Magnetic Coupling Structure for Misaligned Developing Roller Shafts

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Solution Overview

Problem

Existing image forming apparatuses face challenges in maintaining reliable power transmission between misaligned shafts of the developing roller and print engine, particularly when switching between alienated and non-alienated states, which can lead to power transmission issues and potential damage from excessive forces.

Innovation Solution

The implementation of a magnetic coupling structure with inclined interlocking drive elements and a magnetically attracted design allows for self-alignment and torque transmission between misaligned shafts, enabling reliable power transfer in both coaxial and non-coaxial configurations while disengaging under excessive force conditions to prevent damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a magnetic coupling structure is used to transmit power between misaligned shafts, then power transmission reliability is improved, but device complexity increases due to the addition of magnetic coupling components

Engineering Contradiction:

Improvepower transmission reliabilityVSAvoidcoupling structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical coupling elements (keys, splines, or direct shaft connections) with a magnetic coupling system. Magnets are embedded in the developing roller assembly to create magnetic fields that transmit rotational force to the print engine shaft without physical contact, enabling reliable power transmission while accommodating misalignment between shafts.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The magnetic field acts as an intermediary between the two misaligned shafts. Instead of requiring direct mechanical contact, the magnetic coupling structure transmits torque through the magnetic field, which can accommodate positional deviations and misalignment while maintaining effective power transmission.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If rigid coupling elements are used to ensure precise alignment, then alignment precision is improved, but the risk of damage from excessive force increases

Engineering Contradiction:

Improveshaft alignment precisionVSAvoiddamage from excessive force

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical state of the coupling from rigid mechanical connection to flexible magnetic field interaction. The magnetic coupling allows for parameter variations in shaft position and alignment while maintaining functional connection, preventing the transmission of excessive forces that would occur with rigid mechanical couplings under misalignment conditions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The magnetic coupling inherently provides a cushioning effect by allowing the magnetic field to slip or deform under excessive force conditions. This prevents the transmission of damaging peak forces to the shafts and connected components, acting as a protective mechanism before damage can occur.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Stability of the object's composition

If fixed coupling structures are used to maintain stable connection, then connection stability is improved, but adaptability to misalignment conditions deteriorates

Engineering Contradiction:

Improveconnection stabilityVSAvoidadaptability to misalignment

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent transforms the static, fixed coupling structure into a dynamic magnetic field-based connection. The magnetic coupling can adapt its field distribution and strength based on the relative position of the shafts, maintaining stable power transmission while accommodating various degrees of misalignment that would be impossible with fixed mechanical couplings.

Inventive Principle:

Principle #15Dynamics

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 ensures reliable power transmission and proper alignment of the developing roller, reducing wear and extending its lifespan, while preventing damage from over-torque conditions, thus enhancing the operational efficiency and durability of the image forming apparatus.

Implementation Method 1

a magnet disposed in the body to cause the coupling structure to be attracted to the another coupling structure so that the coupling structure is aligned with the another coupling structure

Methodology Applied

Scientific EffectMagnetic attraction: Magnetism

Data Source

PatentUS11927909B2Magnetic coupling structure for an image forming apparatus

Publication Date: 2024.03.12 HEWLETT PACKARD DEVELOPMENT COMPANY LP

AI summary

An image forming apparatus includes a development cartridge having a developing roller. A coupler for the image forming apparatus includes a shaft and a coupling structure to rotate the developing roller. The coupling structure is disposed at an end part of the shaft, is movable along an axial direction of the shaft and coupleable with another coupling structure of a print engine of the image forming apparatus. The coupling structure includes a body, a magnet disposed in the body to cause the coupling structure to be attracted to the another coupling structure so that the coupling structure is aligned with the another coupling structure, and a plurality of protrusions which protrude from the body in the axial direction to engage with the another coupling structure, the plurality of protrusions having at least one side with an inclined face.