JPH02108082A - Developing device for one-component toner - Google Patents

Abstract

PURPOSE:To make uniform a toner layer in the full length of a sleeve by composing a developer carrier of a metallic shaft covered with a conductive elastic body and energizing both longitudinal ends of a plate material toward the developer carrier by means of a spring member. CONSTITUTION:The sleeve 3 is composed of the elastic body with conductivity, and the elastic member 6 pushing the edges to the side of the sleeve 3 is fitted to both longitudinal ends of a developer layer thickness regulating member 5. Consequently, the resilience of the elastic member 6 can make up for the insufficient press-contact force of the sleeve 3 on both ends of a blade 5. As a result, the thickness of the toner layer on the sleeve carried to a developing area becomes uniform, and an obtained picture free of density irregularity is of high grade. Even if the plate material 5 has distortion, it hardly exerts influence on image formation, because the material closely adheres owing to the bending of the conductive elastic body composing the sleeve 3.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a copying machine using a monocomponent toner as a developer;
The present invention relates to an electrostatic latent image developing device in a laser printer or the like.

Conventional technology In general, regarding the phenomenon of electrostatic latent images, there are two methods: one is to develop using a two-component developer consisting of toner and a carrier, and the other is to use a one-component developer consisting only of toner without using carrier. There is a developing method.

- The component development method requires a toner concentration control device in order to always maintain the mixing ratio of toner and carrier, that is, the toner concentration, at an appropriate value, and this toner concentration control device is very expensive and requires Adjustment work was also necessary, and maintenance and inspections were also complicated. Therefore, in recent years, in view of this point, an expensive toner concentration control device is no longer necessary.
Development methods that require no maintenance have been attracting attention.

As a developing method that satisfies such requirements, there is a one-component developing method that uses a developer made only of toner without using a carrier. In this -component development method, a one-component non-magnetic toner layer is formed on a toner carrier made of a conductive metal, and the toner is triboelectrically charged to a predetermined polarity by a triboelectric charging member. The gap between the electrostatic latent image carrier and the toner carrier is increased, and a voltage is applied between the electrostatic latent image carrier and the toner carrier. The first method of developing an electrostatic latent image by flying toner onto the body (Journal of Electrophotographic Society Vol. 26 No. 2)
1987)), by forming a magnetic brush made of conductive one-component magnetic toner on a conductive metal toner carrier containing a magnetic roller, and rubbing the electrostatic latent image carrier with the magnetic brush. A second method for developing electrostatic latent images (US Pat. No. 3,909,258) involves forming a thin layer of electrically insulating monocomponent magnetic toner on a conductive metal toner carrier containing a magnetic roller. The gap between the electrostatic latent image carrier and the toner carrier is made larger than the toner layer, and an alternating current voltage is applied between the electrostatic latent image carrier and the toner carrier to transfer the toner to the electrostatic latent image. A third method of developing an electrostatic latent image by reciprocating the toner carrier and the toner carrier (Japanese Patent Laid-Open No. 18659/1983), in which the toner carrier is adjacent to the electrostatic latent image carrier. The toner carrier includes a conductive support and a plurality of microelectrodes that are electrically insulated from each other, and the toner carrier includes a conductive support and a plurality of microelectrodes that are electrically insulated from each other. A fourth step of triboelectrically charging the upper toner to a predetermined polarity using a triboelectric charging member and developing an electrostatic latent image by applying a constant voltage to the conductive support and the back electrode of the electrostatic latent image carrier. (Japanese Unexamined Patent Publication No. 57-114163) and the like are generally well known.

By the way, there are devices as shown in FIGS. 4 to 6 that form a thin layer of toner on a toner carrier. In Figure 4, 1 is the developing device housing, 2
9 is a rotatably supported developer carrier (hereinafter referred to as a sleeve); 10 is a developer layer thickness regulating member (blade) that supplies the toner 2 to the sleeve 3 and thins it; ), and the blade 10 is generally made of metal, hard rubber, plastic, etc., and is set so as to be brought into pressure contact with the sleeve 3. In addition, in FIG. 5, there is a developer layer thickness regulating member (blade) made of rubber or plastic in the part that comes into contact with the sleeve 3.
The blade 11 is pressed against the sleeve 3 by a metal thin plate spring 12 to which the blade 11 is attached.

Further, in FIG. 6, a magnet 13 is embedded inside the sleeve 3 and extends over the image forming width of the photoreceptor. Reference numeral 15 denotes a rod-shaped magnet, which is fixed to the thin plate-shaped magnet support member 14 with an adhesive or the like. Further, in the case shown in FIG. 6, the layer thickness of the developer is made uniform by using the magnet 13 of 1u11 of the sleeve 3 and the rod-shaped magnet 15.

Problems to be Solved by the Invention In the types shown in FIGS. 4 and 5, it was difficult to make the toner layer thickness uniform over the entire length of the sleeve 3. . That is, blade 10.
Since the pressure contact force is insufficient at both ends of the toner 11, the toner layer at both ends becomes thick, which causes density unevenness in the image. Further, if the blade is distorted, the thickness of the toner layer changes, causing the same problem as described above. Furthermore, the device shown in FIG. 6 requires a bar magnet 15, which is expensive, and in the case of magnetic toner, there is a drawback that the toner is attracted to and adheres to the bar magnet.

Therefore, the present invention is designed to make the toner layer thickness uniform over the entire length of the sleeve with a simple structure.

Means for Solving the Problems In order to solve the above-mentioned problems, the one-component toner developing device of the present invention has a sleeve made of a conductive elastic body, and a flat metal plate material is used to extend the length of the sleeve. Elastic members are arranged parallel to the direction and attached to both ends of the plate material to press these parts toward the sleeve side.

action The effect of this technical means is as follows.

In other words, the pressure contact force with the sleeve that was insufficient at both ends of the plate material is compensated for by the elastic member, and even if the plate material is distorted, the p'j7 conductive elastic body constituting the sleeve is By bending, it will come into close contact.

Embodiment Hereinafter, one embodiment of the present invention will be described based on the drawings. In Fig. 1, ■ is a developing device housing, 2 is a one-component developer (toner), and 3 is a sleeve, which is a metal shaft 3a.
is covered with a conductive elastic body 3b. The sleeve 3 is rotatable by supporting the metal shaft 3 with a support member (not shown).

Further, as this conductive elastic body, silicone rubber or the like into which carbon particles are kneaded is used. 4 is a photoreceptor, 5
is a developer layer thickness regulating member made of a thin metal plate (the one shown in the figure is bent to increase its strength).
blade). Reference numeral 6 denotes spring members that press the plate 5 against the sleeve 3, and as shown in FIG. One spring member is provided at each end, and the elastic force of the spring member located at both ends and the spring member located at the center is adjusted so that the entire blade 5 is pressed against the sleeve with a substantially uniform force. ing. To explain the operation here, as the sleeve 3 rotates in the direction of arrow A, the toner 2 in the developing device housing 1 is carried while adhering to the outer peripheral surface of the sleeve 3, and the plate 5 makes the toner layer uniform in thickness. It is thinned and charged by rubbing against the plate 5, and then transported to a developing area facing the photoreceptor 4, where the latent image on the photoreceptor is visualized. As a result, an image without density unevenness can be obtained over the entire width of the image area. Further, even if there is a slight distortion in the plate 5, the distortion will hardly have an adverse effect due to the deflection of the conductive elastic body 3b of the sleeve.

FIG. 3 shows another embodiment, in which one end of the blade 5 is bent toward the side opposite to the sleeve 3, and spring members are attached to at least both ends of the bent end surface, so that the plate 5' can be attached to the sleeve. This configuration is effective when the plate 5' is particularly thin.

Effects of the Invention As described above, according to the present invention, in a developing device using one-component toner, the sleeve is made of a conductive elastic body, and the developer layer thickness regulating member (plate) is made of a conductive elastic material. By attaching elastic members to both ends in the longitudinal direction that press these parts toward the sleeve, the elastic force of the elastic members can relieve the insufficient pressure contact force with the sleeve at both ends of the blade. Since the toner layer can be supplemented, the thickness of the toner layer on the sleeve carried to the development area is uniform throughout, and the obtained image is also of high quality without density unevenness. Further, even if the plate material is distorted, the conductive elastic body constituting the sleeve flexes and the sleeves are brought into close contact with each other, so the distortion hardly has any adverse effect on image formation. Furthermore, as described above, it has a simple configuration and has the advantage of being able to obtain high-quality images at low cost.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a developing device according to an embodiment of the present invention.
2 is a cross-sectional view taken along the line CC in FIG. 1, and FIG. 3 is a sectional view showing another embodiment of the present invention. FIG. 4, FIG. 5, and FIG. 6 are cross-sectional views of a conventional developing device. 1...Developing device housing 3...Developer carrier (sleeve) 3a...Metal shaft 3b...Electroconductive elastic body 4...Photoreceptor 5...Developer layer Thickness regulating member (blade) 6...
Spring member 10.11...Developer layer thickness regulating member (blade) 1
2... Thin plate spring 13... Magnet 14... Magnet support member 15... Bar-shaped magnet

Claims (1)

[Claims] A developer carrier arranged to face the image carrier and configured to be able to carry a developer made of one-component toner on its surface and to be rotatable; and a developer supply for supplying the developer to the developer carrier. and a metal plate whose smooth surface is in contact with a developer carrier, the developer carrier is constructed by covering a metal shaft with a conductive elastic body, and the plate has a flat surface that is in contact with the developer carrier. A developing device for one-component toner, characterized in that both ends in the longitudinal direction are biased toward the developer carrier by a spring member.