Fluorescent Registration Stripe for Thermal Printer Alignment
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Solution Overview
Problem
Existing color direct thermal printing methods face challenges in accurately aligning repeating patterns of color dyes with the print head, leading to inefficiencies and inaccuracies in color printing.
Innovation Solution
The use of direct thermal media with a regular repeating pattern of thermally-imageable stripes, combined with an optical registration system and image processing unit, synchronizes the printing process by detecting the position of fluorescent stripes using an anamorphic optical system and solid-state sensors, ensuring precise alignment and registration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If ribbons with multiple color dyes are used for color printing, then color printing capability is achieved, but alignment accuracy of repeating patterns deteriorates
Solution Approach 1:
A fluorescent registration stripe is introduced as an intermediary element between the color dyes and the print head detection system. This fluorescent stripe emits light when excited by UV illumination, creating a high-contrast optical signal that serves as a reliable mediator for detecting the position of the repeating pattern, thereby improving alignment accuracy without compromising color printing capability
Solution Approach 2:
The invention utilizes fluorescent color change properties by incorporating a fluorescent material into the registration stripe. When exposed to UV light from the illumination source, the fluorescent material absorbs and re-emits light at a different wavelength, creating a visually distinct and optically detectable signal that enhances the detectability of the repeating pattern position for precise alignment
2Device complexity
If conventional optical detection methods are used, then simplicity is maintained, but detection precision of stripe pattern position deteriorates
Solution Approach 1:
The fluorescent registration stripe exploits fluorescence color change under UV excitation to create a high-contrast optical signal. This natural optical phenomenon enhances the detectability of the stripe pattern position without requiring complex detection hardware, maintaining system simplicity while significantly improving measurement precision
Solution Approach 2:
The invention changes the optical parameters of the registration stripe by incorporating fluorescent material that alters its light emission characteristics under UV illumination. This parameter change transforms the stripe into a self-highlighting feature that can be detected with higher precision using standard optical sensors, improving measurement precision without substantially increasing device complexity
3Manufacturing precision
If registration patterns are added to improve alignment, then alignment accuracy is improved, but media complexity increases
Solution Approach 1:
The registration function is segmented from the color printing function by placing the fluorescent registration stripe in a separate location from the color dye patterns. This segmentation allows the registration stripe to serve its alignment purpose independently while the color dyes handle color printing, improving alignment accuracy without substantially complicating the overall media structure
Solution Approach 2:
The fluorescent registration stripe acts as an intermediary element that facilitates alignment detection without interfering with the color printing process. Its simple fluorescent property provides a clear optical signal for position detection, improving alignment accuracy while maintaining relatively simple media construction
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 enables precise alignment and synchronization of the printing process, resulting in improved color accuracy and consistency across printed items such as documents, receipts, and labels, while minimizing the impact of printing defects and media skew.
Implementation Method 1
one stripe set also contains a fluorophore and is fluorescent under excitation light of a defined wavelength range
Implementation Method 2
an anamorphic optical system and solid-state sensors, synchronizes the printing process by detecting the position of fluorescent stripes using an anamorphic optical system
Implementation Method 3
filter and focus the emitted fluorescence light pattern by the fluorescent stripe as an image on an a sensor
Data Source
AI summary
An example disclosed media processing device includes an image processing unit; a first optical registration sensor; and a second optical registration sensor spaced apart from the first optical registration sensor along a first axis by a first distance associated with a gap between media units on a web.