JP2016051040A - Dustproof device for light-emitting unit and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dustproof device for a light-emitting unit capable of facilitating the cleaning of a dustproof glass and further, preventing reduction in attachment position accuracy and sealability.SOLUTION: The dustproof device for a light-emitting unit includes a light-emitting unit 40 which emits light from the opening H1 of a housing 41, a stay 50 which has a window part H2 corresponding to the opening H1, a seal member 52 which is provided over the peripheral edge part 50b of the window part H2, and a dustproof glass 51 which is formed smaller than the seal member 52 and held between the housing 41 and the stay 50 through the seal member 52, to close the opening H1. The housing 41 includes an inner peripheral side pressing surface 41a which presses the peripheral edge part of the dustproof glass 51, to compress the inner peripheral side part a of the seal member 52 and an outer peripheral side pressing surface 41b which compresses the outer peripheral side part b projected from the dustproof glass 51 of the seal member 52 with a compression width larger than the inner peripheral side part a.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a dust-proof device for a light emission unit that forms an electrostatic latent image by irradiating light to a charged photoreceptor such as a photosensitive drum, and an image forming apparatus including the dust-proof device.

  In an electrophotographic image forming apparatus such as a copying machine or a printer, a light emitting unit (laser scanner unit) that forms an electrostatic latent image by exposing the surface of a charged photosensitive drum is known (Patent Document 1). reference).

  In this device, a light source, a rotating polygon mirror (polygon mirror), an fθ lens, a folding mirror, and the like are housed in a housing. The light emitted from the light source is reflected by the rotary polygon mirror, further reflected by the folding mirror, exits from the opening of the housing, and irradiates the photosensitive drum. A dust-proof glass is fitted in the opening to prevent foreign matter such as dust from entering the housing. That is, the dust-proof glass is incorporated in the housing as part of the light emission unit.

  On the other hand, some dustproof glasses are provided separately from the light emitting unit without being incorporated into the light emitting unit.

JP 2007-233137 A

  In the light emission unit of the above-mentioned Patent Document 1, since dust-proof glass is fitted into the housing and integrated integrally, it is necessary to ensure high installation position accuracy and sealing (dust-proof) of the dust-proof glass with respect to the housing. Can do. However, if the dust-proof glass is inadvertently touched when the dust-proof glass is fitted into the housing and the inside of the dust-proof glass becomes dirty, there is a problem that cleaning is difficult.

  On the other hand, when the dustproof glass is provided separately from the light emitting unit, the dustproof glass can be cleaned by removing the light emitting unit, but the mounting position accuracy and sealing performance (dustproofness) are inferior. There's a problem.

  The present invention is capable of cleaning a transparent member (dust-proof glass), and further, a dust-proof device for a light-emitting unit capable of suppressing deterioration in mounting position accuracy and sealing property (dust-proof property) of the transparent member, and An image forming apparatus is provided.

  A dustproof device for a light emitting unit according to the present invention is provided over a light emitting unit that emits light from an opening of a housing, a mounting member having a window corresponding to the opening, and a peripheral portion of the window. A sealing member, and a transparent member that is formed smaller than the sealing member and is sandwiched between the casing and the mounting member via the sealing member to close the opening, and the casing includes: An inner peripheral side pressing surface that compresses an inner peripheral side portion of the seal member by pressing a peripheral portion of the transparent member, and an outer peripheral side portion that protrudes from the transparent member of the seal member, And an outer peripheral pressing surface that compresses with a larger compression width.

  An image forming apparatus of the present invention includes a photoconductor, and a dustproof device of the above light emission unit as a light emission unit that irradiates light to the charged photoconductor to form an electrostatic latent image. It is characterized by that.

  According to the dust-proof device of the light emission unit of the present invention, the transparent member is configured separately from the light emission unit. For example, the inner surface of the transparent member can be cleaned by removing the light emission unit. Is possible. Moreover, the inner peripheral side pressing surface of a housing | casing compresses the inner peripheral side part of a sealing member via this peripheral part by pressing the peripheral part of a transparent member. Thereby, a transparent member is pressed by the inner peripheral side press surface of a housing | casing with the reaction force (restoring force) of the inner peripheral side part of the compressed seal member. For this reason, the transparent member is brought into close contact with the inner peripheral pressing surface of the casing and is positioned with high accuracy following the inner peripheral pressing surface. Furthermore, since the outer peripheral side portion that protrudes from the transparent member is compressed with a larger compression width than the inner peripheral side portion by the outer peripheral side pressing surface of the housing, the seal member is pressed against the mounting member with a large force. Thereby, high airtightness and dustproofness can be ensured. Thus, according to the dustproof device of the present light emitting unit, it is possible to clean the inner surface of the transparent member, and furthermore, it is possible to ensure high mounting position accuracy, sealing performance, and dustproofness of the transparent member. .

  According to the image forming apparatus of the present invention, it is possible to ensure high sealing performance of the transparent member and to prevent the inner surface of the transparent member from becoming dirty. Further, since the inner surface of the transparent member can be cleaned, even when the transparent member is dirty, the stain can be easily removed. Furthermore, high mounting position accuracy of the transparent member can be ensured. Thereby, the light transmitted through the transparent member can be made clear and highly accurate, so that the electrostatic latent image formed on the photoconductor can be made good.

1 is a front view schematically showing a schematic configuration of an image forming apparatus. It is a perspective view which shows exposure apparatus and a photosensitive drum. FIG. 3 is an enlarged perspective view of a stay, a seal member, and dust-proof glass cut along a plane including an AA line in FIG. 2. FIG. 3 is an enlarged perspective view of a part of a stay, a seal member, dust-proof glass, and a housing, cut along a plane including an AA line in FIG. 2. FIG. 3 is an enlarged view taken along the line AA in FIG. 2 of a stay, a seal member, dustproof glass, and a part of a housing. (A), (B) is an AA arrow enlarged view in FIG. 2 explaining a mode that dustproof glass is engaged with the in-row part of a housing | casing.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
A first embodiment of the present invention will be described with reference to FIGS.

[Image forming apparatus]
A schematic configuration of the image forming apparatus 10 will be described with reference to FIG. FIG. 1 is a front view schematically showing a schematic configuration of the image forming apparatus 10. Here, the front view is a view as seen from the side where the user operates the image forming apparatus 10, that is, the side where the operation panel (not shown) or the like is present. For convenience of explanation, the description will be made assuming that the upper, lower, left, and right indicated by arrows on the upper left in FIG. 1 correspond to the upper, lower, left, and right of the image forming apparatus 10.

  In FIG. 1, an electrophotographic printer is illustrated as the image forming apparatus 10, but the present invention is not limited to this. For example, it may be a copying machine or a facsimile machine, or a printer, a copying machine, or a facsimile machine.

  As shown in FIG. 1, the image forming apparatus 10 forms an image on a sheet (recording material) P based on an image reading apparatus 11 that reads an image of a document D and image information read by the image reading apparatus 11. And an image forming unit 12. Further, the image forming apparatus 10 includes a sheet feeding / conveying device 13 that carries the sheet P into and out of the image forming unit 12.

  The image reading device 11 is disposed on the upper part of the image forming device 10, and includes a transparent document table glass 14, an openable / closable document pressing plate 15 that closely contacts the document D with the document table glass 14, and an image reading unit 16. And have. The image reading unit 16 is long in the main scanning direction (front-rear direction: arrow K1 direction in FIG. 2), and can move (run) in the sub-scanning direction (left-right direction: arrow K2 direction). The image reading device 11 reads an image of the document D on the document table glass 14 while the image reading unit 16 moves in the sub-scanning direction.

  The image forming unit 12 includes a photosensitive drum (photosensitive member) 20 that is driven to rotate in the direction of an arrow (clockwise in FIG. 1). Around the photosensitive drum 20, a charging roller 21, an exposure device 22, a developing roller 23, a transfer roller 24, and a cleaner 25 are disposed almost in order along the rotation direction. A fixing device 26 is disposed above (downstream side) the transfer roller 24.

  The surface of the photosensitive drum 20 (drum surface) is uniformly charged to a predetermined polarity and potential by the charging roller 21. An electrostatic latent image is formed on the drum surface after charging by the exposure device 22. The exposure device 22 emits a laser beam L that is controlled to be turned on / off based on the image information of the document D read by the image reading device 11 described above, exposes the drum surface to remove charges on the exposed portion, and An electrostatic latent image is formed. The electrostatic latent image is developed as a toner image with toner (developer) attached thereto by the developing roller 23. Thus, the toner image formed on the drum surface is transferred to the sheet P by the transfer roller 24.

  Here, the sheet P is conveyed by the sheet feeding / conveying device 13 in time with the toner image on the drum surface. The sheet feeding / conveying device 13 includes a sheet feeding cassette 30 in which a plurality of sheets P are stored in a stacked state, a pickup roller 31, a registration roller 32, a discharge roller 33, and a discharge tray 34. Only one sheet P in the sheet feeding cassette 30 is taken out by the pickup roller 31 and conveyed toward the registration roller 32. The conveyed sheet P is temporarily stopped by the registration roller 32 to correct skewing. This sheet P is supplied to the transfer nip portion at the timing when the toner image on the photosensitive drum 20 described above is conveyed to the transfer nip portion between the photosensitive drum 20 and the transfer roller 24, and the toner is transferred by the transfer roller 24. The image is transferred.

  The sheet P after the toner image is transferred is heated and pressed by the fixing device 26 to fix the toner image on the surface. After the toner image is transferred, the transfer residual toner remaining on the drum surface is removed by the cleaner 25, and the photosensitive drum 20 is used for the next image formation starting from charging. On the other hand, the sheet P after the toner image is fixed is discharged onto a discharge tray 34 by a discharge roller 33. Thus, image formation on one side (front surface) of one sheet P is completed.

[Dust-proof device for light emission unit]
FIG. 2 is a perspective view showing the exposure device 22 and the photosensitive drum 20. 3 is an enlarged perspective view of the stay (attachment member) 50, the seal member (elastic member) 52, and the dust-proof glass (transparent member) 51 cut along a plane including the line AA in FIG. . 4 is an enlarged perspective view of a part of the stay 50, the seal member 52, the dust-proof glass 51, and the housing 41 cut along a plane including the line AA in FIG. FIG. 5 is an enlarged view of the stay 50, the seal member 52, the dust-proof glass 51, and a part of the housing 41, as viewed from the AA line in FIG. 2. 6 (A) and 6 (B) are enlarged views taken along line AA in FIG. 2 for explaining how the dust-proof glass 51 is engaged with the in-row part 41d of the casing 41. FIG.

  As shown in FIG. 2, the exposure apparatus 22 includes a light emission unit 40, a stay (attachment member) 50, a dustproof glass (transparent member) 51, and a seal member (elastic member) 52 (see FIG. 3).

  The light emission unit 40 includes a casing 41 serving as a case, a motor (not shown) as a driving unit housed in the casing 41, and a rotating polygon mirror (polygon mirror). The housing 41 is formed with an opening H1 (see FIGS. 4 and 5). The opening H1 is formed in a rectangular shape corresponding to a window H2 of the stay 50 described later and is long in the main scanning direction, and is sealed by a dustproof glass 51 described later. In the light emitting unit 40, the rotating polygon mirror is driven to rotate by a motor, and light emitted from a light source (not shown) is deflected by the rotating polygon mirror and passes through (transmits) the dust-proof glass 51 that seals the opening H1. Let

  As shown in FIG. 2, the stay 50 is, for example, a member formed by bending a metal plate and extending in the main scanning direction (arrow K1 direction). The stay 50 is fixedly disposed at a predetermined position of a frame (not shown) of the image forming apparatus 10. The stay 50 is formed with a rectangular window H2 that is long in the main scanning direction (arrow K1 direction) at a position corresponding to the opening H1. The window H2 is formed larger than the opening H1, and light that has passed through the opening H1 is not blocked by the peripheral edge 50b (see FIG. 4) of the window H2 in the stay 50. It has come to pass.

  The seal member 52 is arranged in a frame shape on the back surface 50 a of the stay 50. The seal member 52 is formed in a frame shape so as to frame the peripheral edge 50b of the window H2 on the back surface 50a side of the stay 50 over the entire circumference. The seal member 52 is formed of, for example, an elastic member such as urethane foam that is easily elastically deformed, and is adhered along the peripheral edge 50b with an adhesive. Here, the seal member 52 is continuously provided on the upper side, the lower side, the left side, and the right side of the window portion H2 toward the window portion H2, but as shown in FIG. 3, the upper portion located on the upper side. The lower part 52B located on the lower side is formed thicker than 52A. This is because the dust-proof glass 51 is attached in an inclined posture with an inclination angle θ as shown in FIG. For this reason, the thickness Tb of the lower part 52B is thicker than the thickness Ta of the upper part 52A in the seal member 52 before compression (see the two-dot chain line) (Ta <Tb). In the following description, for convenience of description, a part located on the inner peripheral side of the frame-like seal member 52 is referred to as an inner peripheral part a, and a part located on the outer peripheral side is referred to as an outer peripheral part b.

  The dust-proof glass 51 is formed in a rectangular plate shape long in the main scanning direction, and is adhered to the back surface of the seal member 52 as shown in FIG. The dustproof glass 51 is formed in a size larger than the inner peripheral end 52a of the seal member 52 and smaller than the outer peripheral end 52b. That is, the dust-proof glass 51 is formed in a size corresponding to the inner peripheral side portion a of the seal member 52, and the outer peripheral side portion b of the seal member 52 protrudes from the outer peripheral frame of the dust-proof glass 51. . As shown in FIGS. 4 and 5, the dustproof glass 51 is sandwiched between the stay 50 and a part of the housing 41 via a seal member 52.

  As shown in FIGS. 4 and 5, the casing 41 has a portion corresponding to the back surface 50 a of the window portion H <b> 2 of the stay 50 formed in an uneven shape, and an inner circumference corresponding to the inner circumference side portion a of the seal member 52. It has the side pressing surface 41a and the outer peripheral side pressing surface 41b corresponding to the outer peripheral side part b. Among these, the inner peripheral side pressing surface 41 a is a surface that compresses the inner peripheral side portion “a” of the seal member 52 by pressing the peripheral edge portion of the back surface 51 a of the dust-proof glass 51. On the other hand, the outer peripheral side pressing surface 41 b is a surface that directly compresses the outer peripheral side portion b protruding from the dust-proof glass 51 in the seal member 52.

  A step portion 41 c is formed between the inner peripheral side pressing surface 41 a and the outer peripheral side pressing surface 41 b of the housing 41. The step 41c is formed such that the outer peripheral pressing surface 41b protrudes toward the stay 50 with respect to the inner peripheral pressing surface 41a, and further, the outer peripheral pressing surface 41b is wide and the inner peripheral pressing surface 41a. A so-called tapered in-row portion 41d having a narrow side is formed.

  Here, when the step of the step portion 41c is F, the step F is a distance from the inner peripheral side pressing surface 41a to the outer peripheral side pressing surface 41b. In the present embodiment, the step F is set to be larger than the thickness t of the dust-proof glass 51 and preferably smaller than twice the thickness t of the dust-proof glass 51.

  Here, the dust-proof device 60 of the light emission unit of the present embodiment includes the stay 50, the dust-proof glass 51, the seal member 52, and a part of the housing 41 (the inner peripheral pressing surface 41a and the outer peripheral pressing surface 41b). It is constituted by.

  It continues and demonstrates the effect | action and effect of the dustproof apparatus 60 of the light emission unit of the above-mentioned structure.

  The exposure apparatus 22 shown in FIG. 2 including the dustproof device 60 of the light emission unit is assembled as follows.

  As shown in FIG. 3, a frame-like seal member 52 is attached to the peripheral portion 50b of the back surface 50a of the stay 50 fixed to the frame (not shown) of the image forming apparatus 10 (see FIG. 1). Further, a dustproof glass 51 is attached to the back surface of the seal member 52.

  In this state, as shown in FIG. 6A, the light emitting unit 40 is fixed (positioned) at a predetermined position of the frame while being brought close to the back surface 51a side of the dust-proof glass 51. 6A and 6B, the stay 50 and the seal member 52 are not shown.

  At the time of positioning the light emitting unit 40, the dust-proof glass 51 is urged by the seal member 52 so as to be guided to the in-row portion 41d of the stepped portion 41c of the housing 41, and the inner peripheral side pressing surface (positioning surface). It adheres following 41a. Thus, the dust-proof glass 51 at the time of assembly is equalized to the in-row part 41d, so that the assembly work is facilitated. Further, the dust-proof glass 51 is urged by the seal member 52 and positioned with high accuracy of the inclination angle θ, although it is separate from the light emitting unit 40. The inclination angle θ is used to irradiate the target position of the photosensitive drum 20 with light by providing a step in the vertical direction between the light incident from the back surface 51a of the dust-proof glass 51 and the light emitted from the front surface. It's a thing. For this reason, when the accuracy of the inclination angle θ is low, the light applied to the photosensitive drum 20 is shifted from the target position, and therefore, a good electrostatic latent image may not be formed.

  As shown in FIG. 5, when the light emission unit 40 is fixed (positioned) to a predetermined position of the frame with respect to the stay 50, the seal member 52 is disposed between the stay 50 and the dust-proof glass 51 and between the stay 50 and the stay 50. It is sandwiched between the casing 41 and compressed.

  At this time, of the lower part 52B of the seal member 52, the inner peripheral part a is compressed by the peripheral edge of the dust-proof glass 51 pressed by the inner peripheral pressing surface 41a of the housing 41. And the dust-proof glass 51 is closely_contact | adhered to the inner peripheral side press surface 41a by the reaction force (restoring force) of the inner peripheral side part a of the compressed seal member 52, and ensures the attachment position accuracy with high inclination angle (theta). be able to.

  On the other hand, the outer peripheral portion b of the lower portion 52B of the seal member 52 is directly compressed by the outer peripheral pressing surface 41b of the housing 41.

Here, as described above, between the step F and the thickness t of the dust-proof glass,
t <F <2t
Is established.

  Based on the first half portion (t <F) of this inequality, the upper portion 52A of the seal member 52, which had a thickness Tb before compression, is a portion on the outer peripheral side than the compression width (compression amount) of the inner peripheral portion a. The compression width (compression amount) of b is larger. For this reason, in the seal member 52 after compression, the reaction force (restoring force) of the outer peripheral portion b having a large compression width is larger than the reaction force (restoring force) of the inner peripheral portion a having a small compression width. . Accordingly, the dust-proof glass 51 can be brought into contact with high attachment position accuracy (inclination angle θ) while preventing the contact pressure of the dust-proof glass 51 from being excessively increased with respect to the inner circumferential side pressing surface 41a. On the other hand, the clamping pressure of the outer peripheral side portion b can be increased between the outer peripheral side pressing surface 41b and the surface of the stay 50 facing the outer peripheral side pressing surface 41b, thereby improving adhesion and dust resistance.

  On the other hand, the latter half of the above inequality (F <2t) prevents a shortage of the contact pressure of the dust-proof glass 51 against the inner peripheral pressing surface 41a due to the step F becoming too large.

  In the above, the lower part 52B of the seal member 52 has been described, but the same applies to the upper part 52A of the seal member 52, the left part, and the right part.

  a: inner peripheral side portion of sealing member, b: outer peripheral side portion of sealing member, F: step, H1: opening, H2: window, L: light, P: sheet, t: dustproof glass (transparent member) Thickness, 10: Image forming apparatus, 20: Photosensitive drum (photoconductor), 40: Light emission unit, 41: Housing, 41a: Inner peripheral side pressing surface, 41b: Outer peripheral side pressing surface, 41c: Stepped part, 41d DESCRIPTION OF SYMBOLS In-row part, 50 ... Stay (attachment member), 50b ... Peripheral part, 51 ... Dust-proof glass (transparent member), 52 ... Seal member (elastic member), 60 ... Dust-proof device of a light emission unit.

Claims (5)

A light emitting unit for emitting light from the opening of the housing;
A mounting member having a window corresponding to the opening;
A seal member provided over the peripheral edge of the window,
A transparent member that is formed smaller than the seal member and is sandwiched between the housing and the mounting member via the seal member to close the opening,
The housing includes an inner peripheral pressing surface that compresses an inner peripheral side portion of the seal member by pressing a peripheral portion of the transparent member, and an outer peripheral side portion that protrudes from the transparent member of the seal member. An outer peripheral side pressing surface that compresses with a larger compression width than the inner peripheral side part,
A dustproof device for a light emitting unit. A step is formed between the inner peripheral pressing surface and the outer peripheral pressing surface,
The step of the step portion is larger than the thickness of the transparent member,
The dustproof device for a light emitting unit according to claim 1. An in-row part to which the transparent member is engaged is formed in the step part.
The dustproof device for a light emitting unit according to claim 2. The light emission unit includes a rotating polygon mirror that is housed in the housing and that is rotated by the driving unit and deflects light from the light source to transmit the transparent member.
The dustproof device for a light emitting unit according to any one of claims 1 to 3. A photoreceptor,
A light-proof unit for a light-emitting unit according to any one of claims 1 to 4, as a light-emitting unit that irradiates light to the charged photoreceptor to form an electrostatic latent image.
An image forming apparatus.

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