JPS6362745B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic powder removal device using a cylindrical magnet roll having a plurality of magnetic poles on its surface.

As one of the dry copying methods, an electrostatic latent image formed on the surface of a material layer is developed using a magnetic developer, and then the developed image is transferred onto a transfer member such as general paper and fixed. Methods of obtaining copy images are known. In this copying method, a corona discharger or a conductive rubber roller is generally used as the transfer method, but no matter what transfer method, the transfer efficiency cannot be 100%, and there will be some untransferred parts. of magnetic developer remains on the surface of the electrostatic latent image carrier. As a device for removing these residual developers, a magnetic brush cleaning device is known, which uses a permanent magnet roll having a substantially internal cross section inside a non-magnetic cylindrical sleeve. Photoreceptor cleaning devices are known that combine a roll with a fur brush, a porous elastic roll, a blade member, or the like. By the way, instead of using the sleeved magnet roll as described above, it is also conceivable to adsorb and convey the magnetic developer directly onto the surface of the above-mentioned magnet roll. According to this method, since a sleeve is not required, the structure of the cleaning device can be simplified and an inexpensive device can be obtained. However, when only a magnet roll is used, unlike when a sleeved magnet roll is used, it is extremely difficult to easily remove the magnetic developer strongly adhered to the surface of the magnet roll.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the problems of the conventional techniques as described above, and to provide a magnetic powder removal device that can easily and reliably remove magnetic powder strongly adhered to the surface of a magnet roll.

The details of the present invention will be explained below with reference to the drawings. In the examples described below, a case will be described in which magnetic toner is used as the magnetic powder.

FIG. 1 is a sectional view of a main part showing an embodiment of the present invention, and FIG. 2 is a perspective view of FIG. 1. A cylindrical magnet roll 1 having a plurality of magnetic poles rotates in the direction indicated by the arrow x in the figure. The damming member 2 is installed so that its tip end is close to or in contact with the surface of the magnet roll 1 in the longitudinal direction, and in this embodiment, a case where the tip end is in contact with the surface of the magnet roll 1 is shown. The damming member 2 is located approximately on a tangent to the magnet roll 1 from the tip thereof, and is arranged in the rotational direction of the magnet roll 1. A part of the collection member 3 contacts at least the vicinity of the tip of the damming member 2 and forms a relatively dense opening with the tip of the damming member 2 at a predetermined interval in the longitudinal direction as shown in FIG. It will be installed like this. In FIG. 2, the collecting member 3 has an opening, but it may also be a member having an uneven portion at its tip. In the above configuration, when the magnetic toner 4 adheres to the surface of the magnet roll 1 and is conveyed as the magnet roll 1 rotates in the direction of the arrow x shown in the figure, the magnetic toner 4 is prevented from moving by the damming member 2 and the magnetic toner 4 accumulates in the magnetic toner pool 41. form. However, this magnetic toner pool 41 overflows into the opening of the collection member 3 formed between the tip of the damming member 2 and the top of the collection member 3 due to the rotating magnetic field caused by the rotation of the magnet roll 1 in the direction of the arrow x in the figure. A conveying force is generated in the direction of the arrow y shown in the figure, and the particles fall into the collection tank 5. If the collecting member 3 is not present, the magnetic toner 4 cannot be easily collected from the surface of the magnet roll 1 in this way. The materials of the damming member 2 and the collection member are preferably elastic, such as rubber, polyester plate, phosphor bronze plate, etc. Further, these members are not limited to the above-mentioned non-magnetic materials, but may also be made of magnetic materials. Further, the dam member 2 and the collection member 3 may be integrated. The method for attaching the damming member 2 and the collection member 3 is arbitrary and not shown.

Figure 3 uses magnetic toner to which the present invention is applied.
FIG. 2 is a cross-sectional view showing an example of a photoconductor cleaning device for a PPC subject. The magnetic toners 4 and 2 remaining on the surface of the photoreceptor 5 after the transfer process are scraped off by the cleaning blade 7 and attracted to the magnet roll 1.
The attracted magnetic toner 4 is dammed up by the damming member 2 to form a magnetic toner pool 41, but is immediately led to the collection tank 5 by the collection member 3.

As described above, according to the present invention, the magnetic toner strongly attracted to the surface of the magnet roll can be easily and reliably removed. Therefore, it can be applied to various photoreceptor cleaners in place of the conventional sleeved magnet roll. Therefore, according to the present invention, the structure of the cleaning device can be simplified and the cost can be reduced. In addition to the blade 5 shown in FIG. 3, specific application examples of the apparatus of the present invention include cleaning apparatuses using fur brushes and porous elastic rolls, and furthermore, magnetic brush cleaning apparatuses. Furthermore, the present invention is applicable not only to magnetic toner but also to devices for adsorption and removal of all kinds of magnetic developers in electrophotography, as well as devices for adsorption and removal and collection of other elastic powders.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of the main part of the magnetic powder removing device according to the present invention, Fig. 2 is a perspective view showing an example of attachment of a damming member and a collection member, and Fig. 3 is an application of the magnetic powder removing device according to the present invention. FIG. 2 is a sectional view of a main part of a photoreceptor cleaning device showing an example. 1: Magnet roll, 2: Damping member, 3: Collection member, 4: Magnetic toner.

Claims (1)

[Claims] 1 Rotates in a predetermined direction and has multiple magnetic poles,
A device for removing magnetic powder adsorbed to the surface of a magnet roll having a substantially circular cross section, wherein the tip portion is moved approximately on a tangent to the surface of the magnet roll so that the tip portion contacts or approaches the longitudinal direction of the surface of the magnet roll. A relatively dense opening is formed at a predetermined interval between the magnetic toner damming member installed in the rotation direction of the magnet roll and the tip of the damming member by overlapping at least near the tip of the damming member. 1. A magnetic powder removal device comprising: a magnetic toner collection plate installed so as to have a magnetic toner collection plate;