JPH10142943A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device where a ghost image due to developing history is solved and the image of high quality without having ununiform density is obtained. SOLUTION: As for the one-component developing device provided with a developer carrier 3 arranged to be opposed to a latent image carrier 1 and carrying developer T housed at the inside of a hopper 2 to a developing area, a developer stirring carrying member 4 provided at the rear part of the developer carrier 3 and supplying the developer carrier 3 with the developer T, a layer forming member 5 forming the layer of the developer T oh the developer carrier 3 and a peeling member 6 peeling the developer T on the developer carrier 3 after passing the developing area: a partitioning member 7 partitioning a first area A storing the developer T for forming the layer supplied to the developer carrier 3 and a second area B temporarily storing the developer T peeled from the developer carrier 3 by the peeling member 6 is provided, and only surfaces of the first and the second areas A and B opposed to the developer stirring carrying member 14 are opened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-component developing apparatus for developing an electrostatic latent image by using a one-component developer, which is used in an electrophotographic copying machine or a printer, and more particularly, to an image recording apparatus for removing an image history by a peeling member. In addition, the present invention provides a one-component developing apparatus that stably obtains high-quality images by sufficiently mixing and circulating the separated developer.

[0002]

2. Description of the Related Art As a developing device using a one-component developer, as shown in FIG. 5, a plurality of magnets are fixed in a hopper 31 containing a magnetic developer T and a rotatable cylindrical sleeve 322. A developer carrier 32 that is arranged and attracts the magnetic developer T onto the sleeve 322 by magnetic force, and a substantially flat soft elastic member fixed to one end of a spring plate member are pressed against the developer carrier 32, And a layer forming member 34 for thinning the transported magnetic developer T (for example, Japanese Patent Application Laid-Open No. 54-51848, Japanese Utility Model Application Laid-Open No. 58-146249).
No. 3,372,675 and U.S. Pat. No. 3,426,730).

[0003]

However, in the above-mentioned developing device, the history of development remains in the developer layer formed on the developer carrier 32, and the ghost image is developed in the next rotation development. Many. This is presumed to be due to the fact that the amount of consumption differs between the image-corresponding region of the developer layer on the developer carrier 32 and the other region, resulting in a difference in the characteristics and amount of the remaining developer. I have. Again, even if the layer is formed by the layer forming member 34, it is not possible to recover the uniform state in about one rotation of the developer carrier 32, and a ghost image is generated in the image area corresponding to the developer carrier 32 area. I have.
Various attempts have been made to improve the developer characteristics and development characteristics as a measure to suppress this history, but the solution has not been fundamentally solved.

On the other hand, as a method of positively eliminating the history, a method of providing a developer peeling member for once peeling and reattaching a developer layer on a developer carrying member after development is provided, for example. An elastic removing plate for removing the developer by pressing against the body is provided, and the elastic removing plate is provided with a plurality of openings through which a lattice-shaped developer passes between the elastic removing plates (for example, Japanese Patent Publication No. 63-67187). Alternatively, for example, while the developer removed from the developer carrying member is passed through the developer peeling member and a plurality of small holes are provided to supply the developer to the developer carrying member again, a burr at the time of processing the small hole is provided. A developing device for preventing image quality from being impaired by catching foreign matter has also been proposed (for example, see Japanese Patent Publication No. 2-15071).

However, since these are provided with an elastic removing plate having a plurality of openings for allowing the removed developer to pass therethrough, in the vicinity of the opening, the separated developer that has passed through the opening immediately carries the developer. The developer adheres again to the body, and new developer from the hopper adheres to other areas on the developer carrier. At this time, a layer formation unevenness estimated to be caused by a difference in characteristics such as a charge distribution and a particle size distribution between the peeled developer and the developer in the hopper occurs,
There is a technical problem that causes image defects such as uneven density and fog instead of a ghost image.

On the other hand, as a solution to this technical problem, as a solution to the problem, the developer removed from the developer carrier is conveyed and collected at a position in the hopper which is farther from the position where the developer is supplied to the developer carrier. It has been proposed to provide a transport mechanism and mix the removed developer with the developer in the hopper without directly touching the developer carrier (for example, Japanese Patent Publication No. 64-32).
However, since the transport path is long and the mechanism is complicated, there is a technical problem that the developer is likely to be clogged in the transport path.

SUMMARY OF THE INVENTION The present invention has been made to solve such a technical problem, and a developer layer on a developer carrier is peeled off once after development, and is further removed from the developer carrier. By thoroughly mixing and circulating the developer with the developer transported from inside the hopper without having a mechanism such as a complicated transport path, the ghost image caused by the development history can be eliminated, and further, uneven density and fog It is an object of the present invention to provide a developing device that can obtain a high-quality image without any problem.

[0008]

That is, according to the present invention, as shown in FIG. 1, a hopper 2
A developer carrier 3 for carrying out the developer T accommodated in the developer carrier to a developing area; and a developer stirring / conveying device provided at a rear portion of the developer carrier 3 and supplying the developer T to the developer carrier 3. A member 4, a layer forming member 5 for forming a layer of developer T on the developer carrier 3, and the developer carrier 3 after passing through a developing area
In the one-component developing apparatus provided with the peeling member 6 for peeling off the developer T, the first region A for storing the developer T for forming a layer to be supplied to the developer carrier 3 and the peeling member 6 A partition member 7 for partitioning from a second region B for temporarily storing the developer T separated from the developer carrier 3 by
Only the surfaces of the first and second regions A and B facing the developer stirring and conveying member 4 are opened.

The peeling member 6 transfers the developer T to the developer carrier 3.
Roll type, brush type,
Blade types and other types are also included. Preferably, an auxiliary stirring and conveying member 8 is provided behind the separating member 6 from the viewpoint of facilitating stirring and conveying of the separated developer and the conveyed developer.

The material and shape of the partition member 7 are not limited as long as the partition member 7 partitions the first area A and the second area B.
Preferably, from the viewpoint of simplifying the configuration of the present invention, it is desirable that the release member 6 is also used. Also, the second area B
From the viewpoint of facilitating the movement of the developer T to the first region A, when the partition member 7 and the developer stirring and conveying member 4 are opposed to each other, it is preferable to secure a certain gap.

The operation of the above technical means will be described. The peeling member 6 peels off the developer T remaining on the surface of the developer carrier 3. At this time, the partition member 7 is in the first area A where the peeled developer stays for the layer forming developer.
Hinders immediate movement. That is, the peeled developer is not immediately used as a developer for forming a layer, but stays in the second region B. On the other hand, since the first area A and the second area B are open on the side facing the developer stirring and conveying member 4, the developer stirring and conveying member 4 is connected to the developer stirring and conveying chamber (developer) of the hopper 2. The developer accommodated in the movable space of the stirring and conveying member 4) is conveyed while being stirred, and the first region A
And into the second area B. The opening in the first area A guides the developer conveyed by the developer stirring and conveying member 4 into the first area A, and the opening in the second area B allows the developer to flow in the second area. Lead into B. At this time, the second area B
When a new developer is transported and introduced from the developer stirring and transporting chamber, the developer in the second area B gradually moves,
The peeled developer and the transported new developer are gradually stirred, and when the peeled developer reaches the vicinity of the opening of the second region B, the developers having different charging properties are mixed. . Accordingly, the peeled developer is circulated to the developer stirring and transporting chamber side in a sufficiently stirred state, and is transported to the first area A by the developer stirring and transporting member 4.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on an embodiment shown in the accompanying drawings. First Embodiment FIG. 2 shows a one-component developing apparatus according to a first embodiment. The developing device according to this embodiment is opened opposite to the photosensitive drum 21 carrying the electrostatic latent image 22 and has a hopper 31 in which the magnetic developer T is stored, and a hopper 31 facing the opening of the hopper 31. Developed roll 32 and hopper 3
1, the developing roll 3 is provided at the back side of the developing roll 32.
A developer stirring and conveying member 33 for conveying the developer to
A layer forming member 34 made of a magnetic material which is disposed opposite to the developing roll 32 to form a developer layer having a predetermined thickness on the developing roll 32;
And a partition member 37 disposed in contact with the developing roller 32 behind the developing area of the developing roller 32 and disposed downstream of the separating member 36 in the rotation direction of the developing roller 32 in contact with the developing roller 32. Have been.

In this embodiment, the hopper 31
The developing roll 32 is disposed so as to cover the developer T from below to above. The inside of the hopper 31 is mainly provided with a developing roll accommodating chamber 311 in which the developing roll 32 is accommodated.
Are separated into a developer storage chamber 312 in which the developer is stored and a developer supply separation chamber 313 secured between the developing roll storage chamber 311 and the developer storage chamber 312.

The developing roll 32 is magnetized with, for example, a plurality of magnetic poles (N..., S...) Having different magnetic and magnetic forces.
Magnet roll 321 fixedly supported by hopper 31
And a non-magnetic cylindrical sleeve 322 that rotates around the magnet roll 321. The sleeve 322 is made of non-magnetic stainless steel, and its surface is processed by a centerless polishing method to a surface average roughness Ra of 0.5 μm or less. In the present embodiment, Ra = 0.
The central value was 2 μm. An AC power supply 41 and a DC power supply 42 are connected to the sleeve 322. In the present embodiment, a frequency of 2.4 kHz peak-to-peak voltage 1800 is used.
V, a DC component of -400 V DC superimposed AC voltage is applied to develop. Here, a photoconductive drum is used as the photosensitive drum 21, and the interval between the developing roll 32 and the photosensitive drum 21 is 250 μm.

The developer stirring / conveying member 33 is, for example, a stirring rod formed integrally with a U-shaped arm portion with respect to the rotation shaft, and moves toward the developing roll 32 while stirring the developer. To be transported. Further, from the viewpoint of improving the developer conveying force, the distal end portion of the developer stirring and conveying member 33 is formed of an elastic member 39. In addition, from the viewpoint of efficiently guiding the developer to the first area A, a developer scraping member 35 is provided at the upper edge of the opening of the first area A so as to face the developer stirring and conveying member 33. Deploy.

The layer forming member 34 is disposed so as to face the developing roll 32 with a gap of 0.2 mm in the vicinity of the magnetic pole closest to the magnet roll 321. In the present embodiment, the magnetic material SUS430 having a plate thickness of 1 mm is used. Made of wood. The reason is that a magnetic developer T containing a larger amount of polyethylene wax / polypropylene wax than the ordinary developer, which is easy to coagulate, is used for the purpose of increasing the fixing strength (such as rubbing resistance). Therefore, developer clogging at the contact portion when the contact layer forming member is used is likely to occur,
In order to avoid such a problem, a non-contact layer forming method using a magnetic member is employed. If a normal developer is used, a contact layer forming member may be used without any problem.

The peeling member 36 includes an elastic rubber roll, a brush roll, a scraping blade, and other types as long as the peeling member 36 is arranged so as to come into contact with the developing roll 32 and peel off the developer T remaining after the development is completed. However, in the present embodiment, an elastic rubber roll is used.

The partition member 37 is provided downstream of the peeling member 36 in the rotational direction of the developing roll 32 and upstream of the layer forming member 34 in the rotational direction of the developing roll 32. Is arranged so that the other end thereof is opposed to the developer agitating / conveying chamber, and when the other end is opposed to the developer agitating / conveying member 33, the position of the leading end is 33 can be secured. Particularly, in the present embodiment, from the viewpoint of facilitating the movement of the developer T from the second area B to the first area A, the partition member 37 and the developer stirring and conveying member 3
3, a certain gap is provided.
Further, in the present embodiment, the partition member 37 is provided integrally with a plate-shaped scraping member 38 which branches off from the middle thereof and whose tip is scraped off the developer adhered to the peeling member 36. Note that the scraping member 38 may be provided separately. As a result, the developer supply / peeling chamber 313 is partitioned into a first area A and a second area B, and each area is opened only on the side of the developer stirring / transfer chamber. Here, the first area A stores the developer for forming a layer to be supplied to the developing roll 32, and the second area B temporarily stores the developer peeled from the developing roll 32 by the peeling member 36. To be stored.

Particularly, in the present embodiment, while the magnetic developer T is being transported to the second region B including the peeling member 36, the magnetic developer T is further transported to the first region A including the layer forming member 34 located above the second region B. In this embodiment, the horizontal position of the partition member 37 is disposed below the rotation center position of the developer stirring / conveying member 33 from the viewpoint of conveying the developer sufficient for forming the layer.

Next, the operation of the one-component developing apparatus according to the present embodiment will be described. That is, when the sleeve 322 of the developing roll 32 rotates, the magnetic developer T that is retained in the first area A with the rotation of the sleeve 322 is attracted and transported according to the magnetic pattern of the magnet roll 321. When the adsorbed developer is passed through the layer forming member 34, the developer is layered on the sleeve 322. When the developer having the layer formed thereon is opposed to the electrostatic latent image 22 on the photosensitive drum 21, a certain amount of the developer is electrostatically electrostatically applied to the electrostatic latent image 22.
Sucked up. On the other hand, the developer remaining on the sleeve 322 is peeled off by the peeling member 36. At this time, the partition member 37 prevents the separated developer from moving to the first region A. That is, the peeled developer is not used immediately as a developer for forming a layer, but stays in the second region B,
It does not immediately adhere to the sleeve 322 of the developing roll 32 as a layer forming developer. On the other hand, the developer stirring / conveying member 33 includes an opening in the first area A and a second area B.
The developer is transported to the opening. At this time, the second area B
Is transported to the opening of the second area B and returned to the hopper 31, or the partitioning member 37 and the developer stirring and transporting member 33 From the gap 61 to the first area A.

Therefore, the peeled magnetic developer T is not immediately used as a layer forming developer, but is used as a layer forming developer after being sufficiently stirred with other developers. In addition to preventing ghosts, image unevenness due to non-uniformity in developer concentration, particle size, etc. can be prevented.

Embodiment 2 Embodiment 2 has substantially the same configuration as Embodiment 1 as shown in FIG. 3, but is characterized in that an auxiliary stirring and conveying member 51 is arranged. The auxiliary stirring / conveying member 51 is located in the second area B including the peeling member 36,
And a stirring rod formed integrally with a U-shaped arm with respect to the rotation shaft. At this time, the auxiliary stirring / conveying member 51 scoops up the magnetic developer T in the rotation direction, the separated developer and the developer conveyed from the developer storage chamber 312 are stirred, and the sufficiently mixed developer is Is conveyed to the opening of the area B of FIG. This facilitates stirring and transport of the peeled developer and the developer transported from the developer storage chamber 312.

Third Embodiment As shown in FIG. 4, the third embodiment has substantially the same configuration as that of the first embodiment, but is characterized in that the partition member 37 also has a peeling function. is there. In particular, in the present embodiment, a thin plate made of phosphor bronze having a thickness of 0.1 mm is configured to be in contact with the developing roll 32. Further, the pressing force applied to the sleeve causes damage to the sleeve and abrasion of the peeling member. From a viewpoint, it is set to 0.05 to 0.25 N / cm ² . This allows
The partition member 37 has not only a partition function of the first and second regions A and B but also a peeling function, thereby simplifying the device configuration.

In the above embodiment, the magnetic developer T
Although the present invention is applied to a developing device using a non-magnetic developer as an example (except for a layer forming member using a magnetic member), the same effect can be obtained. Needless to say,

Further, in the above embodiment, stainless steel (SUS) is used as the sleeve material. However, in the first and second embodiments, a phenol resin is formed into a cylindrical shape, or an aluminum oxide layer or metal is formed on the surface. It goes without saying that the same effect can be obtained even if the present invention is applied to a developing device using a metal sleeve having a resin-based coating film such as plating, acrylic, epoxy, polyester, or phenol.

[0026]

According to the present invention, the developer is peeled from the developer carrier by a peeling member, the first area and the second area are separated by a member that separates the first area and the second area, and the first area and the second area are separated. By opening only the surface facing the developer stirring and conveying member, the peeled developer is not used immediately as a developer for forming a layer, and the peeling developer is used as a developer for forming a layer in the second region. This prevents generation of a ghost image due to the development history, and prevents development unevenness due to non-uniform density and particle size. Further, in the developing device in which the auxiliary stirring and conveying member is provided in the second region of the present invention, the separated and conveyed developer can be easily stirred and conveyed. Further, in the developing device according to the present invention, in which the partition members in the first and second regions also function as the peeling member, the partition member has the partition function in the first and second regions and the peeling function of the developer. And also simplifies the device configuration.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a configuration of the present invention.

FIG. 2 is an explanatory diagram of the one-component developing device according to the first embodiment.

FIG. 3 is an explanatory diagram of a one-component developing device according to a second embodiment.

FIG. 4 is an explanatory diagram of a one-component developing device according to a third embodiment.

FIG. 5 is an explanatory diagram of a one-component developing device according to the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Latent image carrier, 2 ... Hopper, 3 ... Developer carrier, 4
... developer stirring and conveying member, 5 ... layer forming member, 6 ... peeling member, 7 ... partition member, 8 ... auxiliary stirring and conveying member, 21 ... photosensitive drum, 31 ... hopper, 32 ... developing roll (developer carrier), 33: developer stirring / conveying member, 34: layer forming member, 36: separating member, 37: partition member, 51: auxiliary stirring / conveying member, A: first region, B: second region, T ...
(Magnetic) developer

Claims (3)

[Claims] A developer carrier (3) disposed opposite to the latent image carrier (1) for carrying a developer T contained in a hopper (2) to a development area; and a developer carrier (3). 3) a developer stirring / conveying member (4) provided at a rear portion to supply the developer T to the developer carrier (3); and a layer of the developer T on the developer carrier (3). A layer forming member (5);
The developer T on the developer carrier (3) after passing through the developing area
In the one-component developing apparatus provided with a peeling member (6) for peeling off the first region A for storing the developer T for forming a layer to be supplied to the developer carrier (3) and the peeling member (6). ), A partition member (7) for partitioning a second region B for temporarily storing the developer T separated from the developer carrier (3),
The developer stirring and conveying member (4) in the first and second areas A and B
A developing device characterized in that only a surface facing the device is opened. 2. The developing device according to claim 1, wherein a developer T fed from said developer stirring and conveying member (4) and a developer separated from said developer carrier (3) are provided in a second area B. A developing device comprising an auxiliary stirring and conveying member (8) for stirring and conveying the agent T. 3. The developing device according to claim 1, wherein the partition member (7) in the first and second regions (A) and (B) also serves as a peeling member (6).