JPH0211913B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a toner regenerating device.

In electrophotographic devices, electrostatic recording devices, etc., in order to repeatedly use image bearing members (hereinafter referred to as image forming bodies) such as photoreceptors and insulators, residual toner is removed from the surface of the image forming body after image transfer. In order to reuse the toner collected by a cleaning device (cleaner) that removes and cleans the surface of the image forming body as a developer, it is necessary to once recycle the collected toner.

The toner that has been covered and used for development and collected by the cleaner contains foreign matter such as paper dust from the transfer paper, dust in the air, and toner aggregates and coagulation.
If it is returned to the developing device and reused, such impurities may cause other image defects such as chipped areas in the developed image, resulting in a decrease in image quality and causing scratches on the image forming body. It is from.

Conventionally, methods for regenerating toner have been devised, such as those using a mesh filter (mesh) and those using a magnetic cutter, but both clog the collected toner and allow small foreign matter to pass through, making them impractical. There are still problems. In particular, if even small impurities are removed, a trade-off arises in that the collected toner becomes noticeably clogged.

The present invention has been proposed in view of the above, and although it also uses a mesh filter, it allows toner to pass through it smoothly without clogging, improving quantitative throughput, and also reduces the amount of foreign matter. The aim is to provide something that can effectively eliminate

That is, in order to achieve the above-mentioned object, the present invention provides a toner regenerating device that regenerates magnetic toner remaining on an image bearing member removed by a cleaning means by removing non-magnetic materials by passing it through a mesh filter. A magnetic field generating means is provided on a side opposite to the cleaning means with respect to the mesh filter and attracts and conveys the magnetic toner along the mesh filter, and a magnetic toner that is conveyed by the magnetic field generating means and passes through the mesh filter is A toner regenerating device comprising: a collecting section that collects the toner; and a collecting section that collects non-magnetic materials that have not passed through the mesh filter from the magnetic toner transported by the magnetic force of the magnetic field generating means. Essential.

The following description will be made based on illustrated examples. The apparatus illustrated in FIG. 1 has a construction in which a toner regeneration mechanism according to the present invention is incorporated in a collected toner housing of a cleaner.

Reference numeral 1 denotes a drum-shaped image forming body (hereinafter simply referred to as a drum) such as a photoreceptor in electrophotography or an insulator in electrostatic recording, which is rotated in the direction of the arrow. A latent image forming process device, a developing device, and a transfer device are sequentially arranged around the drum 1 in the rotational direction, and the process of latent image formation → development → transfer on the drum surface is executed. Omitted from the figure. In this example, it is assumed that the latent image is developed using a one-component magnetic toner developer.

2 is the remaining toner on the drum surface after passing through the transfer section
This is a cleaner that removes T ₁ and cleans the drum surface for the next image forming cycle.
This shows a method of scraping T ₁ off the drum surface.
There are various other types of cleaners, such as a rotating brush type, an air blowing type, an electrical removal type, and a combination of these types.

Reference numeral 4 denotes a recovery toner housing that accommodates the toner removed from the drum surface. Reference numeral 5 designates a recovery toner housing that accommodates the toner removed from the drum surface, and 5 a magnet roll with N and S magnetic poles magnetized on the surface, which is arranged approximately parallel to the axis of the drum in the housing 4. rotationally driven in the direction. 6 is a fixed sleeve made of a non-magnetic material and has an inner diameter slightly larger than the roll outer diameter and is fitted concentrically on the outside of the rotating magnet roll, and 7 is excluding the lower approximately 1/4 circumferential surface of the fixed sleeve. A non-magnetic sheet (or film) made of synthetic resin, non-magnetic metal, paper, etc. is closely attached along the other 3/4 circumferential surface, and the right side of the sheet 7 in the drawing is on the bottom surface of the housing 4. The left side extends along the bottom surface and the inner surface of the left side wall of the housing 4 to form a recycled toner collection gutter groove ₇₂ having _a substantially semicircular cross section. Reference numeral 8 denotes a mesh screen which is disposed along the arc from the right side to the upper surface of the sleeve 6 to which the sheet 7 is tightly attached, and is slightly lifted from the surface of the sheet 7, and its right side extends and is fixed to the bottom surface of the housing 4. , the left side extends from a slit opening provided in the middle of the left side wall of the housing 4 to the outside of the housing, and the extended portion 8 ₁ is bent upward and fixed to the outer surface of the left side wall of the housing 4 . The mesh screen 8 has mesh openings that are 5 to 50 times larger than the toner particle diameter used.

Reference numeral 9 denotes a screw conveyor for carrying out toner provided in the recycled toner collection gutter groove ₇₂ .

In the above configuration, the transfer residual one-component magnetic toner _T1 on the surface of the drum 1 scraped off by the cleaning blade 3 falls and accumulates in the wedge-shaped space 10 formed by the drum 1 and the mesh screen 8 along the sleeve. The collected toner _T2 receives the magnetic force of the magnet roll 5 in the sleeve 6 through the sleeve 6, sheet 7, and mesh screen 8, and is transferred to the roll 5 by the magnetic field gradient based on the continuous rotational drive of the magnet roll 5 in the arrow direction. It crawls up the outer surface of the arcuate mesh screen 8 along the sleeve 6 from the right side to the upper surface along the arcuate surface by receiving a conveying force in a direction opposite to the rotational direction of the screen.

The arc-shaped mesh screen 8 of this recovered toner T ₂
During the conveyance process along the surface, the toner passes through the holes of the screen 8 and falls onto the surface of the sheet 7 on the outer circumferential surface of the sleeve.
The falling toner T ₃ is also Magnetstrol 5
The toner is attracted and held on the surface of the sheet 7 by the magnetic force of the toner, and is continuously conveyed along the surface of the sheet 7 in a direction opposite to the direction of rotation of the roll 5 due to the magnetic field gradient based on the rotation of the magnet roll 5.
Enter ₂ and accumulate.

When the collected toner T ₂ is transported along the screen 8 surface, (a) paper powder between the collected toner T ₂ in the wedge space 10;
Non-magnetic contaminants such as dust in the air are not transported because they do not receive the transporting force from the magnetic field.

(b) Even if the paper powder, dust, etc. are mixed with the transported toner layer and transported together, they are subjected to a moving force in the surface direction of the mesh screen 8 together with the toner layer T ₂ , so that the mesh screen 8 is substantially It acts as a small particle and does not pass through the screen, but is removed from the layer T ₂ due to the fluid movement of the layer T 2 during conveyance, mutual brushing of the conveyed toner layers T ₂ and T ₃ on the sheet 7 side and the screen ₈ side, etc. It rises to the surface side of layer T ₂ , separates from layer T ₂ , and falls into wedge space 10 .

(c) Aggregates and coagulated bodies of toner that are large enough to overcome the conveying force of the magnetic field are not conveyed.

(d) Even if the toner layer T ₂ is mixed with the transported toner layer T 2 and transported, there is a loosening effect due to fluid movement of the transported toner layer T ₂ , rubbing movement of the transported toner layer T 2 against the mesh screen surface, mutual brushing of the transported toner layers T ₂ and T ₃ , etc. during the transport process. The agglomeration and coagulation are broken and the toner becomes a fine powder. Also, like the paper powder and dirt in item (b), those that cannot be loosened will not pass through the openings of the screen 8 (in other words, if the conveyance is in the direction along the surface of the screen 8, the screen 8 will have substantially smaller openings). ), it floats to the surface side of layer T ₂ and is separated from layer T ₂ and falls into wedge space 10 .

(e) Untransported paper powder and dirt accumulated in the wedge space 10 in item (a), and items separated and fallen from layer T ₂ in item (b),
The large toner aggregates/coagulates that are not transported in item (c) and those that have separated and fallen from the layer T ₂ in item (d) are from the gap 3 between the drum 1 and the mesh screen 8 at the bottom of the wedge space 10 to the lower part of the wedge space. are naturally dropped and discharged into the housing space ₄₁ .

In this way, only the fine powder of toner passes through the holes of the screen 8 and falls onto the sheet 7 surface on the outer circumferential surface of the sleeve, and the falling toner _T3 also forms a groove along the sheet 7 surface based on the magnetic field gradient of the rotating magnet roll 5 _. The recycled toner T ₃ containing no contaminants is collected in the groove 7 ₂ . Therefore, the recycled toner _T3 is sequentially carried out by the carry-out screen conveyor 9 and returned to the developing device for reuse.

In this case, the openings of the mesh screen 8 are 5 to 50 times larger than the particle size of the toner, so fine toner powder passes smoothly through the openings of the screen without causing clogging, and the quantitative throughput is greatly increased. improves.

The mesh size of the mesh screen 8 was determined through experiments. In other words, the particle size of the toner used,
There is a strong correlation between the mesh size (opening diameter) of the mesh screen 8, the degree of clogging, and the impurity removal effect. If the aperture diameter is small, the ability to remove foreign matter will improve, but it may cause clogging, and the amount of toner passing through it will decrease, resulting in a decrease in quantitative throughput. There is a qualitative relationship in which the amount of toner passing through increases without causing any problems, but the ability to remove foreign matter decreases. Therefore, through various experiments, we quantitatively determined the opening diameter range of the mesh screen 8 that satisfies both the practical quantitative processing capacity and the impurity removal capacity in relation to the toner particle size, and determined that the opening diameter range of the mesh screen 8 was 5 to 50 times the above. By using a mesh screen 8 having an opening diameter within this range, and transporting or making the toner to be recycled along this screen surface in a fluid state, there will be no clogging problems, and there will be no trouble. This makes it possible to substantially and sufficiently remove impurities.

To explain with a specific example, in the apparatus illustrated in FIG. Under the conditions, the mesh screen 8 to be used has a toner particle diameter of 12μ, and the opening diameter of the mesh is 1x = 12μ, 2.5x = 30μ, approximately 4.1x = 50μ, 5x = 60μ, approximately 8.3x = 100 , approximately 16.6 times ≒
200, 25x = 300x, approximately 33.3x ≒ 400μ, approximately 41.6x ≒
The amount of clogging and the amount of foreign matter (impurities) removed were investigated for 500 μ, 50 times = 600 μ, and approximately 58.3 times ≒ 700 μ. The results are shown in the graph of Figure 2. In other words, the degree of clogging decreases as the opening diameter of the mesh screen 8 increases, as shown by the dotted line curve (A), but the amount of impurities removed decreases as the opening diameter increases, as shown by the solid line curve (B). In practical terms, the opening diameter of the mesh screen 8 is set in the range of 60 to 600μ, which is 5 to 50 times larger than the toner particle size of 12μ, in consideration of the degree of clogging and the degree of removal of foreign matter. It is better to
If it is less than 60μ, toner clogging will increase and the quantitative throughput will be greatly reduced, and if it is more than 600μ, impurities that will be a substantial obstacle will pass through, and the toner regeneration effect will be lost.

FIG. 3 shows the size of the opening diameter of the mesh screen 8 and the state in which the recovered toner storage space ₄₂ of the apparatus illustrated in FIG. 1 is filled with toner (overflowing) when the image forming apparatus is operated continuously. The number of copies (dash line curve C) at the time when the condition (state) is reached is investigated, and the number of copies at the time when image fraying occurs due to impurities remaining in the recycled toner without being removed (solid line curve D) are investigated. That is, if the opening diameter of the mesh screen 8 is small, the quantitative capacity of toner regeneration processing due to clogging decreases, and the recovered toner storage space ₄₂ of the apparatus illustrated in FIG. 1 becomes full at an early stage of continuous copying. Put it away. Furthermore, if the opening diameter of the eye is large, the ability to remove impurities will be reduced, and image chipping problems will also occur in the early stages of continuous copying due to impurities remaining after removal in the recycled toner. If it is within the above eye aperture diameter range, the eye aperture diameter is set to the minimum limit, that is, in this example, 60μ, which is five times the toner particle size of 12μ, or 600μ, which is 50 times the maximum limit. Even if set to 8000 at least
It is possible to take continuous photographs of up to 100 pages without any trouble.

On the other hand, the conventional mesh method, which uses a mesh screen with an opening diameter approximately the same as the toner particle diameter, and simply passes the recycled toner through the screen and performs the meshing process, produces 1000 continuous copies. In addition, in the rotating magnetic blade method, clogging occurs in the gap after continuous copying of about 300 to 5,000 sheets, requiring frequent cleaning of the mesh screen and gap.

Note that the toner to be recycled along the surface of the mesh screen 8
As a conveying means for T ₂ , a potential generating electrode 12 is disposed on the circumferential surface of an insulating roll 11 instead of the magnet roll 5 in the sleeve 6 in the apparatus illustrated in FIG. Based on the potential gradient generated in the mesh screen by continuous rotation in the same direction as the magnet roll 5 shown in the figure, the recycled toner _T2 in the wedge space 10 is subjected to a conveying force as in the case of the magnet roll 5, and the arc-shaped mesh Climb up the outer surface of screen 8. In this case toner T ₂
can be transported even if it is not magnetic.

Further, even if the mesh screen 8 is in the form of a horizontal plane and the toner to be recycled is conveyed along its upper surface by magnetic or electrical means, effective toner regeneration processing can be performed. That is, even if the opening diameter of the mesh screen 8 is 5 to 50 times larger in relation to the toner particle diameter as described above, the foreign matter in the recycled toner moves along the surface of the screen. The screen essentially acts as a small mesh so that the toner does not pass through the screen, and due to the flow of the recycled toner as it is conveyed, it floats onto the top surface of the recycled toner layer that is being conveyed and is separated, leaving only the toner as a fine powder. passes through the eyes of the screen. Contaminants separated and raised on the upper surface of the toner layer to be recycled may be removed out of the screen surface by blowing a cross wind or the like, or they may be subsequently conveyed on the screen surface and removed out of the screen surface.

Furthermore, even if a flat mesh screen is installed at an angle and the recycled toner is allowed to flow down the inclined surface from top to bottom, contaminants are separated by the above principle, and only the fine toner particles reach the screen surface. It passes through the bottom and falls, yielding recycled toner.

Moreover, it goes without saying that the apparatus may be constructed as an independent apparatus without being incorporated into the cleaner 2 like the apparatus illustrated in FIG.

In the apparatus illustrated in FIG. 1, the sheet 7 covering the outer surface of the sleeve 6 is used to smoothly guide the recycled toner T ₃ that has passed through the mesh screen 8 to the discharge screw conveyor 9. The recycled toner that has passed through the screen 8 is conveyed directly along the outer surface of the sleeve 6 to the conveyor section 9.
At this time, the recycled toner on the sleeve surface 6 may be collected from the sleeve surface using a scraping blade.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional side view of one embodiment of the present invention, and FIG.
3 is a graph showing the regeneration ability, and FIG. 4 is a cross-sectional side view of a rotating insulating roll equipped with potential generating electrodes serving as electrical conveyance means. 1 is an image forming body, 3 is a cleaning blade,
4 is a collected toner housing, 5 is a magnet roll, 6 is a sleeve, 7 is a sheet covering the sleeve surface, and 8 is a mesh screen.

Claims (1)

[Scope of Claims] 1. In a toner regenerating device that regenerates magnetic toner remaining on an image carrier that has been removed by a cleaning means by passing it through a mesh filter to remove non-magnetic substances, a magnetic field generating means that is provided on the opposite side of the cleaning means and that attracts and conveys the magnetic toner along the mesh filter; and a collection section that collects the magnetic toner that has been conveyed by the magnetic field generating means and has passed through the mesh filter. A toner regenerating device comprising: a collection unit that collects non-magnetic materials that have not passed through the mesh filter from the magnetic toner transported by the magnetic force of the magnetic field generating means.