JP2010008725A - Charge removing device and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charge removing device which is capable of uniformly removing the charge of the circumferential surface of a photoreceptor in the center axis direction of the photoreceptor, while reducing the size, with a simple configuration and to provide a process cartridge. <P>SOLUTION: In the charge removing device 10, a reflecting member 16 is arranged to face the circumferential surface of a photoreceptive drum 7 and a light source 22 is arranged on the side of the photoreceptive drum 7 in its center axis direction (width direction). In the reflecting member 16, a recessed portion 16A opened on the side of the photoreceptive drum 7 is formed. The recessed portion 16A is provided with a plurality of projecting portions 17 having a reflecting surface 18 and projecting toward the side of the photoreceptive drum 7. Since an opposing interval between the plurality of projecting portions 17 and the photoreceptive drum 7 is smaller as it gets away from the light source 22, the reflecting surfaces 18 of the projecting portions 17 at places which are away from the light source 22 and difficult to sufficiently obtain light can surely reflect the light obtained from the light source 22 to the photoreceptive drum 7. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a static eliminator and a process cartridge for removing charges on the outer peripheral surface of a photoreceptor in an image forming apparatus.

  In an electrophotographic image forming apparatus including a photoreceptor, generally, an electrostatic latent image formed on the outer peripheral surface of a charged photoreceptor is developed with a developer to form a developer image. Is transferred to a recording medium to form an image. Then, every time the transfer of the developer image onto the recording medium is completed, it is necessary to remove (static charge) the charge remaining on the outer peripheral surface of the photoreceptor in preparation for the next image formation.

Therefore, as an apparatus for removing charges, for example, the erasing means described in Patent Document 1 includes a parabolic reflector. The parabolic reflector is disposed so as to face the outer peripheral surface of the photosensitive drum, and is entirely curved so as to draw a parabola as it proceeds along the direction of the central axis of the photosensitive drum. In relation to this parabolic reflector, a light source is disposed at the focal position of the parabolic reflector, and the light emitted from the light source is reflected by the parabolic reflector and is reflected to the outer peripheral surface of the photosensitive drum. Irradiated over the entire range in the axial direction. Thereby, the outer peripheral surface of the photosensitive drum is exposed, and the electric charge remaining on the outer peripheral surface of the photosensitive drum is removed.
JP-A-3-289668

The erase means described in Patent Document 1 removes the charge on the outer peripheral surface of the photosensitive drum by reflecting the light from the light source with a parabolic reflector and irradiating the outer peripheral surface of the photosensitive drum. It is only necessary to have a parabolic reflector, and the configuration is relatively simple.
However, since the entire parabolic reflector is curved and bulky, there is a concern about an increase in the size of an apparatus (which is an image forming cartridge and an image forming apparatus in Patent Document 1) in which erase means including a parabolic reflector is arranged. Is done. Therefore, it is desirable to reduce the size of the erasing means. However, it is more desirable that the erasing means can uniformly reduce the charge on the outer peripheral surface of the photosensitive drum in the central axis direction while reducing the size of the erasing means.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a static eliminator and a process cartridge capable of uniformly removing charges on the outer peripheral surface of a photoconductor along the central axis direction of the photoconductor while reducing the size with a simple configuration. It is in.

  In order to achieve the above object, the invention described in claim 1 is a static eliminator for removing electric charges on the outer peripheral surface of a photoconductor, wherein the light source is arranged laterally in the central axis direction of the photoconductor, A reflecting member disposed opposite to the outer peripheral surface of the photosensitive member and reflecting light from the light source toward the photosensitive member; the reflecting member being spaced apart from the photosensitive member so that the photosensitive member side is opened. A concave portion having an open end on the photoconductor side wider than the deepest portion is formed, and the concave portion has a reflecting surface for reflecting light from the light source toward the photoconductor. The plurality of convex portions projecting toward the photoconductor are provided such that the facing distance from the photoconductor decreases as the distance from the light source increases.

The invention described in claim 2 is characterized in that, in the invention described in claim 1, the reflection surface is larger as the convex part is farther from the light source.
The invention according to claim 3 is characterized in that, in the invention according to claim 1 or 2, the distance between the reflecting surfaces adjacent to each other decreases as the distance from the light source increases.
The invention according to claim 4 is the invention according to claim 2, wherein the plurality of convex portions are arranged along the optical axis direction of the light source, and the reflective surface of each convex portion is: As the distance from the light source is increased, the inclined surface is closer to the photoconductor, and the convex portion further away from the light source has a larger inclination angle with respect to the optical axis direction of the reflecting surface.

The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the recess is substantially U-shaped or substantially V-shaped when viewed from the optical axis direction of the light source. It is characterized by that.
According to a sixth aspect of the present invention, there is provided a process cartridge mounted on the image forming apparatus main body, wherein the process cartridge is disposed to face the outer peripheral surface of the photosensitive member and the photosensitive member. A reflecting member that reflects light from a light source disposed laterally in the direction of the central axis of the body toward the photosensitive member, and the reflecting member is formed from the photosensitive member so that the photosensitive member side is opened. A recess is formed in the direction of separation and the open end on the photoconductor side is wider than the deepest portion, and the recess has a reflecting surface for reflecting light from the light source toward the photoconductor. The plurality of convex portions projecting toward the photosensitive member are provided so that the distance between the opposing portions to the photosensitive member decreases as the distance from the light source increases.

The invention according to claim 7 is characterized in that, in the invention according to claim 6, the reflection surface is larger as the convex part is farther from the light source.
The invention according to claim 8 is characterized in that, in the invention according to claim 6 or 7, the distance between the reflecting surfaces adjacent to each other decreases as the distance from the light source increases.
The invention according to claim 9 is the invention according to claim 7, wherein the plurality of convex portions are arranged along the optical axis direction of the light source, and the reflective surface of each convex portion is: As the distance from the light source is increased, the inclined surface is closer to the photoconductor, and the convex portion further away from the light source has a larger inclination angle with respect to the optical axis direction of the reflecting surface.

  The invention according to claim 10 is the invention according to any one of claims 6 to 9, wherein the recess is substantially U-shaped or substantially V-shaped when viewed from the optical axis direction of the light source. It is characterized by that.

According to the first and sixth aspects of the present invention, the reflecting member is disposed opposite to the outer peripheral surface of the photosensitive member, and the light source is disposed laterally in the central axis direction of the photosensitive member. Light from the light source is reflected toward the photoreceptor by the reflecting member. As a result, the outer peripheral surface of the photoconductor is exposed and the electric charge on the outer peripheral surface of the photoconductor is removed.
The reflecting member is recessed toward the direction away from the photoconductor so that the photoconductor side is opened, and a concave portion having an open end on the photoconductor side wider than the deepest portion is formed. The concave portion has a reflective surface that reflects light from the light source toward the photoconductor, and is provided with a plurality of convex portions that protrude toward the photoconductor. Therefore, in the reflecting member, light from the light source is reflected toward the photosensitive member by the reflecting surfaces of the plurality of convex portions while proceeding through the concave portions. Here, since the photosensitive member side is opened in the concave portion, the reflecting member can reflect the light traveling in the concave portion toward the photosensitive member without leakage. Thereby, the charge on the outer peripheral surface of the photoreceptor can be effectively removed.

  Since the spacing between the plurality of convex portions and the photosensitive member decreases as the distance from the light source increases, the reflective surface of the convex portion at a location where it is difficult to receive light sufficiently away from the light source Can be reliably reflected toward the photoconductor. As a result, it is possible to suppress a decrease in the amount of light reflected from the reflecting member to the photosensitive member as the distance from the light source increases along the central axis direction of the photosensitive member. For this reason, the reflecting member can uniformly reflect the light from the light source to the entire region in the central axis direction of the photosensitive member, so that the charge on the outer peripheral surface of the photosensitive member can be uniformly removed in the central axial direction. Can do.

  As described above, the electric charge on the outer peripheral surface of the photoconductor is reduced with a simple configuration in which a concave portion is formed in the reflective member without bending the entire reflective member and a plurality of convex portions are provided in the concave portion. Can be removed uniformly over the central axis direction. In particular, since the charge on the outer peripheral surface of the photosensitive member can be removed simply by providing a reflecting member in addition to the light source, a member for guiding light from the light source to the photosensitive member need not be provided separately from the reflecting member.

  According to the second and seventh aspects of the present invention, since the convex portion farther from the light source has a larger reflecting surface, the reflective surface of the convex portion located at a location where it is difficult for light to reach sufficiently away from the light source reaches from the light source. The reflected light can be reliably reflected toward the photoconductor. As a result, a sufficient amount of light can be reflected from the portion of the reflecting member away from the light source to the photosensitive member, so that the charge on the outer peripheral surface of the photosensitive member can be more uniformly removed in the central axis direction. Can do.

  According to the third and eighth aspects of the present invention, as the distance from the light source is increased, the interval between the adjacent reflection surfaces is reduced. Therefore, the adjacent reflection surfaces are separated from the light source and the adjacent reflection surfaces reach from the light source. The reflected light can be continuously reflected toward the photoreceptor at a high frequency. As a result, a sufficient amount of light can be reflected from the portion of the reflecting member away from the light source to the photosensitive member, so that the charge on the outer peripheral surface of the photosensitive member can be more uniformly removed in the central axis direction. Can do.

According to the invention described in claims 4 and 9, since the plurality of convex portions are arranged along the optical axis direction of the light source, the reflection surface of these convex portions does not leak light traveling in the optical axis direction. It can be reflected toward the photoreceptor.
Further, since the reflecting surface of each convex portion is inclined so as to be closer to the photosensitive member as it is away from the light source, the light from the light source can be reliably reflected toward the photosensitive member.

  Since the convex portion farther from the light source has a larger inclination angle with respect to the optical axis direction of the reflecting surface, the convex reflecting surface at a location where it is difficult to sufficiently reach the light away from the light source is sensitive to the light reaching the light source. The amount of reflection on the body can be increased. As a result, a sufficient amount of light can be reflected from the portion of the reflecting member away from the light source to the photosensitive member, so that the charge on the outer peripheral surface of the photosensitive member can be more uniformly removed in the central axis direction. Can do.

  According to the fifth and tenth aspects of the present invention, since the concave portion is substantially U-shaped or substantially V-shaped when viewed from the optical axis direction of the light source, the concave portion whose open end on the photoconductor side is wider than the deepest portion. Can be easily formed.

The process cartridge 1 of the present invention will be described below with reference to the drawings.
<Outline of process cartridge>
FIG. 1 is a schematic left sectional view showing an embodiment of a process cartridge according to the present invention. In FIG. 1, arrows (direction arrows) pointing in the up / down / front / back / left / right directions are shown, and the direction arrows are referred to in specifying the direction (the same applies to each of the drawings after FIG. 1). Here, the front side in the paper thickness direction in FIG. 1 is the left side, and the back side in the paper thickness direction in FIG. 1 is the right side. The left-right direction and the width direction are synonymous. The horizontal direction includes the front-rear direction and the left-right direction.

The process cartridge 1 is installed in a main body (image forming apparatus main body) of an electrophotographic image forming apparatus (not shown) such as a laser printer, and functions as a main part of image formation.
The process cartridge 1 includes a housing 2, a developer storage chamber 3, a supply roller 4, a developing roller 5, a layer thickness regulating blade 6, a photosensitive drum 7 as an example of a photosensitive member, a charger 8, and a cleaning. A roller 9 and a static eliminating device 10 are provided.

The housing 2 has a hollow box shape, and in the housing 2, a developer containing chamber 3, a supply roller 4, a developing roller 5, a layer thickness regulating blade 6, a photosensitive drum 7, a charger 8, a cleaning roller 9, and a static elimination device. 10 is arranged.
The developer storage chamber 3 is a space partitioned on the rear side in the housing 2. In the developer storage chamber 3, for example, a positively chargeable non-magnetic one-component toner is stored as an example of the developer.

The supply roller 4 is rotatably supported by the housing 2 at the lower end of the developer storage chamber 3 with the central axis extending in the width direction. Thus, the toner in the developer storage chamber 3 is always deposited on the outer peripheral surface of the supply roller 4 by its own weight.
The developing roller 5 is rotatably supported by the housing 2 with the central axis extending in the width direction, and is pressed against the supply roller 4 from the front.

The layer thickness regulating blade 6 is an elastic body that extends rearward and downward from the wall 2 </ b> A that defines the developer containing chamber 3 in the housing 2 toward the developing roller 5, and the tip (lower end) of the layer thickness regulating blade 6 is the upper outer periphery of the developing roller 5. It is pressed against the surface.
The photosensitive drum 7 has a cylindrical shape, is rotatably supported by the housing 2 with the central axis extending in the width direction, and is pressed against the developing roller 5 from the front. In FIG. 1, the photosensitive drum 7 rotates counterclockwise (see the thick arrow in the figure). The lower outer peripheral surface of the photosensitive drum 7 is exposed downward from the housing 2. The outer peripheral surface (outermost layer) of the photosensitive drum 7 is formed by a positively chargeable photosensitive layer made of, for example, polycarbonate. A communication hole 2 </ b> B for communicating the inside and outside of the housing 2 is formed in a portion corresponding to the upper part of the photosensitive drum 7 on the upper wall of the housing 2.

The charger 8 is, for example, a scorotron type, and is supported by the housing 2 so as to face the outer peripheral surface of the photosensitive drum 7 from above with a gap.
The cleaning roller 9 is rotatably supported by the housing 2 with the central axis extending in the width direction, and is pressed against the photosensitive drum 7 from the front. The outer peripheral surface of the cleaning roller 9 is covered with, for example, a conductive foam material. A predetermined cleaning bias is applied to the cleaning roller 9.

The static eliminator 10 is supported by the housing 2 below the cleaning roller 9 so as to face the outer peripheral surface of the photosensitive drum 7 with a gap from the front. The static eliminator 10 will be described in detail later.
During image formation, toner accumulated on the supply roller 4 in the developer storage chamber 3 enters between the tip of the layer thickness regulating blade 6 and the development roller 5 as the supply roller 4 and the development roller 5 rotate. It becomes a thin layer and is carried on the outer peripheral surface of the developing roller 5.

On the other hand, the outer peripheral surface of the photosensitive drum 7 is uniformly positively charged in the width direction by the charger 8, and then irradiated from the image forming apparatus main body side (not shown) through the communication hole 2B of the housing 2. Exposure with a laser beam (see broken arrow in the figure). As a result, an electrostatic latent image based on the image data is formed on the outer peripheral surface of the photosensitive drum 7.
As the photosensitive drum 7 and the developing roller 5 rotate, the toner carried on the outer peripheral surface of the developing roller 5 is supplied to the electrostatic latent image on the outer peripheral surface of the photosensitive drum 7. As a result, the electrostatic latent image is developed (visualized), and a toner image is carried on the outer peripheral surface of the photosensitive drum 7.

When this toner image is exposed downward from the housing 2 as the photosensitive drum 7 rotates, it is transferred to the recording medium 11. When the toner image transferred to the recording medium 11 is thermally fixed, the image formation is completed.
Here, there are cases where the transfer residual toner remains on the outer peripheral surface of the photosensitive drum 7 after the transfer of the toner image from the photosensitive drum 7 to the recording medium 11. In this case, the untransferred toner is transferred to the outer peripheral surface of the cleaning roller 9 by the cleaning bias described above and captured by the cleaning roller 9 while the photosensitive drum 7 is rotating. At the end of the image formation, a bias reverse to the cleaning bias is applied to the cleaning roller 9, whereby the transfer residual toner captured by the cleaning roller 9 is discharged from the cleaning roller 9 to the photosensitive drum 7. Then, it is collected by the developing roller 5.
<Details of static eliminator>
Next, the static eliminator 10 will be described in detail.

2A is a right side view of the reflecting member of the static eliminator according to the first example, and FIG. 2B is a rear view of the static eliminator according to the first example. FIG.2 (c) is AA arrow sectional drawing of FIG.2 (b). FIG. 3 is a perspective view of the static eliminator of FIG. 2 viewed from the rear side.
2A and 2C, the photosensitive drum 7 is illustrated by a dotted line for reference (see FIGS. 4A, 4C, 10A and 10A described later). The same applies to FIG. 10C).

  Here, since the charge remains on the outer peripheral surface of the photosensitive drum 7 after the transfer of the toner image, when the outer peripheral surface of the photosensitive drum 7 is charged at the next image formation, as described above, the electric charge remains in the width direction. Therefore, it is necessary to remove in advance all residual charges on the outer peripheral surface of the photosensitive drum 7 so that the outer peripheral surface after charging is uniform in the width direction. Therefore, every time the transfer of the toner image from the photosensitive drum 7 to the recording medium 11 is completed, the static eliminator 10 removes the charge remaining on the outer peripheral surface of the photosensitive drum 7 in preparation for the next image formation.

As shown in FIG. 2B and FIG. 3, the static eliminator 10 includes a reflecting member 16 and a light source 22.
As shown in FIG. 3, the reflecting member 16 is, for example, an acrylic resin rod shape, and is long in the width direction. As shown in FIG. 2A, the reflecting member 16 has a substantially isosceles trapezoidal shape that narrows toward the front side when viewed from the right side. As shown in FIG. 2C, the reflecting member 16 is opposed to the outer peripheral surface of the photosensitive drum 7 from the front with a space therebetween. In this state, the right end of the reflecting member 16 is on the right side of the right end of the photosensitive drum 7, and the left end of the reflecting member 16 is on the left side of the left end of the photosensitive drum 7. That is, the reflecting member 16 is opposed from the front to the entire width direction of the outer peripheral surface of the photosensitive drum 7. In the reflecting member 16, the rear surface is opposed to the outer peripheral surface of the photosensitive drum 7 from the front with an interval. The distance in the front-rear direction between the rear surface of the reflecting member 16 and the outer peripheral surface of the photosensitive drum 7 is constant in the width direction.

  Here, the rear surface of the reflecting member 16 is formed with a recess 16A that is recessed toward the direction away from the photosensitive drum 7 (front side) so that the rear side that is the photosensitive drum 7 side is opened. As shown in FIG. 3, the recess 16 </ b> A has a substantially U shape when viewed from the width direction and is long in the width direction. Specifically, the width direction dimension of the recess 16 </ b> A is slightly smaller than the width direction dimension of the reflecting member 16. In the recess 16A, the open end X on the photosensitive drum 7 side (rear side) is wider in the vertical direction than the deepest portion Y on the front side when viewed from the width direction.

  The recess 16A is partitioned from the left side by the left wall 14 of the reflecting member 16, and is not exposed to the left side. On the other hand, a substantially U-shaped notch 15A having the same size as the recess 16A when viewed from the width direction is formed on the right wall 15 of the reflecting member 16, and the recess 16A is formed through the notch 15A. Exposed to the right. That is, the recess 16A is exposed to the rear side and the right side, and the rear portion and the right portion exposed in the recess 16A are continuous with each other. The reflecting member 16 is formed with an inner surface 16B that defines such a recess 16A. Similarly to the recess 16A, the inner surface 16B is substantially U-shaped when viewed from the width direction and is long in the width direction. The inner surface 16B is painted, for example, in white so that light can be reflected (diffused) well. For the same purpose, the inner surface 16B may be plated, or may be subjected to embossing so as to form minute irregularities. Note that the reflecting member 16 itself may be formed of a white resin.

  As shown in FIG. 2C, the concave portion 16 </ b> A is provided with a plurality of convex portions 17 protruding rearward from the inner surface 16 </ b> B on the deepest portion Y side, and is integrated with the reflecting member 16. A reflective surface 18 is formed on the rear right side of each convex portion 17 so as to extend obliquely to the left rear side so as to approach the photosensitive drum 7 toward the left side. As shown in FIG. 2B, the reflection surface 18 has a semicircular shape that bulges toward the deepest portion Y (specifically, the right front side) of the recess 16A when viewed from the rear side. Similarly to the inner surface 16B described above, the reflecting surface 18 is also painted in white, plated, or textured so that light can be favorably reflected. Moreover, the convex part 17 itself which has the reflective surface 18 may be formed with white resin. The plurality of convex portions 17 are arranged along the width direction. Specifically, as shown in FIG. 2 (c), in the convex portions 17 adjacent to the left and right, the right convex portion 17 is formed with a flat surface continuously extending from the left end of the reflecting surface 18 to the front side. The front end of the flat surface is continuous with the right end of the reflecting surface 18 of the left convex portion 17.

  These convex portions 17 are provided such that the distance between the front and rear facing the photosensitive drum 7 decreases toward the left convex portion 17. In other words, the left convex portion 17 is located closer to the photosensitive drum 7, and when all the convex portions 17 are viewed together, these convex portions 17 gradually move to the rear side toward the left convex portion 17. Sticks out. The leftmost convex portion 17 is located at the left end of the concave portion 16 </ b> A and is closer to the photosensitive drum 7 than the other convex portions 17.

Further, in the substantially U-shaped concave portion 16A as viewed from the width direction (see FIG. 3), the left convex portion 17 protrudes closer to the photosensitive drum 7 side (opening end X side of the concave portion 16A). Accordingly, as shown in FIG. 2B, the reflecting surface 18 becomes larger in the vertical direction, and as a result, the area of the reflecting surface 18 is increased.
Then, as shown in FIG. 2C, the inclination angle θ with respect to the width direction of the reflective surface 18 that extends obliquely to the left rear side is larger for the left convex portion 17. Specifically, the inclination angle θ of the reflection surface 18 of the rightmost convex portion 17 is a predetermined value, for example, less than 45 °, and the inclination angle θ gradually increases toward the left convex portion 17.

As shown in FIG. 1, since the reflecting member 16 is connected to the housing 2, the reflecting member 16 is supported by the housing 2 and becomes a part of the process cartridge 1. The reflecting member 16 may be formed integrally with the housing 2 as a part of the housing 2.
2B and 2C, the light source 22 is disposed on the right side of the reflecting member 16, is supported on the above-described image forming apparatus main body side (not shown), and reflects the reflecting member 16. It faces the notch 15A of the right wall 15 from the right side with a gap (see also FIG. 3). As described above, since the reflecting member 16 is long in the width direction while facing the outer peripheral surface of the photosensitive drum 7 from the front (see FIG. 2C), the light source 22 disposed on the right side of the reflecting member 16 is It can be seen that the image forming apparatus main body (not shown) is disposed laterally in the central axis direction (width direction) of the photosensitive drum 7. In this state, the light source 22 can emit light to the left side along the width direction. That is, as shown in FIG. 2B, the direction in which the optical axis 22A of the light source 22 extends (optical axis direction) is the width direction, and the direction in which the central axis of the photosensitive drum 7 extends (see FIG. 2C). And parallel.

The static eliminator 10 having such a configuration operates after the transfer of the toner image from the photosensitive drum 7 to the recording medium 11 as described above.
Specifically, referring to FIG. 2C, the light source 22 emits light after the toner image is transferred, and the light from the light source 22 travels to the left along the width direction. Then, this light enters the recess 16A from the notch 15A of the reflection member 16, and proceeds to the left along the width direction in the recess 16A. At this time, since the photosensitive drum 7 side (rear side) is opened in the concave portion 16A as described above, a part of the light traveling to the left in the concave portion 16A is rearward from the open end X of the concave portion 16A. Naturally leaks to the side. In this way, the light that naturally leaks to the rear side includes light that is reflected by the inner surface 16B that defines the concave portion 16A and travels from the open end X of the concave portion 16A to the rear side in the course of traveling.

  Of the light traveling leftward within the recess 16A, the light that has reached the convex portion 17 hits the reflecting surface 18 of the convex portion 17 and is reflected to change the traveling direction. Specifically, since the reflecting surface 18 is inclined to the left rear side so as to approach the photosensitive drum 7 as it goes to the left side (as it is away from the light source 22) as described above, it is reflected by the reflecting surface 18. The light travels rearward and travels rearward through the open end X of the recess 16A.

  In this way, the light naturally leaked from the open end X of the concave portion 16A to the rear side while traveling to the left side and the light reflected by the reflecting surface 18 and proceeding to the rear side are combined to continue to the rear side. Irradiates the outer peripheral surface of the photosensitive drum 7. Then, by irradiating the outer peripheral surface of the photosensitive drum 7 with light from the reflecting member 16 in this way, the photosensitive drum 7 is exposed in the portion irradiated with the light, so that residual charges in this portion are removed. .

  Here, the light from the light source 22 is harder to reach as the distance from the light source 22 increases. Therefore, the light that has entered the concave portion 16A of the reflecting member 16 from the light source 22 is less likely to reach the left region farther from the light source 22 in the concave portion 16A. Accordingly, the amount of light that naturally leaks from the open end X of the recess 16A to the rear side while traveling to the left side of the light entering the recess 16A decreases toward the left side farther from the light source 22. . In this case, the amount of light (irradiation amount) applied to the photosensitive drum 7 from the reflecting member 16 may decrease as it goes to the left side farther from the light source 22.

  Therefore, the reflection surface 18 of the convex portion 17 functions so that the irradiation amount does not decrease even when the irradiation amount is far from the light source 22. Specifically, as described above, the left-side convex portion 17 (that is, the convex portion 17 away from the light source 22) has a smaller facing distance from the photosensitive drum 7, and the reflective surface 18 becomes larger. Furthermore, the inclination angle θ with respect to the width direction of the reflecting surface 18 is large.

  Therefore, the light that reaches the convex portion 17 after traveling through the concave portion 16A can be reliably reflected toward the photosensitive drum 7 as the reflecting surface 18 of the convex portion 17 on the left side farther from the light source 22 is reached. Thereby, even if the amount of light that naturally leaks from the open end X of the concave portion 16A to the rear side in the course of traveling decreases toward the left side farther from the light source 22, the convex portion 17 located far from the light source 22 instead. The amount of light reflected by the reflection surface 18 and traveling rearward increases.

  Therefore, even toward the left side far from the light source 22, the amount of light that naturally leaks from the open end X of the concave portion 16 </ b> A to the rear side in the course of traveling, and reflected (diffused) by the reflecting surface 18 of the convex portion 17 to the rear side. Since the total amount with the amount of traveling light hardly decreases, the amount of light irradiated from the reflecting member 16 onto the photosensitive drum 7 becomes substantially uniform in the width direction. Thereby, in this static elimination apparatus 10, the residual electric charge of the outer peripheral surface of the photosensitive drum 7 can be removed uniformly in the width direction.

Then, since the photosensitive drum 7 rotates after the toner image is transferred, the light from the reflecting member 16 is irradiated to the entire area in the circumferential direction with respect to the photosensitive drum 7. The residual charge is uniformly removed.
In FIG. 4, FIG. 4A is a right side view of the reflecting member of the static eliminator according to the second example, and FIG. 4B is a rear view of the static eliminator according to the second example. FIG.4 (c) is BB arrow sectional drawing of FIG.4 (b). FIG. 5 is a perspective view of the static eliminator of FIG. 4 as viewed from the rear side. 6A is a right side view of the reflecting member of the static eliminator according to the third example, and FIG. 6B is a rear view of the static eliminator according to the third example. FIG. 7 is a perspective view of the static eliminator of FIG. 6 viewed from the rear side. 8A is a right side view of the reflecting member of the static eliminator according to the fourth example, and FIG. 8B is a rear view of the static eliminator according to the fourth example. FIG. 9 is a perspective view of the static eliminator of FIG. 8 viewed from the rear side. 10 (a) is a right side view of the reflecting member of the static eliminator according to the fifth example, and FIG. 10 (b) is a rear view of the static eliminator according to the fifth example. FIG.10 (c) is CC sectional view taken on the line of FIG.10 (b). FIG. 11 is a perspective view of the static eliminator of FIG. 10 viewed from the rear side.

In the reflecting member 16 of the static eliminator 10 according to the first example described above, the inclination angle θ with respect to the width direction of the reflecting surface 18 increases as the left convex portion 17 (the convex portion 17 away from the light source 22) increases. (See FIG. 2 (c)).
Instead, the inclination angle θ with respect to the width direction of the reflecting surface 18 is less than 45 °, for example, in each convex portion 17 like the reflecting member 16 of the static eliminator 10 according to the second example shown in FIG. It may be the same at a predetermined value.

  Further, in the reflecting member 16 of the static eliminator 10 according to the first and second examples, the recess 16A is substantially U-shaped when viewed from the width direction (the optical axis direction of the light source 22) (FIG. 2A). As shown in the reflecting member 16 of the static eliminator 10 according to the third example shown in FIG. 6, FIG. 4 (a) and FIG. V shape may be sufficient. In this case, the recess 16A (inner surface 16B) has a triangular shape that narrows toward the deepest portion Y (see FIG. 6A).

Further, in the static eliminator 10 according to the first and second examples, the reflecting member 16 has a substantially isosceles trapezoidal shape that narrows toward the front side when viewed from the right side (FIG. 2A and FIG. 4 (a)), as in the fourth example shown in FIG. 8 (a), the reflecting member 16 itself may have a substantially U-shape, similar to the substantially U-shaped recess 16A.
Further, in the reflecting member 16 of the static eliminator 10 according to the second example, the interval between the reflecting surfaces 18 adjacent to the left and right is substantially constant (see FIG. 4C), but is shown in FIGS. As in the fifth example, as the distance from the light source 22 increases toward the left side, the interval between the reflective surfaces 18 adjacent to the left and right may be reduced.
<Effect>
(1) As shown in FIG. 2 (c), in this process cartridge 1, the reflecting member 16 is disposed on the outer peripheral surface of the photosensitive drum 7 so as to face the central axis direction (width direction) of the photosensitive drum 7. On the other hand, a light source 22 is arranged. Light from the light source 22 is reflected by the reflecting member 16 toward the photosensitive drum 7. As a result, the outer peripheral surface of the photosensitive drum 7 is exposed, and the electric charge on the outer peripheral surface of the photosensitive drum 7 is removed.

  The reflecting member 16 has a recess 16A that is recessed toward the direction away from the photosensitive drum 7 so that the photosensitive drum 7 side is opened, and the open end X on the photosensitive drum 7 side is wider than the deepest portion Y (see FIG. (See also Fig. 2 (a) and Fig. 3). The concave portion 16 </ b> A has a reflection surface 18 that reflects light from the light source 22 toward the photosensitive drum 7, and is provided with a plurality of convex portions 17 that protrude toward the photosensitive drum 7. Therefore, in the reflecting member 16, the light from the light source 22 is reflected toward the photosensitive drum 7 by the reflecting surfaces 18 of the plurality of convex portions 17 while traveling through the concave portion 16 </ b> A. Here, since the photosensitive drum 7 side is opened in the recess 16A, the reflecting member 16 can reflect the light traveling in the recess 16A toward the photosensitive drum 7 without leakage. Thereby, the electric charge of the outer peripheral surface of the photosensitive drum 7 can be effectively removed.

  And since the opposing space | interval of the some convex part 17 and the photosensitive drum 7 becomes small as it leaves | separates from the light source 22, the reflective surface 18 of the convex part 17 in the location which is separated from the light source 22 and cannot fully reach light is The light that has arrived from the light source 22 can be reliably reflected toward the photosensitive drum 7. Accordingly, it is possible to suppress a reduction in the amount of light reflected from the reflecting member 16 to the photosensitive drum 7 (same as the irradiation amount described above) as the distance from the light source 22 increases along the central axis direction of the photosensitive drum 7. Therefore, since the reflecting member 16 can uniformly reflect (can irradiate) the light from the light source 22 to the entire region in the central axis direction of the photosensitive drum 7, the charge on the outer peripheral surface of the photosensitive drum 7. Can be removed uniformly over the central axis direction.

As described above, the concave member 16A is formed in the reflective member 16 without bending the entire reflective member 16, and a plurality of convex portions 17 are provided in the concave portion 16A, while downsizing (reducing manufacturing cost) is achieved. The electric charges on the outer peripheral surface of the photosensitive drum 7 can be uniformly removed over the central axis direction of the photosensitive drum 7. In particular, since the charge on the outer peripheral surface of the photosensitive drum 7 can be removed only by providing the reflecting member 16 in addition to the light source 22, it is not necessary to provide a member for guiding the light from the light source 22 to the photosensitive drum 7 separately from the reflecting member 16.
(2) Since the convex portion 17 farther from the light source 22 has a larger reflective surface 18 (see FIG. 2B), the reflective surface 18 of the convex portion 17 at a location where it is difficult for light to reach sufficiently away from the light source 22 The light that has arrived from the light source 22 can be reliably reflected toward the photosensitive drum 7. As a result, a sufficient amount of light reflection from the portion away from the light source 22 in the reflecting member 16 to the photosensitive drum 7 can be secured, so that the charge on the outer peripheral surface of the photosensitive drum 7 is more uniform over the central axis direction. Can be removed.
(3) In the reflecting member 16 according to the fifth example shown in FIG. 10, as the distance from the light source 22 increases, the interval between the adjacent reflecting surfaces 18 decreases, so that it is adjacent to the light source 22 where it is difficult for light to reach sufficiently. The matching reflecting surface 18 can continuously reflect the light from the light source 22 toward the photosensitive drum 7 at a high frequency (see FIG. 10C). As a result, a sufficient amount of light reflection from the portion away from the light source 22 in the reflecting member 16 to the photosensitive drum 7 can be secured, so that the charge on the outer peripheral surface of the photosensitive drum 7 is more uniform over the central axis direction. Can be removed.
(4) As shown in FIG. 2C, since the plurality of convex portions 17 are arranged along the optical axis direction (width direction) of the light source 22, the reflection surface 18 of these convex portions 17 Light traveling in the axial direction can be reflected toward the photosensitive drum 7 without leakage.

Further, since the reflection surface 18 of each convex portion 17 is inclined so as to approach the photosensitive drum 7 as it is away from the light source 22, the light from the light source 22 can be reliably reflected toward the photosensitive drum 7. .
And since the inclination angle θ with respect to the optical axis direction of the reflective surface 18 is larger as the convex portion 17 is farther from the light source 22, the reflective surface 18 of the convex portion 17 is located at a location where it is difficult to reach light away from the light source 22. The amount of light reflected from the light source 22 to the photosensitive drum 7 can be increased. As a result, a sufficient amount of light reflection from the portion away from the light source 22 in the reflecting member 16 to the photosensitive drum 7 can be secured, so that the charge on the outer peripheral surface of the photosensitive drum 7 is more uniform over the central axis direction. Can be removed.
(5) The recess 16A is substantially U-shaped or substantially V-shaped when viewed from the optical axis direction of the light source 22 (see FIGS. 2A, 3, 6A, and 7). It is possible to easily form the concave portion 16A in which the open end X on the photosensitive drum 7 side is wider than the deepest portion Y.
<Modification>
In the above-described embodiment, the laser printer is illustrated in which the electrostatic drum image is formed by exposing the photosensitive drum 7 with a laser as shown in FIG. The present invention can be applied to all types of electrophotographic image forming apparatuses that form images by forming latent images.

It is a typical left sectional view showing one embodiment of a process cartridge concerning the present invention. FIG. 2A is a right side view of the reflecting member of the static eliminator according to the first example, and FIG. 2B is a rear view of the static eliminator according to the first example. ) Is a cross-sectional view taken along the line AA in FIG. It is the perspective view which looked at the static elimination apparatus of FIG. 2 from the rear side. FIG. 4A is a right side view of the reflecting member of the static eliminator according to the second example, and FIG. 4B is a rear view of the static eliminator according to the second example. ) Is a cross-sectional view taken along the line BB in FIG. It is the perspective view which looked at the static elimination apparatus of FIG. 4 from the rear side. FIG. 6A is a right side view of the reflecting member of the static eliminator according to the third example, and FIG. 6B is a rear view of the static eliminator according to the third example. It is the perspective view which looked at the static elimination apparatus of FIG. 6 from the rear side. FIG. 8A is a right side view of the reflecting member of the static eliminator according to the fourth example, and FIG. 8B is a rear view of the static eliminator according to the fourth example. It is the perspective view which looked at the static elimination apparatus of FIG. 8 from the rear side. FIG. 10A is a right side view of the reflecting member of the static eliminator according to the fifth example, FIG. 10B is a rear view of the static eliminator according to the fifth example, and FIG. ) Is a cross-sectional view taken along the line CC in FIG. It is the perspective view which looked at the static elimination apparatus of FIG. 10 from the rear side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Process cartridge 7 Photosensitive drum 10 Static elimination apparatus 16 Reflective member 16A Concave part 17 Convex part 18 Reflecting surface 22 Light source X Open end Y Deepest part (theta) Inclination angle

Claims (10)

A static eliminator that removes the charge on the outer peripheral surface of the photoreceptor,
A light source disposed laterally in the direction of the central axis of the photoconductor, and a reflecting member that is disposed to face the outer peripheral surface of the photoconductor and reflects light from the light source toward the photoconductor.
The reflecting member is recessed toward the direction away from the photoconductor so that the photoconductor side is opened, and a recess having an open end on the photoconductor side wider than the deepest portion is formed.
The concave portion has a reflecting surface that reflects light from the light source toward the photoconductor, and a plurality of convex portions that protrude toward the photoconductor side are spaced apart from the light source as the facing distance from the photoconductor is increased. A static eliminator provided to be small.   The static eliminator according to claim 1, wherein the convex portion that is farther from the light source has a larger reflection surface.   3. The static eliminator according to claim 1, wherein an interval between the reflecting surfaces adjacent to each other decreases as the distance from the light source increases. The plurality of convex portions are arranged along the optical axis direction of the light source,
The reflective surface of each of the convex portions is inclined so as to approach the photoconductor as the distance from the light source increases.
The static eliminator according to claim 2, wherein the convex portion farther from the light source has a larger inclination angle with respect to the optical axis direction of the reflecting surface.   5. The static eliminator according to claim 1, wherein the recess is substantially U-shaped or substantially V-shaped when viewed from the optical axis direction of the light source. A process cartridge installed in the image forming apparatus main body,
A photoconductor and an outer peripheral surface of the photoconductor are arranged opposite to each other, and light from a light source arranged on a side in the central axis direction of the photoconductor in the image forming apparatus main body is reflected toward the photoconductor. A reflective member,
The reflecting member is recessed toward the direction away from the photoconductor so that the photoconductor side is opened, and a recess having an open end on the photoconductor side wider than the deepest portion is formed.
The concave portion has a reflecting surface that reflects light from the light source toward the photoconductor, and a plurality of convex portions that protrude toward the photoconductor side are spaced apart from the light source as the facing distance from the photoconductor is increased. A process cartridge which is provided to be small.   The process cartridge according to claim 6, wherein the reflective surface is larger as the convex portion is farther from the light source.   The process cartridge according to claim 6, wherein an interval between the reflecting surfaces adjacent to each other decreases as the distance from the light source increases. The plurality of convex portions are arranged along the optical axis direction of the light source,
The reflective surface of each of the convex portions is inclined so as to approach the photoconductor as the distance from the light source increases.
The process cartridge according to claim 7, wherein the convex portion farther from the light source has a larger inclination angle with respect to the optical axis direction of the reflecting surface.   10. The process cartridge according to claim 6, wherein the recess is substantially U-shaped or substantially V-shaped when viewed from the optical axis direction of the light source.

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