Resin Regulating Blade Rib Mounting for Image Stability
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Solution Overview
Problem
The existing developing devices with resin-made regulating blades face fluctuations in the SB gap due to thermal stress and developer pressure, leading to instability in image formation, as the resin blades are prone to deformation and have limited rigidity, especially when fixed to a resin-made developing device frame.
Innovation Solution
A developing device with a resin-made regulating blade that is flexed and fixed to a resin-made developing device frame, where the frame's mounting portion includes a rib extending along the rotational axis direction, enhancing the geometrical moment of inertia and rigidity, thereby stabilizing the SB gap within a predetermined range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the rigidity of the regulating blade is enhanced by increasing thickness, then the SB gap stability is improved, but sink marks are more likely to generate and manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by providing ribs only in the maximum image region of the blade mounting portion rather than uniformly increasing the thickness of the entire blade mounting portion. This localized reinforcement increases the geometrical moment of inertia and rigidity where it is most needed (at the ribet portion) while avoiding excessive thickness elsewhere, thereby preventing sink mark generation during molding while still achieving the required SB gap stability.
2Strength
If ribs are provided in the maximum image region of the blade mounting portion, then the geometrical moment of inertia is increased and rigidity is enhanced, but thermal stress causes distortion in the direction parallel to the rotational axis
Solution Approach 1:
The patent applies asymmetry by orienting the ribs in a specific direction (parallel to the rotational axis of the developer carrying member) rather than uniformly in all directions. This asymmetric rib arrangement provides the necessary rigidity enhancement in the critical direction (perpendicular to the rotational axis where SB gap stability is needed) while allowing controlled thermal stress distribution that minimizes distortion in the parallel direction, thus resolving the contradiction between rigidity enhancement and thermal distortion.
3Strength
If the thickness of the blade mounting portion is increased to enhance rigidity, then the SB gap stability is improved, but cooling time and cycle time during molding become longer
Solution Approach 1:
The patent applies local quality by concentrating the structural reinforcement through ribs only in the maximum image region where SB gap stability is critical, rather than uniformly increasing the thickness of the entire blade mounting portion. This localized approach significantly enhances the geometrical moment of inertia at the ribet portion with minimal additional material, thereby maintaining high rigidity while keeping the overall component thickness low, which allows for shorter cooling times and faster molding cycles, thus improving productivity.
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
The solution effectively suppresses fluctuations in the SB gap due to thermal stress and developer pressure, ensuring consistent image formation by increasing the rigidity of the blade mounting portion and maintaining the SB gap within a predetermined range, enhancing the overall stability and accuracy of the image forming process.
Implementation Method 1
the mounting portion is provided with a rib extending in a direction parallel to the rotational axis direction of the developer carrying member over an entirety of a region of the mounting portion corresponding to a maximum image region of the image bearing member
Implementation Method 2
when a resin material thermal expanded during molding is thermally contracted, a degree of generation of a difference in progress of thermal contraction between an inside and an outside of the resin mold product is liable to become large
Implementation Method 3
when a resin material thermal expanded during molding is thermally contracted, a degree of generation of a difference in progress of thermal contraction between an inside and an outside of the resin mold product is liable to become large
Implementation Method 4
a developer pressure generating from a flow of a developer is exerted on a regulating blade in a region (maximum image region of a regulating blade) corresponding to a maximum image region of an image region in which an image is formed on an image bearing member
Data Source
AI summary
A developing device includes a rotatable developing member, a resin-made regulating blade, and a resin-made developing device frame including at least a mounting portion. The regulating blade is fixed, in a state that the regulating blade is flexed, in a region of the mounting portion corresponding to a maximum image region of an image bearing member so that a gap between the rotatable developing member and the regulating blade falls within a predetermined range over a rotational axis direction of the rotatable developing member. The mounting portion is provided with a rib which includes a portion projecting from the mounting portion and extending along a direction parallel to the rotational axis direction of the rotatable developing member and which is formed over an entirety of a region of the mounting portion corresponding to the maximum image region of the image bearing member.