Gamma Correction Table Update for Non-Reference Paper Types
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Solution Overview
Problem
Existing image processing apparatuses struggle to accurately calibrate output images when using paper types with different characteristics, as they are often classified as the same plain paper, leading to inaccurate gamma correction tables and inconsistent print densities.
Innovation Solution
The apparatus includes an obtaining unit for gamma correction tables, a first reading unit for plain paper, a second reading unit for an image bearing member, a comparison unit to assess value differences, and a correction unit to adjust the correlation for non-reference paper, ensuring accurate gamma correction even when using plain paper with different characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If paper types with different characteristics are classified as the same plain paper for user convenience, then ease of operation is improved, but manufacturing precision deteriorates due to inaccurate gamma correction tables
Solution Approach 1:
The patent segments the plain paper category into multiple sub-categories based on grammage ranges (e.g., 65-80 g/m2, 81-90 g/m2, 91-110 g/m2). Each sub-category has its own reference paper characteristics and correlation data, allowing precise matching while maintaining user-friendly classification. This segmentation resolves the contradiction by enabling both ease of operation through classification and manufacturing precision through accurate matching.
Solution Approach 2:
The patent changes the parameter of paper characteristic matching from binary (same/different type) to continuous (grammage-based correlation). By storing correlation data between reference paper and non-reference paper across different grammage ranges, the system dynamically adjusts the matching precision based on the actual paper characteristics, thereby maintaining both ease of operation and manufacturing precision.
2Measurement precision
If calibration is executed using reference paper with well-defined characteristics, then measurement precision is improved, but adaptability deteriorates because the system cannot handle other paper types within the same classification
Solution Approach 1:
The patent makes the reference paper system universal by establishing correlation relationships between a single reference paper type and multiple non-reference paper types within the same classification. The system can handle various paper types (different grammage, thickness, composition) using one reference paper through stored correlation data, thereby achieving both measurement precision and adaptability.
Solution Approach 2:
The patent introduces correlation data as an intermediary between reference paper characteristics and non-reference paper characteristics. This intermediary layer enables the system to translate calibration results from reference paper to various other paper types, maintaining measurement precision while extending adaptability to multiple paper types within the same classification.
3Manufacturing precision
If the system stores detailed characteristic correlations between reference paper and non-reference paper, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by storing detailed correlation data only for specific grammage ranges and paper type combinations that are actually used. Rather than maintaining comprehensive correlations for all possible paper types, the system stores correlation data locally for each relevant paper type pair, achieving manufacturing precision where needed while minimizing device complexity by avoiding unnecessary data storage.
4Manufacturing precision
If the system performs correlation correction based on grammage differences, then manufacturing precision is improved, but loss of time increases due to additional calculation steps
Solution Approach 1:
The patent performs preliminary action by pre-calculating and storing correlation data between reference paper and non-reference paper for various grammage ranges during system initialization or calibration phases. This pre-computed correlation data is then quickly retrieved and applied during actual printing operations, achieving manufacturing precision through correlation correction while minimizing loss of time by avoiding real-time complex calculations.
Data Source
AI summary
An image processing apparatus includes an obtaining unit configured to obtain a gamma correction table used for image formation on non-reference paper using a correlation between a characteristic of reference paper and a characteristic of the non-reference paper and a gamma correction table obtained through calibration using the reference paper, a first reading unit configured to form a pattern on plain paper and read the formed pattern, a second reading unit configured to form a pattern on an image bearing member and read the formed pattern, a comparison unit configured to compare a value read by the first reading unit with a value ready by the second reading unit, and a correction unit configured to correct the characteristic indicating the correlation used for obtaining the gamma correction table for the non-reference paper by the obtaining unit when a difference of values compared by the comparison unit exceeds a first threshold.