JP2006039431A - Developing device, process cartridge, image forming apparatus, and assembling method of developing device - Google Patents

Abstract

A developing device capable of reliably preventing leakage of developer from between a casing and a layer thickness regulating member even when the dimension of the layer thickness regulating member in a direction orthogonal to the longitudinal direction of the developer carrying member is reduced. A process cartridge, an image forming apparatus including such a developing device or a process cartridge, and a method of assembling such a developing device.
In an opening 41 of a housing 36, a plate-like upper mounting portion 47 extending in the longitudinal direction of the opening 41 and having a width in the front-rear direction, and an extending portion 62 of a bending prevention member 58 of a blade unit 40 are provided. And an upper seal 75 for sealing the gap therebetween. Accordingly, the space between the upper mounting portion 47 and the extending portion 62 can be sealed, and the developing cartridge 26 can be reduced in size while preventing the leakage of toner from between them.
[Selection] Figure 8

Description

  The present invention relates to a developing device, a process cartridge, an image forming apparatus including the developing device or the process cartridge, and an assembling method of the developing device.

In an image forming apparatus such as a laser printer, an electrostatic latent image is formed on the surface of a photosensitive drum, and a developer image is formed on the surface of the photosensitive drum by supplying developer from the developing device to the electrostatic latent image. Supported. Then, the developer image is transferred onto the paper, thereby forming an image on the paper.
The developing device regulates a housing having an opening that opens toward the photosensitive drum, a developing roller that carries the developer contained in the housing, and a layer thickness of the developer carried on the developing roller. And a blade for. The developing roller is rotatably supported in a state where a part of the surface is exposed at the opening of the housing. Further, the blade is formed in a thin plate shape extending along the axial direction of the developing roller, the upper end portion thereof is supported by the casing, and the lower end portion thereof is pressed against the surface of the developing roller. The developer in the housing is supplied onto the surface of the developing roller, and passes between the blade and the surface of the developing roller as the developing roller rotates, forming a thin layer with a constant thickness. Is supported on the surface of the substrate. The developer carried on the surface of the developing roller is supplied to the electrostatic latent image formed on the surface of the photosensitive drum when it contacts the surface of the photosensitive drum.

In such a developing device, the developer in the housing enters the back surface of the blade (the surface opposite to the surface facing the developing roller), wraps around the top edge of the blade from the back surface, Leakage may occur from between the housing. Therefore, in a conventional image forming apparatus, a blade back seal member is provided on the back surface of the blade to prevent leakage of the developer due to wraparound from the back surface of the blade (see, for example, Patent Document 1).
JP 2000-75657 A

  However, in recent years, in order to reduce the size of the image forming apparatus, it has been desired to reduce the dimension in the height direction (vertical direction) of the developing device. In order to reduce the height dimension of the developing device, the height dimension of the blade must be reduced, and the height dimension of the blade back seal member must be reduced accordingly. Don't be. However, when the height dimension of the blade back seal member is reduced, the seal width in the height direction on the back surface of the blade is narrowed, the sealing performance is lowered, and the developer leaks due to wraparound from the back surface of the blade. There is a problem that it becomes easy.

Therefore, an object of the present invention is to reduce the dimension of the layer thickness regulating member from between the housing and the layer thickness regulating member even if the dimension in the height direction (the opposite direction of the first wall portion and the developer carrying member) is reduced. Another object of the present invention is to provide a developing device, a process cartridge, and an image forming apparatus including such a developing device or a process cartridge that can reliably prevent the leakage of the developer.
Another object of the present invention is to reduce the size of the layer thickness regulating member between the casing and the layer thickness regulating member even if the dimension in the height direction (the opposite direction of the first wall portion and the developer carrier) is reduced. It is an object of the present invention to provide a developing device assembling method capable of reliably preventing leakage of developer from between.

  In order to achieve the above object, according to the first aspect of the present invention, in the developing device, a housing having a longitudinal opening and a receiving portion that communicates with the opening and contains the developer; A first wall that is provided at one end along the longitudinal direction of the opening, extends along the longitudinal direction, and extends along the direction of communication between the opening and the accommodating portion; and A developer carrier that is disposed along the longitudinal direction of the opening, is rotatably supported by the housing, and carries a developer, and one end thereof is disposed opposite to the first wall portion, and the development is started from the one end. A layer thickness regulating member that extends toward the surface of the developer carrying body, the other end presses the developer carrying body, and regulates the layer thickness of the developer carried on the developer carrying body; Sandwiched between one wall portion and the layer thickness regulating member, the first wall portion and the layer It is characterized in that it comprises a first sealing member for sealing between the regulating member.

According to such a configuration, the developer from between the housing and the layer thickness regulating member is held by the first seal member sandwiched between the first wall portion provided in the housing and the layer thickness regulating member. Leakage can be prevented.
The layer thickness regulating member has one end on the first wall portion side between the first wall portion provided at one end along the longitudinal direction of the opening portion of the housing and the developer carrier disposed in the opening portion. To the developer carrier. That is, the layer thickness regulating member is disposed between the first wall portion and the developer carrier so as to extend in the opposing direction of the first wall portion and the developer carrier. Since the first seal member is sandwiched between one end of the layer thickness regulating member arranged in this way and the first wall portion, in the facing direction of the first wall portion and the developer carrying member, Even if the dimension of the layer thickness regulating member (the dimension in the height direction) is decreased in order to reduce the dimension, it is not necessary to reduce the dimension of the first seal member. As a result, the sealing performance by the first sealing member can be ensured, and the developing device can be downsized while reliably preventing the leakage of the developer from between the housing and the layer thickness regulating member. .

  According to a second aspect of the present invention, in the first aspect of the present invention, the first wall portion is opposed to the layer thickness regulating member and has a width in a direction perpendicular to the opposite direction. The layer thickness regulating member includes a second facing surface facing the first wall portion and having a width in a direction orthogonal to the facing direction, and the first seal member is the first facing surface. And the second facing surface.

According to such a configuration, the first seal member is sandwiched between the first opposing surface and the second opposing surface having a width in a direction orthogonal to the opposing direction of the first wall portion and the layer thickness regulating member. The width can be increased. As a result, the sealing performance by the first seal member can be improved, and the leakage of the developer from between the housing and the layer thickness regulating member can be prevented more reliably.
The invention according to claim 3 is the blade according to claim 2, wherein the layer thickness regulating member is formed in a thin plate shape extending in the longitudinal direction of the opening, and presses the developer carrier. And a first support member that is arranged along one surface of the blade and supports the blade on the first wall portion side, and the first support member includes a contact portion that contacts the blade; And an extended portion extending in the communication direction from an end portion of the contact portion facing the first wall portion, wherein the second facing surface is formed in the extended portion. .

  According to such a configuration, high rigidity can be imparted to the first support member by the contact portion and the extending portion. For this reason, by bringing the contact portion of the first support member into contact with the blade and supporting the blade by the first support member, it is possible to prevent the blade from bending or swelling. As a result, the developer carrier can be pressed with a uniform force by the blade, and a thin layer of developer having a uniform thickness can be carried on the developer carrier. In addition, since the second facing surface is formed in the extended portion, there is no need to separately provide a member for sandwiching the first seal member with the first facing surface of the first wall portion. Reduction can be achieved.

The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the first wall portion is formed integrally with the housing.
According to such a configuration, the number of parts can be reduced, and the configuration can be simplified.
The invention according to claim 5 is the casing according to any one of claims 1 to 4, wherein the casing is orthogonal to the communication direction and extends along the longitudinal direction of the opening. A second wall portion disposed opposite to the layer thickness regulating member, and sandwiched between the second wall portion and the layer thickness regulating member, and the second wall portion and the layer thickness regulating member. And a second seal member for sealing between the two.

According to such a configuration, the leakage of the developer can be prevented by the second seal member even between the second wall portion provided in the housing and the layer thickness regulating member. Therefore, the leakage of the developer from between the housing and the layer thickness regulating member can be prevented more reliably.
The invention according to claim 6 is the invention according to claim 5, wherein the first seal member and the second seal member are integrally formed.

According to such a configuration, the number of parts can be reduced, and the number of steps for attaching the first seal member and the second seal member can be reduced.
The invention according to claim 7 is the invention according to claim 5 or 6, wherein the layer thickness regulating member has a surface on one side opposite to the surface on which the first support member of the blade is provided. A second support member that is in contact with the second wall portion and is spaced apart from the first wall portion, the second seal member being in contact with the second wall portion. Is sandwiched between the second wall portion and the first support member between the first wall portion and the second support member.

  According to such a configuration, the blade can be further reinforced by the second support member disposed on the surface opposite to the surface on which the first support member of the blade is provided, and the bending of the blade can be prevented more reliably. can do. Therefore, the developer carrier can be pressed with a more uniform force by the blade, and as a result, a thin layer of developer having a more uniform thickness can be carried on the developer carrier. Moreover, since the other surface of the second support member contacts the second wall portion and the second seal member is disposed between the first wall portion and the second support member, the second support member and the second wall portion are arranged. The second seal member does not bite between the second support member and the second wall portion, so that a gap can be prevented from being generated, and a reliable seal can be secured.

The invention according to claim 8 is the invention according to any one of claims 5 to 7, wherein the second wall portion is formed integrally with the housing.
According to such a configuration, the number of parts can be reduced, and the configuration can be simplified.
According to a ninth aspect of the present invention, a process cartridge detachable from the image forming apparatus includes the developing device according to any one of the first to eighth aspects.

According to such a configuration, even when the dimension of the layer thickness regulating member in the direction orthogonal to the longitudinal direction of the developer carrying member is reduced, the leakage of the developer from between the housing and the layer thickness regulating member is ensured. Since the developing device that can be prevented is provided, the developing device can be downsized, and the process cartridge can be downsized in response to the downsizing of the developing device.
According to a tenth aspect of the present invention, in the image forming apparatus, the developing device according to any one of the first to eighth aspects or the process cartridge according to the ninth aspect is provided.

  According to such a configuration, even when the dimension of the layer thickness regulating member in the direction orthogonal to the longitudinal direction of the developer carrying member is reduced, the leakage of the developer from between the housing and the layer thickness regulating member is ensured. Since the developing device or the process cartridge that can be prevented is provided, the process cartridge can be downsized, and the image forming apparatus can be downsized in response to the downsizing of the process cartridge.

  According to an eleventh aspect of the present invention, there is provided a longitudinal opening, a housing that communicates with the opening and contains a developer, and a longitudinal direction of the opening in the opening. A developer carrying member that is rotatably supported by the housing and carries the developer, and a layer thickness of the developer carried on the developer carrying member by pressing the developer carrying member And a layer thickness regulating member for regulating the developing device, wherein the developing device is provided at one end along the longitudinal direction of the opening and extends along the longitudinal direction, and A first wall extending along the direction of communication between the opening and the housing; and the first wall and the layer thickness regulating member sandwiched between the first wall and the layer thickness regulating member. A first seal member for sealing between and a direction orthogonal to the communication direction, A second wall portion provided in the housing and arranged to face the layer thickness regulating member so as to extend along a longitudinal direction of the opening; the second wall portion and the layer thickness regulating member; And a second seal member for sealing between the second wall portion and the layer thickness regulating member, the layer thickness regulating member extending in the longitudinal direction of the opening One end is disposed opposite the first wall portion, the other end is disposed along a surface of the blade that presses the developer carrier, and is disposed on the first wall portion side. A first support member that supports the blade, and one surface is in contact with a surface of the blade opposite to the surface on which the first support member is provided, and the other surface opposite to the one surface is the second wall. A second support member that is in contact with a portion and is spaced apart from the first wall portion, After the first seal member and the second seal member are disposed in contact with the first wall portion and the second wall portion, respectively, the layer thickness regulating member is placed on the first support member and the first seal member is placed on the first seal member. It is characterized by being attached to the housing from the direction of pressing against the first wall and pressing the second seal member against the second wall with the first support member.

  According to such a method, the layer thickness regulating member is configured such that the first support member presses the first seal member against the first wall portion, and the first support member presses the second seal member against the second wall portion. Is attached to the housing, so that the other surface of the second support member is brought into contact with the second wall portion, and at the same time, the second seal member can be disposed between the second support member and the first wall portion. Therefore, it is possible to prevent the second seal member from being caught between the second support member and the second wall portion.

According to the first aspect of the present invention, even if the dimension of the layer thickness regulating member in the height direction (opposite direction between the first wall portion and the developer carrying member) is reduced, the sealing performance by the first seal member is maintained. Thus, the developing device can be downsized while reliably preventing the leakage of the developer from between the casing and the layer thickness regulating member.
According to the second aspect of the present invention, it is possible to improve the sealing performance by the first sealing member, and more reliably prevent the leakage of the developer from between the casing and the layer thickness regulating member. it can.

According to the third aspect of the present invention, a thin layer of developer having a uniform thickness can be carried on the developer carrying member. In addition, the number of parts can be reduced.
According to the invention described in claim 4, the number of parts can be reduced, and the configuration can be simplified.
According to the fifth aspect of the present invention, the leakage of the developer from between the housing and the layer thickness regulating member can be prevented more reliably.

According to the invention described in claim 6, the number of parts can be reduced, and the number of steps for attaching the first seal member and the second seal member can be reduced.
According to the seventh aspect of the invention, a thin layer of developer having a more uniform thickness can be carried on the developer carrying member. Moreover, it can prevent that a clearance gap produces between a 2nd support member and a 2nd wall part, and can ensure a reliable seal | sticker.

According to the invention described in claim 8, the number of parts can be reduced, and the configuration can be simplified.
According to the ninth aspect of the invention, the process cartridge can be downsized.
According to the invention described in claim 10, it is possible to reduce the size of the image forming apparatus.
According to the eleventh aspect of the present invention, it is possible to prevent the second seal member from being caught between the second support member and the second wall portion.

FIG. 1 is a cross-sectional side view of a main part showing an embodiment of a laser printer as an image forming apparatus of the present invention. In FIG. 1, a laser printer 1 includes a feeder unit 4 for feeding a sheet 3 and an image forming unit 5 for forming an image on the fed sheet 3 in a main body casing 2. .
An attachment / detachment opening 6 for attaching / detaching a process cartridge 18 to be described later is formed on one side wall of the main casing 2, and a front cover 7 for opening / closing the attachment / detachment opening 6 is provided. The front cover 7 is rotatably supported by a cover shaft (not shown) inserted through the lower end portion thereof. Thus, when the front cover 7 is closed around the cover axis, the attachment / detachment opening 6 is closed by the front cover 7, and when the front cover 7 is opened with the cover axis as a fulcrum (tilted), the attachment / detachment opening 6 is opened, The process cartridge 18 can be attached to and detached from the main casing 2 through the attachment / detachment opening 6. In addition, an operation panel (not shown) including operation keys and LED display units is embedded in the front cover 7.

Hereinafter, in the laser printer 1, the side on which the front cover 7 is provided is referred to as “front side”, and the opposite side is referred to as “rear side”.
The feeder unit 4 includes a paper feed tray 8 that is detachably attached to the bottom of the main casing 2, a paper feed roller 9 and a paper feed pad 10 that are provided above the front end of the paper feed tray 8, A pickup roller 11 provided on the rear side of the roller 9, a pinch roller 12 disposed oppositely on the lower front side of the paper feed roller 9, and a registration roller 13 provided on the upper rear side of the paper feed roller 9 are provided.

Inside the paper feed tray 8 is provided a paper pressing plate 14 on which the paper 3 can be placed in a stack. The paper pressing plate 14 is supported at the rear end so as to be swingable, so that the front end is movable in the vertical direction.
A lever 15 for lifting the front end portion of the paper pressing plate 14 upward is provided at the front end portion of the paper feed tray 8. The lever 15 is formed in a substantially L-shaped cross section so as to go from the front side to the lower side of the paper pressing plate 14, and its upper end is attached to a lever shaft 16 provided at the front end of the paper feed tray 8. The rear end portion is in contact with the front end portion of the lower surface of the paper pressing plate 14. Accordingly, when a clockwise rotational driving force in the drawing is input to the lever shaft 16, the lever 15 rotates about the lever shaft 16, and the rear end portion of the lever 15 lifts the front end portion of the paper pressing plate 14.

When the front end of the sheet pressing plate 14 is lifted, the uppermost sheet 3 on the sheet pressing plate 14 is pressed by the pickup roller 11, and the sheet feeding roller 9 and the sheet feeding pad 10 are rotated by the rotation of the pickup roller 11. Conveyance is started in between.
On the other hand, when the paper feed tray 8 is detached from the main casing 2, the front end portion of the paper pressing plate 14 moves downward due to its own weight, and is in a state along the bottom surface of the paper feed tray 8. In this state, the sheets 3 can be stacked on the sheet pressing plate 14.

The sheet 3 sent out between the sheet feeding roller 9 and the sheet feeding pad 10 by the pickup roller 11 is sandwiched between the sheet feeding roller 9 and the sheet feeding pad 10 by the rotation of the sheet feeding roller 9. Sometimes, each sheet is reliably fed and fed. The fed paper 3 passes between the paper feed roller 9 and the pinch roller 12 and is conveyed to the registration roller 13.
The registration roller 13 is composed of a pair of rollers facing each other, and after the registration of the sheet 3, the transfer position of the image forming unit 5 (a nip position between a photosensitive drum 28 and a transfer roller 30 described later, The toner image on the photosensitive drum 28 is conveyed toward the transfer position of the paper 3.

The image forming unit 5 includes a scanner unit 17, a process cartridge 18, a fixing unit 19, and the like.
The scanner unit 17 is provided in the upper part of the main casing 2 and includes a laser light source (not shown), a polygon mirror 20 that is rotationally driven, an fθ lens 21, a reflecting mirror 22, a lens 23, a reflecting mirror 24, and the like. The laser beam based on the image data emitted from the laser light source is deflected by the polygon mirror 20 as shown by a chain line, passes through the fθ lens 21, then the optical path is turned back by the reflecting mirror 22, and further passes through the lens 23. After that, the optical path is further bent downward by the reflecting mirror 24, so that the surface of a photosensitive drum 28 (to be described later) of the process cartridge 18 is irradiated at high speed.

The process cartridge 18 is detachably attached to the main body casing 2 below the scanner unit 17. The process cartridge 18 includes a drum cartridge 25 and a developing cartridge 26 as a developing device that is detachably attached to the drum cartridge 25.
Each of the drum cartridges 25 extends in the front-rear direction, and is between a pair of side plates 27 arranged to face each other in a direction orthogonal to the front-rear direction (a direction perpendicular to the paper surface in FIG. 1; hereinafter, simply referred to as “width direction”). A developing cartridge 26 is mounted on the front side, and a photosensitive drum 28, a scorotron charger 29, a transfer roller 30, and a cleaning brush 31 are provided on the rear side.

  The photosensitive drum 28 includes a cylindrical drum body 32 formed by a positively chargeable photosensitive layer whose outermost layer is made of polycarbonate or the like, and a metal extending along the longitudinal direction of the drum body 32 at the axis of the drum body 32. And a drum shaft 33 made of steel. The drum shaft 33 is non-rotatably supported on both side plates 27 of the drum cartridge 25, and the drum main body 32 is rotatably supported on the drum shaft 33, so that the photosensitive drum 28 is disposed between the both side plates 27. The shaft 33 is provided to be rotatable.

  The scorotron charger 29 is disposed oppositely and spaced apart from the rear side of the photosensitive drum 28 so as not to contact the photosensitive drum 28. The scorotron charger 29 is a positively-charged scorotron charger that generates corona discharge from a charging wire such as tungsten, so that the surface of the photosensitive drum 28 can be uniformly charged positively. Is provided.

  The transfer roller 30 is rotatably supported by both side plates 27 of the drum cartridge 25, and is disposed so as to face and contact the photosensitive drum 28 in the vertical direction so as to form a nip with the photosensitive drum 28. Yes. The transfer roller 30 is configured by covering a metal roller shaft 34 with a roller 35 made of a conductive rubber material. A transfer bias is applied to the transfer roller 30 during transfer.

The cleaning brush 31 is disposed behind the photosensitive drum 28 so that the tip of the brush is in contact with the surface of the drum body 32 of the photosensitive drum 28.
As shown in FIG. 2, the developing cartridge 26 includes a housing 36, a toner storage chamber 37 as a storage portion, a supply roller 38, a developing roller 39 as a developer carrier, and a layer thickness regulation in the housing 36. And a blade unit 40 as a member.

The housing 36 is formed in a box shape having a longitudinal opening 41 at the rear end.
Specifically, as shown in FIGS. 2 and 3, the housing 36 includes an upper wall 42 and a lower wall 43 that face each other in the vertical direction, and a width direction between the upper wall 42 and the lower wall 43. A pair of side walls 44 provided so as to be closed from both sides, and a front wall 79 provided so as to close between the upper wall 42 and the lower wall 43 from the front side are provided.

  As shown in FIG. 2, the upper wall 42 is provided with a partition plate 45 that extends in the middle in the front-rear direction and extends toward the lower wall 43 from a portion closer to the rear side. The partition plate 45 partitions the internal space of the housing 36, and the front internal space is partitioned as a toner storage chamber 37. A blade attachment member 46 for attaching the blade unit 40 is provided at the rear end portion of the upper wall 42. The blade attachment member 46, the lower wall 43, and a pair of side walls 44 extend in the width direction. A longitudinal opening 41 is defined. A direction in which the toner storage portion 37 and the opening 41 communicate with each other is referred to as a communication direction. That is, in this embodiment, the communication direction and the front-rear direction match.

  The blade mounting member 46 has an L-shaped side cross section, faces the lower wall 43, extends in the width direction, and has an upper mounting portion 47 as a plate-like first wall portion having a width in the front-rear direction, and the upper mounting portion. A front mounting portion 48 is integrally provided as a second wall portion that is bent downward from the front end portion of the portion 47, extends in the width direction, and has a lattice-like recess formed in a rear view. The blade attachment member 46 may be formed separately from the upper wall 42 and may be fixed to the upper wall 42, or may be formed integrally with the upper wall 42. If the blade mounting member 46 is formed integrally with the upper wall 42, the number of parts of the laser printer 1 can be reduced, and the configuration can be simplified.

  The front end portion of the lower wall 43 extends obliquely upward on the front side and is connected to the front wall 79 so as to be continuous. A film placement portion 121 extending along the axial direction of the developing roller 39 is formed on the rear upper surface of the lower wall 43. In the film placement portion 121, a lower film 122 made of polyethylene terephthalate and rubbed uniformly along the axial direction on the peripheral surface of the roller 56 of the developing roller 39 is placed. The lower film 122 is rubbed uniformly along the axial direction on the peripheral surface of the roller 56 of the developing roller 39 above the lower wall 43, so that the toner is between the lower wall 43 and the developing roller 39. Leakage can be prevented. Furthermore, the front wall 79 extends forward from a connection portion with the upper wall 42 and is further folded downward to hold the developing cartridge 26 when being attached to or detached from the drum cartridge 25. Is provided.

  In the toner storage chamber 37, positively charged non-magnetic one-component toner is stored as a developer. Examples of the toner include polymerizable monomers such as styrene monomers such as styrene, and acrylic monomers such as acrylic acid, alkyl (C1 to C4) acrylate, and alkyl (C1 to C4) methacrylate. Polymerized toners obtained by copolymerization by a known polymerization method such as suspension polymerization are used. Such a polymerized toner has a spherical shape, has extremely good fluidity, and can achieve high-quality image formation.

Such a toner is blended with a colorant such as carbon black, wax, and the like, and an external additive such as silica is added to improve fluidity. The particle diameter is about 6 to 10 μm.
An agitator 50 for agitating the toner in the toner storage chamber 37 is provided in the toner storage chamber 37. The agitator 50 is supported by a rotation shaft 51 extending in the width direction at the center of the toner storage chamber 37, and the toner in the toner storage chamber 37 is rotated by rotating the agitator 50 about the rotation shaft 51. Is agitated and discharged toward the rear side from the communication port 52 between the partition plate 45 and the lower wall 43.

The supply roller 38 is disposed obliquely below the rear side of the communication port 52 and is rotatably supported between the pair of side walls 44 of the housing 36. The supply roller 38 is configured by covering a metal roller shaft 53 with a roller 54 made of a conductive foam material.
The developing roller 39 is disposed behind the supply roller 38 along the width direction in the opening 41 and is rotatably supported between a pair of side walls 44 of the housing 36. Further, the developing roller 39 is disposed so that a part of the surface of the developing roller 39 protrudes rearward from the opening 41 of the housing 36 and is exposed, and the developing roller 26 is attached to the drum cartridge 25 and the photosensitive drum 28. Contact in the front-rear direction. The developing roller 39 is configured by covering a metal roller shaft 55 with a roller 56 made of a conductive rubber material. In the roller 56 of the developing roller 39, the surface of a roller layer made of conductive urethane rubber or silicone rubber containing carbon fine particles is coated with a coating layer of urethane rubber or silicone rubber containing fluorine. Further, the roller 56 of the developing roller 39 is disposed in contact with the roller 54 of the supply roller 38 so as to be compressed with each other.

  As shown in FIG. 4, FIG. 5, FIG. 6, or FIG. 7, the blade unit 40 includes a leaf spring member 57 as a blade and a bending prevention member 58 as a first support member for supporting the leaf spring member 57. And a reinforcing plate 59 as a second support member. As will be described in detail later, in the blade unit 40, the reinforcing plate 59 is attached to the front mounting portion 48 with respect to the blade mounting member 46 in a state where the leaf spring member 57 is sandwiched between the bending preventing member 58 and the reinforcing plate 59. It is attached so that it may contact and oppose.

  The leaf spring member 57 is made of a thin metal leaf spring material, and is formed in a rectangular shape having substantially the same width as the axial width of the roller 56 of the developing roller 39. In a state where the blade unit 40 is attached to the blade attachment member 46, the upper end portion of the leaf spring member 57 is sandwiched between the bending prevention member 58 and the reinforcing plate 59 and extends in the axial direction (longitudinal direction) of the developing roller 39. Be placed. Further, a pressing member 60 having a substantially rectangular cross section made of insulating silicone rubber is provided at the lower end portion of the leaf spring member 57 along the lower end edge.

  The bending preventing member 58 has an L-shaped side section, extends along the longitudinal direction of the leaf spring member 57, and is disposed in contact with the surface of the leaf spring member 57. More specifically, the bend prevention member 58 includes a rectangular plate-like contact portion 61 that contacts the surface of the leaf spring member 57 and the upper end of the contact portion 61 in a state where the blade unit 40 is attached to the blade attachment member 46. The extending portion 62 extending rearward from the edge and the two gripping portions 63 extending downward from the rear end portion of the extending portion 62 are integrally provided. Accordingly, the bending prevention member 58 has high rigidity, supports the leaf spring member 57, and prevents the leaf spring member 57 from bending such as bending and swell.

  The extending portion 62 is provided between the end extending portion 64 extending at a first width from both ends in the longitudinal direction of the upper end edge of the contact portion 61, and the upper end edge of the contact portion 61. A central extension portion 65 extending from the central portion in the longitudinal direction with a second width larger than the first width. In other words, the extending portion 62 extends rearward from the entire longitudinal direction of the upper end edge of the contact portion 61 and has notches 66 at both longitudinal ends.

The two gripping portions 63 extend from both longitudinal ends of the central extension portion 65 obliquely rearward and downward with respect to the central extension portion 65, and are formed in a rectangular shape in the rear view.
The reinforcing plate 59 is made of an elongated rectangular metal plate, and is disposed in contact with the back surface of the leaf spring member 57 along the longitudinal direction of the leaf spring member 57. The reinforcing plate 59 is formed to be slightly narrower than the width (width in the vertical direction) of the contact portion 61 of the bending prevention member 58, and the leaf spring member 57 is interposed between the reinforcement plate 59 and the contact portion 61 of the bending prevention member 58. The leaf spring member 57 is further reinforced by supporting in the sandwiched state.

  The blade unit 40 is arranged on the surface of the leaf spring member 57 with the contact portion 61 of the bending preventing member 58 in contact with the upper end portion thereof, and on the back surface of the leaf spring member 57, the contact portion 61 and the leaf spring member are arranged. The reinforcing plate 59 is disposed in contact with the plate 57 at the opposite positions, and the bending preventing member 59 is inserted into the bending preventing member 59 and the insertion holes (not shown) formed at both longitudinal ends of the reinforcing plate 59. The screws 94 are respectively inserted from the 58 side and assembled by screwing the screws 94 into the screw grooves 80 formed at both ends of the reinforcing plate 59. In this assembly, the notches 66 are formed at both ends in the longitudinal direction of the extending portion 62 of the bending prevention member 58, so that the screw 94 can be easily inserted even from the bending prevention member 58 side. Can do.

In the blade unit 40 assembled in this way, the lower end surface of the contact portion 61 and the lower end surface of the reinforcing plate 59 are aligned substantially in the vertical direction. In a state where the unit 40 is attached to the blade attachment member 46, a gap is formed between the upper end surface of the reinforcing plate 59 and the lower surface 73 of the upper attachment portion 47.
In the blade unit 40 assembled in this way, as shown in FIG. 2, the extended portion 62 of the bending preventing member 58 is opposed to the upper mounting portion 47 via an upper seal 75 described later with respect to the blade mounting member 46. The reinforcing plate 59 is attached so as to be opposed to the front attachment portion 48. In this attachment, the grasping portion 63 can be grasped from the notch portion 66 and can be aligned with the blade attachment portion 46, so that the blade unit 40 can be easily attached to the blade attachment member 46. . In addition, in this attachment, in the contact part 61 of the bending prevention member 58, the leaf | plate spring member 57, and the longitudinal direction both ends (both ends outside the longitudinal direction both ends to which each screw 94 is screwed) Then, a screw (not shown) is inserted into a mounting hole 81 (see FIGS. 4 and 5) penetrating in the thickness direction, and the screw is screwed to the blade mounting member 46, thereby the blade unit 40. Is fixed to the blade mounting member 46.

In a state where the blade unit 40 is attached to the blade attachment member 46, the lower end portion of the leaf spring member 57 faces the roller 56 of the developing roller 39 from the front side, and the pressing member 60 is the elastic force of the leaf spring member 57. Is pressed against the roller 56.
In FIG. 2, the toner discharged from the communication port 52 to the inner space on the rear side of the housing 36 by the rotation of the agitator 50 is supplied onto the roller 56 of the developing roller 39 by the rotation of the supply roller 38. At this time, the roller 54 of the supply roller 38 and the roller 56 of the developing roller 39 are positively frictionally charged. The toner supplied onto the roller 56 of the developing roller 39 enters between the pressing member 60 of the blade unit 40 and the roller 56 of the developing roller 39 with the rotation of the developing roller 39, and here, the toner is further sufficiently rubbed. It is charged to form a thin layer having a constant thickness and is carried on the roller 56 of the developing roller 39.

On the other hand, as shown in FIG. 1, the surface of the photosensitive drum 28 is uniformly positively charged by a scorotron charger 29 and then exposed by high-speed scanning of a laser beam from the scanner unit 17, and is statically based on image data. An electrostatic latent image is formed.
Next, the electrostatic latent image formed on the surface of the photosensitive drum 28 when the toner carried on the developing roller 39 and positively charged comes into contact with the photosensitive drum 28 by rotation of the developing roller 39. That is, the surface of the photosensitive drum 28 that is uniformly positively charged is supplied to an exposed portion that is exposed to a laser beam and the potential is lowered, and is selectively carried to be visualized. Thus, a toner image is formed by reversal development.

Thereafter, the photosensitive drum 28 and the transfer roller 30 are rotationally driven so as to sandwich and convey the sheet 3 therebetween, and the sheet 3 is conveyed between the photosensitive drum 28 and the transfer roller 30. A toner image carried on the surface of the photosensitive drum 28 is transferred onto the paper 3.
It should be noted that the paper dust adhering to the surface of the photosensitive drum 28 by contact with the paper 3 after the transfer is when the surface of the photosensitive drum 28 faces the brush of the conductive brush 31 as the photosensitive drum 28 rotates. , Removed by that brush.

The fixing unit 19 is provided on the rear side of the process cartridge 18, and includes a fixing frame 67, and a heating roller 68 and a pressing roller 69 in the fixing frame 67.
The heating roller 68 includes a metal base tube and a halogen lamp for heating in the metal base tube, and is rotationally driven by power input from a motor (not shown).
The pressing roller 69 is disposed below the heating roller 68 so as to press the heating roller 68. The pressing roller 69 is configured by covering a metal roller shaft with a roller made of a rubber material, and is driven according to the rotational driving of the heating roller 68.

  In the fixing unit 19, the toner transferred onto the sheet 3 is thermally fixed while the sheet 3 passes between the heating roller 68 and the pressing roller 69. The sheet 3 on which the toner is fixed is conveyed to a sheet discharge path 70 extending in the vertical direction toward the upper surface of the main body casing 2. The sheet 3 conveyed to the sheet discharge path 70 is discharged onto a sheet discharge tray 72 formed on the upper surface of the main casing 2 by a sheet discharge roller 71 provided at the upper end of the sheet 3.

In the developing cartridge 26, as shown in FIG. 8, the lower surface 73 as the first opposing surface of the upper mounting portion 47 of the blade mounting member 46 and the second opposing surface of the extending portion 62 of the bending preventing member 58. An upper seal 75 serving as a first seal member for sealing between the upper surface 74 and the upper surface 74 is sandwiched.
The upper seal 75 is made of a sponge material such as urethane foam and is formed in an elongated rectangular plate shape. The upper seal 75 has a width in the longitudinal direction set equal to the width in the longitudinal direction of the extending portion 62 of the bending preventing member 58, and the width in the front-rear direction is slightly smaller than the first width of the end extending portion 64. As shown in FIG. 9 with hatching, it is arranged along the front end edge of each end extending portion 64 over the entire longitudinal direction of the extending portion 62, and is attached by a double-sided tape or the like. Yes. Further, the upper seal 75 is provided with the lower surface 73 of the upper attachment portion 47 and the upper surface 74 of the extension portion 62 when the blade unit 40 is attached to the blade attachment member 46 before the blade unit 40 is attached to the blade attachment member 46. It has a thickness larger than the distance between them. As a result, when the blade unit 40 is attached to the blade attachment member 46, the upper seal 75 is compressed inward in the opposing direction between the upper attachment portion 47 and the extension portion 62, and the upper attachment portion 47 and the extension portion 62 are compressed. Can be elastically pressed, and the space between the upper mounting portion 47 and the extending portion 62 can be reliably sealed over the entire length of the extending portion 62. Therefore, it is possible to prevent the toner that enters the back surface of the leaf spring member 57 and goes around from the back surface to the upper end portion of the leaf spring member 57 from leaking out between the upper mounting portion 47 and the extending portion 62.

  Further, since the upper seal 75 is sandwiched between the upper mounting portion 47 and the extending portion 62, the height direction of the developing unit 26 (vertical direction) is reduced in order to reduce the height direction of the blade unit 40. Even if the size is reduced, the width in the longitudinal direction of the upper seal 75 can be sufficiently secured. Therefore, sufficient sealing performance by the upper seal 75 can be ensured, and the developing cartridge 26 can be reduced in size while reliably preventing toner leakage between the upper mounting portion 47 and the extending portion 62. it can.

Furthermore, since the lower surface 73 of the upper mounting portion 47 and the upper surface 74 of the extending portion 62 have a width in the front-rear direction, the width in the front-rear direction of the upper seal 75 can be set large. The toner leakage from between the upper mounting portion 47 and the extending portion 62 can be prevented more reliably.
The bending preventing member 58 can impart a relatively high rigidity to the bending preventing member 58 by allowing the contact portion 61 and the extending portion 62 to continue in a bent shape. Therefore, the contact portion 61 of the bending prevention member 58 is brought into contact with the back surface (rear surface) of the leaf spring member 57, and the leaf spring member 57 is supported by the bending prevention member 58. Curvature such as swell can be prevented. As a result, the pressing member 60 can be pressed against the roller 56 of the developing roller 39 with a uniform force by the elastic force of the leaf spring member 57, and a thin layer of toner having a uniform thickness is carried on the surface of the roller 56. be able to. Further, since the upper surface 74 of the extended portion 62 also serves as a clamping surface of the upper seal 75, there is no need to separately provide a member for clamping the upper seal 75 with the upper mounting portion 47 of the blade mounting member 46. The number of points can be reduced.

Further, since the process cartridge 18 includes the developing cartridge 26 that can reliably prevent toner leakage even when the height of the blade unit 40 is reduced, the process cartridge 18 can be reduced in size. The laser printer 1 can be downsized in response to the downsizing of the process cartridge 18.
FIG. 10 is a cross-sectional side view of a main part showing another embodiment of the developing cartridge 26. In addition, about the part corresponding to each said part, the same referential mark is attached | subjected in FIG. 10, and the description is abbreviate | omitted below.

In the developing cartridge 26, an upper seal 76 sandwiched between the upper mounting portion 47 of the blade mounting member 46 and the extending portion 62 of the bending preventing member 58 is provided between the upper mounting portion 47 and the extending portion 62. It is formed so as to go around between the front mounting portion 48 and the contact portion 61 of the bending preventing member 58.
The upper seal 76 is made of a sponge material such as urethane foam. As shown in FIG. 11, the upper seal 76 is disposed on the upper surface 74 of the extending portion 62 and on the back surface side of the leaf spring member 57. A seal front portion 78 as a second seal member is integrally provided, and a seal upper portion 77 is adhered to the upper surface 74 and a seal front portion 78 is adhered to the contact portion 61 by a double-sided tape or the like. .

  Similar to the upper seal 75 described above, the seal upper portion 77 is disposed along the front end edge of the end extending portion 64 over the entire longitudinal direction of the extending portion 62, and before the blade unit 40 is attached to the blade mounting member 46. In this state, the blade unit 40 has a thickness larger than the distance (see FIG. 10) between the upper attachment portion 47 and the extension portion 62 when the blade unit 40 is attached to the blade attachment member 46.

  The seal front part 78 extends continuously from the seal upper part 77 to a position in contact with the upper end surface of the reinforcing plate 59. This seal front part 78 is the distance between the leaf spring member 57 and the front attachment part 48 when the blade unit 40 is attached to the blade attachment member 46 in a state before the blade unit 40 is attached to the blade attachment member 46. That is, the reinforcing plate 59 has a thickness larger than the thickness in the front-rear direction.

  The blade unit 40 then presses the seal upper portion 77 against the upper mounting portion 47 by the extended portion 62 of the bending preventing member 58 against the blade mounting member 46, and the reinforcing plate 59 contacts the front mounting portion 48. The seal front portion 78 is attached to the front attachment portion 48 by the contact portion 61 of the bending prevention member 58. As a result, the seal upper portion 77 is compressed in the opposing direction of the upper mounting portion 47 and the extending portion 62, and elastically presses the upper mounting portion 47 and the extending portion 62, respectively. Further, the seal front portion 78 is compressed in the opposing direction between the front mounting portion 48 and the contact portion 61 of the bending preventing member 58, and elastically presses the front mounting portion 48 and the contact portion 61, respectively. Therefore, the upper portion 77 and the extended portion 62 can be reliably sealed by the seal upper portion 77, and the front portion 78 and the contact portion 61 of the bending preventing member 58 can be sealed by the seal front portion 78. Can be reliably sealed. As a result, the toner in the housing 36 can be prevented from entering between the front mounting portion 48 and the contact portion 61 of the bending preventing member 58, and the toner from between the upper mounting portion 47 and the extending portion 62 can be prevented. Can be prevented more reliably.

Further, since the seal upper portion 77 and the seal front portion 78 are integrally formed, the number of parts can be reduced as compared with the case where they are formed separately, and the number of steps for the attachment can be reduced. Can be reduced.
Further, since the reinforcing plate 59 is in contact with the front mounting portion 48 and the seal front portion 78 is arranged in the gap between the lower surface 73 of the upper mounting portion 47 and the upper end surface of the reinforcing plate 59, the reinforcing plate 59 and the front mounting portion are attached. The seal front portion 78 does not bite between the portion 48 and the gap between the reinforcing plate 59 and the front mounting portion 48 can be prevented, and a reliable seal can be secured.

In this embodiment, the upper seal 76 is adhered to the blade unit 40. However, as shown in FIG. 12, the upper seal 76 is adhered to the blade mounting member 46 with a double-sided tape or the like, and the upper seal 76 is adhered. The blade unit 40 may be attached to the blade attachment member 46 thus formed.
In this case, as shown in FIG. 13A, after the upper seal 76 is adhered to the blade mounting member 46, the blade unit 40 is directed from the rear lower side of the upper seal 76 toward the front upper side, and the bending preventing member. The seal upper portion 77 is pressed against the upper mounting portion 47 of the blade mounting member 46 by the extending portion 62 of the blade 58, and the seal front portion 78 is pressed against the front mounting portion 48 of the blade mounting member 46 by the contact portion 61 of the bending preventing member 58. Install as follows. If attached in this way, as shown in FIG. 13 (b), the reinforcing plate 59 is securely attached to the front mounting portion 48 without causing the seal front portion 78 to bite between the reinforcing plate 59 and the front mounting portion 48. The seal front portion 78 can be reliably disposed between the lower surface 73 of the upper mounting portion 47 and the upper end surface of the reinforcing plate 59.

1 is a cross-sectional side view of an essential part showing an embodiment of a laser printer as an image forming apparatus of the present invention. FIG. 2 is a side sectional view of the developing cartridge shown in FIG. 1. FIG. 3 is a rear view of a housing of the developing cartridge shown in FIG. 2. FIG. 3 is a rear view of the blade unit shown in FIG. 2. FIG. 3 is a front view of the blade unit shown in FIG. 2. FIG. 3 is a plan view of the blade unit shown in FIG. 2. FIG. 3 is a side view of the blade unit shown in FIG. 2. FIG. 3 is a side sectional view showing a configuration in the vicinity of a blade unit in the developing cartridge shown in FIG. 2. It is a top view which shows the sticking position of the upper seal in the blade unit shown in FIG. FIG. 6 is a side cross-sectional view showing a main part of another embodiment of the developing cartridge shown in FIG. 2. It is a side view which shows the state by which the upper seal was affixed on the blade unit shown in FIG. FIG. 11 is a perspective view showing a state where an upper seal is attached to the housing of the developing cartridge shown in FIG. 10. FIG. 11 is a side sectional view for explaining a method of attaching the blade unit to the housing of the developing cartridge shown in FIG. 10.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser printer 18 Process cartridge 26 Development cartridge 36 Case 37 Toner storage chamber 39 Developing roller 40 Blade unit 41 Opening part 47 Upper attachment part 48 Front attachment part 57 Leaf spring member 58 Bending prevention member 59 Reinforcement plate 62 Extension part 73 Lower surface 74 Upper surface 75 Upper seal 76 Upper seal 77 Upper seal 78 Front seal

Claims (11)

A housing having a longitudinal opening, and an accommodating portion that communicates with the opening and accommodates the developer;
A first wall that is provided at one end along the longitudinal direction of the opening, extends along the longitudinal direction, and extends along the direction of communication between the opening and the housing;
A developer carrier that is disposed along the longitudinal direction of the opening in the opening and is rotatably supported by the housing, and carries a developer;
One end is disposed opposite to the first wall portion, extends from the one end toward the surface of the developer carrying member, and the other end presses the developer carrying member and is carried on the developer carrying member. A layer thickness regulating member for regulating the layer thickness of the agent;
A first seal member is provided between the first wall portion and the layer thickness regulating member and is sealed between the first wall portion and the layer thickness regulating member. A developing device. The first wall portion includes a first facing surface that faces the layer thickness regulating member and has a width in a direction orthogonal to the facing direction.
The layer thickness regulating member includes a second facing surface that faces the first wall and has a width in a direction orthogonal to the facing direction.
The developing device according to claim 1, wherein the first seal member is sandwiched between the first facing surface and the second facing surface. The layer thickness regulating member is formed in a thin plate shape extending in the longitudinal direction of the opening, and is disposed along a surface of the blade that presses the developer carrying member, and on the first wall side. And a first support member for supporting the blade,
The first support member includes a contact portion that contacts the blade, and an extending portion that extends in the communication direction from an end portion of the contact portion that faces the first wall portion,
The developing device according to claim 2, wherein the second facing surface is formed in the extending portion.   The developing device according to claim 1, wherein the first wall portion is formed integrally with the housing. A second wall provided in the housing and disposed opposite the layer thickness regulating member so as to be orthogonal to the communication direction and extend along a longitudinal direction of the opening;
And a second seal member that is sandwiched between the second wall portion and the layer thickness regulating member and seals between the second wall portion and the layer thickness regulating member. The developing device according to any one of claims 1 to 4.   The developing device according to claim 5, wherein the first seal member and the second seal member are integrally formed. The layer thickness regulating member has one surface in contact with the surface of the blade opposite to the surface on which the first support member is provided, and the other surface opposite to the one surface in contact with the second wall portion. And a second support member disposed at a distance from the first wall portion,
The second seal member is sandwiched between the second wall portion and the first support member between the first wall portion and the second support member. The developing device according to 5 or 6.   The developing device according to claim 5, wherein the second wall portion is formed integrally with the housing. In a process cartridge that is detachable from an image forming apparatus,
A process cartridge comprising the developing device according to claim 1.   An image forming apparatus comprising the developing device according to claim 1 or the process cartridge according to claim 9. A housing having a longitudinal opening, a housing that communicates with the opening, and that accommodates the developer, and is disposed along the longitudinal direction of the opening in the opening and is rotatable on the housing A developer carrier that is supported and carries the developer; and a layer thickness regulating member that regulates the layer thickness of the developer carried on the developer carrier by pressing the developer carrier. A developing device assembly method comprising:
The developing device is provided at one end along the longitudinal direction of the opening, extends along the longitudinal direction, and extends along the communication direction between the opening and the accommodating portion; A first seal member that is sandwiched between the first wall portion and the layer thickness regulating member and seals between the first wall portion and the layer thickness regulating member; and orthogonal to the communication direction; And the 2nd wall part provided in the said housing | casing so that it may extend along the longitudinal direction of the said opening part, and arrange | positions facing the said layer thickness control member, The said 2nd wall part and the said layer thickness control member And a second seal member for sealing between the second wall portion and the layer thickness regulating member,
The layer thickness regulating member is formed in a thin plate shape extending in the longitudinal direction of the opening, one end of the layer thickness regulating member is disposed to face the first wall portion, and the other end of the blade pressing the developer carrier, A first support member disposed along one surface and supporting the blade on the first wall side, and one surface is in contact with the surface of the blade opposite to the surface on which the first support member is provided A second support member that is disposed on the other surface opposite to the one surface in contact with the second wall portion and spaced from the first wall portion,
After placing the first seal member and the second seal member in contact with the first wall portion and the second wall portion, respectively,
From the direction in which the layer thickness regulating member is pressed against the first wall by the first support member and the second seal member is pressed against the second wall by the first support member. A method of assembling a developing device, wherein the developing device is attached to the housing.

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