Print Head Grounding Arm for Image Forming Apparatus

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Solution Overview

Problem

Existing image forming apparatuses face challenges in efficiently grounding the print head during both image formation and maintenance, particularly in ensuring secure electrical connection and preventing load application when the print head is separated from the image forming unit.

Innovation Solution

An image forming apparatus with an electrically conductive frame, a print head, a holder, an electrically conductive urging member, and an arm that floats when separated but contacts and connects to the frame when the print head is in contact with the image forming unit, utilizing a spring property contact to ensure grounding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the print head is separated from the image forming unit during maintenance, then cleaning and replacement can be performed, but the grounding connection may be lost or damaged

Engineering Contradiction:
Improvemaintenance accessibilityVSAvoidgrounding connection reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The grounding connection transitions from a static fixed connection to a dynamic flexible connection. The arm can move between contacting and non-contacting states with the frame, allowing the print head to be separated during maintenance while maintaining grounding when in the imaging position. This dynamic adaptability resolves the contradiction between maintenance accessibility and grounding reliability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The electrical connection parameter changes based on the print head position. When the print head is in the imaging position, the arm contacts the frame to establish an electrical connection. When separated for maintenance, the connection is naturally broken. This parameter change allows the system to adapt to different operational states, resolving the contradiction.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a fixed grounding connection is used between the print head and frame, then grounding reliability is improved, but load and stress are applied to the connection during separation

Engineering Contradiction:
Improvegrounding connection reliabilityVSAvoidconnection durability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The grounding connection is made dynamic through the movable arm that can contact or separate from the frame. This eliminates continuous mechanical stress on the connection, as the arm only engages when needed for grounding during imaging. The connection durability is improved by avoiding constant load application while maintaining grounding reliability during operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The grounding connection is extracted from a permanent fixed state to a temporary engaged state. The arm serves as a take-out mechanism that provides grounding only when the print head is in the imaging position, removing the unnecessary continuous mechanical load that would otherwise be applied to a fixed connection during maintenance operations.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If the arm is always in contact with the frame, then grounding is maintained, but the arm cannot float when the print head is separated

Engineering Contradiction:
Improvegrounding connectionVSAvoidarm positioning mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The arm provides self-service grounding functionality through its own weight and elastic deformation. When the print head is in the imaging position, the arm naturally contacts the frame to establish grounding without requiring additional actuators or positioning mechanisms. The arm's own physical properties enable it to perform the grounding function, simplifying the overall device complexity while maintaining reliable grounding.

Inventive Principle:
Principle #25Self-service

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 solution ensures secure grounding of the print head during image formation and prevents load application during maintenance by using an electrically conductive arm that connects to the frame when the print head is in contact, maintaining efficient operation and preventing damage.

Implementation Method 1

an electrically conductive urging member between the print head and the holder that urges the print head toward the image forming unit

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the arm contacts the contact and is electrically connected to the frame when the print head contacts the image forming unit

Methodology Applied
Scientific EffectElectrical Conduction: Conduction (electrical)

Data Source

PatentEP3862817B1Image forming apparatus
Publication Date: 2024.03.20 TOSHIBA TEC KK
  • EP3862817B1 patent drawingFigure 1
  • EP3862817B1 patent drawingFigure 2
  • EP3862817B1 patent drawingFigure 3

AI summary

According to one embodiment, an image forming apparatus includes an electrically conductive and grounded frame, an image forming unit, a print head, a holder that supports the print head, an electrically conductive urging member between the print head and the holder for urging the print head toward the image forming unit, and an electrically conductive arm extending from the urging member and electrically connected to the urging member. The arm floats when the print head moves away from the image forming unit and is electrically connected to the frame when the print head contacts the image forming unit.