Developing device

Abstract

To positively return toner excessively put on a developing roller into a housing.SOLUTION: A developing device includes: a housing; a developing roller 20 extending in an axial direction; a lower film 60 that extends in the axial direction and contacts an outer peripheral surface of the developing roller 20; and a side seal 70 that contacts one end portion in the axial direction of the outer peripheral surface of the developing roller 20. The side seal 70 has an upstream seal 72 that overlaps one end portion in the axial direction of the lower film 60. The upstream seal 72 has a plurality of upstream convex portions 72A extending in a direction inclined so as to be positioned inside in the axial direction as it goes downstream in a moving direction on a surface contacting the outer peripheral surface of the developing roller 20. The lower film 60 has an inclined portion Eg inclined so as to be positioned inside in the axial direction as it goes downstream in the moving direction at an edge overlapping with the upstream seal 72. An inclination angle θ1 with respect to the moving direction of the upstream convex portion 72A is larger than an inclination angle θ2 with respect to the moving direction of the inclined portion Eg.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a developing device having a developing roller. [Background technology]

[0002] A conventional developing device is known that includes a housing having a toner supply port, a side seal adjacent to the supply port in the axial direction of the developing roller, and a lower film extending in the axial direction, the axial end of which overlaps with the side seal (see Patent Document 1). In this technology, the surface of the side seal is made up of multiple bristles. The multiple bristles form multiple protrusions that extend in an inclined direction so as to be positioned inward in the axial direction as they move downstream in the direction of movement of the outer circumferential surface of the developing roller.

[0003] The edge of the lower film that overlaps with the side seal has an inclined portion that inclines toward the axially inner side as it moves downstream in the moving direction. The inclination angle of the protrusion with respect to the moving direction is smaller than the inclination angle of the inclined portion with respect to the moving direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-91958 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the angle of inclination of the convex portion is smaller than the angle of inclination of the inclined portion, there is a problem in that the convex portion and the inclined portion make it difficult to return toner that has accumulated in excess on the developing roller into the housing.

[0006] Therefore, an object of the present invention is to actively return the toner that has accumulated in excess on the developing roller into the housing. [Means for solving the problem]

[0007] In order to solve the above problem, the developing device according to the present invention includes a housing, a developing roller, a lower film, and a side seal. The housing is capable of containing toner. The developer roller extends axially and is rotatable relative to the housing. The lower film extends in the axial direction and contacts the outer circumferential surface of the developing roller. The side seal contacts one end of the outer peripheral surface of the developing roller in the axial direction. The side seal includes an upstream seal that overlaps one end of the lower film in the axial direction, and a downstream seal that is located downstream of the upstream seal in the movement direction of the outer peripheral surface of the developing roller. The upstream seal has, on its surface that contacts the outer peripheral surface of the developing roller, a plurality of upstream protrusions that extend in an inclined direction so as to be positioned inward in the axial direction as they move downstream in the movement direction. The lower film has an inclined portion at an edge that overlaps the upstream seal, the inclined portion inclining toward the inside in the axial direction as it goes downstream in the moving direction. The inclination angle of the upstream convex portion relative to the movement direction is larger than the inclination angle of the inclined portion relative to the movement direction.

[0008] According to this configuration, the inclination angle of the upstream convex portion is greater than the inclination angle of the inclined portion, so that excess toner on the developing roller can be actively returned into the housing by the upstream convex portion and the inclined portion.

[0009] The upstream seal may be made of a fibrous member, and a tip of the fibrous member may protrude beyond the lower film.

[0010] With this configuration, the fibrous member of the upstream seal rides up onto the inclined portion and forms a wall along the inclined portion, which allows excess toner on the developing roller to be returned to the housing.

[0011] In addition, the downstream seal may have a plurality of downstream convex portions extending in an inclined direction so as to be positioned more inward in the axial direction as it moves downstream in the movement direction, and the inclination angle of the downstream convex portions with respect to the movement direction may be smaller than the inclination angle of the inclined portions with respect to the movement direction.

[0012] According to this configuration, the downstream-side convex portion with a small inclination angle can prevent toner from leaking outward in the axial direction.

[0013] The inclined portion may entirely overlap the upstream seal.

[0014] According to this configuration, the amount of the upstream seal exposed from the lower film can be increased, so that the upstream convex portion can more actively return the toner into the housing.

[0015] The inclined portion may be located inward of an outer end of the upstream seal in the axial direction.

[0016] According to this configuration, the amount of the upstream seal exposed from the lower film can be increased, so that the upstream convex portion can more actively return the toner into the housing.

[0017] The lower film may also have a first edge extending outward in the axial direction from the outer axial end of the inclined portion, a second edge extending upstream in the movement direction from the outer axial end of the first edge, and a third edge extending outward in the axial direction from the upstream end of the second edge in the movement direction, and the first edge, second edge, and third edge may overlap the upstream seal.

[0018] With this configuration, the notch formed by the second edge and the third edge increases the amount of the upstream seal exposed from the lower film, allowing the upstream convex portion to more actively return toner to the housing. Also, the upstream seal can be held in place by the area having the first edge and the second edge, preventing the upstream seal from detaching from the housing.

[0019] At least a portion of the inclined portion may be located within a range of the downstream seal in the axial direction.

[0020] Furthermore, an inner end of the downstream seal in the axial direction may be located within a range of the inclined portion in the axial direction.

[0021] The upstream seal may also be made of a woven fabric.

[0022] In addition, the downstream seal has a plurality of downstream protrusions extending in an inclined direction so as to be positioned more inward in the axial direction as it moves downstream in the movement direction, and the upstream protrusions are composed of a plurality of bristles extending from a base, and the length of the bristles may be greater than the step of the downstream protrusions.

[0023] The downstream seal may also be made of felt. [Effects of the Invention]

[0024] According to the present invention, the toner that has accumulated in excess on the developing roller can be actively returned to the inside of the housing. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 2 is a cross-sectional view showing a developing device according to the embodiment. [Figure 2] FIG. 2 is a perspective view showing a state in which a developing roller is removed from the developing device. [Figure 3](a) is a diagram showing the relationship between the lower film and the side seal, (b) is an oblique view showing the downstream seal, (c) is an oblique view showing the upstream seal, and (d) is a diagram showing the relationship between the inclined portion of the lower film and the bristles of the upstream seal. [Figure 4] 10(a) to 10(c) are diagrams showing the effects of the lower film and the side seal. DETAILED DESCRIPTION OF THE INVENTION

[0026] Next, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. 1, the developing device 1 is a developing cartridge that can be attached to and detached from the main body housing of the image forming apparatus. The developing device 1 includes a housing 10, a developing roller 20, a supply roller 30, a layer thickness regulating blade 40, and an agitator 50.

[0027] The housing 10 is capable of containing toner and supports the developing roller 20, the supply roller 30, the layer thickness regulating blade 40, and the agitator 50.

[0028] The developing roller 20 extends in the axial direction and is rotatable relative to the housing 10. The developing roller 20 has a developing roller shaft 21 extending in the axial direction and a roller portion 22 located on the outer circumferential surface of the developing roller shaft 21. The developing roller shaft 21 may pass through the roller portion 22, or may be provided at each end of the roller portion 22. In the following description, the "outer circumferential surface of the developing roller 20" refers to the outer circumferential surface of the roller portion 22. Furthermore, the "axial end of the developing roller 20" refers to the axial end of the roller portion 22. The supply roller 30 extends in the axial direction and is rotatable relative to the housing 10. The supply roller 30 supplies toner to the developing roller 20. The agitator 50 rotates within the housing 10 and agitates the toner within the housing 10.

[0029] In the developing device 1, the toner contained in the housing 10 is agitated by the agitator 50, and then supplied to the developing roller 20 by the supply roller 30. The toner carried on the outer peripheral surface of the developing roller 20 is regulated to a constant thickness by the layer thickness regulating blade 40.

[0030] As shown in FIG. 2, the housing 10 of the developing device 1 has an opening 11 for supplying toner to the developing roller 20. The developing roller 20 is attached to the housing 10 so as to cover the opening 11. In the following description, the movement direction of the portion of the outer circumferential surface of the developing roller 20 that faces the opening 11 will also be simply referred to as the "movement direction." Note that the movement direction also refers to the movement direction of the portion of the outer circumferential surface of the developing roller 20 that comes into contact with a side seal 70, which will be described later. A portion of the outer circumferential surface of the developing roller 20 moves so as to pass through a lower film 60, the opening 11, and a layer thickness regulating blade 40, which will be described later, in that order.

[0031] The structure around the opening 11 of the developing device 1 is symmetrical in the axial direction. In the following explanation, the structure around the opening 11 of the developing device 1 will be explained by representing the structure on one end side in the axial direction, and the explanation of the structure on the other end side in the axial direction, which is similarly configured, will be omitted.

[0032] The thickness-regulating blade 40 has a blade plate 41 and a blade rubber portion 42 fixed to the blade plate 41 .

[0033] The blade plate 41 is a plate-shaped metal plate extending in the axial direction and is located downstream of the opening 11 in the movement direction.

[0034] The blade rubber portion 42 is a rubber member that extends in the axial direction and has an axial size smaller than that of the blade plate 41, and is formed of, for example, silicone rubber or urethane rubber. The blade rubber portion 42 protrudes from the upstream end of the blade plate 41 in the movement direction toward the developing roller 20 and is in contact with the developing roller 20.

[0035] The blade rubber portion 42 has a recess 42A at one end in the axial direction. The recess 42A is formed so as to be recessed from the downstream edge of the blade rubber portion 42 in the movement direction. The recess 42A is spaced a predetermined distance from one end surface 42B of the blade rubber portion 42 in the axial direction. The portion of the blade rubber portion 42 where the recess 42A is not formed has a substantially semicircular cross section, and the arc portion can come into contact with the developing roller 20. The portion of the recess 42A has a substantially quarter-circular cross section, and the pointed end of the arc can come into contact with the developing roller 20. As a result, the bottom portion of the recess 42A is more angular than the portion of the blade rubber portion 42 other than the recess 42A, making it easier to scrape off toner carried on the developing roller 20.

[0036] The developing device 1 further includes a lower film 60 and a side seal 70. The lower film 60 is a film-like member that extends in the axial direction. The lower film 60 is made of a resin such as polyethylene terephthalate. The lower film 60 is located on the upstream side of the opening 11 in the movement direction. The lower film 60 contacts the outer peripheral surface of the developing roller 20.

[0037] One axial end of the lower film 60 overlaps with an upstream seal 72, which will be described later, of the side seal 70. More specifically, one axial end of the lower film 60 contacts the surface of the upstream seal 72 on the developing roller 20 side.

[0038] The side seal 70 is a member that comes into contact with one end in the axial direction of the outer peripheral surface of the developing roller 20. The side seal 70 has a base layer 71, an upstream seal 72, and a downstream seal 73.

[0039] The base layer 71 is located on one axial end side of the opening 11. The base layer 71 is made of an elastic material such as urethane sponge. The base layer 71 is disposed between the housing 10 and one axial end of the developing roller 20 in a roughly C-shape as viewed in the axial direction, following the shape of the outer circumferential surface of the developing roller 20. The base layer 71 is fixed to the housing 10 with double-sided tape or the like.

[0040] The upstream seal 72 is fixed with double-sided tape or the like to the surface of the base layer 71 on the side of the developing roller 20. The upstream seal 72 contacts one end of the outer circumferential surface of the developing roller 20 in the axial direction.

[0041] The downstream seal 73 is located downstream of the upstream seal 72 in the direction of movement. The downstream seal 73 is fixed to the blade plate 41 of the layer thickness regulating blade 40 with double-sided tape or the like. The downstream seal 73 extends from a position downstream of the blade rubber portion 42 in the direction of movement to a position upstream of the blade rubber portion 42 in the direction of movement. The portion of the downstream seal 73 that extends upstream of the blade rubber portion 42 in the direction of movement overlaps and contacts the surface of the upstream seal 72 on the developing roller 20 side. The downstream seal 73 also contacts one end face 42B of the blade rubber portion 42 in the axial direction.

[0042] As shown in FIG. 3(c), the upstream seal 72 is made of pile fabric, an example of a fabric. More specifically, the upstream seal 72 has a plurality of bristles F, which are fibrous members, formed by cutting a plurality of loop-shaped piles that make up the pile fabric. The bristles F extend from a substrate B. The length of the bristles F is greater than the step L1 of the downstream protrusions 73A, which will be described later and are shown in FIG. 3(b). The bristles F are tilted in a direction inclined relative to the direction of movement, thereby forming a plurality of upstream protrusions 72A.

[0043] The upstream convex portion 72A is located on the surface of the upstream seal 72 that comes into contact with the outer peripheral surface of the developing roller 20. As shown in Fig. 3(a), the upstream convex portion 72A extends in an inclined direction so as to be positioned inward in the axial direction as it moves downstream in the direction of movement. As shown in Fig. 3(d), when the lower film 60 overlaps the surface of the upstream seal 72 that faces the developing roller 20, the tips of the bristles F protrude further toward the developing roller 20 than the lower film 60.

[0044] As shown in Figure 3(a), the lower film 60 has an inclined portion Eg at its edge overlapping the upstream seal 72, which inclines so as to be positioned axially inward as it moves downstream in the direction of movement. The inclination angle θ1 of the upstream convex portion 72A relative to the direction of movement is greater than the inclination angle θ2 of the inclined portion Eg relative to the direction of movement. Because θ1 > θ2 in this manner, as shown in Figure 3(d), multiple bristles F climb onto the inclined portion Eg, and a wall W (see the thick line in Figure 4) made up of multiple bristles F and extending along the inclined portion Eg is formed on the surface of the inclined portion Eg facing the developing roller 20.

[0045] The inclined portion Eg is located inside the axial outer end of the upstream seal 72. The entire inclined portion Eg overlaps with the upstream seal 72. The inclined portion Eg is located within the range of the downstream seal 73 in the axial direction. Furthermore, the inner axial end of the downstream seal 73 is located within the range of the inclined portion Eg in the axial direction. In this embodiment, the inner axial end of the downstream seal 73 is located at the same position in the axial direction as the inner axial end of the inclined portion Eg.

[0046] In addition to the aforementioned inclined portion Eg, the lower film 60 further has a first edge E1, a second edge E2, a third edge E3, a fourth edge E4, a fifth edge E5, and a sixth edge E6 as parts that make up the edge.

[0047] The first edge E1 extends axially outward from the outer axial end of the inclined portion Eg. The second edge E2 extends axially outward from the outer axial end of the first edge E1 to the upstream side in the movement direction. The third edge E3 extends axially outward from the upstream end of the second edge E2 in the movement direction.

[0048] The fourth edge E4 extends from the outer axial end of the third edge E3 toward the upstream side in the movement direction. The fifth edge E5 extends from the upstream end of the fourth edge E4 toward the inner axial direction. The sixth edge E6 extends from the downstream end of the inclined portion Eg toward the inner axial direction.

[0049] The first edge E1, the second edge E2, the third edge E3, and the sixth edge E6 overlap with the upstream seal 72. More specifically, the first edge E1 and the second edge E2 entirely overlap with the upstream seal 72. The third edge E3 and the sixth edge E6 partially overlap with the upstream seal 72.

[0050] 3(a) and 3(b), the downstream seal 73 has a plurality of downstream protrusions 73A that come into contact with the outer peripheral surface of the developing roller 20. The downstream protrusions 73A extend in an inclined direction so as to be positioned inward in the axial direction as they move downstream in the movement direction.

[0051] The downstream seal 73 is made of felt. The downstream protrusion 73A is formed by pressing a mold onto the surface of a base material made of felt.

[0052] The inclination angle θ3 of the downstream convex portion 73A relative to the movement direction is smaller than the inclination angle θ2 of the inclined portion Eg relative to the movement direction. In other words, the inclination angle θ1 of the upstream convex portion 72A, the inclination angle θ2 of the inclined portion Eg, and the inclination angle θ3 of the downstream convex portion 73A satisfy the following formula (1). θ3<θ2<θ1 (1)

[0053] Each of the inclination angles θ1 to θ3 can be set, for example, within the following ranges, provided that the relationship of formula (1) is satisfied. θ1=30~60° θ2=15~45° θ3=0~20° As an example, θ1=45°, θ2=30°, and θ3=10°.

[0054] Next, the effects of the lower film 60 and the side seal 70 will be described. 4(a), when the developing device 1 is driven, if the toner T attempts to move axially outward between the downstream seal 73 and the developing roller 20, the movement of the toner T is stopped by the downstream convex portion 73A, which has a smaller inclination angle than the inclined portion Eg. As a result, the toner T accumulates near the end of the downstream seal 73 on the inner side in the axial direction.

[0055] Toner T accumulated near the axially inner end of the downstream seal 73 is carried and transported by the outer peripheral surface of the rotating developing roller 20, and moves toward the inclined portion Eg of the lower film 60, as shown in FIG. 4(b). A wall W made up of a plurality of bristles F is formed on the inclined portion Eg. When the toner T reaches the wall W, the wall W guides the toner T axially inward and returns it to the opening 11, as shown in FIG. 4(c). Note that if toner T gets between the upstream seal 72 and the outer peripheral surface of the developing roller 20 while the developing device 1 is in operation, the inclined upstream convex portion 72A returns the toner T to the opening 11.

[0056] As described above, the following effects can be obtained in this embodiment. By making θ1>θ2, the bristles F of the upstream seal 72 climb up onto the inclined portion Eg and form a wall W along the inclined portion Eg, and this wall W can actively return the toner T that has accumulated in excess on the developing roller 20 into the housing 10.

[0057] By making θ2>θ3, the downstream-side convex portion 73A, which has a smaller inclination angle than the inclined portion Eg, can prevent the toner T from leaking outward in the axial direction.

[0058] The toner T blocked by the downstream convex portion 73A, which has a small inclination angle, accumulates within a range near the axially inner end of the downstream seal 73, specifically, within a narrow range in the axial direction. On the other hand, by making the inclination angle of the inclined portion Eg greater than that of the downstream convex portion 73A, the axial range of the wall W formed on the inclined portion Eg becomes larger than the axial width of the toner T blocked by the downstream convex portion 73A. Therefore, the toner T, which has a small axial width, can be more reliably received by the wall W, which has a large axial range, and the toner T can be returned to the housing 10 by the wall W.

[0059] Since the entire inclined portion Eg overlaps with the upstream seal 72, the amount of the upstream seal 72 exposed from the lower film 60 can be increased, and the upstream convex portion 72A can more actively return the toner T into the housing 10.

[0060] By positioning the inclined portion Eg more inward than the axially outer end of the upstream seal 72, the amount of the upstream seal 72 exposed from the lower film 60 can be increased, and the upstream convex portion 72A can more actively return the toner T into the housing 10.

[0061] The cutout formed by the second edge E2 and the third edge E3 of the lower film 60 allows a greater amount of the upstream seal 72 to be exposed from the lower film 60, so that the upstream protrusion 72A can more actively return the toner T into the housing 10. In addition, the upstream seal 72 can be held down by the portion of the lower film 60 that has the first edge E1 and the second edge E2, so that the upstream seal 72 can be prevented from detaching from the housing 10.

[0062] The present invention is not limited to the above-described embodiment, but can be used in various forms as exemplified below.

[0063] In the above embodiment, the downstream seal 73 overlaps the upstream seal 72, but the present invention is not limited to this, and the downstream seal does not have to overlap the upstream seal.

[0064] The upstream seal may be made of a fabric other than pile fabric, or may be made of a material other than fabric, such as felt.

[0065] In the above embodiment, the entire inclined portion Eg is located within the range of the downstream seal 73 in the axial direction, but the present invention is not limited to this, and it is sufficient that at least a portion of the inclined portion is located within the range of the downstream seal in the axial direction.

[0066] The developing device is not limited to a developing cartridge, but may be, for example, a developing device in which a toner cartridge that contains toner is detachably attached.

[0067] The elements described in the above-described embodiment and modified examples may be implemented in any combination. [Explanation of symbols]

[0068] 1. Developing device 10. Cabinet 20 Developing roller 60 Lower Film 70 Side seal 72 Upstream seal 72A Upstream convex part 73 Downstream seal Eg inclined part θ1 Tilt angle θ2 Tilt angle

Claims

1. a housing capable of containing toner; a developing roller extending in an axial direction and rotatable relative to the housing; a lower film extending in the axial direction and in contact with an outer peripheral surface of the developing roller; a side seal that comes into contact with one end of the outer peripheral surface of the developing roller in the axial direction, an upstream seal overlapping one end of the lower film in the axial direction; a downstream seal located downstream of the upstream seal in the direction of movement of the outer circumferential surface of the developing roller; and a side seal having the downstream seal. The upstream seal is a surface that contacts the outer peripheral surface of the developing roller has a plurality of upstream protrusions that extend in an inclined direction so as to be positioned inward in the axial direction as they move downstream in the moving direction; the lower film has an inclined portion at an edge overlapping the upstream seal, the inclined portion inclining toward the inside in the axial direction as it goes downstream in the moving direction, a tilt angle of the upstream convex portion relative to the movement direction being greater than a tilt angle of the inclined portion relative to the movement direction;

2. the upstream seal is made of a fibrous material, 2. The developing device according to claim 1, wherein the tip of the fibrous member protrudes beyond the lower film.

3. The downstream seal is a plurality of downstream protrusions extending in an inclined direction so as to be positioned inward in the axial direction as they extend downstream in the movement direction, 3. The developing device according to claim 1, wherein an angle of inclination of the downstream convex portion with respect to the movement direction is smaller than an angle of inclination of the inclined portion with respect to the movement direction.

4. 4. The developing device according to claim 1, wherein the inclined portion entirely overlaps the upstream seal.

5. 5. The developing device according to claim 1, wherein the inclined portion is positioned inside an outer end of the upstream seal in the axial direction.

6. The lower film is a first edge extending outward in the axial direction from an outer end of the inclined portion in the axial direction; a second edge extending from an outer end of the first edge in the axial direction to an upstream side in the movement direction; a third edge extending outward in the axial direction from an end of the second edge on the upstream side in the movement direction, 6. The developing device according to claim 5, wherein the first edge, the second edge, and the third edge overlap the upstream seal.

7. 7. The developing device according to claim 1, wherein at least a portion of the inclined portion is located within a range of the downstream seal in the axial direction.

8. 8. The developing device according to claim 7, wherein an inner end of the downstream seal in the axial direction is located within a range of the inclined portion in the axial direction.

9. 9. The developing device according to claim 1, wherein the upstream seal is made of a woven fabric.

10. The downstream seal is a plurality of downstream protrusions extending in an inclined direction so as to be positioned inward in the axial direction as they extend downstream in the movement direction, the upstream convex portion is composed of a plurality of bristles extending from a substrate; 10. The developing device according to claim 1, wherein the length of the bristles is greater than the step of the downstream-side convex portion.

11. 11. The developing device according to claim 1, wherein the downstream seal is made of felt.

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