JPH09244506A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately prevent aggregation of toner around a carrying screw in a carrying pipe and to always stably maintain an excellent carrying function by disposing a member abutting on the inner wall surface of the carrying pipe on the outer periphery of the carrying screw. SOLUTION: The basic constitution of an entire toner recycling means for carrying toner recovered from a cleaner to a hopper through the carrying pipe and a foreign matter separation device does not differ from the conventional one. In the carrying pipe 6, a brush 9 is arranged along the outer periphery of the spiral fin of the carrying screw 7 arranged inside so that its tip may abut on the inner peripheral surface of the pipe 6. By such constitution, the toner which is being carried is advantageously prevented from retaining in a gap part between the outer periphery of the screw 7 and the inner wall surface of the pipe 6. Then, faulty carrying and the lowering of a separation function caused by the retaining of the toner at this part are surely prevented.

Description

Detailed Description of the Invention

[0001]

[Object of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrostatic copying machine and a printer.

[0002]

2. Description of the Related Art In the known image forming apparatus as described above, when the toner image formed on the image carrier is transferred to a transfer material such as paper in the image forming operation,
It is inevitable that some transfer residual toner remains on the image carrier. Therefore, in order to continuously perform the image forming operation, it is necessary to sufficiently remove the residual toner generated at each transfer. Therefore, after the transfer process is completed, the residual toner is removed by the cleaner. This is as is well known.

By the way, the used toner, which appears every time one hard copy is obtained, becomes a considerable amount when a large number of copies are made.
It has already been proposed to return this to the developing device side and use it again for development. At the same time, however, the used toner is usually mixed with various foreign substances such as dust, paper powder, and toner solidified in a lump, so that it cannot be used again for development.

Therefore, in order to reuse the toner, it is necessary to remove the above-mentioned foreign substances mixed in the toner once collected by the cleaner from the image carrier and then supply the toner to the developing device side. Hereinafter, an example of an image forming apparatus that intends to reuse toner will be briefly described with reference to FIG.

FIG. 4 is a schematic main sectional view of a main part of such an image forming apparatus. The image signal L formed by the image signal forming portion 1 on the upper part of the apparatus main body is disposed inside the apparatus main body, and the precharged surface of the rotating cylindrical image carrier 2 having an axis line in the direction perpendicular to the paper surface. And is projected on to form an electrostatic latent image.

When the latent image reaches the developing portion where the developing device 3 having the hopper 4 is arranged as the image carrier 2 rotates, toner is supplied from the developing device to the latent image as a toner image. To be visualized. When this toner image reaches the transfer portion where the transfer means is arranged opposite to the image carrier 2, the transfer material such as paper is supplied to the transfer portion by this time.
The toner image on the image carrier side is transferred to the transfer material. The transfer material carrying the toner image is conveyed away from the image carrier to the fixing device 33, where the toner image is fixed and fixed on the transfer material.
It shall be discharged outside the aircraft.

A part of the toner which has not been transferred to the transfer material at the time of transfer is scraped off and collected by the cleaner 5, and is returned to the hopper 4 by a means described later. FIG. 5 is a rear view of the above-mentioned image forming apparatus, and shows means for returning the toner collected by the cleaner 5 to the hopper 4.

The toner collected in the cleaner 5 is discharged from the cleaner 5 by an appropriate conveying means such as a conveying screw, conveyed by a conveying pipe 6 having a conveying screw therein, and separated to remove the above-mentioned foreign matters mixed in the toner. It shall be replenished to the hopper 4 via the device 12.
This recycled toner is preferably used by appropriately mixing it with fresh toner separately supplied to the hopper 4. Reference numeral 13 in the figure is a collection box for storing the foreign matter separated and collected from the toner.

FIG. 6 is a sectional view of a portion indicated by reference character A in FIG. As shown in the figure, a conveying screw 7 is arranged in the conveying pipe 6, and the toner discharged from the cleaner 5 is combined with the attraction action of the magnet 8 arranged along the pipe 6 to move the toner upward. To do.

FIG. 7 is a sectional view schematically showing the structure of the separating device 12 shown by the symbol B in FIG. The separating device 12 is separated into two chambers, an upper chamber and a lower chamber, by a mesh 16, and the mesh 16 is struck and vibrated by a cam 15 attached to a motor 14 arranged in the upper chamber.

Further, the upper chamber is provided with an upper sleeve 19 in which a magnet of approximately 1000 gauss is housed and which is driven to rotate. The lower chamber has a magnet of approximately 650 gauss so as to sandwich the mesh 16. A lower sleeve 18 which is rotatably driven by being installed therein is arranged to face the upper sleeve.

The toner guided from the pipe 6 to the lower chamber by the conveying screw 7 and the toner conveying sleeve 17 is coat-conveyed to the lower sleeve 18 and is brought close to the mesh 16, and then sucked by the upper sleeve 19 and Transfer to. At this time, the foreign matter contained in the toner is filtered by the mesh 16, falls due to the vibration of the mesh, and falls again to the lower sleeve 18 side.

The toner that has been adsorbed by the upper sleeve 19 and the foreign matter has been removed is scraped off by the scraper 20 and conveyed to the hopper 4 through the dropping screw 21. Further, the foreign matter that has fallen onto the lower sleeve 18 is collected in the collecting box 13 via the foreign matter collecting sleeve 22.

FIG. 8 is a sectional view showing the developing device 3 mounted in the image forming apparatus and the hopper 4 for supplying toner to the developing device 3. The hopper 4 is replenished with new toner 23 from its upper opening, and regenerated toner is replenished from the dropping screw 21 in the manner described above. These toners are agitated by agitating rods 25 and 26 to be uniformly leveled as a whole, and then replenished to the developing device 3 by a hopper screw 27 as needed.

The toner supplied to the developing device 3 is agitated by the agitating wires 31 and 32, and is applied to the latent image formed on the surface of the image carrier (not shown) by the doctor blade 29 coating the surface of the developing sleeve 28. Shall be done. In the figure, reference numeral 30 is a sensor for detecting the amount of toner in the developing device.

By providing such a used toner collecting means, the toner utilization yield of about 90% is usually increased to about 99%, and a certain effect is recognized in the running cost reduction and the waste toner amount reduction. .

At the same time, however, in such a toner collecting means, the toner collected in the cleaner has to be conveyed to the hopper located above the cleaner against gravity due to the structure of the image forming apparatus. Particularly in a high humidity environment where toner is likely to condense, as shown in FIG. 9, the toner agglomerates and solidifies between the inner wall surface of the pipe 6 and the outer periphery of the conveying screw, and this is missing to prevent rotation of the conveying screw and convey the toner. There have been problems that various defects such as defects are caused and the function of the mesh is deteriorated by reaching the separating device.

The present invention has been made in order to cope with such a situation, and as described above, the toner regeneration provided with the conveying pipe having the conveying screw for conveying the toner collected from the cleaner to the foreign matter separating device. In an image forming apparatus equipped with a means, a toner regenerating means capable of suitably preventing the aggregation of toner around the carrying screw in the carrying pipe and maintaining a stable and good carrying function at all times, and an image forming apparatus equipped with the same. It is intended to be provided.

[0019]

Configuration of the Invention

In order to achieve the above object, the present invention is a means for conveying used toner discharged from a cleaner to a hopper on the developing device side by a conveying pipe having a conveying screw. An image forming apparatus comprising: an image forming apparatus (1), characterized in that a member that comes into contact with an inner wall surface of a conveying pipe is provided on an outer periphery of the conveying screw;
In the image forming apparatus (2) or the above (1), the member that comes into contact with the inner wall surface of the conveying pipe is a brush member provided on at least a part of the outer periphery of the spiral fin of the conveying screw. The image forming apparatus (3) is characterized in that the member abutting on the inner wall surface of the conveying pipe is made of an elastic rubber material at least a portion of the spiral fin of the conveying screw abutting on the inner wall surface of the conveying pipe.

With this structure, during the toner transportation by the transportation pipe, the toner is effectively prevented from staying in the gap portion between the inner wall surface of the pipe and the outer periphery of the transportation screw, and the occurrence of the transportation failure is avoided. be able to.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view showing a part of a carrying pipe for carrying the toner collected from a cleaner to a foreign matter separating device, showing an embodiment of the present invention. The basic structure of the entire toner regenerating means for conveying the toner collected from the cleaner to the hopper through the conveying pipe and the foreign matter separating device is not particularly different from that shown in the above-mentioned "FIG. 4" to "FIG. 7". Parts of FIG. 1 ”corresponding to those of the above-mentioned toner regenerating unit are designated by the same reference numerals (the same applies to the embodiment apparatus described later), and description thereof will be omitted.

In the illustrated conveying pipe 6, a brush 9 is arranged along the outer circumference of the spiral fin of the conveying screw 7 arranged inside so that the tip of the brush 9 contacts the inner wall surface of the pipe 6. is there.

With this structure, it is possible to effectively prevent the toner during transportation from staying in the gap between the outer periphery of the transport screw 7 and the inner wall surface of the pipe 6, and the toner is retained and solidified in this portion. It is possible to surely prevent the conveyance failure, the deterioration of the separation function, and the like due to the above.

FIG. 2 is a sectional view of a portion of the carrier pipe showing another embodiment. In this apparatus, at least the tip portion of the spiral fin of the carrying screw 10 arranged in the carrying pipe 6 and the portion that comes into contact with the inner wall of the pipe 6 are made of a flexible rubber agent.

With this structure, it becomes possible to prevent the toner from staying and adhering to the inner wall surface of the pipe, as in the apparatus of the above embodiment.

[FIG. 3] FIG. 3 is a sectional view of a portion of a transport pipe showing still another embodiment. In this apparatus, a brush 11 that contacts the inner wall surface of the pipe is formed on a part of the outer circumference of the spiral fin of the conveying screw 7.

With this structure, toner is prevented from staying in the gap between the inner wall surface of the pipe 6 and the outer periphery of the conveying screw, as in each of the above-described embodiments, so that the toner stays. You can avoid the problem.

[0028]

As described above, according to the present invention,
In an image forming apparatus equipped with a toner regenerating unit configured to convey the used toner collected from the cleaner upward and to recirculate it to the hopper on the developing device side, a conveying screw for conveying the toner from the cleaner toward the hopper is internally provided. The toner being conveyed can effectively be prevented from staying and solidifying in the gap between the inner wall surface of the pipe and the outer circumference of the conveying screw. Effectively avoiding deterioration of the function of removing foreign matter mixed in, it is possible to always stably convey good used toner, and it is possible to recycle high-quality regenerated toner to the hopper, thus improving toner utilization efficiency. Improvement,
It has a remarkable effect on maintaining good image quality.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a conveying pipe that conveys toner discharged from a cleaner to a hopper, showing an embodiment of the present invention.

FIG. 2 is a sectional view of a carrier pipe showing another embodiment.

FIG. 3 is a sectional view of a carrier pipe showing still another embodiment.

FIG. 4 is a schematic principal surface view showing the configuration of a known image forming apparatus.

FIG. 5 is a rear view showing the toner regenerating unit of the same.

FIG. 6 is a cross-sectional view showing a configuration of a portion A of FIG.

FIG. 7 is a cross-sectional view showing a configuration of a portion B of “FIG. 5”.

FIG. 8 is a cross-sectional view showing a configuration of a developing device and a hopper of the image forming apparatus.

FIG. 9 is an explanatory diagram showing a state in which toner is accumulated during transportation in a known pipe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image signal imparting means 2 Image carrier 3 Developing device 4 Hopper 5 Cleaner 6 Conveying pipe 7, 10 Conveying screw 8 Magnet 9, 11 Brush 12 Separating device 13 Foreign matter collection box 14 Motor 15 Cam 16 Mesh 17 Toner conveying sleeve 18 Lower sleeve 19 Upper sleeve 20 Scraper 21 Drop screw 25, 26 Stirring rod 31, 32 Stirring wire 28 Developing sleeve

Claims (3)

[Claims] 1. An image forming apparatus comprising means for conveying used toner discharged from a cleaner to a hopper on a developing device side by means of a conveying pipe having a conveying screw inside, and an inner wall surface of the conveying pipe on an outer periphery of the conveying screw. An image forming apparatus comprising a member that comes into contact with the image forming apparatus. 2. The image forming apparatus according to claim 1, wherein the member contacting the inner wall surface of the conveying pipe is a brush member provided on at least a part of the outer periphery of the spiral fin of the conveying screw. 3. The "claim 1" according to claim 1, characterized in that the member abutting on the inner wall surface of the carrying pipe is made of an elastic rubber material at least a portion of the spiral fin of the carrying screw which abuts on the inner wall surface of the carrying pipe. Image forming device.