FILTER HOLDING DEVICE, DEVELOPING DEVICE, PROCESS CARTRIDGE, AND IMAGE FORMING APPARATUS

Abstract

To prevent an object of discharge from being discharged together with an object of collection.SOLUTION: A filter 26t has a first side and a second side. The weight density of the first side per unit volume is smaller than the weight density of the second side per unit volume. The filter 26t has, on the surface of the second side, a sticker 26u that can be stuck to a stopper 26r (sticking object).SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] This invention is a method for collecting and aerating a toner or other object to be collected. Equipped with a filter The present invention relates to a filter holding device, a developing device containing toner, a process cartridge, and an image forming apparatus. [Background technology]

[0002] Conventionally, in developing devices installed in image forming devices such as copiers and printers, a technique has been known in which a filter is installed in an opening formed in the upper part of a developing case in order to prevent toner from scattering due to an increase in internal pressure within the device (see, for example, Patent Document 1).

[0003] More specifically, in the developing device of Patent Document 1, even if the internal pressure of the device is about to rise, the air inside the device is discharged to the outside of the device through an opening where a filter is installed, so the internal pressure rise is suppressed. And even if the toner floating inside the device is about to be discharged to the outside of the device together with the air when the air inside the device is discharged to the outside of the device in this way, the toner is captured by the filter, so the toner is prevented from scattering outside the device. Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional technology, there was a possibility that the toner (collection target) inside the device would leak out from the side of the filter together with the air (discharge target). In such a case, the filter would not function properly and the toner (collection target) would scatter outside the device.

[0005] The present invention has been made to solve the above-mentioned problems, and is intended to reduce the inconvenience of the discharge object being discharged together with the capture object. A filter retaining device, A developing device, a process cartridge, and an image forming apparatus. [Means for solving the problem]

[0006] The filter of the present invention is provided with a filter that is installed in an opening that communicates between the inside of the device and the outside of the device, and is formed so that the weight density per unit volume at one end is lower than the weight density per unit volume at the other end, the opening has an edge extending in a direction from the inside of the device to the outside of the device, the filter has an attachment part formed around the surface of the other end that can be attached to an attachment member, and is fitted into the edge so that the one end is located on the inside of the device and is the upstream side in the ventilation direction, and the other end is located on the outside of the device and is the downstream side in the ventilation direction, but The adhesive tape is attached to the attachment member on the outside of the device. Effect of the Invention

[0007] According to the present invention, the problem that the discharge object is discharged together with the collection object is reduced. A filter holding device It is possible to provide a developing device, a process cartridge, and an image forming apparatus. [Brief description of the drawings]

[0008] [Figure 1] 1 is an overall configuration diagram showing an image forming apparatus according to an embodiment of the present invention; [Diagram 2] FIG. [Diagram 3] FIG. 2 is a diagram showing the developing device in the longitudinal direction. [Figure 4] 1A is an enlarged cross-sectional view showing a state in which a filter is installed in the opening of the developing device, and FIG. 1B is an enlarged cross-sectional view showing a state before the filter is installed in the opening of the developing device. [Diagram 5] 1A shows a top view and FIG. 1B shows a cross-sectional side view of the filter. [Figure 6] FIG. 4 is a schematic enlarged view showing the ventilation state at the opening. [Figure 7] As a first modified example, (A) is an enlarged cross-sectional view showing a state in which a filter is installed in an opening of a developing device, and (B) is an enlarged cross-sectional view showing a state before the filter is installed in the opening of the developing device. [Figure 8] FIG. 11 is an enlarged view showing a state in which a filter is installed at an opening of a developing device according to a second modified example. [Figure 9] FIG. 11 is an enlarged view showing a state in which a filter is installed at an opening of a developing device according to a third modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and the duplicated description will be appropriately simplified or omitted.

[0010] First, the overall configuration and operation of an image forming apparatus 1 will be described with reference to FIG. The image forming apparatus 1 in this embodiment is a tandem type color image forming apparatus in which a plurality of process cartridges 20Y, 20M, 20C, and 20BK are arranged side by side so as to face an intermediate transfer belt 40. In addition, a developing device 26 (see FIG. 2) serving as a filter holding device (device with a filter) is provided so as to face the photosensitive drums 21 of the plurality of process cartridges 20Y, 20M, 20C, and 20BK.

[0011] In FIG. 1, reference numeral 1 denotes the main body of a color copier as an image forming device, 2 denotes an original transport section which transports an original to an original reading section 3, 3 denotes an original reading section which reads image information of the original, and 4 denotes a writing section (exposure section) which emits laser light based on input image information. Also, 20Y, 20M, 20C, and 20BK denote process cartridges corresponding to the respective colors (yellow, magenta, cyan, and black), and 40 denotes an intermediate transfer belt onto which toner images of a plurality of colors are transferred in an overlapping manner. Also, 61 denotes a paper feeding device in which sheets P such as paper are stored, 65 denotes a secondary transfer roller that transfers the toner image formed on the intermediate transfer belt 40 onto the sheet P, and 66 denotes a fixing device that fixes an unfixed image on the sheet P. In addition, reference numeral 70 denotes a toner container for replenishing toner of each color to each developing device 26 corresponding to the multiple process cartridges 20Y, 20M, 20C, and 20BK, and reference numeral 80 denotes a waste toner collection container in which untransferred toner collected by the cleaning device 23 (see FIG. 2) or the intermediate transfer belt cleaning device 81 is collected as waste toner.

[0012] 2, each of the process cartridges 20Y, 20M, 20C, and 20BK is an integral unit of a photosensitive drum 21 as an image carrier, a charging device 22, and a cleaning device 23. When each of the process cartridges 20Y, 20M, 20C, and 20BK reaches the end of its life, it is removed from the image forming apparatus main body 1 and replaced with a new one. Each developing device 26 is disposed so as to face the photosensitive drum 21 of each process cartridge 20Y, 20M, 20C, 20BK. When the developing device 26 reaches the end of its life, it is removed from the image forming apparatus main body 1 and replaced with a new one. The operation of attaching and detaching the developing device 26 to and from the image forming apparatus main body 1 and the operation of attaching and detaching the process cartridges 20Y, 20M, 20C, 20BK to and from the image forming apparatus main body 1 can be performed separately and independently. A toner image of each color (yellow, magenta, cyan, black) is formed on the photosensitive drum 21 (image carrier) of each of the process cartridges 20Y, 20M, 20C, and 20BK.

[0013] Hereinafter, the operation of the image forming apparatus during normal color image formation will be described. First, the document is transported from the document table by the transport rollers of the document transport unit 2 and placed on the contact glass of the document reading unit 3. Then, the document reading unit 3 optically reads image information of the document placed on the contact glass. Then, the image information of each color of yellow, magenta, cyan, and black is transmitted to the writing unit 4. Then, from the writing unit 4, laser light L (exposure light) based on the image information of each color is irradiated toward the surface of the photosensitive drum 21 (see FIG. 2) of the corresponding process cartridge 20Y, 20M, 20C, and 20BK.

[0014] Meanwhile, each of the four photoconductor drums 21 rotates in a clockwise direction in Fig. 1 and Fig. 2. First, the surface of the photoconductor drum 21 is uniformly charged at a position facing the charging device 22 (charging roller) (charging process). In this way, a charging potential is formed on the photoconductor drum 21. Thereafter, the charged surface of the photoconductor drum 21 reaches a position irradiated with laser light by each writing unit 4, and an electrostatic latent image based on image information is formed at that position (exposure process).

[0015] The laser light corresponding to the yellow component is irradiated onto the surface of the photoconductor drum 21 of the first process cartridge 20Y from the left side of the drawing. At this time, the laser light of the yellow component is scanned in the direction of the rotation axis (main scanning direction) of the photoconductor drum 21 by a polygon mirror rotating at high speed. In this way, an electrostatic latent image corresponding to the yellow component is formed on the photoconductor drum 21 after it has been charged by the charging device 22. Similarly, the cyan laser light is irradiated onto the surface of the photoconductor drum 21 of the second process cartridge 20C from the left on the paper, forming an electrostatic latent image of the cyan component. The magenta laser light is irradiated onto the surface of the photoconductor drum 21 of the third process cartridge 20M from the left on the paper, forming an electrostatic latent image of the magenta component. The black laser light is irradiated onto the surface of the photoconductor drum 21 of the fourth process cartridge 20BK from the left on the paper, forming an electrostatic latent image of the black component.

[0016] Thereafter, the surface of the photoconductor drum 21 on which the electrostatic latent images of each color are formed reaches a position facing the developing device 26. Then, toner of each color is supplied from each developing device 26 onto the photoconductor drum 21, and the latent images on the photoconductor drum 21 are developed (this is the developing process). Thereafter, the surfaces of the photoconductor drums 21 after the developing process reach positions facing the intermediate transfer belt 40. Here, primary transfer rollers 24 are provided at each of the facing positions so as to abut against the inner circumferential surface of the intermediate transfer belt 40. Then, at the positions of the primary transfer rollers 24, the toner images of each color formed on the photoconductor drums 21 are transferred onto the intermediate transfer belt 40 in order, superimposed on top of each other (this is the primary transfer process).

[0017] Then, the surfaces of the photoconductor drums 21 after the primary transfer process reach a position facing the cleaning device 23. Then, the cleaning device 23 collects the untransferred toner remaining on the photoconductor drums 21 (cleaning process). The untransferred toner collected by the cleaning device 23 passes through a waste toner transport path (not shown) and is collected in the waste toner collection container 80. Thereafter, the residual potential on the surface of the photosensitive drum 21 is removed at the position of the charge removing device, and a series of image forming processes on the photosensitive drum 21 is completed.

[0018] On the other hand, the surface of the intermediate transfer belt 40 onto which the images of each color on the photoconductor drum 21 are transferred and superimposed runs in the direction of the arrow in the figure and reaches the position of the secondary transfer roller 65. Then, at the position of the secondary transfer roller 65, the full-color image on the intermediate transfer belt 40 is secondarily transferred onto the sheet P (secondary transfer process). Thereafter, the surface of the intermediate transfer belt 40 reaches the position of the intermediate transfer belt cleaning device 81. Then, the untransferred toner on the intermediate transfer belt 40 is collected by the intermediate transfer belt cleaning device 81, and a series of transfer processes on the intermediate transfer belt 40 is completed. The untransferred toner collected by the intermediate transfer belt cleaning device 81 passes through a waste toner transport path (not shown) and is collected in a waste toner collection container 80.

[0019] Here, the sheet P conveyed to the position of the secondary transfer roller 65 is conveyed from the paper feeder 61 via the registration roller 64 and the like. Specifically, the sheet P fed by a feed roller 62 from a sheet feeder 61 that stores the sheet P passes through a conveying path and is then guided to the position of a registration roller 64. The sheet P that has reached the position of the registration roller 64 is conveyed toward the position of a secondary transfer roller 65 in synchronization with the toner image on the intermediate transfer belt 40.

[0020] Thereafter, the sheet P onto which the full-color image has been transferred is guided to the position of the fixing device 20. Then, in the fixing device 20, the color image is fixed onto the sheet P at the nip between a fixing roller and a pressure roller. After the fixing process, the sheet P is discharged as an output image outside the apparatus main body 1 by a discharge roller 69, and is then stacked on the discharge tray 5, completing a series of image forming processes.

[0021] Next, the image forming unit of the image forming apparatus will be described in detail with reference to FIG. 2 and FIG. In addition, the four image-forming units installed in the image forming apparatus main body 1 have almost the same structure except for the color of toner used in the image-forming process, so they are illustrated without the alphabetical symbols (Y, M, C, BK) for components such as process cartridges and developing devices.

[0022] As shown in FIG. 2, the process cartridge 20 mainly includes a photosensitive drum 21 as an image carrier, a charging device 22, and a cleaning device 23 housed integrally in a case. The photoconductor drum 21 is a negatively charged organic photoconductor, and is configured by providing a photosensitive layer and the like on a drum-shaped conductive support. The charging device 22 is a charging roller in which a medium-resistance elastic layer is coated on the outer periphery of a conductive core metal. A predetermined voltage is applied from a power supply unit to the charging device 22 (charging roller), thereby uniformly charging the surface of the opposing photoconductor drum 21. The cleaning device 23 is provided with a cleaning blade 25a and a cleaning roller 25b that come into contact with the photoreceptor drum 21. The cleaning blade 25a is made of a rubber material such as urethane rubber, and comes into contact with the surface of the photoreceptor drum 21 at a predetermined angle and with a predetermined pressure. The cleaning roller 25b is a brush roller with brush bristles arranged around a core metal.

[0023] As shown in Figures 2 and 3, the developing device 26 is mainly composed of a developing roller 26a as a developer carrier, a first transport screw 26b1 (first transport member) facing the developing roller 26a, a second transport screw 26b2 (second transport member) facing the first transport screw 26b1 via a partition member 26e, and a doctor blade 26c (developer regulating member) facing the developing roller 26a and regulating the amount of developer carried on the developing roller 26a. Incidentally, the developing device 26 in this embodiment also functions as a filter holding device that holds the filter 26t (toner filter), which will be described in detail later.

[0024] The developing device 26 contains a developer (two-component developer) made up of a carrier and a toner. The developing roller 26a is configured to form a developing area by facing the photosensitive drum 21 with a small gap therebetween. As shown in Fig. 3, the developing roller 26a is configured with a magnet 26a1 that is fixed inside and forms multiple poles (magnetic poles) on the outer circumferential surface of the roller, and a sleeve 26a2 that rotates around the magnet 26a1.

[0025] The transport screws 26b1 and 26b2 as transport members transport the developer contained inside the developing device 26 in the longitudinal direction to form a circulation path (a circulation path indicated by a dashed arrow in FIG. 3). That is, a circulation path for the developer is formed by a first transport path B1 formed by the first transport screw 26b1 and a second transport path B2 formed by the second transport screw 26b2. The first transport path B1 and the second transport path B2 are separated by a partition member 26e (wall portion), and both ends of the two transport paths B1 and B2 in the longitudinal direction communicate with each other via communication openings 26f and 26g. Specifically, referring to FIG. 3, the upstream end of the first transport path B1 in the transport direction communicates with the downstream end of the second transport path B2 in the transport direction via the first communication opening 26f. Also, the downstream end of the first transport path B1 in the transport direction communicates with the upstream end of the second transport path B2 in the transport direction via the second communication opening 26g. That is, the partition member 26e is disposed at a position excluding both ends in the longitudinal direction. The first transport screw 26b1 (first transport path B1) is disposed so as to face the developing roller 26a, and the second transport screw 26b2 (second transport path B2) is disposed so as to face the first transport screw 26b1 (first transport path B1) via a partition member 26e. The first transport screw 26b1 transports the developer in the longitudinal direction while supplying the developer toward the developing roller 26a and recovering the developer after the developing process that has been separated from the developing roller 26a. The second transport screw 26b2 stirs and mixes the developer after the developing process transported from the first transport path B1 and fresh toner supplied from the supply port 26d while transporting them in the longitudinal direction. In this embodiment, the two conveying screws 26b1 and 26b2 are arranged side by side in the horizontal direction. Each of the two conveying screws 26b1 and 26b2 has a screw portion wound around a rotating shaft.

[0026] The above-mentioned image forming process will now be described in more detail, focusing on the development process. The developing roller 26a rotates in the direction of the arrow in Fig. 2. As shown in Fig. 3, the developer in the developing device 26 circulates in the longitudinal direction while being stirred and mixed with the toner supplied from the toner container 70 through the toner supply port 26d via the toner supply path by the rotation in the direction of the arrow of the first transport screw 26b1 and the second transport screw 26b2, which are arranged with a partition member 26e interposed therebetween (circulation in the direction of the dashed arrow in Fig. 3). The toner that is frictionally charged and attracted to the carrier is lifted up onto the developing roller 26a together with the carrier by the developer lifting pole formed on the developing roller 26a. The developer carried on the developing roller 26a is transported in the direction of the arrow in FIG. 2 to reach a position facing the doctor blade 26c. The developer on the developing roller 26a is then transported to a position facing the photoconductor drum 21 (the developing area) after the amount of developer on the developing roller 26a is adjusted to an appropriate amount at this position. The toner is then attracted to the latent image formed on the photoconductor drum 21 by the electric field formed in the developing area. After that, the developer remaining on the developing roller 26a reaches above the first transport path B1 as the sleeve rotates, and is released from the developing roller 26a at this position. Here, the electric field in the developing area is formed by a predetermined voltage (developing bias) applied to the developing roller 26a by the power source for development, and a surface potential (latent image potential) formed on the surface of the photoconductor drum 21 by the charging process and the exposure process.

[0027] The toner in the toner container 70 is appropriately replenished into the developing device 26 from the replenishing port 26d via a toner replenishing path (not shown) as the toner in the developing device 26 is consumed. The consumption of the toner in the developing device 26 is detected by a toner concentration sensor (not shown) that magnetically detects the toner concentration of the developer in the developing device 26 (the ratio of toner in the developer). The supply port 26d is provided at one end of the second conveying screw 26b2 in the longitudinal direction (the left-right direction in FIG. 3) and above the second conveying screw 26b2 (second conveying path B2).

[0028] The filter 26t and the developing device 26 serving as a filter holding device, which are characteristic of this embodiment, will be described in detail below. 2, 4(A), etc., the developing device 26 in this embodiment also functions as a filter holding device in which a filter 26t is installed in an opening 26k1 that connects the inside of the device to the outside of the device. In FIG. 4, the upper side of the developing case 26k is the outside of the device (the outside of the developing device 26), and the lower side is the inside of the device (the inside of the developing device 26). More specifically, an opening 26k1 (ventilation path) penetrating from inside to outside is formed in the ceiling of the development case 26k (housing) of the development device 26. A filter 26t is provided to close the opening 26k1. The filter 26t is for collecting toner as powder and for allowing air to pass through. In other words, an opening 26k (ventilation path) for sending air in a ventilation direction from the inside of the developing device 26 to the outside is formed in the developing case 26k. The filter 26t is installed at the opening 26k. The filter 26t is made of a mesh smaller than the particle size of the toner T and carrier C, and is formed so that only air can pass through. In this embodiment, the opening 26k1 is opened in a substantially rectangular shape, and the filter 26t (in a stand-alone state) is formed in a substantially rectangular parallelepiped shape, but the shapes of the opening 26k1 and the filter 26t are not limited to those in this embodiment. In that case, the shape of the annular attachment part 26u described later will also match the shape of the ventilation surface of the filter 26t (for example, if the ventilation surface of the filter 26t is circular, the attachment part 26u will be circular).

[0029] Here, the gap H (casing gap) between the developing roller 26a and the developing case 26k on the downstream side of the developing area is set to be within the range of 0.6 to 1.0 mm. If the casing gap H becomes smaller than 0.6 mm, the developer carried by the developing roller 26a after the development process is not smoothly transported to the gap H between the developing roller 26a and the developing case 26k, and is likely to overflow and leak out of the developing device 26. On the other hand, if the casing gap H is larger than 1.0 mm, the developer carried by the developing roller 26a will have difficulty sliding against the inner surface of the developing case 26k, making it difficult for the pump action to form an intake airflow toward the inside of the developing device 26, and toner scattering from the developing device 26 (toner scattering around the development area) will be more likely to occur. By maintaining the casing gap H within an appropriate range, leakage of developer and scattering of toner can be reduced. Furthermore, the internal pressure of the developing device 26 tends to increase due to the suction airflow in the casing gap H described above, and if the internal pressure increases, toner will scatter from the gaps in the developing device 26. In contrast, in this embodiment, the opening 26k1 in which the filter 26t is installed is provided, so that the toner is collected and prevented from scattering to the outside while only allowing ventilation, thereby suppressing an increase in the internal pressure of the developing device 26. In other words, toner scattering due to an increase in the internal pressure of the developing device 26 is prevented.

[0030] Here, in this embodiment, filter 26t is formed so that the weight density per unit volume at one end side (lower in Figure 4, one end side in the air passage direction) is lower than the weight density per unit volume at the other end side (upper in Figure 4, the other end side in the air passage direction). That is, the weight density per unit volume of the filter 26t is not uniform, but there are low and high weight density portions in the ventilation direction (communication direction, discharge direction). In other words, the filter 26t has a gradient in weight density per unit volume.

[0031] More specifically, filter 26t in this embodiment is a single-layer structure formed so that the weight density per unit volume gradually increases in the direction of the arrow in FIG. 5 (particularly FIG. 5(B)) from one end side (the side inside the device) to the other end side (the side outside the device). Such a filter 26t is formed so that the weight density per unit volume gradually increases along the airflow direction (exhaust direction). Specifically, the filter 26t shown in FIG. 5 has a relatively loose and fluffy mesh at one end and becomes denser toward the other end. Therefore, the toner collecting power of the filter 26t in this embodiment gradually increases along the airflow direction. Filter 26t is used so that one end side (the lower side in FIG. 4(A)) is on the upstream side in the air passage direction, and the other end side is on the downstream side in the air passage direction (the upper side in FIG. 4(A)).

[0032] Here, in the developing device 26 of this embodiment, the opening 26k1 has an edge portion 26k10 (wall portion) formed extending in a direction from inside the device to outside the device (the communication direction, which is the vertical direction in Figures 2 and 4(A)). The filter 26t is fitted into the edge 26k10 (opening 26k1) so that one end side (the side with lower weight density) is located inside the device (the bottom side in FIG. 4(A)) and the other end side (the side with higher weight density) is located outside the device (the top side in FIG. 4(A)). Moreover, the filter 26t is placed in the opening 26k1 with its non-ventilation surface (a surface through which air is not expected to flow) in contact with the edge portion 26k10. 4(A) shows a two-dimensional view of the filter 26t being placed (fitted) in the opening 26k1 in contact with the edge 26k10. However, in reality, the filter 26t is placed in the opening 26k1 in a state where all four side surfaces are in contact with the substantially rectangular edge 26k10.

[0033] As shown in FIG. 4(B), in this embodiment, filter 26t is originally formed so that, when it is in a standalone state not installed in opening 26k1 (the state in FIG. 4(B) where no external force is acting), the weight density per unit volume at one end side in the air passage direction (lower side in FIG. 4(B)) is lower than the weight density per unit volume at the other end side in the air passage direction (upper side in FIG. 4(B)) (a weight density gradient is formed). Specifically, the length N of the filter 26t in the intersecting direction when it is in a standalone state is set to be larger than the opening width M (length in the intersecting direction) of the opening 26k1 (N>M). 4(A), filter 26t is placed in close contact with opening 26k1 while being compressed to fit the shape of opening 26k1. However, even when filter 26t is placed in opening 26k1, the gradient of weight density from one end to the other end is maintained.

[0034] Now, referring to Figures 4 and 5, in this embodiment, filter 26t has a ring-shaped adhesion portion 26u formed around the other end surface (the upper surface in Figures 4 and 5(B), the upper surface shown in Figure 5(A), which is the ventilation surface) that can be adhered to a stopper member 26r (pressing member) as a member to be adhered. Specifically, the attachment portion 26u is formed of double-sided tape or adhesive and is configured to be attached to the stopper member 26r without any gaps (without allowing air to pass through). The attachment portion 26u is provided in a rectangular ring shape on the outer edge of the upper surface (the ventilation surface on the side with a high weight density) of the filter 26t so as to surround a central rectangular area from all sides. Therefore, on the upper surface of the filter 26t, only the central rectangular area surrounded by the attachment portion 26u is substantially a surface through which air can pass (air can be exhausted).

[0035] Here, the stopper member 26r as the member to be attached is an air-impermeable member made of a metal material, a molded resin material or the like, and is a plate-like member having an opening on the inside so as not to impede the function (air permeability) of the filter 26t. The attachment portion 26u of the filter 26t is attached to the edge of the opening of the stopper member 26r.

[0036] The stopper member 26r (attached member) is detachably installed on the developing device 26 (filter holding device) so as to prevent the filter 26t from coming off the device through the opening 26k1. The filter 26t is configured to be detachable from the outside of the developing device 26 (outside the device). Specifically, when mounting the filter 26t, as shown in Fig. 4(B), the filter 26 is moved in the direction of the white arrow from above the developing device 26 (opening 26k1), and the filter 26t is fitted into the opening 26k1 as shown in Fig. 4(A). Then, in order to prevent the filter 26t from coming off upward, the stopper member 26r is fixed (screw-fastened) to the developing case 26k with a screw 90 so as to press the filter 26t from above. In this embodiment, a plate-shaped member having an opening on the inside is used as the stopper member 26r, but the stopper member 26r is not limited to this as long as it does not impair the function of the filter 26 and the filter 26t can be attached via the attachment portion 26u. For example, the stopper member 26r may have a coarse mesh formed in the opening on the inside. In order to prevent toner from scattering from a gap between the stopper member 26r and the developing case 26k, the stopper member 26r is preferably installed on the developing case 26k via a sealant made of polyurethane foam or the like.

[0037] In this manner, the filter 26t in this embodiment is provided with an adhesive portion 26u on the ventilation surface at the other end side (the side with higher weight density) in the ventilation direction, so that no gap is generated between the filter 26t and the stopper member 26r. This reduces the problem that the air (discharge target) in the developing device 26 leaks out together with the toner (collection target) from the side of the filter 26t (between the edge portion 26k10). This allows the function of the filter 26t described above to be fully exerted, and reduces the problem that the toner (collection target) scatters outside the developing device 26. In detail, the filter 26t has a low weight density per unit volume and has a portion with weak adhesion to the edge portion 26k10, so that the air is likely to leak out from that portion. That is, when a filter 126t as a comparative example shown in FIG. 6B, which does not have the adhesive portion 26u, is used, the toner in the device is discharged from the side of the filter 126t (where the adhesion is weak) together with the air through the gap between the stopper member 26r and the filter 126t to the outside of the device (moving in the direction of the black arrow). In contrast, in the present embodiment, as shown in Fig. 6(A), the gap between the stopper member 26r and the filter 26t is blocked by the adhesive portion 26u, and the path (path in the direction of the black arrow) along which the toner is discharged to the outside of the device together with the air is blocked. Therefore, the toner is collected by the filter 26t, and only the air is discharged to the outside of the device (direction of the white arrow). In this embodiment, the filter 26t is formed so that the weight density increases from the upstream side to the downstream side in the ventilation direction (communication direction) in order to facilitate the formation of an air flow from the inside to the outside of the developing device 26. This effectively prevents an increase in the internal pressure of the developing device 26, improves the overall toner collection ability of the filter 26t, and makes the filter 26t less likely to become clogged.

[0038] In addition, in order to solve the problems of the present invention, in the filter 26t of this embodiment, an adhesive part may be provided on the ventilation surface at one end side (low weight density side) in the ventilation direction, instead of the other end side (high weight density side), and the part may be attached to a member to be attached (for example, a part of the developing case 26k) so that no gaps are generated in that part. However, in that case, it is not possible to completely prevent air from flowing together with toner from the side surface at one end side (low weight density side) in the ventilation direction (it is not possible to completely prevent the flow in the direction of the black arrow in FIG. 6). In other words, it is important to provide an adhesive part on the ventilation surface at the other end side (high weight density side) in the ventilation direction, and attach the part to a member to be attached so that no gaps are generated in that part.

[0039] <Variation 1> As shown in FIG. 7, in the developing device 26 in the first modified example, the filter 26t is not a single-layer structure, but a two-layer structure in which a low-density portion 26t2 having a low weight density per unit volume is formed on one end side (the lower side in FIG. 7, the one end side in the air passage direction) and a high-density portion 26t1 having a high weight density per unit volume is formed on the other end side (the upper side in FIG. 7, the other end side in the air passage direction). That is, in the filter 26t, the low-density portion 26t2 on one end side is coarse and relatively fluffy, while the high-density portion 26t1 on the other end side is dense. Therefore, in the filter 26t in the first modification, the toner collecting power of the high-density portion 26t1 is higher than the toner collecting power of the low-density portion 26t2. The filter 26t in the first modification also has an annular attachment portion 26u that can be attached to a stopper member 26r (pressing member) as an attachment target member, around the ventilation surface on the other end side in the ventilation direction (the upper surface in FIG. 7, which is the upper surface of the high density portion 26t1). This can reduce the problem that air is discharged together with toner without passing through the filter 26t. 7A and 7B, the filter 26t in the first modification is integrated with the stopper member 26r (attached member) by adhering it to the adhering portion 26u. That is, the filter 26t and the stopper member 26r are unitized as one component, and the unitized filter 26t is attached to and detached from the developing device 26. This improves the ease of attachment and detachment of the filter 26t and the stopper member 26r, and also improves the positional accuracy of the filter 26t relative to the stopper member 26r.

[0040] <Variation 2> 8, in the developing device 26 in the second modification, the edge of the opening 26k1 is formed so that the opening area of ​​the opening 26k1 becomes smaller from the outside of the device to the inside of the device. Also in the second modification, an attachment portion 26u is formed on the outer edge of the upper surface (downstream side in the air flow direction) of the filter 26t and is attached to the stopper member 26r. In detail, the developing device 26 shown in FIG. 8(A) is formed such that the opening area of ​​the edge portion 26k10 becomes continuously smaller from the outside of the device to the inside of the device (from the top to the bottom of FIG. 8(A)). That is, edge 26k10 is inclined (an inclined surface is formed) away from the center of the opening from the upstream side in the discharge direction to the downstream side in the discharge direction with respect to the discharge direction (ventilation direction) in which air is discharged outside the device. By configuring the edge portion 26k10 in this manner, it is possible to compress the portion having a low weight density and being easily compressed at a high compression ratio, thereby improving the adhesion to the opening 26k1. In addition, it becomes easier to assemble the filter 26t from the outside of the developing device 26, and easier to remove the filter 26t from the developing device 26. Furthermore, the lower end of the inclination of the edge portion 26k10 functions as a restricting portion that prevents the filter 26t from falling into the developing device 26. Even in this configuration, it is possible to reduce the problem that the air inside the developing device 26 is discharged to the outside of the device together with the toner without passing through the filter 26t.

[0041] In contrast, the developing device 26 shown in FIG. 8(B) is formed so that the edge portion has an opening area that gradually decreases from the outside of the device to the inside of the device (from the top to the bottom in FIG. 8(B)). In detail, the opening 26k1 has a two-tier structure in which a first edge 26k11 with a large opening area is formed on the side outside the device (the upper side in Figure 8(B)), and a second edge 26k12 with a small opening area is formed on the side inside the device (the lower side in Figure 8(B)). Even in this configuration, it is possible to reduce the problem that the air in the developing device 26 is discharged together with the toner to the outside of the device without passing through the filter 26t. Also, even in the case where the edge portions 26k11, 26k12 are formed so that the opening area is gradually reduced, the operability of attaching and detaching the opening portion 26k1 from the outside of the device is improved, as in the case of Fig. 8(A), and the step of the edge portions 26k11, 26k12 makes it difficult for the filter 26t to fall off into the device.

[0042] <Modification 3> As shown in FIG. 9, the developing device 26 in the third modified example is formed with a restricting portion 26k15 that restricts the filter 26t from falling off from the opening 26k1 (edge ​​portion 26k10) into the device. Specifically, a limiting portion 26k15 that protrudes in a direction narrowing the opening is formed below the opening 26k1 (edge ​​portion 26k10) in the developing case 26k. The restricting portion 26k15 is formed so as to abut against one end side (a portion with low weight density, which is one end side in the air passage direction) of the filter 26t. Providing the limiting portion 26k15 in this manner can prevent the filter 26t placed in the opening 26k1 from falling into the developing device 26. In addition, it becomes easier to determine the vertical position of the filter 26t in the opening 26k1. Also in the third modification, an attachment portion 26u is formed on the outer edge of the upper surface (downstream side in the air flow direction) of the filter 26t and is attached to the stopper member 26r. This reduces the problem that the air in the developing device 26 is discharged to the outside of the device together with the toner without passing through the filter 26t.

[0043] As described above, filter 26t in this embodiment is formed so that the weight density per unit volume on one end side is lower than the weight density per unit volume on the other end side. Filter 26t has attachment portion 26u attached to stopper member 26r (attachment member) formed around the surface on the other end side. This can reduce the problem of air (discharge target) being discharged together with toner (collection target).

[0044] In the present embodiment, the developing device 26 is not a component of the process cartridge 20, but is a unit that can be attached to and detached from the image forming apparatus main body 1 alone. Alternatively, the developing device 26 can be one of the components of the process cartridge 20, and can be configured to be attached to and detached from the image forming apparatus main body 1 as a process cartridge. In such a case, the same effect as that of this embodiment can be obtained. In this application, a "process cartridge" is defined as a unit in which at least one of a charging device for charging an image carrier, a developing device for developing a latent image formed on the image carrier, and a cleaning device for cleaning the image carrier is integrated with an image carrier, and is configured to be detachable from the main body of an image forming apparatus.

[0045] In this embodiment, the present invention is applied to a developing device 26 in which two transport screws 26b1, 26b2 (transport members) are arranged side by side in the horizontal direction, and a doctor blade 26c is arranged below a developing roller 26a. However, the configuration of the developing device to which the present invention is applied is not limited to this, and the present invention can be applied to, for example, a developing device in which three or more transport members are arranged side by side in the horizontal direction, a developing device in which a plurality of transport members are arranged side by side in the vertical direction, or a developing device in which a doctor blade is arranged above a developing roller. In the present embodiment, the present invention is applied to the developing device 26 that uses a two-component developer made of toner and carrier. However, the present invention can also be applied to a developing device that uses a one-component developer made of only toner (including external additives, etc.). In such cases, substantially the same effects as those of this embodiment can be obtained.

[0046] In addition, in this embodiment, the present invention is applied to the developing device 26 as a filter holding device, but the filter holding device to which the present invention is applied is not limited to this, and can be applied to, for example, all devices that contain powder such as toner inside, such as toner container 70, waste toner collection container 80, cleaning device 23, intermediate transfer belt cleaning device 81, toner supply device, toner transport device, etc. In addition, in this embodiment, the present invention is applied to the developing device 26 as a filter holding device configured to collect toner as a collection target and discharge air as a discharge target outside the device, but the filter holding device (combination of a discharge target and a collection target) to which the present invention is applied is not limited to this. For example, the present invention can also be applied to the image forming device main body 1 as a filter holding device configured to collect ozone as a collection target and discharge air (air not containing ozone) as a discharge target outside the device. In the present embodiment, the attachment portion 26u of the filter 26t is attached to the stopper member 26r as the attachment target member. However, the attachment target member to which the attachment portion 26u of the filter 26t is attached is not limited thereto, and for example, the attachment portion 26u of the filter 26t may be directly attached to the development case 26k as the attachment target member. In such cases, substantially the same effects as those of this embodiment can be obtained.

[0047] It is clear that the present invention is not limited to the present embodiment, and that each embodiment may be appropriately modified within the scope of the technical concept of the present invention in addition to what is suggested in each embodiment. Furthermore, the number, position, shape, etc. of the components are not limited to the present embodiment, and may be any number, position, shape, etc. suitable for implementing the present invention.

[0048] In the present specification, the term "annular" is defined as a shape with a hole in the middle. Therefore, the term "annular" includes not only circular annular shapes, but also square annular shapes. [Explanation of symbols]

[0049] 1 Image forming apparatus (image forming apparatus main body), 20, 20Y, 20M, 20C, 20BK process cartridges, 21 photosensitive drum (image carrier), 26 Developing device (filter holding device), 26a developing roller (developer carrier), 26k developing case, 26k1 Openings (ventilation passages), 26k10 Edge (wall), 26k11, 26k12 edges, 26k15 Restriction section, 26t filter, 26t1 high density part, 26t2 low density part, 26u adhesive part, 26r Stopper part (part to be attached). [Prior art documents] [Patent documents]

[0050] [Patent Document 1] JP 2014-178347 A

Claims

1. a filter that is disposed in an opening that communicates between the inside of the device and the outside of the device and is formed so that the weight density per unit volume on one end side is lower than the weight density per unit volume on the other end side; the opening has an edge extending in a direction from inside the device to outside the device; The filter comprises: An attachment portion that can be attached to an attachment target member is formed around the periphery of the surface on the other end side, the one end is located inside the device and is on the upstream side in the air flow direction, and the other end is located outside the device and is on the downstream side in the air flow direction, and is fitted to the edge portion; A filter holding device, characterized in that the adhesion portion is adhered to the attachment member on the outside of the device.

2. 2. The filter holding device according to claim 1, wherein the attachment portion is formed of a double-sided tape or an adhesive.

3. 3. The filter holding device according to claim 1, which is a single-layer structure formed so that the weight density per unit volume gradually increases from the one end side to the other end side.

4. A filter holding device as described in claim 1 or claim 2, characterized in that it is a two-layer structure in which a low-density portion having a low weight density per unit volume is formed on the one end side and a high-density portion having a high weight density per unit volume is formed on the other end side.

5. The adherend member is an air-impermeable member, 5. The filter holding device according to claim 1, wherein the adherend is attached to the adhesion portion and is integrated with the adhesion portion.

6. 6. The filter holding device according to claim 1, wherein the adhesion portion is formed in a ring shape.

7. 7. The filter holding device according to claim 1, wherein the attachment member is detachably attached to the filter holding device.

8. The filter holding device according to any one of claims 1 to 7, further comprising a limiting portion for limiting the filter from falling out of the opening into the device.

9. The filter holding device according to claim 8, wherein the restricting portion is formed so that the one end side of the filter abuts against the restricting portion.

10. A developing device that contains toner and develops a latent image formed on a surface of an image carrier, A developing device comprising the filter holding device according to any one of claims 1 to 9.

11. A process cartridge that is detachably installed in a main body of an image forming apparatus, A process cartridge comprising the developing device according to claim 10 and the image carrier integrally formed therewith.

12. 12. An image forming apparatus comprising at least one of the holding device according to claim 1, the developing device according to claim 10, and the process cartridge according to claim 11.

Images