Image Density Correction Using Sinusoidal Parameters
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Solution Overview
Problem
Existing image forming apparatuses face challenges in correcting irregular density unevenness in the subscanning direction, particularly due to rotating bodies like photoconductor and developing rollers, which can lead to periodic density variations, and require large amounts of data storage for correction tables.
Innovation Solution
An image forming apparatus that uses a sinusoidal parameter for correcting periodic density variations caused by rotating bodies and a correction table for irregular variations not caused by rotating bodies, allowing for efficient data storage and accurate density correction by calculating and retrieving correction amounts based on rotation phase and position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a correction table storing correction amounts for all positions in the subscanning direction is used, then density correction accuracy is improved, but data storage requirements increase
Solution Approach 1:
The patent segments density correction into two distinct components: periodic density variation correction handled by sinusoidal parameters and irregular density variation correction handled by a correction table. This segmentation allows the system to apply different correction methods optimized for each type of variation, reducing overall data storage requirements while maintaining correction accuracy.
Solution Approach 2:
The patent changes the representation parameters for periodic density variations from storing individual correction amounts for each position to using sinusoidal parameters (amplitude, phase, frequency). This parameter transformation dramatically reduces the data storage required for periodic corrections while maintaining the ability to accurately correct these variations.
2Reliability
If correction amounts for all density variations are stored in a correction table, then comprehensive density correction is achieved, but device complexity increases
Solution Approach 1:
The patent divides the correction system into two independent modules: a sinusoidal parameter-based correction module for periodic variations and a correction table-based module for irregular variations. This segmentation reduces system complexity by allowing each module to be optimized and processed independently, while together they provide comprehensive correction coverage.
Solution Approach 2:
The patent creates a hybrid correction system that combines two different correction approaches (sinusoidal parameter method and correction table method) into a single unified system. This multi-functional approach allows the system to handle both periodic and irregular density variations using a single integrated correction process.
Data Source
AI summary
An image forming apparatus includes: an output section that forms an electrostatic latent image onto an image carrier by using light emitted by a light source and outputs an image onto a recording medium by developing the formed electrostatic latent image; a memory that stores a sinusoidal set value representing a correction amount for correcting periodic density variations that occur in an image, which is to be formed, in a subscanning direction and that are caused by a rotating body, and a correction table in which correction amounts for correcting density variations that occur in an image, which is to be formed, in the subscanning direction and that are not caused by a rotating body are each stored in association with a corresponding position in the subscanning direction; and a processor configured to: calculate a first correction amount corresponding to a rotation phase of a rotating body included in the output section on a basis of the sinusoidal set value and retrieve a second correction amount corresponding to a position in the subscanning direction from the correction table when an image is formed in the output section; and perform, by using the calculated first correction amount and the retrieved second correction amount, correction of a density of an image that is formed onto a recording medium.