Test Chart Pattern Lengths for Calibration Efficiency

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Solution Overview

Problem

Conventional image forming apparatuses require multiple sheets and excessive toner consumption due to fixed test pattern lengths based on the longest accumulation time, leading to inefficiencies in calibration and color stability.

Innovation Solution

The image forming apparatus adjusts test pattern lengths in the conveyance direction according to individual accumulation times, reducing unnecessary regions and optimizing pattern size, thereby reducing the number of sheets and toner used.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If test pattern lengths are fixed based on the longest accumulation time, then all patterns can be measured, but pattern size and material consumption increase

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidtoner consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies dynamics by making test pattern lengths variable rather than fixed. The control unit dynamically adjusts the length of each test pattern in the conveyance direction based on its specific accumulation time requirement, allowing patterns with shorter accumulation times to have shorter lengths and patterns with longer accumulation times to have longer lengths, thereby optimizing material consumption while ensuring measurement accuracy for each pattern

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies local quality by giving each test pattern a customized length according to its specific measurement requirements. Instead of uniformly setting all patterns to the maximum length, each pattern receives the appropriate local optimization of its dimension in the conveyance direction based on its accumulation time, ensuring that each pattern has the quality (length) it specifically needs without excess

Inventive Principle:
Principle #3Local quality

2Reliability

If test pattern lengths are fixed based on the longest accumulation time, then measurement coverage is ensured, but the number of sheets required increases

Engineering Contradiction:
Improvecalibration accuracyVSAvoidnumber of sheets
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent uses dynamics to optimize sheet utilization by dynamically setting pattern lengths according to accumulation times. This allows multiple patterns to be efficiently arranged on fewer sheets since patterns don't require excessive white space or uniform maximum lengths, thereby reducing the total number of sheets needed while maintaining calibration accuracy

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies merging by consolidating multiple test patterns onto fewer sheets through optimized layout. By reducing individual pattern lengths to match actual needs rather than using maximum length for all, more patterns can be combined on the same sheet, decreasing the total sheet count required for complete calibration

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If uniform test pattern lengths are used, then manufacturing is simple, but patterns with short accumulation times consume excessive toner

Engineering Contradiction:
Improvepattern generation simplicityVSAvoidtoner consumption
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

The patent resolves this contradiction by implementing dynamic pattern length generation. The control unit automatically calculates and sets the appropriate length for each test pattern based on its accumulation time requirement, eliminating the need for manual intervention or complex formatting while preventing excessive toner consumption on short-accumulation-time patterns

Inventive Principle:
Principle #15Dynamics

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 allows for more accurate calibration with reduced material consumption and improved color stability by dynamically adjusting test pattern sizes based on accumulation times, minimizing unnecessary regions and optimizing sheet usage.

Implementation Method 1

the accumulation time of light receiving elements in the color sensor is changed according to the color and density of the formed image pattern

Methodology Applied
Scientific EffectLight accumulation: Photoelectric Effect

Data Source

PatentEP2811730B1Test chart used for calibration in image forming apparatus
Publication Date: 2019.11.27 CANON KK
  • EP2811730B1 patent drawingFigure 1
  • EP2811730B1 patent drawingFigure 2
  • EP2811730B1 patent drawingFigure 3

AI summary

Multiple measurement images (test patterns A, B, C; 220) are formed in a test chart (P1-P3). Reflected light from the test patterns is received by light receiving elements of a color sensor (203) for an accumulation time (t) that is determined for the respective test patterns. The lengths (S) of the test patterns in the conveyance direction of the test chart are determined according to the lengths of the accumulation times (t) for the respective test patterns.