JP2013074083A - Shield box and image formation apparatus having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shield box capable of appropriately cooling, without increasing the apparatus size, electronic components including heat generating components arranged in the shield box, and also to provide an image formation apparatus having the shield box.SOLUTION: A shield box 20 having a plurality of heat generating components 25, 28 and so forth arranged therein comprises: a main wall surface 20b provided with a plurality of air intake ports 35, 38 and so forth in a manner corresponding to the plurality of heat generating components; and an exhaust fan 31 for discharging internal air. The distances from the main wall surface 20b to the plurality of heat generating components differ depending on the heat generating components. The plurality of air intake ports are formed at positions immediately above the corresponding heat generating components, or at positions displaced away from the positions immediately above them when seen from the exhaust fan 31. The distances between the positions of the air intake ports and the positions immediately above the corresponding heat generating components become greater as the distances from the main wall surface 20b to the corresponding heat generating components increase.

Description

  The present invention relates to an image forming apparatus such as a printer or a FAX, and a shield box disposed in the casing. More specifically, the present invention relates to a shield box that accommodates components that generate a large amount of heat and an image forming apparatus having the shield box.

  2. Description of the Related Art Conventionally, in an electronic apparatus such as an image forming apparatus, a plurality of electronic components such as a printed circuit board are collectively stored in a box, and the entire box is stored in a housing of the image forming apparatus. This box is used to suppress the emission of electromagnetic noise generated by electronic components to the outside, and is called a shield box. Since electronic components housed in the shield box include those that generate heat, they are usually cooled by ventilating the shield box. For example, an air inlet is provided on one end side of the shield box and an exhaust fan is provided on the other end side so that air flows through the entire shield box.

  In order to efficiently cool such heat-generating components, a technique in which the arrangement of fans and ducts has been devised has been disclosed (see, for example, Patent Document 1). For example, Patent Literature 1 discloses a cooling device in which a ventilation duct that opens toward each heat generating component is provided in a blower duct disposed in a device casing. According to this document, the air blown out from the vent hole can cool the heat-generating component more efficiently than a branch formed in the duct.

JP 2000-252675 A

  However, even if a duct as described in Patent Document 1 is provided outside the shield box, the heat-generating components in the shield box cannot be efficiently cooled. In the shield box of the image forming apparatus, parts that generate particularly large heat are arranged so as to be scattered at a plurality of locations on the substrate, and other parts need to be cooled to some extent. Therefore, providing the duct in the shield box so that the necessary air volume can be secured by the duct as described in Patent Document 1 described above results in a large shield box and a complicated structure. Therefore, it is not preferable.

  The present invention has been made to solve the above-described problems of the prior art. That is, the subject is to provide a shield box capable of appropriately cooling electronic components including heat generating components arranged inside the shield box without increasing the size of the device, and an image forming apparatus having the shield box. There is to do.

  The shield box of the present invention, which has been made for the purpose of solving this problem, is a shield box in which a plurality of heat generating components are arranged, and a plurality of air inlets are provided corresponding to the plurality of heat generating components. It has a main wall and an exhaust fan that exhausts the internal air. The distance from the main wall of the heat generating parts differs depending on the heat generating parts, and the air intakes are located directly above the corresponding heat generating parts or exhaust It is formed at a position far from the position directly above the fan, and the distance between the inlet position and the position directly above the corresponding heat generating component is larger as the distance from the main wall of the corresponding heat generating component is larger. It ’s a big one.

  According to the shield box of the present invention, outside air is taken in from a plurality of intake ports, and each part in the shield box is cooled and exhausted by the exhaust fan. Since a plurality of air inlets are provided corresponding to the plurality of heat generating parts arranged inside the shield box, each heat generating part hits relatively low-temperature air immediately after being input from the air inlet. In addition, the position of the intake port is determined according to the distance between the main wall surface on which the intake port is provided and the heat generating component. When the heat generating component is far from the main wall surface, the intake port is shifted to the far side as viewed from the exhaust fan from the position directly above the heat generating component, that is, arranged upstream of the air flow. Therefore, since the air taken in from the intake port reliably hits the heat generating component by the air flow from the exhaust fan, the heat generating component can be appropriately cooled. Therefore, according to the present invention, it is possible to appropriately cool the electronic components including the heat generating components arranged inside the shield box without increasing the size of the apparatus.

Furthermore, in the present invention, the main wall surface has a side end surface provided so as to intersect with the main wall surface, and the exhaust fan is attached to the side end surface so as to discharge air in a direction intersecting the side end surface. It is desirable.
If it becomes like this, the exhaust direction by an exhaust fan will become a direction substantially parallel to a main wall surface. Therefore, the air that has entered from the intake port does not travel linearly, but travels in a direction that is different from the input direction. Therefore, it is possible to cool not only the corresponding heat generating parts but also a wide range in the shield box.

Furthermore, in the present invention, the shield box has a substrate that is arranged opposite to the main wall surface and has a plurality of heat generating components mounted on the main wall surface side, and the distance from the top substrate of the plurality of heat generating components is the heat generating component. It is desirable that the substrate is arranged so that a virtual surface obtained by extending the plate surface on the main wall surface side to the side end surface crosses the opening range of the exhaust fan.
If it becomes like this, the exhaust_gas | exhaustion by an exhaust fan will flow in the direction along the board surface of a board | substrate. Accordingly, it is possible to appropriately cool components on the board including components other than the heat generating components. Since the heat generating component is mounted on the main wall surface side of the board, it is arranged to directly face the air inlet provided on the main wall surface. Therefore, the air input from the intake port can cool the heat generating component appropriately.

Furthermore, in the present invention, it is desirable that the opening area of the plurality of intake ports be larger as the heat generation amount of the corresponding heat generating component is larger.
If it becomes like this, more air volume will be supplied to the heat-generating component with a large calorific value. Therefore, it is possible to reliably cool even a heat generating component having a large heat generation amount.

Furthermore, the present invention is an image forming apparatus in which any one of the above-described shield boxes and an image forming unit is housed in a housing, and the shield box has a main wall facing the inside of the outer plate of the housing. The image forming apparatus is also arranged in the housing so that a vent hole is formed in a region of the outer plate of the housing facing the air inlet of the main wall surface.
An electronic component for controlling the image forming unit of the image forming apparatus also includes a heat generating component having a large heat generation amount. If such an electronic component is housed in the shield box of the present invention and housed in the housing, emission of electromagnetic noise can be suppressed and adverse effects due to heat generation can be reliably suppressed. In particular, if a vent is formed in a region of the outer plate of the casing that faces the inlet of the shield box, the air sucked into the shield box is supplied from outside the casing, which is more preferable. .

Further, in the image forming apparatus of the present invention, an exhaust port is formed at a position different from the vent hole on the outer plate of the casing, and the air exhausted by the exhaust fan is provided inside the casing and outside the shield box. It is desirable to provide a duct for guiding the air to the exhaust port.
If it becomes like this, the exhaust_gas | exhaustion discharged | emitted from a shield box will be discharged | emitted appropriately so that other members may not be affected.

  According to the shield box of the present invention and the image forming apparatus having the shield box, it is possible to appropriately cool the electronic components including the heat generating components arranged inside the shield box without increasing the size of the apparatus.

It is side surface sectional drawing which shows the image forming apparatus which concerns on this form. 1 is a rear sectional view showing an image forming apparatus according to the present embodiment. It is explanatory drawing which shows the attachment state of the components to a controller board | substrate. It is explanatory drawing which shows the difference of the opening area of an inlet port.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best mode for embodying the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, the present invention is applied to an electrophotographic image forming apparatus.

  As shown in FIG. 1, the image forming apparatus 10 of this embodiment has an image forming unit 12 inside a housing 11. The configuration of the image forming unit 12 may be any known one. Further, the image forming apparatus 10 according to the present embodiment includes an operation panel 14 that receives user instruction input, a paper cassette 15 that can be attached to and detached from the housing 11, and the like on the right side in the drawing. That is, in this figure, the right side is the front surface 11a of the casing 11, which is an operation position where the user stands. The left side in the figure is the back surface 11b of the apparatus.

  As shown in FIGS. 1 and 2, a flat box-shaped shield box 20 is disposed along the back surface 11 b in the housing 11 of the image forming apparatus 10 of this embodiment. The shield box 20 of this embodiment is one in which electronic components such as the controller board 21 are housed. The controller board 21 and the like are for controlling each part of the image forming unit 12. That is, the image forming unit 12 performs image formation while exchanging electrical signals with each electronic component in the shield box 20. The exchange of electrical signals here includes not only signals such as control command signals and detection signals, but also power supply.

  The shield box 20 of this embodiment is a metal box-like member, for example, and is intended to suppress the emission of electromagnetic noise from internal electronic components. FIG. 2 is a diagram illustrating an arrangement viewed from the left side of FIG. 1, that is, from the back side of the image forming apparatus 10. However, FIG. 1 shows only some of the components (25 to 28 in FIG. 2) arranged in the shield box. Note that vents 11 c are provided on the back surface 11 b of the outer plate of the housing 11 at least at various locations within the range facing the shield box 20.

  The shield box 20 of this embodiment has a flat rectangular parallelepiped box shape. The shield box 20 is disposed so that a substantially square large-area surface of the outer surface of the shield box 20 is parallel to the back surface 11 b of the housing 11. A controller substrate 21 is fixed to a surface parallel to the rear surface 11b of the housing 11 (hereinafter referred to as a main bottom surface 20a). As shown in FIGS. 1 and 2, the controller substrate 21 has a size that occupies almost the entire main bottom surface 20a, and is arranged substantially parallel to the main bottom surface 20a. The controller boards 21 are attached close to the main bottom surface 20a so as not to contact each other.

  In addition, the surface of the shield box 20 that faces the main bottom surface 20a (hereinafter referred to as the main wall surface 20b) is arranged in close proximity to the rear surface 11b of the housing 11 as shown in FIG. Yes. There is nothing blocking the air flow between the main wall surface 20b and the back surface 11b.

  Furthermore, various components are attached to the surface 21 a (surface facing the main wall surface 20 b of the shield box 20) of the controller substrate 21. Some parts are mounted directly on the controller board 21, but others are mounted slightly apart from the controller board 21 using a support or the like (see FIG. 3). Examples of components that are separately mounted in this manner include a sub board, an option board, and an HDD. Parts may also be attached to the back surface of the controller board 21.

  Among the electronic components attached to the controller board 21 and the like and arranged in the shield box 20, those that generate a large amount of heat are included. However, parts that generate a large amount of heat rarely occupy more than half the area of the controller board 21. In addition, when there are a plurality of parts that generate a large amount of heat, they are rarely arranged close to each other and are often distributed at various places. In addition, all the parts that generate a large amount of heat are arranged on the surface 21 a of the controller board 21.

  Of the electronic components arranged in the shield box 20, examples of components that generate large amounts of heat include a CPU, an ASIC (Application Specific Integrated Circuit), a control chip, and a coil and a transistor in a power supply circuit. In addition, there are cases where components that generate large amounts of heat are included in the sub-board, the option board, or the HDD.

  1 and 2 show that heat generating components 25 to 28 having relatively large heat generation are attached in the shield box 20. Among these, the heat generating components 25 to 27 are directly attached to the controller substrate 21, and the heat generating component 28 is attached slightly away from the controller substrate 21.

  FIG. 3 shows an example of a component mounting configuration on the controller board 21. This figure is an example of component arrangement different from those in FIGS. Parts 41 and 42 in FIG. 3 are examples that are directly attached to the controller board 21. The HDD 43 is attached to a position slightly away from the controller board 21 by a support 44 with the controller board 21 as a base.

  That is, the distances between the components arranged on the controller board 21 and the main wall surface 20b of the shield box 20 are not uniform. For example, the HDD 43 in FIG. 3 is arranged at a position far from the main bottom surface 20a as compared with the components 41 and 42. That is, the HDD 43 is close to the main wall surface 20b, and the components 41 and 42 are far from the main wall surface 20b. In the example of this embodiment shown in FIGS. 1 and 2, the heat generating component 28 is disposed near the main wall surface 20b, and the heat generating components 25 to 27 are disposed at positions far from the main wall surface 20b.

  Further, as shown in FIGS. 1 and 2, an exhaust fan 31 is attached to the lower side end surface 20 c of the shield box 20. The term “below” as used herein means a portion that becomes the lower side when the casing 11 of the image forming apparatus 10 is set in a usable direction. Since the shield box 20 of this embodiment is a flat box, the side end surface 20c is a surface intersecting with these at the end of the main wall surface 20b or the main bottom surface 20a. That is, the surface to which the exhaust fan 31 is attached is an elongated surface that forms the thickness of the shield box 20. The exhaust fan 31 is attached in a direction that discharges air in a direction that intersects the side end surface 20 c of the shield box 20.

  In particular, in this embodiment, the exhaust fan 31 is provided on the main bottom surface 20a side of the side end surface 20c and in the vicinity of the corner. That is, it is the front right side when viewed in the direction of FIG. 1, and the rear right side when viewed in the direction of FIG. In this way, a virtual surface obtained by extending the surface 21 a of the controller substrate 21 toward the side end surface 20 c is disposed so as to cross the opening range of the exhaust fan 31. Note that the arrangement of the exhaust fan 31 is not limited to the position in this figure, and may be near the corner on the left back side as viewed in the direction of FIG.

  That is, the exhaust fan 31 is disposed at a right angle and downward with respect to the main bottom surface 20 a and the main wall surface 20 b of the shield box 20, and the direction of intake and exhaust is parallel to the controller board 21. Therefore, the exhaust fan 31 can suck the air inside the shield box 20 downward along the surface of the controller board 21 and discharge it to the outside of the shield box 20. In FIGS. 1 and 2, the direction of the air flow at each location is indicated by arrows.

  Further, as shown in FIG. 2, a duct 33 is provided outside the exhaust fan 31. Further, an exhaust port 34 is formed in the housing 11 at a position different from the vent port 11 c facing the shield box 20. The duct 33 serves as a ventilation path from the exhaust fan 31 toward the exhaust port 34. Accordingly, the air discharged from the shield box 20 by the exhaust fan 31 is guided to the exhaust port 34 through the duct 33 and is discharged to the outside of the housing 11.

  In the shield box 20 of the present embodiment, the main wall surface 20b is provided with intake ports 35 to 38 as shown in FIG. These air inlets 35 to 38 are arranged to face the air vent 11c on the back surface 11b, and can circulate outside air. The shield box 20 has no place where air can enter and exit other than the intake ports 35 to 38 and the exhaust fan 31. Therefore, when the exhaust fan 31 is driven to exhaust the air in the shield box 20 to the outside, the outside air flows into the shield box 20 from the intake ports 35 to 38. As a result, air can flow inside the shield box 20 and components and the like disposed in the shield box 20 are cooled.

  The exhaust fan 31 is disposed not near the main wall surface 20b where the intake ports 35 to 38 are formed, but near the main bottom surface 20a. The exhaust fan 31 sucks the air in the shield box 20 downward along the surface of the controller board 21. That is, the opening surfaces of the intake ports 35 to 38 and the intake direction sucked out from the shield box 20 by the exhaust fan 31 are approximately parallel to each other. Therefore, by driving the exhaust fan 31, the outside air flowing from the intake ports 35 to 38 proceeds downward from the main wall surface 20 b side to the main bottom surface 20 a side and along the controller board 21. Furthermore, since the exhaust fan 31 is provided at the corner of the side end face 20c, the air flows rightward in FIG.

  And in this form, the inlets 35-38 are each provided corresponding to arrangement | positioning of each heat-emitting components 25-28. That is, one intake port is provided for each heat generating component. Further, the shield box 20 of the present embodiment is characterized by the positions and sizes of the intake ports 35 to 38.

  First, the positions of the intake ports 35 to 38 will be described. As described above, the distance between the heat generating components and the controller board 21 is not uniform. In view of this, the intake ports 35 to 38 are respectively arranged at positions where the air flow is appropriately applied to the heat generating components 25 to 28. The air intake port corresponding to the heat generating component disposed near the main wall surface 20b, which is the surface on which the air intake port is provided, is provided at a position substantially facing the heat generating component. On the other hand, the air inlet corresponding to the heat generating component disposed on the main bottom surface 20a side away from the main wall surface 20b is disposed at a position shifted from the position facing the heat generating component to the side far from the exhaust fan 31 (upstream side with respect to the airflow). Has been. The distance between the position directly above the part and the position of the intake port is larger as the distance from the main wall surface 20b of the part is larger.

  Explaining in the example of FIG. 3, the exhaust fan 31 is arranged toward the main bottom surface 20a, and is disposed rightward in the drawing on the right side in the drawing. Therefore, when the exhaust fan 31 is driven, air flows from left to right and from top to bottom as indicated by arrows in the figure. An air inlet 46 corresponding to the HDD 43 at a position close to the main wall surface 20 b is provided almost immediately above the HDD 43. Further, the air inlet 47 corresponding to the component 41 located far from the main wall surface 20b is provided on the upstream side of the component 41 on the upstream side (on the left side in the drawing from directly above).

  By doing so, the air flowing into the shield box 20 from the air inlet 46 first hits the HDD 43 located nearby and cools the HDD 43. Then, it flows in the right direction in the figure with the exhaust fan 31 and cools the parts on the way. Further, the air flowing in from the intake port 47 is drawn by the exhaust fan 31 and proceeds obliquely downward, and hits the component 41. First, the component 41 is cooled. Then it flows to the right in the figure. Accordingly, any air can cool the heat-generating parts before the temperature rises, and can cool the other parts in the subsequent flow.

  In the example shown in FIG. 2 as well, the positional relationship between the heat generating components 25 to 28 and the exhaust fan 31 is considered in the plane, and the positions of the intake ports 35 to 38 are determined. Among these heat generating components, the heat generating components 25 to 27 are directly attached to the controller board 21. Therefore, the intake ports 35 to 37 corresponding to these are shifted to the upstream side in the air flow direction from directly above the parts, and are arranged on the side far from the exhaust fan 31.

  On the other hand, the heat generating component 28 is attached to a position in the shield box 20 that is slightly separated from the controller board 21 and relatively close to the main wall surface 20b. Therefore, the air inlet 38 corresponding to the heat generating component 28 is disposed at a position substantially opposite to the heat generating component 28. The arrangement of the intake port 38 may be farther from the exhaust fan 31 than immediately above the heat generating component 28, but is not as far away from the relationship between the intake ports 35 to 37 and the heat generating components 25 to 27.

  In addition, the distance with respect to the main wall surface 20b of a component here is the distance between the main wall surface 20b and the top part of each component. For this reason, the distance from the main wall surface 20b may be different even between the components directly attached to the controller board 21.

  As described above, since the intake ports 35 to 38 are provided at positions corresponding to the heat generating components 25 to 28, the air flowing from the intake ports 35 to 38 surely hits the heat generating components 25 to 28, respectively. Therefore, the heat generating components 25 to 28 are reliably cooled by the relatively low temperature air immediately after the inflow. Furthermore, since the air flowing in from the intake ports 35 to 38 entrains the air in the shield box 20 and flows out from the exhaust fan 31, other portions in the shield box 20 are also cooled.

  Next, the opening area of the intake ports 35 to 38 will be described. The amount of heat generated by the heat generating components 25 to 28 is different for each component. For example, in this embodiment, the heat generation amount of the heat generating component 25 is large, and the heat generation amount of the heat generating component 27 is small. The heat generation amount of the heat generating components 26 and 28 is between these. The heat generation amount of the heat generating components 25 to 28 and the opening area of the corresponding intake ports 35 to 38 have a certain relationship. That is, the opening area of the intake port is larger as the heat generation amount of the corresponding heat generating component is larger. The opening area of the intake port is determined to be proportional to the amount of heat generated by the corresponding heat generating component.

The opening areas A35 to A38 of the intake ports 35 to 38 of the present embodiment are obtained by the following formulas 1 to 4 based on the heat generation amounts Q25 to Q28 of the heat generating components 25 to 28.
However, A = A35 + A36 + A37 + A38
Q = Q25 + Q26 + Q27 + Q28
A35 = A × Q25 / Q (Formula 1)
A36 = A × Q26 / Q (Formula 2)
A37 = A × Q27 / Q (Formula 3)
A38 = A × Q28 / Q (Formula 4)

  For example, this embodiment shows an example in which the heat generation amounts Q25 to Q28 of the heat generating components 25 to 28 are 40%, 25%, 10%, and 25%, respectively, with respect to the total heat generation amount Q. Therefore, the opening areas A35 to A35 of the intake ports 35 to 38 are set to 40%, 25%, 10%, and 25% with respect to the total area A. As a result, the cooling air with the air volume corresponding to the heat generation amount of each heat generating component reliably hits each heat generating component.

  As described above in detail, in the image forming apparatus 10 of the present embodiment, the heat generating components 25 to 28 that generate large amounts of heat are dispersed in the shield box 20, and the air inlets on the main wall surface 20 b corresponding to each. 35-38 are formed. The intake ports 35 to 38 are arranged away from the exhaust fan 31 from the position immediately above according to the distance from the main wall surface 20b. In addition, the opening area of the intake ports 35 to 38 is determined in accordance with the heat generation amount of the heat generating component. Therefore, the cooling air can be surely applied to each of the heat generating components 25 to 28 without increasing the capacity of the exhaust fan 31, and the inside of the shield box 20 can be reliably cooled with an appropriate air volume. . As a result, the image forming apparatus can appropriately cool the heat generating components arranged inside the shield box without increasing the size of the apparatus.

In addition, this form is only a mere illustration and does not limit this invention at all. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof.
For example, the shape of the shield box 20 is not limited to a flat box shape, but may be any shape that can appropriately accommodate the controller board 21. The exhaust fan 31 is not limited to the lower surface of the shield box 20, but may be provided on any surface that intersects the main bottom surface 20 a and the main wall surface 20 b, but exhausts in a direction substantially parallel to the controller substrate 21. It is preferable to arrange so as to. Further, the lower surface is preferable in order to easily discharge dust and the like. The shield box may be for preventing electromagnetic noise from entering.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 11 Case 11c Vent 12 Image forming part 20 Shield box 20a Main bottom surface 20b Main wall surface 20c Side end surface 21 Controller board 25-28 Heating part 31 Exhaust fan 33 Duct 34 Exhaust port 35-38 Inlet port

Claims (6)

In a shield box in which multiple heat-generating parts are arranged,
A main wall surface provided with a plurality of air inlets corresponding to the plurality of heat generating components;
An exhaust fan for exhausting the internal air,
The distance from the main wall surface of the plurality of heat generating parts varies depending on the heat generating parts,
The plurality of intake ports are formed at a position directly above the corresponding heat generating component, or at a position shifted farther from the position directly above when viewed from the exhaust fan,
The shield box characterized in that the distance between the position of the intake port and the position directly above the corresponding heat generating component increases as the distance from the main wall surface of the corresponding heat generating component increases. The shield box according to claim 1,
A side end surface provided at one end of the main wall surface so as to intersect the main wall surface;
The shield fan, wherein the exhaust fan is attached to the side end face in a direction to discharge air in a direction intersecting the side end face. The shield box according to claim 2,
The substrate is disposed in the shield box so as to face the main wall surface, and the plurality of heat generating components are mounted on the main wall surface side,
The distance from the substrate of the top of the plurality of heat generating components varies depending on the heat generating components,
The shield box, wherein the substrate is arranged such that a virtual surface obtained by extending a plate surface on the main wall surface side toward the side end surface crosses an opening range of the exhaust fan. In the shield box according to any one of claims 1 to 3,
The shield area, wherein the opening area of the plurality of intake ports is larger as the heat generation amount of the corresponding heat generating component is larger. An image forming apparatus comprising: a shield box according to any one of claims 1 to 4; and an image forming unit housed in a housing.
The shield box is disposed in the casing so that the main wall faces the inner side of the outer plate of the casing;
An image forming apparatus, wherein an air vent is formed in a region of the outer plate of the housing facing the air inlet on the main wall surface. The image forming apparatus according to claim 5,
An exhaust port is formed at a position different from the vent hole on the outer plate of the housing,
2. An image forming apparatus according to claim 1, wherein a duct for guiding the air exhausted by the exhaust fan to the exhaust port is provided inside the casing and outside the shield box.

Images