JPH10207215A - Developing device and image forming device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of history phenomenon caused by the remaining of an unused developer on a developer carrier while preventing the degradation of toner carrying function and the increase of rotational driving load by providing a mesh-like peeling member having an opening in such a degree that clogging with the unused developer peeled from the developer carrier does not occur. SOLUTION: A developer supplying member 3 is provided with an elastic layer 3a, a skin layer 3b and a mesh-like peeling layer 3c. The developer supplying member 3 carries out the developer to the developer carrier 2, in accordance with a rotary motion. At this time, the infiltration of the developer into the elastic layer 3a is prevented by the skin layer 3b covering the outside surface of the developer supplying member 3. Further, the developer on the developer carrier 2, not used for development is led to the gap between the developer carrier 2 and the mesh-like peeling member 4, in accordance with the rotation of the developer carrier 2. At this time, the unused developer is peeled from the developer carrier 2 by the mesh-like peeling member 4 through the use of the ruggedness of its surface, while the developer peeled by opening structure is led to the side of the developer supplying member 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic copying machine,
In an image forming apparatus such as a laser printer, the present invention relates to a developing device that develops an electrostatic latent image formed on a latent image carrier,
In particular, the present invention relates to a developing device using a non-magnetic one-component developer and an improvement of an image forming apparatus using the developing device.

[0002]

2. Description of the Related Art In recent years, as miniaturization and simplification of electrophotographic copying machines, laser beam printers, and the like have progressed, a one-component development system has attracted attention as a development system for visualizing an electrostatic latent image. Particularly in recent years, colorization has been advanced, and many studies have been made on a non-magnetic one-component developing method using no magnetic toner. Conventionally, as this type of developing method, a non-magnetic one-component developing method in which a thin layer of non-magnetic one-component toner is formed on a developing roll and the electrostatic latent image formed on the photoreceptor is visualized by the developing roll is used. Known (JP-A-47-130)
88, JP-A-53-167341).
This non-magnetic one-component development method is a one-component toner and does not require a carrier, so there is no problem such as carrier deterioration or carrier adhesion.Because the toner is non-magnetic, it does not contain magnetic powder and has clear color. It has the feature that development is possible. The developing device generally includes a housing that is opened to face a photoconductor that carries an electrostatic latent image and stores toner, a developing roll that is disposed facing the opening of the housing and carries the toner, A layer thickness regulating member in the vicinity of the opening and in contact with the developing roll and in which the toner is thinned and frictionally charged on the developing roll, and the toner which is disposed in the housing at the back of the developing roll and pressed against the developing roll. Is provided with a supply roll transported to the developing roll, and a toner stirring member disposed behind the supply roll in the housing and agitating and transporting the toner. Here, the supply roll not only transports new toner to the development roll, but also
Since it also has the function of mechanically and electrically peeling off unused toner on the developing roll, it is generally formed of a porous elastic material such as urethane foam or sponge having an uneven surface.

[0003]

However, when the porous elastic material is used for the supply roll, the toner penetrates into the foamed pores and gradually penetrates into the center of the roll with use, and the clogging proceeds. Occurs. As a result, the supply roll itself loses its elasticity, and the function of collecting unused toner on the development roll and the function of transporting new toner are reduced, and the rotational drive load is further increased, resulting in lack of durability and reliability. There was a technical challenge.

On the other hand, at the same time that the toner is conveyed to the developing roll in a uniform distribution by the supply roll, the outer surface of the porous elastic body used for the supply roll is used so as not to increase the rotational driving load of the supply roll. There is also known a technique of providing a synthetic resin layer on a substrate (see JP-A-62-269977). However, according to this technical means, although it is possible to prevent clogging due to penetration of the toner into the elastic body, since the surface of the developing roll is smoothed by the synthetic resin layer, the unused toner on the developing roll is Cannot be sufficiently removed. For this reason, there is a technical problem that a history phenomenon occurs when unused toner not used for development remains on the developing roll.

Accordingly, the present invention has been made to solve the above technical problems, and it is possible to prevent a decrease in the developer transport function and an increase in the rotational driving load, and to further develop an unused developer. It is an object of the present invention to provide a developing device which prevents a hysteresis phenomenon due to a residual on a developer carrier and improves image quality, and an image forming apparatus using the same.

[0006]

That is, according to the present invention, as shown in FIG. 1, a developer carrier 2 carrying a developer for visualizing a latent image on a latent image carrier 1 is provided. In a developing device provided with a developer supply member 3 for supplying the developer to the developer carrier 2, the developer supply member 3 circumscribes the elastic layer 3a holding the developer and the elastic layer 3a, A skin layer 3b for preventing penetration into the elastic layer 3a, and further sandwiched between the developer carrier 2 and the developer supply member 3 to remove unused developer on the developer carrier 2; It is provided with a mesh-shaped peeling member 4 having an opening that is not clogged with the peeled developer.

In the means for solving the above problems, the size of the opening of the mesh-like peeling member 4 is set so that if the mesh is too small, the peeling function is reduced due to clogging of the toner in the opening. From the viewpoint of having a lower limit,
Further, if the mesh size is too large, the contact area is reduced and the toner is not uniformly peeled, and thus has an upper limit.

From the viewpoint of simplifying the configuration of the device,
A developing device including a developer carrier 2 for carrying a developer for visualizing a latent image on the latent image carrier 1 and a developer supply member 3 for supplying the developer to the developer carrier 2 In the apparatus, the developer supply member 3 includes an elastic layer 3a that holds the developer, a skin layer 3b that circumscribes the elastic layer 3a and prevents the developer from entering the elastic layer 3a, Release layer 3 from which unused developer on agent carrier 2 is released
It is preferable to have c.

Further, from the viewpoint of obtaining a high quality image, it is preferable to apply the present invention to an image forming apparatus.

The operation of the present invention will be described below. The developer supply member 3 conveys the developer to the developer carrier 2 with the rotational movement. At this time, the skin layer 3b covering the outer surface of the developer supply member 3 prevents the developer from entering the elastic layer 3a. In addition, the developer on the developer carrier 2 that has not been used for development is guided between the developer carrier 2 and the mesh-shaped peeling member 4 as the developer carrier 2 rotates. At this time, the mesh-shaped peeling member 4 peels the unused developer from the developer carrier 2 due to the unevenness of the surface, and guides the peeled developer by the opening structure to the developer supply member 3 side.

[0011]

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 first embodiment in which the present invention is applied to an image forming apparatus.
It shows. In this embodiment, reference numeral 21 denotes a photosensitive member that carries a latent image, 22 denotes a charging device such as a corotron that charges the photosensitive member 21, and 23 denotes a latent image written on the photosensitive member 21, for example, a semiconductor laser, a polygon rotating mirror. , A developing device for visualizing a latent image formed on the photoconductor 21, a transfer device 25 for transferring a toner image on the photoconductor 21 to a recording paper P, and a recording device 26. A fixing device 27 to which the toner image on the sheet P is thermally fused is a cleaning device 27 for removing residual toner on the photoconductor 21. Reference numeral 28 denotes a registration roll for adjusting the position of the recording paper, and 29 denotes a transport belt for transporting the recording paper P.

FIG. 3 shows a developing device 2 according to the first embodiment.
4 is enlarged. The main developing device 24 includes the photoconductor 2
241 which is open to face and accommodates toner
A developing roll 242 arranged facing the opening of the housing 241, a layer thickness regulating member 243 arranged in contact with the developing roll 242 near the opening of the housing 241,
A supply roll 244 that is arranged in contact with the inside of the housing 241 on the inner side of the developing roll 242,
It is composed of a stirring member 245 disposed inside and behind the supply roll 244, and a mesh member 246 sandwiched between the development roll 242 and the supply roll 244.

FIG. 4 shows a developing roll 242, a supply roll 244, a layer thickness regulating member 243, and a mesh material 246 according to the present embodiment. The developing roller 242 has a cylindrical shape, and may be made of aluminum, iron, or stainless steel, and may have a surface roughness Ra of about 0.2 to 2.0 μm. In this embodiment, for example, an aluminum round bar having a diameter of 20 mmφ is machined on the circumferential surface to form irregularities with a surface roughness Ra of about 1.0 μm. The aluminum roll may be mechanically polished and then subjected to anodizing treatment before use.

The supply roll 244 includes a shaft 244a that supports the supply roll 244, an elastic layer 244b that circumscribes the shaft 244a, and a skin layer 244c that covers the outer surface of the elastic layer 244b. Here, shaft 2
Reference numeral 44a is made of a metal having a certain strength. In the present embodiment, for example, a stainless steel shaft having a diameter of 16 mmφ is used. The elastic layer 244b is a cylindrical foamed resin layer, and its material is, for example, urethane foam type,
Alternatively, a silicon-based material may be used and the electric resistance value is 10 ³ to 10
^A hardness of about ¹⁰ Ωcm and a hardness of about 10 degrees Aska C hardness may be used. In the present embodiment, for example, a urethane-based foamed resin layer having an electric resistance of about 10 ⁶ Ωcm and a hardness of about 10 degrees Aska C hardness is used. . The skin layer 244c is in the form of a thin sheet, and is made of, for example, polyethylene terephthalate, polyethylene, polypropylene, or polyamide.

The layer thickness regulating member 243 is formed by bonding a rubber material to a leaf spring material. The leaf spring material may be a stainless or copper-based elastic material. In this embodiment, for example, a material in which a urethane rubber material is bonded to a copper leaf spring material is used.

The mesh material 246 is formed as shown in FIG.
It has a mesh shape (plain weave, twill weave, satin fold), and has an appropriate pressing force (50 between the developing roll 242 and the supply roll 244).
g / cm), and both ends of the mesh material 246 in the axial direction of the developing roll 242 are fixed to the housing 241. The pressing force at that time is determined by the hardness of the elastic layer 244b of the supply roll 244. The material may be a polyamide resin, another synthetic resin, or glass fiber. In this embodiment, for example, a polyamide resin is used. The hardness of the mesh material 246 is the same as that of the developing roll 2.
It does not deform even by the pressing force of the supply roll 242 and the supply roll 244, and does not deform by friction between the developing roll 242.

Further, based on FIG.
The relationship between the opening area of No. 6 and the hysteresis phenomenon will be described. In the figure, the degree of the hysteresis is evaluated in five steps, the degree when the mesh material 246 is not used is set to 5, and when no hysteresis is observed, it is set to 0. The average particle size of the toner used for the measurement is 10 μm. According to this, the degree of the hysteresis phenomenon decreases as the opening area of the mesh material 246 increases, and does not occur at 70 ² μm ² . However, when the opening area exceeds 350 ² μm ² , the hysteresis occurs again, and as the opening area increases, the degree of the hysteresis deteriorates. The diameter of a circle having the same area as the opening area of 70 ² μm ² is about 80 μm, and the diameter of the circle having the same area as the opening area of 350 ² μm ² is about 400 μm. From the above results, it is possible to efficiently remove the unused toner from the developing roll 242,
The mesh opening area of the mesh material 246 where good development is performed without occurrence of a hysteresis phenomenon is 8 to 8 times the average toner particle diameter.
It is understood that it is 40 times.

Next, the developing device 24 according to the present embodiment
Will be described. The toner contained in the housing 241 is stirred by the stirring member 245 and is conveyed to the supply roll 244 side. Supply roll 24
4 rotates at a predetermined speed while pressing against the mesh material 246 sandwiched between the developing roll 242 and the supply roll 244,
The toner is transported to the developing roll 242. At this time, the skin layer 244c provided on the outer surface of the supply roll 244 prevents the toner from entering the inside of the elastic layer 244b. The toner held on the surface of the developing roll 242 is
The layer thickness regulating member 243 forms a uniform toner layer having a predetermined thickness, and applies a charge necessary for development to the toner by frictional charging. The frictionally charged toner is conveyed to a portion facing the photoreceptor 21 and the photoreceptor 2
The electrostatic latent image is developed by an alternating electric field formed between the developing roller 1 and the developing roll 242. On the other hand, the toner remaining on the developing roller 242 without being used for development is guided between the developing roller 242 and the mesh material 246 as the developing roller 242 rotates. At this time, the unevenness on the surface of the mesh material 246 catches the residual toner, and peels off the residual toner from the developing roll 242. The peeled toner stays in the opening of the mesh material, is subsequently pushed out to the supply roll 244 side by the peeled toner, and is collected in the housing 241. As described above, according to the present embodiment, the supply roll 2
The hysteresis phenomenon is prevented while preventing a decrease in the toner conveyance capacity of 44 and an increase in the rotational driving load.

Second Embodiment FIGS. 7 and 8 show a second embodiment. The present embodiment has substantially the same configuration as that of the first embodiment, but does not use the mesh material 246 and uses the skin layer 24 of the supply roll 244.
4c is characterized in that a mesh layer 244d formed on the outer peripheral surface is provided. Here, the skin layer 244c has, for example, an outer surface of the elastic layer 244b adhered to a heat-shrinkable thin film sheet, and then heat is applied to cause heat shrinkage, and the skin is fixed to the elastic layer 244b by tension generated in the entire sheet. It is formed by this. The mesh layer 244d is formed, for example, by winding a flat mesh sheet around the outer peripheral surface of the skin layer 244c, butting one end and the other end, and fixing the one end to the skin layer 244c with an adhesive. You. Next, the operation of the developing device according to the present embodiment will be described. Toner scraped off from the developing roll 242 due to unevenness on the surface of the mesh layer 244d stays in the concave portion on the surface of the mesh layer 244d, and is supplied to the supply roll 244.
When the staying portion of the toner faces the lower surface of the housing 241 due to the rotation of the
41, is removed from the concave portion of the mesh layer 244d by being rubbed with the stored toner in the housing 41, and is collected in the housing 241. According to this, the same effects as those of the first embodiment can be obtained, and the device configuration can be simplified.

Comparative Embodiment This comparative embodiment has substantially the same configuration as that of the second embodiment except that the surface of the elastic layer 244b of the supply roll 244 is provided with irregularities, and the surface of the elastic layer 244b is further provided with a skin layer. 244c
It is different in that it is covered with. According to this, the elastic layer 244b
Although the clogging was prevented, it was confirmed that the peeling performance of the unused toner on the developing roll 242 was insufficient.

[0021]

According to the present invention, the developer is prevented from entering the elastic layer by the skin layer, and the unused developer on the developer carrier is peeled off by the mesh-like peeling member. A hysteresis phenomenon is prevented while preventing a decrease in the developer carrying capacity of the developer supply member and an increase in the rotational driving load. Further, by providing a mesh layer on the outer peripheral surface of the skin layer, the configuration of the device can be simplified.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a conceptual diagram of the present invention.

FIG. 2 is an explanatory diagram showing a first embodiment in which the present invention is applied to an image forming apparatus.

FIG. 3 is an explanatory diagram showing an enlargement of a developing device according to FIG. 2;

FIG. 4 is an explanatory view showing a structure of a supply roll and the like according to FIG. 2;

FIG. 5 is an explanatory diagram showing an enlargement of a mesh material according to FIG. 2;

FIG. 6 is an explanatory diagram showing a relationship between an opening area of a mesh material and a hysteresis phenomenon according to FIG. 2;

FIG. 7 is an explanatory diagram showing a main part according to the second embodiment.

FIG. 8 is an explanatory view in a perspective direction of a supply roll according to FIG. 7;

DESCRIPTION OF SYMBOLS 1 ... Latent image carrier, 2 ... Developer carrier, 3 ... Developer supply member, 4 ... Mesh release member, 3a ... Elastic layer, 3b ... Skin layer, 3c ... Mesh release layer

 ──────────────────────────────────────────────────続 き Continued from the front page (72) Inventor Teruaki Koizumi 2274 Hongo, Ebina-shi, Kanagawa Fuji Xerox Co., Ltd.

Claims (3)

[Claims] A developer carrier (2) for carrying a developer for visualizing a latent image on a latent image carrier (1), and a developer is supplied to the developer carrier (2). Developer supply member (3)
The developer supply member (3) includes an elastic layer (3) on which the developer is held.
a) and an elastic layer (3a) of a developer circumscribing the elastic layer (3a)
And a skin layer (3b) for preventing intrusion into the developer carrier. Further, the skin layer (3b) is sandwiched between the developer carrier (2) and the developer supply member (3), and the unused developer on the developer carrier (2) is A developing device characterized by comprising a mesh-like peeling member (4) having an opening to such an extent that the agent is peeled off and is not clogged with the peeled developer. 2. A developer carrier (2) for carrying a developer for visualizing a latent image on a latent image carrier (1), and a developer is supplied to the developer carrier (2). Developer supply member (3)
The developer supply member (3) includes an elastic layer (3) on which the developer is held.
a) and the elastic layer (3a) of the developer circumscribing the elastic layer (3a).
a) a skin layer (3b) for preventing intrusion into a); and a mesh release layer (3c) circumscribing the skin layer (3b) and releasing unused developer on the developer carrier (2). A developing device characterized in that: 3. An image forming apparatus comprising: the image forming apparatus according to claim 1;