Print Media Conveyance Correction Using Optical Sensor Feedback
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Solution Overview
Problem
Existing printing apparatuses face challenges in accurately conveying print media due to variations in material, color, and surface properties, leading to inconsistencies in position detection by optical sensors.
Innovation Solution
An apparatus and method that utilize a conveyance roller, print unit, platen, sensor, and control unit to correct the conveyance amount based on detected values before and after the print medium enters the sensor's light irradiation region, enhancing detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an optical sensor is used to detect the position of the print medium, then the detection process is simple and fast, but the detection accuracy varies due to different print medium characteristics
Solution Approach 1:
The patent implements feedback by acquiring a first detected value before the print medium reaches the light irradiation region and a second detected value after the print medium is conveyed to include the light irradiation region. The control unit calculates the difference between these two values to determine a conveyance correction amount, which is then applied to correct the conveyance amount. This feedback mechanism compensates for detection inaccuracies caused by varying print medium characteristics.
Solution Approach 2:
The patent replaces direct mechanical position detection with an optical detection system. Instead of using mechanical sensors that physically contact the print medium, the system uses light emission and detection to measure position indirectly. The optical sensor detects changes in light transmission as the print medium passes through the light irradiation region, converting optical information into position data for correction purposes.
2Manufacturing precision
If the conveyance amount is not corrected, then the system operation is simple, but the printing position accuracy deteriorates
Solution Approach 1:
The control unit uses feedback from the optical sensor to calculate a conveyance correction amount based on the difference between the first and second detected values. This correction amount is applied to adjust the conveyance amount, ensuring accurate printing position without requiring complex mechanical adjustment mechanisms.
Solution Approach 2:
The system changes the parameter being controlled from direct mechanical conveyance distance to a corrected conveyance amount based on optical detection data. By adjusting the conveyance amount parameter based on detected value differences, the system achieves precise printing positioning while maintaining relatively simple hardware architecture.
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
Improves the accuracy of print medium conveyance and positioning, ensuring precise printing on various types of media, including thick sheets, by correcting the conveyance amount using optical sensor feedback.
Implementation Method 1
a sensor configured to emit light to the platen and detect light from the platen
Data Source
AI summary
An apparatus comprising a conveyance roller configured to convey a print medium, a print unit configured to execute printing on the print medium, a platen arranged to face the print unit and configured to support the print medium, a sensor configured to emit light to the platen and detect light from the platen, and a control unit configured to execute first control of acquiring, as a first value, a detected value before the print medium reaches a light irradiation region of the sensor, and acquiring, as a second value, a detected value after the print medium is conveyed to include the light irradiation region, wherein the control unit further execute second control of correcting a conveyance amount of the print medium by the conveyance roller based on the first value and the second value.