JPH0533795B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a magnetic brush developing device for a copying machine, and particularly relates to an improvement of a magnetic brush developing device that is compact and has stable copy density and copy image quality. be.

[Prior Art] As shown in FIG. 4, a conventional magnetic brush developing device for a copying machine includes a developing roller c and a developing roller c disposed in a developing device housing a and facing a photosensitive drum b of the copying machine. , a side surface e for guiding the developer d separated from the developing roller c after development to the lower side of the device housing a, and the developer d provided below the developing roller c and deposited at the lower part of the device housing a. A bucket wheel f pumps up the toner and supplies it to the developing roller c for reuse, and uniformly stirs the toner supplied from a toner replenishing section (not shown) and the developer d in the device housing a. A mixer g is provided for supplying the developer d from the developing roller c through the opening h of the device housing a toward the photosensitive drum b holding the electrostatic latent image to form the latent image. An apparatus for developing a visible image into a visible image is known.

Note that i in FIG. 4 indicates a spike adjustment plate for adjusting the magnetic brush of the developer d formed on the surface of the developing roller c to a constant length.

[Problems to be Solved by the Invention] However, in the conventional magnetic brush developing device, in addition to the developing roller c, the bucket wheel f and the mixer g are provided in the device housing a.
Since it is necessary to provide large members such as, the entire developing device becomes large and the cost is relatively high.

Particularly in color copying machines, since a plurality of developing devices are disposed around the photosensitive drum, the above-mentioned drawbacks become conspicuous, and there has been a desire for an inexpensive and compact magnetic brush developing device.

[Means for Solving the Problems] The present invention has been made by focusing on the above-mentioned problems, and its object is to create a small and inexpensive device that does not require bucket wheels, mixers, etc. An object of the present invention is to provide a magnetic brush developing device.

That is, the present invention provides a magnetic brush developing device for a copying machine, which is disposed opposite to a photoconductor of the copying machine, and in which a developing roller supplies developer toward the photoconductor holding an electrostatic latent image. is provided on the developing roller and the rear side of the developing roller, and conveys the developer scraped off by the spike adjustment plate of this roller to the first opening of the partition member provided on the lower side thereof. a first lower auger provided on the lower side of the partition member for supplying the developer that has fallen from the first opening to the developing roller; and a first lower auger provided on the lower side of the partition member At a position below a second opening opened opposite to the first opening, the toner supplied from the toner replenishing section is supplied to the developer conveyed by the first lower auger. This magnetic brush developing device for a copying machine is characterized in that it includes a second lower auger that conveys developer replenished with toner onto the partition member through a second opening.

[Effect] The present invention operates as follows.

That is, in place of the conventional bucket wheel and mixer, in the developing device of the present invention, the developer and the supplied toner are uniformly mixed by the upper auger, the first and the second lower augers provided below the partition member. , and the developer is supplied to the developing roller, the entire device can be made smaller and its cost can also be reduced.

Further, in this device, the toner supplied from the toner replenishing section is mixed into the developer conveyed by the first lower auger at a position below the second opening of the partition member, and is sufficiently supplied by the auger on the partition member. Because the toner is uniformly agitated and then supplied to the developing roller by the first lower auger through the first opening, the conveyance path from the toner replenishing section to the developing roller becomes long, which affects the charging characteristics of the toner. It is possible to maintain stable copy density and copy image quality over a long period of time.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.The magnetic brush developing device of the present invention includes a photosensitive drum 1 as shown in FIGS.
an apparatus housing 2 disposed near the housing 2; a developing roller 3 disposed within the housing 2 facing the photosensitive drum 1 and rotating in the same direction as the photosensitive drum 1; and a rear side of the developing roller 3. a receiving plate 6 which is a concave partition member provided along the length direction of the developing roller 3 and receives the developer 5 scraped off by the spike adjustment plate 4 of the developing roller 3;
An upper auger 7 and a first lower auger 8 are provided on the upper and lower sides of the first lower auger 8, respectively, and the first lower auger 8 is connected to one end of the first lower auger 8, and supplies toner to the developer 5 conveyed by the lower auger 8. a second lower auger 9 (see FIG. 2), and a toner replenishing section 10 disposed above the end of the second lower auger 9 and replenishing toner into the apparatus via the second lower auger 9. It is composed of.

First, as shown in FIG. 1, the developing roller 3 is made up of a rotating sleeve (not shown) that rotates in the same direction as the photosensitive drum 1, and a plurality of fixed magnets N and S built into the rotating sleeve. A first opening 11 and a second opening 12 are provided on both sides of the receiving plate 6 provided on the rear side of the developing roller 3.

On the other hand, the above upper auger 7 and the first lower auger 8
As shown in FIG. 2, the rotating shafts 13 and 14 are rotatably arranged by a drive source not shown, and the rotating shafts 13 and 14 are attached to the rotating shafts 13 and 14, and convey the developer 5 in the direction of the arrow, respectively. Spiral blade material 15, 16
One end side of the rotating shaft 14 of the first lower auger 8 extends outward to form a rotating shaft 17 of the second lower auger 9, and the rotating shaft 17 of the second lower auger 9 is formed of a rotating shaft 17 of the second lower auger 9. A second lower auger 9 is constructed by attaching a spiral blade member 18 whose conveyance direction is different from that of the first lower auger 8 .

Also, on the upper side of this second lower auger 9, there is a second
As shown in the figure, the magnetic brush developing device of the present invention is provided with a toner supply section 10 consisting of a toner bottle 19 and a supply roller 21 fitted in the lower opening 20 of the toner bottle 19. .

In the magnetic brush developing device of the present invention configured as described above, the excess amount of the developer 5 supplied from the first lower auger 8 to the developing roller 3 is scraped off by the brush stand adjusting plate 4. and is received on the receiving plate 6.

The developer 5 received on this receiving plate 6
is conveyed by the upper auger 7 to a first opening 11 provided on one end side of the receiving plate 6, and falls from this first opening 11 to the first lower auger 8.
As a result, the toner is supplied to the developing roller 3.

Developer 5 supplied to developing roller 3 at this time
Since the toner is supplied after being sufficiently uniformly agitated by the upper auger 7 on the receiving plate 6, its charging characteristics are excellent, and the toner is deposited on the photosensitive drum 1 in accordance with the electrostatic charge of the latent image. It becomes possible to form an image, and the copy density and copy image quality can be kept constant over a long period of time.

Further, in this device, the toner replenishing section 10 is located below the second opening 12 of the receiving plate 6.
The toner replenished from the toner and the developer 5 conveyed from the first lower auger 8 collide and mix, and a mountain of the developer 5 is formed and rises. After being conveyed from the second opening 12 onto the receiving plate 6 and sufficiently uniformly agitated by the auger 7, it is supplied to the developing roller 3 from the first lower auger 8 through the first opening 11. , the conveyance path of the replenished toner to the developing roller 3 is lengthened, its charging characteristics are improved, and as mentioned above, the copy density, especially the fog density, has the effect of being extremely stable.

Furthermore, unlike conventional magnetic brush developing devices, this device does not require bucket wheels or mixers for mixing replenishment toner and developer and supplying developer to the developing roller, so the entire device is It has the advantage of being small in size and low in cost.

In the above embodiment, the first lower auger 8 and the second lower auger 9 are connected in a straight line below the second opening 12 of the receiving plate 6, and are arranged on the side surface of the device housing 2. However, instead of this configuration, a second lower auger 9 is arranged so that its tip intersects with the first lower auger 8 at a position below the second opening 12. It is also possible to provide a configuration in which the toner is supplied from the rear side of the device housing 2.

Further, as shown in FIG. 3, a partition plate 22 is provided upright at the edge of the second opening 12 of the receiving plate 6 to receive the developer 5 and replenishment toner conveyed from the first lower auger 8. It is also possible to adopt a configuration that allows for smooth conveyance above No. 6.

Furthermore, in this embodiment, the ear stand adjusting plate 4
The developer 5 scraped off is temporarily transferred to the receiving plate 6.
Although the developer 5 is received by the upper auger 7 and then transported by the upper auger 7, it goes without saying that this arrangement may be replaced by a construction in which the developer 5 is directly dropped onto the upper auger 7 and transported.

[Effects of the Invention] By providing the upper auger and the first and second lower augers as described above, the present invention provides a bucket wheel and a bucket wheel for mixing replenishment toner and developer and supplying the developer to the developing roller. mixer etc.
Since the sophisticated components of the developing device can be eliminated, this has the effect of reducing the size and cost of the entire device.

Furthermore, in the present invention, the conveyance path from the toner replenishing section that replenishes toner into the device housing to the supply of the replenished toner to the developing roller is long, and during the conveyance, the toner and developer are transported by the upper auger. Since it can be stirred sufficiently uniformly, it has excellent charging characteristics and has the effect of maintaining stable copy density and copy image quality over a long period of time.

[Brief explanation of the drawing]

1 to 3 show embodiments of the present invention; FIG. 1 is a side sectional view of the magnetic brush developing device of the present invention, FIG. 2 is a sectional view taken from the - plane of FIG. 1, and FIG. 4 shows a sectional view of a magnetic brush developing device according to another embodiment, and FIG. 4 shows a side sectional view of a conventional magnetic brush developing device. Explanation of symbols, 1... Photosensitive drum, 2... Device housing, 3... Developing roller, 4... Ear stand adjustment plate, 5... Developer, 6... Receiving plate, 7... Upper auger, 8... ...First lower auger, 9...Second lower auger, 10...Toner supply section, 11...First opening, 12...Second opening, 13, 14, 1
7...Rotating shaft, 15, 16, 18...Blade material, 1
9... Toner bottle, 20... Opening, 21...
Supply roller, 22... partition plate.

Claims (1)

[Scope of Claims] 1. A magnetic brush developing device for a copying machine, which is disposed opposite to a photoconductor of the copying machine and supplies developer to the photoconductor holding an electrostatic latent image using a developing roller, This device is provided with a developing roller and on the back side of the developing roller, and the developer scraped off by the spike adjusting plate of the roller is transferred to a first opening of a partition member disposed below the developing roller. an upper auger for conveying the developer to the developing roller; a first lower auger provided on the lower side of the partition member for supplying the developer that has fallen from the first opening to the developing roller; and a lower side of the partition member At a position below a second opening which is provided in and a second lower auger that conveys the developer replenished with toner onto the partition member through the second opening. 2. The magnetism of the copying machine according to claim 1, wherein the first lower auger and the second lower auger are linearly connected at a position below the second opening. Brush developing device.