JP5287777B2 - Optical scanning device - Google Patents

Description

  The present invention relates to an optical scanning device.

  In general, an image forming apparatus such as a laser printer is provided with an optical scanning device that exposes the surface of a photoreceptor. As such an optical scanning device, for example, as shown in Patent Document 1, a light source, a deflector (rotating polygonal mirror) that deflects and scans laser light, and laser light that has been deflected and scanned pass through a housing. Those equipped with a lens to be used are known.

JP 2007-328276 A

  By the way, in the conventional optical scanning device as described above, since laser light is emitted to the outside through a cover glass attached to an opening (slit) of the housing, it prevents dust from entering the housing. However, since all of the components such as the lens are housed in the housing, the apparatus has been enlarged.

  Therefore, in order to achieve downsizing of the apparatus, a configuration in which the housing is miniaturized by arranging a lens in the opening of the housing and exposing the exit surface of the lens to the outside without providing a cover glass is conceivable. . However, depending on the function of the lens, for example, the exit surface has a curved surface shape or the whole has a bow shape, so it is difficult to close the opening of the housing like a cover glass. There is a risk that the function of suppressing the intrusion of dust into the glass (hereinafter referred to as dustproof property) may be reduced.

  The present invention has been made in view of the background as described above, and an object thereof is to provide an optical scanning device capable of ensuring dust resistance while achieving downsizing.

In order to achieve the above object, an optical scanning device of the present invention includes a light source, a deflector that deflects and scans a light beam from the light source in a main scanning direction, and a light beam that is deflected and scanned by the deflector. An optical scanning device comprising a lens that passes through and a housing that supports the lens, wherein the lens includes an incident surface of the light beam, an exit surface of the light beam exposed to the outside of the housing, and A pair of side surfaces extending in the main scanning direction and connecting the incident surface and the exit surface, and the housing extends in the main scanning direction along the pair of side surfaces of the lens so as to partition the inside and outside of the housing a pair of dust-proof wall extending, possess a supporting surface for supporting the deflector, the lens is supported in a state where the optical axis is inclined relative to the support surface, the pair of dust-proof walls, the The support surface so as to sandwich the pair of side surfaces of the lens Inclined against the ends of the pair of dust-proof walls, characterized in that they do not overlap each other when viewed from the direction perpendicular to the support surface.

  According to the optical scanning device configured as described above, in a configuration in which the exit surface of the lens is exposed to the outside of the housing, the housing extends in the main scanning direction along the pair of side surfaces of the lens so as to partition the inside and outside of the housing. Since the pair of dustproof walls are provided, the gap between the housing and the lens can be reduced. Thereby, dustproofness can be ensured, achieving size reduction.

  According to the present invention, in the configuration in which the exit surface of the lens is exposed to the outside of the housing, the housing has a pair of dust-proof walls extending in the main scanning direction along the pair of side surfaces of the lens so as to partition the inside and outside of the housing. The dust-proof property can be ensured while downsizing.

1 is a diagram illustrating a schematic configuration of a laser printer including an optical scanning device according to an embodiment of the present invention. It is a top view which shows the structure of an optical scanning device. It is sectional drawing which shows the structure of an optical scanning device. It is a perspective view of a cylindrical lens. It is an expanded sectional view of an optical scanning device. It is the perspective view (a) which looked at the cylindrical lens vicinity from the inner side, and the perspective view (b) seen from the outer side. It is a top view of the optical scanning device which removed the cylindrical lens.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the following description, the schematic configuration of the image forming apparatus including the optical scanning device according to the embodiment of the present invention will be described first, and then the detailed configuration of the optical scanning device will be described.

<Schematic configuration of laser printer>
As shown in FIG. 1, a laser printer 1 (image forming apparatus) includes a paper feeding unit 3 for feeding paper S and an image forming unit 4 for forming an image on the paper S in a main body casing 2. Mainly prepared.

  Here, in the description of the schematic configuration of the laser printer 1, the direction will be described with reference to the user who uses the laser printer 1. That is, the right side in FIG. 1 is “front”, the left side is “rear”, the front side is “left”, and the back side is “right”. Also, the vertical direction in FIG.

  The paper feed unit 3 is provided at a lower portion in the main body casing 2 and mainly includes a paper feed tray 31, a paper pressing plate 32, and a paper feed mechanism 33. The paper S stored in the paper feed tray 31 is moved upward by the paper pressing plate 32 and supplied to the image forming unit 4 by the paper feed mechanism 33.

  The image forming unit 4 mainly includes an optical scanning device 100, a process cartridge 6, and a fixing device 7.

  The optical scanning device 100 is arranged at the upper part in the main casing 2 and is configured to emit a laser beam (see a chain line) based on image data and expose the surface of the photosensitive drum 61 to form an electrostatic latent image. Has been. A detailed configuration of the optical scanning device 100 will be described later.

  The process cartridge 6 is disposed below the optical scanning device 100 and is detachably mounted to the main casing 2 through an opening formed when a front cover (not shown) provided on the main casing 2 is opened. It has become. The process cartridge 6 includes a photosensitive drum 61, a charger 62, a transfer roller 63, a developing roller 64, a layer thickness regulating blade 65, a supply roller 66, and a toner storage unit that stores toner (developer). 67 mainly.

  In the process cartridge 6, the surface of the photosensitive drum 61 is uniformly charged by the charger 62 and then exposed by the laser beam from the optical scanning device 100, so that the photosensitive drum 61 is based on the image data. An electrostatic latent image is formed. Further, the toner in the toner container 67 is supplied to the developing roller 64 via the supply roller 66 and enters between the developing roller 64 and the layer thickness regulating blade 65 to form a thin layer having a constant thickness. Supported on.

  The toner carried on the developing roller 64 is supplied from the developing roller 64 to the electrostatic latent image formed on the photosensitive drum 61. As a result, the electrostatic latent image is visualized and a toner image is formed on the photosensitive drum 61. Thereafter, the sheet S is conveyed between the photosensitive drum 61 and the transfer roller 63, whereby the toner image on the photosensitive drum 61 is transferred onto the sheet S.

  The fixing device 7 is provided behind the process cartridge 6, and mainly includes a heating roller 71 and a pressure roller 72 that is disposed to face the heating roller 71 and presses the heating roller 71. In the fixing device 7, the toner image transferred onto the paper S is thermally fixed while the paper S passes between the heating roller 71 and the pressure roller 72. The sheet S on which the toner image has been heat-fixed is conveyed on the conveyance path 23 by the conveyance roller 73 and is discharged from the conveyance path 23 onto the paper discharge tray 22 by the discharge roller 24.

<Detailed configuration of optical scanning device>
Next, a detailed configuration of the optical scanning device 100 will be described. In the following description, the downstream side in the traveling direction of the laser light emitted from the light source device 120 is simply referred to as “downstream side”.

  As shown in FIGS. 2 and 3, the optical scanning device 100 includes a light source device 120, a cylindrical lens 127, a polygon mirror 130 as an example of a deflector, a polygon motor 140, and an fθ lens 150 in a housing 110. And a reflecting mirror 160 and a cylindrical lens 170 as an example of a lens.

  The light source device 120 includes a semiconductor laser light source 121 as an example of a light source that emits laser light (light beam), and a coupling lens 122 that condenses the laser light emitted from the semiconductor laser light source 121 and converts it into a parallel light beam. It is a well-known apparatus comprised including such as.

  The cylindrical lens 127 is a scanning lens that is disposed on the downstream side of the light source device 120 and through which the laser light emitted from the light source device 120 passes. The cylindrical lens 127 has a function of converting the laser light emitted from the light source device 120 so as to form an image on the polygon mirror 130 (reflection surface) only in the sub-scanning direction (direction orthogonal to the main scanning direction).

  The polygon mirror 130 is disposed on the downstream side of the cylindrical lens 127, and the six side surfaces of the hexagonal column are reflecting surfaces. The polygon mirror 130 reflects the laser light (laser light that has passed through the cylindrical lens 127) from the light source device 120 while rotating at high speed, and deflects it in the main scanning direction (substantially left-right direction in FIG. 2) and scans it at an equal angular velocity. . The polygon motor 140 is a known motor for rotationally driving the polygon mirror 130.

  The fθ lens 150 is a scanning lens that is disposed on the downstream side of the polygon mirror 130 and through which the laser light deflected and scanned by the polygon mirror 130 passes. The fθ lens 150 has a function of condensing the laser beam scanned at a constant angular velocity by the polygon mirror 130 onto the surface of the photosensitive drum 61 and converting it so as to scan at a constant velocity.

  The reflecting mirror 160 is disposed on the downstream side of the fθ lens 150, is deflected and scanned by the polygon mirror 130, reflects the laser light that has passed through the fθ lens 150, and turns back the optical path thereof, thereby converting the laser light into the cylindrical lens. It is aimed at 170.

  The cylindrical lens 170 is disposed on the downstream side of the reflecting mirror 160, is a scanning lens through which the laser light deflected and scanned by the polygon mirror 130, passes through the fθ lens 150, and is reflected by the reflecting mirror 160 passes. The cylindrical lens 170 has a function of correcting surface tilt of the polygon mirror 130 by refracting the laser light and converging it in the sub-scanning direction. In addition, the cylindrical lens 170 has a function of correcting the surface tilt of the laser beam that is paired with the cylindrical lens 127 and converted into a light beam.

  As shown in FIG. 4, the cylindrical lens 170 connects a pair of lens surfaces that are long in the main scanning direction, specifically, an incident surface 171 and an exit surface 172 of laser light, and an entrance surface 171 and an exit surface 172. It has a pair of side surfaces 173 and 174 extending in the scanning direction. The entrance surface 171 and the exit surface 172 have a bow shape when viewed from the sub-scanning direction (see FIG. 2). As shown in FIG. 5, such a cylindrical lens 170 is supported by the casing 110 (base frame 200) with the emission surface 172 exposed to the outside of the casing 110.

  In the following description, for convenience of explanation, of the pair of side surfaces 173 and 174, a surface facing the inside of the housing 110 in a state where the cylindrical lens 170 is supported by the housing 110 is referred to as an inner side surface 173. A surface opposite to the side surface 173 is referred to as an outer surface 174.

  2 and 3, in the optical scanning device 100, laser light (see the chain line) based on the image data emitted from the light source device 120 is converted into a cylindrical lens 127, a polygon mirror 130, an fθ lens 150, a reflecting mirror 160, and a cylindrical lens. The light is reflected or passed in the order of 170 and is scanned at high speed on the surface (scanned surface) of the photosensitive drum 61 (see FIG. 1). As a result, the surface of the photosensitive drum 61 is exposed, and an electrostatic latent image based on the image data is formed on the photosensitive drum 61.

  The housing 110 is a box-shaped member that supports the light source device 120, the polygon motor 140, the cylindrical lens 170, and the like. More specifically, as shown in FIG. 3, the casing 110 covers a box-shaped (container-shaped) base frame 200 whose upper portion (upper portion in FIG. 3) is open, and an open portion of the base frame 200. And a lid frame 300 attached to the frame.

  The base frame 200 has a support surface 212 that supports the polygon mirror 130 and a pair of dust-proof walls 223 and 224 provided along the cylindrical lens 170 on the bottom wall portion 210 of the box (vessel). .

  A mounting plate 141 of the polygon motor 140 is fixed to the support surface 212 by a plurality of screws N. With such a configuration, the polygon mirror 130 is supported on the support surface 212 via the polygon motor 140.

  As shown in FIGS. 5 and 6, the pair of dustproof walls 223 and 224 are integrally formed as a part of the base frame 200 so as to partition the inside and outside of the housing 110 (inside and outside of the bottom wall portion 210). The cylindrical lens 170 is provided so as to extend along the inner side surface 173 or the outer side surface 174 in the main scanning direction (longitudinal direction).

  More specifically, as shown in FIG. 6A, the dust-proof wall 223 extends in the main scanning direction along the inner surface 173 so as to close a gap between the bottom wall portion 210 and the inner surface 173 of the cylindrical lens 170. It extends. More specifically, in the dust-proof wall 223, the end 223A has a curved shape along the bow shape of the emission surface 172.

  Further, as shown in FIG. 6B, the dust-proof wall 224 extends in the main scanning direction along the outer surface 174 so as to close the gap between the bottom wall portion 210 and the outer surface 174 of the cylindrical lens 170. Yes. More specifically, the dust-proof wall 224 has a curved shape in which the end 224 </ b> A follows the arc shape of the incident surface 171.

  As shown in FIG. 5, in this embodiment, the cylindrical lens 170 has its optical axis (see the alternate long and short dash line) inclined with respect to the support surface 212 (the extended surface 212 ′ of the support surface 212 (see the alternate long and two short dashes line)). In this state, it is supported by the base frame 200 (housing 110). Correspondingly, the pair of dustproof walls 223 and 224 are inclined with respect to the support surface 212 (extension surface 212 ′) so as to sandwich the inner surface 173 and the outer surface 174 of the cylindrical lens 170.

  A gap is formed between the cylindrical lens 170 and the dustproof walls 223 and 224. More specifically, a gap D3 smaller than the thickness T3 of the dust-proof wall 223 is formed between the cylindrical lens 170 and the dust-proof wall 223. Further, a gap D4 smaller than the thickness T4 of the dust-proof wall 224 (T3 = T4 in the present embodiment) is formed between the cylindrical lens 170 and the dust-proof wall 224.

  Accordingly, it is possible to suppress contact between the cylindrical lens 170 and the dust-proof walls 223 and 224 when the housing 110 (base frame 200) resonates due to vibration or the like when the polygon motor 140 is rotationally driven. As a result, since it is difficult for external force to be applied to the cylindrical lens 170, deformation and displacement of the cylindrical lens 170 can be suppressed.

  As shown in FIGS. 5 and 7, the pair of dust-proof walls 223 and 224 are viewed from a direction (upward direction in FIG. 5) where the end portions 223A and 224A are orthogonal to the support surface 212 (extension surface 212 ′). It is formed so as not to overlap each other. According to this, since it is possible to pull out the mold constituted by two parts in the vertical direction of FIG. 5, the base frame 200 (housing 110) integrally having the dustproof walls 223 and 224 is formed by injection molding or the like. It becomes possible to mold easily.

According to the above, the following effects can be obtained in the present embodiment.
Since a part of the cylindrical lens 170 (outgoing surface 172) is exposed to the outside of the housing 110, the housing has a cover glass and all the lenses are accommodated in the housing 110. 110 can be reduced in size. Thereby, the optical scanning device 100 can be reduced in size.

  Since the housing 110 has a pair of dustproof walls 223 and 224 extending in the main scanning direction along the inner surface 173 or the outer surface 174 of the cylindrical lens 170 so as to partition the inside and the outside of the housing 110, the housing 110 and the cylindrical lens 170 The gap between them can be reduced. Thereby, the dustproof property of the optical scanning device 100 can be ensured.

  As described above, according to the optical scanning device 100 of the present embodiment, it is possible to ensure dustproofness while reducing the size of the device.

  Since the cylindrical lens 170 is supported in a state where the optical axis is inclined with respect to the support surface 212, compared to a configuration in which the optical axis of the cylindrical lens 170 is supported in a state orthogonal to the support surface 212, The degree of freedom of arrangement of the optical scanning device 100 can be increased. Accordingly, it is possible to reduce the size of the laser printer 1 to which the optical scanning device 100 is applied.

  In the configuration in which the optical axis of the cylindrical lens 170 is supported in an inclined state, a large gap is easily formed between the housing 110 and the cylindrical lens 170. However, in the present embodiment, the pair of dustproof walls 223 and 224 are inclined with respect to the support surface 212 so as to sandwich the inner surface 173 and the outer surface 174 of the cylindrical lens 170, so that a large gap is easily formed. However, it is possible to ensure the dust resistance more reliably.

  Since the pair of dust-proof walls 223 and 224 are integrally formed, the dust-proof walls 223 and 224 can be accurately molded, and the dust-proof property can be improved.

  Since the incident surface 171 and the exit surface 172 of the cylindrical lens 170 have a bow shape, and the end portions 223A and 224A of the dust-proof walls 223 and 224 are curved along the bow shape of the entrance surface 171 or the exit surface 172. A gap between the body 110 and the cylindrical lens 170 can be further reduced. Thereby, dustproofness can be ensured more reliably.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. About a concrete structure, it can change suitably in the range which does not deviate from the meaning of this invention.

  In the above embodiment, the configuration in which both the incident surface 171 and the exit surface 172 of the cylindrical lens 170 (lens) have a bow shape is illustrated, but the present invention is not limited thereto. Only one of them may have a bow shape.

  In the above-described embodiment, the configuration in which the gaps D3 and D4 are formed between the cylindrical lens 170 (lens) and the dust-proof walls 223 and 224 is exemplified. However, the present invention is not limited to this, and for example, between the lens and the dust-proof wall. A seal member or the like may be provided. According to this, dustproofness can be improved more. In addition, although the case where the thickness of a pair of dust-proof walls was mutually equal (T3 = T4) was illustrated in previous embodiment, the thickness of a pair of dust-proof walls may mutually differ.

  In the above-described embodiment, the configuration in which the pair of dust-proof walls 223 and 224 are integrally formed is illustrated. However, the present invention is not limited to this. For example, the pair of dust-proof walls are individually molded and attached to the housing in the assembly process. It is good also as a structure. In such a configuration, the ends of the pair of dustproof walls may overlap each other when viewed from the direction orthogonal to the support surface.

  In the embodiment, the cylindrical lens 170 (lens) is supported in a state where the optical axis is inclined with respect to the support surface 212, and the pair of dust-proof walls 223 and 224 sandwich the inner surface 173 and the outer surface 174 so as to sandwich the support surface 212. However, the present invention is not limited to this. For example, the lens may be supported in a state where the optical axis is orthogonal to the support surface, and the pair of dustproof walls may be orthogonal to the support surface so as to sandwich the pair of side surfaces of the lens.

In the embodiment, the semiconductor laser light source 121 is exemplified as the light source. However, the present invention is not limited to this. For example, a solid laser light source such as a YAG laser may be adopted.
Moreover, in the said embodiment, although the structure which emitted the laser beam (light beam) converted into the parallel light beam from the light source device 120 was illustrated, it is not limited to this, For example, convergent light and a divergent light beam are radiate | emitted. It is good also as a structure to be.

  In the embodiment, the polygon mirror 130 that deflects and scans the laser light (light beam) by rotating the reflection surface is exemplified as the deflector. However, the present invention is not limited to this, and for example, the reflection surface oscillates. A vibrating mirror that deflects and scans the light beam may be employed.

  In the embodiment, the cylindrical lens 170 is exemplified as the lens, but the lens is not limited thereto. That is, the lens of the present invention is not particularly limited as long as it is a lens arranged so that the light beam exit surface is exposed to the outside of the housing.

  Note that the cylindrical lens 170 of the above embodiment has a function of correcting the surface tilt of the polygon mirror 130, so that the passage area of the laser light passing through the emission surface 172 is large. For this reason, even if some dust adheres to the exit surface 172, it is difficult to affect the image characteristics, so that it can be suitably used as a lens that exposes the exit surface to the outside of the housing.

  In the above-described embodiment, the laser printer 1 is exemplified as the image forming apparatus. However, the image forming apparatus is not limited thereto, and may be a copying machine, a multifunction machine, or the like. In the above embodiment, the optical scanning device of the present invention is applied to the image forming apparatus (laser printer 1). However, the present invention is not limited to this. For example, the optical scanning device may be applied to a measuring device or an inspection device. Good.

DESCRIPTION OF SYMBOLS 100 Optical scanning device 110 Case 120 Light source device 121 Semiconductor laser light source 130 Polygon mirror 170 Cylindrical lens 171 Incident surface 172 Output surface 173 Inner side surface 174 Outer side surface 200 Base frame 210 Bottom wall portion 212 Support surface 223 Dustproof wall 223A End portion 224 Dustproof Wall 224A End D3 Gap D4 Gap T3 Thickness T4 Thickness

Claims (6)

A light source; a deflector that deflects and scans a light beam from the light source in a main scanning direction; a lens through which the light beam deflected and scanned by the deflector passes; and a housing that supports the lens. An optical scanning device,
The lens has a light beam entrance surface, a light beam exit surface exposed outside the housing, and a pair of side surfaces that connect the entrance surface and the exit surface and extend in the main scanning direction,
Wherein the housing, possess a pair of dust-proof wall extending in the main scanning direction along the pair of side surfaces of the lens so as to partition the inside and outside of the housing and a supporting surface for supporting the deflector,
The lens is supported in a state where an optical axis is inclined with respect to the support surface,
The pair of dust barrier walls are inclined with respect to the support surface so as to sandwich the pair of side surfaces of the lens,
An end portion of the pair of dustproof walls does not overlap each other when viewed from a direction orthogonal to the support surface . A reflecting mirror that directly reflects the laser light deflected and scanned by the deflector and turns the optical path thereof toward the lens;
2. The light according to claim 1, wherein an angle formed between an optical axis of the laser light incident on the reflecting mirror and an optical axis of the laser light reflected toward the lens by the reflecting mirror is an acute angle. Scanning device. The pair of dust-proof walls, the optical scanning apparatus according to claim 1 or claim 2, characterized in that it is integrally molded. Between the lens and the dust-proof walls, the optical scanning apparatus according to any one of claims 1 to 3, characterized in that small gap than the thickness of the dust-proof wall is formed. It said lens includes an optical scanning apparatus according to any one of claims 1 to 4, characterized in that it has a function to correct tilt of the deflector. In the lens, at least one of the entrance surface and the exit surface has a bow shape,
The end of the dust-proof walls, the optical scanning apparatus according to any one of claims 1 to 5, characterized in that a curved shape along the arch shape of the incident surface or the exit surface .

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