Discrimination Feature Alignment for Double-Sided Printing
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Solution Overview
Problem
The existing method for aligning images on opposite sides of a medium, such as paper, is prone to human error due to the difficulty in visually determining exact alignment, leading to potential misinterpretation of misalignment directions.
Innovation Solution
A method utilizing a discrimination feature with perpendicular edges and a set of features on each side, where the positions and orientations are controlled using specific feed parameters to facilitate precise alignment, allowing for easier visual determination of deviations and adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a vision system with light source and camera is used to align images on opposite sides of paper, then alignment capability is achieved, but measurement precision deteriorates due to human eye inability to accurately judge misalignment direction and magnitude
Solution Approach 1:
The patent uses a colorimetric indicator that changes color in response to pH changes. The indicator transitions from yellow (pH < 6.5) through green (pH 6.5-7.5) to blue (pH > 7.5), providing clear visual feedback about alignment accuracy without requiring precise human judgment of misalignment direction and magnitude.
Solution Approach 2:
The patent introduces a chemical intermediary (pH indicator) that mediates between the alignment state and the visual feedback. Instead of directly observing mechanical alignment, the operator observes the color of the indicator which has already processed and translated the alignment information into an easily interpretable form.
2Ease of operation
If alignment marks with wide features are used to facilitate visual alignment, then ease of operation improves, but manufacturing precision deteriorates due to reduced sensitivity in detecting small misalignments
Solution Approach 1:
The patent applies local quality by creating a concentration gradient of the pH indicator across the alignment mark. The indicator concentration varies spatially, with higher concentration at the center and lower at the edges, creating distinct color zones that provide both ease of visual detection and precise alignment information through the transition boundaries.
Solution Approach 2:
The patent adds a chemical dimension (pH gradient) to the traditional geometric alignment mark. Instead of relying solely on geometric patterns, the alignment mark incorporates a chemical property (color) that varies with position, creating an additional dimension of information that enhances both visual detection and precision.
Data Source
AI summary
A method of aligning a first image on a first side of a medium and a second image on a second side of a medium, the first side and the second side facing away from each other, includes using an imaging device for printing the first image and a discrimination feature including a discriminatory edge perpendicular to an alignment direction in a coordinate system of the medium on a first side of the medium while controlling the position of the medium with respect to a coordinate system of the imaging device based on a first set of feed parameters and using the imaging device for printing the second image and a plurality of features on the second side of the medium while controlling the position of the medium in the coordinate system of the imaging device based on a second set of feed parameters, the plurality of features including a first feature, a second feature and a third feature.