Colour Proofing Apparatus with Optical Sensor
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Solution Overview
Problem
Current colour proofing methods in the printing industry lack accuracy in predicting the colour of printed products, particularly in flexographic printing, due to variations in pressure and ink drying time, which are difficult to replicate in hand-held or miniature proofing devices.
Innovation Solution
A colour proofing apparatus with an engraved roller, back pressure cylinder, and optical sensor that simulates the flexographic print process by applying ink to a substrate, measuring colour values under controlled conditions, and using empirical data or mathematical models to predict actual print product colours, thereby reducing variables that affect colour reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hand-held proofing apparatus is used to apply ink film onto substrate sample, then colour inspection can be performed, but measurement precision is poor due to variable pressure application and lack of controlled conditions
Solution Approach 1:
The patent creates a simplified copy of the essential flexographic printing mechanism using a proofing apparatus with an engraved roller and back pressure cylinder. This miniature model reproduces the critical ink transfer process without requiring a full printing press, enabling controlled colour measurement while maintaining relevance to the actual printing process.
Solution Approach 2:
The patent controls and standardizes key parameters including pressure application through the back pressure cylinder, ink film thickness via the engraved roller cavities, and measurement conditions through integrated optical sensors. By fixing these parameters, the system achieves reproducible colour measurements that accurately predict actual print results.
2Measurement precision
If miniature version of printing press is used to simulate flexographic print process, then colour prediction accuracy improves, but device complexity increases
Solution Approach 1:
The patent extracts only the essential elements needed for colour measurement from the complete flexographic printing process: the engraved roller with ink cavities, the back pressure cylinder for controlled pressure, and the substrate. By removing non-essential components like the full printing press mechanism, the system achieves accurate colour prediction with reduced complexity.
Solution Approach 2:
The proofing apparatus is designed to serve multiple functions: applying ink through the engraved roller, controlling pressure via the back pressure cylinder, conveying the substrate, and measuring colour through integrated optical sensors. This multi-functionality reduces the need for separate devices and simplifies the overall system.
3Reliability
If flexographic print process is simulated with variable pressure conditions, then colour measurement can be performed, but reproducibility deteriorates due to pressure variations and ink drying time effects
Solution Approach 1:
The back pressure cylinder is pre-configured to apply consistent pressure to the engraved roller during the proofing process. This preliminary setup ensures that pressure variations are eliminated before the ink application and measurement occur, creating reproducible conditions that accurately reflect actual printing processes.
Solution Approach 2:
The patent replaces complex mechanical pressure control systems with a simplified back pressure cylinder mechanism that provides stable, controlled pressure. This substitution eliminates the need for complex pressure regulation while maintaining consistent conditions throughout the proofing process, improving both reproducibility and ease of operation.
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 significantly improves colour prediction accuracy by controlling pressure and ink application, eliminating the effect of ink drying time and simplifying the measurement process, allowing for the selection of optimal engraved roller screens and interpolation of untested colour values.
Implementation Method 1
an optical sensor disposed at the conveyor for measuring a colour value of the sheet that has passed through the nip
Data Source
AI summary
A color proofing apparatus, including an engraved roller (12) having a pattern of ink accommodating cavities on its peripheral surface, a back pressure cylinder (14) forming a nip with the engraved roller (12), a conveyor (16) adapted to feed a sheet (18) of a print substrate through the nip in synchronism with the movements of the peripheral surfaces of the engraved roller (12) and the back pressure cylinder (14), and an optical sensor (30) disposed at the conveyor (16) for measuring a color value of the sheet (18) that has passed through the nip.