JPH03216687A - Developing roller and its manufacture - Google Patents

Abstract

PURPOSE:To preclude a toner concentration defect originated from a toner conveyance defect by making an area on a magnet roller which corresponds to a supplementary cutting plate which controls a developer to be supplied to a photosensitive body to substantially '0' gauss. CONSTITUTION:The supplementary cutting plate 8 is arranged between two magnetic poles N2 and S1 and controls a developer X to supply the photosensitive body by a constant amount. The area on the magnet roller 11 positioned below this supplementary cutting plate 8 is set to substantially '0' gauss as shown by a magnetic flux distribution. In this '0' gauss area, the developer X is in a stable state without napping, controlled by the supplementary cutting plate 8, and then supplied to the photosensitive body 7 by a constant amount. Consequently, a development defect due to the toner conveyance defect can be precluded without any quantitative deviation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a developing roller that has a magnetic roller and supplies developer to a photoreceptor, and a method for manufacturing the same.

[Prior Art] Conventionally, a developing device used in an image forming device such as a copying machine is
A stirring roller that stirs the developer and toner, a supply roller that supplies the developer to the developing roller, a developing roller that supplies the developer to the photoreceptor, and an auxiliary plate that regulates the developer adsorbed to the developing roller. It has a toner concentration sensor, etc. As shown in FIG. 6, the developing roller includes a magnet roller 11 and a non-magnetic sleeve 12 on the surface of the magnet roller. This magnet roller 11 has a plurality of magnetic poles N1 and N2 in order to supply developer to the photoreceptor 7.
, Sl, S2, and S3.

Each of the plurality of magnetic poles has the role of attracting and transporting the developer, and forming a magnetic brush in which the developer stands in spikes at the portion approaching the photoreceptor 7. The magnetic flux density distribution is as shown in FIG. There is a compensation plate 8 between the Sl-N2 magnetic poles of this magnetic flux density distribution.

[Problems to be Solved by the Invention] By the way, this auxiliary plate 8 is used to supplement the developer, but the sleeve 12 of the developing roller 6 located under the auxiliary plate
As shown in the figure, the developer on the surface has a magnetic flux density of a predetermined amount rather than O Gauss, so it is in a state of standing spikes. Now, if the humidity, toner viscosity, etc. change, the amount of developer spikes will vary. Therefore, the state in which the developer stands up in spikes is unstable, and the amount supplied to the photoreceptor by the supplementary plate 8 is not the same each time. Therefore, photoreceptor 7
A problem has arisen in that the amount of toner supplied to the printer is not constant.

It is also conceivable that the magnetic poles Sl and N2 may be moved far away from the area on the surface of the sleeve 12 under the auxiliary plate 8 to make the magnetic poles O Gauss so that the developer does not stand up. Due to the influence of the magnetic pole S2 located on the opposite side of the region, the area near the supplementary plate 8 does not reach 0 Gauss.

In addition, since there is variation in the magnetic poles as a manufacturing error, the magnetic flux density may become higher in the region F of the auxiliary plate 8. In this case, the developer will cause spikes even more, so the amount compensated by the compensator plate 8 will differ greatly each time, and the characteristics of the toner supplied to the photoreceptor 7 will no longer be constant. .

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and provides a developing roller in which the area of the magnet roller corresponding to the auxiliary plate is substantially -ho Gauss, thereby preventing poor toner concentration due to poor toner conveyance. is intended to provide.

[Means for Solving the Problems] The present invention provides a developing roller that includes a magnetic roller and supplies developer to a photoreceptor, which corresponds to an auxiliary plate that regulates the developer supplied to the photoreceptor. The magnetic controller is characterized in that the area of the magnet roller is substantially 0 Gauss.

In addition, the invention of the manufacturing method includes magnet} + cola,
A method for manufacturing a developing roller that supplies developer to a photoreceptor. Here, when forming a plurality of magnetic poles for adsorbing developer to predetermined locations of the magnet roller by the magnetic flux density distribution of a plurality of magnetic field generating means, regulating the magnetic flux density distribution by using another magnetic field generating means to make one area of the magnetic roller between the plurality of magnetic poles corresponding to an auxiliary plate for compensating the developer substantially O Gauss; It is characterized by:

[Function] In the present invention, since the area of the magnet roller corresponding to the supplementary plate is substantially EO Gauss, the developer is no longer in a spiky state, and the supplementary plate provides appropriate compensation of the developer. It will be done.

[Examples] The present invention will be described below with reference to drawings showing examples thereof.

FIG. 1 is a schematic cross-sectional view of a developing device using a developing roller according to the present invention.

In general, an image forming apparatus such as a copying machine includes a charging process for charging a photoreceptor, an exposure process for exposing the photoreceptor to form an electrostatic latent image, a developing process for adhering toner to the electrostatic latent image, and a process for removing the developed toner. - Consists of a transfer process to transfer one image onto paper, a fixing process to fix the transferred toner image to paper, and a cleaning process to remove residual toner from the surface of the photoreceptor. The structure of the developing device used in the developing process for adhering toner to the electrostatic latent image is the first one.
It is as shown in the figure. That is, in FIG. 1, a toner replenishing roller 2 for replenishing toner is provided in a diagonal direction t within the developing device l. Below this toner replenishment roller 2, there is developer X sent back from the partition plate 3.
An agitator roller 4 for agitating the toner and the toner from the toner replenishing roller 2 is provided. A supply roller 5 for supplying the developer X stirred by the stirring roller 4 to the developing roller 6 is provided closer to the photoreceptor 7 than the stirring roller 4, and a developing roller 6 is provided close to the photoreceptor 7. It is being

At the upper part of the developing device 1, a spike plate stay 8, a developing slit plate 9, and a toner yield sensor 10 are provided.

As shown in FIG. 2, the developing roller 6 has different types.
Two magnetic poles S3, N2, S1. It is composed of a fixed magnet roller l1 having N1 and S2, and a rotating sleeve roller l2. Further, a supplementary plate 8 is arranged between the two magnetic poles N2 and Sl. This auxiliary plate 8
is compensated for, and a certain amount of fjl image agent X is supplied to the photoreceptor 7. Magnet roller 1 located below this auxiliary plate 8
As shown in the magnetic flux density distribution in FIG. 3, the area No. 1 is substantially 0 Gauss. By setting the developer X to the 0 Gauss region in this way, the developer X is kept in a stable state without causing spikes. Therefore, after being compensated by the compensation plate 8, the developer
is supplied to the photoreceptor 7 in a constant amount.

Next, the operation of this developing roller 6 will be explained.

In FIG. 2, near the Sr3-N2 magnetic pole, the developer X is transferred to the sleeve roller 1 by the magnetic roller 11.
It is adsorbed by 2 tons. Next, the area near the part where the ears are cut from the front side where the developer
Since the magnetic roller 1l is substantially in the 0 Gauss region (between magnetic poles), the developer is transported. Next, the developer X passes through the auxiliary plate 8, is conveyed while being held on the sleeve roller l2, and heads toward the N1 magnetic pole. At the Nl magnetic pole, developer
caress. As a result, the toner is attracted and adsorbed onto the charged photoreceptor 7. Then, in order to direct the developer whose toner concentration has decreased toward the rear, the developer X is conveyed over the sleeve roller l2 by the magnetic pole S2. and S
The developer X is separated between the 2-53 magnetic poles.

Next, a method of manufacturing this developing roller 6 will be described.

The magnet roller 11 is integrally molded from a mixture of magnetic powder and synthetic resin powder.

FIG. 4 is a sectional view of a magnetizing device 15 that simultaneously magnetizes five locations on the molded magnet roller 11 and creates a substantially O Gauss region in one N2-5. In this figure, the soft iron electromagnetic yoke 16a and electromagnetic coil 161) are the parts that magnetize the Nl pole on the magnet roller 11, the soft iron electromagnetic yoke 17a and the electromagnetic coil 17b are the parts that magnetize the Sl pole on the magnet roller electromagnetic yoke 18a
and the electromagnetic coil 18l) are the parts that magnetize the N2 pole on the magnet roller 11, the soft iron electromagnetic yoke 19a and the electromagnetic coil 19b are the parts that magnetize the 83 poles on the magnet roller 1l, and the soft iron electromagnetic yoke 20a and the electromagnetic coil 20l) is a part that magnetizes 82 poles to magnet roller 11. Moreover, the soft iron electromagnetic yoke 21a and the electromagnetic coil 2lb are N-pole or S-pole, and the magnet [I-RA l1 N2-S1
This is provided to create a substantially O-Gauss region between the poles, and regulates the lines of magnetic force when magnetizing the N2 pole and the Sl pole. As shown in FIG. 5, this regulation of the magnetic lines of force is achieved by the soft iron electromagnetic yoke 21a and the electromagnetic coil 2lb attracting the lines of magnetic force between the Sl pole and the N2 pole when the magnetization is shifted, and the lines of magnetic force from the other magnetic pole are attracted. This is done by repelling the magnetic field lines of the magnetic poles.

This soft iron electromagnetic yoke 21a and electromagnetic coil 2 1 1)
By considering the height of the magnet, the distance between the magnetized poles S1 and N2, the magnitude of the current, and the shape, it is possible to optimize the region where the current is substantially 0 Gauss.

As shown in the magnetic flux density distribution in FIG. 3, a substantially 0 Gauss region (arrow A) is formed between the N2-Sl magnetic poles.

In addition, 22 is a magnetic path yoke that connects the magnetic paths of each electromagnetic yoke;
23 is a resin spacer that supports the magnet roller 11.

In this way, the magnet roller 11 after molding is magnetized by the magnetizing device l.
5 and corresponding to each position on its outer circumference, magnetic poles Nl,
N2, Sl, S2, and S3 are magnetized, and in addition, the actual i-to
A Gaussian region is also formed. After the stainless steel shaft l3 is pressed, the magnetized magnet roller 1l is housed and fixed inside the sleeve roller l2 as shown in FIG.

Although the magnet roller has been described as being of a fixed type, it may be of a rotating type.

[Effects of the Invention] In the present invention, since the area of the magnet CI-A corresponding to the auxiliary plate is substantially O Gauss, the developer is
Appropriate compensation is performed by the compensation plate without causing any lag, and there is no quantitative deviation, and development defects due to poor toner conveyance can be prevented.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a developing device using a developing roller according to an embodiment of the present invention, FIG. 2 is a schematic sectional view of a developing roller of the same embodiment, and FIG. , a diagram showing the magnetic flux density distribution of the developing roller of the same example, FIG. 4 is a cross-sectional view of a magnetizing device for manufacturing the developing roller of the same example, and FIG. 5 is a diagram showing the magnetic flux density distribution of the developing roller of the same example.
FIG. 6 is a conceptual diagram showing the magnetization of the developing roller of the same example.
It is a figure which shows the magnetic flux density distribution of the conventional development a-ra. 6...Developing roller 7...Photoreceptor 8...Supplementary plate 11...Magnet roller l5.
...Magnetizing device (magnetic field generating means) X...Developer

Claims (2)

[Claims] (1) In a developing roller having a magnetic roller and supplying developer to a photoreceptor, an area of the magnetic roller corresponding to an auxiliary plate that regulates the developer supplied to the photoreceptor is substantially 0 Gauss. A developing roller characterized by: (2) In a method for manufacturing a developing roller having a magnetic roller and supplying developer to a photoconductor, a plurality of magnetic rollers are used to attract the developer to a predetermined location of the magnetic roller by the magnetic flux density distribution of the plurality of magnetic field generating means. When forming the magnetic poles, another magnetic field generating means is used to make one area of the magnet roller corresponding to the compensating plate for compensating the developer between the plurality of magnetic poles substantially 0 Gauss. A method for manufacturing a developing roller, characterized by regulating magnetic flux density distribution.