Light Source Unit Asymmetric Adhesive for Focus Stability
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Solution Overview
Problem
The existing light source units in electrophotographic image forming apparatuses face issues with image quality due to shrinkage and deformation of the synthetic resin support body over time, causing changes in the focus position of laser light, which affects the quality of the electrostatic latent images formed on the photosensitive drums.
Innovation Solution
The light source unit incorporates a support body made of synthetic resin with integrally molded first and second support portions, where the collimator lens is fixed using an adhesive agent with a larger amount applied between the second support portion and the opposite side of the collimator lens, rather than between the collimator lens and the light source, to counteract the shrinkage and deformation, maintaining the distance between the collimator lens and the light source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a support body made of synthetic resin is used to support optical components, then ease of manufacture and device complexity are improved, but shrinkage and deformation occur over time causing deterioration of manufacturing precision and image quality
Solution Approach 1:
The patent applies parameter changes by strategically controlling the amount of adhesive agent applied to different surfaces of the collimator lens. Specifically, a larger amount of adhesive agent is applied to the second face (opposite the light source side) than to the first face (light source side). This asymmetric adhesive distribution creates compensatory stress that counteracts the shrinkage deformation of the synthetic resin support body, thereby maintaining the focus position accuracy despite the inherent deformation tendency of the resin material.
2Reliability
If adhesive agent is applied between support body and collimator lens, then reliability of component fixation is improved, but shrinkage deformation of adhesive agent causes change in distance between components
Solution Approach 1:
The patent applies asymmetry by creating an intentional asymmetric adhesive distribution pattern. A larger amount of adhesive agent is applied to the second face of the collimator lens compared to the first face. This asymmetric application generates uneven stress distribution in the adhesive layer that compensates for the shrinkage deformation, thereby maintaining the critical distance between the collimator lens and light source while still providing reliable component fixation.
3Ease of manufacture
If uniform adhesive agent application is used, then ease of manufacture is improved, but shrinkage stress causes deformation and deterioration of image quality
Solution Approach 1:
The patent applies local quality by creating different adhesive agent amounts at different locations on the collimator lens surfaces. Specifically, the second face (opposite the light source) receives a larger amount of adhesive agent compared to the first face (light source side). This localized variation in adhesive quality creates compensatory stress distribution that counteracts the shrinkage deformation, thereby maintaining distance stability while still being manufacturable through controlled adhesive application processes.
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 configuration stabilizes the position of the collimator lens relative to the light source, preventing changes in the focus position of the laser light and thus maintaining image quality over time by balancing the displacement caused by resin shrinkage and adhesive deformation.
Implementation Method 1
the collimator lens is fixed using an adhesive agent with a larger amount applied between the second support portion and the opposite side of the collimator lens, rather than between the collimator lens and the light source, to counteract residual stress-induced deformation
Data Source
AI summary
This light source unit includes a light source, a collimator lens, a support body, and an adhesive agent. The collimator lens is configured to collimate laser light emitted from the light source. In the support body, a first support portion configured to support the light source and a second support portion configured to support the collimator lens are integrally molded with each other by use of a synthetic resin. The adhesive agent is attached by a larger amount between the second support portion and a second face which is on an opposite side to a first face on the light source side of the collimator lens, than between the second support portion and the first face.