JP2010128339A - Developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device that prevents the developer leaked from the outer peripheral surfaces of both ends in the longitudinal direction of a developer carrier from leaking out of a casing, and to provide an image forming apparatus with the developing device. <P>SOLUTION: In a development cartridge 6, side seals 45 which prevent toner from leaking from the outer peripheral surfaces of both ends in the width direction of a developing roller 5 are provided to both sides of an opening 23 in the width direction. In a development casing 20 of the development cartridge 6, a toner pocket 53 which dams up the toner leaking from the outer peripheral surface of both ends in the width direction of the developing roller 5 is provided at an upstream portion 32E upstream in the rotation direction X of the developing roller 5 in relation to the side seals 45. Since the toner pocket 53 is provided integrally to the upstream side portion 32E of the development casing 20, there is no gap communicating outside the development casing 20 between the toner pocket 53 and the development casing 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a laser printer, and a developing device provided in the image forming apparatus.

As an image forming apparatus, a laser beam printer having a developing device that develops an electrostatic latent image on a photosensitive drum is known (for example, see Patent Document 1).
In the laser beam printer described in Patent Document 1, the developing device includes a toner container in which toner is accommodated and a developing container in which a developing roller is accommodated. The developing roller is rotatably supported by the developing container via developing bearings attached to both ends of the developing container in the longitudinal direction. The toner in the toner container is carried on the outer peripheral surface of the developing roller, and then adheres to the electrostatic latent image on the photosensitive drum to develop the electrostatic latent image.

In the developing container, a collecting member is provided in the vicinity of both ends in the longitudinal direction of the developing roller to collect toner leaked from the outer peripheral surfaces of both ends in the longitudinal direction of the developing roller. In the developing container, toner leakage protection walls are provided on both side surfaces in the longitudinal direction of the developing roller. The outer end surface of the collecting member is in contact with the corresponding toner leakage protective wall, whereby the toner leakage path is blocked, and toner that cannot be collected by the collecting member is separated between the collecting member and the toner leakage protective wall. Leakage from the gap is prevented.
JP 2003-228234 A

In the developing device described in Patent Document 1, the toner leakage protection wall is integrally installed on the developing bearing attached to the developing container or the cover of the developing bearing, in other words, separate from the developing container. is there.
Therefore, a gap is inevitably generated between the toner leakage protection wall and the developing container. Therefore, even if the toner leakage path is interrupted by bringing the collecting member into contact with the toner leakage protection wall, the toner leakage protection wall and the developing container. The toner may leak from the gap to the outside of the developing container. If toner leaking from the gap adheres to the recording medium, the quality of the image formed on the recording medium may be adversely affected.

  An object of the present invention is to provide a developing device that can prevent the developer leaking from the outer peripheral surfaces of both ends in the longitudinal direction of the developer carrying member from leaking out of the casing, and an image forming apparatus including the developing device. It is in.

  In order to achieve the above-mentioned object, the invention according to claim 1 is a developing device which contains a developer and has a housing in which an opening is formed, and is rotatably supported by the housing in the opening. A developer carrier that carries a developer on an outer peripheral surface; and provided in both sides of the opening in the longitudinal direction of the developer carrier in the casing, at both ends in the longitudinal direction of the developer carrier. A seal member that is in contact with the outer peripheral surface and prevents the developer from leaking from the outer peripheral surface at both ends in the longitudinal direction of the developer carrier; and in the housing, in the upstream of the rotation direction of the developer carrier relative to the seal member The developer is integrally provided in the upstream portion on the side, faces the outer peripheral surfaces of both ends in the longitudinal direction of the developer carrier, and blocks the developer leaking from the outer peripheral surfaces of both ends in the longitudinal direction of the developer carrier. It has a damming part It is set to.

According to a second aspect of the present invention, in the first aspect of the present invention, the damming portion has an outer periphery of the developer carrying member as compared to a portion around the damming portion in the upstream portion. It is characterized by being recessed in a direction away from the surface.
According to a third aspect of the present invention, in the first or second aspect of the present invention, a wall projecting toward the outer peripheral surface side of the developer carrying member at the upstream end of the dam portion in the rotation direction. It is characterized in that a part is provided.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the wall portion is provided on an end surface on the upstream side in the rotation direction, and is closer to the outer peripheral surface side of the developer carrier than the wall portion. A protruding film member is provided.
The invention according to claim 5 is the invention according to claim 4, wherein the film member includes an end surface on the upstream side in the rotational direction in the wall portion of the damming portion on the one end side in the longitudinal direction, It is constructed between the wall portion of the damming portion on the other end side in the longitudinal direction and the end surface on the upstream side in the rotation direction.

According to a sixth aspect of the present invention, in the invention according to the fourth or fifth aspect, the end surface on the upstream side in the rotational direction of the wall portion is the rotational direction in the portion of the casing that borders the opening. It is characterized by being flush with the upstream end face.
The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the housing is provided with a first chamber in which the developer carrier is disposed and the developer carrier. A partition wall partitioned into a second chamber in which a developer to be supplied is accommodated; and the housing includes a first frame provided with the partition wall, and a second frame provided with the blocking portion. It can be divided into two.

  According to an eighth aspect of the present invention, there is provided an image forming apparatus comprising the developing device according to any one of the first to seventh aspects.

According to the first and eighth aspects of the present invention, in this developing device, the developer carrier is rotatably supported by the housing at the opening. The developer accommodated in the housing is carried on the outer peripheral surface of the developer carrying member.
In the housing, the seal members provided on both sides of the opening in the longitudinal direction of the developer carrying member (hereinafter sometimes simply referred to as “longitudinal direction”) are both longitudinal ends of the developer carrying member. The developer is prevented from leaking from the outer peripheral surfaces of both ends in the longitudinal direction of the developer carrying member.

Further, in the casing, a damming portion is provided in an upstream portion on the upstream side in the rotation direction of the developer carrying member with respect to the seal member (hereinafter, simply referred to as “rotation direction”). The damming portions oppose the outer peripheral surfaces at both ends in the longitudinal direction of the developer carrying member, and dam the developer leaking from the outer peripheral surfaces at both longitudinal ends of the developer carrying member.
Here, the blocking portion is provided integrally with the upstream portion of the housing. In other words, since the damming portion is not a separate body from the housing, there is no gap communicating between the damming portion and the housing outside the housing. Therefore, it is possible to prevent the developer leaking from the outer peripheral surfaces at both end portions in the longitudinal direction of the developer carrying member from leaking out of the housing in the middle of the damming portion or in the state of being dammed by the damming portion.

According to the second aspect of the present invention, the damming portion is recessed in the direction away from the outer peripheral surface of the developer carrying member as compared with the portion around the damming portion in the upstream portion of the housing. The developer leaking from the outer peripheral surfaces at both ends in the longitudinal direction of the developer carrier can be collected, and the developer can be reliably dammed up.
According to the third aspect of the present invention, since the wall portion projecting toward the outer peripheral surface side of the developer carrier is provided at the upstream end portion in the rotation direction of the damming portion, the damming portion is dammed. Even when the developer flows upstream in the rotation direction at the damming portion, the flow of the developer is blocked by the wall portion. Thereby, it is possible to prevent the developer from leaking from the damming portion.

  According to the fourth aspect of the present invention, a film member is provided on the end surface of the wall portion on the upstream side in the rotation direction so as to protrude from the wall portion toward the outer peripheral surface side of the developer carrier. Therefore, even if the developer blocked by the blocking portion flows upstream in the rotation direction at the blocking portion, the flow of the developer is blocked not only by the wall portion but also by the film member. Thereby, it is possible to reliably prevent the developer from leaking from the damming portion.

  According to invention of Claim 5, a film member is the rotation direction in the end face of the rotation direction upstream in the wall part of the damming part of a longitudinal direction one end side, and the rotation direction in the wall part of the damming part of a longitudinal direction other end side It is installed between the end face on the upstream side. Therefore, even if the developer existing in the region sandwiched between the end faces on both ends in the longitudinal direction in the upstream portion of the casing flows to the upstream side in the rotation direction, the film member blocks the flow of the developer. It is possible to prevent the developer from leaking out of the housing.

  According to the sixth aspect of the present invention, the end surface on the upstream side in the rotation direction of the wall portion is flush with the end surface on the upstream side in the rotation direction at the portion bordering the opening in the housing. The film members can be attached to both end faces at once without bending. Thereby, the effort which attaches a film member separately with respect to each end surface can be saved.

The film member attached to the end face on the upstream side in the rotation direction in the portion bordering the opening in the casing blocks the flow of the developer toward the upstream side in the rotation direction near the opening, so that the developer is removed from the opening. It is possible to prevent leakage outside the housing.
According to the seventh aspect of the present invention, the housing includes a first chamber in which the developer carrier is disposed and a second chamber in which the developer to be supplied to the developer carrier is accommodated by the partition wall. It is divided into and. The housing can be divided into a first frame provided with a partition wall and a second frame provided with a damming portion.

  If the second frame has a partition wall, the second frame has a relatively complicated shape. For example, when the second frame is molded with a mold, the mold of the second frame also becomes complicated. Accordingly, the blocking portion must be separated from the second frame (that is, the housing). However, since the partition wall is provided in the first frame instead of the second frame, the molds of the second frame and the second frame have a relatively simple shape, so that the damming portion is provided integrally with the second frame. be able to.

1. Printer FIG. 1 is a side sectional view showing an embodiment of a printer as an example of an image forming apparatus of the present invention. In addition, when referring to a direction, the illustrated direction arrow is referred to (the same applies to other drawings). Here, the horizontal direction and the width direction are the same, and the vertical direction and the vertical direction are the same. The horizontal direction includes the width direction and the front-rear direction.

  The printer 1 is a color printer. As shown in FIG. 1, the printer 1 includes a substantially box-shaped main body casing 2 that is long in the front-rear direction. In the main casing 2, four photosensitive drums 3 are arranged in parallel along the front-rear direction in a rotatable state. Each photosensitive drum 3 is provided with a scorotron charger 4 and a developing roller 5 as an example of a developer carrier. Further, a developing cartridge 6 that holds the developing roller 5 and accommodates toner as an example of a developer is disposed adjacent to each photosensitive drum 3. The developing cartridge 6 functions as an example of a developing device, and there are four developing cartridges 6 like the photosensitive drum 3. Each developing cartridge 6 is detachably attached to the main casing 2. In each developing cartridge 6, toner is carried on the surface (outer peripheral surface) of the developing roller 5.

  At the time of image formation, the surface of each photosensitive drum 3 is uniformly charged by the charger 4, and then the laser beam is emitted from the scanner unit 7 provided on the upper portion of the main body casing 2 (see the broken arrow in the drawing). Exposed. Thereby, an electrostatic latent image based on the image data is formed on the surface of each photosensitive drum 3. The electrostatic latent image on each photosensitive drum 3 is visualized by toner carried on the surface of the developing roller 5 corresponding to each photosensitive drum 3, and a toner image is formed on the surface of each photosensitive drum 3. The Here, since the color of the toner stored in each developing cartridge 6 differs depending on each developing cartridge 6, the color of the toner image on each photosensitive drum 3 differs depending on each photosensitive drum 3.

  The sheets S as an example of the recording medium are accommodated in the sheet cassette 8 disposed at the bottom of the main body casing 2 so as to be stacked in the vertical direction. At the time of image formation, the uppermost sheet S among the sheets S accommodated in the sheet cassette 8 is fed rearward by a sheet feed roller 9 provided so as to face the rear end portion of the sheet cassette 8 from above. It is. The fed paper S rises while changing its direction from the rear side to the front side.

The raised sheet S enters between the pair of registration rollers 10. The pair of registration rollers 10 sends the paper S toward the front conveyor belt 11 at a predetermined timing.
The conveyor belt 11 is endless, and four transfer rollers 12 are arranged in the inner region. The four transfer rollers 12 are arranged in parallel along the front-rear direction, and each transfer roller 12 faces the corresponding photosensitive drum 3 from below with the upper portion of the transport belt 11 in between.

  The paper S sent out from the pair of registration rollers 10 is delivered to the upper part of the transport belt 11. And the conveyance belt 11 conveys the paper S to the front side in the upper part by rotating in the clockwise direction in FIG. The toner image on the surface of each photosensitive drum 3 is transferred onto the sheet S conveyed by the conveyor belt 11 by the transfer bias applied to the transfer roller 12 and is sequentially superimposed. Here, since the color of the toner image on each photosensitive drum 3 differs depending on each photosensitive drum 3, the toner images for four colors are superimposed on the paper S. As a result, a color image is formed on the paper S. Is done.

The sheet S on which the color image is formed is conveyed to the front fixing unit 13 by the conveyance belt 11. Here, the toner image of each photosensitive drum 3 transferred onto the paper S is heat-fixed by the fixing unit 13. Thereafter, the sheet S is transported by the transport roller 14 and is lifted while changing its direction from the front side to the rear side, and is discharged to the sheet discharge tray 15 at the upper part of the main casing 2.
2. Developing Cartridge Hereinafter, the developing cartridge 6 will be described. In the description of the developing cartridge 6, the state when the developing cartridge 6 is mounted on the main body casing 2 is used as a reference. In addition, the four developing cartridges 6 have the same configuration except that the color of the accommodated toner is different. Therefore, in FIG. 1, the developing cartridge 6 is described with reference to the developing cartridge 6 located at the rearmost side. To do.
(1) Outline of Developing Cartridge The developing cartridge 6 mainly includes the developing roller 5, the layer thickness regulating blade 21, and the supply roller 22 in a developing casing 20 as an example of an outer casing. ing.

  The developing casing 20 has a box shape elongated in the width direction in which an opening 23 is formed at the lower end (see FIG. 2 described later). In the developing casing 20, a partition wall 24 extending from the lower end of the front wall 31 of the developing casing 20 to the rear side (the rear wall 32 of the developing casing 20) is provided slightly above the lower end portion. A predetermined gap (referred to as communication port 25) is formed between the rear end of the partition wall 24 and the rear wall 32 of the developing casing 20. In the developing casing 20, a region above the partition wall 24 is a toner storage chamber 26, and a region below the partition wall 24 is a development chamber 27 communicating with the opening 23. That is, the partition wall 24 partitions the inside of the developing casing 20 into the toner storage chamber 26 and the developing chamber 27. The toner storage chamber 26 and the developing chamber 27 communicate with each other through the communication port 25. The toner storage chamber 26 functions as an example of the second chamber, and the developing chamber 27 functions as an example of the first chamber. The developing casing 20 will be described in detail later.

  The developing roller 5 is long in the width direction. In other words, the axis of the developing roller 5 extends along the width direction. The developing roller 5 includes, for example, a developing roller shaft 5A made of metal and extending in the width direction, and a cylindrical rubber roller 5B that covers the developing roller shaft 5A except for both ends in the width direction. The respective circle centers of the developing roller shaft 5A and the rubber roller 5B coincide with the axis of the developing roller 5. The developing roller 5 is accommodated in the developing chamber 27 and is rotatably supported by the developing casing 20. The axis of the developing roller 5 coincides with the rotation axis of the developing roller 5. The developing roller 5 is exposed to the front lower side in the opening 23 and faces and contacts the corresponding photosensitive drum 3 from the rear upper side. Thus, the developing roller 5 is rotatably supported by the developing casing 20 at the opening 23.

The layer thickness regulating blade 21 includes a leaf spring member 28 formed in a thin plate shape that is long in the width direction, and a pressure contact rubber 29 provided at the rear end portion of the leaf spring member 28. The leaf spring member 28 is opposed to the partition wall 24 described above from the front lower side, and the pressure contact rubber 29 is pressed against the outer peripheral surface of the developing roller 5 (rubber roller 5B) from above by the elastic force of the leaf spring member 28. ing.
The supply roller 22 is long in the width direction, like the developing roller 5. The supply roller 22 is disposed near the boundary between the toner storage chamber 26 and the developing chamber 27 (strictly, below the communication port 25), and is rotatably supported by the developing casing 20. The axis of the supply roller 22 coincides with the rotation axis of the supply roller 22. In this state, the supply roller 22 faces and contacts the developing roller 5 from the upper rear side.

  In the toner storage chamber 26, toner to be supplied to the developing roller 5 is stored. Here, for example, a non-magnetic one-component polymerized toner is used as the toner. The polymerized toner has a substantially spherical shape and good fluidity. An agitator 30 is provided in the toner storage chamber 26. The agitator 30 is rotatable around the rotation axis extending in the width direction in the toner storage chamber 26.

During the image formation described above, the toner in the toner storage chamber 26 is agitated by the rotation of the agitator 30 and falls from the communication port 25 to the developing chamber 27 and is supplied to the supply roller 22. Thereafter, the toner is supplied to the developing roller 5 by the rotation of the supply roller 22. As the developing roller 5 rotates, the toner supplied to the developing roller 5 enters between the pressure contact rubber 29 of the layer thickness regulating blade 21 and the outer peripheral surface of the developing roller 5 (rubber roller 5B). While the layer thickness is restricted, the thin film is carried on the outer peripheral surface of the developing roller 5 as a thin layer.
(2) Details of Developing Cartridge FIG. 2 is a perspective view of the developing casing of the developing cartridge as viewed from the left front side. 3A is a front view of the developing casing, and FIG. 3B is a cross-sectional view taken along line AA in FIG. FIG. 4 shows a state where a side seal is attached to the developing casing in FIG. FIG. 5 shows a state in which the developing roller is added with a dotted line in FIG. FIG. 6 shows a state in which the developing roller and the gear cover are attached to the developing casing in FIG. FIG. 7 is a perspective view of the developing cartridge as viewed from the right front side.

In the following description, the rotation direction of the developing roller 5 is indicated by the thick dotted line arrow in FIG. 1 (see the frontmost developing cartridge 6). The thickness regulating blade 21 and the photosensitive drum 3 are sequentially opposed to each other (the clockwise direction in the left side view). Further, the upstream side and the downstream side in the rotation direction of the developing roller 5 are two positions in the direction along the circumferential direction of the developing roller 5 (including the tangential direction with respect to the circumferential direction) with respect to the rotational direction of the developing roller 5. The relative positional relationship of is shown.
(2-1) Developing Casing As shown in FIG. 2, the developing casing 20 includes a left wall 33 and a right wall 34 that are opposed to each other with a gap in the width direction in addition to the front wall 31 and the rear wall 32 described above. And a ceiling wall 35.

  Here, the front wall 31 extends substantially vertically, while the rear wall 32 extends to the lower front side (see the rearmost developing cartridge 6 in FIG. 1). That is, the front-rear distance between the front wall 31 and the rear wall 32 becomes narrower as it goes downward. In the rear wall 32, the middle portion in the vertical direction that coincides with the supply roller 22 bulges in an arc shape toward the rear side along the rear outer peripheral surface of the supply roller 22, and (See also the rearmost developing cartridge 6 in FIG. 1). The lower end edge of the rear wall 32 extends along the width direction.

The left wall 33 is constructed between the left end of the front wall 31 and the left end of the rear wall 32. The right wall 34 is constructed between the right end of the front wall 31 and the right end of the rear wall 32. As described above, since the front-rear distance between the front wall 31 and the rear wall 32 is narrowed downward (see FIG. 1), each of the left wall 33 and the right wall 34 becomes narrower downward. It has a substantially triangular shape.
The top wall 35 closes the portion surrounded by the upper ends of the front wall 31, the rear wall 32, the left wall 33, and the right wall 34 from above.

  The lower end edge of the front wall 31 extends along the width direction and is above the lower ends of any of the rear wall 32, the left wall 33, and the right wall 34. The opening 23 described above is partitioned by the lower end edge of the front wall 31, the lower end edge of the rear wall 32, the lower end part of the left wall 33, and the lower end part of the right wall 34, and is substantially long in the width direction in a front view. It has a rectangular shape. Further, the partition wall 24 continuously extending from the lower end of the front wall 31 to the rear side, the rear wall 32 (specifically, the bulging portion 32A and the lower portion from the bulging portion 32A), the lower end portion of the left wall 33, and the right The space surrounded by the lower end of the wall 34 is the developing chamber 27 described above.

  Each of a lower end portion (referred to as a partition portion 33A) that partitions the opening 23 in the left wall 33 and a lower end portion (referred to as a partition portion 34A) that partitions the opening 23 in the right wall 34 has a respective front edge. A shaft support groove 37 is formed that is cut out from the (portion bordering the opening 23) toward the rear upper side. The shaft support groove 37 of the left wall 33 and the shaft support groove 37 of the right wall 34 substantially coincide with each other when viewed from the width direction. In each shaft support groove 37, the deepest portion 37A (upper end on the rear side) is a fixed position of the developing roller 5 (strictly, the developing roller shaft 5A) (see FIGS. 3B and 5).

  In the developing casing 20, around the opening 23 (in the developing chamber 27), the left wall 33 and the right wall 34 are integrated with the left wall 33 and the right wall 34, respectively. A seal pedestal portion 38 extending inward in the width direction from each width direction inner side surface of 34 is provided. In other words, the seal pedestal portions 38 are provided at both ends of the opening 23 in the width direction in the developing casing 20.

The seal pedestal 38 is a substantially bow-shaped curved surface that is recessed rearward along the outer peripheral surface of the developing roller 5 supported by the developing casing 20 when viewed from the width direction (see also FIG. 3B). . Further, as viewed from the width direction, the shaft support groove 37 is located on the inner side (front region) of the substantially arch-shaped seal pedestal 38 (see FIG. 3B).
Here, in each of the left wall 33 and the right wall 34, the shaft of the supply roller 22 (see FIG. 1) is inserted at a position substantially coincident with the bulging portion 32A of the rear wall 32 when viewed from the width direction. A shaft insertion part 39 is formed. The shaft insertion portion 39 is a hole that penetrates the corresponding wall of the left wall 33 and the right wall 34 in the width direction, and further, the seal pedestal portion 38 on the same side in the width direction is replaced with the lower first surface 38A. And the upper second surface 38B (see also FIG. 3B). As shown in FIG. 3B, in each seal pedestal portion 38, the first surface 38 </ b> A extends from the shaft insertion portion 39 to the front lower side while being curved, and the second surface 38 </ b> B extends from the shaft insertion portion 39. It extends to the front upper side while curving.

  As shown in FIG. 2, the first surface 38A that extends from the shaft insertion portion 39 to the front lower side while being curved is an inner surface 32C (a portion below the bulging portion 32A) of the lower end portion 32B of the rear wall 32. This is the surface facing the developing chamber 27, and the end on the same side in the width direction in the front upper surface) is covered. That is, the concave portions 50 whose bottoms are defined by the corresponding first surfaces 38A are formed at both ends in the width direction of the inner surface 32C.

A wall portion 51 that protrudes to the front upper side is integrally provided at the front end (lower end) of each recess 50 (first surface 38A). The cross-sectional shape of the wall 51 when viewed from the width direction is a substantially triangular shape that narrows toward the front upper side, and closes the front end (lower end) of the corresponding recess 50 from the front lower side.
The front end surfaces 51A of the left and right wall portions 51 are continuous from both sides in the width direction with respect to the front end surface 32D at the lower end of the rear wall 32. The front end surface 51A of the left wall portion 51 is continuous from the right side with respect to the lower end of the front end surface 33B (a portion below the shaft support groove 37) of the partition portion 33A of the left wall 33, and the right wall The front end surface 51A of the portion 51 is continuous from the left side with respect to the lower end of the front end surface 34B (a portion below the shaft support groove 37) of the partition portion 34A of the right wall 34. That is, the front end surface 33B of the left wall 33, the front end surface 51A of the left wall 51, the front end surface 32D of the rear wall 32, the front end surface 51A of the right wall 51, and the front end surface 34B of the right wall 34 (The end surfaces are collectively referred to as the pasting surface 52). The affixing surface 52 has a wide U-shape with the upper side opened when viewed from the front, is a flat surface that extends substantially vertically, and divides the lower side of the opening 23 (FIG. 3B). See also)).

Further, in each of the left wall 33 and the right wall 34, a screw hole 40 is formed in a portion continuous from the front upper side with respect to the second surface 38B of the seal pedestal portion 38.
Here, as described above, the partition wall 24 extending continuously from the lower end of the front wall 31 toward the rear side (specifically, the bulging portion 32A of the rear wall 32) is elongated along the width direction, and the left wall 33 and the right wall 34. In this state, when viewed from the width direction, the partition wall 24 is located near the respective screw holes 40 of the left wall 33 and the right wall 34 (see FIG. 3B).

  Then, as shown in FIG. 6, screws 41 are inserted into both ends in the width direction of the leaf spring member 28 of the layer thickness regulating blade 21, and each screw 41 is matched in the width direction with a screw hole 40 (see FIG. 2). ), The layer thickness regulating blade 21 is installed between the left wall 33 and the right wall 34, and is fixed to the left wall 33 and the right wall 34. In this state, the leaf spring member 28 faces the partition wall 24 from the front lower side as described above. Note that the gap between the partition wall 24 and the leaf spring member 28 and the gap between each of the left wall 33 and the right wall 34 and the leaf spring member 28 are closed by a sponge or the like (in FIG. 6, the partition wall 24 shows a sponge 36 that closes the gap between the plate spring member 28 and the leaf spring member 28).

Here, as shown in FIG. 3B, in the developing casing 20, the partition wall 24 and the front wall 31 are integrated to form a first frame 42 (see a portion filled with dots), The first frame 42 can be separated from a portion (referred to as a second frame 43) other than the first frame 42 in the developing casing 20. The second frame 43 (refer to a portion that is not filled with dots in the developing casing 20) alone has a tray shape in which the front side is fully open. The first frame 42 and the second frame 43 are molded by their dedicated molds. Since the recess 50 described above is formed in the rear wall 32 on the second frame 43 side, the developing casing 20 includes a first frame 42 provided with the partition wall 24 and a second frame provided with the recess 50. It can be seen that the frame 43 can be divided.
(2-2) Side Seal Referring to FIG. 4, in the developing casing 20, the toner carried on the developing roller 5 (see FIG. 1) is placed on both sides of the opening 23 in the width direction. A pair of side seals 45 is provided as an example of a seal member for preventing leakage from the outer peripheral surfaces of both ends in the direction to the outside of the developing casing 20. In FIG. 4, only the right side seal 45 is shown (the same applies to FIG. 5 described later).

The side seal 45 is formed in a belt-like sheet shape, and includes a first layer 45A and a second layer 45B. The side seal 45 is long along the creeping direction of the substantially arch-shaped seal pedestal 38.
The first layer 45A has a relatively large thickness and is made of an elastic foam material such as urethane sponge.

The second layer 45B is made of, for example, a felt material. The second layer 45B has substantially the same shape as the first layer 45A, but is thinner than the first layer 45A and slightly narrower than the first layer 45A. The second layer 45B is attached to the first layer 45A in a state of being disposed so as to overlap the first layer 45A. Thereby, the first layer 45A and the second layer 45B are integrated.
Such a side seal 45 is attached to each seal pedestal portion 38 of the left wall 33 and the right wall 34 (in FIG. 4, the side seal 45 is attached only to the seal pedestal portion 38 of the right wall 34. Status.)

  Specifically, in the seal pedestal portion 38, the first layer 45A of the side seal 45 is cut across the first surface 38A and the second surface 38B (in the seal pedestal portion 38, the shaft insertion portion 39 is cut). It is stuck via a double-sided tape (not shown) so as to close the part. In this state, the entire side seal 45 is curved along the seal pedestal portion 38 when viewed from the width direction, and has a substantially bow shape recessed backward. Further, in the side seal 45, the first layer 45A faces the corresponding seal pedestal portion 38 from the front side, and the second layer 45B is located on the opposite side of the seal pedestal portion 38 with respect to the first layer 45A. The opening 23 is exposed to the front side.

  In addition, at least the second layer 45B protrudes from the concave portion 50 in the portion of the side seal 45 attached to the first surface 38A (projects toward the front upper side toward the inside of the developing chamber 27 from the inner surface 32C of the rear wall 32). ) In the recess 50. At this time, the side seal 45 does not exist in the region of the front end (lower end) of the left and right (right side in FIG. 4) concave portions 50, and this region is an empty space, and a toner pocket as an example of a damming portion. 53.

FIG. 5 shows a state where the side seal 45 is attached to the developing casing 20 and the developing roller 5 is further attached to the developing casing 20.
Regarding the mounting of the developing roller 5 to the developing casing 20, referring to FIG. 5, first, after the developing roller 5 is disposed to face the opening 23 from the front side, both ends of the developing roller 5 in the width direction of the developing roller shaft 5 </ b> A. The part is fitted from the front side into the shaft support groove 37 of the wall on the same side in the width direction of the left wall 33 and the right wall 34. At this time, in the developing roller 5, the outer peripheral surfaces of both end portions in the width direction of the rubber roller 5 </ b> B are opposite to the seal pedestal portion on the same side in the width direction among the seal pedestal portion 38 of the left wall 33 and the seal pedestal portion 38 of the right wall 34. Facing from the front side. Then, both end portions in the width direction of the developing roller shaft 5A are continuously fitted in the corresponding shaft support grooves 37, and both end portions in the width direction of the developing roller shaft 5A reach the deepest portion 37A of the corresponding shaft support groove 37 (FIG. 3). (See also (b)), the mounting of the developing roller 5 to the developing casing 20 is completed.

  In the state where the mounting of the developing roller 5 to the developing casing 20 is completed, as shown in FIG. 5, in the developing roller 5, both ends of the developing roller shaft 5 </ b> A in the width direction are the left wall 33 and the right wall 34 in the width direction. Is fitted in the deepest portion 37A of the shaft support groove 37 on the wall on the same side (see also FIG. 3B). Strictly speaking, as shown in FIG. 6, each of both end portions in the width direction of the developing roller shaft 5A has a deepest portion 37A (see FIG. 5) of the corresponding shaft support groove 37 with the bearing 46 attached. In this state, the developing roller 5 is rotatably supported by the left wall 33 and the right wall 34 of the developing casing 20 via the bearings 46.

  In this state, as shown in FIG. 5, in the developing roller 5, the outer peripheral surface on the rear side of both end portions in the width direction of the rubber roller 5 </ b> B (refer to the right end portion of the rubber roller 5 </ b> B in FIG. 5) The side seal 45 attached to the seal pedestal portion 38 is in contact with the seal pedestal portion 38, and the side seal 45 is pressed toward the seal pedestal portion 38 from the front side. That is, the side seal 45 adhered to the seal pedestal portion 38 is compressed by the seal pedestal portion 38 on the same side in the width direction and the outer peripheral surface of the end portion in the width direction of the rubber roller 5B. As a result, the side seal 45 closes the gap between the seal pedestal portion 38 on the same side in the width direction and the outer peripheral surface of the end portion in the width direction of the rubber roller 5B. Here, in the side seal 45, the second layer 45B is in close contact with the outer peripheral surface of the end portion in the width direction of the rubber roller 5B along the outer peripheral surface of the end portion in the width direction of the rubber roller 5B. Further, the side seal 45 is compressed and extends along the creeping direction of the seal pedestal portion 38, and the front upper end reaches the layer thickness regulating blade 21 (see FIGS. 6 and 7). ).

  When the developing roller 5 rotates in this state, the second layer 45B of each side seal 45 rubs against the rear outer peripheral surface of both end portions in the width direction of the developing roller 5 (rubber roller 5B). As a result, toner leaks from the region sandwiched between the second layers 45B of the left and right side seals 45 (only the right side seal 45 is shown in FIG. 5) on the outer peripheral surface of the rubber roller 5B to the outside in the width direction. Is prevented.

Here, the rotation direction of the developing roller 5 described above (see the thick dotted line arrow in FIG. 1) is the front and lower side of the side seal 45 while being curved along the side seal 45 as shown by the thick dotted line arrow in FIG. The direction is from the side toward the front upper side.
In the lower end portion 32B of the rear wall 32 of the developing casing 20, when a portion on the upstream side in the rotation direction of the developing roller 5 with respect to each side seal 45 is defined as an upstream portion 32E, the upstream portion 32E is the lower end of the rear wall 32. It is the most front lower part of the part 32B. The left and right toner pockets 53 are provided (formed) integrally with the upstream portion 32E, and face the outer peripheral surfaces at both ends in the width direction of the developing roller 5 (rubber roller 5B) from below. Each toner pocket 53 is adjacent to the side seal 45 on the same side in the width direction from the upstream side in the rotation direction of the developing roller 5.

  Here, the configuration and the like of the toner pocket 53 will be described with reference to the rotation direction of the developing roller 5 (hereinafter simply referred to as “rotation direction X”) and the upstream portion 32E. First, the toner pocket 53 is recessed in the direction away from the outer peripheral surface of the developing roller 5 (lower side) as compared with the portion around the toner pocket 53 in the upstream portion 32E (that is, the inner surface 32C). Further, the wall portion 51 described above is provided at the upstream end portion in the rotation direction X in the toner pocket 53 and protrudes toward the outer peripheral surface side of the developing roller 5. Further, the front end surface 51A of the wall portion 51 is an upstream end surface in the rotational direction X of the wall portion 51, and an upstream end surface in the rotational direction X in the portion of the developing casing 20 that borders the opening 23 (that is, the left end surface) The front end face 33B of the wall 33, the front end face 32D of the rear wall 32, and the front end face 34B of the right wall 34) are flush with each other.

As described above, when the second layer 45B of each side seal 45 rubs against the outer peripheral surface of both ends in the width direction of the developing roller 5 rotating as described above, the toner that was on the outer peripheral surface of both ends in the width direction of the developing roller 5 Are scraped away from the outer peripheral surfaces at both ends in the width direction of the developing roller 5 toward the upstream side in the rotation direction X by the corresponding side seals 45. As a result, the toner on the outer peripheral surfaces at both end portions in the width direction of the developing roller 5 is peeled off from the outer peripheral surfaces at both end portions in the width direction of the developing roller 5 and leaks upstream in the rotation direction X. Then, the toner leaking from the outer peripheral surfaces of both end portions in the width direction of the developing roller 5 is collected in the upstream of the corresponding side seal 45 in the rotation direction X, that is, in the toner pocket 53 and is blocked by the toner pocket 53.
(2-3) Film Member As shown in FIG. 6, a film member 54 is attached to the developing casing 20. For the film member 54, for example, a PET sheet or a urethane rubber film is used. The film member 54 has a substantially rectangular shape that is long in the width direction, and both end portions and lower end portions in the width direction are portions that define the above-described pasting surface 52 (the lower side of the opening 23 in the developing casing 20). 5)) with a double-sided tape (not shown).

Here, since the sticking surface 52 includes the front end surfaces 51A of the left and right wall portions 51 as described above, it can be seen that the film member 54 is provided on the front end surface 51A.
In FIG. 6, the edge (upper edge) on the outer peripheral surface side of the developing roller 5 on the front end surface 51 </ b> A of each of the left and right wall portions 51 and the front end surface 32 </ b> D of the rear wall 32 is indicated by a dotted line. Protrudes toward the outer peripheral surface of the developing roller 5 from each wall 51. The film member 54 has a front end surface 51A of the wall portion 51 of the toner pocket 53 on one end side (left side) in the width direction and a front end surface 51A of the wall portion 51 of the toner pocket 53 on the other end side (right side) in the width direction. It is built between.

By attaching the film member 54 to the developing casing 20 in this way, the upstream portion 32E (below the opening 23) is partitioned by the rear wall 32, the left wall 33, the right wall 34, and the film member 54. A groove 55 is formed (see also FIG. 3B). The groove 55 extends in the width direction in a state of facing the entire width direction of the outer peripheral surface of the developing roller 5 while being recessed in a direction (lower side) away from the outer peripheral surface of the developing roller 5 (rubber roller 5B). The toner spilled from the outer peripheral surface of the developing roller 5 and the toner overflowing from the toner pocket 53 are collected in the groove 55 and do not leak out of the developing cartridge 6 from the opening 23.
(2-4) Others As shown in FIG. 7, in the developing cartridge 6, a gear mechanism 60 is disposed on the right wall 34 of the developing casing 20. The gear mechanism 60 includes a coupling gear 61, a detection gear 62, and a plurality of other gears (not shown). The gear mechanism 60 receives the driving force from the main casing 2 (see FIG. 1) by the coupling gear 61 and transmits it to the developing roller 5, the supply roller 22 and the agitator 30 (see FIG. 1). Thereby, the developing roller 5, the supply roller 22, and the agitator 30 are rotated. Further, when the developing cartridge 6 is mounted on the main casing 2, the detection gear 62 rotates by a predetermined amount by receiving a driving force from the main casing 2 (in some cases, it does not rotate). Information about the cartridge 6 (whether the developing cartridge 6 is new or not) is input to a control unit (not shown) provided on the main casing 2 side.

The developing cartridge 6 includes a gear cover 63. The gear cover 63 is separate from the developing casing 20 and is attached to the right wall 34 of the developing casing 20 from the right side. The gear mechanism 60 covers portions other than the coupling gear 61 and the detection gear 62 from the right side.
3. Operational Effect (1) As shown in FIG. 5, in the developing cartridge 6, the developing roller 5 is rotatably supported by the developing casing 20 in the opening 23. The toner accommodated in the developing casing 20 is carried on the outer peripheral surface of the developing roller 5 (rubber roller 5B).

In the developing casing 20, side seals 45 (only the right side seal 45 is shown in FIG. 5) provided on both sides of the opening 23 in the longitudinal direction (width direction) of the developing roller 5 are developed rollers. 5 is in contact with the outer peripheral surfaces of both end portions in the width direction of the developing roller 5 and prevents the toner from leaking from the outer peripheral surfaces of both end portions of the developing roller 5 in the width direction.
Further, in the developing casing 20 (specifically, the rear wall 32), a toner pocket 53 is provided in an upstream portion 32E on the upstream side in the rotation direction X of the developing roller 5 with respect to the side seal 45. The toner pockets 53 face the outer peripheral surfaces at both ends in the width direction of the developing roller 5 and block toner leaking from the outer peripheral surfaces at both ends in the width direction of the developing roller 5.

  Here, the toner pocket 53 is provided integrally with the upstream portion 32E of the developing casing 20. In other words, since the toner pocket 53 is not a separate body from the developing casing 20, there is no gap communicating between the toner pocket 53 and the developing casing 20 outside the developing casing 20. Therefore, it is possible to prevent the toner leaking from the outer peripheral surfaces at both ends in the width direction of the developing roller 5 from leaking out of the developing casing 20 in the middle of the toner pocket 53 or in a state where the toner pocket 53 is blocked.

Unlike the present invention, if the toner pocket 53 is provided not on the developing casing 20 but on the gear cover 63 (see FIGS. 6 and 7) described above, the gear cover 63 is separate from the developing casing 20, so that the toner A gap communicating with the outside of the developing casing 20 is inevitably generated between the pocket 53 and the developing casing 20.
(2) The toner pocket 53 is recessed in the direction away from the outer peripheral surface of the developing roller 5 as compared with the portion around the toner pocket 53 in the upstream portion 32E (that is, the inner surface 32C). The toner leaking from the outer peripheral surfaces at both ends in the direction can be collected, and this toner can be reliably dammed up.
(3) Since a wall portion 51 that protrudes toward the outer peripheral surface of the developing roller 5 is provided at the upstream end portion in the rotation direction X of the toner pocket 53, the toner that the toner pocket 53 has blocked is stored in the toner pocket 53. The toner flow is blocked by the wall 51 even if the toner flows to the upstream side in the rotation direction X (the edge side of the opening 23). As a result, the toner can be prevented from leaking out of the toner pocket 53.
(4) As shown in FIG. 6, a film member 54 is provided on the front end surface 51 </ b> A on the upstream side in the rotation direction X of the wall portion 51 so as to protrude from the wall portion 51 toward the outer peripheral surface side of the developing roller 5. . Therefore, even if the toner blocked by the toner pocket 53 flows to the upstream side in the rotation direction X (see FIG. 5) in the toner pocket 53, the toner flow is blocked not only by the wall portion 51 but also by the film member 54. . Thereby, it is possible to reliably prevent the toner from leaking out of the toner pocket 53.
(5) The film member 54 includes a front end surface 51A of the wall portion 51 of the toner pocket 53 on one end side (left side) in the width direction, and a front end surface 51A of the wall portion 51 of the toner pocket 53 on the other end side (right side) in the width direction. It is erected between. Therefore, even if the toner existing in the region sandwiched between the front end surfaces 51A on both ends in the width direction in the upstream portion 32E of the developing casing 20 flows to the upstream side in the rotation direction X (see FIG. 5), the film member 54 Since the toner flow is blocked, the toner in this region can be prevented from leaking out of the developing casing 20.

Of course, the film member 54 may be provided only on the front end face 51 </ b> A of the wall portion 51 of each toner pocket 53 on both ends in the width direction without installing the film member 54.
(6) As shown in FIG. 5, the front end surface 51 </ b> A of each wall portion 51 is an upstream end surface (front end surface 33 </ b> B of the left wall 33, Since the front end face 32D of the wall 32 and the front end face 34B of the right wall 34) are flush with each other, the same film member 54 can be attached to these front end faces at one time without bending (see FIG. 6 and FIG. 7). Thereby, the effort which attaches the film member 54 separately with respect to each front-end surface can be saved.

And the film member 54 (refer FIG. 6 and FIG. 7) attached to the upstream end surface (in other words, the sticking surface 52 mentioned above) of the rotation direction X in the part which borders the opening part 23 in the developing casing 20 is as follows. Since the toner flow toward the upstream side in the rotation direction X is blocked in the vicinity of the opening 23, the toner can be prevented from leaking out of the developing casing 20 from the opening 23.
(7) As shown in FIG. 3B, the developing casing 20 includes a developing chamber 27 in which the developing roller 5 is disposed and toner in which toner to be supplied to the developing roller 5 is accommodated by a partition wall 24. It is partitioned from the storage chamber 26. The developing casing 20 can be divided into a first frame 42 provided with a partition wall 24 and a second frame 43 provided with a toner pocket 53 (see also FIG. 5).

When the second frame 43 has the partition wall 24, the second frame 43 has a relatively complicated shape. Therefore, when the second frame 43 is molded with a mold, the mold of the second frame 43 is also complicated. Accordingly, the toner pocket 53 (see FIG. 5) must be separated from the second frame 43 (that is, the developing casing 20). In this case, the toner pocket 53 is provided in the gear cover 63 (see FIGS. 6 and 7) described above. However, by providing the partition wall 24 in the first frame 42 instead of the second frame 43, the molds of the second frame 43 and the second frame 43 have a relatively simple shape. 53 can be provided integrally.
4). Modification In this printer 1, as shown in FIG. 1, the photosensitive drum 3 is exposed by the laser generated by the scanner unit 7, but instead of the scanner unit 7, the photosensitive drum 3 may be exposed using an LED. . The present invention is applicable not only to color printers but also to all types of image forming apparatuses using toner, including monochrome printers.

1 is a side sectional view showing an embodiment of a printer as an example of an image forming apparatus of the present invention. FIG. 7 is a perspective view of the developing casing of the developing cartridge as viewed from the left front side. (A) is a front view of a developing casing, (b) is an AA arrow sectional view of (a). In FIG. 2, the state which attached the side seal to the developing casing is shown. FIG. 4 shows a state in which the developing roller is added with a dotted line. FIG. 4 shows a state where the developing roller and the gear cover are attached to the developing casing. FIG. 3 is a perspective view of the developing cartridge as viewed from the right front side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer 5 Developing roller 6 Developing cartridge 20 Developing casing 23 Opening 24 Partition wall 26 Toner storage chamber 27 Developing chamber 32C Inner surface 32D Front end surface 32E Upstream portion 33B Front end surface 34B Front end surface 42 First frame 43 Second frame 45 Side seal 51 Wall 51A Front End Surface 53 Toner Pocket 54 Film Member X Rotation Direction

Claims (8)

A housing containing a developer and having an opening formed therein;
A developer carrier that is rotatably supported by the housing in the opening and carries a developer on an outer peripheral surface;
In the housing, provided on both sides of the opening in the longitudinal direction of the developer carrier, and in contact with outer peripheral surfaces of both longitudinal ends of the developer carrier, both longitudinal ends of the developer carrier A seal member for preventing the developer from leaking from the outer peripheral surface of
In the housing, the developer is integrally provided at an upstream portion on the upstream side in the rotation direction of the developer carrying body with respect to the seal member, and is opposed to outer peripheral surfaces at both ends in the longitudinal direction of the developer carrying body. A developing device comprising: a damming portion for damming the developer leaking from the outer peripheral surfaces of both ends in the longitudinal direction of the agent carrier.   The said damming part is dented in the direction away from the outer peripheral surface of the said developer carrier as compared with the part around the said damming part in the said upstream part. Development device.   3. The developing device according to claim 1, wherein a wall portion protruding toward an outer peripheral surface side of the developer carrying member is provided at an upstream end portion in the rotation direction of the damming portion. .   4. The film member according to claim 3, further comprising a film member that is provided on an end surface of the wall portion on the upstream side in the rotation direction and protrudes toward the outer peripheral surface side of the developer carrier from the wall portion. Development device.   The film member includes an upstream end surface in the rotational direction in the wall portion of the damming portion on one end side in the longitudinal direction and an upstream side in the rotational direction in the wall portion of the damming portion on the other end side in the longitudinal direction. The developing device according to claim 4, wherein the developing device is disposed between the end surface of the developing device.   The end surface on the upstream side in the rotation direction of the wall portion is flush with the end surface on the upstream side in the rotation direction in a portion of the casing that borders the opening. Or the developing device according to 5; A partition wall that partitions the inside of the housing into a first chamber in which the developer carrying member is disposed and a second chamber in which developer for supplying the developer carrying member is stored;
The said housing | casing can be divided | segmented into the 1st frame in which the said partition wall was provided, and the 2nd frame in which the said damming part was provided, The Claim 1 thru | or 6 characterized by the above-mentioned. Development device.   An image forming apparatus comprising the developing device according to claim 1.

Images