Toner conveyance device and image forming apparatus including the same

Patent metadata

Field	Value
Publication number	US-10175611-B2
Application number	US-201815921803-A
Country	US
Kind code	B2
Filing date	Mar 15, 2018
Priority date	Mar 23, 2017
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

A toner conveyance device includes a conveying screw having a shaft and a spiral blade. The spiral blade includes a start end-side blade adjacent to a bearing positioned at a start end part side in a toner conveyance path, a terminal-side blade adjacent to a bearing positioned at a terminal part side, and an intermediate blade. A toner discharge port is provided between the intermediate blade and the terminal-side blade. A spiral winding direction of the terminal-side blade is opposite to that of the intermediate blade, a spiral winding direction of the start end-side blade is equal to that of the intermediate blade, and a blade diameter of the start end-side blade and a blade diameter of the terminal-side blade are smaller than that of the intermediate blade.

First claim

What is claimed is:

1. A toner conveyance device comprising:
a casing which forms a toner conveyance path therein and has a toner discharge port opened downward at a position near a terminal part of the toner conveyance path;
a pair of bearings; and
a conveying screw which includes a shaft having both ends supported by the pair of bearings, and a spiral blade protruding from a peripheral surface of the shaft in a spiral shape, and conveys toner in the toner conveyance path from a start end part to the terminal part of the toner conveyance path by rotating in a predetermined direction,
wherein the spiral blade includes a start end-side blade adjacent to the bearing positioned at a start end part side in the toner conveyance path, a terminal-side blade adjacent to the bearing positioned at a terminal side in the toner conveyance path, and an intermediate blade formed between the start end-side blade and the terminal-side blade,
the toner discharge port is provided between the intermediate blade and the terminal-side blade,
a spiral winding direction of the terminal-side blade is opposite to a spiral winding direction of the intermediate blade,
a spiral winding direction of the start end-side blade is equal to the spiral winding direction of the intermediate blade, and
a blade diameter of the start end-side blade and a blade diameter of the terminal-side blade are smaller than a blade diameter of the intermediate blade.

2. The toner conveyance device of claim 1 ,
wherein, in the toner conveyance path, a start end-side cavity and a terminal-side cavity are formed to respectively receive the start end-side blade and the terminal-side blade, and
a gap between an inner peripheral surface of the start end-side cavity and an outer end in a radial direction of the start end-side blade and a gap between an inner peripheral surface of the terminal-side cavity and an outer end in the radial direction of the terminal-side blade are larger than a gap between an inner peripheral surface of the toner conveyance path and an outer end in the radial direction of the intermediate blade.

3. The toner conveyance device of claim 1 , further comprising:
annular seal members respectively provided between the pair of bearings and the spiral blade to prevent infiltration of toner into the bearings; and
seal holders which hold the seal members,
wherein each of the seal holders includes a cylindrical member having an inner peripheral surface to which the seal member is fitted, and a regulating plate having a through hole through which the shaft passes and abutting an end surface of the seal member, and
maximum blade diameters of the start end-side blade and the terminal-side blade are smaller than a hole diameter of the through hole formed in the regulating plate of the seal holder.

4. The toner conveyance device of claim 1 ,
wherein the start end-side blade and the terminal-side blade are positioned outward from a range in which toner falls in the toner conveyance path.

5. The toner conveyance device of claim 1 ,
wherein the toner is low melt toner.

6. An image forming apparatus including the toner conveyance device of claim 1 .

Assignees

• Kyocera Document Solutions Inc

Inventors

• Nemoto Shinji

Classifications

• G03G21/105

  Arrangements for conveying toner waste · CPC title

• G03G15/0891 Primary

  for conveying or circulating developer, e.g. augers · CPC title

• B65G33/30

  with a discontinuous helical surface · CPC title

• B65G33/22

  with means for retarding material flow at the delivery end of the housing · CPC title

• G03G2221/0005

  Cleaning of residual toner · CPC title