JP2611335B2 - Electromagnetic wave shielding structure of electronic device housing - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave shielding structure of an electronic computer, an image recording / forming / reading / transmitting device, and a housing for other electronic devices.

2. Description of the Related Art For example, in a printer device using an electrophotographic technique, a uniformly charged photosensitive drum surface is exposed to form an electrostatic latent image corresponding to image data to be printed, and this electrostatic latent image is formed. Is developed with toner or the like, and then transferred to a sheet, which is fixed by heat or the like to obtain a desired image.

In such an image recording apparatus, a charging corotron, a laser head, a transfer corotron and the like are provided around the photosensitive drum in order to perform the above-described processing, and other components such as a paper transport device, a control device, and a power supply device are provided. A device is provided, for example, by corona discharge or laser light oscillation by a corotron, or a control device, a power supply device,
Various electromagnetic waves are emitted from a motor or the like.

This electromagnetic wave interferes with, for example, a nearby TV or radio, etc., to disturb the TV image or generate noise, or to generate electromagnetic waves generated by another device adjacent to the TV. May malfunction due to the influence of
Leakage of electromagnetic waves to the outside of the device or entry into the inside must be shielded.

In order to completely perform this shielding, it is ideally desirable to completely cover the apparatus with a member having a shielding effect such as metal. However, the apparatus is required for maintenance such as replacement of consumables and removal of jammed paper. It is necessary to attach and open a door or a lid that can be opened and closed to the housing that stores the.

As a result, a gap is formed at the joint between the housing and the door or the lid, and the shielding is incomplete.Therefore, the stick finger 10 made of beryllium copper as shown in FIG. 11, or as shown in FIG. As shown in FIG. 13, carbon rubber 12 made of silicon rubber or the like containing carbon,
Affixed to the junction between the box 14 and the lid 16 and when the lid 16 is closed, the gap between the junction between the box 14 and the lid 16 is electromagnetically sealed to shield electromagnetic waves. I was (Stick finger and carbon rubber are trade names of Kitagawa Industry Co., Ltd.) Problems to be Solved by the Invention However, the above-mentioned stick finger costs about 2,000 yen per meter and about 700 yen per meter of carbon rubber. In addition to being expensive and having a problem in terms of cost, there is also a problem in terms of structure that high precision is required in the positional relationship between the box and the lid and in the joint.

The present invention has been made in view of such a point,
An object of the present invention is to provide an electromagnetic wave shielding structure of an electronic device housing that can reduce manufacturing costs.

Means for Solving the Problems FIGS. 1 to 3 are explanatory diagrams of the principle configuration of the present invention.
Reference numeral 20 denotes a shielding means in which a plurality of needle-shaped conductive members 22 are arranged in parallel, and one end side of each of the plurality of needle-shaped conductive members 22 is fixed by a fixing member 24 to form a brush (see FIGS. 2 and 3). See figure).

Reference numeral 26 denotes a box constituting the housing of the electronic device, and reference numeral 28 denotes a lid provided on the box 26 so as to be openable and closable. The fixing member 24 side of the brush-shaped shielding means 20 is attached to the joint of the lid 28 and the box 26,
When the lid 28 is closed, the tip of the needle-shaped conductive member 22 of the shielding means 20 comes into contact with the box 26 so as to electromagnetically seal the gap between the joint of the box 26 and the lid 28. (See FIG. 1).

The brush-shaped shielding means 20 may be attached to the box 26 instead of the lid 28.

Operation FIGS. 4 and 5 are diagrams showing the results of measurement of leakage electromagnetic waves by the present inventors using an electrophotographic printer, and FIG. The figure shows a measurement result of a casing having an electromagnetic wave shielding structure according to the present invention.
The measurement was performed in accordance with the rules of the International Commission on Radio Interference.

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

In the case where there is no shielding measure (FIG. 4), the regulation value is exceeded in the vicinity of 150 MHz. When the structure of the present invention is applied to this housing (FIG. 5), the gain of the leaked electromagnetic wave is reduced as a whole, and the gain is significantly reduced around 150 MHz, which is much lower than the regulation value.

For reference, FIG. 6 shows a similar measurement result of a case using a stick finger, and FIG. 7 shows a similar measurement result of a case using a carbon rubber. It can be seen that the casing according to the present invention has almost the same shielding effect.

As described above, the housing configured by applying the present invention can obtain the same shielding effect as the housing using the stick finger or the carbon rubber, and furthermore, the brush-shaped shielding means used in the present invention. Is about four hundred yen per meter, so that an inexpensive housing can be provided.

Also, as can be seen from FIG. 1, the tip of the needle-shaped member of the shielding means is elastically deformed and comes into contact with the box or the lid,
Since it is electromagnetically sealed, the relative position between the box and the cover when the cover is closed does not require strict accuracy, and the cost can be reduced from this point as well.

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 housing to which the structure of the present invention is applied. This printer device includes a photoconductor drum, a charging device, an exposure device,
A developing device, a transfer device, and the like are provided.
It comprises a recording paper transport device, a power supply device, a control device and the like.

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

On the other hand, recording paper is stacked and placed on a tray 32 which can be pulled out of the box 30 side. This recording paper is sent in synchronization with the rotation of the photosensitive drum by the transport device, and the toner is transferred onto the recording paper by the transfer device. The image is transferred, then fixed by a fixing device, and discharged onto a discharge tray 36 provided on the foot of the lid 34.

FIG. 9 is a perspective view of FIG. 8 as viewed from the rear. The cover 34 is rotatably supported by the box 30 at the portion C, and by opening the cover 34, maintenance such as replacement of the photosensitive drum and removal of jammed recording paper can be performed. It has become. Further, a door 38 is provided on the rear surface of the lid 34 so as to be openable and closable for maintenance and the like. 38a is a vent formed in the door 38, and 38b is a handle for opening and closing the door 38.

Thus, for maintenance of various devices provided inside, the housing is configured to be provided with an openable / closable lid and a door, and therefore, is radiated by various devices inside the device during operation. Electromagnetic wave leaks out of the joint of the lid and the door and affects adjacent devices (for example, disturbs TV images).
30 and lid 34 and joint (4 sides including bearing side C) and lid 34
And the door 38 (also on the four sides including the bearing side D).

Thereby, when the lid or the door is closed, each joint is electromagnetically shielded, so that the radiation of electromagnetic waves to the outside and the entry of electromagnetic waves from the outside can be prevented.

As shown in FIG. 10, the brush-like shielding means used in the present embodiment has a plurality of conductive needle-shaped members 42 on one end side with an adhesive-applied aluminum tape 44 and the other side with a double-sided surface. Adhesive is applied on one side of the tape 46 and the other side of the double-sided tape 46 is attached to the joint of the lid or the door.
It costs about 400 yen per meter and is much cheaper than conventional shielding means.

Effect of the Invention As described in detail above, the present invention attaches a brush-like shielding means to each joint of a housing provided with an openable and closable lid and a door, and thereby a gap when the lid and the door are closed. Is electromagnetically sealed, the shielding means is inexpensive, a high precision is not required for attaching the lid or the door, the manufacturing cost is low, and a housing of the electronic device with a high shielding effect can be provided. This has the effect.

[Brief description of the drawings]

1 is a diagram showing the principle of the present invention, FIG. 2 is a plan view of a brush-like shielding means used in the present invention, FIG. 3 is a side view of FIG. 2, and FIG. FIG. 5 shows the results of electromagnetic wave measurement of the housing, FIG. 5 shows the results of electromagnetic wave measurement of the housing to which the structure of the present invention is applied, and FIGS. 6 and 7 show the electromagnetic wave measurement of the housing with conventional shielding measures. FIG. 8 and FIG. 9 are front perspective views and rear perspective views for explaining one embodiment of the present invention. FIG. 10 is a view showing a brush-like shielding means used in one embodiment of the present invention. FIG. 11 is a perspective view, and FIG. 11 to FIG. 20: brush-shaped shielding means, 22: needle-like member, 24: fixing member, 26: box, 28: lid.

Claims (1)

(57) [Claims] 1. A housing for an electronic device comprising a box body provided with an openable and closable lid, a plurality of needle-like conductive members arranged in parallel, and one end side of the plurality of needle-like conductive members is provided with an adhesive. With the conductive tape and the double-sided tape sandwiched together by one of the adhesive surfaces to form a brush-like shielding means, the shielding means at one of the joints of the box and the lid, It is attached by bonding with the other adhesive surface of the double-sided tape, so that when the lid is closed, the tip of the needle-shaped conductive member of the shielding means contacts the other of the box and the lid where the shielding means is not attached. An electromagnetic wave shielding structure for an electronic device housing, characterized in that: