JP2002214919A - Developing container, processing cartridge and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the reduction of the number of parts, the simplification of assembly into a developing container, the improvement of positioning accuracy and the stabilization of positioning. SOLUTION: This device possesses walls 31 and 32 arranged at both ends in a longitudinal direction and a magnet positioning member 35 fit in one end of a sleeve unit 22 having a developing magnet 23, and one end of the developing magnet 23 is fit and supported in/by one wall 31, and a mounting hole into which the magnet positioning member 35 is inserted is formed on the other wall 32, and the positioning of the sleeve unit 22 in a radial direction is performed by inserting the magnet positioning member 35 in the mounting hole and fitting it in the other end of the developing magnet, and also the magnet positioning member presses the developing magnet 23, so that the positioning of the sleeve unit 22 in a thrust direction is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus and a process cartridge which can be attached to and detached from a main body of the apparatus, and more particularly to the positioning of a sleeve unit used for development.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic image process, an electrostatic latent image formed on a photosensitive drum serving as an image carrier is developed with a developer, transferred to a sheet, and then fixed. Thus, an image is formed.
To develop such an electrostatic latent image, using a developer having magnetism, a developing sleeve that covers a fixedly supported developing magnet is arranged, and by rotating the developing sleeve, a predetermined amount of the developer is placed near the image carrier. It is carried out by transferring and transferring.

A conventional support structure of a sleeve unit having such a developing sleeve and a developing magnet will be described with reference to FIGS. FIG. 7 is a diagram illustrating a conventional developing container during assembly, and FIG. 8 is a diagram illustrating a conventional developing container after assembly.

In FIG. 7, a cover such as side covers 31 and 36 is provided at both ends in the longitudinal direction of the developing container 100, and a portion for supporting the flange of the developing sleeve 22 is formed on the cover. In general, a structure in which the developing sleeve 22 and the like are supported by being attached is used.

[0005]

However, since the positioning for supporting the developing magnet 23 with respect to the developing container is performed by the side covers 31 and 36 attached to the developing container, the number of components tends to increase.

Further, since a gap is formed between the side covers 31, 36 for positioning the developing magnet 23 and the developing magnet 23, the magnet may not be stable in the longitudinal direction by the gap.

The developing sleeve 22 and the developing magnet
As a method for stabilizing 23 in the longitudinal direction, a configuration in which it is urged by using a spring or the like may be considered, but the number of parts may further increase.

Accordingly, the present invention reduces the number of components for supporting the developing sleeve and the like, particularly the developing magnet, in the developing container, thereby simplifying the assembly to the developing container, improving the positioning accuracy, and stabilizing the positioning. An object of the present invention is to provide an intended developing container and a process cartridge or an image forming apparatus provided with the same.

[0009]

In order to solve the above-mentioned problems, a typical configuration of a developing container, a process cartridge and an image forming apparatus according to the present invention is a developing container used in an electrophotographic system, which has two longitudinal ends. And a sleeve unit having a developing sleeve made of a hollow non-magnetic metal, a developing magnet included in the developing sleeve, and a magnet positioning member fitted to one end of the developing magnet. An interval between the walls is wider than a length of the sleeve unit, and one end of the developing magnet is fitted and supported by one of the walls, and a mounting hole for inserting the magnet positioning member into the other wall is provided. Is formed, and the magnet positioning member is inserted into the mounting hole and fitted to the other end of the developing magnet. Serial to position in the radial direction of the sleeve unit, further wherein the magnet positioning member is characterized in that the positioning of the thrust direction of the sleeve unit by energizing the magnetic developing.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a developing container, a process cartridge provided with the same, and an image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is an overall configuration diagram of the image forming apparatus. In the following description, the longitudinal direction is a direction perpendicular to the sheet conveying direction and parallel to the sheet. Also, left and right refer to left and right as viewed from the sheet conveyance direction. Further, “above the process cartridge” means above the process cartridge in the mounted state.

(Image Forming Apparatus) An image forming apparatus 1 shown in FIG. 1 has an image forming section 3 for forming a toner image on a photosensitive drum 6 serving as an image carrier, and an intermediate transfer for temporarily transferring the formed toner image. The belt unit 7, a secondary transfer roller 9, which is a transfer unit for secondary-transferring the toner image on the intermediate transfer belt unit 7 to the sheet S, and feeding the sheet S between the intermediate transfer belt 7 a and the secondary transfer roller 9 It has a feeding unit, a fixing device 15 for fixing the toner image, and a discharging unit.

A feeding cassette 10 arranged at the lower part of the apparatus is detachably mounted on the apparatus main body, and a plurality of sheets S are stacked and stored. The sheet S is, for example, a recording paper, an OHP sheet, a cloth, or the like. Pickup roller
The sheet S fed from the feeding cassette 10 by the separation roller 11 is separated and fed one by one by a separation roller pair 12, and a pair of registration rollers serving as sheet conveyance means is conveyed by a pair of conveyance rollers 13.
Sent to 14. When the sheet S is conveyed, the registration roller pair 14 has stopped rotating, and the skew of the sheet S is corrected by being hit against the nip.

In the case of a four-drum full-color system, the process cartridge 5 including the photosensitive drum 6 is arranged in parallel with four of yellow, magenta, cyan, and black as shown in FIG. Each process cartridge 5Y, 5M, 5C,
Optical scanning systems 2Y, 2M, 2C, 2
After BK is provided, an electrostatic latent image for each color is formed by an image signal, and then developed to form a toner image. The transfer rollers 8Y, 8M, 8C, and 8BK transfer the respective color toner images onto the intermediate transfer belt 7a, which rotates in the direction indicated by the arrow, in a superimposed manner.

Thereafter, the sheet S is sent to the secondary transfer roller 9 at a predetermined timing by the registration roller pair 14, and the toner image on the intermediate transfer belt 7a is transferred onto the sheet S. After heat and pressure are applied by the fixing device 15, the sheet S is conveyed to a discharge roller pair 17 by a conveyance roller pair 16, and is discharged and stacked on a discharge tray 18 which is a discharge means provided at an upper portion of the apparatus. .

The image forming units 3Y, 3M, 3C, 3BK
Are the process cartridges 5Y, 5M, 5C, 5
BK and toner containers 4Y, 4M, 4C and 4BK. Since the configuration of each process cartridge is the same, the process cartridge 5Y will be described.

(Process Cartridge) Referring to FIG.
The process cartridge according to the present embodiment will be described. FIG. 2 is a configuration diagram of the process cartridge. As shown, the process cartridge 5 includes a photosensitive drum 6.
, Charging means, exposing means, developing means, and a transfer opening are arranged around the periphery of the device. In the present embodiment, a two-component developer including a magnetic carrier powder and a toner is used as the developer.

The charging means is a magnetic brush charger 20 using a magnetic carrier. The magnetic brush charger 20 has a magnet 20b fixed inside a hollow cylindrical charging roller 20a rotatably supported. Further, the toner remaining on the photosensitive drum 6 after the end of the transfer is taken into the magnetic brush charger 20 rotating in the direction of the arrow in FIG.

In the present embodiment, the developing means 21 is a method of developing with a two-component developer in a contact state (two-component non-contact development).
The figure shows a configuration for two-component magnetic brush development. The developing sleeve 22 has a hollow cylindrical shape and is rotatably supported. In the developing sleeve 22, a fixed developing magnet 23 is provided. The developing sleeve 22 rotates in the same direction as the photosensitive drum 6, and the peripheral surface moves in a direction opposite to the moving direction of the peripheral surface of the photosensitive drum 6. The photosensitive drum 6 and the developing sleeve 22 are not in contact with each other and are spaced apart by about 0.2 to 1.0 mm, and are set so that the developer can be developed in a state of contact with the photosensitive drum 6. The image forming apparatus according to the present embodiment has an image forming capacity of 20 to 30 sheets / min, the rotation speed of the photosensitive drum 6 is about 75 rpm, and the developing sleeve 2
The rotation speed of 2 is set to about 230 rpm.

A developer composed of a mixture of a magnetic carrier and a toner is supplied from a toner container 4 (see FIG. 1) to a developing means 21. The inside of the casing of the developing means 21 is partitioned by partitions 24 except for both ends, and stirring screws 25a and 25b for transporting the developer in opposite directions are arranged on both sides of the partitions 24. The developer dropped from the toner container 4 drops to one end of the stirring screw 25a and is stirred while being transported in the longitudinal direction. Then, at the other end side, it moves to the stirring screw 25b side through the portion without the partition wall 24, is stirred while being transported again to the opposite side in the longitudinal direction, and circulates to the stirring screw 25a side through the portion without the partition wall 24. I do. The stirring screws 25a and 25b are used for the developing sleeve 22 rotating at a high speed.
Both rotate at about 330 rpm to supply the developer.

Here, the developing process of developing the electrostatic latent image formed on the photosensitive drum 6 by the two-component magnetic brush method using the developing means 21 and the circulation system of the developer will be described. First, the developer conveyed by the stirring screw 25b is pumped to the surface of the developing sleeve 22 by the magnetic pole of the developing magnet 23. With the rotation of the developing sleeve 22, the thickness is regulated by the developing blade 26 arranged perpendicular to the developing sleeve 22, and a thin film of the developer is formed on the developing sleeve 22. When the developer on which the thin film is formed is conveyed to the developing main electrode, a spike is formed by a magnetic force. The developer formed in the spike shape is the photosensitive drum 6
Is developed from the developing sleeve 22 and then returned from the developing sleeve 22 to the developing container 27 by a repulsive magnetic field.

A DC voltage and an AC voltage are applied to the developing sleeve 22 from a power source (not shown). In general, in the two-component developing method, when an AC voltage is applied, the developing efficiency is increased, and the quality of the image is high. However, on the contrary, there is a problem that fogging is easily generated. For this reason, a potential difference is normally provided between the DC voltage applied to the developing sleeve 22 and the surface potential of the photosensitive drum 6 to prevent toner from adhering to the non-image area during development.

(Developing Container) The developing container according to the present embodiment will be described with reference to FIGS. 3 is a perspective view of the developing container in the vicinity of the developing sleeve, FIG. 4 is an external perspective view of the developing container, FIG. 5 is a sectional view of the developing container in the course of assembly, and FIG. 6 is a sectional view of the developing container after the assembly.

First, the sleeve unit will be described.
The developing sleeve 22 is a metal sleeve cylinder, and a magnet shaft 23a which is an end of the developing magnet 23 contained therein.
Are exposed at both ends. Further, as shown in FIG. 4, spacers 28a and 28b are provided at both ends of the developing sleeve 22 for regulating a gap between the surface of the developing sleeve and the photosensitive drum 6, and oscillating for positioning the developing sleeve 22 in the developing container 27 outside thereof. The arm 29 is inserted and arranged. Further, on the driving side, a sleeve gear 30 for driving the developing sleeve 22 is inserted and arranged.
These are collectively called a sleeve unit.

Next, the structure for supporting the developing sleeve will be described. As shown in FIG. 4, the developing container 27 is provided with walls protruding at both ends in the longitudinal direction. The wall on the drive transmission side is referred to as a contact-side developing container wall 31, and the other side is simply referred to as a developing container wall 32. . The distance between the two developing container walls is wider than the entire length of the sleeve unit. As shown in FIG. 4, the sleeve unit is attached by moving in the direction of the arrow so as not to hit the two developer container walls. At this time, the swing arm 29 is temporarily mounted so as to engage with the swing arm mounting groove 33 of the developing container 27. The developing sleeve 22 is pressed against the developing end seal 34 affixed to the developing container 27, and the axial center of the developing sleeve 22 and the magnet shaft support hole 31a of the abutting developing container wall 31 are provisionally positioned substantially coaxially.

FIG. 5 shows a provisionally determined state of the sleeve unit. The sleeve gear 30 includes the developing sleeve 22 and the magnet shaft 23.
The state of a is shown by a broken line so that it can be easily understood. In the temporary positioning state, the swing arm 29 and the sleeve gear 30 are positioned longitudinally. Drive side spacer
Reference numeral 28b is disposed between the swing arm 29 positioned in the swing arm mounting groove 33 and the step between the developing sleeve 22 and a gap for the movement allowance so that the developing sleeve 22 can move.
On the other hand, the spacer 28a on the non-driving side is almost in contact with both the step of the developing sleeve 22 and the swing arm 29.

Next, the sliding movement of the developing sleeve 22 and the magnet 23 will be described. As shown in FIG. 6, when the developing sleeve 22 is slid to the driving side in the longitudinal direction with respect to the developing container 27 and the swing arm 29, the magnet shaft 23a and the magnet shaft support hole 31a are coaxially arranged as described above. Therefore, the magnet shaft 23a is easily fitted into the magnet shaft support hole 31a of the abutting side developing container wall 31. When the developing sleeve 22 is slid, the spacer 28b on the driving side comes into close contact between the swing arm 29 and the step of the developing sleeve 22.

On the other hand, the spacer 28a on the non-drive side has a gap between the swing arm 29 and the step of the developing sleeve 22.
Since the spacer 28a on the non-driving side is movable in the longitudinal direction, a member for positioning the spacer 28a in the longitudinal direction is disposed after the sleeve unit is assembled. In this embodiment, a sleeve cover (not shown) for protecting the developing sleeve 22 is attached after the sleeve unit is attached, and the spacer 28a is positioned by a rib provided on the sleeve cover.

Next, the magnet positioning member 35 for positioning the developing magnet 23 will be described. The magnet positioning member 35 is located on the non-drive side,
Supports the magnet shaft 23a of the developing container.
Inserted from outside 32.

The magnet positioning member 35 is fitted to the sleeve support member mounting hole 32a of the developing container wall 32 so that the developing container 27 and the magnet shaft 23a are arranged coaxially, and then fitted to the magnet shaft 23a. Like this magnet shaft
The driving side of 23a is supported by the magnet shaft support hole 31a of the developing container 27, and the non-driving side is supported by the developing container 27 via a magnet positioning member 35 coaxial.
The positioning accuracy a in the radial direction with respect to the developing container 27 can be significantly improved.

The end of the magnet shaft 23a is provided with a D-cut.
D-cuts 35a are also formed in the 35 fitting holes. A rotation restricting rib 35b is formed on the outer periphery of the magnet positioning member 35, and a rotation restricting groove 32b is formed correspondingly on the inner periphery of the sleeve support member mounting hole 32a. Therefore, when these are fitted together, when the magnet shaft 23a is supported by the magnet positioning member 35, the rotation of the magnet shaft 23a is restricted and fixed to the developing container wall 32.

Further, the magnet positioning member 35 is provided with three flexible ribs 35c, which are elastic members, and is provided so as to protrude on the opposite side of the developing sleeve 22. Then, the magnet positioning member 35 is attached to the sleeve support member mounting hole 32.
a, the side rib 36 is fixed to the developing container 27 from the outside of the developing container wall 32 so that the flexible rib 35
c is bent and the magnet positioning member 35 is moved to the magnet shaft 23.
a in the thrust direction. Magnet shaft
Since 23a is fixed by abutting on the magnet shaft support hole 31a of the abutment side developing container wall 31, it can be positioned with high accuracy based on the magnet shaft support hole 31a by being urged. Further, by positioning by biasing, the positioning can be stably maintained without shifting even when the device is used continuously.

Although the present embodiment has been described using the developing container provided in the process cartridge, the present invention is also applicable to a developing container directly attached to an image forming apparatus without using a process cartridge. Similar effects can be obtained.

[0033]

As described above, in the developing container, the process cartridge and the image forming apparatus according to the present invention, the distance between the walls at both ends of the developing container is set to be wider than the length of the sleeve unit having the developing sleeve and the developing magnet. , Attach one end of the magnet shaft directly to the container,
By supporting the other end by urging it in the thrust direction by the magnet positioning member, the number of parts for supporting the sleeve unit can be reduced, and the assembly of the sleeve unit into the developing container is simplified and Thus, production costs can be reduced.

Further, by performing the positioning in the thrust direction by urging, the positioning accuracy in the thrust direction can be improved and the positioning can be stabilized, so that the developing performance by the developing magnet can be stably provided. Can be.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an image forming apparatus.

FIG. 2 is a configuration diagram of a process cartridge.

FIG. 3 is a configuration diagram of a main part near a developing sleeve.

FIG. 4 is an external perspective view of a developing container.

FIG. 5 is a cross-sectional view of the developing container being assembled.

FIG. 6 is a sectional view of the developing container after assembly.

FIG. 7 is a view showing a conventional developing container during assembly.

FIG. 8 is a view showing a conventional developing container after assembly.

[Explanation of symbols]

 S: Sheet 1: Image forming apparatus 2: Optical scanning system 3: Image forming unit 4: Toner container 5: Process cartridge 6: Photosensitive drum 7: Intermediate transfer belt unit 7a: Intermediate transfer belt 8: Transfer roller 9: Secondary Transfer roller 10… Supply cassette 11… Pickup roller 12… Separation roller pair 13… Transport roller pair 14… Registration roller pair 15… Fixer 16… Transport roller pair 17… Discharge roller pair 18… Discharge tray 20… Magnetic brush charger 20a ... charging roller 20b ... magnet 21 ... developing means 22 ... developing sleeve 23 ... developing magnet 23a ... magnet shaft 24 ... partition wall 25 ... stirring screw 26 ... developing blade 27 ... developing container 28 ... spacer 29 ... swing arm 30 ... sleeve gear 31… abutting side developer container wall 31a… magnet shaft support hole 32… developer container wall 32a… sleeve support member mounting hole 32b … Rotation restricting groove 33… Swing arm mounting groove 34… Development end seal 35… Magnet positioning member 35a… D cut 35b… Rotation restricting rib 35c… Flexible rib 36… Side holder

Continuation of the front page (72) Inventor Naofumi Horikawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Takato Ueno 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F term (reference) 2H031 AC08 AC18 AC19 BA04 EA03 FA01 FA05 2H077 AD06 BA08 EA03 GA13

Claims (7)

[Claims] 1. A developing container for use in an electrophotographic system, comprising: a sleeve disposed at both ends in a longitudinal direction; a developing sleeve made of a hollow non-magnetic metal; and a developing magnet included in the developing sleeve. And a magnet positioning member fitted to one end of the developing magnet, wherein the distance between the walls is greater than the length of the sleeve unit, and one end of the developing magnet is fitted and supported by one of the walls. And a mounting hole in which the magnet positioning member can be inserted is formed in the other wall, and the magnet positioning member is inserted into the mounting hole and fitted to the other end of the developing magnet, thereby radially connecting the sleeve unit. Direction, and the magnet positioning member biases the developing magnet. Developer container, characterized in that the positioning of the thrust direction of the sleeve unit by. 2. The developing container according to claim 1, wherein the magnet positioning member integrally has an elastic member for urging the developing magnet. 3. The developing container according to claim 2, further comprising a cover provided outside said wall to support said magnet positioning member via said elastic member. 4. The developing container according to claim 1, wherein the magnet positioning member has a rotation restricting portion for the developing magnet. 5. The developing container according to claim 1, wherein the magnet positioning member has a rotation restricting portion for a mounting hole provided in the wall. 6. A process cartridge comprising: an image carrier for carrying at least a latent image; and a developing container according to claim 1. Description: 7. A sheet conveying means for conveying a sheet, an image carrier for carrying a latent image, a developing container according to claim 1, and an image on the image carrier for the sheet. An image forming apparatus, comprising: a transfer unit that transfers the image to the image forming apparatus.