Printer Line Feed Error Calculation Using Dual Sensors
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Solution Overview
Problem
Current label printers lack the capability to determine and correct line feed errors, which affects print registration and overall print quality due to variations in instantaneous feed errors between the Label Stop Sensor and the Thermal Print Head.
Innovation Solution
A method and system that utilize a holder assembly with a first and second sensor, positioned at a fixed distance, to sense the position of a label's edge or optical feature, calculate the line feed error, and apply a correction by calculating the difference between the fixed distance and the sensed distance, with the processor instructing the printer to implement the necessary feed correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If line feed error correction is not implemented, then the system remains simple, but print registration accuracy deteriorates
Solution Approach 1:
The system performs preliminary measurement of the label's actual position using two sensors before the printing operation. Based on this preliminary measurement, the controller calculates the line feed error and adjusts the burn line position in advance, ensuring accurate print registration without requiring complex real-time correction mechanisms during printing.
Solution Approach 2:
The system uses feedback from two position sensors that detect the actual location of label features (edge, gap, or black mark). The controller compares the sensed positions with the expected positions, calculates the line feed error, and uses this feedback information to correct the burn line position, creating a closed-loop control system that maintains print registration accuracy.
2Manufacturing precision
If instantaneous feed error is not corrected, then the system operates simply, but print quality deteriorates
Solution Approach 1:
The system replaces complex mechanical correction mechanisms with an electronic/software-based solution. The controller uses software algorithms to calculate line feed error from sensor data and electronically adjusts the burn line position through digital signal processing, eliminating the need for complex mechanical adjustment devices while maintaining high print quality.
Solution Approach 2:
The system introduces an intermediary computational layer between the physical label feed mechanism and the printing process. The controller acts as an intermediary that receives position data from sensors, processes this information through error calculation algorithms, and translates it into corrected positioning signals for the burn line, thereby decoupling the mechanical feed system from the printing precision requirements.
3Measurement precision
If label position is not monitored, then the system operates quickly, but print registration accuracy deteriorates
Solution Approach 1:
The system uses two sensors instead of one to monitor label position, providing redundant measurement data that improves accuracy. The sensors detect the label's position at two different points, allowing the controller to calculate more precise line feed error values. This partial excess in sensing capability delivers superior position accuracy without significantly increasing processing time.
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 accurate print registration by continuously calculating and correcting line feed errors, improving the quality of printed images on labels by maintaining precise alignment with the printer's burn line.
Implementation Method 1
sensing a position of a first edge of the label, L1A, by the first sensor as the label moves over the first sensor; sensing a second position of the first edge of the label, L1B, by the second sensor as the label moves over the second sensor
Data Source
AI summary
A system to calculate line feed error in labels on a printer includes a holder assembly under the label line feed and before the printer burn line; a first sensor and a second sensor on the holder assembly, a fixed distance, L, between them; and a processor. The first sensor senses a first position of a label edge, L1A. The second sensor senses a second position of the label edge, L1B. The processor calculates the distance, L1AB, between the first position and the second position and calculates the line feed error over the fixed distance, L, by taking the difference (L−L1AB). The processor calculates the feed correction to be done to the label, given by [(L−L1AB)/L]×D, where D is a distance between the first sensor and the burn line of the printer. The processor instructs the printer line feed to implement the calculated feed correction.