Developing Unit Film Attachment for Toner Accumulation Control
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Solution Overview
Problem
Existing developing units face challenges in preventing toner accumulation on the developer holding member, which can lead to image defects due to the formation of lumps on the covering member.
Innovation Solution
A developing unit is designed with a covering member that includes a film attached at ends and an intermediate position, ensuring contact with the developer layer. The intermediate position of the film is set according to the height of the developer layer determined by the developer attracting magnet, allowing the film to sag conformingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a film is provided on the covering member to contact the developer layer, then toner accumulation is suppressed, but it becomes difficult to maintain a stable contact state between the film and the developer layer
Solution Approach 1:
The patent makes the film detachable rather than permanently fixed, allowing it to be positioned dynamically at the optimal location where it contacts the developer layer. This resolves the contradiction by enabling the film to maintain stable contact (improving reliability) while still suppressing toner accumulation (improving the harmful factor prevention).
Solution Approach 2:
The patent segments the covering member structure by separating the film from the main covering member body, allowing independent positioning and adjustment. This enables the film to be placed precisely where needed to contact the developer layer, maintaining stable contact while preventing toner accumulation.
2Reliability
If the intermediate position of the film is set according to the developer layer height determined by the developer attracting magnet, then the film maintains stable contact with the developer layer, but the structure becomes more complex
Solution Approach 1:
The patent uses the existing developer attracting magnet's magnetic field to naturally define the developer layer height, and positions the film's intermediate detachment portion to correspond to this naturally formed height. The system uses its own existing components (the magnet) to guide the film positioning, avoiding additional complex positioning mechanisms while maintaining stable contact.
3Device complexity
If the film is attached only at the ends of the covering member, then the structure is simple, but the film cannot conform to the change in developer layer height, causing toner accumulation
Solution Approach 1:
The patent applies partial attachment by providing adhesive only at the end portions of the film rather than along the entire length. This simple partial attachment (maintaining low complexity) allows the intermediate portion to detach and contact the developer layer, conforming to its height variations and preventing toner accumulation.
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 effectively suppresses toner accumulation, maintains a stable contact state between the film and the developer layer, and prevents image defects by ensuring consistent contact with the developer layer.
Implementation Method 1
a developer holding member that holds developer to be supplied to an image carrier on which an electrostatic latent image is formed, the developer containing toner and carrier, and that includes at least one developer attracting magnet
Data Source
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AI summary
A developing unit includes: a developer holding member that holds developer to be supplied to an image carrier on which an electrostatic latent image is formed, the developer containing toner and carrier, and that includes at least one developer attracting magnet; a covering member that covers a part of the developer holding member; and a film that is attached to the covering member at ends and an intermediate position of the film in a circumferential direction of the developer holding member so as to be in contact with the developer held on the developer holding member.