Heat-Pipe Cooling Drum for Faster Sheet Heat Removal
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Solution Overview
Problem
Existing cooling devices in printing systems, particularly for heavyweight sheets, are limited by the rate of heat conduction from the base to the tip of cooling fins, necessitating slower printer speeds to prevent overheating of printheads.
Innovation Solution
Incorporation of heat pipes within a cooling drum to enhance heat dissipation, utilizing a cylindrical wicking material and a vaporizable liquid to rapidly transfer heat away from printed sheets through convection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling fins are used to increase surface area for heat convection, then heat dissipation capability is improved, but the rate of heat conduction from base to tip of fins limits cooling efficiency
Solution Approach 1:
The patent applies phase transition by using heat pipes that utilize phase change of working fluid (evaporation at hot end, condensation at cold end) to rapidly transport heat from the sheet contact surface to the cooling air, overcoming the conduction limitation of traditional fins and enabling faster printer speeds while maintaining effective cooling
Solution Approach 2:
The patent employs heat pipes that function as thermal transport devices utilizing vapor-liquid phase change and fluid flow principles, where vaporizable liquid circulates within sealed heat pipe structures to efficiently carry heat away from the sheet, replacing the passive conduction mechanism of solid fins
2Productivity
If conventional cooling fins are used, then device structure is simple, but heat removal rate is insufficient for heavyweight sheets
Solution Approach 1:
The patent utilizes phase transition of working fluid within heat pipes (evaporation at the sheet-contact end, condensation at the cooling air end) to achieve rapid heat transport, dramatically improving heat removal rate for heavyweight sheets while containing the complex mechanism within sealed heat pipe structures that present a simple external form
Solution Approach 2:
The patent introduces heat pipes as intermediary thermal transport devices between the sheet contact surface and the cooling air, where the heat pipe acts as a mediator that efficiently transfers heat via phase change, overcoming the limitation of direct conduction through solid fins
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
Facilitates faster printer speeds and improved image quality by effectively cooling sheets to a safe temperature for printhead operation, enabling efficient heat removal even with heavyweight papers.
Implementation Method 1
A plurality of heat pipes extend into an interior of the drum from the inner surface of the cylinder wall
Implementation Method 2
utilizing a cylindrical wicking material and a vaporizable liquid to rapidly transfer heat away from printed sheets
Implementation Method 3
exhausted from an outlet. Cooling fins are sometimes used to increase the surface area and increase the convection rate
Data Source
AI summary
A cooling device suited to cooling sheets includes at least one drum which is mounted for rotation about a central axis. The drum includes a cylindrical wall which defines an outer surface and an inner surface. A plurality of heat pipes extend into an interior of the drum from the inner surface of the cylinder wall. The cooling device may be incorporated into a printing device and configured for cooling printed sheets prior to the sheets entering an inkjet marking device.