Printer Edge Detection Using Ambient Light Calibration
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Solution Overview
Problem
Existing printing apparatuses face accuracy issues in sheet edge detection due to ambient light interference, leading to shifted printing start and end positions, which affects ink consumption and image quality in borderless printing.
Innovation Solution
A printing apparatus with a carriage-mounted detection unit that adjusts light emission and reception levels, and a control unit to determine and account for ambient light effects, allowing for precise sheet edge detection and minimizing extra-printing beyond the sheet edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light amount adjustment is performed before printing operation, then sensor output level can be standardized, but ambient light interference causes detection accuracy deterioration
Solution Approach 1:
The system performs preliminary calibration by detecting sheet edge positions at multiple different ambient light levels before actual printing. This preliminary detection allows the system to establish a relationship between ambient light conditions and detection results, enabling subsequent compensation during actual printing operations.
Solution Approach 2:
The system varies the light emitting unit's output intensity across multiple levels and performs sheet edge detection at each level. By collecting detection data across different light parameters, the system builds a comprehensive model that accounts for ambient light variations, allowing accurate edge detection regardless of changing ambient conditions.
2Productivity
If sheet edge detection is performed during printing, then real-time edge detection is achieved, but ambient light variations cause printing position shifts
Solution Approach 1:
The system performs preliminary sheet edge detection and ambient light characterization before the actual printing operation begins. This preliminary phase establishes baseline detection accuracy and ambient light conditions, allowing the printing process to proceed without interruption while maintaining position accuracy through pre-established calibration data.
Solution Approach 2:
The system uses the relationship between light emitting unit output and sheet edge detection results, established during preliminary calibration, to compensate for ambient light effects during printing. By applying feedback from the calibrated model, the system maintains accurate edge detection and printing position control even when ambient light conditions change during the printing process.
3Reliability
If extra-printing amount is increased to compensate for detection errors, then image quality is maintained, but ink consumption increases and waste ink collection mechanism life decreases
Solution Approach 1:
The system determines the optimal extra-printing amount by analyzing the relationship between light emitting unit output and detection results across multiple parameters. Rather than using a fixed conservative margin, the system calculates the precise extra-printing amount needed based on calibrated detection accuracy, minimizing ink waste while ensuring image quality.
Solution Approach 2:
The system applies different extra-printing amounts at different locations on the sheet based on local detection accuracy requirements. By analyzing detection results specifically at sheet edge positions and ambient light conditions, the system determines the minimum necessary extra-printing amount for each specific printing scenario, avoiding unnecessary ink consumption while maintaining image quality.
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 enhances the accuracy of sheet edge detection, reducing ink consumption and extending waste ink collection mechanism life by minimizing extra-printing, thereby ensuring high-quality borderless printing.
Implementation Method 1
a detection unit disposed on the carriage and having a light emitting unit for emitting light and a light receiving unit for making an output according to received light, the detection unit being configured to detect a sheet edge of the print sheet based on the output from the light receiving unit when the light emitting unit emits light to the print sheet
Data Source
AI summary
A printing apparatus includes a conveyance unit configured to convey a sheet in a conveyance direction, a print unit configured to perform printing on the sheet conveyed by the conveyance unit, a light receiving unit configured to receive light and make an output according to the received light, and a control unit configured to control borderless printing by the print unit, the borderless printing including extra-printing from a sheet edge to outside of the sheet. The control unit sets an extra-printing amount by which printing extends off the sheet edge after the light receiving unit makes the output according to the received light.