Cool Gas Jet Flow Generator for Printing Dryer Web Scorching
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Solution Overview
Problem
High-speed continuous-form printers face issues with scorching or burning of printed webs due to uneven heat distribution in radiant dryers, leading to increased fire risk and permanent warping or distortion.
Innovation Solution
A flow generator is integrated into the dryer to project a jet of cool gas directly onto the web, disrupting the heated air and reducing temperature differences between marked and unmarked portions, thereby preventing scorching or burning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If radiant heat lamps are used to dry ink on the web, then drying efficiency is improved, but marked portions of the web scorch or burn due to uneven heat distribution
Solution Approach 1:
The patent introduces a flow generator that projects a jet of cool gas at specific locations (marked portions) of the web that are experiencing excessive heat absorption. This localized cooling approach addresses the uneven heat distribution problem by applying cooling only where needed, rather than uniformly across the entire web, thus maintaining drying efficiency while preventing scorching of dark ink areas.
2Speed
If radiant heat lamps are used to dry ink on the web, then drying speed is improved, but permanent warping and distortion of the web occurs
Solution Approach 1:
The flow generator applies cool gas jets locally to marked portions of the web that are absorbing excessive radiant energy. This localized intervention prevents differential thermal expansion and contraction between marked and unmarked areas, thereby preventing warping and distortion while maintaining the overall high drying speed provided by the radiant heat lamps.
3Productivity
If the web moves quickly through the dryer, then productivity is improved, but the web still has a chance of scorching or burning
Solution Approach 1:
The cool gas acts as an intermediary substance between the radiant heat lamps and the web. By introducing this intermediate cooling medium at critical locations, the system can maintain high throughput speeds while the cool gas absorbs excess heat from marked portions, preventing ignition and reducing fire risk even during rapid web passage.
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 solution effectively reduces the risk of ignition and warping by evening out temperature differences across the web, ensuring consistent drying and minimizing distortion.
Implementation Method 1
The flow generator projects a jet of impinging gas directly onto the web, which disrupts air within the dryer that is proximate to the web. The impinging gas is cool with respect to the air within the dryer and therefore, the projected gas cools the heated web.
Implementation Method 2
A flow generator is integrated into the dryer to project a jet of cool gas directly onto the web, disrupting the heated air and reducing temperature differences between marked and unmarked portions
Implementation Method 3
A typical radiant dryer includes an array of lamps that emit light and heat. The light and heat from the lamps helps to dry the ink as the web passes through the dryer.
Implementation Method 4
marked portions of the web, which are darker, will absorb more radiant infrared energy from the dryer than un-marked, blank portions of the web
Data Source
AI summary
Systems and methods are provided for inserting low temperature gas into dryers of printing systems. The system comprises a dryer, which includes a heating element and a flow generator. The heating element is within an interior of the dryer and is able to heat a web of printed media as the web travels through the interior. The flow generator is within the interior and is operable to directly project an impinging jet of gas along a width of the web that deflects heated air proximate to the web. The gas is cooler than the heated air.