Developing Apparatus Third Screw Agitation Toner Density
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Solution Overview
Problem
Conventional developing apparatuses face issues with partial non-uniformity and decrease in toner density during high coverage rate image formation, as the developer collected from the developing sleeve is not sufficiently agitated and mixed with replenished toner before being resupplied, leading to uneven density distribution.
Innovation Solution
A developing apparatus with a third conveying screw in the collection chamber, arranged to convey the developer in a direction opposite to the second conveying screw, and positioned with a spiral blade around its rotary shaft, is used to effectively agitate and distribute the developer reduced in toner density, ensuring it is adequately mixed with replenished toner before being resupplied to the developing sleeve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the developer collected from the developing sleeve is immediately resupplied to the developing sleeve after being collected in the developing apparatus, then the productivity is improved, but the toner density distribution becomes non-uniform and decreases
Solution Approach 1:
The patent introduces a collection chamber that temporarily stores the developer after collection from the developing sleeve, preventing immediate resupply. This preliminary storage action allows time for toner density to be replenished and uniformized before the developer is transferred back to the supply chamber, thus resolving the contradiction between productivity and toner density stability.
2Quantity of substance
If a toner is replenished to compensate for consumed toner, then the toner density is maintained, but the replenished toner is not sufficiently mixed with the collected developer, causing partial non-uniformity in toner density
Solution Approach 1:
The collection chamber acts as an intermediary space between the supply chamber and the developing sleeve. In this intermediate zone, replenished toner can be thoroughly mixed with the collected developer before the mixture is transferred back to the supply chamber, ensuring uniform toner density distribution while maintaining the required toner quantity.
3Stability of the object's composition
If the developer is circulated between the supply chamber and collection chamber using conveying screws, then the toner density is equalized, but the level of the developer rises toward the downstream side, reducing agitation effectiveness
Solution Approach 1:
The patent positions the third conveying screw specifically at the downstream side of the collection chamber where the developer level rises. This localized intervention creates enhanced agitation precisely where the developer tends to stagnate, ensuring thorough mixing in the critical high-level region without disrupting the overall circulation pattern.
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 uniform toner density distribution, preventing the developer from being immediately conveyed to the supply chamber without sufficient agitation, thereby maintaining consistent image quality even during high coverage rate printing.
Implementation Method 1
a magnet configured to cause the developer carrying member to carry the developer
Implementation Method 2
a first conveyance member provided in the supply chamber and configured to convey the developer in the supply chamber; a second conveyance member provided in the collection chamber and configured to convey the developer in the collection chamber
Data Source
AI summary
A developing apparatus includes a developer carrying member configured to carry a developer including a toner and a carrier, a supply chamber provided opposite to a peripheral surface of the developer carrying member, and a collection chamber provided opposite to the peripheral surface of the developer carrying member. In addition, a first conveyance member is provided in the supply chamber, a second conveyance member is provided in the collection chamber, and a third conveyance member is provided opposite to the second conveyance member. The third conveyance member and the second conveyance member are directly opposed to each other in a predetermined position which overlaps with a developer carrying area of the developer carrying member, and the third conveyance member conveys a part of the developer conveyed by the second conveyance member in the predetermined position in the direction opposite to the second conveyance member.