Optical Writing Device Positioning for Thermal Expansion

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Solution Overview

Problem

Conventional optical writing devices experience deterioration in optical performance due to positional displacement of the scanning optical member in the optical axis direction, caused by thermal expansion differences between the scanning optical member and the casing, leading to peeling and deformation of the adhesive and subsequent changes in the scanning optical member's position.

Innovation Solution

The optical writing device incorporates a scanning optical member with a linear expansion coefficient different from the casing, featuring optical axis direction positioners that protrude and contact the scanning optical member, along with a main-scanning direction positioner to stabilize the scanning optical member's position, using thick-film bonding with an adhesive that contracts upon curing to manage thermal expansion and reduce tensile forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the scanning optical member is bonded to the casing with adhesive to fix its position, then the optical performance is improved, but the adhesive peels and deforms due to thermal expansion differences, causing positional displacement

Engineering Contradiction:

Improvepositioning precision of scanning optical memberVSAvoidbonding reliability of adhesive

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The invention divides the positioning function into separate components: positioners for optical axis direction positioning and a separate main-scanning direction positioner. This segmentation allows each component to handle specific thermal expansion effects independently, preventing adhesive deformation while maintaining positioning precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The positioners act as intermediary elements between the scanning optical member and the casing. These positioners absorb the thermal expansion differences and prevent direct transmission of stress to the adhesive, thereby maintaining bonding reliability while ensuring precise positioning.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If positioners are provided to fix the scanning optical member in the optical axis direction, then the positioning is improved, but the structure becomes more complex

Engineering Contradiction:

Improvepositioning precision in optical axis directionVSAvoidstructure complexity of positioning system

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention merges the optical axis direction positioning function with the existing adhesive bonding structure. The positioners are integrated into the casing design, and their central positions in the sub-scanning direction are strategically located to overlap with bonding positions, combining multiple functions into a unified structure that reduces overall complexity.

Inventive Principle:

Principle #5Merging (Combining)

3Strength

If thick-film bonding is used to suppress peeling due to thermal expansion, then the bonding strength is improved, but the adhesive still deforms under thermal stress

Engineering Contradiction:

Improvebonding strength of adhesiveVSAvoidstability of adhesive under thermal stress

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The positioners are designed in advance to counteract the thermal expansion effects before they can cause adhesive deformation. By providing mechanical support and constraint through the positioners, the adhesive is protected from thermal stress-induced deformation, maintaining both bonding strength and compositional stability.

Inventive Principle:

Principle #9Preliminary anti-action

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 suppresses changes in the scanning optical member's position and improves optical performance by minimizing the impact of thermal expansion on the adhesive and scanning optical member, maintaining stable optical performance even under temperature variations.

Implementation Method 1

the scanning optical member has a linear expansion coefficient different from a linear expansion coefficient of the casing

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

using thick-film bonding with an adhesive that contracts upon curing to manage thermal expansion and reduce tensile forces

Methodology Applied

Scientific EffectThermal contraction: Thermal Contraction

Data Source

PatentUS10635015B1Optical writing device and image forming device

Publication Date: 2020.04.28 KONICA MINOLTA INC

AI summary

An optical writing device includes a light source, a deflector, an imager, and a casing, wherein the imager includes a scanning optical member, the casing includes an optical axis direction positioner, the optical axis direction positioner includes two one side positioners, and one other side positioner, a central position in a sub-scanning direction of the one other side positioner is located between central positions in the sub-scanning direction of the two one side positioners, the scanning optical member is bonded to the casing at a bonding position, and a position in the sub-scanning direction of the bonding position and a position in the sub-scanning direction of the optical axis direction positioner overlap with each other, a main-scanning direction positioner is further provided, and the main-scanning direction positioner is located on the other side with respect to the central position of the scanning optical member in the main-scanning direction.