JPH05181355A - Developing device for image forming device - Google Patents

Abstract

PURPOSE:To prevent the generation of density unevenness of an image by electrostatic attraction of toner by connecting a developer carrier to a developer regulating member through a connecting means. CONSTITUTION:Both the ends of a continuing means 14 are laid between respective end parts 12' and 13' of a developer carrier 12 and a regulating member 13. A developer (toner) accumulated in a flat developer receiving chamber 10 is moved on a discharge hole side while being stirred by a stirring plate, then adhered to the developing sleeve of the developer carrier 12, and advanced to a linear contact area between the regulating member 12 and the developing sleeve. The adhered toner layer is regulated in a determined layer thickness in this linear contact area, passed through it, and transferred to a photoreceptor drum. At this time, a static electricity is then generated by the friction between the regulating member 13 and the toner layer. However, since the regulating member 13 and the developing sleeve can be continued to each other through the continuing means 14, and the both are regularly kept at the same potential, the toner adhering phenomenon on the regulating member 13 side by electrostatic attraction is never caused.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a developing device for supplying a developer onto an image carrier in an image forming apparatus such as a copying machine.

[0002]

2. Description of the Related Art Generally, an electrophotographic image forming apparatus typified by a copying machine or the like forms an electrostatic latent image on a photoconductor (drum or belt) and then develops it by a developer carrier of a developing device. An agent (a mixture of toner and carrier) is supplied onto a photoconductor to be converted into a toner image, and the toner image is transferred onto a recording paper to form an image. In this case, how to accurately and uniformly control the layer thickness of the toner adhered on the developer carrying member (developing sleeve) is important for obtaining a good quality image.

Regarding the control of the toner layer thickness, in the developing device of the conventional image forming apparatus, a regulating member is fixedly provided near the developer carrying member, and the toner layer thickness is controlled by adjusting the distance between the roller and the regulating plate. The method of doing was widely known. However, this method has drawbacks in that strict control is difficult because the interval must be adjusted in units of μm, and long-term stability is also impaired. Therefore, a method has been proposed in which the regulating member is urged so as to come into line contact with the surface of the developer carrier to control the layer thickness of the toner. In this system, the toner adhering to the developer carrying member passes through the line contact region against the biasing force of the regulating member that is in close contact with the developer carrying member to control the toner layer thickness.

[0004]

However, in the above-mentioned conventional developing device, the regulating member is charged by friction with the toner during long-time operation, and the regulating member and the developer carrier repeatedly contact and separate. As a result, a potential difference occurs between the two, which makes them unstable. That is, as a result, a part of the toner layer to be attached to the surface of the developer carrying member is electrostatically adsorbed on the regulating member side, and horizontal stripe-shaped unevenness is generated in the final formed image. The present invention has been made in view of the above points, and an object thereof is to provide a developing device of an image forming apparatus in which there is no fear of image quality deterioration due to such electrostatic action.

[0005]

In order to achieve the above object, the developing device of the image forming apparatus of the present invention is a developing device urged so as to regulate the layer thickness of the developer by making line contact with the developer carrier. In a developing device including a developer regulating member, the developer carrying member and the developer regulating member are connected by a conducting means so that the developer carrying body and the regulating member are always at the same potential, and electrostatic attraction of toner is obtained. It is configured to prevent the phenomenon.

A second structure of the present invention is claim 1.
In the developing device described above, a developing sleeve and a magnet roller are provided inside the developing sleeve, and the developer regulating member is configured to be biased by magnetic attraction of the magnet roller, and the strength and the magnetic force of the spring for biasing the regulating member. The thickness of the toner layer can be precisely controlled with a simple structure by appropriately selecting the strength of the toner.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in the accompanying drawings. FIG. 1 is a cross-sectional view showing an overall configuration of a developing device of the image forming apparatus of the present application, and FIG. 2 is a perspective view showing a mounting state of a conducting member.

In the figure, 1 is the main body of the developing device of the present invention,
The main body 1 is arranged near the photosensitive drum K of the image forming apparatus. The main body 1 of the developing device includes a flat developer storage chamber 10, a container-shaped developer stirring plate 11, and the storage chamber 10.
The developer carrying member 12 is provided near the toner discharge port 10a. Here, the developer carrying member 12
Is a surface-magnetized fixed magnet roller 12a and a developing sleeve 12 rotatable around the fixed magnet roller 12a.
b. The developing sleeve 12b is configured such that the developing area thereof is close to the surface of the photosensitive drum K, and the developing sleeve 12b is in contact with the drum K in the non-developing area to be rotationally transmitted.

The developer storage chamber 10 has a bottom surface 10b.
Is gradually inclined toward the toner discharge port 10a at the side end portion, so that the flow of the developer can be promoted. A toner remaining amount detecting sensor S is embedded in the center of the bottom surface 10b so as to expose the sensing surface.
The sensor S is configured to detect the remaining amount of toner by detecting the vibration characteristic on the sensing surface, which changes depending on the presence or absence of toner, by the piezo element.

The agitating plate 11 is made of an elastic member having a crossbar (fin) 11b arranged on an outer frame 11a, and can reciprocate along the flat bottom surface 11b of the developer accommodating chamber 10 to drive the chamber. Is configured. That is, the stirring plate 11 is connected to the crank portion C of the driving side J ₂ through an arm member, and the circular movement of the crank portion C performed by the rotation of the driving shaft J ₂ causes forward movement → upward movement → reverse movement → lowering → It is configured to reciprocate while ascending and descending in the order of forward movement, and during the movement, the outer frame 11a and the cross bar (fin) 11
With b, the inside of the developer storage chamber 10 can be uniformly stirred.

Reference numeral 11c denotes a member for sweeping the surface of the toner remaining amount detecting sensor S. The sweeping member 11c is provided on the fin 11b of the stirring plate 11, and sweeps the surface of the sensor S when the stirring plate 11 moves forward. , Its detection sensitivity can be refreshed.

Reference numeral 13 denotes a toner regulating member, which is a regulating member 13.
Is arranged directly above the developer carrying member 12 so as to be vertically movable. The regulating member 13 is made of a magnetic material, and is configured to be magnetically attracted by the magnet roller 12a and come into line contact with the surface of the developing sleeve 12b. That is, the toner adhering to the surface of the developing sleeve 12b is pressed by the self-weight of the regulating member 13 and the magnetic attraction force of the magnet roller 12a so that it can pass through the line contact region with a predetermined layer thickness. .. The shape of the regulating member 13 may be any rod-like member that can be in line contact with the developing sleeve 12b, but in the present embodiment, it is rotated by an external force to facilitate cleaning when foreign matter or toner lumps adhere. It has a possible roller structure.

Reference numeral 14 is a conducting means, and both ends of the conducting means 14 are provided between the developer carrying member 12 and the respective end portions 12 'and 13' of the regulating member 13 so that they can be always kept at the same potential. Is configured. In the present embodiment, the conducting means 14 is composed of a coil spring and is easy to install,
Although it is possible to follow the vertical movement of the regulating member 13, it is needless to say that the regulating member 13 may be composed of a conductive brush or a flexible lead wire. In addition, the upper space of the regulating member 13 is filled with a leak preventing member M made of a sponge body,
A phenomenon may be prevented in which the developer wraps around from the upper side of the regulation member 13 and leaks to the photosensitive drum K side. Further, the regulating member 13 may be urged by a sponge body of this kind to serve as an auxiliary means for forming a very thin toner layer.

In the above embodiment, the developer (toner) accumulated in the flat developer storage chamber 10 moves to the discharge port 10a side while being stirred by the stirring plate 11, and then the developing sleeve of the developer carrier 12 12b, and the regulation member 13
And the line contact area of the developing sleeve 12b. In this line contact area, the adhered toner layer is regulated so as to have a predetermined layer thickness, passes through, and is transferred to the photosensitive drum K. At this time, the regulating member 13 and the toner layer generate static electricity due to friction, but the regulating member 13 and the developing sleeve 12b can be conducted through the conducting means 14, and both are always maintained at the same potential, so that the electrostatic force is generated. The phenomenon of toner adhesion to the regulating member 13 side due to adsorption does not occur.

The present invention is not limited to the above-mentioned embodiment, but can be applied to any method as long as the conductive member is pressed against the developer carrying member to regulate the developer amount. For example,
As shown in FIG. 3, even in the configuration in which the metal blade 15 is pressed against the developer carrying member 12 to regulate the amount of the developer, the blade 15 and the developer carrying member 12 are electrically connected by the conducting means 14 to prevent static electricity. Can be given.

[0016]

As described above, the developing device of the image forming apparatus according to the present invention is provided with the developer regulating member urged so as to regulate the layer thickness of the developer by making line contact with the developer carrying member. In the developing device, the developer carrying member and the developer regulating member are connected by a conducting means, and the developer carrying member and the regulating member are connected by a conductive member. The same potential is always maintained between the control member and the regulating member, and the electrostatic attraction phenomenon of toner can be prevented. As a result,
This has an effect of preventing uneven density of an image due to electrostatic attraction of toner.

According to a second aspect of the present invention, in the developing device according to the first aspect, the developer carrying member includes a developing sleeve and a magnet roller inside thereof, and the developer regulating member is a magnet of the magnet roller. Since it is configured to be biased by suction, the thickness of the toner layer can be precisely controlled with a simple configuration by appropriately selecting the strength of the spring or the strength of the magnetic force that biases the regulating member. It has the effect of being able to.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an overall configuration of a developing device of an image forming apparatus of the present application.

FIG. 2 is a perspective view showing a mounting state of a conducting means.

FIG. 3 is a schematic cross-sectional view showing an example in which a metal carrier is pressed against a developer carrying member.

[Explanation of symbols]

 1 Main Body of Developing Device 10 Developer Storage Chamber 11 Developer Stirring Plate 12 Developer Carrier 12a Magnet Roller 12b Developing Sleeve 13 Toner Regulating Member 14 Conducting Means 15 Metal Blade K Photoreceptor Drum S Toner Level Sensor M Leak Prevention Member

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[Procedure amendment]

[Submission date] January 7, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Added

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

Claims (2)

[Claims] 1. A developing device of an image forming apparatus, comprising a developer regulating member urged to come into contact with a developer carrying member to regulate the layer thickness of the developer. A developing device for an image forming apparatus, wherein the agent regulating members are connected by a conducting means. 2. The developer carrying member includes a developing sleeve and a magnet roller inside thereof, and the developer regulating member is configured to be biased by magnetic attraction of the magnet roller. The developing device of the image forming apparatus according to claim 1, wherein the developing device is a developing device.