Developing Apparatus Forced Discharge for Developer Level Control
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Solution Overview
Problem
In electrophotographic image forming apparatuses, the accumulation of a two-component developer leads to increased developer amounts in the developing device, causing image deterioration such as density unevenness due to the simultaneous supply of carrier with toner, which results in inefficient discharge of the developer.
Innovation Solution
A developing apparatus with a tank, discharge port, supplier, replenisher, and controller that estimates the developer amount and executes a forced discharge to maintain a constant developer level by replenishing and discharging the developer, preventing the accumulation of old, deteriorated carrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the carrier is supplied to the developing device simultaneously with the supply of the toner, then the developer composition is maintained, but the developer amount in the developing device increases
Solution Approach 1:
The patent extracts and separates the carrier supply from the toner supply process. Instead of simultaneous supply, the carrier is supplied separately and sequentially to the developing device, allowing independent control of carrier amount and timing. This prevents the accumulation of excess developer while maintaining proper composition.
Solution Approach 2:
The patent implements dynamic control of carrier supply based on the actual state of the developing device. The supply amount and timing of carrier are adjusted dynamically according to the developer amount in the device, ensuring that the developer composition is maintained without causing excessive accumulation.
2Quantity of substance
If the developer surface position under the developing roller rises, then the developer is retained in the tank, but the developer once used for development is dragged by the rotation of the developing roller causing image deterioration
Solution Approach 1:
The patent employs feedback control by monitoring the developer surface position and adjusting the carrier supply accordingly. When the developer surface position rises, the system responds by controlling the carrier supply to prevent further accumulation, thereby preventing the dragging of used developer and maintaining image quality.
Solution Approach 2:
The patent takes preliminary action by controlling the carrier supply before excessive developer accumulation occurs. By regulating the carrier amount in advance based on predicted usage patterns, the system prevents the developer surface from rising to a level that would cause image deterioration.
3Quantity of substance
If the developer amount in the developing device increases, then the carrier replacement is delayed, but the charging performance deteriorates and image characteristics worsen
Solution Approach 1:
The patent enables the developing device to self-regulate its developer amount through controlled carrier supply. The system automatically adjusts the carrier supply to maintain optimal developer levels, ensuring that carrier replacement occurs at appropriate intervals to maintain charging performance without requiring external intervention.
Data Source
AI summary
A developing apparatus includes a tank configured to contain a developing agent including a toner and a carrier, the tank having a discharge port configured to discharge the developing agent overflowing from the tank, a supplier configured to develop a latent image by using the toner contained in the tank, a replenisher configured to contain the developing agent and to replenish the developing agent into the tank, and a controller configured to estimate an amount of the developing agent in the tank in according with the amount of the supplied developing agent and the amount of the replenished developing agent and to execute a forced discharge for forcibly discharging the developing agent contained in the tank from the discharge port based on the estimated amount of developing agent.