JP2015206910A - Optical scanning device and image formation device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical scanning device in which rigidity of a housing can be prevented from lowering.SOLUTION: An optical scanning device 19 includes: a polygon mirror 34 that performs polarization scanning of beam light; a scanning optical system 35 that forms an image of the beam light onto a scanned surface; a folding mirror 36 that folds the beam light and guides it to an image carrier; and a housing 31. The housing 31 includes: a first area 31a where a the polygon mirror 34 is placed on one surface side; a second area 31b where the folding mirror 36 is placed on the other surface side; and a step wall portion 31c that connects the first area 31a and the second area 31b in a step shape. In the step wall portion 31c, a first opening portion 31f for causing the beam light from the polygon mirror 34 to pass through and reach the folding mirror 36 is provided.

Description

  The present invention relates to an optical scanning apparatus that forms a latent image on a surface to be scanned by exposure scanning, and an image forming apparatus such as a copying machine, a printer, a facsimile, and a multi-function machine including the optical scanning apparatus.

  In general, an optical scanning device used for a copying machine, a printer, or the like is a light source, a polygon mirror (rotating polygonal mirror) that deflects and scans the beam light from the light source, and a surface to be scanned with the beam light deflected by the polygon mirror. An fθ lens that forms an image above, a folding mirror that folds the beam light that has passed through the fθ lens and guides it to the image carrier, and a housing to which these are fixed.

  This optical scanning device is very sensitive to dust such as dust and dust. If dust adheres to the fθ lens, the folding mirror, especially the polygon mirror, the beam light is blocked by the dust and the amount of light is reduced. In addition, image defects such as streaks and uneven density are caused. For this reason, a housing space for housing the polygon mirror, the fθ lens, and the folding mirror is formed by the housing, the cover member, and the like.

  The housing includes a bottom surface portion to which the polygon mirror, the fθ lens, and the folding mirror are fixed, and a side wall portion that stands from the edge of the bottom surface portion. The beam light emitted from the light source passes through the polygon mirror and the fθ lens, is then folded back by the folding mirror, and is irradiated toward the photosensitive drum through the opening formed in the bottom surface of the housing.

  An optical scanning device in which an opening for allowing the beam light reflected by the folding mirror to pass through is formed on the bottom surface of the casing to which the polygon mirror, the fθ lens, and the folding mirror are fixed is disclosed in, for example, Patent Document 1. ing.

JP-A-11-24531

  By the way, the beam light deflected and scanned by the polygon mirror spreads in the main scanning direction as the distance from the polygon mirror increases. In the conventional optical scanning device, since the opening is provided after the downstream mirror (downstream side), it is necessary to form the opening widely. For this reason, since the rigidity of the housing is lowered, there is a problem in that an image defect is likely to occur due to vibration during printing.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an optical scanning device capable of suppressing a decrease in the rigidity of a housing and an image including the same. A forming apparatus is provided.

  In order to achieve the above object, an optical scanning device of the present invention includes a rotary polygon mirror that deflects and scans light beams from a light source unit, and a lens that forms an image of the beam light deflected by the rotary polygon mirror on a surface to be scanned. And a folding mirror that folds the beam light that has passed through the lens and guides it to the image carrier, and a rotating polygon mirror, and a casing to which the lens and the folding mirror are fixed. A first region disposed on the second surface, a second region on which the folding mirror is disposed on the other surface side, and a stepped wall portion that connects the first region and the second region in a stepped shape. A first cover member that covers the rotating polygon mirror is provided on one surface side of the lens, and a storage space for storing the rotating polygon mirror is formed by the first region of the casing, the step wall portion, and the first cover member. The light beam from the rotating polygonal mirror is First opening for passed through to reach the folding mirror is formed.

  According to the present invention, the housing includes a first wall area where the rotating polygon mirror is disposed, a second area where the folding mirror is disposed, and a step wall portion connecting the first area and the second area in a step shape. And a first opening for allowing the beam light from the rotating polygon mirror to pass through and reaching the folding mirror is formed in the stepped wall. In this way, the first opening is formed in the stepped wall portion disposed between the rotating polygon mirror and the folding mirror, so that the first opening is formed in the housing portion at the rear (downstream side) of the folding mirror. Compared to the case of forming, the first opening can be formed smaller. For this reason, since it can suppress that the rigidity of a housing | casing falls, generation | occurrence | production of the image defect by the vibration etc. at the time of printing can be suppressed.

  Moreover, since a 1st opening part can be made small, it can suppress that a dust penetrate | invades into storage space from a 1st opening part. Thereby, since it can suppress that dust adheres to a polygon mirror, generation | occurrence | production of an image defect can be suppressed more.

1 is a cross-sectional view schematically showing a structure of an image forming apparatus including an optical scanning device according to an embodiment of the present invention. It is the perspective view which showed the structure of the optical scanning device of one Embodiment of this invention from the upper side. It is the bottom view which showed the structure of the optical scanning device of one Embodiment of this invention. It is sectional drawing which showed the structure of the optical scanning device of one Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  The image forming apparatus 1 including the optical scanning device 19 according to an embodiment of the present invention will be described with reference to FIGS.

  A paper feed cassette 2 that accommodates stacked paper is disposed below the apparatus main body 1a of the image forming apparatus 1 of the present embodiment. In FIG. 1, the right side is illustrated as the front side of the image forming apparatus 1. Above this paper feed cassette 2, there is formed a paper conveyance path 4 that extends substantially horizontally from the front to the rear of the apparatus main body 1a and further extends upward to reach the paper discharge unit 3 formed on the upper surface of the apparatus main body 1a. ing. A pickup roller 5, a feed roller 6, an intermediate transport roller 7, a registration roller pair 8, an image forming unit 9, a fixing unit 10, and a discharge roller pair 11 are arranged in this order along the paper transport path 4 from the upstream side.

  The paper feed cassette 2 is provided with a paper stacking plate 12 that is rotatably supported with respect to the paper feed cassette 2. When the paper stacked on the paper stacking plate 12 is sent out toward the paper transport path 4 by the pickup roller 5, and when a plurality of papers are sent out simultaneously by the pickup roller 5, the feed roller 6, the retard roller 13, Thus, the sheet is rolled up and only the topmost sheet is conveyed. The sheet sent to the sheet conveyance path 4 is conveyed to the registration roller pair 8 by changing the conveyance direction to the rear of the apparatus main body 1a by the intermediate conveyance roller 7, and the timing is adjusted by the registration roller pair 8 to form an image. Supplied to section 9.

  The image forming unit 9 forms a predetermined toner image on a sheet by an electrophotographic process. The photosensitive member 14 is an image carrier that is pivotally supported in a clockwise direction in FIG. The charging device 15, the developing device 16, the cleaning device 17, the transfer roller 18 disposed so as to face the photoconductor 14 across the paper conveyance path 4, and the light disposed above the photoconductor 14. A toner container 20 that is composed of a scanning device 19 and supplies toner to the developing device 16 is disposed above the developing device 16.

  The charging device 15 is provided with a conductive rubber roller 15 a connected to a power source (not shown), and the conductive rubber roller 15 a is disposed so as to contact the photoreceptor 14. When the photosensitive member 14 rotates, the conductive rubber roller 15a comes into contact with the surface of the photosensitive member 14 and is driven to rotate. At this time, by applying a predetermined voltage to the conductive rubber roller 15a, The surface is charged uniformly.

  Next, an electrostatic latent image based on the image data input on the photoconductor 14 is formed by the beam light emitted from the optical scanning device 19, and toner is attached to the electrostatic latent image by the developing device 16, so that the photoconductor 14 is formed. A toner image is formed on the surface. Then, the paper is supplied from the registration roller pair 8 to the nip portion (transfer position) between the photoconductor 14 and the transfer roller 18 at a predetermined timing, and the toner image on the surface of the photoconductor 14 is transferred onto the paper by the transfer roller 18. The

  The sheet onto which the toner image has been transferred is separated from the photoreceptor 14 and conveyed toward the fixing unit 10. The fixing unit 10 is disposed on the downstream side of the image forming unit 9 in the paper conveyance direction, and the sheet on which the toner image is transferred in the image forming unit 9 includes a heating roller 21 provided in the fixing unit 10 and the heating roller 21. The toner image that is heated and pressed by the pressure roller 22 pressed against the heating roller 21 and transferred to the paper is fixed.

  The paper on which the image is formed is discharged to the paper discharge unit 3 by the discharge roller pair 11. On the other hand, the toner remaining on the surface of the photoconductor 14 after the transfer is removed by the cleaning device 17, the photoconductor 14 is charged again by the charging device 15, and image formation is performed in the same manner.

  Next, the optical scanning device 19 will be described. 2 and 3, the optical scanning device 19 includes a light source unit 33, a polygon mirror 34 that is a rotating polygon mirror, a scanning optical system (lens) 35, a folding mirror 36, a detection sensor 38, And a housing 31 to which these are fixed.

  The light source unit 33 includes a light source such as a laser diode that outputs laser light and a cylindrical lens or a collimating lens that shapes the beam diameter of the laser light, and is modulated based on image data input from a personal computer (not shown). Emits the light beam.

  The polygon mirror 34 is rotated at a predetermined speed by the polygon motor 39 and deflects the beam light emitted from the light source unit 33 so as to scan in the main scanning direction M. The polygon motor 39 is driven and controlled by the circuit board 40.

  The scanning optical system 35 is composed of one or more lenses, refracts the beam light reflected by the polygon mirror 34 so as to be scanned at a constant speed in the main scanning direction M, and condenses the beam light on the surface to be scanned. Let me image. In the present embodiment, the scanning optical system 35 is configured by one fθ lens. As shown in FIG. 4, the folding mirror 36 reflects the beam light emitted from the scanning optical system 35 so as to be folded toward the lower side of the scanning optical system 35 and guides it to the photosensitive member 14 (see FIG. 1).

  As shown in FIG. 3, the detection sensor 38 outputs a signal for controlling the exposure range in the main scanning direction M, and passes through the scanning optical system 35 via a detection mirror 37 disposed outside the exposure range. Receive the light beam.

  In the above configuration, as shown in FIGS. 2 to 4, the light source unit 33 emits the light beam modulated based on the image data toward the polygon mirror 34. The polygon mirror 34 reflects the beam light emitted from the light source unit 33 and deflects and scans the reflected light by its rotation. The scanning optical system 35 converts the beam light reflected by the polygon mirror 34 into constant speed scanning, and forms an image on the surface of the photosensitive member 14 (see FIG. 1), which is a scanned surface, via the folding mirror 36. As a result, the optical scanning device 19 exposes and scans a predetermined range in the main scanning direction M on the photoconductor 14, and an electrostatic latent image is formed on the photoconductor 14.

  The casing 31 to which the polygon mirror 34 and the folding mirror 36 are fixed is formed of a resin having a good thermal conductivity, and the light source unit 33 and the polygon mirror 34 are arranged in a substantially flat plate shape on the upper surface side (one surface side). The first region 31a, the substantially flat plate-like second region 31b where the folding mirror 36 is disposed on the lower surface side (the other surface side), and the step wall that connects the first region 31a and the second region 31b in a step shape. Part 31c.

  A concave portion 31d in which the polygon mirror 34 is disposed is provided in the central portion of the first region 31a, and a side wall portion 31e that is erected upward is provided at the edge portion. Further, a first cover member 41 (see FIG. 4) covering the upper side of the polygon mirror 34 is attached to the upper surface side (one surface side) of the first region 31a, and the first region 31a, the step wall portion 31c, and A storage space S1 for storing the light source unit 33, the polygon mirror 34, and the like is formed by the first cover member 41 and the like. 2 and 3, the first cover member 41 and the second cover member 42 described later are omitted.

  The polygon mirror 34 is integrally attached to the rotation shaft of the polygon motor 39, and the polygon motor 39 is fixed to the first region 31a with the circuit board 40 interposed therebetween. The circuit board 40 is mounted with a driver IC or the like that controls the rotational drive of the polygon motor 39, and is fixed to the recess 31d of the first region 31a.

  The step wall 31 c of the housing 31 is formed with a first opening 31 f for allowing the beam light deflected by the polygon mirror 34 to pass through the scanning optical system 35 and reach the folding mirror 36.

  The scanning optical system 35 is disposed in the vicinity of the first opening 31f. In the present embodiment, the scanning optical system 35 is disposed on the folding mirror 36 side of the first opening 31f. That is, the first opening 31 f is disposed between the polygon mirror 34 and the scanning optical system 35. 2 and 4, a part of the scanning optical system 35 may be disposed in the first opening 31f. The first opening 31f includes an opening extending in the main scanning direction M, and is formed to have a length of about 1/3 to 1/2 of a second opening 42a described later.

  A side wall 31g is provided at the edge of the lower surface side (the other surface side) of the second region 31b of the housing 31 so as to stand downward. A second cover member 42 that covers the lower side of the folding mirror 36 is attached to the lower surface side of the second region 31b, and the folding mirror is formed by the second region 31b, the step wall portion 31c, the second cover member 42, and the like. 36, a storage space S2 for storing the detection mirror 37, the detection sensor 38, and the like is formed.

  As shown in FIG. 4, the folding mirror 36 is inclined by a predetermined angle with respect to the second region 31b in order to reflect the light beam emitted from the scanning optical system 35 toward the photosensitive member 14 (see FIG. 1). Fixed.

  The second cover member 42 is formed with a second opening 42 a for allowing the beam light from the folding mirror 36 to pass through and reaching the photoreceptor 14. The second opening 42a is formed behind the folding mirror 36 (on the downstream side) and has an opening that extends in the main scanning direction M and has substantially the same length as the horizontally folding mirror 36.

  In addition, a light transmission member 43 made of a transparent glass plate or the like is fixed to the second cover member 42 so as to close the second opening 42a. Thereby, it can suppress that dust penetrate | invades in storage space S2.

  In the present embodiment, as described above, the first opening 31f is formed in the step wall portion 31c disposed between the polygon mirror 34 and the folding mirror 36, so that the rear (downstream side) of the folding mirror 36 is provided. Compared to the case where the first opening 31 f is formed in the portion of the housing 31, the first opening 31 f can be formed smaller. For this reason, since it can suppress that the rigidity of the housing | casing 31 falls, generation | occurrence | production of the image defect by the vibration etc. at the time of printing can be suppressed.

  Moreover, since the 1st opening part 31f can be made small, it can suppress that a dust penetrate | invades into storage space S1 from the 1st opening part 31f. Thereby, since it can suppress that dust adheres to a polygon mirror, generation | occurrence | production of an image defect can be suppressed more.

  As described above, the first opening 31 f is disposed between the polygon mirror 34 and the scanning optical system 35. As a result, the first opening 31f can be made closer to the polygon mirror 34, so that the first opening 31f can be formed smaller.

  As described above, the scanning optical system 35 is disposed in the vicinity of the first opening 31f. Thereby, it can suppress more that dust penetrate | invades into storage space S1 from the 1st opening part 31f.

  Further, as described above, by providing the second cover member 42 that covers the folding mirror 36 in the second region 31b of the housing 31, it is possible to suppress dust from adhering to the scanning optical system 35 and the folding mirror 36. Therefore, the occurrence of image defects can be further suppressed.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, although an example in which the present invention is applied to a monochrome printer as shown in FIG. 1 has been shown, the present invention is not limited to this. Needless to say, the present invention is applied to various image forming apparatuses including an optical scanning device that forms a latent image on a surface to be scanned by exposure scanning, such as a color printer, a color copying machine, a monochrome copying machine, a digital multifunction machine, and a facsimile machine. Applicable.

  In the above embodiment, the first opening 31f is arranged between the polygon mirror 34 and the scanning optical system 35. However, the first opening 31f is arranged with the scanning optical system 35 and the folding mirror 36. You may arrange | position between.

  In the above embodiment, the second cover member 42 that covers the folding mirror 36 is provided in the second region 31b. However, the second cover member 42 may not be provided. However, when the second cover member 42 is not provided, dust is likely to adhere to the scanning optical system 35 and the folding mirror 36, so it is desirable to provide the second cover member 42.

  Moreover, although the scanning optical system 35 was arrange | positioned in the vicinity of the 1st opening part 31f in the said embodiment, and it showed about the example which suppressed dust invading into storage space S1 from the 1st opening part 31f, it showed the 1st The scanning optical system 35 may be arranged so as to seal the one opening 31f. If comprised in this way, it can further suppress that dust penetrate | invades into storage space S1 from the 1st opening part 31f.

DESCRIPTION OF SYMBOLS 1 Image forming device 19 Optical scanning device 31 Case 31a 1st area | region 31b 2nd area | region 31c Step wall part 31f 1st opening part 33 Light source part 34 Polygon mirror (rotating polygon mirror)
35 Scanning optical system (lens, fθ lens)
36 Folding mirror 41 First cover member 42 Second cover member 42a Second opening S1 Storage space

Claims (7)

A rotating polygon mirror that deflects and scans the light beam from the light source unit;
A lens for imaging the beam light deflected by the rotary polygon mirror on the surface to be scanned;
A folding mirror for folding the beam light that has passed through the lens and guiding it to the image carrier;
A casing to which the rotary polygon mirror, the lens and the folding mirror are fixed;
With
The casing has a step between a first area where the rotary polygon mirror is arranged on one side, a second area where the folding mirror is arranged on the other side, and the first area and the second area. A stepped wall portion connected in a shape,
A first cover member that covers the rotary polygon mirror is provided on the one surface side of the first region,
A storage space for storing the rotary polygon mirror is formed by the first region of the casing, the stepped wall portion, and the first cover member.
The optical scanning device according to claim 1, wherein the stepped wall portion is formed with a first opening for allowing the beam light from the rotary polygon mirror to pass through and reaching the folding mirror.   The optical scanning device according to claim 1, wherein the first opening is disposed between the rotary polygon mirror and the lens.   The optical scanning device according to claim 1, wherein the lens is disposed in the vicinity of the first opening.   The optical scanning device according to claim 3, wherein the lens is disposed so as to seal the first opening. A second cover member that covers the folding mirror is provided on the other surface side of the second region,
The second cover member is formed with a second opening for allowing the beam light from the folding mirror to pass through and reaching the surface to be scanned. The optical scanning device according to Item.   The optical scanning device according to claim 1, wherein the lens is an fθ lens for imaging the beam light on a surface to be scanned at a constant speed.   An image forming apparatus comprising the optical scanning device according to claim 1.

Images