Developing Device Toner Inlet Clogging Prevention
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Solution Overview
Problem
Existing developing devices face issues with clogging near the toner inlet section and poor charging characteristics of recycled toner particles, especially in high-temperature environments or during low-darkness printing, due to reduced fluidity and altered charging properties of recycled toner particles.
Innovation Solution
The developing device incorporates a conveyance power reduction portion with a rear spiral feeder having a conveyance power reduction mechanism and strategically positioned toner inlet openings upstream of this portion, ensuring that toner particles are upwardly surged and well mixed with carrier particles, improving fluidity and charging characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conveyance power reduction portion is provided in the rear conveyance passage to retain toner particles, then automatic adjustment of toner supply amount is achieved, but clogging occurs near the toner inlet section especially in high-temperature environments or during low-darkness printing
Solution Approach 1:
The patent extracts the harmful effect of toner particle retention by providing a separate discharge portion that actively removes retained toner particles from the rear conveyance passage. This prevents clogging near the toner inlet section while maintaining the automatic supply adjustment function. The discharge portion acts as an independent mechanism to eliminate the accumulated toner that would otherwise cause blockages.
Solution Approach 2:
The patent applies the discarding principle by providing a discharge portion that actively removes and discards retained toner particles from the rear conveyance passage. This prevents the accumulation of toner particles that would lead to clogging, while the main conveyance mechanism continues to provide automatic supply adjustment. The discharged toner can be recovered and reused, maintaining material efficiency.
2Quantity of substance
If recycled toner particles are resupplied to the developing device, then resource utilization is improved, but charging characteristics deteriorate due to reduced fluidity and altered charging properties
Solution Approach 1:
The patent applies parameter changes by actively controlling the discharge of retained toner particles through the discharge portion. This changes the physical state and distribution parameters of recycled toner particles, improving their fluidity and charging characteristics. By adjusting the discharge rate and timing, the system optimizes the properties of resupplied toner to maintain reliable charging performance.
Solution Approach 2:
The patent applies preliminary action by discharging retained toner particles from the rear conveyance passage before they are resupplied to the developing device. This preliminary discharge treatment improves the charging characteristics of recycled toner particles by removing accumulated particles with degraded properties, ensuring that only toner particles with optimal charging characteristics are resupplied to the developing device.
3Ease of operation
If toner particles are retained between the conveyance power reduction portion and the toner inlet section, then supply restriction is achieved when enough toner exists, but clogging occurs when toner particles are consumed and space is formed
Solution Approach 1:
The patent applies feedback by providing a discharge portion that actively monitors and responds to the state of retained toner particles in the rear conveyance passage. When space is formed indicating toner consumption, the discharge mechanism activates to prevent clogging. This feedback control ensures continuous reliable supply by dynamically adjusting the discharge rate based on the actual toner particle state, maintaining both supply restriction and continuous availability.
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 prevents clogging and enhances the charging characteristics of toner particles, ensuring stable and constant toner supply to the developing roller, even with recycled toner particles, thereby maintaining image quality during extended low-darkness printing.
Implementation Method 1
a rear conveyer and a front conveyer which are rotatable about their respective axes to convey developer particles in specified conveyance directions
Implementation Method 2
the rear conveyer having a conveyance power reduction portion for reducing the conveyance power locally
Data Source
AI summary
A housing of a developing device has a circulating conveyance passage with a front conveyance passage along a developing roller and a rear conveyance passage parallel to the front conveyance passage. Front and rear spiral feeders are provided in the front and rear conveyance passages for conveying developer particles. The housing has a first developer inlet opening for receiving developer particles from a developer supplier and a second developer inlet opening for receiving recycled developer particles. The rear spiral feeder includes a conveyance power reduction portion at a position downstream from the first and second developer inlet openings and locally reduces conveyance power. The first and second developer inlet openings upstream of the conveyance power reduction portion and are where developer particles are likely to be upwardly surged due to the rotation of the rear conveyer.