Toner Delivery Shield Geometry for Hopper Contamination
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Solution Overview
Problem
In electrophotographic image forming apparatuses, the toner delivery portion of the replenishment developer container often becomes soiled with toner, disrupting continuous printing operations and requiring frequent cartridge replacements, which complicates the design of the hopper and toner cartridge interface.
Innovation Solution
The apparatus incorporates a developer supply container with a projected portion and a shield portion, where the shield portion is positioned to prevent toner from adhering to the toner delivery portion by ensuring L1 > L2 × 0.8 and D2 > D1, with L1 being the shield length, L2 the projected portion length, D1 the maximum width of the projected portion, and D2 the width of the shield portion, thereby maintaining the toner's flow path and preventing contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the toner delivery portion is inserted deep into the hopper to increase toner capacity, then the amount of toner that can be held increases, but the toner delivery portion becomes soiled with toner
Solution Approach 1:
A shield portion is introduced as an intermediary element between the toner delivery portion and the toner in the hopper. This shield prevents direct contact between the delivery portion and toner, allowing the delivery portion to be inserted deeper into the hopper to increase toner capacity without becoming soiled.
Solution Approach 2:
The solution moves from a one-dimensional insertion depth problem to a three-dimensional spatial arrangement by adding the shield portion. The shield creates a protective spatial zone around the delivery portion, enabling deeper insertion while maintaining cleanliness through vertical and radial positioning rather than just increasing insertion depth.
2Duration of action of moving object
If the hopper size is increased to extend continuous run capability, then the printing duration increases, but the device size increases
Solution Approach 1:
The shield portion is designed with specific dimensional relationships (L1 > L2 × 0.8 and D2 > D1) that optimize its protective function while minimizing the volume it occupies. This allows the hopper to be compact yet still provide extended continuous run capability through efficient space utilization.
3Productivity
If the toner delivery portion is positioned to discharge toner to the center of the hopper, then toner accumulation efficiency increases, but the delivery portion contacts more toner and becomes soiled
Solution Approach 1:
The shield portion serves as a mediator that allows the delivery portion to be positioned centrally for optimal toner accumulation while preventing direct contact between the delivery portion surface and the toner bulk, thus maintaining productivity without the harmful effect of soiling.
Data Source
AI summary
An image forming apparatus includes an image developer unit to develop an electrostatic latent image formed on an image bearing member, using toner, and a toner container detachably mounted to a main assembly. The toner container includes a toner discharging portion having a toner discharge opening, and a storage container to store the discharge toner and to supply the stored toner. The toner discharging portion extends at least partly in the storage container through an opening of the storage container, and a cover covers the toner discharging portion and extends inwardly from an inside of a wall of the storage container, at least below the toner discharging portion. A length L1 by which the cover extends from the wall inwardly of the storage container, and a length L2 by which the toner discharging portion extends from the opening inwardly of the storage container satisfy L1<L2.