Developing Device Seal Pressing Mechanism for Toner Leakage Prevention
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Solution Overview
Problem
Conventional developing devices for electro-photographic printers face issues with sufficient pressure contact between the blade side seal and the developing roller, leading to toner leakage due to gaps between the seal and the roller.
Innovation Solution
A developing device with a frame, a developing agent carrying member, a layer thickness regulator, and a pair of first seals, where the layer thickness regulator includes a first plate member and a second plate member to fix the first plate member to the frame, and the first seals are positioned between the axial end portion of the developing agent carrying member and the layer thickness regulator, with a projecting portion from the second plate member pressing the first seal toward the developing agent carrying member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the blade side seal is urged to be in pressure contact with the developing roller only by the urging force of the leaf spring member, then the construction remains simple, but sufficient pressure contact cannot be attained and toner leakage occurs
Solution Approach 1:
The blade side seal is divided into two functional parts: a sealing portion for preventing toner leakage and a pressing portion for receiving urging force. This segmentation allows the sealing portion to be optimized for contact stability while the pressing portion handles the mechanical force application, resolving the contradiction between seal effectiveness and construction simplicity.
Solution Approach 2:
The leaf spring member and the blade side seal are combined into an integrated structure where the leaf spring member provides both the urging force and part of the sealing function. This merging eliminates the need for separate sealing components while maintaining effective pressure contact, thus improving reliability without significantly increasing complexity.
2Reliability
If a stronger urging force is applied to the blade side seal to prevent gaps, then toner leakage is prevented, but the seal and blade member deform due to excessive force
Solution Approach 1:
The blade side seal has different local properties: the sealing portion is designed to be softer for conforming to the developing roller surface and maintaining stable contact, while the pressing portion is structurally reinforced to withstand urging forces without deformation. This local differentiation allows effective sealing with moderate forces, preventing both leakage and structural damage.
Solution Approach 2:
The leaf spring member provides dynamic urging force that automatically adjusts to maintain optimal pressure contact. The spring's elastic properties allow it to compensate for variations in roller surface and seal position, maintaining reliable sealing without applying excessive static force that would cause deformation.
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 contact between the first seal and the developing roller, preventing toner leakage while maintaining a simple structure, and provides improved mechanical strength and reduced deformation of the seals and blade member.
Implementation Method 1
The second plate member has a projecting portion projecting therefrom in the particular direction and pressing the first seal toward the developing agent carrying member
Data Source
AI summary
A developing device is capable of preventing developing agent from leaking from a developing frame of a developer cartridge. The developer cartridge includes a developing agent carrying member, a layer thickness regulator, and a first seal positioned between the developing agent carrying member and the layer thickness regulator. The regulator includes a plate member provided with a projecting portion. The projecting portion has a laterally outer end portion positioned inward of laterally outer end portion of the first seal.