Unit Moving Device for Image Formers

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Solution Overview

Problem

Existing unit moving devices for image forming apparatuses require significant operational force and complexity, leading to degraded operability and increased cost due to the use of motors or high-strength springs, especially with heavy sheet feeding cassettes and image forming portions.

Innovation Solution

A unit moving device utilizing a tension spring and roller mechanism that guides the sheet feeding cassette into position using a combination of inclined guides and pulleys, allowing for automatic and effortless mounting and removal without the need for motor-driven systems, leveraging the elastic force of the tension spring for reliable positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a motor-driven driving unit is used to force the sheet feeding cassette to be pulled to the normal mounting position, then the sheet feeding cassette can be reliably positioned, but the structure becomes complex and the size and cost of the apparatus increase

Engineering Contradiction:
Improvepositioning reliabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the motor-driven mechanical system with a spring-based elastic force system. The elastic member (spring) is configured to automatically urge the sheet feeding cassette to the normal mounting position when the cassette is pulled out, eliminating the need for complex motor-driven mechanisms while maintaining positioning reliability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The elastic member provides self-service functionality by automatically generating the necessary force to return the sheet feeding cassette to its normal mounting position without requiring external power sources or control systems. The spring mechanism self-activates based on the displacement of the cassette

Inventive Principle:
Principle #25Self-service

2Reliability

If a spring having a large elastic force is used to pull the sheet feeding cassette to the normal mounting position, then the positioning reliability improves, but a larger operational force is required and operability is degraded

Engineering Contradiction:
Improvepositioning reliabilityVSAvoidoperability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies local quality by providing the elastic member only at the specific location where it is needed to urge the sheet feeding cassette, rather than using a uniform high-force mechanism throughout. The spring is positioned to engage only when the cassette is displaced, providing force locally at the point of need

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The elastic member is designed to provide just enough force to return the cassette to the normal mounting position under normal operating conditions. The spring force is calibrated to be sufficient for typical cassette weights but not excessively strong, balancing positioning reliability with ease of operation

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If the amount of sheets loaded in the sheet feeding cassette is increased to decrease the number of times of replenishment, then the work efficiency improves, but the total weight of the sheet feeding cassette increases

Engineering Contradiction:
Improvework efficiencyVSAvoidcassette weight
Core Design Contradiction:
ProductivityVSWeight of moving object

Solution Approach 1:

The patent changes the parameter of spring force to accommodate varying cassette weights. The elastic member is designed with adjustable or variable force characteristics that can handle both lightweight cassettes with few sheets and heavyweight cassettes filled to capacity, ensuring reliable positioning across the full weight range

Inventive Principle:
Principle #35Parameter changes

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 enables reliable and efficient mounting of units within the image forming apparatus with reduced operational force, maintaining simplicity and cost-effectiveness while ensuring accurate positioning and reduced wear on components.

Implementation Method 1

a tension spring, which pulls the sheet feeding cassette to a normal mounting position in a main body of an apparatus when the sheet feeding cassette is mounted in the main body of the apparatus

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

a roller, which moves along an inclined guide when the sheet feeding cassette is mounted in the main body of the apparatus

Methodology Applied
Scientific EffectFriction reduction: Roller

Data Source

PatentEP2638433B1Unit moving device and image forming apparatus
Publication Date: 2019.07.17 CANON KK
  • EP2638433B1 patent drawingFigure 1A~1B
  • EP2638433B1 patent drawingFigure 2A~2B
  • EP2638433B1 patent drawingFigure 3~4A

AI summary

A roller is rotatably provided in an arm that is swingable relative to a main body of an apparatus, and is connected to a tension spring using a wire of a roller shaft. A roller guide portion that guides the roller is provided in a sheet feeding cassette. The roller is guided along a guiding member of the roller guide portion in accordance with insertion of the sheet feeding cassette into the main body of the apparatus. When the roller is guided along the guiding member, an elastic force of the tension spring is accumulated. The sheet feeding cassette is pulled to a mounting position when the roller is guided along the guiding member. The sheet feeding cassette is pushed out also when the roller is guided along the guiding member.