JPH10339999A - Developing device, process cartridge and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress and prevent the slipping of a developer in the longitudinal direction of a developer carrier and further, the leakage of the developer caused by impact, etc. SOLUTION: In the opening part of a developing container 30, a composite sleeve 31 provided with a magnet roller 32 inside and consisting of a nonmagnetic member and a magnetic member are arranged. A magnet seal member 34 for regulating the movement of toner is arranged in a noncontact state with a developing sleeve 31, on the outer periphery on the side of the developing container 30, of the composite sleeve 31. Further, the magnetic member of the composite sleeve 31 is arranged in the vicinity of the magnet seal member 34 and a magnetic field is generated between the magnet seal member 34 and the magnetic member, to form the napping of a magnetic brush between the magnet seal member 34 and the magnetic member by the working of the magnetic field.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device, a process cartridge and an image forming apparatus for developing an image with a magnetic developer when an image is formed by an electrophotographic recording method or the like.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus for forming an image by an electrophotographic recording method or the like, an electrophotographic photosensitive member as an image carrier and a process means acting on the electrophotographic photosensitive member are integrally formed as a cartridge. In some cases, a process cartridge system in which this cartridge is configured to be detachable from the image forming apparatus main body is employed.

According to this process cartridge system,
The maintenance of the main members of the apparatus can be performed by the user himself without replacing the service cartridge by exchanging the process cartridge, so that the operability can be remarkably improved. Therefore, the process cartridge system is widely used in image forming apparatuses such as printers.

In a developing device which is a developing means incorporated in such a process cartridge, a developer image carrier capable of transporting the developer to a developing area for developing an electrostatic latent image by rotating while carrying the developer is provided. Sealing members for preventing the developer from flowing out of the developing area are provided at both ends of the developing sleeve.

[0005] As a seal member for preventing the developer from flowing out, an elastic material such as felt or foamed rubber is widely used. FIGS. 17 and 18 show examples in which a seal member is used. FIG. 17 is a schematic configuration diagram showing a main part of a developing device incorporated in a conventional process cartridge, and FIG. 18 is a partial cross-sectional explanatory view showing the vicinity of a longitudinal end of the developing device.

As shown in FIG. 17, a developing sleeve 310 for carrying a developer has a magnet roller 320 disposed therein. Further, as shown in FIG. 18, the developing sleeve 310 is connected to the developing container 3 via a sleeve bearing 350 provided at a predetermined position of the developing container 300 containing the developer.
00, the developer supplied from the developing container 300 adheres to the surface of the developing sleeve 310 by the magnetic force of the magnet roller 320, and the layer thickness is increased by the developing blade 330 abutting on the developing sleeve 310. After being regulated to a predetermined thickness, with the rotation of the developing sleeve 310, the developing sleeve 310 is conveyed to a developing area which is a position facing a latent image on a photosensitive drum arranged at a position facing the developing sleeve 310,
The developer conveyed to the development area adheres to the latent image to perform development.

At this time, an elastic seal member 360 is attached to the developing container 300 side of the developing sleeve 310 mounted on the developing container 300 at both ends in the longitudinal direction outside the developing region of the developing sleeve 310. The elastic seal member 360 is formed in a substantially arc-shaped cross section along the outer peripheral surface of the developing sleeve 360 by, for example, felt or foamed rubber.
0 by pressing against the outer peripheral surface of the developing sleeve 31.
The developer is prevented from flowing out from the surface of No. 0 to the end in the longitudinal direction.

In the developing device using the elastic seal member having the above-described structure, the elastic seal member 360 is in pressure contact with approximately half of the outer peripheral surface of both ends of the developing sleeve 310, so that the developing sleeve that rotates during the developing operation is operated. There is a problem that the load of the developing sleeve 310 is large, the elastic seal member 360 is deteriorated by the contact with the developing sleeve 310 and the sealing performance is deteriorated, and the gap between the developing sleeve 310 and the elastic seal member 360 is slightly increased. In some cases, however, the toner may enter, and as a result, the torque may increase, or the fluctuation of the torque may increase, resulting in rotation unevenness, which may adversely affect image formation.

Therefore, in order to solve these problems, a developing sleeve is provided at a position where an elastic seal member is provided.
Instead of the elastic seal member, a magnet seal member is arranged at predetermined intervals along the outer peripheral surfaces of both ends of the developing sleeve,
There has been proposed a method for preventing the developer from flowing out.

FIG. 19 is a schematic configuration diagram showing a developing device using a conventional magnet seal member. Developing sleeve 310
The magnet seal members 370 provided at both ends are magnets formed in a substantially arc-shaped cross section along the outer periphery of the developing sleeve 310, and NS poles are magnetized on the inner peripheral surface thereof into multiple magnetic poles. The magnet seal member 370 has a magnet roller 3 inside thereof.
At both ends of the developing sleeve 310 having the gap 20, the developing sleeve 310 is disposed at a predetermined gap g from the outer peripheral surface on the side of the developing container, and is attached to the developing container together with the developing sleeve 310 while maintaining the gap g. The magnet seal member 370
The magnetic pole is provided on the inner peripheral surface of the magnet seal member at a position facing the magnetic pole of the magnet roller.

The magnet seal member 370 is connected to the magnet roller 320 in the developing sleeve 310 and the magnet seal member 370.
And a magnetic brush that restrains the developer between the end of the developing sleeve and the magnet seal member to form a seal portion between the end of the developing sleeve and the magnet seal member. By blocking the moved developer, the developer can be prevented from flowing out from the end of the developing sleeve.

When the above-mentioned magnet seal is used, the developing sleeve and the magnet seal member are kept out of contact with each other, and the rotational torque of the developing sleeve becomes extremely small. Therefore, the noise motor is small and inexpensive. In addition, the fluctuation of the rotation torque is small, the uneven rotation of the developing sleeve and the photosensitive drum hardly occurs, and there is no wear of the magnet seal member. Therefore, the use thereof is semi-permanent, and the device can be recycled.

[0013]

However, in the case where the above-mentioned conventional magnet seal member is used, there is a portion where the magnetic brush is not sufficiently raised due to the lines of magnetic force between the magnet inside the developing sleeve and the magnet seal member. There is a problem that the sealability of the agent may not be sufficient. In particular, the magnetic brush between the magnetic poles of both the magnet and the magnet seal member in the developing sleeve is likely to have insufficient spikes,
There is a problem that the sealing property between the magnetic poles is inferior to the sealing property of the portion where the magnetic poles face each other.

If the magnet poles of the magnet and the magnet sealing member in the developing sleeve are opposite to each other, the magnetic brush does not sufficiently form the ears of the magnetic brush due to the action of the repelling magnetic field, and the developer leaks. There was a problem that can not be prevented. In such a case, there is a possibility that the developer may leak from a portion of the magnetic brush where ears are insufficient due to an impact when the user installs the process cartridge. Further, when the developing device is operated, the developer may pass through a portion of the magnetic brush where the ears are insufficient, and there is a concern about the sealing property. Furthermore, when the magnet in the developer carrier rotates, the rotation of the magnet changes the polarity of the magnetic pole facing the magnetic pole of the magnet seal member, or changes the position between the magnetic poles, so that the magnetic brush stand is not used. It was easy to become unstable, and the sealability was uneasy.

Therefore, the present invention can suppress and prevent the developer from passing through the developer carrier in the longitudinal direction.
An object of the present invention is to provide a developing device, a process cartridge, and an image forming apparatus that can suppress and prevent leakage of a developer caused by an impact or the like.

Further, according to the present invention, even when the magnet in the developer carrier rotates, it is possible to suppress and prevent the developer from slipping in the longitudinal direction of the developing sleeve and to prevent the developer from leaking due to an impact or the like. It is an object of the present invention to provide a developing device, a process cartridge, and an image forming apparatus that can suppress and prevent the developing device.

[0017]

According to a first aspect of the present invention, an object of the present invention is to provide a developing container for accommodating a magnetic developer, a plurality of rotatably supported by the developing container, A developer carrier capable of carrying and transporting the developer in a predetermined direction by arranging a magnet having a magnetic pole, and a predetermined interval at a position opposite to the developer carrier on the developing container side at both ends in the longitudinal direction of the developer carrier. In a developing device having a magnet seal member arranged with the developer opened,
This is achieved by forming a non-magnetic member and a magnetic member, and providing the magnetic member in the vicinity of a magnet seal member disposed at both ends in the longitudinal direction of the developer carrying member.

Further, according to the second aspect of the present invention, the above-mentioned object is to provide a developing container for containing a magnetic developer, a plurality of magnetic poles rotatably or fixedly arranged in the developing container, and having a plurality of magnetic poles therein. A developer carrier capable of carrying and transporting the developer in a predetermined direction by rotatably disposing a magnet having a magnet at a position opposed to the developer carrier on the developing container side at both ends in the longitudinal direction of the developer carrier. In a developing device having a magnet seal member arranged at a predetermined interval,
Forming a developer carrier from a non-magnetic member and a magnetic member;
This is achieved by providing the magnetic member in the vicinity of a magnet seal member disposed at both ends in the longitudinal direction of the developer carrier.

According to the third aspect of the present invention, the above object is attained by disposing the magnetic member of the developer carrier so that its surface is exposed to the front side of the developer carrier. Is done.

According to a fourth aspect of the present invention, the object is to form the non-magnetic member into a substantially cylindrical shape and form the magnetic member into a substantially annular shape so that both ends of the non-magnetic member can be formed. This is achieved by disposing a magnetic member on the outer peripheral surface.

Further, according to the fifth aspect of the present invention, the above object is achieved by a method in which the magnet seal member has NS inner surfaces on its inner peripheral surface.
This is achieved by forming the poles by magnetizing multiple magnetic poles.

Further, according to the sixth aspect of the present invention, the above object is achieved by disposing the magnet seal member closer to the longitudinal end of the developer carrier than the magnetic member.

According to a seventh aspect of the present invention, there is provided a process cartridge which is detachably formed in an image forming apparatus main body and has at least an image carrier and a developing device. Developing device,
This is attained by using any one of the first to sixth inventions.

According to an eighth aspect of the present invention, at least the above object is achieved by providing a developing container accommodating a magnetic developer and a magnet disposed in the developing container and having a plurality of magnetic poles therein. A developer carrying member capable of carrying and transporting the developer in a predetermined direction by being disposed; and a magnet seal disposed at a predetermined interval at a position opposed to the developer carrying member on the image container side at both ends of the developer carrying member. In the image forming apparatus provided with the developing device having the member, any one of the first to sixth inventions is used as the developing device, or the seventh invention is provided in the image forming device. This is achieved by arranging the process cartridges.

That is, according to the first aspect of the present invention, since the magnetic member of the developer carrier formed of the non-magnetic member and the magnetic member is provided near the magnet seal member, Due to the action of the magnetic field between the seal member and the magnetic member, sufficient magnetic brushes with strong binding force of the developer are formed at the longitudinal end portion of the developer carrier, thereby exhibiting good sealing properties, and It is possible to suppress or prevent the developer from leaking out of the developer or the impact of the developer.

Further, according to the second aspect of the present invention, even when the magnet in the developer carrier rotates, the magnetic member of the developer carrier formed of the non-magnetic member and the magnetic member can be replaced by the magnet. Since it is provided in the vicinity of the sealing member, the magnetic brush between the magnet sealing member and the magnetic member causes a sufficient magnetic brush having a strong binding force of the developer at the longitudinal end of the developer carrying member. When formed, good sealing properties are exhibited, and leakage or the like of the developer due to slip-through or impact of the developer is suppressed or prevented.

According to the third aspect of the present invention, by arranging the magnetic member so that the surface of the magnetic member is exposed to the surface side of the developer carrying member, the magnetic brush can be formed with a more sufficient spike. As a result, better sealing properties are exhibited, and leakage of the developer due to slip-through or impact of the developer is suppressed or prevented.

According to the fourth aspect of the present invention, a low-cost developer carrier is provided by disposing substantially annular magnetic members at both ends of a sleeve formed of an existing non-magnetic member. As a result, the magnetic brush is formed with sufficient spikes to exhibit good sealing properties, and the developer is prevented from slipping out or leaking due to an impact.

Further, according to the fifth aspect of the present invention, a magnetic seal member in which the NS pole is magnetized into multiple magnetic poles is formed on the inner peripheral surface of the magnetic seal member, so that a more sufficient magnetic brush spike is formed. As a result, better sealing properties are exhibited, and leakage or the like of the developer due to slip-through or impact of the developer is suppressed or prevented.

According to the sixth aspect of the present invention, the magnet seal member is disposed closer to the longitudinal end of the developer carrier than the magnetic member, so that the length of the magnet in the developer carrier can be reduced. In addition to reducing the size and cost of the device, the magnetic member suppresses and prevents interference of the magnetic field between the magnet in the developer carrier and the magnet seal member, and the magnetic pole of the magnet in the developer carrier is reduced. The degree of freedom of the configuration is increased, and the design of the developing device is facilitated.

Further, according to the seventh aspect of the present invention, since the developing device in the process cartridge is any one of the first to sixth aspects, the developing device in the process cartridge can be developed. The leakage of the developer due to the slipping-through of the developer or the impact is suppressed or prevented, and the process cartridge is small and low-cost.

According to the eighth aspect of the present invention, as the developing device of the image forming apparatus, the developing device of the first to sixth aspects can be used.
Since any one of the developing devices of the invention is used, or the process cartridge of the seventh invention is disposed in the image forming apparatus, the developer in the developing device in the image forming apparatus does not pass through or has an impact. In addition to suppressing and preventing the leakage of the developer, a small-sized and low-cost image forming apparatus can be obtained.

[0033]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) First, a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a schematic configuration diagram showing a main part of an image forming apparatus using a transfer type electrophotographic process of a process cartridge detachable type according to the present embodiment.

A process cartridge 10 detachably installed in an image forming apparatus such as a laser beam printer.
Denotes a photosensitive drum 1 which is a rotating photosensitive drum type electrophotographic photosensitive member as an image bearing member on which an electrostatic latent image is formed.
Are arranged so that they can be driven to rotate clockwise, and around the photosensitive drum 1, four process devices of a charging device 2, a developing device 3, and a cleaning device 6 are collectively disposed in a predetermined position of the cartridge housing 9. It is arranged at a position.

When the process cartridge 10 is mounted in the image forming apparatus main body, the process cartridge 10 and the image forming apparatus main body are mechanically and electrically coupled to each other.
The lower surface of the photosensitive drum 1 of the process cartridge 10 comes into contact with the transfer roller 4 disposed in the image forming apparatus main body in a predetermined manner, and the image forming is enabled. Further, when the process cartridge 10 is installed in the image forming apparatus, the process cartridge insertion / removal guide / holding portion 8 of the image forming apparatus main body comes into contact with a predetermined position of the cartridge housing 9.

In the above-described process cartridge, a charging unit, a developing unit or a cleaning unit, and a photosensitive drum are integrally formed into a cartridge, and this cartridge is detachable from the image forming apparatus main body. However, the present invention is not limited to this, and at least one of the charging unit, the developing unit, and the cleaning unit and the photosensitive drum may be integrally formed as a cartridge so as to be detachable from the image forming apparatus main body. Further, at least the developing unit and the photosensitive drum may be integrally formed as a cartridge so as to be detachable from the image forming apparatus main body.

When the image forming apparatus forms an image using the process cartridge having the above-described configuration, the photosensitive drum 1 is uniformly charged by the charging device 2 and then is moved out of the process cartridge 10 in accordance with the image information signal. The surface of the photosensitive drum 1 is exposed to laser light from the provided image exposing means E to perform image exposure, whereby an electrostatic latent image is formed on the photosensitive drum 1.

The electrostatic latent image formed on the photosensitive drum 1 is
The image is developed by the developing device 3. This visible image is transferred to a transfer unit, which is a transfer unit facing the photosensitive drum 1, located outside the process cartridge 10 at a position facing the photosensitive drum 1. The image is transferred onto the transfer material by the pressing pressure. The transfer material onto which the image has been transferred is conveyed to a fixing device 5 such as a heat fixing method, where the visible image on the transfer material is fixed, and is discharged out of the device as an image formed product (print, copy). ing. Further, the surface of the photosensitive drum after the transfer of the toner image to the transfer material is cleaned by the cleaning device 6 of the process cartridge 10 by removing the adhered contaminants such as residual toner on the photosensitive drum 1 and repeatedly used for image formation. It has become so.

In the above, the peripheral speed of the photosensitive drum 1 is 94
mm / sec, the outer diameter is 30 mm, the peripheral speed of the composite sleeve 31 is 111 mm / sec, and the outer diameter of the composite sleeve 31 is 1 mm.
6 m. The rotation direction of the sleeve 31 was set to the forward direction with respect to the photosensitive drum 1. Photosensitive drum 1 and composite sleeve 31
Was 0.3 mm.

The developing device 3 arranged in the process cartridge 10 will be described with reference to FIGS. FIG. 2 is a schematic configuration diagram showing the vicinity of the middle of the composite sleeve of the developing device, FIG. 3 is a schematic configuration diagram showing the vicinity of the end of the composite sleeve of the developing device, and FIG. FIG. 5 is a perspective explanatory view showing a sealing member, FIG. 5 is a partial sectional explanatory view showing a longitudinal end of the developing device, and FIG. 6 is a perspective explanatory view showing a magnetization pattern of a magnet sealing member. FIG. 7 is a schematic diagram showing the state of the lines of magnetic force between the composite sleeve and the magnet seal member.

The developing device 3 for developing an electrostatic latent image includes a developing container 30 for storing a magnetic toner as a magnetic developer, and an opening provided at a position facing the photosensitive drum 1 of the developing container 30. Composite sleeve 3 which is a cylindrical developer carrier
2 is rotatably disposed in the counterclockwise direction of the arrow in FIGS. 2 and 3, and a regulating blade 33 as a developer layer thickness regulating means is in contact with the surface of the composite sleeve 31.
Further, a magnet seal member 34 for regulating the movement of the toner on the composite sleeve 31 in the longitudinal direction toward the developing container 30 at both ends in the longitudinal direction of the composite sleeve 31.
However, the developing device 3 is configured by being provided in a non-contact manner with the composite sleeve 31 and provided with a stirring device or the like for stirring the toner in the developing container 30.

According to the developing device 3 having the above configuration, the magnetic toner in the developing container 30 is carried on the surface of the non-magnetic member 31a of the composite sleeve 31 by the magnetic force of the magnet roller 32 in the composite sleeve 31. The magnetic toner carried on the non-magnetic member 31 is conveyed in the direction of the regulating blade 33 by the rotation of the composite sleeve 31 and regulated by the regulating blade 33 to a predetermined layer thickness.

The magnetic toner regulated to a predetermined layer thickness by the regulating blade 33 visualizes a latent image formed on the photosensitive drum 1 moving in the clockwise direction indicated by an arrow in FIGS. At this time, a vibration bias voltage in which a DC voltage is superimposed on an AC voltage is applied to the composite sleeve 31 from a power supply. Note that a rectangular wave, a sine wave, or the like can be used as the waveform of the vibration bias voltage.

As shown in FIGS. 4 and 5, the composite sleeve 31 formed in a substantially cylindrical shape includes a substantially cylindrical non-magnetic member 31a made of, for example, aluminum, stainless steel, or the like.
It is formed from two substantially annular magnetic members 31b made of iron, an iron alloy, or the like, and at both longitudinal ends of the nonmagnetic member 31a,
Two annular magnetic members 31b are provided at positions near the magnet seal member 34, and the magnetic members 31b are disposed at both ends of the composite sleeve 31, and the outer peripheral surface of the magnetic member 31b is located on the outer peripheral surface side of the composite sleeve 31. It is arranged to be exposed. The length of the non-magnetic member 31a along the longitudinal direction of the composite sleeve is adjusted so as to be equal to or greater than the longitudinal width of the developing region. Is prevented from entering the coat area.

As shown in FIG. 5, the composite sleeve 31
The outer end is rotatably held by a sleeve bearing 38 provided at a predetermined position of the developing container 30. The regulating blade 33 in contact with the composite sleeve 31 is disposed on the upstream side in the rotation direction of the composite sleeve 31 from the developing area, and is positioned above the composite sleeve 31 by the regulating blade 33 at the opening position of the developing container 30 of the composite sleeve 31. The thickness of the magnetic toner carried on the recording medium is regulated to a predetermined thickness so that the magnetic toner can be transported to the developing area.

In the composite sleeve 31, a magnet roller 32, which is a magnet having a plurality of magnetic poles on its outer peripheral surface, is provided.
Are fixedly arranged so that magnetic toner is carried on the surface of the composite sleeve 31 by the magnetic force of the magnet roller 32, and that the photosensitive drum 1 and the composite sleeve 31 can be conveyed to the developing area where the composite sleeve 31 is opposed by the rotation of the composite sleeve 31. It has become. The length of the magnet roller 32 is a length corresponding to the distance between the two magnetic members 31b at both ends of the composite sleeve 31.

As shown in FIG. 2, the magnet roller 32 has two N poles N1, N2 and two S poles S1,
S2 is provided. The lines of magnetic force generated by the magnetic poles of the magnet roller 32 are combined with the composite sleeve 3 at the non-magnetic member 31a.
1 is formed outward from the surface of the composite sleeve 31 so that the magnetic member 31b is shielded by the magnetic member 31b so that the magnetic member 31b does not protrude from the surface of the composite sleeve 31. The peak value of the magnetic flux density in the direction normal to the sleeve surface on the sleeve surface at each magnetic pole of the magnet roller 32 was set to 400 to 900 × 10 ⁻⁴ T (tesla).

The magnet seal member 34 has, for example, a magnet portion 34a having a substantially arc-shaped cross section along the outer periphery of both ends of the composite sleeve 31, and the magnet member 34a is formed of N1 of the magnet roller 32.
The magnet seal member 34 is disposed at a position facing each of the poles S2, N2, and N2, slightly outside the magnetic member 31b of the composite sleeve 31 with a gap g from the outer peripheral surface of the composite sleeve 31. Can be locked in a predetermined position of the developing container 30. The magnet seal member 3
4, the inner end side along the longitudinal direction of the composite sleeve 31 is
The composite sleeve 31 is provided so as to be arranged at an outer peripheral position on the outer end side of the magnetic member 31b. The gap g between the magnet seal member 34 and the composite sleeve 31 is 0.1 to
It was set to 0.7 mm.

As shown in FIG. 5, the positional relationship between the magnet seal member 34, the magnetic member 31b of the composite sleeve 31, and the magnet roller 32 in the composite sleeve in the present embodiment is determined by the longitudinal end of the magnet roller 32. In position, width 3
The center of the magnetic member 31b formed in mm is arranged, and the outer end of the magnetic member 31b along the longitudinal direction of the composite sleeve 31 and the longitudinal end of the composite sleeve 31 of the magnet seal member 34 The magnet seal member 34 is arranged at an interval g from the outer periphery of the composite sleeve 31 such that the inner end along the direction overlaps.

More specifically, the magnetic member 31 shown in FIG.
The inner end of the magnet roller 32 has a width L1 extending into the longitudinal center of the magnet roller 32 from the longitudinal end thereof, and the outer end of the magnetic member 31b has a width from the longitudinal end of the magnet roller 32. L2, which is the width that protrudes, L3, which is the width where the inner end side of the magnetic seal member 34 overlaps the outer periphery of the magnetic member 31b, and the outer end of the magnet seal member 34 protrudes from the outer end of the magnetic member 31b. The respective values of the width L4 and the width L1 are 1.5 mm and L2 = 1.5 mm, respectively.
Each of the magnet seal member 34, the magnetic member 31b, and the magnet roller 32 is arranged such that L3 = 1.5 mm and L4 = 2.5 mm at 1.5 mm.

As shown in FIG. 6, the magnet seal member 34 is formed by magnetizing NS poles to multiple magnetic poles on the inner peripheral surface of the magnet portion 34a. Specifically, it has four S poles S11, S12, S13, S14 and three N poles N11, N12, N13 on its inner peripheral surface, and SN poles are alternately arranged. The peak value of the magnetic flux density on the sleeve surface at each magnetic pole of the magnet seal member 34 in the direction normal to the sleeve surface is 1000 to 2200 × 1.
0 ^-4 T (tesla).

As shown in FIG. 7, at the surface of the magnetic member 31b of the composite sleeve 31 facing the magnetic pole N (or S) of the magnet seal member 34, the magnetic pole S ( Or N) is induced, and magnetic poles having different polarities are formed at positions facing each other between the magnet seal member 34 and the magnetic member 31b. The formation of the NS forward magnetic field between the opposing magnetic poles forms dense magnetic lines of force between the magnet seal member 34 and the magnetic member 31b, and the magnetic brush spikes along the lines of magnetic force. It is formed. The spikes of the magnetic brush are formed densely in the gap g between the outer peripheral surface of the developer carrying member and the inner peripheral surface of the magnet seal member 34 to fill the gap, thereby exhibiting good sealing performance. The composite sleeve 31 rotates in a predetermined direction. However, since the magnetic member 31b is formed in a substantially annular shape, a magnetic field is formed between the magnet seal member 34 and the magnetic member 31b without interruption.

As described above, since the magnet seal member 34 has a configuration in which the NS pole is magnetized to multiple magnetic poles on the inner peripheral surface thereof, the NS formed by the magnet seal member 34 and the magnetic member 31b is used.
A large number of magnetic fields can be formed, and the magnetic brush ears can be effectively formed in a wide range, so that a good sealing property can be exhibited, and the developer can be effectively prevented from slipping through the developer or from impact. It can be suppressed and prevented.

Further, the magnetic member 31b is
1, the distance between the magnetic member 31b and the magnet seal member 34 is effectively reduced, so that the lines of magnetic force are formed in a concentrated manner, and the binding force of the developer is stronger. Since the brush can be formed, the sealing property can be improved, and the leakage of the developer and the leakage of the developer against the impact can be effectively suppressed or prevented.

Further, in the present embodiment, the magnetic member 31b
Is disposed at a position covering the end portion of the magnet inside the composite sleeve, and the magnet seal member 34 is disposed on the sleeve 31 more than the magnetic member 31b.
Since the magnets inside the composite sleeve can be shortened since they are arranged on the end side in the longitudinal direction of the composite sleeve, the size and cost of the device can be reduced, and the magnet inside the composite sleeve can be reduced by the magnetic member. Therefore, the degree of freedom of the magnetic pole configuration of the magnet inside the composite sleeve is improved, and the design of the developing device is facilitated.

According to the embodiment described above, it is possible to suppress and prevent the developer from slipping in the longitudinal direction of the composite sleeve while being a compact developing device. In addition, good sealing properties can be obtained in which the developer does not leak due to an impact or the like when the user attaches or detaches the process cartridge to or from the image forming apparatus main body. Further, the degree of freedom of the magnetic pole configuration of the composite sleeve internal magnet is improved, and the design of the developing device can be facilitated.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. In this embodiment,
A magnetic member is arranged in a mesh shape or the like at both ends of the composite sleeve so that the magnetic poles of the magnet seal member are concentrated. In this embodiment, the configuration of the magnetic member 31b of the first embodiment is different, but members such as a magnet roller and a magnet seal member have the same configuration as the first embodiment.

FIG. 8 is a partial cross-sectional explanatory view showing an end portion in the longitudinal direction of the developing device when the developing device of the present embodiment is applied to a digital electrophotographic copying machine. It is a perspective explanatory view showing the case where a member is arranged.

As shown in FIG. 8, a magnetic member 40 is disposed at the longitudinal end of the composite sleeve 31. As shown in FIG. 9, the magnetic member 40 is formed by, for example, combining iron, iron alloy, or the like having a small width in a mesh shape. Further, the magnetic member 40 is disposed so that the positional relationship between the magnet roller 32 and the magnet seal member 34 is the same as that of the first embodiment, and the magnetic seal member 34 is disposed on the narrow mesh portion. The magnetic flux lines are concentrated on the narrow mesh part, and the magnetic brush ears can be effectively formed and a better sealing performance can be obtained. Of the developer can be more effectively suppressed and prevented.

As shown in FIG. 10, instead of the mesh shape, magnetic materials such as iron or iron alloy having a small width are arranged at predetermined intervals, and the magnetic materials are connected with a non-magnetic material such as aluminum. The line-shaped magnetic member is combined with the composite sleeve 31.
The same effect can be obtained by providing the two end portions at both ends.

Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIGS. In this embodiment, a composite sleeve is formed by arranging an annular magnetic member on the outer peripheral surface of a longitudinal end portion of a non-magnetic member formed in a substantially cylindrical shape. Although the shape of the composite sleeve is different, other members such as the magnet roller and the magnet seal member have the same configuration as that of the first embodiment.

FIG. 11 is a partially sectional explanatory view showing the longitudinal end of the developing device when the developing device of the present embodiment is applied to a digital electrophotographic copying machine.

As shown in FIG.
Is a non-magnetic sleeve 4 in which a non-magnetic member is formed in a substantially cylindrical shape.
1 and an annular member 42 in which a magnetic member is formed in a substantially annular shape. The annular member 42 is formed on the outer peripheral surfaces of both ends of the non-magnetic sleeve 41 by being locked.
The annular member 42 is disposed so as to protrude from the surface thereof. By configuring the composite sleeve in this manner, a general-purpose non-magnetic sleeve can be used as it is, and a composite sleeve can be formed by arranging an annular member formed of a magnetic member on the surface of the general-purpose non-magnetic sleeve. Therefore, the structure is simple and the manufacturing cost of the sleeve can be reduced as compared with the composite sleeve in which the non-magnetic member and the magnetic member used in each of the above embodiments are integrally formed.

In the present embodiment, similarly to the first embodiment, the lines of magnetic force are formed between the annular member 42 made of a magnetic member and the magnet seal member 34, and the magnetic brush ears are formed. Good sealing properties can be exhibited, and the developer can be effectively suppressed or prevented from leaking out of the developer or leakage of the developer due to impact.

As shown in FIG. 12, an annular member 43 formed by dispersing a magnetic member 43b on a base material 43a made of a non-magnetic material is attached to a substantially cylindrical non-magnetic sleeve 41.
May be locked to the outer peripheral surfaces of both ends of the composite sleeve to form a composite sleeve. In this case, the manufacturing cost of the composite sleeve 31 can be reduced, and the magnetic members 4 dispersed by the magnetic poles of the magnet seal member, as in the second embodiment.
The opposed magnetic poles are induced in the portion 3b, and the lines of magnetic force are concentrated, and the magnetic brush ears can be effectively formed, so that a better sealing property can be exhibited, and the developer leaks due to the slipping-off of the developer and the impact. Etc. can be more effectively suppressed and prevented.

In addition to the composite sleeve of each of the above embodiments,
As shown in FIGS. 13 to 15, the composite sleeve can have various configurations. The configuration is the same as that of the first embodiment except that the configuration of the composite sleeve is different.

Specifically, as shown in FIG. 13, steps are formed at both ends of a substantially cylindrical non-magnetic sleeve 45a, and the non-magnetic sleeve 45a is formed on the inner end side of the substantially annular magnetic member 45b. A joining step to be joined to the step is formed, and two magnetic members 45b are joined to both ends of the non-magnetic sleeve 45a to form the composite sleeve 45. In this case, the magnetic member 45b and the non-magnetic sleeve 45a are both joined to each other in an uneven shape, and the magnetic member and the non-magnetic sleeve are firmly joined.

As shown in FIG. 14, an annular groove is provided on the outer peripheral surface of both ends of the non-magnetic sleeve 46a, and a substantially annular magnetic member 46b is embedded in the groove. You may make it join a member firmly. Further, as shown in FIG. 15, an annular groove is provided on the inner peripheral surface at both ends of the non-magnetic sleeve 47a, and a substantially annular magnetic member 47b is embedded in the groove.
The non-magnetic sleeve and the magnetic member may be firmly joined.

Even in the case of using the composite sleeve in which the magnetic members are arranged as shown in FIGS. 13 to 15, a good sealing property is provided between the magnet seal member 34 and the magnetic members as in the first embodiment. Can be exerted, and the leakage of the developer or the leakage of the developer against impact can be more effectively suppressed and prevented.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described with reference to FIG. In the present embodiment, the magnet roller in the composite sleeve is rotatably arranged. The configuration is the same as that of the first embodiment except that the configuration of the magnet roller inside the composite sleeve is different.

FIG. 16 is a partial cross-sectional explanatory view showing a longitudinal end portion of the developing device when the developing device of the present embodiment is applied to a digital electrophotographic copying machine.

As shown in FIG. 16, the magnet roller 32 'arranged in the composite sleeve 31 has four N poles N on its surface.
1, N2, N3, N4 and four south poles S1, S
2, S3, S4, and arrow a in FIG.
It is provided to rotate in the clockwise direction shown in
The magnetic toner on the composite sleeve 31 rotating counterclockwise in the direction of arrow b in FIG. 16 can be transported in the direction of arrow b while being attached to the surface by the magnetic force of the magnet roller 32 '. Further, the magnet seal members 34 are arranged near the magnetic member 31b at both ends of the developing sleeve 31 with an interval g from the outer peripheral surface thereof, and three S poles S11, S12, S13, and 3 on the inner peripheral surface. N pole N11,
N12 and N13.

In the developing device having the above structure, the magnetic member 31b does not affect the magnetic field of the magnet roller 32 'in the composite sleeve 31 outside the magnetic member 31b. Furthermore, similarly to the first embodiment, the magnetic lines of force are formed densely, and the magnetic brush can be formed by the magnetic lines of force. For this reason, conventionally, it has been difficult to prevent the toner from slipping when the magnet roller in the composite sleeve rotates. However, even when the magnet roller in the composite sleeve rotates, a good seal can be obtained. It is possible to suppress and prevent the developer from slipping in the longitudinal direction of the composite sleeve even though it is a compact developing device, and it is strong when the user attaches or detaches the process cartridge to / from the image forming apparatus. It is possible to obtain a good sealing property in which the developer does not leak even when an impact is applied.

In the developing device of the type in which the magnet roller rotates as in this embodiment, the sleeve may not rotate in some cases. Needless to say, the above effects can be obtained even when the sleeve does not rotate.

In the above embodiments, the case where the magnetic toner is used as the magnetic developer has been described as an example. However, a two-component magnetic developer composed of a non-magnetic toner and a magnetic carrier is used as the developer. The same effect can be obtained. Further, the developing device of each of the above embodiments is provided in the process cartridge. However, the present invention is not limited to this, and the developing device of each of the above configurations can be arranged in the image forming apparatus.

[0078]

As described above, according to the first aspect of the present invention, since the magnetic member of the developer carrier is provided near the magnet seal member, the magnet seal member and the magnetic member are provided. With the action of the magnetic field, a sufficient brushing force of the magnetic brush with a strong binding force of the developer can be formed at the longitudinal end of the developer carrying member, and a good sealing property can be exhibited. It is possible to suppress and prevent leakage of the developer due to slip-through or impact.

Further, according to the second aspect of the present invention, even when the magnet in the developer carrier rotates, the magnetic field between the magnet seal member and the magnetic member acts in the longitudinal direction of the developer carrier. It is possible to form sufficient magnetic brush ears with strong binding force of the developer at the end portion, exhibit good sealing performance, and suppress / prevent leakage of the developer and leakage of the developer due to impact. be able to.

Further, according to the third aspect of the present invention, since the surface of the magnetic member is arranged so as to be exposed on the surface side of the developer carrying member, the space between the magnetic member and the magnet seal member can be reduced. Sufficient spikes of the magnetic brush are formed, and a better sealing property is exhibited, so that the developer can be prevented from slipping through the developer or leaking due to impact.

According to the fourth aspect of the present invention, a low-cost developer carrier can be provided by disposing substantially annular magnetic members at both ends of a sleeve formed of an existing non-magnetic member. Good sealing properties can be exhibited by the body, and leakage or the like of the developer due to slip-through or impact of the developer can be suppressed or prevented.

Further, according to the fifth aspect of the present invention, by forming a magnet seal member in which the NS pole is magnetized to multiple magnetic poles on the inner peripheral surface, a more sufficient spike of the magnetic brush is formed. In addition, it is possible to exhibit better sealing properties and to suppress / prevent leakage of the developer or leakage of the developer due to impact.

According to the sixth aspect of the present invention, the length of the magnet in the developer carrier can be reduced by disposing the magnet seal member on the longitudinal end side of the developer carrier with respect to the magnetic member. In addition to reducing the size and cost of the apparatus, the magnetic member can suppress and prevent the interference of the magnetic field between the magnet in the developer carrier and the magnet seal member. This increases the degree of freedom in the configuration of the magnetic poles, and provides a developing device that is easy to design.

According to the seventh aspect of the present invention, since the developing device in the process cartridge is any one of the first to sixth aspects, the developer can pass through. A process cartridge can be obtained in which the leakage of the developer due to shock or impact is suppressed or prevented, and the developer leaks even when a shock is applied by the user when the process cartridge is attached to or detached from the image forming apparatus main body. A process cartridge having a good sealing property without any problem is obtained.

Further, according to the eighth aspect of the present invention, as the developing device of the image forming apparatus, the first to sixth aspects can be used.
Since any one of the developing devices of the invention is used, or the process cartridge of the seventh invention is disposed in the image forming apparatus, the leakage of the developer due to the slip-through of the developer or the impact is suppressed. Thus, it is possible to obtain an image forming apparatus capable of performing easy maintenance and good image formation.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a main part of an image forming apparatus of a first embodiment of a process cartridge detachable type.

FIG. 2 is a schematic configuration diagram showing the vicinity of the middle of a composite sleeve of the developing device.

FIG. 3 is a schematic configuration diagram showing the vicinity of an end of a composite sleeve of the developing device.

FIG. 4 is an explanatory perspective view of a composite sleeve and a magnet sealing member.

FIG. 5 is a partially sectional explanatory view showing a longitudinal end of the developing device.

FIG. 6 is an explanatory perspective view showing a magnetization pattern of a magnet seal member.

FIG. 7 is a schematic diagram showing a state of lines of magnetic force between a composite sleeve and a magnet sealing member.

FIG. 8 is a partially sectional explanatory view showing a longitudinal end portion of a developing device according to a second embodiment.

FIG. 9 is an explanatory perspective view showing a case where magnetic members are arranged in a mesh shape.

FIG. 10 is a perspective explanatory view showing a case where magnetic members are arranged in a line.

FIG. 11 is an explanatory partial cross-sectional view illustrating a longitudinal end portion of a developing device according to a third embodiment.

FIG. 12 is a perspective explanatory view showing a case where magnetic members are dispersed and arranged.

FIG. 13 is a partial cross-sectional explanatory view showing an end in a longitudinal direction of the developing device when an inner end of a magnetic member is fitted to a front end of a non-magnetic member.

FIG. 14 is a partial cross-sectional explanatory view showing a longitudinal end of the developing device when a magnetic member is embedded in a groove on the outer peripheral surface of a non-magnetic member.

FIG. 15 is a partial cross-sectional explanatory view showing a longitudinal end of the developing device when a magnetic member is embedded in a groove on the inner peripheral surface of a non-magnetic member.

FIG. 16 is an explanatory partial cross-sectional view illustrating a longitudinal end portion of a developing device according to a fourth embodiment.

FIG. 17 is a schematic configuration diagram showing a main part of a developing device built in a conventional process cartridge.

FIG. 18 is a partial cross-sectional explanatory view showing the vicinity of an end in a longitudinal direction of a conventional developing device.

FIG. 19 is a schematic configuration diagram showing a developing device using a conventional magnet seal member.

[Explanation of symbols]

 Reference Signs List 1 photosensitive drum (image carrier) 3 developing device 10 process cartridge 30 developing container 31 composite sleeve (developer carrier) 31a non-magnetic member 31b magnetic member 32 magnet roller (magnet in developer carrier) 34 magnet seal member

Claims (8)

[Claims] 1. A developing container which stores a magnetic developer and a magnet rotatably supported by the developing container and having a plurality of magnetic poles inside the developing container so that the developer can be carried and transported in a predetermined direction. A developing device comprising: a developer carrier; and a magnet seal member disposed at a predetermined interval at a position opposed to the developer carrier on the developing container side at both ends in the longitudinal direction of the developer carrier. Is formed from a non-magnetic member and a magnetic member, and the magnetic member is provided in the vicinity of a magnet seal member disposed at both ends in the longitudinal direction of the developer carrier. 2. A developer container containing a magnetic developer, and a developer rotatably or fixedly disposed in the developer container and a magnet having a plurality of magnetic poles rotatably disposed inside the developer container, thereby allowing the developer to be fixed to a predetermined amount. Developing device having a developer carrier capable of carrying and transporting in the direction, and a magnet seal member disposed at a predetermined interval at a position facing the developer carrier on the developing container side at both ends in the longitudinal direction of the developer carrier. In the, the developer carrier is formed from a non-magnetic member and a magnetic member,
The developing device, wherein the magnetic member is provided in the vicinity of a magnet seal member disposed at both longitudinal ends of the developer carrier. 3. The developing device according to claim 1, wherein the magnetic member of the developer carrying member is arranged such that a surface thereof is exposed to a surface side of the developer carrying member. 4. The non-magnetic member is formed in a substantially cylindrical shape, the magnetic member is formed in a substantially annular shape, and the magnetic members are disposed on outer peripheral surfaces at both ends of the non-magnetic member. The developing device according to any one of claims 1 to 3. 5. The developing device according to claim 1, wherein the magnet seal member has an NS pole formed on an inner peripheral surface thereof by being magnetized into multiple magnetic poles. . 6. The developing device according to claim 1, wherein the magnet seal member is disposed closer to a longitudinal end of the developer carrier than the magnetic member. . 7. A process cartridge which is detachably formed in an image forming apparatus main body and has at least an image carrier and a developing device, wherein the developing device is any one of claims 1 to 6. A process cartridge, which is the developing device according to any one of claims 1 to 3. 8. A developer capable of carrying and transporting a developer in a predetermined direction by arranging at least a developer container containing a magnetic developer and a magnet arranged in the developer container and having a plurality of magnetic poles therein. In an image forming apparatus provided with a developing device having a carrier and magnet seal members disposed at predetermined positions at opposite ends of the developer carrier opposite to the developer carrier on the image container side, an image forming apparatus includes: A developing device according to any one of claims 1 to 6 is used as an apparatus, or a process cartridge according to claim 7 is arranged in an image forming apparatus. Image forming apparatus.