JP2010039202A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the cooling efficiency of an air duct without causing an increase in manufacturing cost, aggravation of an apparatus operation noise, an increase in power consumption and upsizing of the product. <P>SOLUTION: An auxiliary air suction opening 56 is formed in a casing 53. The auxiliary air suction opening 56 is opened to the outside of the apparatus, and is configured to introduce the external air utilizing a negative pressure generated in response to the air supply by a blower fan 50. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer having a function of forming an image on a recording material such as a sheet.

  The image forming device should suppress the temperature rise and prevent the thermal effects on other elements such as self-heating of motors and various electronic parts, heat generation due to friction at the drive unit, thermal effect of the fixing unit, etc. There are many points. As a means for realizing this, a method of providing a cooling air passage and cooling the heat source by blowing air from a fan is generally used. On the other hand, since image forming devices are also required to be compact, reduce power consumption, and reduce operating noise, it is necessary to minimize the number of fans used and to use the same air path as much as possible. It becomes.

The air path is formed by arbitrarily connecting the following two basic configurations as necessary.
Series air path: The air is cooled through a plurality of heat sources in order.
Parallel air path: The air is diverted to a plurality of heat sources and cooled.

  A series air path is a structure generally used when heat sources are close to each other. Since 100% of the air volume at the inlet of the air passage can be supplied to the heat source, it is suitable for cooling a heat source with a large amount of heat generation. On the other hand, the cooling air temperature increases toward the downstream side of the air passage, so the cooling capacity decreases. Tend to.

  The parallel air path is a configuration used when the heat sources are separated from each other. The amount of air that can be supplied to each heat source is reduced to about “1 / the number of heat sources” of the fan's blowing capacity, so that the cooling capacity for each heat source is reduced by the amount of branching.

In the image forming apparatus, the air path is designed in accordance with the characteristics of each heat source in consideration of the arrangement, the amount of heat generation, the heat dissipation, and the like. Then, a fan having the minimum necessary air blowing capacity that can satisfy the function while the cooling efficiency is maximized is selected. The position where the fan is provided from the inlet to the outlet of the air passage is appropriately determined according to the device configuration, fan characteristics, and the like.
JP 2003-152924 A JP 2003-241624 A JP 2004-37685 A

  However, when the desired cooling performance cannot be satisfied due to the optimization of the air path, conventionally, it has been necessary to improve the heat radiation performance of the heat source or to change to a fan having a higher blowing capacity. If that wasn't enough, we had to revise the airway structure and add new fans.

  As a result, there has been a concern that it may cause adverse effects such as an increase in product cost, deterioration in device operation sound, increase in power consumption, and increase in product size.

  In recent years, there has been a demand for a further cooling efficiency improvement method as the cost of image forming apparatuses has been reduced and at the same time the demand for environmental protection has increased.

The present invention has been made in view of the circumstances as described above, and improves the cooling efficiency of the air passage without causing an increase in product cost, a deterioration in apparatus operating sound, an increase in power consumption, and an increase in product size. For the purpose.

In order to achieve the above object, the present invention provides:
A heat generating part that generates heat;
A blowing means for supplying air to the heat generating part;
A casing member provided so as to surround the heat generating portion, and has a ventilation opening for introducing air supplied from the blowing means, and an exhaust opening for exhausting air inside the casing member, A casing member that forms an air passage from the blower opening to the exhaust opening;
In an image forming apparatus for forming an image on a recording material,
The casing member is an auxiliary intake opening provided to open to the outside of the apparatus, and the auxiliary intake opening that introduces outside air using negative pressure generated when air is supplied by the air blowing means It has the part.

  According to the present invention, it is possible to increase the cooling efficiency of the air passage without causing an increase in product cost, deterioration in device operation sound, increase in power consumption, and increase in product size.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately changed according to the configuration of the apparatus to which the invention is applied and various conditions. It is not intended to limit the scope to the following embodiments.

  The present invention relates to an improvement in cooling efficiency of in-machine cooling airflow in an image forming apparatus.

  Example 1 of the present invention will be described below.

  FIG. 6 is a cross-sectional view showing a schematic configuration of an image forming apparatus to which the present invention is applicable.

  Reference numeral 1 denotes a printer main body. In order to form a primary image of a total of four colors, yellow, magenta, cyan, and black (hereinafter abbreviated as Y, M, C, and K) on the upper portion of the printer main body 1. The engine part (image forming part) is laid out.

  Print data transmitted from an external device such as a PC is received by a controller that controls the printer main body 1, and is output as write image data to the laser scanners 10a and 10b corresponding to each color. The laser scanner irradiates the photosensitive drum 12 with a laser and draws an optical image according to the written image data. In the image forming apparatus of the present embodiment, an optical image is written by two laser scanners, a first scanner 10a that performs laser irradiation for yellow and magenta, and a second scanner 10b that performs laser irradiation for cyan and black. .

  The engine portion includes a toner cartridge 15 for supplying toner and a process cartridge for forming a primary image (indicated by Y, M, C, and K in the figure) at each of the Y, M, C, and K stations. It consists of.

The process cartridge includes a photosensitive drum 12, a charger 13, a developing device 14, and a cleaner (not shown). Here, the charger 13 is for uniformly charging the surface of the photosensitive drum 12. In addition, the developing device 14 is a toner image to be transferred to the intermediate transfer belt 34, an electrostatic latent image created by the laser scanner 10 drawing an optical image on the surface of the photosensitive drum 12 charged by the charger 13. It is intended to develop into The cleaner is for removing the toner remaining on the photosensitive drum 12 after transferring the toner image.

  A primary transfer roller 33 for transferring the toner image developed on the surface of the photosensitive drum 12 to the intermediate transfer belt 34 is disposed at a position facing the photosensitive drum 12.

  The toner image (primary image) transferred to the intermediate transfer belt 34 is retransferred onto the recording material by a secondary transfer roller 31 that also serves as a driving roller for the intermediate transfer belt and an opposing secondary transfer outer roller 24. The The toner remaining on the intermediate transfer belt 34 without being transferred to the recording material in the secondary transfer portion is collected by the intermediate transfer belt cleaner 18.

  The feeding unit 20 is located in the uppermost stream of the recording material conveyance, and is provided in the lower part of the apparatus. When the recording material loaded and stored in the feeding tray 21 is fed by the feeding unit 20, the recording material passes through the vertical conveyance path 22 and is conveyed downstream. The longitudinal conveyance path 22 includes a registration roller pair 23, where final skew correction of the recording material and image writing and recording material conveyance timing in the image forming unit are performed.

  A fixing device 25 for fixing the toner image on the recording material as a permanent image is provided on the downstream side of the image forming unit, and a discharge roller for discharging the recording material from the printer main body 1 on the downstream side. A discharge conveyance path to 26 is provided. The recording material discharged by the discharge roller 26 is received by a discharge tray 27 provided outside the printer 1.

  As with a general image forming apparatus, the image forming apparatus according to the present embodiment also has a number of elements (heat generating portions and heat sources) that generate heat during the printing operation, and among them, the product quality is affected. The location is dealt with by providing an air passage for cooling and heat insulation.

  For example, a cooling air path is set to prevent the electric elements mounted on the power supply board and control board for driving and controlling the image forming apparatus and the video board for processing the printed image from exceeding the standard temperature. ing. In addition, a cooling air passage for keeping the ambient temperature of the engine portion where the process cartridges for each color of YMCK are arranged below a predetermined temperature, a heat insulation air passage for preventing heat generated by the fixing unit from affecting the toner cartridge, etc. Is set.

  Of these air paths, the cooling air paths for the control board and the video board will be described in detail as an application example of the present invention.

  In the image forming apparatus according to the present embodiment, the control board and the video board are laid out side by side on the lower back side of the image forming apparatus, and the two are connected by a single air path to be cooled. Yes. Various electrical elements such as a CPU for controlling the image forming apparatus are mounted on the control board. Similarly, a CPU necessary for image processing and transmitted image data are mounted on the video board. A hard disk for storing the battery is mounted and connected. In addition, since the kind of heat source is not the essence of the present invention, in the following description, the control board is generalized as the first heat source 51 and the video board is expressed as the second heat source 52. Here, the second heat source 52 corresponds to a heat generating portion.

  A schematic representation of the above-described cooling air passage is as shown in FIG. FIG. 1 is a cross-sectional view showing a schematic configuration of a cooling air passage of the present embodiment.

The blower fan 50 disposed between the first heat source 51 and the second heat source 52 blows air from the intake opening 54 to the exhaust opening 57 in the cooling air passage. Here, the blower fan 50 corresponds to a blower that supplies air to the second heat source 52.

  The wind (air) introduced from the intake opening 54 by the suction action of the blower fan 50 first cools the first heat source 51. The wind that has cooled the first heat source 51 is then sucked into the blower fan 50 and introduced into the blower opening 55. Then, the air is supplied from the blower opening 55 to the second heat source 52, and after cooling the second heat source 52, the air is exhausted from the exhaust opening 57 that exhausts the air inside the casing 53 (inside the casing member). ).

  FIG. 2 is a cross-sectional view showing a schematic configuration of an auxiliary intake opening 56 provided in a casing 53 as a casing member in the present embodiment.

  An auxiliary intake opening 56 that opens to the outside air (opens to the outside of the apparatus) is provided in the casing 53 that forms an air passage surrounding the second heat source 52. The auxiliary intake opening 56 is provided on the wall surface 53 a disposed along the flow (air blowing) of air supplied by the blower fan 50 among the wall surfaces constituting the casing 53, and is supplied by the blower fan 50. It is provided near the downstream of the air blowing direction. In the auxiliary intake opening 56, a negative pressure space B is generated by the flow of wind generated by the blower fan 50, and a louver having a cross-sectional shape as shown in FIG. 2 as an inclined portion so that outside air is introduced into the casing 53. 56a is adopted. As shown in FIG. 2, the louver 56 a is provided so as to be gradually inclined inside the casing 53 from the upstream side to the downstream side of the auxiliary intake opening 56 with respect to the blowing direction of the blower fan 50, and air is supplied by the blower fan 50. As a result, negative pressure is generated. As described above, in the auxiliary intake opening 56 of the present embodiment, outside air is introduced using the negative pressure generated when air is supplied by the blower fan 50.

  Next, the positional relationship between the blowing opening 55, the auxiliary intake opening 56, and the exhaust opening 57 with respect to the casing 53 and the effects thereof will be described.

  The cross-sectional area of the casing 53 (the cross-sectional area of the space surrounded by the wall surface of the casing 53 (inside the casing)) is a cross section substantially parallel to the blower opening 55, that is, a cross section substantially perpendicular to the blowing direction of the blower fan 50. The opening area of the blower opening 55 is secured at least twice. As described above, the auxiliary intake opening 56 is disposed in the vicinity of the air blowing fan 50 in the vicinity of the air blowing direction on the surface along the air blowing direction.

  On the other hand, the exhaust opening 57 is arranged on the projection extension of the blower opening 55 or at a position away from the area C adjacent thereto with respect to the blowing direction by the blower fan 50. This is a position other than the virtual area and in the vicinity of the virtual area when the ventilation opening 55 is projected in the blowing direction of the blower fan 50 and the following virtual area (corresponding to the area C) is considered. It is a position other than. The virtual region is a projected opening 55a formed on the inner wall surface of the casing 53 located downstream of the blowing fan 50 in the blowing direction of the blowing fan 50 when the blowing opening 55 is projected in the blowing direction of the blowing fan 50 (the hatched portion in FIG. 1). ) And the blower opening 55.

  Such a layout produces the following effects on the wind flow.

The cooling air supplied from the blowing opening 55 and the outside air introduced from the auxiliary intake opening 56 are blocked by the inner wall of the casing 53 located downstream in the blowing direction. Then, it flows into the upper part of the casing where the internal pressure is kept low by the exhaust opening 57. This flow forms a spiral flow indicated by A in FIG. 1 inside the casing, and the cooling air supplied from the blower opening 55 and the outside air introduced from the auxiliary intake opening 56 are stirred and mixed with each other. . The cooling air whose temperature has been reduced by mixing with the outside air cools the second heat source 52 while drawing the spiral flow described above, and is sequentially exhausted from the exhaust opening 57 to the outside of the machine. The outline of the change of the ventilation temperature in these series of processes is shown in FIG.

  As can be seen from FIG. 3, the cooling efficiency of the air passage can be increased by the mechanism (configuration) described above.

  Here, in the image forming apparatus of the present embodiment, the ventilation opening 55, the auxiliary intake opening 56, and the exhaust opening 57 are laid out so as to be distributed to different positions in the product height direction. Therefore, when the blower fan 50 is not driven, air warmed by the second heat source 52 is discharged from the exhaust opening 57 due to the natural convection effect, and accordingly, cold outside air is discharged from the auxiliary intake opening 56. Inflow. Due to this effect, in a situation where the second heat source 52 generates little heat, for example, when the image forming apparatus is in a standby state or a sleep state, the second heat source 52 is kept below the standard temperature without driving the blower fan 50. Can keep.

  In the present embodiment, the ventilation opening 55 and the auxiliary intake opening 56 are disposed below the exhaust opening 57, but the same effect can be obtained even if this is reversed. However, since the exhaust opening 57 usually has a larger opening area than the auxiliary intake opening 56, the arrangement of the present embodiment can produce smooth natural convection. Further, it is possible to prevent the heat generated by the second heat source 52 from flowing into the first heat source 51 through the air blowing opening 55.

  In the first embodiment, a configuration in which a flow of a vortex wind is created inside the casing by using the interaction between the layout of the ventilation opening, the auxiliary intake opening, and the exhaust opening and the casing shape, and the cooling air and the outside air are mixed is described. did. However, the present invention is not limited to this configuration. Example 2 shows an example in which cooling air and outside air are smoothly mixed by another method. Since the configuration of the image forming apparatus to which the invention is applied is the same, the description thereof is omitted, and elements similar in function to those of the first embodiment are given the same symbols as those of the first embodiment in the drawing.

  A schematic representation of the cooling air passage of the present embodiment is as shown in FIG. FIG. 4 is a cross-sectional view showing a schematic configuration of the cooling air passage of the present embodiment.

  The blower fan 50 disposed in the relay air passage 59 connecting the first heat source 51 and the second heat source 52 blows air from the intake opening 54 to the exhaust opening 57 in the air passage. The The wind introduced from the intake opening 54 by the suction action of the blower fan 50 first cools the first heat source 51. Thereafter, the air is supplied from the blower opening 55 to the second heat source 52 via the relay air passage 59, cooled, and then exhausted from the exhaust opening 57 to the outside of the apparatus.

  In the relay air passage 59, an auxiliary intake opening 56 that is open to the outside air is provided in the vicinity of the downstream of the blowing fan 50 in the blowing direction, as in the first embodiment. As in the first embodiment, as shown in FIG. 2, a negative pressure is positively generated in the auxiliary intake opening 56 by the flow of air generated by the blower fan 50 and the outside air is introduced into the casing. A louver having a cross-sectional shape is provided.

  In the relay air passage 59, further downstream of the auxiliary intake opening 56, as a stirring means for mixing the cooling air sent from the blower fan 50 and the outside air introduced from the auxiliary intake opening 56. A stirring member 58 is provided.

In the present embodiment, a spiral partition plate is installed as the stirring member 58, and thereby a vortex in the blowing direction is generated in the cooling air to obtain an air mixing effect. Normally, the wind generated by an axial fan winds a gentle vortex coaxial with the rotation axis of the propeller. Therefore, the spiral shape of the partition plate (stirring member 58) is set in the direction opposite to the direction of the vortex, thereby stirring. Increases the effect. Cooling air that has been mixed and made uniform in temperature is supplied to the second heat source 52 from the air blowing opening 55 that hits the outlet of the relay air passage 59.

  In addition, in the structure of Example 2 shown above, although stirring mixing of cooling air was performed using the spiral partition plate as a stirring means, this invention is not limited to this. If a shape capable of generating a turbulent flow in the wind flow is provided in the middle of the wind path to some extent, the same effect can be obtained.

(Other examples)
FIG. 5 is a cross-sectional view showing a schematic configuration of a cooling air passage in another embodiment.

  The present invention is not limited to the configurations of the first and second embodiments described above, and various applications are conceivable.

  First, in any of the examples, the image forming apparatus described in the above embodiment adopts a configuration in which the cooling air supplied from the blower fan 50 and the outside air introduced from the auxiliary intake opening 56 are stirred and mixed.

  However, the cooling air supplied by the blower fan and the outside air introduced from the auxiliary intake opening are not necessarily stirred and mixed, and the presence or absence of this configuration is not particularly limited. For example, a heat source with a large calorific value is arranged at a position where low temperature wind passes mainly even if both are not stirred and mixed and supplied to the second heat source 52 in a substantially laminar flow state. In this way, efficient cooling can be realized. Here, the heat source having a large heat generation amount is a heat sink, a coil, or the like of the heating element in the case of the electric substrate.

  In the above embodiment, the louver having a cross-sectional shape as shown in FIG. 2 is adopted for the auxiliary intake opening 56, but the configuration of the auxiliary intake opening is not limited to this. As a general theory of fluids, it is known that air flows into the air passage by negative pressure from the opening provided on the surface along the fast wind flow unless the air passage internal pressure is so high. Based on this principle, it is possible to obtain the same effect. For example, an auxiliary air passage 61 as shown in FIG. 5 may be added instead of the louver in the above-described embodiment.

  Further, the configurations of the first and second embodiments may be combined. That is, in the casing 53 of FIG. 4, the cross-sectional area of the casing 53 may be ensured at least twice the opening area of the blower opening 55 with respect to a cross section substantially parallel to the blower opening 55. Further, in the casing 53 of FIG. 4, the exhaust opening 57 is arranged on the projection extension of the blower opening 55 or at a position away from the area C adjacent thereto with respect to the blowing direction by the blower fan 50. It may be.

  Finally, in the above embodiment, the case where the blower fan 50 is disposed between the first heat source 51 and the second heat source 52 and the two heat sources are cooled by one cooling air passage has been described as an example. However, the number of target heat sources is not limited to two, and one or more heat sources may be used.

  Further, the position where the blower fan 50 is arranged is not limited to a plurality of heat sources, and may be the most upstream position of the air path. A specific example will be described below with reference to FIG.

As shown in FIG. 5, the blower fan 50 is disposed immediately after the intake opening 54, and an auxiliary air passage 61 is connected downstream of the blower fan 50 in the blowing direction. The air passage cross-sectional area downstream of the auxiliary air passage 61 in the air blowing direction is set to be larger than the cross-sectional area upstream of the point where the auxiliary air passage 61 is connected, and is designed to generate as much negative pressure as possible by air blowing. Yes. The heat source 60 is supplied with cooling air in which the air supplied from the auxiliary air passage 61 is combined with the air supplied from the blower fan 50.

  Thereby, more cooling air can be supplied to a heat source compared with the case where there is no auxiliary wind path 61. FIG. As the air path configuration, the configuration shown in FIG. 5 can be said to be the most basic form of the application example of the present invention.

(Effects of Examples)
With the configuration described in the above embodiment, when the air blowing means having the same air blowing capacity is used, the cooling efficiency can be improved as compared with the conventional in-machine cooling method.

  For example, in a cooling air passage such as a blower opening → first heat source → blower means → second heat source → exhaust opening, an auxiliary intake opening is provided between the blower means and the second heat source. The second heat source can be cooled after the temperature of the cooling air heated by the one heat source is lowered. (See FIG. 3).

  Also, in the cooling air path of the air blowing opening → the air blowing means → the heat source → the exhaust air opening, similarly, by providing the auxiliary air intake opening between the air blowing means and the heat source, the air blowing capacity of the air blowing means can be reduced from the auxiliary air intake opening. The introduced wind is added and supplied to the heat source.

  In any case, the effect of extending the cooling capacity of the cooling air passage can be obtained by providing the auxiliary intake opening between the air blowing means and the heat source. Due to this effect, it is possible to achieve a predetermined cooling performance required for the product even with a blowing means having a smaller blowing capacity. As a result, the power consumption of the image forming apparatus can be reduced, and the operation noise of the apparatus can be reduced. In addition, there is no need to improve the heat dissipation performance of the heat source, change to a fan with higher air blowing capacity, or add a new fan, so there is no increase in product cost and increase in product size. It becomes possible to increase the cooling efficiency of the air passage.

FIG. 3 is a cross-sectional view illustrating a schematic configuration of a cooling air passage in the first embodiment. FIG. 3 is a cross-sectional view illustrating a schematic configuration of an auxiliary intake opening provided in the casing of the first embodiment. In Example 1, the figure which shows the relationship between the air path position in a casing, and ventilation temperature. Sectional drawing which shows schematic structure of the cooling air path in Example 2. FIG. Sectional drawing which shows schematic structure of the cooling air path in another Example. 1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus to which the present invention can be applied.

Explanation of symbols

50 Blower Fan 52 Second Heat Source 53 Casing 55 Blower Opening 56 Auxiliary Intake Opening 57 Exhaust Opening

Claims (5)

A heat generating part that generates heat;
A blowing means for supplying air to the heat generating part;
A casing member provided so as to surround the heat generating portion, and has a ventilation opening for introducing air supplied from the blowing means, and an exhaust opening for exhausting air inside the casing member, A casing member that forms an air passage from the blower opening to the exhaust opening;
In an image forming apparatus for forming an image on a recording material,
The casing member is an auxiliary intake opening provided to open to the outside of the apparatus, and the auxiliary intake opening that introduces outside air using negative pressure generated when air is supplied by the air blowing means An image forming apparatus having a section.   The auxiliary intake opening is provided on a wall surface of the casing member that is disposed along the flow of air supplied by the air blowing means, and is provided in the vicinity of the air blowing direction downstream of the air blowing means. The image forming apparatus according to claim 1, wherein: The space surrounded by the wall surface of the casing member has a cross-sectional area twice or more that of the air blowing opening with respect to a cross section perpendicular to the air blowing direction of the air blowing means,
The exhaust opening includes a projection opening formed on an inner wall surface of the casing member that is located downstream of the air blowing means when the air blowing opening is projected in the air blowing direction of the air blowing means, and the air blowing. The image forming apparatus according to claim 1, wherein the image forming apparatus is provided at a position other than a virtual area formed between the opening and a position other than the vicinity of the virtual area.   Stirring means for stirring the air supplied by the air blowing means and the outside air introduced from the auxiliary air intake opening is provided downstream of the auxiliary air intake opening in the air blowing direction of the air blowing means. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.   The auxiliary air intake opening is an inclined portion that is provided to be gradually inclined toward the inside of the casing member from the upstream side to the downstream side of the auxiliary air intake opening with respect to the air blowing direction of the air blowing means. 5. The image forming apparatus according to claim 1, further comprising an inclined portion that generates a negative pressure when air is supplied thereto.

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