Development Cartridge Shaft Coupling for Uniform Roller Rotation

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Solution Overview

Problem

The rotation uniformity of photosensitive and developer rollers in development cartridges is inconsistent, affecting the quality of printed images due to gear connection structures that can introduce jitters and positional instability.

Innovation Solution

The development cartridges are designed with a shaft connection method where the photosensitive drum and developer roller are individually connected to the main body's driver, eliminating gear connections to ensure stable and uniform rotation, with a driven coupler and bearing portion supporting the photosensitive drum and developer roller for precise alignment and rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a gear connection structure is used to connect the photosensitive drum and developer roller, then the structure can provide mechanical drive, but the rotation uniformity deteriorates due to gear-induced jitters and positional instability

Engineering Contradiction:
Improverotation uniformityVSAvoidgear-induced jitters
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent removes the gear connection structure from the drive system. Instead of using gears to connect the photosensitive drum and developer roller, the invention directly drives both components without mechanical gear interfaces, thereby eliminating the source of jitters and rotation instability that gears inherently introduce.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical gear connection system with a direct drive mechanism. By substituting the gear-based mechanical transmission with a direct coupling approach, the system eliminates the harmful mechanical interactions that cause rotation non-uniformity while maintaining the necessary drive functionality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If a gear connection structure is used to connect the photosensitive drum and developer roller, then the structure can transmit rotational motion, but the image quality deteriorates due to unstable positioning

Engineering Contradiction:
Improveimage formation capabilityVSAvoidpositioning accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent extracts and removes the gear connection structure that causes positioning instability. By eliminating the gear mechanism, the system achieves more stable positioning of the photosensitive drum and developer roller, which directly improves image quality by preventing registration errors and positioning variations during image formation.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If a shaft connection method is used to individually connect the photosensitive drum and developer roller to the driver, then the rotation uniformity improves, but the device complexity increases

Engineering Contradiction:
Improverotation uniformityVSAvoidconnection structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the drive system by providing separate direct drive connections for the photosensitive drum and developer roller. Instead of using a single complex gear system to drive both components, the invention divides the drive into independent direct-drive units, simplifying each connection while improving overall rotation uniformity.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3690548B1Electrophotographic image forming apparatus
Publication Date: 2022.01.26 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3690548B1 patent drawingFigure 1
  • EP3690548B1 patent drawingFigure 2
  • EP3690548B1 patent drawingFigure 3

AI summary

Disclosed is a development cartridge attachable/detachable to/from a main body of an image forming apparatus. The development cartridge includes a photosensitive drum configured to form an electrostatic latent image thereon, a developer roller configured to develop the electrostatic latent image by supplying a developer to the photosensitive drum, a housing configured to support the photosensitive drum and the developer roller, a developer roller gear provided on a rotation shaft of the developer roller and connected to a driving gear of the main body when the development cartridge is attached to the main body, and a driven coupler provided at an end of the photosensitive drum and connected to a driving coupler located coaxially with the driving gear in the main body, based on a shaft connection method when the development cartridge is attached to the main body.