JP4462114B2 - Developer cartridge - Google Patents

Description

  The present invention relates to a developing cartridge provided in an image forming apparatus such as a laser printer.

An electrophotographic image forming apparatus such as a laser printer has a photosensitive drum on which an electrostatic latent image is formed, and a developing cartridge for supplying toner is detachably mounted on the surface of the photosensitive drum. ing.
The developing cartridge includes a housing that stores the developer, and a developing roller that is rotatably supported by the housing and carries the developer. A longitudinal opening is formed in the housing, and the developing roller is disposed so that a part of the surface is exposed at the opening and faces the surface of the photosensitive drum. The developer in the housing is carried on the surface of the developing roller, and when it contacts the surface of the photosensitive drum as the developing roller rotates, an electrostatic latent image formed on the surface of the photosensitive drum is formed. Supplied.

Since a part of the surface of the developing roller is exposed from the housing, the exposed part of the surface of the developing roller may be damaged when the developing cartridge is detached from the image forming apparatus. Therefore, a cover member for protecting the developing roller is usually attached to the developing cartridge in a state where it is removed from the image forming apparatus.
As such a cover member, for example, a developing roller protective cover disposed opposite to the developing roller, a cover handle and a claw portion formed at the center of the upper end portion of the developing roller protective cover, and ribs formed at both ends of the lower end portion (For example, refer to Patent Document 1). In this cover member, the cover handle is gripped, each rib is hooked to the lower end portion of the developing cartridge, and the cover member is rotated with the hooked portion between each rib and the developing cartridge as a fulcrum, so that the claw portion is By engaging the developing cartridge, the cover member can be attached to the developing cartridge.
JP 2003-195730 A

  However, in addition to the above-described configuration, for example, a configuration in which the cover member is locked on both sides in the longitudinal direction of the opening of the housing of the developing cartridge is conceivable. For example, when the shaft end portion of the developing roller protrudes from both side walls of the housing, the longitudinal end of the cover member is locked to one shaft end portion of the developing roller, and then the other end of the developing roller. By locking the other end portion of the cover member in the longitudinal direction with the shaft end portion, the cover member can be mounted so as to close the opening of the housing.

  However, when one end of the cover member in the longitudinal direction is locked to the shaft end of the developing roller, the cover member swings in the direction intersecting the longitudinal direction with the shaft end as the center. Sometimes, if the edge extending in the longitudinal direction of the cover member is not arranged along the edge of the opening of the housing, the edge extending in the longitudinal direction of the cover member enters the opening, and the surface of the developing roller The surface of the developing roller may be damaged.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a developing cartridge provided with a developing roller cover that can prevent contact with the surface of the developing roller when mounted on the developing cartridge.

In order to achieve the above object, the invention according to claim 1 is arranged in the opening so that a casing having a longitudinal opening is formed and a part of the casing is exposed to the outside of the casing. And a layer thickness regulation for regulating the layer thickness of the developing roller supported by the casing with both end portions of the shaft projecting outside the casing, and the developer carried on the surface of the developing roller. A reinforcing cartridge extending along the longitudinal direction of the opening on one side of the housing in a direction orthogonal to the longitudinal direction of the opening; and the housing And a developing roller cover that protects the surface of the developing roller in a mounted state with respect to the housing, and the layer thickness regulating member faces the developing roller. The blade body and the cross-section are approximately L-shaped A support member that is bent and extends in the axial direction of the developing roller and supports the blade body on the housing, the support member including an extending portion that extends toward the outside of the housing, In the mounted state, the developing roller cover is disposed opposite to the surface of the developing roller and extends in the longitudinal direction of the opening. The developing roller cover is orthogonal to the longitudinal direction from both longitudinal ends of the cover body. In the longitudinal direction, opposed to each other with a gap larger than the gap between the outer side surfaces of the casing in the longitudinal direction, and locked to the end of the shaft protruding from the casing in the mounted state. A locking portion extending in the longitudinal direction of the cover body portion, and in the mounted state, extending in the longitudinal direction of the cover body portion, a first cover edge portion disposed along the extending portion, and in front In the mounted state, the second cover edge is disposed along the reinforcing portion and is opposed to the first cover edge in a direction orthogonal to the longitudinal direction of the cover main body, and provided on the first cover edge. When mounting on the housing, the first cover edge is guided so that the first cover edge is disposed along the extended portion of the support member extending in the longitudinal direction at the periphery of the opening. The reinforcing member is provided at both ends in the longitudinal direction of the first guide portion and the second cover edge portion, and the second cover edge portion extends in the longitudinal direction at the peripheral edge of the opening portion when mounted on the housing. And a second guide portion for guiding the second cover edge portion so that one of the locking portions is mounted on the casing with the developing roller cover. Check the operating part It is physically provided and has the flexibility to be elastically deformable so as to open outward in the longitudinal direction .

According to such a configuration, when the developing roller cover is attached to the developing cartridge, the cover edge portion extending in the longitudinal direction of the cover main body portion by the guide portion becomes the opening edge portion extending in the longitudinal direction at the peripheral edge of the opening portion of the housing. It is guided so that it may be arranged along. Thereby, it can prevent that a cover edge part enters into the opening part of a housing | casing. Therefore, when the developing roller cover is attached to the developing cartridge, it is possible to prevent the cover edge from contacting the surface of the developing roller, and it is possible to prevent damage to the surface of the developing roller due to such contact.
Further, the engaging portion on the opposite side to the engaging portion having flexibility is engaged with the developing cartridge, and with this as a fulcrum, the developing roller cover is brought close to the developing cartridge, and the engaging portion having flexibility is developed. When the cartridge is locked, the flexible locking portion can be easily deformed. Therefore, the locking portion having flexibility can be easily locked to the developing cartridge, and the time and labor when the developing roller cover is attached to the developing cartridge can be reduced.
Further, since the locking portion is locked to the end portion of the shaft of the developing roller, it is not necessary to separately provide a member for locking the locking portion to the developing cartridge. Therefore, the number of parts of the developing cartridge can be reduced, and the configuration of the developing cartridge can be simplified. Further, by engaging the engaging portion with the shaft of the developing roller, the developing roller cover easily swings with the shaft as a fulcrum when the developing roller cover is mounted. The portion can be prevented from entering the opening of the housing.
Further, when the developing roller cover is attached to the developing cartridge, the first cover edge is guided along the opening edge by the guide provided in the first cover edge, while the second cover The guide portion provided at the cover edge portion guides the second cover edge portion so as to be disposed along the opening edge portion. In other words, each of the cover edge portions (the first cover edge portion and the second cover edge portion) is guided so as to be arranged along the opening edge portion on both sides in the direction orthogonal to the longitudinal direction of the cover main body portion. Thereby, it can prevent reliably that both cover edge parts enter into the opening part of a housing | casing. Therefore, when the developing roller cover is attached to the developing cartridge, the edges of both covers can be prevented from coming into contact with the surface of the developing roller, and damage to the surface of the developing roller due to such contact can be prevented.
Further, when the developing roller cover is attached to the developing cartridge, the guide cover provided at the first cover edge guides the first cover edge to be disposed along the layer thickness regulating member. Thereby, it can prevent that a 1st cover edge part enters into the opening part of a housing | casing.
Further, when the developing roller cover is attached to the developing cartridge, the guide portion provided at the second cover edge portion guides the second cover edge portion to be disposed along the reinforcing portion. Thereby, it is possible to prevent the second cover edge from entering the opening of the housing.
Further, since the developing roller cover is provided to prevent the cover edge from coming into contact with the surface of the developing roller when mounted on the developing cartridge, the cover edge of the developing roller cover is mounted when the developing roller cover is mounted. It is possible to prevent the surface of the developing roller from being damaged by the contact.

According to a second aspect of the present invention, in the first aspect of the present invention, the guide portion provided at the first cover edge portion is connected to the developing roller across the opening edge portion in the mounted state. It is characterized by being arranged on the opposite side.
According to such a configuration, in a state where the developing roller cover is mounted on the developing cartridge, the guide portion provided on the first cover edge is disposed on the opposite side of the developing roller across the opening edge. Therefore, when the developing roller cover is attached to the developing cartridge, the guide portion can be prevented from entering the opening of the housing. As a result, the guide portion can be prevented from coming into contact with the surface of the developing roller when the developing roller cover is attached to the developing cartridge, and damage to the surface of the developing roller due to such contact can be prevented.

The invention according to claim 3 is the invention according to claim 1 or 2 , wherein the housing includes two side walls facing each other across the opening in the longitudinal direction of the opening. The guide portion provided at the edge of the first cover enters between the two side walls in the mounted state.
According to such a configuration, since the guide portion provided at the edge of the first cover enters between the both side walls of the housing, it is possible to prevent the developing roller cover from rattling in the longitudinal direction of the opening.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the guide portion provided on the first cover edge extends along the first cover edge, and has both longitudinal ends thereof. A notch for avoiding interference with the side wall is formed in the part.
According to such a configuration, when the developing roller cover is attached to the developing cartridge, it is possible to avoid that both ends in the longitudinal direction of the guide portion provided on the edge portion of the first cover contact (interference) with the side wall of the housing. . Therefore, the guide part provided in a 1st cover edge part can be smoothly entrapped between the both side walls of a housing | casing.

The invention according to claim 5 is the invention according to any one of claims 1 to 4 , further comprising a positioning portion for positioning the developing roller cover in the longitudinal direction of the opening in the mounted state. It is characterized by having.
According to such a configuration, since the developing roller cover is positioned in the longitudinal direction of the opening, it is possible to prevent the developing roller cover from being displaced in the longitudinal direction of the opening. Therefore, when the developing roller cover is attached to the developing cartridge, the longitudinal end portion of the developing roller cover can be prevented from entering the opening of the housing, and the surface of the developing roller is damaged by the contact of the longitudinal end portion. Can be prevented. In addition, after the development roller cover is attached to the development cartridge, the development roller cover can be prevented from rattling in the longitudinal direction of the opening.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, one of the locking portions has flexibility, and the positioning portion has the flexibility. It is characterized by being provided at a position offset to the opposite side to the part.
According to such a configuration, when one of the locking portions is flexible, the locking portion on the opposite side of the locking portion is locked to the developing cartridge, and this is used as a fulcrum, and the developing roller cover Is attached to the developer cartridge, and the developing roller cover is opened during the process of attaching the developing roller cover by providing a positioning part that is offset to the opposite side of the flexible locking part. It can be positioned in the longitudinal direction of the part. Therefore, when the developing roller cover is attached to the developing cartridge, it is possible to more reliably prevent the end portion in the longitudinal direction of the developing roller cover from contacting the developing roller. As a result, damage to the surface of the developing roller due to contact with the developing roller cover can be further prevented. Further, the positioning tolerance in the process of mounting the developing roller cover can be reduced by shifting the positioning portion toward the locking portion serving as a fulcrum.

The invention according to claim 7 is the invention according to claim 5 or 6 , wherein the opening edge portion includes a fitting portion extending in a direction orthogonal to a longitudinal direction of the opening, and the positioning is performed. The portion is formed by cutting the cover edge portion, and is characterized by fitting the fitting portion in the mounted state.
According to such a configuration, the positioning of the developing roller cover in the longitudinal direction is achieved by fitting the fitting portion provided at the opening edge portion into the positioning portion formed by cutting the cover edge portion. The Therefore, reliable positioning in the longitudinal direction of the developing roller cover can be achieved with a simple configuration.

The invention according to claim 8 is the invention according to any one of claims 1 to 7 , wherein the cover main body is opposed to the roller having an arcuate cross section when cut by a plane perpendicular to the longitudinal direction. It is characterized by having a part.
According to such a configuration, since the cover body portion is provided with the roller facing portion having an arcuate cross section, the strength of the cover body portion can be increased.

The invention according to claim 9 is the packaging according to the invention according to claim 8, wherein the developing cartridge is swelled when the developing cartridge is packed in the mounted state. It is characterized by having a receiving part that can be received by the material.
According to such a configuration, since the receiving part is provided in the cover main body part, when the developing cartridge is packed, the receiving part is received by the packing material so that the developing cartridge can be packed in a stable state. Can do. Further, since the receiving portion bulges from the cover main body portion, a step is formed between the receiving portion and the cover main body portion, so that the strength of the cover main body portion can be further increased.

The invention according to claim 10 is characterized in that, in the invention according to claim 9, the receiving portions are formed at both ends in the longitudinal direction of the cover main body.
According to such a configuration, since the receiving portions are formed at both end portions in the longitudinal direction of the cover main body portion, the strength of the cover main body portion can be further increased while the developing cartridge can be packed in a more stable state. Can be achieved.

According to the first aspect of the present invention, it is possible to prevent the cover edge from coming into contact with the surface of the developing roller when the developing roller cover is attached to the developing cartridge, and the surface of the developing roller due to such contact can be prevented. Damage can be prevented.
Further, the locking portion having flexibility can be easily locked to the developing cartridge, and the labor for mounting the developing roller cover to the developing cartridge can be reduced.
Further, the number of parts of the developing cartridge can be reduced, and the configuration of the developing cartridge can be simplified. Further, by engaging the engaging portion with the shaft of the developing roller, the developing roller cover easily swings with the shaft as a fulcrum when the developing roller cover is mounted. The portion can be prevented from entering the opening of the housing.
Further, when the developing roller cover is attached to the developing cartridge, it is possible to prevent both cover edges from coming into contact with the surface of the developing roller, and it is possible to prevent damage to the surface of the developing roller due to such contact.
Further, it is possible to prevent the first cover edge from entering the opening of the housing.
Further, it is possible to prevent the second cover edge from entering the opening of the housing.

According to the second aspect of the present invention, when the developing roller cover is attached to the developing cartridge, the guide portion provided at the edge of the first cover can be prevented from coming into contact with the surface of the developing roller. Damage to the surface of the developing roller due to contact can be prevented.
According to the third aspect of the present invention, it is possible to prevent the developing roller cover from rattling in the longitudinal direction of the opening.

  According to the fourth aspect of the present invention, the guide portion provided at the edge of the first cover can smoothly enter between both side walls of the housing.

According to the fifth aspect of the present invention, when the developing roller cover is attached to the developing cartridge, damage to the surface of the developing roller due to contact with the developing roller cover can be further prevented, but after the mounting, the developing roller cover Can be prevented from rattling in the longitudinal direction of the opening.
According to the sixth aspect of the present invention, damage to the surface of the developing roller due to contact with the developing roller cover can be further prevented.

According to the seventh aspect of the present invention, reliable positioning in the longitudinal direction of the developing roller cover can be achieved with a simple configuration .

According to the invention described in 請 Motomeko 8, it is possible to increase the strength of the cover body portion.
According to the ninth aspect of the present invention, the strength of the cover main body can be further increased while the developing cartridge can be packed in a stable state.
According to the tenth aspect of the present invention, the strength of the cover main body can be further increased while the developing cartridge can be packed in a more stable state .

1. 1 is a side sectional view showing an embodiment of a laser printer provided with a developing cartridge of the present invention.
The laser printer 1 includes a main body casing 2, a feeder unit 4 for feeding paper 3 in the main body casing 2, and image formation for forming an image on the paper 3 fed by the feeder unit 4. Part 5.
(1) Main Body Casing An attachment / detachment opening 6 for attaching / detaching a process cartridge 20 described later is formed on one side wall of the main body casing 2, and a front cover 7 for opening / closing the attachment / detachment opening 6 is provided. ing. The front cover 7 is rotatably supported by a cover shaft 8 inserted through a lower end portion thereof. Thus, when the front cover 7 is closed with the cover shaft 8 as a fulcrum, the attachment / detachment opening 6 is closed by the front cover 7, and when the front cover 7 is opened with the cover shaft 8 as a fulcrum, the attachment / detachment opening 6 is opened. The process cartridge 20 can be attached to and detached from the main casing 2 through the attachment / detachment port 6.

In the following description, 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”. Further, in the process cartridge 20 (developing cartridge 30), the front cover 7 side is referred to as “front side” and the opposite side is referred to as “rear side” in the state where it is mounted on the main body casing 2.
(2) Feeder unit The feeder unit 4 includes a paper feed tray 9 that is detachably attached to the bottom of the main body casing 2 along the front-rear direction, and a separation roller 10 that is provided above the front end of the paper feed tray 9. And a separation pad 11 and a paper feed roller 12 provided on the rear side of the separation roller 10 (upstream side of the separation pad 11 in the conveyance direction of the paper 3). In addition, the feeder unit 4 includes a paper dust removing roller 13 provided on the upper front side of the separation roller 10 (downstream in the conveyance direction of the paper 3 with respect to the separation roller 10), and a pinch disposed to face the paper dust removing roller 13. And a roller 14.

The conveyance path of the paper 3 in the feeder unit 4 is folded back in a substantially U shape from the vicinity of the paper dust removing roller 13 and extends substantially horizontally toward the process cartridge 20. And the feeder part 4 is provided with the registration roller 15 which consists of a pair of roller on the part extended in the substantially horizontal of the conveyance path | route.
Inside the paper feed tray 9, there is provided a paper pressing plate 16 on which the paper 3 can be stacked. The paper pressing plate 16 is supported at the rear end so as to be swingable, so that the front end is disposed below, the placement position along the bottom plate of the paper feed tray 9 and the front end are disposed above, It can be swung between an inclined supply position.

  A lever 17 for lifting the front end of the paper pressing plate 16 upward is provided at the front end of the paper feed tray 9. The lever 17 is supported at a position below the front end of the paper pressing plate 16 so that the rear end is swingably supported by the lever shaft 18, and the front end is inclined to the bottom plate of the paper feed tray 9. The sheet pressing plate 16 can be swung between an inclined posture to lift the paper pressing plate 16. When a driving force is input to the lever shaft 18, the lever 17 rotates with the lever shaft 18 as a fulcrum, the front end portion of the lever 17 lifts the front end portion of the paper pressing plate 16, and the paper pressing plate 16 is brought to the supply position. Move.

When the sheet pressing plate 16 is positioned at the supply position, the uppermost sheet 3 on the sheet pressing plate 16 is pressed by the sheet feeding roller 12, and the separation roller 10 and the separation pad 11 are rotated by the rotation of the sheet feeding roller 12. Feeding is started toward the separation position between the two.
When the paper feed tray 9 is detached from the main casing 2, the paper pressing plate 16 is positioned at the placement position. When the paper pressing plate 16 is positioned at the mounting position, the paper 3 can be stacked on the paper pressing plate 16.

  The sheet 3 fed toward the separation position by the sheet feeding roller 12 is rolled and fed one by one when it is sandwiched between the separation roller 10 and the separation pad 11 by the rotation of the separation roller 10. Is done. The fed paper 3 passes between the paper dust removing roller 13 and the pinch roller 14, and after the paper dust is removed there, the paper 3 is folded back along the U-shaped paper feeding side conveyance path, and the registration roller It is conveyed toward 15.

The registration roller 15 conveys the sheet 3 to the transfer position between the photosensitive drum 28 and the transfer roller 31 after the registration, and to transfer the toner image on the photosensitive drum 28 to the sheet.
(3) Image Forming Unit The image forming unit 5 includes a scanner unit 19, a process cartridge 20, and a fixing unit 21.
<Scanner part>
The scanner unit 19 is provided in the upper part of the main casing 2 and includes a laser light source (not shown), a polygon mirror 22 that is driven to rotate, an fθ lens 23, a reflecting mirror 24, a lens 25, and a reflecting mirror 26. The laser beam based on the image data emitted from the laser light source is deflected by the polygon mirror 22 and passes through the fθ lens 23 as shown by a chain line, and then the optical path is turned back by the reflecting mirror 24 and further passes through the lens 25. Thereafter, the optical path is further bent downward by the reflecting mirror 26, so that the surface of the photosensitive drum 28 of the process cartridge 20 is irradiated.
<Process cartridge>
FIG. 2 is a sectional side view of the process cartridge.

The process cartridge 20 is provided below the scanner unit 19 in the main body casing 2 and is detachably attached to the main body casing 2 via the attachment / detachment port 6.
As shown in FIG. 2, the process cartridge 20 includes a drum frame 27 and a photosensitive drum 28, a scorotron charger 29, a developing cartridge 30, a transfer roller 31, and a cleaning unit 32 provided in the drum frame 27. I have.

  The drum frame 27 includes a drum front opening 113 for transporting the paper 3 from outside the drum frame 27 to the transfer position, and a drum rear opening 114 for transporting the paper 3 from the transfer position to the outside of the drum frame 27. Is formed. The drum front opening 113 is disposed below the developing cartridge 30 and in front of the transfer position, and is arranged along the axial direction of the transfer roller 31 (hereinafter sometimes simply referred to as “axial direction”). It is opened so as to communicate between the inside and the outside. The drum rear opening 114 is disposed on the rear side of the transfer position so as to face the drum front opening 113 with the transfer position interposed therebetween, and communicates the inside and outside of the drum frame 27 along the axial direction. It is open.

  The photosensitive drum 28 has a cylindrical shape, and the outermost layer is formed of a positively chargeable photosensitive layer made of polycarbonate or the like. And a metal drum shaft 34 that extends. The drum shaft 34 is supported by the drum frame 27, and the drum main body 33 is rotatably supported by the drum shaft 34, so that the photosensitive drum 28 can be rotated about the drum shaft 34 in the drum frame 27. Is provided. Further, the photosensitive drum 28 is rotationally driven by receiving a driving force from a motor (not shown).

  The scorotron charger 29 is supported by the drum frame 27 obliquely above the rear side of the photosensitive drum 28, and is opposed to the photosensitive drum 28 with a gap so as not to contact the photosensitive drum 28. The scorotron charger 29 is provided between the discharge wire 35 and the photosensitive drum 28, which is disposed to face the photosensitive drum 28 with a space therebetween, and controls the amount of discharge to the photosensitive drum 28. Grid 49. In the scorotron charger 29, a bias voltage is applied to the grid 49, and at the same time, a high voltage is applied to the discharge wire 35 to cause corona discharge of the discharge wire 35, so that the surface of the photosensitive drum 28 is uniformly positive. To charge.

The developing cartridge 30 is detachably attached to the drum frame 27. Therefore, the developing cartridge 30 can be attached to and detached from the main body casing 2 while being attached to the drum frame 27, or can be attached and detached alone while the drum frame 27 remains in the main body casing 2. .
The developing cartridge 30 includes a housing 36, a supply roller 37 provided in the housing 36, a developing roller 38, and a layer thickness regulating member 39 as an opening edge.

As will be described in detail later, the housing 36 is formed in a box shape whose rear side is opened. Inside the housing 36, a partition wall 40, a toner storage chamber 41 and a developing chamber 42 that are partitioned by the partition wall 40 are provided.
The toner storage chamber 41 is partitioned as an internal space on the front side of the housing 36 partitioned by the partition wall 40. In the toner storage chamber 41, positively charged nonmagnetic one-component toner is stored as a developer. In the toner, a polymerizable monomer, for example, a styrene monomer such as styrene, an acrylic monomer such as acrylic acid, alkyl (C1 to C4) acrylate, alkyl (C1 to C4) methacrylate, A polymerized toner obtained by copolymerization by suspension polymerization or the like is used. This polymerized toner has a substantially 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 average particle size of the toner is about 6 to 10 μm.
Further, an agitator 45 for agitating the toner is provided in the toner storage chamber 41. The agitator 45 includes an agitator rotating shaft 46 extending in the width direction (a direction orthogonal to the front-rear direction and the up-and-down direction, the same shall apply hereinafter) in the approximate center of the toner storage chamber 41, and a stirring member 47 provided on the agitator rotating shaft 46. It has. When a driving force from a motor (not shown) is input to the agitator rotating shaft 46, the agitator rotating shaft 46 is rotated, and the stirring member 47 moves in the toner containing chamber 41 in the circumferential direction around the agitator rotating shaft 46. Then, the toner in the toner storage chamber 41 is stirred by the stirring member 47 and discharged from the communication port 43 below the partition wall 40 to the developing chamber 42.

The developing chamber 42 is partitioned as an internal space on the rear side of the housing 36 partitioned by the partition wall 40.
The supply roller 37 is disposed behind the communication port 43 in the developing chamber 42. The supply roller 37 includes a metal supply roller shaft 50 and a sponge roller 51 made of a conductive foam material that covers the supply roller shaft 50. The supply roller shaft 50 extends in the width direction, and both ends thereof are rotatably supported by the housing 36. The supply roller 37 is rotationally driven when a driving force from a motor (not shown) is input to the supply roller shaft 50.

  The developing roller 38 is disposed behind the supply roller 37 in the developing chamber 42 and is in contact with the supply roller 37 so as to be compressed. Further, the developing roller 38 is disposed opposite to the photosensitive drum 28 from the upper front side obliquely with the developing cartridge 30 mounted on the drum frame 27, and is located below the central portion in the vertical direction that protrudes most rearward. Is in contact with the photosensitive drum 28. The developing roller 38 includes a metallic developing roller shaft 52 and a rubber roller 53 made of a conductive rubber material that covers the developing roller shaft 52. The developing roller shaft 52 extends in the width direction, and both ends thereof are rotatably supported by the housing 36. The rubber roller 53 is made of conductive urethane rubber or silicone rubber containing carbon fine particles, and the surface thereof is coated with a urethane rubber or silicone rubber coating layer containing fluorine. The developing roller 38 is rotationally driven when a driving force from a motor (not shown) is input to the developing roller shaft 52. A developing bias is applied to the developing roller 38 during development.

  The layer thickness regulating member 39 includes a blade body 54 made of a metal leaf spring material, a pressing portion 55 having a semicircular cross section made of insulating silicone rubber provided at a free end portion of the blade body 54, and a blade body. An attachment member 109 for attaching the base end portion of 54 to the rear end portion of the housing 36 is provided. A seal member 110 is interposed between the mounting member 109 and the rear end portion of the housing 36 to prevent toner leakage from the space.

The attachment member 109 includes a front support member 115 and a back support member 111 that sandwich the base end portion of the blade body 54, and a plurality of (four in this embodiment) assembled screws 112 for fixing them together. It has.
The front support member 115 is made of a rectangular metal plate extending in the width direction, and has a front surface in contact with the seal member 110 and a rear surface in contact with the proximal end portion of the blade body 54.

  The back support member 111 is formed by bending a metal plate into a substantially L-shaped cross section, and is disposed opposite to the rear end side of the base end portion of the blade body 54. More specifically, the back support member 111 includes a holding portion 131 that extends in the width direction and contacts the base end portion of the blade body 54, and an extending portion 132 that extends rearward from the lower end edge of the holding portion 131. Integrated.

The assembled screw 112 passes through the blade body 54 in the front-rear direction in a state where the proximal end portion of the blade body 54 is sandwiched between the back support member 111 and the sandwiching portion 131 of the front support member 115.
Then, the layer thickness regulating member 39 is formed by the fixing screw 130 that the front support member 115 of the mounting member 109 faces the rear end portion of the housing 36 with the seal member 110 interposed therebetween, and passes through both end portions in the width direction. 36 (see FIGS. 3 and 4). In a state where the layer thickness regulating member 39 is fixed to the housing 36, the blade body 54 extends from the upper side of the developing roller 38 obliquely downward to the front side, and the pressing portion 55 provided at the free end portion of the blade body 54 includes: The blade body 54 is pressed against the developing roller 38 by the elastic force.

  The toner discharged from the communication port 43 is supplied to the developing roller 38 by the rotation of the supply roller 37, and at this time, the toner is triboelectrically charged between the supply roller 37 and the developing roller 38. The toner supplied onto the developing roller 38 enters between the pressing portion 55 of the layer thickness regulating member 39 and the rubber roller 53 of the developing roller 38 as the developing roller 38 rotates, and forms a thin layer with a constant thickness. It is carried on the developing roller 38.

  The transfer roller 31 is provided below the photosensitive drum 28 in the drum frame 27, and is opposed to and contacts the photosensitive drum 28 in the vertical direction so as to form a nip with the photosensitive drum 28. The transfer roller 31 includes a metal transfer roller shaft 56 and a rubber roller 57 made of a conductive rubber material that covers the transfer roller shaft 56. The transfer roller shaft 56 extends in the width direction and is rotatably supported by the drum frame 27. The transfer roller 31 is rotationally driven by receiving a driving force from a motor (not shown). A transfer bias is applied to the transfer roller 31 at the time of transfer.

The cleaning unit 32 is attached to the drum frame 27, and is disposed opposite the photosensitive drum 28 on the rear side of the photosensitive drum 28. The cleaning unit 32 is disposed so as to face and contact the photosensitive drum 28, and includes a cleaning brush 58 for scraping off paper dust and the like attached to the photosensitive drum 28.
Referring to FIG. 1, the surface of the photosensitive drum 28 is first uniformly charged to a positive polarity by a scorotron charger 29 as the photosensitive drum 28 rotates, and then the laser beam from the scanner unit 19 is charged. And an electrostatic latent image corresponding to an image to be formed on the paper 3 is formed.

  Next, when the developing roller 38 rotates, the toner carried on the developing roller 38 and charged with positive polarity is formed on the surface of the photosensitive drum 28 when it comes into contact with the photosensitive drum 28. The electrostatic latent image, that is, the surface of the photosensitive drum 28 that is uniformly charged to the positive polarity, is supplied to the exposed portion exposed to a laser beam and having a lowered potential. As a result, the electrostatic latent image on the photosensitive drum 28 is visualized, and a toner image by reversal development is carried on the surface of the photosensitive drum 28.

  Thereafter, the toner image carried on the surface of the photosensitive drum 28 is transferred from the outside of the drum frame 27 to the drum frame 27 through the drum front opening 113 by the sheet 3 conveyed by the registration roller 15, and the photosensitive drum 28. While passing through the transfer position between the drum 28 and the transfer roller 31, the image is transferred to the paper 3 by the transfer bias applied to the transfer roller 31. The sheet 3 onto which the toner image has been transferred is conveyed from the drum frame 27 to the outside of the drum frame 27 via the drum rear side opening 114, and is conveyed to the fixing unit 21.

Note that the transfer residual toner remaining on the photosensitive drum 28 after the transfer is collected by the developing roller 38. Further, paper dust from the paper 3 adhering to the photosensitive drum 28 after the transfer is collected by the cleaning brush 58 of the cleaning unit 32.
<Fixing part>
The fixing unit 21 is provided on the rear side of the process cartridge 20. The fixing unit 21 includes a fixing frame 59 and a heating roller 60 and a pressure roller 61 in the fixing frame 59.

The heating roller 60 includes a metal tube whose surface is coated with a fluororesin and a halogen lamp for heating inserted in the metal tube. The heating roller 60 is rotationally driven by inputting a driving force from a motor (not shown).
The pressure roller 61 is disposed opposite the heating roller 60 so as to press the heating roller 60. The pressure roller 61 includes a metal roller shaft and a rubber roller made of a rubber material that covers the roller shaft. The pressure roller 61 is driven according to the rotational drive of the heating roller 60.

In the fixing unit 21, the toner image transferred onto the paper 3 at the transfer position is thermally fixed while the paper 3 passes between the heating roller 60 and the pressure roller 61. The sheet 3 on which the toner image is fixed is conveyed toward a paper discharge tray 62 formed on the upper surface of the main casing 2.
The paper discharge side transport path of the sheet 3 from the fixing unit 21 to the paper discharge tray 62 is folded back to the front side in a substantially U shape from the fixing unit 21. In the discharge side transfer path, a transfer roller 63 is provided in the middle, and a discharge roller 64 is provided at the downstream end.

The sheet 3 thermally fixed in the fixing unit 21 is transported along a transport path from the fixing unit 21 to the paper discharge tray 62 by the transport roller 63, and is discharged onto the paper discharge tray 62 by the paper discharge roller 64.
2. 3 is a perspective view of the developing cartridge as viewed obliquely from the rear, FIG. 4 is a rear view of the developing cartridge, and FIG. 5 is a side view of the developing cartridge. FIG. 6 is a bottom view of the developing cartridge.

As shown in FIGS. 2 and 3, the housing 36 of the developing cartridge 30 is formed in a box shape that integrally includes a top wall 70, a front wall 72, both side walls 69, and a bottom wall 71, with the rear side being opened. An open portion on the rear side is formed as an opening 94.
As shown in FIG. 3, the opening 94 includes a rear end edge of the back support member 111 of the layer thickness regulating member 39, a rear end edge of the side walls 69, and a rear end edge of the bottom wall 71 (a rear bottom wall 76 described later). The rear end 68) extends in the width direction and is opened in a substantially rectangular shape when viewed from the back. In the opening 94, both end portions of the developing roller shaft 52 of the developing roller 38 are rotatably supported in a state of protruding from both side walls 69 of the housing 36, and the rubber roller 53 of the developing roller 38 is supported from the opening 94 to the housing. It is arranged so as to be exposed to the outside of the body 36. More specifically, insertion holes 121 facing each other in the width direction are provided at the rear ends of the side walls 69 of the housing 36, and the developing roller shaft 52 is inserted into the insertion holes 121, so that the rubber rollers 53 are inserted. The developing roller 38 is rotatably supported by the housing 36 such that the center in the vertical direction protrudes most out of the housing 36 from the inside of the housing 36 through the opening 94.

As shown in FIG. 2, the upper wall 70 has a flat plate shape in plan view, and closes above the toner storage chamber 41 and the developing chamber 42.
The front wall 72 has a flat plate shape when viewed from the front, is formed to extend downward from the front end portion of the upper wall 70, and closes the front side of the toner storage chamber 41.
As shown in FIGS. 3 and 5, the side walls 69 are formed in a plate shape extending in the front-rear direction, and close the sides of the toner storage chamber 41 and the developing chamber 42. The agitator rotating shaft 46, the supply roller shaft 50, and the developing roller shaft 52 are rotatably supported by the side walls 69, and on one side wall 69, as shown in FIG. 3, the agitator rotating shaft 46, the supply roller shaft A gear mechanism (not shown) for rotationally driving 50 and the developing roller shaft 52 and a gear cover 79 covering the gear mechanism are provided.

As shown in FIG. 2, the bottom wall 71 closes the lower part of the toner storage chamber 41 and the developing chamber 42 and integrally includes a front bottom wall 74, a central bottom wall 75, and a rear bottom wall 76.
The front bottom wall 74 is formed in a substantially semicircular cross section along the rotation locus of the agitator 45 in the toner storage chamber 41.
The central bottom wall 75 is disposed on the rear side of the front bottom wall 74 and has a substantially semicircular cross section along the supply roller 37 in the developing chamber 42.

The rear bottom wall 76 is disposed on the rear side of the central bottom wall 75 and is formed in a tongue plate shape that is inclined downward from the front side toward the rear side.
On the upper surface of the rear bottom wall 76, a lower film 87 for preventing toner leakage from between the rear bottom wall 76 and the developing roller 38 is provided. The lower film 87 is made of PET (polyethylene terephthalate), extends obliquely upward from the upper surface of the rear bottom wall 76, and is disposed so as to contact the peripheral surface of the rubber roller 53 of the developing roller 38.

As shown in FIGS. 3 and 4, the rear end portion 68 of the rear bottom wall 76 extends along the width direction of the housing 36. A rear end portion 68 of the rear bottom wall 76 is provided with partial rear walls 73 at both ends in the width direction, and a reinforcing portion 80 as an opening edge portion is provided between them.
Both partial rear walls 73 are arranged to face each other with a space therebetween in the width direction, and are provided so as to extend upward from both end portions in the width direction of the rear end portion 68. The partial rear wall 73 is formed in a substantially L-shaped plate as viewed from the back, with a portion of the lower portion in the width direction cut out.

The reinforcing portion 80 extends between the rear wall portions 73 along the rear end portion 68, and is provided so as to fit into the notched portions of the rear wall portions 73. As shown in FIG. 3, the reinforcing portion 80 is integrally formed with a reinforcing upper wall 82, a reinforcing front wall 85, a reinforcing bottom wall 83, and both reinforcing side walls 84, and is formed in a box shape with the rear side opened. .
The reinforcing upper wall 82 is provided along the rear end portion 68 continuously to the rear end portion 68 and is formed so as to protrude rearward.

The reinforcing front wall 85 is provided along the rear end portion 68 and is formed in a substantially rectangular elongated flat plate shape extending downward from the front end portion of the reinforcing upper wall 82.
The reinforcing bottom wall 83 has a substantially rectangular elongated flat plate shape extending along the rear end portion 68 and is disposed so as to face the reinforcing upper wall 82 in the vertical direction, and obliquely rearward and downward from the lower end portion of the reinforcing front wall 85. It is formed to extend toward. On the upper surface of the reinforcing bottom wall 83, a flat plate-like fitting portion 133 extending in the vertical direction and the front-rear direction is formed at a position offset to one reinforcing side wall 84 side (right side in the rear view).

Both reinforcing side walls 84 have a substantially rectangular flat plate shape, and are arranged at both ends in the width direction of the reinforcing upper wall 82, the reinforcing front wall 85, and the reinforcing bottom wall 83 so as to face each other in the width direction.
Further, as shown in FIGS. 3 and 6, a guide portion 81 for guiding the paper 3 is provided on the lower surface of the bottom wall 71. The guide portion 81 has a flat plate shape extending in the front-rear direction, is formed so as to protrude downward from the bottom wall 71, and a plurality of guide portions 81 are provided so as to be parallel to each other in the width direction. As shown in FIG. 2, each guide portion 81 has a rear end portion 105 connected to the reinforcing front wall 85 and the reinforcing bottom wall 83, and a front end portion 104 connected to the front bottom wall 74.

The housing 36 is provided with a gripping portion 77 that is gripped when the developing cartridge 30 and the process cartridge 20 are attached and detached. The grip portion 77 is formed so as to protrude forward from the upper portion of the front wall 72 of the housing 36.
3. FIG. 7 is a perspective view of the developing cartridge to which the developing roller cover is attached as seen from one side obliquely rearward in the width direction, and FIG. 8 is seen from the other side obliquely rearward in the widthwise direction of the developing cartridge. It is a perspective view. 9 is a plan view of the developing cartridge to which the developing roller cover is attached, FIG. 10 is a rear view of the developing cartridge, FIG. 11 is a bottom view of the developing cartridge, and FIG. FIG. 13 is a side sectional view of the developing cartridge, and FIG. 13 is a plan sectional view of the developing cartridge. FIG. 14 is a front perspective view of the developing roller cover (a perspective view of the developing roller cover as viewed obliquely from the back when the developing roller cover is mounted), and FIG. 15 is a rear view of the developing roller cover. It is a perspective view.

  In this developing cartridge 30, as shown in FIG. 5, since the rubber roller 53 of the developing roller 38 is provided so as to be exposed rearward from the opening 94 of the housing 36, only the developing cartridge 30 is detached from the main body casing 2. In this state, the rubber roller 53 of the developing roller 38 may be damaged. Therefore, when only the developing cartridge 30 is detached from the main casing 2, a resin developing roller cover 134 covers the opening 94 of the housing 36 with respect to the developing cartridge 30 as shown in FIGS. 7 to 11. To be fitted.

The developing roller cover 134 is integrally provided with a longitudinal cover main body 135 and locking portions 136 and 137 that are provided at both ends in the longitudinal direction of the cover main body 135 and are locked to the developing cartridge 30. ing.
The cover main body 135 is formed in a substantially rectangular shape in front view extending in the axial direction of the developing roller 38 in a state where the developing roller cover 134 is mounted on the developing cartridge 30 (hereinafter simply referred to as “mounted state”). . The cover main body 135 is provided along the roller facing portion 138 facing the surface of the developing roller 38 (rubber roller 53) and the upper edge of the roller facing portion 138 in the mounted state, and the back support of the layer thickness regulating member 39. A second cover edge that is provided along an upper end edge 139 as a first cover edge facing the extension part 132 of the member 111 and a lower end edge of the roller facing part 138 and faces the reinforcing part 80 of the housing 36. And a side edge 141 that is provided along both side edges of the roller facing portion 138 and that faces the side wall 69 of the housing 36.

  As shown in FIG. 10, the roller facing portion 138 has a substantially rectangular shape in front view extending in the axial direction of the developing roller 38, and is formed so that the cross-sectional shape is a substantially arc shape. As shown in FIG. 12, at the both ends in the longitudinal direction of the roller facing portion 138, a packing material 142 (see FIG. 10) for packing the developing cartridge 30 is formed by bulging the portion below the center in the vertical direction outward. ) To form a receiving portion 143 having a substantially L-shaped cross section. By forming the receiving portion 143, a rib-like step extending in the vertical direction is formed between the receiving portion 143 and the roller facing portion 138.

As shown in FIGS. 12, 14, and 15, the upper edge portion 139 includes an upper front extension portion 144 that extends forward from the entire width of the upper edge of the roller facing portion 138 in the mounted state, and the upper front extension portion 139. An upper extending portion 145 extending upward from the tip edge of the portion 144 is integrally provided.
As shown in FIG. 9, the upper extension portion 145 has an upper guide portion 146 as a guide portion extending from the upper end edge toward the sandwiching portion 131 of the back support member 111 of the layer thickness regulating member 39 in the mounted state. Is provided.

  The upper guide portion 146 is formed in a flat trapezoidal shape in which both corners are cut off from an elongated rectangular shape extending along the upper edge portion 139 in plan view. In other words, the upper guide portion 146 is formed in a plate shape extending along the upper edge portion 139, and has a notch portion 147 having a triangular shape in plan view at both ends thereof. Further, the upper guide portion 146 has a length in the longitudinal direction slightly shorter than the interval between the both side walls 69 of the housing 36, and enters the space between the both side walls 69 in the mounted state, and the layer thickness regulating member It faces the extending portion 132 of the 39 back support members 111 from above.

As shown in FIGS. 12, 14, and 15, the lower end edge portion 140 includes a lower front extension portion 148 that extends forward from the entire width of the lower end edge of the roller facing portion 138 in the mounted state, and the lower front portion The extending portion 148 is integrally provided with a downward extending portion 149 extending downward from the lower surface of both ends in the longitudinal direction.
As shown in FIG. 15, the front end portion of the lower front extending portion 148 is formed narrower than the roller facing portion 138, and in the mounted state, the reinforcing upper wall 82 and the reinforcing front wall 85 of the reinforcing portion 80. Into the space defined by the reinforcing bottom wall 83 and both reinforcing side walls 84. As shown in FIG. 13, a notch 150 as a positioning portion into which the fitting portion 133 formed on the reinforcing bottom wall 83 is fitted is formed at the distal end portion of the lower front extension portion 148 in the mounted state. Has been.

The two downward extending portions 149 are arranged at intervals in the longitudinal direction of the lower front extending portion 148 and are each formed in a rectangular plate shape that is long in the longitudinal direction of the lower front extending portion 148. The lower extension portion 149 is provided with a lower guide portion 151 as a guide portion that extends forward under the reinforcing portion 80 of the housing 36 in the mounted state.
As shown in FIG. 11, the lower guide portion 151 is formed in a substantially trapezoidal shape when viewed from the bottom. The lower guide portion 151 faces the reinforcing portion 80 of the housing 36 from below in the mounted state.

  As shown in FIG. 15, the one locking portion 136 extends from the side edge portion 141 on one side in the longitudinal direction of the cover body portion 135 toward the outside in the longitudinal direction, and extends in a direction orthogonal to the longitudinal direction of the cover body portion 135. Two locking bases 152 provided at an interval, a locking extension 153 extending forward from the free end of each locking base 152 in the mounted state, and a free end of each locking extension 153 are connected. And a locking connecting portion 154 for integrally. The locking portion 136 has a U-shape when viewed from the outside in the longitudinal direction of the cover main body portion 135, and protrudes from the side wall 69 of the housing 36 between the locking extension portions 153. A locking hole 155 into which the end of the developing roller shaft 52 can be inserted is formed.

Further, as shown in FIG. 14, the other locking portion 137 extends from the side edge portion 141 on the other side in the longitudinal direction of the cover body portion 135 toward the outside in the longitudinal direction, and is orthogonal to the longitudinal direction of the cover body portion 135. Two locking bases 156 spaced in the direction, a locking extension 157 extending forward from the free end of each locking base 156 in the mounted state, and a free end of each locking extension 157 Are integrally provided with a locking connection portion 158 for connecting the two and an operation portion 159 extending obliquely outward from the locking connection portion 158. The locking portion 137 has a U shape when viewed from the outside in the longitudinal direction of the cover main body portion 135, and protrudes from the side wall 69 of the housing 36 between the locking extension portions 157. A locking hole 160 through which the end of the developing roller shaft 52 can be inserted is formed. In addition, the locking extension portion 157 and the operation portion 159 are each formed in a thin plate shape, and have flexibility that can be elastically deformed so as to open outward in the longitudinal direction of the cover main body portion 135.
4). Mounting of Developing Roller Cover FIGS. 16 and 17 are perspective views showing the mounting process of the developing roller cover. FIG. 16 is a perspective view of the developing cartridge as viewed obliquely from one side in the width direction, and FIG. It is the perspective view seen from the width direction other side slanting back.

  When attaching the developing roller cover 134 to the developing cartridge 30, first, the developing roller cover 134 is disposed so that the cover main body 135 faces the developing roller 38. The end (right end) of the developing roller shaft 52 protrudes from the right side wall 69 when the developing cartridge 30 is viewed from the rear in the locking hole 155 formed in the locking portion 136 of the developing roller cover 134. Is inserted, and the locking portion 136 is locked to the right end portion of the developing roller shaft 52.

  Next, the operation portion 159 of the locking portion 137 is pulled outward in the width direction (longitudinal direction of the cover main body portion 135), and the locking extension portion 157 and the operation portion 159 of the locking portion 137 are opened outward in the width direction. While being elastically deformed, the developing roller cover 134 is rotated using the locking portion 136 as a fulcrum so as to approach the surface of the developing roller 38 (rubber roller 53). At this time, the upper guide portion 146 of the developing roller cover 134 faces the extended portion 132 of the back support member 111 of the layer thickness regulating member 39 from above, and both lower guide portions 151 are the reinforcing portions 80 of the housing 36. The developing roller cover 134 is rotated by adjusting the inclination of the developing roller cover 134 with respect to the developing cartridge 30 so as to face from below. Accordingly, the upper guide portion 146 guides the upper end edge portion 139 of the cover main body portion 135 so as to be disposed along the extended portion 132 of the back support member 111. Further, the lower guide portions 151 guide the lower end edge portion 140 of the cover main body portion 135 so as to be disposed along the reinforcing portion 80 of the housing 36.

In the process in which the developing roller cover 134 is brought close to the developing roller 38, a fitting portion 133 formed on the reinforcing bottom wall 83 of the reinforcing portion 80 is formed at the tip of the lower front extending portion 148 of the developing roller cover 134. Thus, the developing roller cover 134 is positioned in the longitudinal direction of the opening 94.
When the locking hole 160 formed in the locking portion 137 faces the end portion (left end portion) of the developing roller shaft 52 protruding from the left side wall 69 in the rear view of the developing roller shaft 52 from the outside in the width direction. Then, the pull of the operation unit 106 is released. Then, due to the restoring force of the locking extension portion 157 and the operation portion 159 of the locking portion 137, the locking extension portion 157 and the operation portion 159 return to the original state, and the left end portion of the developing roller shaft 52 is inserted into the locking hole 160. As a result, the locking portion 137 is locked to the left end portion of the developing roller shaft 52. Thus, the mounting of the developing roller cover 134 to the developing cartridge 30 is achieved.
5). As described above, when the developing roller cover 134 is attached to the developing cartridge 30, the upper edge portion 139 of the cover main body portion 135 is caused to be connected to the back support member of the layer thickness regulating member 39 by the upper guide portion 146 of the developing roller cover 134. It is guided so that it may be arranged along the extending part 132 of 111. Thereby, it is possible to prevent the upper edge portion 139 from entering the opening 94 of the housing 36. Therefore, when the developing roller cover 134 is attached to the developing cartridge 30, it is possible to prevent the upper edge 139 from coming into contact with the surface of the developing roller 38 (rubber roller 53), and the surface of the developing roller 38 due to such contact can be prevented. Damage can be prevented.

  In addition, in this embodiment, in a state where the developing roller cover 134 is mounted on the developing cartridge 30, the upper guide portion 146 is opposite to the developing roller 38, that is, extends from the extending portion 132 of the back support member 111. Arranged above the portion 132. Therefore, the upper guide portion 146 can be prevented from entering the opening portion 94 of the housing 36 when the developing roller cover 134 is attached to the developing cartridge 30. As a result, when the developing roller cover 134 is attached to the developing cartridge 30, it is possible to prevent the upper guide portion 146 from contacting the surface of the developing roller 38, and to prevent damage to the surface of the developing roller due to such contact. be able to.

  In addition, when the developing roller cover 134 is attached to the developing cartridge 30, the lower end edge portion 140 of the cover main body portion 135 is disposed along the reinforcing portion 80 of the housing 36 by the lower guide portions 151 of the developing roller cover 134. To be guided. As a result, the lower edge 140 can be prevented from entering the opening 94 of the housing 36. Therefore, when the developing roller cover 134 is attached to the developing cartridge 30, it is possible to prevent the lower end edge portion 140 from coming into contact with the surface of the developing roller 38 (rubber roller 53), and the surface of the developing roller 38 due to such contact can be prevented. Damage can be prevented.

  Moreover, in this embodiment, in a state where the developing roller cover 134 is mounted on the developing cartridge 30, the lower guide portions 151 are opposite to the developing roller 38 across the reinforcing portion 80 of the housing 36, that is, the reinforcing portion. 80 below. Therefore, when the developing roller cover 134 is attached to the developing cartridge 30, both the lower guide portions 151 can be prevented from entering the opening portion 94 of the housing 36. As a result, when the developing roller cover 134 is attached to the developing cartridge 30, the lower guide portions 151 can be prevented from coming into contact with the surface of the developing roller 38, and the surface of the developing roller due to such contact can be prevented. Can be prevented.

Further, since the upper guide portion 146 enters between the side walls 69 of the housing 36 in the mounted state, the developing roller cover 134 can be prevented from rattling in the longitudinal direction of the opening portion 94.
Furthermore, since the notch portions 147 are formed at both longitudinal ends of the upper guide portion 146, the developing roller cover 134 is brought close to the developing cartridge 30 with the locking portion 136 locked to the developing roller shaft 52 as a fulcrum. Sometimes, it is possible to avoid that both end portions in the longitudinal direction of the upper guide portion 146 come into contact with both side walls 69. Therefore, the upper guide portion 146 can smoothly enter between the side walls 69 of the housing 36.

  Further, in a state where the developing roller cover 134 is mounted on the developing cartridge 30, the fitting portion 133 formed on the reinforcing bottom wall 83 of the reinforcing portion 80 is a tip of the lower front extending portion 148 of the developing roller cover 134. The developing roller cover 134 is positioned in the longitudinal direction of the opening 94 by fitting into a notch 150 formed in the portion. Therefore, it is possible to prevent the developing roller cover 134 from rattling in the longitudinal direction of the opening 94.

In addition, reliable positioning in the longitudinal direction of the developing roller cover 134 can be achieved with a simple configuration in which the notch 150 is formed in the lower front extending portion 148 of the developing roller cover 134.
Further, since the notch 150 is formed at a position offset toward the locking portion 136 which is a fulcrum when mounted, in the process of bringing the developing roller cover 134 closer to the developing cartridge 30, the reinforcing bottom wall of the reinforcing portion 80 is provided. 83 is fitted into a notch 150 formed at the tip of the lower front extension 148 of the developing roller cover 134, whereby the developing roller cover 134 is opened to the opening 94. In the longitudinal direction. Therefore, it is possible to prevent the developing roller cover 134 from being displaced in the longitudinal direction of the opening 94. Therefore, it is possible to prevent the end portion in the longitudinal direction of the developing roller cover 134, that is, the locking portion 137 from entering the opening portion 94, and prevent damage to the surface of the developing roller 38 due to the contact of the locking portion 137. Can do. That is, when the developing roller cover 134 is attached to the developing cartridge 30, the surface of the developing roller 38 can be prevented from being damaged by the contact of the engaging portion 137 of the developing roller cover 134. Can be prevented from rattling in the longitudinal direction of the opening 94. Further, the positioning tolerance in the process of mounting the developing roller cover 134 can be reduced by shifting the notch 150 toward the locking portion 136 that is a fulcrum when the developing roller cover 134 is mounted.

  Further, since the locking portion 137 is flexible enough to be elastically deformed, when the locking portion 137 is locked to the developing roller shaft 52, the locking portion 137 can be easily deformed. . For this reason, the locking portion 137 can be easily locked to the developing roller shaft 52, and the labor for mounting the developing roller cover 134 to the developing cartridge 30 can be reduced.

  Furthermore, since the locking portions 136 and 137 are locked to the end portion of the developing roller shaft 52, it is necessary to separately provide a member for locking the locking portions 136 and 137 in the housing 36 of the developing cartridge 30. Absent. Therefore, the number of parts of the developing cartridge 30 can be reduced, and the configuration of the developing cartridge 30 can be simplified. By engaging the engaging portion 136 with the developing roller shaft 52, the developing roller cover 134 is likely to swing around the developing roller shaft 52 when the developing roller cover 134 is mounted. In addition, since the lower guide portion 151 is provided, it is possible to prevent the upper end edge portion 139 and the lower end edge portion 140 of the cover main body portion 135 from entering the opening portion 94 of the housing 36.

  Further, since the cover main body 135 of the developing roller cover 134 is provided with the roller facing portion 138 having an arcuate cross section, the strength of the cover main body 135 can be increased. Further, since the receiving portions 143 are formed to bulge at both longitudinal ends of the roller facing portion 138 and a step is formed between the receiving portion 143 and the roller facing portion 138, the strength of the cover main body portion 135 is increased. Can be further increased.

Furthermore, when the developing cartridge 30 is packed, the receiving cartridge 143 is received by the packing material 142, so that the developing cartridge 30 can be packed in a stable state.
The receiving portion 143 may be provided only at one end in the longitudinal direction of the roller facing portion 138. However, the receiving portion 143 is provided at both ends in the longitudinal direction of the roller facing portion 138 so that the developing cartridge 30 is in a more stable state. In addition, the strength of the cover main body 135 can be further increased.

  The developing cartridge 30 is provided with a developing roller cover 134 that can prevent the upper edge portion 139 and the lower edge portion 140 from contacting the surface of the developing roller 38 when the developing cartridge 30 is attached. When the developing roller cover 134 is attached, it is possible to prevent the surface of the developing roller 38 from being damaged due to the contact between the upper edge portion 139 and the lower edge portion 140 of the developing roller cover 134.

1 is a side sectional view showing an embodiment of a laser printer provided with a developing cartridge of the present invention. FIG. 2 is a side sectional view of the process cartridge shown in FIG. 1. FIG. 3 is a perspective view of the developing cartridge as viewed from obliquely behind. FIG. 4 is a rear view of the developing cartridge shown in FIG. 3. FIG. 4 is a side view of the developing cartridge shown in FIG. 3. FIG. 4 is a bottom view of the developing cartridge shown in FIG. 3. FIG. 6 is a perspective view of the developing cartridge with the developing roller cover attached, as viewed from one side obliquely rearward in the width direction. FIG. 8 is a perspective view of the developing cartridge shown in FIG. 7 as viewed from the diagonally rear side on the other side in the width direction. FIG. 8 is a plan view of the developing cartridge shown in FIG. 7. FIG. 8 is a rear view of the developing cartridge shown in FIG. 7. FIG. 8 is a bottom view of the developing cartridge shown in FIG. 7. FIG. 8 is a side sectional view of the developing cartridge shown in FIG. 7. FIG. 8 is a plan sectional view of the developing cartridge shown in FIG. 7. It is a front perspective view of a developing roller cover. FIG. 15 is a rear perspective view of the developing roller cover shown in FIG. 14. FIG. 10 is a perspective view showing a process of attaching the developing roller cover, as seen from the diagonally rear side on the one side in the width direction of the developing cartridge. FIG. 17 is a perspective view showing a process of attaching the developing roller cover, and is a perspective view of the developing cartridge shown in FIG.

30 Developing cartridge 36 Housing 38 Developing roller 39 Layer thickness regulating member 52 Developing roller shaft 69 Side wall 80 Reinforcing part 94 Opening part 133 Fitting part 134 Developing roller cover 135 Cover body part 136 Locking part 137 Locking part 138 Roller facing part 139 Upper edge portion 140 Lower edge portion 142 Packing material 143 Receiving portion 146 Upper guide portion 147 Notch portion 150 Notch 151 Lower guide portion

Claims (10)

A casing in which a longitudinal opening is formed, and a part of the casing is disposed in the opening so as to be exposed to the outside of the casing, and both end portions of the shaft project outside the casing. A developing cartridge comprising a developing roller supported by the housing and a layer thickness regulating member for regulating the layer thickness of the developer carried on the surface of the developing roller ;
A reinforcing portion extending along the longitudinal direction of the opening on one side of the housing in a direction perpendicular to the longitudinal direction with respect to the opening.
A developing roller cover that is detachably attached to the housing and that protects the surface of the developing roller in a mounted state attached to the housing;
The layer thickness regulating member is
A blade body facing the developing roller, and a support member that is bent in a substantially L-shaped cross section, extends in the axial direction of the developing roller, and supports the blade body on the housing;
The support member includes an extending portion extending toward the outside of the housing,
The developing roller cover is
In the mounted state, a cover main body disposed opposite to the surface of the developing roller and extending in the longitudinal direction of the opening;
The cover body portion extends from both ends in the longitudinal direction in a direction perpendicular to the longitudinal direction, and is opposed to each other with a gap larger than the gap between the outer side surfaces of the casing in the longitudinal direction, and the mounted state A locking portion locked to an end of the shaft protruding from the housing;
A first cover edge that extends in the longitudinal direction of the cover main body and is disposed along the extended portion in the mounted state ;
A second cover edge that extends in the longitudinal direction of the cover main body, is disposed along the reinforcing portion in the mounted state, and faces the first cover edge in a direction orthogonal to the longitudinal direction of the cover main body; ,
Wherein provided on the first cover edge, said at mounting with respect to the casing, such that the first cover edge are provided along the extending portion of the support member extending in the longitudinal direction at the periphery of the opening A first guide for guiding the edge of the first cover ;
Provided at both ends in the longitudinal direction of the second cover edge so that the second cover edge is disposed along the reinforcing portion extending in the longitudinal direction at the periphery of the opening when mounted on the housing. , and a second guide portion for guiding said second cover edge,
One of the locking portions is integrally provided with an operation portion that is operated when the developing roller cover is attached to the housing, and has flexibility that can be elastically deformed so as to open outward in the longitudinal direction. A developing cartridge characterized by the above.   2. The developing cartridge according to claim 1, wherein the guide portion provided on the edge of the first cover is disposed on the opposite side of the developing roller with the opening edge in the mounted state. . The housing includes two sidewalls facing each other across the opening in the longitudinal direction of the opening,
The developing cartridge according to claim 1, wherein the guide portion provided at the edge of the first cover enters between the two side walls in the mounted state.   The guide portion provided at the edge of the first cover extends along the edge of the first cover, and a notch for avoiding interference with the side wall is formed at both ends in the longitudinal direction. The developing cartridge according to claim 3, wherein the developing cartridge is characterized in that:   5. The developing cartridge according to claim 1, further comprising a positioning portion for positioning the developing roller cover in a longitudinal direction of the opening in the mounted state. 6. One of the locking portions has flexibility,
The developing cartridge according to claim 5, wherein the positioning portion is provided at a position offset to the opposite side to the flexible locking portion. The opening edge includes a fitting portion extending in a direction perpendicular to the longitudinal direction of the opening,
The positioning portion, the is formed by an incision in the cover edge, characterized in that fitting the fitting portion in the mounted state, the developing cartridge according to claim 5 or 6. The developing cartridge according to any one of claims 1 to 7 , wherein the cover main body portion includes a roller facing portion having an arcuate cross section when cut along a plane orthogonal to the longitudinal direction thereof. 9. The apparatus according to claim 8 , further comprising a receiving portion that is bulged from the cover main body and is received by a packing material for packing the developing cartridge when the developing cartridge is packed in the mounted state. The cartridge described. The developing cartridge according to claim 9 , wherein the receiving portion is formed at each of both ends in the longitudinal direction of the cover main body portion.

Images