Developing Device Stirring Mechanism for Toner Agglomeration Control
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Solution Overview
Problem
In image forming apparatuses, agglomeration and solidification of developer within developing devices occur, leading to uneven distribution and reduced efficiency in toner charging and mixing, particularly in two-component development methods, where toner and carrier need to be stirred and mixed effectively to achieve the desired electric charge.
Innovation Solution
The design incorporates a stirring/transporting member with a first and second spiral, and a paddle portion on the first spiral, which enhances developer circulation and mixing by preventing stagnation and agglomeration, ensuring even distribution of toner and carrier, and includes developer breaking members to manage developer walls that form during low toner levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a circulation passage with spiral stirring members is used to mix and transport developer, then toner and carrier are stirred and mixed effectively, but developer agglomeration and adhesion occur in the developer passing portion
Solution Approach 1:
The developer passing portion is divided into multiple sections along the axial direction, with each section having a dedicated stirring member. This segmentation prevents large-scale agglomeration by continuously disrupting developer flow at multiple points along the circulation passage.
Solution Approach 2:
Multiple stirring members are configured to rotate at different speeds or directions, creating dynamic mixing patterns that adapt to varying developer flow conditions. This dynamic approach prevents stagnant zones where agglomeration would occur.
2Quantity of substance
If developer is circulated and transported through a circulation passage, then toner concentration is maintained through continuous mixing, but developer walls form and toner sensor output becomes unstable
Solution Approach 1:
The stirring members are positioned to actively disrupt developer flow before it can form stable walls that would block the toner sensor. By preliminarily breaking up developing walls, the system maintains stable sensor readings and accurate toner concentration detection.
Solution Approach 2:
The stirring members act as intermediaries between the developer flow and the toner sensor, preventing direct contact between developer walls and the sensor. This intermediary action ensures stable sensor output by eliminating direct interference from agglomerated developer.
3Device complexity
If a simple spiral stirring member is used, then the device structure remains simple, but developer agglomeration occurs and mixing efficiency decreases
Solution Approach 1:
Multiple spiral stirring members are merged into a single integrated circulation system, where each spiral works in coordination with the others. This merging approach maintains relatively simple individual component structures while achieving high mixing efficiency through their combined action.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively suppresses developer agglomeration and adhesion, maintaining stable toner sensor output values and ensuring accurate toner feeding, even with varying developer amounts and deteriorated toner flowability, thereby improving the overall efficiency of the image forming process.
Implementation Method 1
the developer is circulated and transported, while being stirred and mixed, by a stirring/transporting member arranged inside the circulation passage which is in the form of a screw
Implementation Method 2
a two-component development method, which uses a two-component developer designed to electrically charge non-magnetic toner by use of magnetic carrier
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A developing device (4) includes: a developer container (40) having first and second transport passage (40b)s, for containing developer; a developer carrier (20) for carrying, on its surface, developer inside the second transport passage (40b); a first stirring/transporting member (31) having a rotary shaft (31a) and a transport blade (31b) formed on its circumferential surface, for stirring/transporting developer inside the first transport passage (40a); a second stirring/transporting member (32) for stirring/transporting developer inside the second transport passage (40b) in a direction opposite to the first stirring/transporting member (31); a first developer passing portion (40d) for delivering developer from the first to the second transport passage (40b); and a second developer passing portion (40e) for delivering developer from the second to the first transport passage (40a). In a part of the first stirring/transporting member (31) facing the first developer passing portion (40d), a paddle portion (50) is formed which is devoid of the rotary shaft (31a) and which has a plurality of first ribs (51 a, 51b) parallel to the rotary shaft (31 a).