JP6525258B2 - Optical scanning device and image forming apparatus - Google Patents

Description

  The present invention relates to an optical scanning device and an image forming apparatus.

  Image forming apparatuses such as printers, copiers, and facsimiles are provided with an optical scanning device that deflects a light beam emitted from a light source with a deflector and optically scans it, and irradiates a photosensitive member to write a latent image. . Patent Document 1 includes a light shielding member for shielding so-called flare light, which is light traveling to a path different from a predetermined path, out of light emitted from an fθ lens that constitutes a part of an optical system through which light rays pass. An optical scanning device is described.

In the optical scanning device described in Patent Document 1, the light shielding member is fixed with a fixing structure at both ends to a holder that holds an optical system component such as an fθ lens. In the case of the both-end fixed structure, when the distance between the fixed locations in the light shielding member and the distance between the fixed locations in the holder are different due to the difference in expansion amount at the time of thermal expansion, the light shielding member and the holder Stress or compressive stress acts on the
When stress is applied to the holder to cause deformation, the optical system held by the holder is displaced, and the irradiation position of the light beam with respect to the photosensitive member may be deviated, which may cause positional deviation of the image.

In order to solve the problems described above, according to the first aspect of the present invention, an optical system constituent member constituting a part of an optical system through which a light beam passes, a holder for holding the optical system, and the optical system constituent member In an optical scanning device having a light shielding member that shields light traveling to a path different from a predetermined path among emitted light, only one end of the light shielding member is fixed to the holding body, and The fixing position to the holding body is above the upper surface of the optical system component, and a part of the light shielding member faces the upper surface of the optical system component .

  According to the present invention, there is an excellent effect that stress can be prevented from acting on the holder due to the provision of the light shielding member in the optical scanning device.

FIG. 8 is an enlarged explanatory view of the vicinity of the scanning lens and the dustproof glass of the writing unit. FIG. The schematic block diagram of a write unit. FIG. 5 is an enlarged perspective view of the vicinity of a polygon scanner of the writing unit. The perspective view which shows the optical path which the reflected light in a soundproof glass injects into a scanning lens as flare light. FIG. 5 is a side cross-sectional view of the scanning lens showing an optical path until flare light enters and exits the scanning lens. FIG. 7 is an enlarged cross-sectional view of the writing unit showing a state in which flare light emitted from the upper surface of the scanning lens passes through the dustproof glass. FIG. 7 is an enlarged perspective view of the vicinity of the mounting position of the light shielding member before the light shielding member is mounted in the writing unit. FIG. 7 is an enlarged perspective view of the vicinity of the light shielding member in a state where the light shielding member is attached in the writing unit.

  An embodiment of an electrophotographic image forming apparatus including a writing unit which is an optical scanning device to which the present invention is applied will be described below.

FIG. 2 is a schematic block diagram of a multifunction peripheral 500 which is an image forming apparatus according to the present embodiment.
The MFP 500 includes an image forming unit 200, a sheet feeding unit 400 disposed below the image forming unit 200, and a reading unit 300 disposed above the image forming unit 200.

The image forming unit 200 includes four image forming devices 1 (Y, M, C, K) corresponding to the respective colors of yellow (Y), magenta (M), cyan (C), and black (K). Y, M, C, and K added after the numerals of the respective symbols indicate that they are members for yellow, magenta, cyan, and black (the same applies hereinafter). The four image forming apparatuses 1 (Y, M, C, K) have substantially the same configuration except that the colors of the toners to be handled are different from one another. The suffixes “M”, “C”, and “K” are appropriately omitted.
The image forming apparatus 1 includes a photosensitive member 3 as an image carrier, a charging device 2 for charging the surface of the photosensitive member 3, a developing device 5 as a developing unit, and a cleaning device 7 for cleaning the photosensitive member 3.

  The image forming unit 200 includes a writing unit 100 for writing an electrostatic latent image on the photosensitive member 3 and an intermediate transfer belt 16 to which a toner image formed on the photosensitive member 3 is transferred. The image forming apparatus further includes a primary transfer roller 6 that faces the photosensitive member 3 and the intermediate transfer belt 16 to form a primary transfer nip, and primarily transfers the toner image on the photosensitive member 3 to the intermediate transfer belt 16. Further, a secondary transfer roller 26 is provided to transfer the toner image on the intermediate transfer belt 16 to a transfer sheet S as a recording material. On the upstream side of the transfer direction of the transfer sheet S with respect to the secondary transfer nip formed by the secondary transfer roller 26 and the intermediate transfer belt 16, a registration roller pair 12 is provided for causing the transfer sheet S to temporarily stand by.

  The image forming unit 200 includes four toner bottles 20 (Y, M, C, K) for storing replenishment toner to be replenished to the developing devices 5 (Y, M, C, K) consuming the toner. Further, a fixing device 9 as a fixing unit is provided above the secondary transfer roller 26, and a sheet discharge roller 18 is provided on the downstream side of the fixing device 9 in the conveyance direction of the transfer sheet S.

  The sheet feeding section 400 has a sheet feeding cassette 10 as a recording material storage section and a sheet feeding roller 11, and the sheet feeding cassette 10 stacks the transfer sheet S on the stacking surface. The sheet feeding roller 11 is for separating and feeding the transfer sheets S stacked on the sheet feeding cassette 10 one by one.

  The reading unit 300 includes a contact glass 31 on which a document is placed. Further, in order to read and scan an original placed on the contact glass 31, a first traveling body 32 provided with an original illumination light source 32a and a first mirror 32b, a second mirror 35a, and a third mirror 35b are provided. And a second traveling body 35 provided. Furthermore, the lens 33 and the CCD 34 disposed behind the lens 33 are provided.

Next, the image forming operation of the MFP 500 will be described.
When the document is placed on the contact glass 31 and the image forming operation is started, the document illumination light source 32 a emits light. The reflected light obtained by reflecting the irradiated light on the document reflects the first mirror 32b, the second mirror 35a, and the third mirror 35b, passes through the lens 33, and enters the CCD 34. The reading unit 300 generates image information to be formed on the transfer sheet S based on the reflected light received by the CCD 34.

  In the image forming unit 200, the photosensitive member 3 is uniformly charged by the charging device 2 during rotation. Next, the writing unit 100 is driven based on the image information generated by the reading unit 300. In the writing unit 100, the light source emits irradiation light, and the irradiation light scans the surface of the photosensitive member 3, whereby an electrostatic latent image is formed on the charged area (image forming area) of the photosensitive member 3. The electrostatic latent image is developed by a developer (toner) supplied from the developing roller 15 of the developing device 5 to become a toner image as a visible image.

  On the other hand, while the toner image is being formed on the photosensitive member 3, the transfer sheet S is pulled out by the sheet feeding roller 11 from the selected one of the plurality of sheet feeding cassettes 10 and the leading edge thereof is It stands by in a state of being in contact with the nip portion of the registration roller pair 12. Then, the registration roller pair 12 starts to rotate at the timing of being superimposed on the toner image transferred so that the toner image of each color is superimposed on the intermediate transfer belt 16 from on the photosensitive member 3 in the primary transfer nip. , The transfer sheet S is fed to the secondary transfer nip. The transfer paper S to which the toner image has been transferred at the secondary transfer nip is discharged by contact with a discharge brush, mechanically separated from the intermediate transfer belt 16, and then sent to the fixing device 9.

The fixing device 9 includes two rollers forming a fixing nip so as to press-contact and rotate the transfer sheet S across the conveyance path of the transfer sheet S, and the transfer sheet S is heated by sandwiching the transfer sheet S between the two rollers. At the same time, pressure is applied to fix the toner image on the transfer sheet S. The transfer sheet S having the toner image fixed by passing through the fixing device 9 is discharged onto the sheet discharge tray 8 by the sheet discharge roller 18.
The residual toner remaining on the surface of the photosensitive member 3 after passing through the primary transfer nip is removed from the photosensitive member 3 by the cleaning device 7 and collected.

  In the above description, the image information of the document placed on the contact glass 31 is read by the reading unit 300, and the function as the copying machine of the multi-function device 500 that forms an image based on the image information has been described. The multifunction peripheral 500 has not only a function as a copying machine but also a function as a printer that forms an image based on image information input from an external electronic device such as a personal computer.

  In the MFP 500, which is the image forming apparatus of the embodiment, the latent image formed on the photosensitive member 3 is developed to form a visible toner image, and then the intermediate transfer belt 16 as an intermediate transfer member After the toner image is transferred onto the transfer sheet S, the toner image on the transfer sheet S is fixed to obtain an image. The method of transferring the toner image to the transfer sheet S is not limited to the intermediate transfer method via the intermediate transfer member, and may be a direct method of transferring the toner image to the transfer sheet S directly from the photosensitive member. In a direct transfer type color image forming apparatus, a latent image formed on each photosensitive member is developed into a visible image, and then a transfer material such as a recording sheet carried on a transfer conveying belt is used as each photosensitive member. To the transfer unit of A visible image of each color formed on each photosensitive member is superposed on and transferred onto a transfer material, and the visible image transferred onto the transfer material is fixed to obtain an image.

Next, the write unit 100 will be described.
FIG. 3 is a schematic block diagram of the writing unit 100 of the present embodiment provided in the multifunction peripheral 500. As shown in FIG. In the multi-function device 500 shown in FIG. 2, the writing unit 100 is arranged to be inclined, but in FIG.

  The writing unit 100 has a reflecting mirror on the side of a regular polygon that rotates at high speed, and includes a polygon scanner 56 that deflects laser light incident on the reflecting mirror to scan. Further, the installation portion of the polygon scanner 56 is a sealed space, and a soundproof glass 55 is provided to suppress noise when the polygon scanner 56 is driven to rotate the reflection mirror. Further, it is an imaging optical element, and is made of a resin scanning lens 57 having an fθ correction function, and a first reflection mirror 80 and a second reflection mirror 81 for guiding the laser light passing through the scanning lens 57 to the photosensitive member 3. And.

The writing unit 100 includes a housing 101, which is an optical housing that forms an optical box that is a resin-made holding body on which the above-described members are disposed, and an upper cover 102 and a lower cover 103 for sealing the housing 101. Prepare. "13" in FIG. 3 shows the optical path of the laser beam which exposes the photoreceptor 3 of each color.
In the writing unit 100, a dustproof glass 59 for preventing the falling of dust or the like into the housing 101 is disposed at the opening of the upper cover 102 through which the laser beam 13 passes. The member through which the laser beam 13 disposed in the opening of the upper cover 102 is transmitted is not limited to a flat glass member such as the dustproof glass 59. As long as the laser beam 13 can be transmitted and the dust and the like can be prevented from falling into the housing 101, the shape may be other than a flat shape, and a material such as a resin other than glass may be used.

FIG. 4 is an enlarged perspective view of the vicinity of the polygon scanner 56 of the writing unit 100. As shown in FIG.
As shown in FIG. 4, the writing unit 100 includes a light source unit 51, and as a pre-polygon optical system installed in a path of the laser light 13 from the light source unit 51 to the polygon scanner 56, a coupling lens 52, an aperture 53, and A cylindrical lens 54 is provided. The light source unit 51 can use a semiconductor laser as a light source, but the light source is not limited to this.

The laser light 13 entering the polygon scanner 56 is emitted from the light source unit 51, converted from a divergent light beam to a parallel light beam by the coupling lens 52, and shaped by the aperture 53. Next, the laser beam 13 is condensed in the sub-scanning direction by the cylindrical lens 54, passes through the soundproof glass 55, and is incident on the polygon scanner 56. The laser beam 13 incident on the polygon scanner 56 is deflected and directed to the scanning lens 57.
The laser beam 13 transmitted through the scanning lens 57 is reflected by the first reflection mirror 80 and the second reflection mirror 81 as shown in FIG. 1 and transmitted through the dustproof glass 59 to expose the surface of the photosensitive member 3.

The coupling lens 52 and the cylindrical lens 54 are fixed to the housing 101 with an adhesive after adjustment so as to obtain desired optical characteristics. Further, the light source unit 51, the aperture 53, the soundproof glass 55, the polygon scanner 56, the scanning lens 57, the first reflection mirror 80 and the second reflection mirror 81 are also fixed to the housing 101.
As described above, the components of the optical system are attached to the housing 101 which is a single housing, and the upper cover 102 and the lower member which is the cover member of the housing 101 do not adhere dust and dirt to the components of the optical system. It is covered by a cover 103. Furthermore, dustproof glass 59 is installed in the opening provided in the upper cover 102 which is an optical path through which the laser beam 13 passes, and the laser beam 13 is irradiated to the photosensitive member in a state in which the space where components of the optical system are disposed is sealed. It is a structure.

  The writing unit 100 according to the present embodiment is an optical scanning device used in the multi-function device 500 that is a color image forming device, and includes a plurality of light source units 51, a scanning lens 57, and the like so as to face each color. ing. In the present embodiment, the plurality of light source units 51, the scanning lens 57, and the like are accommodated in the housing 101 which is a single housing.

In the writing unit 100, in addition to the laser beam 13 for forming a latent image on the photosensitive member 3, so-called flare which is deviated from the regular optical path by surface reflection of the optical element from the light source 51 to the photosensitive member 3. Light may occur. When the flare light reaches the photosensitive member 3 and the surface of the photosensitive member 3 is exposed, an abnormal image such as a longitudinal stripe is formed.
As a countermeasure, by providing a shield on the light path of flare light, it is possible to shield the exposure to the photosensitive member 3. As a method of providing a shield, when the shield is attached on the scanning lens 57, stress is applied to the scanning lens 57 when the temperature rises due to the difference in linear expansion coefficient between the scanning lens 57 and the shield, and the profile of the scanning line changes. There is a risk of

FIG. 5 is a perspective view showing an optical path in which the reflected light from the soundproof glass 55 enters the scanning lens 57 as flare light 13a.
The laser beam 13 transmitted through the cylindrical lens 54 is incident on the soundproof glass 55. Since the soundproof glass 55 has a transmittance of 80% or more, most of the incident laser light 13 is transmitted as shown by a broken line in FIG. However, as shown by the solid arrows in FIG. 5, a part of the laser light 13 which is not transmitted is reflected on the surface of the soundproof glass 55 to become flare light 13a.

FIG. 6 is a side cross-sectional view of the scanning lens 57 showing an optical path until the flare light 13a enters the scanning lens 57 and is emitted.
As shown in FIG. 6, the flare light 13a reflected by the soundproof glass 55 is incident on the scanning lens 57 and is detected by the sinking portion 41 of the scanning lens upper surface 57a, the scanning lens emission surface 57b, and the sinking portion 41 of the scanning lens lower surface 57c. Each is reflected. Then, the light is emitted from the scanning lens upper surface 57a or the scanning lens incident surface 57d. FIG. 6 shows an example in which the flare light 13a is emitted from the scanning lens upper surface 57a.

FIG. 7 is an enlarged cross-sectional view of the writing unit 100 showing a state in which the flare light 13a emitted from the scanning lens upper surface 57a passes through the dustproof glass 59. As shown in FIG.
As shown in FIG. 7, when the flare light 13a emitted from the upper surface 57a of the scanning lens passes through the dustproof glass 59, the flare light 13a reaches the surface of the photosensitive member 3 disposed above the writing unit 100, The surface of the body 3 is exposed. As a result, a range different from the range to be exposed based on the image information on the surface of the photosensitive member 3 is exposed to generate an abnormal image.
In FIGS. 6 and 7, hatching indicating the cross section of the scanning lens 57 is not shown for convenience, for convenience of showing the path of the flare light 13a in the scanning lens 57 by the arrow.

FIG. 1 is an enlarged explanatory view of the vicinity of the scanning lens 57 and the dustproof glass 59 of the writing unit 100 of the present embodiment. An area α surrounded by a broken line in FIG. 1 is an area through which flare light 13a emitted from the upper surface 57a of the scanning lens passes from the dustproof glass 59 toward the photosensitive member 3. As shown in FIG. 1, the writing unit 100 of the present embodiment includes a light shielding member 61 that shields a part of the region α between the scanning lens upper surface 57 a and the dustproof glass 59.
As shown in FIG. 1, by disposing a part of the light shielding member 61 between the scanning lens 57 and the dustproof glass 59, it is possible to shield the flare light 13a from the scanning lens 57 toward the photosensitive member 3 . That is, it is possible to shield the flare light 13 a that is emitted from the scanning lens 57, transmitted through the dustproof glass 59, and emitted to the outside of the writing unit 100 and directed to the light path reaching the photosensitive member 3.

FIG. 8 is an enlarged perspective view of the vicinity of the mounting position of the light shielding member 61 before the light shielding member 61 is attached in the writing unit 100. FIG. 9 is a light shielding member 61 in the state where the light shielding member 61 in the writing unit 100 is attached. It is an expansion perspective view of the neighborhood.
The light shielding member 61 is a black polyester film with a thickness of about 0.1 mm and hardly transmits light.

  The double-sided adhesive tape 63 is used to fix the light shielding member 61 to the housing 101, and the double-sided adhesive tape 63 is attached to the light shielding member 61 only at a portion to be attached to the housing 101. On the housing 101 side, the upper surface of the rib 105 at a position slightly higher than the scanning lens upper surface 57a is used as a bonding surface 105a.

As shown in FIGS. 8 and 9, the attachment position 61a is determined using the rib 105 as the attachment reference 105b.
As shown in FIGS. 1 and 9, one end of the light shielding member 61 is fixed to the housing 101 with double-sided tape, and the other end side which is a free end not fixed is a position facing the scanning lens upper surface 57a. It is arranged.
Further, as shown in FIG. 9, the light shielding member 61 has a shape in which the width increases from the middle toward the free end to the free end from the fixed end side, and the two corner portions 62 on the free end scan It is disposed above the lens 57.

  The width of the rib 105 to which the light shielding member 61 is fixed can be narrowed by making the width on the fixed portion side narrower than the free end side, and the rib located outside the path of the laser beam 13 for latent image formation Even if the light shielding member 61 is fixed to the portion 105, the enlargement of the device can be suppressed. Further, by making the width at the free end side wider than the fixed portion side, the width at the free end side of the light shielding member 61 can be made larger than the range through which the flare light 13a passes, and the flare light 13a has a margin. Can be shielded.

  The laser beam 13 for forming a latent image is incident from the scanning lens incident surface 57d, passes through the scanning lens 57, and is emitted from the scanning lens emission surface 57b. For this reason, in the writing unit 100 of the present embodiment in which the free end of the light shielding member 61 faces the scanning lens upper surface 57a, one of the light shielding members 61 is perpendicular to the transmission direction of the laser light 13 in the scanning lens 57. The unit is located. The light emitted in the direction orthogonal to the transmission direction of the laser light 13 is flare light 13a that does not contribute to latent image formation. By positioning a part of the light shielding member 61 in the outgoing direction, it is possible to realize a configuration in which the upper surface 57a of the scanning lens from which only the flare light 13a is emitted is covered with the light shielding member.

As shown in FIG. 1, since the affixing surface 105a is slightly higher than the scanning lens upper surface 57a, the light shielding member 61 does not contact the scanning lens 57 and is slightly floating.
The light shielding member 61 is disposed such that the scanning lens 57 is slightly floating, and the corner 62 of the light shielding member 61 is positioned above the scanning lens 57. With such an arrangement, even if the light shielding member 61 is not fixed to the affixing surface 105a by the double-sided tape 63, the light shielding member 61 is the upper surface (the affixing surface 105a) of the rib 105 and the scanning lens upper surface 57a. Is held between two Therefore, when the fixing is released, it is possible to prevent the light shielding member 61 from entering between the scanning lens incident surface 57d of the scanning lens 57 and the soundproof glass 55 and shielding the laser beam 13 for latent image formation.

  In addition, with the above-described arrangement, even if the light blocking member 61 is deformed with time due to thermal contraction, moisture absorption or the like, the light blocking member 61 will not be lower than the scanning lens upper surface 57a. For this reason, even if fixed in a cantilever state, it is possible to prevent the light shielding of the laser beam 13 for latent image formation.

  In addition, even if the fixed part side faces the scanning lens upper surface 57a with respect to the free end of the light shielding member 61 including the corner part 62 and the free end protrudes to a position not facing the scanning lens upper surface 57a, flare emitted from the scanning lens upper surface 57a The light 13a can be blocked. However, in this case, when the free end side of the light shielding member 61 is displaced downward toward the scanning lens 57 due to the fixation by the double-sided adhesive tape 63 being released or the light shielding member 61 being deformed with time, The fixed part side contacts the scanning lens upper surface 57a rather than the end. At this time, the free end of the light shielding member 61 protruding to the opposite side to the fixed part sandwiching the scanning lens 57 hangs downward below the contact part with the scanning lens upper surface 57a and is opposed to the scanning lens emission surface 57b. It may reach and block the laser beam 13 for latent image formation.

On the other hand, in the present embodiment, since the free end of the light shielding member 61 including the corner 62 faces the scanning lens upper surface 57a, even if the free end of the light shielding member 61 is displaced downward toward the scanning lens 57, the light shielding member The free end of the lens 61 abuts on the upper surface 57a of the scanning lens. Therefore, a part of the light blocking member 61 does not reach below the upper surface 57a of the scanning lens, and the light blocking member 61 can be prevented from blocking the laser beam 13 for forming the latent image.
As shown in FIGS. 1 and 9, the free end of the light shielding member 61 faces the scanning lens upper surface 57a, but if at least a part of the free end faces the scanning lens upper surface 57a, the other part is the scanning lens Even if it protrudes from the upper surface 57a, it is possible to suppress light shielding when it hangs down.

The double-sided adhesive tape 63 is attached only to the portion in contact with the housing 101. Even if foreign matter such as dust or lint adheres to the double-sided adhesive tape 63, there is no risk of blocking the laser beam 13 for latent image formation. .
In the present embodiment, a polyester film is used as the light shielding member 61. However, the light shielding member 61 is not limited to this, and a plate-like resin member or a metal member may be used.

  The scanning lens 57 of this embodiment uses a molded part of resin. The optical surface (lens surface) of the scanning lens 57, that is, the scanning lens output surface 57b through which the laser light 13 passes and the scanning lens incident surface 57d are required to have a high-accuracy shape with few errors. On the other hand, the scanning lens upper surface 57a and the scanning lens lower surface 57c are not functionally used. Therefore, at the time of molding, the upper surface 57a of the scanning lens and the lower surface 57c of the scanning lens are cooled to form sink marks 41 (see FIG. 6 etc.) intentionally on the upper surface 57a of the scanning lens and lower surface 57c of the scanning lens. The lens surface of the mold used is transferred to the molded part with high accuracy.

  Since the scanning lens upper surface 57a and the scanning lens lower surface 57c of the scanning lens 57 have sinks as described above, their shapes are dispersed due to molding lot difference and mold cavity difference. Therefore, the light path of the flare light 13a transmitted or reflected by the scanning lens upper surface 57a and the scanning lens lower surface 57c becomes uneven.

  In the present embodiment, in consideration of such variations, the free end side of the light shielding member 61 is made larger than the range through which the flare light 13a passes, in consideration of an allowance. As described above, when the light shielding member 61 enlarges the light shielding portion, the flare light 13a is easily shielded. However, when the light shielding member 61 is not fixed, the light shielding member 61 receives the laser light 13 for forming a latent image. There is a risk of blocking light. On the other hand, by arranging the corner portion 62 of the light shielding member 61 to be positioned above the scanning lens 57, it is possible to prevent the laser light 13 for forming the latent image from being shielded. Thus, in the writing unit 100 according to the present embodiment, the light shielding member 61 can shield the flare light 13a, and the laser light 13 for forming the latent image can not be shielded.

  Further, in the present embodiment, the light shielding member 61 is fixed not to the scanning lens 57 but to the housing 101. As described above, by fixing the light shielding member 61 to the housing 101 side, the influence on the scanning lens 57 is suppressed. When the double-sided adhesive tape 63 is attached to the scanning lens 57, the expansion amount at the time of temperature rise differs depending on the difference in linear expansion coefficient, and thermal stress is applied to the scanning lens 57. The thermal stress applied to the scanning lens 57 affects the deformation of the lens surface, resulting in a change in the scanning position on the surface of the photosensitive member 3 which is a surface to be scanned. In the color image forming apparatus, the scanning position change becomes a color shift due to the scanning position shift between colors, and the image quality is degraded. In the present embodiment, since the light shielding member 61 is fixed on the side of the housing 101, the above-described problems do not occur.

  Further, in the present embodiment, the light shielding member 61 is fixed to the housing 101 by a cantilever structure. If fixed by supporting both ends, the following problems may occur due to the difference in linear expansion coefficient between the light shielding member 61 and the housing 101. That is, when thermally expanded, a difference may occur between the distance between the fixed locations at both ends of the light shielding member 61 and the distance between the fixed locations in the housing 101. Thus, when a difference occurs between the distance between the fixed locations and the distance between the fixed locations, thermal stress occurs in the light shielding member 61 and the housing 101. When the housing 101 is deformed due to this thermal stress, the positions of the components of the optical system fixed to the housing 101 may change, which may cause a change in the scanning position on the surface of the photosensitive member 3 which is a surface to be scanned.

In the present embodiment, since the light blocking member 61 is fixed to the housing 101 in a cantilevered manner, thermal stress does not occur in the light blocking member 61 and the housing 101, and the above-described problems do not occur.
In the present embodiment, the light shielding member 61 has a cantilever structure with respect to the housing 101, but it is sufficient that only one end of the light shielding member 61 is fixed to the housing 101. For example, the other end opposite to the fixed end of the light shielding member 61 is in contact with a part of the housing 101 other than the structure having the scanning lens upper surface 57a in contact and supported or the rib 105 having the affixing surface 105a. The lower end of the other end may be supported as in the supported structure.

  In the multi-function device 500 including the writing unit 100 having the above-described configuration, the light shielding member 61 blocks the flare light 13a, whereby the flare light exposes the surface of the photosensitive member 3 and an abnormal image such as a vertical stripe is generated. It can prevent the occurrence. Furthermore, since stress is not generated in the housing 101 due to the provision of the light shielding member 61, it is possible to prevent occurrence of positional deviation of an image caused by deformation of the housing 101 due to stress.

  By taking the above configuration, when α in FIG. 1 becomes an optical path where the flare light 13a due to the surface reflection of the soundproof glass 55 reaches the photosensitive member 3, even if the optical path of the flare light 13a varies, It can shield light. Further, by fixing the light shielding member 61 to the housing 101, the fixing of the light shielding member 61 does not affect the scanning lens 57.

Furthermore, when the fixing deterioration with time or the deformation of the light shielding member 61 occur, the corner 62 serving as the free end of the light shielding member 61 may be displaced downward, that is, may be displaced to the scanning lens 57 side. Even if such a displacement occurs, in the present embodiment, the corner 62 abuts on the scanning lens upper surface 57 a and is not displaced further downward. Accordingly, it is possible to prevent the light shielding member 61 from facing the scanning lens emission surface 57b or the scanning lens incident surface 57d, and to prevent the light shielding member 61 from shielding the laser light 13 passing through these surfaces. Therefore, even if the fixing deterioration with time or the deformation of the light shielding member 61 occur, the light shielding member 61 can shield only the flare light 13 a without shielding the laser light 13 for forming the latent image.
Therefore, it is possible to realize an image forming apparatus capable of outputting a high quality image without an abnormal image due to the flare light 13a.

  In the writing unit 100 according to the present embodiment, the flare light 13a reflected by the soundproof glass 55 is incident on the scanning lens 57, and then is reflected internally and is in the width direction of the scanning lens 57 (front far side in FIG. 5). Emit from the end of the For this reason, only the vicinity of the end in the width direction of the scanning lens upper surface 57 a is covered with the light shielding member 61. When flare light 13a is emitted from the vicinity of the central portion in the width direction of scanning lens 57, the length of light shielding member 61 is increased to cover the vicinity of the central portion in the width direction of scanning lens 57 or scanning The entire area in the width direction of the lens 57 may be covered.

In the embodiment described above, the case has been described in which the optical system constituent member that emits the flare light 13 a shielded by the light shielding member 61 is the scanning lens 57 that is an imaging optical element. The optical system constituent member for emitting the flare light 13 a shielded by the light shielding member 61 is not limited to the scanning lens. It is a member that forms an optical system such as various lenses and mirrors, and may be a member that emits light (flare light) directed to a path different from a predetermined path.
In the above-described embodiment, the outline of the tandem color image forming apparatus is shown, but the image forming apparatus is not limited to the tandem color image forming apparatus, and is effective also in a monochrome image forming apparatus.

The above-described one is an example, and each mode has the unique effect.
(Aspect A)
An optical system component such as a scanning lens 57 constituting a part of an optical system through which a light beam such as the laser beam 13 passes, a holder such as a housing 101 for holding the optical system, and light emitted from the optical system component In an optical scanning apparatus such as a writing unit 100 having a light blocking member such as a light blocking member 61 that blocks light such as flare light 13a directed to a path different from the predetermined path, only one end of the light blocking member is held. Fix it against your body.
According to this, as described in the above embodiment, by fixing only one end of the light shielding member to the holder, a difference in the amount of expansion at the time of thermal expansion occurs between the light shielding member and the holder. Even in this case, no stress acts on the holder. Therefore, stress can be prevented from acting on the holder due to the provision of the light shielding member in the optical scanning device.

(Aspect B)
In the embodiment A, a dustproof glass made of a cover member such as the upper cover 102 covering the holding body such as the housing 101 etc. and a material through which light rays such as the laser light 13 are transmitted And a part of the light shielding member such as the light shielding member 61 is located between the optical system constituting member such as the scanning lens 57 and the opening light transmitting member.
According to this, as described in the above embodiment, the optical system component is emitted, the opening light transmitting member is transmitted, and the light is emitted to the outside of the light scanning device such as the writing unit 100, etc. It is possible to block the light such as the flare light 13a or the like directed to the light path reaching the irradiation target.

(Aspect C)
In any of the modes A and B, a part of the light blocking member such as the light blocking member 61 is close to and opposed to the optical system component such as the scanning lens 57.
According to this, as described in the above embodiment, it is possible to block the light to be blocked such as the flare light 13a emitted from the position facing the light blocking member in the optical system constituent member. In addition, even if deterioration of fixation over time or deformation of the light shielding member occurs, the light shielding member abuts the optical system constituting member, and the surface of the surface of the optical system constituting member other than the surface emitting light to be shielded It can prevent that a member opposes. Thus, it is possible to prevent the light blocking member from blocking the light beams passing through the surfaces other than the surface that emits the light to be blocked.

(Aspect D)
In any of the modes A to C, at least a part (corner portion 62 or the like) of the free end of the cantilever structure of the light blocking member such as the light blocking member 61 faces the optical system component such as the scanning lens 57.
According to this, as described in the above embodiment, even if the light blocking member is displaced toward the optical system component side, the light blocking member blocks light such as the laser beam 13 for forming the latent image. Side effects resulting from the provision of the members can be suppressed.

(Aspect E)
In any of the embodiments A to D, the optical system component is a light transmitting member such as the scanning lens 57 through which the light beam such as the laser light 13 passes, and is orthogonal to the light transmitting direction in the light transmitting member In the direction (upward direction), a part of the light shielding member such as the light shielding member 61 is positioned.
According to this, as described in the above embodiment, a configuration is realized in which the light shielding member covers the surface that emits only light to be shielded, such as flare light 13a that does not contribute to latent image formation in the optical system transmission member. Can.

(Aspect F)
In any one of the aspects A to E, the fixing location (pasting surface 105 a or the like) of the light blocking member such as the light blocking member 61 to the holder such as the housing 101 is more than the top surface of the optical system component such as the scanning lens 57 or the like. It is the upper side, and a part of the light blocking member faces the upper surface of the optical system component.
According to this, as described in the above embodiment, it is possible to realize the configuration in which the light shielding member is disposed so as to cover the upper surface of the optical system configuration member.

(Aspect G)
In any one of the aspects A to F, the light blocking member such as the light blocking member 61 blocks the light to be blocked such as the flare light 13a more than the portion fixed to the holder such as the housing 101 In the vicinity of the corner portion 62, etc., the shape is wider.
According to this, as described in the above embodiment, it is possible to shield the light to be shielded which does not contribute to the latent image formation with a margin while suppressing the enlargement of the apparatus.

(Aspect H)
In any of the embodiments A to G, the light shielding member such as the light shielding member 61 is fixed by an adhesive tape such as a double-sided tape 63, and the adhesive tape is a portion that shields light to be shielded such as flare light 13a. It is pasted only to a part of the others.
According to this, as described in the above embodiment, even if foreign matter is attached to the adhesive tape, it is possible to suppress the side effect that the foreign matter blocks the light beam such as the laser beam 13 for forming the latent image.

(Aspect I)
A latent image was formed on the surface of the latent image carrier by irradiating a light beam such as a laser beam 13 onto the surface of the latent image carrier such as the photosensitive member 3 using a light scanning means, and obtained by developing the latent image. In an image forming apparatus such as a multifunction machine 500 that forms an image by finally transferring the image onto a recording material such as transfer paper S, writing according to any one of the modes A to H as light scanning means An optical scanning device such as the unit 100 is used.
According to this, as described in the above embodiment, generation of an abnormal image caused by the light to be shielded such as flare light 13a not contributing to latent image formation exposing the surface of the latent image carrier is prevented it can. Furthermore, it is possible to prevent the occurrence of positional deviation of the image due to the provision of the light shielding member. Thus, high quality images can be obtained.

DESCRIPTION OF SYMBOLS 1 image forming device 2 charging device 3 photosensitive member 5 developing device 6 primary transfer roller 7 cleaning device 8 sheet discharging tray 9 fixing device 10 sheet feeding cassette 11 sheet feeding roller 12 registration roller pair 13 laser beam 13 a flare light 15 developing roller 16 intermediate Transfer belt 18, paper discharge roller 20, toner bottle 26, secondary transfer roller 31, contact glass 32, first traveling body 32a, light source for document illumination 32b, first mirror 33, lens 35, second traveling body 35a, second mirror 35b, third mirror 41 sinking portion 51 Light source unit 52 Coupling lens 53 Aperture 54 Cylindrical lens 55 Soundproof glass 56 Polygon scanner 57 Scanning lens 57a Scanning lens upper surface 57b Scanning lens output surface 57c Scanning lens lower surface 57d Scanning lens incident surface 59 Dustproof glass 61 Light shielding member 61a Bonding position 62 Angle 63 double-sided adhesive tape 80 first reflection mirror 81 second reflection mirror 100 writing unit 101 housing 102 upper cover 103 lower cover 105 rib 105 a attachment surface 105 b attachment reference 200 image forming unit 300 reading unit 400 sheet feeding unit 500 multifunction machine S Transfer paper

Patent No. 4925623

Claims (9)

An optical system component that constitutes a part of an optical system through which a light beam passes;
A holder for holding the optical system;
A light shielding member that shields light traveling toward a path different from a predetermined path among the light emitted from the optical system constituent member;
Only one end of the light shielding member is fixed to the holding body ,
The light scanning device is characterized in that the fixing position of the light shielding member to the holding body is above the upper surface of the optical system component, and a part of the light shielding member faces the upper surface of the optical system component. .   An optical system component that constitutes a part of an optical system through which a light beam passes;
  A holder for holding the optical system;
  A light shielding member that shields light traveling toward a path different from a predetermined path among the light emitted from the optical system constituent member;
  The optical scanning is characterized in that only one end of the light shielding member is fixed to the holding body with an adhesive tape, and the adhesive tape is attached only to a part other than the portion where the light shielding member shields light. apparatus. The optical scanning device according to any one of claims 1 and 2 .
A cover member covering the holding body;
And an opening light transmitting member made of a material through which light is transmitted and closing an opening through which the light provided in the cover member passes;
A part of the light shielding member is located between the optical system component and the opening light transmitting member.   In the optical scanning device according to claim 3,
  The light scanning device according to claim 1, wherein the opening light transmission member is dustproof glass. The optical scanning device according to any one of claims 1 to 4 .
A part of the light blocking member is close to and opposed to the optical system component. The optical scanning device according to any one of claims 1 to 5.
An optical scanning device, wherein at least a part of the free end of the cantilever structure of the light shielding member faces the optical system component. The optical scanning device according to any one of claims 1 to 6.
The optical system component is a light transmitting member through which light is transmitted,
A part of the light shielding member is located in a direction orthogonal to the light transmitting direction of the light transmitting member . The optical scanning apparatus according to any one of 請 Motomeko 1 to 7,
The light scanning device according to claim 1, wherein the light blocking member has a shape in which a portion that blocks light is wider than a portion fixed to the holding body. The surface of the latent image carrier is irradiated with a light beam using a light scanning means to form a latent image on the surface of the latent image carrier, and an image obtained by developing the latent image is finally formed on the recording material. In an image forming apparatus for forming an image by transferring
An image forming apparatus using the light scanning device according to any one of claims 1 to 8 as the light scanning means.

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