JPH0361970A - Developing device - Google Patents

Abstract

PURPOSE:To prevent a developer from being electrified to opposite polarity because of rubbing between the developer and a sealing member and to prevent the occurrence of reversal fogging by forming at least a part of the surface of the sealing member brought into contact with a developing roll with a member having electrical conductivity. CONSTITUTION:The sealing member 10 fixed on a container 4 sticks to both back edges of the developing roll 2 so that the developer in the container 4 is prevented from leaking out of the edge parts of the developing roll 2. The container side of the sealing member 10 is formed with a sheep wool felt 10A, and the upper layer of the sealing member, the surface brought into contact with the developing roll 2, is formed with an electrical conductive felt 10B woven out of electrical conductive fiber and 'Teflon(R)' fiber. Thereby, the developer T on both edge parts of the developing roll 2 is prevented from being electrified to the opposite polarity because of rubbing between the developer and the sealing member 10 having the electrical conductivity, and the positive fogging is prevented.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is utilized in the technical field of developing devices, and in particular, the present invention is applied to the technical field of developing devices, and particularly to the development of a developing roll that conveys developer to a developing section and a developer container that accommodates the developing roll. between.

The present invention relates to a device having a sealing member that prevents developer from leaking at the end of the developing roll.

[Prior Art J] In this type of developing device, if developer (hereinafter referred to as toner) spreads outside the developing area in the longitudinal direction of the developing roll or leaks, it causes negative effects such as toner scattering and staining. Conventionally, an elastic member such as maltbrain or felt was brought into close contact with the surface of both end portions of the developing roll over almost the entire circumference to prevent leakage at the end portions.

Furthermore, if a porous elastic material such as the above-mentioned maltblane is used, there is a problem in that it causes toner clogging and hinders subsequent toner removal, so it is recommended to use felt made of a material that has low friction with the developing roll. There were also many.

[Problem to be Solved by the Invention J] However, with such conventional sealing members, it is difficult to ensure dimensional accuracy at the end portions, and since the sealing member is highly flexible, the sealing member and the developing roll may rub against each other due to rotation of the developing roll. As this happens, toner enters the developing roller, and the toner ends up being applied to the non-developing area on the developing roll.

Furthermore, if the frictional charging characteristics between the toner and the sealing member are not appropriate, the toner will be frictionally charged to a polarity opposite to the predetermined charging polarity (hereinafter referred to as reverse toner), and the end portions on the photoreceptor drum will be A problem has arisen in that a reverse fog is developed in the image area. This leads to toner scattering and staining, and in a developing device that uses a member that contacts the photoreceptor drum to transfer the image, such as a transfer roller, this causes the problem that the toner is transferred to a non-image area on the transfer paper as an inversion fog. Become.

A specific example will be shown and explained below. As an end seal member,
Generally, Teflon (tetrafluoroethylene resin, Teflon: trade name of DuPont) is often used. This is because the so-called squeal (fricative noise) is eliminated and the driving torque is also reduced. However, when using negatively charged toner.

Due to friction with the Teflon felt, the toner is positively charged, causing reverse fogging.

The present invention solves the problems of such conventional devices,
It is an object of the present invention to provide a developing device which prevents toner from being charged to the opposite polarity due to friction with a sealing member and eliminates reverse fog.

[Means for Solving the Issues] According to the present invention, the above objects include: a container having an opening on the side and storing a developer; A developing device having a developing roll that carries and conveys developer, and a sealing member that contacts the developing roll and seals the developer with the container at the end of the developing roll, comprising: It is distantly related to forming at least a part of the surface that contacts the roll surface with a conductive member.

[Function] In the above-described particular aspect of the present invention, the developer at both ends of the developing roll is prevented from being charged to opposite polarities due to friction with the conductive seal member.

[Example] Hereinafter, the present invention will be described in detail based on the accompanying drawings.

FIG. 1 is a sectional view of the apparatus of this embodiment, and FIG. 2 is a perspective view showing the developing roll and seal member of the apparatus shown in FIG.

In FIG. 1, the photoreceptor tram l is placed at a negative potential 1, e.g., Vd=-650, by a primary charger (not shown).
After being charged to V, it is exposed to light by an exposure means (not shown) such as a laser beam to form a negative latent image (for example, potential VJI = −
100V) is generated. In such a photosensitive drum, this latent image is visualized by reversal development using a developing device using negatively charged high resistance component magnetic toner.

The developing roll 2, which forms a developing section in close opposition to the photoreceptor drum 1, is made of a non-magnetic material such as stainless steel or aluminum, and is supplied with the magnetic toner T (developer) in the container 4. By rotating in the direction of the arrow, the toner T is supported and conveyed on its circumferential surface. A regulating member 5 made of a magnetic material such as iron is disposed directly above the developing roll 2 at a uniform interval from the developing roll 2. In addition, the magnetic flux of the magnet 6 in the developing roll 2 acts in a concentrated manner with the regulating member 5 to form a magnetic curtain that restrains the magnetic developer, and as a result, the developer layer 3 of a predetermined thickness is spread onto the developing roll. It is formed on the circumferential surface of 2. The thickness of the developer layer 3 is desirably thin enough to be narrower than the distance between the developing roll 2 and the photosensitive drum 1 in the developing section where the photosensitive drum 1 receives developer from the developing roll 2. But it is not limited to this.

The developing roll 2 is supplied with an AC voltage (for example, a rectangular wave 14
00Vpp, 1800) 1x) DC voltage (Vdc=
-500 V) is applied to form an oscillating electric field in the developing section, thereby making it possible to develop the electrostatic latent image.

At both ends of the developing roll 2, as shown in FIG. 2, sealing members lO fixed to the container 4 are in close contact with the back side (inside the container) of the developing roll 2, and the developer inside the container 4 is sealed. leakage from the edge of the developing roll.

In this embodiment, as shown in FIG. 3, the sealing member 10 is made of wool felt IOA on the container side, and the upper layer, that is, the surface in contact with the developing roll 2, is made of conductive fiber (15 g wire diameter dyed with copper ions). , acrylic fiber with a resistivity of 10 Ωcm) and Teflon fiber in a ratio of 5=5. This is seal member 10
This is to improve the adhesion between the developing roll 2 and the developing roll 2, and to reduce friction.

If the sealing member of this embodiment is adopted, even if the adhesion between the sealing member 10 and the developing roll 2 or the sealing member 10
Even if the edge forming is incomplete and a small amount of toner leaks between the sealing member 10 and the developing roll 2, the toner will be charged to a negative polarity (predetermined polarity) by friction with the conductive fibers. , no inverted toner is generated. Furthermore, since the conductive fibers are grounded via the developing roll 2, even if some reversed toner is generated due to friction with the conductive felt, the toner is neutralized by contact with the conductive fibers and charged to a predetermined polarity. It has been confirmed that if two or more sides of the surface in contact with the developing roll 2 are made of conductive fibers, there is an effect of preventing reverse fogging.

Further, in this embodiment, a developing device that performs reversal development using a negatively chargeable high-resistance component magnetic toner has been described, but the present invention can be applied regardless of the charging characteristics of the toner, and can be applied to either regular or reversal development. It can also be applied to Similar effects can also be obtained with non-magnetic component and two-component developers. Furthermore, it goes without saying that the present invention can also be applied to a developing device configured to form a layer of developer by bringing an elastic body such as urethane rubber into contact with a developing roll.

In this example, a felt made of woven conductive fibers and Teflon fibers was used as the sealing member on the surface in contact with the developing roll, but the material is not limited to this. For example, a similar effect could be obtained by coating the surface of Teflon felt with a resin in which conductive particles such as carbon were dispersed (for example, one having a specific resistance of 10'Ωcm). Furthermore, similar effects were obtained when a polyvinylidene fluoride sheet (having a specific resistance of 106 Ωcm) was used as a sealing member. These members have the effect of reducing the amount of frictional charge on the toner and eliminating static electricity from the toner.

Further, the conductive member does not need to be disposed on the entire surface of the sealing member, but if it is disposed at least on the part of the sealing member on the opening side of the developer container as shown in FIG. 4, it is effective to prevent the generation of reversed toner. There is.

[Effects of the Invention] As described above, the present invention includes a sealing member for preventing toner leakage from both ends of the developing roll, in which at least a portion of the surface in contact with the developing roll is made of a conductive member. Therefore, it is possible to prevent the toner from being charged to the opposite polarity due to friction with the sealing member, resulting in the effect of eliminating reverse fog.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the apparatus of the present invention, FIG. 2 is a perspective view showing the developing roll and sealing member of the apparatus shown in FIG. 1, and FIG. 3 is an enlarged perspective view showing the sealing member of FIG. 2. FIG. 4 is a perspective view showing a modification of the sealing member shown in FIG. 2. 2...Developing roll 4...Container 10...Sealing member 10B-...Conductive member (conductive felt)

Claims (1)

[Scope of Claims] A container having an opening on the side and storing a developer, a developing roll having a portion protruding from the opening and being housed in the container and carrying the developer on its surface for transport; In a developing device having a sealing member that contacts the developing roll and seals the developer with the container at the end of the developing roll, at least a part of the surface of the sealing member that contacts the developing roll surface is made of a conductive member. A developing device characterized by: