Developing Device Air Flow Passage for Pressure Control
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Solution Overview
Problem
Developing devices with two-component developers face issues with internal pressure increase and toner scattering due to external air introduction, leading to excessive developer discharge and print quality degradation.
Innovation Solution
The developing device incorporates an air flow passage that circulates air between the inside and outside, using seal members and magnetic poles to capture splashed toner and prevent external air introduction, while an air vent with a filter reduces internal pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the developer roller rotates to transport developer, then toner is delivered to the photosensitive body, but external air is introduced into the developing device causing internal pressure increase
Solution Approach 1:
A flow passage is introduced as an intermediary component to manage air flow. The flow passage allows controlled air circulation between the inside and outside of the developing device, preventing pressure buildup while maintaining the developer transport function. The flow passage acts as a mediator that resolves the conflict between continuous rotation for productivity and air introduction prevention.
2Stress or pressure
If air circulates freely to reduce pressure, then internal pressure is suppressed, but toner scatters and is carried outside
Solution Approach 1:
The flow passage serves as a controlled intermediary that directs air flow through specific paths. By confining air circulation within the flow passage structure, the system prevents uncontrolled air movement that would carry toner outside, while still achieving pressure relief through controlled ventilation.
Solution Approach 2:
The flow passage creates localized air flow patterns with specific characteristics in different regions. The air flow is concentrated in the flow passage area rather than being uniform throughout, allowing pressure equalization without creating turbulent flows that would scatter toner.
3Object-generated harmful factors
If seal members are added to prevent air introduction, then toner scattering is reduced, but device complexity increases
Solution Approach 1:
The flow passage structure performs multiple functions simultaneously: it controls air flow to prevent pressure buildup, acts as a barrier to prevent toner escape, and maintains the rotational dynamics of the developer roller. By making this single component multi-functional, the system reduces the need for additional separate seal members, thereby limiting the increase in device complexity.
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 solution effectively suppresses internal pressure increases, reduces toner scattering, and prevents excessive developer discharge, thereby improving print quality and maintaining optimal toner/carrier mixing ratios.
Implementation Method 1
transported and magnetically absorbed onto the rotating developer roller
Implementation Method 2
circulate air through the flow passage between the inside and the outside of the developing device, thereby suppressing increase in the internal pressure
Implementation Method 3
the developer on the developer roller can capture and collect splashed toner
Data Source
Figure 1
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AI summary
A developing device includes a developer roller to rotate in a rotation direction, a photosensitive body adjacent the developer roller, and an air flow passage extending through a non-image forming region at a longitudinal end of the developer roller. A closest position is defined where the developer roller and a photosensitive body are closest to one another. The air flow passage extends from inside the developing device and forms an air flow directed toward an upstream side of the closest position, relative to the rotation direction of the developer roller.