JPH03131877A - Developing device - Google Patents

Abstract

PURPOSE:To preclude ground staining with toner at both end parts of an image carrier and to contamination in the device due to the scraping of toner by providing coatings made of insulating members, which are charged electrostatically to the same polarity of the toner of a developer, at both end parts of a developer carrier. CONSTITUTION:Shield plates 7 are provided at both end parts of a developing sleeve 6 so as to surround the part from the position of a nonmagnetic blade 3 to a development position facing the image carrier 1. Further, end part seal members 4 are provided at both end parts of the developing sleeve 6. Those end part seal members 4 are so provided as to cover the parts of both the end parts of the developing sleeve 6 on the opposite sides from the development position from the position of the nonmagnetic blade 3 to the lower part. Further, the coatings 10 made of insulating members are provided at both end parts of the developing sleeve 6. Consequently, toner is prevented from sticking on or moving round to both the end parts of the developing sleeve 6, and the ground staining of both the end parts of the image carrier with toner and the contamination in the device due to the scraping of toner are precluded.

Description

Detailed Description of the Invention No. 1 The present invention relates to a developing device used to develop an electrostatic latent image formed on an image carrier in an image forming apparatus using an electrophotographic method, an electrostatic recording method, or the like. The present invention relates to an apparatus, and particularly to a developing apparatus in which end seal members are disposed at both ends of a developer carrier carrying and transporting developer.

1eΩandl The developing device used in an image forming apparatus using an electrophotographic method, an electrostatic recording method, etc. is shown in FIGS. 3(a) and (b).
As shown in FIG.
The developer 8 is carried on a developing sleeve 6 as a developer carrier having a built-in magnet 5, and is transported to a developing position with the image carrier 1 while regulating the amount of developer 8 to an appropriate amount by a non-magnetic blade 3. In such a developing device, the electrostatic latent image formed on the image carrier L is developed with the developer 8 and visualized as a toner image. Due to the stirring, the toner in the developer 8 scatters from the developer container 2 and contaminates the inside of the image forming apparatus. To prevent this, in addition to the shielding plate 7 for preventing toner scattering, the developing sleeve 6 is used as a sealing means. An end sealing member 4 made of flocked elastic material, elastic resin, etc. is provided at both ends.

However, although it is possible to prevent the toner from the developer 8 in the developer container 2 from flowing out using the toner scattering shielding plate 7 and the sealing member 4, it is possible to prevent the toner from flowing out of the developer 8 in the developer container 2. Since the sealing member 4 cannot be provided at the developing position, the toner scattered in the area where the sealing member 4 is not provided adheres to both ends (metallic mirror surface portions) of the developing sleeve 6.

The adhered toner may fly onto the image carrier 1 due to the developing bias, causing toner background stains on both ends of the image carrier 1, or the toner that has flown onto the image carrier 1 may be scratched by the end sealing material 4. Dropped and spilled toner contaminates the image forming apparatus.

These things also occur when the toner wraps around to both ends of the developing sleeve at the developing position.

Therefore, it is an object of the present invention to prevent toner from adhering to or sneaking around to both ends of a developer carrier such as a developing sleeve, and to prevent scumming caused by toner on both ends of the image carrier and the inside of an image forming apparatus caused by toner scraping. It is an object of the present invention to provide a developing device free from contamination.

in order to The above object is achieved by the developing device of the present invention.

To summarize, the present invention provides a developing device in which end seal members are disposed at both ends of a developer carrier that carries and transports a developer for developing an electrostatic latent image formed on an image carrier. According to one aspect of the present invention, the developing device is characterized in that a coating made of an insulating member that is charged to the same polarity as the toner of the developer is provided at both ends of the developer carrier. The insulating member is triboelectrically charged to the same polarity as the toner by rubbing against the end seal member and the developer.

FIG. 1(a) is a configuration diagram showing one embodiment of the developing device of the present invention, and FIG. 1(b) is a view taken along the line A--A in FIG. 1(a). .

As shown in FIGS. 1(a) and 1(b), the developing device includes a developing sleeve 6 as a developer carrying member installed in a developing container 2 containing a developer 8 so as to be rotatable in the direction of arrow a. ing. A stirring rod 9 for supplying the developer 8 to the developing sleeve 6 is provided in the developing container 2, and a magnet 5 for supporting the supplied developer 8 is installed immovably in the developing sleeve 6. is provided with a non-magnetic blade 3 that regulates the amount of developer 8 carried thereon. The developer 8 carried on the developing sleeve 6 by the magnet 5 is regulated to an appropriate amount by the blade 3, and is conveyed to a developing position facing the image carrier 1 by rotation of the sleeve 8.

In this embodiment, the developing sleeve 6 is made of a non-magnetic material,
The developer 8 is a two-component developer consisting of a negatively charged non-magnetic toner and an insulating resin-coated magnetic carrier. Further, the image carrier 1 is an amorphous Si photoreceptor.

The developer 8 conveyed to the development position with the image carrier 1 forms a magnetic brush by the development pole S of the magnet 5, and the toner is latent by the DC voltage and alternating voltage applied to the development sleeve 6. The toner flies to the image carrier 1 and adheres to the electrostatic latent image on the latent image carrier 1, and the electrostatic latent image is visualized and developed as a toner image.

In order to prevent scattering of the toner that is free or floating from the developer 8 during such a development process, as in the past, a developer is installed at both ends of the developing sleeve 6 from the non-magnetic blade 3 facing the image carrier l. A shielding plate 7 for preventing toner scattering is provided so as to surround the portion that extends to the position. Similarly, end seal members 4 are provided at both ends of the developing sleeve 6.

The end sealing members 4 are provided so as to cover the opposite ends of the developing sleeve 6 from the position of the non-magnetic blade 3 on the side opposite to the developing position. The end sealing member 4 is formed into a U-shaped cross section with a gap 4a, and the sealing member 4 is accommodated in a recess 2b provided in the side wall 2a of the developer container 2, and the filling member 11 is pushed into the gap 4a. By doing so,
A sealing member 4 is pressed against both ends of the developing sleeve 6. The end seal member 4 is made of a tetrafluoroethylene-based elastic resin.

According to the present invention, the coating 10 made of an insulating member is provided at both ends of the developing sleeve 6 in order to more reliably prevent toner from scattering. This coating 10 is triboelectrically charged to the same polarity as the toner in the developer 8 due to the friction between the end seal member 4 and the developer 8. The developing sleeve 6 is made of a fluororesin that is charged to the same polarity as the negatively charged toner, and is formed by uniformly coating the developing sleeve 6 with the fluororesin to a thickness of several tens of micrometers and vacuum baking. The developing sleeve 6 was made of 5US316. As mentioned above, in this embodiment, the end seal member 4 is made of tetrafluoroethylene resin, but in order to more strongly negatively charge the coating 10 made of fluororesin, the end seal member 4 is made of It is preferably formed from an elastic resin such as nylon, polycarbonate, or acrylic.

As an insulating member constituting the above-mentioned coating lO,
When the toner is a negative toner, fluororesin, polyethylene, polypropylene, polyester, etc. can be used. Furthermore, ceramic coating materials such as PVDF can also be used. On the other hand, when the toner is a positive toner, nylon, polycarbonate, acrylic, etc. can be used.

The developing device of the present invention is configured as described above.

As mentioned above, since the sealing member 4 cannot be provided at the development position where the image carrier 1 and the developing sleeve 6 face each other, the toner scattered at the end where the sealing member 4 is not provided is were attached to both ends of the developing sleeve 6. Furthermore, toner adhesion to both ends also occurred due to the toner flowing around to both ends of the developing sleeve at the development position. At this time, in the present invention, since the coating 10 made of fluororesin which is charged to the same polarity as the toner is provided on both ends of the developing sleeve 6, the scattered toner does not adhere to both ends of the developing sleeve 6. For this reason,
Conventionally, adhered toner flies to the image carrier 1 due to the development bias, causing background smudges due to toner on the image carrier 1, and the toner that flies to the image carrier 1 is caused by the edge sealing material 4. This eliminates the phenomenon of toner scattering into the image forming apparatus due to scraping.

Further, according to the present invention, the coating 10 is provided at both ends of the developing sleeve 6, and the coating 10 is provided at both ends of the developing sleeve 6 to prevent sealing failure of the end sealing member 4 and toner leakage from the sealing member 4 due to the sealing failure. Since the coating 1O is charged to the same polarity as the toner, the sealing performance is greatly improved and toner leakage is eliminated.

Furthermore, since the coating 1O is made of fluororesin, the coefficient of sliding friction at both ends of the developing sleeve 6 is reduced, reducing the driving load on the developing sleeve 6 and also reducing the rise in temperature of the sleeve 6 due to friction at both ends of the developing sleeve 6. There are also other effects.

In the above embodiments, a two-component developer consisting of a non-magnetic toner and a magnetic carrier was used as the developer 8, but the present invention is not limited thereto. Component non-magnetic toners can also be used.

FIG. 2(a) is a block diagram showing another embodiment of the developing device of the present invention, and FIG. 2(b) is a view taken along the line A--A in FIG. 2(a).

As shown in FIGS. 2(a) and 2(b), in the developing device of this embodiment, by forming the coating lO thickly on both ends of the developing sleeve 6, the coating lO is formed on both ends of the developing sleeve 6.
A feature is that a step 10a is provided, and a portion of the end seal member 4 on the covering 10 side extends inward along the developing sleeve 6, and a flange portion 4b that covers the step 10a is provided at the extended portion. It is. The other configurations of this developing device are basically the same as those shown in FIGS. 1(a) and (b), and the developing device shown in FIGS. The same reference numerals as the reference numerals denote the same members.

In the developing device of this embodiment, a step 10a formed by the coating 10 is provided at both ends of the developing sleeve 4, and the step 10a is covered by the flange 4b of the extending portion of the end seal member 4, so that toner can be prevented from going around. It is possible to further improve the prevention of toner adhesion to both ends of the developing sleeve 6.

As described above, the present invention provides end seal members at both ends of the developer carrier that supports and transports the developer for developing the electrostatic latent image formed on the image carrier. In the developing device equipped with this, a coating made of an insulating member that is charged to the same polarity as the toner of the developer is provided at both ends of the developer carrier.
It is possible to prevent toner from adhering to and wrapping around both ends of the developer carrier, and to eliminate background smudges caused by toner at both ends of the image carrier and contamination within the image forming apparatus due to scraping of toner.

[Brief explanation of the drawing]

FIG. 1(a) is a block diagram showing one embodiment of the developing device of the present invention, and FIG. 1(b) is a view taken along the line A--A in FIG. 1(a). FIG. 2(a) is a block diagram showing another embodiment of the developing device of the present invention, and FIG. 2(b) is a view taken along the line A--A in FIG. 2(a). FIG. 3(a) is a configuration diagram showing a conventional developing device, and FIG. 3(b) is a view taken along the line A--A in FIG. 3(a). b 0 0a: Image carrier: End sealing member: Flange: Developing sleeve: Developer: Covering: Step Figure 1 (a) Figure 2 (a) -L''-

Claims (1)

[Scope of Claims] 1) A developing device in which end seal members are disposed at both ends of a developer carrier that supports and transports a developer for developing an electrostatic latent image formed on an image carrier. A developing device characterized in that a coating made of an insulating member that is charged to the same polarity as the toner of the developer is provided on both ends of the developer carrier. 2) The developing device according to claim 1, wherein the insulating member is triboelectrically charged to the same polarity as the toner by rubbing against the end seal member and the developer.