Heated Roller Smoothing for Duplex Thermal Print Density
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Solution Overview
Problem
In duplex thermal transfer printing, the aggressively textured drive roller compromises the paper surface, leading to uneven dye transfer and visible density differences between areas that contact and do not contact the roller, which existing compensation algorithms cannot fully correct.
Innovation Solution
A method involving heating the compromised surface of the printing medium using a heated roller to smooth out indentations and depressions caused by the drive roller, either by pressing it against a heated roller or using additional thermal print heads to apply heat and pressure, thereby improving dye reception and print quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an aggressively textured drive roller is used to maintain traction for precise image registration, then print registration precision is improved, but the paper surface becomes compromised with indentations and depressions causing density variations
Solution Approach 1:
A smoothing roller is introduced as an intermediary component between the textured drive roller and the paper surface. This smoothing roller has a softer, more compliant surface that contacts the paper after it has been gripped by the textured drive roller, thereby smoothing out the indentations and depressions without compromising the registration precision achieved by the textured roller.
Solution Approach 2:
The surface characteristics of the roller contacting the paper are changed from aggressive and textured to smooth and compliant. This parameter change in surface texture and material properties allows the roller to smooth the paper surface while maintaining the registration precision established by the textured drive roller.
2Object-affected harmful factors
If a smoothed surface is applied to the drive roller to prevent surface compromise, then paper surface quality is improved, but traction and grip on the paper deteriorate
Solution Approach 1:
The drive system is segmented into two distinct rollers with different surface characteristics: a textured drive roller that provides traction and grip, and a smooth smoothing roller that prevents surface compromise. This segmentation allows each roller to perform its specific function without compromising the other.
Solution Approach 2:
The smoothing roller acts as an intermediary that processes the paper after it has been gripped by the textured drive roller. This sequential arrangement allows the textured roller to provide necessary traction while the smoothing roller subsequently removes surface defects.
3Manufacturing precision
If compensation algorithms are used in printer firmware to correct density variations, then print uniformity is improved, but the limitations of hardware and firmware prevent complete compensation
Solution Approach 1:
Instead of relying solely on firmware compensation algorithms to correct density variations after printing, a smoothing roller is introduced to preliminarily prevent surface compromise before printing occurs. This proactive approach reduces the burden on compensation algorithms and achieves better overall print uniformity.
Solution Approach 2:
The smoothing roller converts the potentially harmful effect of textured roller contact into a beneficial smoothing action. By transforming the surface compromise into a smoothing opportunity, the system eliminates the need for complex compensation algorithms to correct these specific defects.
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 heat treatment significantly reduces the size of indentations and improves the dye receiving layer's surface, resulting in more uniform print density across the medium, minimizing visible differences and enhancing overall print quality.
Implementation Method 1
heating the compromised surface of the printing medium using a heated roller to smooth out indentations and depressions
Implementation Method 2
pressing it against a heated roller
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A printing method comprising a printhead and rollers for printing. A page of a print job is printed which causes depressions in the non-printed side of the print medium. The print medium is heated to reduce the depressions before printing the non-printed side.