 and 4. The first positioning section 210 has one positioning section on one end side (left side in the figure) in the main scanning direction (Y direction) and two positioning sections 210 on the other end side (right side in the figure) in the main scanning direction (Y direction). Includes positioning parts. On both sides of each of the first positioning portions 210, a thick film adhesive layer 220 is provided on the minute height base 201 provided on the support member 200.

In the present embodiment, the support member 200 includes, in addition to the first positioning portion 210 in the optical axis direction (Z direction) with respect to the scanning lens 100, the second positioning portion 200a in the main scanning direction (Y direction) with respect to the scanning lens 100. including.

The second positioning portion 200a is closer to two first positioning portions 210 provided on the other end side in the main scanning direction than one first positioning portion 210 (left side in the drawing) on one end side in the main scanning direction. It is provided in. More specifically, it is provided in the vicinity of the two first positioning portions 210 provided on the other end side in the main scanning direction.

With reference to FIG. 8, the second positioning portion 200 a has a convex shape that projects from the support member 200 toward the side surface of the lens holder 230 on the side surface of the lens holder 230. On the other hand, on the side surface of the lens holder 230, a concave portion 230b for receiving the convex-shaped second positioning portion 200a is provided.

The inner diameter of the concave portion 230b has a shape capable of accepting the outer diameter of the convex-shaped second positioning portion 200a, and is dimensioned so that no gap is formed between the two.

Referring to FIG. 6 again, in the present embodiment, support member 200 is provided with convex portion 200b that abuts the side surface of lens holder 230. The convex portion 200b suppresses movement in one direction (the lower side in the drawing) in the sub-scanning direction (X direction). Furthermore, since the second positioning portion 200a is surrounded by the concave portion 230b, movement to the other side (upper side in the drawing) in the sub-scanning direction (X direction) is suppressed. This makes it possible to suppress the movement of the support member 200 in the X direction, the Y direction, and the Z direction.

As described above, according to the optical scanning optical device of the present embodiment, the convex-shaped second positioning portion 200a is fitted into the concave portion 230b of the lens holder 230, so that the distance between the scanning lens 100 and the support member 200 is increased. Due to the difference in thermal expansion between the two, the movement of the scanning lens 100 with respect to the support member 200 in the main scanning direction (Y direction) and the sub scanning direction (X direction) can be suppressed.

Regarding the relationship between the second positioning portion 200a and the recessed portion 230b in the present embodiment, the second positioning portion 200a can move in at least the recessed portion 230b in the main scanning direction (Y direction direction) and the sub scanning direction (X direction). Since the regulated wall is provided, movement in these directions is suppressed. Therefore, the wall located in the optical axis direction (Z direction) is not always required.

The positioning of the movement in the optical axis direction (Z direction) is ensured by the curing shrinkage stress of the first positioning part 210 and the adhesive that pulls the lens holder 230 on the first positioning part 210. The curing shrinkage stress is a stress caused by shrinkage when the adhesive cures. Even if the adhesive tries to shrink the volume when it cures, the optical axis direction (Z direction) is fixed, so it cannot be sufficiently shrunk, and the adhesive is stretched by the amount that cannot be shrunk. A force for pulling the lens holder 230 in the direction (Z direction) can be generated.

With the above configuration, it is possible to provide an optical scanning optical device having a configuration that does not adversely affect the positioning accuracy of the scanning lens 100 in the optical axis direction (Z direction).

In the above-described embodiment, the second positioning section 200a is provided at two locations on the first positioning section 210 side. The positioning portion in the main scanning direction (Y direction) serves as a starting point in the main scanning direction of thermal expansion when the temperature rises.

By setting the position of the second positioning portion 200a, which is the positioning portion in the main scanning direction, in the main scanning direction to the two first positioning portions 210 side, the linear expansion coefficient of the scanning lens 100 and the support member 200 when the temperature rises. Even when a difference in thermal expansion occurs due to the difference, the two first positioning portions 210 are closer to the first positioning portion 210 side than the one starting point, so that the difference in thermal expansion can be reduced. When the difference in thermal expansion becomes small, the shearing force becomes small even if a thin film bonding portion occurs in the adhesive layer 220. Therefore, the position of the second positioning portion 200a in the main scanning direction is two first positioning portions 210. Good to be on the side.

In the above-described embodiment, the second positioning section 200a has one end side in the main scanning direction (Y direction) when viewed with the first positioning section 210 as a reference in the vicinity of the two first positioning sections 210. Although it is provided on one side of the first positioning portion 210: on the left side in the drawing), it may be provided on the right side in the drawing when the first positioning portion 210 is used as a reference.

(Other embodiments)
An optical scanning optical device according to another embodiment will be described with reference to FIG. FIG. 9 is a plan view showing how the scanning lens of another embodiment is attached to the lens holder, and the scanning lens 100 is indicated by a chain double-dashed line for convenience of explanation.

In the above-described embodiment, the second positioning portion 200a has a configuration that also serves as positioning in the sub-scanning direction (X direction) other than the main scanning direction (Y direction), but the second positioning portion 200c shown in FIG. Performs only positioning in the main scanning direction (Y direction). The second positioning portion 200c is provided at a position where it abuts on the end surface of the lens holder 230 in the main scanning direction (Y direction). With this configuration also, it is possible to provide an optical scanning optical device having a configuration that does not adversely affect the positioning accuracy of the scanning lens 100 in the optical axis direction (Z direction).

In the above embodiment, the scanning lens 100 having the power (fθ function) in the main scanning direction (Y direction) has been described, but it has the power in the sub scanning direction (X direction) at the same time as the main scanning direction (Y direction). May be. It may also be a curved reflecting member.

Although the configuration in which the lens holder 230 is provided in the scanning lens 100 has been described, the recess 230b for receiving the convex second positioning portion 200a may be provided in the scanning lens 100 without providing the lens holder 230.

The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

1 laser diode, 2 collimator lens, 3,4,15,16 mirror, 5 cylinder lens, 10 polygon mirror, 11,12,13,100 scanning lens, 14,17 lens, 18 dustproof glass, 20 photoconductor, 200 support Member, 200a, 200c second positioning part, 200b convex part, 201 convex part base, 210 first positioning part, 220 adhesive layer, 230 lens holder, 230b concave part.

Claims (3)

An optical scanning optical device for deflecting and scanning light emitted from a light source in a main scanning direction by a predetermined optical element,
A deflector for deflecting and scanning the optical axis emitted from the light source,
A scanning optical system for forming an image of the optical axis deflected by the deflector on the surface to be scanned,
A support member for holding the scanning optical system,
Equipped with
The scanning optical system includes a scanning optical member having a power in the main scanning direction,
Different from the linear expansion coefficient of the scanning optical member and the support member,
The support member includes a first positioning portion in the optical axis direction with respect to the scanning optical member, and a second positioning portion in the main scanning direction with respect to the scanning optical member,
The first positioning unit includes one positioning unit on one end side in the main scanning direction and two positioning units on the other end side in the main scanning direction,
The second positioning section is provided on two positioning section sides provided on the other end side in the main scanning direction rather than one positioning section on one end side in the main scanning direction. Scanning optics. The optical scanning optical device according to claim 1, wherein the second positioning section is provided in the vicinity of the two positioning sections provided on the other end side in the main scanning direction. The said 2nd positioning part is provided in the one end side of the said main scanning direction, when it sees with reference to the said two positioning parts provided in the other end side of the said main scanning direction. The optical scanning optical device described.

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