Exposure Unit Mounting Structure for Vibration-Stable Image Forming

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Solution Overview

Problem

Existing electrophotographic image forming apparatuses face issues with vibration of the exposure unit, which can lead to image defects, and there is a need for downsizing and reducing weight while maintaining structural integrity.

Innovation Solution

The image forming apparatus incorporates a frame body with metal plate stays and support members to securely fix the exposure unit, using a resin fixing attachment for flexibility and metal support members for rigidity, along with wire springs to reduce vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the exposure unit is fixed to a metal plate stay with high rigidity, then vibration of the exposure unit is reduced, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improveexposure unit vibration reductionVSAvoidframe structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The frame structure is divided into resin plate frames for general support and metal plate stays for specific vibration-critical support. This segmentation allows the complex vibration reduction function to be achieved through a modular approach, where only specific components require high rigidity while others can use lighter resin materials.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite frame structure combining resin plates and metal plate stays. The resin plate frames provide general structural support while metal plate stays provide localized high rigidity support for the exposure unit, creating a composite structure that optimizes both weight and vibration resistance.

Inventive Principle:
Principle #40Composite materials

2Weight of stationary object

If the image forming apparatus is downsized and weight is reduced, then installation space and production cost are reduced, but structural integrity and vibration resistance deteriorate

Engineering Contradiction:
Improveapparatus weightVSAvoidvibration resistance
Core Design Contradiction:
Weight of stationary objectVSReliability

Solution Approach 1:

Instead of making the entire frame heavy and rigid, the invention applies metal plate stays only at specific locations where vibration resistance is critical (near the exposure unit), while other parts of the frame can use lighter resin materials. This local quality approach maintains vibration resistance without unnecessarily increasing overall weight.

Inventive Principle:
Principle #3Local quality

3Weight of stationary object

If resin plate frames are used instead of metal frames, then weight and cost are reduced, but rigidity and vibration resistance deteriorate

Engineering Contradiction:
Improveframe weightVSAvoidframe rigidity
Core Design Contradiction:
Weight of stationary objectVSStrength

Solution Approach 1:

The frame is segmented into resin plate frames for general support and metal plate stays for critical support. This allows the system to benefit from both lightweight resin construction and high-rigidity metal support where needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention creates a composite frame system combining resin and metal materials, where each material is used in the locations where its properties are most beneficial, optimizing the balance between weight reduction and rigidity requirements.

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

This configuration effectively reduces exposure unit vibration, preventing image defects and allows for a more compact and lightweight design.

Implementation Method 1

wire springs to reduce vibration

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

wire springs to reduce vibration

Methodology Applied
Scientific EffectVibration damping: Damping

Data Source

PatentEP4198636B1Image forming apparatus
Publication Date: 2026.03.25 CANON KK
  • EP4198636B1 patent drawingFigure 1
  • EP4198636B1 patent drawingFigure 2
  • EP4198636B1 patent drawingFigure 3

AI summary

An image forming apparatus includes an image bearing member (11), a frame member (75) including a support surface (751) and made of metal, an exposure unit (50) disposed such that an emission direction in which the light is emitted to the image bearing member (11) is inclined with respect to the support surface (751), a support member (83A) made of metal and configured to support the exposure unit (50) that is in an inclined posture with respect to the support surface (751), and a positioning member (84) made of resin and configured to be in contact with the exposure unit (50) and position the exposure unit (50). The support surface (751) of the frame member (75) is in contact with at least one of the support member (83A) or the positioning member (84), and wherein the exposure unit (50) is configured to be attached to the frame member (75) via the support member (83A) and the positioning member (84).