Multiple Print Unit Inkjet System for Paper Cockle Control
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Solution Overview
Problem
Conventional inkjet printers face challenges with paper cockle due to uneven moisture expansion from ink and fixers, which can degrade image quality and require more powerful heaters, potentially damaging printheads and nozzles.
Innovation Solution
A printing system with multiple print units and corresponding heater systems that transfer and dry imaging medium in stages across the print media, using redundant printbar assemblies to distribute ink evenly and manage moisture, thereby preventing paper cockle and maintaining printhead integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If more ink is deposited at a faster rate using page wide array printbar assemblies, then productivity is improved, but paper cockle increases due to excessive moisture
Solution Approach 1:
The patent divides the printing system into multiple print units (first print unit, second print unit, etc.), each responsible for depositing a portion of the total ink. This segmentation allows the ink deposition process to be distributed across multiple units, reducing the moisture load on any single unit and preventing paper cockle while maintaining high overall productivity.
2Object-affected harmful factors
If more powerful heaters are used to dry the ink, then paper cockle is reduced, but printhead and nozzle integrity is compromised
Solution Approach 1:
The heating function is segmented into multiple heater systems, with each print unit having its own heater. This distribution allows each heater to operate at moderate power levels rather than requiring a single powerful heater, thereby drying the ink effectively without generating excessive heat that could damage the printheads and nozzles.
3Reliability
If a reciprocating inkjet pen carriage system is used, then printhead integrity is maintained, but printing redundancy is insufficient to improve image quality
Solution Approach 1:
The patent combines multiple print units with multiple printbar assemblies into a single integrated printing system. This merging provides printing redundancy similar to a reciprocating carriage system, where multiple printheads can re-print the same area if needed, thereby improving image quality while maintaining printhead integrity through the distributed architecture.
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 the likelihood of paper cockle and maintains printhead integrity by distributing ink and heat evenly across the print media, improving image quality and extending the life of printheads.
Implementation Method 1
An electric current is applied to a heating element which causes a small volume of ink to be rapidly heated and vaporized. The ink expands when heated which causes it to be ejected through the nozzle.
Implementation Method 2
Drying the ink with a heater after it has been deposited onto the print media removes, or otherwise dissipates, the water from the ink before it soaks into the fibers and expands the print media.
Implementation Method 3
An electric current is applied to a heating element which causes a small volume of ink to be rapidly heated
Data Source
AI summary
A printing system includes multiple print units which each have one or more printbar assemblies to transfer an imaging medium onto a print media. An individual print unit can include a heater system to dry the imaging medium transferred onto the print media by the one or more printbar assemblies of the individual print unit. For a printing system with two print units, a first percentage of the imaging medium is transferred onto the print media, the print media is advanced beyond the one or more printbar assemblies of the first print unit, and a first heater system dries the first percentage of the imaging medium. A second percentage of the imaging medium is then transferred onto the print media, the print media is advanced beyond the one or more printbar assemblies of the second print unit, and a second heater system dries the second percentage of the imaging medium.