JPH0723794Y2 - Electrophotographic device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial application field" The present invention relates to a grounding mechanism for various parts arranged on a recording material conveying path in an electrophotographic apparatus, and in particular, an optical scanning unit and the like arranged in the apparatus. Generate control signals to the electrical components of
The present invention relates to an improvement of an electrophotographic apparatus in which a control unit for sending out is arranged at a portion which directly or indirectly faces the recording material conveyance path.

[Prior Art] Conventionally, a feeding mechanism, a transfer unit, and a fixing unit are sequentially arranged on a recording material conveyance path formed in an apparatus, and the recording material accumulated in a recording material storage unit is fed by the feeding mechanism. Each sheet is guided onto the peripheral surface of the transfer position of the image carrier one by one at an appropriate timing, and then the toner image carried on the image carrier is transferred to the recording material side by transfer means such as discharge and pressure contact applied from the back side. An electrophotographic apparatus used as a copying machine, a printer, a facsimile, or a composite machine of these, in which the transferred unfixed toner image is fixed by a fixing device located on the downstream side of the conveyance path. It is publicly known that each of the parts arranged on such a conveying path retains the electrostatic charge of the sheet-shaped recording material itself or the toner image provided on the recording material, and is not used in the discharge-generating type transfer device. When a discharge occurs, the area around the transfer device is cut off. The residual charge is charged on the edge cover, etc., and when toner transfer or fixing to the recording material is performed with the static charge or residual charge remaining, unfixed toner adhered on the recording material due to the static charge. Image distortion occurs and it becomes difficult to form a clear image.

Therefore, in the conventional apparatus, the ground wire and the ground plate are provided for each of the components such as the paper feeding unit, the transfer unit, and the fixing unit, which are present on the recording material conveyance path, in which the electrostatic charge may remain or be charged. , And these grounding members are connected to the grounding external terminals on the apparatus main body side, respectively.

"Problems to be solved by the invention" However, attaching the ground wire to each part in the apparatus in this way complicates the assembly work for fixing the ground wire to each part using a screw or the like. Is happening,
Since the ground wire is routed inside the device from each of the respective parts to the external terminal for grounding, the layout configuration of the respective parts is restricted accordingly, and the ground wire is easily broken. .

Furthermore, in order to facilitate maintenance and replacement of parts,
In recent years, many configurations have been adopted in which each of the above components is unitized. However, if the ground wire as described above is connected to each unit, the unit cannot be replaced unless the ground wire is removed, and maintenance work is complicated. Turn into.

In view of the drawbacks of the prior art, the present invention makes it easy to electrically connect a cover body of a control box provided below the recording material conveyance path to a part of each of the above-mentioned parts, without providing a special ground member. The purpose is to provide a grounding function with a simple structure, thereby eliminating complications in assembly, achieving free maintenance, and preventing various accidents caused by routing the grounding wire inside the device.

“Means for Solving Problems” In laser printers and other various devices utilizing electrophotographic technology, for example, various devices incorporated in the apparatus, such as generating and transmitting a modulation signal to be transmitted to an optical scanning unit, A control unit for generating and transmitting a control signal for control is incorporated, and the control unit is a magnetic field generated during various high-voltage discharges or development during the electrophotographic process on the apparatus main body, or the recording material described above. Alternatively, it is necessary to electromagnetically conceal or block the control unit in order to prevent malfunctions caused by various noises such as electrostatic charges charged on the toner, etc. It is customary to cover the unit with a cover member.

Therefore, the present invention effectively utilizes the cover member of such a control unit so as to directly or indirectly face the cover member along the recording material conveying path, and cut and raise the cover member so as to remove the cover member. It is a gist of the present invention that a part of the present invention is projecting and the projecting portion is electrically connected to at least one component located on the transport path.

In this case, it is generally preferable that the cover member is arranged face-to-face with an insulating frame body for installing each component along the transport path, but the technical scope of the present invention is limited to this. It is not something that will be done.

[Operation] According to the technical means, all or at least a part of the feeding unit, the transfer unit, the fixing unit, and the like arranged along the recording material conveying path is electrically connected to the groundable cover member. Since they are connected, it is not necessary to attach a ground wire or a ground plate to each of the above parts. As a result, the assembly work is eliminated and these ground wires are routed inside the device. There will be no restrictions on various accidents and layout configuration of each part.

Further, since the respective parts and the cover member are merely in mechanical contact with each other, even when the respective parts are unitized, they can be easily attached and detached, and the maintenance work does not become complicated.

Further, the protruding portion is formed by the cut and raised means of the cover member,
The electrical connection is made more reliable by mechanically contacting each of the parts by the elastic force of the cutting and raising means.

Further, by arranging the cover member face-to-face with an insulating frame body for installing each component along the transport path, the influence of various noises on the control unit side can be minimized.

[Embodiment] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but merely illustrative examples. Nothing more than.

First, a schematic configuration of a laser printer according to this embodiment will be described based on the overall cross-sectional view of FIG. 1. In this embodiment, an upper main body A, a lower main body B, and a lower main body B which can be divided around a fulcrum are used. A lower frame body C made of an insulating resin, which is located on the lower side and extends along the recording material conveyance path to function as a partition plate, and is formed below the lower body B via the lower frame body C. Control unit storage space D.

On the upper body A side, from the right side in the figure, the upper frame body 1
An optical scanning unit 2 directly attached to the upper surface, a developing unit 3 disposed obliquely below the optical scanning unit 2 and detachably attached along a guide groove of the upper frame 1, and a facing arrangement with the developing unit 3. Further, the photosensitive drum 4, the cleaning member 5, the drum unit 7 in which the charger 6 and the like are housed, and the upper paper ejection guide 8a forming a part of the paper ejection unit 8 are mounted. The drum unit 7 is constructed so that it can be pressed by a coil spring 9 fixed to the upper frame 1 side, so that when the upper body A is closed, the drum shaft 4a is attached to the U-groove-shaped support 10 provided on the lower body B side. Mated,
It can be positioned at a predetermined position by the biasing force of the coil spring 9.

On the other hand, on the lower main body B side, along the recording material conveying path, a recording material storage stand 11, a paper feed roller 12, and a friction plate 13 on the free end side are attached, and the friction plate 13 is fed by a leaf spring 14. A paper feed separator 15 which is pressed against the peripheral surface of the roller 12, a registration roller 16 which guides the recording material fed by the separator 15 to a transfer position at a predetermined timing, and a transfer which is arranged so as to face the lower peripheral surface of the drum 4. Container 17, transport guide formed on the upper surface side of the lower frame body C
18, a fixing unit 20 for thermally fixing an unfixed toner image, a paper discharge unit 8b provided on the downstream side of the fixing unit 20, and the like are incorporated, and as is well known, a recording material placed on a storage base 11 is supplied. While being fed by the paper roller 12, only one recording material is fed to the entrance end of the registration roller 16 by the separating function of the friction plate 13, while the deflection beam emitted from the optical scanning unit 2 on the photosensitive drum 4 side. The latent image exposed on the basis of the above is visualized by a developing device, and the recording material is inserted into the transfer position so as to be coincident with the tip of the visualized toner image, and undetermined on the recording material by the transfer device 17. After the transferred toner image is transferred, it is sent to the fixing unit 20 via the conveyance guide 18, and after fixing the image, it is discharged to the toner portion 19 formed on the upper surface side of the upper main body A via the paper discharge unit 8. It

On the other hand, the lower body B is extended along the recording material conveyance path.
In the lower frame body C for partitioning the control storage space D formed on the lower side thereof, a portion contacting the free end side of the leaf spring 14 of the paper feed separator 15, a portion facing the transfer device 17, and a fixing unit 20. Rectangular through holes 31a to 31c are drilled in the portions corresponding to the installation surface of the bottom plate.

Further, the control unit 30 disposed in the lower storage space D of the lower frame body C has an upper cover body 32 made of metal bent along the lower surface shape of the lower frame body C, and the cover body 32 is connected to an external earth. While electrically connecting to the terminal 34, a part of the upper surface corresponding to the through holes 31a to 31c is cut and raised, and the cut and raised portions 33a to 33c are separated from the paper feed through the through holes 31a to 31c. The free end side of the leaf spring 14 of the device 15, the shield cover 17a of the transfer device 17, and the bottom plate 24 of the fixing unit 20.
Each of them is elastically contactable.

According to such an embodiment, for example, on the paper feed separator 15 side, the friction plate 13 that is in sliding contact with the paper feed roller 12 is provided on the paper feed roller 15 side.
A conductive rubber having a frictional resistance higher than 12 and a support plate 15a for supporting the friction plate 13 formed of a metal material, so that the recording generated by the sliding friction between the paper feed roller 12 and the friction plate 13 The electrostatic charge of the material causes friction plate 13, support plate 15a, leaf spring 14
The cut-and-raised parts 33a to 33c that are in contact with the leaf spring 14 via
Flows from the upper cover body 32 to the external ground terminal 34, and the transfer device 17 is also shielded by the discharge during transfer in the same manner.
The residual charge charged on a flows from the cut-and-raised parts 33a to 33c to the external ground terminal 34 through the upper cover body 32, and also in the fixing unit 20, the static electricity charged from the recording material and the toner by inserting the unfixed toner image. An electric charge is passed through the fixing roller 21, the roller shaft 22, the fixing cover 23, and the bottom plate 24 from the cut-and-raised parts 33a to 33c to the upper cover body 32 and the external ground terminal 34.
Since each of the parts flows to each other, electrostatic charges and residual charges are not charged on the respective parts, and the disturbance of the image due to the residual charges and the like can be completely prevented.

Further, since the lower body B and the control unit 30 are shielded by the lower frame body C made of insulation, the electrostatic charge and discharge reduction generated on the apparatus body side are not propagated to the control unit side and are erroneous. There is no room for operation.

[Advantages of the Invention] As described above, according to the present invention, the cover body 32 of the control unit provided below the recording material conveying path is brought into electrical contact with a part of each component arranged on the recording material conveying path. By doing so, it is possible to provide a grounding function with a simple configuration without providing a special grounding wire or grounding plate, thereby eliminating complications in assembly, achieving free maintenance, and further grounding equipment. It has various remarkable effects such as being able to prevent various accidents caused by internal routing.

[Brief description of drawings]

1 and 2 show a laser printer according to an embodiment of the present invention, FIG. 1 is an overall sectional view thereof, and FIG. 2 is a perspective view of an upper cover body forming a cover body of a control unit. 30: control unit, 32: conductive cover member, 33a
~ 33c: projecting portion, 15, 17, 20: recording material, parts arranged along the conveying path, C: insulating frame body

Claims (3)

[Scope of utility model registration request] 1. A recording material transporting a groundable conductive cover member for electromagnetically shielding a control unit for generating and transmitting a control signal for controlling various devices incorporated in an electrophotographic apparatus. At least a part of the road is directly or indirectly face-to-face, and a part of the cover member that is face-to-face is projected to electrically connect the projecting portion and at least one component located on the transport path. Electrophotographic device characterized by being connected 2. The electrophotographic apparatus according to claim 1, wherein the cover member is face-to-face arranged through an insulating frame body for installing each component along the transport path. 3. A utility model registration claim characterized in that the projecting portion is formed by a cut-and-raised means of a cover member, and is mechanically contacted with the respective parts by elastic force of the cut-and-raised means. Electrophotographic apparatus according to claim 1