Cam-Based Gap Adjustment for Photoconductive Drum and Developing Roller
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Solution Overview
Problem
In image forming apparatuses using a two-component developer, the non-uniform gap between the photoconductive drum and the developing roller leads to uneven developer image concentration, causing concentration unevenness in the output image.
Innovation Solution
A gap adjusting mechanism is introduced, comprising a cam surface and a bearing member, which allows for precise adjustment of the distance between the rotating shafts of the photoconductive drum and the developing roller, ensuring a uniform gap and preventing concentration unevenness by using a cam member that contacts a bearing to accurately position the rotating shafts and maintain a consistent gap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the gears are meshed to synchronously rotate the photoconductive drum and developing roller, then the rotation synchronization is improved, but the gap uniformity deteriorates due to stress concentration at one end
Solution Approach 1:
The support structure is divided into multiple independent support points along the axial direction. The first support structure supports the photoconductive drum shaft and the second support structure supports the developing roller shaft, allowing independent adjustment and compensation of gaps at different positions to counteract the stress-induced deformation from gear meshing.
Solution Approach 2:
The gap between the photoconductive drum and developing roller is made adjustable by introducing adjustable support structures with movable components. This allows the gap to be dynamically adjusted or pre-adjusted to compensate for the stress concentration effect, maintaining uniform gap distribution along the axial direction during operation.
2Device complexity
If the gap between photoconductive drum and developing roller is fixed, then the structure is simplified, but the image concentration uniformity deteriorates due to non-uniform gap distribution
Solution Approach 1:
The support structures are designed with movable or adjustable components that allow the gap to be dynamically adjusted or pre-adjusted to compensate for the stress concentration effect. This dynamic adjustability maintains uniform gap distribution along the axial direction, ensuring consistent image concentration while adding only minimal structural complexity.
3Ease of operation
If the rotating shafts are freely supported, then the ease of operation is improved, but the gap uniformity deteriorates due to stress-induced deformation
Solution Approach 1:
The support system is segmented into multiple independent support points with adjustable components. This allows the rotating shafts to rotate freely while providing localized support and adjustment capability at different axial positions to compensate for stress-induced deformation, maintaining both operational freedom and gap uniformity.
Solution Approach 2:
The support structures incorporate adjustable parameters that allow the gap to be dynamically adjusted or pre-adjusted to compensate for the stress concentration effect. This maintains uniform gap distribution while preserving the freedom of rotation, balancing operational ease with manufacturing precision.
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 mechanism effectively maintains a uniform gap, ensuring consistent image concentration across the entire image, preventing unevenness and allowing for precise adjustment to achieve uniform image output.
Implementation Method 1
The gap adjusting member includes a cam surface, a distance of which from a center of the shaft hole varies in a turning direction
Implementation Method 2
The developing roller includes a second rotating shaft, includes a second surface opposed to the first surface of the image bearing body via a gap, includes a bearing at one end of the second rotating shaft
Data Source
AI summary
An image forming apparatus according to an embodiment includes an image bearing body, a developing roller, a housing, and a gap adjusting member. The image bearing body includes a first rotating shaft and includes a first surface on which a latent image is formed. The developing roller includes a second rotating shaft, includes a second surface, includes a bearing, and supplies a developer to the latent image and develops the latent image. The housing rotatably supports the second rotating shaft. The gap adjusting member includes a shaft hole for rotatably receiving one end of the first rotating shaft and includes a cam surface. The gap adjusting member is turned around the first rotating shaft and is fixed to the housing in a turning position where a gap is uniform in a direction of the second rotating shaft of the developing roller.