Image Abnormality Detection in Electrophotographic Apparatus
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Solution Overview
Problem
Conventional methods for identifying failure points in electrophotographic image forming apparatuses are inaccurate due to variations in sheet conveyance timing, which affect the detection of periodic image abnormalities, especially when the periodicity of issues like a damaged photosensitive drum occurs at intervals longer than the sheet conveyance direction, leading to incomplete data analysis.
Innovation Solution
An image forming apparatus and method that continuously conveys sheets with a sheet detection sensor and image reader to analyze image abnormalities, estimating the conveyance interval and determining periodicity based on the detection results, allowing for precise identification of failure points without being influenced by sheet conveyance timing variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the theoretical distance between sheets is used for analysis, then the analysis process is simple, but the accuracy of detecting image abnormality periodicity deteriorates due to sheet conveyance timing variations
Solution Approach 1:
The system uses sheet detection sensors to provide feedback on actual sheet conveyance timing, which is then used to dynamically adjust the distance between sheets in the analysis process. This feedback mechanism ensures that the analysis reflects actual conveyance conditions rather than relying on fixed theoretical values.
Solution Approach 2:
The distance between sheets is changed from a fixed theoretical parameter to a dynamic parameter that is adjusted based on actual sheet conveyance timing detected by sensors. This parameter change allows the system to adapt to variations in sheet handling and maintain accurate periodicity detection.
2Loss of time
If a single sheet is used for analysis, then the processing time is short, but the sufficiency of data for analyzing long periods deteriorates
Solution Approach 1:
The system merges read image data from multiple sheets into a single continuous analysis dataset. By combining data from multiple sheets and using the adjusted distance between sheets to maintain correct spatial relationships, the system achieves sufficient data length for analyzing long periods while keeping processing efficient.
Solution Approach 2:
The analysis transitions from examining individual sheets in isolation to analyzing a continuous multi-sheet dataset. This dimensional change from single-sheet to multi-sheet continuous analysis provides sufficient data length for detecting long-period abnormalities while maintaining processing efficiency through integrated analysis.
3Reliability
If a margin is provided to the distance between sheets to account for timing variations, then the reliability of analysis is improved, but the accuracy of periodicity detection deteriorates
Solution Approach 1:
Instead of using a fixed margin, the system implements feedback-based dynamic adjustment of the distance between sheets. Sheet detection sensors provide real-time information about actual conveyance timing, allowing the system to precisely adjust distances without introducing the accuracy degradation that fixed margins cause.
Solution Approach 2:
The distance between sheets transitions from a static value (theoretical distance or theoretical distance plus fixed margin) to a dynamic value that is continuously adjusted based on actual sheet conveyance timing. This dynamic approach maintains both reliability and accuracy by adapting to actual conditions rather than using fixed compensations.
Data Source
AI summary
An image forming apparatus, including: an image former; a sheet detection sensor; an image reader; and a hardware processor that: detects an image abnormality by analyzing the read image data and obtains a position in a sheet conveyance direction of the detected image abnormality in the read image data for each piece of the read image data corresponding to each of the sheets; estimates a conveyance interval of the plurality of sheets based on a detection result by the sheet detection sensor, and determines whether a specific periodicity exists based on the estimated conveyance interval and the position of the image abnormality detected from the read image data corresponding to each of the sheets; and when the specific periodicity is determined to exist, estimates a part corresponding to the specific periodicity as a failure point.