JP2003332787A - Method and device for fixing electronic apparatus, electronic application apparatus and image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce electromagnetic noise of a housing for mounting an electronic apparatus through a simple arrangement. <P>SOLUTION: In the method for fixing an electronic apparatus, information of the field strength of a main field being radiated from the electronic apparatus 26 disposed in the housing 7 having an opening communicating with the outside is measured for each frequency. The vector of field distribution circulating at a plurality of frequencies is operated from the dimensions of the housing 7 and the electronic apparatus 26 is disposed in the center of the circulating vector of field distribution thus reducing electromagnetic noise leaking from the electronic apparatus 26 to the outside. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device mounting method for mounting various electronic devices and the like in a housing, an electronic device mounting device, an electronic application device, and an image reading device, and more particularly to reduction of electromagnetic noise leaking to the outside. is there.

[0002]

2. Description of the Related Art In recent years, problems with electromagnetic waves generated from electronic devices have become a problem as electronic devices have advanced functions and clocks. In particular, in the image reading section of a copying machine or the like, the number of clocks is increasing for higher image quality, and the influence of leaked electromagnetic noise on each section is becoming a further problem. To address this problem, for example, Japanese Patent Laid-Open No. Hei 5
As disclosed in Japanese Patent Laid-Open No. 199340, an electronic device portion including electronic components such as an image reading unit, an image writing unit, and a primary signal processing unit that corrects an image signal is provided inside a grounded conductive casing. It is housed in an electromagnetic shield to reduce electromagnetic noise leaking to the outside of the housing.

[0003]

However, when the frequency of the operating clock in each part of the copying machine or the like becomes high, there arises a problem that the housing itself to which the electronic equipment is attached oscillates, and the housing is grounded to cause electromagnetic interference. The disadvantage is that even if shielded, it is not a fundamental solution to dealing with electromagnetic interference.

Particularly in an image forming apparatus such as a copying machine,
A reading device for a high-frequency operation clock and a signal processing unit are installed in the housing of the image reading unit, and an opening into which a contact glass on which a document to be read is set is structurally set on the upper surface of the image reading unit. Since it is formed, it is difficult to completely electromagnetically shield the entire housing due to the presence of the opening, and electromagnetic noise is likely to leak.

The present invention solves the above drawbacks, pays attention to the electromagnetic field distribution of the resonance frequency determined by the size of the housing in which the electronic device is mounted and the positional relationship of the electronic device that vibrates the housing, and has a simple structure to reduce electromagnetic noise. It is an object of the present invention to provide an electronic device mounting method, an electronic device mounting device, an electronic application device, and an image reading device that can reduce the number of electronic devices.

[0006]

An electronic device mounting method according to the present invention is an electronic device mounting method for reducing an electromagnetic interference wave generated in an electronic device installed inside a housing having a gap or an opening communicating with the outside. The magnetic field strength information of the main magnetic field radiation is measured for each frequency radiated from the electronic device, and the vector of the magnetic field distribution that orbits at a plurality of resonance frequencies is calculated according to the dimensions of the housing to calculate the magnetic field distribution. The electronic device is installed in the central portion of the vector which circulates to reduce electromagnetic wave noise leaking to the outside.

The electronic device mounting device of the present invention is an electronic device mounting device for reducing electromagnetic interference waves generated in an electronic device installed inside a housing having a gap or an opening communicating with the outside, which is a chucking means. And a driving means, an inputting means, a computing means, a measuring means, and a controlling means, the chucking means holds the electronic device, the driving means moves and positions the chucking means, and the input means is taken by the electronic device. The dimensional information of the attached housing is input, and the calculating means calculates the vector of the magnetic field distribution that circulates at a plurality of resonance frequencies in the housing based on the dimensional data of the housing input by the input means, and the measuring means radiates from the electronic device. The magnetic field intensity of the main magnetic field radiation is measured for each frequency to be controlled, and the control means controls the mounting position of the electronic device to reduce electromagnetic noise from the calculation result of the calculation means and the measurement result of the measurement means. Set by operating the drive means, characterized in that for positioning the electronic device.

The electronic application apparatus of the present invention is characterized in that the electronic device is attached to the housing by the electronic device attaching method.

According to the image reading apparatus of the present invention, the optical information of the original read by the optical system is converted into electrical information in the housing having the opening for installing the contact glass on which the original is placed, by the electronic device mounting method. An electronic device of signal processing means for processing is attached.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing the outline of a copying machine. As shown in the figure, the copying machine 1 has 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 inside a contact glass 6 on which a document is placed, and 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 in the. The optical system 8 is a light source 10 for illuminating a document placed on the contact glass 6.
And a plurality of reflecting mirror groups 11 for deflecting the reflected light from the document, an imaging lens 12, and the like.
Is composed of a photoelectric conversion element 13 which receives an original image formed by the image forming lens 12 and photoelectrically converts it, and an electronic device such as an electronic component or unit which receives image information from the photoelectric conversion element 13 and performs various signal processing. The signal processing unit 14 includes a signal processing unit 14 and a circuit board 15 on which the signal processing unit 14 is mounted.

The image forming section 3 receives a control signal from the signal processing section 14 and deflects a laser beam emitted from a laser light source whose emission is controlled, and a polygon mirror 16 for deflecting the laser beam. The photosensitive member 17 to be scanned / exposed, an electrophotographic process unit 21 including a charging charger 18, a developing unit 19, and a transfer charger 20 arranged around the photosensitive member 17, a fixing unit 22, and the like. A paper feeding device 4 is provided below the image forming unit 3.
Are arranged. The paper feeding device 3 includes a paper feeding cassette 23 for accommodating recording paper, a conveying roller 24, a paper ejection 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 toner image thus transferred 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 the discharge roller 2
5 is discharged to the outside.

In the copying machine 1, the document reading section 3 is
A signal processing system 9 including a photoelectric conversion element 13, a signal processing unit 14, and a circuit board 15 is provided inside a housing 7 in which a part of the opening 5 is formed. Since it is composed of electronic devices such as electronic parts and units, magnetic field noise, which is electromagnetic wave noise, is generated during operation. The positional relationship between the electronic device 26 forming the signal processing unit 14 and the housing 7 having the opening 5 is shown in the schematic diagram of FIG. The lengths of the housing 7 in the X, Y, and Z directions are a,
Assuming that the speed of the electromagnetic wave is v for b and c, the resonance frequency f of the housing 7 can be expressed by the following equation (1).

[0013]

[Equation 1]

In the above equation, m, n and q represent the numbers of magnetic field patterns in the X, Y and Z directions, respectively. Here, for example, the outer dimensions of the housing 7 are a = 0.5 m, b = 0.4 m, and c = 0.
When the distance is 05m, the resonance frequency f is as shown in the table below.

[0015]

[Table 1]

Resonance frequency of each of (a) to (f) 480M
Magnetic field patterns corresponding to Hz to 1644 MHz are as shown in (a) to (f) of FIG. FIG. 3 shows a magnetic field distribution 27 that orbits the housing 7 when viewed from above the Z axis.

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 by using the loop antenna 30 and the spectrum analyzer 31, as shown in FIG. As shown in FIG. As shown in FIG. 5, 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 the magnetic field noise at the frequency of 970 MHz, by disposing the electronic device 26 in the central portion of the circulating magnetic field distribution 27 shown in FIG.
The magnetic field noise radiated from the can be reduced.

The results of verifying this by numerical simulation will be shown. This verification is performed by using the opening 5 as shown in FIG.
2 which is a noise source built in a housing 7 having
The electromagnetic field propagation behavior when the position of the circuit board 15 of the signal processing unit 14 having 6 was changed was evaluated by performing simulation by the finite difference time domain method. In this analysis, the analysis space is divided into grids and Maxwell's equations are differentiated 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 performing Fourier transform on the waveform of the output. In addition, the circuit board 15 has a line 15a.
There is. Here, the dimensions of the housing 7 are a = 0.5 m and b = 0.4.
If m and c = 0.05 m, then m = 3 and n from the equation (1).
The resonance frequency f at = 1 and q = 0 is 974 MHz. Here, in FIG. 6, the end portion of the circuit board 15 and the housing 7
Where e is the distance in the X direction and the circuit board 15 is arranged at the center of the housing 7 at e = 0.23 m, and the case 2 in which the circuit board 15 is arranged at the position e = 0.01 m as a comparative example.
The electromagnetic field propagation behavior in the case of is calculated from the electric field directly above the opening 5, and the propagation characteristics of the electric field strength at each frequency are shown in FIG. As shown in FIG. 7, since the opening 5 is opened, the resonance frequency f is shifted from 974 MHz to 1015 MHz, but in the case 1 the magnetic field strength is 1/2 or less compared to the case 2. You can see that The magnetic field strength distribution at the frequency of 1015 MHz in this case 2 is shown in FIG. Fig. 8 shows that 1.0E-01A / m at magnetic field strength is 0d.
The magnetic field distribution inside the housing 7 when B is shown. 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) of 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 in the same position.

As described above, 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 housing 7
Paying attention to the positional relationship of the electronic device 26 that causes the vibration of FIG.
As shown in (c), the 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 circulating at the resonance frequency f of the housing 7.

An electronic equipment mounting device for automatically and efficiently mounting the electronic equipment 26 at a position in the housing 7 where electromagnetic wave noise from the electronic equipment 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 the chucking means 41 to a predetermined position of the housing 7 to position the chucking means 41.
A driving means 42 having a motor for moving the chucking means 41 and a driving force transmission mechanism, an input means 43, a computing means 44, a measuring means 45 and a control means 46. The input means 43 is a housing 7 to which the electronic device 26 is attached.
Enter the dimension information of. The computing unit 44 computes a vector of the magnetic field distribution that orbits the housing 7 at a plurality of resonance frequencies f based on the dimension data of the housing 7 input by the input unit 43. The measuring means 45 has, for example, the loop antenna 30 and the spectrum analyzer 31 shown in FIG. 4, and measures the magnetic field intensity of the 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,
The drive means 46 is operated to position the electronic device 26.

When the electronic device 26 is attached to the housing 7 by the electronic device mounting device 40, the dimensions of the housing 7 to which the electronic device 26 held by the chucking means 41 is attached, as shown in the flowchart of FIG. Information is input by the input means 43 and sent to the arithmetic means 44 (step S1). The calculation means 44 calculates the vector of the magnetic field distribution that orbits the housing 7 at a plurality of resonance frequencies f based on the sent dimension data of the housing 7 (step S2). In this state, the control means 4
6, the driving means 42 is driven to move the electronic equipment 26 held by the chucking means 41, and the measuring means 45 measures the magnetic field strength of the main magnetic field emission for each frequency radiated from the electronic equipment 26 (step S3). ). The control unit 46 inputs the calculation result of the calculation unit 44 and the measurement result of the measurement unit 45, sets the mounting position of the electronic device 26 that reduces electromagnetic noise, controls the drive of the driving unit 46, and sets the set mounting position. 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 the position where the electromagnetic wave noise of the housing 7 is the smallest.

In the above description, the case 7 in which the document reading section 2 of the copying machine 1 is provided and the signal processing section 14 have been described as an example of the reduction of electromagnetic noise, but there are some openings and gaps communicating with the outside. The same can be applied to various electronic application devices in which electronic devices are installed in the housing 7.

[0023]

As described above, the present invention measures the information on the magnetic field strength of the main magnetic field emission for each frequency radiated from the electronic equipment installed inside the housing having the gap or opening communicating with the outside. Then, by calculating the vector of the magnetic field distribution circulating at a plurality of resonance frequencies according to the dimensions of the casing and installing the electronic device at the center of the circulating vector of the magnetic field distribution, electromagnetic waves leaking to the outside of the casing Noise can be reduced.

Further, the vector of the magnetic field distribution circulating at a plurality of resonance frequencies in the housing is calculated according to the size information of the housing to which the electronic equipment is attached, and the magnetic field of the main magnetic field radiation is emitted for each frequency emitted from the electronic equipment. By measuring the strength and setting the mounting position of the electronic device that reduces the electromagnetic noise from the calculation result and the measurement result, the installation position of the electronic device that reduces the electromagnetic noise leaking to the outside of the housing can be configured with a simple configuration. Can be set.

Further, by mounting the electronic device in the housing by this electronic device mounting method, it is possible to reduce electromagnetic wave noise leaking to the outside of the electronic application device or the image reading device, and to reduce the influence of the electromagnetic wave. it can.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an outline of a copying machine.

FIG. 2 is a schematic diagram showing 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 strength distribution diagram at a frequency of 1015 MHz.

FIG. 9 is a block diagram showing 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; Copier, 2; Original reading part, 3; Image forming part, 4; Paper feeding device, 5; Opening part, 6; Contact glass, 7; Housing, 8; Optical system, 9; Signal processing system, 14 ; Signal processing unit,
15: circuit board, 26; electronic device, 40; electronic device mounting device, 41; chucking means, 42; drive means, 4
3; input means, 44; calculation means, 45; measurement means, 4
6; control means.

Claims (4)

[Claims] 1. An electronic device mounting method for reducing an electromagnetic interference wave generated in an electronic device installed inside a housing having a gap or an opening communicating with the outside, the method being performed for each frequency radiated from the electronic device. The magnetic field intensity information of the main magnetic field radiation is measured, the vector of the magnetic field distribution that circulates at a plurality of resonance frequencies is calculated according to the dimensions of the housing, and the electronic device is installed in the central portion of the vector that circulates in the magnetic field distribution. An electronic device mounting method, which is characterized in that 2. An electronic equipment mounting device for reducing an electromagnetic interference wave generated in an electronic equipment installed inside a housing having a gap or an opening communicating with the outside, the chucking means, the driving means, and the input means. It has a computing means, a measuring means, and a control means, the chucking means holds the electronic equipment, the driving means moves and positions the chucking means, and the input means dimensional information of the housing to which the electronic equipment is attached. The calculation means calculates the vector of the magnetic field distribution that circulates at a plurality of resonance frequencies in the housing based on the dimensional data of the housing input by the input means, and the measurement means is a main unit for each frequency radiated from the electronic device. The magnetic field intensity of the magnetic field radiation is measured, and the control means operates the drive means by setting the mounting position of the electronic device that reduces electromagnetic noise from the calculation result of the calculation means and the measurement result of the measurement means. Electronic device mounting apparatus for causing positioning the electronic device. 3. An electronic application device, wherein the electronic device is attached to a housing by the electronic device attachment method according to claim 1. 4. The electronic device mounting method according to claim 1, wherein optical information of a document read by an optical system is converted into electrical information in a casing having an opening for installing a contact glass on which a document is placed. An image reading apparatus having an electronic device as signal processing means attached thereto.