Ink Control Method for Printing Press Using Optical Density Feedback
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Solution Overview
Problem
The existing color control methods in printing presses do not effectively account for the dependence of the optical effect of printing ink on the layer thickness of a top color applied to the printing material, leading to inconsistencies in color output during the printing process.
Innovation Solution
The method involves applying an opaque cover ink followed by a translucent printing ink, with inline and online measurement and control of optical densities using densitometers to maintain target values, ensuring that the optical density of the printing ink is 75% of the top color's optical density, thereby accounting for the layer thickness dependence in color control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing color control methods are used, then the printing process can proceed with standard control procedures, but the optical effect of printing ink does not accurately reflect the actual layer thickness of the top color
Solution Approach 1:
The patent implements a feedback mechanism where the optical density of the top color is measured inline, and this measurement is used to dynamically adjust the dosing of the printing ink in subsequent printing units. The control device receives the actual optical density value and uses it to calculate and apply corrective dosing adjustments, ensuring that color output remains consistent despite variations in top color layer thickness.
Solution Approach 2:
The system performs preliminary measurement of the top color's optical density before the printing ink is applied. By measuring the actual layer thickness of the top color in advance and using this information to pre-calculate the required dosing adjustments, the system ensures accurate color control is achieved before the printing ink application occurs.
2Adaptability or versatility
If the optical density of the top color varies due to layer thickness fluctuations, then measurement readings change, but standard control methods do not compensate for this variation
Solution Approach 1:
The control device continuously receives feedback from inline optical density measurements of the top color and dynamically adjusts the printing ink dosing accordingly. This closed-loop feedback system enables the control system to adapt to real-time variations in top color layer thickness, maintaining accurate color density control throughout the printing process.
Solution Approach 2:
The patent transforms the static, predetermined dosing approach into a dynamic control system that continuously adapts to changing conditions. The dosing of the printing ink is no longer fixed but is dynamically adjusted based on real-time measurements of the top color's optical density, allowing the system to respond flexibly to layer thickness variations.
3Measurement precision
If inline measurement devices are implemented, then real-time optical density data can be obtained, but the complexity of the control system increases
Solution Approach 1:
The control device serves multiple functions: it receives and processes optical density measurements from the inline measurement device, calculates the appropriate dosing adjustments based on these measurements, and controls the dosing mechanisms of the printing units. By consolidating these functions into a single multi-functional control device, the system achieves real-time measurement and control without proportionally increasing overall system complexity.
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 ensures consistent color output by maintaining the optical density of the printing ink relative to the top color, despite fluctuations in ink layer thickness, thereby improving color control in printing presses.
Implementation Method 1
at least one actual value for the optical density of this covering ink 02 is determined, preferably inline, i.e. in the relevant printing press, by a first detection device
Data Source
Figure 1~2
AI summary
The invention relates to a method for ink control in a printing press, wherein: in a printing process in progress, an opaque cover ink (02) is printed onto a printing substrate (01) in a first printing unit (06) and subsequently a transparent printing ink (03) is printed onto the cover ink (02) in a second printing unit (07); for the cover ink (02) printed onto the printing substrate (01), at least one actual value of the optical density of said cover ink (02) is determined by a first sensing device (08); for said cover ink (02), a layer thickness thereof to be applied to the printing substrate (01) is set at the printing unit (06) in question by a control unit (11), which acquires the at least one actual value of the optical density of said cover ink (02), in accordance with a previously determined value of the optical density of the surface of the unprinted printing substrate (01) in such a way that the at least one actual value of the optical density of said cover ink (2) sensed by the first sensing device (08) corresponds, in view of a tolerance range defined for said cover ink (02) in the control unit (11), to a target value set for said cover ink (02) at said control unit (11); for the printing ink (03) printed onto the previously printed cover ink (02), at least one actual value of the optical density of said printing ink (03) is determined by a second sensing device (09); for said printing ink (03), a layer thickness thereof to be applied to the cover ink (02) is set at the printing unit (07) which prints said printing ink (03) by the control unit (11), which also acquires the at least one actual value of the optical density of said printing ink (03), in accordance with the layer thickness of the cover ink (02) previously applied to the printing substrate (01) or in accordance with the actual value of the optical density of said cover ink (02) in such a way that the at least one actual value of the optical density of said printing ink (03) sensed by the second sensing device (09) corresponds, in view of a tolerance range defined for said printing ink (03) in the control unit (11), to a target value set for said printing ink (03) at the control unit (11).