JPS6289075A - Developing device - Google Patents

Abstract

PURPOSE:To prevent the clogging of toner in perforated parts by providing a hairy cleaning member that contacts the outside of a perforated electrode board in a developing device. CONSTITUTION:A hairy cleaning member 11 is provided in the lower part of inside of a container 10 of the developing device 1, and the tip of hair is slightly smaller than hole diameter of a perforated electrode sleeve 16. The hairy member 11 is a fur brush screw made by setting hair spirally on a shaft and makes the carrying action of developer as well as cleaning action. The spiral hairy member 11 and a developing screw 12 are formed as an integral screw and developer is carried by both rotations, and sent upward at the end part, and sent to the inside of the sleeve 16. Developer is electrostatically charged sufficiently by the action of a magnet 13 and deposited to outer face of the sleeve 16, and becomes a toner layer having uniform thickness by the action of a blade 14 and faces a photosensitive body 2. It sticks to an electrostatic latent image formed on the photosensitive body 2 to form the latent image visible. Unused toner is scraped off from the sleeve 16 and used again. The hairy member 11 scrapes off the toner from the sleeve 16 and prevents the clogging.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing device for developing a latent image such as an electrostatic latent image formed on an image carrier, and particularly to a two-component non-contact developing device.

Conventionally, in the so-called mesh development method using a metal mesh, etc., when the metal mesh is fixed, it is not possible to recover the developer (hereinafter also referred to as toner) that is not consumed during development, and the toner is There is a disadvantage that the image is contaminated by splashing and spilling, and on the other hand, there is a disadvantage that the size of the device increases even if the device is moved. In any case,
Since the toner and carrier are stirred and transported by separate means, the apparatus becomes complicated and large, which is a problem. To solve this problem, a developing device has been proposed in which a perforated electrode plate is configured as an endless carrier and rotated, but the holes become clogged with use or under high temperature and high humidity conditions. There is a problem that the image quality deteriorates significantly.

The present invention aims to solve the above-mentioned drawbacks in a developer device using an endlessly movable perforated electrode plate, and to provide a developing device in which clogging does not occur in the holes of the perforated electrode plate. purpose.

According to the present invention, there is provided a developer holding member that holds a developer containing non-magnetic toner capable of retaining a charge and magnetic carrier particles having a particle size larger than that of the toner, and an outer surface of the developer holding member. It is provided on an endlessly movable surface while rubbing against the developer, and has a large number of openings larger than the particle size of the toner particles and smaller than the carrier particles, and only the toner particles are exposed to the outside by sliding against the developer. a perforated electrode plate to be deposited, a means for attaching the deposited toner particles to the latent image while keeping the perforated electrode plate and the image bearing member to be developed in non-contact, and bristles that contact the outside of the perforated electrode plate. Since the developing device is provided with a cleaning member having a shape, it is possible to effectively prevent the holes from being clogged with toner.

Fig. 1 shows an electrophotographic image forming apparatus equipped with a developing bag N1 according to the present invention, Fig. 1 shows a cross-sectional view of the developing device of this embodiment, and Fig. 2 similarly shows a longitudinal sectional view. It is shown.

The image forming apparatus has a photosensitive drum 2 which is an image bearing member, and a latent image is formed on the surface of the drum by a means placed around the drum, and the latent image is developed by the developing bag ml according to the present invention. It is something. Around the photosensitive tram 2, for image formation, there are a corona charger 3, a developing device 1, a transfer separation charger 4. A pre-clean static eliminator 5 and cleaning means 6 are provided. At the position of the arrow indicated by reference numeral 7,
The photosensitive drum 2 that uniformly receives the pre-exposure light is a corona charger 3
Is it uniformly charged by that? &! Image exposure is performed at the position of the arrow indicated by reference numeral 8, whereby the charge on the photosensitive drum z disappears in accordance with the exposure, and an electrostatic latent image is formed. This latent image is developed by the developing device 1 according to the present invention, and the developed R image is transferred by the transfer charger 4 onto the transfer paper conveyed by the roller 9. The transferred toner image is fixed onto the transfer paper by a fixing device (not shown).

After the transfer, the photosensitive drum 2 is subjected to the action of the pre-clean static eliminator 5, and then residual toner is removed by the cleaning means 6, in preparation for the next image formation.

Next, the developing device 1 of the present invention will be explained in detail. The developing device 1 has a container 10, and a developer is stored in the lower part of the container. The developer is a two-component developer containing toner particles and magnetic carrier particles.

A perforated electrode member 16 is provided inside the container 10 . In this embodiment, the perforated electrode member 16 is made of conductive metal, has an endless shape, and is a perforated electrode sleeve capable of endless movement in the direction of the arrow. may be the same as or opposite to the moving direction of the photoreceptor 2. The perforated electrode sleeve 16 has a large number of minute openings, and the diameter of the opening is .

For example, in order to satisfy this requirement, SUS with an outer diameter of 20 mm and a thickness of 0° and 4 mm is used.
Using a CO2 laser, holes with a diameter of 100 gm or less were formed in a lattice shape with an interval of 300 gm. This processing is not limited to the use of laser, but may also be etching or electric field etching. The toner used has an average particle size of about 10 pm, while the carrier particles have a particle size of about 200 m.

The container IO has an opening 15 through which the outer surface of the perforated sleeve 16 faces the photosensitive drum 2 .

A hair-like cleaning member 11 is provided inside and below the container 10 . Preferably, the tip of the bristles is smaller than the diameter of the hole in the perforated electrode sleeve 16, that is, in this embodiment, lo
It is preferable that it is 0.07 pm or less. In this embodiment, the hair-like cleaning member is a fur brush screw with hairs flocked spirally on the shaft, and the outer size of the fur brush screw 11, which performs the cleaning action and the developer transport action, is It is large enough to contact both the hole electrode sleeve 16 and the developer at the bottom of the container 10. Although the fur brush screw 11 may be stopped or rotated in either direction, it is preferable that the fur brush screw 11 has a relative speed with the perforated electrode member 16. 11 is the direction of the arrow, that is, the sleeve 16
The spiral fur brush screw 11 and the developing screw can be rotated in the same direction as the spiral fur brush screw 11 and the developing screw. 12 is formed as an integral screw, and the fur brush screw and the screw 12 are rotated in the direction of the arrow in FIG. 1 by the drive gear 22. As a result, the developer is conveyed to the right in FIG. 2, and is sent upward, ie, into the interior of the sleeve 16, by the screw 24 at the right end.

The developer sent into the sleeve is conveyed from one axial end to the other end in the direction of the arrow in FIG. After reaching the other end, it returns to the fur brush screw 11 by gravity. In this way, the developer is transferred to container 1.
0 and the inside of the perforated electrode sleeve 16.

A magnet 13 is provided outside the perforated electrode sleeve 16 on the downstream side (with respect to the rotational direction of the sleeve 16) of the portion facing the photoconductor 2, and this magnet 13 causes a magnetic brush extending from the developing screw 12 to The magnetic brush reaches the perforated pole sleeve 16 and comes into contact with and rubs against it. That is, the rotation of the developing screw 12 and the perforated electrode sleeve 16 forcibly rubs the perforated electrode sleeve 16, the carrier particles, and the toner particles. This rubbing imparts a sufficient charge to the toner, and the carrier moves toward the perforated electrode due to the magnetic attraction of the magnet 13, and the toner particles pass through the micro openings of the perforated electrode sleeve 16 to the perforated electrode. The toner is deposited on the outer surface of the sleeve 16, forming a layer of toner thereon. A scraper blade 14 is provided on the downstream side of the magnet, and the scraper 14 serves to regulate the thickness of the toner layer formed by the above-mentioned deposition and uniformly coat the perforated electrode cylinder with the deposited toner.

The perforated electrode sleeve 16 and the photosensitive drum 2 have a diameter of 100 to 50
0gmfli1, and by alternating voltages applied between them, the toner, once formed as a toner layer by the deposition, flies back and forth between the photosensitive drum 2 and the outer surface of the perforated electrode sleeve 16, and the photosensitive drum z Develop the upper electrostatic latent image with very little fog. Since this developing process is basically the same as that described in Japanese Patent Publication No. 58-32375, detailed explanation will be omitted.

In operation, the perforated electrode sleeve 16, the fur brush screw 11, and the screw 12 rotate in the directions of the arrows, and the developer in the lower part of the container 10 is conveyed into the perforated electrode sleeve 16, and the action of the magnet 13, etc. The toner particles are sufficiently charged and deposited on the outer surface of the perforated electrode sleeve 16, and are formed into a single layer of uniform thickness by the action of the blade 14, facing the photoreceptor 2. Here, the developer adheres to the electrostatic latent image formed on the photoreceptor 2 and visualizes the latent image. The toner not consumed in development is scraped off from the perforated electrode sleeve 16 by the fur brush screw 11, mixed and stirred with the developer in the lower part of the container 10, and reused. Therefore, toner is effectively utilized.

In addition, this fur brush screw 11 has a size and position that makes contact with the outer surface of the one-hole electrode sleeve 16, so that it can reliably scrape off toner from the perforated electrode sleeve 16 and remove the toner from the perforated electrode sleeve 16. Clogging of holes can be reliably prevented.

The developing device l according to the present invention is actually constructed.

A comparison was made between one without the fur brush screw 11 and one with it (an example of the present invention) operated under relatively high temperature and high humidity (35° C. 90%) conditions. Photosensitive drum 2
When we tried intermittent development using an organic semiconductor as an organic semiconductor, we found that with an apparatus that did not use the fur brush screw 11, the perforated electrode sleeve 16 became clogged and the sleeve became contaminated (toner adhered to the sleeve surface and new toner (no charge is applied from the sleeve) occurs,
The image quality deteriorated (ground blurring, decrease in image density).In contrast, with the developing device of the present invention, the initial image quality was maintained up to 30,000 sheets, and no clogging was observed. In this experiment, the AC voltage (peak-to-peak value) was 15
00V and the frequency was 1500Hz.

FIG. 3 is a sectional view of a developing device according to another embodiment of the present invention. In the embodiment described above, the fur brush 11 had a conveying function in addition to the cleaning function, but in this embodiment, although the fur brush 11 had a cleaning function, it did not have a conveying function to the inside of the perforated electrode sleeve 16. The conveying action is carried out by a separate conveying screw 25. This conveyance screw 25 is connected to the screw 12 at the l end, similar to the fur brush 11 of the previous embodiment. The fur brush 11 is simply pivoted at both ends.The rest of the structure in this embodiment is the same as that in FIG. Replace.

In this embodiment as well, the fur brush 11 comes into contact with the surface of the perforated electrode sleeve 16, and as in the previous embodiment, the fur brush 11 has the effect of preventing clogging.

In addition, in the description of the embodiment described above, it is assumed that a conveying screw is provided inside the perforated electrode screw 16.
The internal screws may also be formed with a fur brush in the same way as the external screws, and in this case the cleaning effect can be more reliably obtained.

As explained above, according to the present invention, it is possible to prevent the perforated electrode member (sleeve) from clogging with toner, so even under adverse conditions of high temperature and humidity, good development can be achieved over a long period of time. can be ensured.

[Brief explanation of drawings]

FIG. 1 shows a cross-sectional view of a developing device and an image device using the developing device according to an embodiment of the present invention. FIG. 2 shows a longitudinal sectional view of the developing device of FIG. 1. FIG. 3 shows a sectional view of a developing device according to another embodiment of the present invention. Brief explanation of symbols 201 Image carrier 12...Developer holding member 11...Hairy cleaning member 16...φ hole electrode member, '' Fig. 1

Claims (1)

[Scope of Claims] A developer holding member that holds a developer containing non-magnetic toner capable of retaining a charge and magnetic carrier particles having a particle size larger than that of the toner, and an external surface of the developer holding member that is rubbed against the developer. a perforated electrode member that is provided so as to be endlessly movable, has a large number of openings larger than the particle size of the toner particles and smaller than the carrier particles, and allows only the toner particles to be deposited to the outside by rubbing against the developer; a means for adhering the deposited toner particles to the latent image while keeping the perforated electrode plate and the image bearing member to be developed in non-contact; and a hair-like cleaning member that contacts the outside of the perforated electrode plate. A developing device characterized by: