Wrap Spring Clutch Auger Torque Transmission
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Solution Overview
Problem
The existing drive shaft-auger arrangements in printer cartridges face challenges with secure coupling and cost, particularly with metal drive shafts being expensive and plastic drive shafts struggling to transmit sufficient torque for effective waste toner removal.
Innovation Solution
A secure coupling mechanism is achieved through a drive shaft with an outer diameter greater than the auger's inner diameter, allowing a non-slip engagement that eliminates the need for additional coupling components, using a plastic drive shaft with a metal auger for efficient waste toner removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal drive shaft is used to connect the auger with its drive source, then the auger can be securely attached without additional coupling components, but the cost increases significantly
Solution Approach 1:
The patent combines the drive shaft and auger into a single integrated component made from metal wire stock. The auger is formed directly on the drive shaft as a continuous structure, eliminating the need for separate coupling mechanisms and reducing assembly steps while maintaining secure attachment.
Solution Approach 2:
The patent uses metal wire stock to form both the drive shaft and auger components, creating a composite structure that provides both structural integrity and secure attachment capability. The metal material offers strength and rigidity while allowing for cost-effective manufacturing compared to using separate metal and plastic components.
2Ease of manufacture
If a plastic drive shaft is used to reduce cost, then manufacturing cost decreases and assembly simplifies, but the torque transmission capability is insufficient for effective waste toner removal
Solution Approach 1:
The patent employs metal wire stock to construct the drive shaft, providing the necessary strength and rigidity for effective torque transmission. The metal material ensures sufficient force transmission to rotate the auger and effectively move waste toner, while the integrated design keeps manufacturing costs reasonable.
Solution Approach 2:
The patent forms the auger with a helical curved structure directly on the drive shaft. This curved geometry is essential for the auger's function of conveying waste toner along the channel, and the metal construction ensures the curved structure can withstand the mechanical stresses of torque transmission.
3Ease of manufacture
If injection molded plastic augers are used, then manufacturing is easier and drive shaft integration is simpler, but the augers cannot bend to transfer waste toner through curved channels
Solution Approach 1:
The patent forms the auger with a helical curved structure that can bend and adapt to curved channels. The metal wire construction allows the auger to flex and follow the curvature of the waste toner transfer path, enabling effective toner movement through non-linear channels while maintaining structural integrity.
Solution Approach 2:
The use of metal wire stock provides the necessary flexibility and strength combination, allowing the auger to bend into curved configurations while maintaining sufficient rigidity to convey waste toner effectively through the transfer channels.
4Adaptability or versatility
If metal wire augers are used, then the augers can bend during waste toner transfer and transfer toner through curved channels effectively, but a metal drive shaft is required which increases cost
Solution Approach 1:
The patent merges the drive shaft and auger into a single integrated metal wire structure. This combination eliminates the need for separate metal drive shaft and metal auger components, reducing material costs and manufacturing complexity while maintaining the bending capability needed for curved channel navigation.
Solution Approach 2:
The integrated metal wire construction provides both the structural integrity of a drive shaft and the bending capability of an auger in a single component, offering cost-effective manufacturing while maintaining adaptability for curved channel operation.
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 provides a cost-effective and reliable attachment between the auger and drive shaft, ensuring effective waste toner removal from the photoconductive drum to the waste toner compartment without additional components, enhancing the efficiency and reliability of the toner transfer process.
Implementation Method 1
When a torque is applied to rotate the drive shaft, the coils of the wrap spring clutch contract so the inner diameter of the auger more tightly engages with the outer diameter of the drive shaft. This substantially non-slip engagement between the auger and the drive shaft... Friction between the two surfaces prevents slip between the two surfaces.
Data Source
AI summary
An apparatus for moving waste toner within a printer cartridge includes an auger having a radially inward facing surface, the radially inward facing surface defining an opening having an inner diameter. An elongated drive shaft has an outer surface defining an outer diameter, the outer diameter of the drive shaft being greater than the inner diameter of the auger. The radially inward facing surface of the auger engages the outer surface of the drive shaft with a first pressure when the drive shaft is rotated within the opening of the auger in a first direction with a first load applied on the auger.