Inkjet Printer Web Defect Detection Using Collimated Laser
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Solution Overview
Problem
Inkjet printers face damage and image imperfections due to defects in the continuous web of recording media, such as edge damage, wrinkles, and foreign matter, which can lead to burnishing of printheads and poor image quality, especially when the gap between the printhead and the imaging surface is not properly maintained.
Innovation Solution
An inkjet printer system equipped with a detector and a method using a collimated laser light beam to detect defects in the continuous web of recording media and transport rollers, allowing for real-time adjustment of the printhead operation to prevent damage and maintain optimal imaging conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the gap between the printhead and the imaging surface is reduced to improve imaging precision, then manufacturing precision is improved, but the risk of printhead damage from web defects increases
Solution Approach 1:
The defect detection system performs preliminary detection of web defects (edge damage, wrinkles, foreign matter) before the web reaches the printhead. When a defect is detected, the system proactively adjusts the gap or stops printing in advance, preventing the defect from causing printhead damage while maintaining optimal imaging precision during normal operation
Solution Approach 2:
The system dynamically adjusts the gap between the printhead and imaging surface based on real-time defect detection. The gap can be increased when defects are present and reduced to optimal levels when the web is clear, allowing the system to balance imaging precision with printhead protection continuously during operation
2Reliability
If the gap between the printhead and the imaging surface is increased to prevent printhead damage, then reliability is improved, but manufacturing precision deteriorates
Solution Approach 1:
The defect detection system performs preliminary detection of web defects before they reach the printhead. When defects are detected, the gap is increased in advance to protect the printhead. When no defects are present, the gap returns to the optimal smaller setting for high imaging precision, thus maintaining both reliability and manufacturing precision
Solution Approach 2:
The system dynamically adjusts the gap based on real-time web condition monitoring. The gap is increased only when and where defects are detected, and maintained at optimal levels otherwise, allowing the system to achieve both printhead protection and high imaging precision through adaptive control
3Reliability
If real-time defect detection and adjustment systems are added to prevent printhead damage, then reliability is improved, but device complexity increases
Solution Approach 1:
The defect detection system acts as an intermediary between the web transport and printhead. It monitors web conditions and communicates defect information to the control system, which then adjusts the gap or printing parameters. This intermediary approach enables reliable printhead protection through a modular addition rather than fundamentally redesigning the entire printing system
Solution Approach 2:
The system implements feedback control by continuously monitoring web defects and automatically adjusting printing parameters or gap settings in response. This feedback mechanism enables the system to maintain reliability through automatic defect response, reducing the need for complex manual intervention or oversimplified designs
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
The system effectively reduces printhead damage and improves image quality by detecting and responding to defects in the recording media and rollers, ensuring accurate ink placement and extending printer lifespan by preventing burnishing and maintaining optimal imaging conditions.
Implementation Method 1
A transmitter is disposed at the first end of the roller to transmit a beam of laser light across the roller
Implementation Method 2
A receiver is disposed at the second end of the roller to receive the transmitted beam of laser light and to generate a first signal in response to a portion of the continuous web of recording media positioned between the transmitter and the receiver and the roller diverting the laser light from the first path
Data Source
AI summary
An inkjet printer for printing on a continuous web of recording media includes a receiver to receive a beam of collimated light transmitted across the surface of a continuous web of recording media supported by a roller. The intensity of the transmitted beam received by the receiver can be used to determine the presence of a defect in the continuous web or in the roller. A controller is configured to reduce the speed of or stop movement of the web through the printer and to retract one or more printheads from a printing location to prevent the defect from damaging the printhead(s).