Sealing Member Thickness Gradient for Uniform Blade Contact Pressure
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Solution Overview
Problem
The existing development devices in image forming apparatuses often result in nonuniform image density due to uneven contact pressure across the lengthwise direction of the development blade, leading to inconsistent toner charging and image quality.
Innovation Solution
A development apparatus with a regulating member and sealing member where the sealing member's thickness is greater at the free end portion than the base end portion when compressed, ensuring uniform contact pressure and preventing toner leakage, thereby maintaining consistent toner charging across the development roller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the development blade is made to contact the development roller across its entire length, then uniform toner charging should be achieved, but nonuniform contact pressure causes nonuniform image density
Solution Approach 1:
The sealing member is designed with nonuniform thickness along the axial direction, being thicker at the end portions and thinner at the center portion. This local variation in thickness compensates for the nonuniform contact pressure distribution, ensuring that the development blade maintains consistent contact pressure with the development roller across its entire length, thereby achieving uniform image density.
Solution Approach 2:
The invention changes the geometric parameter (thickness) of the sealing member along its length to compensate for pressure distribution variations. By making the sealing member thicker at the ends and thinner at the center, the effective contact pressure is equalized across the development blade length, resolving the nonuniformity issue.
2Ease of manufacture
If the sealing member is made thinner to reduce complexity, then manufacturing is easier, but toner leakage prevention becomes insufficient
Solution Approach 1:
The sealing member employs nonuniform thickness distribution, being thicker at the end portions where toner leakage is more likely to occur and thinner at the center portion. This local variation provides enhanced sealing capability at critical locations while maintaining overall structural simplicity and ease of manufacture.
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 design reduces nonuniformity in image density by ensuring consistent contact pressure along the development blade, resulting in improved image quality and uniformity across the image forming apparatus.
Implementation Method 1
said sealing member having an elasticity
Data Source
AI summary
A developing apparatus for an image forming apparatus includes a frame having a developer container; a developing roller; a blade for regulating a developer layer thickness on the roller, the blade including a base end portion supported by the frame, and a free end portion contacted to the roller; and an elastic seal provided between the frame and the blade to prevent leakage of the developer from the developer container in an axial direction of the roller at an end portion, wherein in a state before the roller is mounted to the frame, a thickness of the seal, measured in a compression direction in which the seal is compressed by the blade, is larger in a free end portion side than in a base end portion side with respect to a direction crossing with the axial direction.