Developing Device Transport Chamber Segmentation for Developer Stability
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Solution Overview
Problem
In image forming apparatuses using a two-component developing system, the carrier in the developer container deteriorates due to repeated stirring, leading to diminished toner charging performance, as toner is consumed and carrier remains unconsumed.
Innovation Solution
A developing device with a developer container featuring a first and second transport chamber, a communication portion, developer supply and discharge ports, and stirring members with helical blades and a disk to manage developer flow and discharge surplus developer, ensuring fresh developer is supplied while stabilizing the developer level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the carrier is continuously stirred together with toner inside the developer container, then the developer is continuously fed to the developing roller, but the carrier deteriorates and toner charging performance diminishes
Solution Approach 1:
The developer container is divided into multiple transport chambers (first transport chamber, second transport chamber, third transport chamber) with communication portions between them. The stirring members are selectively arranged in specific chambers, allowing continuous feeding while reducing continuous stirring in the same location, thereby preventing carrier deterioration.
Solution Approach 2:
The stirring members transport developer periodically through the communication portions between transport chambers. This periodic transport action allows fresh developer to be supplied while discharged developer is removed, preventing continuous stirring degradation of the carrier.
2Reliability
If fresh developer is supplied into the developer container, then toner charging performance is maintained, but the developer level becomes unstable and varies
Solution Approach 1:
The disk portion and helical blade are arranged across a gap to create a feedback mechanism where the developer level automatically regulates itself. When developer level rises, it overflows through the gap; when level drops, the stirring action replenishes it, maintaining stable developer level and toner concentration.
Solution Approach 2:
The arrangement of the disk portion and helical blade creates a controlled gap that changes the flow parameters of developer. This gap configuration regulates the developer level by allowing overflow at a specific height, thereby stabilizing the developer composition.
3Productivity
If the disk portion and helical blade are arranged close together, then developer transport is efficient, but the developer height becomes unstable
Solution Approach 1:
The end part of the helical blade and the disk portion are arranged with a specific gap between them, creating a localized quality difference. This gap provides a release point for developer height regulation while maintaining efficient transport in other areas, stabilizing developer height without sacrificing transport efficiency.
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 maintains a stable developer level and toner concentration, reducing variations in developer amount and transport speed, thereby preventing image defects and extending developer lifespan.
Implementation Method 1
The first stirring member is composed of a rotary shaft and a first transport blade formed on the circumferential surface of the rotary shaft, and stirs and transports developer inside the first transport chamber in the axial direction of the rotary shaft. The second stirring member is composed of a rotary shaft and a second transport blade formed on the circumferential surface of the rotary shaft, and stirs and transports the developer inside the second transport chamber in the direction opposite to the first stirring member.
Implementation Method 2
The disk is formed at a position facing the communication portion on the downstream side of the second transport chamber, on the upstream side of the regulating portion in the transport direction of the developer inside the second transport chamber, and protrudes in the radial direction over the entire circumference of the rotary shaft.
Data Source
AI summary
A developing device has a developer container, first and second stirring members, and a developer carrying member. The developer container has a plurality of transport chambers including first and second transport chambers, a communication portion through which the first and second transport chambers mutually communicate in opposite end parts thereof in their longitudinal direction, a developer supply port, and a developer discharge port arranged in a downstream-side end part of the second transport chamber. The second stirring member has a second transport blade, a regulating portion formed on the downstream side of the second transport blade, a discharge blade formed on the downstream side of the regulating portion and discharging developer through the developer discharge port, and a disk formed at a position facing the downstream-side communication portion on the upstream side of the regulating portion and radially protruding over the entire circumference of a rotary shaft.