JPS60256169A - Removing method of foreign matter in developer - Google Patents

Abstract

PURPOSE:To remove effectively foreign matter by removing foreign matter from a developer by using magnetic motion effect which operates on only the developer. CONSTITUTION:The developer 8 which is admitted from an introduction path 5 and contains mixed foreign matter is restrained with the magnetic attracting force of a magnet roll 1. The driving state of the magnet roll 1 is so adjusted that a permanent magnet 2 and a sleeve 3 are rotated as shown by arrows O and P respectively; and the rotational frequencies of the permanent magnet 2 and sleeve 3 are so adjusted that the developer attracted on the peripheral surface of the sleeve 3 is carried along the peripheral surface of the sleeve 3 as shown by an arrow Q. Therefore, the rotary motion of the magnet roll 1 operates as the carrying force for the developer 8, which reaches a selecting part 14; and scattering motion is induced with the line of magnetization at the selection part 14 where an alternating magnetic field by the rotation of the permanent magnet 2 and a fixed magnetic field from a fixed magnet 4 cross-links with each other continuously. Then, this motion is induced in only a magnetic material as a component of the developer 8 to select and store foreign matter 13 in a bucket 15 dedicated to the foreign matter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for removing foreign matter from a dry developer, and can be used in electrophotographic recording devices and the like.

[Conventional technology]

In general, recording devices that apply electrophotographic recording technology and electrostatic recording technology form an electrostatic latent image on a latent image forming medium by known means, and correspondingly create a visible image using a developer. This is a series of image-forming processes such as transferring the final image to plain paper, etc., and then fixing it.

The developer used for the above-mentioned visualization is operated so as to be selectively attached to the front surface -1- of the latent image forming medium in one stage of development, and the most typical developing means is Another means that has become widespread is the so-called magnetic brush developing device.

Generally speaking, two types of developers are used in this developing device. There are two types of developers: two-component developers, which include a magnetic material called a carrier and toner bonded to the magnetic material while being mutually triboelectrically charged, and one-component developers, which have a magnetic material mixed into the toner itself.

Izu Jl developers are powders with extremely small particle sizes, which is necessary to reproduce clear, high-resolution images, so if foreign matter gets mixed into these developers, it is necessary to remove this Jl. was extremely difficult.

The above-mentioned foreign matter in the developer refers to substances that have entered the developing device during the series of image-forming processes and have been mixed in and accumulated in the developer, as well as substances that are caused by the developer itself. The former are, for example, paper dust and fiber substances generated from plain paper, which is the final image carrier, and the latter is, for example, when the developer deteriorates due to long-term use or long-term storage. , when the particles become coarse particles that cannot be subjected to development.

It is widely known that these foreign substances accumulate in the developer, and even if they reach a certain number or are extremely small, depending on the shape and size, they can have a significant negative effect on the visualized toner image. ing.

[Problem that the invention seeks to solve]

The above-mentioned negative effects caused by foreign substances in the developer include toner trailing on toner images, white spots that cannot be developed, the appearance of areas, the density of the entire image gradually decreasing, or conversely, the density of fogging. This effect has been confirmed by various phenomena, such as an abnormal increase in

On the other hand, in a developing device containing unused developer mixed with foreign matter, many problems occur due to the structure of the device during continuous development.

For example, in a case where the developer is configured as a magnetic plan, the magnet roll, which is the main element, can become clogged with foreign matter in the gap between the doctor blade that regulates the amount of developer and the magnet roll, preventing normal regulation operation. Of course, there are obvious problems such as running out of the magnetic roll or the inability of the developer around the magnet roll to circulate smoothly, as well as maintenance of the triboelectric charge necessary for the developer to adhere to the image, 3- or electrostatic induction charge. Even basic performance based on electrical factors such as injection is actually hampered.

Therefore, in order to prevent foreign matter from entering the developer, improvements must be made to the parts that generate it, to block the path of entry into the developing device, to improve the durability of the developer itself, and finally, to prevent foreign matter from entering the developer. It is necessary to establish a method to quickly and effectively remove it.

However, even if the source of foreign matter and the route of entry of the foreign matter are repaired as mentioned above, it is currently impossible to completely prevent foreign matter from entering the developer. That is so unrealistic.

In addition, in recent years, as the recording speed of the above-mentioned recording devices has greatly improved, there is a need to reduce the amount of developer consumed, so it has become necessary to collect the developer that has not been transferred onto the final image carrier. Since many examples of devices have been introduced that return this to the developing device, the above-mentioned method becomes even more difficult.

Furthermore, the rate of foreign matter contamination in the developer collected as described above is significantly higher than the rate of foreign matter contamination in unused developer or developer stored in the developing device. This is due to the fact that the rate of contamination of foreign matter is naturally high due to the other work steps in which the developer that has adhered to the latent image forming medium passes through after development. Although the method of removal is extremely important, not only have many proposals not been made, but the reality is that there are only a few effective concrete examples.

[Failure to solve the problem]

Therefore, in the present invention, an alternating magnetic field or a combination of an alternating magnetic field and a fixed magnetic field is used to form a separating section between the two to separate the developer and the foreign matter, and the separating section separates the developer from the foreign matter.

[Effect]

In the above-mentioned sorting section, the lines of magnetic force of the other parties intersect continuously, so that the developer passing through the sorting section has its own magnetism acting on the intersecting lines of magnetic force, causing it to fly, and foreign objects that are not affected by the lines of magnetic force fall. As a result, the two are separated.

In this way, the present invention prevents foreign matter from entering the developer.
Rather than using the unrealistic method of doing so, we have adopted a method that effectively removes the mixed lI¥ from the cylinder.

〔Example〕

Hereinafter, the first aspect of the present invention will be explained based on the drawings. A second embodiment will be explained.

FIG. 1 is a sectional side view showing a first embodiment of the present invention, and FIG. 2 is an enlarged side view of the main part thereof.

In the figure, a magnet roll 1 includes a cylindrical magnetized permanent magnet 2 which is covered with a non-magnetic sleeve 3, and the sleeve 3 and the permanent magnet 2 are relatively rotatable. The fixed magnet 4 is installed at a position close to the magnet roll 1.

On the other hand, the toner introduction path 5 is formed by the cover 6 and the cover 7 and serves to guide the developer 8 mixed with foreign matter to the magnet roll 1. The developer 8 may be obtained either by introducing a part of the developer contained in the developing device, by introducing recovered developer collected into the image forming process, or by a mixture of both. Equivalent to.

Next, the discharge path 9 is formed by an extension of the cover 7 and the cover 10, and is a path through which only the clean developer 11 from which foreign matter has been removed flows out. The barrier 12 contributes to preventing the developer scattered in the discharge path 9 from flowing out of the discharge path 9 by riding on the air current.

The foreign matter 13 in the developer is extracted by the sorting section 14 and falls into a packet 15 to be stored therein.

The first embodiment has the following configuration, and its operation will be explained next.

First, the developer 8 containing foreign matter introduced from the introduction path 5 is restrained by the magnetic attraction force of the magnet roll 1 . Here, the driving state for the magnet roll 1 is set such that the permanent magnet 2 is rotated in the direction of the arrow o, the sleeve 3 is rotated in the direction of the arrow P, and at the same time, the rotation speed of the permanent magnet 2 and the sleeve 3 is is adjusted so that the developing agent 8 adsorbed onto the circumferential surface of the sleeve 3 is conveyed along the circumferential surface of the sleeve 3 in the direction of arrow Q.

Therefore, in this case, the rotational movement of the magnet roll 1 mostly acts as a transporting force for the developer 8, and the developer 8 eventually reaches the sorting section 14.

The sorting section 14 is a place where the alternating magnetic field generated by the rotation of the permanent magnet 2 and the fixed magnetic field generated from the magnetized section of the fixed magnet 4 continuously intersect, and the behavior of the developer 8 here is is a flight motion induced by intersecting magnetic lines of force.

This flying motion of the developer 8 is a phenomenon that is induced only in the magnetic material, which is the fourth component of the developer 8, and when the developer 8 is, for example, the two-component developer, the carrier corresponds to this. , in the case of the above-mentioned -component type developer, the toner itself corresponds to this.

Therefore, in the sorting section 14, the developer 8 is effectively separated from the foreign matter 13 mixed inside by the flying motion. On the other hand, the foreign matter 13 extracted as individual particles falls due to its own weight and is stored in a packet 15 exclusively for foreign matter.

=8= Then, the developer 8 that has continuously performed a flying motion while removing the foreign matter 13 is transferred in the direction of the arrow R, and further deposited in the discharge path 9, and as the clean developer 11 after the foreign matter has been removed, the developer 8 moves in the direction of the arrow R. It is discharged in the S direction.

At this time, the barrier 12 functions to prevent the fine powder of the developer that has not been completely deposited from being carried by the airflow and discharged from the discharge path 9 to the outside of the apparatus. It is formed by

Further, the packet 15 is pulled out at a timely manner to discard the foreign matter 13 contained therein.

The series of steps for sorting out foreign matter 13 has been briefly described above, but the flying motion of the developer 8 mentioned above will be explained in more detail with reference to FIG. 2.

First, regarding the magnet roll 1, the developer 8 described above is used.
This has two roles: to effect the conveyance of the image and to induce flying motion of the developer 8 in the sorting section 14. To specifically carry out this, the following settings are preferable.

It is sufficient that the outer diameter of the sleeve 3 of the magnet roll 1 is equal to or smaller than that normally used in an imager, and for example, a general-purpose magnet roll of 60 to 37 diameter can be used as is. In addition, the number of magnetized permanent magnets 20 is normally about 8 to 16 poles depending on the size of the outer diameter, but it is preferable to have as many magnetized poles as possible, such as 12 or more. The magnetic force strength of the magnetic poles must be at least 400 G or more as an effective value on the circumferential surface of the sleeve. The permanent magnet 2 needs to maintain a rotation speed of about 1100 or more in the direction of arrow O, preferably around 200 orpm, and the sleeve 3 preferably rotates in the direction of arrow P in the range of about 0 to 1100 rpm. It does not matter whether it stops at the top or rotates in the opposite direction to the arrow P. In other words, the conveyance and flying movement of the developer 8 on the magnet roll 1 largely depend on the setting conditions of the permanent magnet 2. means.

Next, the fixed magnet 4 will be explained. The fixed magnet 4 is a permanent magnet having at least one pair of magnetization, and the strength of the magnetic force is required to be about 1000G to 2000G on the magnetized surface. Further, the set position of the fixed magnet 4 is such that the magnetized surface 4a is close to the circumferential surface of the sleeve 3, or close enough to come into sliding contact with a part of the sleeve 3 to form a space for the front 3 (i) sorting section 14.

In the sorting section 14, the lines of magnetic force 4b of the fixed magnet 4 are set to actively intersect with the alternating magnetic field generated by the rotation of the permanent magnet 2.

Based on the above-described specific settings, the developer 8 is first moved by the arrow T on the circumferential surface of the sleeve 3 by the alternating magnetic field of the permanent magnet 2.
The developer chain is conveyed while repeating the rotational movement of the chain. In this state, active movement occurs within the layer of the developer 8, and the developer 8 is sufficiently stirred. Therefore, the foreign matter 13 inevitably tends to float to the surface of the developer 8 layer as foreign matter 13a.

Next, in the sorting section 14, the developer 8 is subjected to rapid magnetic attraction and repulsion due to the intersection of the continuous lines of magnetic force described above, and at the same time, the ability to supply the developer 8 that is sequentially conveyed is also taken into consideration. Then, the sorting unit 14 performs a behavior of leaving the space and flies. -11 On the other hand, the foreign matter 13 that does not participate in the magnetic action in the sorting section 14 is
In particular, the toner component of the two-component developer is removed and falls in the direction of the arrow ■.

Further, the flying direction of the developer 8 indicated by the arrow U is the same as that of the fixed magnet 4.
It changes depending on the strength of the magnetic field intersecting with the permanent magnet 2 and the intersecting period, but in reality it can be changed to some extent relatively easily by just slightly adjusting the direction of the magnetized surface 4a of the fixed magnet 4. This allows the location where the developer 8 is deposited to be changed.

It is more effective in selecting the foreign matter 13 if the flying direction U of the developer 8 makes a larger angle with respect to the falling direction V of the foreign matter 13 .

Next, a second embodiment in which the portion corresponding to the fixed magnet 4 in the first embodiment is partially modified will be described with reference to FIG. 3.

FIG. 3 is an enlarged side view of the main part of the second embodiment, where a major change is that a second magnet roll 16 is installed in place of the permanent magnet 4 described above.

First, the magnet roll 16 has the same mechanism as the first male magnet roll 1 described above, and is composed of a permanent magnet 17 and a sleeve 18. The magnet roll 16 is installed so that the surfaces of the sleeves 3 and 18 of both magnet rolls 1116 are close to each other or in sliding contact with the magnet roll 1, and the space of the sorting section 14 similar to the first embodiment is saved. Form.

It is sufficient that the diameter of the sleeve 18 of the magnet roll 16 is equal to or smaller than that of the sleeve 3, but it is desirable that the number of magnetized permanent magnets 17 is the same as that of the permanent magnets 2, and the magnetic force strength of each magnetized permanent magnet 17 is is preferably higher than the permanent magnet 2, and is required to be about 100 OG or more on the sleeve 1B.

Further, the permanent magnet 17 and the sleeve 18 are driven to rotate in the directions of the arrow W and the arrow X, respectively, but the permanent magnet 17 is magnetically engaged with the adjacent permanent magnet 2 to rotate one of the permanent magnets. As a result, the other one also follows and rotates. The rotation speed of the sleeve 18 is O~
The developer 8 is applied onto the circumferential surface of the assist sleeve 18 at 100 rpm.
If this occurs, the direction of conveyance of this as a whole should be adjusted in the direction of arrow Y.

The behavior of the developer in the sorting section 14 set in this way is such that the alternating magnetic fields generated by the permanent magnets 2 and 17 intersect continuously in the space of the sorting section 14, as indicated by the arrows 9. The developer 8 that has arrived due to the conveying force from the Q direction partially adheres to the sleeve 18 and accumulates in the space of the sorting section 14 .

The developer 8 here rotates in opposite directions on the sleeve 3 side and the sleeve 1B side, as shown in the arrow T and arrow Z directions, and repeatedly collides with each other, causing a space of rapid attraction and repulsion. It cannot be stored completely and flies away from the sorting section 14 in the direction of arrow U at a considerable speed. On the other hand, the foreign matter 13 does not participate in the above-described magnetic action and falls sequentially in the direction of arrow V.

Note that the flying direction U of the developer 8 here is relative to the straight line connecting the axes of the magnet roll 1 and the magnet roll 16.
This direction can also be freely changed by moving the magnet roll 16 left and right along the circumferential surface of the sleeve 3. Furthermore, the flying motion of the developer 8 according to the second embodiment has a much higher dispersion rate than the first embodiment using the fixed magnet 4, and the flying motion of the developer 8 is extremely stable. The movement is carried out, and the effect of extracting the foreign matter 13 is also high.

Incidentally, it is natural that the above-mentioned male and female sides may be incorporated into a developing device or a developer recovery device, for example,
This is the case when the magnet roll 1 and the magnet roll 16 are shared as a developing magnet roll.
Even in such a case, since the above-mentioned principle is adopted, it goes without saying that it falls within the scope of the above-mentioned embodiment.

〔Effect of the invention〕

As explained above, the present invention uses the magnetic movement effect that acts only on the developer to remove foreign matter mixed into the developer, so that most of the foreign matter and deteriorated developer are removed.
For example, spent toner can be effectively removed in the case of a two-component developer, and blocking toner can be effectively removed in the case of a -component developer.

Further, the structure is simple, and if a developing magnet roll is also used as a part of the mechanism as described above, an extremely rational foreign matter removal mechanism can be constructed.

Further, since used developer such as recovered developer can be easily cleaned, the amount of developer consumed in a high-speed recording apparatus can be significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional side view showing a first embodiment of the present invention, FIG. 2 is an enlarged side view of the main part thereof, and FIG. 3 is an enlarged side view of the main part of the second embodiment. 1... Magnet roll 2... Permanent magnet 3...
・Sleeve 4...Fixed magnet 8...Developer 16
...Magnet roll 17...Permanent magnet 18.
...Sleeve Patent Applicant Oki Electric Industry Co., Ltd. Agent Patent Attorney Takashi Kanakura 216- 1. Magnet roll 2. Permanent magnet 3..Sleeve 4. Fixed magnet

Claims (1)

[Scope of Claims] 1. A method for removing foreign matter from a dry developer used in a magnetic brush developing device such as electrophotographic recording technology or electrostatic recording technology, in which the developer is magnetically restrained and assisted. A first magnetic force generating means that generates an alternating magnetic field sufficient for the magnetic force generating means is provided, and a second magnetic force generating means is provided at a position close to the magnetic force generating means. By continuously intersecting the lines of magnetic force possessed by each, a flying motion dependent on the magnetic force is sequentially induced in the developer interposed in the space, causing it to fly, and the developer that does not participate in the flying motion is A method for removing foreign substances from a developer, characterized by separating only foreign substances. 2. A method for removing foreign matter from a developer according to claim 1, characterized in that the second magnetic force generating means is a fixed magnet having two SN poles. 3. A method for removing foreign matter from a developer according to claim 1, characterized in that the second magnetic force generating means is a magnetic force generating means that generates an alternating magnetic field similar to that of the first magnetic force generating means.