Optical Print Head Lens Array Mounting Precision

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Solution Overview

Problem

The existing optical print head designs face challenges in precisely adjusting the mounting position of the lens array relative to the holding member, leading to potential breakage and interference issues during assembly, which affects the image quality due to contamination from toner scattering.

Innovation Solution

The optical print head incorporates a gripping mechanism that holds both side wall surfaces of the lens array, allowing for precise adjustment and mounting between opposing portions, and uses an adhesive application method to securely attach the lens array to the holding member, preventing toner contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the lens array is held by a holding mechanism during mounting, then the lens array can be positioned, but there is a possibility of breakage and interference with the holding member

Engineering Contradiction:
Improvemounting position precisionVSAvoidrisk of breakage
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by providing preliminary positioning protrusions on the lens array that engage with positioning recesses on the holding member before final adhesive bonding. This preliminary mechanical positioning ensures accurate mounting position while preventing breakage during the assembly process, as the lens array is guided into place without requiring forceful insertion or complex holding mechanisms.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If the lens array is held with respect to the longitudinal direction, then positioning is easier, but the lens array may break

Engineering Contradiction:
Improvepositioning easeVSAvoidlens array strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent applies local quality by providing localized positioning protrusions at specific locations on the lens array rather than holding the entire lens array along its longitudinal direction. These positioning protrusions are strategically placed to engage with corresponding recesses on the holding member, providing sufficient positioning ease while minimizing the holding force required and reducing the risk of lens array breakage.

Inventive Principle:
Principle #3Local quality

3Device complexity

If the lens array is held with respect to the optical axis direction, then mounting is simplified, but there is interference with the holding member

Engineering Contradiction:
Improvemounting process complexityVSAvoidassembly efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent resolves this contradiction by implementing preliminary mechanical positioning through protrusion-recess engagement that simplifies the mounting process without causing interference. The positioning protrusions on the lens array fit into predetermined recesses on the holding member, establishing the correct optical axis alignment before adhesive application. This preliminary action eliminates the need for complex holding mechanisms while ensuring accurate positioning, thereby improving assembly efficiency.

Inventive Principle:
Principle #10Preliminary action

4Ease of manufacture

If there is a gap between the lens array and the holding member, then assembly is easier, but toner enters and contaminates the light emitting elements

Engineering Contradiction:
Improveassembly easeVSAvoidtoner contamination
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent applies the intermediary principle by introducing adhesive as a mediating substance between the lens array and the holding member. The adhesive fills the gap completely when applied, bonding the lens array to the holding member while preventing toner from entering the space between them. This intermediary substance achieves both goals: it allows for easy assembly during manufacturing while preventing harmful toner contamination during operation, thereby protecting the light emitting elements.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution enables precise adjustment and secure mounting of the lens array, reducing the risk of breakage and contamination, thereby improving image quality and maintaining the optical print head's performance during maintenance and operation.

Implementation Method 1

a mounting position of the lens array relative to the holding member is adjusted, and thereafter, the lens array and the holding member are adhesively fixed to each other

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

The plurality of lenses are disposed opposed to the surface of the photosensitive drum so as to extend along an arrangement direction of the light emitting elements between the light emitting elements and the photosensitive drum. The light beams emitted from the plurality of light emitting elements are concentrated on the surface of the photosensitive drum through the lenses.

Methodology Applied
Scientific EffectLight concentration through lenses: Lens

Data Source

PatentEP3640036B1Optical print head, image formation device, and optical print head manufacturing method
Publication Date: 2023.10.25 CANON KK
  • EP3640036B1 patent drawingFigure 1
  • EP3640036B1 patent drawingFigure 2(a)~2(b)
  • EP3640036B1 patent drawingFigure 3(a)~3(b)

AI summary

A holding member 505 of the present invention includes a first opposing portion (first inner wall surface) and a second opposing portion (second inner wall surface) which oppose side wall surfaces of a lens array 506. Side wall surfaces of the lens array on opposite end sides with respect to a longitudinal direction of the lens array are exposed from opposite ends of the first opposing portion and opposite ends of the second opposing portion.