JP4508144B2 - Heat exhaust device - Google Patents

Description

  The present invention relates to a technique for preventing noise with respect to a heat exhaust apparatus using a box-type fan unit as a blowing element. This heat exhausting device is suitably used for an electrophotographic image forming apparatus such as a copying machine or a facsimile machine.

  For example, in an electrophotographic image forming apparatus such as a copying apparatus or a facsimile apparatus, a box-type fan unit is widely used as a blowing element for discharging heat generated in a fixing device to the outside. This fan unit has an axial flow composed of a flat rectangular frame-shaped mounting frame having a ventilation path from the intake surface to the exhaust surface, a rotating blade body assembled in the ventilation path, and a motor for rotating the rotating blade body. I am a fan. For this reason, the vibrations of the motor and the rotor blade may be transmitted to the surrounding parts and resonate (resonance). When the fan unit is assembled in the image forming apparatus, it is necessary to take some countermeasure for resonance.

For example, Patent Document 1 can be cited as a known resonance countermeasure. In this case, the fan unit is assembled to the duct through an elastic holding portion made of a resin material. According to this, the vibration of the fan unit can be prevented from being directly transmitted to the duct, so that the resonance of the duct can be prevented. Generation of the noise which originates can be suppressed effectively.
JP 2001-312188 A

  The present inventors are engaged in the development of a heat exhaust device including a duct, a fan unit attached to an air discharge port of the duct, and a cover case that covers an outer surface of the fan unit. In this heat exhaust device, it is planned to fix the fan unit to the air discharge port of the duct with a screw. It is also planned to cover the outer surface of the fan unit with a cover case attached to the outer surface of the duct.

  However, in the above-described mounting configuration, the vibration of the fan unit is transmitted to the cover case, and the cover case may resonate and generate noise. However, if the cover case is screwed and fixed to the duct, the resonance of the cover case can be reliably prevented, but in that case, as much troublesome screwing process increases, it takes time to assemble. As a result, there is a disadvantage that increases the manufacturing cost of the image forming apparatus.

  The present invention has been made to solve the above-described problems, and by improving the cover case mounting structure in the exhaust device, the generation of noise due to the resonance of the cover case is surely prevented. At the same time, the cover case can be quickly mounted with little effort without using screws, thereby contributing to a reduction in the manufacturing cost of the exhaust device.

The present invention as set forth in claim 1 has an air inlet and an air outlet, a duct having an air flow path between the air inlet and the air outlet, and a cylinder constituting the air outlet of the duct. A box-type fan unit that is fitted in the wall so that the rotor blades are biased toward the intake surface , and a cover case that is attached to the cylindrical wall of the air discharge port so as to cover the outer surface of the fan unit It is intended for exhaust heat equipment including
The cover case includes a main surface portion that has a plurality of openings and covers the air discharge port, and a flange that extends from the outer peripheral edge of the main surface portion toward the air discharge port. The cover case is latched and held in a retaining manner with respect to the air discharge port of the duct by engaging a locking claw formed on the cylindrical wall and a locking piece formed on the flange. , at least two positions of the flange, the tube has engaging pieces for pressure contact with the outer surface of the wall is formed, and these engaging pieces are formed projecting toward the air outlet from the outer peripheral edge of the flange, the The cover case is provided with a restricting member that protrudes from the main surface portion toward the fan unit and interferes with the rotor blade only when the fan unit is assembled in a reverse orientation of the front and back sides. Features.

  It is preferable to adopt a form in which the thickness dimension of the projecting distal end side from the flange of each engagement piece is set smaller than the thickness dimension of the proximal end side.

  It is preferable that each engagement piece has a tapered shape in which the width dimension gradually decreases as it goes to the projecting tip side from the flange.

  The cylinder wall that defines the air discharge port has a square cylindrical shape, and the flange of the cover case that is externally fitted to the cylindrical wall has a rectangular frame shape. The latching structure is provided on two sides of the flange, and the engagement pieces are provided on two sides of the flange excluding the place where the latching structure is formed. It is preferable to adopt a form in which the flange is fitted and fixed to the cylindrical wall in a state where the outer surface of the cylindrical wall is sandwiched.

In the present invention according to claim 1, when the cover case is held and fixed to the duct in a retaining shape by the latching structure, the engagement piece formed on the flange presses the cylindrical wall of the duct. The cover case can be firmly fixed to the duct without rattling. Thereby, generation | occurrence | production of the noise originating in the resonance of a cover case can be prevented reliably.
In addition, after the cover case is substantially aligned with the air outlet of the duct, the cover case can be firmly secured simply by covering the cover case with the cylindrical wall of the duct so that the latching structure and the engaging piece act. Therefore, it is possible to mount the cover case efficiently with less effort compared to the form in which the cover case is fixed to the duct by screwing. As a result, it is possible to improve the working efficiency of the assembling work of the exhaust device, which can contribute to a reduction in the manufacturing cost of the exhaust device.
In addition, if the cover case is provided with a restricting member, after mounting the fan unit and cover case to the air discharge port of the duct case, it is only necessary to check whether the rotor can rotate normally. In addition, it is possible to easily check the appropriateness of the assembly posture of the fan unit. Thereby, the incorrect assembly | attachment of the front-and-back direction of a fan unit in the manufacture process of a heat exhaust apparatus can be prevented reliably.
Furthermore, since it is possible to reliably prevent the fan unit from being assembled in a reverse posture with a simple configuration in which the restricting member is simply provided on the cover case, the heat exhausting device accompanying the provision of an erroneous assembly preventing function. This is also excellent in that the increase in the manufacturing cost and the increase in the manufacturing cost of the image forming apparatus to which the exhaust heat apparatus is applied can be minimized.

  As in the second aspect of the present invention, the thickness dimension of the projecting distal end side of each engagement piece that comes first to the cylindrical wall of the air discharge port of the duct is set to be smaller than the thickness dimension of the proximal end side. Thus, it is possible to simultaneously solve the conflicting problems of good bending deformability during mounting work and securing a large engagement force after mounting. In other words, the bending deformation of the distal end portion of the engagement piece can be secured satisfactorily, so that the cover case can be mounted smoothly, and after installation, the duct wall can be firmly attached to the base end side having a large thickness. Since it can be pressed against the cover case, rattling of the cover case can be suppressed and noise generation can be prevented.

As in the third aspect of the present invention, even when each engaging piece is tapered so that the width dimension gradually decreases as it goes to the protruding end side from the flange, The same effect as item 2 can be obtained.
In other words, the bending deformation of the distal end portion of the engagement piece can be ensured satisfactorily, so that the cover case can be installed smoothly, and after installation, the duct case is installed on the base end side having a large width dimension. Since the tube wall can be firmly pressed, the shakiness of the cover case can be suppressed and the generation of noise can be prevented.

  As in the fourth aspect of the present invention, a latching structure is provided on two opposite sides (for example, vertical sides) of the flange, and two sides (for example, left and right sides) of the flange excluding the portion where the latching structure is formed. If the engagement piece is provided on the side of the direction, the cylindrical wall of the duct case can be clamped not only from the vertical direction but also from the left and right direction, so that the vertical and horizontal shaking is effective. It is excellent in that it can be prevented.

Hereinafter, an embodiment in which a heat exhaust apparatus according to the present invention is applied to a heat exhaust apparatus of an image forming apparatus will be described with reference to the drawings.
1 is an exploded perspective view of the exhaust heat apparatus, FIG. 2 is an overall perspective view of the exhaust heat apparatus, FIG. 3 is a view showing an assembled state of a fan unit constituting the exhaust heat apparatus, and FIG. 4 is a line AA in FIG. FIG. 5 is a cross-sectional view of the heat exhaust device, FIG. 6 is a side cross-sectional view of the temporary fixing means, FIG. 7 is a side cross-sectional view of the main part, and FIG. is there.

As shown in FIGS. 1, 2, and 5, the exhaust heat apparatus 1 includes an air inlet 2 and an air outlet 3, and air is interposed between the air inlet 2 and the air outlet 3. A hollow cylindrical duct case (duct) 5 having a flow path 4, a box-type fan unit 7 that is fitted in the air discharge port 3 of the duct case 5, and an outer surface of the fan unit 7. And a cover case 8 attached to the air discharge port 3 of the duct case 5. As shown in FIG. 2, the heat exhaust apparatus 1 is attached and fixed to the inner frame 9 constituting the image forming apparatus by screws 10. A fixing device is disposed inside the inner frame 9. 1 and 5, reference numeral 11 denotes a screw hole for the screw 10 formed in the duct case 5, and the screw hole 11 and a screw hole (not shown) formed in the inner case 9 are positioned. After matching, the duct case 5 can be attached and fixed to the inner frame 9 by screwing the screws 10.
In the following embodiment, the air outlet 3 side of the duct case 5 is defined as the front, and the air inlet 2 side is defined as the rear. Further, the horizontal direction orthogonal to the front-rear direction is defined as the left-right direction.

  The duct case 5 constitutes the final end of a duct for discharging warm air formed in the image forming apparatus, and the warm air generated in the fixing device of the image forming apparatus is an air inlet at the rear of the duct case 5. 2, and is discharged from the air discharge port 3 to the outside of the image forming apparatus through the cover case 8 through the air flow path 4 by the air blowing action of the fan unit 7.

  In FIG. 1, a duct case 5 is a resin molded product made of ABS resin, and is continuously formed at a rectangular tubular main body 12 and a front end portion of the main body 12 and gradually increases in vertical dimension as it goes forward. A main body portion 12 and a taper portion. 13 is an air flow path 4 in which the rear end opening surface of the main body 12 is the air inlet 2 and the front end opening of the straight tube portion 14 is the air outlet 3.

  As shown in FIG. 5, a partition wall 15 is long in the front-rear direction inside the air flow path 4 from the air inlet 2 of the main body 12 to the air outlet 3 of the tapered portion 13 so as to partition the left-right direction. It is erected. The partition wall 15 divides the air flow path 4 into a main flow path 4a occupying most of the air flow path 4 and a sub flow path 4b having a small left-right width dimension. On the right side surface of the rear end of the main body 12, an extending portion 16 for allowing warm air to flow into the sub-flow channel 4 b is integrally extended in the right direction.

  A mounting portion for mounting and fixing the fan unit 7 is formed on the inner surface of the air discharge port 3 of the duct case 5. As shown in FIG. 1, the mounting portion is a corner piece 19 formed at the four corners of the inner surface of the straight tube portion 14 and having a front mounting surface 18 for receiving the housing 33 of the fan unit 7. A screw hole 20 for stopping is provided. The fan unit 7 is inserted into the straight cylindrical portion 14 in such a posture that the housing 33 of the fan unit 7 is received on the mounting surface 18, and the four corners are fixed to the corner pieces 19 with screws 21, respectively. The unit 7 is attached and fixed to the duct case 5.

  As shown in FIG. 3, the fan unit 7 is a small axial fan. The fan unit 7 is assembled into a housing 33 having an air passage 32 extending from the rear intake surface 30 to the front exhaust surface 31 and the air passage 32. The rotating blade body 34 and the motor 35 that rotates the rotating blade body 34 are included, and warm air sucked from the intake surface 30 is sent out from the exhaust surface 31. That is, the fan unit 7 includes a front side (exhaust surface 31 side: front side) and a back side (intake surface 30 side) depending on the spiral form of the spiral blade piece 36 constituting the rotary blade body 34 and the rotation direction by the motor 35. 3), and as shown in FIG. 3, proper exhaust heat / exhaust operation is executed only when the intake surface 30 is assembled in a normal posture so as to be located on the rear side. It has become.

  As shown in FIGS. 3 and 4, the housing 33 includes a thin regular square outer peripheral frame member 37, a boss member 38 that supports and fixes the motor 35 in the center of the ventilation path 32, and the outer peripheral frame member 37 and the boss member 38. The four stay members 39 are connected to each other, and these are integrally formed. At the four corners of the outer peripheral frame member 37, through holes 37a for the screws 21 are formed in a penetrating manner in the front-rear direction (see FIG. 1).

  The rotary wing body 34 includes a fan boss 40 that also serves as a case on the rotor side of the motor 35, and seven spiral wing pieces 36 that are integrally formed on the outer surface of the fan boss 40. As shown in FIG. 3, each of the spiral blade pieces 36 is spirally continuous with the outer peripheral surface of the fan boss 40 with the intake surface 30 side of the fan unit 7 as the spiral start end portion 42 and the exhaust surface 31 side as the spiral end portion 43. Is formed.

  As shown in FIG. 8, these spiral blade pieces 36 are assembled in a position offset in the housing 33 toward the intake surface 30. Specifically, a distance dimension D1 between the rotation locus of the spiral start end portion 42 of the spiral blade piece 36 and the rear intake surface 30 is determined by the rotation locus of the spiral end portion 43 and the exhaust surface 31 on the front side. It is supposed to be smaller than the front-rear distance dimension D2. That is, the fan unit 7 in the present embodiment is an offset type axial flow fan in which the rotary blade body 34 is biased toward the intake surface.

  The fan unit 7 includes a constraint detection type sensor that can detect the rotation state of the motor 35, and the rotation state of the motor 35 is directed toward the control unit of the image forming apparatus via a lead wire (not shown). Such a detection signal is transmitted. Specifically, when the rotation of the motor 35 is stopped, an ON signal (H signal) is transmitted.

  As shown in FIGS. 1, 2, and 3, the cover case 8 is formed with a regular rectangular main surface portion 50 having a large number of openings, and projecting backward from the outer peripheral edge of the main surface portion 50. This is a resin molded product integrally formed with a square frame-shaped flange 51, and the cylindrical wall (straight cylindrical portion 14) of the air outlet 3 of the duct case 5 so as to cover the outer surface near the exhaust surface 31 of the fan unit 7. The cylinder wall 25) is mounted. A large number of slits 52 that are long in the left-right direction are arranged in the up-down direction in the main surface portion 50, and in the present embodiment, the slits 52 are openings. As shown in FIG. 3, the inner dimension of the rear end edge of the flange 51 is set to be slightly larger than the outer dimension of the front end edge of the straight tube portion 25, and when the cover case 8 is attached to the duct case 5, The rear end edge of the flange 51 is received by the front end edge of the straight tube portion 25.

The cover case 8 is prevented from coming off from the air outlet 3 via a latching structure S (see FIGS. 1, 3, and 4) formed between the cylinder wall 25 of the straight cylinder portion 14 and the flange 51. It is hooked and held in a shape. Such a latching structure S is formed so as to protrude from the rear end edge of the flange 51 toward the rear from the locking claw 53 integrally formed in a projecting manner on the outer surface of the cylindrical wall 25 of the straight cylindrical portion 14, and the locking claw. 53 and a locking piece 54 engaged with 53.
The locking claws 53 are formed at two locations on the upper surface of the cylindrical wall 25 and at one location on the lower surface. Accordingly, a pair of left and right locking pieces 54 and 54 are formed on the upper surface of the flange 51, and a single locking piece 54 is formed at the left and right centers of the lower surface. Each locking piece 54 has a rectangular frame shape, and the cover case 8 is held and fixed to the duct case 5 in a retaining shape by an opening formed at the center thereof engaging the locking claw 53. Is done.

  In addition, engagement pieces 55 and 55 are formed on the left and right side surfaces of the flange 51 to press-contact the left and right outer surfaces of the cylindrical wall 25 of the straight tube portion 14. Each engagement piece 55 has a tapered triangular taper shape in which the width dimension gradually decreases as it goes to the leading end side (rear side) from the flange 51.

  As shown in FIG. 5, each engagement piece 55 is set so that the thickness dimension on the distal end side from the flange 51 is smaller than the thickness dimension on the proximal end side. Here, a rib 56 is formed at the upper and lower central portions of the engagement piece 55 (see FIGS. 1 and 4), and a guide surface 57 that is inclined outward is formed at the front end portion (rear end portion) of the rib 56. Thus, the thickness dimension on the tip side is made small.

  The locking piece 54 and the engaging piece 55 are integrally formed with the main surface portion 50 and the flange 51 when the cover case 8 is molded. That is, the locking piece 54 and the engaging piece 55 are also resin molded products, and can be elastically deformed to a slight extent.

  When the cover case 8 having the above-described configuration is mounted, the elasticity of the locking piece 54 is used to bend and deform the locking piece 54 so as to get over the locking claw 53, so that FIGS. As shown in FIG. 4, the locking piece 54 is engaged with the locking claw 53. Thus, the cover case 8 can be held and fixed to the duct case 5 in a retaining shape. In such a holding and fixing state, the pair of left and right engaging pieces 55 and 55 of the flange 51 clamps the cylindrical wall 25 of the duct case 5 from the left and right outward directions so as to be fixed to the duct case 5. Will be even more solid. Above all, when the duct case 5 is sandwiched between the pair of left and right engaging pieces 55 and 55 in this manner, the cover case 8 can be prevented from rattling, so the motor 35 of the fan unit 7 It is excellent in that the generation of noise caused by the resonance of the cover case 8 due to vibration can be surely prevented.

  When the thickness dimension of the projecting distal end side (rear side) of each engagement piece 55 that comes first to the cylindrical wall 25 of the straight cylindrical portion 14 is set smaller than the thickness dimension of the proximal end side, the bending deformability is ensured. However, a large clamping force can be obtained. That is, since the bending deformability of the distal end portion of the engagement piece 55 can be ensured satisfactorily, the mounting operation of the cover case 8 to the duct case 5 can be smoothly advanced, and after the mounting, on the base end side having a large thickness dimension. Since the cylindrical wall 25 of the duct case 5 can be firmly clamped, rattling of the cover case 8 can be suppressed and noise generation can be prevented.

  Even when each engagement piece 55 is tapered so that the width dimension gradually decreases as it goes to the leading end side of the flange 51, a large clamping force can be obtained while ensuring bending deformation. Obtainable. That is, by reducing the width dimension of the tip portion, it is possible to satisfactorily ensure the bending deformability of the tip portion of the engagement piece 55, so that the mounting operation of the cover case 8 can be proceeded smoothly and the mounting. After that, the cylindrical wall 25 of the duct case 5 can be firmly held on the base end side having a large width dimension, so that the rattling of the cover case 8 can be suppressed and the generation of noise can be prevented.

  If the latching structure S is provided on the upper and lower surfaces of the flange 51 and the engagement pieces 55 and 55 are provided on the left and right surfaces as in the present embodiment, the cylindrical wall 25 of the duct case 5 is moved from all directions in the vertical and horizontal directions. Can be pinched. Therefore, also in this respect, it is possible to suppress the rattling of the cover case 8 and prevent the generation of noise.

  The cover case 8 is provided with a regulating member 59 for preventing the fan unit 7 from being mistakenly attached to the air outlet 3 of the duct case 5 in the forward and reverse directions. The restricting member 59 is a single shaft that is integrally projected rearward from the inner surface of the main surface portion 50 facing the fan unit 7, and is located at the lower left position of the main surface portion 50 when viewed from the front. ing. In the present embodiment, the restricting member 59 is a cross shaft formed so that the outer shape gradually increases from the protruding end toward the protruding proximal end on the main surface portion 50 side.

The rearward projecting dimension of the restricting member 59 is such that it interferes with the rotating blade body 34 only when the fan unit 7 is assembled in the reverse orientation of the front and back.
That is, when the fan unit 7 is assembled in the normal posture with respect to the air discharge port 3, that is, when the fan unit 7 is assembled such that the intake surface 30 side is the rear side as shown in FIG. Even when the cover case 8 is mounted so as to cover the outer surface of the fan unit 7, an opposing gap is secured between the rotation locus of the spiral terminal portion 43 of the spiral blade piece 36 and the regulating member 59, and the rotor blade The body 34 can rotate without hindrance.
However, as shown in FIG. 7, when the fan unit 7 is assembled to the air outlet 3 in the reverse orientation so that the surface facing the cover case 8 is the intake surface 30, the cover is then covered. When the case 8 is mounted, the restricting member 59 interferes with the rotation locus of the spiral start end portion 42 of the spiral blade piece 36 so that the rotating blade body 34 cannot be rotated.
However, the effect is based on the fact that an offset type axial fan (D1 <D2: see FIG. 8) in which the rotating blade body 34 is biased toward the intake surface is employed as the fan unit 7.

When the restriction member 59 is provided in the cover case 8 in this way, the rotor unit 34 can rotate normally after the fan unit 7 and the cover case 8 are mounted on the air outlet 3 of the duct case 5. It is possible to easily confirm whether or not the assembly posture of the fan unit 7 is appropriate simply by checking whether or not the fan unit 7 is assembled. Thereby, the incorrect assembly | attachment of the front-and-back direction of the fan unit 7 in the manufacture process of the heat exhaust apparatus 1 can be prevented reliably.
In addition, since it is possible to reliably prevent the fan unit 7 from being assembled in the reverse posture with a simple configuration in which the restricting member 59 is simply provided in the cover case 8, it is accompanied by providing an erroneous assembly prevention function. It is also excellent in that an increase in manufacturing cost of the heat exhausting apparatus 1 and an increase in manufacturing cost of the image forming apparatus to which the heat exhausting apparatus 1 is applied can be minimized.

  In particular, if the fan unit 7 has a sensor that can detect the rotation state of the motor 35 as in the present embodiment, the fan unit 7 may be erroneously assembled in the manufacturing process of the heat exhausting device 1. Even when the heat exhaust apparatus 1 is assembled in the image forming apparatus as it is, it can be recognized on the image forming apparatus side based on the detection signal from the sensor that the rotating blade body 34 is in a non-rotatable state. . In this way, by controlling the image forming operation of the image forming apparatus to be stopped, the inside of the image forming apparatus can be prevented from becoming abnormally hot, so that the worst situation such as damage to internal parts can be avoided. It becomes possible. This contributes to improving the reliability of the image forming apparatus.

  When the cover case 8 is a resin molded product and the restricting member 59 is a single shaft that is formed so as to protrude from the inner surface of the cover case 8, only the upper and lower molds of the male mold and the female mold are used. The entire cover case 8 including can be molded with resin. Therefore, the design change of the mold is small as compared with the case where the cover case 8 having no shaft body is molded, and an increase in the manufacturing cost of the cover case 8 can be minimized. Thereby, the exhaust heat apparatus 1 can be provided at low cost.

  If the shaft body that is the restricting member 59 is a cross shaft formed so that the outer shape gradually increases as it approaches the projecting base end from the projecting end, the shaft body resists the rotational power of the rotating blade body 34 in a simple form. Since sufficient rigidity can be provided, it is possible to effectively prevent problems such as breakage and deformation of the regulating member 59, and to obtain the heat exhaust apparatus 1 having excellent reliability.

The heat exhaust apparatus 1 having the above-described configuration is an assembly part in which the fan unit 7 and the cover case 8 are assembled in advance to the air discharge port 3 of the duct case 5 and then the inner frame of the image forming apparatus. 9 and fixed by screws 10.
However, when the heat exhaust device 1 is an assembly component in this way, the weight increases by the weight of the fan unit 7 and the like as compared with the case where only the duct case 5 is attached and fixed. A burden becomes large and it is easy to drop the exhaust heat apparatus 1. Further, since the fan unit 7 is mounted at an offset position on one end side (the air exhaust port 3 side) of the duct case 5, the rotational moment when the exhaust heat apparatus 1 is moved increases and the weight balance is increased. It is easy to drop the heat exhausting device 1 by breaking, and this is also disadvantageous.

  Therefore, in the present embodiment, as shown in FIGS. 1, 2, and 6, between the inner frame 9 and the duct case 5, the heat exhausting device 1 is temporarily held on the inner frame 9 prior to screwing and fixing. Temporary fixing means T is provided. Here, the temporary fixing means T includes a protrusion 70 formed in a protruding shape at a predetermined position of the inner frame 9 and a hook that is integrally formed at a predetermined position of the duct case 5 and engages with the protrusion 70. 71.

  Specifically, as shown in FIGS. 1 and 6, the inner frame 9 has a locking wall 72 extending in the horizontal direction on the left and right sides, and a cylindrical protrusion 70 is directed upward at a predetermined position on the upper surface thereof. Projected to

  As shown in FIG. 6, the hook 71 on the duct case 5 side that engages with the inner frame 9 includes an upright wall 73 projecting upward from the upper wall of the main body 12 of the duct case 5, and an upper end of the upright wall 73. A horizontal wall 74 extending in the horizontal direction from the inner frame 9 to the rear side of the inner frame 9 has an L-shaped cross section, and a locking hole 75 that allows the protrusion 70 to be engaged is formed at the center of the surface of the horizontal wall 74. It has been established. Between the upper wall of the duct case 5 (main body portion 12) and the horizontal wall 74 of the hook 71, an opposing gap is formed for clamping the locking wall 72 of the inner frame 9 from the vertical direction.

  As shown in FIG. 6, a corner portion between the rear edge surface and the lower surface of the horizontal wall 74 has a downward guide surface 76 to guide the engagement of the protrusion 70 into the locking hole 75. The guide groove 77 is cut out from the rear end edge surface to the locking hole 75. The guide surface 76 is a front-declining inclined surface. Therefore, the depth dimension of the guide groove 77 is deep at the rear side and shallower toward the front.

  According to the mounting structure of the heat exhaust apparatus 1 including the temporary fixing means T as described above, the heat exhaust apparatus 1 is attached to the inner frame 9 by engaging the protrusion 70 of the inner frame 9 in the locking hole 75 of the hook 71. Can be pre-assembled into a temporarily fixed state. More specifically, the duct case 5 is pushed backward so that the upper wall of the duct case 5 and the horizontal wall 74 of the hook 71 sandwich the locking wall 72 of the inner frame 9 from above and below. The heat exhaust device 1 can be pre-assembled with the inner frame 9 in a temporarily fixed state simply by engaging the projection 70 of the inner frame 9 into the locking hole 70. If the heat exhaust device 1 can be pre-assembled in the temporarily fixed state in this way, the assembly operator can perform the screwing operation with both hands without supporting the heat exhaust device 1. Therefore, it is possible to rationally perform the attaching operation of the heat exhausting apparatus 1 to the image forming apparatus accurately and with less effort and time.

At this time, if the projection 70 of the inner frame 9 is engaged with the locking hole 75 of the hook 71, the hook 71 is inadvertently detached from the inner frame 9, and the heat exhausting device 1 falls off from the inner frame 9. It is possible to proceed safely.
Further, the heat exhaust device 1 can be temporarily fixed at the optimum position by simply pushing the duct case 5 backward after aligning the hook 71 with the protrusion 70. Therefore, the positioning operation of the screw holes of the duct case 5 and the inner frame 9 can be completely abolished, and the screw fixing operation can be efficiently advanced.

  If a guide groove 77 having a downward guide surface 76 is formed in the horizontal wall 74, the projection 70 can be received by the guide groove 77 and guided to the locking hole 75, so that the engaging operation is facilitated. Thus, the temporary fixing work can be efficiently performed. At this time, if the guide surface 76 is an inclined surface with a downward slope, and the depth dimension of the guide groove 77 is deep at the rear side and shallower toward the front, Since the protrusion 70 can be received in the guide groove 77 and guided to the locking hole 75, the locking operation of the protrusion 70 and the locking hole 75 can be lightly advanced with a light force. Further, after temporary fixing, it is possible to reliably restrict the front end edge of the guide groove 77 having a shallow depth dimension from being engaged with the protrusion 70 and being displaced in the forward direction of the duct case 5. Therefore, the heat exhaust apparatus 1 is not inadvertently detached from the temporarily fixed state, and the mounting operation of the heat exhaust apparatus 1 can be proceeded safely and reliably.

It is a disassembled perspective view of the heat exhaust apparatus which concerns on this invention. It is the whole heat exhaust apparatus perspective view. It is a figure which shows the assembly | attachment state of the fan unit which comprises a heat exhaust apparatus. FIG. 4 is a sectional view taken along line AA in FIG. 3. It is a cross-sectional view of a heat exhaust apparatus. It is a sectional side view of a temporary fix | stop means. It is a sectional side view of the principal part. It is a figure for demonstrating the offset structure of a fan unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat exhaust device 2 Air inflow port 3 Air exhaust port 4 Air flow path 5 Duct (duct case)
7 Fan unit 8 Cover case 25 Cylinder wall 50 Main surface 51 Flange 52 Opening (slit)
55 Engagement piece S Hanging structure

Claims (4)

A duct having an air inlet and an air outlet, and having an air flow path between the air inlet and the air outlet;
A box-type fan unit that is fitted in a cylindrical wall that forms the air discharge port of the duct, and whose rotor blades are biased toward the intake surface ;
A heat exhaust device including a cover case attached to the cylindrical wall of the air discharge port so as to cover the outer surface of the fan unit,
The cover case includes a main surface portion having a large number of openings and covering the air discharge port, and a flange formed to project from the outer peripheral edge of the main surface portion toward the air discharge port,
The cover case is latched and held in a retaining manner with respect to the air discharge port of the duct by engaging a locking claw formed on the cylindrical wall and a locking piece formed on the flange. ,
Engagement pieces for press-contacting the outer surface of the cylindrical wall are formed in at least two places of the flange, and these engagement pieces are formed to project from the outer peripheral edge of the flange toward the air discharge port ,
The cover case is provided with a restricting member that protrudes from the main surface portion toward the fan unit and interferes with the rotor blades only when the fan unit is assembled in the reverse orientation of the front and back sides. An exhaust heat device characterized by.   The heat exhaust apparatus according to claim 1, wherein a thickness dimension of a projecting distal end side from the flange of each engagement piece is set smaller than a thickness dimension of a proximal end side.   3. The heat exhausting device according to claim 1, wherein each engagement piece has a tapered shape in which the width dimension gradually decreases as it goes to a protruding tip side from the flange. The cylindrical wall that defines the air discharge port has a square cylindrical shape, and the flange of the cover case that is externally fitted to the cylindrical wall has a rectangular frame shape,
On the two opposing sides of the four peripheral parts of the cylindrical wall and the flange, the latching structure is provided,
The engagement pieces are provided on two sides of the flange excluding the place where the latch structure is formed,
The heat exhaust apparatus according to any one of claims 1 to 3, wherein the flange is fitted and fixed to the cylindrical wall in a state where the outer surface of the cylindrical wall on the duct case side is sandwiched by these engagement pieces.

Images