Developing Device Inner Wall Geometry for Toner Circulation
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Solution Overview
Problem
When a developing device is disposed above an image carrier, the developer needs to be lifted from the developing region to the transport unit, leading to poor circulation and potential image defects due to developer puddle formation.
Innovation Solution
A developing device with a developing unit that rotates around a first axis and a transport unit rotating around a second axis, where the inner wall surface of the container chamber guides the developer between specific planes to facilitate smooth lifting and prevent puddle formation, reducing image defects with a simpler structure than existing solutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the developing device is disposed above the image carrier to shorten the toner supply path, then the device size is reduced, but the developer circulation becomes poor and developer puddle is formed
Solution Approach 1:
The transport unit rotates around a second rotation axis that is positioned above the first rotation axis, creating a three-dimensional developer transport path. This vertical arrangement of rotation axes allows the developer to be transported upward from the developing region to the storage region, solving the circulation problem while maintaining the compact vertical structure of the developing device positioned above the image carrier.
Solution Approach 2:
The developing device is divided into distinct functional regions: a developing region where the developing unit contacts the image carrier, and a storage region positioned above it. The transport unit acts as a separator and connector between these regions, transporting developer upward from the developing region to the storage region. This segmentation allows independent optimization of each region's function while maintaining overall compactness.
2Device complexity
If the developing device is disposed above the image carrier, then the structure is more compact, but developer puddle is formed leading to image defects
Solution Approach 1:
The transport unit serves as an intermediary mechanism between the developing unit and the storage region. It receives developer from the developing region, transports it upward along a controlled path defined by the container chamber inner wall, and delivers it to the storage region. This intermediary function prevents developer accumulation and puddle formation by ensuring continuous, controlled developer movement through the vertical space.
Solution Approach 2:
The inner wall surface of the container chamber is configured with specific geometric features (located between the first plane tangent to the developer lifting region and the second plane including both rotation axes) that passively guide the developer flow. The developer is lifted and transported along the inner wall surface without requiring additional active components, utilizing the geometric configuration itself to control the flow path and prevent puddle formation.
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
The solution ensures efficient developer circulation and reduces image defects by minimizing the space required for developer lifting, maintaining a stable developer supply to the developing region, even when the developing device is positioned above the image carrier.
Implementation Method 1
the developing unit being configured to develop an electrostatic latent image on the image carrier with the toner in the developer
Implementation Method 2
a transport unit disposed in the container chamber, the transport unit being configured to rotate around a second rotation axis that is above the first rotation axis so as to transport the developer in a second rotation axis direction
Data Source
AI summary
A developing device includes a developing housing, a developing unit, and a transport unit. The developing housing includes a container chamber containing a developer. The developing unit rotates around a first rotation axis while carrying the developer on a surface thereof to deliver the developer. At least a partial region of the developing unit is exposed from the developing housing in a developing region below the first rotation axis such that the developing unit faces an image carrier. The developing unit develops an electrostatic latent image. The transport unit is disposed in the container chamber. The transport unit rotates around a second rotation axis to transport the developer. A part of an inner wall surface of the container chamber on a developer lifting side in which the surface of the developing unit moves toward the transport unit is located between a first plane and a second plane.