Image forming apparatus

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Solution Overview

Problem

The challenge of further downsizing image forming apparatuses is hindered by limited space for installing fans and ducts, making it difficult to adopt conventional noise reduction methods like multiple ducts with different lengths or side branches to reduce air current noise effectively.

Innovation Solution

The implementation of a noise reduction duct configuration that merges air currents without using a side branch, utilizing a sirocco fan to manage airflow efficiently while reducing noise through a duct design that minimizes space requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If multiple ducts having different lengths or ducts with side branches are used to reduce air current noise, then noise reduction is achieved, but device size increases

Engineering Contradiction:
Improveair current noiseVSAvoidduct configuration space
Core Design Contradiction:
Object-affected harmful factorsVSVolume of stationary object

Solution Approach 1:

The single duct is segmented into multiple air passages within its structure. The duct body includes partition walls that divide the internal space into multiple passages, allowing noise reduction through multiple paths without requiring multiple separate ducts. This segmentation achieves noise interference effects while maintaining a compact single-duct external form.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple air passages are nested within the single duct body structure. The partition walls create internal passages that are contained within the outer duct housing, effectively nesting multiple functional paths inside one physical component. This allows the duct to perform multiple noise reduction functions without occupying additional space.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Volume of stationary object

If a compact duct configuration is used to downsize the apparatus, then device size is reduced, but noise reduction capability is lost

Engineering Contradiction:
Improveduct configuration spaceVSAvoidair current noise
Core Design Contradiction:
Volume of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The duct configuration is optimized locally by creating specific partition wall arrangements and passage geometries within the compact duct body. The partition walls are positioned and dimensioned to create effective noise interference patterns at specific locations, allowing noise reduction to occur locally within the compact structure rather than requiring extended duct lengths.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The noise reduction function is achieved by adding the dimensional complexity of internal partition structures within the single duct body. Instead of extending the duct in linear dimensions to create multiple separate ducts, the invention uses internal three-dimensional partitioning to create multiple passages, effectively utilizing vertical and lateral dimensions within the compact duct housing.

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

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 approach effectively reduces air current noise, allowing for a more compact image forming apparatus design without compromising airflow efficiency or increasing pressure loss.

Implementation Method 1

a noise absorbing member (715) attached to the outer surface (730b) of the holed wall portion (730) so as to cover the plurality of through holes (711), the noise absorbing member (715) having a noise absorbing property

Methodology Applied
Scientific EffectAcoustic absorption: Acoustic Absorption

Data Source

PatentEP4254073B1Image forming apparatus
Publication Date: 2026.05.06 CANON KK
  • EP4254073B1 patent drawingFigure 1
  • EP4254073B1 patent drawingFigure 2A~2B
  • EP4254073B1 patent drawingFigure 3

AI summary

An image forming apparatus includes an image forming unit (500), a fan, a duct (710) including an air intake port (720), an air discharge port (721), and a body portion (740) forming an air passage, the body portion (740) including a holed wall portion (730) to which a plurality of through holes (711) are formed, the plurality of through holes (711) being passed through between an inner surface (730a), forming the air passage, of the holed wall portion (730) and an outer surface (730b), that is on an opposite side from the inner surface (730a), of the holed wall portion (730), and a noise absorbing member (715) attached to the outer surface (730b) of the holed wall portion (730) so as to cover the plurality of through holes (711), the noise absorbing member (715) having a noise absorbing property.