Developing Device Vertical Chamber Mixing
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Solution Overview
Problem
In image forming apparatuses, the miniaturization of developing devices leads to uneven developer distribution due to changes in flowability, causing issues like fogged images and uneven image density, particularly when toner is replenished in areas with low developer concentration, resulting in insufficient mixing with the carrier.
Innovation Solution
A developing device with a first and second stirring-conveyance member, where the second communication portion allows developer to move upward by the second stirring-conveyance member and downward by the first, ensuring sufficient mixing and circulation between the first and second conveyance chambers, and a guide member directs the developer to fall into the first conveyance chamber, promoting even distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the first conveyance chamber and second conveyance chamber are arranged one above the other to miniaturize the developing device, then the horizontal space is reduced, but the developer circulation balance deteriorates due to gravity-induced uneven distribution
Solution Approach 1:
The conveyance chamber is divided into a first conveyance chamber and a second conveyance chamber arranged vertically, with each chamber having dedicated stirring-conveyance members. This segmentation allows independent control of developer circulation in each chamber, compensating for gravity-induced distribution issues while maintaining compact horizontal footprint.
Solution Approach 2:
Instead of having a single horizontal conveyance path, the invention inverts the arrangement to vertical stacking with communication paths allowing developer to flow between chambers. The stirring-conveyance members rotate in opposite directions to create bidirectional circulation, counteracting the natural gravity-driven flow and maintaining uniform distribution.
2Quantity of substance
If toner is replenished to portions with low developer concentration, then the local toner concentration increases, but the mixing with carrier becomes insufficient causing fogged images
Solution Approach 1:
The stirring-conveyance members perform periodic rotation in opposite directions, creating cyclic circulation patterns that continuously mix replenished toner with carrier. This periodic action ensures uniform distribution of toner throughout the developer, preventing local aggregation and fogged images.
Solution Approach 2:
The invention changes the rotation direction parameter of the stirring-conveyance members, with the first member rotating in one direction and the second member rotating in the opposite direction. This parameter change creates enhanced mixing action that thoroughly incorporates replenished toner with the carrier, maintaining developer uniformity.
3Speed
If the second stirring-conveyance member conveys developer upward against gravity, then the developer circulation is maintained, but the circulation balance changes due to flowability variations
Solution Approach 1:
The bidirectional circulation system creates a feedback mechanism where developer flowing downward due to gravity in one chamber is compensated by upward conveyance in the other chamber. This feedback loop maintains circulation balance even when flowability changes, as the opposite rotation directions automatically adjust the circulation dynamics.
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 ensures thorough mixing of replenished toner with the developer, reducing aggregation and fogged images, and maintaining even image density by preventing developer compression and stagnation, thus enhancing the miniaturization and performance of image forming apparatuses.
Implementation Method 1
there is an area where the developer is conveyed against gravity, from the first conveyance chamber to the second conveyance chamber
Implementation Method 2
the second stirring-conveyance member supplies the developer to the developing roller, while conveying the developer to the other side (the side opposite from the one side)
Implementation Method 3
a guide member is disposed which guides, to the downstream side in the first direction, the developer that is conveyed from the second conveyance chamber, passing through the second communication portion, and falls into the first conveyance chamber
Data Source
AI summary
A developing device includes a developing container including a first conveyance chamber and a second conveyance chamber disposed above the first conveyance chamber, a first stirring-conveyance member which conveys developer in the first conveyance chamber in a first direction, a second stirring-conveyance member which conveys the developer in the second conveyance chamber in a second direction opposite to the first direction, and a developer carrier. A second communication portion is formed which allows the first and second conveyance chambers to communicate with each other at their end portions on a downstream side in the second direction. In the first conveyance chamber, a guide member is disposed which guides, to the downstream side in the first direction, the developer passing through the second communication portion to fall into the first conveyance chamber.