Lighting Device Uniform Illuminance Sandwich Structure
Solution Overview
Problem
Conventional lighting devices in image forming apparatuses, such as copiers and scanners, face challenges in providing uniform illuminance distribution, especially when dealing with thick documents or books, due to the point-source nature of LED light sources and the complexity of precise positioning required for multiple light sources.
Innovation Solution
A lighting device design featuring a light source sandwiched between a first and second sandwiching member, with reflection members and a positioning mechanism, ensures uniform light distribution by aligning LED packages straight in the main scanning direction and reflecting light from both sides in the sub-scanning direction, maintaining a stable light supply and simplifying maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a single LED point source is used for illumination, then the light source structure is simple and energy consumption is low, but the illuminance distribution on the document surface is non-uniform
Solution Approach 1:
The lighting device is divided into multiple independent LED modules, each with its own light guide member. These modules are arranged in series along the main scanning direction, with each module responsible for illuminating a specific segment of the document surface. This segmentation allows the system to achieve uniform illuminance distribution across the entire document while keeping each individual module structurally simple and easy to manufacture.
2Illumination intensity
If multiple light sources are added to improve illuminance uniformity, then the illuminance distribution improves, but the positioning precision requirement increases and maintenance becomes more difficult
Solution Approach 1:
By dividing the lighting system into modular LED modules that can be independently assembled and replaced, the design enables easy maintenance. If one module fails or requires adjustment, only that specific module needs to be accessed or replaced, not the entire lighting system. This modular approach significantly improves ease of repair while maintaining uniform illuminance distribution.
Solution Approach 2:
The positioning member automatically positions the LED modules at precise intervals along the main scanning direction without requiring complex external positioning mechanisms. This self-positioning capability ensures consistent illuminance uniformity while simplifying assembly and maintenance operations.
3Illumination intensity
If light sources are positioned precisely relative to guide members, then proper illuminance distribution is achieved, but the device complexity and positioning difficulty increase
Solution Approach 1:
A positioning member is introduced as an intermediary component between the LED modules and the light guide members. This positioning member provides standardized positioning features that automatically ensure correct relative positioning when modules are assembled, eliminating the need for high-precision manual positioning during manufacturing or assembly.
Solution Approach 2:
The modular design with integrated positioning features allows LED modules to self-position at correct intervals along the main scanning direction during assembly. This self-positioning mechanism ensures consistent illuminance uniformity without requiring complex external positioning systems or high manufacturing precision.
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 achieves uniform illuminance distribution across the document, preventing shading issues with thick documents and simplifying maintenance by allowing easy access and replacement of components, while maintaining a stable light supply and improved precision.
Implementation Method 1
The reflection member is provided on the first opposed surface of the first sandwiching member and the second opposed surface of the second sandwiching member to reflect the light emitted by the light source toward an irradiation region on an original document sheet
Data Source
AI summary
In a lighting device, a light source emits light. A second sandwiching member includes a second opposed surface opposing a first opposed surface of a first sandwiching member. The first sandwiching member and the second sandwiching member sandwich the light source in such a manner that the light source is detachably attached to the first sandwiching member and the second sandwiching member. A reflection member is provided on the first opposed surface of the first sandwiching member and the second opposed surface of the second sandwiching member to reflect the light emitted by the light source toward an irradiation region on an original document sheet. A positioning member is provided in the first opposed surface of the first sandwiching member and the second opposed surface of the second sandwiching member to position the light source with respect to the reflection member.