Radiant Heating Panel Positioning for Web Temperature Control
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Solution Overview
Problem
Existing media heaters in imaging devices face challenges in achieving uniform temperature adjustments for a moving web, leading to non-uniform heating due to the thermal mass of radiant heaters, which can result in poor ink adhesion, embossed images, or 'show through' defects.
Innovation Solution
A radiant heating unit with adjustable panel positions and a web heating controller that varies thermal output and view factor to rapidly adjust heating based on detected web temperature, allowing for faster temperature changes without altering the heater setpoint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If radiant heaters are used to heat the media web, then thermal energy is imparted to the web, but temperature changes in the heaters take a relatively long time to take effect due to thermal mass
Solution Approach 1:
The heating system is divided into multiple independent radiant heating panels that can be individually controlled. Each panel can be independently adjusted in terms of thermal output and view factor, allowing selective heating of different web positions without requiring all panels to reach new temperatures simultaneously, thus reducing overall system response time.
Solution Approach 2:
The heating panels are made dynamically adjustable through two control mechanisms: varying the thermal output of each panel and changing the view factor (angular orientation) of panels relative to the web. This dynamic control allows rapid adjustment of heating characteristics without waiting for thermal mass to equilibrate, directly addressing the slow response time issue.
2Productivity
If the media web moves through the printing system at fast speeds, then productivity is improved, but the thermal output of the radiant panels cannot change fast enough to compensate for temperature changes
Solution Approach 1:
Different portions of the media web receive different heating characteristics through individually controllable panels. Each panel can be adjusted to provide optimal local heating based on its position relative to the web, ensuring uniform temperature distribution across the entire web even at high speeds where overall temperature control is challenging.
Solution Approach 2:
The system changes multiple parameters simultaneously to control heating: thermal output of individual panels and view factor (angular orientation). By adjusting both parameters, the system can rapidly modify heating characteristics to match changing web temperatures at high speeds, maintaining temperature uniformity despite increased productivity.
3Measurement precision
If the detected temperature of the moving web changes, then temperature control precision is improved, but the thermal output of the radiant panels may not be able to change fast enough to compensate
Solution Approach 1:
A temperature sensor detects the actual temperature of the moving web and provides feedback to the control system. Based on this feedback, the controller adjusts the thermal output and view factor of individual heating panels in real-time, creating a closed-loop control system that maintains precise temperature uniformity despite variations in web speed or environmental conditions.
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 solution ensures consistent web heating, improving ink adhesion and preventing defects like embossed images or 'show through', by enabling rapid adjustments in thermal radiation delivery to match changing web temperatures.
Implementation Method 1
radiant heaters positioned along the media pathway for imparting a desired amount of thermal energy to the moving web
Implementation Method 2
a reflective member positioned adjacent the heating panels and configured to reflect thermal radiation emitted by the heating panels onto the media web
Data Source
AI summary
A radiant heating unit is selectively operated to move radiant heating panels to regulate heating of a continuous web of media as the web moves along a media pathway in an imaging device. The radiant heating panels in a radiant heating unit may be moved to any one of a plurality of positions between and including a fully open position and a retracted position in the housing. A panel driver is operated to move the radiant heating panels to one of the positions in the plurality of positions in response to a variable view factor signal.