Sheet Detection Sensor Array Gap Error Compensation
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Solution Overview
Problem
Conventional image forming apparatuses face challenges in accurately detecting the widthwise size of a sheet due to variations in intervals between sensor blocks, leading to errors in sheet position measurement, which is critical for high-precision printing, especially in double-sided printing modes.
Innovation Solution
The implementation of a sheet detection sensor system that includes interpolation pixels to compensate for differences in sensor element intervals, allowing for accurate correction of detected sheet width errors by inserting pseudo pixels into shaded image data, thereby reducing discrepancies between detected and actual sheet sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a multi-sensor array is used to detect sheet width position, then detection coverage is improved, but measurement precision deteriorates due to variations in intervals between sensor blocks
Solution Approach 1:
The system performs preliminary measurement of actual intervals between sensor blocks during setup or calibration, storing these values for later compensation. This preliminary action enables the system to pre-know the exact positioning characteristics of each sensor block, which is then used to correct detection results and eliminate measurement errors caused by interval variations.
Solution Approach 2:
The system changes the parameter representation by introducing interpolation pixels that transform discrete sensor block intervals into a continuous coordinate system. By calculating virtual pixel positions based on actual sensor intervals and storing these as reference data, the system transforms the measurement parameter from discrete sensor readings to continuous corrected coordinates, thereby eliminating the impact of interval variations on measurement precision.
2Device complexity
If sensor blocks are arranged with larger intervals to reduce complexity, then device complexity is reduced, but measurement precision deteriorates due to gaps between sensors
Solution Approach 1:
The system introduces interpolation pixels as intermediary elements between actual sensor blocks. These virtual pixels act as mediators that fill the gaps between physical sensors, allowing the system to maintain larger physical intervals (reducing complexity) while preserving continuous position detection capability (maintaining precision). The interpolation pixels calculate intermediate positions based on adjacent sensor readings, effectively bridging the gaps without requiring additional physical sensors.
3Device complexity
If conventional sheet detection is used without compensation, then device complexity is low, but manufacturing precision deteriorates due to uncorrected detection errors
Solution Approach 1:
The system implements a feedback mechanism where actual sensor block intervals are measured and stored, then used to generate compensation data that corrects detection results in real-time. The corrected position information feeds back into the printing control system, allowing continuous adjustment and correction of print positions based on actual sensor characteristics, thereby improving manufacturing precision through automated feedback-based compensation.
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 solution enables precise correction of sheet width errors, enhancing print position accuracy to meet high demands for double-sided printing, ensuring accurate alignment and preventing ink ejection into outer areas of the sheet.
Implementation Method 1
a CIS (Contact Image Sensor) for detecting widthwise-end positions of a sheet is provided on a conveyance belt that conveys the sheet. In this case, the image forming apparatus detects a widthwise-end position of a sheet on a basis of intensity differences of light received by the CIS due to presence or absence of the sheet.
Data Source
Figure 1
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Figure 4~5
AI summary
An image forming apparatus (100) includes a conveyance part (5), an image forming part (9), a sheet detection sensor (60), a sensor unit (51), and a controller (74). The sheet detection sensor (60), in which a plurality of sensor blocks (60b) each with a plurality of sensor elements (60a) mounted thereon at specified intervals are arrayed in a sheet width direction, detects an edge position in the sheet width direction on a basis of scanning image data formed by reading of the sheet. The controller (74) is enabled to execute a calibration of inserting, into the scanning image data, interpolation pixels (Ip) for compensating an error between an edge position detected by the scanning image data and an actual edge position.