Image Forming Apparatus Line-Screen Correction for Density Uniformity
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Solution Overview
Problem
Existing image forming apparatuses fail to adequately address density unevenness in the main scanning direction, particularly when different line screens are used for toner patterns and images, leading to residual density inconsistencies.
Innovation Solution
The apparatus incorporates a detector to identify density unevenness, calculates a first correction amount, and applies a second correction based on the difference between line screens, using a gradation correction table to adjust image data accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a correction amount is calculated based on density unevenness detected from a toner pattern formed with a first line screen, then density unevenness can be reduced for that specific line screen, but density unevenness remains when a different second line screen is used for forming the toner image
Solution Approach 1:
The patent applies parameter changes by storing multiple correction amounts corresponding to different line screens and selecting the appropriate correction amount based on the line screen parameter used for image formation. This allows the system to adapt the correction parameters to match the specific line screen being used, thereby maintaining density uniformity across different line screen configurations.
Solution Approach 2:
The patent implements preliminary action by pre-calculating and storing correction amounts for multiple different line screens before actual image formation. When a toner pattern is formed, the system determines the line screen parameter and retrieves the corresponding pre-prepared correction amount, enabling immediate application of the appropriate correction without requiring real-time recalculation.
2Productivity
If the correction amount is determined solely from the first line screen used for the toner pattern, then the correction process is simple and fast, but image quality deteriorates when different line screens are used
Solution Approach 1:
The patent performs correction amounts calculation in advance for multiple line screens and stores them in memory. During actual operation, the system only needs to retrieve the pre-calculated correction amount corresponding to the current line screen parameter, maintaining fast processing speed while ensuring accurate correction for any line screen configuration.
Solution Approach 2:
The system changes the correction parameter based on the line screen parameter detected from the toner pattern. By storing multiple correction amounts corresponding to different line screen parameters and selecting the appropriate one, the system maintains both processing efficiency and image quality consistency across different line screens.
Data Source
AI summary
An image forming apparatus includes an image former, a detector, and circuitry. The image former forms a toner pattern with a first line screen; and forms a toner image based on image data, with a second line screen. The detector detects density unevenness of the toner pattern, formed by the image former, in a main scanning direction. The circuitry is configured to calculate a first correction amount from the density unevenness detected by the detector; create a gradation correction table that reduces the density unevenness based on the first correction amount; and correct the first correction amount by a second correction amount corresponding to the second line screen, in a case where the first line screen is different from the second line screen.