JPH0247934B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a powder stirrer used as a stirring roller or the like in a developer tank of an electrophotographic copying machine.

<Prior art and its disadvantages> The agitator in the developer tank of a conventional copying machine contains two-component developer, toner and developer, in the developer container, and stirs the two-component developer to make it uniform. It is stirred by a container. In such a two-component development system, if the latent image on the photoreceptor drum is always formed in a localized manner, the toner density will be uneven and a density difference will occur in the copied image. The unevenness of toner consumption in the axial direction of the photoreceptor drum will remain unless it is actively resolved. Therefore, the stirring ability in the axial direction is an important function of the stirrer. FIGS. 5 and 6 show conventionally implemented or proposed agitators and experimental results regarding the agitators. Two toners with different concentrations were placed in the developer tank in the axial direction of the agitator, and the changes in toner concentration at predetermined measurement points over time were measured (P1, P2, and P3 are the left and right positions in the developer tank). , center, and right, respectively). In the case of a stirrer with semicircular rotor blades attached obliquely to the rotation axis (see Figures 5A and 6A), there are also elliptical stirring blades attached to the rotation axis and On the other hand, those provided with stirring blades attached in parallel (see FIGS. 5B and 6B) have inferior fluidity in the left-right direction, and are not stirred symmetrically. This bias is also one of the reasons for delaying the time for concentration uniformity. Furthermore, in the past, two stirrers were installed and these were rotated in reverse order, but this resulted in problems such as the device becoming larger and more complicated (Japanese Patent Laid-Open No. 58-25669, Japanese Patent Laid-Open No. 56 −36671, Japanese Patent Application Publication No. 1983
-38970, see Utility Model Application Publication No. 59-16939).

<Object of the Invention> The object of the present invention is to provide a stirrer which has been made to solve the above-mentioned conventional problems and has improved stirring performance in the axial direction of the stirrer.

<Configuration and Effects of the Invention> The present invention includes a first stirring blade attached obliquely to the rotating shaft and a second stirring blade attached axially to the rotating shaft, It is characterized in that the shaft is hollow, a spiral groove is formed on its inner surface, and a plurality of through holes are provided in the rotating shaft.

According to the above configuration, the flow of the powder is not biased in one direction, and an effective flow can be obtained particularly in the axial direction of the stirrer.

<Example> FIG. 1 shows a stirrer according to the present invention. In the figure, reference numeral 13 indicates a rotating shaft, and reference numeral 11 indicates a substantially disk-shaped first
The stirring blade 12 is a second stirring blade attached in the axial direction with respect to the rotating shaft. The rotating shaft is hollow and has a spiral groove 15 formed on its inner surface, and through holes 14 formed at predetermined locations. Further, the second stirring blade 12 is provided with a notch at a predetermined location, and the developer around the stirrer is caused to flow in one of the axial directions of the rotating shaft by the rotation of the stirrer. On the other hand, the developer material entering the rotating shaft through the through hole 14 moves inside the shaft as the stirrer rotates due to a spiral groove provided on its inner surface.

FIG. 2 is a diagram showing the flow of these developers. As shown in the figure, the developer outside the stirrer flows in the direction of arrow A, and the developer inside the rotating shaft of the stirrer flows in the direction of arrow B. The developer inside this rotating shaft flows into the through hole on the left side, flows rightward along the internal spiral groove, and flows out of the agitator through the through hole provided on the right side. FIG. 3 shows a cross section of the agitator rotating shaft, and the relationship between the spiral groove 15 inside the rotating shaft and the through hole 14 is as shown in the figure. In this way, by reversing the flow of developer outside the agitator and the flow of developer inside the rotating shaft, the axial fluidity of the agitator as a whole is improved, and the axial agitation performance is improved. Can be done.

FIG. 4 shows a method of forming a spiral groove inside the rotating shaft of a stirrer according to the present invention. The agitator is made of resin molding, and the first and second external agitating blades are molded using upper and lower split molds of an upper mold and a lower mold. On the other hand, the spiral groove inside the rotating shaft is formed by a rotating drawn side core. The arrow in A in the figure indicates the direction in which the upper mold and the lower mold are divided. Further, arrows in FIG. B indicate the rotational direction and the pulling direction of the side core. As described above, according to the present invention, it is possible to improve the fluidity of powder in the axial direction of the stirrer, and moreover, it exhibits a stirring effect with excellent left-right symmetry.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a stirrer according to the present invention;
FIG. 2 is a diagram showing the flow of developer outside the agitator and inside the rotating shaft of the agitator, FIG. 3 is a cross-sectional view of the agitator rotating shaft, and FIG. 4 is a diagram showing the flow of the developer inside the agitator's rotating shaft. FIG. 5 is a diagram showing a molding method, FIG. 5 is a diagram showing a conventionally implemented or proposed stirrer, and FIG. 6 is a diagram showing the results of these conventional experiments. DESCRIPTION OF SYMBOLS 1... Stirrer, 2... Side core, 11... First stirring blade, 12... Second stirring blade, 13... Rotating shaft, 14... Through hole, 15... Spiral-shaped groove.

Claims (1)

[Claims] 1. A first stirring blade having a rotating shaft that is rotatably held and attached obliquely to the rotating shaft;
It consists of a second stirring blade attached in the axial direction to the rotating shaft, the rotating shaft is hollow and a spiral groove is formed on its inner surface, and the rotating shaft is provided with a plurality of through holes. A powder mixer characterized by: