Substrate Chilling Before Ink Application to Prevent Dot Shrinkage
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Solution Overview
Problem
Existing ink printing systems face challenges in preserving image quality due to temperature discrepancies between the marking material and the substrate, leading to dot spreading and shrinkage, especially in duplex printing and on coated papers.
Innovation Solution
A printing system and method that involves chilling the substrate prior to applying marking material using a chilling device equipped with vortex nozzles or a chill-spray device, ensuring the substrate is cooled to an optimal temperature range to prevent dot shrinkage and improve ink spread.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If marking material is applied to a substrate at ambient temperature, then the marking material can be applied efficiently, but the individual dots spread out and shrink back, decreasing image quality
Solution Approach 1:
The substrate is cooled below ambient temperature before the marking material is applied to it. This preliminary cooling action prevents the thermal expansion and subsequent shrinkage of the marking material dots, thereby maintaining image quality without compromising application efficiency
2Manufacturing precision
If the substrate is cooled below ambient temperature before marking material application, then image quality is improved by preventing dot shrinkage, but additional cooling equipment and process steps are required
Solution Approach 1:
A chilling device is introduced as an intermediary component between the substrate transport system and the marking material device. This chilling device temporarily cools the substrate below ambient temperature only in the specific region where marking material will be applied, rather than cooling the entire substrate or requiring complex system-wide temperature control
3Productivity
If a dryer is used to dry marking material on the first side of a substrate in a duplex printing system, then the marking material is dried effectively, but the substrate temperature increases and causes dot shrinkage on the second side when marking material is applied
Solution Approach 1:
Before the substrate enters the marking material device on the second side, it is cooled below ambient temperature to counteract the heating effect from the dryer. This preliminary cooling action prevents the thermal shrinkage of marking material dots that would otherwise occur due to the elevated substrate temperature
4Ease of manufacture
If marking material is applied to coated paper, then the coating prevents ink absorption into paper fibers, but the liquid marking material moves excessively before drying, increasing overlay graininess
Solution Approach 1:
The temperature parameter of the substrate is changed by cooling it below ambient temperature before marking material application. This temperature change increases the viscosity of the liquid marking material, reducing its mobility and preventing excessive movement before drying, thereby reducing overlay graininess on coated paper
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 cooling of the substrate before ink application enhances image quality by maintaining ink spread and preventing excessive movement of liquid ink, thereby reducing overlay graininess and improving the final image quality on both single and duplex printed substrates.
Implementation Method 1
a chilling device arranged to chill substrates moving proximate thereto
Implementation Method 2
A printing system and method that involves chilling the substrate prior to applying marking material using a chilling device equipped with vortex nozzles
Implementation Method 3
the cooled substrate increases the viscosity of marking material applied thereto-preventing the liquid marking material from excessively moving before drying
Data Source
Figure 1A~1D
Figure 2A~2F
Figure 3
AI summary
An apparatus for preserving image quality printed on a substrate comprising a chilling device arranged to chill substrates moving proximate thereto, at least one marking material device, the marking material device arranged to form images on the substrates, and a media transport system configured to move the substrates past the chilling device and further configured to move the substrates past the at least one marking material device to form images on the substrates.