Variable Pitch Toner Screw for Stable Conveyance
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Solution Overview
Problem
Conventional toner conveying systems face issues with varying bulk density and toner concentration, leading to supply failures and image defects due to increased pressure and adhesion of toner to conveying screws, especially when temperature and environmental factors influence the system.
Innovation Solution
A toner conveying apparatus with a screw configuration where the pitch downstream in the toner conveying direction is wider than upstream, ensuring the relation V2≦V1<V3, stabilizes bulk density and prevents toner concentration increases by managing toner feeding amounts through the use of first and second screws with specific pitch relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the second conveying screw length is increased to cram toner into the toner conveying section, then toner concentration stability is improved, but rotation torque requirement increases and toner adhesion to blades occurs
Solution Approach 1:
The screw blade pitch is made non-uniform along the conveying direction, with different pitch values in different sections. Specifically, the pitch in the upstream section is smaller than the pitch in the downstream section, creating local variations in conveying characteristics that prevent toner adhesion while maintaining concentration stability.
Solution Approach 2:
The screw blade pitch parameter is changed along the conveying direction to optimize toner conveying. By varying the pitch from upstream to downstream sections, the system achieves stable toner concentration without requiring excessive rotation torque, preventing the vicious cycle of increasing torque and toner adhesion.
2Ease of operation
If the screw pitch is increased to reduce rotation torque, then ease of operation is improved, but toner conveying efficiency decreases
Solution Approach 1:
Different sections of the screw have different pitch values optimized for their specific functions. The upstream section with smaller pitch ensures efficient toner pickup and initial conveying, while the downstream section with larger pitch reduces resistance and facilitates smooth toner discharge, achieving both efficiency and ease of operation.
Solution Approach 2:
The screw pitch is designed to vary dynamically along the conveying direction rather than being uniform. This dynamic pitch distribution allows the screw to adapt its conveying characteristics at different positions, optimizing both torque requirements and conveying efficiency throughout the entire toner transport path.
3Stability of the object's composition
If toner is crammed into the toner conveying section to eliminate gaps, then toner feeding stability is improved, but pressure on toner increases causing concentration increase and adhesion
Solution Approach 1:
The screw pitch is optimized locally at different positions to achieve appropriate toner filling without excessive cramming. The varying pitch creates different conveying intensities in different sections, ensuring stable toner feeding while preventing excessive pressure that would lead to concentration increase and blade adhesion.
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 ensures stable toner supply, reduces pressure during conveyance, and prevents toner adhesion, thereby avoiding rotation lockages and image defects, ensuring consistent toner delivery to the developing apparatus.
Implementation Method 1
a screw which is provided in the toner conveying passage and which conveys the toner in the toner conveying passage toward the developing apparatus
Implementation Method 2
toner supplied from a toner cartridge 201 drops into a buffer portion 202 by gravity
Data Source
AI summary
A toner conveying apparatus comprising: a toner conveying member which discharges toner outside a toner accommodating portion; toner conveying passage which receives toner discharged from the toner accommodating portion; and a screw constituted such that a pitch in its region downstream in the toner conveying direction is wider than a pitch in its region upstream in the toner conveying direction; and a drive device which drives the toner conveying member and the screw; wherein if a toner feeding amount per unit drive time of the toner conveying member is defines as V1, and a toner feeding amount per unit drive time in the region of the screw upstream in the toner conveying direction is defined as V2, and a toner feeding amount per unit drive time in the region of the screw downstream in the toner conveying direction is defined as V3, a relation equation of V2≦V1<V3 is satisfied.