JP6661351B2 - Air filter assembly and image forming apparatus - Google Patents

Description

  The present invention relates to an air filter assembly such as a dust filter provided in an exhaust duct of an image forming apparatus.

  The image forming apparatus includes a plurality of electric components such as a plurality of motors, a blower fan, a power supply board, and the like as driving sources of various components from conveyance of a recording material to image formation and discharge of a product.

  However, electric components such as a motor and an electric board generate heat, and the heat is accumulated in the image forming apparatus and the temperature rises. As a result, a member such as a plastic conveyance guide installed in the image forming apparatus is thermally deformed, which causes a conveyance jam of the recording material.

  Further, depending on the environment of the installation place of the image forming apparatus, the dust may accumulate in the image forming apparatus, or the dust may be lifted and floated by vibration due to the operation of the image forming apparatus or airflow of a blower fan. As a result, dust adheres to the surface of the recording material, and when the image is transferred to the recording material, a part of the image is chipped, which causes a deterioration in image quality due to an image defect.

  Therefore, a blower fan and a duct for purifying and exhausting air in the image forming apparatus are provided, and a filter for collecting dust is provided in a path of the duct.

  Further, in the image forming apparatus, in addition to dust, chemical substances may be generated from various inorganic materials such as resins and metals used for various components constituting the image forming apparatus. In addition, odor molecules emitted by various organic materials used for surface treatment materials and the like, and unpleasant chemical molecules such as volatile organic compounds (VOCs) generated by heating these materials may be generated. is there. An air filter for trapping or decomposing these chemical molecules may be provided in the path of the duct.

  In Patent Literature 1, a filter is installed on a base frame having an installation portion for installing a pleated filter. Then, the cover frame formed integrally with the base frame and the hinge is rotated with the hinge as a rotation starting point, and the filter is held between the base frame and the base frame. Then, the projection for fitting provided on the cover frame is fitted to the cantilever support member having the fitting hole provided on the base frame and closed. This constitutes a filter assembly.

  As a result, the dust filter can be captured and the dirty filter can be removed. That is, since the filter can be replaced with a new one, the replacement work at the time of maintenance can be simplified, and a great merit can be obtained.

  In Patent Literature 2, a flat filter is installed on a first frame. Then, the second frame for holding the filter formed integrally with the first frame and the hinge is folded into two on the first frame by bending the hinge.

  Then, a locking claw provided on the first frame locks the frame (thin plate) of the second frame. Further, a bent piece having an engagement hole formed integrally with the first frame by a hinge is formed on the engagement projection provided on the second frame, and the hinge is turned back to form the engagement hole of the bent piece into the engagement projection. Is engaged.

  This constitutes a filter assembly. When the filter becomes dirty, the entire filter assembly in which the frame and the filter are integrally formed has been replaced. However, only the dirty filter can be replaced with a new filter. As a result, the running cost can be reduced.

JP-T-2007-516829 JP-A-11-63597

  However, with the filter structure of Patent Document 1, the following is the procedure for attaching and detaching and replacing a dirty filter. First, the frame frame body is released by releasing the cantilever support members having the fitting holes provided in the base frame of the filter case one by one from the fitting protrusions provided in the cover frame. open.

  Next, the dirty filter is taken out of the filter case. Next, a new filter is sandwiched between the bellows-shaped pleated woven non-woven fabric filter and the guide provided with the uneven valleys provided on the frame frame.

  At that time, in the case of a filter that has been subjected to processing such as melt flow, there is elasticity even if pleated weaving, so it is unstable until the filter frame is closed to fit the uneven part well, so it takes time and effort to work take time.

  As another method for solving such a problem, a flat nonwoven fabric filter that is not pleated is used. As one example, a configuration using a frame as in Patent Document 2 is known.

  In the filter structure of Patent Literature 2, first, a new filter is placed on the opened filter case. Next, an operation of fitting the filter frame with the fitting claw and the frame is performed. Next, the filter frame is assembled by folding the bent piece having an engagement hole and folding the hinge to engage the engagement hole with the engagement protrusion provided on the frame.

  However, during maintenance of the device, the dirty filter is removed. This takes time and effort to perform the work of engaging or disengaging a plurality of engaging portions one by one, such as following the above work in reverse.

  The filter of Patent Literature 1 is not pushed out to the grid-like lateral rib side, but if pushed to the opposite side, it is held only by the width of the edge, so it slips off from the edge and falls off There is.

  Further, since the grid-shaped ribs are provided on the entire surface of one side, the opening area is reduced by the size of the grid-shaped ribs, so that the pressure loss of the wind passing through the filter increases, and the efficiency is reduced.

  Further, the filter may be pushed in a direction perpendicular to the surface toward the opening side. Also, when the wind pressure of the blower fan is applied, the filter slips off from the case frame which is the filter frame, and the filter comes off and falls off. This may cause failure such as spread of dirt due to the re-scattering of the collected dust and the entanglement of the filter in the blower fan.

  Further, in the case of Patent Literature 1, the state of the fiber density and the thickness of the layer differs depending on the filter material, shape, manufacturing method, and the like. .

  Further, when the holding area is increased in the width direction, there is a possibility that the opening area is reduced and the dust collecting performance is reduced.

  On the other hand, in order to hold a non-woven fabric filter used for these, there is a case where a projection provided on a frame body is made to penetrate and hold the filter.

  In particular, in the case of a filter that has been subjected to processing such as spunbonding or melt flow, which is a processing for preventing the fiber from being frayed, it is difficult to move because the fibers are bonded to each other. The spun-bounded fabric is a kind of non-woven fabric, which is made directly into a sheet before the fibers are hardened sufficiently when spinning chemical fibers.

  For this reason, a hole may not be easily formed in the filter material. Even if the filter is forcibly pinched by the frame, there is a problem that the filter slips through the gap and the filter cannot be held.

  If the hole is forcibly widened, there is a problem that the fiber is damaged, and the flat surface portion of the filter is deformed in a dish shape due to the stress of the hole portion. Therefore, increasing the number of processing steps by forming a shape such as providing a through hole in advance may lengthen the manufacturing process, and may increase the possibility of an operation error.

  An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide an air filter assembly in which a filter frame securely holds a filter and improves workability such as installation and replacement of the filter. It is.

  A typical configuration of the air filter assembly according to the present invention for achieving the object is a filter, and a filter frame holding the filter, an air filter assembly, wherein the filter frame is attached to the filter A first frame portion having a first opening to vent, and having a second opening to vent the filter, a second frame portion configured to be openable and closable with respect to the first frame portion, The first frame portion has a projection row in which a plurality of needle claw-shaped projections are arranged in a row at intervals on at least a part of a peripheral portion of the first opening, The second frame portion includes an inner peripheral projection row in which a plurality of needle claw-shaped projections are arranged in a row at intervals on at least a part of a peripheral edge of the second opening, and an outer peripheral section of the inner peripheral projection row. Needle-shaped protrusions at least in part An outer peripheral projection row arranged side by side in a row at intervals, and the first frame portion, when the second frame portion is closed, the inner peripheral projection row, The filter is held by interposing and engaging the projection row from both sides with the outer circumference projection row.

  ADVANTAGE OF THE INVENTION According to this invention, a filter frame can hold | maintain a filter reliably and can improve the workability | operativity of filter installation and replacement.

FIG. 1 is an explanatory cross-sectional view illustrating a configuration of an image forming apparatus including an air filter assembly according to the present invention. FIG. 2 is a perspective explanatory view showing a state where the air filter including the air filter assembly according to the first embodiment is mounted on an exhaust duct of the image forming apparatus. A rectangular annular sponge serving as a gap filling member is adhered to the outer peripheral portion of an edge wall provided on a first frame portion of the air filter assembly of the first embodiment with a double-sided tape, and the air filter assembly is attached to the air filter. It is a perspective explanatory view completed as. FIG. 2A is a front view illustrating a configuration of a filter frame included in the air filter assembly according to the first embodiment. FIG. 2B is a top view illustrating a configuration of a filter frame included in the air filter assembly according to the first embodiment. FIG. 2C is a left side view illustrating a configuration of a filter frame included in the air filter assembly according to the first embodiment. (D) is an AA sectional view of (a). It is a perspective explanatory view showing the composition of the filter frame which constitutes the air filter assembly of a 1st embodiment. FIG. 6 is a partially enlarged view showing a configuration of a needle claw-shaped projection by enlarging a corner B shown in FIG. 5. FIG. 4 is a perspective explanatory view showing a state in which a filter frame constituting an air filter assembly of the first embodiment is closed by rotating and closing a first frame portion and a second frame portion around a hinge portion. is there. The filter frame constituting the air filter assembly of the first embodiment bends a thin-walled flexible portion constituting a hinge portion so that the first frame portion and the second frame portion are connected to the flexible portion. FIG. 3 is an explanatory cross-sectional view showing a state in which it is configured to be rotatable around the center. FIG. 3 is an explanatory cross-sectional view showing a state in which a filter is sandwiched between a first frame portion and a second frame portion in a state where a filter frame constituting the air filter assembly of the first embodiment is closed. Plane | planar explanatory drawing which shows the arrangement structure of each needle claw-shaped protrusion formed in the 1st frame part side and the 2nd frame part side in the state which closed the filter frame which comprises the air filter assembly of 1st Embodiment, respectively. It is. It is a perspective explanatory view showing the composition of the filter frame which constitutes the air filter assembly of a 2nd embodiment. It is sectional drawing which shows the state which the filter was clamped between the 1st frame part and the 2nd frame part in the state which closed the filter frame which comprises the air filter assembly of 2nd Embodiment.

  An embodiment of an air filter assembly according to the present invention and an image forming apparatus having the same will be specifically described with reference to the drawings.

  First, a configuration of a first embodiment of an air filter assembly and an image forming apparatus including the same according to the present invention will be described with reference to FIGS.

<Image forming apparatus>
FIG. 1 is an explanatory cross-sectional view showing a configuration of an image forming apparatus provided with an air filter assembly according to the present invention. The image forming apparatus 30 shown in FIG. 1 includes four photosensitive drums 10a to 10d serving as image carriers for forming toner images of yellow, magenta, cyan, and black. For convenience of explanation, the photosensitive drums 10a to 10d may be simply described using the photosensitive drum 10 as a representative. The same applies to other image forming process means.

  Around the respective photosensitive drums 10, a charging device (not shown) serving as a charging unit, a developing device serving as a developing unit, and a cleaner serving as a cleaning unit are arranged. These image forming process means are integrally unitized as process cartridges 1a to 1d.

  An intermediate transfer belt 12 that is an image carrier that is in contact with the surface of each photosensitive drum 10 is provided on an upper portion of each process cartridge 1. The intermediate transfer belt 12 is rotatably stretched by stretching rollers 11a to 11c.

  The surface of each photosensitive drum 10 is uniformly charged by a charging device (not shown). The uniformly charged surface of each photosensitive drum 10 is irradiated with laser light 6A corresponding to image information of each color of yellow, magenta, cyan, and black separated by a laser scanner 6 serving as an image exposure means. Exposure produces an electrostatic latent image.

  On the surface of each photosensitive drum 10, an electrostatic latent image is formed according to image information of each color of yellow, magenta, cyan, and black. Each electrostatic latent image formed on the surface of each photosensitive drum 10 is supplied with a developer by a developing device (not shown) and developed as a toner image. As a result, a toner image of each color of yellow, magenta, cyan, and black is formed on the surface of each photosensitive drum 10.

  With the rotation of each photosensitive drum 10 in the clockwise direction in FIG. 1, the toner image formed on the surface of each photosensitive drum 10 comes into contact with the surface of each photosensitive drum 10 and the outer peripheral surface of the intermediate transfer belt 12. It reaches the primary transfer section.

  On the other hand, the intermediate transfer belt 12 rotates counterclockwise in FIG. On the inner peripheral surface side of the intermediate transfer belt 12, primary transfer rollers 2a to 2d serving as primary transfer means provided to face the respective photosensitive drums 10 are provided. A primary transfer bias voltage is applied to each primary transfer roller 2 from a primary transfer bias power supply (not shown).

  The toner image formed on the surface of each photosensitive drum 10 is sequentially formed on the outer peripheral surface of the intermediate transfer belt 12 moving in the counterclockwise direction in FIG. 1 by the primary transfer bias voltage applied to each primary transfer roller 2. Transcribed.

  On the other hand, the recording material P stored in the feeding cassette 4 is fed out by a pickup roller 8 and fed out one by one in cooperation with a separating unit (not shown). The leading end of the recording material P is abutted against the nip portion of the registration roller 9 once stopped, and the skew is corrected by the stiffness of the recording material P.

  The recording material P is conveyed to a secondary transfer portion formed by a nip between the secondary transfer roller 3 serving as a secondary transfer unit and the outer peripheral surface of the intermediate transfer belt 12 while being nipped by the registration roller 9. The registration roller 9 conveys the recording material P in synchronization with the position of the toner image primarily transferred on the outer peripheral surface of the intermediate transfer belt 12.

  A secondary transfer bias voltage is applied to the secondary transfer roller 3 from a secondary transfer bias power supply (not shown), and the toner image which is primarily transferred and superimposed on the outer peripheral surface of the intermediate transfer belt 12 is collectively printed on the recording material P. Is secondarily transcribed.

  The recording material P on which the toner image has been secondarily transferred is conveyed to a fixing device 5 serving as a fixing unit, and heated and pressed in a process of being nipped and conveyed by a fixing roller and a pressure roller provided in the fixing device 5. Then, the toner of each color is heat-melted and mixed, and is thermally fixed to the recording material P.

  The recording material P on which the full-color toner image (image) is fixed is nipped and conveyed by discharge rollers 21 provided downstream of the fixing device 5 and discharged onto the discharge tray 7.

  The image forming apparatus 30 of the present embodiment is provided with a feed cassette 4, a laser scanner 6, a process cartridge 1, an intermediate transfer belt 12, and a discharge tray 7 in this order from below to above in FIG.

  Such an image forming apparatus 30 has been multifunctional and the number of various components has been increased, so that the image forming apparatus 30 has been increased in size and processing speed. Electric components serving as heat sources increase in the image forming apparatus 30 main body, and the temperature in the image forming apparatus 30 main body increases. Therefore, a high exhaust efficiency is required for the exhaust duct and the like in order to prevent the temperature inside the image forming apparatus 30 from rising.

  In addition, the vibration of the main body of the image forming apparatus 30 increases due to the increase in the printing speed of the image forming apparatus 30. For this reason, in addition to dirt caused by the image forming process, such as toner powder flowing in the main body of the image forming apparatus 30, dust such as the use environment also increases in proportion to the cooling air flow. For this reason, the dust collection filter, which is a dust collection component in the exhaust duct, requires high dust collection efficiency.

  Further, the size of the image forming apparatus 30 is increased and the processing speed is increased by increasing the number of functions. In order to maintain the quality of the image forming apparatus 30, it is necessary to ensure high exhaust efficiency and dust collection efficiency of the exhaust duct. For this reason, periodic maintenance of the dust collecting filter as a dust collecting component is required.

  For this reason, periodic replacement of the dust collection filter or cleaning is indispensable. Since the frequency of replacement of a dust collection filter that has become dirty due to dust collection increases, it is required to improve the workability of installation and replacement of the dust collection filter.

  There is a form of working in a user's work area such as a desktop type printer or an MFP (Multifunction Printer), or in a small office such as a home using a personal computer or the Internet. In the image forming apparatus 30 installed in a narrow place such as an SOHO (small office home office), the cleaning of the dust collecting filter in consideration of not only the exhaust heat discharged outside the apparatus, but also the toner powder, odor and the like. The demand for conversion is increasing.

  In order to meet these requirements, in the present embodiment, the ease of installation of the dust collection filter and the ease of maintenance such as replacement work are improved, and the maintenance time is reduced. Further, the present invention provides an air filter assembly 31 of the image forming apparatus 30 that minimizes downtime during which the system or service is stopped and reduces running costs.

<Air filter assembly>
FIG. 2 is an explanatory perspective view showing a state in which the air filter assembly 31 of the present embodiment is installed in the image forming apparatus 30. FIG. 3 is a perspective explanatory view showing the configuration of the air filter assembly 31 of the present embodiment.

  FIGS. 4A to 4C are a front view, a top view, and a left side view, respectively, showing the configuration of the filter frame 40 constituting the air filter assembly 31 of the present embodiment. FIG. 4D is a cross-sectional view taken along the line AA of FIG.

  FIG. 5 is a perspective explanatory view showing a configuration of a filter frame 40 constituting the air filter assembly 31 of the present embodiment. FIG. 6 is a partially enlarged view showing the configuration of the needle claw-shaped projection 40f by enlarging the corner B shown in FIG.

  FIG. 7 shows a filter frame constituting the air filter assembly 31 by rotating and closing the first frame portion 40a and the second frame portion 40b around the hinge portion 40j shown in FIGS. It is a perspective explanatory view showing the state where 40 was closed.

  FIG. 8 shows that the second frame portion 40b is bent around the flexible portion 40v by bending the thinly formed flexible portion 40v constituting the hinge portion 40j shown in FIGS. It is sectional explanatory drawing which shows a mode that it was comprised so that rotation is possible in D1, D2 direction.

  FIG. 9 is a sectional explanatory view showing a state where the filter 32 is sandwiched between the first frame portion 40a and the second frame portion 40b in a state where the filter frame 40 constituting the air filter assembly 31 is closed. It is.

  In the filter frame 40 holding the filter 32, the filter 32 is sandwiched and held between the first frame portion 40a and the second frame portion 40b during assembly.

  FIG. 10 is a view showing the needle claw-shaped projections 40f formed on the first frame portion 40a side and the second frame portion 40b side in a state where the first frame portion 40a and the second frame portion 40b are closed. It is a plane explanatory view showing an arrangement composition.

  As shown in FIG. 3, the air filter assembly 31 of the present embodiment has a filter frame 40 that sandwiches and supports four sides of a rectangular filter 32.

  As shown in FIGS. 4 and 5, the filter frame 40 includes a first frame portion 40 a having a rectangular frame shape corresponding to the outer shape of the filter 32 and a second frame portion 40 b.

  As the material of the filter frame 40, it is preferable to use a resin material such as polypropylene or nylon having relatively excellent toughness and repeated fatigue characteristics.

  The first frame portion 40a has an opening 40g (first opening) for ventilating the filter 32. The second frame portion 40b has an opening 40d (a second opening) for ventilating the filter 32.

  As shown in FIG. 8, the first frame portion 40a and the second frame portion 40b rotate in directions of arrows D1 and D2 around a hinge portion 40j including a flexible portion 40v having flexibility. And can be opened and closed mutually.

  As shown in FIGS. 4, 5 and 8, the first frame portion 40a and the second frame portion 40b are mutually connected via two hinge portions 40j each having a thin flexible portion 40v. Be linked. Openings 40g and 40d each having a rectangular through hole for securing ventilation to the filter 32 are formed in both the first frame portion 40a and the second frame portion 40b which are integrally formed.

  40 w shown in FIGS. 4, 5 and 6 is a peripheral portion of the opening 40 d provided in the second frame portion 40 b, and 40 m is a peripheral portion of the opening 40 g provided in the first frame portion 40 a. is there.

  As shown in FIGS. 4, 5, and 6, a plurality of needle claw-shaped projections 40f are arranged at predetermined intervals on the entire periphery of the peripheral portion 40m of the opening 40g provided in the first frame portion 40a. Protrusion rows 40n arranged in a row are integrally provided on the first frame portion 40a.

  Further, an inner peripheral projection row 40x in which a plurality of needle claw-shaped projections 40f are arranged in a row at predetermined intervals around the entire periphery 40w of the opening 40d provided in the second frame section 40b. Are provided integrally with the second frame portion 40b.

  As shown in FIG. 9, a plurality of needle claw-shaped protrusions 40f are provided at predetermined intervals on the outer periphery of the inner peripheral protrusion row 40x over the entire periphery of the peripheral edge portion 40w of the opening 40d with the valley portion 40k interposed therebetween. An outer peripheral projection row 40y arranged in a row is integrally provided on the second frame portion 40b.

<Needle claw projection>
As shown in FIG. 6, the needle-like tip portion 40u, which is the top of the needle claw-like projection 40f, is substantially directed outwardly of each of the first and second frame portions 40a and 40b formed of the frame. It has a vertical surface 40s. Further, each of the first and second frame portions 40a and 40b formed of a frame has an inclined surface 40t that is gently inclined inward of each of the first and second frame portions 40a and 40b. Furthermore, it has a pair of side surfaces 40z that connect the substantially vertical surface 40s and the inclined surface 40t. Thus, the needle-shaped tip portion 40u is formed in a sharp shape that bites into the fibrous portion of the filter 32.

  As shown in FIG. 8, the flexible portion 40v of the hinge portion 40j is bent to close the first frame portion 40a and the second frame portion 40b. At this time, as shown in FIG. 9, the needle claw-shaped protrusion 40f provided on the first frame portion 40a is formed in a valley between the needle claw-shaped protrusions 40f provided on the second frame portion 40b shown in FIG. Engage facing 40p.

  Further, the needle claw-shaped protrusion 40f provided on the second frame portion 40b is engaged with and meshes with the valley portion 40p between the needle claw-shaped protrusions 40f provided on the first frame portion 40a.

  As shown in FIGS. 4A and 9, a plurality of needle claw-shaped protrusions 40 f provided in a row over the entire periphery of the peripheral portion 40 w of the opening 40 d provided in the second frame portion 40 b are formed. An inner peripheral projection row 40x is formed. A valley part 40k is formed between the outer peripheral projection row 40y provided on the outer side thereof. The valley portion 40k faces a projection row 40n including a plurality of needle claw-shaped projections 40f provided in a row over the entire periphery of a peripheral edge portion 40m of the opening 40g provided in the first frame portion 40a. And engage.

  As shown in FIG. 10, each of the claw-shaped protrusions 40f formed on the first frame portion 40a and each of the claw-shaped protrusions 40f formed on the second frame portion 40b are also vertically aligned. They are also arranged in the lateral direction with their positions shifted from each other.

  As shown in FIG. 8, the filter 32 is accommodated in the frame body of the first frame portion 40a and the second frame portion 40b, and the flexible portion 40v is bent around the hinge portion 40j to form the first frame. The part 40a and the second frame part 40b are rotated and closed.

  The filter 32 of the present embodiment is formed of a flat fibrous nonwoven fabric. As shown in FIG. 9, each of the claw-shaped protrusions 40f provided on the first frame portion 40a side from both sides of the peripheral portion of the filter 32, and each of the claw-shaped protrusions provided on the second frame portion 40b side. The projections 40f bite into the fibrous component of the filter 32, and the peripheral edge of the filter 32 is held.

  In the peripheral portion of the filter 32, a projection row 40n formed by a plurality of needle claw-shaped projections 40f provided on the first frame portion 40a side is as follows. It engages with the valley portion 40k between the inner peripheral projection row 40x formed by the plurality of needle claw-shaped projections 40f provided on the second frame section 40b side and the outer peripheral projection row 40y provided outside thereof. As a result, the filter 32 is held in a state of being convexly curved toward the valley portion 40k.

  At this time, the inner projections 40x and the outer projections 40y provided on the second frame portion 40b side from the upper portion of the filter 32 shown in FIG. 9 form needle-like claws provided on the first frame portion 40a side. Pressing is performed so as to sandwich the projection row 40n formed by the projections 40f.

  As shown in FIG. 9, the first frame part 40a and the second frame part 40b are closed. At this time, the inner row 40x and the outer row 40y provided on the side of the second frame 40b engage with the row of projections 40n provided on the side of the first frame 40a from both sides. Thus, the filter 32 is held.

  Thus, the filter 32 does not shift in the direction orthogonal to the pressing direction indicated by the arrow E in FIG. 9 (up, down, left and right directions in FIG. 10). The needle-like tip portions 40u of the needle claw-like projections 40f constituting the projection row 40n provided on the first frame portion 40a side penetrate deeply into the fibrous portion of the filter 32. Thereby, the filter 32 can be held efficiently.

  The filter 32 is reliably held by the projection row 40n provided on the first frame section 40a side. Accordingly, the inner peripheral projection row 40x and the outer peripheral projection row 40y provided on the side of the second frame portion 40b arranged on both sides of the projection row 40n can also surely enter the fibrous portion of the filter 32.

  The needle-like tip portions 40u of all the needle claw-like projections 40f provided on each of the first and second frame portions 40a and 40b bite into the fibrous portion of the filter 32. Then, the peripheral edges of the four sides of the filter 32 are held in a substantially “H” -shaped state as shown in FIG. 9 by the pressing force indicated by the arrow E direction shown in FIG.

  As shown in FIG. 9, the first and second frame portions 40 a and 40 b are located closer to the pressing force C received by the filter 32 by the inner circumferential projection row 40 x provided on the second frame portion 40 b side. There is no needle claw-shaped protrusion 40f on the side of the openings 40g, 40d.

  Therefore, the filter 32 does not receive the pressing force opposing the pressing force C received by the inner peripheral projection row 40x provided on the second frame portion 40b side from any of the needle claw-shaped projections 40f.

  For this reason, as shown in FIG. 9, the central portion of the filter 32 has a shape depressed by the height H1 from the surface of the valley portion 40p between the plurality of needle claw-shaped protrusions 40f provided on the second frame portion 40b. Become.

  Then, all the needle claw-like projections 40f provided on each of the first and second frame portions 40a and 40b shown in FIG. 8 so as to fall within the range of the thickness H of the air filter assembly 31 shown in FIG. Height L is set.

  As shown in FIG. 8, the second frame portion 40b is provided so as to be able to rotate in the directions of arrows D1 and D2 in FIG. 8 by bending the flexible portion 40v about the hinge portion 40j.

  With the filter 32 disposed between the first frame part 40a and the second frame part 40b, the first frame part 40a and the second frame part 40b are rotated to Insert the surface.

  Then, the filter 32 is accommodated inside the outer peripheral frame 40r erected perpendicularly to the filter installation surface 40c1 at the peripheral edge of the first frame portion 40a. And it is pinched while being pressed so as to undulate in a gap between each needle claw-shaped projection 40f of each of the first and second frame portions 40a, 40b and the valley portion 40p therebetween.

  As shown in FIG. 7, in the outer peripheral frame 40r provided on the peripheral portion of the first frame portion 40a, three sides other than the one side provided with the hinge portion 40j are provided on the top end of the outer peripheral frame 40r, respectively. A locking claw 40h (locking portion) is provided.

  At a position corresponding to the locking claw 40h on the peripheral edge of the second frame portion 40b, a fitting portion 40i serving as a locked portion with which the locking claw 40h is engaged is provided.

  Then, as shown in FIG. 8, the second frame portion 40b bends the flexible portion 40v about the hinge portion 40j and rotates in the direction of arrow D2 in FIG. 8, thereby sandwiching the filter 32 inside from both sides. Close in the state. Then, the locking claw 40h of the first frame portion 40a is locked and held and fixed to the fitting portion 40i of the second frame portion 40b by snap fitting.

  As shown in FIG. 3, a gap filling member 40e made of a soft material such as a rectangular annular sponge is attached to the outer peripheral portion of the outer peripheral frame 40r provided on the first frame portion 40a shown in FIG. Attached. Thus, the air filter assembly 31 is completed as the air filter 13.

<Filter>
The filter 32 of the present embodiment is a nonwoven fabric filter. Since the nonwoven fabric is formed into a sheet shape by accumulating fibers, the nonwoven fabric is weakly deformed due to external strength.

  When a nonwoven fabric is used as the air filter 13, facilitating the passage of air through the nonwoven fabric greatly affects the exhaust efficiency.

  On the other hand, an appropriate constant density is required so that dust, which is an object to be collected, is held in the gaps between the fibers of the nonwoven fabric. If the density is not stable, it causes unstable factors such as the air volume of the exhaust fan, the pressure loss of the filter 32, the collection efficiency, the life of the filter 32, and the like, so that the entire image forming apparatus 30 provided with the air filter 13 is greatly affected.

  The filter 32 of the present embodiment has been subjected to a special treatment for the purpose of maintaining the shape and preventing the fibers from fraying. The filter 32 of the present embodiment includes first and second filters as fixing means for preventing the fibers constituting the nonwoven fabric from microscopically shifting from each other at a point where the fibers contact each other and changing the positions of the fibers. A needle claw-shaped projection 40f is provided on each of the frame portions 40a and 40b.

  As a nonwoven fabric processing method, for example, there is a thermal bonding method in which contact portions of fibers are mutually welded by blowing heated air. There is also a chemical bond method in which fibers are mutually bonded by spraying an adhesive with a spray or the like. In addition, there is a needle punch method in which the needle is moved at a high speed to entangle the fibers. In addition, there is a stitch bonding method in which the filament is sewn with a filament that is a long single fiber. In addition, various processing methods such as a hydroentanglement method in which fibers are entangled by water pressure are known.

  According to these processing methods, it is possible to minimize the displacement between the fibers.

  Also in the present embodiment, the filter 32 is used in which the fiber density is stabilized by minimizing the displacement between the fibers by the processing method described above.

  Although the filter 32 of the present embodiment will be described as an example of a dust collection filter, the filtering function of the filter 32 is not limited to dust collection.

  For example, there is a nonwoven fabric having an adsorbent such as activated carbon and collecting molecules of specific chemical substances such as odor molecules and volatile organic compounds (VOC). Some have a function of decomposing molecules of a chemical substance by a photocatalyst or the like.

  Even if a needle such as an insect pin having a diameter of about 0.5 mm is pierced into the filter 32 having a certain fiber density and having a stable fiber structure, it does not easily penetrate.

  This is because the needle is difficult to penetrate because the gap between the fibers is small and the fibers are fixed and no positional displacement occurs.

  In the present embodiment, as shown in FIGS. 7 and 9, the filter 32 is sandwiched and held between the first frame portion 40a and the second frame portion 40b.

  As shown in Patent Document 2, if the filter material is simply sandwiched between flat surfaces, the material easily passes through and falls off. In the present embodiment, a plurality of needle claw-shaped projections 40f are provided in a row on each of the first and second frame portions 40a and 40b in order to prevent the filter 32 from falling off.

  Further, as shown in FIG. 9, among the plurality of needle claw-shaped projections 40f provided on each of the first and second frame portions 40a and 40b, a plurality of needle claw-shaped protrusions provided on the first frame portion 40a. The projection rows 40n formed by the projections 40f were arranged as follows. The plurality of needle claw-shaped protrusions 40f provided on the second frame portion 40b are arranged so as to be sandwiched from both sides by an inner circumferential protrusion row 40x formed by the plurality of needle claw-like protrusions 40f and an outer circumferential protrusion row 40y provided outside thereof.

  FIG. 2 is a perspective explanatory view showing a state in which the air filter 13 shown in FIG. 3 is attached to the exhaust duct 61 of the image forming apparatus 30.

  As shown in FIG. 2, the air filter assembly 31 receives the air pressure of a blower fan for intake and exhaust when the image forming apparatus 30 is in use.

  For example, when a square axial flow fan having a size of about 80 mm to 100 mm on one side is used, the drop-off strength, which is generally the force that the air filter assembly 31 must hold against wind pressure, is 1.96 N ( About 200 gf).

  For this reason, in the configuration disclosed in Patent Document 2 in which the filter material is simply sandwiched between the surfaces of the frame, the filter material easily falls off the frame.

  In order to verify the effect of the present embodiment, a normal force is applied to the filter surface by a tension gauge in a state where the filter 32 is mounted on the frame disclosed in Patent Document 2. Then, the load when the filter 32 is gradually displaced from the frame and the filter 32 falls off the frame to form an opening is measured by a tension gauge. Then, it was 490 mN (50 gf) or less, and it was found that the filter 32 easily dropped from the frame.

  In order to prevent the filter 32 from falling off, the present inventors use various shapes such as conical, cylindrical, pyramid, and quadrangular pyramid-shaped projections and ribs to form the filter 32. We have been studying how to prevent slippage.

  However, it was difficult to clear 1.96 N (200 gf), which is the standard for the falling strength of the filter 32 due to the wind pressure of the blower fan.

  For example, the projection is configured to penetrate the filter 32. Thereby, 1.96 N (200 gf), which is the drop strength standard of the filter 32 due to the wind pressure of the blower fan, can be cleared. However, the filter 32 made of a non-woven fabric is subjected to a fiber processing that is difficult to pass through a needle as described above. For this reason, it is not easy to make the projection penetrate the filter 32.

  As a result of study by the present inventors, as in the present embodiment, the needle-like tip portions 40u of the plurality of needle claw-like projections 40f provided on each of the first and second frame portions 40a and 40b are used for the filter 32. It was configured to pierce and hold.

  As a result, the falling strength of the filter 32 held by the air filter assembly 31 of the present embodiment does not fall even when a load of 4.9 N (500 gf) is applied. For this reason, 1.96 N (200 gf), which is the standard for the falling strength of the filter 32 due to the wind pressure of the blower fan, could be cleared.

  In addition, the thickness of the filter 32 formed of a rectangular flat plate differs from 2 mm to 5 mm depending on the application. The holding conditions were taken into consideration in the case of the filter 32 having a thickness of 2 mm, which is the most difficult to secure the falling strength.

  As a result, the depth of the needle-claw-shaped protrusion 40f sunk into the filter 32 was about 1 mm, and the minimum number of fibers that could be hooked on the needle-claw-shaped protrusion 40f in this case was 80. The tensile breaking strength when the filter 32 was hooked on one needle claw-shaped projection 40f was 147 mN (15 gf).

  Therefore, the tensile breaking strength when the filter 32 is hooked on the fourteen needle-claw-shaped projections 40f is 2.058 N (210 gf). For this reason, 1.96 N (200 gf), which is the drop strength standard of the filter 32 by the wind pressure of the blower fan, can be cleared.

  In the present embodiment, in order to make it more difficult for the filter 32 to drop off, measures have been taken to ensure the depth of the needle claw-shaped projections 40f even if the position of the filter 32 is shifted left and right and up and down.

  That is, as shown in FIG. 6, a plurality of needle claw-like projections 40f having sharp needle-like tip portions 40u are provided in the first and second frame portions 40a and 40b, respectively, as shown in FIG. They were linearly arranged along the peripheral parts 40m and 40w of 40g and 40d.

  Then, as shown in FIG. 9, the needle claw-shaped projections 40f provided on the first frame portion 40a side and the needle claw-shaped projections 40f provided on the second frame portion 40b side alternately have peaks and valleys. It was configured to be engaged.

  As shown in FIG. 9, the filter 32 is held from both sides by a needle claw-shaped protrusion 40f on the first frame portion 40a side and a needle claw-shaped protrusion 40f on the second frame portion 40b side. In this state, the limit load at which the fibers of the filter 32 are broken by the pressure acting in the direction of the arrow E in FIG. 9 and the filter 32 falls off the filter frame 40 is measured by a tension gauge. Thereby, the optimum shape of the air filter assembly 31 could be derived.

  As a target of the drop strength of the filter 32 held by the air filter assembly 31 of the present embodiment, the filter 32 does not fall even when a load of 4.9 N (500 gf) or more is applied.

  Consider an inner peripheral projection row 40x formed by a plurality of needle claw-shaped projections 40f provided on the second frame portion 40b. Further, an outer peripheral projection row 40y formed by a plurality of needle claw-shaped projections 40f provided on the outside is considered. Further, a projection row 40n formed by a plurality of needle claw-shaped projections 40f provided on the first frame portion 40a is considered. In each of these, eight needle claw-shaped projections 40f are provided for each one side to reduce variation in quality and secure a safety factor.

  In order to stabilize the amount of needle claw-shaped protrusions 40f that bite into the fibrous portion of the filter 32, the needle claw-shaped protrusions 40f provided on the first and second frame portions 40a and 40b shown in FIG. It is necessary to define the height L.

  The present inventors have determined the height L of the needle claw-shaped protrusion 40f in order to secure the amount of penetration of the needle claw-shaped protrusion 40f that bites into the fibrous portion of the filter 32. It was set to penetrate deeper.

  The range of the thickness H of the air filter assembly 31 is affected by the height H1 (the amount of depression) of the depression 32a at the center of the filter 32 shown in FIG. 9 from the surface of the valley 40p of the second frame portion 40b. Do not protrude. For this reason, the wavy shape of the filter 32 in a state where the filter 32 is sandwiched while being pressed so as to wavy in a gap between each of the needle claw-shaped protrusions 40f of each of the first and second frame portions 40a and 40b and the valley portion 40p therebetween. The height was about 3.5 mm.

  As a result, the needle claw 40f bites into the fibers of the filter 32 each time the filter 32 is used due to the restoring force of the filter 32, which is pressed and curved by the needle claw 40f, and the wind pressure of the blower fan.

  Then, the gaps between the valleys 40p and 40k between the plurality of needle claw-shaped projections 40f provided on the first frame portion 40a and the second frame portion 40b are defined. Thus, the filter 32 can be sandwiched and fixed between the first frame portion 40a and the second frame portion 40b without any trouble in assembling and without generating a resistance for passing the needle. Was.

  In this way, when the needle claw-shaped projections 40f of the filter frame 40 of the present embodiment are arranged, the falling strength of the filter 32 achieves 7.35N (750 gf), and the margin for the falling off of the filter 32 is obtained. ) Could be given.

<Locking part and locked part>
Next, referring to FIG. 7, the configuration of the locking portion and the locked portion having a function of preventing the filter frame 40 from opening when the filter 32 is sandwiched between the first frame portion 40a and the second frame portion 40b. explain.

  As shown in FIG. 7, the second frame portion 40b and the first frame portion 40a are fitted and locked. For this purpose, a locking claw 40h (locking portion) is provided on the peripheral edge of the first frame portion 40a. A fitting portion 40i (locked portion) to which the locking claw 40h is fitted and locked is provided on a peripheral portion of the second frame portion 40b.

  As shown in FIG. 7, the locking claw 40h of the present embodiment is configured such that, of the four sides of the first frame portion 40a, three sides other than the side on which the hinge portion 40j is provided are respectively inwardly directed from the outer peripheral frame 40r. It is extended.

  The locking claw 40h is provided at two places on the side opposite to the side where the hinge portion 40j is provided, and one locking claw 40h is provided on the other two sides.

  A fitting portion 40i is also provided on the peripheral portion of the second frame portion 40b so as to correspond to each locking claw 40h.

  As a result, a projection formed by a filter installation surface 40c2 provided on the second frame portion 40b shown in FIGS. 4 and 9 and a plurality of needle claw-like projections 40f serving as a filter pressing portion provided on the first frame portion 40a. The filters 32 sandwiched between the rows 40n are as follows.

  As shown in FIG. 7, each locking claw 40h provided on the first frame portion 40a is locked on a fitting portion 40i provided on the second frame portion 40b. Thereby, the second frame portion 40b and the first frame portion 40a are fitted on all sides other than the side connected by the hinge portion 40j, and it is possible to secure the holding force.

  As shown in FIG. 4, an arm 40q is provided on a filter mounting surface 40c1 of the first frame portion 40a on a straight line connecting the locking claws 40h provided on two opposite sides of the first frame portion 40a. Is provided.

<Filter replacement>
Next, a procedure for replacing the used dirty filter 32 in the air filter 13 shown in FIG. 3 will be described.

  First, without peeling the gap filling member 40e such as the sponge of the air filter 13 shown in FIG. 3, the outer peripheral frame of the side opposite to the side on which the hinge portion 40j of the first frame portion 40a shown in FIG. 7 is provided. A force is applied to deflect 40r outward.

  At this time, the two locking claws 40h provided on the top end of the outer peripheral frame 40r of the first frame portion 40a are respectively disengaged from the fitting portions 40i provided on the second frame portion 40b to release the fitting. Is done.

  Then, while pressing the arm 40q from the opposite side of the arm 40q and pressing the arm 40q, the second frame portion 40b is bent in the direction of arrow D in FIG. 8 by bending the flexible portion 40v about the hinge portion 40j. Move.

  At this time, a pair of fitting portions 40i of the second frame portion 40b provided at a position along the arm 40q of the first frame portion 40a are inclined at a predetermined inclination angle about the hinge portion 40j, and the first The pair of locking claws 40h of the frame portion 40a are lifted. Thereafter, the locking claws 40h are disengaged from the fitting portions 40i, and the engagement between all the locking claws 40h and the fitting portions 40i is released.

  Further, while pressing the arm 40q from the opposite side of the arm 40q and pressing the arm 40q, the second frame portion 40b is bent in the flexible portion 40v about the hinge portion 40j and turned in the direction of arrow D1 in FIG. To open the first frame portion 40a as shown in FIG.

  Thereafter, the used dirty filter 32 is removed, and a new filter 32 is fitted into the outer peripheral frame 40r of the first frame portion 40a.

  After exchanging the filter 32, the second frame portion 40b is again rotated in the direction of folding the flexible portion 40v about the hinge portion 40j in the direction of arrow D2 in FIG. 40a.

  At this time, the back surface of the fitting portion 40i of the second frame portion 40b abuts and slides on the curved surface 40h1 of the locking claw 40h of the first frame portion 40a shown in FIG. Then, the locking claw 40h of the first frame portion 40a is locked to the fitting portion 40i of the second frame portion 40b by going over the locking claw 40h. Thus, the used dirty filter 32 in the air filter 13 shown in FIG. 3 can be replaced.

  As described above, when the filter frame 40 is opened, only the operation of bending the first and second frame portions 40a and 40b is performed, and the locking claw 40h of the first frame portion 40a and the second frame portion 40b The engagement with the fitting portion 40i can be released.

  Accordingly, there is no need to release the plurality of locking claws 40h one by one, and the dirty filter 32 can be easily removed and replaced in a short time.

  The locking claw 40h is fitted together with the first frame 40a by assembling the second frame 40b by rotating the second frame 40b around the hinge 40j in the direction of arrow D in FIG. The part 40i is locked. Therefore, the assembling work of the air filter assembly 31 can be simplified, and the assembling work time can be reduced.

  Next, a procedure for installing or replacing the air filter 13 including the air filter assembly 31 in the main body of the image forming apparatus 30 according to the present embodiment will be described with reference to FIGS.

  First, as shown in FIG. 3, a gap filling member 40e made of an elastic member such as sponge is attached to the outer peripheral surface of the air filter assembly 31 holding the filter 32 by the filter frame 40 shown in FIG. To create the air filter 13.

  The air filter 13 of the present embodiment is an example in which a gap filling member 40e made of an elastic member is mounted on the outer peripheral surface 40r1 of the outer peripheral frame 40r of the first frame portion 40a.

  In addition, when the outer peripheral frame is also provided in the second frame portion 40b, the gap filling member 40e may be attached to the outer peripheral surface of the outer peripheral frame of the second frame portion 40b, The gap filling member 40e may be attached to both the outer peripheral surfaces of the outer peripheral frames of the two frame portions 40a and 40b. The gap filling member 40e can prevent the dust from leaking from the outer peripheral portion of the filter 32.

  Next, as shown in FIG. 2, the air filter 13 shown in FIG.

  Then, a filter case 60 provided with the air filter 13 shown in FIG. 3 is installed in an exhaust duct 61 installed on a side plate 41 of the image forming apparatus 30 via a duct support plate 62.

  When the image forming apparatus 30 is used, the filter 32 collects dust, and when replacing the dirty filter 32, the filter 32 is installed on the inner peripheral portion of the filter case 60 shown in FIG. The air filter 13 shown in FIG.

  Then, after replacing the dirty filter 32 of the air filter 13 with a new filter 32 in the above-described procedure, the air filter 13 is installed in the filter case 60 again.

  As shown in FIG. 8, the flexible portion 40v forming the hinge portion 40j of the filter frame 40 is extended at the top end of the outer peripheral frame 40r of the first frame portion 40a in the extending direction of the outer peripheral frame 40r (see FIG. 9). (In the thickness direction of the filter frame 40).

  As shown in FIG. 7, when the first frame portion 40a and the second frame portion 40b are closed, the outer peripheral surface 40r1 of the outer peripheral frame 40r of the first frame portion 40a shown in FIG. And the outer peripheral surface 40b1 of the frame portion 40b are arranged on the same plane. And hinge part 40j which consists of flexible part 40v which connects the 1st frame part 40a and the 2nd frame part 40b so that rotation is possible is arranged on the same surface.

  Thus, the hinge portion 40j does not protrude outward from the outer peripheral surface of the filter frame 40 (the outer peripheral frame 40r of the first frame portion 40a). Therefore, the hinge portion 40j does not interfere with the gap filling member 40e shown in FIG.

  Therefore, when installing or replacing the filter 32, there is no need to remove or re-install the gap filling member 40e shown in FIG.

  In the present embodiment, the first frame portion 40a and the second frame portion 40b are integrally formed. Then, the first frame portion 40a and the second frame portion 40b are turned around the hinge portion 40j to be folded, with the flexible portion 40v formed of the thin portion as the hinge portion 40j. Thus, the filter 32 is configured to be sandwiched from both sides.

  As another configuration, the first frame portion 40a and the second frame portion 40b can be configured separately. Then, a projection row 40n in which a plurality of needle claw-shaped projections 40f are arranged in a row is provided on the first frame portion 40a. Further, an inner peripheral projection row 40x in which a plurality of needle claw-like projections 40f are arranged in a row and an outer peripheral projection row 40y provided outside the second frame section 40b are provided. A similar effect can be obtained with such a configuration.

  Further, in the present embodiment, as shown in FIG. 6, an example in which the needle claw-shaped projection 40f is formed in a substantially quadrangular pyramid shape has been described. The shape of the needle claw-shaped protrusion 40f may be a triangular pyramid shape or a conical shape, and the needle-shaped tip portion 40u of the needle claw-shaped protrusion 40f enters the fibrous portion of the filter 32. It suffices if the displacement can be prevented.

  In addition, as shown in FIG. 9, a projection row in which a plurality of needle claw-shaped projections 40f formed on the first frame section 40a side and the second frame section 40b side, respectively, is considered. Among them, it is sufficient that at least one of the projection rows 40n is sandwiched between the other inner projection row 40x and the outer projection row 40y provided outside thereof from both sides. The projection row 40n on the side to be sandwiched need not be a single row.

  That is, a plurality of projection rows in which a plurality of needle claw-shaped projections 40f formed respectively on the first frame section 40a side and the second frame section 40b side are arranged in a row, such as two rows or three rows. And A plurality of rows of projections that are interleaved with each other in a comb shape may be provided on both the first frame portion 40a and the second frame portion 40b.

  Further, as shown in FIG. 4, in the present embodiment, the first frame portion 40a and the second frame portion 40b are provided with rectangular openings 40d and 40g, respectively, and the peripheral portions 40m and 40w around the openings are formed. An example in which the filter mounting surfaces 40c1 and 40c2 are configured has been described. Alternatively, the openings 40d and 40g may be formed in a perfect circular shape, an elliptical shape, or a polygonal shape other than a square shape.

  Further, as shown in FIG. 4, in the present embodiment, a projection row 40n in which a plurality of needle claw-shaped projections 40f provided on the first and second frame portions 40a and 40b are arranged in a row, an inner circumference projection row. 40x and the outer peripheral projection row 40y are as follows. An example has been described in which the rectangular openings 40d and 40g are arranged so as to surround the entire periphery of the peripheral edges 40m and 40w, respectively.

  In addition, it is only necessary that the filter 32 can be securely held by being sandwiched between the respective projection rows. The height L of the needle claw-shaped projections 40f of each projection row, the sharpness and rigidity of the needle-shaped claw-shaped protrusions 40u, the frictional characteristics of the surface of the needle claw-shaped protrusions 40f, and the number of arranged needle-shaped crests 40u And the arrangement density are appropriately set. Thereby, the optimal holding force of the filter 32 can be appropriately set.

  Therefore, each projection row may be arranged on a part of the entire periphery of the peripheral portions 40m and 40w of the openings 40d and 40g. That is, of the projection row 40n, the inner circumference projection row 40x, and the outer circumference projection row 40y in which the plurality of needle claw-shaped projections 40f are arranged in a row, a part or all of the circumference of each of the quadrangular openings 40d, 40g is formed. For example, a configuration provided on only three sides of the four sides of the peripheral portions 40m and 40w may be employed.

  For example, a configuration in which each projection row is provided in, for example, a semicircular portion or a range of about 3/4 of the entire circumference of the peripheral portions 40m and 40w of the perfect circular openings 40d and 40g may be used.

  In addition, the arrangement pitch (density) of the needle claw-like projections 40f, the respective projection rows 40n, the inner circumference projection rows 40x, and the outer circumference projection rows 40y does not need to be particularly constant, and may vary depending on the location where the random pitch or change rate varies. It may be a fixed one. In addition, the height L of the needle claw-shaped projections 40f of each projection row, the sharpness and rigidity of the needle-shaped tip portions 40u of the needle claw-shaped projections 40f, the frictional characteristics of the surface of the needle claw-shaped projections 40f, and the like are also mechanical. Optimal specifications for the characteristics can be appropriately selected.

  In this embodiment, it is not necessary to perform a special hole processing on the filter 32 obtained by cutting a flat nonwoven fabric having a thickness of 2 mm to 5 mm into a square.

  Furthermore, the filter frame 40 holding the filter 32 can be opened with one touch, and the filter frame 40 can be engaged with the first and second frame portions 40a and 40b by snap fit so that the dirty filter 32 can be easily detached and replaced. A stop claw 40h and a fitting portion 40i are provided.

  Further, even when the filter 32 is inadvertently detached from the filter frame 40 during use or during attachment / detachment or external force such as wind pressure from an exhaust fan is applied, the filter 32 does not bend and expand or fall off the filter frame 40.

  The material of the filter 32 made of a nonwoven fabric has been subjected to various types of fraying prevention processing for preventing movement between the fibers so that the fibers do not fall off. This makes it difficult to penetrate the filter 32 with a large resistance even if a needle or the like is inserted.

  For this reason, conventionally, a fixing method was used in which a filter 32 was previously formed with holes or used for sticking with a double-sided tape or the like.

  In the present embodiment, as shown in FIG. 9, a filter mounting surface 40c2 provided on the second frame portion 40b for holding the filter 32, and a plurality of filters provided on the first frame portion 40a serving as a filter holding portion. And a projection row 40n formed by the needle claw-shaped projections 40f. The filter 32 can be held by sandwiching the filter 32 between the filter installation surface 40c2 and the projection row 40n.

  Further, as shown in FIG. 4, needle claw-shaped protrusions 40f having sharp needle-shaped tips 40u are arranged in a row at predetermined intervals on the peripheral edge 40m of the opening 40g of the first frame portion 40a. A projection row 40n was provided. Further, an inner peripheral projection row 40x formed by a plurality of needle claw-shaped projections 40f provided on the second frame portion 40b is provided. Further, an outer peripheral projection row 40y is provided on the outer periphery.

  As a result, as shown in FIG. 9, the needle-like tip 40u of the needle claw-like projection 40f reliably enters and is caught by the fibers on the surface of the filter 32, and the filter 32 can be prevented from slipping. As a result, the falling resistance of the filter 32 can be increased.

  In addition, from the viewpoint of the ecology of material separation (conservation of natural environment), the used filter cannot be separated from the resin frame, which is a drawback of the integrated filter in which the thin sheet filter is conventionally formed by outsert molding of resin. Take into account. In the present embodiment, only the filter 32 can be removed from the filter frame 40 and discarded. This makes it possible to provide a filter 32 that is more environmentally friendly.

  Conventionally, when performing maintenance of the image forming apparatus 30 at a market user using the image forming apparatus 30, a resin-integrated filter has been replaced as a service component. In the present embodiment, only the filter 32 alone can be replaced. As a result, it is possible to reduce the burden on maintenance because it is lighter without taking up space for carrying or transporting.

  Next, a configuration of an air filter assembly according to the present invention and an image forming apparatus including the air filter assembly according to a second embodiment will be described with reference to FIGS. The same components as those in the first embodiment have the same reference numerals or the same reference numerals, even if the reference numerals are different.

  FIG. 11 is a perspective explanatory view showing the configuration of the filter frame 50 of the air filter assembly 31 of the present embodiment.

  FIG. 12 considers a state in which the first frame portion 50a and the second frame portion 50b constituting the filter frame 50 of the air filter assembly 31 of the present embodiment are closed. And it is sectional explanatory drawing which shows the state which the filter 32 was pinched between the 1st frame part 50a and the 2nd frame part 50b.

  In the first embodiment, as shown in FIG. 5, an inner peripheral projection row 40x formed by a plurality of needle claw-shaped projections 40f provided on a second frame portion 40b, and an outer peripheral projection row 40y provided outside the same. The shape and height L of each of the needle claw-shaped projections 40f are the same.

  In the present embodiment, as shown in FIGS. 11 and 12, the shape of each needle claw-like projection 50f constituting an inner circumferential projection row 50x formed by a plurality of needle claw-like projections 50z provided on the second frame portion 50b And the height L1 are as follows. The shape and height L2 of each needle claw-like projection 50f constituting the outer peripheral projection row 50y provided on the outside are set to be lower than the height L2.

  As shown in FIG. 11, a projection row 50n in which a plurality of needle claw-shaped projections 50f are arranged in a row at a predetermined interval is provided on the entire periphery of the peripheral edge 50m of the opening 50g of the first frame section 50a. Is provided.

  Similarly, an inner peripheral projection row 50x in which a plurality of needle claw-shaped projections 50z are arranged in a row at predetermined intervals is provided on the entire periphery of the peripheral edge 50w of the opening 50d of the second frame section 50b. I have.

  Further, on the outer peripheral portion of the inner peripheral projection row 50x, a plurality of needle claw-like projections 50f are arranged at predetermined intervals, similarly to the inner peripheral projection row 50x, with the valley portion 50k shown in FIGS. An outer peripheral projection row 50y arranged in a shape is provided.

  The shape of the needle claw-shaped protrusion 50f of the present embodiment is exactly the same as the shape of the needle claw-shaped protrusion 40f of the first embodiment shown in FIG. 6 and described above.

  The shape of the needle claw-shaped protrusion 50z of the present embodiment is substantially a quadrangular pyramid like the needle claw-shaped protrusion 40f shown in FIG. 6 and described above. Then, as shown in FIGS. 11 and 12, the height of the needle claw-shaped projection 50f constituting the outer peripheral projection row 50y of the present embodiment is L2, whereas the needle claw constituting the inner peripheral projection row 50x. The height L1 of the projection 50z is set in the relationship shown in the following equation (1).

[Equation 1]
L1 <L2

  The needle claw-shaped projections 50f and 50z of the present embodiment close the first frame portion 50a and the second frame portion 50b similarly to the first embodiment. At this time, as shown in FIG. 12, the needle claw-shaped projection 50f of the first frame portion 50a and the valley portion 50p of the second frame portion 50b are arranged so as to face and mesh with each other. In addition, the needle claw-shaped projections 50f, 50z of the second frame portion 50b and the valley portion 50p of the first frame portion 50a are arranged so as to face and mesh with each other.

  Further, as shown in FIG. 12, the inner peripheral projection row 50x and the outer peripheral projection row 50y provided on the second frame section 50b side sandwich the projection row 50n provided on the first frame section 50a side. Be placed.

That is, Kakuharitsume as a valley portion 50k between the inner peripheral protruding rib 50x and the outer protruding ribs 50y of the second frame portion 50b, and a protruding rib 50n of the first frame portion 5 0a engages opposed The projections 50f and 50z are arranged.

  Thus, similarly to the first embodiment shown in FIG. 10 and described above, the needle claw-shaped projections 50f and 50z formed on the first and second frame portions 50a and 50b are moved in the vertical and horizontal directions in FIG. Each of them is shifted from each other.

  FIG. 12 shows a state in which the filter 32 is held by the needle claw-shaped projections 50f and 50z formed on the first and second frame portions 50a and 50b, respectively.

  At this time, the projection formed by each of the needle claw-shaped projections 50f of the first frame portion 50a from the upper portion of the filter 32 in the direction of arrow E in FIG. It presses so that row 50n may be pinched.

  This prevents the filter 32 from being displaced in a direction orthogonal to the pressing direction indicated by the arrow E in FIG.

  The needle-like tip 50u of each needle claw-like projection 50f forming the projection row 50n of the first frame 50a penetrates deeply into the fibrous portion of the filter 32. Thereby, the filter 32 can be held efficiently.

  Further, the filter 32 is securely held by the projection row 50n of the first frame portion 50a. Accordingly, the inner peripheral projection row 50x and the outer peripheral projection row 50y of the second frame portion 50b arranged on both sides of the projection row 50n can also reliably enter the fibrous portion of the filter 32.

  As shown in FIG. 12, the needle-like tip portions 50u of all the needle claw-like projections 50f, 50z bite into the filter 32. Then, similarly to the first embodiment, the peripheral portions of the four sides of the filter 32 are formed into a substantially “H” shape which is convex upward in FIG. 12 by the pressing force of the inner peripheral projection row 50x of the second frame portion 50b. Bend.

  As shown in FIG. 12, the needle claw-shaped projections 50f, 50z do not exist inside the inner peripheral projection row 50x of the second frame portion 50b. Therefore, in the center of the filter 32, as shown in FIG. 12, a recess 32a is formed, which is recessed by the height H2 from the surface of the filter installation surface 50c2 of the second frame 50b.

  Here, the height L1 from the filter installation surface 50c2 of the needle claw-shaped projection 50z constituting the inner peripheral projection row 50x of the second frame portion 50b and the filter installation of the needle claw-shaped projection 50f constituting the outer peripheral projection row 50y. The height L2 from the surface 50c2 is set to the relationship shown in Expression 1 above.

  For this reason, the height H1 at which the center of the filter 32 is recessed from the filter installation surface 40c2, which is the amount of depression of the filter 32 in the case of the first embodiment shown in FIG. 9, is considered. Further, the height H2 of the center of the filter 32 from the filter installation surface 50c2, which is the amount of depression of the filter 32 in the case of the present embodiment shown in FIG. 12, is taken into consideration. Both are set in a relationship represented by the following equation (2).

[Equation 2]
H1> H2

  That is, in the present embodiment, the filter 32 is held from both sides by the respective needle claw-shaped projections 50f, 50z formed on the first and second frame portions 50a, 50b. The height H2 where the center of the filter 32 is depressed from the filter installation surface 50c2, which is the depressed amount in that state, is as follows.

  The central part of the filter 32 from the filter installation surface 40c2 in the case of the first embodiment is suppressed to be lower than the recessed height H1. Thereby, the flatness of the filter 32 held in the filter frame 50 is ensured.

  The filter 32 has various rigidities (strength of the waist) depending on a difference in a material, a thickness, and the like. In the case of the soft filter 32 having a low rigidity (strength of the waist), as in the present embodiment, the needle claw-shaped projection 50z constituting the inner peripheral projection row 50x of the second frame portion 50b from the filter mounting surface 50c2. The height L1 is set lower than the height L2 of the other needle claw-shaped projection 50f. Thereby, the flatness of the filter 32 held in the filter frame 50 can be improved.

  Thereby, good dust collection filtration performance can be maintained without impairing the air permeability to the filter 32.

  Further, good mechanical performance and assembly operability can be provided without applying unnecessary stress load to the filter 32 when assembling the air filter assembly 31.

  In FIGS. 11 and 12, reference numeral 50c1 denotes a filter installation surface on the first frame portion 50a side. 50h is a locking claw, and 50h1 is a curved surface of the locking claw 50h.

  50i is a fitting portion, 50j is a hinge portion, 50q is an arm, and 50r is an outer peripheral frame provided on the first frame portion 50a. 50v is a flexible part. Other configurations are the same as those of the first embodiment, and the same effects can be obtained.

31 air filter assembly 32 filter 40a first frame portion 40b second frame portion 40d opening provided in second frame portion 40b (second opening)
40g... Opening of first frame portion 40a (first opening)
40m... Peripheral portion 40n of opening 40g... Protrusion row 40w formed by a plurality of needle claw-like protrusions 40f provided on first frame portion 40a... Peripheral portion 40x of opening 40d. Inner peripheral projection row 40y formed by the needle claw-shaped projections 40f of the outer peripheral projection row formed by the plurality of needle claw-shaped projections 40f provided on the second frame portion 40b

Claims (7)

Filters and
A filter frame for holding the filter,
An air filter assembly having
The filter frame includes:
A first frame portion having a first opening for ventilating the filter,
Having a second opening to vent the filter, a second frame portion configured to be openable and closable with respect to the first frame portion,
Has,
The first frame portion has a projection row in which a plurality of needle claw-shaped projections are arranged in a row at intervals on at least a part of a peripheral portion of the first opening,
The second frame portion,
An inner peripheral projection row in which a plurality of needle claw-shaped projections are arranged in a row at intervals on at least a part of the peripheral edge of the second opening,
An outer peripheral projection row in which a plurality of needle claw-shaped projections are arranged in a row at intervals on at least a part of the outer circumference of the inner peripheral projection row,
Has,
When the first frame portion and the second frame portion are closed, the inner peripheral projection row and the outer peripheral projection row sandwich the projection row from both sides and mesh the filter. An air filter assembly characterized by holding.   2. The air filter assembly according to claim 1, wherein a height of the needle claw-shaped projections in the inner peripheral projection row is lower than a height of the needle claw-shaped projections in the outer peripheral projection row. 3.   The air filter assembly according to claim 1, wherein the filter is made of a flat fibrous nonwoven fabric, and the needle claw-like projections bite into a fibrous portion of the filter. The first frame portion, further comprising a hinge portion rotatably connecting the second frame portion ,
When the first frame portion and the second frame portion are closed, the outer peripheral surface of the first frame portion and the outer peripheral surface of the second frame portion are arranged on the same plane. ,
The air filter assembly according to any one of claims 1 to 3, wherein the hinge portion is disposed on the same surface so as not to protrude outward from an outer peripheral surface of the filter frame .   A locking portion is provided on one of the first frame portion and the second frame portion, and a locked portion with which the locking portion is engaged is provided on the other. The air filter assembly according to claim 1.   The gap filling member made of an elastic member is mounted on one of an outer peripheral surface of the first frame portion and an outer peripheral surface of the second frame portion, according to any one of claims 1 to 5, wherein An air filter assembly according to any of the preceding claims.   An image forming apparatus comprising the air filter assembly according to claim 1, wherein the image forming apparatus forms an image on a recording material.