Optical mirror, scanning optical device, image forming apparatus, and method for manufacturing optical mirror

Abstract

To provide an optical mirror that can prevent the occurrence of variations of a resonance frequency due to variations of a length of an adhesive layer and resonance in an image forming apparatus, and hardly imposes a burden on an operator during manufacture of the optical mirror, a scanning optical device including the optical mirror, an image forming apparatus, and a method for manufacturing an optical mirror.SOLUTION: A long-shaped optical mirror has: a substrate; a mirror that includes a reflecting surface formed on one end face in a thickness direction of the substrate; a long-shaped reinforcement member that is bonded to a surface of the mirror on the opposite side of the reflecting surface; and an adhesive layer that is arranged between the mirror and the reinforcement member. The adhesive layer partially covers a bonding surface between the mirror and the reinforcement member. On a central axis extending in a longitudinal direction of the bonding surface, the total length in the longitudinal direction of the adhesive layer is 40% or more of a length in the longitudinal direction of the bonding surface.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an optical mirror, a scanning optical device, an image forming device, and a method for manufacturing an optical mirror. [Background technology]

[0002] Conventionally, an electrophotographic image forming apparatus using toner includes a scanning optical device for exposing a uniformly charged photoconductor surface to light to form an electrostatic latent image. The scanning optical device includes a light source and an elongated optical mirror for reflecting the light emitted from the light source toward the photoconductor surface.

[0003] Vibrations occur inside an image forming apparatus during operation. If the frequency of vibrations caused by the operation of the image forming apparatus coincides with the resonance frequency of the optical mirror, the optical mirror will resonate. When the optical mirror resonates, the exposure position relative to the photosensitive member changes, and this causes uneven density in the image. As an optical mirror for suppressing resonance, one in which a reinforcing member is adhered to the surface opposite the reflective surface of the mirror body is known.

[0004] For example, Patent Document 1 discloses an optical mirror in which a flatness reinforcing member with a flatness of 100 mR or more is fixed to the surface opposite the reflecting surface of the optical mirror with an adhesive or the like, and an optical mirror scanning device including the optical mirror. Patent Document 1 states that the optical mirror can provide a vibration damping effect without impairing the flatness of the optical mirror.

[0005] Also, Patent Document 2 discloses a reflecting mirror for optical scanning in which a glass plate is bonded to the rear surface of a plastic reflecting mirror with an adhesive. According to Patent Document 2, the reflecting mirror is said to be resistant to warping, highly accurate, and easy to manufacture. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 8-106129 [Patent Document 2] Japanese Patent Application Publication No. 6-175006 Summary of the Invention [Problem to be solved by the invention]

[0007] However, when the mirror body and the reinforcing member are bonded with an adhesive, the resonance frequency of the optical mirror is likely to vary significantly due to a slight change in the length of the adhesive layer in the longitudinal direction of the adhesive surface, depending on the bonding method. Also, depending on the bonding method, the resonance frequency of the optical mirror is likely to match the frequency of vibration caused by the operation of the image forming apparatus, and the optical mirror is likely to resonate.

[0008] According to the inventors' study, the above-mentioned fluctuation in the resonance frequency can be suppressed by applying an adhesive to the entire bonding surface between the mirror body and the reinforcing member. Also, by bonding the entire surface between the mirror body and the reinforcing member, the resonance frequency of the optical mirror increases, making it difficult for the resonance frequency of the optical mirror to coincide with the frequency of vibration caused by the operation of the image forming apparatus.

[0009] However, if adhesive is applied to the entire bonding surfaces of the mirror body and the reinforcing member, the adhesive will overflow when these members are pressed together during bonding, resulting in the need for cleaning and other tasks, which places a burden on the worker.

[0010] An object of the present invention is to provide an optical mirror that can suppress fluctuations in resonant frequency due to fluctuations in the length of an adhesive layer and the occurrence of resonance within an image forming device, and that imposes little burden on workers during its manufacture, a scanning optical device that includes the optical mirror, an image forming device, and a method for manufacturing the optical mirror. [Means for solving the problem]

[0011] One aspect of the present invention relates to an optical mirror according to any one of [1] to

[12] . [1] An optical mirror having a long shape, a substrate; and a mirror including a reflective surface formed on one end surface of the substrate in a thickness direction; a reinforcing member having an elongated shape and bonded to a surface of the mirror opposite to the reflecting surface; an adhesive layer disposed between the mirror and the stiffening member; the adhesive layer partially covers an adhesive surface between the mirror and the reinforcing member; In the longitudinal direction of the adhesive surface, the total maximum length of the adhesive layer in the longitudinal direction is 40% or more of the length of the adhesive surface in the longitudinal direction. Optical mirror. [2] The optical mirror according to [1], wherein the total length of the adhesive layer in the longitudinal direction of the mirror is 60% or more of the longitudinal length of the mirror. [3] The optical mirror according to [1] or [2], wherein the adhesive layer is composed of a plurality of adhesive portions. [4] The optical mirror according to [3], wherein the plurality of adhesive portions are arranged at equal intervals. [5] The optical mirror according to [1] or [2], wherein the adhesive layer is an adhesive layer formed by partially connecting a plurality of adhesive portions. [6] The optical mirror according to any one of [1] to [5], wherein the reinforcing member is made of glass. [7] The optical mirror according to [6], wherein the reinforcing member has a thickness smaller than that of the mirror and has an unpolished surface. [8] The optical mirror according to [6] or [7], wherein the material of the substrate of the mirror and the material of the reinforcing member are the same. [9] The optical mirror according to any one of [1] to [8], wherein the adhesive layer is an adhesive layer formed by curing an ultraviolet-curable adhesive.

[10] The optical mirror according to any one of [1] to [9], wherein the mirror and the reinforcing member have the same length in the longitudinal direction and the same width.

[0012] Another aspect of the present invention relates to a scanning optical device according to

[11] to

[13] .

[11] A scanning optical device comprising the optical mirror according to any one of [1] to

[10] .

[12] The scanning optical device according to

[11] , further comprising a pressing member for pressing the reinforcing member of the optical mirror toward the mirror.

[13] The optical mirror further includes support members disposed at both ends of the reflecting surface of the optical mirror in a longitudinal direction thereof for supporting the mirror from the reflecting surface side; The scanning optical device according to

[11] , wherein the adhesive layer is arranged so that at least a portion of the adhesive layer overlaps with the position where the support member is arranged in a plan view from the reflecting surface side.

[0013] Another aspect of the present invention relates to an image forming apparatus according to the above item

[14] .

[14] An image forming apparatus having the scanning optical device according to

[13] .

[0014] Another aspect of the present invention relates to a method for producing an optical mirror according to any one of

[15] to

[17] .

[15] A step of applying an adhesive to a surface of a mirror opposite to a reflective surface at a plurality of spaced locations; attaching a reinforcing member to the adhesive-coated surface of the mirror; bonding the mirror and the reinforcing member; A method for manufacturing an optical mirror, comprising:

[16] The method for manufacturing an optical mirror according to

[15] , wherein the adhesive is dot-applied in the applying step.

[17] The adhesive is an ultraviolet-curable adhesive, The method for manufacturing an optical mirror described in

[15] or

[16] , wherein, in the bonding step, the mirror and the reinforcing member are placed in an ultraviolet irradiation furnace to harden the adhesive and bond the mirror and the reinforcing member. Effect of the Invention

[0015] According to the present invention, it is possible to provide an optical mirror that can suppress fluctuations in resonant frequency due to fluctuations in the length of the adhesive layer and the occurrence of resonance within an image forming apparatus, and that imposes little burden on workers during its manufacture, a scanning optical device that includes the above-mentioned optical mirror, an image forming apparatus, and a method for manufacturing the optical mirror. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic cross-sectional view showing the configuration of an optical mirror according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view of the adhesive surface and adhesive layer between the mirror and the reinforcing member in the first embodiment, as viewed from the reflective surface side. [Diagram 3] FIG. 3 is a flowchart showing a method for manufacturing an optical mirror. [Figure 4] FIG. 4 is a schematic diagram showing a state in which the reinforcing member is pressed and bonded to the mirror. [Diagram 5] FIG. 5 is a schematic cross-sectional view showing an example of the configuration of an image forming apparatus. [Figure 6] FIG. 6 is an external perspective view showing the configuration of the scanning optical device. [Figure 7] FIG. 7 is a plan view of the external appearance of the scanning optical device as viewed from above in the vertical direction. [Figure 8] FIG. 8 is a schematic cross-sectional view of the scanning optical device taken along a horizontal plane passing vertically below the upper surface of the optical deflector. [Figure 9] FIG. 9 is a schematic cross-sectional view of the scanning optical device taken along line DD in FIG. [Figure 10] FIG. 10 is a schematic diagram showing an example of an embodiment of an optical mirror included in a scanning optical device. [Figure 11] FIG. 11 is a plan view of the optical mirror with the support members attached, as viewed from the reflecting surface side. [Figure 12] FIG. 12 is a plan view of the adhesive surface and adhesive layer between the mirror and the reinforcing member of the optical mirror according to the second embodiment, viewed from the reflecting surface side. [Figure 13] FIG. 13 is a graph showing the relationship between the length of the adhesive layer of the optical mirrors 1 to 8 and the resonance frequency of the primary bending vibration in the examples. [Figure 14] FIG. 14 is a graph showing the relationship between the length of the adhesive layer of the optical mirrors 1 to 8 and the resonance frequency of the secondary bending vibration in the examples. [Figure 15] FIG. 15 is a plan view of the adhesive surface and adhesive layer between the mirror and the reinforcing member of the optical mirror 11 in the embodiment, viewed from the reflecting surface side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described in detail. However, the present invention is not limited to the following embodiment.

[0018] 1. First embodiment 1-1.Optical mirror Fig. 1 is a schematic cross-sectional view showing the configuration of an optical mirror 100 according to embodiment 1. As shown in Fig. 1, the optical mirror 100 is an elongated optical mirror, and includes a mirror 110, a reinforcing member 120 bonded to the surface of the mirror 110 opposite to a reflecting surface 112, and an adhesive layer 130 disposed between the mirror 110 and the reinforcing member 120. In this specification, the term "elongated shape" refers to a shape having an aspect ratio (longitudinal length / shortitudinal length) of 7.5 or more.

[0019] 1-1-1. Mirror The mirror 110 includes a substrate 111 and a reflecting surface 112 formed on one end surface in the thickness direction of the substrate 111. The mirror 110 has an elongated shape.

[0020] The material of the substrate 111 is not particularly limited, but may be, for example, glass or a metal such as aluminum or SPCC. Of these, glass is preferable as the material of the substrate 111. The size of the substrate 111 may be appropriately adjusted in accordance with the design of the optical mirror 110.

[0021] Reflective surface 112 has a function of reflecting light. Examples of materials for reflective surface 112 include aluminum, chromium, titanium, and the like. Of these, the material for reflective surface 112 is preferably aluminum. Reflective surface 112 may be formed on the entire surface of the one end face of substrate 111, or may be formed on a part of the one end face, but is preferably formed on the entire surface of the one end face.

[0022] The reflecting surface 112 can be formed on the one end surface of the substrate 111 by performing a method such as deposition or sputtering using the above-mentioned material.

[0023] 1-1-2. Reinforcement members The reinforcing member 120 is bonded to the surface of the mirror 110 opposite the reflecting surface 112, and can increase the rigidity of the mirror 110.

[0024] The shape of the reinforcing member 120 is not particularly limited, but is preferably an elongated shape. In this case, the length and width of the reinforcing member 120 in the longitudinal direction are preferably the same as the length and width of the mirror 110 in the longitudinal direction. This allows the mirror 110 (particularly the substrate 111) and the reinforcing member 120 to be manufactured using the same processing tool for processing the base material, and allows the transport cases to be made similar in shape, thereby reducing the cost of manufacturing these members.

[0025] The material of the reinforcing member 120 is not particularly limited, but may be, for example, glass or SPCC. Of these, from the viewpoint of further increasing the rigidity of the mirror 110, it is preferable that the material of the reinforcing member 120 is glass. Moreover, it is preferable that the material of the reinforcing member 120 is the same type as the material of the substrate 111 of the mirror 110. This makes it difficult for a difference to occur in the degree of thermal expansion between the two, and therefore makes it possible to make it difficult for the optical mirror 100 to deform due to heat in the image forming apparatus.

[0026] When the material of the reinforcing member 120 is glass, the thickness of the reinforcing member 120 is preferably smaller than that of the mirror 110, and more preferably 50% to 60% of the thickness of the mirror 110. This makes it difficult for the flatness of the reinforcing member 120 to be damaged, and the reinforcing member 120 and the mirror 110 are less likely to slip when they are bonded together. Furthermore, when the thickness of the glass reinforcing member 120 is smaller than that of the mirror 110, it is preferable that the surface of the reinforcing member 120 is unpolished. Since the thickness of the reinforcing member 120 is smaller than that of the mirror 110, the mirror 110 is less likely to deform compared to the reinforcing member 120, so that even if the surface of the reinforcing member 120 is unpolished, the flatness of the optical mirror 100 as a whole is less likely to decrease. Furthermore, by using an unpolished glass reinforcing member 120, the cost of manufacturing the optical mirror 100 can be reduced.

[0027] 1-1-3.Adhesive layer The adhesive layer 130 is disposed between the mirror 110 and the reinforcing member 120. FIG. 2 is a plan view of the adhesive surface 120a between the mirror 110 and the reinforcing member 120 and the adhesive layer 130, viewed from the reflection surface 112 side. The adhesive layer 130 partially covers the adhesive surface 120a between the mirror 110 and the reinforcing member 120, and in the longitudinal direction of the adhesive surface 120a (the direction of the arrow A in FIG. 2), the total of the maximum length of the adhesive layer 130 in the longitudinal direction (the length of the arrow a in FIG. 2) is 40% or more of the longitudinal length of the adhesive surface 120a. In this specification, the "adhesive surface 120a" refers to the surface of the reinforcing member 120 where the mirror 110 and the reinforcing member 120 are in contact. In addition, the "longitudinal direction" refers to the direction in which the long side of the adhesive surface 120a extends.

[0028] According to the study by the present inventors, it was found that when the total length of the adhesive layer 130 in the longitudinal direction of the adhesive surface 120a is short, a slight variation in the length is likely to cause a large variation in the resonant frequency of the optical mirror. The slight variation in the length can be caused by a difference in the degree of pressure of the reinforcing member 120 during adhesion, etc. It was also found that when the length is short, the resonant frequency of the optical mirror is likely to match the frequency of vibration caused by the operation of the image forming apparatus.

[0029] Therefore, the inventors have found that by setting the total maximum length of the adhesive layer 130 in the longitudinal direction of the adhesive surface 120a to 40% or more of the longitudinal length of the adhesive surface 120a, the resonant frequency of the optical mirror can be made less likely to fluctuate even if the length fluctuates. The inventors have also found that by setting the total length to 40% or more of the longitudinal length of the adhesive surface 120a, the resonant frequency of the optical mirror 100 can be made closer to the value when the mirror 110 and the reinforcing member 120 are bonded by applying an adhesive to the entire surface of the adhesive surface 120a between the mirror 110 and the reinforcing member 120 (i.e., when the adhesive layer 130 covers the entire surface of the adhesive surface 120a). This makes it possible to suppress the resonance of the optical mirror 100 caused by the vibration of the image forming device.

[0030] In the optical mirror 100 of this embodiment, the adhesive layer 130 partially covers the adhesive surface 120a, so that the adhesive is less likely to overflow between the mirror 110 and the reinforcing member 120. This reduces the burden on the worker when manufacturing the optical mirror 100.

[0031] In this specification, when the terms "resonant frequency" and "resonance" are used simply, they refer to the resonant frequency and resonance of the first bending vibration of the optical mirror 100. The first bending vibration has a large amplitude, so periodic density unevenness in an image is easily visible. Therefore, it is important to suppress the fluctuations in the resonance and resonant frequency of the first bending vibration in order to operate an image forming apparatus.

[0032] The total maximum length of the adhesive layer 130 in the longitudinal direction of the adhesive surface 120a is preferably 40% or more, and more preferably 60% or more, of the longitudinal length of the adhesive surface 120a. When the total maximum length is 60% or more, the variation in the resonance frequency of the secondary bending vibration of the optical mirror 100 caused by the variation in the length of the adhesive layer 130 can be suppressed. Furthermore, when the total maximum length is 60% or more, the resonance frequency of the secondary bending vibration of the optical mirror 100 can be made close to the value when the adhesive is applied to the entire surface of the adhesive surface 120a between the mirror 110 and the reinforcing member 120 and bonded. When the adhesive layer 130 covers the entire surface of the adhesive surface 120a, resonance of the secondary bending vibration is unlikely to occur in the image forming device. Therefore, when the total maximum length is 60% or more, resonance of the secondary bending vibration of the optical mirror 100 caused by the vibration of the image forming device can be suppressed. The upper limit of the total length is, for example, 100% of the length of the adhesive surface 120a in the longitudinal direction.

[0033] The adhesive layer 130 may only partially cover the adhesive surface 120a, but the area covered by the adhesive layer 130 is preferably 30% or more, and more preferably 50% or more, of the area of ​​the adhesive surface 120a.

[0034] In this embodiment, the adhesive layer 130 is composed of a plurality of adhesive parts 131, and each of the plurality of adhesive parts 131 is composed of an adhesive. The adhesives constituting the plurality of adhesive parts 131 may be of the same type or different types.

[0035] The planar shape of the multiple adhesive parts 131 is not particularly limited, but may be, for example, a circle or an ellipse. Of these, a circle is preferable. If the shape is set to a circle, when the adhesive applied to the substrate is pressed with the reinforcing member in the step (step S20) of bonding the reinforcing member and the mirror described later, it is not necessary to move the reinforcing member in the in-plane direction of the substrate, which facilitates the bonding operation and the preparation of a jig for bonding. In the example of FIG. 2, the planar shape is a circle. In addition, it is preferable that all of the multiple adhesive parts 131 are arranged on a central axis Ax extending in the longitudinal direction of the bonding surface 120a.

[0036] The intervals between the multiple adhesive parts 131 may be equal or unequal, but are preferably equal. When the intervals between the multiple adhesive parts 131 are equal, the resonance frequency of the optical mirror 100 can be made closer to the value when the adhesive layer 130 covers the entire adhesive surface 120a between the mirror 110 and the reinforcing member 120.

[0037] The thickness of the adhesive layer 130 (the adhesive portions 131 in this embodiment) is not particularly limited, but is preferably greater than 0 mm and less than 0.05 mm, which can increase the adhesive strength between the mirror 110 and the reinforcing member 120 and suppress the variation in the resonant frequency due to the deformation of the adhesive layer 130 or the variation in the thickness.

[0038] The type of adhesive constituting the adhesive layer 130 (the plurality of adhesive portions 131 in this embodiment) is not particularly limited, but it is preferable that the adhesive layer 130 (the plurality of adhesive portions 131) is an adhesive layer (adhesive portion) formed by curing an ultraviolet-curing adhesive. An ultraviolet-curing adhesive is often used to bond members other than the optical mirror 100 together when assembling a scanning optical device in an image forming apparatus. In addition, an ultraviolet-curing adhesive is more likely to harden in a short time than other adhesives such as a thermosetting adhesive. Therefore, by using an ultraviolet-curing adhesive to bond the mirror 110 and the reinforcing member 120, the manufacturing efficiency of the scanning optical device can be improved.

[0039] 1-2. Manufacturing method of optical mirror Fig. 3 is a flowchart showing a method for manufacturing the optical mirror 100 according to this embodiment. As shown in Fig. 3, the manufacturing method includes a step of applying an adhesive to a surface of a mirror opposite to a reflecting surface at a plurality of intervals (step S10), a step of attaching a reinforcing member to the adhesive-applied surface of the mirror (step S20), and a step of bonding the mirror and the reinforcing member together (step S30).

[0040] 1-2-1. Step of applying adhesive (step S10) In this step, an adhesive is applied at multiple locations at intervals on the surface of the mirror 110, including the reflective surface 112, opposite the reflective surface 112. The type of adhesive is not particularly limited, but an ultraviolet-curing adhesive is preferable.

[0041] The method of applying the adhesive is not particularly limited, but may be, for example, a method using a spray gun and a dispenser. The amount of adhesive to be applied can be determined according to the following procedure. First, the relationship between the amount of adhesive to be applied and the area of ​​the adhesive layer is determined by experiment. Then, assuming that the shape of the adhesive to be applied is circular in plan view, the relationship between the amount of adhesive to be applied and the maximum length of the adhesive layer in the longitudinal direction is determined from the relationship thus determined. Based on the relationship thus determined, it is possible to determine the amount of adhesive to be applied such that the sum of the maximum lengths of the adhesive layer is 40% of the longitudinal length of the adhesive surface 120a.

[0042] At this time, it is preferable to determine the above-mentioned application amount in consideration of the variation in the amount of adhesive applied by the device that applies the adhesive. For example, when applying the adhesive using a dispenser, if the variation in the amount of the dispenser discharged is ±13%, the variation in the length of the adhesive layer 130 in the longitudinal direction is empirically determined to be approximately ±6.3%. Therefore, the target value (set value) of the total maximum length in the longitudinal direction of the adhesive layer 130 is set to 46.3% of the longitudinal length of the adhesive surface 120a, and the application amount of the adhesive is set to an amount corresponding to the target value. This makes it easy to adjust the total length of the adhesive layer 130 in the longitudinal direction to a length of 40% or more of the longitudinal length of the adhesive surface 120a. In addition, by making the application interval of the adhesive larger than the spreading length (empirically determined) of the adhesive layer 130 in the set application amount of adhesive, it is possible to suppress the applied adhesive from merging with each other when bonding the adhesive mirror 110 and the reinforcing member 120. This makes it possible to adjust the adhesive layer 130 to be composed of a plurality of adhesive parts 131.

[0043] In addition, the application of the adhesive in this process may be line application, surface application, or point application. Among these, point application is preferable. By applying the adhesive in a point manner, it is not necessary to control the adhesive discharge speed or the moving speed of the discharge device, and the optical mirror 100 can be manufactured by controlling only the discharge amount. Therefore, the control of the adhesive application is simple, and the management and calibration of the device for applying the adhesive can also be simplified. Note that "point application" refers to an application method in which the adhesive is applied without moving the discharge device in the in-plane direction of the substrate, and the adhesive is not spread by any method other than crushing it with a reinforcing member.

[0044] In this step, the adhesive may be applied at equal intervals or at non-equal intervals, but it is preferable to apply the adhesive at equal intervals, which makes it easier to manufacture the optical mirror 100 in which the adhesive portions 131 are arranged at equal intervals.

[0045] The mirror 110 and the reinforcing member 120 used in this step are similar to those described for the optical mirror 100, and therefore a detailed description thereof will be omitted.

[0046] 1-2-2. Step of bonding the reinforcing member and the mirror (step S20) In this step, the reinforcing member 120 is attached to the surface of the mirror 110 to which the adhesive has been applied. The method for attaching the reinforcing member 120 to the mirror 110 is not particularly limited. The reinforcing member 120 and the mirror 110 may be attached to each other manually or by using a jig or the like.

[0047] 1-2-3. Step of bonding the reinforcing member and the mirror (step S30) In this step, the mirror 110 and the reinforcing member 120 are bonded together.

[0048] The method of bonding the mirror 110 and the reinforcing member 120 includes, for example, a method of bonding by pressing the reinforcing member 120. When the adhesive is an ultraviolet-curing adhesive, in addition to the above-mentioned pressing, the adhesive can be irradiated with ultraviolet light to cure the adhesive, thereby bonding the mirror 110 and the reinforcing member 120.

[0049] When the reinforcing member 120 is pressed and bonded, it is preferable to carry out the following procedure, for example.

[0050] 4 is a schematic diagram showing a state when the reinforcing member 120 is pressed to adhere to the mirror 110. In FIG. 4, the components are shown on a scale different from that of FIG. 1. The mirror 110 to which the reinforcing member 120 is attached is placed on an L-shaped adhering jig A with the mirror 110 facing downward. After that, the mirror 110 and the reinforcing member 120 are fixed with a clamp, and the side surfaces of both members are pressed toward the wall surface A1 of the adhering jig A (in the direction of arrow B in FIG. 4). Then, the reinforcing member 120 is pressed from above toward the mirror 110 (in the direction of arrow C in FIG. 4).

[0051] At this time, it is preferable to chamfer the ridges in advance on the bonding surface 120a between the mirror 110 and the reinforcing member 120. This makes it possible to more sufficiently prevent the adhesive from overflowing when pressed. For the same reason, it is preferable to provide a recess (a recess to prevent the adhesive from touching) on ​​the wall surface A1 of the bonding jig A.

[0052] When the adhesive is an ultraviolet-curing adhesive, it is preferable to press the mirror 110 and the reinforcing member 120 as described above, and then place them in an ultraviolet ray irradiation furnace to cure the adhesive. This allows the ultraviolet-curing adhesive to cure efficiently.

[0053] 1-3. Image forming device and scanning optical device 5 is a schematic cross-sectional view showing an example of the configuration of an image forming apparatus 300 according to this embodiment. The image forming apparatus 300 has a scanning optical device 200 including the optical mirror 100 described above.

[0054] 5, image forming apparatus 300 is a so-called tandem type color multi-function peripheral (MFP: Multi-Function Peripheral), but is not limited to this. Image forming apparatus 300 has image forming section 310, fixing device 320, image reading section 330, and paper conveying section 340.

[0055] Image forming section 310 has image forming units 311Y, 311M, 311C, and 311K that form images using toner of each color, Y (yellow), M (magenta), C (cyan), and K (black). Since these have the same configuration except for the toner contained therein, hereinafter, the symbols representing the colors may be omitted.

[0056] The image forming section 310 has a scanning optical device 200, a developing device 314, an electrophotographic photosensitive member (image carrier) 315, a charging device 316, and a drum cleaning device 317. The image forming section 310 further has an intermediate transfer unit 312 and a secondary transfer unit 313. These correspond to transfer devices.

[0057] The developing device 314 is a two-component developing device. The developing device 314 has, for example, a developing container that contains a two-component developer, a developing roller (magnetic roller) that is rotatably arranged at the opening of the developing container, a partition that divides the inside of the developing container so that the two-component developer can communicate with each other, a transport roller for transporting the two-component developer on the opening side of the developing container toward the developing roller, and a stirring roller for stirring the two-component developer in the developing container. The developing container contains, for example, a two-component developer.

[0058] The charging device 316 is, for example, a corona charger. The charging device 316 may be a contact charging device that charges the electrophotographic photoreceptor 315 by bringing a contact charging member such as a charging roller, a charging brush, or a charging blade into contact with the electrophotographic photoreceptor 315. The electrophotographic photoreceptor 315 is a negatively charged organic photoreceptor having photoconductivity. The electrophotographic photoreceptor 315 is charged by the charging device 316.

[0059] The intermediate transfer unit 312 includes an intermediate transfer belt (intermediate transfer body) 3121, a primary transfer roller 3122 that presses the intermediate transfer belt 3121 against an electrophotographic photosensitive body 315, and a belt cleaning device 3123. The intermediate transfer belt 3121 is stretched in a loop shape around a plurality of support rollers. The intermediate transfer belt 3121 runs in the direction of arrow A at a constant speed.

[0060] The belt cleaning device 3123 has an elastic member 3123a. The elastic member 3123a comes into contact with the intermediate transfer belt 3121 after the secondary transfer, and removes deposits on the surface of the intermediate transfer belt 3121. The elastic member 3123a is made of an elastic body, and includes a cleaning blade, a brush, and the like.

[0061] The secondary transfer unit 313 includes a secondary transfer roller 3131 that is in pressure contact with the outer circumferential surface of the intermediate transfer belt 3121, and a secondary transfer belt 3132. A secondary transfer voltage is applied to the secondary transfer roller 313. When the recording medium S is inserted between the intermediate transfer belt 3121 and the secondary transfer roller 127, a toner image is electrostatically transferred from the outer circumferential surface of the intermediate transfer belt 3121 onto the image forming surface of the recording medium S (secondary transfer).

[0062] The fixing device 320 is a fixing nip formed by pressing a pressure roller against a high-temperature fixing roller. A fixing belt may be used instead of the fixing roller, and a pressure pad may be used instead of the pressure roller. The toner image is thermally fixed to the recording medium S by inserting the recording medium S into the fixing nip.

[0063] The image reading unit 330 reads an original document and generates image data. The image reading unit 330 has an operation panel 331. The operation panel 331 presents information to a user of the image forming apparatus 300 and receives instruction inputs from the user.

[0064] Paper transport section 340 has paper feed section 341, paper discharge section 342, and transport path section 343. Paper S (standard paper, special paper) identified based on basis weight, size, etc. is stored by preset type in three paper feed tray units 341a to 341c that make up paper feed section 341. Transport path section 343 has multiple transport roller pairs such as registration roller pair 343a.

[0065] The scanning optical device 200 is a device for forming an electrostatic latent image by emitting light and exposing and scanning the outer peripheral surface of the electrophotographic photosensitive member 315. The light amount of the light emitted by the scanning optical devices 200Y, 200M, 200C, and 200K is adjusted according to image data of each color of YMCK.

[0066] Fig. 6 is an external perspective view showing the configuration of the scanning optical device 200. As shown in Fig. 6, the scanning optical device 200 is configured such that the protruding parts 201 protrude from the through holes 211 provided in the partition walls 210 toward the electrophotographic photosensitive member 315 side.

[0067] Fig. 7 is a plan view seen from above in the vertical direction of the exterior of the scanning optical device 200. As shown in Fig. 7, in the scanning optical device 200, a portion protruding from the partition wall 210 toward the electrophotographic photosensitive member 315 side is a protruding portion 201, and a portion located on the opposite side of the partition wall 210 to the protruding portion 201 is a storage portion 202.

[0068] An optical deflector 220 is disposed on each of the protruding portions 201 of the scanning optical device 200 and fixed to the housing 230. Each of the optical deflectors 220 has a polygon mirror 240 (described later). The light beam L emitted from the light source of the scanning optical device 200 is deflected by the polygon mirror 240 of each of the optical deflectors 220, and then emitted to the outside of the scanning optical device 200 via the scanning optical system. Then, the light beam L emitted to the outside of the scanning optical device 200 passes through a through hole 212 provided in the partition wall 210 and is incident on the outer circumferential surface of the electrophotographic photosensitive member 315. As a result, an electrostatic latent image is formed on the outer circumferential surface of the electrophotographic photosensitive member 315. In this embodiment, a space is provided between the developing device 314 and the optical deflector 220 to allow the light beam L to pass therethrough.

[0069] Heat dissipation fins 221 are provided on the upper surface 223 of the optical deflector 220. The heat dissipation fins 221 extend along the main scanning direction. A through hole for fixing a rotation shaft (polygon rotor) 241 of a polygon mirror 240 is provided on the upper surface 223 of the optical deflector 220. When the rotation shaft 241 of the polygon mirror 240 is fixed in the through hole, the tip of the rotation shaft 241 is exposed from the upper surface 223. The heat dissipation fins 221 are cut out at the location where the tip of the rotation shaft 241 is exposed.

[0070] 8 is a schematic cross-sectional view of the scanning optical device 200 cut by a horizontal plane passing vertically below the upper surface 223 of the optical deflector 220 (farther back than FIG. 7). FIG. 9 is a schematic cross-sectional view of the scanning optical device 200 cut by the line DD in FIG. 8. As shown in FIG. 8 and FIG. 9, the light source 231, the mirrors 232a, 232b, 232c, 232d, and the fθ lenses 233a, 233b, 233c, 233d, and 233e are housed in the housing 230. The light source 231, the mirrors 232a, 232b, 232c, 232d, and the fθ lenses 233a, 233b, 233c, 233d, and 233e are held on the inner wall surface of the housing 230.

[0071] The type of light source 231 is not particularly limited, but from the viewpoint of improving image quality, it is preferable that the light source 231 is a semiconductor laser.

[0072] The mirrors 232a, 232b, 232c, and 232d have a function of reflecting the light beam L to cause the light beam L to travel toward a desired position. In this embodiment, the mirrors 232c and 232d are the above-mentioned optical mirror 100. Note that the optical mirror 100 may be used for the mirror 232a and the mirror 232b.

[0073] FIG. 10 is a schematic diagram showing an example of an embodiment of the optical mirror 100 included in the scanning optical device 200. As shown in FIG. 10, the scanning optical device 200 may further include a pressing member 2321 for pressing the reinforcing member 120 toward the mirror 110. The pressing member 2321 makes it difficult for creep deformation of the adhesive layer 130 to occur when the optical mirror 100 is used for a long period of time, and makes it difficult for adhesion misalignment to occur between the mirror 110 and the reinforcing member 120, thereby suppressing fluctuations in the resonance frequency of the optical mirror 100. The pressing member 2321 is, for example, a leaf spring. It is preferable that the pressing member 2321 presses both ends 120b of the reinforcing member 120 in the longitudinal direction.

[0074] The scanning optical device 200 may further include support members 2322 arranged at both ends of the reflecting surface 112 of the mirror 110 in the longitudinal direction to support the mirror 110 from the reflecting surface 112 side. FIG. 11 is a plan view of the optical mirror 100 with the support members 2322 attached, as viewed from the reflecting surface 112 side. For the sake of explanation, FIG. 11 shows the adhesive layer 130 (in this embodiment, a plurality of adhesive portions 131) on the adhesive surface 120a by a broken line. As shown in FIG. 11, the adhesive layer 130 is arranged so that at least a part of it overlaps with the position where the support members 2322 are arranged in a plan view as viewed from the reflecting surface 112 side. This can increase the rigidity of the optical mirror 100 around the support members 2322.

[0075] The material of the support member 2322 is not particularly limited, but may be, for example, a metal such as steel or aluminum. Of these, steel is preferable because of its high rigidity and availability. In FIG. 11, the support member 2322 is a spherical member separate from the pressing member, but it may be a protrusion integrally formed with the pressing member.

[0076] The support members 2322 may be disposed at both longitudinal ends of the reflecting surface 112 of the mirror 110. As shown in Fig. 11, it is preferable that the support members 2322 are disposed so that one longitudinal end overlaps with the central axis Ax, and that the two support members 2322 are disposed so as to sandwich the central axis Ax at the other longitudinal end. This can further increase the rigidity of the optical mirror 100, and can further suppress the coincidence between the resonant frequency of the optical mirror 100 and the vibration of the image forming apparatus.

[0077] The fθ lens 233a is a so-called toroidal lens. The fθ lenses 233b, 233c, and 233e are spherical lenses. The fθ lens 233d is a cylindrical lens. Note that the scanning optical device 200 may use a scanning optical system that is a combination of other lenses and mirrors instead of these lenses and mirrors.

[0078] The optical deflector 220 has the polygon mirror 240, a box-shaped container 501, and a polygon motor substrate 502. The type of the polygon motor substrate 502 is not particularly limited, but is, for example, a glass epoxy substrate. The container 501 and the polygon motor substrate 502 form a casing 503 that houses the polygon mirror 240.

[0079] The polygon mirror 240 is a rotating polygonal mirror. A rotation shaft 241 of the polygon mirror 240 is fixed to the upper surface 223 of the container 501 using a fixing screw. The polygon mirror 240 is journaled on the rotation shaft 241 via an inner cylindrical bearing 504, and can rotate around the rotation shaft 241. A magnet 505 is attached to the lower end of the polygon mirror 240. In addition, a winding coil 506 is disposed on the polygon motor board 502 at a position facing the magnet 505. The magnet 505 and the winding coil 506 constitute a polygon motor, and drive the polygon mirror 240 to rotate.

[0080] The polygon motor substrate 502 further includes a control IC (Integrated Circuit) and a connector (not shown). The polygon motor substrate 502 is connected to the control unit 350 via the connector, and receives a supply of power and an input of a control signal. In response to the control signal, the control IC energizes the winding coil 506 to rotate the polygon mirror 240.

[0081] In this embodiment, the gap between the container 501 and the housing 230 is sealed by a flat glass 511. In addition, a heat insulating member 512 is disposed between the housing 230 and the polygon motor board 502. The flat glass 511 prevents foreign matter such as toner from moving between the inside and outside of the optical deflector 220 and adhering to the optical elements that constitute the scanning optical device 200. The flat glass 511 allows the light beam L to pass through.

[0082] The scanning optical device 200 having such a configuration can perform exposure scanning on the outer peripheral surface of the electrophotographic photosensitive member 315 by the following operation.

[0083] First, the light beam L is emitted from the light source 231, and the light beam L travels through the mirror 232a and the flat glass 511 into the optical deflector 220 and is incident on the polygon mirror 240 which is rotated. As a result, the reflection direction of the light beam L changes according to the rotation angle of the polygon mirror 240. The light beam L reflected by the polygon mirror 240 passes through the fθ lenses 233a, 233b, 233c, 233d, the mirrors 232b, 232c, 232d, and the fθ lens 233e in this order, and then passes through the emission part 234 and is emitted to the outside of the scanning optical device 200. The light beam L emitted to the outside of the scanning optical device 200 passes above the upper surface 223 of the optical deflector 220 and is incident on the outer circumferential surface of the electrophotographic photosensitive member 315. The light beam L is deflected in the main scanning direction while the light amount is modulated according to the image data. As a result, an electrostatic latent image is formed.

[0084] In this embodiment, a flat glass 513 is also disposed in the emission unit 234. As the flat glass 513, the same glass as the flat glass 511 can be used.

[0085] Next, the operation of the image forming apparatus 300 shown in FIG. 5 will be described. The original is read by the image reading unit 330 and becomes input image data. The input image data is subjected to predetermined image processing in an image processing unit (not shown) and is sent to the scanning optical device 200 via the control unit 350.

[0086] The electrophotographic photoreceptor 315 rotates at a constant peripheral speed. The charging device 316 uniformly charges the surface of the electrophotographic photoreceptor 315 to a negative polarity. In the scanning optical device 200, the polygon mirror of the polygon motor rotates at high speed, and laser light corresponding to the input image data of each color component is developed along the axial direction of the electrophotographic photoreceptor 315 and is irradiated onto the outer circumferential surface of the electrophotographic photoreceptor 315 along the axial direction. In this way, an electrostatic latent image is formed on the surface of the electrophotographic photoreceptor 315.

[0087] In the developing device 314, the toner base particles are charged by stirring and transporting the two-component developer in the developing container, and the two-component developer is transported to a developing roller, which forms a magnetic brush on the surface of the developing roller. The charged toner base particles electrostatically adhere from the magnetic brush to the electrostatic latent image on the electrophotographic photoreceptor 315. In this way, the electrostatic latent image on the surface of the electrophotographic photoreceptor 315 is visualized, and a toner image corresponding to the electrostatic latent image is formed on the surface of the electrophotographic photoreceptor 315. The term "toner image" refers to the state in which toner is gathered in an image shape.

[0088] The toner image on the surface of the electrophotographic photoreceptor 315 is transferred to an intermediate transfer belt 3121 by an intermediate transfer unit 312. Residual toner remaining on the surface of the electrophotographic photoreceptor 315 after transfer is removed by a drum cleaning device 317 having a drum cleaning blade that is in sliding contact with the surface of the electrophotographic photoreceptor 315.

[0089] The intermediate transfer belt 3121 is pressed against the electrophotographic photoreceptor 315 by the primary transfer roller 3122, whereby a primary transfer nip is formed for each electrophotographic photoreceptor by the electrophotographic photoreceptor 315 and the intermediate transfer belt 3121. In the primary transfer nip, toner images of each color are transferred to the intermediate transfer belt 3121 in order, superimposed thereon.

[0090] Meanwhile, secondary transfer roller 3131 is pressed against intermediate transfer belt 3121 and secondary transfer belt 3132. As a result, a secondary transfer nip is formed by intermediate transfer belt 3121 and secondary transfer belt 3132. Paper S passes through the secondary transfer nip. Paper S is transported to the secondary transfer nip by paper transport section 340. Correction of the inclination of paper S and adjustment of the transport timing are performed by a registration roller section in which registration roller pair 343a is arranged.

[0091] When the paper S is transported to the secondary transfer nip, a transfer bias is applied to the secondary transfer roller 3131. By applying this transfer bias, the toner image carried on the intermediate transfer belt 3121 is transferred to the paper S (a process of adhering the toner for developing an electrostatic image to a recording medium). The paper S to which the toner image has been transferred is transported by the secondary transfer belt 3132 toward the fixing device 320.

[0092] Any deposits such as residual toner remaining on the surface of the intermediate transfer belt 3121 after the secondary transfer are removed by a belt cleaning device 3126 having a cleaning blade that is in sliding contact with the surface of the intermediate transfer belt 3121. At this time, since the intermediate transfer body described above is used as the intermediate transfer belt, the dynamic frictional force can be reduced over time.

[0093] The fixing device 320 sandwiches the fixing belt between a rotating fixing roller and a pressure roller to form a fixing nip, and heats and presses the conveyed paper S in the fixing nip. In this way, the toner image is fixed to the paper S (a process of fixing the toner for developing an electrostatic image to a recording medium). The paper S with the fixed toner image is discharged outside the machine by a paper discharge section 342 equipped with a paper discharge roller 342a.

[0094] 2. Second embodiment 2-1.Optical mirror Fig. 12 is a plan view showing the adhesive surface 120a between the mirror 110 and the reinforcing member 120 and the adhesive layer 130 of the optical mirror 400 in the embodiment 2. As shown in Fig. 12, the embodiment 2 differs from the optical mirror 100 in the embodiment 1 in that the adhesive layer 130 is an adhesive layer in which a plurality of adhesive portions 131 are partially connected.

[0095] Since the adhesive layer 130 is an adhesive layer in which a plurality of adhesive portions 131 are partially connected, the resonance frequency of the third bending vibration and the resonance frequency of the torsional vibration of the optical mirror 400 can be made close to the values ​​when the adhesive layer 130 covers the entire surface of the adhesive surface 120a. When the adhesive layer 130 covers the entire surface of the adhesive surface 120a, resonance of the third bending vibration and resonance of the torsional vibration are unlikely to occur in the image forming apparatus. Therefore, the optical mirror 400 in this embodiment can reduce the burden on the worker caused by overflow of the adhesive during production while suppressing resonance of the third bending vibration and resonance of the torsional vibration.

[0096] If the reinforcing member is transparent, it is possible to visually check the shape of the adhesive layer whether the adhesive layer 130 is an adhesive layer formed by partially connecting a plurality of adhesive portions 131. If the reinforcing member is not transparent and cannot be visually determined, it is possible to check by peeling off the adhesive and visually checking the shape of the adhesive layer.

[0097] The total maximum length of the adhesive layer 130 in the longitudinal direction of the adhesive surface 120a is 40% or more, and preferably 60% or more, of the length of the adhesive surface 120a in the longitudinal direction (the direction of the arrow A in FIG. 12). The upper limit of the total length is, for example, 100% of the longitudinal length of the adhesive surface 120a.

[0098] The coverage area of ​​the adhesive layer 130 is preferably 30% or more and less than 100% of the area of ​​the adhesive surface 120a, and more preferably 50% or more and less than 100%.

[0099] 2-2. Manufacturing method of optical mirror In the method for manufacturing the optical mirror according to the first embodiment, the optical mirror 400 can be manufactured by adjusting the amount of adhesive applied and the application interval in the step of applying the adhesive.

[0100] The application interval of the adhesive is preferably equal to or less than 0.94 times the width of the substrate 111. This makes it easier for the multiple adhesive portions 131 to be partially connected when the mirror 110 and the reinforcing member 120 are bonded together. The lower limit of the application interval is, for example, 0 mm. EXAMPLES

[0101] The present invention will now be described with reference to examples, which should not be construed as limiting the scope of the present invention.

[0102] <Resonance frequency of primary bending vibration> The resonance frequency of the primary bending vibration was determined for each of the optical mirrors 1 to 8 that satisfied the conditions in Table 1 using simulation software (ANSYS 2023 R1, manufactured by ANSYS, Inc.). In the optical mirrors 1 to 8, the adhesive layer is configured with multiple adhesive parts formed by hardening the adhesive, which are arranged at intervals, and the intervals between the multiple adhesive parts are all equal. In addition, the cross section of each adhesive part parallel to the adhesive surface is a circle with a diameter of 14 mm.

[0103] For comparison, the above-mentioned resonance frequency was also obtained in the same manner for an optical mirror in which adhesive was applied to the entire bonding surface between the mirror and the reinforcing member. The ratio of the resonance frequency of optical mirrors 1 to 8, where the resonance frequency obtained here was taken as 100%, was obtained, and the relationship with the length of the adhesive layer is shown in FIG.

[0104] In the above simulation, the mirror and reinforcing members shown below were used, and the adhesive and supporting members were expressed by the settings of the simulation software. In the above simulation, the supporting members were arranged at both ends of the mirror in the longitudinal direction, one at one end and two at the other end, as shown in Figure 11. Mirror (thickness: 5.5 mm, length in the longitudinal direction: 233 mm, width: 15 mm, aspect ratio: 15.5) Reinforcing member (glass, thickness 3 mm, longitudinal length: 233 mm, width: 15 mm, aspect ratio: 15.5)

[0105] The adhesive was expressed by setting the connection between the substrate and the reinforcing member at the adhesive part as a bond (setting the surfaces not to shift). When applying the adhesive, the adhesive is pressed until the substrate and the reinforcing member come into contact, resulting in a thin layer of about 1 μm at its thinnest point, and this setting was adopted because deformation (shear deformation) of the adhesive can be ignored. For the support member, the displacement of the support member is fixed at the contact point between the support member and the substrate at one end (single-point holding side), and the displacement of the support member in the in-plane rotation and thickness / short-side direction is fixed at the contact point between the support member and the substrate at the other end (two-point holding side).

[0106] In addition, in Table 1, "longitudinal length of adhesive layer" refers to the total longitudinal length of the adhesive portion on the central axis extending in the longitudinal direction of the adhesive surface between the mirror and the reinforcing member.

[0107] [Table 1]

[0108] As shown in Fig. 13, when the length of the adhesive layer is 40% or more of the length of the mirror, the resonance frequency is less likely to vary due to the variation in the length of the adhesive layer. It was also found that when the length of the adhesive layer is 40% or more of the length of the mirror, the resonance frequency of the optical mirror approaches the resonance frequency when the adhesive layer covers the entire bonding surface between the mirror and the reinforcing member. The numbers 1 to 8 in the graph of Fig. 13 correspond to the optical mirrors 1 to 8, respectively.

[0109] <Resonance frequency of secondary bending vibration> The resonance frequency of the secondary bending vibration was determined for the optical mirrors 1 to 8 using the above simulation software. For comparison, the resonance frequency of the secondary bending vibration was determined in the same manner for an optical mirror in which adhesive was applied to the entire bonding surface between the mirror and the reinforcing member. The ratio of the resonance frequency of the optical mirrors 1 to 8 to the resonance frequency determined here as 100% was determined, and the relationship with the length of the adhesive layer is shown in FIG. 14.

[0110] As shown in Fig. 14, when the length of the adhesive layer is 60% or more of the length of the mirror, the resonance frequency of the secondary bending vibration is less likely to vary due to the variation in the length of the adhesive layer. It was also found that when the length of the adhesive layer is 60% or more of the length of the mirror, the resonance frequency of the secondary bending vibration of the optical mirror approaches the resonance frequency of the secondary bending vibration when the entire bonding surface between the mirror and the reinforcing member is covered with the adhesive layer. The numbers 1 to 8 in the graph of Fig. 14 correspond to the optical mirrors 1 to 8, respectively.

[0111] <Resonance frequencies of third-order bending vibration and torsional vibration> The resonance frequency of the third bending vibration and the resonance frequency of the torsional vibration were obtained for the optical mirror 9 having an adhesive layer in which multiple adhesive layers are partially connected, using the above simulation software. The conditions of the mirror, reinforcing member, adhesive, and support member are the same as those of the optical mirrors 1 to 8. The longitudinal length of the adhesive layer of the optical mirror 9 is 100% of the longitudinal length of the mirror.

[0112] For comparison, the resonant frequency of the third bending vibration and the resonant frequency of the torsional vibration were determined in the same manner for an optical mirror in which adhesive was applied to the entire bonding surface between the mirror body (main body portion) and the reinforcing member.

[0113] The ratio of the resonant frequency of the tertiary bending vibration of optical mirror 9 to the resonant frequency of the tertiary bending vibration of an optical mirror in which adhesive is applied to the entire bonding surface with the reinforcing member was 99.97%. Also, the ratio of the resonant frequency of the torsional vibration of optical mirror 9 to the resonant frequency of the torsional vibration of an optical mirror in which adhesive is applied to the entire bonding surface with the reinforcing member was 99.67%.

[0114] <Effect of adhesive spacing> The resonance frequency of the primary bending vibration was obtained for the optical mirror 10 and the optical mirror 11 using the above simulation software. The optical mirror 10 has a plurality of adhesive parts formed by hardening the adhesive arranged at equal intervals (see FIG. 2). The optical mirror 11 has a plurality of the above adhesive parts arranged at non-equidistant intervals (see FIG. 15). The longitudinal length of the adhesive layer of both the optical mirror 10 and the optical mirror 11 is 66% of the longitudinal length of the mirror. The ratio of the resonance frequency of the optical mirror 10 to the resonance frequency of an optical mirror in which the adhesive is applied to the entire surface of the adhesive surface to the reinforcing member was 99.9%. On the other hand, the above ratio for the optical mirror 11 was 99.7%. [Industrial Applicability]

[0115] The optical mirror according to the present invention can suppress resonance in an image forming apparatus, and is therefore useful in the field of image forming. [Explanation of symbols]

[0116] 100, 400 Optical mirror 110 Mirror 111 Substrate 112 Reflective surface 120 Reinforcement member 120a Adhesive surface 130 Adhesive layer 131 Adhesive part 200 Scanning optical device 210 Bulkhead 220 Optical deflector 230 Housing 240 Polygon Mirror 300 Image forming device 310 Image forming section 320 Fixing device 330 Image reading unit 340 Paper transport section

Claims

1. An elongated optical mirror, a mirror including a substrate and a reflective surface formed on one end surface in a thickness direction of the substrate; a reinforcing member having an elongated shape and bonded to a surface of the mirror opposite to the reflecting surface; an adhesive layer disposed between the mirror and the stiffening member; the adhesive layer partially covers an adhesive surface between the mirror and the reinforcing member; In the longitudinal direction of the adhesive surface, the total maximum length of the adhesive layer in the longitudinal direction is 40% or more of the length of the adhesive surface in the longitudinal direction. Optical mirror.

2. a total length of the adhesive layer in the longitudinal direction on a central axis extending in the longitudinal direction of the adhesive surface is 60% or more of a length of the mirror in the longitudinal direction; 2. The optical mirror according to claim 1.

3. The adhesive layer is composed of a plurality of adhesive portions.

2. The optical mirror according to claim 1.

4. The adhesive portions are arranged at equal intervals.

4. The optical mirror according to claim 3.

5. The adhesive layer is an adhesive layer formed by partially connecting a plurality of adhesive portions.

2. The optical mirror according to claim 1.

6. 2. The optical mirror of claim 1, wherein the reinforcing member is made of glass.

7. The reinforcing member has a thickness smaller than that of the mirror and has an unpolished surface.

7. The optical mirror according to claim 6.

8. The material type of the substrate of the mirror and the material type of the reinforcing member are the same.

7. The optical mirror according to claim 6.

9. The adhesive layer is an adhesive layer formed by curing an ultraviolet curing adhesive.

2. The optical mirror according to claim 1.

10. The mirror and the reinforcing member have the same length in the longitudinal direction and the same width.

2. The optical mirror according to claim 1.

11. A scanning optical device comprising an optical mirror according to any one of claims 1 to 12.

12. a pressing member for pressing the reinforcing member of the optical mirror toward the mirror side; 12. The scanning optical device according to claim 11.

13. the optical mirror further includes support members disposed at both ends of the reflecting surface of the optical mirror in a longitudinal direction thereof for supporting the mirror from the reflecting surface side; the adhesive layer of the optical mirror is disposed so that at least a portion of the adhesive layer overlaps a position where the support member is disposed in a plan view seen from the reflecting surface side; 12. The scanning optical device according to claim 11.

14. An image forming apparatus comprising the scanning optical device according to claim 11.

15. applying an adhesive to a surface of a mirror opposite to a reflective surface at a plurality of spaced locations; attaching a reinforcing member to the adhesive-coated surface of the mirror; bonding the mirror and the reinforcing member; A method for manufacturing an optical mirror, comprising:

16. The method for manufacturing an optical mirror according to claim 15 , wherein the adhesive is spot-applied in the applying step.

17. The adhesive is an ultraviolet curing adhesive, In the bonding step, the mirror and the reinforcing member are placed in an ultraviolet irradiation furnace to harden the adhesive and bond the mirror and the reinforcing member to each other. The method for manufacturing an optical mirror according to claim 15 or 16.

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