Halftone Parameter Identification for Image Density Stabilization

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Solution Overview

Problem

Existing image forming technologies face challenges in stabilizing image quality due to variations in electric charge, temperature, humidity, and sensitivity of photosensitive materials, particularly when dealing with halftone-processed image data, as methods like controlling developing conditions or modifying image data using a Gamma Look-Up Table (γLUT) are ineffective.

Innovation Solution

The solution involves identifying the halftone process parameters applied to input image data, forming a patch image using these parameters, detecting the patch image density, and adjusting image forming conditions accordingly, enabling effective stabilization even with halftone-processed data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the method of modifying image data using γLUT is used, then control response is improved, but it becomes ineffective when halftone-processed image data is inputted

Engineering Contradiction:
Improvecontrol responseVSAvoideffectiveness with halftone-processed data
Core Design Contradiction:
SpeedVSAdaptability or versatility

Solution Approach 1:

The invention changes the approach from modifying γLUT parameters to identifying halftone process parameters (such as screen frequency, screen angle, and halftone method) and applying corresponding corrections based on these identified parameters. This allows the system to adapt to halftone-processed data by detecting its characteristics and applying appropriate compensation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention performs preliminary identification of halftone process parameters applied to the input image data before forming the patch image. By detecting the halftone characteristics in advance, the system can prepare appropriate correction strategies, making the control process effective even with pre-processed halftone data.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If the method of controlling developing conditions is used, then adaptability to different conditions is improved, but control response becomes slow

Engineering Contradiction:
Improveadjustment capabilityVSAvoidcontrol response
Core Design Contradiction:
Adaptability or versatilityVSSpeed

Solution Approach 1:

The invention performs preliminary identification of halftone process parameters before patch image formation. By detecting the halftone characteristics in advance, the system can prepare appropriate correction strategies, enabling faster response while maintaining adaptability to different halftone processing conditions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention uses feedback from the detected halftone process parameters to adjust the patch image formation and subsequent image forming conditions. The density detection result feeds back to refine the correction, creating a responsive control loop that adapts to different halftone inputs while maintaining fast response.

Inventive Principle:
Principle #23Feedback

3Ease of manufacture

If patch image density detection is performed without considering halftone process parameters, then measurement simplicity is improved, but manufacturing precision deteriorates

Engineering Contradiction:
Improvedetection simplicityVSAvoidimage forming density stability
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention performs preliminary identification of halftone process parameters (screen frequency, screen angle, halftone method) before forming the patch image. This preliminary action ensures that the patch image is created with appropriate settings matching the input data's halftone characteristics, enabling accurate density detection without complicating the overall process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the patch image formation process by incorporating halftone process parameter identification. The system detects parameters such as screen frequency and screen angle, then uses these to generate a patch image that accurately reflects the halftone characteristics, improving density measurement precision while maintaining process simplicity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS7512350B2Image forming apparatus and method that identify halftone process parameter
Publication Date: 2009.03.31 CANON KK
  • US7512350B2 patent drawing
  • US7512350B2 patent drawing
  • US7512350B2 patent drawing

AI summary

An image forming apparatus appropriately adjusts an image forming conditions even if a halftone-processed image data is inputted. The image forming apparatus forms a patch image by applying a halftone process which is substantially equivalent to the halftone process which has been previously performed for the inputted image data. The image forming apparatus detects the density of the formed patch image and adjusts the image forming conditions according to the detected density.