Inkjet Printer Auxiliary Dryer Controls Ink Spread on Coated Media
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Solution Overview
Problem
Inkjet printers face issues with ink drop spread on coated media, leading to image quality defects such as coalescence, puddling, and intercolor bleed due to uneven drying and absorption, particularly on glossy and matte surfaces.
Innovation Solution
The system employs a plurality of printheads with auxiliary dryers positioned adjacent to control ink drop spread, along with a main dryer of higher power rating to ensure efficient drying, and a controller to coordinate the operation of printheads, auxiliary dryers, and media transport to manage ink drop spread and drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If aqueous ink is used on glossy or semi-glossy coated media, then color richness is improved, but ink drop spread increases causing coalescence and puddling
Solution Approach 1:
The patent applies preliminary action by heating the media surface before ink ejection to reduce surface tension and prevent excessive ink spread. The media is pre-heated to a temperature sufficient to control ink drop coalescence and puddling, thereby maintaining ink drop position uniformity while preserving color richness on glossy coated media.
2Productivity
If aqueous ink is used on matte coated media, then absorption is improved, but ink drop spread increases causing loss of color richness
Solution Approach 1:
The patent applies preliminary action by pre-heating the matte media surface before ink ejection to control the absorption rate and prevent excessive ink penetration. This maintains color richness while ensuring adequate drying speed by optimizing the initial surface temperature to regulate ink uptake.
3Area of stationary object
If ink drops are allowed to spread before drying, then coverage is improved, but intercolor bleed increases
Solution Approach 1:
The patent applies preliminary action by pre-heating the media surface to control ink spread characteristics. This allows sufficient coverage area while preventing intercolor bleed by maintaining optimal surface temperature that limits lateral ink migration before the ink dries and color boundaries are established.
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 configuration reduces ink drop spread, minimizing coalescence and puddling, and ensures uniform ink thickness and color richness, while preventing intercolor bleed by controlling the temperature and dryness of the ink drops effectively.
Implementation Method 1
a first dryer positioned downstream of the printhead to heat a surface of the media
Implementation Method 2
a second dryer positioned downstream of the first dryer to dry the ink image
Implementation Method 3
The ink surface tension may be reduced by heating the media surface prior to the ink contacting the media surface
Data Source
AI summary
A printer comprises a plurality of printheads, at least one auxiliary dryer positioned immediately adjacent the plurality of printheads and configured to control spread of ink drops ejected by the plurality of printheads, a main dryer positioned to dry ink on the media after the media has passed the at least one auxiliary dryer, at least one actuator to drive media transport and move media past each of these components, and a controller. The power of the main dryer is higher than the power of the auxiliary dryer. The controller is operatively connected to each of the components and is configured to control the operation of the at least one auxiliary dryer with reference to the type of media being printed and the type of ink being ejected. A method for operating the printer is also disclosed.