Optical Print Head Linkage Mechanism Alignment

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Solution Overview

Problem

Existing image forming apparatuses lack a simple structure for preventing the inclination of optical print heads, which is essential for ensuring proper movement and contact with the drum unit during maintenance, leading to potential damage to the optical print head and photosensitive drum.

Innovation Solution

A moving mechanism with a link mechanism that suppresses rotation of the third link portion, allowing the first and second springs to deform and impart an urging force towards the exchange unit, ensuring proper alignment and movement of the optical print head.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the optical print head is retracted from the exposure position during exchange unit replacement, then the risk of contact damage is reduced, but the optical print head may incline and fail to move properly, compromising reliability

Engineering Contradiction:
Improvecontact damage riskVSAvoidmovement reliability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent changes the spatial parameters of the optical print head by introducing a retraction mechanism that moves the print head from the exposure position to a retracted position during exchange unit replacement. This parameter change (position) reduces contact damage risk while the linkage mechanism ensures the print head maintains proper alignment throughout the movement, preserving movement reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent makes the optical print head dynamic by enabling it to move between fixed positions (exposure and retracted) through a linkage mechanism. This dynamic capability allows the system to adapt to different operational states: retracted during maintenance to avoid damage, and positioned for exposure during normal operation, thus resolving the contradiction between safety and reliability.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If a moving mechanism is added to retract the optical print head, then contact damage is prevented, but the device complexity increases

Engineering Contradiction:
Improvecontact damage riskVSAvoidmechanism complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the retraction function with the existing exchange unit replacement operation. The linkage mechanism is integrated into the overall system architecture, sharing structural elements and control logic with the exchange unit mounting/dismounting mechanism. This merging approach enables the retraction function without proportionally increasing device complexity, as the mechanism leverages existing system resources.

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If the optical print head is kept at the exposure position for precise alignment, then imaging precision is maintained, but the risk of contact damage during maintenance increases

Engineering Contradiction:
Improveimaging precisionVSAvoidcontact damage risk
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by retracting the optical print head before the exchange unit replacement process begins. This preemptive retraction prevents contact damage from occurring in the first place. After the exchange unit is safely replaced, the print head is returned to the exposure position to restore imaging precision, thus resolving the contradiction between precision and safety through temporal separation of operations.

Inventive Principle:
Principle #10Preliminary action

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 effectively prevents the inclination of the optical print head, ensuring safe and reliable movement between exposure and retracted positions, thereby reducing the risk of damage to the optical print head and photosensitive drum during maintenance.

Implementation Method 1

a first spring and a second spring which are different from each other in terms of a spring constant, the first link portion and the second link portion being deformable by urging forces of the first spring and the second spring, respectively

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3640741B1Image forming device equipped with optical print head
Publication Date: 2022.11.30 CANON KK
  • EP3640741B1 patent drawingFigure 1
  • EP3640741B1 patent drawingFigure 2(a)~2(b)
  • EP3640741B1 patent drawingFigure 3

AI summary

An image forming apparatus includes a third link portion which is rotatably connected to said first link portion at a position between said first connecting portion and said first moving portion so that said first moving portion and said second moving portion are moved toward said drum unit by rotation of said first link portion about said first connecting portion as a rotation shaft and by rotation of said second link portion about said second connecting portion as a rotation shaft in interrelation with slide of said slidable portion, and which is rotatable relative to the apparatus main assembly. The third link portion is out of contact with the optical print head at a portion corresponding to an end portion on the optical print head side.