Print Medium Deformation Detection via Chart Density Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current printing apparatuses struggle to accurately detect deformation of web paper during transportation, which affects shading correction and results in improper printing due to the deformation occurring before the paper is wound, making existing optical detection methods ineffective.
Innovation Solution
A printing apparatus that uses image processing on a correcting chart to calculate moving average values and standard deviations of density information from multiple recording elements to determine deformation, allowing for accurate detection and correction of paper deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical detection is performed on wound web paper, then deformation can be detected in a controlled state, but the device cannot detect deformation that occurs during transportation
Solution Approach 1:
The invention performs deformation detection on the correcting chart before the actual printing process by detecting density variations that indicate paper deformation. This preliminary detection allows the system to identify deformation issues before they affect the main printing operation, enabling proactive correction or adjustment of printing parameters.
Solution Approach 2:
The correcting chart serves as an intermediary object that carries deformation information from the web paper to the detection system. By printing the correcting chart on the web paper and then detecting its density variations, the system indirectly measures paper deformation without requiring direct mechanical measurement of the paper itself during transportation.
2Productivity
If shading correction is performed based on density values from deformed web paper, then correction can be completed, but the correction becomes improper due to deformation-induced density variations
Solution Approach 1:
The system performs preliminary deformation detection by analyzing density variations in the correcting chart before executing shading correction. This allows the system to identify when paper deformation is present and adjust the correction process accordingly, preventing improper correction based on distorted density measurements.
Solution Approach 2:
The invention uses density information from the correcting chart as feedback to determine whether paper deformation has occurred. This feedback mechanism allows the system to adapt the shading correction process based on the actual state of the web paper, ensuring accurate correction only when deformation is absent or minimal.
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
Enables precise detection and correction of paper deformation, ensuring consistent printing quality by adjusting shading correction based on deformation data, thereby improving the accuracy of density uniformity across the print medium.
Implementation Method 1
the printed correcting chart is optically read for determining densities of portions of the web paper corresponding to the nozzles individually
Data Source
AI summary
Provided is a printing apparatus having a printing unit with recording elements arranged in a width direction of a print medium. The printing apparatus includes a printer printing a correcting chart to the print medium, a correcting-chart density information obtaining device obtaining density information on the correcting chart printed to the print medium, and a print-medium deformation determining device setting at least two different numbers of the recording elements as moving average widths from the density information on the correcting chart, calculating moving average values of the density information of the recording elements for the moving average widths, calculating a standard deviation using the moving average values for the small and large moving average widths, respectively, and determining that deformation occurs in the print medium when the standard deviation used as a determination value exceeds a threshold.