JPH0631483Y2 - One-component developing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a one-component developing device used in an electronic copying machine or the like. More specifically, it prevents the developer in the hopper from leaking to the outside. And a one-component developing device.

[Prior Art / Problems to be Solved] A conventional one-component developing device in an electronic copying machine or the like has a structure as shown in FIG. 4, and the developer 3 contained in the hopper 6 is a developer. The electrostatic charge is carried on the developing roll 2 by the rotation of the supply roll 5, then is formed into a developer layer having a predetermined thickness by the regulating member 1 and is triboelectrically charged, and is disposed opposite to the developing roll. It is attracted to the electrostatic latent image on the latent image carrier (not shown) to visualize the latent image.
The seal member 4 fixed to the bottom of the hopper 6 is in contact with the developing roll 2 to prevent the developer in the hopper from leaking to the outside. Also, as shown in FIG.
Between the sealing member 4 and the bottom of the hopper 6, an elastic foam 7 is provided.
It is also practiced to secure the airtight contact between the seal member 4 and the developing roll 2 by inserting the above. However, in these conventional devices, since the developing roll and the seal member are in pressure contact with each other, there is a problem in that the developer on the developing roll is electrostatically adsorbed by the seal member and deposited there.

[Means and Actions for Solving Problems] According to the present invention, the above problems are caused by a hopper having a regulating member that abuts on the surface of the developing roll to form a developer layer on the developing roll and the developing roll. A bottom wall of the hopper, and an insulating film is interposed between an elastic body fixed to the bottom wall of the hopper and the developing roll to insulate the elastic body from the developing roll. In a one-component developing device which makes a surface contact through a transparent film and a one-component developer moves from the developing roll onto the electrostatic latent image holder through the hopper opening to visualize the electrostatic latent image. ,
Claim 1 of the utility model characterized in that the charging polarity of the insulating film is the same as the charging polarity of the developer.
This is solved by the one-component developing device described in the section.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 and FIG. 2 are views showing a developing device of the present invention. An elastic foam 7 fixed to the bottom wall of a hopper 6 is arranged so as to make surface contact with the developing roll 2, and the elastic foam is formed. Adhesion 8 to the elastic foam body, preferably with an insulating film 4 having the same charging polarity as the developer interposed between the body and the developing roll.
To do. This insulating film, as shown in FIG.
The developing roll is made longer than the length (l) of the hopper opening and shorter than the length (L) of the developing roll (that is, the free length of the insulating film is shorter than the length (L) of the developing roll). Are arranged so as to be in surface contact with and overlap with the end seal member 9. According to such a configuration, the developer is prevented from spilling to the outside due to the distortion of each constituent member or the increase in the pressure of the developer, and the insulating film has the same charging polarity as that of the developer. The electrostatic attraction of the developer by the film is mitigated, and the developer is prevented from accumulating.

In FIG. 1, a developing roll 2 and a developer supplying roll 5 are axially supported in a hopper 6 accommodating a developer 3 so as to be rotatable in the arrow directions while being in pressure contact with each other. The regulating member 1 has one end fixed to the upper edge of the hopper opening and the other end abutting the developing roll. The developer 3 is supplied to the developing roll at the contact portion between the developer supply roll 5 and the developing roll 2, and then formed on the charged thin film developer layer having a predetermined thickness by the regulating member 1 to form an electrostatic latent image carrier. The latent image is visualized by being electrostatically attracted to the upper latent image. As the elastic foam, for example, normal urethane foam is fixed to the bottom wall of the hopper. The insulating film 4 is sandwiched between the developing roll and the elastic foam along the elastic foam that deforms according to the shape of the developing roll 2.
Further, it is fixed to the side surface of the elastic foam body by the adhesive layer 8 and regulates the free length of the insulating film itself.

FIG. 2 is a view as seen from the direction of the arrow () in FIG. 1, in which the insulating film 4 is longer than the opening width l of the hopper and shorter than the length L of the developing roll and overlaps with the end seal member 9. In addition, the developer is prevented from leaking from the end portion.

The developer on the insulating film and the developing roll is triboelectrically charged by the rotation of the developing roll, but by using a material with the same polarity as the charging polarity of the developer as the insulating film, It is possible to alleviate the electrostatic adsorption effect of and to prevent the accumulation of the developer. As a specific example, when a negative-polarity developer containing a metal-containing dye was used, when the same negative-polarity Teflon was used as an insulating film, the deposition of the developer did not occur. Similar results were obtained when a negative-polarity substance such as ABS resin, AS resin, vinyl chloride resin, polyolefin resin, polyester resin was used instead of Teflon. For comparison, when a positive-polarity polyimide resin was used, developer deposition occurred. In addition, a quaternary ammonium-containing positive polarity developer is used, and the insulating film is made of polyimide resin, polyamide resin, polyurethane resin,
When it was composed of a positive-polarity substance such as melamine resin, the developer did not deposit in the same manner.

Seal member, that is, insulating film 4, elastic foam 7
The portion constituted by the adhesive layer 8 and the developing layer 2
If the contact pressure is too high or too low, a satisfactory sealing effect cannot be achieved. Therefore, the contact pressure is preferably adjusted within a predetermined pressure range depending on the thickness or hardness of the elastic foam.

FIG. 3 shows another embodiment of the present invention. In this embodiment, an adhesive layer 8 is formed between the developing roll 2 and the elastic foam 7, and the pores of the elastic foam have a minimum particle size or an average particle size (for example, 10 μm) of the developer 3 used.
m) The following are used. For example, the desired elastic foamed body 7 can be obtained by solidifying the urethane liquid foam with the pore diameter kept at 10 μm or less and then removing the skin layer on the surface. For example, Rubicell (trade name) manufactured by Toyo Polymer Co., Ltd. can be used. By doing so, the developer is prevented from entering the pores of the elastic foam, and the side surface of the elastic foam acts as an insulating film.

The elastic foam 7 may be formed into a concave cylindrical bearing surface in accordance with the outer diameter.

According to the developing device of the present invention, the charging polarity of the insulating film interposed between the developing roll at the opening of the hopper and the elastic foam member fixed to the bottom wall of the hopper is controlled by the developer. Since it is set to be the same as that, it is possible to always perform good development without depositing the developer.

[Brief description of drawings]

FIG. 1 is a diagram showing a developing device according to the present invention, and FIG.
FIG. 3 is a view as seen from the direction of the arrow in FIG. 3, FIG. 3 is a view showing another embodiment of the present invention, and FIGS. 4 and 5 are views showing a conventional developing device. 1 ... Regulating member, 2 ... Developing roll, 3 ... Developer, 4 ... Insulating film / sealing member, 5 ... Developer supply roll, 6 ... Hopper, 7 ... Elastic foam, 8 ... … Adhesive layer, 9 …… End seal material.

Claims (1)

[Scope of utility model registration request] 1. A hopper opening formed by a regulating member that comes into contact with a surface of a developing roll to form a developer layer thereon, and a bottom wall of a hopper containing the developing roll,
An insulating film is interposed between the elastic body fixed to the bottom wall of the hopper and the developing roll so that the elastic body and the developing roll are in surface contact with each other through the insulating film, and the hopper opening In the one-component developing device in which the one-component developer moves from the developing roll onto the electrostatic latent image holding member through the section to visualize the electrostatic latent image, the charging polarity of the insulating film is the charging polarity of the developer. A one-component developing device, which is the same as