JP2006039314A - Developing roller cover and developing cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing roller cover capable of preventing the surface of a developing roller from being damaged at the time of attaching the developing roller cover to a developing cartridge, and to provide the developing cartridge equipped with the developing roller cover. <P>SOLUTION: In the developing roller cover 89 attached to the developing cartridge 26 in a state where the developing cartridge 26 is separated from a main body casing 2, a cover part 90 opposed to the developing roller 39 at the attaching time is formed in shape extended in the shaft direction of the developing roller 39 and symmetric in a direction orthogonal to the shaft direction, and a pair of locking parts 91 and 92 locked on a housing 36 are arranged at positions mutually symmetric in a longitudinal direction with respect to the center in the longitudinal direction of the cover part 90. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

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

2. Description of the Related Art Conventionally, image forming apparatuses such as laser printers are detachably equipped with a developing cartridge for supplying toner to the surface of a photosensitive drum.
The developing cartridge includes a housing that accommodates toner and a developing roller that carries the toner in the housing. The housing has a longitudinal opening that opens toward the photosensitive drum, and the developing roller is rotatably supported in the opening with a part of the surface exposed. The toner in the housing is carried on the surface of the developing roller, and is supplied to the electrostatic latent image formed on the surface of the photosensitive drum when it contacts the surface of the photosensitive drum as the developing roller rotates. Is done. As a result, the electrostatic latent image on the surface of the photosensitive drum is developed into a toner image, and then the toner image is transferred to the paper, thereby forming an image on the paper.

When the toner in the casing runs out, such a developing cartridge is removed from the image forming apparatus and replaced with a new developing cartridge filled with toner. The developing cartridge removed from the image forming apparatus is collected by the manufacturer and reused (recycled).
However, when the developing cartridge is detached from the image forming apparatus, a part of the surface of the developing roller is exposed from the housing, and thus the exposed portion may be damaged during transportation of the developing cartridge. Therefore, a cover member for protecting the developing roller is attached to such a developing cartridge when it is detached from the image forming apparatus.

Such a cover member includes, for example, a developing roller protective cover disposed to face the developing roller, a cover handle formed at the center of the upper end of the developing roller protective cover, and ribs formed at both ends of the lower end. The thing is proposed (for example, refer patent document 1). In this cover member, the cover member is gripped, the ribs are hooked on the lower end portion of the developing cartridge, and the cover member is rotated with the hooked portion of each rib and the developing cartridge as a fulcrum. Can be attached to or removed from the developing cartridge.
JP 2003-195730 A

However, in the configuration described in Patent Document 1, when the cover member is mounted on the developing cartridge, if the cover member is mounted upside down, the ribs and both ends in the longitudinal direction of the cover member contact the surface of the developing roller. In some cases, the surface of the developing roller may be damaged.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a developing roller cover that can prevent the surface of the developing roller from being damaged when mounted on the developing cartridge, and a developing cartridge including the developing roller cover.

  In order to achieve the above object, an invention according to claim 1 includes: a housing having a longitudinal opening; and a developing roller provided in the housing and disposed so as to be partially exposed to the opening. A developing roller cover that is formed to be attachable to and detachable from the developing cartridge, covers the opening in the mounted state, and protects the surface of the developing roller, and faces the surface of the developing roller in the mounted state. And a cover portion extending in the axial direction of the developing roller and having a symmetrical shape in a direction perpendicular to the axial direction of the developing roller, and a position symmetrical to each other in the longitudinal direction with respect to the longitudinal center of the cover portion. And a pair of locking portions that are locked to the housing in the mounted state.

  According to such a configuration, the cover portion has a symmetrical shape in a direction orthogonal to the axial direction of the developing roller, and the pair of locking portions are symmetrical to each other in the longitudinal direction with respect to the longitudinal center of the cover portion. Since the developing roller cover is in a state where one end portion in a direction orthogonal to the longitudinal direction of the cover portion (axial direction of the developing roller) is directed either above or below the opening of the housing. Even when the cover is mounted, it is possible to prevent the both ends in the longitudinal direction of the cover portion and the respective locking portions from coming into contact with the surface of the developing roller. Therefore, when the developing roller cover is mounted, the developing roller can be protected while preventing the surface of the developing roller from being damaged by the contact of each part such as the cover part and the locking part.

The invention according to claim 2 is the invention according to claim 1, wherein the cover part is formed along a rectangular plate-like main body part and each edge in a direction orthogonal to the longitudinal direction of the main body part. And a pair of abutting portions that protrude from the main body and abut against the housing in the mounted state.
According to such a configuration, the pair of abutting portions are arranged at positions symmetrical with respect to a direction orthogonal to the axial direction of the developing roller. Therefore, even if the developing roller cover is mounted in a state where one end portion in a direction orthogonal to the longitudinal direction of the cover portion is directed above or below the opening of the housing, each contact portion contacts the housing. Therefore, it is possible to prevent each contact portion from contacting the surface of the developing roller. As a result, when the developing roller cover is mounted, the respective contact portions are brought into contact with the housing, and the developing roller can be reliably protected by the developing roller cover. Can be prevented from being damaged.

  According to a third aspect of the present invention, in the second aspect of the present invention, the contact portions extend in the longitudinal direction of the main body, and face each other with an interval in a direction orthogonal to the longitudinal direction. An outer rib and an inner rib, and a plurality of abutting ribs arranged between the outer rib and the inner rib and spaced apart in the longitudinal direction of the main body. Yes.

According to such a structure, it can prevent that a housing | casing fits between an outer side rib and an inner side rib by several contact ribs. Therefore, each contact part can be reliably contact | abutted with respect to a housing | casing.
According to a fourth aspect of the present invention, in the invention according to the second or third aspect, the housing has a first contact on both sides in a direction perpendicular to the longitudinal direction of the opening with respect to the opening. A contact portion and a second contacted portion are provided, and one of the pair of contact portions is in contact with the first contacted portion and the other is in contact with the second contacted portion. It is characterized by.

  According to such a configuration, even if the developing roller cover is mounted with one end portion in a direction orthogonal to the longitudinal direction of the cover portion facing upward or downward of the opening of the housing, a pair of contacts Since the portion abuts on the first abutted portion and the second abutted portion, each abutting portion can be prevented from abutting on the surface of the developing roller. Therefore, it is possible to prevent the surface of the developing roller from being damaged by the contact of the contact portion when the developing roller cover is mounted.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the developing cartridge is provided with a locking projection that protrudes outward in the axial direction of the developing roller from the housing. The locking portion has a locking hole through which the locking projection can be inserted, and in the mounted state, the locking projection is inserted into the locking hole, and the locking projection is inserted into the locking projection. It is characterized by being locked.

  According to such a configuration, the locking protrusion is provided on the developing cartridge, and the locking hole into which the locking protrusion can be inserted is formed in the locking portion. If the locking projection is inserted into the locking hole, the locking portion can be locked to the locking projection, and the developing roller cover can be locked to the housing. Therefore, the developing roller cover can be reliably locked to the housing with a simple configuration.

According to a sixth aspect of the invention, in the fifth aspect of the invention, the locking projection is an end portion of the shaft of the developing roller protruding from the housing.
According to such a configuration, since the end portion of the shaft of the developing roller also serves as a locking projection, the number of parts can be reduced and the configuration can be simplified.
Further, the invention according to claim 7 is the invention according to claim 5 or 6, wherein at least one of the pair of locking portions has the locking hole detached from the locking protrusion in the mounted state. It is characterized by being provided with an operating portion that is formed so as to be elastically deformable in the direction to be operated and that is operated during the elastic deformation.

According to such a configuration, when the operation portion is operated, at least one of the locking portions can be elastically deformed in a direction in which the locking holes are detached from the locking projections. Therefore, the locking portion can be easily locked / detached with respect to the locking protrusion. As a result, it is possible to reduce time and labor when the developing roller cover is attached / detached to / from the developing cartridge.
The invention according to claim 8 is the invention according to claim 7, wherein both of the pair of locking portions are in a direction in which the locking holes are detached from the locking projections in the mounted state. It is formed to be elastically deformable, and has an operation portion that is operated at the time of the elastic deformation.

  According to such a configuration, both the pair of locking portions are formed so as to be elastically deformable, and each locking portion is provided with an operation portion. For this reason, the developing roller cover can be attached / detached to / from the developing cartridge by simultaneously operating the operating portions of both locking portions to lock / release the locking holes of the locking portions with respect to the locking projections. Can be achieved. In addition, after inserting the locking projection into the locking hole of one locking portion, locking the locking hole to the locking projection, operating the operating portion of the other locking portion, the other By locking the locking hole of the locking portion with respect to the locking projection, the developing roller cover can be attached to the developing cartridge, or only the operating portion of one locking portion can be operated to After releasing the locking hole of the locking part from the locking protrusion, the developing roller cover is slid and the locking hole of the other locking part is released from the locking protrusion, so that the developing roller cover with respect to the developing cartridge is removed. A withdrawal can also be achieved. In addition, since it has a symmetrical shape also in the longitudinal direction of the cover portion, one end of the developing roller cover in the direction orthogonal to the longitudinal direction of the cover portion is directed either above or below the opening of the housing. It can be worn even in the state. As a result, it is possible to further improve the workability when the developing roller cover is attached to and detached from the developing cartridge.

The invention described in claim 9 is characterized in that, in the invention described in claim 8, a display for recognizing the operation unit is added.
According to such a configuration, when both the locking portions of the pair of locking portions are provided with operation portions, which operation portion is used when the developing roller cover is attached to or detached from the developing cartridge. Can be easily recognized.

  The invention according to claim 10 is the invention according to any one of claims 1 to 9, wherein the casing is provided with side walls on both sides in the longitudinal direction of the opening. It is characterized by comprising a pair of restricting portions that extend from both sides of the cover portion in the longitudinal direction in a direction opposite to the casing and abut against the side walls from the outside in the longitudinal direction of the cover portion.

  According to such a configuration, in a state where the developing roller cover is attached to the developing cartridge, the pair of restricting portions are opposed to the side walls provided on both sides in the longitudinal direction of the opening from the outside in the longitudinal direction of the cover portion. Each abuts. Therefore, since the developing roller cover can be positioned in the longitudinal direction of the cover portion by each restricting portion, the surface of the developing roller can be more reliably protected by the cover portion. In addition, when the developing roller cover is mounted, it is possible to prevent each regulating portion from coming into contact with the surface of the developing roller.

An eleventh aspect of the invention is characterized in that, in the tenth aspect of the invention, each regulating portion covers an exposed portion of the developing roller from the outside in the axial direction in the mounted state.
According to such a configuration, the exposed portions of the developing roller can be covered and protected from the outside in the axial direction by the restricting portions. Therefore, it is possible to more reliably prevent the exposed portion of the developing roller from being damaged.

The invention according to claim 12 is the invention according to claim 10 or 11, wherein each of the restricting portions is disposed on the inner side in the longitudinal direction of the cover portion with respect to each of the locking portions. It is characterized by.
According to such a configuration, when the locking portion is locked to the locking protrusion protruding from the housing to the outside in the axial direction of the developing roller, each regulating portion prevents the locking portion from being locked. Can be prevented. Therefore, the workability of attaching and detaching the developing roller cover to the developing cartridge can be further improved.

The invention described in claim 13 is characterized in that, in the invention described in claim 12, each restricting portion is formed with a receiving portion for receiving the locking projection in the mounted state.
According to such a structure, since the latching protrusion can be received by the receiving part of each restricting part, each restricting part can be reliably brought into contact with each side wall. Thereby, reliable locking of the locking portion with respect to the locking protrusion can be achieved.

According to a fourteenth aspect of the present invention, in the developing cartridge, a casing having a longitudinal opening, a developing roller provided in the casing and disposed so as to be partially exposed in the opening, The developing roller cover according to any one of Items 1 to 13 is provided.
According to such a configuration, since the developing roller cover is provided that can prevent each part such as the cover part and the locking part from coming into contact with the developing roller when the developing cartridge is attached, the developing roller cover is attached. Sometimes, the developing roller cover can prevent the surface of the developing roller from being damaged.

The invention according to claim 15 is the invention according to claim 14, wherein the housing is mounted on both sides in a direction perpendicular to the longitudinal direction of the opening with respect to the opening. And the developing roller cover is provided with a first contacted portion and a second contacted portion.
According to such a configuration, even if the developing roller cover is mounted with one end portion in a direction orthogonal to the longitudinal direction of the cover portion facing upward or downward of the opening of the housing, a pair of contacts Since the portion abuts on the first abutted portion and the second abutted portion, each abutting portion can be prevented from abutting on the surface of the developing roller. For this reason, when the developing roller cover is mounted, the abutting portions are brought into contact with the housing, and the developing roller can be reliably protected by the developing roller cover. Injury can be prevented.

The invention according to claim 16 is the invention according to claim 14 or 15, wherein the housing projects from the housing outward in the axial direction of the developing roller, and in the mounted state, the developing roller cover Each of the locking portions is provided with a locking projection for locking.
According to such a configuration, the locking protrusion is provided on the developing cartridge, and the locking hole into which the locking protrusion can be inserted is formed in the locking portion. If the locking projection is inserted into the locking hole, the locking portion can be locked to the locking projection, and the developing roller cover can be locked to the housing. Therefore, the developing roller cover can be reliably locked to the housing with a simple configuration.

According to a seventeenth aspect of the invention, in the invention of the sixteenth aspect, the locking protrusion is an end portion of the shaft of the developing roller protruding from the housing.
According to such a configuration, the end portion of the shaft of the developing roller also serves as the locking projection, so that the configuration can be simplified.

According to the first aspect of the present invention, when the developing roller cover is mounted, the developing roller can be protected while preventing the surface of the developing roller from being damaged by the contact of each portion such as the cover portion and the locking portion. it can.
According to the second aspect of the present invention, when the developing roller cover is mounted, the abutting portions are brought into contact with the housing, and the developing roller can be reliably protected by the developing roller cover. It is possible to prevent the surface of the developing roller from being damaged by the contact.

According to invention of Claim 3, each contact part can be reliably contact | abutted with respect to a housing | casing.
According to the fourth aspect of the present invention, it is possible to prevent the surface of the developing roller from being damaged by the contact of the contact portion when the developing roller cover is mounted.
According to the fifth aspect of the present invention, the developing roller cover can be reliably locked to the housing with a simple configuration.

According to the sixth aspect of the present invention, since the end portion of the shaft of the developing roller also serves as the locking projection, the number of parts can be reduced and the configuration can be simplified.
According to the seventh aspect of the present invention, it is possible to reduce time and labor when the developing roller cover is attached / detached to / from the developing cartridge.
According to the eighth aspect of the present invention, it is possible to further improve the workability when the developing roller cover is attached to and detached from the developing cartridge.

According to the ninth aspect of the present invention, it is possible to easily recognize which operation unit should be operated when the developing roller cover is attached to or detached from the developing cartridge.
According to the invention described in claim 10, the surface of the developing roller can be more reliably protected by the cover portion.
According to the eleventh aspect of the present invention, it is possible to more reliably prevent the exposed portion of the developing roller from being damaged.

According to the twelfth aspect of the present invention, it is possible to further improve the workability of attaching and detaching the developing roller cover to the developing cartridge.
According to the invention of claim 13, reliable locking of the locking portion with respect to the locking projection can be achieved.
According to the fourteenth aspect of the present invention, it is possible to prevent the surface of the developing roller from being damaged by the developing roller cover when the developing roller cover is mounted.

According to the fifteenth aspect of the present invention, when the developing roller cover is attached, the abutting portions are brought into contact with the housing so that the developing roller can be reliably protected by the developing roller cover. It is possible to prevent the surface of the developing roller from being damaged by the contact.
According to the sixteenth aspect of the present invention, the developing roller cover can be reliably locked to the housing with a simple configuration.

  According to the seventeenth aspect of the present invention, since the end of the shaft of the developing roller also serves as the locking projection, the number of parts can be reduced and the configuration can be simplified.

(1) Overall Configuration of Image Forming Apparatus FIGS. 1 and 2 are cross-sectional side views of a main part showing an embodiment of a laser printer provided with the developing cartridge of the present invention. The laser printer 1 includes a feeder unit 4 for feeding paper 3 and an image forming unit 5 for forming an image on the fed paper 3 in a main body casing 2.

In the main casing 2, an attachment / detachment opening 6 for attaching / detaching a process cartridge 18 described later is formed on one side wall, 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. As a result, when the front cover 7 is closed around the cover shaft, the detachable opening 6 is closed by the front cover 7 as shown in FIG. 1, and when the front cover 7 is opened with the cover shaft as a fulcrum (when tilted). As shown in FIG. 2, the attachment / detachment opening 6 is opened, and the process cartridge 18 can be attached to / detached from the main casing 2 through the attachment / detachment opening 6.

Hereinafter, in the laser printer 1 and the process cartridge 18 (including a developing cartridge 26 described later), 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 broken 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 casing 2 below the scanner unit 17 (see FIG. 2). The process cartridge 18 includes a drum cartridge 25 and a developing cartridge 26 that is detachably attached to the drum cartridge 25. The developing cartridge 26 can be attached to and detached from the main body casing 2 integrally with the drum cartridge 25, and only the developing cartridge 26 is attached to the main body casing 2 with the drum cartridge 25 mounted on the main body casing 2. It can also be attached to and detached from.

The drum cartridge 25 extends in the front-rear direction, and between the pair of side plates 27 arranged to face each other in a direction perpendicular to the front-rear direction and the vertical direction (hereinafter simply referred to as “width direction”), A photosensitive drum 28, a scorotron charger 29, a transfer roller 30, and a cleaning brush 31 are provided.
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 on both side plates 27 of the drum cartridge 25, contacts the photosensitive drum 28 from the lower side in the vertical direction, and forms a nip with the photosensitive drum 28. Has been placed. 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.
The developing cartridge 26 is detachably mounted on the front side between the side plates 27 of the drum cartridge 25. FIG. 3 is a side sectional view of the developing cartridge 26. As shown in the figure, the developing cartridge 26 includes a housing 36, and a supply roller 38, a developing roller 39, and a blade unit 40 provided in the housing 36.

The housing 36 is composed of a lower frame 41 and an upper frame 42, has a box shape having an opening 43 opened toward the rear side, and a toner storage chamber 44 and a developing chamber 45 are defined therein. .
The lower frame 41 includes a left side wall 46 and a right side wall 47 (see FIG. 4) as side walls opposed to each other with a gap in the width direction, a lower wall 48 that connects the left side wall 46 and the right side wall 47, and An upper wall 49 and an upper front wall 50 provided at the front edge of the upper wall 49 are integrally provided.

  The lower wall 48 has a plate-like shape extending in the front-rear direction and the width direction, is inclined upward from the rear side toward the front side, and includes a rear lower wall portion 51 for defining the developing chamber 45, and a rear lower wall. A front lower wall portion 52 having a substantially arcuate cross-section along a rotational track of an agitator 65, which will be described later, is provided integrally with the front end edge of the portion 51. Further, a lower partition 53 that protrudes upward in a substantially triangular shape is formed along the width direction at the boundary between the rear lower wall 51 and the front lower wall 52. The lower wall 48 is provided so as to be sandwiched between the left side wall 46 and the right side wall 47.

FIG. 4 is a plan view of the developing cartridge 26. As shown in the figure, the upper wall 49 has a flat plate shape and is provided between the upper end edges of the left side wall 46 and the right side wall 47. As shown in FIG. 3, an upper surface opening 54 (see FIG. 3) having a substantially rectangular shape in plan view on which the upper frame 42 is covered is formed at a position corresponding to the toner storage chamber 37 on the upper wall 49. .
A blade attachment portion 55 having an L-shaped side section is formed at the rear end portion of the upper wall 49 along the width direction. Specifically, the blade attachment portion 55 is opposed to the rear lower wall portion 51 of the lower wall 48 via the developing roller 72, and includes an upper attachment portion 56 that extends rearward from the rear edge of the upper surface opening 54. And a front mounting portion 57 extending downward from the front end portion of the upper mounting portion 56.

In addition, the front end edge of the lower wall 48 is connected to the front end portion of the upper surface opening 54 in the upper wall 49, and the front side from the connection portion is further extended forward and extends in the front-rear direction and the width direction. An upper wall extension 58 is provided. The upper surface of the upper wall extension 58 is formed in a planar shape.
The upper front wall 50 has a plate shape and is formed so as to be bent in a substantially right angle direction downward from the front edge of the upper wall extension 58. The upper front wall 50 extends partway in the vertical direction of the housing 36, and its front surface is formed in a planar shape.

  The left side wall 46 and the right side wall 47 are formed in a plate shape extending in the vertical direction and the front-rear direction, and an upper wall 49 is installed at the upper edge of the left side wall 46 and the right side wall 47. . The rear end edges of the left side wall 46 and the right side wall 47 extend to the rear end edge of the rear lower wall portion 51 of the lower wall 48 and the rear end edge of the upper wall 49. Further, the front end edges of the left side wall 46 and the right side wall 47 extend to the upper front wall 50 and are connected to the upper front wall 50. Further, a front lower wall portion 52 is connected to the left side wall 46 and the right side wall 47 in the front-rear direction, and an extended portion extending from the connection portion to the upper front wall 50 is shown in FIG. Thus, the left side wall extension 59 and the right side wall extension 60 are provided.

The left side wall 46 is provided with a gear mechanism 61 for inputting a mechanical driving force to the supply roller 38, the developing roller 39, and the agitator 65.
As shown in FIG. 4, the upper frame 42 has a substantially rectangular flat plate shape, closes the upper surface opening 54 of the lower frame 41, and is welded to the lower frame 41. On the lower surface of the upper frame 42, as shown in FIG. 3, an upper partition plate 62 is formed along the width direction so as to face the lower partition portion 53 of the lower wall 48 and project downward. . The upper partition plate 62 and the lower partition portion 53 are spaced apart in the vertical direction, and the gap is formed as a toner discharge port 63.

In the housing 36, the internal space behind the upper partition plate 62 and the lower partition portion 53 is defined as the developing chamber 45, and the internal space ahead of the upper partition plate 62 and the lower partition portion 53 is the toner storage. It is defined as a chamber 44.
In the toner storage chamber 44, 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.
Further, in the toner storage chamber 44, a toner detection window 64 for allowing light from a toner empty sensor (not shown) made of a light sensor provided in the main body casing 2 to pass through on the left side wall 46 and the right side wall 47. , Provided at opposite positions in the width direction.

  Further, an agitator 65 for stirring the toner in the toner storage chamber 44 is provided in the toner storage chamber 44. The agitator 65 is provided in the toner storage chamber 44 at a central portion in a side view, and is rotatably supported by the left side wall 46 and the right side wall 47, and an agitator support portion 67 extending from the rotary shaft 66 in the radial direction. And a flexible film 68 attached to the agitator support portion 67.

The supply roller 38 is disposed on the lower front side in the developing chamber 45 and is rotatably supported by the left side wall 46 and the right side wall 47. The supply roller 38 includes a metal supply roller shaft 69 and a sponge roller 70 made of a conductive foam material that covers the periphery of the supply roller shaft 69.
The developing roller 39 is disposed below the rear side in the developing chamber 45, is in pressure contact with the supply roller 38, and is provided so that the rear portion is partially exposed rearward from the opening 43 of the housing 36. ing. The developing roller 39 includes a developing roller shaft 71 as a metal shaft and a rubber roller 72 made of a conductive rubber material that covers the periphery of the developing roller shaft 71. More specifically, both end portions in the axial direction of the developing roller shaft 71 are rotatably supported by the left side wall 46 and the right side wall 47. The rubber roller 72 is made of conductive urethane rubber or silicone rubber containing carbon fine particles, and the surface thereof is covered with fluorine-containing urethane rubber or silicone rubber. As shown in FIG. 4, shaft end portions on both sides as locking protrusions of the developing roller shaft 71 are provided so as to protrude from the left side wall 46 and the right side wall 47.

  As shown in FIG. 3, the blade unit 40 includes a blade 73, a bending prevention member 74 and a reinforcing plate 75 for supporting the blade 73. The blade unit 40 is attached to the blade attachment portion 55 so that the reinforcement plate 75 faces and contacts the front attachment portion 57 in a state where the blade 73 is sandwiched between the bending prevention member 74 and the reinforcement plate 75. ing.

  The blade 73 is made of a thin plate spring material made of metal, and is formed in a rectangular shape having substantially the same width as the axial width of the rubber roller 72 of the developing roller 39. The upper end portion of the blade 73 is sandwiched between the bending prevention member 74 and the reinforcing plate 75. A pressing rubber member 76 having a rectangular cross section made of insulating silicone rubber is provided at the lower end of the blade 73 so as to extend in the longitudinal direction of the blade 73. In a state where the blade unit 40 is attached to the blade attachment portion 55, the lower end portion of the blade 73 faces the rubber roller 72 of the developing roller 39 from the front side, and the pressing rubber member 76 is rubber roller 72 by the elastic force of the blade 73. Pressure contacted.

  The bending prevention member 74 has an L-shaped side section, extends in the longitudinal direction of the blade 73, and is disposed to face the upper end portion of the surface of the blade 73. This bend prevention member 74 extends in a rearward direction from the upper edge of the contact portion 77 when the blade unit 40 is attached to the blade attachment portion 55 and the rectangular plate-like contact portion 77 that contacts the surface of the blade 73. The part 78 and the grip part 79 as two 1st contact parts extended below from the rear end part (free end part of the extension direction) of the extension part 78 are integrally provided.

As shown in FIG. 4, the extending portion 78 is provided between an end extending portion 80 extending at a first width from both longitudinal ends of the upper end edge of the contact portion 77, and the both end extending portions 80. And a central extending portion 81 extending from the central portion in the longitudinal direction of the upper end edge of the contact portion 77 with a second width larger than the first width.
FIG. 5 is a perspective view showing a state when the developing cartridge 26 is detached. As shown in FIG. 5, the two gripping portions 79 are respectively connected to the central extension portion from both longitudinal ends of the central extension portion 81. It extends obliquely rearward and downward with respect to 81, and is formed in a rectangular shape in rear view. Each grip 79 includes a rear end edge 82 as a second contact portion of the rear lower wall 51 of the lower wall 48 in the vertical direction with the blade unit 40 attached to the blade attachment 55. Opposed and has both a function as a member to be gripped when the blade unit 40 is assembled and a function of abutting and supporting a developing roller cover 89 described later.

  The reinforcing plate 75 is made of an elongated rectangular metal plate and extends along the longitudinal direction of the blade 73. The reinforcing plate 75 faces the contact portion 77 of the bending prevention member 74 across the blade 73 on the back surface of the blade 73, and its lower end surface is flush with the lower end surface of the contact portion 77 in the vertical direction. It is arranged in the position. The reinforcing plate 75 further supports the blade 73 by supporting the upper end portion of the blade 73 in a sandwiched state between the reinforcing plate 75 and the bending preventing member 74.

  By rotating the agitator 65, the toner in the toner storage chamber 44 is agitated and discharged from the toner discharge port 63 toward the developing chamber 45. The toner discharged into the developing chamber 45 is supplied onto the rubber roller 72 of the developing roller 39 by the rotation of the supplying roller 38. At this time, the toner is positively transferred between the sponge roller 70 of the supplying roller 38 and the rubber roller 72 of the developing roller 39. Is triboelectrically charged. The toner supplied onto the rubber roller 72 of the developing roller 39 enters between the pressing rubber member 76 of the blade unit 40 and the rubber roller 72 of the developing roller 39 as the developing roller 39 rotates, and is thin with a certain thickness. A layer is carried on the rubber roller 72 of the developing roller 39.

On the other hand, referring to 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.
Note that the paper dust adhering to the surface of the photosensitive drum 28 by contact with the paper 3 after the transfer, when the surface of the photosensitive drum 28 faces the brush of the cleaning brush 31 as the photosensitive drum 28 rotates, Removed by the brush.

The fixing unit 19 is provided on the rear side of the process cartridge 18, and includes a fixing frame 83, and a heating roller 84 and a pressing roller 85 in the fixing frame 83.
The heating roller 84 includes a metal base tube and a halogen lamp for heating in the metal base tube, and is rotationally driven by input of power from a motor (not shown).
The pressing roller 85 is disposed below the heating roller 84 so as to press the heating roller 84. The pressing roller 85 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 84.

  In the fixing unit 19, the toner transferred onto the paper 3 is thermally fixed while the paper 3 passes between the heating roller 84 and the pressing roller 85. The sheet 3 on which the toner is fixed is conveyed to a sheet discharge path 86 that extends in the vertical direction toward the upper surface of the main casing 2. The sheet 3 conveyed to the sheet discharge path 86 is discharged onto a sheet discharge tray 88 formed on the upper surface of the main body casing 2 by a sheet discharge roller 87 provided on the upper side.

As shown in FIG. 5, since the developing roller 39 is provided so that the rubber roller 72 is partially exposed rearward from the opening 43 of the housing 36, only the developing cartridge 26 is detached from the main body casing 2. In this state, the rubber roller 72 of the developing roller 39 may be damaged. Therefore, when only the developing cartridge 26 is detached from the main casing 2, the developing roller cover 89 is attached to the developing cartridge 26 so as to cover the opening 43 of the housing 36 as shown in FIG. 6. FIG. 6 is a perspective view showing a state in which the developing roller cover 89 is attached to the developing cartridge 26.
(2) Configuration of Developing Roller Cover 89 FIG. 7 is a perspective view of the developing roller cover 89. As shown in the figure, the developing roller cover 89 is formed of a resin material, and integrally includes a cover portion 90, a pair of locking portions 91 and 92, and a pair of restricting portions 93. As a resin material, it is preferable to use inexpensive and recyclable PP (manufactured by Sumitomo Chemical Co., Ltd .: Sumitomo Nobrene AH561 (trade name), Mitsui Chemicals, Inc .: Mitsui Polypro J225T / B229T (trade name)). For example, the developing roller cover 89 can be formed by injection molding using the PP.

  The cover 90 faces the surface of the developing roller 39 and extends in the axial direction of the developing roller 39 when the developing roller cover 89 is mounted on the developing cartridge 26 (hereinafter simply referred to as “mounted state”). It has a symmetrical shape in the direction orthogonal to the axial direction (up and down direction in the mounted state). More specifically, the cover portion 90 includes a rectangular plate-shaped main body portion 94 and a pair of contact portions 95 formed along each end edge in a direction orthogonal to the longitudinal direction of the main body portion 94. It has.

  Each contact portion 95 is disposed at a position symmetrical with respect to the developing roller shaft 71 of the developing roller 39 in a direction orthogonal to the axial direction of the developing roller shaft 71 in the mounted state. Each contact portion 95 rises perpendicularly from the main body portion 94 at each end edge in a direction orthogonal to the longitudinal direction of the main body portion 94 and extends in the longitudinal direction of the main body portion 94. It rises in a direction (that is, a direction perpendicular to the longitudinal direction of the main body portion 94) and is spaced from each outer rib 96, and is opposed to each other in the longitudinal direction of each outer rib 96 and the main body portion 94. Between the inner rib 97 and the outer rib 96 and the inner rib 97 along the direction orthogonal to the longitudinal direction of the main body portion 94, and is arranged in parallel with a gap in the longitudinal direction of the main body portion 94. And a plurality of abutting ribs 98 arranged. The outer rib 96, the inner rib 97, and the plurality of contact ribs 98 protrude from the main body portion 94 at the same height (projection amount).

The pair of locking portions 91 and 92 are disposed to face each other at positions symmetrical to each other in the longitudinal direction with respect to the longitudinal center of the cover portion 90.
One locking portion 91 extends from one end in the longitudinal direction of the main body portion 94 toward the outer side in the longitudinal direction and extends in the direction perpendicular to the longitudinal direction of the main body portion 94 with an interval therebetween. An extension portion 99, an elastic deformation portion 100 extending from the free end portion of each locking extension portion 99 in the same direction as the protruding direction of the contact portion 95, and a lock for connecting the free end portions of each elastic deformation portion 100 The connection part 101 is provided integrally. Each of the elastic deformation portions 100 and the locking connection portions 101 has a U shape when viewed from the outside in the longitudinal direction of the main body portion 94. A locking hole 102 through which the shaft end portion of the developing roller shaft 71 protruding from the left side wall 46 or the right side wall 47 can be inserted is formed.

  FIG. 8 is a plan view of the developing roller cover 89, and the other engaging portion 92 is directed outward in the longitudinal direction from the other end portion in the longitudinal direction of the main body portion 94 as shown in FIGS. Two locking extension portions 103 extending at intervals in a direction perpendicular to the longitudinal direction of the main body portion 94, and the protrusions of the contact portions 95 from the free end portions of the locking extension portions 103. The elastic deformation portion 104 that extends in the same direction as the direction, the locking connection portion 105 that connects the free ends of each elastic deformation portion 104, and the operation portion 106 that extends obliquely outward from the locking connection portion 105 are integrally provided. ing. Each elastic deformation portion 104 and the locking connection portion 105 are U-shaped when viewed from the outside in the longitudinal direction of the main body portion 94, and the left side wall of the housing 36 is interposed between the elastic deformation portions 104. 46 or a locking hole 107 through which the shaft end of the developing roller shaft 71 protruding from the right side wall 47 can be inserted.

  Each restricting portion 93 is formed in a substantially rectangular plate shape extending from each longitudinal edge of the main body portion 94 in the same direction as the protruding direction of the abutting portion 95, and is opposed to the pair of locking portions 91, 92. In the direction (longitudinal direction of the main body portion 94)), they are arranged to face each other (in the opposite direction). Each regulating portion 93 comes into contact with the left side wall 46 and the right side wall 47 of the housing 36 from the outside in the longitudinal direction of the cover portion 90 in the mounted state. In addition, a bearing recess 108 as a receiving portion for receiving the shaft end portion of the developing roller shaft 71 in the mounted state is formed in the tip portion of each restricting portion 93 so as to be recessed in a semicircular shape from the tip edge. Yes.

  The developing roller cover 89 is attached to the developing cartridge 26 as follows. That is, when the developing roller cover 89 is attached to the developing cartridge 26, as shown in FIGS. 5 and 6, first, with respect to the shaft end portion of the developing roller shaft 71 protruding from the left side wall 46 of the housing 36. One locking portion 91 is brought close to the outside in the axial direction, and the left end of the developing roller shaft 71 is inserted into the locking hole 102 formed in the locking portion 91, so that one of the locking portions 91 is inserted. The stop 91 is locked to the left end of the developing roller shaft 71. At the same time, one restricting portion 93 is brought into contact with the left side wall 46 of the housing 36 from the outside in the longitudinal direction of the cover portion 90. Next, while pulling the operation portion 106 of the other locking portion 92 toward the outside in the longitudinal direction of the cover portion 90 and elastically deforming each elastic deformation portion 104 of the other locking portion 92 so as to open outward in the longitudinal direction, The cover 90 is rotated around one locking portion 91 so as to approach the surface of the developing roller 39 (rubber roller 72), and the locking hole 107 of the other locking portion 92 is moved to the right side wall of the housing 36. The developing roller shaft 71 protruding from the right side is opposed to the right shaft end portion. Thereafter, when the pulling of the operation portion 106 is released, as shown in FIG. 9, each elastic deformation portion 104 is orthogonal to each locking extension portion 103 by the restoring force of each elastic deformation portion 104 of the other locking portion 92. Returning to this state, the right shaft end portion of the developing roller shaft 71 is inserted into the locking hole 107, and the other locking portion 92 is locked to the right shaft end portion of the developing roller shaft 71. Thereby, the mounting of the developing roller cover 89 is achieved. FIG. 9 is a bottom view of the developing cartridge 26 to which the developing roller cover 89 is attached.

  FIG. 10 is a side sectional view of the developing cartridge 26 with the developing roller cover 89 attached thereto. When the developing roller cover 89 is attached, as shown in FIG. 40, the other (lower) contact portion 95 contacts the rear end edge portion 82 of the rear lower wall portion 51 of the housing 36. Then, the cover portion 90 faces the surface of the developing roller 39, and the cover portion 90 covers the opening 43 of the housing 36 so as to be closed. For this reason, the developing roller 39 can be protected by the cover 90, and the rubber roller 72 of the developing roller 39 can be prevented from being damaged.

  Further, each restricting portion 93 comes into contact with the left side wall 46 and the right side wall 47 of the housing 36 from the outside in the longitudinal direction of the cover portion 90. Therefore, the developing roller cover 89 can be positioned in the longitudinal direction of the cover portion 90 by the restricting portions 93, so that the developing roller 39 can be more reliably protected by the cover portion 90. Further, since the restricting portions 93 are disposed outside the opening, it is possible to prevent the restricting portions 93 from coming into contact with the surface of the rubber roller 72 of the developing roller 39 when the developing roller cover 89 is attached.

In addition, each regulating portion 93 can protect the exposed portion of the rubber roller 72 of the developing roller 39 from the outside in the axial direction. Therefore, it is possible to more reliably prevent the exposed portion of the rubber roller 72 of the developing roller 39 from being damaged, and to prevent dust from entering.
In addition, since each restricting portion 93 is disposed inside the engaging portions 91 and 92 in the opposite direction, when the engaging portions 91 and 92 are engaged with the end portions of the developing roller shaft 71, It is possible to prevent the restricting portions 93 from hindering the locking portions 91 and 92 from being locked. Therefore, it is possible to improve the detachability of the developing roller cover 89 with respect to the developing cartridge 26.

  Further, since the bearing recesses 108 are formed in the restricting portions 93, the shaft end portions of the restricting portions 93 and the developing roller shaft 71 can be received by the bearing recesses 108. Therefore, each regulating portion 93 can be reliably brought into contact with the left side wall 46 and the right side wall 47 while preventing each regulating portion 93 and each shaft end portion of the developing roller shaft 71 from interfering with each other. Can do. Accordingly, it is possible to achieve reliable locking of the locking portions 91 and 92 with respect to the end portions of the developing roller shaft 71.

  In addition, the pair of contact portions 95 are disposed at positions symmetrical to the developing roller shaft 71 in a direction orthogonal to the axial direction in the mounted state, and the pair of locking portions 91 and 92 are Since the cover 90 is disposed opposite to the longitudinal center of the cover 90 in a longitudinally symmetrical position, even if the developing roller cover 89 is mounted upside down from the state shown in FIG. It is possible to prevent the portion 95 from coming into contact with the surface of the rubber roller 72 of the developing roller 39.

  That is, one locking portion 91 is locked to the right shaft end portion of the developing roller shaft 71 protruding from the right wall 47, and the other engagement is connected to the left shaft end portion of the developing roller shaft 71 protruding from the left wall 46. Even when the stopper 92 is locked and the developing roller cover 89 is attached to the developing cartridge 26, one abutting portion 95 contacts the rear edge 82 of the rear lower wall portion 51 of the housing 36. Since the other abutment portion 95 abuts against the two gripping portions 79 of the blade unit 40, it is possible to prevent each abutment portion 95 from abutting against the rubber roller 72 of the developing roller 39. Therefore, the developing roller 39 is surely protected by the developing roller cover 89 by causing each contacting portion 95 to contact the rear end edge portion 82 and the two gripping portions 79 of the rear lower wall portion 51 of the housing 36. However, it is possible to prevent the surface of the rubber roller 72 from being damaged by the contact of each contact portion 95 when the developing roller cover 89 is mounted.

In addition, since the locking portions 91 and 92 are locked to the shaft end portions of the developing roller shaft 71, it is possible to prevent the locking portions 91 and 92 from coming into contact with the rubber roller 72 of the developing roller 39. it can. Therefore, when the developing roller cover 89 is attached, it is possible to prevent the surface of the rubber roller 72 from being damaged by the contact of the locking portions 91 and 92.
Further, in each contact portion 95, a plurality of contact ribs 98 are provided between the outer rib 96 and the inner rib 97, so that the rear end edge portion 82 of the rear lower wall portion 51 of the housing 36 is formed. Intrusion between the outer rib 96 and the inner rib 97 can be prevented. Therefore, each contact portion 95 can be reliably brought into contact with the rear end edge portion 82 and the two gripping portions 79 of the rear lower wall portion 51 of the housing 36.

  Further, both end portions of the developing roller shaft 71 protrude from the left side wall 46 and the right side wall 47 of the housing 36, and the shaft end portions of the developing roller shaft 71 are inserted into the locking portions 91 and 92, respectively. Possible locking holes 102 and 107 are respectively formed. When the shaft end portions of the developing roller shaft 71 are inserted into the locking holes 102 and 107, the locking portions 91 and 92 are connected to the developing roller shaft 71. It can be made to latch with respect to each axial end part. Therefore, the developing roller cover 89 can be reliably locked to the housing 36 with a simple configuration.

In addition, since both shaft end portions of the developing roller shaft 71 also serve as locking projections for locking the locking portions 91 and 92, the number of parts can be reduced compared to the configuration in which the locking projections are provided separately. It can reduce and can simplify a structure.
Further, since the operation portion 106 is provided in the other locking portion 92, if the operation portion 106 is operated, each elastic deformation portion 104 of the other locking portion 92 is opened to the outside in the longitudinal direction, that is, The locking hole 107 can be elastically deformed in a direction to be detached from the shaft end portion of the developing roller shaft 71. Therefore, the other locking portion 92 can be easily locked / detached with respect to the shaft end portion of the developing roller shaft 71. As a result, it is possible to reduce time and labor when the developing roller cover 89 is attached / detached to / from the developing cartridge 26.

Furthermore, when the developing cartridge 26 is attached to the developing cartridge 26,
Since the developing roller cover 89 that can prevent the contact portions 95 and the locking portions 91 and 92 from contacting the surface of the rubber roller 72 of the developing roller 39 is provided, the developing roller cover 89 is attached. Sometimes, the developing roller cover 89 can prevent the surface of the rubber roller 72 of the developing roller 39 from being damaged.

FIG. 11 is a perspective view showing another embodiment of the developing roller cover 89. In addition, about the part corresponding to each above-mentioned part, the same referential mark is attached | subjected in FIG. 11, and the description is abbreviate | omitted below.
In the developing roller cover 89 shown in FIG. 11, the operating portions 106 are provided in both the locking portions 91 and 92. That is, in this developing roller cover 89, like the other locking portion 92, one locking portion 91 includes an operation portion 106 that extends obliquely outward from the locking connection portion 101.

  Therefore, the developing roller cover 89 operates the operating portions 106 of the locking portions 91 and 92 at the same time so that the locking hole 102 of the locking portion 91 and the locking hole 107 of the locking portion 92 are respectively developed on the developing roller shaft. By attaching / detaching to the end portions of the shafts 71, it is possible to achieve attachment / detachment of the developing roller cover 89 with respect to the developing cartridge 26. Further, after the shaft end portion of the developing roller shaft 71 is inserted into the locking hole 102 of one locking portion 91 and the locking hole 102 is locked to the shaft end portion of the developing roller shaft 71, By operating the operating portion 106 of the locking portion 92 and locking the locking hole 107 of the locking portion 92 with the shaft end portion of the developing roller shaft 71, the developing roller cover 89 with respect to the developing cartridge 26 is locked. After the mounting is achieved or only the operating portion 106 of one locking portion 91 is operated to release the locking hole 102 of the locking portion 91 from the shaft end portion of the developing roller shaft 71, the developing roller cover It is also possible to achieve detachment of the developing roller cover 89 from the developing cartridge 26 by sliding 89 to disengage the engaging hole 107 of the other engaging portion 92 from the shaft end portion of the developing roller shaft 71.

In addition, since the developing roller cover 89 has a symmetrical shape also in the longitudinal direction of the cover 90, the developing roller cover 89 remains in the state shown in FIG. 6 regardless of which operation unit 106 is operated. If it can be mounted, it can also be mounted in the state shown in FIG. 6 upside down.
As a result, the workability when the developing roller cover 89 is attached to and detached from the developing cartridge 26 can be further improved.

  The developing roller cover 89 has a display 109 for recognizing one operation unit 106 as shown in FIG. If this display 109 is attached, even if the engaging portions 91 and 92 are provided with the operation portion 106, which operation portion is used when the developing roller cover 89 is attached to or detached from the developing cartridge 26. It is possible to easily recognize whether or not 106 should be operated.

FIG. 3 is a side cross-sectional view showing a main part of an embodiment of a laser printer provided with the developing cartridge of the present invention, showing a state in which a front cover is closed. It is principal part sectional drawing of the laser printer shown in FIG. 1, and shows the state which opened the front cover. FIG. 2 is a side sectional view of the developing cartridge shown in FIG. 1. FIG. 2 is a plan view of the developing cartridge shown in FIG. FIG. 2 is a perspective view showing a state when the developing cartridge shown in FIG. 1 is detached. FIG. 6 is a perspective view showing a state where a developing roller cover is attached to the developing cartridge shown in FIG. 5. FIG. 7 is a perspective view of the developing roller cover shown in FIG. 6. FIG. 7 is a plan view of the developing roller cover shown in FIG. 6. FIG. 7 is a bottom view of the developing cartridge to which the developing roller cover shown in FIG. 6 is attached. FIG. 7 is a side sectional view of a developing cartridge to which the developing roller cover shown in FIG. 6 is attached. It is a perspective view which shows other embodiment of a developing roller cover.

Explanation of symbols

26 Developing Cartridge 36 Housing 39 Developing Roller 43 Opening 46 Left Side Wall 47 Right Side Wall 71 Developing Roller Shaft 79 Holding Portion 82 Rear Edge Edge 89 Developing Roller Cover 90 Cover Portion 91 Locking Portion 92 Locking Portion 93 Restriction Portion 94 Main Body Portion 95 Contact part 96 Outer rib 97 Inner rib 98 Contact rib 102 Locking hole 106 Operation part 107 Locking hole 108 Bearing recess 109 Display

Claims (17)

A developing cartridge that includes a casing having a longitudinal opening and a developing roller that is provided in the casing and is disposed so that a part of the developing cartridge is exposed to the opening. In the developing roller cover for covering the opening in a state and protecting the surface of the developing roller,
In the mounted state, a cover portion facing the surface of the developing roller, extending in the axial direction of the developing roller, and having a symmetrical shape in a direction perpendicular to the axial direction of the developing roller;
A pair of locking portions that are provided at positions that are symmetrical with each other in the longitudinal direction with respect to the longitudinal center of the cover portion and that are locked to the housing in the mounted state. Characteristic developing roller cover.   The cover part is formed along a rectangular plate-like main body part and each edge in a direction orthogonal to the longitudinal direction of the main body part, protrudes from the main body part, and comes into contact with the housing in the mounted state 1 The developing roller cover according to claim 1, further comprising a pair of contact portions.   Each of the contact portions extends between the outer rib and the inner rib, and the outer rib and the inner rib that extend in the longitudinal direction of the main body portion and face each other with a gap in the direction orthogonal to the longitudinal direction. The developing roller cover according to claim 2, further comprising a plurality of contact ribs arranged at intervals in the longitudinal direction of the main body. The casing is provided with a first abutted portion and a second abutted portion on both sides of the opening in a direction perpendicular to the longitudinal direction of the opening,
4. The developing roller according to claim 2, wherein one of the pair of contact portions is in contact with the first contacted portion and the other is in contact with the second contacted portion. 5. cover. The developing cartridge is provided with a locking protrusion that protrudes outward from the housing in the axial direction of the developing roller,
The locking portion has a locking hole through which the locking protrusion can be inserted, and in the mounted state, the locking protrusion is inserted into the locking hole and locked to the locking protrusion. The developing roller cover according to claim 1, wherein the developing roller cover is provided.   The developing roller cover according to claim 5, wherein the locking protrusion is an end portion of the shaft of the developing roller protruding from the housing.   At least one of the pair of locking portions includes an operation portion that is formed so as to be elastically deformable in a direction in which the locking hole is detached from the locking protrusion in the mounted state, and is operated during the elastic deformation. The developing roller cover according to claim 5, wherein the developing roller cover is provided.   Both of the pair of locking portions are each provided with an operation portion that is formed so as to be elastically deformable in a direction in which the locking hole is detached from the locking protrusion in the mounted state, and is operated during the elastic deformation. The developing roller cover according to claim 7, wherein the developing roller cover is provided.   The developing roller cover according to claim 8, further comprising a display for recognizing the operation unit. The casing is provided with side walls on both sides in the longitudinal direction of the opening,
In the mounted state, the cover portion includes a pair of restricting portions that extend from both sides in the longitudinal direction of the cover portion in a direction opposite to the housing and abut against the side walls from the outside in the longitudinal direction of the cover portion. The developing roller cover according to claim 1, wherein:   The developing roller cover according to claim 10, wherein each of the restricting portions covers an exposed portion of the developing roller from an axially outer side in the mounted state.   12. The developing roller cover according to claim 10, wherein each of the restricting portions is disposed on an inner side in a longitudinal direction of the cover portion with respect to each of the locking portions.   The developing roller cover according to claim 12, wherein each of the restricting portions is formed with a receiving portion that receives the locking protrusion in the mounted state. A housing having a longitudinal opening;
A developing roller provided in the housing and disposed so as to be partially exposed in the opening;
A developing cartridge comprising the developing roller cover according to claim 1.   The housing includes a first contact portion and a second contact portion that are in contact with the developing roller cover on both sides of the opening in a direction perpendicular to the longitudinal direction of the opening when the developing roller cover is attached. The developing cartridge according to claim 14, further comprising a contact portion.   The housing includes an engaging projection that protrudes from the housing to the outside in the axial direction of the developing roller, and that engages the engaging portions of the developing roller cover in the mounted state. The developing cartridge according to claim 14 or 15.   The developing cartridge according to claim 16, wherein the locking protrusion is an end of a shaft of the developing roller protruding from the housing.

Images