Printer Mark Detection Using Variable Threshold Calibration
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Solution Overview
Problem
Printers struggle to accurately detect the position of marks on tapes due to variations in print density and reflectivity, leading to false detections.
Innovation Solution
A printer system that includes a conveyor, a print head, a reflection sensor, and a controller, where the controller sets a variable threshold based on the detection signal from a second mark to accurately identify the position of a first mark, regardless of print density and reflectivity variations, by using a second mark with a lower coloring ratio and distinct pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed threshold is used for mark detection, then the detection process is simple, but false detections occur due to variations in print density and reflectivity
Solution Approach 1:
The patent applies the dynamics principle by making the detection threshold variable rather than fixed. The controller dynamically adjusts the threshold based on the detection signal level from the second mark, allowing the system to adapt to variations in print density and tape reflectivity. This resolves the contradiction by maintaining detection simplicity while improving reliability through adaptive thresholding.
Solution Approach 2:
The patent implements parameter changes by modifying the threshold parameter based on detected conditions. The threshold is changed from a fixed value to a variable value determined by the detection signal level from the second mark. This parameter adaptation enables accurate mark detection across varying print densities and reflectivity conditions without complicating the overall detection process.
2Ease of operation
If a single solid mark is used for position detection, then detection is straightforward, but detection accuracy is affected by print density variations
Solution Approach 1:
The patent applies segmentation by dividing the mark detection function into two distinct marks: a first solid mark for straightforward position identification and a second patterned mark for threshold calibration. The second mark is segmented into a striped or dot pattern with lower coloring ratio, enabling separate optimization of each mark's function while improving overall detection accuracy.
Solution Approach 2:
The second mark serves as an intermediary element that mediates between the detection system and the first mark. By detecting the second mark's pattern and using its signal level to set the threshold, the system creates an intermediate reference point that compensates for print density variations, thereby improving the accuracy of first mark detection without complicating the process.
3Stability of the object's composition
If the second mark has the same coloring ratio as the first mark, then both marks are uniformly detectable, but the threshold cannot be accurately calibrated
Solution Approach 1:
The patent implements local quality by giving each mark different coloring characteristics suited to its specific function. The first mark maintains uniform solid coloring for stable position reference, while the second mark uses a striped or dot pattern with lower coloring ratio for accurate threshold calibration. This localized differentiation of mark properties enables both marks to perform their respective functions optimally.
Solution Approach 2:
The patent applies asymmetry by creating intentional differences between the two marks in terms of coloring ratio and pattern. The second mark's asymmetric design (striped or dot pattern with lower coloring) contrasts with the first mark's uniform solid appearance, enabling the system to distinguish between calibration and detection functions while improving measurement precision.
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
The system ensures precise detection of the first mark's position without being affected by print density and reflectivity changes, preventing false detections and allowing for in-line inspection of printed marks.
Implementation Method 1
a reflection sensor configured to detect the plurality of marks on the tape by emitting light toward the tape and receiving reflected light from the tape
Data Source
AI summary
A printer includes a conveyor to convey a tape having a plurality of marks in a conveyance direction, the marks including a first mark, and a second mark formed downstream of the first mark in the conveyance direction, a print head to print an image on the tape, a reflection sensor to detect the marks on the tape by emitting light toward the tape and receiving reflected light from the tape, and output a detection signal according to the reflected light when detecting the marks, and a controller. The controller is configured to set a threshold to be variable based on a level of the detection signal when the reflection sensor detects the second mark, and identify a position of the first mark based on a result of comparison between the threshold and a level of the detection signal when the reflection sensor detects the first mark.