Substrate Pre-Chilling for Ink Spread Control in Duplex Printing
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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 cooling or chilling the substrate prior to applying marking material, using a chilling device with vortex nozzles and air knives to create a cold air stream that chills the substrate to an optimal temperature range, thereby improving ink spread and preventing excessive movement of liquid ink.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If marking material is applied to a substrate at ambient temperature, then the marking material can be applied easily, 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 marking material from spreading out and shrinking back after application, thereby maintaining image quality while preserving ease of application
2Manufacturing precision
If the substrate is cooled below ambient temperature before marking material application, then image quality is improved, but additional cooling equipment and process steps are required
Solution Approach 1:
A layer of ice is formed on the substrate as an intermediary medium. This ice layer acts as a thermal mediator that absorbs excess heat from the marking material upon application, preventing dot spread and shrinkage without requiring complex active cooling systems
Solution Approach 2:
The invention utilizes the phase transition of water to ice on the substrate surface. This phase change creates a cold surface that thermally manages the marking material application process, improving image quality through a natural physical process rather than mechanical cooling
3Productivity
If a dryer is used to dry marking material on the first side of a substrate, then the marking material dries effectively, but the substrate temperature increases, causing undesirable characteristics when marking material is applied to the opposite side
Solution Approach 1:
The substrate is cooled below ambient temperature before marking material is applied to the opposite side. This preliminary cooling counteracts the heat from the dryer, preventing excessive spreading and shrinkage of the marking material on the second side while maintaining efficient drying on the first side
4Duration of action of moving object
If marking material is applied to coated paper, then the marking material remains in liquid form longer, but it moves excessively before drying, increasing overlay graininess
Solution Approach 1:
The temperature of the substrate is changed by forming an ice layer on it. This temperature parameter change increases the viscosity of the marking material upon contact, reducing its流动性 and preventing excessive movement before drying, thereby reducing overlay graininess while maintaining appropriate liquid retention time
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 chilling of the substrate before ink application enhances image quality by maintaining ink spread, reducing overlay graininess, and ensuring uniformity of ink drops, even in duplex printing and on coated papers.
Implementation Method 1
A printing system and method that involves cooling or chilling the substrate prior to applying marking material, using a chilling device with vortex nozzles and air knives to create a cold air stream that chills the substrate
Implementation Method 2
using a chilling device with vortex nozzles and air knives to create a cold air stream
Data Source
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.