JP2014194506A - Grounding structure of unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grounding structure of a unit capable of removing the unit with high workability while preventing a ground spring interposed between two units from jumping out.SOLUTION: In a grounding structure of a unit, a paper feed unit 1 and a drive unit 2 which are attachable to and detachable from a device body 1A are conducted via a ground spring 9, such that the paper feed unit 1 is grounded via the ground spring 9 and the drive unit 2. A large-diameter part 9A is formed in a center part of the ground spring 9 in a length direction, and the large-diameter part 9A is held within a recess 17A of a main body frame 17 while being contracted. While making free small-diameter parts 9B and 9C extending in both directions from the large-diameter part 9A, end portions of the small-diameter parts are brought into press-contact with the paper feed unit 1 and the drive unit 2, respectively.

Description

  The present invention relates to a unit grounding structure in which one unit is grounded via an earth spring and the other unit by connecting two units that can be attached to and detached from the apparatus body via an earth spring. .

  In an image forming apparatus such as a copying machine that forms an image on a sheet by electrophotography, a unit that can be attached to and detached from the apparatus main body is provided. When the unit includes a conductor, a charged charge is discharged. This may have a negative impact on the equipment and users, so the unit must be grounded. When there are two such units, if there is no conductor for grounding in the vicinity of one unit, the one unit needs to be grounded via the other unit. In such a case, the two units are connected by a ground wire, but both units are attached to and detached from the apparatus main body. Therefore, when these units are fastened with screws, the work at the time of attachment / detachment becomes complicated.

  Therefore, it is conceivable that an earth spring is interposed between the two units so as to contact the other in the mounted state, and one unit is grounded via the earth spring and the other unit.

  By the way, Patent Document 1 discloses an image forming apparatus in which a roller having a conductive support shaft rotatably supported by a conductive bearing is grounded by electrically connecting the roller to a grounded main body frame. As a roller installation structure, a configuration has been proposed in which a roller is grounded via a wire spring in which a grounding plate attached to the conductive bearing and a compression coil spring formed on both ends of the body frame are connected by a wire rod. .

JP 2008-197504 A

  By the way, when adopting a configuration in which two units that can be attached to and detached from the apparatus main body are connected to each other via an earth spring interposed between them, the earth spring needs to be fixed to one unit. For this reason, there are problems that the shape of the ground spring and the unit is complicated, the member cost is increased, and the assembling workability is lowered. In addition, if the spring constant of the ground spring is small, a grounding failure may occur. If the spring constant is large, the unit may pop out when attaching or detaching the unit, reducing workability. Must be set to a value.

  The present invention has been made in view of the above problems, and an object of the present invention is that a ground spring interposed between two units can be easily fixed to the unit with a simple shape. It is another object of the present invention to provide a unit grounding structure that makes it easy to set the spring constant of an earth spring to an appropriate value and allows the unit to be attached and detached with good workability.

In order to achieve the above object, according to the first aspect of the present invention, two units that can be attached to and detached from the apparatus main body are electrically connected to each other via an earth spring, so that one unit passes through the earth spring and the other unit. A grounding structure of a unit for grounding, wherein a large-diameter portion is formed at a central portion in the longitudinal direction of the earth spring, the large-diameter portion is held in a recessed manner in the concave portion of the apparatus main body, and extends in both directions from the large-diameter portion. The small-diameter portion is free and each end portion is pressed against each unit.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, both small diameter portions of the earth spring are honey-wound.

  According to the first aspect of the present invention, the large-diameter portion formed at the central portion in the longitudinal direction of the earth spring is held in a recess in the apparatus main body, and the small-diameter portions extending in both directions from the large-diameter portion are free. Since the ends are pressed against each unit and both units are made to conduct through the earth spring, the earth spring does not pop out even if the unit is removed, and the earth spring remains held in the recess of the device body. The unit can be removed with good workability.

  According to the second aspect of the present invention, since both small-diameter portions of the earth spring are honey-rolled, each small-diameter portion functions as a rigid body and does not have a spring property. For this reason, only the large diameter portion of the earth spring functions as a spring, and the apparent spring constant of the whole earth spring can be easily calculated.

1 is a perspective view of an image forming apparatus including a unit grounding structure according to the present invention. It is a perspective view which shows the earth structure of the unit which concerns on this invention. It is a perspective view which shows the earth structure of the unit which concerns on this invention. It is a plane sectional view showing the earth structure of the unit concerning the present invention. It is the sectional view on the AA line of FIG.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a perspective view of an image forming apparatus having a unit grounding structure according to the present invention. The illustrated image forming apparatus 10 is an in-body discharge type copier, and is provided at the upper part of the apparatus main body 10A. An image reading unit 11 is disposed, and a discharge tray 12 for in-body discharge is formed below the image reading unit 11. An operation unit 13 is provided at the front end of the image reading unit 11.

  Further, below the paper discharge tray 12 of the image forming apparatus 10, two upper and lower paper feed cassettes 15 and 16 that can be pulled out to the front side are installed. Each of the paper feed cassettes 15 and 16 has a plurality of sheets. (Not shown) are accommodated in a stacked state. Although not shown, the image forming unit 14 of the apparatus main body 10A includes a photosensitive drum as an image carrier, a charger for uniformly charging the surface of the photosensitive drum, and laser light on the surface of the charged photosensitive drum. A laser scanner unit (LSU) that scans the image to form an electrostatic latent image according to image information, and develops the electrostatic latent image formed on the photosensitive drum with toner as a developer to become a visible image as a toner image. Various processing devices such as a developing device, a transfer device that transfers a toner image formed on a photosensitive drum onto a sheet, and a fixing device that heats and pressurizes the toner image transferred on the sheet are accommodated. Yes.

  Incidentally, the image forming apparatus 10 shown in FIG. 1 is provided with a unit grounding structure according to the present invention. Details of the structure will be described below with reference to FIGS. 2 and 3 are perspective views showing the grounding structure of the unit according to the present invention, FIG. 4 is a plan sectional view showing the grounding structure, and FIG. 5 is a sectional view taken along line AA in FIG.

  In the apparatus main body 10A of the image forming apparatus 10 shown in FIG. 1, the paper feed unit 11 shown in FIGS. 2 to 4 and the drive unit 2 for driving the paper feed unit 11 are detachably mounted on the apparatus main body 10A. Here, the paper feeding unit 1 is a unit for conveying paper, and the input shaft 4 that projects horizontally from the housing 3 is a cup in which an output shaft 5 that extends horizontally from the drive unit 2 is biased by a spring 6. The ring 7 is detachably connected.

  The drive unit 2 is a unit that drives the paper feeding unit 1, and an electric motor 8 that is a drive source is fixed to the rectangular flat frame 2 </ b> A in a lateral state. An output shaft (motor shaft) (not shown) of the electric motor 8 is connected to the output shaft 5 through a gear train G composed of a plurality of gears, and the output shaft (motor shaft) of the electric motor 8 is rotated. Is decelerated via the gear train G and transmitted to the output shaft 5, and the rotation of the output shaft 5 is transmitted to the input shaft 4 of the paper feed unit 1 through the coupling 7 and connected to the input shaft 4 and the input shaft 4. A transport roller (not shown) is rotated at a predetermined speed to transport the paper.

  By the way, in the present embodiment, the paper feed unit 1 and the drive unit 2 are in a conductive state by a conductive earth spring 9 interposed therebetween. The paper feed unit 1 is grounded via the earth spring 9 and the drive unit 2.

  The ground spring 9 has a large-diameter portion 9A formed at the center in the axial direction, and small-diameter portions 9B and 9C extend from the large-diameter portion 9A in both directions. As shown in FIGS. 4 and 5, the ground spring 9 has a large-diameter portion 9 </ b> A that is contracted and held in a recess 17 </ b> A formed in the main body frame 17. Here, the concave portion 17A formed in the main body frame 17 is formed in a semi-cylindrical shape having an upper opening as shown in FIG. 5, and the large-diameter portion 9A of the earth spring 9 is shown in FIG. 4 in the concave portion 17A. The both ends of the large diameter portion 9A in the longitudinal direction are in contact with the inner surfaces of the end walls 17a and 17b of the recess 17A. The small-diameter portions 9B and 9C extending in both directions from the large-diameter portion 9A of the earth spring 9 penetrate through through holes formed in the end walls 17b and 17c of the concave portion 17A formed in the main body frame 17 as shown in FIG. The end portions of the small-diameter portions 9B and 9C are in a free state. As shown in FIG. 4, when the paper feed unit 1 and the drive unit 2 are mounted in the apparatus main body 10A, the paper feed unit 1 and the drive unit 2 are end portions of the small diameter portions 9B and 9C of the ground spring 9. Are pressed against each other.

  By the way, in this Embodiment, the small diameter parts 9B and 9C of the earth spring 9 are honey-wound and have no spring property, and only the large diameter part 9A has a spring property and functions as a spring. Accordingly, the small diameter portions 9B and 9C of the earth spring 9 function as rigid bodies, and the paper feed unit 1 and the drive unit 2 are in pressure contact with the end portions of the small diameter portions 9B and 9C of the earth spring 9 as shown in FIG. The large-diameter portion 9A of the ground spring 9 is pushed from both sides by the small-diameter portions 9B and 9C and is compressed in the recess 17A of the main body frame 17. In the present embodiment, one small diameter portion 9B of the ground spring 9 is formed to have a larger diameter than the other small diameter portion 9C.

  Thus, as described above, a paper feed unit is provided at each end of the small diameter portions 9B and 9C extending in both directions from the large diameter portion 9A of the ground spring 9 in which the large diameter portion 9A is held in a compressed state in the concave portion 17A of the main body frame 17. 1 and the drive unit 2 come into contact with each other, the paper feed unit 1 is grounded via the ground spring 9 and the drive unit 2, and the electric charge accumulated in the paper feed unit 1 is discharged to adversely affect other devices and users. The problem of affecting is resolved.

  As described above, according to the grounding structure of the present invention, the large diameter portion 9A formed at the center portion in the longitudinal direction of the ground spring 9 is held in the recessed portion 17A of the main body frame 17 so as to extend in both directions from the large diameter portion 9A. The extending small-diameter portions 9B and 9C are free, and their respective end portions are pressed into contact with the paper feed unit 1 and the drive unit 2, respectively, so that the units 1 and 2 are electrically connected to each other via the ground spring 9. Since the earth spring 9 has a simple shape in which a large diameter portion and a small diameter portion are connected on the same axis, it is easy to manufacture and is deformed as compared with an earth spring having a shape in which compression coil springs at both ends are connected by a wire. It is difficult to store and handle. In addition, it is easy to attach and fix to the apparatus. Even if one or both of the paper feed unit 1 and the drive unit 2 are removed, the ground spring 9 does not pop out, and the ground spring 9 remains held in the concave portion 17A of the main body frame 17, so that the paper feed unit 1 and the drive The unit 2 can be removed with good workability.

  In the present embodiment, since both the small diameter portions 9B and 9C of the earth spring 9 are honey-rolled, each small diameter portion 9B and 9C functions as a rigid body and does not have a spring property. For this reason, only the large-diameter portion 9A of the earth spring 9 functions as a spring, and an effect that the apparent spring constant of the whole earth spring 9 can be easily calculated is obtained.

  In the above embodiment, the paper feeding unit and the drive unit of the image forming apparatus have been described as examples of the detachable unit. However, the present invention is not limited to the grounding of any other unit that is electrically connected to each other via a ground spring. Of course, the same applies to the structure.

1 Paper feed unit (unit)
2 Drive unit (unit)
2A Drive unit frame 3 Paper feed unit housing 4 Paper feed unit input shaft 5 Drive unit output shaft 6 Spring 7 Coupling 8 Conduction motor 9 Earth spring 9A Large diameter portion of earth spring 9B, 9C Small diameter portion of earth spring 10 Copying machine DESCRIPTION OF SYMBOLS 10A Apparatus main body 11 Image reading part 12 Paper discharge tray 13 Operation part 14-16 Paper feed cassette 17 Main body frame 17A Main body frame recessed part 17a, 17b End wall of recessed part of main body frame G Gear train

Claims (2)

A unit grounding structure in which one unit is grounded via the earth spring and the other unit by connecting two units detachable with respect to the apparatus main body via an earth spring.
A large-diameter portion is formed at the center in the longitudinal direction of the earth spring, the large-diameter portion is contracted and held in a concave portion of the apparatus main body, and each end portion of the small-diameter portion extending in both directions from the large-diameter portion is free. A unit grounding structure, wherein the unit is configured to be pressed against each unit. 2. The grounding structure for a unit according to claim 1, wherein both small diameter portions of the ground spring are honey-wound.

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