JP3949668B2 - Photostatic device and image forming apparatus using the same - Google Patents

Description

  The present invention relates to a photostatic discharger that removes residual charges on a photoreceptor by light irradiation in an electrophotographic image forming process, and an image forming apparatus such as a copying machine including the same.

  An electrophotographic image forming apparatus is an apparatus that forms an image by each process of charging, exposure, development, transfer, and fixing. For example, in the case of a copying machine, the above processes are performed as follows.

  First, an electrostatic latent image is formed by exposing reflected light of an original image through an optical system on the surface of a photoconductor (photosensitive drum) given a uniform charge by a charger charger. A toner (developer) is electrostatically attached to the image and developed to form a toner image on the photoreceptor. Next, the toner image is transferred onto the recording paper by applying static electricity having a polarity opposite to that of the toner image to the transfer body, and the transferred toner is fixed by heating and pressurizing, and an image corresponding to the original image is formed on the recording paper. Immobilize.

  Many functional elements are added to the basic configuration of the copying machine configured as described above for the purpose of improving the image quality and the efficiency of forming a copied image. For example, this corresponds to an optical static elimination device that neutralizes the charge on the photosensitive member by light irradiation. Examples of the light neutralizing device include an eraser that erases a defective latent image in a non-image area on a photoconductor before development processing, a pre-transfer neutralization lamp (PTL) that optically lowers the potential on the photoconductor before transfer processing, Examples thereof include a static elimination lamp (QL) that removes residual charges on the photoconductor after the cleaning process.

  A discharge tube such as a fluorescent tube is used as an illumination light source of such a light neutralizing device. As shown in FIG. 15, an LED array 500 in which a large number of LED chips 502 are arranged on a substrate 501 is used. In particular, in recent years, there has been a demand for products that are smaller and less expensive.

  As shown in FIG. 16, the LED array 500 has a high illuminance that is substantially uniform with respect to the surface of the photosensitive drum 1 that is a surface to be illuminated by closely arranging LED chips (LED lamps) 502. Can be obtained.

  However, in this configuration, since the number of LED chips 502 used is large, it is difficult to achieve a sufficient cost reduction in terms of cost. Further, when the number of LED chips 502 used is reduced in order to achieve cost reduction, the spacing between the LED chips 502 increases, and the illuminance distribution of the photosensitive drum 1 is uneven, thereby obtaining uniform illuminance. I can't.

  As a technique for solving such a problem, a columnar member made of a translucent material, a light irradiation surface provided on a side surface portion along the longitudinal direction, and a cutting process or roughening provided on a surface opposite to the light irradiation surface. There has been disclosed an illumination device that includes a light guide having a light diffusing portion by surface processing and that has a light source provided at an end of the light guide (see, for example, Patent Document 1).

Moreover, it is an apparatus having a structure in which light from an LED light source is incident from an end portion of a light guide formed of a rod-shaped light-transmitting material, and light emission for emitting an incident light beam to a side surface portion along the rod-shaped longitudinal direction. An illuminating device including a light guide body having a surface and a sawtooth region for reflecting and diffusing light incident on the side surface portion facing the light emitting surface is disclosed (for example, , See Patent Document 2.)
JP 08-043333 A JP 10-1333026 A

  However, according to the configuration described in each of the above-mentioned patent documents, among the areas where light is irradiated from the light guide to the photosensitive drum, the irradiation light amount is large in the area close to the light source, and the irradiation is performed in the area far from the light source. The problem of low light intensity remains. If the distribution of the irradiation light amount varies in the longitudinal direction of such a photosensitive drum, image unevenness or the like occurs and a good image cannot be obtained.

  The present invention has been made in view of such circumstances, and in an electrophotographic image forming apparatus, the light amount distribution of irradiation light irradiated on a photoconductor to remove the charge on the photoconductor is made more uniform. It is an object of the present invention to provide an optical static elimination device capable of performing the above-mentioned and an image forming apparatus including the optical static elimination device having such characteristics.

An optical static elimination device of the present invention is an optical static elimination device used to neutralize charges on a photoconductor in an electrophotographic image forming apparatus, a light guide disposed opposite to the photoconductor, A light source that emits light to the light incident surface of the light guide, and the light guide is formed with two diffuse reflection surfaces that reflect the light from the light source toward the photoconductor, Furthermore, the first light guide body portion and the second light guide body portion on which two diffuse reflection surfaces are formed are arranged adjacent to each other with a predetermined interval on the upstream side and the downstream side in the rotation direction of the photosensitive member. A reflection surface for bending the optical path of the light guide is formed between the two diffusion reflection surfaces.

  According to the light static eliminator of the present invention, since the two light-reflecting surfaces whose light traveling directions are opposite to each other are formed on the light guide, the region where the amount of reflected light from one of the light-diffusing surfaces is small It is possible to compensate with the reflected light due to the diffuse reflection of the light, and the total light amount distribution in the light irradiation region of the photoconductor can be made uniform.

  In the light static eliminator of the present invention, the two diffuse reflection surfaces formed on the light guide are respectively the height of the light guide relative to the light exit surface to the photosensitive member, and the width of the reflection surface (photosensitive member). The length in a direction perpendicular to the longitudinal direction of the light source may vary according to the distance from the light source. By adopting such a configuration, it is possible to further uniformize the light amount distribution of the irradiation light irradiated on the photosensitive member.

  In the above-described optical static elimination device of the present invention, the width of the light guide may be constant, and only the width of the diffuse reflection surface may be changed. If such a structure is employ | adopted, the above-mentioned effect can be achieved, without impairing the bending rigidity of a light guide.

  In the above-described light static elimination device of the present invention, when a reflection surface (total reflection surface) is formed at the end of the light guide so that incident light is reflected at the end, the light utilization efficiency is improved and the end The decrease in the amount of light in the vicinity can be improved.

  The image forming apparatus of the present invention is characterized by including the light neutralizing device having the above-described characteristics.

According to the light neutralizing device of the present invention, the light guide device has two light guides formed with a diffuse reflection surface for reflecting light from the light source toward the photoconductor, and the two light guides are light from the light source. Are arranged so that their traveling directions are opposite to each other, the total light amount distribution can be made uniform. Furthermore, since the two light-reflecting surfaces whose light traveling directions are opposite to each other are formed on the light guide, the total light amount distribution in the light irradiation region of the photosensitive member can be made uniform.

  According to the image forming apparatus of the present invention, since the light neutralizing device having the above-described characteristics is provided, a good image can be obtained.

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

<Embodiment 1>
-Image forming device-
FIG. 1 is a diagram illustrating an example of an image forming apparatus according to the present invention.

  The image forming apparatus 100 in this example is a digital multi-function peripheral capable of facsimile operation, copy operation, and printer operation, and includes an image reading unit 101, an image forming unit 102, a paper feeding unit 103, and a post-processing device 104. ing.

  The image reading unit 101 is provided as an image input device of the image forming apparatus 100 for reading an image such as a document. In addition to the document placing table 105 made of transparent glass, the image reading unit 101 is a double-sided automatic document feeder (hereinafter, referred to as a document feeder). RADF) 106 and an optical system unit 110.

  The image reading unit 101 sequentially reads images of the original document one by one from the original document placed on the document placement table 105. The RADF 106 conveys originals set on a predetermined original tray one by one to the original placing table 105, and after the image is read by the optical system unit 110, it is carried out to a predetermined extraction position.

  The optical system unit 110 is configured as a document image reading unit that reads an image of a document conveyed to the document placing table 105 in predetermined units in the scanning line direction. The optical system unit 110 includes a first mirror base 111, a second mirror base 112, an optical lens 117, and a photoelectric conversion element (hereinafter referred to as a CCD) 118.

  The first mirror base 111 includes a lamp reflector assembly 113 for irradiating light, and a first reflection mirror 114 for guiding reflected light from the document to a second mirror base 112 described later, and a document placement table. The original is irradiated with light while moving at a constant speed V from left to right in FIG.

  The second mirror base 112 includes a second reflection mirror 115 and a third reflection mirror 116 that guide the light from the first mirror base 111 in the direction of the optical lens 117 and the CCD 118, and the first mirror Following the operation of the base 111, it moves at a speed of V / 2.

  The optical lens 117 focuses the reflected light from the second mirror base 112 on the CCD 118. The CCD 118 converts the light imaged by the optical lens 117 into an electrical signal. The analog electrical signal obtained by the CCD 118 is converted into image data of a digital signal, subjected to various image processing, and then transferred to the image forming unit 102 through a buffer memory or the like as appropriate.

  The image forming unit 102 includes an image forming unit 120 and an exposure unit 121. The exposure unit 121 exposes the photosensitive drum 1 in accordance with image data read from the buffer memory or image data transferred from an external device. Although not shown, the exposure unit 121 is a semiconductor laser light source that irradiates laser light, a polygon mirror that polarizes the laser light at an equiangular velocity, and further polarizes light from the polygon mirror so as to be constant speed on the photosensitive drum 1. An f-θ lens to be moved is provided.

  As shown in FIG. 2, the image forming unit 120 includes a photosensitive drum 1 that carries an electrostatic latent image. In the periphery of the photosensitive drum 1, toner is supplied to the electrostatic latent image formed on the surface of the photosensitive drum 1 by the charging device 2 that charges the surface of the photosensitive drum 1 to a predetermined potential and the exposure unit 121. The developing device 3 for visualizing, the transfer device 4 for transferring the toner image on the surface of the photosensitive drum 1 to a sheet, the cleaning device 5 for cleaning the surface of the photosensitive drum 1, and the residual charge on the photosensitive drum 1 are neutralized. The light neutralizing device 10 is arranged in this order, and charging, exposure, development, transfer, cleaning, and neutralization processes are performed on the surface of the photosensitive drum 1. Note that a sheet on which a predetermined image forming process has been performed in the image forming unit 120 is heated and fixed by a fixing device 107 provided downstream of the image forming unit 120, and is discharged from the paper discharge roller 137. Paper.

  On the downstream side of the image forming unit 120 and the fixing device 107, a switchback conveyance path 136 that reverses the sheet for forming images on both sides of the sheet and an elevating tray 141 are provided, and the sheet on which the image is fixed is provided. A post-processing device 104 that performs stapling processing or the like is disposed.

  The paper feed unit 103 is disposed below the image forming unit 120, and includes a multi-stage paper feed unit including a manual feed tray 134, a duplex unit 135, paper cassettes 131, 132, and 133, and a storage unit for these sheets ( 131 to 134) are provided with conveying means for conveying the sheet to the image forming unit 120. Note that the duplex unit 135 communicates with the switchback conveyance path 136 and is used when image formation is performed on both sides of the sheet.

-Optical neutralization device-
Next, the optical static elimination device 10 will be described.

  As shown in FIGS. 3 to 5, the light neutralizing device 10 includes an LED lamp 11 that is a point light source and a light guide (made of a light-transmitting material) 12.

  The light guide 12 is mounted on the process cartridge 20 as shown in FIGS. The process cartridge 20 is detachable by sliding on a cartridge guide member 23 attached to the front frame 21 and the rear frame 22 of the main body of the image forming apparatus 100.

  The LED lamp 11 is disposed to face the end portion 20a on the front end side in the mounting direction indicated by the arrow M of the process cartridge 20 that is a non-image forming area of the photosensitive drum 1.

  As shown in FIGS. 3 and 4, the light guide 12 is a band-shaped member extending in a direction parallel to the photosensitive drum 1, and a surface facing the photosensitive drum 1 is a light emitting surface 12 b. One end surface (tip surface) in the longitudinal direction of the light guide body 12 is a light incident surface 12a, and the LED lamp 11 faces the light incident surface 12a.

  The light guide body 12 is formed with a light guide path portion X1 that becomes a light guide path of light from the LED lamp 11, and a reflection portion X2 and a reflection portion X3 that constitute a charge removal region.

  The reflection part X2 is processed so that the light emission surface 12b and the back surface 12d thereof are parallel to each other. The reflecting portion X3 is processed so that the back surface 12d is inclined with respect to the light emitting surface 12b, and the back surface 12d approaches the light emitting surface 12b toward the rear end surface 12e of the light guide 12.

  The back surface 12d of the light guide 12 is formed with a diffuse reflection surface (prism surface) 12c that reflects light from the LED lamp 11 toward the photosensitive drum 1 in a region corresponding to the reflection portion X2 and the reflection portion X3. Has been. The height H of the diffuse reflection surface 12c with respect to the light emission surface 12b is constant in the reflection portion X2. In addition, the height H of the diffuse reflection surface 12c in the reflection portion X3 with respect to the light emission surface 12b decreases toward the rear end portion of the reflection portion X3 (the rear end surface 12e of the light guide 12). Further, the width W of the diffuse reflection surface 12c (the length in the direction orthogonal to the axial direction of the photosensitive drum 1) is not constant, and as shown in FIG. 4B, the end of the reflection portion X2 on the light incident side. From the middle of the reflecting portion X2, the width decreases toward the reflecting portion X3, and the width increases toward the rear end portion of the reflecting portion X3 (the rear end surface 12e of the light guide 12).

  As described above, the light guide 12 in this example has the height H (the length in the Y direction) with respect to the light exit surface 12b of the diffuse reflection surface 12c that reflects the light from the LED lamp 11 toward the photosensitive drum 1. However, the width W of the diffuse reflection surface 12c also changes corresponding to the position relative to the LED lamp 11 (position in the X direction). Therefore, the light intensity distribution of the irradiation light to the photosensitive drum 1 can be made uniform over the entire area in the axial direction (longitudinal direction) of the photosensitive drum 1. Therefore, it is possible to obtain a high-quality image without image unevenness.

  Here, the light guide 12 used in the light neutralization device 10 of this example is a surface having a smooth entire surface other than the diffuse reflection surface 12c on which irregularities such as a prism surface are formed. The light guide 12 is formed by molding a transparent material such as an acrylic resin, a polycarbonate resin, a polystyrene resin, a vinyl chloride resin, or glass by an injection molding method or an extrusion method, and performing a treatment such as polishing as necessary. Alternatively, the entire surface of the light guide 12 may be a smooth surface, and a white turbid diffusion tape may be attached only to a portion to be the diffuse reflection surface 12c.

  The LED lamp 11 used in the light neutralizing device 10 of this example is manufactured by bonding an LED chip on a metal lead and sealing the portion in a lens shape with a transparent resin. Near the light incident surface 12a. Examples of the LED lamp 11 include an ultra-bright LED lamp (Sharp, product number: GL5ZJ43) having a wavelength of 618 nm and an experimental resistance value of 200Ω.

  In this example, a reflective surface (total reflection surface) by aluminum vapor deposition or the like may be formed on the rear end surface 12e of the light guide 12 similarly to the light guide 312 shown in FIG.

<Embodiment 2>
Another example of the optical static eliminating device of the present invention is shown in FIGS.

  The light neutralizing device 210 in this example includes two light guides 212 and 212 disposed to face the photosensitive drum 1 (see FIG. 3), and light incident surfaces 212a and 212a of the light guides 212 and 212, respectively. LED lamps 11 and 11 for irradiating light, and these two light guides 212 and 212 are arranged so that the traveling directions of light from the LED lamps 11 and 11 are opposite to each other. There is a feature in that. The two light guides 212 and 212 have the same shape and structure.

  Most of the back surfaces 212d of the light guides 212 and 212 are inclined surfaces, and the diffuse reflection surfaces (prism surfaces) that reflect the light from the LED lamps 11 toward the photosensitive drum 1 on the inclined surfaces. ) 212c and 212c are formed.

  The diffuse reflection surfaces 212c and 212c of the light guides 212 and 212 have a height H with respect to the light exit surface 212b and a width W of the diffusion reflection surfaces 212c and 212c (in a direction orthogonal to the axial direction of the photosensitive drum 1). The length) is formed so as to decrease at a constant ratio toward the rear end surfaces 212e and 212e of the light guides 212 and 212 according to the distance from the LED light sources 11, respectively.

  According to the light neutralizing device 210 of this example, the two light guides 212 and 212 are arranged in combination so that the light traveling directions are opposite to each other. Since the small area can be supplemented by the light emitted from the other light guide 212, the total light quantity distribution in the axial direction of the photosensitive drum 1 can be made uniform (see Example 3 in FIG. 13).

  In addition, the material and manufacturing method of the light guide 212 used in the light neutralizing device 210 of this example are the same as in the above-described <Example 1>.

  Moreover, in the light static elimination apparatus 210 of this example, the reflective surface (total reflection surface) by aluminum vapor deposition etc. is formed in the rear-end surface 212e of the light guide 212 similarly to the light guide 312 shown in the following FIG. It may be left.

<Embodiment 3>
FIG. 7 shows another example of the optical static eliminating device of the present invention.

  The optical static elimination device 310 of this example is a modification of the optical static elimination device of FIG. 4 and has a structure in which the light guide path portion 312f is folded, and light is incident between the light guide path portion 312f and the diffuse reflection surface 312c. Reflection surfaces (total reflection surfaces) 312g and 312h for bending light incident on the surface 312a (irradiation light of the LED lamp 11) and guiding it to the diffuse reflection surface 312c are formed, and after the light guide 312. A feature is that a reflection surface (total reflection surface) 312r is formed on the end surface 312e by vapor deposition of aluminum or the like. The height H of the diffuse reflection surface 312c of the light guide 312c in this example with respect to the light exit surface 312b and the width of the diffuse reflection surface 312c are the same as those of the light guide 12 shown in FIG.

  According to the optical static elimination device 310 of this example, the optical path length of the static elimination region can be increased without increasing the length of the light guide 312 in the optical axis direction. As a result, the image forming apparatus can be reduced in size. Further, by reflecting light toward the light guide 312 by the reflecting surface 312r formed on the rear end surface 312e of the light guide 312, the light utilization rate is improved and the amount of light near the end of the light guide 312 is increased. Decrease can be improved.

  In addition, the material and manufacturing method of the light guide 312 used in the light neutralizing device 310 of this example are the same as in the above-described <Example 1>.

  Here, in the example of FIG. 7, the light guide path portion 312f is folded back. However, the structure is not limited thereto, and the light guide path portion 312f extends along the direction intersecting the diffuse reflection surface 312c ( A substantially L-shaped structure) may be used.

<Embodiment 4>
Another example of the optical static eliminating device of the present invention is shown in FIGS.

  The light static elimination device 410 of this example is provided with a first reflection part R1 and a second reflection part R2 with the light guide 412 folded back, and the first reflection part R1 and the second reflection part R2 respectively. Between the point where the diffuse reflection surfaces (prism surfaces) 412c and 422c that reflect the light from the LED lamp 11 toward the photosensitive drum 1 (see FIG. 3) are formed, and between the two diffuse reflection surfaces 412c and 422c, It is characterized in that reflection surfaces (total reflection surfaces) 412g and 412f for guiding the light that has passed through the first reflection portion R1 to the second reflection portion R2 by bending the optical path are formed.

  The diffuse reflection surfaces 412c and 422c have heights H1 and H2 with respect to the light exit surface 412b of the light guide 412 and widths W1 and W2 of the diffuse reflection surfaces 412c and 422c (in the axial direction of the photosensitive drum 1). The length in the direction orthogonal to each other is formed so as to decrease at a constant ratio toward the rear end surface 412e of the light guide 412 according to the distance from each LED light source 11. Further, the two diffuse reflection surfaces 412c and 422c are formed in such an arrangement that the light traveling directions are opposite to each other.

  In addition, in the light guide 412 of FIG. 8, the back surface 412d of the first reflecting portion R1 and the back surface 422d of the second reflecting portion R2 are inclined, and the light emitting surface of the terminal portion of the first reflecting portion R1 The height with respect to 412b is substantially equal to the height with respect to the light emitting surface 412b of the front end portion of the second reflecting portion R2.

  According to the light neutralizing device 410 of this example, the region where the amount of reflected light by the one diffuse reflection surface 412c (or the diffuse reflection surface 422c) formed on the light guide 412 is small is changed to the other diffuse reflection surface 422c (or Since the light reflected by the diffuse reflection surface 412c) can be supplemented, the total light quantity distribution in the axial direction of the photosensitive drum 1 can be made uniform.

  In addition, the material and manufacturing method of the light guide 412 used in the light static elimination device 410 of this example are the same as those in the above-described <Example 1>.

  Further, in the light static elimination device 410 of this example, a reflection surface (total reflection surface) by aluminum vapor deposition or the like is formed on the rear end surface 412e of the light guide 412 in the same manner as the light guide 312 shown in FIG. Also good.

  Examples of the present invention will be described below together with comparative examples.

<Example 1>
3 and 4, the thickness of the light guide 12 is 3 mm, the length of the diffuse reflection surface 12 c is 300 mm, and the height of the diffuse reflection surface 12 c relative to the light exit surface 12 b (light guide height). ) H is constant from the front end (X = 0) to X = 125 mm (H = 8 mm) of the diffuse reflection surface 12c as shown in FIG. 10A, and the diffuse reflection surface 12c from the position of X = 125 mm. The distance up to the rear end (X = 300 mm) was changed (decreased) at a constant ratio in the range of 8 mm to 4.2 mm. Further, as shown in FIG. 10B, the width W of the diffuse reflection surface 12c is constant within a range of 4.5 mm to 3 mm from the front end portion (X = 0) of the diffuse reflection surface 12c to X = 50 mm. The ratio between the position of X = 50 mm and the rear end (X = 300 mm) from the position of X = 50 mm is changed (increased) in the pattern shown in the figure in the range of 3 mm to 4 mm. It was.

  Using the light guide 12 having the diffuse reflection surface 12c described above, the light intensity of the emitted light was measured when the light incident surface 12a of the light guide 12 was irradiated from the LED lamp 11 in the form shown in FIG. . The measurement results are shown in FIG. FIG. 11 shows the normalized light intensity.

<Comparative Example 1>
In Example 1, the light guide is the same as Example 1 except that the width of the diffuse reflection surface of the light guide is constant (see FIG. 14, width W ′ of the diffuse reflection surface 12c ′: 3.0 mm). ) Was used to measure the light intensity of the emitted light. The measurement results are shown in FIG.

  As is clear from the results of FIG. 11, it is understood that the uniformity of the light intensity distribution is improved by changing the width of the diffuse reflection surface of the light guide according to the distance from the LED lamp 11.

<Example 2>
In the light static elimination device 310 shown in FIG. 7, the thickness of the light guide 312 is 3 mm, the length of the diffuse reflection surface 312c is 300 mm, and the height (light guide height) H of the diffuse reflection surface 312c with respect to the light exit surface 312b is set. As shown in FIG. 12A, the front end portion (X = 0) of the diffuse reflection surface 312c is 8 mm, the rear end portion (X = 300 mm) of the diffuse reflection surface 312c is 2.0 mm, and the diffuse reflection surface 312c. The front end portion and the rear end portion were changed (decreased) at a constant ratio. Further, as shown in FIG. 12B, the width W of the diffuse reflection surface 312c is constant at 3.0 mm from the front end portion (X = 0) of the diffuse reflection surface 312c to X = 50 mm, and X = The distance from the position of 50 mm to the rear end portion (X = 300 mm) of the diffuse reflection surface 312c was changed (increased) at a constant ratio in the range of 3.0 mm to 4.5 mm.

  Using the light guide 312 having the diffuse reflection surface 312c described above, the light intensity of the emitted light when the light incident surface 312a of the light guide 312 was irradiated from the LED lamp 11 in the form shown in FIG. 3 was measured. . The measurement results are shown in FIG. FIG. 13 shows the normalized light intensity.

<Example 3>
6, the thickness of each light guide 212 is 3 mm, the length of the diffuse reflection surface 212c is 300 mm, and the height of the diffuse reflection surface 212c relative to the light exit surface 212b of each light guide 212 ( As shown in FIG. 12A, the light guide body height H is set to 8 mm at the front end portion (X = 0) of the diffuse reflection surface 212c, and the rear end portion (X = 300 mm) at the diffuse reflection surface 212c is set to 2. The distance between the front end portion and the rear end portion of the diffuse reflection surface 212c was changed (decreased) at a constant ratio. Furthermore, as shown in FIG. 12B, the width W of the diffuse reflection surface 212c is constant at 3.0 mm from the front end portion (X = 0) of the diffuse reflection surface 212c to X = 50 mm, and X = The distance from the position of 50 mm to the rear end (X = 300 mm) of the diffuse reflection surface 212c was changed (increased) at a constant ratio in the range of 3.0 mm to 4.5 mm.

  Using the light guide 212 having the diffuse reflection surface 212c described above, the light intensity of the emitted light was measured when the light incident surface 212a of the light guide 212 was irradiated from the LED lamp 11 in the form shown in FIG. . The measurement results are shown in FIG. FIG. 13 shows the normalized light intensity.

<Comparative example 2>
In Example 2, except that the width of the diffuse reflection surface of the light guide is constant, the light emitted from the light guide is the same as in Example 2 (the width of the diffuse reflection surface: 3.0 mm). The strength was measured. The measurement results are shown in FIG.

  As is clear from the results of FIG. 13, it is understood that the uniformity of the light intensity distribution is improved by changing the width of the diffuse reflection surface of the light guide according to the distance from the LED lamp 11. In addition, it can be seen from the results of Example 3 that the total light quantity distribution in the axial direction of the photosensitive drum 1 can be made uniform by arranging the two light guides 312 and 312 in a reverse combination.

  The present invention relates to an optical charge eliminating device that removes residual charges on a photoconductor by light irradiation in an electrophotographic image forming process, and an image forming apparatus such as a copying machine equipped with the photostatic discharge device. In addition, it can be effectively used to make the light quantity distribution of the irradiation light irradiated to the photosensitive member uniform.

1 is a diagram illustrating a configuration of an embodiment of an image forming apparatus of the present invention. It is a figure which shows the structure of the image forming unit used for the image forming apparatus of FIG. It is a perspective view which shows the principal part structure of embodiment of the optical static elimination apparatus of this invention. It is a figure which writes and shows the side view (A) and top view (B) of the optical static elimination apparatus of FIG. It is a figure which shows the state which mounted | wore the image forming apparatus with the optical static elimination apparatus of FIG. It is a figure which writes and shows both the side view (A) and top view (B) which show the other example of the optical static elimination apparatus of this invention. It is a side view which shows another example of the optical static elimination apparatus of this invention. It is a figure which writes and shows both the side view (A) and top view (B) which show another example of the optical static elimination apparatus of this invention. It is the DD arrow line view of FIG. It is explanatory drawing of Example 1 of this invention. It is a graph which shows the result of having measured the light intensity in Example 1 of this invention. It is explanatory drawing of Example 2, 3 of this invention. It is a graph which shows the result of having measured the light intensity in Example 2, 3 of this invention. It is a top view which shows the structure of the light guide used in the comparative example 1 of this invention. It is a perspective view which shows the structure of the LED array used for the conventional optical static elimination apparatus. It is a side view which shows the structure of the conventional optical static elimination apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charging device 3 Developing device 4 Transfer device 5 Cleaning device 10 Light neutralization device 11 LED lamp 12 Light guide 12a Light incident surface 12b of light guide 12b Light output surface of light guide 12c Diffuse reflection surface 12d Light guide Back surface of body 12e Rear end surface of light guide 20 Process cartridge 21 Front frame of main body of image forming apparatus 22 Rear frame of main body of image forming apparatus 23 Cartridge guide member 100 Image forming apparatus 101 Image reading unit 110 Optical system unit 111 First mirror Base 112 Second mirror base 113 Lamp reflector assembly 114 First reflecting mirror 115 Second reflecting mirror 116 Third reflecting mirror 117 Optical lens 118 CCD
DESCRIPTION OF SYMBOLS 102 Image formation part 120 Image formation unit 121 Exposure unit 103 Paper feed part 131,132,133 Paper cassette 134 Manual feed tray 135 Duplex unit 136 Switchback conveyance path 137 Paper discharge roller 104 Post-processing device 141 Lifting tray 105 Document placement stand 106 Both sides Automatic document feeder (RADF)
107 Fixing device

Claims (5)

An optical static eliminator used to neutralize charges on a photoconductor in an electrophotographic image forming apparatus, a light guide disposed opposite to the photoconductor, and a light incident surface of the light guide A light source for irradiating light, and the light guide body is formed with two diffuse reflection surfaces for reflecting light from the light source toward the photoconductor, and further, the two diffuse reflection surfaces are The formed first light guide body part and second light guide body part are arranged adjacent to each other at a predetermined interval on the upstream side and the downstream side in the rotation direction of the photoreceptor, and between the two diffuse reflection surfaces, optical charge removing device, characterized in that the reflecting surface for bending the optical path of the light guide are formed. Each of the diffuse reflection surfaces is characterized in that the height of the light guide relative to the light exit surface to the photoconductor and the width of the reflection surface change according to the distance from the light source. The optical static eliminating device according to claim 1 . 3. The light neutralizing device according to claim 1, wherein the width of the light guide is constant, and only the width of the diffuse reflection surface is changed . The light neutralizing apparatus according to claim 1, wherein a reflection surface is formed at an end of the light guide . An image forming apparatus comprising the light static eliminator according to claim 1.

Images