Printer Door Hinge Assembly with Four-Bar Linkage for Controlled Access

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Solution Overview

Problem

Conventional printer designs often expose internal components when the door is opened, which can lead to a larger operational footprint and unsafe user interaction, as they fail to effectively conceal critical parts while allowing access to replaceable cartridges.

Innovation Solution

A hinge assembly with a four-bar linkage mechanism that maintains parallelism between the door and the printer housing, allowing the door to move through a controlled angle and intermediate positions, reducing exposure of internal components and simplifying access by using a synchronized pair of hinge assemblies with a cross-bar and torque-damping pins.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the door is opened to allow access to internal components, then user access to replaceable cartridges is improved, but internal components become exposed creating safety hazards and increasing operational footprint

Engineering Contradiction:
ImproveAccess to replaceable cartridgesVSAvoidExposure of internal components
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The door opening motion is segmented into multiple stages through the four-bar linkage mechanism. The door first rotates downward to an intermediate position (exposing only the cartridge access area), then can be fully opened if needed. This segmentation allows selective exposure - users can access cartridges without fully exposing all internal components, thus reducing safety hazards while maintaining ease of cartridge replacement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The four-bar linkage mechanism provides dynamic control over the door's position and orientation throughout the opening motion. The linkage dynamically adjusts the door's trajectory to maintain parallelism between the door and housing during rotation, and can control the door to stop at intermediate positions. This dynamic control enables the system to balance between providing access and concealing internal components.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If the door opens fully to maximize access, then ease of operation is improved, but the operational footprint and space requirements increase

Engineering Contradiction:
ImproveDoor accessibilityVSAvoidOperational footprint
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

The four-bar linkage mechanism changes the dimensionality of the door's motion path. Instead of a simple arc rotation that would require significant lateral space, the linkage guides the door through a controlled trajectory that combines rotation with constrained movement. This dimensional control allows the door to open to necessary angles for access while maintaining a compact operational footprint and preventing the door from extending beyond the printer's footprint.

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

3Device complexity

If a simple hinge mechanism is used for door rotation, then device complexity is reduced, but the ability to control door position and maintain parallelism is worsened

Engineering Contradiction:
ImproveHinge mechanismVSAvoidDoor position control
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent merges multiple functions into the four-bar linkage mechanism: it provides the hinge function for rotation, adds position control through the linkage geometry, maintains parallelism between door and housing, and enables intermediate stopping positions. While this increases device complexity compared to a simple hinge, it consolidates multiple control requirements into a single integrated mechanism rather than requiring separate systems for each function.

Inventive Principle:
Principle #5Merging (Combining)

4Object-affected harmful factors

If the door is designed to conceal all internal components when open, then safety is improved, but access to replaceable cartridges is worsened

Engineering Contradiction:
ImproveConcealment of internal componentsVSAvoidAccess to cartridges
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The door opening motion is segmented into multiple stages through the four-bar linkage mechanism. The door first rotates downward to an intermediate position (exposing only the cartridge access area), then can be fully opened if needed. This segmentation allows selective exposure - users can access cartridges without fully exposing all internal components, thus reducing safety hazards while maintaining ease of cartridge replacement.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3448687B1Printer door hinge assembly
Publication Date: 2022.06.01 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3448687B1 patent drawingFigure 1A~1C
  • EP3448687B1 patent drawingFigure 2A~2C
  • EP3448687B1 patent drawingFigure 3

AI summary

A printer includes a housing, a print engine within the housing, a door to cover a portion of the housing, and a hinge assembly coupled to the housing and the door to support the door in a closed position to cover the portion of the housing and an open position to uncover the portion of the housing, wherein, in the open position, the door is offset from the housing by the hinge assembly.