JP2017117950A - Electronic apparatus and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively cool a substrate inside a housing, such as a shield case and an element on the substrate and reduce the size of the housing, while suppressing dust from entering the inside of the housing.SOLUTION: A control part 51 comprises: a main substrate 55; a shield case 53 that stores the main substrate 55; and a cooling fan 57 that is arranged separated from the main substrate 55. An inlet port 57a of the cooling fan 57 is directed to a middle wall plate 53b, and an exhaust direction M of the cooling fan 57 is inclined with respect to an upper wall plate 53c facing the main substrate 55; an air exhausted from the cooling fan 57 is obliquely blown to the upper wall plate 53c to be re-directed and flows to a surface of the main substrate 55 on which the element 58 is mounted; the upper wall plate 53c is formed of a member with a high thermal conductivity.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an electronic device and an image forming apparatus including the electronic device, and more particularly to a technique for cooling an element on a substrate in the electronic device.

  The image forming apparatus is provided with a plurality of types of substrates such as a power supply substrate and a control substrate, and these substrates are covered with a shielding member that blocks noise. In addition, when elements such as transistors and integrated circuits that generate large amounts of heat are provided on these substrates, these elements need to be cooled.

  For example, in Patent Document 1, an electrical board is accommodated in a shield case, an air duct is connected to the shield case, and outside air is allowed to flow from the fan through the air duct to the inside of the shield case, and this air is parallel to the electrical board. To cool the elements on the electrical board.

  In Patent Document 2, air is blown out from a cooling fan in a direction parallel to the substrate, and the air is passed through both surfaces of the substrate to cool elements mounted on both surfaces of the substrate.

  Further, in Patent Document 3, the first wiring board and the second wiring board are arranged to face each other in the shield case, and air is blown out from the cooling fan in a direction orthogonal to the first wiring board and the second wiring board. The elements on the second wiring board are cooled, and the air is guided to the first wiring board through the ventilation holes of the second wiring board to cool the elements on the first wiring board.

JP 2002-182545 A JP 2007-48930 A JP 2005-340598 A

  However, when the outside air is directly flowed into the inside of the shield case through the air duct as in Patent Document 1, dust and dust easily enter the inside of the shield case together with the outside air. Or dust may adhere to elements on the electric circuit board and cause problems. For this reason, it is conceivable to let outside air flow into the shield case through the filter. However, the cooling efficiency of the air by the cooling fan is reduced, and the filter needs to be replaced or cleaned.

  Further, when air is allowed to flow in parallel with the substrate as in Patent Documents 1 and 2, the air passes through almost without hitting the surface of the substrate, so there is almost no cooling effect on the substrate, and the cooling effect on the elements on the substrate is low. Become.

  Furthermore, when air is flowed in a direction orthogonal to the substrate as in Patent Document 3, the substrate and the elements on the substrate can be effectively cooled, but the cooling fan and the substrate must be disposed oppositely, The space in the facing direction increases, which causes an increase in the size of the shield case.

  The present invention has been made in view of the above circumstances, and by appropriately setting the arrangement position and the exhaust direction of the cooling fan, while preventing dust and dust from entering the casing such as a shield case, An object of the present invention is to provide an electronic device and an image forming apparatus capable of effectively cooling a substrate and elements on the substrate and reducing the size of the housing.

  An electronic device according to one aspect of the present invention has a distance in a direction along a mounting surface of an element of the substrate from the substrate, the substrate on which the element is mounted, a housing that houses the substrate, and the housing. A cooling fan disposed at a position separated from the housing, the air inlet of the cooling fan being directed to the first wall portion of the housing, and the exhaust direction of the cooling fan facing the substrate The cooling fan is inclined with respect to the second wall portion of the body so that the air exhausted from the cooling fan strikes the second wall portion obliquely and changes its direction to flow to the element mounting surface of the substrate. And the second wall portion is made of a member having a thermal conductivity higher than a predetermined thermal conductivity.

  An image forming apparatus according to an aspect of the present invention is an image forming apparatus including the electronic apparatus according to the present invention.

  According to the present invention, since the arrangement position and the exhaust direction of the cooling fan are set as appropriate, the substrate in the housing and the elements on the substrate are effective while suppressing dust and dust from entering the housing such as a shield case. The housing can be cooled and the housing can be downsized.

1 is a front sectional view showing the structure of an image forming apparatus according to an embodiment of the present invention. 2 is a plan view showing a structure of a control unit in the image forming apparatus. FIG. It is a perspective view which shows the structure of a control part. It is a perspective view which fractures | ruptures and shows a control part along AA of FIG. It is sectional drawing which shows the structure of a control part typically. It is a perspective view which shows a cooling fan.

  Hereinafter, an electronic apparatus and an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a front sectional view showing the structure of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus 1 according to the present embodiment includes an image reading unit (ISU) 5, an operation unit 47, an image forming unit 120, a fixing device 13, a paper feeding unit 14, a control unit 51, and an apparatus main body 2. A power supply unit 52 and the like are provided.

  The operation unit 47 is operated by a user and accepts execution instructions such as an image forming operation and an image reading operation.

  When performing an image reading operation, the image reading device 5 optically reads an image of a document and generates image data. Image data generated by the image reading device 5 is stored in a built-in HDD or a computer connected to a network.

  When performing an image forming operation, the image data generated by the image reading operation described above, image data received from a user terminal device such as a computer or smartphone connected to a network, or image data stored in a built-in HDD Based on this, the image forming unit 120 forms a toner image on the recording paper P as a recording medium supplied from the paper supply unit 14.

  The image forming unit 120 includes a magenta image forming unit 12M, a cyan image forming unit 12C, a yellow image forming unit 12Y, and a black image forming unit 12Bk. Each of the image forming units 12M, 12C, 12Y, and 12Bk exposes the surface of the photosensitive drum 122, the charging device that uniformly charges the surface of the photosensitive drum 122, and the surface of the photosensitive drum 122 to the surface. An exposure device (LSU) 123 that forms an electrostatic latent image, a developing device 124 that develops the electrostatic latent image on the surface of the photosensitive drum 122 into a toner image using toner, and a primary transfer roller 126 And each.

  When performing color printing, in each of the image forming units 12M, 12C, 12Y, and 12Bk, the surface of the photosensitive drum 122 is uniformly charged and then exposed, and the surface corresponds to an image of a color component of color. An electrostatic latent image is formed, the electrostatic latent image on the surface of the photosensitive drum 122 is developed, a toner image of the color component is formed on the photosensitive drum 122, and the toner image is driven by the primary transfer roller 126. Primary transfer is performed on the intermediate transfer belt 125 stretched between the roller 125A and the driven roller 125B.

  The intermediate transfer belt 125 has an image bearing surface on which the toner image is transferred on the outer circumferential surface thereof, and is driven by the driving roller 125 </ b> A while being in contact with the circumferential surface of the photosensitive drum 122. The intermediate transfer belt 125 runs endlessly between the driving roller 125A and the driven roller 125B while being synchronized with each photosensitive drum 122.

  The toner images of the respective color components transferred onto the intermediate transfer belt 125 are superimposed on the intermediate transfer belt 125 with the transfer timing adjusted to become a color toner image. The secondary transfer roller 210 transfers the color toner image formed on the surface of the intermediate transfer belt 125 from the paper supply unit 14 to the conveyance path 190 in the nip portion N between the secondary transfer roller 210 and the intermediate transfer belt 125. Secondary transfer is performed on the recording paper P that has been conveyed through.

  Thereafter, the recording paper P is heated and pressurized by the fixing device 13, the toner image on the recording paper P is fixed by thermocompression bonding, and the recording paper P is discharged to the discharge tray 151 through the discharge roller pair 159.

  The paper supply unit 14 accommodates a plurality of recording papers P, and rotates the pickup roller 145 to convey and supply the recording papers P to the conveyance path 190.

  The control unit 51 is connected to the image reading device 5, the fixing device 13, the image forming unit 120, the paper feeding unit 14, the operation unit 47, and the like, and controls the entire image forming apparatus 1. The power supply unit 52 is connected to a commercial power supply and supplies power to the entire image forming apparatus 1.

  By the way, in the control part 51 and the power supply part 52, a board | substrate etc. are accommodated in a shield case, and it is made not to receive the influence of an external noise or to prevent the leakage of an internal noise. In addition, since both the control unit 51 and the power supply unit 52 have a plurality of elements that generate a large amount of heat on the substrate, it is necessary to efficiently cool these elements using a cooling fan or the like. . However, it is not preferable that dust or dust easily enter the inside of the shield case through the cooling fan or that the shield case is enlarged due to the provision of the cooling fan.

  Therefore, in this embodiment, by appropriately setting the arrangement position and the exhaust direction of the cooling fan, the substrate and the elements on the substrate are effectively cooled while suppressing dust and dust from entering the shield case. Is miniaturized.

  Next, taking the control unit 51 as an example, the structure of such a shield case, substrate, and cooling fan will be described. FIG. 2 is a plan view showing the structure of the control unit 51. FIG. 3 is a perspective view showing the structure of the control unit 51. FIG. 4 is a perspective view showing the control unit 51 by cutting along the line AA in FIG. Further, FIG. 5 is a sectional view schematically showing the structure of the control unit 51.

  As shown in FIGS. 2 to 5, the control unit 51 includes a shield case 53, a frame 54, a main board 55, a sub board 56, a cooling fan 57, and the like. The shield case 53 is obtained by bending a plate material such as a metal having a shielding effect and thermal conductivity. The shield case 53 has a substantially rectangular parallelepiped shape, and includes a bottom wall plate 53a, a middle wall plate 53b, a top wall plate 53c, and side wall plates 53d to 53g located at a higher position than the bottom wall plate 53a. Yes. The shield case 53 is an example of a casing in the claims, the middle wall plate 53b is an example of a first wall portion in the claims, and the upper wall plate 53c is further claimed in the claims. It is an example of the 2nd wall part in a range.

  The frame 54 is provided at substantially the same height as the middle wall plate 53b, and a space Sp is formed between the frame 54 and the bottom wall plate 53a.

  The main board 55 and the sub board 56 are attached on the frame 54. The cooling fan 57 is attached on the middle wall plate 53 b of the shield case 53. Since the frame 54 and the middle wall plate 53b have substantially the same height, the main board 55, the sub board 56, and the cooling fan 57 are arranged at substantially the same height. Furthermore, other substrates, electronic components, etc. (not shown) are arranged in the space Sp between the frame 54 and the bottom wall plate 53a.

  A plurality of elements 58 are mounted on the mounting surface of the main substrate 55 and the mounting surface of the sub substrate 56. And about the two elements 58 on the mounting surface of the main board | substrate 55, since those calorific values are large, each heat sink 61 is attached. These heat sinks 61 are made of metal and have a plurality of heat radiating fins 61a that protrude vertically and are parallel to each other.

  The cooling fan 57 is disposed away from the main board 55 in the direction along the mounting surface of the main board 55. Further, the air inlet 57a of the cooling fan 57 is directed to the middle wall plate 53b. Further, the exhaust direction M of air from the exhaust port 57 d of the cooling fan 57 is set to be inclined with respect to the upper wall plate 53 c facing the mounting surface of the main board 55. Specifically, the exhaust direction M of the cooling fan 57 is inclined with respect to the direction orthogonal to the upper wall plate 53c, and is inclined toward the main board 55 and each heat sink 61 with respect to the orthogonal direction.

  Further, the exhaust direction M of the cooling fan 57 is slightly inclined with respect to the heat radiation fins 61a of the respective heat sinks 61 when the control unit 51 is viewed in plan as shown in FIG.

  In the shield case 53, the space Sp <b> 2 is provided at a position opposite to the position where the main board 55 is disposed and at a position on the intake port 57 a side of the cooling fan 57. .

  Further, in the shield case 53, it is preferable that the space Sp provided on the opposite side (back side) of the surface of the frame 54 on which the cooling fan 57 and the main board 55 are disposed is sealed.

  The radiating fins 61 a are parallel to the exhaust direction M of the cooling fan 57, that is, air that is exhausted from the cooling fan 57 and strikes the upper wall plate 53 c at an angle to the mounting surface of the main board 55. It may be a posture parallel to the flow of air and guide the air toward the exhaust hole 53h.

  In addition, a hole serving as an air inlet / outlet is not formed in the portion of the middle wall plate 53b facing the air inlet 57a of the cooling fan 57. Further, a plurality of exhaust holes 53 h are formed in the side wall plate 53 d located in the exhaust direction M of the cooling fan 57.

  FIG. 6 is a perspective view showing the cooling fan 57. As shown in FIG. 6, a pair of guide plates 57 c are provided substantially parallel to the exhaust direction M on both sides of the frame 57 b of the cooling fan 57.

  In such a configuration, when the cooling fan 57 is driven, air is sucked into the intake port 57a of the cooling fan 57 as shown by the white arrow in FIG. It is blown out. At this time, the air blown from the exhaust port 57d is guided in the exhaust direction M by the guide plates 57c of the cooling fan 57, and the air flow is concentrated on the main substrate 55 and the heat sinks 61 side. The exhaust direction M of the air from the exhaust port 57d of the cooling fan 57 is inclined with respect to the direction orthogonal to the upper wall plate 53c, and is inclined toward the main board 55 and each heat sink 61 with respect to the orthogonal direction. Therefore, the air exhausted from the exhaust port 57d of the cooling fan 57 strikes the upper wall plate 53c obliquely and diffuses while changing its direction, and flows to the mounting surface of the main board 55 and each heat sink 61. For this reason, air is blown onto the main board 55 itself and the other elements 58 on the mounting surface of the main board 55, and these are effectively cooled.

  Further, as shown in FIG. 2, since the exhaust direction M of the cooling fan 57 is not parallel to the heat radiation fins 61 a of the heat sinks 61 but slightly inclined, the air flowing into the heat sinks 61 flows through the heat sinks 61. It sprays so that it may hit the radiation fin 61a. For this reason, the radiation fin 61a of each heat sink 61 is effectively cooled by the air flow, and each element 58 to which each heat sink 61 is attached is also effectively cooled. Further, the air flow is guided by the heat radiating fins 61 a of the heat sinks 61, so that the elements 58 on the downstream side of the heat sinks 61 are effectively cooled.

  The air that has flowed and passed along the mounting surface of the main board 55 is discharged to the outside of the shield case 53 through the exhaust holes 53 h of the side wall plate 53 d located in the exhaust direction M of the cooling fan 57.

  On the other hand, since a hole serving as an inlet / outlet of air from the outside of the shield case 53 is not formed in the portion of the middle wall plate 53b facing the intake port 57a of the cooling fan 57, cooling is performed inside the shield case 53. An air flow that circulates to the intake port 57 a through the outer edge of the fan 57 is generated, and the air is sucked into the intake port 57 a of the cooling fan 57, and this air is exhausted from the exhaust port 57 d of the cooling fan 57. Then, while the air is recirculated inside the shield case 53 by the cooling fan 57, the air is discharged from the exhaust holes 53h, and the air is shielded through the gaps and small holes of the shield case 53 as the air recirculates and discharges. It flows into the inside of the case 53.

  Therefore, in the present embodiment, the air outside the shield case 53 is not directly taken into the intake port 57a of the cooling fan 57. For this reason, even if dust or dust is floating in the outside air, the dust or dust is not directly sucked into the intake port 57a of the cooling fan 57 together with the outside air, and is sucked and exhausted through the cooling fan 57. The amount of dust and dust can be suppressed, and the amount of dust and dust attached to the main board 55, each heat sink 61, and each element 58 can be reduced.

  Here, in the present embodiment, the air returning inside the shield case 53 is once applied to the upper wall plate 53c and the like, and then sprayed to the main board 55, each heat sink 61, and each element 58. The shield case 53 and the upper wall plate 53c have a material having a thermal conductivity higher than a predetermined thermal conductivity (for example, 80 W / m · K or more at a temperature of 0 °), for example, thermal conductivity. The upper wall plate 53 c is made of a plate material such as metal, and serves as an exterior wall of the shield case 53. For example, a metal material having high thermal conductivity such as aluminum or copper is preferably used for the shield case 53 and the upper wall plate 53c. For this reason, when the air recirculated inside the shield case 53 hits and contacts the upper wall plate 53c, the heat of the inner air is quickly conducted to the air outside the shield case 53 through the upper wall plate 53c. As a result, the temperature of the inner air is lowered. That is, even if the air recirculates inside the shield case 53, the temperature of the inner air decreases when it comes into contact with the upper wall plate 53c. Thereby, the heat sink 61 and the elements 58 can be cooled as necessary and sufficient.

  As described above, in this embodiment, the cooling fan 57 is disposed at a position away from the main board 55 in the direction along the mounting surface of the main board 55 (in the direction of arrow A in FIG. 5). Since the exhaust direction M of the air from the exhaust port 57d is inclined with respect to the upper wall plate 53c, the air exhausted from the exhaust port 57d of the cooling fan 57 strikes the upper wall plate 53c obliquely and diffuses while changing its direction. The temperature of the air is lowered by coming into contact with the upper wall plate 53c, and this air is blown onto the main board 55 itself, each heat sink 61 on the main board 55, and each element 58, and these are effective. To be cooled.

  Further, since the air inlet / outlet is not formed in the portion of the middle wall plate 53b facing the air inlet 57a of the cooling fan 57, the amount of dust and dust sucked and exhausted through the cooling fan 57 can be suppressed, and the main board can be suppressed. The amount of dust and dirt adhering to each heat sink 61 and each element 58 on 55 can be suppressed.

  Furthermore, since the cooling fan 57 is disposed at substantially the same height as the main board 55 and the sub board 56, the height of the shield case 53 can be suppressed and the shield case 53 can be reduced in size.

  In the above-described embodiment, the control unit 51 is described as an example. However, the present invention can be applied to the power supply unit 52 and the like, and further, a configuration in which a substrate is disposed inside the shield case. For example, the present invention can be applied to any kind of electronic equipment. Note that an electronic apparatus according to an embodiment of the present invention has an image forming mechanism (an image forming unit 120, a fixing unit 13, a paper feeding unit 14, a transport path 190 or a transport roller as a transport mechanism) necessary for image formation. Is an image forming apparatus 1 as an embodiment of the present invention.

  The configuration and processing described with reference to FIGS. 1 to 6 are only an embodiment of the present invention, and the present invention is not limited to the configuration and processing.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Apparatus main body 5 Image reading apparatus 13 Fixing apparatus 14 Paper feed part 47 Operation part 51 Control part 52 Power supply part 53 Shield case 54 Frame 55 Main board 56 Sub board 57 Cooling fan 58 Element 61 Heat sink 120 Image formation part

Claims (12)

A substrate on which the element is mounted;
A housing containing the substrate;
A cooling fan disposed at a position away from the substrate in a direction along the mounting surface of the element of the substrate within the housing,
The cooling fan has an air inlet directed toward the first wall portion of the housing, and an exhaust direction of the cooling fan is inclined with respect to the second wall portion of the housing facing the substrate, so that the cooling fan The cooling fan is disposed in such a posture that the air exhausted from the slant strikes the second wall portion and changes its direction to flow to the element mounting surface of the substrate,
The electronic apparatus which consists of a member in which the said 2nd wall part has heat conductivity higher than predetermined heat conductivity.   2. The electronic device according to claim 1, wherein a hole through which air from the outside of the housing passes is not provided in a portion of the first wall portion facing the air inlet of the cooling fan.   The electronic device according to claim 1, wherein the cooling fan includes a guide member that regulates air discharged from the cooling fan in a direction in which the air is obliquely applied to the second wall portion.   4. The electronic device according to claim 1, wherein the housing includes an exhaust hole that exhausts air that has flowed from the cooling fan to the mounting surface of the substrate.   The electronic device according to claim 1, wherein the second wall portion is an exterior wall of the housing.   The electronic device according to claim 1, wherein a heat sink is provided on an element on the substrate. The housing has an exhaust hole for exhausting air that has flowed from the cooling fan to the mounting surface of the substrate.
A heat sink is provided on the element on the substrate;
The heat sink has a plurality of radiating fins which are in a posture parallel to the air flow which is obliquely applied to the second wall portion and turned to the mounting surface of the substrate, and guides the air toward the exhaust hole. The electronic device according to claim 1, comprising:   7. The heat sink according to claim 6, wherein the heat sink has a plurality of radiating fins that are inclined rather than parallel to the air flow that is obliquely applied to the second wall portion and turned to the mounting surface of the substrate. Electronics.   The electronic device according to claim 8, wherein each of the heat dissipating fins guides air flowing on a mounting surface of the substrate.   The space inside the housing is provided at a position on the opposite side to the position where the board is disposed and on the inlet side of the cooling fan. The electronic device according to Crab.   11. The electronic device according to claim 1, wherein a sealed space is provided in the casing on a side opposite to a frame surface on which the cooling fan and the substrate are disposed. An image forming mechanism necessary for image formation on a recording medium;
An image forming apparatus comprising: the electronic device according to claim 1.