JP4619025B2 - Charging device in image forming apparatus - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device in an image forming apparatus such as a copying machine, a printer, a facsimile, or a composite machine using an electrophotographic method, and more particularly to a corotron type or scorotron type charging device that can be attached to and detached from the image forming apparatus body. Is.

  In an image forming apparatus such as a copying machine, a printer, a facsimile, or a composite machine using an electrophotographic method, a photosensitive member (image carrier) is charged and then exposed to image data to form a latent image. The latent image is developed with toner to obtain a toner image, and the density of the toner image greatly depends on the surface potential of the photoreceptor forming the electrostatic latent image. Therefore, in order to obtain an image having an appropriate density with good reproducibility, it is necessary to uniformly apply a predetermined surface potential to the photoconductor (image carrier) with good reproducibility.

  In such a charging device, a charging wire is extended in the width direction so as to face the photosensitive member (image carrier), and the surface of the photosensitive member (image carrier) is applied by applying a high voltage to the charging wire. There are a corotron method for charging, a scorotron method for applying a bias voltage by providing a charging control grid called a scorotron at an open portion of a shield case in the corotron charging device.

  Among these, the scorotron charging device can reduce uneven charging potential on the surface of the photosensitive member (image carrier) by providing a charging control grid. However, these corotron and scorotron charging devices are capable of discharging. Discharge products such as ozone and nitrogen oxides generated by stagnation may accumulate in the shield case and adhere to the charging wire, causing discharge unevenness. Also, the generated nitrogen oxides are relatively heavy substances. Therefore, there is a concern that it may be attached to the photoconductor (image carrier) and cause a problem.

  For this reason, such a corotron or scorotron charging device must be detachable at any time for cleaning or inspection. For example, Patent Document 1 discloses that a charging device is a photosensitive member (image carrier). ) Is attached to and supported by the connector provided on the gantry, and is installed around the photosensitive member (image carrier), since one connector is provided at two locations to supply two types of high pressure. It is extremely difficult to connect to both power sources, and because the mounting positions of the connector structure and connection are close, the structure for mounting and the wiring route for connection become complicated. Since this is inevitable, the corona voltage supply electrode and the grid voltage supply electrode are provided with steps in the axial direction of the photosensitive member (image carrier), and the respective electrodes are provided corresponding to the steps on the charging device side. Charging apparatus that can be mounted only by inserting the radial charging device photoreceptor (image bearing member) is proposed Te.

  In Patent Document 2, a roller is provided between the charging device and the photosensitive member (image carrier) in order to keep the distance between the charging device and the photosensitive member (image carrier) constant even when the charging device is attached or detached. The charging device is urged toward the roller side to keep the distance between the corona wire and the photosensitive member (image carrier) constant, but the power feeding device and the urging device are provided completely separately. The structure is complicated, so the roller is on the lower side, the power supply and grounding terminals are on the upper side, the pressing part that presses these power supply and grounding terminals, respectively, and the power supply part connected to the power supply are grounded A power feeding device is shown in which a power feeding electrode element and an installation electrode element, which are integrally connected to each other by a conductor, are fixed to a fixing part of the device.

JP-A-1-179960 JP-A-1-232367

  However, since the charging device disclosed in Patent Document 1 does not press the charging device itself against the photosensitive member (image carrier) side, the interval between the corona wire and the photosensitive member (image carrier) is always fixed. I am still worried about whether I can do it. Further, the charging device disclosed in Patent Document 2 requires a roller for making a certain distance between the charging device and the photosensitive member (image carrier) and a pressing member for pressing the charging device, and is complicated and requires a lot of man-hours for assembly. I need.

  Therefore, in the present invention, it is possible to regulate the movement of the charging device while keeping the distance between the charging device and the photosensitive member (image carrier) constant with a very simple configuration, and the number of parts can be reduced for assembly. It is an object to provide a charging device in an image forming apparatus that can be easily performed.

In order to solve the above problems, in the present invention,
It has a photoconductor that carries a toner image by an electrophotographic method and a charging device for charging the photoconductor. The charging device can be attached to and detached from the process unit, and the process unit can be attached to and detached from the image forming apparatus. A charging device in the image forming apparatus configured as described above,
The process unit exposes a charging device side contact to supply a high voltage from the image forming apparatus main body side to the charging device on the end side wall of the photoconductor, and a hole for positioning the charging device; The charging device has a locking rib that presses the charging device toward the photoreceptor and locks the movement, and the charging device is provided with a convex portion to be inserted into the positioning hole at the end portion, and a high-voltage contact member is disposed across the convex portion. The protruding portion is inserted into the positioning hole, and the locking rib abuts on a part of the high-voltage contact member to press the charging device against the photosensitive member by the spring force of the high-voltage contact member. The locking rib is in contact with the provided stepped portion, and the positioning of the charging device is restricted and fixed ,
The portion of the high-voltage contact member that is pressed to the photoconductor side by the locking rib is located below the lower surface of the locking rib, and is moved to the opposite side to the high-voltage power supply side to end the high-voltage power supply side. It is configured to be removable by lifting the part .

The pressure contact member in such charging device, used as a pressing member of a charging device lock member to the photosensitive member Direction by thereby positioning and fixing the charging device, the charging device as the conventional apparatus and the photosensitive member There is no need to provide a roller for keeping the distance constant or a member for pressing the charging device, and the movement of the charging device is regulated while keeping the distance between the charging device and the photosensitive member constant with a very simple configuration. In addition, since the attachment and detachment can be performed with one touch, it is possible to provide a charging device in an image forming apparatus that is advantageous in terms of cost, such as a small number of parts and easy assembly.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

  FIG. 1 shows a high-voltage contact member in which a convex portion provided at an end of a charging device in the image forming apparatus according to the present invention also serves as a member for locking the charging device and pressing in the direction of a photosensitive member (image carrier). FIG. 2 is a perspective view of a high-voltage contact member that also serves as a member for locking the charging device and pressing the photosensitive member (image carrier), and FIGS. 3 and 4 are images. FIG. 5 is a perspective view for explaining a method of mounting the charging device according to the present invention, in which a process unit in the forming apparatus is cut out so that a photosensitive member (image carrier) is exposed, and FIG. 5 is an end portion of the process unit in FIG. FIG. 6 is a perspective view showing a state where the charging device is mounted and locked, and FIG. 7 is an explanatory view when the charging device of the present invention is removed from the process unit.

In the figure, 1 is a charging device according to the present invention, 2 is a sheet metal such as phosphor bronze having both spring properties and conductivity, and a convex portion 3 provided at the end of the charging device 1 is bent as a high-voltage contact portion. the part 2 ₁ in hole 2 ₂ provided at an end portion fitted is fixed like in the charging device 1 bis, high voltage contact member having a locking portion 2 ₄ formed a step 2 _3, 4 the photosensitive member (image bearing member ) 5, a process unit having the charging device 1 of the present invention, a developing device (not shown), and the like that is detachable from the image forming apparatus, and 6 is a photosensitive member (image carrier) 5 in the process unit 4. the end side wall, positioning for positioning to expose the bent portion 2 ₁ of the high-voltage contact section of the high voltage contact member 2 for supplying a high voltage to the charging device 1 from the image forming apparatus body, the charging device 1 The hole 7 is a lock in the high-voltage contact member 2. Part 2 ₄ pressed to the photosensitive member (image bearing member) 5 side, a step 2 ₃ photoreceptor while restricting movement of the charging device 1 when led to the subsequent step 2 ₃ it (image bearing member) 5 side The rib to be pressed, 8 is a convex portion provided with a contact for grounding provided at the end opposite to the high-voltage power supply side, and 9 is for pressing the end for grounding toward the photoconductor (image carrier) 5 side. Spring member 10 for positioning, positioning hole for positioning the ground side end portion by inserting the convex portion 8, 11 a shield case accommodating a charging wire or a charging control grid, 12 a charging device 1 in the process unit 4 It is a storage part.

As shown in FIG. 2, the charging device 1 in the image forming apparatus according to the present invention is formed at the end portion of the high-voltage power supply side with a metal plate having both spring property and conductivity such as phosphor bronze. in hole 2 ₂ provided at the end portion is fitted to the bent portion 2 ₁ of the high-voltage contact section bis (not shown) to the convex portion 3 is secured to the charging device 1 and the like, the locking portion forming a step 2 ₃ A high-voltage contact member 2 having 2 ₄ is arranged.

On the other hand, on the process unit 4 side, as shown in FIG. 6, a high-voltage contact is provided on the side wall of the end portion of the photoconductor (image carrier) 5 to supply high voltage from the image forming apparatus main body side to the charging device 1. to expose the bent portion 2 ₁ of the high voltage contact section of the member 2, and the positioning holes 6 for positioning the charging device 1, the locking unit 2 ₄ a photosensitive body in the pressure contact member 2 (image bearing member) 5 side depression, and ribs 7 for pressing is provided a step 2 ₃ while restricting the movement of the charging device 1 to the photosensitive member (image bearing member) 5 side when that led to the subsequent step 2 ₃ it.

  Further, as shown in FIG. 7, the charging device 1 includes a convex portion 8 in which a contact for grounding is arranged at an end opposite to the high-voltage power supply side, and a photosensitive member (image carrier). ) A spring member 9 for pressing toward the 5 side is provided, and the process unit 4 is also provided with a positioning hole 10 for inserting the convex portion 8 and positioning the end on the ground side. Note that the charging wire and the charging control grid in the charging device 1 are housed in the shield case 11 shown in FIG. 1, and the shield case 11 shown in FIG. 1 is housed in the housing portion 12 provided in the process unit 4. ing.

  In the charging device 1 of the present invention configured as described above, the process unit 4 is provided with a convex portion 8 in which a contact for grounding is arranged at an end opposite to the high-voltage power supply side as shown in FIG. It is inserted into the positioning hole 10 until it hits the wall following the convex portion 8 and is stored in the storage portion 12 of the charging device 1 in the process unit 4 as shown in FIG. At this time, the opposite side of the charging device 1 to the high-voltage power supply side is pressed against the photosensitive member (image carrier) 5 by the above-described spring member 9 by a wall portion (not shown) in the process unit 4.

Further, since the high voltage power supply side of the charging device 1 is stored in the storage unit 12 of the charging device 1 in the process unit 4 in the state shown in FIG. 5, the charging device 1 is positioned in the process unit 4 in this state. moving towards the hole 6, per lock unit 2 ₄ in the high-pressure contact member 2 to the rib 7 provided in the process unit 4, a portion thereof is pressed by the photosensitive member (image bearing member) 5 ribs 7 this go over the lock unit _{2 4.}

Then, the charging device 1 step portion 2 ₃ in the high-pressure contact member 2 against the rib 7 can no longer move in the opposite side to the high pressure feed side, and sheet metal photoreceptors rib 7 is followed in this stepped section 2 ₃ (image The charging device 1 is pressed against the photosensitive member (image carrier) 5 side by the spring force of the high-voltage contact member 2 because the pressure is applied to the carrier member 5 side. Thus the charging device 1 is regulated movement is positioned at the step portion 2 ₃ in the high-pressure contact member 2, further pressing the photosensitive member of the step portion 2 ₃ by ribs 7 (image bearing member) pressed against the 5-side, the convex portion 3 is pressed against the photoconductor (image carrier) 5 side of the positioning hole 6 to be accurately positioned.

To remove the charging device 1 in this state from the process unit 4, the locking unit 2 ₄ press the latch portion 2 ₄ of high voltage contact member 2 in FIG. 6 to the photosensitive member (image bearing member) 5 side than the lower surface of the rib 7 If the entire charging device 1 is moved to the opposite side to the high-voltage power supply side and the high-voltage power supply side is lifted up, it can be easily removed.

  As described above, according to the present invention, the high voltage contact member 2 in the charging device 1 is used as a locking member of the charging device 1 and a pressing member in the direction of the photosensitive member (image carrier) 5, thereby charging the charging device. By positioning and fixing 1, there is no need to separately provide a roller for keeping the distance between the charging device and the photosensitive member (image carrier) constant and a member for pressing the charging device unlike the conventional device, With a very simple configuration, it is possible to regulate the movement of the charging device while keeping the distance between the charging device and the photosensitive member (image carrier) constant, and because it can be attached and detached with a single touch, the number of parts is small and assembly is possible. It is possible to provide a charging device in an image forming apparatus that can be easily performed and is advantageous in terms of cost.

  Since the movement of the charging device is regulated while keeping the distance between the charging device and the photosensitive member (image carrier) constant with a very simple configuration, and the attachment and detachment thereof can be performed with a single touch, in an inexpensive image forming apparatus. A charging device can be provided.

In the image forming apparatus according to the present invention, the convex portion provided at the end of the charging device is mounted with a high-voltage contact member that also serves as a member for locking the charging device and pressing the photosensitive member (image carrier). It is the perspective view which showed. FIG. 3 is a perspective view of a high-voltage contact member that also serves as a member for locking the charging device and pressing in the direction of the photoreceptor (image carrier). FIG. 3 is a perspective view for explaining a mounting method of the charging device of the present invention, in which a process unit in the image forming apparatus is cut out so that a photosensitive member (image carrier) is exposed. FIG. 3 is a perspective view for explaining a mounting method of the charging device of the present invention, in which a process unit in the image forming apparatus is cut out so that a photosensitive member (image carrier) is exposed. FIG. 5 is an enlarged view of the end side of the process unit in FIG. 4. It is a perspective view which shows the state which mounted | wore and locked the charging device. It is explanatory drawing when removing the charging device of this invention from a process unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Charging device 2 High voltage contact member 2 ₁ Bent part (high voltage contact part)
2 ₂ hole 2 ₃ step 2 ₄ lock part 3 convex part 4 process unit 5 photoconductor (image carrier)
6 Positioning hole 7 Rib 8 Protruding part 9 Spring member 10 Positioning hole 11 Shield case 12 Storage part

Claims (1)

It has a photoconductor that carries a toner image by an electrophotographic method and a charging device for charging the photoconductor. The charging device can be attached to and detached from the process unit, and the process unit can be attached to and detached from the image forming apparatus. A charging device in the image forming apparatus configured as described above,
The process unit exposes a charging device side contact to supply a high voltage from the image forming apparatus main body side to the charging device on the end side wall of the photoconductor, and a hole for positioning the charging device; The charging device has a locking rib that presses the charging device toward the photoreceptor and locks the movement, and the charging device is provided with a convex portion to be inserted into the positioning hole at the end portion, and a high-voltage contact member is disposed across the convex portion. The protruding portion is inserted into the positioning hole, and the locking rib abuts on a part of the high-voltage contact member to press the charging device against the photosensitive member by the spring force of the high-voltage contact member. The locking rib is in contact with the provided stepped portion, and the positioning of the charging device is restricted and fixed ,
The portion of the high-voltage contact member that is pressed to the photoconductor side by the locking rib is located below the lower surface of the locking rib, and is moved to the opposite side to the high-voltage power supply side to end the high-voltage power supply side. A charging device in an image forming apparatus, wherein the charging device is configured to be removable by lifting a portion .

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