JPH08202165A - Method and device for positioning magnetic pole of magnet roller, method and device for assembling developing device, developing device assembled by same, process cartridge with developing device and image forming device with developing device or process cartridge - Google Patents

Abstract

PURPOSE: To provide a method for positioning the magnetic pole of a magnet roller by which the magnetic pole can be highly accurately positioned at a low cost. CONSTITUTION: A hollow magnet roller 19 supported by a supporting shaft 55 is rotated by rotating the supporting shaft 55 by a driving source, then, the peak position of the magnetic force of a developing pole (pole S1) is detected by a magnetic sensor 40, and when the peak position is decided, a supporting member 51 is inserted into a normal assembling position, and then, one side of the hollow magnet roller 19 is supported and fixed by a shaft. Next, by pulling the supporting shaft 55 out of the hollow magnet roller 19, inserting and fixing a supporting member 52, the hollow magnet roller 19 is positioned and fixed. Besides, during this operation, one end of the developing sleeve 12 is supported by a jig at a normal position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic pole positioning method and apparatus for a magnet roller in a developing device used in an image forming apparatus such as a laser beam printer or a copying machine.
The present invention also relates to a method and apparatus for assembling a developing device, a developing device assembled by the method, a process cartridge including the developing device, and an image forming apparatus including the developing device or the process cartridge.

[0002]

2. Description of the Related Art Conventionally, a developing device used in an image forming apparatus, as shown in FIG. 6, is a non-magnetic hollow cylindrical developing sleeve 12 as a developer carrying member and its developing sleeve 1.
It has a bearing 18 for supporting 2 and a magnet roller 19 provided inside the developing sleeve 12. Sleeve flanges 15 and 17 are adhered to the developing sleeve 12, and the bearing 18 includes the sleeve flanges 15 and 17.
Is rotatably supported. Further, the bearing 18 is attached to a holder 21 and holds the developing sleeve 12 in a frame (not shown) via the bearing 18. Further, a sleeve gear 12a is provided in the holder 21 on the one end side, and the rotational drive from a photosensitive drum (not shown) as an image carrier is transmitted to the developing sleeve 12. Then, the magnet 19
Has one end fixedly supported by a holder 21 and the other end pivotally supported by a bearing 22 press-fitted and fixed to a sleeve flange 17, so that the magnetic pole position does not change even when the developing sleeve 12 rotates. ing. Further, the developing sleeve 12 is provided with the bearings 18, 2 from the main body of the image forming apparatus.
A developing bias is applied via the line 2.

In the conventional developing device as described above,
The developing sleeve 12 and the sleeve flanges 15 and 17 are
Both are made by cutting non-magnetic aluminum and are extremely high-precision members. The bearings 18 and 22 are expensive ball bearings for rotating the developing sleeve 12 with high precision.

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 detachably disposed in the main body of the apparatus to facilitate maintenance of the apparatus. In such a process cartridge, a developing device for developing an electrostatic latent image formed on a photosensitive drum as an image carrier through a developer (toner) into A developing roller including a sleeve and a magnet is provided, and the toner in the developing device is supplied to the photosensitive drum by the action of the magnetic force of the developing roller.

This developing roller is disposed in the developing sleeve 100 and a cylindrical developing sleeve 100 which rotates in a fixed direction, as shown in FIG. 7, and a plurality of magnetic poles N1, N2, as shown in FIG. It is composed of a magnet roller 101 having S1 and S2. Magnet roller 1
One end 101a of the core metal part 01 has a shape obtained by cutting a part of the core metal cylindrical part as shown in FIG. 7, and a plurality of magnetic poles are determined for the developing device 110 using the cut flat surface part. It is set to the position. And this core metal part 10
1a is a holder 111 fixed to the developing device main body 110
It is fixed to a. The other end 101b of the magnet roller 101 is fixed to a holder 111b fixed to the developing device main body 110. Also, the developing sleeve 1
00 is a magnet portion 101c of the magnet roller 101
It is arranged so as to cover the magnet roller 101 with a slight gap, and both ends thereof are pivotally supported by the developing device main body 110 via bearing members 102. In this device, the magnet roller 101 is received in the thrust direction by abutting the end surfaces of the magnet roller core metal parts 101a and 101b against the holders 111a and 111b.

Next, a process cartridge of a type different from the above conventional example will be described. As shown in FIGS. 9 and 10, the process cartridge is constructed by rotatably disposing a pipe-shaped developing sleeve 301 in a developing chamber 303. Inside the developing sleeve 301, a magnet having a plurality of magnetic poles is provided. The magnet roller 304 is housed. The developing sleeve 301 is attached to the developing sleeve 301.
The developing blade 302 attached to 05 is in contact.

Further, the developing sleeve 301 has spacer rollers 307a and 307b, which are gap holding members, so as to have a constant gap between the developing sleeve 301 and the photosensitive drum 306 which is an image carrier.
The photosensitive drum 306 is biased by a biasing means (not shown) via the.

A flange 313 is joined to one end of the developing sleeve 301 by fitting it into the inner diameter of the pipe of the developing sleeve 301.
Are supported by bearings 311a. On the other hand, the developing sleeve 3
At the other end of 01, the spacer roller 307b is fitted and attached to the outer diameter as described above, and the outer diameter of the spacer roller 307b is supported by the bearing 311b. On the other hand, the magnet roller 304 is fixedly supported by the developing container 305 with the shaft portion of the end extending.

At one end of the developing sleeve 301,
A sleeve gear 312 for rotating the developing sleeve 301 in a fixed direction is attached to the sleeve gear 31.
2 is driven by a drum gear 316 joined to the photosensitive drum 306 by adhesion, press fitting, or the like, and is rotated in a fixed direction.

Incidentally, these gears are helical gears which can secure a sufficient meshing ratio in order to sufficiently transmit the driving force. This is because by adopting the helical gear, the developing sleeve 301 can be pressed in one direction by utilizing the thrust force of the helical gear when the helical gear rotates.

In this developing device, the position pressed by the helical gear is used as the design reference position of the developing sleeve 301. Explaining with reference to FIG. 10, 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 receives this rotation receives the thrust force generated due to the nature of the helical gear in the direction of the arrow b, and the sleeve gear 312 and the flange 313 make the developing container 3
Move to the surface of 05 and touch. The amount of movement is a tolerance of a single item or a gap required for assembly, and cannot be zero. Also, the developing container 30
This position, which has moved to and is in contact with the surface of No. 5, is the developing sleeve 301.
It is designed as a reference position in the design of.

In the developing device as described above, the toner serving as the developer is supplied to the developing chamber 303 from the toner container (not shown) by the conveying means (not shown) or by dropping the toner from the inlet opening 308 of the developing chamber 303. To be done. 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, and a part thereof is accompanied by the rotation of the developing sleeve 301. Figure 1
0 is conveyed in the direction of the arrow, enters the space between the developing blade 302 and the developing blade 302, and is strongly pressed against the developing sleeve 301 by the developing blade 302 to be charged. It is transported to the outside of 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.

Most of the developing sleeve 301 is made of a conductor such as aluminum alloy, and 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 developing sleeve 3 is released from the developing chamber 303.
The toner conveyed by 01 is blown onto the electrostatic latent image on the photosensitive drum 306 by the developing bias, and the toner develops the electrostatic latent image. The toner that has not been used for development is returned to the developing chamber 303 as the developing sleeve 301 rotates.

The bias plate 309 for applying such a bias voltage, as shown in FIGS. 11 and 12, has claws 309a, 309b, 309 formed on the outer periphery thereof.
It is fixed by coming into contact with the inner peripheral wall of the developing sleeve 301 via c and 309d, 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). (Not shown)
More power is being supplied.

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 the design reference position of the developing sleeve 301 described above.

As described above, various types of developing devices are used in the conventional image forming apparatus, and good developing operation is performed in any of the developing devices.

[0018]

However, in the above-mentioned conventional example, one end of the core bar portion of the magnet roller is cut, for example, by a D-cut, or the magnet roller is rotated by using a polyhedral core bar or the like. Stopping and positioning of the magnetic poles are performed, which increases the number of processes and causes a cost increase. Further, due to manufacturing variations in the D-cut position of the core portion of the magnet roller and the hole-side position where the D-cut penetrates and is positioned, the position of the developing electrode varies depending on the product after assembly.
It was difficult to obtain a certain image quality.

It is an object of a first invention of the present application to solve the above-mentioned problems and to provide a method of positioning a magnetic pole of a magnet roller at a low cost, which enables highly accurate positioning of the magnetic pole.

In addition to the above object, the second invention of the present application aims to provide a method of positioning a magnet roller which can further reduce the cost.

Further, in addition to the above objects, a third invention of the present application aims at providing a method for positioning the magnetic poles of a magnet roller, which can eliminate the variation in the position of the developing pole.

Another object of the fourth invention of the present application is to provide a magnetic pole positioning device for a magnet roller, which is capable of accurately positioning the magnetic poles at low cost.

Further, in addition to the above objects, a fifth invention of the present application aims at providing a magnetic pole positioning device for a magnet roller, which can eliminate variations in the positions of the developing poles.

A sixth aspect of the present invention is to provide a method of assembling a developing device, which can eliminate variations in the positions of magnetic poles even after the developing device is assembled.

A further object of the seventh invention of the present application is to provide a developing device assembling apparatus capable of eliminating variations in magnetic pole position even after the developing device is assembled.

Another object of the eighth invention of the present application is to provide a developing device capable of obtaining a constant image quality without variations in the positions of the developing poles.

Further, the ninth invention according to the present application provides a developing device capable of obtaining a constant image quality without variation in the position of the developing electrode and facilitating maintenance work when the developer is used up. The purpose is to do.

The tenth invention of the present application is capable of obtaining a constant image quality without variations in the position of the developing electrode, and performing maintenance work when the developer is used up, or replacement of the image carrier. It is an object of the present invention to provide a developing device that can be easily maintained during a period.

Further, the eleventh invention of the present application is capable of obtaining a constant image quality without variations in the position of the developing electrode, and performing maintenance work when the developer is exhausted, or the image carrier or the like. It is an object of the present invention to provide a developing device whose maintenance work is easy at the time of replacing the process means.

Further, a twelfth invention of the present application aims at providing an image forming apparatus capable of forming an image having a constant image quality without variations among products.

[0031]

According to the first invention of the present application, the above object is to provide a magnetic pole of a magnet roller enclosed in a hollow cylindrical developer carrier while rotating the magnet roller. Magnetic force of the magnetic pole is detected by a magnetic sensor disposed facing a predetermined position of the magnetic roller, and when the maximum peak value of the magnetic force is detected, the magnetic roller is rotated. This is achieved by stopping the movement and performing the optimum positioning of the magnetic poles.

According to the second invention of the present application,
The above object can be achieved by using the magnet roller formed by the extrusion molding method in the first invention.

Further, according to a third invention of the present application, the above object is the magnetic sensor according to the first invention or the second invention, wherein the magnetic sensor is disposed so as to face a magnetic pole substantially facing the image carrier. Is achieved by using

According to the fourth invention of the present application,
The above-described object is to face a predetermined position where a rotating means for rotating a magnet roller contained in a hollow cylindrical developer carrying member and a magnetic pole arranged in the outer peripheral direction of the magnet roller are positioned. This is achieved by including a magnetic sensor provided and means for controlling the drive of the rotating means according to the output value of the magnetic sensor.

Further, according to the fifth invention of the present application, the above-mentioned object is achieved in the above-mentioned fourth invention by disposing the magnetic sensor so as to face a magnetic pole substantially facing the image carrier. To be done.

According to the sixth invention of the present application,
The above object is to insert the support member from the end portion of the developer carrier after the magnetic poles of the magnet roller are positioned by using the magnetic pole positioning method of the magnet roller according to any of the first to third inventions, This is achieved by fitting the magnet roller and supporting the magnet roller.

Further, according to the seventh invention of the present application, the above object is to support the magnetic pole positioning device for the magnet roller, the magnet roller and the developer carrying member of the fourth invention or the fifth invention. It is achieved by providing a means for inserting the support member from the end portion of the developer carrying member, and supporting the magnet roller at the optimum position after the optimum position of the magnetic pole.

According to the eighth invention of the present application,
The above object is achieved by the developing device assembled by the assembling method of the sixth invention.

Further, according to the ninth invention of the present application, the object is to integrally provide the developing device of the eighth invention and a developer accommodating container for accommodating the developer. It is achieved by making it removable.

According to a tenth invention of the present application, the object is to integrate the developing device of the eighth invention or the ninth invention and the image carrier into an image forming apparatus. This is achieved by making it detachable.

Further, according to the eleventh invention of the present application, in the tenth invention, the above-mentioned object is arranged so as to face the image carrier, and is used as a process means other than the developing device for image forming operation. It is achieved by having at least one.

According to a twelfth invention of the present application, the above-described object is to use the developing device of the eighth invention or the ninth invention or the process cartridge of the tenth invention or the eleventh invention. This is achieved by using the conventional image forming apparatus.

[0043]

According to the first invention of the present application, while rotating the magnet roller contained in the hollow cylindrical developer carrying member, the magnetic pole of the magnet roller is opposed to a predetermined position to be positioned. The magnetic force of the magnetic pole is detected by a magnetic sensor provided in the magnet roller, and the rotation of the magnet roller is stopped when the maximum peak value of the magnetic force is detected. The optimum positioning of the magnetic poles is performed without machining into a D shape or the like.

According to the second invention of the present application,
In the first invention, since the magnet roller formed by the extrusion molding method is used, not only the processing of the end portion of the magnet roller but also the molding process of the body of the magnet roller is simplified.

Further, according to the third invention of the present application, in the first invention or the second invention, since the magnetic sensor disposed facing the magnetic pole substantially facing the image carrier is used, There is no variation in the position of the developing pole.

According to the fourth invention of the present application,
While rotating the magnet roller contained in the hollow cylindrical developer carrying member by the rotating means, the magnetic poles arranged in the outer peripheral direction of the magnet roller are arranged so as to face a predetermined position to be positioned. The magnetic sensor detects the magnetic force and controls the drive of the rotating means so that the output value thereof is maximized to optimize the magnetic pole without processing the end portion of the magnet roller into a D shape or the like. Performs proper positioning.

Further, according to the fifth invention of the present application, in the fourth invention, since the magnetic sensor is arranged so as to face the magnetic pole substantially facing the image carrier, the magnetic pole as described above is provided. The position of the developing pole is positioned with high accuracy by performing the optimum positioning of the. The sixth aspect of the present application
According to the invention, after the magnetic poles of the magnet roller are positioned by using the magnetic pole positioning method of the magnet roller according to any one of the first to third inventions, the support member is inserted from the end portion of the developer carrier. However, since the magnet roller is supported by being fitted in the magnet roller, the magnetic pole position does not vary even after the developing device is assembled.

Further, according to the seventh invention of the present application, the magnetic pole positioning device for the magnet roller of the fourth invention or the fifth invention, and the supporting member for supporting the magnet roller and the developing sleeve are provided at the developing sleeve end. Since the magnet roller is supported at the optimum position after the optimum position of the magnetic pole is provided, the developing device can be assembled without varying the magnetic pole position.

According to the eighth invention of the present application,
Since the developing device is assembled by the assembling method of the sixth invention, there is no variation in the magnetic pole position and a constant image quality can be obtained.

Further, according to the ninth invention of the present application, the developing device of the eighth invention and a developer accommodating container for accommodating the developer are integrally provided, and are attached to and detached from the image forming apparatus. By making it free, not only the maintenance work when the developer runs out but also the constant image quality can be obtained.

According to the tenth invention of the present application, the developing device of the eighth invention or the ninth invention and the image carrier are integrated, and the process is detachable from the image forming apparatus. By using the cartridge, not only the maintenance work becomes easy when the developer runs out or when the image carrier is replaced, but also a constant image quality can be obtained.

Furthermore, according to the eleventh invention of the present application, in the tenth invention, at least one process means other than the developing device, which is disposed so as to face the image bearing member and is used for the image forming operation, is provided. With the process cartridge provided, not only the maintenance work becomes easy when the developer runs out or when the image carrier or the process means is replaced, but also a certain image quality can be obtained.

According to the twelfth invention of the present application, an image forming apparatus using the developing device of the eighth invention or the ninth invention or the process cartridge of the tenth invention or the eleventh invention is provided. Therefore, there is no variation in the developing pole in the developing section, and an image with a constant image quality is formed.

[0054]

Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, the apparatus according to the present exemplary embodiment forms an image on the recording material 202 fed from the feeding unit 201 by the process cartridge 6, and conveys the recording material 202 to the fixing unit 203 to record the recording material 202. Fix the unfixed image on
A discharge tray 20 provided outside the apparatus by the discharge roller pair 204
5 is a laser beam printer that is configured to discharge to 5.

The scanner unit 2 is used to expose the image forming unit.
When the image signal is given to the laser diode (not shown) by the laser diode 06, the laser diode irradiates the polygon mirror 206a with the image light corresponding to the image signal, and the image light reflected by the polygon mirror 206a forms an image. The photosensitive drum 1 serving as an image carrier inside the process cartridge 6 is exposed through a lens (not shown) and a reflection mirror 206b.

That is, the photosensitive drum 1 is rotated in the direction of the arrow, the surface of the photosensitive drum 1 is uniformly charged by the charger 2, and the scanner unit 206 irradiates the image with light to store it in the developer storage unit 11. The supplied toner (developer) T is supplied to the surface of the developing sleeve 12, which is a developer carrier, so that the toner has the same polarity as the charging polarity of the photosensitive drum 1 and substantially the same potential so that the toner adheres to the latent image on the photosensitive drum 1. Is applied to the developing sleeve 12 to develop.

Next, the feeding roller 201b is rotated to separate one recording material 202 in the paper feeding cassette 201a, and the recording material 202 is fed to the photosensitive drum 1 and is closely conveyed to the photosensitive drum 1 to transfer the toner image. The recording material 20 is transferred to the recording material 202.
2 is separated from the photosensitive drum 1 and conveyed to the fixing unit 203.

The fixing section 203 is provided with a fixing roller 211 having a heater H as a heat source therein.
A pressure roller 213 is in pressure contact with the fixing roller 211 and is driven to rotate. Therefore, at the nip portion formed between the pair of rollers 211 and 213, the unfixed toner image is fixed as a permanent image by conveying the recording material having the unfixed toner image under heating while being nipped. Further, the recording material 202 that has been fixed as described above is discharged to the discharge tray 205 by the discharge roller pair 204 and the image formation is completed.

Next, the process cartridge in the above laser beam printer will be described in detail with reference to FIG. In the figure, reference numeral 1 denotes a photosensitive drum which is an image carrier rotating in the direction of the arrow, and around the photosensitive drum 1, process devices such as a charging device 2, a developing device 3 and a cleaning device 4 are arranged. Then, these devices are integrally incorporated in the cartridge container 6a and are detachably provided as the process cartridge 6 in the main body of the image forming apparatus, so that, for example, the photosensitive drum 1 reaches the end of its life or the developing device. When the toner (developer) T in 3 is used up, the entire process cartridge 6 is replaced to facilitate maintenance.

The developing device 3 faces the photosensitive drum 1 and has a developing section 10 having a developing sleeve 12 as a developer carrying member, and a developer which holds toner T therein and supplies 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 against 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 formation.

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.

Next, a method of assembling the developing device 3 according to the present invention will be described with reference to FIGS. As shown in FIG. 3, the magnet roller in this embodiment is a hollow magnet roller 19 formed in a hollow shape, and the hollow inner diameter of the hollow magnet roller 19 has an elastic holding portion 55a.
Has been press-fitted. A support shaft 55 is inserted into the elastic holding portion 55a, and the support shaft 55 is rotatably supported by a bearing 56 outside the container 54. Therefore,
The hollow magnet roller 19 can be rotated by rotating the support shaft 55 using a drive source (not shown).

A sleeve flange 15 is inserted and fixed to the developing sleeve 12 by press fitting, adhesion, caulking or the like in a state in which the hollow magnet roller 19 as described above is included, and the sleeve flange 15 is a supporting member as will be described later. 5
It functions as a bearing when the two are fitted together. 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 press fitting, bonding, crimping or the like, a bearing 18a is engaged with the boss portion thereof, and the sleeve gear 12a is further keyed. It is assembled in a state where rotation is stopped by means such as a set screw. A support member 51 is partially inserted into the sleeve flange 17 as shown by a chain double-dashed line in FIG. 2. In this state, the developing sleeve 12 is axially supported by the support member 51 and is held in a rotatable state. Has been done.

A bias electrode 16 is incorporated in the inner peripheral wall of the developing sleeve 12, and the bias electrode 16
Is made of stainless steel plate for spring and phosphor bronze plate,
As described in the above-mentioned conventional example, the plurality of claw portions are brought into contact with the inner peripheral wall of the developing sleeve 12, and the arm portions are brought into contact with the electrode plate 14 with a predetermined force to establish electrical conduction. The electrode plate 14 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 the developing bias power feeding device ( Power is supplied from (not shown).

A magnetic sensor 40 is disposed so as to face the developing sleeve 12 supported as described above, and the magnetic sensor 40 is, as shown in FIG.
It is accurately positioned and held on an assembling jig (not shown) on a line connecting the center of the developing sleeve 12 and the center of the photosensitive drum 1 serving as an image carrier.

In such a structure, the hollow magnet roller 19 supported by the support shaft 55 is rotated by rotating the support shaft 55 by the drive source, and the magnetic sensor 40 serves as a developing pole (S1 pole). The position where the magnetic force peaks is sought out, and when this is determined, the support member 51 is penetrated to the regular assembly position and the hollow magnet roller 19
Fix one side of the shaft. Therefore, in this state, the hollow magnet roller 19 has the sleeve flange 15
The developing pole position determined by the above is maintained. Next, by pulling out the support shaft 55 from the hollow magnet roller 19 and inserting and fixing the support member 52, the hollow magnet roller 19 is positioned and fixed. In addition,
During this time, the developing sleeve 12 is opened by a jig (not shown).
One end of is supported in a regular position.

As described above, according to this embodiment, the developing pole (S1 pole) of the hollow magnet roller 19 can be positioned with high accuracy.

Further, the control device for the magnetic sensor 40 and the device for rotating the support shaft 55 are interlocked with each other, and the support member 5
By automatically press-fitting 1, 52, the hollow magnet roller 19 can be automatically positioned and configured as an automatic assembly device.

Although the hollow magnet roller 19 is used in the above description, the present invention may use a non-hollow magnet roller 21 as shown in FIG.

As described above, according to the present invention, by using the method of mounting the developing sleeve using the developing pole positioning device, cutting is not required for positioning the magnet roller, and the developing sleeve is easily developed. Can be attached to the container. As a result, it is possible to significantly reduce the cost, and by supporting the magnet roller and the developing sleeve with the same support member, the coaxiality can be significantly improved compared to the case where they are supported by separate parts. The magnetic force on the outer circumference can be stabilized.

[0072]

As described above, the first aspect of the present application
According to the invention, by rotating the magnet roller contained in the hollow cylindrical developer carrying member, the magnetic sensor disposed opposite to the predetermined position of the magnetic pole of the magnet roller is positioned. When the strength of the magnetic force of the magnetic pole is detected and the rotation of the magnet roller is stopped when it is detected as the maximum peak value of the strength of the magnetic force, the steps such as D-cutting of the end portion of the magnet roller are omitted. Therefore, it is possible to supply an inexpensive developing device, process cartridge, and image forming apparatus.

According to the second invention of the present application,
In the first invention, since the magnet roller molded by the extrusion molding method is used, not only the processing of the end portion of the magnet roller but also the molding process of the body of the magnet roller can be simplified and the cost can be further reduced. it can.

Further, according to the third invention of the present application, in the first invention or the second invention, since the magnetic sensor disposed facing the magnetic pole substantially facing the image carrier is used, It is possible to eliminate the variation in the position of the developing pole, and it is possible to obtain a constant image quality.

According to the fourth invention of the present application,
While rotating the magnet roller contained in the hollow cylindrical developer carrying member by the rotating means, the magnetic poles arranged in the outer peripheral direction of the magnet roller are arranged so as to face a predetermined position to be positioned. The magnetic sensor detects the magnetic force and controls the drive of the rotating means so that the output value thereof becomes maximum, so that the D-shaped processing of the end portion of the magnet roller becomes unnecessary, and the development at a low cost is achieved. It is possible to supply the apparatus, the process cartridge, and the image forming apparatus.

Further, according to the fifth invention of the present application, in the fourth invention, since the magnetic sensor is arranged so as to face the magnetic pole substantially facing the image carrier, the magnetic pole as described above is provided. By carrying out the optimum positioning of (1), the position of the developing electrode can be positioned with high accuracy, and a constant image quality can be obtained.

According to the sixth invention of the present application,
After the magnetic poles of the magnet roller are positioned by using the magnetic pole positioning method of the magnet roller according to any one of the first to third inventions, a supporting member is inserted from the end portion of the developer carrying member to the magnet roller. Since the magnet roller is supported by fitting, variations in manufacturing of positioning means such as D-cut do not affect the assembly accuracy, and the optimum developing pole position can be set. It is possible to assemble it to maximize its performance.

Further, according to the seventh invention of the present application, the magnetic pole positioning device for the magnet roller of the fourth invention or the fifth invention, and the supporting member for supporting the magnet roller and the developing sleeve are provided at the end of the developing sleeve. Since the magnet roller is supported at the optimum position after the optimum position of the magnetic pole is provided,
It is possible to position the developing electrode in an optimum manner without variations in the manufacturing of each part of the positioning means such as a cut affecting the assembling accuracy, and it is possible to assemble the product so as to bring out the best performance.

According to the eighth invention of the present application,
Since the developing device is assembled by the assembling method according to the sixth aspect of the invention, it is possible to supply the developing device capable of obtaining a constant image quality without variations in magnetic pole position.

Further, according to the ninth invention of the present application, the developing device of the eighth invention and a developer container for accommodating the developer are integrally provided, and are attached to and detached from the image forming apparatus. By making it free, not only the maintenance work when the developer runs out but also the development device capable of obtaining a constant image quality can be supplied.

According to the tenth invention of the present application, the developing device of the eighth invention or the ninth invention is integrated with the image carrier, and the process is detachable from the image forming apparatus. By using the cartridge, not only the maintenance work can be facilitated when the developer is used up or when the image carrier is replaced, but it is possible to supply a process cartridge capable of obtaining a certain image quality.

Further, according to the eleventh invention of the present application, in the tenth invention, at least one process means other than the developing device, which is disposed so as to face the image bearing member and is used for the image forming operation, is provided. By using the provided process cartridge, not only the maintenance work becomes easy when the developer runs out or when the image carrier or the process means is replaced, but also a process cartridge that can obtain a certain image quality is supplied. It becomes possible.

According to a twelfth invention of the present application, an image forming apparatus using the developing device of the eighth invention or the ninth invention or the process cartridge of the tenth invention or the eleventh invention is provided. Therefore, it is possible to provide an image forming apparatus capable of forming an image with a constant image quality without variations in the developing poles in the developing section.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a laser beam printer according to a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of the process cartridge according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a schematic configuration of a developing device in the device shown in FIG.

FIG. 4 is a sectional view of an apparatus for determining a magnetic pole of a magnet roller according to the first embodiment of the present invention.

FIG. 5 is a sectional view of a developing device using a cylindrical magnet roller according to the first embodiment of the present invention.

FIG. 6 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. 7 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.

8 is a cross-sectional view showing a magnetic pole arrangement of a magnet roller of the apparatus shown in FIG.

FIG. 9 is a cross-sectional view showing a schematic configuration of a conventional example device.

10 is a cross-sectional view showing a schematic configuration of a developer carrier and a bias power source of the apparatus of FIG.

FIG. 11 is a diagram showing a contact state between a bias electrode and an electrode plate of the device shown in FIG.

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Photosensitive drum (image bearing member) 6 Process cartridge 11 Developer container 12 Development sleeve (developer bearing member) 19 Magnet roller 40 Magnetic sensor 51, 52 Support member for developing sleeve and magnet roller

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuaki Odagawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (54) [Title of Invention] Magnetic pole magnetic pole positioning method and device, and development Method and device for assembling apparatus, developing device assembled by the method, process cartridge including the developing device, and image forming apparatus including the developing device or the process cartridge

Claims (12)

[Claims] 1. A magnetic sensor disposed facing a predetermined position of a magnetic pole of the magnet roller while rotating a magnet roller contained in a hollow cylindrical developer carrier. A magnet roller characterized by detecting the strength of the magnetic force of the magnetic pole, and stopping the rotation of the magnet roller when the maximum peak value of the strength of the magnetic force is detected to perform optimum positioning of the magnetic pole. Magnetic pole positioning method. 2. The magnetic pole positioning method for a magnet roller according to claim 1, wherein a magnet roller molded by an extrusion molding method is used. 3. The magnetic pole positioning method for a magnet roller according to claim 1, wherein a magnetic sensor disposed so as to face a magnetic pole substantially facing the image carrier is used. 4. A rotating means for rotating a magnet roller contained in a hollow cylindrical developer carrier and a predetermined position where a magnetic pole arranged in the outer peripheral direction of the magnet roller is positioned. A magnetic pole positioning device for a magnet roller, comprising: a magnetic sensor disposed as a unit; and means for controlling driving of the rotating means according to an output value of the magnetic sensor. 5. The magnetic pole positioning device for a magnet roller according to claim 4, wherein the magnetic sensor is arranged so as to face a magnetic pole substantially facing the image carrier. 6. The method for magnetic pole positioning of a magnet roller according to claim 1, after the magnetic poles of the magnet roller are positioned, a support member is inserted from the end of the developer carrying member, A method for assembling a developing device, comprising: supporting the magnet roller by fitting the magnet roller. 7. A magnetic pole positioning device for a magnet roller according to claim 4 or 5, and means for inserting a support member for supporting the magnet roller and the developer carrier from the end of the developer carrier. An apparatus for assembling a developing device, wherein a magnet roller is supported at the optimum position after the optimum position of the magnetic poles is set. 8. A developing device assembled by the assembling method according to claim 6. 9. A developing device, characterized in that at least the developing device according to claim 8 and a developer storage container for storing a developer are integrally provided and detachable from an image forming apparatus. . 10. At least claim 8 or claim 9.
A process cartridge characterized in that the developing device described in (1) and the image bearing member are integrated with each other so that they can be attached to and detached from the image forming apparatus. 11. The process cartridge according to claim 10, further comprising at least one process means other than a developing device, which is disposed so as to face the image bearing member and is used for an image forming operation. 12. An image forming apparatus using the developing device according to claim 8 or claim 9 or the process cartridge according to claim 10 or claim 11.