JPS6343470Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toner supply device for developing an electrostatic image in an electrophotographic copying machine, an electrostatic copying machine, or the like.

Various toner replenishing devices of this type have been proposed and put into practical use. One such method is, for example, as disclosed in Japanese Utility Model Publication No. 40-8684, in which a grooved roller is provided at the bottom of a toner container, and by rotating this roller, the toner is discharged through the groove. However, in this case, since the grooves on the roller are provided at predetermined intervals, toner supply is intermittent, which causes temporary density unevenness in the toner in the developing device, making it difficult to produce copies with uniform image quality. Has no drawbacks.

In addition, in other conventional devices, toner powder is supplied directly from the toner container to the developing device, so the powder tends to become large due to the agglomeration of the toner powder, and it takes time to stir the toner in the developing device to keep the toner concentration constant. In the meantime, uneven development is likely to occur. Moreover, when using an intermittent toner supply method, it is effective in keeping the toner concentration in the developer constant over a relatively long period of time; However, there is a problem in that the toner concentration in the developer temporarily increases, and the toner concentration decreases when replenishment is not performed, and also has the disadvantage that fog occurs when the toner concentration temporarily increases.

The present invention is intended to improve the drawbacks of the conventional toner replenishing device as described above, and is a toner replenishing device that replenishes the toner in the toner container to the developing device by controlling the toner with a rotating roller provided near the outlet of the toner container. At least one guide member is provided that guides the toner from the discharge port of the toner container onto the surface of the rotating roller, and a part of the guide member is brought into pressure contact with the rotating roller, and at the pressure contact point, the toner is continuously guided in the rotational direction of the rotating roller. The toner replenishing device is characterized in that a gap is formed in the toner container, and the toner powder in the toner container is transported to the developing device by a rotating roller near the discharge port, and a guide member The toner is crushed by a rotating roller, falls through fine gaps, becomes a fine powder toner that can be easily stirred, and is continuously supplied into the developing device. Therefore, the toner in the developing device can always have a uniform density, and copies without uneven development or fog can be obtained.

The present invention will be explained below with reference to the illustrated embodiments.

In FIG. 1, reference numeral 1 denotes a conventionally known magnetic brush developing device 2, which is a toner replenishing device. Housing 10 of the developing device
A doctor blade 11 for trimming the tip of the magnetic brush, a scraper 19 for peeling the developer from the sleeve 12, and a block 13 for holding magnets 14 to 18 are fixed to the magnetic brush. Further, a sleeve 12 and a stirring device 20 are rotatably attached to the housing 10. It is well known that by rotating the sleeve 12 in the direction of arrow A by a motor (not shown), magnetic brushes are formed one after another on the sleeve 12 facing the magnet 14, thereby performing development. The developer that has passed through the development position is scraped off from the sleeve by the scraper 19 and falls into the developing device, after which the toner is stirred by the stirring device 20 and returned to the bottom of the housing 10.

The toner replenishing device 2 is formed of a main housing 30.
A toner discharge roller 31 that rotates in the direction of arrow B is provided at the bottom of the casing 30, and a stirring device 32 is provided within the casing 30. As shown in FIG. 2, the toner discharge roller 31 has a circumferential surface 31a having a large number of narrow grooves 31b continuous in the direction of rotation thereof, and a rotating shaft 31c. The roller 31 may be provided facing the flow of the developer scraped off by the scraper 19 so as to come into contact with the developer scraped off by the scraper. Since the narrow grooves are continuous in the direction of rotation of the roller, the toner in the grooves falls continuously as the rotating roller rotates. At this time, when the toner scraped off by the scraper 19 contacts the circumferential surface of the rotating roller and the circumferential surface contacts the developer, the toner adhering to the circumferential surface is almost completely wiped away by the developer. Therefore, clogging of the groove of the roller 31 can be prevented. Reference numeral 33 denotes a guide plate (which may be made of an elastic material or a rigid body) that guides the toner powder discharged from the discharge port 34a provided in a part of the bottom plate 34 of the toner replenishing device onto the surface of the roller 31, and also directs the toner powder aggregates to the roller 31. Its role is to press against the surface and crush it. Since the pulverized fine powder toner is fine and enters the narrow grooves and is continuously supplied, it is easily stirred by the stirring device 20 and the toner concentration can be kept constant.

FIG. 3 shows an embodiment in which the tip of the guide plate 33 is serrated, and when this is used, the groove on the roller side may be omitted. Furthermore, the guide plate may have a corrugated shape (corrugated iron plate shape).

In short, in the embodiment of the present invention, there are many fine gaps between the toner discharge roller 31 and the guide plate 33, and toner powder is continuously discharged from the gaps when the roller rotates. The shapes of these rollers and guide plates do not matter.

In the embodiment shown in FIG. 1, it is clear that if the guide plate 33 is provided not only on the left side of the roller 31 but also on the right side, the toner powder can be discharged more reliably.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view of one embodiment of the present invention;
The figure shows an embodiment of the toner discharge roller, and FIG. 3 shows an embodiment of the guide plate. 1...Developing device, 2...Toner supply device, 12
... Sleeve, 14-18 ... Magnet, 19 ... Scraper, 20, 32 ... Stirring device, 31 ...
Toner discharge roller, 33... Guide plate, 34a...
...Toner outlet.

Claims (1)

[Scope of utility model registration request] A housing for storing replenishment toner, a toner discharge port provided at the bottom of the housing, a toner discharge roller provided below the toner discharge port, and the toner discharge port and the toner discharge roller. A guide plate provided between the toner discharge roller and a large number of narrow grooves continuous in the rotational direction on the circumferential surface of the toner discharge roller; A toner replenishing device that presses against the surface.