JPH022000A - Electromagnetic shielding structure of electronic device case - Google Patents

Abstract

PURPOSE:To decrease a manufacturing cost by a method wherein the tip of a pin-like conductive member of a shielding means is brought into contact with a case when a lid is closed, and a gap of a joining section of the case with the lid is electromagnetically sealed. CONSTITUTION:As electromagnetic wave, radiated from various devices inside an apparatus in operation, leaks outside from the junction of a lid or a door to affect adjacent apparatus, a shielding means 40 formed into a brush shape is fitted to the junction (four sides including a bearing side C) of a case 30 with a lid 34 and the junction (same as above, four sides including a bearing side D) of the lid with a door 38. Thereby, when the lid or the door is closed, each junction is electromagnetically shielded, so that the outward radiation of an electromagnetic wave and the penetration of the electromagnetic wave from the outside can be prevented. The brush-like shielding means is constituted in such a manner that a face of an end of two or more conductive pin-like members is bonded to an aluminum tape 44 provided with an adhesive agent and the other face is joined to one side of a both side tape 46, and the other side of the tape 46 is pasted to the junction of the lid or the door.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electromagnetic wave shielding structure for a housing for an electronic computer, an image recording/forming/reading/transmission device, or other electronic devices.

Conventional Technology For example, in a printer device using electrophotographic technology, an electrostatic latent image corresponding to image data to be printed is formed by exposing the negatively charged surface of a photoreceptor drum to light, and this electrostatic latent image is After developing with toner or the like, the image is transferred onto paper and fixed by heat or the like to obtain a desired image.

In order to perform the above-mentioned processing, such an image recording apparatus is equipped with a charging corotron, a laser head, a transfer corotron, etc. around the photoreceptor drum, and is also equipped with a paper transport device, a control device, a power supply device, etc. For example, various electromagnetic waves are emitted by corona discharge from a corotron, laser light oscillation, or from a control device, power supply device, motor, etc.

For example, this electromagnetic wave may be used to interfere with a nearby TV or radio, disrupting the TV image, or generating noise, or electromagnetic waves generated by other devices installed nearby. Since electromagnetic waves may malfunction due to the influence of electromagnetic waves, it is necessary to shield electromagnetic waves from leaking to the outside of the device or from entering the device.

In order to completely shield the device, it is ideal to completely cover the device with a material that has a shielding effect, such as metal. However, for maintenance such as replacing consumables and removing jammed paper, the device It is necessary to attach a door or a lid that can be opened and closed to the housing that houses the equipment.

This creates a gap at the joint between the housing and the door or lid, making the shielding incomplete. Therefore, a stick finger 10 made of beryllium copper as shown in FIG. A carbon rubber 12 made of carbon-containing silicone rubber or the like is attached to the joint between the box 14 and the lid 16, as shown in FIG. 13, and when the lid 16 is closed, the box 14 The gap between the joint and the lid 16 is electromagnetically sealed to shield electromagnetic waves. (Staink finger and carbon rubber are trade names of Kitagawa Kogyo Co., Ltd.) Problems to be solved by the invention However, the stick finger described above costs about 2,000 yen per meter; It is expensive, and there are problems in terms of cost, as well as structural problems, such as requiring high precision in the positional relationship between the box and the lid and in the joints.

The present invention has been made in view of these points, and an object of the present invention is to provide an electromagnetic wave shielding structure for an electronic device housing that can reduce manufacturing costs.

Means for Solving the Problems FIGS. 1 to 3 are detailed explanatory diagrams of the present invention. 20
2 is a shielding means in which a plurality of acicular conductive members 22 are arranged side by side, and one end side of the plurality of acicular conductive members 22 is fixed by a fixing member 24 to form a brush shape (FIGS. 2 and 3). reference).

26 is a box constituting the electronic device housing, and 28 is a lid provided on the box 26 so as to be openable and closable. When the fixing member 24 side of the plan-shaped shielding means 20 is attached to the joint part of the lid body 28 with the box body 26 and the lid body 28 is closed, the tip of the needle-like conductive member 22 of the shielding means 20 is attached to the box body 26. It is configured to contact the body 26 and electromagnetically seal the gap between the joint between the box body 26 and the lid body 28 (see FIG. 1).

In addition, the brush-shaped shielding means 20 is not the lid body 28 but the box body 26.
It may be installed on.

FIG. 4 and FIG. 5 are diagrams showing the results of measurement of leakage electromagnetic waves by the present inventors using an electrophotographic printer device. FIG. 5 shows the measurement results of a housing having an electromagnetic wave shielding structure according to the present invention. The measurement method was conducted in accordance with the regulations of the International Special Committee on Radio Interference.

The vertical axis is gain (dB), and the horizontal axis is frequency (MHz). In the figure, dotted line A is the regulation value set by the above committee, and dotted line B is the regulation value set by the inventors.

In the case without shielding measures (Fig. 4), the regulation value is exceeded at around 100 MHz, so it is recognized that it is necessary to take shielding measures for this case. When the structure of the present invention is applied to this casing (FIG. 5), the gain of the leakage electromagnetic waves decreases overall, and the gain decreases significantly in the vicinity of 150 MHz, which is significantly below the regulation value.

For reference, FIG. 6 shows similar measurement results for a casing using stick fingers, and FIG. 7 shows similar measurement results for a casing using carbon rubber. It can be seen that the casing according to the present invention has substantially the same shielding effect as these.

As described above, the casing configured by applying the present invention can obtain a shielding effect equivalent to that of a casing using stick fingers or carbon rubber, and furthermore, the casing configured by applying the present invention can obtain the same shielding effect as the casing using stick fingers or carbon rubber. The cost is about 400 yen per meter, which makes it possible to provide an inexpensive housing.

In addition, as can be seen from Figure 1, the tip of the needle-like member of the shielding means is elastically deformed and comes into contact with the box or lid, and electromagnetically seals it. It is not necessary to have very strict precision in the relative position of the lid body and the lid body, and from this point of view as well, cost reduction can be achieved.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 8 is an external perspective view of an electrophotographic printer using a casing to which the structure of the present invention is applied.

This printer device is mainly equipped with a photosensitive drum, a charging device, an exposure device, a developing device, a transfer device, etc., and is also composed of a fixing device, a recording paper transport device, a power supply device, a control device, etc. .

To explain the outline of the internal processing, the surface of the photoreceptor drum is uniformly charged by a charging device, and an electrostatic latent image is formed according to the image data to be printed by an exposure device such as an LED head or a laser head. , this electrostatic latent image is developed with toner by a developing device.

On the other hand, the recording paper is stored in a drawable tray 32 on the side of the box body 30.
The recording paper is conveyed by a conveyance device in synchronization with the rotation of the photoreceptor drum, the toner image is transferred onto the recording paper by a transfer device, and then fixed by a fixing device, and the toner image is fixed on the cover body. The paper is discharged onto a discharge tray 36 provided on the 34 side.

FIG. 9 is a perspective view of FIG. 8 seen from the rear.

The lid 34 is rotatably supported by the box 30 in six parts, and by opening the lid 34, you can replace the photosensitive drum,
It is now possible to perform maintenance such as removing jammed recording paper. Further, a door 38 is provided on the back side of the lid body 34 so as to be openable and closable for maintenance and the like. , 38a is a vent formed in the door 38, 3
8b is a handle for opening and closing the door 38.

In this way, for maintenance of the various devices installed inside, the housing is configured with a lid and door that can be opened and closed, and therefore, radiation from the various devices inside the device is emitted during operation. Since the electromagnetic waves leak out from the joints of the lid and door and affect adjacent devices (for example, disturbing the TV image), a brush-shaped shielding means 40 is used.
Joint part between box body 30 and lid body 34 (four sides including support side C)
It is also attached to the joint between the lid 34 and the door 38 (four sides including the support side).

Thereby, when the lid or the door is closed, each joint is electromagnetically shielded, and it is possible to prevent electromagnetic waves from being radiated to the outside and from entering from the outside.

As shown in FIG. 1O, the brush-like shielding means used in this example is such that one end side of a plurality of conductive needle-like members 42 is covered with adhesive-coated aluminum 44, and the other side is covered with double-sided tape. The structure is such that one side of the double-sided tape 46 is adhered, and the other side of the double-sided tape 46 is attached to the joint of the lid or door.The cost is about 400 yen per meter, and it is much more effective than conventional shielding means. It is inexpensive.

Effects of the Invention As described in detail above, the present invention attaches a brush-shaped shielding means to each joint of a housing configured with an openable lid or door, thereby reducing the gap when the lid or door is closed. Electromagnetically sealed, the shielding means are inexpensive, and high precision is not required for mounting the lid or door, etc., providing a housing for electronic devices with low manufacturing costs and high shielding effect. It has the effect of being able to do it.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the basic structure of the present invention, Fig. 2 is a plan view of the brush-like shielding means used in the present invention, Fig. 3 is a side view of Fig. 2, and Fig. 4 shows no shielding measures taken. Figure 5 shows the electromagnetic wave measurement results of the housing to which the structure of the present invention is applied. Figures 6 and 7 show the electromagnetic wave measurements of the housing with conventional shielding measures. Figures 8 and 9 are front and rear perspective views for explaining an embodiment of the present invention, and Figure 10 is a diagram showing the brush-like shielding means used in an embodiment of the present invention. The perspective view and FIGS. 11 to 13 are explanatory diagrams of the prior art. 0... Brush-like shielding means, 2... Needle-shaped member, 4... Fixing member, 6... Box body, 8... Lid body. Applicant: Fuji Xerox Co., Ltd.

Claims (1)

[Scope of Claims] In a housing for an electronic device in which a box body is provided with a cover that can be opened and closed, a plurality of needle-like conductive members are arranged in parallel, and one end side of the plurality of needle-like conductive members is fixed. to form a brush-like shielding means, and attach the shielding means to either one of the joints between the box body and the lid body, so that when the lid body is closed, the tip of the acicular conductive member of the shielding means is connected to the box body. 1. An electromagnetic wave shielding structure for an electronic device housing, characterized in that the body and the lid come into contact with the other side to which the shielding means is not attached to prevent leakage of electromagnetic waves.