JPH052321A - Developing device - Google Patents

Abstract

PURPOSE:To prevent the flocculated lump of a developer from being formed and to surely execute sealing even when the dispersion of a member is found by supplying the developer to a non-image area less than the image area of a middle part which contributes to forming an image. CONSTITUTION:A scraper blade 5 is allowed to about on the surface of both ends, which slide over the non-image area of a developing sleeve 2 among the surfaces of a supplying and peeling roller disposed to slide over the sleeve 2. Then, a developer supplying means 4 sets so that the developer 3 may be supplied to the non-image area of both ends of the developer carrier 2 which does not contribute to forming the image less than the image area of the middle part of the developer carrier 2 which contributes to forming the image out of the area that the developer 3 is supplied to the developer carrier 2. Therefore, the quantity of the developer around an end sealing member 10 disposed in the non-image area or on the end side further than the non-image area is reduced, and sealing is surely performed even in the case of setting such simple constitution that the end face of the end sealing member 10 is just adhered to the end face of the peripheral member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device in an image forming apparatus such as an electrophotographic copying machine, an electrostatic recording machine and a magnetic recording machine, and more particularly to a developing apparatus having an improved developer sealing function.

[0002]

2. Description of the Related Art Conventionally, various apparatuses have been proposed as a dry type one-component developing apparatus using a dry type non-magnetic one-component developer and have been put into practical use. The configuration is as shown. That is, the developing sleeve 2 serving as a developer carrier is arranged so that the supplying / peeling roller 4 serving as a developer supplying / separating means slides in the hopper 1 serving as a developer container. Developer 3
And the developer 3 left undeveloped on the developing sleeve 2 is peeled off. An elastic blade 8 is arranged so as to contact the surface of the developing sleeve 2 at a position downstream of the sliding portion between the supply / peeling roller 4 and the developing sleeve 2 in the rotation direction of the developing sleeve 2. . The elastic blade 8 forms a uniform thin layer of the developer 3 supplied on the developing sleeve 2 by the supply / peeling roller 4 at its abutting portion, and the developer has a charge amount necessary for development. 3 is charged.

Further, in the above-mentioned conventional apparatus, the end seal members 10 are attached to both ends of the developing sleeve 2 to prevent the developer from leaking. In particular, when a non-magnetic one-component developer is used, it cannot be constrained by a magnetic force unlike magnetic developers, so that prevention of developer leakage is an important issue. FIG. 9 is a diagram showing an example of a conventional sealing method, in which the elastic blade 8 is formed at the end of the developer application area formed with a width wider than the image area.
The end surface of the end seal member 10 is brought into contact with the end seal member 10 for sealing.

However, in such a sealing method, the width of the elastic blade 8 or the end seal member 10 or the mounting position of the elastic blade 8 varies in manufacturing, so that the elastic blade 8 and the end portion are not manufactured. The seal member 10 could not be completely brought into close contact with each other, and a slight gap was sometimes formed between the two. as a result,
There is a problem that the developer 3 leaks as the developing sleeve 2 rotates.

Therefore, as shown in FIG. 10, the end portion of the end seal member 10 on the elastic blade 8 side is extended, and the extended portion is pushed from the back side of the elastic blade 8 (the side not contacting the developing sleeve surface). By applying the end seal member 10
A method has been proposed in which the is closely attached to the elastic blade 8.

[0006]

However, according to the above-mentioned conventional example, the portion of the elastic blade 8 pressed from the back side by the end seal member 10 has a higher contact pressure to the developing sleeve 2 than the other portions. Therefore, when used for a long period of time, an aggregate of the developer 3 may be formed in the portion. As a result, there is a problem in that the agglomerates are clogged in the contact portion between the elastic blade 8 and the developing sleeve 2, which hinders the formation of a thin layer of the developer on the developing sleeve 2.

The present invention solves the above-described problems, does not generate agglomerates of the developer, and is capable of reliably sealing even if there are variations in the manufacturing and mounting of the members. Is intended to provide.

[0008]

According to the present invention, the above-mentioned object is to contact a developer carrier rotatably disposed at an opening of a developer container and a surface of the developer carrier. An elastic blade disposed in such a manner, an end seal member that seals a gap in the opening formed between the elastic blade, the inner wall of the developer container, and the developer carrier, and the developer container. And a developer supply / separation unit that is disposed so as to rub against the surface of the developer carrier and supplies the developer to the developer carrier and separates the developer from the developer carrier. In the apparatus, the developer supply / detachment means supplies the developer to the non-image areas at both ends of the developer carrier that do not contribute to image formation in the area where the developer is supplied to the developer carrier. Among the above-mentioned developer carriers that contribute to image formation It is accomplished by being set to less than the image area parts.

[0009]

According to the present invention, the developer is supplied to the developer carrier by the developer supplying / peeling means, but the developer in the non-image areas at both ends of the developer carrier which does not contribute to image formation is It is supplied less than the intermediate image area.
Therefore, the amount of the developer around the non-image area or the end seal member arranged further on the end side than the non-image area is reduced, and the sealing is surely performed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First to fifth embodiments of the present invention will be described with reference to the drawings.

<First Embodiment> First, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. 1 and 2 are
FIG. 1 is a sectional view and a plan view of a first embodiment apparatus in which the present invention is applied to a dry non-magnetic one-component developing apparatus. In FIG. 1, reference numeral 1 is a hopper which is a developer container. A developing sleeve 2, which is a developer carrier, is rotatably supported in the opening of the hopper 1, and is rotationally driven in the direction of arrow B by a drive source (not shown). The developing sleeve 2 is made of a non-magnetic material such as aluminum or stainless steel, and carries the frictionally charged developer 3 which is a one-component non-magnetic developer in the hopper 1 on its surface by electrostatic attraction. ing.

Further, below the developing sleeve 2, a supplying / peeling roller 4 as a developer supplying / separating means is arranged so as to rotate by sliding at a sliding portion S. The supply / peeling roller 4 is made of an elastic material, and rotates in the same direction as the developing sleeve 2 so that the developer 3 is transferred to the developing sleeve 2.
The developer on the developing sleeve 2 is peeled off by being supplied to the developing sleeve 2 and making elastic contact with the developing sleeve 2. As shown in FIG. 2, the developer application region where the developer is supplied and peeled by the supply / peeling roller 4 is formed wider in the direction of both ends of the developing sleeve 2 than the image region, and is outside the image region. A scraper blade 5 as a developer stripping means for the supply / stripping roller 4 is disposed so as to abut on both ends of the supply / stripping roller 4 corresponding to the non-image area.

One end of the scraper blade 5 is attached to the support member 6, and the other end of the scraper blade 5 is abutted against the surface of the supply / peeling roller 4 at a contact portion U with the other end being a free end. The abutting portion U is located on the upstream side in the rotation direction of the supply / peeling roller 4 with respect to the rubbing portion S between the developing sleeve 2 and the supply / peeling roller 4, and on the supply / peeling roller 4. The developer 3 in the area corresponding to the non-image area is peeled off, and the developer 3 is dropped into the developer accommodating portion of the hopper 1.

A developer feeding member 7 is disposed in the developer accommodating portion behind the supply / peeling roller 4 for accommodating the developer 3 separated by the scraper blade 5 so as to rotate in the direction of arrow D. Then, the developer 3 is supplied to the supply / peeling roller 4. However, since the developer 3 on both ends is peeled off by the scraper blade 5,
On the supply / peeling roller 4, the developer 3 is held only in the area corresponding to the image area shown in FIG. 2, and the developer 3 hardly exists in the area corresponding to the non-image area.

On the other hand, the free end of the elastic blade 8 is in contact with the developing sleeve 2 on the downstream side in the rotational direction of the developing sleeve 2 with respect to the sliding portion S between the supplying / peeling roller 4 and the developing sleeve 2. It is arranged so as to abut at the section T,
At the contact portion T, the passage of the developer 3 on the developing sleeve 2 is regulated. As the elastic blade 8, it is preferable to use a material of frictional charging series suitable for charging the developer 3 to a desired polarity. For example, nylon, polyurethane, styrene butadiene, or the like may be used to negatively charge the developer containing polyester as a constituent component. By using the above materials, the triboelectrification efficiency of the developer can be further increased.

Below the developing sleeve 2, a seal member 9 for closing the gap between the developing sleeve 2 and the opening of the hopper 1 is arranged. The seal member 9 is formed of a flexible sheet such as Mylar (trade name of DuPont),
One end of the bent sleeve contacts the lower surface of the developing sleeve 2.

As described above, the end seal members 10 are arranged at both ends of the developing sleeve 2 with which the elastic blade 8 is in contact with the upper side and the seal member 9 is in contact with the lower side. Prevents leakage. The end seal member 1
Reference numeral 0 denotes an elastic member, which is slidably contacted in the circumferential direction with the surface of the developing sleeve 2 projecting into the hopper 1. The end seal member 10 is the developing sleeve 2
Of the side end face of the end seal member 10 at the boundary position with the developer application region as in the conventional example shown in FIG. The elastic blade 8 and the side end surface of the seal member 9 are in contact with each other.

In the developing device as described above, when the developer feeding member 7 shown in FIG. 1 is rotated in the direction of arrow D to convey the developer 3 to the supply / peeling roller 4 side, the developer 3 is supplied / supplied. The peeling roller 4 is carried over the entire area of the supply / peeling roller 4 in the longitudinal direction. The carried developer 3 is conveyed to the rubbing portion S with the developing sleeve 2 by the rotation of the supply / peeling roller 4 in the direction of the arrow C. At this time, the developer 3 was carried by the supply / peeling roller 4. The developer 3 carried on the non-image area is peeled off at the contact portion U of the scraper blade 5. Therefore, in the rubbing portion S, the developer 3 is supplied only to the image area and is not supplied to the non-image area.

The developer 3 in the image area which has been frictionally charged by being slid on the developing sleeve 2 at the sliding portion S is moved to the contact portion T of the elastic blade 8 by the rotation of the developing sleeve 2 in the direction of arrow B. While being conveyed, when it passes through the contact portion T between the elastic blade 8 and the developing sleeve 2, the surface of the developing sleeve 2 is rubbed by the elastic blade 8 and further frictionally charged. In this way, the developer 3 can receive sufficient triboelectrification.

The developer 3 which has received the sufficient frictional charge passes through the abutting portion T and is formed as a thin developer layer on the developing sleeve 2, and the developing sleeve 2 serves as a photosensitive drum (not shown). It is transported to the opposite developing section. In addition, the contact portion T
As described above, most of the developer 3 that passes through is present in the image area and very little is present in the non-image area.
Therefore, the amount of the developer around the end seal member 10 is also reduced, so that the sealing operation is reliably performed.

On the other hand, in the developing section, a part of the developer is consumed by the developing operation, and the other developer is collected from the lower part of the developing sleeve 2 as the developing sleeve 2 rotates. A seal member 9 is provided in this collecting portion to allow passage of the developer not consumed in the development into the hopper 1, and
The developer 3 in the hopper 1 is prevented from leaking from the lower part of the hopper 1. The collected developer on the developing sleeve 2 is rubbed by the supplying / peeling roller 4 and the developing sleeve 2.
It is scraped off by elastic contact. The developer 3 scraped off merges with the developer 3 carried by the toner feeding member 7, and is carried to the rubbing portion S again as described above.

As described above, according to the apparatus of this embodiment, the area where the developer 3 is present on the developing sleeve 2 is limited to the image area, and the developer around the end seal member 10 can be significantly reduced. Even if the conventional sealing method shown in FIG. 9 is used, a reliable sealing operation can be realized without adversely affecting the image. Therefore, it is possible to stably form a thin layer of the developer by the elastic blade 8 without generating an aggregate of the developer as in the conventional case. Further, even if there are some variations in the manufacturing or mounting of the members, as described above, the developer around the end seal member 10 is extremely small, so that the sealing operation can be surely performed.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

FIG. 3 is a sectional view showing a schematic structure of this embodiment,
FIG. 4 is a plan view thereof. This embodiment differs from the first embodiment in that a scraper roller 11 is used instead of the scraper blade 5 as shown in FIGS. 3 and 4.

With the scraper blade, as the endurance of the scraper was increased, the blade edge was chipped or the developer was fused at the edge portion, resulting in scraping failure. However, according to the present embodiment, it is possible to always stably scrape the developer in the area corresponding to the non-image area on the supply / peel roller 4 without causing scraping failure even during long-term use. it can. As a result, a high sealing effect can be maintained.

<Third Embodiment> Next, a third embodiment of the present invention will be described with reference to FIG. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, as shown in FIG. 5, the scraper blade 5 is not provided, and the outer diameters of both ends of the feeding / peeling roller 4 corresponding to the non-image area are set to the central portion corresponding to the image area. The difference from the first embodiment is that the outer diameter is smaller than the outer diameter.

The amount of developer applied to the developing sleeve 2 depends on the pressure between the developing sleeve 2 and the supply / peeling roller 4 and the nip width, so that it corresponds to the non-image area as in this embodiment. If the outer diameter of the area to be filled is reduced, the pressure and the nip width are reduced, and the amount of developer applied to the non-image area can be reduced. Therefore, the amount of the developer around the end seal member can be reduced and a reliable sealing operation can be realized.

<Fourth Embodiment> Next, a fourth embodiment of the present invention will be described with reference to FIG. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the present embodiment, as shown in FIG. 6, the processing of the material itself or its surface at both end portions corresponding to the non-image area of the supply / peeling roller 4 is different from that at the central portion corresponding to the image area. This is different from the first embodiment. In addition, the scraper blade 5 is used as in the third embodiment.
Is not provided.

For example, when a foam is used for the supply / peeling roller 4, the number of bubble portions per unit volume (hereinafter referred to as the number of cells) at both ends is smaller than that at the central portion. As a result, the amount of developer supplied to the developing sleeve 2 is smaller than that in the central portion where the number of cells per unit volume is large, so that the amount of developer around the end seal member 10 is reduced and the first embodiment is performed. Produces the same effect as. Further, the developer is rubbed between the developing sleeve 2 and the supply / peeling roller 4 to be triboelectrically charged, and is applied to the developing sleeve 2 by electrostatic attraction. May be made of a material that gives a small amount of charge to the developer by frictional charging. Furthermore, the surface of the foamed material at both ends may be melted by heat to reduce the developer coating performance.

<Fifth Embodiment> Next, a fifth embodiment of the present invention will be described with reference to FIG. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, as shown in FIG. 7, both ends of the supply / peeling roller 4 corresponding to the non-image area are connected to the shaft 1.
It is different from the first embodiment in that it is configured as a separate member 13 rotatable around 2. The member 13 is a bearing portion 14 on the inner circumference.
And the outer peripheral foam body 15.

The central portion of the supply / peeling roller 4 corresponding to the image area is rotated by the shaft 12 in the counter direction which is the same direction as the rotation direction of the developing sleeve 2, but the member 13 contacts the developing sleeve 2. It rotates driven by contact. Therefore, the developer supply amount to the non-image area of the developing sleeve 2 is reduced without frictionally charging or rubbing the developer, so that the developer amount around the end seal member 10 is reduced and a reliable seal is obtained. You can take action.

[0035]

As described above, according to the present invention,
The developer supply / separation means is set so that the supply of the developer to the non-image areas at both ends of the developer carrier that does not contribute to image formation is set to be smaller than that in the image area at the intermediate portion. The amount of developer around the seal member decreases, and a reliable sealing operation can be performed even with a simple structure in which the end face of the end seal member is brought into close contact with the end faces of the surrounding members. Does not occur. Also,
Even if there is some variation in manufacturing or mounting of the members, the sealing effect can be sufficiently exerted.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic configuration of a first embodiment device of the present invention.

FIG. 2 is a plan view of the device of FIG.

FIG. 3 is a cross-sectional view showing a schematic configuration of a second embodiment device of the present invention.

FIG. 4 is a plan view of the device of FIG.

5A and 5B are a plan view and a front view of a developer supply / separation unit according to a third embodiment of the invention.

6A and 6B are a plan view and a front view of a developer supply / separation unit according to a fourth embodiment of the present invention.

FIG. 7 is a plan view and a perspective view of a developer supply / separation unit according to a fifth embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a schematic configuration of a conventional device.

FIG. 9 is a cross-sectional view for explaining a sealing method in a conventional device.

FIG. 10 is a cross-sectional view for explaining another sealing method in the conventional device.

[Explanation of symbols]

1 Developer container (hopper) 2 Developer support (development sleeve) 3 developer 4 Developer supply peeling means (supply / peeling roller) 8 elastic blades 10 End seal member

Claims (5)

[Claims] 1. A developer carrying member rotatably arranged at an opening of a developer container, an elastic blade arranged so as to abut a surface of the developer carrying member, and the elastic blade, An end seal member that seals a gap in the opening formed between the inner wall of the developer container and the developer carrier, and so as to rub against the surface of the developer carrier in the developer container. In a developing device, which is provided with a developer supply / peel means for supplying the developer to the developer carrier and for peeling the developer from the developer carrier, the developer supply / peel means is the developer. Among the regions for supplying the developer to the carrier, the developer is supplied to the non-image regions at both ends of the developer carrier which do not contribute to image formation, and the intermediate part of the developer carrier that contributes to image formation. Is set to be less than the image area of Developing device. 2. The developer peeling means is disposed so as to abut on both end surfaces of the developer supply peeling means that slides against the non-image area of the developer carrying member. Developing device. 3. The developing device according to claim 1, wherein the outer diameters of both ends of the developer supplying / separating means that rubs against the non-image area of the developer carrying member are smaller than the intermediate portion. 4. The developer supply / peel means for rubbing against the non-image area of the developer carrier is formed with a member different from the intermediate part, or different from the intermediate part on the surface or on the whole. 2. The developing device according to claim 1, wherein the developer holding amount at the both end portions is set to be smaller than that at the intermediate portion by being formed of a member subjected to the above treatment. 5. The developer supply / peel means for rubbing against the non-image area of the developer carrier is constituted so that both ends thereof are driven to rotate independently of the intermediate part.
The developing device according to 1.