JPH0233253Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic brush device, and more particularly to a magnetic brush device that can be used as a developing device and/or a cleaning device in an electrostatic copying machine.

In an electrostatic copying machine, it is used as a developing device for applying toner particles to an electrostatic latent image formed on a photosensitive member or copy paper to make it a developed image, and also as a developing device for developing an electrostatic latent image formed on a photosensitive member or copy paper, and also as a developing device for developing an electrostatic latent image formed on a photosensitive member or copy paper. In electronic copiers, magnetic brush devices have also traditionally been advantageously used as cleaning devices to remove residual toner particles remaining on the photosensitive member after transfer. Such a magnetic brush device magnetically attracts developer (a so-called two-component developer consisting of toner particles and carrier particles, or a so-called one-component developer consisting only of toner particles) in a pumping area and applies it to the surface. A developer application mechanism is provided for holding and applying such developer to the surface of a workpiece (photosensitive member or copy paper) being moved through the work area. Also, in order to properly perform the developing or cleaning action,
Since it is important to have a predetermined thickness of the layer of developer held on the surface of the developer application mechanism and transported to the working area, a developer application mechanism is provided between the pumping area and the working area. It also includes a spike length setting member for adjusting the thickness of the developer layer held on the surface to a desired value. The developer application mechanism generally consists of a cylindrical sleeve and a permanent magnet disposed within the cylindrical sleeve, and the developer application mechanism generally includes a cylindrical sleeve and a permanent magnet disposed within the cylindrical sleeve. The retained developer is moved along with the movement of the surface of the cylindrical sleeve being rotated, or by the action of a rotating permanent magnet, the surface of the cylindrical sleeve is moved in a direction opposite to the direction of rotation of the permanent magnet. carried. The spike length setting member is composed of a so-called doctor blade-shaped member that extends between the pumping area and the working area toward the surface of the developer holding mechanism and to a position close to this. The thickness of the developer layer held on the surface of the holding mechanism is set to a required value depending on the distance between the tip of the spike length setting member and the surface of the developer holding mechanism.

Magnetic brush devices as described above can perform superior development and/or cleaning operations compared to other forms of development or cleaning devices, as is well known to those skilled in the art. However, conventional magnetic brush devices have the disadvantage that toner particles are scattered from the development zone, and such scattered toner particles can contaminate other components of the electrostatographic copier or the front surface of the brush length setting member (i.e., developer movement). deposits on the surface located on the downstream side of the pumping area), etc.
There is an important problem to be solved (which will be further referred to below with reference to the accompanying drawings).

The present invention has been made in view of the above facts, and its main purpose is to provide a novel method that sufficiently prevents toner particles from scattering from the developing area, thus solving the above problems observed in conventional magnetic brush devices. Another object of the present invention is to provide an excellent magnetic brush device.

According to the present invention, a surface of an actuated member is magnetically attracted to and retained on the surface of a developer material containing at least toner particles in a pumping zone, and such developer material is conveyed to and moved through a working zone. a developer application mechanism for applying the developer to the surface of the developer application mechanism; and a developer application mechanism for achieving a desired thickness of a layer of developer retained on the surface of the developer application mechanism between the pumping area and the working area. A magnetic brush device comprising a brush length setting member, wherein the brush length setting member extends between the pumping area and the working area to a position toward and close to the surface of the developer application mechanism. In addition to the main portion, the main portion has an extension portion that extends toward the surface of the acted member while gradually moving away from the surface of the developer applying mechanism, following the tip of the main portion, and extending toward the surface of the acted member. The distance between the tip of the extension and the surface of the actuated member is 0.5 to 1.5 mm, and the extension of the blade length setting member prevents toner particles from scattering from the working area. A magnetic brush device is provided.

Hereinafter, a specific example of a magnetic brush device constructed according to the present invention will be described in more detail with reference to FIGS. 1 to 3, which illustrate a specific example.

In the illustrated embodiment, the magnetic brush device, designated as a whole by the number 2, is disposed adjacent to a rotating drum 4 (only a portion of which is shown in FIG. 3) disposed within the electrostatic copying machine. Then, a developing and/or cleaning action is applied to the workpiece, which is a photosensitive member attached to at least a part of the surface of the rotating drum 4, which is rotationally driven in the direction shown by the arrow 6 (FIG. 3). carry out.

The illustrated magnetic brush device 2 includes a housing designated generally by the number 8. An opening 10 is formed on the front surface of the housing 8, that is, on the surface facing the surface of the rotating drum 4. As shown most clearly in FIG. 3, the lower portion of the housing 8 constitutes a developer container containing a developer 12, which in the illustrated embodiment is a so-called two-component developer consisting of carrier particles and toner particles. are doing. A developer application mechanism 14, a toner particle supply mechanism 16, and a rotating stirring member 18 are disposed within the housing 8.

The developer application mechanism 14 includes a cylindrical rotating sleeve member 22 that is rotationally driven in the direction shown by an arrow 20 (FIG. 3), and a rolled stationary permanent magnet 24 disposed within the rotating sleeve member 22. It is configured. The developer applying mechanism 14 transfers a portion of the developer 12 present in the developer container to the rotating sleeve member 2 in a developer draw-up zone 26 by the action of a magnetic field generated by a stationary permanent magnet 24.
2 and rotation of the rotating sleeve member 22 transports the developer material 12 held thereon to the working area 28. In the working area 28, the developer 12 held on the surface of the rotary sleeve member 22 passes through the opening 10 formed in the front surface of the housing 8, and the photosensitive material on the rotary drum 4 is rotated in the direction shown by the arrow 6. It is brought into contact with an actuated member which is a member. Thus, the toner particles in the developer 12 are applied to the workpiece, and the electrostatic latent image formed on the workpiece is developed into a visible image (toner image) (the magnetic brush device 2 performs the developing action). when carrying out). Alternatively, the developer 12 held on the surface of the rotating sleeve member 22
The brushing action of the rotating sleeve member on the actuated member and the magnetic attraction action of the magnetic field generated by the stationary permanent magnet 24 remove the toner particles remaining on the actuated member from the rotating sleeve member. 22 (when the magnetic brush device 2 performs a cleaning action).

The direction of rotation of the rotating sleeve member 22, i.e., arrow 2
Viewed in the direction indicated by 0, downstream of the working area 28 is a peeling area 30 where the developer 12 held therein is peeled from the surface of the rotary sleeve member 22. The stationary permanent magnet 24 mentioned above
is not magnetized in the portion corresponding to the separated region 30, and therefore the magnetic field generated by the stationary permanent magnet 24 is significantly weaker or non-existent in the separated region 30. Further, the peeling region 30 is provided with a peeling member 31 whose tip contacts or approaches the surface of the rotating sleeve member 22 . In addition to the fact that the magnetic field is extremely weak or non-existent in the stripping region 30, the tip of the stripping member 31 acts on the developer 12 held on the surface of the rotating sleeve member 22, thereby causing the rotating sleeve member 22 to The developer 12 held on the surface of the rotating sleeve member 22 is peeled off from the surface of the rotary sleeve member 22 in the peeling area 30 . The peeled developer 12 flows down along the peeling member 31 and falls toward the rotating stirring member 18 .

The toner particle supply mechanism 16 includes a toner particle container 32 and a supply roller 34 . The container 32 has a front wall 36, a rear wall 38, and both side walls 40.
(only one of which is shown in FIG. 2), with a toner particle replenishment opening 42 at the top.
is formed, and a toner particle discharge opening 44 is formed at the bottom. The supply roller 34 is rotatably disposed in the toner particle discharge opening 44 and is driven by an electric motor 46 mounted on one side of the housing 8.
(see FIG. 1), it is appropriately rotated in the direction indicated by arrow 48. The lower portions of the front wall 36 and the rear wall 38 of the container 32 are made of an elastic material;
Preferably, the lower edge is brought into elastic contact with the surface of the supply roller 34. As shown in FIG. 2, a large number of notches 50 can be formed in the lower edge of the front wall 36, and a plurality of recesses or grooves can be formed in the surface of the supply roller 34 by knurling or the like. can be formed.

In the toner particle supply mechanism 16 configured as described above, the toner particles 52 are accommodated in the container 32 . Then, when the supply roller 34 is rotated in the direction shown by the arrow 48 by the electric motor 46, the toner particles 52 in the container 32 are moved as shown by the arrow 54 (FIG. 3) in accordance with the rotation of the supply roller 34. It is discharged and supplied to a developer container. On the other hand, the toner particles 52 can be replenished into the container 32 by removing a lid member 56 (FIG. 1) that is removably disposed on the top surface of the housing 8. The container 32 is manually removed through the opening and the toner replenishment opening 42 at the top of the container 32.
This is accomplished by loading toner particles 52 into the container.

As clearly shown in FIG. 2, the rotating stirring member 18 includes a plate-shaped main blade 58 and a plurality of semi-helical auxiliary blades 60 disposed on both sides of the plate-shaped main blade 58.
It can be formed from a rotating stirring blade having. The rotating stirring member 18 is rotated in the direction shown by an arrow 62 in FIG. The toner particles 52 supplied to the container are mixed with the developer 12 present at the bottom of the developer container and stirred, thereby uniformly mixing the carrier particles and toner particles in the developer 12 and triboelectrically charging the toner particles. urge

In the magnetic brush device 2 as described above, the rotating stirring member 18 and the rotating sleeve member 22 of the developer applying mechanism 14 are drivingly connected to a main electric motor (not shown) installed in, for example, an electrostatic copying machine. When the copying process by the electrostatic copying machine is started and the rotary drum 4 is rotated, it is rotated accordingly, and is stopped when the rotation of the rotary drum 4 is stopped. On the other hand, the supply roller 34 of the toner particle supply mechanism 16 is drive-coupled to the above-mentioned dedicated electric motor 46 (FIG. 1), and is operated separately from the rotary stirring member 18 and the rotary sleeve member 22. It is rotated as appropriate in accordance with the execution of the copying process by the machine.

The above-described configuration of the illustrated magnetic brush device 2 is already known and does not constitute an important gist of the present invention. It is omitted in the specification.

As is well known to those skilled in the art, in the magnetic brush device 2 as described above, in order to perform a good developing and/or cleaning action,
Developer 12 held on the surface of rotating sleeve member 22 of developer application mechanism 14 and transported to work area 28
It is important that the layer thickness is appropriate. Therefore, in general, between the developer pumping area 26 and the working area 28, a layer of the developer 12 held on the surface of the rotating sleeve member 22 and carried from the pumping area 26 to the working area 28 has a required thickness. According to the present invention, a spike length setting member with a unique configuration is provided, and the surface of the rotating sleeve member 22 is adjusted by the action of the spike length setting member. held in pumping area 2
In addition to the required thickness of the layer of developer 12 conveyed from 6 to the working area 28, scattering of toner particles from the working area 28 is effectively prevented.

The ear length setting member 64, which has a unique configuration according to the present invention, has a base 64a fixed to a predetermined position at the lower front of the housing 8 so as to be finely adjustable, and a base 64a that extends from the base 64a to the surface of the rotating sleeve member 22. In addition to the main portion 64b extending toward and close to the main portion 64b, the actuated member (therefore, the photosensitive member attached to at least a portion of the surface of the rotating drum 4) extends from the tip of the main portion 64b. an extension 64 extending toward and adjacent to the surface;
It has c. The base portion 64a, the main portion 64b, and the extension portion 64c of the panicle length setting member 64 can be formed from separate pieces and connected to each other, but it is preferable that they are formed integrally as in the illustrated example. preferable.

In the panicle length setting member 64 as described above, the tip of the main portion 64b located close to the surface of the rotary sleeve member 22 performs the panicle length setting function, and is held on the surface of the rotary sleeve member 22 in the working area 28. The thickness of the layer of developer 12 conveyed to the main portion 64b is
and the surface of the rotating sleeve member ₂₂ . On the other hand, the extension part 64c
prevents developer material 12, particularly toner particles therein, from scattering downwardly from work area 28.

In this regard, it should be noted that the conventional magnetic brush device is not provided with the extension portion 64c, and therefore the following problem occurs. If the extension portion 64c is not provided, the toner particles floating downward from the working area 28 are exposed to the affected member (the photosensitive member attached to at least a portion of the surface of the rotating drum 4) and the spike length setting member. 6
4 and the main part 64b of the panicle length setting member 64, and the area shown by the number 66 in FIG.
4b) etc. Also, the distance l ₂ between the lower part of the housing 8 and the surface of the acted member
is relatively large, the toner particles scattered downward from the working area 28 are scattered further downward through the above-mentioned interval l ₂ and diffused into the electrostatic copying machine, damaging various components within the electrostatic copying machine. There is also a risk of contamination.

In order to sufficiently prevent toner particles from scattering from the working area 28, it is important that the extension 64c extends to a position fairly close to the surface of the workpiece, and the tip of the extension 64c and the workpiece The distance l ₃ from the surface is 0.5 to 1.5 mm, preferably 0.8 to 1.2
It is important that the value is mm. In addition, the extension part 64
c represents the center and main portion 64b of the rotating sleeve member 22;
90 to 110 degrees to the straight line connecting the tip of the
Preferably, they extend at an angle α between 95 and 105 degrees. When the angle α becomes 90 degrees or less, a part of the extension portion 64c comes closer to the surface of the rotating sleeve member 22 than the tip of the main portion 64b, and the function of setting the ear length by the tip of the main portion 64b is impaired. It will be done. On the other hand, when the angle α is 110 degrees or more, a considerable distance is created between the extension portion 64c and the surface of the rotating sleeve member 22, and the toner particles that have fallen onto the surface of the extension portion 64c are prevented from hitting the stationary permanent magnet 24. Due to the magnetic attraction effect of the magnetic field thus generated, the toner particles cannot be attracted and held on the surface of the rotating sleeve member 22 again, and therefore, the toner particles accumulate on the surface of the extension portion 64c and form a lump, which is an undesirable phenomenon. will occur.

If toner particles tend to scatter upward from the working area 28 and out of the housing 8, the distance _l4 between the top of the housing 8 and the surface of the workpiece should be set to a sufficiently small value. Just force it.

Although the present invention has been described above in detail in connection with the specific form of the magnetic brush device shown in the accompanying drawings, the present invention is not limited to the specific example shown in the drawings.
It goes without saying that the present invention can be similarly applied to various types of magnetic brush devices.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a specific example of a magnetic brush device constructed according to the present invention. Figure 2 shows the first
FIG. 2 is an enlarged perspective view with a portion of the magnetic brush device illustrated in the figure cut away. FIG. 3 is an enlarged sectional view of the magnetic brush device shown in FIG. 1. 2... Magnetic brush device, 4... Rotating drum, 8
... housing, 10 ... opening formed in the front surface of the housing, 12 ... developer, 14 ... developer application mechanism, 16 ... toner particle supply mechanism, 18 ...
...Rotating stirring member, 26...Developer pumping area, 2
8... Working area, 64... Panicle length setting member, 64a...
...Base of the panicle length setting member, 64b...Main part of the panicle length setting member, 64c...Extension part of the panicle length setting member.

Claims (1)

[Claims for Utility Model Registration] 1. A working device that magnetically attracts and retains a developer material containing at least toner particles on a surface in a pumping region, and transports such developer material to and through the working region. a developer application mechanism for applying to a surface of a member; and a thickness of a layer of developer retained on the surface of the developer application mechanism between the pumping area and the working area to a required value; In the magnetic brush device, the brush length setting member is arranged toward and close to the surface of the developer application mechanism between the pumping area and the working area. In addition to the main part that extends to the position, the main part has an extension part following the tip of the main part and extending toward the surface of the acted member while gradually moving away from the surface of the developer applying mechanism. the distance between the tip of the extension of the member and the surface of the acted member is 0.5 to 1.5 mm;
A magnetic brush device characterized in that scattering of toner particles from the working area is prevented by the extension of the brush length setting member. 2. The developer application mechanism includes a cylindrical sleeve member and a permanent magnet disposed within the sleeve member, and the extension portion of the brush length setting member is located between the center of the sleeve member and the permanent magnet. 90 to the straight line connecting the tip of the main part of the panicle length setting member
The magnetic brush device according to claim 1, which extends at an angle of 110 degrees. 3. The magnetic brush device according to claim 2, wherein the angle is between 95 and 105 degrees. 4. The magnetic brush device according to any one of claims 1 to 3, wherein the distance is 0.8 to 1.2 mm. 5. The actuated member is a photosensitive member attached to at least a portion of the surface of a rotating drum provided in an electrostatic copying machine, and the magnetic brush device includes:
The housing includes a housing having an opening formed in the front face facing the surface of the rotating drum, and the developer application mechanism is disposed within the housing and applies the developer present in the lower part of the housing. a portion of the developer material is magnetically attracted to and held on a surface, and such developer is conveyed and applied to the surface of the photosensitive member through the aperture; , the main portion extends upwardly from the base toward the surface of the developer application mechanism, and the extension portion extends from the tip of the main portion toward the surface of the photosensitive member. A magnetic brush device according to any one of items 1 to 4.