Printer Calibration Transfer Functions for Optical Density Drift
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Solution Overview
Problem
High-speed production printers experience changes in optical density over time due to printhead wear, leading to inconsistent color management, and existing recalibration methods waste paper and time.
Innovation Solution
A printer calibration mechanism that uses a compensation module to generate transfer functions for maintaining optical density consistency by recalibrating the printer using a compensation process, which includes a measurement module to gather data and a calibration engine to update transfer functions based on substrate and printer characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If recalibration is performed using a standard reference paper, then optical density consistency is restored, but paper and ink are wasted and time is lost
Solution Approach 1:
The patent creates a virtual copy or model of the substrate's optical properties through the substrate model, which represents the substrate's transfer function. This model allows the system to simulate and predict printing outcomes without physically printing test patterns on actual substrate, thereby eliminating paper and ink waste while maintaining calibration accuracy.
Solution Approach 2:
The patent replaces the physical mechanical process of printing test patterns and measuring them with a computational model-based system. The substrate model computationally predicts the substrate's effect on ink deposition, eliminating the need for physical trial printing and measurement iterations.
2Reliability
If recalibration is performed using a standard reference paper, then optical density consistency is restored, but additional time is required to change paper and perform recalibration
Solution Approach 1:
The system performs preliminary characterization of the substrate to create a substrate model in advance. This model is then reused for multiple printing operations and calibration adjustments, eliminating the need to perform time-consuming physical recalibration procedures each time optical density drift occurs.
Solution Approach 2:
By creating a virtual substrate model that captures the substrate's transfer function, the system can perform computational recalibration instantly without physical paper changes or time-consuming measurement cycles.
3Measurement precision
If the substrate model is updated frequently to adapt to substrate changes, then color management precision is maintained, but processing time increases
Solution Approach 1:
The system updates the substrate model selectively rather than continuously - only when actual substrate changes are detected or when calibration drift exceeds thresholds. This partial updating approach maintains color management precision while minimizing unnecessary processing time consumption.
Data Source
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AI summary
A printing system (130) includes at least one physical memory device (1425) to store calibration logic and one or more processors (1410) coupled with the at least one physical memory device to execute the calibration logic to receive a reference halftone design, receive reference ink drop size data, receive a reference printer transfer function corresponding to the reference halftone design, a reference printer response target and a reference print substrate, receive first print measurement data corresponding to the reference halftone design, the reference printer transfer function and a first print substrate, receive first printer response target, generate a first intermediate print substrate transfer function based on the first print measurement data and the first printer response target, generate a first printer transfer function based on the first intermediate print substrate transfer function, the reference halftone design, the reference ink drop size data and the reference printer transfer function and generate a first print substrate transfer function as an approximation of a function with input values determined as the first printer transfer function evaluated at digital count values and output values determined as the composition of the first intermediate print substrate transfer function and the reference printer transfer function evaluated at the digital count values, wherein a transfer function comprises a mapping of an input digital count to an output digital count.