Inkjet Substrate Web Pause Speed Control for Register Stability
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Solution Overview
Problem
Inkjet printing systems face print image disruptions and defects due to substrate web swelling or shrinking during pauses, caused by environmental temperature and moisture differences, leading to register errors and distortions upon resumption of printing.
Innovation Solution
Implementing a pause function in inkjet printing systems that reduces the feed speed of the printing substrate web to a predetermined speed for a selected duration to allow adaptation to environmental conditions, ensuring suitable properties under the printing unit upon resumption, with options for 'downtime pause with lead time' and 'creep pause' to minimize disruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the printing substrate web is stopped completely during pause function, then print image disruptions occur due to substrate swelling or shrinking from environmental exposure, but continuous printing maintains productivity without pause
Solution Approach 1:
The patent applies preliminary action by reducing the feed speed to a predetermined low speed for a predetermined time period before the actual pause. This lead time allows the printing substrate web to adapt to environmental conditions (temperature and humidity) gradually, preventing sudden swelling or shrinking that would cause print image disruptions when printing resumes
Solution Approach 2:
The patent implements dynamics by using a variable feed speed profile instead of a simple stop-start mechanism. The feed speed is dynamically adjusted: reduced to a predetermined low speed during lead time, maintained during pause, then accelerated back to printing speed. This dynamic control minimizes thermal and moisture shock to the substrate
2Measurement precision
If the feed speed is reduced to zero during pause, then substrate web position stability improves for monitoring and correction, but print image disruptions occur upon resumption due to environmental exposure
Solution Approach 1:
The patent performs preliminary adaptation by maintaining the substrate web in motion at a predetermined low speed during the lead time before pause. This gradual speed reduction allows the substrate to acclimate to environmental conditions progressively, preventing the sudden dimensional changes that would cause print image disruptions upon resumption
Solution Approach 2:
The patent applies preliminary anti-action by counteracting the harmful effects of complete stopping through the lead time phase. During this phase, the substrate web is exposed to environmental conditions in a controlled, gradual manner that prevents the swelling or shrinking that would otherwise occur with abrupt stopping and resumption
3Manufacturing precision
If the pause duration is extended to allow substrate adaptation to environmental conditions, then print image quality improves, but productivity and printing efficiency decrease
Solution Approach 1:
The patent applies parameter changes by optimizing the predetermined time period and predetermined speed values based on the specific printing substrate material and environmental conditions. These parameters are adjusted to achieve the minimum necessary pause duration for substrate adaptation, balancing print image quality with printing efficiency
Solution Approach 2:
The patent uses dynamic speed control to minimize pause impact on productivity. By reducing speed to a predetermined low speed rather than complete stop, and by optimizing the duration of this reduced-speed phase, the system achieves substrate adaptation with minimal interruption to the overall printing process
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 approach reduces print image disruptions by ensuring the substrate web is in a stable state regarding moisture and temperature, improving print quality by minimizing position fluctuations and compensating for environmental influences during pauses.
Implementation Method 1
the printing substrate web 3 is exposed to environmental air, with the consequence that here a swelling of the print substrate web 3 can occur due to the humidity of the environmental air
Implementation Method 2
Temperature and moisture difference between the print substrate web 3 and the environmental air, with the swelling or shrinking of said print substrate web 3 that are thereby incurred with this
Data Source
AI summary
In a method to execute a pause function in an inkjet printing system with at least one printing apparatus, the pause function is triggered to reduce a feed speed of the printing substrate web from a speed during printing operation to a predetermined speed for a predetermined duration. The duration is selected so that the printing substrate has suitable properties with regard to at least one of the elements selected from the group consisting of moisture and temperature under the printing unit of the printing apparatus at an end of the pause function. After ending the pause function, the printing substrate web is accelerated again to the speed during the printing operation.