Stir-transport member, development device provided therewith, and image forming apparatus

摘要

A stir-transport member is formed on a circumferential surface of a rotation shaft with a first spiral blade, and a second spiral blade formed to overlap the region of the first spiral blade and is opposite the first spiral blade in phase and having a smaller radial-direction height than the first spiral blade. Sections of the spiral blades along the cross longitudinal direction thereof have trapezoidal shapes. The first spiral blade have a plurality of first swell portions, a part of each corresponding to a bottom of the trapezoidal shape and is more swollen than the other portions. The second spiral blade have a plurality of second swell portions, a part of each corresponding to the bottom of the trapezoidal shape and is more swollen than the other portions. The first spiral blade cross the second spiral blade at least at one of the first swell portions per turn.

主权项

1. A stir-transport member, comprising:
a rotation shaft which is rotatably supported in a powder container; a first spiral blade which is formed on an outer circumferential surface of the rotation shaft to transport powder in an axial direction when the rotation shaft rotates, the first spiral blade having a trapezoidal shape in section taken along a direction that crosses a longitudinal direction of the first spiral blade, the first spiral blade having a plurality of first swell portions, in each of which a part corresponding to a bottom of the trapezoidal shape is more swollen than in other portions of the first spiral blade, formed in a turn of the first spiral blade around the rotation shaft; and a second spiral blade which is formed on the outer circumferential surface of the rotation shaft so as to overlap a region where the first spiral blade is formed, the second spiral blade being opposite to the first spiral blade in phase, the second spiral blade being formed to have a smaller radial-direction height than the first spiral blade, the second spiral blade having a trapezoidal shape in section taken along a direction that crosses a longitudinal direction of the second spiral blade, the second spiral blade having a plurality of second swell portions, in each of which a part corresponding to the bottom of the trapezoidal shape is more swollen than in other portions of the second spiral blade, formed in a turn of the second spiral blade around the rotation shaft, wherein the first spiral blade crosses the second spiral blade at least at one of the first swell portions in a turn thereof around the rotation shaft, the second spiral blade crosses the first swell portions at the second swell portions, and the first spiral blade and the second spiral blade have formed therein the first swell portions and the second swell portions, respectively, at four positions at intervals of 90°, and the first spiral blade and the second spiral blade cross each other at two of the first swell portions that are apart from each other by 180° in a turn of the first spiral blade around the rotation shaft and two of the second swell portions that are apart from each other by 180° in a turn of the second spiral blade around the rotation shaft.