JP3410431B2 - Electrophotographic equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus, and more particularly to grounding a control board and a power supply board for controlling the operation of the electrophotographic apparatus.

[0002]

2. Description of the Related Art Electrophotographic printers, copiers, fax machines, etc., are suitable for personal use.
There is a demand for smaller size and lighter weight. In particular, printers that use an optical system unit that uses polygons to form an image created from digital data on an image carrier,
Since it is also optimal for personal computer output, demand for personal use is increasing, and there is a strong demand for size reduction, weight reduction, and price reduction.

As is well known, however, the electrophotographic apparatus generally uses heat for fixing. Therefore, the size and weight of the electrophotographic apparatus are reduced while always considering the heat radiation of the fixing device and the influence of heat of the members in the vicinity. It is necessary to plan.

Therefore, in consideration of the above, the members such as the housing, which are not easily affected by the heat of the fixing unit, are made of non-conductive material such as injection-molded plastic, and the metal members are used only for the necessary portions. At the same time, efforts have been made to reduce the weight and price of the components themselves by carefully arranging small components in a dense manner.

However, in order to avoid the influence of noise, the control board for controlling the operation of the electrophotographic apparatus is fixed to a metal plate which is common to the power supply board for supplying the power source so as to make the earth common and enlarge the earth area. Moreover, the power supply board is housed in a box-shaped sheet metal. In addition, in order to maintain mechanical accuracy and to avoid the influence of heat, the optical system unit generally protects the unit body with a metal cover.

That is, the control board has a CPU for controlling the operation of the electrophotographic apparatus, and in the case of a printer, the image data sent from a personal computer or the like is expanded in a memory, and the expansion result is sequentially used as a light source for exposure. In addition to sending and modulating it, control is performed to form an image on the image bearing member with the modulated light.In addition to this, instructions for starting and stopping development, instructions for applying developing bias for development, etc. It is done from the board.

Therefore, the malfunction of the control board may hinder the normal operation of the apparatus. On the other hand, in the electrophotographic apparatus, a DC bias of 400V to 500V and a peak _-to- peak voltage _Vp-p are applied to the electrophotographic apparatus. Various high voltages such as an AC bias of about 1.2 KV are used, and unless the control board is shielded from the noise generated by these high voltages, it causes malfunction.

That is, fixing the control board to the sheet metal common to the power supply board to standardize the ground and expand the ground area is because these noise sources are in the same device, and control is performed from these influences. This is because the substrate is protected and the housing of the electrophotographic apparatus is made of a non-conductive material as described above, so that the housing cannot be used as a common ground.

[0009]

However, in this case, due to the restriction that the power supply board and the control board are mounted on the same sheet metal, the degree of freedom in the layout of the main body structure and the storage space of the board is reduced, which affects the miniaturization of the device. The problem of giving. On the contrary, if the power supply board and the control board are separately installed, it becomes difficult to make the ground common, and it becomes difficult to secure the ground area, which makes it difficult to shield from noise.

Therefore, in the present invention, an electrophotographic apparatus is provided in which the power supply board and the control board can be separately arranged while satisfying the point of shielding the control board from noise, and the size of the apparatus can be reduced. Is to provide.

[0011]

In order to solve the above-mentioned problems, according to the present invention, a control board for controlling the operation of the electrophotographic apparatus, a power supply board for supplying power, and an image on an image carrier of the electrophotographic apparatus. an optical system unit for imaging in a metal cover member for the optical unit, in an electrophotographic apparatus having a housing by resin molding, the control board and the front
The power supply boards are arranged on different surfaces with the paper conveyance path formed in the housing interposed therebetween, and the front surface is provided between the surfaces.
The metal cover member is installed, and the metal cover member is interposed.
The control board and the power board are commonly grounded.

With this configuration, the degree of freedom in the arrangement of the power supply board and the control board is increased, the size of the electrophotographic apparatus can be reduced, and the boards are installed between the surfaces on which the boards are arranged. By using the metal cover member of the optical system unit as a common ground, a large ground area can be obtained, and the device can be reinforced, so that it is possible to provide a compact electrophotographic device that is resistant to noises.

[0013] Then, the control board in order to prevent malfunctions due to noise, characterized by being arranged to accommodate the control board to the shield box having a shielding effect from noise.

By doing so, the control board for controlling the operation of the electrophotographic apparatus can be securely shielded from noise, and an electrophotographic apparatus without malfunction can be provided. Also,
At least the image bearing is provided on the surface side on which the control board is provided.
Motor control board that controls the main motor that drives the holder
May be provided, and the power supply board is not provided.
On the upper surface side of the power supply board,
A fan may be provided.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be exemplarily described in detail below 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 thereto unless otherwise specified, and are merely descriptions. It's just an example.

First, the outline of the present invention will be described. In the present invention, the power supply board and the control board are arranged on different surfaces of the housing of the electrophotographic apparatus, and the metal cover of the optical system unit is arranged between the surfaces on which the boards are arranged. The member is erected, and the metal cover member is used as a common ground and also serves as a reinforcement of the device.

With this configuration, the degree of freedom in the arrangement of the power supply board and the control board is increased, the size of the electrophotographic apparatus can be reduced, and the boards are installed between the surfaces on which the boards are arranged. By using the metal cover member of the optical system unit as a common ground, a large ground area can be obtained, and the device can be reinforced, so that it is possible to provide a compact electrophotographic device that is resistant to noises.

FIG. 1 is an external perspective view of an apparatus to which the present invention is applied, FIG. 2 is a perspective view showing a mounting state of a control board with the right side cover of FIG. 1 removed, and FIG. FIG. 4 is a perspective view showing a mounting state of the power supply board with the left side cover removed, and FIG. 4 is a rear view of the mounting state of the metal cover member of the optical system unit with the top cover removed. In the following description, a printer will be described as an example, but the present invention is not limited to a printer, but can be applied to a copying apparatus, a fax machine, or any other apparatus that performs an electrophotographic printing operation.

In the figure, 1 is a printer to which the present invention is applied, 2 is a control board for controlling the operation of the printer 1, 3 is a motor control board, and 4 is a metal having a shield effect for protecting the control board 2 from noise. A shield box made of a material or the like, 5 is a ground terminal of the shield box 4, 6 is a power supply board for supplying stabilized power to the apparatus, 7 is a ground board of the power supply board 6, 8 is a high voltage board, and 9 is an optical system unit. The metal cover member 10 is a main motor for driving the image carrier of the electrophotographic apparatus and the recording medium conveying device, and 11 is a fan for forced cooling.

The control board 2 has a CPU for controlling the operation of the electrophotographic apparatus as described above, and in the case of a printer, expands image data sent from a personal computer or the like in a memory and sequentially exposes the expansion result. To the light source for modulation and modulates it, and controls the formation of an image on the image carrier with the modulated light. In addition to this, commands to start and stop development, and apply a development bias for development. Instructions are given from this board.

The power supply board 6 is a board for supplying power required for each unit of the electrophotographic apparatus such as the control board 2, a fixing heater (not shown), the motor 10 and the like. As shown in FIG. 3, it is attached near the fan 11 so that forced cooling can be performed.

The motor control board 3 in FIG. 2 is a board for controlling the main motor 10 for driving the image carrier and the recording medium conveying device, and the high-voltage board 8 in FIG. 3 is the image carrier and the toner carrier during development. It is a substrate that generates a DC bias of 400V to 500V to be applied to the body as described above. As described above, since an AC bias is also applied during development, a bias substrate (not shown) or the like is attached.

As described above, in the electrophotographic apparatus, the control board 3 of the motor, which is a noise source, the high-voltage board 8 for generating high voltage and high frequency, the bias board, etc. are installed in the immediate vicinity of the control board 2. The malfunction of the CPU due to noise directly impedes the operation of the electrophotographic apparatus.

Therefore, in the present invention, as shown in FIG. 2, the control board 2 is covered with a shield box 4 made of a conductive material such as metal, and the metal portion contacts the ground portion of the control board 2. As described above, the ground terminal 5 is attached to one side surface of the housing and is provided on the upper end side of the shield box 4 together with the metal cover member 9 of the optical system unit on the upper end side of the device as shown in FIG. Be able to screw.

As shown in FIG. 3, the power supply board 6 has a fan 1 on one side of the housing of the apparatus, which is different from the control board 2.
Attach it close to 1 and screw the ground plate 7 to the ground part. Then, the other end of the ground plate 7 is extended to the upper end side of the apparatus as shown in FIG. 4 so that it can be screwed together with the metal cover member 9 of the optical system unit.

On the upper ends of both side surfaces, the metal cover member 9 of the optical system unit is placed from above as shown in FIG. 4, and the ground terminal 5 on the upper end of the shield box 4 of the control board 2 and the power supply board. Screw together with the ground plate 7 of 6.

By doing so, the noise generated in the device as described above is shielded by the shield box 4 of the control board 2 and the metal cover member 9 of the optical system unit at the ground common to the power supply board 6. Control board 2
It is possible to prevent a large influence on the internal CPU and the like. Further, since the metal cover member 9 of the optical system unit ties the side surface of the device to reinforce the device itself, a durable device can be provided.

[0028]

As described above , according to the present invention, the degree of freedom in the arrangement of the power supply board and the control board is increased, the size of the electrophotographic apparatus can be reduced, and the surface on which the respective boards are arranged can be reduced. By using the metal cover member of the optical system unit installed between them as a common ground, a large ground area can be obtained, and the frame strength can be reinforced, so that it is possible to provide a compact electrophotographic apparatus that is small in size and resistant to noise. .
Also, since the structure is simple, assembly and maintenance are dramatically improved.

[0029] According to or present invention, can be tightly shield the control board for controlling the operation of the electrophotographic apparatus from the noise, it is possible to provide an electrophotographic apparatus having no malfunction.

[Brief description of drawings]

FIG. 1 is an external perspective view of an apparatus to which the present invention is applied.

FIG. 2 is a perspective view showing a mounting state of a control board with the right side cover of FIG. 1 removed.

FIG. 3 is a perspective view showing a mounting state of a power supply substrate with the left side cover of FIG. 1 removed.

FIG. 4 is a rear perspective view of the optical system unit with the metal cover attached, with the top cover of FIG. 1 removed.

[Explanation of symbols]

1 Printer device 2 control board 3 Motor control board 4 shield box 5 ground terminal 6 power board 7 ground plate 8 high-voltage board 9 Metal cover member for optical system unit 10 Main motor 11 fans 12 Paper transport path

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-10-86481 (JP, A) JP-A-6-115217 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 15/00 550 G03G 21/16-21/18 B41J 29/00-29/70

Claims (4)

(57) [Claims] 1. A control board for controlling the operation of the electrophotographic apparatus, a power supply board for supplying power, an optical system unit for forming an image on an image carrier of the electrophotographic apparatus, and a metal of the optical system unit. and the cover member, in an electrophotographic apparatus having a housing by resin molding, forming the power supply board and the control board in said housing
They are placed on different surfaces across the paper transport path.
The metal cover member between the surfaces ,
An electrophotographic apparatus, wherein the control board and the power supply board have a common ground via a cover member . 2. The electrophotographic apparatus according to claim 1, wherein the control board is housed and disposed in a shield box having a noise shielding effect. 3. The surface side on which the control board is disposed has a small amount of
Control at least the main motor that drives the image carrier
The motor control board is provided, according to claim 2,
The described electrophotographic apparatus. 4. The surface side on which the power supply board is disposed
A fan for forced cooling is installed above the power board.
The electrophotographic photograph according to claim 1, wherein
apparatus.