| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to attenuate an electromagnetic wave by means of a low-cost and simple technique, furthermore with a small variation by only a screw setting between a flange and a lid of a case. SOLUTION: When an electrical substrate for controlling an image forming apparatus is fixed at a case 320 and an upper flange 331 and a lower flange portion 332 of a lid 330 by a screw 340, by setting a pitch spacing of a screw as (a), a width dimension of the flange portion as (z) and an attenuation amount of a necessary electromagnetic wave as r (dB), values of (a), (z) are decided so that the attenuation amount (r) may satisfy an experiment formula that the attenuation amount (r) is almost proportional to the value (z) and is almost inversely proportional to the value (a). COPYRIGHT: (C)2007,JPO&INPIT
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