JPH08173840A - Separator - Google Patents

Abstract

PURPOSE: To prevent a developer conveyed to a separation part when a magnetic force generating means or the like is stopped from being let alone and being flocculated in a device for conveying and separating a magnetic developer from a lower magnetic force generating means to an upper magnetic force generating means through a mesh. CONSTITUTION: In a separator, magnetic powder replenished to one magnetic force generating means 18 arranged through a mesh 20 given vibration is attracted to the other magnetic force generating means 19 to remove foreign matter from the magnetic powder. Therefore, a driving source 32 for the vibration giving means and a driving source for moving a separation part magnetic pole N19 of the other magnetic force generating means to the opposite position are made those independent of the separator driving source. The OFF timing of driving of a device body, driving of the separator, driving of the vibration giving means and driving of magnetic pole setting action is set as follows: after the driving of the device body and the driving of the separator are stopped, the driving of the vibration giving means is operated for a fixed time, and then the driving of the magnetic pole setting means and the driving of the vibration giving means are stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a separating device for removing impurities mixed in a developer in order to reuse the developer removed from an image bearing member after image formation. It relates to an ON-OFF sequence.

[0002]

2. Description of the Related Art In an electrophotographic apparatus, an electrostatic recording apparatus, etc., when a developer removed by a cleaner after image formation from an image bearing member such as a photoconductor or an insulator is reused, the recovered developer is recovered. Therefore, it is necessary to once perform a reproduction process.

This is because the developer once used for image formation and collected by the cleaner contains paper dust of transfer paper, foreign matters such as dust in the air, agglomerates and coagulated bodies of the developer, If it is returned to the developing device side and reused as it is, defects such as defects and other image defects in the developed image due to such contaminants may lead to deterioration of image quality or scratches on the image carrier. Is generated.

Conventionally, a mesh filter has been proposed as a developer regenerating means. However, the mesh filter may be clogged or small contaminants may be passed through as it is to collect the collected developer. There was a problem in practical use. In particular, if the filter is made fine so as to remove even small contaminants, clogging of the collected developer with the filter becomes noticeable, which creates a trade-off. Further, in Japanese Patent Publication No. 2-11913, in order to further improve the separation performance, a magnetic field is generated along the mesh filter to forcibly suck and convey the magnetic developer, and the contaminants that did not pass through the mesh filter. Proposals have been made to provide a recovery unit for recovering substances, but especially in the case of a recovered developer, once the developer has been used and the developer has deteriorated, it is easy to agglomerate, but contaminants are removed. Since a means for forcibly removing from the filter is not provided, clogging occurs when the developers agglomerate with each other, and the developer and the impurities cannot be completely separated.

Further, in view of the problem, magnetic force generating means are arranged above and below via a mesh, and the collected developer is replenished from the lower side and the magnetic developer attached to the lower magnetic force generating means is passed through the mesh to the upper side. In a device that forcibly conveys and separates to the magnetic force generating means, vibration is forcibly applied to the flexible sheets that sandwich the mesh from above and below, thereby applying vibration to the mesh and destroying the aggregation of the developer. A device for eliminating clogging has been proposed. Then, the control is performed such that the drive OFF timing of the vibration applying means is delayed compared to the drive OFF timing of the magnetic force generating means.

[0006]

However, in the above-mentioned conventional example, the collected developer is replenished from the lower side and the magnetic developer attached to the lower magnetic force generating means is transferred to the upper magnetic force generating means via the vibrated mesh. However, the magnetic developer that has been driven to the separating portion which is just stopped by stopping the drive of the magnetic force generating means is captured by the concentrated magnetic fields of the upper and lower magnetic force generating means. .

Further, when the vibration applying means operates for a certain period of time,
The magnetic developer to be separated is separated and attracted to the upper magnetic force generating means, but since the concentrated magnetic field is still formed, the magnetic developer remains attracted in the vicinity of the opposing separating portion and remains in contact with the mesh. Some have. If left in this state for a long time, the collected developer aggregates as it is, and the mesh is clogged. The collected developer that has once agglomerated has a drawback that the agglomeration cannot be destroyed even if vibration is applied again and clogging of the mesh cannot be eliminated.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and the drive source of the separation device is input from the main body of the device to which the separation device is attached or has an independent drive source. The drive source for the vibration applying means and the magnetic pole position setting operation has a drive source independent of the separation device drive source, and all the drive ONs are performed at the same time. At the drive OFF timing, the drive of the device main body and the drive of the separation device are stopped. rear,
Stop driving the vibration applying means after operating for a certain period of time,
Also, the magnetic pole of one of the magnetic force generating means is rotated and retracted by a set angle to eliminate the concentrated magnetic field of the opposing separation portion after separating the magnetic developer to be separated, and the magnetic developer exists near the mesh. It is configured not to.

[0009]

1 is a schematic sectional view of an image forming apparatus to which the present invention is applied, and FIG. 2 is a sectional view showing the structure of a separating apparatus.
3 is an enlarged view of the vicinity of the mesh for explaining the separation state, FIG. 4 is a side view of the separation device, FIGS. 5 and 6 are explanatory diagrams of a drive system for controlling the magnetic pole position in the separation drive state and the stop state, respectively.
7 and 8 are cross-sectional views of the separator when the concentrated magnetic field in the separator is eliminated, an enlarged view of the vicinity of the mesh, FIG. 9 is a diagram for explaining control timing of the drive system, and FIG. 10 is a diagram for explaining the control system.

Reference numeral 1 designates an image carrier for forming a latent image in the image forming section, 2 a developing unit for developing the latent image on the image carrier 1, 3 a new developer for the developing unit 2 (developer is a magnetic developer). Hopper for feeding the toner, 4 is a transfer separation charger, and 5 is an image carrier 1
A cleaner for collecting the developer remaining on the upper surface, 6 for pre-exposure, 7 for a primary charger for charging the image carrier 1, 8 for an optical system for reading an original image, and 8a for latent image on the image carrier 1. An exposure unit for writing an image, 9 is a document processing device for guiding a document to a reading unit, 10 is a sheet feeding unit for feeding a sheet to an image forming unit, 11 is a conveyor, and 12 is a sheet formed by the image forming unit. A fixing unit that fixes an image, 13 is a sheet discharging unit that discharges a sheet on which an image has been formed, 15 is an intermediate tray that temporarily stores sheets that are once image-formed and then fed to the image forming unit, and 14 is a re-feeding unit. Intermediate tray 1
Refeed sheet guiding section for guiding to 5, and 16 for the intermediate tray 1
5 is a sheet re-feeding unit that feeds the sheets stored in 5 again to the image forming unit.

Next, the separating device will be described. Reference numeral 17 denotes a device frame, which is made of a non-magnetic material (for example, non-magnetic stainless wire,
Mesh made of non-magnetic brass wire, nylon fiber, etc.) 2
0 is arranged substantially horizontally, and the flexible sheet 2 is arranged from above and below.
It is sandwiched by 1 (for example, a thin stainless steel plate). Further, magnetic force sleeves 18 and 19 each having a rotatable cylindrical sleeve having a built-in magnetic force generating means are arranged above and below the mesh 20. There are electromagnets and magnets as the magnetic force generating means, but the magnets are superior from the viewpoint of simplicity of construction and cost.

Regarding the cylindrical sleeve, there are resins, stainless steel, aluminum materials, etc., but aluminum materials are superior in terms of cost and durability. The magnetic sleeve 1
Reference numerals 8 and 19 are rotationally driven in the direction of the arrow by a driving means (not shown). The magnetic forces N ₁₉ and S ₁₈ of the separating portion where the sleeves face each other are set so that N ₁₉ > S ₁₈ .

Vibration is imparted to the flexible sheet 21 by a cam 24 connected to a drive motor 23 attached to a support member 22 for holding the mesh 20, and the vibration is transmitted to the mesh 20 via the flexible sheet 21. To be 25
Is a magnetic plate 26 on the opposite side with a mesh sandwiched by magnets.
Are arranged, and a concentrated magnetic field is formed across the mesh 20.

Reference numerals 27 and 30 denote conveying screws. The conveying screw 27 conveys the developer collected by the cleaner from the rear side to the front side, and the conveying screw 30 conveys the developer from the front side to the rear side to outside the apparatus. And then the developer is re-supplied to the developing device (including the hopper). 28 is a doctor blade that regulates the thickness of the developer layer on the surface of the sleeve 18,
Reference numeral 29 is a scraping blade for scraping the developer from the surface of the sleeve 19.

Reference numeral 31 denotes a non-magnetic brush for scraping off the non-magnetic material remaining on the sleeve 18 together with the residual developer to the collecting portion 32, and at a low speed in the counter direction with the sleeve 18 by a drive system (not shown). It is driven to rotate.

A magnetic pole fixing member 33 is connected to the shaft end 18a of the magnetic sleeve 18 and fixed to the frame body 17. On the other hand, as a facing magnetic pole setting mechanism of the magnetic force sleeve 19, a magnetic pole fixing member 34 is connected to the shaft end 19a of the magnetic force sleeve 19, and a lever 35 and a solenoid 38 that rotate about a shaft 35a are used. When the solenoid 38 is turned on, the magnetic pole N ₁₉ comes to a position facing the magnetic pole S ₁₈ (state of FIG. 2). When the solenoid 38 is off, the magnetic poles of the magnetic sleeve 19 are fixed to the rotationally retracted position (state of FIG. 7) by the positioning portion 37a of the support plate 37 that fixes the coil spring 36 and the solenoid 38 to the frame 17. .

Next, the operation of the image forming apparatus will be described. When a copy operation button (not shown) is pressed, the document in the document processing device 9 is guided to the reading unit, the image of the document is read by the optical system 8, and the image carrier 1 that has been neutralized by the pre-exposure 6 is primary charged. The device 7 is charged to a predetermined potential, and then a latent image is written in the exposure section 8a. Next, the latent image on the image carrier 1 is developed by the developing device 2. At this time, if there is not enough developer in the developing device 2, the developer is appropriately replenished from the hopper section 3.

When the sheet p is fed from the sheet feeding portion 10 to the image forming portion, the developed image on the image carrier 1 is transferred onto the sheet p by the transfer / separation charging device 4 and is fed to the fixing portion 12 by the conveying table 11. The image on the sheet is fixed.
In the case of one-sided copy, the sheet is ejected as it is to the sheet ejection unit 13, and in the case of the double-sided mode or the multiplex mode, it is not ejected as it is, and it is stacked and stored on the intermediate tray 15 by the re-feed sheet guide unit 14, and a predetermined number When the sheets are stored, the sheets are separated and fed one by one by the sheet re-feeding unit 16 and fed again to the image forming unit. When the next document is placed on the platen by the document changing device 9, a second image is formed, the fixing unit 12 fixes the image, and then the sheet is discharged to the sheet discharging unit 13.

The developer on the image carrier 1 which has not been transferred onto the sheet p by the transfer / separation charger 4 is scraped off and cleaned by the cleaner 5. The developer cleaned here is transported to the above-described separating device by a transport mechanism (not shown). The developer scraped off by the cleaner 5 is conveyed to the inside of the separating device by the screw 27 and supplied to the sleeve 18 side.
Here, the developer adheres to the sleeve 18 by a magnetic force, is conveyed upward as the sleeve rotates, and is regulated to a predetermined layer thickness by the doctor blade 28.

Next, the developer sent to the separating portion opposed to the sleeve 19 is turned N by the ON operation of the solenoid 38.
₁₉ is set at a position facing S _18, and is efficiently attracted by the concentrated magnetic field extending from S ₁₈ to N ₁₉ , and the magnetic forces N ₁₉ and S ₁₈ of the separating portion are set so that N ₁₉ > S _18. Therefore, the developer is strongly attracted by N ₁₉ and pulled upward through the mesh 20.

However, the mesh of the mesh 20 only has a gap of several times the particle size of the developer, and in the initial clean state, the developer can smoothly pass through the mesh, but it is durable. As a result, the partially agglomerated developer adheres to the gaps of the mesh 20, and when the environmental humidity is high, the agglutination degree of the developer becomes higher and the mesh does not pass through the mesh. become.

However, in the present invention, the thin flexible sheet 21 (preferably, the thickness is 0.05 to 0.2 mm) is first provided by the cam 24 connected to the drive motor 23.
Since the vibration is applied to the mesh 20 and the vibration is applied to the mesh 20 via the flexible sheet 21, the developer adhering to the mesh 20 is agglomerated by its vibration force and the clogging of the mesh 20 is eliminated. And the developer is easily separated (FIG. 3).

Further, since the mesh 20 is sandwiched by the flexible sheets 21 from above and below, the flexible sheet 21 can be sufficiently restored even when it is bent due to vibration although it is a very thin layer. Therefore, the flexible sheet 21
Can vibrate slightly and transmit the vibration to the mesh 20, and can efficiently vibrate without deforming the mesh 20. In addition, the flexible sheet 21 is 0.0
Since it is a thin layer of about 5 to 0.2 mm, even if it vibrates, its vibration noise is very small and does not radiate noise to the outside.

At this time, the magnetic developer is separated and conveyed from the lower side to the upper side by the magnetic force at the separating portion. However, the developer separated from the magnetic force during the conveyance floats in the container space. However, since the storage chamber in which the upper and lower sleeves 18 and 19 are disposed is closed, the developer does not leak outside.

Since the mesh 20 extends to the vibration applying portion, the separating portion and the vibration applying portion are in spatial communication with each other. However, even if the developer floats in this space and moves to the vibration imparting portion side, the developer is caused by the concentrated magnetic field formed by the magnet 25 and the magnetic plate 26 arranged in the middle as shown in FIG. Are captured and the developer does not reach the vibration imparting portion.

Further, as the durability progresses, the developer further adheres to the magnet 25 and the magnetic plate 26. Since the developer adhered here is a particle having a particle size of about 10 μ, The connected state of the particles is flexible. Therefore, even if the adhered particles contact the mesh 20, the vibration of the mesh 20 is not attenuated, and the vibration imparted by the vibration imparting means is efficiently transmitted to the separation unit.

Further, the separated developer has a small gravity itself, and is set to a magnetic force such that the conveying force by the magnetic force is sufficiently large, so that the developer is easily carried upward and adheres to the sleeve 19. Further, in this embodiment, the developer is set so as to be conveyed from the lower side to the upper side in the direction of gravity so as to be separated. Therefore, the non-magnetic substance (foreign matter) separated from the developer adheres to the lower side of the mesh. However, the vibration applied to the mesh causes it to lose its adhesive force to the mesh and is gravitationally knocked down. Therefore, the developer and the foreign matter can be efficiently separated, and the mesh can be continuously prevented from being clogged.

The separated developer is further conveyed to the downstream side, scraped off from the sleeve 19 by the scraping blade 29, and conveyed outside the separating device by the screw 30. Then, the separated developer is conveyed to the developing system by a conveying device (not shown) and is used for the development again.

The foreign matter that has been separated by the separation unit and has been scraped off falls on the sleeve 18 and is further conveyed together with the residual developer, and is once separated from the sleeve surface by the non-magnetic brush 31 set on the downstream side of the separation unit. Since the non-magnetic brush 31 is in contact with the sleeve 18 with a small contact pressure, foreign matter or the like attached to the sleeve 18 with a weak force can be scraped off, but cannot be completely separated by the separating portion and remains. Since the developer that has stagnated is attracted onto the sleeve by magnetic force, it cannot be scraped off by the non-magnetic brush 31, and is transported to the downstream side to obtain another opportunity for separation. Therefore, the developer is hardly collected in the collecting unit 32, and most of the foreign substances made of non-magnetic material are stored in the collecting unit 32.

As described above, by destroying the agglomeration of the developer and knocking off the foreign matter adhering to the mesh in the direction of gravity, it is possible to suppress the clogging of the mesh portion at all times and continuously and efficiently separate the mesh portion. it can.

Here, in the above embodiment, the separating device (sleeve 18, 19, screw 27, 30, brush 31),
The drive of the transport mechanism (not shown) for transporting the collected developer from the cleaner 5 to the separating device is input from the same main motor (not shown).

Here, each drive source is controlled by the timing shown in FIG. Therefore, when the operation button of the image forming apparatus is turned on, the main motor is driven by the control unit,
The developer collected from the image carrier 1 is conveyed to the separation device by the conveyance mechanism and is used for separation. At this time, mesh 2
The vibration drive motor 23 of 0 and the solenoid for setting the magnetic pole position are also driven by the control unit in synchronization with the main motor, so that the collected developer supplied to the separation unit is immediately separated and transferred to the developing system by the screw 30. Is transported.

When the copying operation is completed, the main motor is stopped by the signal from the control unit. Then, at that time, the collected developer just conveyed to the separation section remains attracted to the upper side by the concentrated magnetic field of the sleeve. However, the vibration drive motor 23 of the mesh 20 is controlled by the signal from the control unit so as to stop after a certain time (α) after the main motor is stopped, so that the collected developer attracted upward by the separation unit is ,
Since the mesh 20 is vibrating, its agglomeration is destroyed, the clogging of the mesh 20 is eliminated, and the developer is easily separated and attracted to the sleeve 19 side.

However, since the concentrated magnetic field at the sleeve facing portion remains set, the magnetic developer remains attracted to the vicinity of the mesh. Therefore, the vibration imparting motor 23
When the solenoid 38 is turned off after the elapse of a certain time (β) after the separation operation by (3) is completed, the magnetic pole of the magnetic sleeve 19 is rotated and retracted by the positioning portion 37a of the coil spring 36 and the support plate 37 that fixes the solenoid 38 to the frame 17. The fixed position (the state shown in FIG. 7) is fixed.

In this state, as shown in FIG. 8, the concentrated magnetic field in the sleeve facing portion is eliminated, and the magnetic developer attracted to the sleeve 19 slides on the sleeve 19 by the rotation operation of the magnetic pole. The magnetic developer on the lower side of the mesh is attracted downward by the magnetic force of the sleeve 18. Also, at this time, since the mesh 20 is still vibrating, this operation is performed more efficiently.

Therefore, even if the main body stops, since the collected developer does not exist in the separated portion of the mesh 20, the mesh 20 will not be clogged due to the aggregation of the developer even when the apparatus is left for a long time. .

In this embodiment, the drive OFF timings of the magnetic pole setting solenoid and the vibration applying means motor are set to α> β.
However, the gist of the present invention is not limited to this relationship, and the magnetic pole setting solenoid operates after the magnetic developer conveyed to the separation facing portion is separated by operating the vibration applying unit for a certain period of time. It is turned off, and the concentrated magnetic field in the separation facing portion is eliminated. Therefore, if the above condition is satisfied, the same effect can be obtained even if α <β.

Further, in the above embodiment, the drive of the separating device is inputted from the main motor of the main body, but the gist of the present invention is not limited to the above embodiment, and for example, each driving source is controlled to separate the separating device. The drive ON timing of the drive motor, the vibration imparting motor, and the solenoid is synchronized with the main body drive main motor, and the developer collected from the image carrier is conveyed and separated (to prevent the developer from staying on the mesh). .

After the image formation, the driving of the separating device is stopped at the same time as the main motor, and then the mesh is vibrated for a certain time (α) to separate the developer in the separating portion, and the predetermined time (β). After the lapse of time, by turning off the solenoid, the concentrated magnetic field of the sleeve facing part is eliminated to prevent the magnetic developer from staying near the mesh. It is to suppress what is done.

In the above embodiment, the driving is turned on at the same time, but it is not always necessary, and it is preferable to turn on the vibration applying means driving, the magnetic pole position setting driving, the separating device and the main body driving. Even if the driving ON timings are slightly different from each other, the magnetic developer is separated as soon as all of them are operated, so that it is not a big problem. It is important to prevent the magnetic developer from accumulating and adhering to the vicinity of the separation mesh while being left for a long time.

Further, although the image forming apparatus has been particularly described in the above-mentioned embodiments, the gist of the present invention is not limited to the image forming apparatus and is also applied to an apparatus for removing foreign matters from magnetic powder. It is a thing.

[0042]

As described above, according to the present invention,
The drive source of the separation device is input from the device body to which the separation device is attached, or has an independent drive source, and the drive source for the vibration imparting means and the separation unit magnetic pole facing setting operation is independent of the separation device drive source. With a drive source, drive ON
Do all at the same time. As a result, the magnetic powder used for separation is separated immediately after being transported. And drive O
The FF timing is such that the drive of the apparatus main body and the drive of the separation device are stopped, and after that, the drive of the vibration imparting means is operated for a certain period of time to separate the magnetic developer, and then the drive of the separation portion magnetic pole facing setting operation and the vibration imparting means By turning off the drive to eliminate the concentrated magnetic field in the facing portion, the magnetic developer does not stay near the mesh. Therefore, even if the apparatus is left for a long time, the mesh does not become clogged due to the aggregation of the developer, and the separation performance can be maintained.

[Brief description of drawings]

FIG. 1 is a schematic main body sectional view showing an embodiment of an image forming apparatus to which the present invention is applied,

FIG. 2 is a cross-sectional view showing the configuration of a separation device according to an embodiment of the present invention,

FIG. 3 is an enlarged view of the vicinity of a mesh for explaining a separated state,

FIG. 4 is a side view of a separation device according to an embodiment of the present invention,

FIG. 5 is a separation driving state of the separation device according to the present invention;
Drive system explanatory diagram for controlling the magnetic pole position,

FIG. 6 is an explanatory view of a drive system for controlling a magnetic pole position when the separation device according to the present invention is in a stopped state;

FIG. 7 is an overall sectional view of the separation device according to the present invention when a concentrated magnetic field is eliminated,

FIG. 8 is an enlarged view of the vicinity of the mesh when eliminating the concentrated magnetic field of the separation device according to the present invention,

FIG. 9 is a diagram for explaining the control timing of the drive system of the separation device according to the present invention;

FIG. 10 is a diagram illustrating a control system.

[Explanation of symbols]

2 ... Developer 5 ... Cleaner 18, 19 ... Sleeve 20 with built-in magnet 20 ... Mesh 21 ... Flexible sheet 23 ... Vibration imparting motor 24 ... Vibration cam 33, 34 ... Magnetic pole fixing member 35 ... Rotating lever 36 ... Coil spring 37a ... Positioning unit 38 ... Solenoid

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G03G 21/10

Claims (1)

[Claims] 1. A magnetic force generating means is arranged oppositely via a mesh filter (mesh) which is vibrated by the vibrating means, and the magnetic powder supplied to one magnetic force generating means generates the other magnetic force. In the separating device that removes the foreign matter from the magnetic powder by suctioning to the means, the driving source for the operation of setting the drive source of the vibration applying means and the separating portion magnetic pole of one magnetic force generating means to the opposing position is the separating device drive source. Is an independent drive source, and the OFF timing of the drive of the device main body to which the separation device is attached, the drive of the separation device, the drive of the vibration applying means, and the drive of the magnetic pole setting operation are A separation device characterized in that after the driving is stopped, the driving of the vibration applying means is operated for a certain period of time and thereafter the driving of the magnetic pole setting operation and the driving of the vibration applying means are stopped.