JPH0683180A - Developing device and process cartridge - Google Patents

Abstract

PURPOSE:To suppress the generation of a defect in an image such as nonuniformity of density and the abrasion of a magnetic roller without sliding a developing sleeve and the magnetic roller and to attain reuse by fixing/holding both end shaft parts of the magnetic roller on a holder without allowing them to be in contact with a sleeve flange and the developing sleeve. CONSTITUTION:The magnetic roller 19 is supported by the outside in the axial direction of a developer carrier 12 in the non-contact states of both ends 19a and 19b with the inwalls of flanges 15 and 17. In other words, the magnetic roller 19 included in the developing sleeve 12 has a big central part 19c, plural magnetic poles and both slender end parts 19a and 19b. Both end parts 19a and 19b are protruded from the sleeve flanges 15 and 17 and held by the holders 21a and 21b. Thus, the magnetic roller 19 is floated/held with respect to the developing sleeve 12, so that a vibration accompanying with the rotation of the developing sleeve 12 and positional relation with a photosensitive drum are not changed by shrinks and a deflection, but the generation of the defect in the image can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device and a process cartridge used in an image forming apparatus such as a laser beam printer and a copying machine.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, a developing device used in an image forming apparatus is provided with a non-magnetic hollow cylindrical developing sleeve, a bearing for supporting the developing sleeve, and an inside of the developing sleeve. Has a magnet. Figure 4
Reference numeral 19 denotes a magnet roller, 12 a developing sleeve, 15 and 17 a sleeve flange adhesively fixed to the developing sleeve, 22 bearings press-fitted to the sleeve flange, and 18 rotatably receiving the sleeve flange. A bearing 12a is a sleeve gear for receiving rotational drive from a photosensitive drum (not shown) and transmitting it to the developing sleeve. A reference numeral 21 is a holder for holding the developing sleeve in a frame (not shown) via the bearing 18. is there.

Here, the developing sleeve 12 and the sleeve flanges 15 and 17 are both made of non-magnetic aluminum and are made by cutting, and are extremely highly accurate parts. The bearings 18 and 22 are expensive ball bearings in order to rotate the developing sleeve with high precision.

As described above, in the conventional developing device, the magnet roller 19 is contained in the developing sleeve 12, and the gear side is supported by the sleeve flange 17 through the bearing 22.
The opposite side is fixedly supported by the holder 21 so as not to rotate. Further, the developing sleeve 12 has sleeve flanges 15 and 17 at both ends, and a holder 18 is provided by bearings 18.
It is rotatably held at 1. Also, the developing sleeve 1
A developing bias is applied to the image forming apparatus 2 via the bearings 18 and 22 from the image forming apparatus main body.

Next, a conventional example will be described in which an image forming apparatus such as a copying machine or a laser beam printer has a process cartridge removably disposed in the main body of the apparatus to facilitate maintenance of the apparatus. In such a process cartridge, a developing roller is provided in a developing device for developing an electrostatic latent image formed on a photosensitive drum, which is an image carrier, via a developer (toner).
The toner in the developing device is supplied toward the photosensitive drum by the action of the magnetic force of the developing roller.

Such a developing roller is, as shown in FIG.
It is composed of a cylindrical developing sleeve 100 which rotates in a fixed direction and a magnet roller 101 which is disposed in the developing sleeve 100 and has a plurality of magnetic poles N1, N2, S1 and S2 as shown in FIG. Magnet roller 10
The other end 101a of the core metal portion 1 has a shape obtained by cutting a part of the core metal cylindrical portion as shown in FIG. 9, and a plurality of magnetic poles are determined for the developing device 110 by using the cut flat surface portion. Set to the closed position. And this core metal part 101
a is a holder 111a fixed to the developing device main body 110
Fixed to. Also, the other end 101b of the magnet roller
Is a holder 111b fixed to the developing device main body 110.
Fixed to. The developing sleeve 100 is arranged so as to cover the magnet roller 101 with a slight clearance from the magnet portion 101c of the magnet roller 101, and both ends of the developing sleeve 100 are provided with bearing members 102 and 102, and the developing device main body 11 is provided.
It is pivoted to 0. In this configuration, when the magnet roller 101 is received in the thrust direction, the end surfaces of the magnet roller core metal parts 101a and 101b are the holders 111a,
It is received by hitting 111b.

Next, a process cartridge of a type different from the above conventional example will be described. As shown in FIGS. 14 and 15, the process cartridge includes a developing chamber 303.
A pipe-shaped developing sleeve 301 is rotatably disposed in the developing sleeve 301, and a magnet roller 304 including a magnet having a plurality of magnetic poles is housed inside the developing sleeve 301. 302
Are in contact with each other, and the developing blade 302 is connected to the developing container 3
It is attached to 05. Then, the developing sleeve 30
Reference numeral 1 denotes a spacer roller 307 which is a gap holding member so as to have a constant gap with the photosensitive drum 306 which is an image carrier.
The photosensitive drum 306 is urged by the urging means (not shown) via a and 307b.

Toner, which is a developer, is supplied to the developing chamber 303 from an inlet opening 308 of the developing chamber 303 by a conveying means (not shown) from a toner container (not shown) or by dropping. Then, the toner in the developing chamber 303 is attracted to the N1 pole, which is one of the magnetic poles of the magnet roller 304, is agitated by the rotating developing sleeve 301, and is gradually charged.
01 is conveyed in the direction of the arrow in FIG. 14 and enters between the developing blade 302 and the developing blade 30.
2 is strongly pressed against the developing sleeve 301 to be charged, and the amount of the charge is increased at a stroke.
With the rotation of 01, the toner is conveyed to the outside of the developing chamber 303. The developing blade 302 charges the toner, increases the amount of the charge, and at the same time regulates the thickness of the toner layer on the developing sleeve 301.

By the way, most of the developing sleeve 301 is made of a conductor such as aluminum alloy, and as shown in FIG. 15, a bias plate 309 is incorporated into the inner diameter of the developing sleeve pipe at one end thereof, as shown in FIG.
A developing bias is applied to the developing bias feeding unit (not shown) of the main body of the image forming apparatus.

Therefore, the toner conveyed from the developing chamber 303 by the developing sleeve 301 is blown onto the electrostatic latent image on the photosensitive drum 306 by the developing bias, and the electrostatic latent image is developed by this toner. The toner that has not been used for development is returned to the developing chamber 303 as the developing sleeve 301 rotates.

At one end of the developing sleeve 301, a flange 313 is fitted and joined to the inner diameter of the pipe of the developing sleeve 301, and the flange 313 is supported by a bearing 311a. On the other hand, the developing sleeve 301
The other end of the spacer roller 30 is
7b is fitted and attached to the outer diameter, and the outer diameter of the spacer roller 307b is supported by the bearing 311b.

The bias plate 309 is shown in FIGS.
As shown in FIG.
Development sleeve 3 via 309b, 309c and 309d
It is fixed by coming into contact with the inner peripheral wall of 01 and is electrically connected to the developing sleeve 301. Arms 309e and 309f are formed on the bias plate 309, and these arm portions 309e and 309f are in contact with the electrode plate 314 attached inside the developing container 305 of the process cartridge. The electrode plate 314 contacts a developing bias contact portion (not shown) of the image forming apparatus main body when the process cartridge is incorporated in the image forming apparatus main body and fixed at a predetermined position, and is connected to the developing bias power supply device (not shown). Power is supplied from (not shown).

The magnet roller 304 has its end shaft portion extended and is fixedly supported by the developing container 305. The sleeve gear 312 that rotates the developing sleeve 301 in a fixed direction is driven by a drum gear 316 that is coupled to the photosensitive drum 306 by adhesion or press fitting, and rotates in a fixed direction. These gears are helical gears that can ensure a sufficient meshing ratio in order to sufficiently transmit the driving force.

Further, by adopting a helical gear,
The developing sleeve 301 can be pressed in one direction by utilizing the thrust force when the helical gear rotates due to the nature of the helical gear. This pressed position is used as a reference position for designing the developing sleeve 301.

Explaining with reference to FIG. 15, the teeth of the sleeve gear 312 are twisted in the left direction, the teeth of the drum gear 316 are twisted in the right direction, and the drum gear rotates in the direction of arrow a. The sleeve gear 312 that has received this rotation receives the thrust force generated due to the nature of the helical gear in the direction of arrow b,
The sleeve gear 312 and the flange 313 are the developing container 305.
Move to the surface and touch. This movement amount is a tolerance of a single item or a gap required for assembly, and cannot be set to zero by any means. Further, this position where the developing sleeve 305 has moved to and comes into contact with the surface of the developing container 305 is designed as a design reference position of the developing sleeve 301. Further, the bias plate 309 determines the contact pressure when it comes into contact with the electrode plate 314 so that power can be supplied at this reference position.

[0016]

However, the above-mentioned conventional example has the following problems. Figure 4
According to the conventional apparatus shown in FIG. 1, since the aluminum-cutting sleeve flange and the expensive ball bearing, which require a large number of processing steps, are used, there is a problem that the cost is increased. Therefore, the sleeve flange is press-fitted and fixed to a developing sleeve as a plastic material, and one end of the magnet roller on the gear side is slid on the inner peripheral surface of the sleeve flange, and a ball bearing for rotatably supporting the sleeve flange is made of polyacetal or the like. A device composed of the slidable plastic material has been proposed.

However, in such a developing device,
There were the following problems. If the sleeve flange is formed of a plastic material, a fine uneven shape can be formed on the inner peripheral surface for receiving the magnet roller due to sink marks due to molding shrinkage. Therefore, as the developing sleeve rotates, the magnet roller moves or vibrates depending on the shape of the sink mark, resulting in an image defect. When the magnet roller material is made of plastic material such as nylon, sliding and rubbing against the inner surface of the sleeve flange causes wear and abrasion of the shaft, resulting in large backlash between the inner surface of the flange and image failure due to vibration. Occurs. The magnet roller cannot be reused because the dimensions of the magnet roller change due to use due to wear and abrasion of the shaft portion of the magnet roller.

Further, in the conventional device shown in FIG. 9,
With the recent demand for downsizing of image forming apparatuses, downsizing of the developing device structure has been required. Above all,
There are severe restrictions on the space in the lateral direction, and there is a demand for compactness in units of several mm. The lateral space of the developing device is determined by the length of the magnet roller and the holders at both ends for holding and fixing the magnet roller. When the thrust of the magnet roller is received by the end surface of the magnet roller core bar and the holder, there is a problem that there is only space saving design such as shortening the core bar or thinning the holder plate. was there.

Further, according to the conventional example shown in FIGS. 14 to 17, the bias plate 309 has the arm portions 309e and 309.
f is in contact with the electrode plate 314 with an appropriate deflection,
Has proper contact pressure. As shown in FIG. 15, the developing sleeve 301 rotated by a helical gear in a fixed direction is
It moves in the direction of arrow b by the thrust force. The bias plate 309 must be designed so that an optimum contact pressure can be obtained at the position after this movement. However, power supply failure may occur due to the thrust force acting so that the bias plate 309 and the electrode plate 314 are separated from each other, or the vibration of the image forming apparatus. Therefore, in designing the bias plate 309, it is necessary to take these into consideration, and to design the bias plate 309 so as to be considerably safe so that power supply failure does not occur even when stacking tolerances of many components. The inspection and management required a lot of cost.

Further, for example, when the cartridge is in the physical distribution, when a force acts in the opposite direction to which the thrust force acts, the spring pressure is weakened or deformed, so that a prescribed contact pressure cannot be obtained. .

A first object of the present invention is to solve the above problems and to reuse a magnet roller without causing image defects due to molding shrinkage, abrasion and abrasion even when a plastic material or the like is used for a bearing or the like. It is an object of the present invention to provide a developing device and a process cartridge that can achieve cost reduction.

A second object of the present invention is to provide a developing device and a process cartridge which can solve the above problems and make the lateral length of the developing device compact.

A third object of the present invention is to solve the above problems and to provide a developing device and a process cartridge which do not cause power supply failure when a thrust force acts on the developing sleeve.

[0024]

According to the first invention of the present application,
The first object is a developing device including a developer carrying member having a hollow cylindrical end portion with flanges, and a magnet roller contained in the developer carrying member. This is achieved by being supported on the outer side in the axial direction of the developer carrier without contacting the inner wall of the flange.

According to the second invention of the present application, the second object is to provide a hollow cylindrical developer carrying member and a magnet roller which is contained in the developer carrying member and is axially supported by thrust stopping means. In the developing device, the magnet roller is provided with step portions on shaft portions at both ends, and the magnet roller is pivotally supported so that a surface of the step portion serves as a thrust receiving surface that comes into contact with the thrust stopper. Achieved by

Further, according to the third invention of the present application, the third object is to provide a developer carrying member which rotates in a fixed direction, and the developer carrying member provided at one end of the developer carrying member. In a developing device having a bias electrode disposed so as to come into contact with an electrode plate adjacent to the bias electrode, the bias electrode is provided at an end portion of the developer carrying member in a direction in which a thrust force is applied to the developer carrying member. Developing device characterized by

[0027]

According to the first aspect of the present invention, when the driving force is transmitted to the developer carrying member, the developer carrying member starts to rotate together with the flange. However, the magnet roller provided in the developer carrying member is Since it is not in contact with the flange and is supported on the outer side in the axial direction of the developer carrier, vibrations and the like due to rotation are not transmitted to the magnet roller, and the distance between the latent image carrier and the magnet roller is kept at a predetermined value. To prevent image defects such as uneven density.

Further, according to the second invention of the present application, the magnet roller in the developer carrying member is rotatably supported so that the surfaces of the step portions provided on the shaft portions at both ends serve as thrust receiving surfaces for contacting the thrust stopping means. Has been done. Therefore, for example, by making the axial length of the step portion approximately the same as that of the thrust stop means, it is possible to make the thrust stop means compact by the thickness of the thrust stop means.

Further, according to the third invention of the present application, when the developer carrying member is rotated in a predetermined direction, a thrust force is generated in the developer carrying member in a predetermined axial direction. However, since the bias electrode is provided at the end portion of the developer carrying member on the side where the thrust force is applied, it receives a force in the direction of contacting the electrode plate,
Prevents poor continuity.

[0030]

Embodiments 1 to 6 of the present invention will be described with reference to the drawings.

<First Embodiment> First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a cross section of a process cartridge 6. In FIG. 1, reference numeral 1 denotes a photosensitive drum that is an image carrier that rotates in the direction of the arrow.
Process devices such as a charging device 2, a developing device 3, and a cleaning device 4 are provided around the device. Then, these devices are integrated into the cartridge container 6a,
By disposing the process cartridge 6 in the main body of the image forming apparatus in a detachable manner, for example, when the photosensitive drum 1 reaches the end of its life or the toner (developer) in the developing device 3 is used up. By replacing the entire process cartridge 6, maintenance is facilitated.

The developing device 3 has a developing section 10 having a developing sleeve 12 serving as a developer carrying member facing the photosensitive drum 1 side, and a toner T held therein and supplying the toner T to the developing section 10. Although it is composed of a storage section 11, a lid member 13 having an opening 13 a is sandwiched and held between the developing section 10 and the developer storage section 11. Then, a sealing device 20 described later is attached to the opening 13a of the lid member 13, and the toner T in the developer accommodating portion 11 moves to the developing portion 10 when not in use, and the toner T is discharged to the outside of the process cartridge 6. In addition to preventing T from flowing out, when the process cartridge 6 is mounted in the main body of the image forming apparatus for use, the sealing device 20 is used.
The toner in the developer accommodating portion 11 can be supplied to the developing portion 10 by operating the to open the opening 13a.

The cleaning device 4 rubs the photosensitive drum 1 to remove the residual toner on the photosensitive drum 1, and a waste toner storage portion 4b for storing the waste toner removed by the cleaning blade 4a. The residual toner on the photosensitive drum 1 is cleaned to prepare the photosensitive drum 1 for the next image forming apparatus.

Reference numeral 5 is a shutter for protecting the photosensitive drum 1, and when the process cartridge 6 is mounted in the main body of the image forming apparatus, this shutter 5 is located on one side of the photosensitive drum 1 (of the cleaning device 4). It is designed to evacuate to the lower side.

In the apparatus of this embodiment as described above, when the photosensitive drum 1 uniformly charged by the charger 2 is exposed to the image light L from the scanning optical system (not shown), the photosensitive drum 1 is exposed. Forms an electrostatic latent image. The electrostatic latent image is directed toward the developing device 3 as the photosensitive drum 1 rotates, and the developing sleeve 12 of the developing device 3 supplies the toner T to visualize the electrostatic latent image. Then, this toner image is transferred onto a transfer material via transfer means (not shown),
After the transfer, the photosensitive drum 1 is cleaned of residual toner by the cleaning device 4, and is prepared for the next image formation.

The transfer material is a paper feed cassette (not shown).
The toner image is transferred from the inside to the photosensitive drum 1, and after the toner image is transferred from the photosensitive drum 1, the toner image is transferred to a fixing device (not shown), and the toner image is fixed by the fixing device. It

Next, the developing device 3 according to the present invention will be described in more detail with reference to FIG.

In FIG. 2, reference numeral 15 denotes a sleeve flange, which is inserted and fixed to the developing sleeve 12 by means of press fitting, adhesion, caulking or the like. With the sleeve flange 15 inserted and fixed in the developing sleeve 12, the developing sleeve 1
2 has a boss portion projecting outwardly, and the bearing 18b is engaged with the boss portion. On the other hand, a sleeve flange 17 is also inserted and fixed to the opposite side (right side in the drawing) of the developing sleeve 12 by means of press fitting, bonding, crimping or the like, and a bearing 18a is engaged with the boss portion thereof, and a sleeve gear 12
Is assembled in a state where rotation is stopped by means such as a key and a set screw. Therefore, the developing sleeve 1
Drive 2 is transmitted from the drum gear 1a assembled to the photosensitive drum 1 to the sleeve gear 12a and is rotated in a predetermined rotational speed direction.

Further, as shown in FIG. 3, a bias electrode 16 is incorporated in the sleeve flange 15. The bias electrode 16 is made of a piano wire, a stainless steel wire for spring, a phosphor bronze wire or the like, and one end 16a thereof is wound in a coil spring shape. Therefore, the bias electrode 16 has a spring property and contacts the electrode plate 14 with a predetermined force to establish electrical conduction. The other end 16b of the bias electrode 16 projects from the outer diameter of the sleeve flange 15, and the sleeve flange 15 is press-fitted into the developing sleeve 12 to establish electrical connection with the inner circumference of the developing sleeve 12. That is, by mounting this cartridge on the main body of the image forming apparatus, the electrode plate 14 is connected from the developing bias power supply section (not shown) through the contact point (not shown).
The developing bias is transmitted to the developing sleeve 12, and the developing bias of the developing sleeve 12 is supplied via the bias electrode 16.

On the other hand, the magnet roller 19 contained in the developing sleeve 12 has a thick central portion 19c and a plurality of magnetic poles, and both end portions 19a and 19b are thin.
The both ends 19a, 19b are the sleeve flanges 15,
It projects from 17 and is held by holders 21a and 21b. Further, the shaft portion 19a of the magnet roller 19 has a rectangular cross-sectional shape, which prevents the shaft portion 19a from rotating with respect to the holder 21a and keeps the plurality of magnetic poles at predetermined positions with respect to the photosensitive drum 1. Positioning is fixed. The holders 21a and 21b are connected to the developing container 2
It is positioned at 0 and is fixed by screws.

As a result, since the magnet roller 19 is held in a state of floating in the air with respect to the developing sleeve 12, even when the sleeve flange is formed of a plastic member, the developing roller is rotated due to sink marks and runout. Since the vibration and the positional relationship (distance) with the photosensitive drum do not change, it is possible to suppress the occurrence of image defects such as density unevenness.

<Second Embodiment> First, a second embodiment of the present invention will be described with reference to FIGS. In the following description, the same parts as those in the first embodiment are designated by the same reference numerals. FIG. 5 shows a cross section of the process cartridge 6. In FIG. 5, reference numeral 1 denotes a photosensitive drum that is an image carrier that rotates in the direction of the arrow. Around the photosensitive drum 1, a charging device 2, a developing device 3, and a cleaning device 4 are provided. Such process equipment is provided. Then, these devices are cartridge containers 6
By being fixedly incorporated in a and being detachably provided as the process cartridge 6 in the main body of the image forming apparatus, for example, the photosensitive drum 1 has reached the end of its life or toner (developer) in the developing device 3 has been reached. When the printer is used up, the entire process cartridge 6 is replaced to facilitate maintenance.

The developing device 3 includes a developing section 10 having a developing sleeve 100 which faces the photosensitive drum 1 and serves as a developer carrying member.
The toner storage unit 11 has a toner T inside and supplies the toner T to the developing unit 10.
An opening 13a is provided between the developing section 10 and the developer accommodating section 11.
A lid member 13 having a is sandwiched and held. Then, a sealing device 20 described later is attached to the opening 13a of the lid member 13, and the toner T in the developer accommodating portion 11 moves to the developing portion 10 when not in use, and the toner T is discharged to the outside of the process cartridge 6. In addition to preventing the T from flowing out, when the process cartridge 6 is mounted and used in the main body of the image forming apparatus, the sealing device 2 is used.
By operating 0 to open the opening 13a, the toner in the developer accommodating portion 11 can be supplied to the developing portion 10.

The cleaning device 4 rubs the photosensitive drum 1 to remove the residual toner on the photosensitive drum 1, and a waste toner storage portion 4b for storing the waste toner removed by the cleaning blade 4a. It is configured to clean the residual toner on the photosensitive drum 1 and prepare the photosensitive drum 1 for the next image forming apparatus.

Reference numeral 5 is a shutter for protecting the photosensitive drum 1. When the process cartridge 6 is mounted in the main body of the image forming apparatus, the shutter 5 is located on one side of the photosensitive drum 1 (of the cleaning device 4). It is designed to evacuate to the lower side.

In the apparatus of this embodiment as described above, when the photosensitive drum 1 uniformly charged by the charger 2 is exposed to the image light L from the scanning optical system (not shown), the photosensitive drum 1 is exposed. An electrostatic latent image is formed. The electrostatic latent image is directed toward the developing device 3 as the photosensitive drum 1 rotates, and toner T is supplied by the developing sleeve 100 of the developing device 3 to be visualized as a toner image. Then, this toner image is transferred onto a transfer material through a transfer means (not shown), and the photosensitive drum 1 after transfer is cleaned of residual toner by a cleaning device 4 to prepare for the next image formation. To be

The transfer material is a paper feed cassette (not shown).
The toner image is transferred from the inside to the photosensitive drum 1, and after the toner image is transferred from the photosensitive drum 1, the toner image is transferred to a fixing device (not shown), and the toner image is fixed by the fixing device. It

Next, the developing roller of this embodiment will be described in detail with reference to FIG. As shown in FIG. 6, the developing roller is
A cylindrical developing sleeve 100 rotating in one direction and a magnet roller 101 arranged in the developing sleeve 100.
It consists of and. In the magnet roller 101, the end portions of the core metal parts 101a and 101b are the developing device main body 110.
Fixed to holders 111a and 111b which are fixed to
The developing sleeve 100 has a slight gap with the magnet 101c of the magnet roller 101 so that the magnet roller 1
01 so as to cover the flange member 10 at both ends.
4, 104 is press-fitted or mounted to the bearing member 102,
The developing device main body 110 is pivotally supported via 102.
A gear 103 is provided on one of the bearing members, and the developing sleeve rotates in one direction via a drive gear (shown in the figure).

The magnet roller 101 has a plurality of magnetic forces, and in order to set this magnetic force at an appropriate position, a part of the cylinder of the magnet roller core metal part 101a is cut at an appropriate position and rotated as shown in FIG. It has a flat surface that also serves as a stop.

Further, one of the thrust-direction receiving surfaces of the magnet roller 101 itself is the magnet roller core metal portion 1.
01a is a step surface for magnetic force positioning, and the other is received by a step surface in which the diameter of the magnet roller core metal part 101b is reduced by several mm.

The holders 111a and 111b, which play a role of stopping the thrust of the magnet roller 101, are perforated as shown in the arrow L view and the arrow R view, respectively.
On the inner surface of a, 111b, the magnet roller 101a,
It receives the surface of the step provided on 101b and limits the thrust direction. With this thrust receiving structure, the dimensions of the holders 111a and 111b in the longitudinal direction are
At least the thickness can be reduced, and the longitudinal dimension can be accommodated in a compact size.

<Third Embodiment> Next, a third embodiment of the present invention will be described with reference to FIG. The same parts as those of the second embodiment are designated by the same reference numerals and the description thereof will be omitted.

FIG. 8 shows an embodiment in which the stepped shape provided to bring the magnetic force of the magnet roller 101 to an appropriate position is a common shape of the magnet roller core metal parts 101a and 101b. The advantage that both ends have the same shape is exhibited when the present embodiment is assembled by an automatic machine such as a robot. As the assembling order of this embodiment, the holder 111a is assembled to the developing device main body 110. Next, the developing sleeve 100 in which the gear 103 is engaged is inserted so as to fit into the positioning hole of the magnet roller 101 of the holder 111a. At this time, the magnet roller 1
If both ends of the magnet roller 101 are made to have the same shape so that the insertion hole of No. 01 and the magnet roller fit well, the insertion will be easy if the automatic machine senses the opposite side to insert the hole at the time of insertion. There is a merit that you can do it.

<Fourth Embodiment> Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 11 is a vertical cross-sectional view of a developing unit of a cartridge that is attachable to and detachable from the image forming apparatus according to the present invention. In FIG. 11, 201 is a cylindrical developing sleeve that rotates in a fixed direction, and a magnet roller 204 is disposed inside the developing sleeve 201. Both ends of the cored bar portion 204a of the magnet roller 204 are connected to the developing device main body 20.
5, the developing sleeve 201 is fixed to the holder 215, and the developing sleeve 201 is fixed to the magnet portion 20 of the magnet roller 204.
The magnet roller 204 is arranged so as to cover the magnet roller 204 with a slight gap from the magnet 4b. A flange 213, together with a bias plate 209, is fixed to one side of the developing sleeve 201 by press fitting or adhesion, and is pivotally supported by the developing device main body 205 via a bearing member 211a.

The other side of the developing sleeve 201 is in contact with a photosensitive drum (not shown), and a roller 207 for keeping the distance between the photosensitive drum and the developing sleeve 201 constant is inserted.
It is pivotally supported by the developing device main body 205 via a bearing member 211b. A sleeve gear 212 made of a helical gear is engaged with the flange member 213, and the sleeve gear 212 is driven by a drum gear of the helical gear which is press-fitted or adhered to a photosensitive drum (not shown) to obtain a predetermined force. It rotates in a fixed direction at the number of rotations. The bias plate 209 is inserted into the developing sleeve 201 together with the flange 213, and the bias plate 209 is made of phosphor bronze, a stainless steel plate for spring, or the like. Inside the developing sleeve 201, the bias plate 209 comes into contact with the developing sleeve 201 with a spring force and is electrically connected to the developing sleeve 201. There is continuity. Further, the bias plate 209 is inserted up to the flange portion of the flange 213, set at a predetermined position, and the bearing member 21
Electrode plate 2 provided between 1a and developing device main body 205
I am in contact with 14. That is, by mounting this cartridge on the main body of the image forming apparatus, a developing bias (not shown) is transmitted, and further, the developing bias is supplied to the developing sleeve 201 via the bias plate 209.

As described above, the developing sleeve 201 applies the vibration of the helical gear of the drum gear of the photosensitive drum (not shown) to the sleeve gear 2 of the helical gear engaged with the flange 213.
12 is obtained and rotates in a fixed direction. Sleeve gear 212
As shown in FIG. 11, it is designed so that the twisting direction of the teeth is set to the right and the drum gear is driven to rotate the arrow a. By rotating the sleeve gear 212, the thrust force from the nature of the helical gear is received in the direction of arrow b,
The developing sleeve 201 moves while rotating. This amount of movement is due to assembly and individual product tolerances, and is a gap that is absolutely necessary, and corresponds to the gap S after the movement. Now, the developing sleeve 201 has moved by the gap S by the thrust force, but since the bias plate 209 is installed on this moving side, the bias plate 209 has the same structure as in the conventional configuration.
Does not move away from the electrode plate 214, but in the direction in which it is pressed. Therefore, there is no fear of conduction failure due to vibration of the main body of the image forming apparatus, power is reliably supplied, and reliability is improved. Further, the single inspection of the bias plate 209 can be simplified, and the cost of the inspection process can be reduced. Further, since the bias plate 209 is designed on the side where a compressive load acts, there is no fear of deformation even if the bias plate 209 receives a compressive load from the outside.

<Fifth Embodiment> Next, a fifth embodiment of the present invention will be described with reference to FIG. The configuration of the cross section of the developing unit is the same as that of the fourth embodiment, and thus the description thereof is omitted.

In FIG. 12, a flange 213a is fixed to the developing sleeve 201 by press fitting or bonding, and is pivotally supported on the developing device main body 205 via a bearing member 211a. Further, the flange 213a engages with a sleeve gear 212 made of a helical gear. Sleeve gear 212
The helical direction of the helical gear is left and the drive design is such that the drum gear (not shown) is driven to rotate in the direction of arrow a. As a result, the developing sleeve 201 which has been driven receives the thrust force in the direction of arrow b due to the nature of the helical gear of the sleeve gear 212, and the developing sleeve 201 moves by the gap S. A flange 21 is provided on the opposite side of the developing sleeve 201 with which the sleeve gear 212 is engaged.
3b is fixed to the end of the developing sleeve 201 by press fitting or adhesion together with the bias plate 209, and the bearing member 211a.
It is pivotally supported by the developing device main body 205 via. The sleeve gear 212 that has been driven moves by the thrust force in the gap S. At this time, since the contact pressure of the bias plate 209 in contact with the electrode plate 214 is in a more reliable direction, there is no fear of conduction failure due to vibration of the main body of the image forming apparatus, power supply is reliably performed, and reliability is improved.

<Sixth Embodiment> Next, a sixth embodiment of the present invention will be described with reference to FIG. Note that the configuration of the cross section of the developing unit is the same as that of the fourth embodiment, and thus the description thereof is omitted.

In FIG. 13, a flange 213a is fixed to the end of the developing sleeve 201 together with the bias plate 209 by press fitting or adhesion, and is pivotally supported by the developing device main body 205 via a bearing member 211a. Sleeve gear 212
Is engaged with the flange 213a by a spur gear. A flange 213b is also fixed to the other end of the developing sleeve 201 by press fitting or adhesion, and is pivotally supported by the developing device main body 205 via a bearing member 211b. Also, the flange 213
b receives the force from the spring 216 set in the holder 215 fixed to the developing device main body, and in turn pushes the developing sleeve 201 in the direction of arrow b. Therefore, even if the image forming apparatus is subjected to vibrations or the like, the thrust force acts on the side where the bias plate 209 is present, so that power supply failure does not occur and reliability is improved.

[0061]

As described above, according to the first invention of the present application, in the developing sleeve having the sleeve flanges at both ends and the developing device including the magnet roller therein, the shaft portions at both ends of the magnet roller are the sleeves. Since the developing sleeve and the magnet roller do not slide even if the sleeve flange is made of plastic material compared to the conventional developing device, by fixing and holding it in the holder without contacting the flange and the developing sleeve, the sleeve flange is formed. Even if there is a sink mark or the like, uneven rotation and vibration due to the rotation of the developing sleeve are not transmitted to the magnet roller, the distance between the photosensitive drum and the magnet roller is kept constant, and it is possible to suppress the occurrence of image defects such as uneven density. Therefore, according to the present invention, the manufacturing cost can be reduced by forming the sleeve flange from the plastic material. Further, since there is no friction between the sleeve flange and the magnet roller, the magnet roller is not worn and the magnet roller can be reused.

Further, according to the second aspect of the present invention, in the developing device of the image forming apparatus having the magnet roller in the developing sleeve, the step of the cored bar portion of the magnet roller serves as the thrust receiving surface of the magnet roller. The holder for fixing the roller can be designed compact in the longitudinal direction, and the developing device main body itself can be designed compact in the longitudinal direction.

Further, according to the third invention of the present application, by providing the bias plate on the side where the developing sleeve receives the thrust force, it is possible to prevent the conduction failure due to the vibration of the image forming apparatus main body. Further, the management of the spring pressure of the bias plate can be simplified, and the inspection and management costs can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic configuration of a device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a schematic configuration of a developing device in the apparatus shown in FIG.

FIG. 3 is a perspective view showing a schematic configuration of an electrode attached to a flange of a developer carrier in the apparatus shown in FIG.

FIG. 4 is a sectional view showing a schematic configuration of a conventional developing device in which a flange of a developer carrying member and a magnet roller are arranged so as to slide.

FIG. 5 is a cross-sectional view showing a schematic configuration of a device according to a second embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a schematic configuration of a developing device in the device shown in FIG.

7 is a perspective view showing a stepped portion of a shaft portion of a magnet roller in the apparatus shown in FIG.

FIG. 8 is a cross-sectional view showing a schematic configuration of an apparatus of Example 3 of the present invention.

FIG. 9 is a cross-sectional view showing a schematic configuration of a conventional device in which an end surface of a shaft portion of a magnet roller is a thrust receiving surface.

10 is a sectional view showing the magnetic pole arrangement of the magnet roller of the apparatus shown in FIG. 9;

FIG. 11 is a sectional view showing a schematic configuration of a device of Example 4 of the present invention.

FIG. 12 is a cross-sectional view showing a schematic configuration of an Example 5 device of the present invention.

FIG. 13 is a cross-sectional view showing a schematic configuration of a device according to a sixth embodiment of the present invention.

FIG. 14 is a cross-sectional view showing a schematic configuration of a conventional device.

15 is a cross-sectional view showing a schematic configuration of a developer carrier and a bias electrode of the apparatus shown in FIG.

16 is a diagram showing a contact state between a bias electrode and an electrode plate of the device shown in FIG.

FIG. 17 is a perspective view showing a schematic configuration of a bias electrode of the device shown in FIG.

[Explanation of symbols]

 12 developing sleeve (developer carrying body) 15 sleeve flange (flange) 19 magnet roller 100 developing sleeve (developer carrying body) 101 magnet roller 101a, b core metal part (shaft part) 111a, 111b holder (thrust stopping means) 201 Development sleeve (developer carrier) 209 Bias plate (bias electrode) 214 Electrode plate

Claims (8)

[Claims] 1. A developing device including a developer carrying member having a hollow cylindrical shape having flanges at both ends thereof, and a magnet roller contained in the developer carrying member, wherein both ends of the magnet roller are the flanges. A developing device which is supported on the outer side in the axial direction of the developer carrier without contacting the inner wall of the developing device. 2. A process cartridge comprising the developing device according to claim 1. 3. A developing device comprising a hollow cylindrical developer carrying member and a magnet roller which is contained in the developer carrying member and is axially supported by thrust stopping means, wherein the magnet roller has shaft portions at both ends. A developing device, wherein a step portion is provided on the developing device, and the surface of the step portion is pivotally supported so as to serve as a thrust receiving surface that abuts against the thrust stopping means. 4. A process cartridge comprising the developing device according to claim 3. 5. A developer carrying member which rotates in a fixed direction, and a bias which is provided at one end of the developer carrying member and is arranged to contact an electrode plate adjacent to the developer carrying member. A developing device having an electrode, wherein the bias electrode is provided at an end portion of the developer carrier in a direction in which a thrust force is applied to the developer carrier. 6. The gear for rotatably driving the developer carrier is a helical gear, and the bias electrode is provided at an end of the developer carrier in the thrust force direction generated by the helical gear. 5. The developing device according to item 5. 7. A spring member is provided at an end of the developer carrier, and a bias electrode is provided at an end of the developer carrier in a thrust force direction generated in one direction by the spring member. The developing device according to claim 5. 8. A process cartridge including the developing device according to claim 5. Description: