Developing device and image forming apparatus

Abstract

To prevent accumulation of cloud toner in an air channel in a saved space to stabilize the internal pressure of a developer storage unit.SOLUTION: A developing device comprises: a housing that can store developer therein; a cover member that closes an upper opening of the housing; a developer holding body that is supported by the housing and rotates while holding developer on its outer surface; a regulation member that is arranged facing the developer holding body and regulates the amount of developer on the outer surface; a first exhaust passage that is formed inclined toward the inside of the housing and exhausts air from the inside of the housing to the outside of the housing; and a second exhaust passage that is connected with the first exhaust passage and is connected from the first exhaust passage to a filter member provided on the cover member and inhibiting the passage of developer and permitting the passage of air.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a developing device and an image forming apparatus.

Background Art

[0002] An image forming apparatus having an image carrier that carries a latent image on its surface and a developing device that develops the latent image, the developing device including a developer storage unit that stores a developer therein, a developer carrier that carries the developer on the surface in the developer storage unit, a developer storage unit opening provided in the developer storage unit to expose a part of the surface of the developer carrier outside the developer storage unit, and a developer carrier driving unit that moves the surface of the developer carrier between the inside and the outside of the developer storage unit, and the developing device being configured to be movable between a developing position where the developer carrier faces the image carrier and a non-developing position other than the developing position, and an image forming apparatus provided with an internal pressure increase preventing unit for preventing an increase in the internal pressure in the developer storage unit is known (Patent Document 1).

[0003] A developing device including a developer carrier that carries a developer on its surface and moves on the surface to supply the developer to a latent image on the surface of a latent image carrier facing the latent image carrier, a developer conveying member that imparts a conveying force by rotating to the developer in a developer storage unit that stores the developer to be supplied to the developer carrier, a pressure release opening that discharges the gas in the developer storage unit to the outside of the apparatus and suppresses an increase in the air pressure in the developer storage unit, and a filter member provided in the pressure release opening that suppresses the discharge of the developer from the pressure release opening, and a developing device including a developer movement path shielding member that blocks a movement path of the developer that is bounced up when the developer conveying member rotates toward the filter member is also known (Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention suppresses the cloud toner deposition in the air flow path in a space-saving manner and stabilizes the internal pressure in the developer housing.

Means for Solving the Problems

[0006] To solve the above problems, the developing device according to claim 1 includes a housing capable of accommodating a developer composed of toner and a carrier therein, a cover member that closes the upper opening of the housing, a developer holder supported by the housing, which holds the developer on its outer surface and rotates, a regulating member disposed above the developer holder and facing the developer holder, which regulates the amount of developer on the outer surface, on the One part upstream side in the rotation direction of the developer holder, inclined toward the accommodation portion of the developer in the housing in the housing, extends to form a gap with the inner surface of the cover member a first discharge path formed for discharging air from the inside of the housing to the outside of the housing, a second discharge path connected to the first discharge path and connected to a filter member provided in the cover member that blocks the passage of the developer and allows the passage of the air, characterized in that.

[0007] The invention according to claim 2 is the developing device according to claim 1, wherein the regulating member includes a regulating portion facing the developer holder with a predetermined gap, a mounting portion extending intersecting the regulating portion, and a guiding portion extending intersecting the mounting portion and inclined toward the inside of the housing, and the first discharge path is formed with a gap between the upper surface of the guiding portion and the inner surface of the cover member facing each other. characterized in that.

[0008] The invention according to claim 3 is the developing device according to claim 2, wherein the first discharge path is inclined at an angle exceeding the angle of repose of the toner. This is the gist of the invention.

[0009] The invention according to claim 4 is the developing device according to claim 3, wherein the upper surface of the guide portion is subjected to a surface treatment for suppressing adhesion of the toner. This is the gist of the invention.

[0010] The invention according to claim 5 is the developing device according to any one of claims 2 to 4, wherein the second discharge path is formed to be inclined along the first discharge path with a gap between the outer surface of the cover member and the inner surface of the filter member facing each other. This is the gist of the invention.

[0011] The invention according to claim 6 is the developing device according to claim 5, wherein the second discharge path is inclined at an angle exceeding the angle of repose of the toner. This is the gist of the invention.

[0012] The invention according to claim 7 is the developing device according to claim 5 or 6, wherein the second discharge path is formed such that the gap widens along the inclination. This is the gist of the invention.

[0013] The invention according to claim 8 is the developing device according to any one of claims 5 to 7, wherein the outer surface of the cover member is subjected to a surface treatment for suppressing adhesion of the toner. This is the gist of the invention.

[0014] The invention according to claim 9 is the developing device according to any one of claims 2 to 8, wherein the filter member is disposed to be inclined so as to block the second discharge path. This is the gist of the invention.

[0015] The invention according to claim 10 is the developing device according to claim 9, wherein the filter member is adhered to the cover member with a double-sided tape. This is the gist.

[0016] The invention according to claim 11 is the developing device according to any one of claims 2 to 10, wherein a first seal member for blocking the inflow of the air from the first discharge path is disposed between the mounting portion of the restricting member and the cover member. This is the gist.

[0017] The invention according to claim 12 is the developing device according to claim 11, wherein a second seal member for blocking the air flow generated by the rotation of the developer holding member is disposed between the mounting portion of the restricting member and the cover member, and an opening communicating with the outside is provided in the cover member in a region surrounded by the first seal member and the second seal member. This is the gist.

[0018] The invention according to claim 13 is the developing device according to any one of claims 1 to 12, wherein the housing includes a first circulation path for transporting the received developer while stirring it, and a second circulation path for supplying the stirred developer to the developer holding member while transporting it, and the first discharge path is connected to the second circulation path. This is the gist.

[0019] The invention according to claim 14 is the developing device according to claim 13, wherein the first discharge path is formed on the terminal side in the transport direction of the second circulation path. This is the gist.

[0020] In order to solve the above problems, the image forming apparatus according to claim 15 includes an image carrier on which an electrostatic latent image is formed on the surface, and The developing device according to any one of claims 1 to 14, which supplies the toner to the electrostatic latent image formed on the surface of the image holding body to develop the electrostatic latent image, and is characterized in that.

Advantages of the Invention

[0021] According to the inventions described in claims 1 and 15, it is possible to suppress the deposition of cloud toner in the air flow path in a space-saving manner and stabilize the internal pressure in the developer housing portion.

[0022] According to the invention described in claim 2, it is possible to suppress the temperature rise of the regulating member.

[0023] According to the inventions described in claims 3 and 4, it is possible to suppress the deposition of cloud toner in the air flow path.

[0024] According to the invention described in claim 5, it is possible to efficiently capture cloud toner by widening the surface of the filter in contact with air and suppress the deposition of cloud toner.

[0025] According to the invention described in claim 6, it is possible to suppress the deposition of cloud toner in the air flow path.

[0026] According to the invention described in claim 7, it is possible to store cloud toner.

[0027] According to the invention described in claim 8, it is possible to suppress the deposition of cloud toner in the air flow path.

[0028] According to the invention described in claim 9, it is possible to achieve space saving of the developing device.

[0029] According to the invention described in claim 10, it is possible to achieve space saving of the developing device and facilitate assembly.

[0030] According to the inventions described in claims 11 and 12, it is possible to suppress the suction and discharge of the air containing the cloud toner from the first discharge path.

[0031] According to the inventions described in claims 13 and 14, it is possible to reduce the amount of the cloud toner to be discharged.

Brief Description of the Drawings

[0032]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0033] Next, with reference to the drawings, embodiments and specific examples will be given below to explain the present invention in more detail, but the present invention is not limited to these embodiments and specific examples. Also, in the following description using the drawings, it should be noted that the drawings are schematic, and the ratios of each dimension, etc. are different from the actual ones, and the illustrations other than the members necessary for the explanation are appropriately omitted for ease of understanding. In addition, for ease of understanding the following description, in the drawings, the front-rear direction is the X-axis direction, the left-right direction is the Y-axis direction, and the up-down direction is the Z-axis direction.

[0034] (1) Overall Configuration and Operation of the Image Forming Apparatus (1.1) Overall Configuration of the Image Forming Apparatus FIG. 1 is a cross-sectional schematic view showing an example of the schematic configuration of an image forming apparatus 1 according to the present embodiment. The image forming apparatus 1 includes an image forming unit 10, a paper feeding device 20 attached to one end of the image forming unit 10, a paper discharging unit 30 provided at the other end of the image forming unit 10 where the printed paper is discharged, and an image processing unit 40 (not shown) that generates image information from the print information transmitted from a host device.

[0035] The image forming unit 10 includes a system control device 11 (not shown), an exposure device 12, a photoreceptor unit 13, a developing device 14, a transfer device 15, paper conveying devices 16a, 16b, 16c, a fixing device 17, and a driving device 18 (not shown), and forms the image information received from the image processing unit 40 as a toner image on the paper P fed from the paper feeding device 20.

[0036] The paper feeding device 20 supplies paper to the image forming unit 10. That is, it includes a plurality of paper stacking units that accommodate papers of different types (for example, material, thickness, paper size, paper texture), and is configured to supply the paper P fed from any one of these plurality of paper stacking units to the image forming unit 10.

[0037] The paper discharge unit 30 discharges the paper on which image output has been performed by the image forming unit 10. For this purpose, the paper discharge unit 30 includes a paper discharge storage unit into which the paper after image output is discharged. Note that the paper discharge unit 30 may have a function of performing post-processing such as cutting or stapling (stitching with needles) on the paper bundle output from the image forming unit 10.

[0038] (1.2) Configuration and Operation of Image Forming Unit In the image forming apparatus 1 having such a configuration, in accordance with the timing of image formation, among the paper feeding devices 20, the paper fed out from the paper stacking unit designated for each sheet in the print job is fed into the image forming unit 10.

[0039] The photoreceptor unit 13 includes a photoreceptor drum 31 as an image holding member that is provided in parallel below the exposure device 12 and is rotationally driven. Along the rotation direction of the photoreceptor drum 31, a charging roll 32, an exposure device 12, a developing device 14, a primary transfer roll 52, and a cleaning blade 34 are arranged.

[0040] The developing device 14 has a developing housing 41 in which a developer is accommodated. In the developing housing 41, a developing roll 42 disposed to face the photoreceptor drum 31 is provided, and a regulating member 45 (see FIG. 2) for regulating the layer thickness of the developer is disposed in the vicinity of the developing roll 42. Each developing device 14 is configured substantially the same except for the developer accommodated in the developing housing 41, and each forms a toner image of yellow (Y), magenta (M), cyan (C), and black (K).

[0041] Above the developing device 14, an exchangeable toner cartridge T for accommodating a developer (toner including a carrier) and a developer supply device 100 for supplying the developer from each toner cartridge T to the developing device 14 are arranged. In the present embodiment, the toner cartridges Ty, Tm, Tc for yellow (Y), magenta (M), and cyan (C) and two toner cartridges Tk for black (K) are detachable.

[0042] The surface of the rotating photoreceptor drum 31 is charged by the charging roll 32, and an electrostatic latent image is formed by the latent image forming light emitted from the exposure device 12. The electrostatic latent image formed on the photoreceptor drum 31 is developed into a toner image by the developing roll 42.

[0043] The transfer device 15 includes an intermediate transfer belt 51 on which the toner images of each color formed on the photoreceptor drum 31 of each photoreceptor unit 13 are multi-transferred, a primary transfer roll 52 that sequentially transfers (primary transfer) the toner images of each color formed in each photoreceptor unit 13 to the intermediate transfer belt 51, and a secondary transfer roll 53 that collectively transfers (secondary transfer) the toner images of each color superimposed and transferred on the intermediate transfer belt 51 to the paper P which is a recording medium.

[0044] The toner images of each color formed on the photoreceptor drum 31 of each photoreceptor unit 13 are sequentially electrostatically transferred (primary transfer) onto the intermediate transfer belt 51 by the primary transfer roll 52 to which a predetermined transfer voltage is applied from a power supply device (not shown) controlled by the system control device 11, and a superimposed toner image in which the toners of each color are superimposed is formed.

[0045] The superimposed toner image on the intermediate transfer belt 51 is conveyed to a secondary transfer section TR where the secondary transfer roll 53 is press-contacted with the backup roll 65 via the intermediate transfer belt 51 as the intermediate transfer belt 51 moves. When the superimposed toner image is conveyed to the secondary transfer section TR, paper is supplied from the paper feeding device 20 to the secondary transfer section TR at that timing. Then, a predetermined secondary transfer voltage is applied from a power supply device controlled by the system control device 11 to the backup roll 65 facing the secondary transfer roll 53 via the intermediate transfer belt 51, and the multi-toner image on the intermediate transfer belt 51 is collectively transferred to the paper.

[0046] The residual toner on the surface of the photoreceptor drum 31 is removed by the cleaning blade 34 and collected in a waste toner container (not shown). The surface of the photoreceptor drum 31 is recharged by the charging roll 32.

[0047] The fixing device 17 includes an endless fixing belt 17a that rotates in one direction and a pressure roll 17b that is in contact with the circumferential surface of the fixing belt 17a and rotates in one direction. A nip portion (fixing region) is formed by the pressure contact region between the fixing belt 17a and the pressure roll 17b. The sheet on which the toner image has been transferred in the transfer device 15 is conveyed to the fixing device 17 via the sheet conveyance device 16a in a state where the toner image is unfixed. The sheet conveyed to the fixing device 17 has the toner image fixed by the action of pressure bonding and heating by the pair of fixing belt 17a and pressure roll 17b.

[0048] The sheet on which fixing has been completed is sent to the paper discharge unit 30 via the sheet conveyance device 16b. In addition, when performing image output on both sides of the sheet, the front and back of the sheet are reversed by the sheet conveyance device 16c and sent again to the secondary transfer unit TR in the image forming unit 10. Then, after the transfer of the toner image and the fixing of the transferred image are performed, it will be sent to the paper discharge unit 30. The sheet sent to the paper discharge unit 30 is discharged to the paper discharge storage unit after undergoing post-processing such as cutting and stapling (stitching) as necessary.

[0049] (2) Configuration and operation of the main part FIG. 2 is a schematic cross-sectional view showing the main part of the image forming unit 10 including the photosensitive member unit 13 and the developing device 14. FIG. 3 is a schematic cross-sectional view developed in a plan view along the line A - B - C for explaining the conveyance of the developer in the developing device 14. FIG. 4 is a schematic cross-sectional view showing the configuration of the developing device 14. Hereinafter, the configuration and operation of the main part of the image forming unit 10 will be described with reference to the drawings. (2.1) Configuration of the photosensitive member unit In the photosensitive member unit 13, the photosensitive drum 31 is rotatably supported by the unit housing 35. Inside the unit housing 35, a charging roll 32, a cleaning roll 33, a cleaning blade 34, and a conveying auger 36 for conveying the toner removed by the cleaning blade 34 to a waste toner collection container (not shown) are arranged.

[0050] (2.2) Configuration and operation of the developing device As shown in FIG. 2, in the developing device 14, a developing roll 42 is rotatably supported by a developing housing 41, and an agitation auger 43A, a supply auger 43B, and a regulating member 45 are arranged in the developing housing 41. The space around the agitation auger 43A and the supply auger 43B in the developing housing 41 is filled with a developer and is closed off by a cover member 44.

[0051] The developing roll 42 is disposed opposite to the outer peripheral surface of the photosensitive drum 31 through an opening 41a formed in the developing housing 41. The developing roll 42 is formed in a columnar shape and is arranged so as to extend along the direction from the front side to the back side of the image forming apparatus 1 (shown in FIG. 4). Further, the developing roll 42 includes a cylindrical developing sleeve 42A rotatably supported with respect to the developing housing 41, and a magnet 42B as a columnar magnet member provided in the internal space of the developing sleeve 42A and fixed with respect to the developing housing 41. The developing sleeve 42A is configured such that the developer is held on the outer peripheral surface by the magnetic force of the magnet 42B, and the developer is conveyed and supplied to the electrostatic latent image on the photosensitive drum 31 by the rotation of the developing sleeve 42A (indicated by arrow B in FIG. 2).

[0052] The developing device 14 is also provided with an agitation auger 43A and a supply auger 43B for conveying the developer while agitating it. FIG. 3 is a schematic cross-sectional view developed in the horizontal direction along line A - B - C to explain the conveyance (movement) of the developer in the developing device 14. In the developing housing 41, a partition wall 41b is erected between the agitation auger 43A and the supply auger 43B, and the developing housing 41 is partitioned into two developer storage portions 41A and 41B. Openings 41C and 41D are formed at both longitudinal ends of the partition wall 41b, respectively.

[0053] The agitation auger 43A and the supply auger 43B receive a rotational force from a drive source (not shown) and rotate along the inner walls of the developer storage portions 41A and 41B, thereby conveying the developer in a predetermined direction within the developer storage portions 41A and 41B. Specifically, the agitating auger 43A conveys the developer in the developer housing 41A as the first circulation path in the direction of the arrow (-Y) (front side) while agitating it, and the supply auger 43B conveys the developer in the developer housing 41B as the second circulation path in the direction of the arrow (Y) (rear side) while agitating it. The developer conveyed in the direction of the arrow (-Y) moves from the opening 41C to the developer housing 41B, and the developer conveyed in the direction of the arrow (Y) moves from the opening 41D to the developer housing 41A. As a result, the developer in the developing housing 41 circulates and moves while being agitated by the two agitating augers 43A and the supply auger 43B. Due to such agitation of the developer, the toner in the developer becomes charged.

[0054] As shown in FIG. 4, a regulating member 45 is provided above the developing roll 42 in the developing device 14. The regulating member 45 is arranged with a predetermined gap from the developing roll 42, restricts the movement of a part of the developer held on the surface of the developing roll 42, and makes the thickness of the developer held on the surface of the developing roll 42 a predetermined thickness.

[0055] Next, the magnet 42B disposed inside the developing sleeve 42A will be described. The magnet 42B is provided with five magnetic poles N1 to N3 (N poles) and S1 to S2 (S poles) along the circumferential direction of the magnet 42B. The magnetic pole N2 (pickup pole) attracts the developer conveyed by the supply auger 43B and adheres it to the surface of the developing sleeve 42A. The magnetic pole S2 (trimming pole) faces the regulating member 45 and holds the developer trimmed to a predetermined layer thickness by the regulating member 45. The magnetic poles N3 and N1 have the role of conveying poles and move the developer on the developing sleeve 42A to the downstream side in the rotational direction of the developing sleeve 42A.

[0056] The magnetic pole S1 is disposed opposite to the photoreceptor drum 31 and is adapted to hold the developer conveyed from the magnetic pole N1 by the rotation of the developing sleeve 42A. A developing bias voltage is applied between the developing sleeve 42A and the photoreceptor drum 31 to form an electric field. Toner in the developer moves to the photoreceptor drum 31, and the carrier in the developer is held by the magnetic pole S1, suppressing its adhesion to the photoreceptor drum 31. The pickup pole forms a repulsive magnetic field together with the adjacent like magnetic poles N2 and N3, and detaches the developer on the developing sleeve 42A, where toner has been consumed during development, from the developing sleeve 42A.

[0057] (2.3) Configuration and operation of the discharge path FIG. 5 is an enlarged view of the portion indicated by reference numeral A in FIG. 4 showing the configuration of the discharge path, and FIG. 6 is a schematic cross-sectional view schematically showing the air flow and the movement of cloud toner ct in the developing device 14. Note that FIG. 5(a) is mainly labeled with reference numerals related to the first discharge path 46, and FIG. 5(b) is mainly labeled with reference numerals related to the second discharge path 47 to show the configuration of the discharge path.

[0058] The developing device 14 is provided with an air discharge path in the cover member 44 for discharging the air inside the developing housing 41 to the outside of the developing housing 41. A filter member 48 is provided at a portion where the discharge path is connected to the outside, and collects cloud toner ct contained in the air flowing through the discharge path and discharged.

[0059] In the present embodiment, the discharge path is formed to be inclined toward the inside of the developing housing 41, and includes a first discharge path 46 that discharges air from the inside of the developing housing 41 to the outside of the developing housing 41, and a second discharge path 47 that is connected to the first discharge path 46 and leads from the first discharge path 46 to the filter member 48 provided in the cover member 44 (see FIG. 4).

[0060] The first discharge path 46 is formed by disposing a part of the regulating member 45 and the inner wall surface 44a of the cover member 44 to face each other with a gap therebetween. As shown in Fig. 5(a), the regulating member 45 includes a regulating portion 45A facing the developing roll 42 with a predetermined gap, a mounting portion 45B extending intersecting the regulating member 45, and a guiding portion 45C extending obliquely toward the inside of the developing housing 41 intersecting the mounting portion 45B. It is formed as a gap G between the upper surface 45Ca of the guiding portion 45C and the inner wall surface 44a of the cover member 44 closing the upper opening of the developing housing 41.

[0061] The first discharge path 46 is formed to be inclined toward the developer storage portion 41B in which the supply auger 43B of the developing housing 41 is disposed, and the air inlet portion 46a is positioned above the developer storage portion 41B. In the developing device 14, since the developer supplied from the toner cartridge T via the developer supply device 100 is agitated in the developer storage portion 41A and then conveyed to the developer storage portion 41B and circulated, the cloud toner in the developer storage portion 41B is less than that in the developer storage portion 41A. Therefore, in the present embodiment, the inlet portion 46a of the first discharge path 46 is arranged to face the inside of the developer storage portion 41B, so that the cloud toner ct contained in the air discharged from the first discharge path 46 is reduced.

[0062] Further, the first discharge path 46 is arranged to be inclined so as to form a downward slope at an angle Θ (shown in Fig. 5) exceeding the angle of repose of the toner contained in the developer. Note that the angle of repose of the toner varies depending on the type of developer and the usage environment such as temperature and humidity. As a result, as shown in Fig. 6, even if cloud toner ct adheres to the upper surface 45Ca of the guiding portion 45C of the regulating member 45, the toner riding on the adhered toner will slide off (see arrow R2 in Fig. 6), and the deposition of toner on the upper surface 45Ca of the guiding portion 45C can be suppressed.

[0063] The upper surface 45Ca of the guide portion 45C is preferably subjected to a surface treatment for suppressing toner adhesion. Examples of the surface treatment include frame treatment, corona treatment, plasma treatment, polishing treatment, roughening treatment, active energy ray irradiation treatment, ozone treatment, surfactant treatment, and silane coupling treatment. A plurality of these may be combined. Further, a fluororesin tape or the like may be attached to the upper surface 45Ca. Thereby, deposition of toner on the upper surface 45Ca of the guide portion 45C is suppressed.

[0064] The discharge port 46b on the downstream side in the air flow direction of the first discharge path 46 (see arrow R0 in FIG. 6) is connected to the second discharge path 47. As shown in FIG. 5(b), the second discharge path 47 is formed by the outer surface 44b of the cover member 44 and the inner surface 48a of the filter member 48 facing each other with a gap and inclined along the first discharge path 46. That is, similar to the first discharge path 46, it is inclined so as to form a downward slope at an angle Θ (shown in FIG. 5) exceeding the angle of repose of the toner contained in the developer. Thereby, deposition of toner on the outer surface 44b of the cover member 44 can be suppressed. Further, the outer surface 44b of the cover member 44 constituting the second discharge path 47 is preferably subjected to a surface treatment for suppressing toner adhesion. Examples of the surface treatment include surfactant treatment and attachment of a fluororesin-based tape. Thereby, deposition of toner on the upper surface 45Ca of the guide portion 45C is suppressed.

[0065] As shown in FIG. 5(b), the second discharge path 47 is formed such that the gap becomes wider along the inclination, and a pocket-shaped space S is formed at the lower end of the inclination. Thereby, the cloud toner ct sliding on the outer surface 44b of the cover member 44 can be stored. Note that the space S is sized such that the amount of stored toner does not become full during the replacement interval of the developing device 14.

[0066] The second discharge path 47 has an air inlet 47a connected to the discharge port 46b of the first discharge path 46, and the discharge port 47b faces a filter member 48 provided on the cover member 44 that blocks the passage of the developer and allows the passage of air. As a result, the air inside the developing device 14 flows from the developer housing portion 41B into the first discharge path 46 and then toward the second discharge path 47 as shown in FIG. 6 (see arrow R0 in FIG. 6), passes through the filter member 48, and is discharged to the outside of the developing device 14 (see arrow R1 in FIG. 6).

[0067] The filter member 48 is directly attached to the upper surface 44a of the cover member 44 with a double-sided tape (not shown) so as to block the discharge port 47b of the second discharge path 47 at the upper part of the cover member 44. Thereby, while reducing the space occupied by the developing device 14, the assembly can be facilitated. The material of the filter member 48 is not particularly limited, and polyolefin (such as PE, PP, etc.), polyamide, polyester (such as PET, etc.), aromatic polyamide, or a composite material thereof can be used. As an example, by using a porous material with a collection efficiency of 25% (particle diameter 0.3 to 0.5 μm) and a pressure loss of about 3 Pa at 10 cm / sec, it is possible to suppress the pressure increase in the developing device 14 by allowing air to pass through while blocking the passage of the cloud toner ct generated in the developing housing 41.

[0068] FIG. 8 schematically shows the air flow and the movement of the cloud toner ct in a comparative example developing device 14A in which no opening connecting to the outside is provided in the cover member. As shown in FIG. 8, in the developing device 14A, due to the rotation of the developing roll 42, a strong rotational air flow R is generated around the developing roll 42. Due to this rotational air flow R, a negative pressure may be generated in the gap between the regulating member 45 above the developing roll 42 and the cover member 44, and there is a risk that the air flowing through the first discharge path 46 may flow in (see arrow f in the figure).

[0069] In the developing device 14 according to the present embodiment, as shown in FIG. 5, a first seal member 49A that blocks the inflow of air from the first discharge path 46 is disposed between the mounting portion 45B of the regulating member 45 and the cover member 44. The first seal member 49A is a foamed sponge. Thereby, the inflow of air from within the first discharge path 46 is suppressed.

[0070] Also, as shown in FIG. 5, a second seal member 49B that blocks the air flow associated with the rotational airflow R generated by the rotation of the developing roll 42 is disposed between the mounting portion 45B of the regulating member 45 and the cover member 44, and an opening 44c that connects to the outside is provided in the cover member 44 in a region surrounded by the first seal member 49A and the second seal member 49B. A plurality of openings 44c are provided in the axial direction of the developing roll 42.

[0071] In this way, after closing the space between the mounting portion 45B of the regulating member 45 and the cover member 44 with the first seal member 49A, an opening 44c that connects to the outside is provided in the cover member 44 to open to the atmosphere (see arrow F in FIG. 6), thereby suppressing the suction and discharge of air containing the cloud toner ct from the first discharge path 46.

[0072] FIG. 7 schematically shows, in broken lines, the arrangement positions of the first discharge path 46 and the opening 44c in the developing device 14. As shown in FIG. 7, the first discharge path 46 is connected to the inside of the developer storage portion 41B as a second circulation path in which the supply auger 43B conveys the developer toward the back side (in the direction of arrow (Y)) while stirring the developer, and is formed at the end side (back side) in the conveyance direction of the developer storage portion 41B as the second circulation path. That is, air is discharged from a region where less cloud toner ct is generated within the developing device 14. Thereby, the amount of the discharged cloud toner ct can be reduced. In addition, as shown in FIG. 7, the above-described opening 44c is provided at two locations on the front side and the back side above the developing roll 42. Thereby, the generation of negative pressure due to the rotation of the developing roll 42 is suppressed over the axial direction of the developing roll 42.

[0073] In this embodiment, the case where the regulating member 45 is disposed above the developing roll 42 has been described as an example. However, the regulating member 45 may be disposed below the developing roll 42. In that case, a part of the regulating member 45 is not used for forming the first discharge path 46, and a plate member (not shown) having a gap and facing the inner surface of the cover member 44 can be disposed to form it.

Explanation of Reference Numerals

[0074] 1 ··· Image forming apparatus 10 ··· Image forming section 13 ··· Photoconductor unit 31 ··· Photoconductor drum 14, 14A ··· Developing device 41 ··· Developing housing, 42 ··· Developing roll, 43A ··· Agitating auger, 43B ··· Supply auger, 44 ··· Cover member, 45 ··· Regulating member, 46 ··· First discharge path, 47 ··· Second discharge path, 48 ··· Filter member 20 ··· Paper feeding device 30 ··· Paper discharging section

Claims

1. A housing capable of accommodating a developer composed of toner and a carrier therein, a cover member closing an upper opening of the housing, a developer holding member supported by the housing and rotating while holding the developer on an outer surface thereof, a regulating member disposed to face the developer holding member above the developer holding member and regulating an amount of the developer on the outer surface, a first discharge path formed as a gap between an inner surface of the cover member by a part of the regulating member extending obliquely toward an accommodating portion of the developer in the housing on an upstream side in a rotation direction of the developer holding member, and discharging air from inside the housing to outside the housing, a second discharge path connected to the first discharge path and connected to a filter member provided in the cover member that blocks passage of the developer and allows passage of the air, a developing device characterized by the above.

2. The regulating member includes a regulating portion facing the developer holding member with a predetermined gap, an attachment portion extending intersecting with the regulating portion, and a guiding portion extending obliquely toward the inside of the housing intersecting with the attachment portion, and the first discharge path is formed by the upper surface of the guiding portion and the inner surface of the cover member facing each other with a gap. The developing device according to claim 1, characterized by the above.

3. The first discharge path is inclined at an angle exceeding an angle of repose of the toner. The developing device according to claim 2, characterized by the above.

4. The upper surface of the guiding portion is subjected to a surface treatment for suppressing adhesion of the toner. The developing device according to claim 3, characterized by the above.

5. The second discharge path is formed by the outer surface of the cover member and the inner surface of the filter member facing each other with a gap and inclined along the first discharge path. The developing device according to any one of claims 2 to 4, characterized by the above.

6. The second discharge path is inclined at an angle exceeding an angle of repose of the toner. The developing device according to claim 5, characterized by the above.

7. The second discharge path is formed such that the gap becomes wider along the inclination. The developing device according to claim 5 or 6, characterized by the above.

8. The outer surface of the cover member is subjected to a surface treatment for suppressing adhesion of the toner. The developing device according to any one of claims 5 to 7, characterized by the above.

9. The filter member is disposed obliquely so as to block the second discharge path. The developing device according to any one of claims 2 to 8, characterized in that.

10. The filter member is adhered to the cover member with a double-sided tape. The developing device according to claim 9, characterized in that.

11. A first seal member for blocking the inflow of the air from the first discharge path is disposed between the mounting portion of the restricting member and the cover member. The developing device according to any one of claims 2 to 10, characterized in that.

12. A second seal member for blocking the air flow generated by the rotation of the developer holding member is disposed between the mounting portion of the restricting member and the cover member, and an opening connected to the outside is provided in the cover member in a region surrounded by the first seal member and the second seal member. The developing device according to claim 11, characterized in that.

13. The housing includes a first circulation path for conveying the received developer while stirring it, and a second circulation path for supplying the stirred developer to the developer holding member while conveying it, and the first discharge path is connected to the second circulation path. The developing device according to any one of claims 1 to 12, characterized in that.

14. The first discharge path is formed on the terminal side in the conveying direction of the second circulation path. The developing device according to claim 13, characterized in that.

15. An image carrier on which an electrostatic latent image is formed on the surface. The developing device according to any one of claims 1 to 14, which supplies the toner to the electrostatic latent image formed on the surface of the image carrier to develop the electrostatic latent image, and an image forming apparatus. Characterized by that.

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