JP4223229B2

JP4223229B2 - Electronic apparatus mounting method, electronic apparatus mounting apparatus, and image reading apparatus

Info

Publication number: JP4223229B2
Application number: JP2002139367A
Authority: JP
Inventors: 健金井
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 2002-05-15
Filing date: 2002-05-15
Publication date: 2009-02-12
Anticipated expiration: 2022-05-15
Also published as: JP2003332787A

Description

【０００１】
【発明の属する技術分野】
この発明は、各種電子機器等を筐体に取付ける電子機器取付方法と電子機器取付装置及び画像読取装置、特に外部へ漏洩する電磁波ノイズの低減に関するものである。
【０００２】
【従来の技術】
近年、電子機器の高機能化と高クロック化に伴い電子機器から発生する電磁波による障害が問題となってきている。特に複写機などの画像読取部においては高画質化のためにクロック数が高くなっており、漏洩する電磁波ノイズの各部への影響がさらに問題となってきている。この問題に対応するため、例えば特開平５−１９９３４０号公報に示すように、画像読取部と画像書込部及び画像信号を補正処理する１次信号処理部などの電子部品からなる電子機器部分を、接地された導電性の筐体の内部に収納して電磁シールドを図り、筐体外部へ漏洩する電磁波ノイズを低減するようにしている。
【０００３】
【発明が解決しようとする課題】
しかしながら複写機等の各部における作動クロックの周波数が高くなってくると、電子機器が取り付けられる筐体自身が発振するという問題が生じ、筐体を接地して電磁シールドをしても電磁波障害に対処する根本的な解決にはならないという短所がある。
【０００４】
特に複写機等の画像形成装置においては、画像読取部の筐体には高周波数の作動クロックの読取装置と信号処理部が設置される上、構造的に画像読取部の上面に読取対象の原稿がセットされるコンタクトガラスが嵌め込まれる開口部が形成されるため、この開口部の存在により筐体全体を完全に電磁シールドすることは困難であり、電磁波ノイズの漏洩が生じ易い。
【０００５】
この発明はかかる短所を改善し、電子機器が搭載される筐体寸法で決まる共振周波数の電磁界分布と筐体を振動させる電子機器の位置関係に着目し、簡単な構成で電磁波ノイズの低減化を図ることができる電子機器取付方法と電子機器取付装置及び画像読取装置を提供することを目的とするものである。
【０００６】
【課題を解決するための手段】
この発明に係る電子機器取付方法は、外部に通じる隙間や開口を有する筐体の内部に設置される電子機器にて生じる電磁妨害波を低減させる電子機器取付方法であって、電子機器が取り付けられる筐体の寸法情報を入力する工程と、入力した筐体の寸法データにより筐体における複数の共振周波数で周回する磁界分布のベクトルを演算する工程と、電子機器から放射される周波数毎に主要な磁界放射の磁界強度を計測する工程と、演算した筐体における複数の共振周波数で周回する磁界分布のベクトルと計測した電子機器から放射される周波数毎の主要な磁界放射の磁界強度とに基づき、電子機器から放射される磁界放射の磁界強度が最も高い周波数で周回する磁界分布の中心部分を電子機器の取付位置に設定する工程と、設定した取付位置に電子機器を配置する工程とを有することを特徴とする。
【０００７】
この発明の電子機器取付装置は、外部に通じる隙間や開口を有する筐体の内部に設置される電子機器にて生じる電磁妨害波を低減させる電子機器取付装置であって、チャッキング手段と駆動手段と入力手段と演算手段と計測手段及び制御手段を有し、チャッキング手段は前記電子機器を保持し、駆動手段はチャッキング手段を移動させて位置決めし、入力手段は電子機器が取り付けられる筐体の寸法情報を入力し、演算手段は入力手段で入力した筐体の寸法データにより筐体における複数の共振周波数で周回する磁界分布のベクトルを演算し、計測手段は電子機器から放射される周波数毎に主要な磁界放射の磁界強度を計測し、制御手段は演算手段の演算結果と計測手段の計測結果とに基づき、計測手段で計測された電子機器から放射される磁界放射の磁界強度が最も高い周波数で周回する磁界分布の中心部分を電子機器の取付位置に設定し、駆動手段を駆動させてチャッキング手段で保持した電子機器を設定した取付位置に配置することを特徴とする。
【０００９】
この発明の画像読取装置は、原稿が載置されるコンタクトガラスの設置側に開口を有する筐体と、該筐体の内部に設けられ、コンタクトガラスに載置された原稿の情報を読み取る光学系と、該光学系で読み取った光学情報を電気的情報に変換する信号処理手段とを有する画像読取装置において、筐体の寸法データにより筐体における複数の共振周波数で周回する磁界分布のベクトルを演算し、信号処理手段から放射される周波数毎に主要な磁界放射の磁界強度を計測し、演算した筐体における複数の共振周波数で周回する磁界分布のベクトルと計測した信号処理手段から放射される周波数毎の主要な磁界放射の磁界強度とに基づき、信号処理手段から放射される磁界放射の磁界強度が最も高い周波数で周回する磁界分布の中心部分を信号処理手段の取付位置に設定し、設定した取付位置に信号処理手段を配置したことを特徴とする。
【００１０】
【発明の実施の形態】
図１は複写機の概要を示す構成図である。図に示すように、複写機１は原稿読取部２と画像形成部３と給紙装置４を有する。原稿読取部２は装置本体の上部に形成された開口部５に設けられ、原稿が載置されるコンタクトガラス６と、コンタクトガラス６の設置側に開口部５が形成された筐体７の内部に設けられた光学系８と信号処理系９とを有する。光学系８はコンタクトガラス６に載置された原稿を照明する光源１０と、原稿からの反射光を偏向させる複数の反射ミラー群１１と結像レンズ１２などから構成され、信号処理系９は結像レンズ１２にて結像する原稿画像を受光して光電変換する光電変換素子１３と、光電変換素子１３から画像情報を受けて各種信号処理を行う電子部品やユニットなどの電子機器からなる信号処理部１４と、信号処理部１４が実装される回路基板１５などから構成されている。
【００１１】
画像形成部３は、信号処理部１４からの制御信号を受けて発光制御されるレーザ光源から出射されるレーザ光を偏向させるポリゴンミラー１６と、ポリゴンミラー１６で偏向されたレーザ光により走査／露光される感光体１７と、感光体１７の周囲に配置される帯電チャージャ１８と現像部１９と転写チャージャ２０などからなる電子写真プロセス部２１と定着部２２などで構成されている。この画像形成部３の下部には給紙装置４が配置されている。給紙装置３は記録紙を収納する給紙カセット２３と搬送ローラ２４と排紙ローラ２５などからなり、給紙カセット２３から給紙された記録紙は、画像形成部３の感光体１７に形成されたトナー像が転写チャージャ２０で転写され、トナー像が転写された記録紙は定着部２２で加熱加圧されて定着され、排紙ローラ２５により外部に排出される。
【００１２】
この複写機１において、原稿読取部３は、一部に開口部５が形成された筐体７の内部に光電変換素子１３と信号処理部１４と回路基板１５を有する信号処理系９が設けられており、特に信号処理部１４には各種の電子部品やユニットなどの電子機器から構成されているため、作動時に電磁波ノイズである磁界ノイズが発生する。この信号処理部１４を構成する電子機器２６と開口部５を有する筐体７の位置関係を図２の模式図に示す。この筐体７のＸ，Ｙ，Ｚ方向の長さをそれぞれａ，ｂ，ｃとして電磁波の速さをｖとすると、筐体７の共振周波数ｆは下記（１）式で表せる。
【００１３】
【数１】

【００１４】
上記式において、ｍ，ｎ，ｑはそれぞれＸ，Ｙ，Ｚ方向の磁界パターンの数を示す。ここで例えば筐体７の外形寸法を、ａ＝0.5ｍ、ｂ＝0.4ｍ、ｃ＝0.05ｍとすると、共振周波数ｆは下記表に示すようになる。
【００１５】
【表１】

【００１６】
この（ａ）〜（ｆ）の各共振周波数480ＭＨｚ〜1644ＭＨｚに対応する磁界パターンは図３の（ａ）〜（ｆ）に示すものになる。図３は筐体７をＺ軸上方から見て周回する磁界分布２７を示す。
【００１７】
一方、信号処理部１４を構成する電子機器２６から放射される磁界の周波数成分ごとの強度を、図４に示すように、ループアンテナ３０とスペクトラムアナライザ３１を使用して計測した結果を図５に示す。図５に示すように、周波数が970ＭＨｚで磁界ノイズが最も高いことが分かる。この周波数970ＭＨｚにおける筐体７の磁界分布は図３の（ｃ）で示される。これらのことから、周波数970ＭＨｚにおける磁界ノイズを低減するには、図３（ｃ）に示す周回磁界分布２７の中心部分に電子機器２６を配置することによって、電子機器２６から放射される磁界ノイズを低減させることができる。
【００１８】
これを数値シミュレーションにより検証した結果を示す。この検証は、図６に示すように開口部５を有する筐体７に内蔵されるノイズ源である電子機器２６を有する信号処理部１４の回路基板１５の位置を変えた場合における電磁界伝播挙動を有限差分時間領域法によるシミュレーションを行って評価した。この解析では解析空間を格子状に分割して、マクスウェル方程式を差分して時間領域で解く。具体的には入力点である回路基板１５の入力端にパルスを入力し、かつ出力に対して波形をフーリエ変換することにより周波数領域での情報を得ることができる。また、回路基板１５には線路１５ａがある。ここで筐体７の各寸法を、ａ＝0.5ｍ、ｂ＝0.4ｍ、ｃ＝0.05ｍとすると、前記（１）式からｍ＝３、ｎ＝１、ｑ＝０における共振周波数ｆは９７４ＭＨｚである。ここで図６において、回路基板１５の端部と筐体７のＸ方向の距離をｅとし、ｅ＝0.23ｍで回路基板１５を筐体７の中心に配置したケース１の場合と、比較例としてｅ＝0.01ｍの位置に回路基板１５を配置したケース２の場合における電磁界伝播挙動を開口部５の直上の電界から計算して各周波数における電界強度の伝播特性を図７に示す。図７に示すように、開口部５が開いているため、共振周波数ｆが974ＭＨｚから1015ＭＨｚへシフトしているが、ケース１の場合はケース２の場合と比べて磁界強度が１／２以下になっていることが分かる。このケース２の周波数1015ＭＨｚでの磁界強度分布を図８に示す。図８は磁界強度における1.0Ｅ−01Ａ／ｍを０ｄＢとした場合の筐体７内部の磁界分布を示す。この磁界分布は図３の（ｃ）の磁界分布に対応している。一方、ケース１では周波数1015ＭＨｚにおける磁界分布は乱れて周回パターンを確認することはできなかった。これは図３の（ｃ）は筐体７の底面の中心を磁力線が取り巻くモードであり、回路基板１５を同位置においたとき励振条件を満足できないからである。
【００１９】
このように電子機器２６が設けられる筐体７の寸法で決まる共振周波数ｆの電磁界分布と、筐体７を振動させる電子機器２６の位置関係に着目して、図３の（ｃ）に示すように、筐体７の共振周波数ｆにおいて周回する磁界分布の中心部分に電子機器２６を有する回路基板１５を設置することにより、電磁波ノイズを低減することができる。
【００２０】
この電子機器２６からの電磁波ノイズを低減することができる筐体７内の位置に、電子機器２６を自動的かつ効率的に取り付ける電子機器取付装置に付いて説明する。電子機器取付装置４０は、図９のブロック図に示すように、電子機器２６を保持して筐体７の所定の位置に移動させて位置決めするチャッキング手段４１と、チャッキング手段４１を移動させるモータや駆動力伝達機構などを有する駆動手段４２と、入力手段４３と演算手段４４と計測手段４５及び制御手段４６を有する。入力手段４３は電子機器２６が取り付られる筐体７の寸法情報を入力する。演算手段４４は入力手段４３で入力した筐体７の寸法データにより筐体７における複数の共振周波数ｆで周回する磁界分布のベクトルを演算する。計測手段４５は、例えば図４に示すループアンテナ３０とスペクトラムアナライザ３１などを有し、取付対象である電子機器２６から放射される周波数毎に主要な磁界放射の磁界強度を計測する。制御手段４６は演算手段４４の演算結果と計測手段４５の計測結果から電磁波ノイズを低減する電子機器２６の取付位置を設定して、駆動手段４６を作動させて電子機器２６を位置決めさせる。
【００２１】
この電子機器取付装置４０により電子機器２６を筐体７に取付けるときは、図１０のフローチャートに示すように、チャッキング手段４１で保持した電子機器２６を取り付る筐体７の寸法情報を入力手段４３で入力して演算手段４４に送る（ステップＳ１）。演算手段４４は送られた筐体７の寸法データに基づき筐体７における複数の共振周波数ｆで周回する磁界分布のベクトルを演算する（ステップＳ２）。この状態で制御手段４６で駆動手段４２を駆動させてチャッキング手段４１で保持した電子機器２６を移動しながら計測手段４５で電子機器２６から放射される周波数毎に主要な磁界放射の磁界強度を計測する（ステップＳ３）。制御手段４６は演算手段４４の演算結果と計測手段４５の計測結果を入力し、電磁波ノイズの低減する電子機器２６の取付位置を設定し、駆動手段４６の駆動を制御して、設定された取付位置に電子機器２６を位置決めして配置する（ステップＳ４）。このようにして筐体７の電磁波ノイズが最も少ない位置に電子機器２６を自動的に配置して取付けることができる。
【００２２】
前記説明では複写機１の原稿読取部２を設けた筐体７と信号処理部１４を例にして電磁波ノイズの低減について説明したが、一部に外部に通じる開口や隙間などが存在する筐体７内に電子機器類が設置される各種の電子応用装置においても同様に適用することができる。
【００２３】
【発明の効果】
この発明は以上説明したように、電子機器が取り付られる筐体の寸法情報により筐体における複数の共振周波数で周回する磁界分布のベクトルを演算し、電子機器から放射される周波数毎に主要な磁界放射の磁界強度を計測し、この演算結果と計測結果から計測された電子機器から放射される磁界放射の磁界強度が最も高い周波数で周回する磁界分布の中心部分を電子機器の取付位置に設定することにより、電子機器から放射される電磁波ノイズを低減することができる。
【００２５】
また、画像読取装置の光学系で読み取った光学情報を電気的情報に変換する信号処理手段を、画像読取装置の筐体の寸法情報により筐体における複数の共振周波数で周回する磁界分布のベクトルを演算し、信号処理手段から放射される周波数毎に主要な磁界放射の磁界強度を計測し、この演算結果と計測結果から計測された信号処理手段から放射される磁界放射の磁界強度が最も高い周波数で周回する磁界分布の中心部分を信号処置手段の取付位置に設定することにより、画像読取装置の外部へ漏洩する電磁波ノイズを減少することができ、電磁波による影響を低減することができる。
【図面の簡単な説明】
【図１】複写機の概要を示す構成図である。
【図２】電子機器と開口部を有する筐体の位置関係を示す模式図である。
【図３】共振周波数に対応する磁界パターンを示す模式図である。
【図４】電子機器の磁界強度の計測手段の構成図である。
【図５】各周波数に対する磁界強度の変化特性図である。
【図６】開口部を有する筐体に内蔵された電子機器の配置を示す平面図である。
【図７】周波数に対する電界強度変化特性図である。
【図８】周波数1015ＭＨｚにおける磁界強度分布図である。
【図９】電子機器取付装置の構成を示すブロック図である。
【図１０】電子機器取付装置の動作を示すフローチャートである。
【符号の説明】
１；複写機、２；原稿読取部、３；画像形成部、４；給紙装置、
５；開口部、６；コンタクトガラス、７；筐体、８；光学系、
９；信号処理系、１４；信号処理部、１５；回路基板、２６；電子機器、
４０；電子機器取付装置、４１；チャッキング手段、４２；駆動手段、
４３；入力手段、４４；演算手段、４５；計測手段、４６；制御手段。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic device mounting method for mounting various electronic devices and the like on a casing, an electronic device mounting device and an image reading device , and more particularly to reduction of electromagnetic noise leaking to the outside.
[0002]
[Prior art]
In recent years, with the increase in functions and clocks of electronic devices, obstacles due to electromagnetic waves generated from the electronic devices have become a problem. In particular, in an image reading unit such as a copying machine, the number of clocks is increased to improve the image quality, and the influence of leaked electromagnetic noise on each unit has become a further problem. In order to cope with this problem, as shown in, for example, Japanese Patent Laid-Open No. 5-199340, an electronic device portion including electronic components such as an image reading unit, an image writing unit, and a primary signal processing unit for correcting an image signal is provided. It is housed in a grounded conductive casing to provide an electromagnetic shield to reduce electromagnetic noise leaking outside the casing.
[0003]
[Problems to be solved by the invention]
However, if the frequency of the operation clock in each part of a copier, etc., increases, the problem that the chassis to which the electronic device is attached oscillates, and even if the chassis is grounded and the electromagnetic shield is used, the electromagnetic interference is dealt with. There is a disadvantage that it is not a fundamental solution.
[0004]
In particular, in an image forming apparatus such as a copying machine, a reading device having a high-frequency operation clock and a signal processing unit are installed in a housing of an image reading unit, and a document to be read is structurally arranged on the upper surface of the image reading unit. Therefore, it is difficult to completely shield the entire casing due to the presence of the opening, and leakage of electromagnetic noise is likely to occur.
[0005]
The present invention improves such disadvantages, and pays attention to the electromagnetic field distribution of the resonance frequency determined by the dimensions of the housing in which the electronic device is mounted and the positional relationship of the electronic device that vibrates the housing, and reduces electromagnetic noise with a simple configuration. It is an object of the present invention to provide an electronic device mounting method, an electronic device mounting device, and an image reading device capable of achieving the above.
[0006]
[Means for Solving the Problems]
An electronic device mounting method according to the present invention is an electronic device mounting method for reducing electromagnetic interference generated in an electronic device installed inside a casing having a gap or opening leading to the outside, and the electronic device is attached to the electronic device mounting method. A step of inputting dimensional information of the case, a step of calculating a magnetic field distribution vector that circulates at a plurality of resonance frequencies in the case based on the input size data of the case, and a key for each frequency emitted from the electronic device. Based on the step of measuring the magnetic field intensity of the magnetic field radiation, the vector of the magnetic field distribution that circulates at a plurality of resonance frequencies in the calculated housing and the magnetic field intensity of the main magnetic field radiation for each frequency radiated from the measured electronic device, Steps for setting the central part of the magnetic field distribution that circulates at the frequency at which the magnetic field intensity of the magnetic field radiation radiated from the electronic device is the highest, and the set mounting position Characterized by a step of placing the electronic device.
[0007]
An electronic device mounting apparatus according to the present invention is an electronic device mounting device that reduces electromagnetic interference generated in an electronic device installed inside a casing having a gap or opening that communicates with the outside, and includes chucking means and driving means. And an input means, a calculation means, a measurement means, and a control means, the chucking means holds the electronic device, the driving means moves and positions the chucking means, and the input means is a casing to which the electronic device is attached. The calculation means calculates a magnetic field distribution vector that circulates at a plurality of resonance frequencies in the casing from the casing dimension data input by the input means, and the measuring means calculates each frequency radiated from the electronic device. the magnetic field strength of the primary magnetic field radiation is measured, the control means based on the measurement result of the operation result and the measurement unit of the arithmetic means, radiated from electronic equipment measured by the measuring means The central part of the magnetic field distribution that circulates at the frequency at which the field intensity of the field radiation is the highest is set as the mounting position of the electronic device, and the driving device is driven to place the electronic device held by the chucking device at the set mounting position. It is characterized by.
[0009]
An image reading apparatus according to the present invention includes a housing having an opening on a side of a contact glass on which a document is placed, and an optical system that is provided inside the housing and reads information on the document placed on the contact glass. And a signal processing means for converting optical information read by the optical system into electrical information, and calculating a magnetic field distribution vector that circulates at a plurality of resonance frequencies in the housing based on the housing dimension data The magnetic field intensity of the main magnetic field radiation is measured for each frequency radiated from the signal processing means, and the calculated magnetic field distribution vector that circulates at a plurality of resonance frequencies in the housing and the frequency radiated from the measured signal processing means. Based on the magnetic field strength of each main magnetic field radiation, the signal processing is performed on the central part of the magnetic field distribution that circulates at the highest frequency of the magnetic field radiation emitted from the signal processing means. Set the mounting position of the stage, characterized in that a signal processing unit to a mounting position set.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing an outline of a copying machine. As shown in the figure, the copying machine 1 includes a document reading unit 2, an image forming unit 3, and a paper feeding device 4. The document reading unit 2 is provided in an opening 5 formed in the upper part of the apparatus main body, and includes a contact glass 6 on which a document is placed, and an interior of a housing 7 in which the opening 5 is formed on the installation side of the contact glass 6. The optical system 8 and the signal processing system 9 are provided. The optical system 8 includes a light source 10 that illuminates a document placed on the contact glass 6, a plurality of reflecting mirror groups 11 that deflect reflected light from the document, an imaging lens 12, and the like. Signal processing including a photoelectric conversion element 13 that receives and photoelectrically converts a document image formed by the image lens 12 and receives various pieces of signal processing from the photoelectric conversion element 13 and performs various signal processing. And a circuit board 15 on which the signal processing unit 14 is mounted.
[0011]
The image forming section 3 receives a control signal from the signal processing section 14, scans / exposures with a polygon mirror 16 that deflects a laser beam emitted from a laser light source that is controlled to emit light, and a laser beam deflected by the polygon mirror 16. The photosensitive member 17 is composed of an electrophotographic process unit 21 and a fixing unit 22 including a charging charger 18, a developing unit 19, a transfer charger 20, and the like disposed around the photosensitive member 17. A sheet feeding device 4 is disposed below the image forming unit 3. The paper feeding device 3 includes a paper feeding cassette 23 for storing recording paper, a transport roller 24, a paper discharge roller 25, and the like. The recording paper fed from the paper feeding cassette 23 is formed on the photoconductor 17 of the image forming unit 3. The transferred toner image is transferred by the transfer charger 20, and the recording paper on which the toner image has been transferred is heated and pressed by the fixing unit 22 to be fixed, and is discharged to the outside by the paper discharge roller 25.
[0012]
In this copying machine 1, the document reading unit 3 is provided with a signal processing system 9 having a photoelectric conversion element 13, a signal processing unit 14, and a circuit board 15 inside a housing 7 in which an opening 5 is partially formed. In particular, since the signal processing unit 14 is composed of various electronic components and electronic devices such as units, magnetic field noise that is electromagnetic wave noise is generated during operation. The positional relationship between the electronic device 26 constituting the signal processing unit 14 and the housing 7 having the opening 5 is shown in the schematic diagram of FIG. When the lengths of the housing 7 in the X, Y, and Z directions are a, b, and c, respectively, and the speed of electromagnetic waves is v, the resonance frequency f of the housing 7 can be expressed by the following equation (1).
[0013]
[Expression 1]

[0014]
In the above equation, m, n, and q indicate the number of magnetic field patterns in the X, Y, and Z directions, respectively. Here, for example, if the outer dimensions of the housing 7 are a = 0.5 m, b = 0.4 m, and c = 0.05 m, the resonance frequency f is as shown in the following table.
[0015]
[Table 1]

[0016]
Magnetic field patterns corresponding to the resonance frequencies 480 MHz to 1644 MHz of (a) to (f) are as shown in (a) to (f) of FIG. FIG. 3 shows a magnetic field distribution 27 that goes around the housing 7 as viewed from above the Z axis.
[0017]
On the other hand, the intensity of each frequency component of the magnetic field radiated from the electronic device 26 constituting the signal processing unit 14 is measured using a loop antenna 30 and a spectrum analyzer 31 as shown in FIG. Show. As shown in FIG. 5, it can be seen that the magnetic field noise is highest at a frequency of 970 MHz. The magnetic field distribution of the housing 7 at this frequency of 970 MHz is shown in FIG. From these facts, in order to reduce magnetic field noise at a frequency of 970 MHz, magnetic field noise radiated from the electronic device 26 is reduced by disposing the electronic device 26 in the central portion of the circulating magnetic field distribution 27 shown in FIG. Can be reduced.
[0018]
The result of having verified this by numerical simulation is shown. This verification is based on the electromagnetic field propagation behavior when the position of the circuit board 15 of the signal processing unit 14 having the electronic device 26 that is a noise source built in the housing 7 having the opening 5 is changed as shown in FIG. The simulation was performed by the finite difference time domain method. In this analysis, the analysis space is divided into a grid and the Maxwell equations are subtracted and solved in the time domain. Specifically, information in the frequency domain can be obtained by inputting a pulse to the input end of the circuit board 15 which is an input point and Fourier-transforming the waveform with respect to the output. The circuit board 15 has a line 15a. Here, when the dimensions of the casing 7 are a = 0.5 m, b = 0.4 m, and c = 0.05 m, the resonance frequency f at m = 3, n = 1, and q = 0 is 974 MHz from the above equation (1). It is. Here, in FIG. 6, the distance between the end of the circuit board 15 and the housing 7 in the X direction is e, and the case 1 in which the circuit board 15 is arranged at the center of the housing 7 at e = 0.23 m and the comparative example. FIG. 7 shows the propagation characteristics of the electric field strength at each frequency by calculating the electromagnetic field propagation behavior in the case 2 in which the circuit board 15 is arranged at the position of e = 0.01 m. As shown in FIG. 7, since the opening 5 is open, the resonance frequency f is shifted from 974 MHz to 1015 MHz. In the case 1, the magnetic field strength is ½ or less compared to the case 2. You can see that The magnetic field strength distribution at a frequency of 1015 MHz in case 2 is shown in FIG. FIG. 8 shows the magnetic field distribution inside the housing 7 when 1.0E-01 A / m in the magnetic field strength is 0 dB. This magnetic field distribution corresponds to the magnetic field distribution shown in FIG. On the other hand, in Case 1, the magnetic field distribution at a frequency of 1015 MHz was disturbed, and the circulation pattern could not be confirmed. This is because (c) in FIG. 3 is a mode in which the magnetic field lines surround the center of the bottom surface of the housing 7, and the excitation condition cannot be satisfied when the circuit board 15 is placed at the same position.
[0019]
Focusing on the electromagnetic field distribution of the resonance frequency f determined by the dimensions of the housing 7 in which the electronic device 26 is provided and the positional relationship of the electronic device 26 that vibrates the housing 7, as shown in FIG. Thus, electromagnetic wave noise can be reduced by installing the circuit board 15 having the electronic device 26 in the central portion of the magnetic field distribution that circulates at the resonance frequency f of the housing 7.
[0020]
An electronic device mounting apparatus that automatically and efficiently mounts the electronic device 26 at a position in the housing 7 where electromagnetic wave noise from the electronic device 26 can be reduced will be described. As shown in the block diagram of FIG. 9, the electronic device mounting apparatus 40 holds the electronic device 26 and moves it to a predetermined position of the housing 7, and moves the chucking unit 41. It has a drive means 42 having a motor, a driving force transmission mechanism, etc., an input means 43, a calculation means 44, a measurement means 45, and a control means 46. The input means 43 inputs dimension information of the housing 7 to which the electronic device 26 is attached. The computing means 44 computes a magnetic field distribution vector that circulates at a plurality of resonance frequencies f in the housing 7 based on the dimension data of the housing 7 input by the input means 43. The measuring unit 45 includes, for example, the loop antenna 30 and the spectrum analyzer 31 shown in FIG. 4 and measures the magnetic field intensity of main magnetic field radiation for each frequency radiated from the electronic device 26 to be attached. The control unit 46 sets the mounting position of the electronic device 26 that reduces electromagnetic noise from the calculation result of the calculation unit 44 and the measurement result of the measurement unit 45, and operates the driving unit 46 to position the electronic device 26.
[0021]
When the electronic device 26 is attached to the housing 7 by the electronic device attaching device 40, as shown in the flowchart of FIG. 10, the dimension information of the housing 7 to which the electronic device 26 held by the chucking means 41 is attached is input. Input by means 43 and send to calculation means 44 (step S1). The computing means 44 computes a magnetic field distribution vector that circulates at a plurality of resonance frequencies f in the housing 7 based on the dimension data of the housing 7 sent (step S2). In this state, the driving means 42 is driven by the control means 46 and the electronic device 26 held by the chucking means 41 is moved, and the magnetic field intensity of the main magnetic field radiation is obtained for each frequency emitted from the electronic device 26 by the measuring means 45. Measurement is performed (step S3). The control means 46 inputs the calculation result of the calculation means 44 and the measurement result of the measurement means 45, sets the mounting position of the electronic device 26 that reduces electromagnetic noise, controls the driving of the driving means 46, and sets the set attachment The electronic device 26 is positioned and arranged at the position (step S4). In this way, the electronic device 26 can be automatically arranged and attached at a position where the electromagnetic wave noise of the housing 7 is the least.
[0022]
In the above description, the electromagnetic noise reduction has been described by taking the case 7 and the signal processing unit 14 provided with the document reading unit 2 of the copying machine 1 as an example. However, the case in which some openings or gaps exist to the outside. The present invention can be similarly applied to various electronic application devices in which electronic devices are installed in the apparatus 7.
[0023]
【The invention's effect】
As described above, the present invention calculates a magnetic field distribution vector that circulates at a plurality of resonance frequencies in the housing based on the dimensional information of the housing to which the electronic device is mounted, and is used for each frequency emitted from the electronic device. Measure the magnetic field intensity of the magnetic field radiation, and set the center part of the magnetic field distribution that circulates at the highest frequency of the magnetic field intensity of the magnetic field radiation radiated from the electronic device measured from this calculation result and measurement result as the mounting position of the electronic device By doing so, the electromagnetic wave noise radiated | emitted from an electronic device can be reduced.
[0025]
Further, the signal processing means for converting the optical information read by the optical system of the image reading device into electrical information is converted into a magnetic field distribution vector that circulates at a plurality of resonance frequencies in the case according to the size information of the case of the image reading device. Calculate and measure the magnetic field intensity of the main magnetic field radiation for each frequency radiated from the signal processing means, and the frequency with the highest magnetic field intensity of the magnetic field radiation radiated from the signal processing means measured from this calculation result and measurement result By setting the central portion of the magnetic field distribution that circulates at the mounting position of the signal processing means, electromagnetic noise that leaks to the outside of the image reading apparatus can be reduced, and the influence of electromagnetic waves can be reduced.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an outline of a copying machine.
FIG. 2 is a schematic diagram illustrating a positional relationship between an electronic device and a housing having an opening.
FIG. 3 is a schematic diagram showing a magnetic field pattern corresponding to a resonance frequency.
FIG. 4 is a configuration diagram of a magnetic field strength measuring unit of an electronic device.
FIG. 5 is a change characteristic diagram of magnetic field strength with respect to each frequency.
FIG. 6 is a plan view showing an arrangement of electronic devices built in a housing having an opening.
FIG. 7 is a characteristic diagram of electric field strength change with respect to frequency.
FIG. 8 is a magnetic field intensity distribution diagram at a frequency of 1015 MHz.
FIG. 9 is a block diagram illustrating a configuration of an electronic device mounting apparatus.
FIG. 10 is a flowchart showing the operation of the electronic device mounting apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1; Copy machine, 2; Document reading part, 3; Image formation part, 4: Paper feeder,
5; opening, 6; contact glass, 7; housing, 8; optical system,
9; signal processing system, 14; signal processing unit, 15; circuit board, 26; electronic equipment,
40; Electronic device mounting device; 41; Chucking means; 42; Driving means;
43; input means, 44; calculation means, 45; measurement means, 46; control means.

Claims

An electronic device mounting method for reducing electromagnetic interference generated in an electronic device installed inside a housing having a gap or opening leading to the outside,
Inputting dimension information of a housing to which the electronic device is attached;
A step of calculating a magnetic field distribution vector that circulates at a plurality of resonance frequencies in the housing from the input housing dimension data;
Measuring the magnetic field strength of the main magnetic field radiation for each frequency radiated from the electronic device;
The magnetic field radiation field radiated from the electronic device based on the calculated magnetic field distribution vector that circulates at a plurality of resonance frequencies and the measured magnetic field intensity of the main magnetic field radiation for each frequency radiated from the electronic device. A step of setting a central portion of a magnetic field distribution that circulates at a frequency having the highest intensity as a mounting position of the electronic device;
Placing the electronic device at a set mounting position;
An electronic device mounting method comprising:

An electronic device mounting apparatus that reduces electromagnetic interference generated in an electronic device installed inside a housing having a gap or opening leading to the outside,
Having chucking means, drive means, input means, calculation means, measurement means and control means,
The chucking means holds the electronic device,
The drive means moves and positions the chucking means;
The input means inputs dimension information of a housing to which the electronic device is attached,
The computing means computes a magnetic field distribution vector that circulates at a plurality of resonance frequencies in the housing from the housing dimension data input by the input means,
The measuring means measures the magnetic field intensity of main magnetic field radiation for each frequency radiated from the electronic device,
The control means is based on the calculation result of the calculation means and the measurement result of the measurement means, and the magnetic field distribution of the magnetic field circulated at the highest frequency of the magnetic field intensity of the magnetic field radiation radiated from the electronic device measured by the measurement means. Set the central part to the mounting position of the electronic device,
Arranging the electronic device held by the chucking means at the attachment position by driving the driving means;
An electronic device mounting apparatus characterized by the above.

A housing having an opening on the side of the contact glass on which the document is placed, an optical system provided inside the housing for reading information on the document placed on the contact glass, and read by the optical system In an image reading apparatus having signal processing means for converting optical information into electrical information,
A magnetic field distribution vector that circulates at a plurality of resonance frequencies in the casing is calculated from the dimension data of the casing, and the magnetic field intensity of main magnetic field radiation is measured for each frequency radiated from the signal processing means. The magnetic field radiation field radiated from the signal processing means based on the magnetic field distribution vector that circulates at a plurality of resonance frequencies in the body and the measured magnetic field intensity of the main magnetic field radiation for each frequency radiated from the signal processing means. An image reading apparatus, wherein a central portion of a magnetic field distribution that circulates at a frequency having the highest intensity is set as an attachment position of the signal processing means, and the signal processing means is arranged at the set attachment position.