Optical scanning apparatus and image forming apparatus

Abstract

To provide an optical scanning device that can accurately adjust lens distortion with a simple configuration. [Solution] The optical scanning device comprises an fθ lens for focusing light onto an object to be irradiated, a housing section having an opening for housing the fθ lens, a cover section that closes the opening of the housing section and allows light emitted from the fθ lens to pass through, and an adjustment section that adjusts the amount of rotation of the fθ lens around a pivot axis extending along the thickness direction of the fθ lens. The adjustment section includes a head protruding outward from the side wall of the housing section and a screw section extending from the head along a first direction toward the fθ lens through the side wall, and has a male screw member that rotates the fθ lens by moving the tip of the screw section along the first direction in response to the rotation of the head. The cover section protrudes so as to abut against the outer circumference of the head and has an arm section that generates a click sensation in the head in response to the rotation of the head.

Description

Technical Field

[0001] The present invention relates to an optical scanning device and an image forming device.

Background Art

[0002] An optical scanning device provided with an adjustment member for adjusting the distortion of an fθ lens has been proposed (for example, Patent Document 1). In the optical scanning device disclosed in Patent Document 1, the adjustment member includes a rotation locking member that can lock a male screw member at each predetermined rotation angle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-mentioned Patent Document 1, in order to lock the male screw member at each predetermined rotation angle, a separate rotation locking member is required. Therefore, the number of parts increases and the configuration of the optical scanning device becomes complicated.

[0005] An object of the present disclosure is to provide an optical scanning device and an image forming device that can accurately adjust the distortion of a lens with a simple configuration.

Means for Solving the Problems

[0006] An optical scanning device according to one aspect of the present disclosure includes an fθ lens for focusing light onto an object to be illuminated; a housing portion having an opening for housing the fθ lens; a cover portion that closes the opening of the housing portion and transmits the light emitted from the fθ lens; and an adjustment portion for adjusting the amount of rotation of the fθ lens around a pivot axis extending along the thickness direction of the fθ lens. The adjustment portion includes a head portion that protrudes outward from the side wall of the housing portion, and a screw portion that extends from the head portion through the side wall toward the fθ lens in a first direction, and has a male screw member that rotates the fθ lens by moving the tip of the screw portion toward the first direction in response to the rotation of the head. The cover portion has an arm portion that protrudes so as to abut against the outer circumference of the head portion and generates a click sensation in the head portion in response to the rotation of the head portion.

[0007] An image forming apparatus according to one aspect of the present disclosure comprises an fθ lens for focusing light onto an object to be illuminated; a housing portion having an opening for housing the fθ lens; a cover portion that closes the opening of the housing portion and transmits the light emitted from the fθ lens; and an adjustment portion for adjusting the amount of rotation of the fθ lens about a pivot axis extending along the thickness direction of the fθ lens, wherein the adjustment portion includes a head protruding outward from the side wall of the housing portion and a screw portion extending from the head through the side wall toward the fθ lens, and has a male screw member that rotates the fθ lens by the movement of the tip of the screw portion toward the first direction in response to the rotation of the head, and the cover portion has an arm portion that protrudes so as to abut against the outer circumference of the head and generates a click sensation in the head in response to the rotation of the head. [Effects of the Invention]

[0008] According to this disclosure, the optical scanning apparatus and the image forming apparatus have the effect of being able to adjust lens distortion with high precision using a simple configuration. [Brief explanation of the drawing]

[0009] [Figure 1]This is a schematic cross-sectional view showing the configuration of an image forming apparatus equipped with an optical scanning device according to an embodiment of the present disclosure. [Figure 2] This is a schematic plan view showing an example of an optical scanning apparatus according to an embodiment of the present disclosure. [Figure 3] Figure 2 is a perspective view showing an example of the connection between the top cover and the housing of the optical scanning device. [Figure 4] Figure 2 is a perspective view showing the optical scanning device with the top cover removed. [Figure 5] Figure 4 is a cross-sectional view of the optical scanning device shown in VV. [Figure 6] Figure 2 is a plan view showing an enlarged view of the adjustment section of the optical scanning device. [Figure 7] This is a plan view showing the second fθ lens of the optical scanning device according to the embodiment of this disclosure in a first adjustment position. [Figure 8] This is a plan view showing the second fθ lens of the optical scanning device according to the embodiment of this disclosure in a second adjustment position. [Figure 9] This figure shows an example of the change in the positional relationship between the head of the adjustment member and the arm portion of the optical scanning device according to the embodiment of this disclosure. [Figure 10] This figure shows an example of a change in the positional relationship between the head and arm portion of the adjustment member of an optical scanning device according to a first modified embodiment of the present disclosure. [Figure 11] This figure shows an example of the positional relationship between the head and arm portion of an adjustment member in an optical scanning device according to a first modified embodiment of the present disclosure. [Figure 12] This figure shows an example of a change in the positional relationship between the head and arm portions of the adjustment member in an optical scanning device according to a second modified embodiment of the present disclosure. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments and modifications of the present disclosure will be described with reference to the drawings. In the following, the same or corresponding members are denoted by the same reference numerals throughout all the drawings, and redundant descriptions thereof are omitted. Further, the embodiments and modifications described below are merely examples of the present disclosure, and the present disclosure is not limited to the embodiments and modifications. Even outside these embodiments and modifications, various changes can be made according to the design and the like as long as the technical idea of the present disclosure is not deviated from.

[0011] (Image forming apparatus) FIG. 1 is a cross-sectional view schematically showing the configuration of an image forming apparatus 1 including an optical scanning device 100 according to an embodiment of the present disclosure. In the figure, the direction orthogonal to the main scanning direction X is defined as the width direction Y (sub-scanning direction), and the direction orthogonal to the main scanning direction X and the width direction Y is defined as the vertical direction Z, and the following description will be made.

[0012] The image data handled in the image forming apparatus 1 corresponds to a color image using each color of black (K), cyan (C), magenta (M), and yellow (Y) or a monochrome image using a single color (for example, black). Therefore, four developing devices 12, four photosensitive drums 13, four drum cleaning devices 14, and four chargers 15 are provided respectively to form four types of toner images corresponding to each color. And each of the developing device 12, the photosensitive drum 13 (irradiated body), the drum cleaning device 14, and the charger 15 is associated with black, cyan, magenta, and yellow, and constitutes four image stations Pa, Pb, Pc, and Pd.

[0013] In each of the image stations Pa, Pb, Pc, and Pd, after the residual toner on the surface of the photosensitive drum 13 is removed and recovered by the drum cleaning device 14, the surface of the photosensitive drum 13 is uniformly charged to a predetermined potential by the charger 15.

[0014] The optical scanning device 100 exposes the surface of the photosensitive drum 13 and forms an electrostatic latent image on the surface of the photosensitive drum 13.

[0015] The developing device 12 develops the electrostatic latent image on the surface of the photosensitive drum 13 to form a toner image on the surface of the photosensitive drum 13. Thereby, toner images of respective colors are formed on the surface of each photosensitive drum 13.

[0016] Next, while the intermediate transfer belt 21 is circulated and moved, the residual toner on the intermediate transfer belt 21 is removed and collected by the belt cleaning device 22. Thereafter, the toner images of respective colors on the surface of each photosensitive drum 13 are sequentially transferred onto the intermediate transfer belt 21 and overlapped to form a color toner image on the intermediate transfer belt 21.

[0017] A nip area is formed between the intermediate transfer belt 21 and the transfer roller 23a of the secondary transfer device 23. The recording paper conveyed through the paper conveyance path 31 is sandwiched in that nip area, and the color toner image on the surface of the intermediate transfer belt 21 is transferred onto the recording paper. Then, the recording paper is sandwiched between the heating roller 24 and the pressure roller 25 of the fixing device 17 and heated and pressed to fix the color toner image on the recording paper.

[0018] The recording paper is stored in the paper feed cassette 18. The recording paper is sent out from the paper feed cassette 18 to the paper conveyance path 31 by the pickup roller 33. The recording paper is conveyed through the paper conveyance path 31, passes through the secondary transfer device 23 and the fixing device 17, and heads toward the paper discharge roller 36. Then, the recording paper is discharged to the paper discharge tray 39 by the paper discharge roller 36.

[0019] Note that a plurality of conveying rollers 35 are arranged at a plurality of locations in the paper conveyance path 31. The conveying roller 35 conveys the recording paper in the paper conveyance path 31.

[0020] Furthermore, a registration roller 34 is arranged in the paper conveyance path 31. The registration roller 34 temporarily stops the recording paper, aligns the leading edges of the recording paper, and then starts the conveyance of the recording paper in accordance with the transfer timing of the toner image in the nip area between the intermediate transfer belt 21 and the transfer roller 23a.

[0021] (Optical Scanning Device) Next, an example of the optical scanning apparatus 100 according to the embodiment of this disclosure will be described below with reference to Figures 2 to 5.

[0022] Figure 2 is a schematic plan view showing an example of an optical scanning apparatus 100 according to an embodiment of this disclosure. Figure 3 is a perspective view showing an example of the joining state between the top cover 121 (cover portion) and the housing 120 (housing portion) of the optical scanning apparatus 100 shown in Figure 2. In the perspective view shown in Figure 3, a part of the optical scanning apparatus 100 is shown for the convenience of explanation. Figure 4 is a perspective view showing the optical scanning apparatus 100 shown in Figure 2 with the top cover 121 removed. Figure 4 shows the state when the optical scanning apparatus 100 is viewed from diagonally above the front side of the image forming apparatus 1. Figure 5 is a VV cross-sectional view of the optical scanning apparatus 100 shown in Figure 4.

[0023] As shown in Figure 2, the optical scanning device 100 comprises a rectangular top cover 121 and a housing 120.

[0024] The top cover 121 can be made of a highly flexible resin material such as acrylonitrile butadiene styrene resin (ABS resin) or high-impact polystyrene resin (HI-PS resin). As shown in Figure 3, the top cover 121 comprises a top cover surface 121b that closes the opening on the top surface of the housing 120 and a top cover side surface 121c (cover side surface) that is connected to the edge of the top cover surface 121b and is erected in the Z direction from the edge of the top cover surface 121b. The top cover side surface 121c extends along the side wall of the housing 120.

[0025] The top cover surface 121b has a rectangular shape, and the top cover side surfaces 121c are connected to the edges of opposing sides of the top cover surface 121b in the X direction. The top cover 121 engages with the housing 120 via the top cover side surfaces 121c.

[0026] As shown in Figures 2 and 3, the top cover 121 has four dustproof windows 121a formed therein, each allowing the light beam L (light) emitted from the second fθ lens 110 (fθ lens) to pass through. The dustproof windows 121a are made of, for example, transparent glass. The top cover 121 has four openings, and each dustproof window 121a closes off its respective opening. The light beam L that passes through each dustproof window 121a is imaged onto each photoreceptor drum 13.

[0027] The housing 120 can be made of a resin material with high strength and dimensional stability, such as glass fiber reinforced polycarbonate ABS resin, or a metal material such as aluminum. As shown in Figure 4, the housing 120 has a rectangular bottom plate 122 and four side walls 123a to 123d surrounding the bottom plate 122. The side walls 123a to 123d are the front, rear, left, and right side walls, respectively. The top of the housing 120 is open. The top cover 121 closes the opening of the housing 120 and prevents dust from entering.

[0028] As shown in Figure 2, the optical scanning device 100 guides the light beam L emitted from each of the multiple light-emitting elements 151, such as semiconductor lasers, to the reflective surface of a deflector 140, such as a polygon mirror. The optical scanning device 100 then deflects the light beam L by reflecting it off the reflective surface of the deflector 140.

[0029] The light beam L reflected by the deflector 140 is guided by each optical component located within the housing 120 to each of the multiple photoreceptor drums 13 that are to be scanned. In this way, the optical scanning device 100 scans each corresponding photoreceptor drum 13 with the light beam L.

[0030] More specifically, the optical path from each light-emitting element 151 to the deflector 140 includes four collimator lenses 152, four first mirrors 153, a cylindrical lens 154, and a second mirror 155. Of the four first mirrors 153, one will be referred to as first mirror 153a, and the remaining three will be referred to as first mirrors 153b for distinction and explanation.

[0031] Each collimator lens 152 converts each light beam L emitted from each light-emitting element 151 into parallel light. Each of the light beams L converted into parallel light is then guided to each first mirror 153.

[0032] First, each of the three first mirrors 153b reflects the light beam L incident from each of the three light-emitting elements 151 through the respective collimator lenses 152 to one of the first mirrors 153a. Then, the one first mirror 153a reflects each of the light beams L reflected by each of the three first mirrors 153b to the cylindrical lens 154.

[0033] Furthermore, the light beam L that passes through the collimator lens 152 from the remaining one of the four light-emitting elements 151 passes over the first mirror 153a and enters the cylindrical lens 154.

[0034] The cylindrical lens 154 focuses the light beam L only in the width direction and concentrates it on the reflective surface of the deflector 140 via the second mirror 155. The deflector 140 rotates at high speed around the rotation axis G, and reflects each of the light beams L at each reflective surface, repeatedly deflecting them in the main scanning direction X.

[0035] As shown in Figure 5, in the optical scanning device 100, a first fθ lens 170, multiple reflective mirrors 161-168, and multiple (four in this example) second fθ lenses 110 (fθ lenses) are arranged in the optical path from the deflector 140 to each photoreceptor drum 13. The device is configured so that each of the light beams L deflected by the deflector 140 is guided to each photoreceptor drum 13.

[0036] The first fθ lens 170 is made of a resin material and extends in the main scanning direction X. The first fθ lens 170 focuses the light beam L to a predetermined beam diameter on the surface of the photoreceptor drum 13 and emits it. The first fθ lens 170 also converts the light beam L, which is deflected by the deflector 140 with constant velocity rotational motion in the main scanning direction X, so that it is scanned at a constant velocity along the main scanning line on each photoreceptor drum 13.

[0037] Multiple reflective mirrors 161-168 reflect the light beam L that has passed through the first fθ lens 170 towards each of the multiple second fθ lenses 110.

[0038] The second fθ lens 110 is made of a resin material and extends in the main scanning direction X. The second fθ lens 110 mainly focuses the parallel light beam L in the sub-scanning direction and narrows it to a predetermined beam diameter (spot diameter) on the surface of each photoreceptor drum 13. Then, in the main scanning direction X, the second fθ lens 110 emits the focused light beam L to each photoreceptor drum 13.

[0039] As described above, in the optical scanning device 100, the light beam L is reflected and deflected by the reflective surface of the deflector 140 and incident on the photoreceptor drum 13. The photoreceptor drum 13 is rotated, and the surface (circumferential surface) of the photoreceptor drum 13 is scanned by the light beam L, and an electrostatic latent image is formed on the surface of the photoreceptor drum 13.

[0040] The optical scanning device 100 having the above-described configuration includes an adjustment unit 180, as shown in Figure 4, which adjusts the amount of rotation that rotates the second fθ lens 110 around a pivot axis α along the thickness direction (vertical direction Z) of the second fθ lens 110, in other words, around a pivot axis α along the optical axis of the light emitted from the second fθ lens 110. The amount of rotation is the angle by which the second fθ lens 11 is rotated around the pivot axis α. The pivot axis α is set at one end of the long second fθ lens 110.

[0041] (adjustment section) In the following description, the configuration of the adjustment unit 180 provided in the optical scanning device 100 will be explained with reference to Figures 6 to 8.

[0042] The adjustment unit 180 adjusts the irradiation position of the light beam L emitted from the second fθ lens 110 on the photoreceptor drum 13 by rotating the second fθ lens 110 around the pivot axis α. By adjusting the irradiation position of the light beam L on the photoreceptor drum 13 in this way, color misalignment of the color toner image formed on the recording paper can be corrected.

[0043] Figure 6 is a plan view showing an enlarged view of the adjustment section 180 of the optical scanning device 100 shown in Figure 2. Figure 7 is a plan view showing the second fθ lens 110 of the optical scanning device 100 according to the embodiment of this disclosure in the first adjustment position. Figure 8 is a plan view showing the second fθ lens 110 of the optical scanning device 100 according to the embodiment of this disclosure in the second adjustment position.

[0044] The optical scanning device 100 is equipped with four adjustment units 180, corresponding to the four photoreceptor drums 13. Each of the four adjustment units 180 has the same configuration.

[0045] Here, as shown in Figure 6, the straight line passing through the center of the second fθ lens 110 in the width direction and extending along the longitudinal direction is referred to as the longitudinal axis γ. Furthermore, when the second fθ lens 110 is located at a predetermined reference position, the imaginary straight line passing through the center of the second fθ lens 110 in the width direction (short direction) and extending along the longitudinal direction is referred to as the reference imaginary line β. That is, when the second fθ lens 110 is located at a predetermined reference position, the longitudinal axis γ and the reference imaginary line β coincide.

[0046] On the other hand, the first adjustment position shown in Figure 7 and the second adjustment position shown in Figure 8 are rotated around the pivot axis α by the adjustment unit 180, and represent a state in which the longitudinal axis γ of the second fθ lens 110 is shifted from the reference virtual straight line β.

[0047] Here, the direction in which the second fθ lens 110 rotates due to the adjustment unit 180 is defined as the rotation direction C. The rotation angle φ of the second fθ lens 110 represents the angle of the longitudinal axis γ of the second fθ lens 110 with respect to the reference virtual line β. The rotation angle φ of the second fθ lens 110 is not particularly limited, but for example, it can be shown to be in the range of 30 to 50 degrees.

[0048] In the optical scanning device 100, as shown in Figures 6 to 8, the adjustment unit 180 includes a holding member 181, an inclined portion 182, a biasing member 188, and an adjustment member 183.

[0049] The retaining member 181 holds the second fθ lens 110 within the housing 120. The retaining member 181 is rotatable within the housing 120 around a pivot axis α, and the rotation of the retaining member 181 allows the second fθ lens 110 to rotate. The retaining member 181 has an elongated shape that extends along the longitudinal direction of the second fθ lens 110.

[0050] The retaining member 181 is a plate-shaped sheet metal member and has a bottom plate 181a, a first side plate 181b, and a second side plate 181c. The first side plate 181b and the second side plate 181c are connected to both ends of the bottom plate 181a in the width direction, respectively, and are erected from the bottom plate 181a.

[0051] A second fθ lens 110 is positioned on the upper surface of the base plate 181a. An aperture (not shown) is provided in the portion of the base plate 181a through which the light beam L passes.

[0052] On the side of the bottom plate 181a where the first side plate 181b is provided, an inclined portion 182 is integrally formed with the retaining member 181.

[0053] The inclined portion 182 is provided at the end of the holding member 181 opposite to the side where the pivot axis α is set in the longitudinal direction. In a plan view, the inclined portion 182 is provided so as to protrude laterally from the holding member 181. The inclined portion 182 has an inclined surface 182a that extends in a direction intersecting the reference virtual line β.

[0054] The adjustment member 183 comes into contact with the inclined surface 182a of the inclined portion 182, thereby allowing the holding member 181 to rotate around the pivot axis α.

[0055] Furthermore, the adjustment section 180 has a biasing member 188 on the side opposite to the side where the inclined portion 182 is provided, in the width direction of the holding member 181.

[0056] The biasing member 188 biases the end of the retaining member 181 opposite to the side where the pivot axis α is provided, in the longitudinal direction of the retaining member 181, toward the adjusting member 183. The biasing member 188 can be, for example, a compression spring. The biasing member 188 is provided inside the housing 120 so as to press the retaining member 181 toward the adjusting member 183.

[0057] Thus, the holding member 181 is biased toward the adjustment member 183 by the biasing member 188. Therefore, when the adjustment member 183 moves in a direction that presses against the inclined surface 182a, the holding member 181 can be rotated counterclockwise around the pivot axis α in a plan view against the biasing force of the biasing member 188. On the other hand, when the adjustment member 183 moves away from the inclined surface 182a, the holding member 181 can be rotated clockwise around the pivot axis α in a plan view due to the biasing force of the biasing member 188.

[0058] The adjustment member 183 directly presses the inclined surface 182a of the inclined portion 182 along the intersecting direction (main scanning direction X in this example) that intersects with the inclined surface 182a, thereby rotating the holding member 181 together with the second fθ lens 110 around the pivot axis α.

[0059] In other words, the adjustment section 180 is configured such that the adjustment member 183 moves in a direction that presses against the inclined section 182, or moves in a direction that moves away from the inclined section 182, thereby rotating the second fθ lens 110 via the holding member 181. However, it is also possible to configure the adjustment member 183 to directly rotate the second fθ lens 110 without providing the holding member 181.

[0060] However, a configuration in which the second fθ lens 110 is rotated via the holding member 181, as in the adjustment member 183 of this embodiment, can avoid localized stress concentration on the second fθ lens 110. Therefore, it is preferable in that it can prevent distortion of the second fθ lens 110.

[0061] (Adjustment component) Next, the configuration of the adjustment member 183 will be described in more detail with reference to Figures 6 to 8.

[0062] The adjustment member 183 is a male screw member having a head 183a and a threaded portion 183b. The head 183a protrudes from the side wall 123a of the housing 120 to the outside of the housing 120.

[0063] The head portion 183a is a columnar member and has at least one convex portion and one or more flat portions on its side surface. In this embodiment, the head portion 183a of the adjustment member 183 has a regular polygonal outer shape when viewed from above, and the convex portion is realized by the corners of the regular polygon.

[0064] The head unit 183a functions as a drive unit that rotates the adjustment member 183 using a tool such as a screwdriver.

[0065] The threaded portion 183b is a cylindrical member extending from the head 183a, with helical threads formed on its circumferential surface. The housing 120 is provided with a female threaded member 186 having threads formed on the inner circumference of the hole. The threaded portion 183b screws into the female threaded member 186 provided on the housing 120 to support the adjustment member 183.

[0066] The threaded portion 183b extends from the head 183a through the side wall 123a along the X direction (first direction) toward the second fθ lens 110. More precisely, the threaded portion 183b extends along the first direction toward the inclined portion 182 provided on the retaining member 181 that holds the second fθ lens 110. Then, in accordance with the rotation of the head 183a, the tip of the threaded portion 183b moves along the first direction in a direction that presses against the inclined portion 182 or moves away from the inclined portion 182. This movement of the tip of the threaded portion 183b allows the retaining member 181 that holds the second fθ lens 110 to be rotated.

[0067] Incidentally, in the optical scanning device 100, the head portion 183a of the adjustment member 183 is rotated in order to adjust the distortion of the second fθ lens 110. In other words, the angle by which the second fθ lens 110 is rotated around the pivot axis α can be adjusted according to the direction and amount of rotation of the head portion 183a. For this reason, in order for the user to easily grasp the amount of rotation of the head portion 183a, a click sensation is generated in the head portion 183a each time it rotates by a predetermined angle. The mechanism for generating a click sensation in the head portion 183a will be described below.

[0068] (Mechanism that generates a clicking sensation) Referring to Figures 3 and 9, a mechanism for generating a click sensation in the head portion 183a of the optical scanning device 100 will be described. Figure 9 is a diagram showing an example of the change in the positional relationship between the head portion 183a and the arm portion 121d of the adjustment member 183 provided in the optical scanning device 100 according to the embodiment of this disclosure. Figure 9 shows the change in the positional relationship between the head portion 183a and the arm portion 121d each time the head portion 183a is rotated by 30 degrees.

[0069] Furthermore, the head 183a according to the embodiment of this disclosure will be described using the case where the outer shape of the head 183a is a regular hexagon when viewed from above as an example. Also, for the sake of convenience of explanation, the case where the head 183a is rotated clockwise in a plan view will be described as an example.

[0070] As shown in Figures 3 and 9, the top cover 121 is provided with an arm portion 121d consisting of protrusions 121d1 and 121d2 that extend along the top cover side surface 121c and project toward the head 183a of the adjustment member 183. When the end of each protrusion 121d1 and protrusion 121d2 on the top cover side surface 121c is considered the base end and the end opposite the base end is considered the tip, the base end is the fixed end and the tip is the free end. Furthermore, the protrusions 121d1 and 121d2 are displaceable in the left-right direction (Y direction).

[0071] In this configuration, the head 183a is initially positioned such that a pair of opposing edges (planes) extend in the vertical direction (Z direction).

[0072] When the head 183a is in its initial position, the protrusions 121d1 and 121d2 of the arm portion 121d each extend straight from the upper cover side surface 121c in the vertical direction (Z direction) toward the head 183a. The protrusions 121d1 and 121d2 are provided so as to contact the head 183a with each of the two sides that form a pair of edges extending in the vertical direction (Z direction) of the head 183a in a plan view, thereby sandwiching the head 183a.

[0073] When the head 183a is rotated 30 degrees clockwise from its initial position, the corner of the head 183a comes into contact with the arm 121d. On the arm 121d, the protrusions 121d1 and 121d2 are displaced in the left-right direction (Y direction) by the force exerted by the corner of the head 183a, with the former moving to the left and the latter to the right. At this time, the force exerted on the head 183a from the displaced arm 121d is greater than the force exerted on the head 183a from the arm 121d when the head 183a is in its initial position. Therefore, when the head 183a is rotated 30 degrees from its initial position, the load on the head 183a during its rotation increases. In other words, when rotating the head 183a, a large force is required because, when rotating the head 183a 30 degrees clockwise from its initial position, a force is needed to spread the arm 121d against the biasing force in the inward direction (towards the head 183a) of the arm 121d.

[0074] When the head 183a is further rotated clockwise to a position 60 degrees from its initial position, the protrusions 121d1 and 121d2 of the arm 121d are displaced from a state of bending to spread out in the left-right direction (Y direction) back to their original state before deformation, and the head 183a is locked in place, being held between the protrusions 121d1 and 121d2. At this time, the force exerted on the head 183a from the arm 121d is smaller than the force exerted on the head 183a from the arm 121d when the head 183a is 30 degrees from its initial position. Therefore, when the head 183a rotates from 30 degrees to 60 degrees, the load on the head 183a during rotation is reduced. In other words, when rotating the head 183a, the load is smaller than when rotating it 60 degrees clockwise from a position where it has been rotated 30 degrees. This is because the biasing force of the arm portion 121d in the inward direction (towards the head 183a) pushes the corner of the head 183a against the arm portion 121d, causing the head 183a to rotate clockwise. However, when the rotation exceeds 60 degrees, the load becomes large again.

[0075] In this way, the rotation of the head 183a changes the state from one where the corner of the head 183a is in contact with the arm 121d to one where the edge of the head 183a is in contact with the arm 121d. The resulting change in the magnitude of the force applied from the arm 121d to the head 183a changes the load applied to the head 183a during its rotation, thereby generating a clicking sensation in the head 183a.

[0076] In other words, the rotation of the head 183a causes the corner of the head 183a to come into contact with the arm 121d, deforming the arm 121d. When the arm 121d returns to its original state before deformation, the magnitude of the force applied from the arm 121d to the head 183a changes, which alters the load on the head 183a during rotation. This change allows a clicking sensation to be generated in the head 183a.

[0077] Therefore, the optical scanning device 100 can lock the head 183a in place by generating a click sensation every 60 degrees of rotation. As a result, the user can easily grasp the amount of rotation of the second fθ lens 110, which rotates in conjunction with the amount of rotation of the head 183a. Furthermore, the optical scanning device 100 does not require any separate component to generate a click sensation in the head 183a.

[0078] Therefore, the optical scanning device 100 can accurately adjust lens distortion with a simple configuration.

[0079] The optical scanning device 100 was configured to generate a click sensation in the head 183a every 60 degrees of rotation, but it is not limited to this configuration. For example, if the outer shape of the head 183a is changed from a regular hexagon to a regular dodecagon, the device can be configured to generate a click sensation in the head 183a every 30 degrees of rotation.

[0080] In the optical scanning device 100, the head 183a of the adjustment member 183 had a regular polygonal outer shape (a regular hexagon in the example shown in Figure 9), but it is not limited to this. For example, the head 183a may be circular, with protrusions provided at predetermined intervals on its side surface. In this configuration, where protrusions are provided at predetermined intervals on the side surface of the head 183a, the rotation of the head 183a is stably stopped when two of the multiple protrusions are in contact with the arm portion 121d. Also, when only one of the multiple protrusions is in contact with the arm portion 121d, the head 183a can be easily rotated clockwise or counterclockwise.

[0081] (First variation) Next, the configuration of the optical scanning device 100 according to a first modified example of the embodiment of this disclosure will be described with reference to Figure 10. Figure 10 is a diagram showing an example of the change in the positional relationship between the head 183a and the arm portion 121d of the adjustment member 183 provided in the optical scanning device 100 according to a first modified example of the embodiment of this disclosure. Figure 10 shows the change in the positional relationship between the head 183a and the arm portion 121d each time the head 183a is rotated by 15 degrees.

[0082] Furthermore, the head 183a in the first modified embodiment of this disclosure will be described using the case where the outer shape of the head 183a is a regular hexagon when viewed from above. Also, for the sake of convenience of explanation, the case where the head 183a is rotated clockwise in a plan view will be described using this as an example.

[0083] The optical scanning device 100 according to the first modified embodiment of the present disclosure differs from the optical scanning device 100 according to the embodiment of the present disclosure in the following respects. Specifically, the protrusions 121d1 and 121d2 of the arm portion 121d are provided at predetermined intervals on the inner surface of the side that contacts the head portion 183a, with a plurality of recesses 121e that engage with the corners of the head portion 183a.

[0084] In other words, on the inner surfaces of the protrusions 121d1 and 121d2, a plurality of recesses 121e are continuously provided along the longitudinal direction of the respective protrusions 121d1 and 121d2.

[0085] With respect to other configurations, the optical scanning device 100 according to the embodiment of this disclosure and the optical scanning device 100 according to the first modified example of the embodiment of this disclosure are the same.

[0086] As shown in Figure 10, when the head 183a is rotated 15 degrees clockwise from its initial position, the corners of the head 183a come into contact with the projections 121d1 and 121d2 respectively, and then fit into the recesses 121e provided on the projections 121d1 and 121d2, respectively, and the head 183a is locked in place.

[0087] Of the protrusions 121d1 and 121d2, the corner of the head 183a is fitted into the recess 121e located at the lowest part of the protrusion 121d1 on the left side. Also, the corner of the head 183a is fitted into the recess 121e located at the highest part of the protrusion 121d2 on the right side.

[0088] In other words, when the head 183a is rotated 15 degrees from its initial position, the corners of the head 183a come into contact with the projections 121d1 and 121d2, respectively, and then engage with the recesses 121e. That is, when the head 183a is rotated from its initial position, the corners of the head 183a come into contact with the projections 121d1 and 121d2, respectively. The projections 121d1 and 121d2 are displaced so as to spread out in the left-right direction (Y direction) due to the force exerted by the corners of the head 183a. At this time, the force exerted on the head 183a from the displaced arm 121d is greater than the force exerted on the head 183a from the arm 121d when the head 183a is in its initial position. Therefore, when the corners of the head 183a come into contact with the protrusions 121d1 and 121d2, the load on the head 183a during rotation becomes larger.

[0089] When the head 183a rotates further from the state in which the corners of the head 183a are in contact with the protrusions 121d1 and 121d2, and the head 183a rotates 15 degrees from its initial position, the corners of the head 183a engage with the recesses 121e of the respective protrusions 121d1 and 121d2. At this time, the protrusions 121d1 and 121d2, which have bent to spread out in the left-right direction, are displaced to return to their original state before deformation. Note that the displacement to return to the original state before deformation includes not only cases where the protrusions 121d1 and 121d2, which have bent to spread out in the left-right direction, completely return to their original state before deformation, but also cases where they are displaced to approach their original state.

[0090] When the corners of the head 183a engage with the recesses 121e of the respective protrusions 121d1 and 121d2, the force exerted from the arm 121d on the head 183a is smaller than the force exerted from the arm 121d on the head 183a when the protrusions 121d1 and 121d2 are displaced to spread outwards in the left-right direction (Y direction). Therefore, when the head 183a rotates 15 degrees from its initial position, the load on the head 183a during rotation is greater when the corners of the head 183a contact the respective protrusions 121d1 and 121d2, and then decreases when the head 183a moves to a position where its corners engage with the recesses 121e. In this way, when the head 183a rotates and changes state from a state where the corner of the head 183a abuts against the arm 121d to a state where the corner of the head 183a engages with the recess 121e, the magnitude of the force applied from the arm 121d to the head 183a changes. This change in the magnitude of the force changes the load applied to the head 183a during rotation, which can generate a clicking sensation in the head 183a.

[0091] Therefore, when the head 183a is rotated 15 degrees from its initial position, a clicking sensation is generated, and the head 183a is locked in place as the corners of the head 183a fit into the recesses 121d1 of the protrusion 121d1 and the recess 121d1 of the protrusion 121d2, respectively.

[0092] As the head 183a is further rotated and moves to a position 30 degrees rotated from its initial position, the protrusions 121d1 and 121d2 are displaced so as to spread out in the left-right direction, and then the corners of the head 183a engage with the recesses 121e provided on the inner surfaces of the respective protrusions 121d1 and 121d2.

[0093] Specifically, of the pair of protrusions 121d1 and 121d2, the corner of the head 183a is fitted into the second recess 121e located from the bottom of the left-hand protrusion 121d1. Also, the corner of the head 183a is fitted into the second recess 121e located from the top of the right-hand protrusion 121d2.

[0094] Therefore, when the head 183a is rotated 30 degrees from its initial position, a click sensation is generated, similar to when it is rotated 15 degrees from its initial position, and the corners of the head 183a are locked in place, fitted into the recesses 121d1 of the protrusion 121d1 and 121d2 of the protrusion 121d2, respectively.

[0095] Thus, the optical scanning device 100 can lock the head 183a in place by generating a click sensation every 15 degrees of rotation. Therefore, the user can easily grasp the amount of rotation of the second fθ lens 110, which rotates in conjunction with the amount of rotation of the head 183a. Furthermore, the optical scanning device 100 does not require any separate component to generate a click sensation in the head 183a.

[0096] Furthermore, by changing the number of recesses 121e provided on the inner surface of the arm portion 121d and the spacing between the recesses 121e, the amount of rotation (rotation angle) of the head portion 183a that generates a click sensation and locks the head portion 183a can be controlled.

[0097] Incidentally, in the arm portion 121d, the protrusions 121d1 and 121d2 are arranged in parallel so that the distance between them is equal. However, the protrusions 121d1 and 121d2 may be configured such that the widest distance is at least between their respective tips, as shown in Figure 11. Figure 11 is a diagram showing an example of the positional relationship between the head 183a of the adjustment member 183 and the arm portion 121d in the optical scanning device 100 according to a first modified embodiment of the present disclosure.

[0098] Thus, when the distance between the tip of the protrusion 121d1 and the tip of the protrusion 121d2 is configured to be the widest, the top cover 121 can be easily attached to the housing 120. That is, when attaching the top cover 121 to the housing 120, it is necessary to attach the top cover 121 so that the head portion 183a is sandwiched between the protrusions 121d1 and 121d2. Here, if the distance between the tip of the protrusion 121d1 and the tip of the protrusion 121d2 is wide, the head portion 183a can be easily sandwiched between the protrusions 121d1 and 121d2, and the top cover 121 can be attached to the housing 120.

[0099] Therefore, the assembly of the optical scanning device 100 can be made easier.

[0100] (Second variation) Next, the configuration of the optical scanning device 100 according to a second modified example of the embodiment of the present disclosure will be described with reference to Figure 12. Figure 12 is a diagram showing an example of the change in the positional relationship between the head 183a and the arm portion 121d of the adjustment member 183 provided in the optical scanning device 100 according to a second modified example of the embodiment of the present disclosure. Figure 12 shows the change in the positional relationship between the head 183a and the arm portion 121d each time the head 183a is rotated by 15 degrees.

[0101] Furthermore, the head 183a in the second modified embodiment of the present disclosure will be described using the case where the outer shape of the head 183a is a regular hexagon when viewed from above as an example. Also, for the sake of convenience of explanation, the case where the head 183a is rotated clockwise in a plan view will be described as an example.

[0102] The optical scanning device 100 according to the second modified embodiment of the present disclosure differs from the optical scanning device 100 according to the embodiment of the present disclosure in the following respects. Specifically, the optical scanning device 100 according to the embodiment of the present disclosure had an arm portion 121d having a pair of protrusions 121d1 and 121d2. In contrast, the optical scanning device 100 according to the second modified embodiment of the present disclosure differs in that the arm portion 121d is a single bendable member.

[0103] In other words, as shown in Figure 12, the arm portion 121d according to the second modified embodiment of the present disclosure protrudes from the upper cover side surface 121c toward the head portion 183a of the adjustment member 183, and is bent so that the folded portion 121d3 extends along the left-right direction (Y direction).

[0104] Here, when the head 183a is in its initial position, the top of the head 183a has a side surface that, in a plan view, extends in the left-right direction (Y direction) and forms an edge of the head 183a. The folded portion 121d3 is positioned to be in surface contact with the side surface of the top of the head 183a.

[0105] Furthermore, in the folded portion 121d3, a plurality of recesses 121e are provided continuously in the left-right direction (Y direction) on the contact surface that contacts the side of the head portion 183a.

[0106] The arm portion 121d has a fixed base end and a free tip, and the folded portion 121d3 is displaceable in the vertical direction (Z direction).

[0107] In other words, when the head 183a is rotated 15 degrees from its initial position, the corner of the head 183a comes into contact with the folded portion 121d3. The folded portion 121d3 is displaced upward by the force exerted by the corner of the head 183a. At this time, the force exerted on the head 183a from the displaced arm portion 121d is greater than the force exerted on the head 183a from the arm portion 121d when the head 183a is in its initial position. Therefore, when the corner of the head 183a comes into contact with the folded portion 121d3, the load on the head 183a during rotation becomes greater.

[0108] As the head 183a rotates further from the state in which it is in contact with the folded portion 121d3, and the head 183a rotates 15 degrees from its initial position, the corner of the head 183a engages with the recess 121e provided in the folded portion 121d3. In this case, as shown in Figure 12, the corner of the head 183a engages with the leftmost recess 121e provided in the folded portion 121d3. At this time, the folded portion 121d3, which has been displaced upward, is displaced to return to its original state before deformation. Note that the displacement to return to the original state before deformation includes not only the case where the folded portion 121d3, which has been displaced upward, completely returns to its original state before deformation, but also the case where it is displaced to approach its original state.

[0109] When the corner of the head 183a engages with the recess 121e of the folded portion 121d3, the force exerted from the arm portion 121d on the head 183a is smaller than the force exerted from the arm portion 121d on the head 183a when the folded portion 121d3 is displaced upward. Therefore, when the head 183a rotates 15 degrees from its initial position, the load on the head 183a during rotation is large when the corner of the head 183a contacts the folded portion 121d3, and then decreases when the head 183a moves to a position where its corner engages with the recess 121e. In this way, the magnitude of the force exerted from the arm portion 121d on the head 183a changes when the head 183a rotates and changes state from when its corner contacts the arm portion 121d to when its corner engages with the recess 121e. This change in the magnitude of the force alters the load applied to the head 183a during rotation, thereby generating a clicking sensation in the head 183a.

[0110] Therefore, when the head 183a is rotated 15 degrees from its initial position, a click sensation is generated, and the corner of the head 183a engages with the recess 121e, thereby locking the head 183a in place.

[0111] As the head portion 183a is further rotated and moves to a position 30 degrees rotated from the initial position, the folded portion 121d3 is displaced upward, and then the corner of the head portion 183a engages with the recess 121e provided on the contact surface of the folded portion 121d3.

[0112] In other words, the corner of the head portion 183a is fitted into the recess 121e, which is the second recess from the left in the folded portion 121d3.

[0113] Therefore, when the head 183a is rotated 30 degrees from its initial position, a click sensation is generated, similar to when it is rotated 15 degrees from its initial position, and the corner of the head 183a is locked in place with the recess 121e.

[0114] Thus, the optical scanning device 100 can lock the head 183a in place by generating a click sensation every 15 degrees of rotation. Therefore, the user can easily grasp the amount of rotation of the second fθ lens 110, which rotates in conjunction with the amount of rotation of the head 183a. Furthermore, the optical scanning device 100 does not require any separate component to generate a click sensation in the head 183a. [Explanation of Symbols]

[0115] 1. Image forming apparatus 100 Optical scanning device 110 Second fθ lens 120 cabinets 121 Top lid 121a Dustproof window 121b Top lid surface 121c Top lid side 121d Arm section 121d1 Projection 121d2 Projection 121d3 Folded section 121e recess 122 Bottom plate 123a side wall 123b side wall 123c side wall 123d side wall 180 Adjustment section 181 Retaining member 182 Slope 182a Slope 183 Adjustment Member 183a head 183b Screw part 186 Female screw component 188 Biasing member L Light Beam α Rotation axis

Claims

1. An fθ lens that focuses light onto the object to be irradiated, A housing section having an opening and housing the fθ lens, A cover portion that closes the opening of the housing portion and allows the light emitted from the fθ lens to pass through, The system includes an adjustment unit for adjusting the amount of rotation that rotates the fθ lens around a pivot axis extending along the thickness direction of the fθ lens, The adjustment unit is, The male screw member includes a head that protrudes outward from the side wall of the housing, and a screw portion that extends from the head along a first direction toward the fθ lens, passing through the side wall, and the tip of the screw portion moves along the first direction in response to the rotation of the head, thereby rotating the fθ lens. The optical scanning device has an arm portion that protrudes so as to abut against the outer circumference of the head portion and generates a clicking sensation in the head portion in accordance with the rotation of the head portion.

2. The side surface of the head has one or more protrusions, The optical scanning apparatus according to claim 1, wherein the cover portion generates the click sensation due to a change in the rotational load on the head, which occurs when the arm portion is deformed by the rotation of the head portion, with the convex portion contacting the arm portion, and then returns to its original state before deformation, resulting in a change in the force applied from the arm portion to the head portion.

3. The optical scanning device according to claim 2, wherein the outer shape of the head when viewed from above is a regular polygon, and the convex portion is a corner of the regular polygon.

4. The optical scanning apparatus according to claim 3, wherein the arm portion makes surface contact with a flat portion on the side surface of the head each time the head rotates by a predetermined angle, thereby locking the head in place.

5. The optical scanning apparatus according to claim 3, wherein the arm portion has a recess that engages with the protrusion of the head each time the head rotates by a predetermined angle, and the head is locked by engaging the recess of the arm portion with the protrusion of the head.

6. The optical scanning apparatus according to claim 4 or 5, wherein the arm portion has two protrusions that extend from the cover portion toward the head so as to sandwich the head.

7. The optical scanning apparatus according to claim 6, wherein the distance between the two protrusions of the arm portion is widest between the tips of the two protrusions.

8. The cover portion has an upper lid surface that closes the opening, and a side surface of the cover portion that is erected from the edge of the upper lid surface and extends along the side wall of the housing portion. The optical scanning device according to claim 1, wherein the arm portion extends along the side surface of the cover portion and protrudes from the side surface of the cover portion toward the head of the male screw member.

9. An image forming apparatus comprising the optical scanning device described in claim 1.

Images