Optical Scanning Housing Ribs Reduce Vibration

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Solution Overview

Problem

Optical scanning apparatuses face challenges in maintaining rigidity and reducing vibrations, leading to image defects such as color deviation, particularly when trying to minimize the overall height of image forming apparatuses, as increased rigidity from stacked return mirrors and reduced housing thickness compromise image quality.

Innovation Solution

An optical scanning apparatus with two rotatable polygonal mirrors and a housing fixed to the frame using three attachment appendages, positioned such that the rotational axes form a triangular area, minimizing vibrations and deformation while maintaining image accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the housing is reduced in rigidity to reduce overall height, then the apparatus becomes more compact, but the beam of light misses preset points on the drum surface due to vibrations

Engineering Contradiction:
Improveoverall heightVSAvoidbeam positioning accuracy
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent applies local quality by providing reinforcement ribs at specific locations within the housing where vibrations occur most intensely. These ribs are strategically positioned to stiffen the housing structure locally without increasing the overall height of the apparatus, thus maintaining compactness while improving beam positioning accuracy.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces reinforcement ribs that extend in the height direction (vertical dimension) within the housing structure. This dimensional approach allows the ribs to effectively counteract vibrations caused by the rotating polygonal mirror without increasing the horizontal footprint or overall height of the apparatus.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If stacked return mirrors are used to guide beams, then the optical path is achieved, but the housing rigidity increases causing vibrations that affect image quality

Engineering Contradiction:
Improveoptical path configurationVSAvoidvibrations
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by providing reinforcement ribs at specific locations within the housing where vibrations occur most intensely. These ribs are strategically positioned to stiffen the housing structure locally without increasing the overall height of the apparatus, thus maintaining compactness while improving beam positioning accuracy.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent converts the harmful vibrations generated by the stacked return mirrors and rotating polygonal mirror into a design opportunity by strategically placing reinforcement ribs that leverage the vibration patterns to provide structural support exactly where needed, transforming the vibration problem into a solution for structural optimization.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Volume of moving object

If the housing thickness is reduced to make the apparatus compact, then the overall size decreases, but the housing deforms under vibration causing color deviation

Engineering Contradiction:
Improvehousing thicknessVSAvoidhousing deformation
Core Design Contradiction:
Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by providing reinforcement ribs at specific locations within the housing where vibrations occur most intensely. These ribs are strategically positioned to stiffen the housing structure locally without increasing the overall height of the apparatus, thus maintaining compactness while improving beam positioning accuracy.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs composite construction by combining the housing material with strategically placed reinforcement ribs, creating a composite structure that achieves high stiffness-to-weight ratio. This allows the housing to resist vibration-induced deformation and maintain dimensional stability for accurate color registration.

Inventive Principle:
Principle #40Composite materials

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

The solution reduces the amount of beam deviation caused by vibrations, maintains image quality, and allows for a more compact design by minimizing housing deformation and vibrations, thus enhancing the performance and size reduction of image forming apparatuses.

Implementation Method 1

a first deflection unit configured to deflect the beam emitted from the first light source, the first deflection unit including a first rotatable polygonal mirror configured to reflect the beam emitted from the first light source

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3575850B1Optical scanning apparatus and image forming apparatus
Publication Date: 2022.12.28 CANON KK
  • EP3575850B1 patent drawingFigure 1
  • EP3575850B1 patent drawingFigure 2
  • EP3575850B1 patent drawingFigure 3

AI summary

An optical scanning apparatus includes an optical scanning unit which includes a first light source, a first rotatable polygonal mirror for reflecting the beam emitted from the first light source, a second light source, a second rotatable polygonal mirror for reflecting the beam emitted from the second light source; and a housing accommodating the polygonal mirrors. The housing includes only three fixed portions fixed to a fixing portion for fixing the optical scanning unit. The first rotatable polygonal mirror and the second rotatable polygonal mirror are disposed such that a rotational axis of the first rotatable polygonal mirror and a rotational axis of the second rotatable polygonal mirror are in a triangular area defined by lines connecting the three fixed portions, as viewed in a rotation axial direction of the first rotatable polygonal mirror.