Developing Device Light Reflection Gap Adjustment
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Solution Overview
Problem
Existing methods for adjusting the gap between the developer carrying member and the layer thickness regulating member in image forming apparatuses face challenges in accuracy and stability, particularly during mass production and when transitioning from an unfinished to a finished state, due to variations in surface properties and material reflectivity, leading to potential image defects.
Innovation Solution
A developing device with a light-transmitting portion in the upper cover allows for precise measurement of the gap between the developer carrying member and the layer thickness regulating member by regularly reflecting light from the rotation shaft, enabling high-accuracy adjustment through the detection of exiting reflected light, even after assembly, without the need for additional reflection members or separate light-transmitting components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light reflection method is used to measure gap between developing sleeve and developing blade, then gap measurement can be performed, but measurement accuracy largely depends on surface property, surface treatment and material, causing reflected light intensity to vary remarkably depending on measuring condition
Solution Approach 1:
A light-transmitting member is introduced as an intermediary component between the light source and the gap measurement area. This member transmits light to the gap region and reflects it back, serving as a stable optical mediator that is not affected by the surface properties of the developing sleeve or blade. The light-transmitting member provides consistent reflection characteristics, enabling stable and accurate gap measurements regardless of variations in the surface properties of other components.
2Manufacturing precision
If dimensional tolerance of developing sleeve, developing blade and positioning component is required to have very high accuracy, then gap control is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent replaces mechanical dimensional tolerance control with an optical measurement and adjustment system. Instead of relying on precisely manufactured components with tight dimensional tolerances, the invention uses light transmission and reflection through the light-transmitting member to measure and adjust the gap. This optical approach substitutes complex mechanical precision requirements with a more flexible measurement-based adjustment method.
3Ease of operation
If gap adjustment is performed in unfinished state as disclosed in JP-A 2011-150102, then adjustment operativity is improved, but error generates between gap in unfinished state and finished state due to rigidity difference
Solution Approach 1:
The patent enables gap adjustment to be performed in the unfinished state using the light-transmitting member as a reference, which remains stable across different states. The light-transmitting member is positioned and configured in advance to provide consistent optical reference points that can be used for measurement in both unfinished and finished states, eliminating the rigidity-related errors that plague conventional adjustment methods.
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 high-accuracy gap adjustment between the developer carrying member and the layer thickness regulating member, enhancing image quality by maintaining precise control over the developer coating amount, reducing image defects, and simplifying the manufacturing process by improving measurement stability and reducing costs.
Implementation Method 1
a light-transmitting portion (83a), provided in the upper cover portion (83), for permitting light transmission to an inside of the developing container (84)
Implementation Method 2
when a light beam entering the inside of the developing container (84) is regularly reflected by a surface of a rotation shaft (49ay)
Data Source
AI summary
A developing device includes a developing container for accommodating a developer, a rotatable developer carrying member for carrying and feeding the developer, and a layer thickness regulating member for regulating a layer thickness of the developer carried on the developer carrying member. The developer circulates between first and second chambers, which are partitioned by a partition wall. A rotatable feeding member feeds the developer in the first chamber, and a light-transmitting portion permits light transmission into a developing container. The light-transmitting portion is disposed at a developer carrying member side of the partition wall so that a light beam entering inside of the developing container is regularly reflected by a surface of a rotation shaft of the feeding member, and the regularly reflected light is emitted outside of the developing container through a gap between the developer carrying member and the layer thickness regulating member.