JPH01161273A - Toner dispersion preventing member for developing device - Google Patents

Abstract

PURPOSE:To recover toner into a developing device and to prevent toner from being escaped from a gap of an opening part by positioning the tip part of a conductive magnetic seal member arranged on the gap part between the edge part of the opening part to an image carrier and a rotating sleeve, on a part where the sleeve is close to the developing device. CONSTITUTION:The opening part 6 is formed on the side where the developing device 2 is opposed to a photosensitive body 1 and a magnet roll 3 and the rotating sleeve 4 surrounding the roll 3 are arranged on the opening part 6. On the other hand, a seal member 5 having proper elasticity is arranged on a gap part opposed to the side of a napping cutting blade 8 on the opening part 6 of the developing device 2 and the tip part of the seal member 5 is positioned between adjacent magnetic poles formed on a magnet 3 in a gap part 7 on which the sleeve 4 is most close to the developing device 2. Consequently, the escape of the toner in the developing device can be surely prevented and toner left on the surface of the sleeve 4 after developing can be surely recovered into the developing device.

Description

Detailed Description of the Invention (1) Purpose of the Invention (Field of Industrial Application) This invention relates to image forming apparatuses that utilize an electrostatic recording process, such as electrostatic copying machines and printers, and in particular, toner scattering in their developing devices. This invention relates to a prevention member.

(Prior Art and Problems to be Solved) A known image forming apparatus includes a step of forming an electrostatic latent image on a photosensitive layer on the surface of an image carrier and supplying toner to turn the latent image into a visible toner image. In order to supply toner to the latent image on the surface of the image bearing member, a developing device containing the toner and having an opening facing the image bearing member is disposed, and a magnetic roller is placed in the opening and a developing device surrounding the developing device is provided. There is a wide variety of devices in which a sleeve is provided and the sleeve is rotated so that the toner adsorbed to the sleeve surface by the action of a magnetic roller is electrostatically attached to the latent image on the surface of the image carrier through the opening. It is put into practical use.

In such a device, since a movable sleeve carrying toner is disposed in the aforementioned opening, it is practically impossible to completely seal this part, and it is impossible to completely seal the part. There is a risk that toner may leak.

In order to avoid such inconveniences, a configuration as shown in FIG. 4, for example, has been proposed in the past.

To briefly explain this, a developing device 11 is disposed in close proximity to a cylindrical photoreceptor 10, only a portion of which is shown, that extends perpendicular to the plane of the paper and rotates in the direction of arrow X.
The opening 15 faces the photoreceptor.

A magnet 12 and a sleeve 13 surrounding the magnet 12 are disposed in this opening, and the sleeve is rotated in the direction of arrow Y by an appropriate drive source (not shown).

The toner stored in the developing device is charged by stirring or the like by an appropriate means, and the toner is charged by a magnetic roller 12.
The sleeve 13 is attracted to the surface of the sleeve 13 by the action of the sleeve 13, and by this rotation, it is sequentially conveyed in the direction of the opening 15, and its amount is controlled by the ear cutting blade 14, so that it approaches the surface of the image carrier and becomes an electrostatic latent image. It adheres to form a visible toner image.

Then, the toner remaining on the sleeve without contributing to development returns to the developing device as the sleeve rotates.

In such a device, as shown in FIG. 4, a toner scattering prevention ζ1 made of FEP, urethane, mylar sheet, etc. is provided in the gap part of the opening 15, especially on the side where excess toner is collected again into the developing device. - River seal member 16
It has been proposed to prevent toner from escaping.

Although such means can be expected to have a certain effect as long as the sealing member maintains a predetermined shape and elasticity, due to the pressure of toner in the developing device or long-term use, it may cause damage as shown by the dotted line in the figure. However, it was not free from the drawback that it deformed in a state close to plastic deformation, leading to functional deterioration.

Furthermore, in order to avoid the above-mentioned drawbacks, if the sealing member 16' is formed to be long as shown schematically in FIG. This may cause local uneven adhesion of the toner on the sleeve, or the sealing member may cover the area where the toner is applied on the sleeve, preventing the toner on the sleeve from returning to the developing device and causing it to leak outside. The problem of escape arises.

The present invention has been made in order to deal with such problems in front of a vehicle, and it is a developing device equipped with a rotating sleeve, in which developed toner is collected into the developing device from an opening facing the sleeve. It is an object of the present invention to provide a developing device that can effectively prevent the toner from escaping from the opening gap.

(2) Structure of the invention (technical means for solving the problem, its operation) In order to achieve the above object, the present invention has an opening facing the image carrier, and a magnet roller and a magnet roller are installed in the opening. In a developing device including a surrounding rotating sleeve, a tip of a conductive magnetic sealing member disposed in a gap between an edge of the opening and the sleeve is positioned between adjacent poles around the magnet roller. In a developing device, the developing device has an opening facing the image carrier, and the opening is provided with a magnet roller and a rotating sleeve surrounding the magnet roller.
The apparatus is characterized in that the tip of a conductive magnetic sealing member disposed in a gap between the edge of the opening and the sleeve is positioned at a portion where the sleeve and the developer casing are close to each other. .

With this configuration, it is possible to reliably prevent the car from escaping within the developing device, and to reliably recover the toner remaining on the sleeve surface after development into the developing device.

(Description of Embodiments) FIG. 1 is a side view of essential parts of an embodiment in which a developing device according to the present invention is applied to a copying machine equipped with a rotating cylindrical photoreceptor.

A developing device 2 is arranged close to and parallel to a photoreceptor 1 extending perpendicularly to the plane of the paper and rotating in the direction of arrow A.

An opening 6 is formed on the side facing the photoreceptor 1 of the developer casing, and a magnet roller 3 is inserted into this portion.
A sleeve 4, which is rotated by an appropriate drive source (not shown), is disposed surrounding this.

With this structure, the toner stored in the developing device is attached to the sleeve 4 by the action of the magnet 3, and as the sleeve rotates, it is conveyed counterclockwise in the figure, and the toner is cut into ears by the ear cutting blade 8. After the is adjusted,
It is assumed that the toner is transferred to the photoreceptor by coming into contact with or in close proximity to the electrostatic latent image on the surface of the photoreceptor 1, and the latent image is developed.

As is well known, around the photoreceptor there is a negative charger,
It goes without saying that an image signal applying means, a transfer charger, a cleaning device, and other members necessary for forming fine images are provided, but since they are not directly related to the present invention, they are all omitted.

In the developing device 2 as described above, a sealing member 5 having appropriate elasticity is disposed in the gap between the opening and the side opposite to the side where the ear cutting blade 8 is located, and the tip thereof is , so that the sleeve is located closest to the developer casing, at the gap indicated by 7, and between adjacent magnetic poles formed on the magnet 3.

In the illustrated example, the seal member is TDK
Company-made % inch videotape KCS series (product name)
It was used.

As shown in FIG. 2, this tape consists of a reinforced polyester base 51 with a thickness of 20 l, a magnetic layer 53 with a thickness of 4.5 p,
The opposite surface 52 has a surface resistivity of 5×105Ω/sq.
The conductive layer has a thickness of 1.5 mm and is arranged so that this surface faces the sleeve.

The magnetic material used for the magnetic layer was Abilyn (trade name), which had a coercive force of 6800e and a maximum residual magnetic flux density of 1320 Gauss. In addition, the yield point load of this tape is 5.5 kg,
The breaking strength was 10.5 kg, and the surface electrical resistance of this magnetic layer was 1xlO9Ω/sq.

Since the sealing member is arranged as described above, the sealing member 5 tends to be attracted to the surface of the sleeve 4 as it is used, thereby preventing the toner inside the developing device from escaping to the outside. Therefore, toner that does not contribute to development and returns into the developing device as the sleeve rotates can be smoothly passed through.

In addition, since the conductive layer of the seal member 5 has a low resistance, when toner tribo unevenness occurs, the tribo leaks through this seal member and equalizes the leakage, thereby preventing the occurrence of image unevenness. can be played.

The surface resistance value of this conductive layer was determined by experiment to be 103 to 1.
It was found that a range of approximately 0.07Ω/sq is sufficient.

At this time, if the free end of the seal member is in a position facing the pole of the magnet, the member is strongly attracted to the sleeve, which is convenient for preventing toner from escaping, but when guiding the toner into the toner developer. This is not preferable because the sealing member acts like a scraper and may cause the toner to escape to the outside.

The other end of the sealing material shall be adhered to the bottom of the developer at a suitable location using double-sided tape or adhesive.

FIG. 3 shows another embodiment of the present invention, in which parts corresponding to those shown in FIG. is omitted.

In this developing device, the sealing member 5 is disposed in the counter direction with respect to the sleeve 4.

It will be readily understood that even in such a configuration, the sealing member is conductive and tends to be attracted to the sleeve, so that the same effect as in the above embodiment is produced.

However, in this case, in order to prevent the sealing member from acting as a scraper on the toner after development, it is preferable to extend its free end slightly so that its edge separates from the sleeve. be.

In addition to the above-mentioned sealing members, TDK's KCA
Series HCP-3NT, AD-LP series; D
, AD, AR, AR-X, etc., and is not limited to these, and it goes without saying that any device that meets the requirements described above can be used.

Furthermore, as a sealing member, it is not limited to the one with the three-layer structure as described above, but a magnetic layer on one side of the base film,
It is also possible to control the surface resistance to about 10 5 Ω/sq and use the surface in contact with the photoreceptor.

Furthermore, although the present invention has been described above in the case where it is applied to a copying machine, it goes without saying that the present invention is not limited to this and can be applied to other image forming apparatuses, printers, and the like.

(3) Effects of the Invention As explained above, the present invention performs a sealing action by the tendency of the sealing member to attract the developing/image sleeve, and at this time, by positioning the free end of the sealing member between the poles of the magnetic roller, Compared to a sealing member that uses the stiffness of the sealing member itself to seal, the pressing force against the sleeve can be weakened, making it possible to reliably collect the developed toner into the developing device and to prevent the developing toner from developing. Since it does not weaken the effect of preventing toner from escaping inside the developing device, overall it prevents contamination of various parts due to toner escaping from the developing device, as well as image deterioration caused by this, and produces high-quality images. It is effective for obtaining

Furthermore, even if there is some waviness in the sealing member, this is compensated for by the magnetic adsorption effect, and toner sealing is performed effectively. It is effective in preventing the occurrence of

Furthermore, by arranging the free end of the seal member in a position where the sleeve and the developer casing are close to each other in the developing device, the swinging of the free end portion of the seal member can be suppressed as much as possible. This is effective in increasing its durability.

[Brief explanation of the drawing]

FIG. 1 is a side view of essential parts showing an embodiment in which the present invention is applied to a copying machine, FIG. 2 is an enlarged sectional view showing the configuration of a seal member, and FIG. 3 is a main part showing another embodiment of the present invention. Side View FIGS. 4 and 5 are side views showing the operation of a known developing device. l... Photoconductor, 2... Developing device, 3... Magnet, 4... Life/developing sleeve, 5... Seal member, 6...
·Aperture. Figure 1 Figure 2 Figure 4 Figure 5... 11th 3rd
Figure ■″”]1? -1μ゛

Claims (3)

[Claims] (1) In a developing device such as an electrophotographic copying machine that holds toner on a toner carrier and develops a latent image on an image holding member, a sheet material coated with or impregnated with a magnetic material is used to prevent toner from scattering. A toner scattering prevention member characterized in that it is used in contact with a lower part of a toner carrier. (2) The toner scattering prevention member according to claim 1, wherein the contact position of the sheet material below the toner carrier is the closest point between the toner carrier and the inner wall of the developing device. (3) The position of the sheet member in contact with the lower part of the toner carrier is
The toner scattering prevention member according to claim 1 or 2, which is located between the magnetic poles of the internal magnet of the toner carrier.