JPS63281179A - Toner replenishing device for two-component developing device - Google Patents

Abstract

PURPOSE:To contrive to surely execute sealing and to equalize a toner replenishment by always sealing a replenishing opening of a toner replenishing device, by a magnetic brush formed by a replaced developer. CONSTITUTION:A part of a developer which flows circularly toward a paddle wheel through on a separator 7 is adsorbed by a magnet roller 13 and a magnetic brush is formed on its surface. Right under the magnet roller 13, a replenishing blade 14 is provided so that its upper end comes to a position separated from the surface of the magnet roller by a shorter distance than length of a tuft of the magnetic brush, and also, a toner replenishing opening 12 is set to width sealed by the magnetic brush. Accordingly, the toner replenishing opening is always sealed by the magnetic brush, and it is prevented that a toner in the toner replenishing part drops unnecessarily into a developing device 1. In such a way, the time aging of the sealing property of the toner replenishing opening 12 and the toner replenishing performance is eliminated.

Description

[Detailed description of the invention] Technical field The present invention relates to a toner replenishing device for a two-component developing device.

Prior Art In a developing device of an electrostatic recording device such as an electrophotographic copying machine, which develops an electrostatic latent image formed on a photoreceptor using a two-component developer consisting of a carrier and a toner, as the number of sheets to be developed increases, the amount of developer increases. As the toner in the developer is consumed and the toner concentration decreases, toner is replenished every time a predetermined number of sheets are developed or each time the toner concentration of the developer in the developer drops below a predetermined value. is maintained within a predetermined range.

FIG. 4 shows an example of a conventional dry type two-component developing device, in which a developing roller 3 having a magnet inside is provided in a developing device 1 at a predetermined developing gap from a photosensitive drum 2. . A paddle wheel 4 is provided in the developer reservoir in the developing device 1, and as the paddle wheel 4 rotates, the developer 5 in the developer reservoir is supplied to the circumferential surface of the developing roller 6, and the developer 5 in the developer reservoir is supplied to the circumferential surface of the developing roller 6 due to the magnetic force of the internal magnet. As the developing roller 3 rotates in the direction of the arrow, the developing roller 3 is conveyed toward the developing position where it contacts the photosensitive drum 2, and on the way, it is opposed to the developing roller 6 with a predetermined gap therebetween. doctor blade 6
The layer thickness is regulated, and a constant amount is supplied to the developing section.
Excess developer is returned onto the paddle wheel 4 via the upper surface of the separator 7. A replenishment opening 12 of the toner replenishing device 9 opens further rearward of the rear end 8 of the separator and above the paddle wheel 4, and means for replenishing a fixed amount of toner is provided in this portion.

A conventional toner replenishment means includes a grooved roller 10 having a plurality of grooves extending in the axial direction on its surface, and sponges 11 provided on both sides of the grooved roller so as to bite into the grooves. On the side where the edge of the sponge is in the trailing direction with respect to the rotation direction, the toner in the toner supply device 9 passes through the sponge while remaining in the groove of the grooved roller 10, and on the leading side, the edge of the sponge is in the grooved roller 10. At that time, the toner in the groove is flicked off by the sponge and falls onto the paddle wheel 4 in the developing device 1, where it is combined with the developer that has returned on the separator 7. transported and stirred.

However, with this toner replenishing means, the sponge deforms over time, toner accumulates on the sponge and becomes hard, changing the toner replenishment performance, and toner adheres to the grooves of the grooved roller 10. It has the disadvantage of solidifying and reducing the supply amount.

Instead of a sponge, leaf springs with curved tips are placed in contact with both sides of the grooved roller. In this case, it prevents deterioration over time like a sponge, but toner still accumulates in the grooves. They are similar in that they coagulate and solidify, and they also have the disadvantage that it is difficult to replenish toner uniformly in the width direction.

Furthermore, in these conventional toner replenishment methods, toner is directly replenished into the developing device, so toner may float inside the developing device, or the developer and toner may get mixed up, or the toner and carrier may become mixed. Problems such as development being performed without sufficient agitation tend to occur particularly in high-speed machines or when a large amount of toner is replenished.

Purpose: In view of the above-mentioned drawbacks of developing devices for electrostatic recording devices such as electrophotographic copying machines that use conventional two-component developers, the present invention provides a system that eliminates changes over time in the sealing performance of toner replenishment openings and toner replenishment performance. It is an object of the present invention to provide a toner replenishing device for a two-component developing device, which provides uniformity in the amount of toner replenishment in the width direction and prevents separation of the replenished toner and developer.

Structure: In order to achieve the above object, the toner replenishing device of the present invention is located at a position opposite to the path of the developer circulating in the developing device and sufficient to adsorb the developer circulating in the path. A magnetic roller is provided at the opening of the toner replenishing section, and a magnetic brush formed by a developer is installed on the magnetic roller to seal the opening of the toner replenishing section. A feature is that a replenishment blade is provided in close proximity to the magnetic brush so that it can scrape off the ears of the magnetic brush.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of a two-component developing device equipped with a toner replenishing device according to the present invention. In the figure, members having the same functions as those of the conventional developing device previously explained in FIG. 4 are designated by the same reference numerals, and repeated explanation will be omitted.

In the figure, a magnet roller 13 having a magnet inside is provided in a replenishing opening 12 of the toner replenishing section 9 so as to be rotatable in the direction shown by the arrow. The gap between the flow of the developer circulating in the path of the developer returning to the paddle wheel 4 via the upper surface of the separator 7 and the surface of the magnet roller 16 is determined by the magnetic force of the developer circulating in the path being applied to the magnet roller 13. The interval is such that the developer is sufficiently attracted, and a portion of the developer flowing back toward the paddle wheel via the separator 7 is attracted to the magnetic roller 13, forming a magnetic brush on its surface.

A replenishment blade 14 is provided directly below the magnet roller 16 so that its upper end is spaced apart from the surface of the magnet roller by a distance shorter than the length of the ear of the magnetic brush. Further, the toner supply opening 12 has a width that can be sealed by the magnetic brush.

Therefore, the toner supply opening is always sealed by the magnetic brush, and the toner in the toner supply section is prevented from unnecessarily falling into the developing device 1. When the magnetic roller 13 rotates in the direction of the arrow in response to the toner replenishment signal, the toner in the toner replenishing unit 9 adheres to the ears of the magnetic brush formed on the surface of the magnetic roller 13 and rotates, interfering with the replenishing blade 14. The part of the toner that has been removed is scraped off, and the recycled developer and new toner fall near the C dollar wheel 4 in a mixed state.

The diameter, rotation direction, magnetic force, and distance between the circumferential surface of the toner replenishing magnetic roller 13 and the casing and replenishment blade tip of the toner replenishing section 9 are determined as appropriate depending on the layout of the device, the amount of toner replenishment, etc. However, what is required is (a) that new developer is always supplied during the toner replenishment operation of the magnet roller 13, (b) that toner is reliably attached to the magnetic brush formed on the magnet roller, ( c) The spike of developer scraped off by the replenishment blade and containing new toner should be able to be supplied to the developer stirring section in the developing device main body.

As long as the above conditions are satisfied, various modifications can be made to the rotating direction of the magnetic roller, the shape and arrangement of the replenishing blade, etc.

In the embodiment shown in FIG. 2, the separator 7 extends rearward beyond the lower part of the toner supply port 12, and an opening 21 is provided in a portion of the separator 7 below the magnetic roller 13 over almost the entire width. The edge 22 is made to interfere with the magnetic brush formed on the surface of the magnet roller 13 by an appropriate amount, and is used as a replenishment blade.

Further, in the embodiment shown in FIG. 6, the casing of the toner replenishing section 9 is inserted into a magnetic brush formed on a magnet roller 13 that rotates counterclockwise at the rear edge 31 of the toner replenishing opening 12 to replenish the toner. It is made into a blade.

In the toner replenishment device explained in FIGS. 1 to 3, the amount of toner replenishment is determined by the amount of biting of the replenishment blade into the magnetic brush, that is, the length of the magnetic brush ears formed on the magnet roller, the surface of the magnet roller, and the replenishment blade. It is determined by the difference between the tip and the gap. Therefore, by making this gap variable, the amount of toner replenishment can be adjusted as desired.

Furthermore, by making this gap changeable in the width direction (axial direction of the magnet roller 13), when making a copy smaller than the full width, more toner can be supplied to areas that consume more toner than other areas. becomes possible.

In addition, the magnetic roller is formed by inserting the magnet removably into a non-magnetic sleeve, and when the magnet is removed from the sleeve, the magnetic force on the surface of the magnetic roller disappears and no magnetic brush is formed, making it easy to replenish toner. The opening is not sealed, and when loading developer into the developing device for the first time, the toner replenishing device 9 is used as a developer loading hopper, and the developer containing magnetic carrier is rapidly loaded into the developing device. Can be filled.

Further, the amount of toner replenishment can also be changed by varying the rotation angle of the magnet within the sleeve so that the position of the magnetic pole in the magnet roller 13 with respect to the replenishment blade is variable.

Effects According to the present invention, the replenishment opening of the toner replenishment device is sealed by a magnetic brush formed by the developer that is constantly replaced. The seal is reliable, and the lifespan is the same as that of the developer. Further, unlike toner replenishment using an elastic member and a groove in a roller, toner replenishment is performed by interfering with a magnetic brush using a replenishment blade, so that changes over time can be prevented.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing a developing device including an embodiment of the present invention, FIGS. 2 and 3 are side sectional views showing the vicinity of a toner replenishing section of another embodiment, and FIG. 4 is a conventional toner FIG. 2 is a side sectional view showing an example of a two-component developing device including a replenishing means. 1... Developing device 2... Photoreceptor 3... Developing roller 4... Paddle wheel 5... 2
Component developer 7... Separator 9-) Toner supply section 12... Toner supply means 16... Magnet roller 14... Supply blade 21... Opening 22 of the senor ξ plate 22-... Its edge 31. ...Rear edge of the opening of the toner replenishing section Fig. 1 Fig. 2 Fig. 3

Claims (1)

[Scope of Claims] (1) Two-component developer consisting of carrier and toner is circulated within the developing device, and the toner consumed during development is replenished from the opening of a toner supply unit connected to the developing device. In the toner replenishing device of the developing device, a magnetic roller is provided at the opening of the toner replenishing section at a position opposite to the path of the developer circulating in the developing device and at a position sufficient to adsorb the developer circulating in the path. Seal the opening of the toner replenishing section with a magnetic brush formed by a developer on a magnetic roller, and scrape off the ears of the magnetic brush in close proximity to the magnetic roller at a distance within the length of the ears of the magnetic brush. A toner replenishing device characterized by being provided with a replenishing blade that can be refilled. (2) Claim 1, wherein the replenishment blade is formed by the edge of an opening provided in a separator that circulates developer from a doctor blade provided along the developing sleeve. The toner supply device described in . (5) The toner replenishing device according to claim 1, wherein the replenishing blade is formed by an edge of a casing of the toner replenishing section. (4) Claim 1, characterized in that the gap between the tip of the replenishment blade and the magnet roller is adjustable.
The toner replenishing device described in section. (5) The toner replenishing device according to claim 1, wherein the magnet roller is formed by inserting a magnet into and out of a non-magnetic sleeve. (6) The toner replenishing device according to claim 1, wherein the magnet in the magnet roller is rotationally adjustable within the sleeve so that its position relative to the replenishing blade can be adjusted.