Printing Apparatus Gloss Uniformity via Temperature Control
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Solution Overview
Problem
Aqueous varnish applied in an in-line manner to printed matter often results in a difference in glossiness between the transport direction and a direction perpendicular to it, which is not effectively addressed by existing technologies.
Innovation Solution
A printing apparatus and method that includes an image recording section, a drying section to heat the recording medium, and a varnish application section, where the varnish is applied after heating, with specific temperature and coating formation time conditions to ensure uniform glossiness, adhering to the relationship Tp−(40/6)×tw≤a, where Tp is the surface temperature, tw is the coating formation time, and 'a' is a constant determining the allowable gloss difference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If aqueous varnish is applied in an in-line manner after image printing, then productivity is improved by continuous processing, but glossiness uniformity deteriorates with directional gloss difference
Solution Approach 1:
The patent applies parameter changes by precisely controlling the temperature of the recording surface (Tp) and the coating formation time (tw) of the aqueous varnish. By establishing the relationship Tp−(40/6)×tw≤a, the patent optimizes these parameters to prevent directional gloss differences while maintaining continuous in-line processing, thus resolving the contradiction between productivity and glossiness uniformity.
2Speed
If the recording surface temperature is increased to dry ink faster, then drying speed is improved, but glossiness difference worsens due to premature varnish application
Solution Approach 1:
The patent implements feedback control by monitoring the temperature of the recording surface and adjusting the timing of varnish application accordingly. The condition Tp−(40/6)×tw≤a serves as a feedback criterion that ensures varnish is applied only when the ink has dried to the appropriate extent, preventing glossiness differences while maintaining efficient drying speed.
Solution Approach 2:
The patent applies preliminary action by controlling the ink drying process before varnish application. By ensuring the ink is sufficiently dried through heated treatment before applying the aqueous varnish, the patent prevents defects such as glossiness differences and wrinkling, thus achieving both fast drying and high glossiness uniformity.
3Loss of time
If varnish is applied immediately after printing, then processing time is reduced, but ink drying completeness worsens causing glossiness defects
Solution Approach 1:
The patent applies dynamics by making the varnish application timing adaptive rather than fixed. The condition Tp−(40/6)×tw≤a dynamically adjusts the optimal application moment based on the actual temperature of the recording surface and the coating formation characteristics of the varnish, ensuring ink drying completeness while minimizing processing time loss.
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 the glossiness difference in the in-plane direction of printed matter by adjusting the temperature and coating formation time of the varnish application, ensuring uniform glossiness across the printed surface.
Implementation Method 1
a drying section that heats the recording medium to dry the ink of the recording surface
Implementation Method 2
a drying section that heats the recording medium to dry the ink of the recording surface
Data Source
AI summary
A printing apparatus and a printing method that can reduce a difference in glossiness in an in-plane direction of a printed matter to which aqueous varnish has been applied. The apparatus and method satisfy a relationship of “Tp−(40/6)×tw≤a” when the temperature of a recording surface at the time of application of aqueous varnish containing water is denoted by Tp, coating formation time of the aqueous varnish is denoted by tw, and a constant determined according to an allowable value of a gloss difference, which is a difference between glossiness of the recording surface of a printed matter of which applied aqueous varnish has been dried in a first direction and glossiness of the recording surface in a direction orthogonal to the first direction, is denoted by a. Here, the unit of the temperature Tp is ° C. and the unit of the coating formation time tw is minute.