JPH0527577A - Development device - Google Patents

Abstract

(57) [Summary] [Objective] The one-component non-magnetic developer carried on the developer carrier is well regulated by a regulating member so that the developer is provided with sufficient triboelectric charge and at the same time on the developer carrier. (EN) Provided is a developing device capable of stably providing a high-quality image having uniform density and no fog by developing by applying a uniform thin layer. [Structure] Both ends of the elastic blade 4 along the rotation direction of the developing sleeve 3 are supported by a support holder 42 attached to the developing container 2, and the central portion excluding both ends of the blade 4 is elastically supported by the sleeve 3. Abutted. [Effect] Since the contact portion T of the blade 4 with the sleeve 3 can be formed in a large area, a sufficient triboelectric charge is given to the one-component non-magnetic developer 7 carried on the sleeve 3, and the sleeve 3 is also provided with It can be applied in a uniform thin layer, and a desired image can be obtained by development.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used for developing and visualizing a latent image formed on an image bearing member in image formation using an electrophotographic system or the like, and particularly to a one-component developer. The present invention relates to a developing device that develops by using.

[0002]

2. Description of the Related Art In an image forming apparatus utilizing an electrophotographic method, a latent image formed on an image carrier is developed by a developing device to be visualized as a toner image. A developing device that uses a dry one-component developer is known.

Conventionally, various developing devices using a one-component developer (toner) have been proposed and put into practical use. As a mechanism for imparting a triboelectric charge to a one-component developer, a triboelectric charging between developers or a triboelectric charging between a developer and a developer carrier has been proposed.
Regardless of which mechanism is adopted, it is desirable to form the developer in a thin layer on the surface of the developer carrier for imparting triboelectric charge. However, it is difficult to form a thin layer of the developer on the surface of the developer carrier, and many developing devices stop forming a relatively thick developer layer.

As a conventionally known method for forming a thin layer of a one-component developer, for example, JP-A-54-43037 has been proposed and put into practical use. However, this relates to the formation of a thin layer of a magnetic developer in which magnetic particles are internally added, and not the formation of a thin layer of a non-magnetic developer. Magnetic developers have problems that they have poor heat fixing properties on transfer paper and that they are poor in color reproducibility when used as color developers.

As a method for forming a thin layer of a one-component non-magnetic developer, a soft fiber such as a beaver hair is made into a cylindrical fiber brush, which is used as a developer carrying member, and the developer is further formed thereon. Has been proposed, and a method of applying it by a doctor blade or the like on a developer carrying member whose surface is made of fibers such as velvet has been proposed.

However, in these methods, it is difficult to apply the developer uniformly, or the triboelectric charge is insufficiently applied to the developer, so that uneven image density and fogging are likely to occur. There is a problem.

As shown in FIG. 5, one-component non-magnetic developer 7
Developing sleeve 3 installed in a developing container 2 containing
A rubber plate on which the developer 7 is supplied and carried by the developer supply roller 5 made of an elastic roller brought into contact with the developer, and the carried developer 7 is elastically brought into contact with the developing sleeve 3. A method of forming a thin layer of the developer 7 on the developing sleeve 3 by regulating the elastic blade 4 made of a metal plate or the like has been proposed and put into practical use in Japanese Patent Publication No. 63-16736.

In such a method for forming a thin developer layer, the elastic blade 4 is developed by applying the triboelectric charge to the developer 7 and forming a uniform thin developer layer by the triboelectrically charged developer 7. It is determined by the contact state with the sleeve 3. In this case, the developer 7 is triboelectrically charged by the contact with the elastic blade 4 and the developing sleeve 3 and is given an electric charge. Therefore, if the contact pressure of the elastic blade 4 with the developing sleeve 3 is increased, the charge can be sufficiently applied to the developer 7.

[0009]

However, when the contact pressure of the elastic blade 4 with the developing sleeve 3 is increased, excessive pressure is applied to the developer 7 at the contact portion, and the developing sleeve 3
The fusion of the developer 7 onto the surface of the developer 7 causes uneven coating. Therefore, even if both the formation of a uniform thin developer layer on the developing sleeve 3 and the provision of sufficient triboelectric charge of the developer 7 due to the restriction of the elastic blade 4 are opposed to each other. It was difficult to realize together.

Therefore, in view of the above situation, an object of the present invention is to provide a one-component non-magnetic developer carried on a developer carrier by a developer regulating member elastically abutted on the developer carrier. It is possible to form a uniform thin layer of the developer on the developer carrier and to give sufficient triboelectrification charge to the developer, so that the density is uniform and no fog is produced by the development. It is an object of the present invention to provide a developing device capable of stably obtaining an image.

[0011]

The above object can be achieved by the developing device according to the present invention. In summary, the present invention regulates a one-component non-magnetic developer carried on a developer carrier by a developer regulating member elastically abutting the developer carrier, and In a developing device that conveys the developer to a developing unit facing the image carrier by rotating the developer carrier while forming a thin layer of the developer on the developing device, In the developing device, the supporting member is elastically contacted with the developer carrying member at a portion between the supporting members by supporting the restricting member at two positions spaced along the rotation direction. is there. Preferably, the developer is carried on the developer carrier by being supplied by a supply roller that elastically abuts on the developer carrier.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view showing an embodiment of the developing device of the present invention. As shown in FIG. 1, the main developing device is provided so as to face the photosensitive drum 1 of the image carrier that rotates in the arrow A direction. The photosensitive drum 1 is composed of a photosensitive member having an organic photoconductive layer provided on a conductive substrate, and an electrostatic latent image is formed on the surface of the photosensitive drum by an electrostatic recording unit (not shown).

The developing device includes a developing container 2 accommodating a one-component non-magnetic developer (non-magnetic toner) 7, a developing sleeve 3 of a developer carrier installed in the developing container 2, and a developer regulating means. The elastic blade 4, the supply roller 5 of the developer supplying means, and the feeding member 6 of the developer conveying means are provided.

The developing container 2 has an opening extending in the longitudinal direction at right angles to the paper surface at a position facing the photosensitive drum 1, and the developing sleeve 3 is rotatably disposed in this opening. . The developing sleeve 3 is rotationally driven in the direction of arrow B by a drive source (not shown). On the surface of the developing sleeve 3,
In order to ensure the retention of the developer, unevenness having a pitch of 0.5 to 5 μm is formed.

The supply roller 5 is disposed behind the developing sleeve 3 on the side opposite to the photosensitive drum 1 side, and is rotatably installed so as to elastically contact the developing sleeve 3 at the contact portion S. The supply roller 5 is in elastic contact with the developing sleeve 3 to peel off the undeveloped developer on the developing sleeve 3 and supply the developer 7 in the developing container 2 onto the developing sleeve 3 to carry it. It is for making it.

The elastic blade 4 is provided at a position downstream of the contact portion S of the developing sleeve 3 in the rotational direction. Now, in the present invention, the elastic blade 4 is fixed and supported at two positions spaced apart along the rotation direction of the developing sleeve 3 of the elastic blade 4 directly or on the support holder 42 attached to the developing container 2. Is arranged so as to abut the developing sleeve 3 at a portion between the supported portions. In this embodiment, as shown in FIG. 2, the developing container 2 is provided with a support holder 42 formed of a frame body having a substantially U-shaped cross section having two support pieces 42a and 42b which face each other. By fixing both ends of the elastic blade 4 to the supporting pieces 42a and 42b so as to support the elastic blade 4, the elastic sleeve 4 is brought into contact with the developing sleeve 3 at the central portion excluding both ends.

The contact portion T formed by the contact of the elastic blade 4 with the developing sleeve 3 is long in the rotation direction of the developing sleeve 3 and has a large area. Therefore, according to the present invention, the developing sleeve 3 of the elastic blade 4 is
The developer 7 having the contact portion T with the developing sleeve 3 carried on the developing sleeve 3.
While the toner passes through, the developer 7 can be well regulated to give a sufficient triboelectric charge, and can be applied on the developing sleeve 3 in a uniform thin layer. Therefore, a high-quality image having uniform density and no fog can be stably obtained by the development.

As the elastic blade 4, polyisoprene, butadiene-styrene copolymer, polybutadiene,
Isobutylene-isoprene copolymer, butadiene-acrylonitrile copolymer, ethylene-propylene copolymer, chlorosulfonated polyethylene, acrylic ester copolymer, polyurethane, organic polysiloxane, perfluoropropene, vinylidene fluoride copolymer, etc. Rubber elastic members, single layers of elastic metal members such as Ni, SUS, Al, phosphor bronze, etc., or polyamide, polyimide, polyamide imide, polyether imide, polyether ether ketone, polyphenylene sulfide, liquid crystal polymer, etc. It is composed of laminated composite layers.

As the rubber elastic member used for the elastic blade 4, specifically, it is preferable to select a frictional charging series member suitable for charging the developer 7 to a desired polarity.
For example, in order to negatively charge a developer containing polyester as a resin component, it is preferable to use a material obtained by laminating polyamide on urethane rubber for the elastic blade 4. If a conductive rubber in which metal particles and the like are dispersed is also used for the elastic blade 4, it may be effective against aggregation and solidification of the developer 7 due to excessive triboelectric charging.

The developer feeding member 6 is rotatably installed in a portion inside the developing container 2 behind the supply roller 5 and rotates in the direction of arrow D to supply the one-component non-magnetic developer 7 in the developing container 2. It is designed to be conveyed to the roller 5. Supply roller 5
A barrier 8 having an open central portion is provided between the feeding member 6 and the feeding member 6. The barrier wall 8 prevents the developer 7 from being excessively conveyed to the supply roller 5 by the feeding member 7, and also causes the developer 7 sent to the supply roller 5 to be developed by the supply roller 5.
It is designed to merge with the developer that has been peeled off. The combined developer is carried on the supply roller 5 and conveyed again to the contact portion S with the developing sleeve 3.

Below the developing sleeve 3, there is provided a sealing member 9 for closing a gap with the developing container 2. Further, a bias power source 10 for applying a developing bias is provided between the photosensitive drum 1 and the developing sleeve 3, and the developing sleeve 3
The developer 7 on the supply roller 5 is located between the supply roller 5 and the supply roller 5.
A bias power supply 11 for applying a bias for adhesion to the photosensitive drum 1 is provided.

The developer 7 formed in a thin layer on the developing sleeve 3 is conveyed to the developing section facing the photosensitive drum 1 by the rotation of the developing sleeve 3, and the electrostatic latent layer formed on the photosensitive drum 1 there. The image is electrostatically transferred to visualize the electrostatic latent image as a toner image. The toner image thus formed on the photosensitive drum 1 is transferred onto a recording material such as paper at a transfer portion of the image forming apparatus, and then the recording material is fixed on the recording material and then transferred outside the image forming apparatus. Is discharged to.

As the developing method of the developing device of this embodiment,
For example, the method described in JP-B-58-32375, that is, an alternating voltage in which a DC voltage is superimposed between the photosensitive drum 1 and the developing sleeve 3 is applied as a developing bias to expose the developer layer formed on the developing sleeve 3 to light. A so-called non-contact developing method of transferring to the electrostatic latent image on the drum 1 can be used,
Alternatively, a contact development method may be used.

A resin layer containing conductive particles may be applied and formed on the surface of the developing sleeve 3. By reducing the resistance value on the surface of the developing sleeve 3,
In order to prevent the accumulation of electric charges on the surface and to improve the developability in non-contact development, it is preferable to keep the volume resistivity of the surface of the developing sleeve 3 at 10 ⁴ Ωcm or less. It is preferable that the resin used has a high ability to impart a triboelectric charge to the developer 7, and therefore it is preferable to use a resin having a triboelectric charge series different from that of the developer 7. For example, as used in the elastic blade 4, polyisoprene, butadiene-styrene copolymer, polybutadiene, isobutylene-isoprene copolymer, butadiene-acrylonitrile copolymer, ethylene-propylene copolymer, chlorosulfonated polyethylene, acrylic acid. Ester copolymer, polyurethane, organic polysiloxane, perfluoropropene, vinylidene fluoride copolymer, polyamide, polyimide, polyamideimide, polyetherimide, polyetheretherketone, polyphenylene sulfide, liquid crystal polymer and the like are preferable. These are appropriately selected depending on the polarity of the triboelectric charge to be imparted to the developer. For the same reason, a charge control agent equivalent to the one internally added to the developer 7 may be added to these resins and used for forming the resin layer. Lubricating powder can also be added to the resin.

As the conductive particles to be contained in the resin layer formed on the surface of the developing sleeve 3, various shapes such as flaky, fibrous and powdery metals, metal oxides, graphite and carbon black can be used. it can.

FIG. 3 is a sectional view showing a support portion of an elastic blade in another embodiment of the developing device of the invention. In this embodiment, as the support holder 42, a frame body having two support pieces 42a and 42b facing outwards and having a substantially inverted dish-shaped cross section is used, and both ends of the elastic blade 4 are fixed to the frame body.
It is characterized in that the elastic blade 4 is supported and the central portion of the elastic blade 4 except for both ends thereof is brought into contact with the developing sleeve 3. The other structure of this embodiment is the same as that of the previous embodiment described with reference to FIGS.

Also in this embodiment, the contact portion T of the elastic blade 4 with the developing sleeve 3 can be formed in a long area along the rotation direction of the developing sleeve 3 and in a large area. The developer 7 carried on the developing sleeve 3 can be well regulated at the contact portion T, so that a sufficient triboelectric charge can be imparted and the developer 7 can be applied in a uniform thin layer. Therefore, a high-quality image having uniform density and no fog can be stably obtained by the development.

FIG. 4 is a sectional view showing a supporting portion of an elastic blade in still another embodiment of the developing device of the present invention.
In this embodiment, an endless annular elastic blade is used as the elastic blade 4, and the annular elastic blade 4 is separated at two positions along the rotation direction of the developing sleeve 3, that is, the elastic blade in this example. The side opposite to the developing sleeve 3 side of No. 4 is fixed and supported by the support holder 42, and the developing sleeve 3 side portion of the elastic blade 4 is brought into contact with the developing sleeve 3. The other structure of this embodiment is the same as that of the previous embodiment described with reference to FIGS.

Also in this embodiment, similarly, the contact portion T of the elastic blade 4 with the developing sleeve 3 can be formed in a long area along the rotation direction of the developing sleeve 3 to have a large area. The developer 7 carried on the developing sleeve 3 can be well regulated at the contact portion T with the developing roller 3 so that a sufficient triboelectric charge can be imparted and the developer 7 can be applied in a uniform thin layer. . Therefore, a high-quality image having uniform density and no fog can be stably obtained by the development.

[0030]

As described above, in the developing device of the present invention, the developer carrying member carrying the one-component non-magnetic developer is provided with the developer regulating member, and the developer carrying body of the regulating member is rotated. Since the supporting member is supported at two positions spaced along the direction and elastically abuts on the developer carrying member at the portion between the supporting members, the contact portion of the regulating member with the developer carrying member is made to be the developer. It can be formed in a large area, which is long in the rotating direction of the carrier, and therefore, the one-component non-magnetic developer on the developer carrier is well regulated to impart sufficient triboelectric charge to the developer. It can be applied as a uniform thin layer on the developer carrying member. Therefore, a high-quality image having uniform density and no fog can be stably obtained by the development.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a developing device of the present invention.

FIG. 2 is a sectional view showing a support portion of an elastic blade of the developing device of FIG.

FIG. 3 is a sectional view showing a supporting portion of an elastic blade in another embodiment of the developing device of the invention.

FIG. 4 is a sectional view showing a supporting portion of an elastic blade in another embodiment of the developing device of the invention.

FIG. 5 is a sectional view showing a conventional developing device.

[Explanation of symbols]

1 photosensitive drum 2 Development container 3 Development sleeve 4 elastic blade 5 supply rollers 7 One-component non-magnetic developer 42 Support holder

Claims (2)

[Claims] 1. A one-component non-magnetic developer carried on a developer carrying body is regulated by a developer regulating member elastically abutting on the developer carrying body, and the one component non-magnetic developer is provided on the developer carrying body. In a developing device that conveys the developer to a developing unit facing the image carrier by rotating the developer carrier while forming a thin layer of the developer, the regulating member is used to rotate the developer carrier. A developing device in which the regulating member is elastically abutted against the developer carrying member at a portion between the supporting members by supporting the regulating member at two positions separated along the moving direction. 2. The developing device according to claim 1, wherein the developer is carried on the developer carrier by being supplied by a supply roller elastically abutting on the developer carrier.