Light Scanning Unit with Synchronization Path
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light scanning units in electrophotographic image forming apparatuses face challenges in achieving a long focal length while maintaining stable optical performance, as larger effective thicknesses of optical components are difficult to manufacture precisely and are sensitive to environmental conditions, leading to potential image quality deterioration.
Innovation Solution
A light scanning unit design with a polygonal mirror and an fθ lens that includes a synchronization detecting optical path before the imaging lens, allowing for a total scanning rate of 60% to 75% and an effective scanning rate of 60% to 70%, which restricts the increase in effective thickness, enabling the production of long-focal-length units without unnecessary increases in component size or manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the focal length L is increased to extend developing unit lifespan, then the developing unit can contain more toner and be replaced less frequently, but the effective thickness D increases in proportion to L, making precise manufacturing difficult and increasing sensitivity to environmental conditions
Solution Approach 1:
The patent changes the optical parameters by introducing a telecentric lens system with specific focal length ratios (f2/f1 between 0.3-0.7) and configuring the optical path so that the effective thickness D does not increase proportionally with focal length L. This parameter optimization allows achieving long focal length (94.2mm or 132mm) while maintaining manufacturable effective thickness (1.9mm or 2.5mm) through precise optical design rather than simple linear scaling.
2Length of stationary object
If the effective thickness D is increased to achieve longer focal length, then the focal length L increases, but optical components become more sensitive to environmental conditions such as temperature, increasing the possibility of image quality deterioration
Solution Approach 1:
The patent optimizes the optical parameters by using a telecentric lens configuration where the effective thickness D is decoupled from the focal length L through specific focal length ratios (f2/f1 between 0.3-0.7). This allows achieving long focal length (94.2mm or 132mm) while maintaining manageable effective thickness (1.9mm or 2.5mm), thereby reducing environmental sensitivity and improving image quality stability.
3Length of stationary object
If optical components with larger effective thickness are manufactured, then the focal length can be increased, but it is very difficult to manufacture precise optical components having a large effective thickness using plastic injection molding
Solution Approach 1:
The patent changes the manufacturing parameters by optimizing the focal length ratio (f2/f1 between 0.3-0.7) and optical path configuration to achieve long focal length (94.2mm or 132mm) with manageable effective thickness (1.9mm or 2.5mm). This optimized parameter set falls within the manufacturable range for plastic injection molding, making precise optical component production feasible while maintaining long focal length requirements.
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 allows for a stable long-focal-length light scanning unit that can be manufactured without significant increases in effective thickness, enhancing the toner capacity of developing units and reducing maintenance costs by extending their lifespan.
Implementation Method 1
a polygonal mirror deflecting light emitted from the light source in a main scanning direction
Implementation Method 2
an imaging lens transmitting the deflected light to a photoconductor for forming an image
Data Source
AI summary
Provided are a light scanning unit and an electrophotographic image forming apparatus including the light scanning unit. The light scanning unit includes a light source, a polygonal mirror deflecting light emitted from the light source in a main scanning direction, an imaging lens transmitting the deflected light to a photoconductor for forming an image, and a synchronization detecting unit detecting a synchronization signal from the deflected light for synchronization in the main scanning direction. The light scanning unit has a total scanning rate, including a synchronization detecting optical path, ranging from about 60% to 75%.