Signal Processing Apparatus for Image Forming with Signal Width Correction
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately canceling differences between actual and ideal image creating signals, particularly due to fluctuations caused by environmental and circuit variations, which affect image density and resolution, and current correction methods are inadequate for high image resolution and low gradation scenarios.
Innovation Solution
A signal processing apparatus that measures the difference between actual and ideal signal widths of image creating signals and corrects image data in real-time by adjusting pixel states or their surrounding pixels, using asynchronous measurement clocks to ensure accurate cancellation of signal width discrepancies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional gamma correction is used to correct density level changes, then image formation can be performed for photographic and character images, but it becomes difficult to deal with high image resolution and low gradation scenarios
Solution Approach 1:
The invention divides the image data into multiple pixels to express a single gradation level. Instead of using conventional gamma correction that operates on individual pixels, the patent segments each gradation level across multiple pixels (e.g., a 2-bit gradation is expressed by 4 pixels). This segmentation approach enables high-resolution imaging while maintaining gradation expression capability, as the gradation is determined by the pattern of multiple pixels rather than individual pixel values.
2Productivity
If PWM signals are used for image creation, then image formation can be performed efficiently, but signal width fluctuation due to environmental factors causes density level changes
Solution Approach 1:
The invention introduces a feedback mechanism where the actual signal width of the PWM signal is measured and compared with the ideal signal width. Based on the measured difference, the image data is corrected to compensate for the signal width deviation. This feedback loop ensures that density level changes caused by environmental factors are compensated, maintaining image quality while using efficient PWM-based image formation.
Solution Approach 2:
The invention performs preliminary correction of image data based on pre-measured signal width differences. Before actual image formation, the system measures the signal width characteristics and uses this information to pre-adjust the image data. This preliminary action ensures that when PWM signals are generated for image formation, the density levels are already compensated for expected variations, maintaining precision without sacrificing efficiency.
3Adaptability or versatility
If the actual value of image creating signal differs from theoretical value, then circuit variations and environmental factors are accommodated, but density level changes occur on formed images
Solution Approach 1:
The system measures the actual signal width of PWM signals and compares it with the ideal value. Based on this feedback, the image data is corrected to compensate for the difference. This feedback mechanism allows the system to adapt to circuit variations and environmental factors while maintaining accurate density levels in the formed images.
Solution Approach 2:
The invention changes the parameter of image data (specifically, the distribution of pixel states) based on the measured signal width difference. When the actual signal width differs from the ideal value, the system adjusts the image data parameters to compensate, such as modifying the ratio of ON/OFF pixels or adjusting the pattern of multiple pixels that represent each gradation level. This parameter adjustment maintains density accuracy despite hardware variations.
Data Source
AI summary
A signal processing apparatus includes a pulse signal producing section configured to produce image creating signals for image formation in response to image data by using an image processing clock corresponding to each pixel of the image data; a measuring section configured to measure a difference between an actual value and an ideal value of a signal width of the image creating signal at the time of measurement; and a processing section configured to correct the image data so as to cancel the difference at the time of an actual action.