Tensioned Thin Guides for Print Head Protection
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Solution Overview
Problem
Existing direct-to-paper ink jet printing systems face issues with clogged print heads due to fibers from printable media lodging in ink nozzles, particularly at corners where hold-down systems like vacuum and electrostatic tacking are ineffective, leading to printing errors, ink wastage, and significant downtime, especially in high-speed or large-format printing.
Innovation Solution
The implementation of a printing system with a print head array and a transport surface using tensioned thin guides positioned between the print head array and the transport surface to prevent edges of the printable medium from contacting the print heads, utilizing a combination of vacuum and adjustable guide systems to ensure effective hold-down and alignment, even at corners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum or electrostatic hold-down systems are used, then the printable medium can be held against the transport surface, but the corners of the medium are not effectively held down and may contact the print head
Solution Approach 1:
The hold-down system is segmented into multiple functional zones: a vacuum/plenum system for the bulk of the medium and separate corner guides specifically positioned to address the corner regions. This segmentation allows each zone to be optimized for its specific function, with corner guides providing additional mechanical restraint where the vacuum system is less effective.
Solution Approach 2:
Corner guides are introduced as intermediary elements between the printable medium and the print head array. These guides act as mediators that specifically address the corner contact problem by providing additional mechanical restraint in the corner regions, while allowing the vacuum system to maintain overall hold-down effectiveness.
2Productivity
If the print head array is mounted closer to the transport surface, then productivity increases, but the risk of media contact with print heads increases
Solution Approach 1:
The solution addresses the proximity problem by adding a spatial dimension - corner guides positioned in the gap between the transport surface and print head array. These guides create an additional spatial barrier that prevents media contact even when the print heads are mounted close to the transport surface, thereby enabling higher productivity without compromising media protection.
Solution Approach 2:
Corner guides serve as intermediary protective elements that allow the print head array to be mounted closer to the transport surface. By providing mechanical restraint at the corners, these guides enable the system to operate with reduced gap between media and print heads, thereby increasing productivity while preventing harmful contact.
3Reliability
If corner guides are added to prevent media contact, then print head protection improves, but device complexity increases
Solution Approach 1:
Instead of making the entire hold-down system more complex, corner guides are applied locally only where needed - at the corner regions. This localized approach provides enhanced protection precisely where the vacuum system is least effective, while keeping the rest of the system simple and maintaining overall structural efficiency.
Solution Approach 2:
The hold-down system is segmented into a simple vacuum/plenum system for the bulk area and separate, simple corner guides for the corner regions. This segmentation allows each component to be simple in design while collectively providing comprehensive protection, avoiding the need for a single complex system to address all requirements.
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 effectively prevents print head clogging by maintaining the edges of the printable medium away from the print head array, reducing downtime and improving print quality by allowing closer mounting of print heads and reducing ink drop placement errors, while accommodating various media sizes and formats.
Implementation Method 1
a vacuum is created under the printable medium, thereby holding the printable medium against the transport surface
Implementation Method 2
the plurality of thin guides held in tension and configured to prevent edges of a printable medium from contacting the print head array
Data Source
AI summary
A print system including a print head array configured to print ink onto a printable medium, a transport surface positioned adjacent to the print head array and configured to transport a printable medium past the print head array and a plurality of thin guides positioned between the transport surface and the print head array, the plurality of thin guides held in tension and configured to prevent edges of a printable medium from contacting the print head array as the printable medium passes under the print head array.