Optical Encoder Sensors for Print Media Misalignment Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current inkjet printing systems using continuous ink jet technology lack comprehensive tracking of print media, particularly in web-based systems, as they only monitor at one location, limiting information on print media location and failing to detect in-track and cross-track stretch.
Innovation Solution
A printing system equipped with at least two optical encoder sensors that measure displacement and velocity of the print media, providing output signals to a controller to control the print module operations, enabling detection of print media travel-direction shifts and distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single optical encoder is used to monitor print media, then the device complexity is reduced, but the measurement precision and information completeness about print media location and stretch is insufficient
Solution Approach 1:
The patent divides the monitoring function into multiple segments by using at least two optical encoders positioned at different locations along the print media path. Each encoder independently measures position and stretch at its specific location, providing segmented monitoring coverage that collectively delivers comprehensive measurement precision without requiring an overly complex unified system
2Device complexity
If monitoring is performed at only one location, then the device complexity is minimized, but the loss of information regarding in-track and cross-track stretch occurs
Solution Approach 1:
The patent adds a spatial dimension to monitoring by positioning multiple optical encoders at different locations along the print media path. This dimensional expansion enables the system to capture stretch information in both in-track and cross-track directions, transforming a single-point measurement into a multi-point spatial measurement system that recovers previously lost information
3Measurement precision
If multiple optical encoders are used to detect print media stretch, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent makes each optical encoder multi-functional by designing them to simultaneously measure multiple parameters including position, velocity, in-track stretch, and cross-track stretch. This universality allows the encoders to perform comprehensive measurement tasks that would otherwise require multiple specialized sensors, thereby improving measurement precision while limiting the increase in device complexity
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 simplifies integration with existing print medium transport, allowing for accurate detection and compensation of print media shifts and distortions, enhancing print quality and registration.
Implementation Method 1
a single 2D optical encoder having a coherent or quasi-coherent light source that reflects light from the print media that is received by a detector for tracking the motion of the print media
Data Source
AI summary
A printing system includes at least one print module for printing on a receiver media; a mechanism for moving the receiver media past the at least one print module; at least a first and second optical encoder sensor for measuring at least one of displacement and velocity of the receiver media which provides an output signal to a controller; wherein the controller, in response to the signals received from the at least two optical encoder sensors, controls the operation of the at least one print module.