Print Head Assembly Positioning via Lever and Lead Screw

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Solution Overview

Problem

Current methods for positioning print head assemblies in printer devices lack sufficient accuracy, which affects the quality of printed images due to inaccuracy in positioning droplets relative to each other.

Innovation Solution

A method utilizing a lever, coarse sensor, and lead screw mechanism with a fine sensor to determine precise positioning by detecting signals and adjusting distances between sensor detections, allowing for improved accuracy without requiring relative positioning of different sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a two-step positioning method (linear homing + rotary homing) is used, then the positioning process can be completed, but the positioning accuracy is insufficient

Engineering Contradiction:
Improvepositioning accuracyVSAvoidpositioning process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The positioning method is segmented into three distinct steps: coarse positioning using a lever and coarse sensor, intermediate positioning using a lead screw mechanism and fine sensor to detect first and second signals, and final positioning by calculating distances and selecting reference signals. This segmentation allows each step to address specific accuracy requirements without overwhelming system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The coarse positioning step using the lever and coarse sensor is performed preliminarily to bring the print head assembly close to the target position before the more precise lead screw mechanism is engaged. This preliminary action reduces the travel distance and improves the effectiveness of subsequent fine positioning steps.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If sensors are used to detect position, then positioning can be achieved, but sensor drift affects accuracy

Engineering Contradiction:
Improveposition detection accuracyVSAvoidsensor stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system uses feedback from the fine sensor to detect the positions of the first and second signals, calculates the actual distances traveled, compares them with predetermined distances, and selects the reference signal that minimizes the difference. This feedback mechanism compensates for sensor drift and maintains positioning accuracy.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The method dynamically changes the reference parameter (reference signal selection) based on the measured distances from the fine sensor. By selecting whichever reference signal (first or second) produces the smallest difference from the predetermined distance, the system adapts to sensor drift conditions and maintains optimal positioning accuracy.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3587131B1Printer device and method for positioning a print head assembly in a printer device
Publication Date: 2021.06.09 CANON PRODN PRINTING HLDG BV
  • EP3587131B1 patent drawingFigure 1
  • EP3587131B1 patent drawingFigure 2A~2C
  • EP3587131B1 patent drawingFigure 3A~3E

AI summary

The present invention relates to a method for positioning a print head assembly in a printer device. The invention also relates to a printer device configured for applying such method.