Developer Conveyance Mechanism for Image Density Uniformity
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Solution Overview
Problem
Existing image forming apparatuses experience density unevenness and reduction due to insufficient developer agitation, particularly when handling high image area ratios, despite attempts to enhance agitation capability through additional conveyance mechanisms.
Innovation Solution
The image forming apparatus incorporates a development unit with a first, second, and third developer conveyance mechanism, along with an opening area, where the first mechanism supplies developer to a carrying member, the second mechanism conveys it obliquely upward, and the third mechanism collects and transports developer back to the second mechanism, ensuring efficient agitation and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a developer conveyance mechanism is disposed in a longitudinal direction with separate first and second conveyers, then the agitation capability with respect to the developer is increased, but density unevenness and density reduction occur due to insufficient agitation
Solution Approach 1:
The developer conveyance mechanism is divided into multiple independent conveyers (first conveyer for collecting developer, second conveyer for supplying developer, and third conveyer for circulating developer). Each conveyer performs a specific function in the developer circulation path, creating segmented functional zones that collectively achieve comprehensive agitation while maintaining density uniformity.
Solution Approach 2:
The third conveyer is disposed in a lateral direction, adding a dimensional aspect to the developer circulation path that was previously only in the longitudinal direction. This lateral circulation path enables the circulating developer to return to the first conveyer, creating a multi-dimensional agitation pattern that effectively prevents density unevenness.
2Ease of operation
If additional developer conveyers are added to enhance agitation capability, then the developer can be circulated more effectively, but the device complexity increases
Solution Approach 1:
Each conveyer in the system is designed with multi-functionality. The first conveyer both collects developer from the development unit and serves as a circulation point for the third conveyer. The second conveyer supplies developer while also receiving circulating developer. This multi-functional design reduces the need for additional dedicated components, managing system complexity while maintaining effective agitation.
3Device complexity
If the developer is collected and conveyed in a single direction, then the conveyance mechanism is simplified, but developer depletion occurs in the development unit
Solution Approach 1:
The third conveyer establishes a continuous circulation path that returns circulating developer from the second conveyer back to the first conveyer. This continuous circulation ensures that developer is constantly replenished in the development unit, preventing developer depletion and maintaining reliable operation without requiring complex intermittent replenishment mechanisms.
Data Source
AI summary
An image forming apparatus includes an electrostatic latent image carrier carrying an electrostatic latent image and a development unit that develops the electrostatic latent image. The development unit includes a developer carrier, first, second, and third developer conveyers, and an opening area. The developer carrier is disposed opposing to the electrostatic latent image carrier. The first developer conveyer supplies a developer to the developer carrier. The second developer conveyer conveys the developer, and transports the developer to the first developer conveyer at a downstream side of the second developer conveyer. The third developer conveyer collects the developer, conveys the developer, and transports the developer to the second developer conveyer in a downstream side of the third developer conveyer. The opening area, disposed higher than a lowermost point of the first developer conveyer, allows the developer to drop from the first developer conveyer to the second developer conveyer.