Printer Mark Detection Using Consecutive Optical Sensor Thresholds
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Solution Overview
Problem
Existing printers that detect marks on continuous-form paper for determining the printing start position often incorrectly identify text characters or symbols as the mark, leading to inaccurate positioning during printing.
Innovation Solution
A printer system that includes a control unit, optical sensor, width information storage, and threshold value setting mechanisms to differentiate between the mark and text characters by setting specific threshold values based on the width of the mark and the size of text characters, ensuring accurate detection of the mark without mistaking text for the mark.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reflecting-type optical sensor is used to detect the mark on the reverse face of continuous-form paper, then the printing start position can be determined, but text characters or symbols may be mistakenly detected as the mark
Solution Approach 1:
The patent changes the parameter of consecutive detection count to distinguish between marks and text characters. By requiring that the same detection result occurs consecutively a predetermined number of times, the system can reliably identify marks while filtering out transient text character detections, thus resolving the contradiction between detection accuracy and reliability
Solution Approach 2:
The patent implements a feedback mechanism where the detection result is continuously monitored and fed back to the control unit. The control unit counts consecutive detections and only confirms a mark when the count reaches the predetermined threshold, providing feedback-based verification that eliminates false positives from text characters
2Difficulty of detecting and measuring
If the optical sensor detects any change in light level, then detection sensitivity is high, but false detection of text characters increases
Solution Approach 1:
The patent introduces a new parameter (consecutive detection count) that transforms the detection criterion from a single-event trigger to a multi-event confirmation process. This parameter change maintains high sensitivity by still detecting light level changes but improves precision by requiring repeated confirmation, thereby resolving the contradiction between sensitivity and accuracy
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 accurately detects the mark on the reverse face of continuous-form paper, preventing text characters from being mistakenly identified as the mark, thereby ensuring correct positioning and proper printing.
Implementation Method 1
a reflecting-type optical sensor projects light onto the reverse face of the continuous-form paper and detects reflected light that is reflected from the reverse face of the continuous-form paper
Data Source
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AI summary
In a printer 1 that is provided with an optical sensor 22, a threshold value T for determining whether a black portion that is printed on a reverse face of transported printing medium 8 is detected (Step S11). When the number of times that the optical sensor 22 has detected the black portion is greater than the threshold value T (Step S14), a declaration is made that the black portion has been detected (Step S15). Next, when the number of times that the optical sensor 22 has detected a white portion on the reverse face of the printing medium 8 is greater than the threshold value U (Step S21), a declaration is made that the white portion has been detected (Step S22). Then, a declaration is made that the mark 82 on the reverse face of the printing medium 8 has been detected.