Exposure Head Bonding Layout for Thermal Expansion Control
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Solution Overview
Problem
In exposure heads used in electrophotographic image forming apparatuses, thermal expansion differences due to heat generation affect optical characteristics, and relying solely on heat dissipation members is insufficient to prevent deformation of substrates and lens arrays.
Innovation Solution
The exposure device incorporates a housing support member bonded with different hardness adhesives at each end, supporting the housing and substrate, and utilizes airflow cooling to manage thermal expansion and maintain optical precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the housing support member is fixed to the housing to secure strength, then assembly ease and positioning are improved, but deformation due to thermal expansion difference may induce deformation of the substrate and lens array, affecting optical characteristics
Solution Approach 1:
The bonding is segmented into two distinct adhesive applications: a first adhesive with higher hardness for the one end requiring strong fixation, and a second adhesive with lower hardness for the other end needing thermal expansion accommodation. This segmentation allows each end to have optimized properties for its specific functional requirement.
Solution Approach 2:
Different adhesive hardnesses are applied at different locations (ends) of the housing support member based on local requirements. The one end uses harder adhesive for strength, while the other end uses softer adhesive for flexibility, creating local quality variations that resolve the contradiction between overall strength and local thermal expansion management.
2Temperature
If a cooling mechanism is introduced to cool the substrate, then temperature rise is reduced, but device complexity increases
Solution Approach 1:
The housing support member acts as an intermediary element that provides passive thermal management. By bonding the housing to the support member with appropriate adhesives, the system leverages the support member's thermal properties and the adhesive layer's thermal characteristics to dissipate heat without requiring active cooling components.
Solution Approach 2:
The housing support member and adhesive combination provides self-service cooling through passive heat dissipation. The thermal expansion difference management and heat dissipation occur automatically through the material properties and bonding configuration, eliminating the need for external cooling mechanisms.
3Loss of energy
If only a heat dissipation member is used, then heat dissipation is improved, but it is insufficient to prevent deformation of substrate and lens array
Solution Approach 1:
The system uses a composite structure combining the housing, housing support member, and adhesive materials with different thermal expansion properties. This composite material approach allows the assembly to manage thermal stress through the coordinated deformation characteristics of each material layer, preventing deformation of critical components while maintaining heat dissipation.
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 effectively manages thermal expansion, maintaining optical characteristics and ensuring precise exposure by using a housing support member with varying adhesive hardness and airflow cooling.
Implementation Method 1
a thermal expansion difference occurs in the exposure head such as the light emitting element, a lens array, and a housing that holds the light emitting element and the lens array due to heat generation of the substrate at the time of light emission
Implementation Method 2
one ends of the housing and the housing support member in a longitudinal direction are bonded with a first adhesive, the other ends of the housing and the housing support member in the longitudinal direction are bonded with a second adhesive
Implementation Method 3
a cooling mechanism for cooling the substrate is required
Data Source
AI summary
An exposure device includes a substrate on which a plurality of light emitting elements that emits light to expose the photosensitive member is arranged in the axial direction; a lens array configured to collect the light emitted from the light emitting elements on the photosensitive member; a housing configured to hold the substrate and the lens array; and a housing support member configured to support the housing. Ends of the housing and the housing support member in a longitudinal direction are bonded with a first adhesive, other ends of the housing and the housing support member in the longitudinal direction are bonded with a second adhesive, and a hardness of the first adhesive after curing is higher than a hardness of the second adhesive after curing.