Image Density Control Without Patch Output
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Solution Overview
Problem
Conventional image forming apparatuses require users to output patch images to a recording medium for density gradation control in all image processing modes, which is burdensome and reduces accuracy, especially when environmental changes occur.
Innovation Solution
An image forming apparatus with a density detection unit and storage for correlations between image processing modes, allowing for accurate density gradation control without outputting patch images to the recording medium, by using a first correction parameter from one mode to derive a second correction parameter for another mode, based on detected densities and pre-stored correlations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If density gradation control is performed by outputting patch images to a recording medium in all image processing modes, then measurement precision is improved, but ease of operation deteriorates due to heavy user burden
Solution Approach 1:
The patent uses a copying approach by forming patch images on the image bearing member (photosensitive drum) and detecting their densities, then using these detected densities to calculate correction parameters. This copied measurement method on the image bearing member replaces the need for users to physically handle and measure recording media, reducing user burden while maintaining measurement precision through automated detection.
Solution Approach 2:
The system performs self-service by automatically forming patch images on the image bearing member, detecting their densities, and calculating correction parameters without requiring user intervention. The image bearing member itself serves as the measurement substrate, and the system autonomously completes the entire density gradation control process, eliminating the heavy user burden of manually outputting and measuring patch images on recording media.
2Ease of operation
If density gradation control is performed without outputting patch images to a recording medium, then ease of operation is improved, but measurement precision deteriorates
Solution Approach 1:
The patent introduces the image bearing member as an intermediary between the image processing system and the detection system. Patch images are formed on this intermediary (image bearing member) which can be easily accessed by the detection unit. This intermediary allows automated density measurement without requiring users to handle final recording media, thus maintaining measurement precision while improving ease of operation through automation.
Solution Approach 2:
The system performs preliminary density measurement actions by forming and detecting patch images on the image bearing member before actual image production. This preliminary action on the image bearing member provides the necessary density data for correction parameter calculation, enabling accurate density gradation control without requiring users to perform preliminary measurements on recording media.
3Measurement precision
If correction parameters are obtained for each image processing mode separately, then measurement precision is improved, but productivity deteriorates due to increased work required
Solution Approach 1:
The patent implements a universal correction parameter calculation mechanism where the same image bearing member detection system serves all image processing modes. The detection unit measures densities on the image bearing member regardless of the target mode, and the control unit calculates appropriate correction parameters for each mode based on these universal measurements. This multi-functional approach maintains mode-specific accuracy while improving productivity by using a single detection system for all modes.
Solution Approach 2:
The system changes parameters by using the same physical measurement process (density detection on image bearing member) but varying the correction parameter calculations based on the target image processing mode. The detection methodology remains constant, but the interpretation and application of detected densities differ by mode, enabling efficient parameter generation for multiple modes without repeating the entire measurement process for each mode.
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 method enables accurate density gradation control across multiple image processing modes without the need for user-intensive patch image output, reducing user burden and maintaining consistent image quality despite environmental changes.
Implementation Method 1
a density detection unit adapted to detect a density of the image formed on a recording medium
Data Source
AI summary
An image forming apparatus which having a plurality of image processing modes, that is capable of accurate density gradation control without performing output of any patch image to a recording medium in all the image processing modes. A first correction parameter corresponding to a first image processing mode is prepared on the basis of a result of detection, by a second density detection unit, of the image formed on a recording medium in a first image processing mode. A second correction parameter corresponding to a second image processing mode is prepared on the basis of the first correction parameter and a correlation, stored in a storage unit in advance, between density of a toner image formed on an image bearing member in the first image processing mode and density of toner image formed on the image bearing member in the second image processing mode.