Print Apparatus End Position Detection with Convexity Compensation
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Solution Overview
Problem
Existing print apparatuses face challenges in accurately detecting the end positions of a print medium when these positions overlap with the positions of convexities, such as ribs, due to abrasion leading to false detection caused by changes in light reflectance.
Innovation Solution
A print apparatus with a non-contact detection unit and a control unit that determines the end position of the print medium by comparing the detected end position with a theoretical position based on information about the medium, and adjusts detection methods to account for overlapping and abrasion, ensuring accurate detection even when the end position overlaps with convexities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a non-contact sensor is used to detect end positions of paper during carriage scanning, then the end position detection function is enabled, but false detection occurs when end positions overlap with convexities due to abrasion-induced light reflectance changes
Solution Approach 1:
The system performs preliminary action by storing the theoretical positions of convexities in advance and using them to predict and correct potential detection errors. Before final determination of end positions, the control unit checks whether detected positions coincide with stored convexity positions, and if so, adjusts the detection results based on predetermined relationships between convexity positions and actual end positions.
Solution Approach 2:
The control unit implements feedback by continuously monitoring the relationship between detected end positions and stored convexity positions. When a coincidence is detected (indicating potential false detection), the system feedback-adjusts the end position determination by calculating actual end positions based on the known convexity positions and predetermined spatial relationships, thereby correcting the false detection.
2Ease of operation
If convexities are arranged to support paper during conveyance, then paper support function is achieved, but light reflectance changes due to abrasion cause false detection signals
Solution Approach 1:
The system extracts the harmful effect of convexity light reflectance changes by separating the detection function from the support function. The control unit identifies when end position detections coincide with convexity positions and excludes these false signals, effectively removing the harmful interference while preserving the necessary paper support function.
Solution Approach 2:
The stored convexity position data acts as an intermediary that mediates between the physical convexities (which cause false detection) and the detection system. By introducing this intermediate layer of known position information, the system can distinguish between true end positions and false signals generated by convexity light reflectance changes.
3Measurement precision
If ribs are positioned to essentially not overlap with side ends of fixed-form paper, then false detection is minimized under ideal conditions, but skewing or positional displacement causes overlap and subsequent false detection
Solution Approach 1:
The system applies dynamics by transitioning from a static rib positioning approach to a dynamic detection correction approach. Instead of relying on fixed rib positions to prevent all false detections, the control unit dynamically adjusts end position determinations based on real-time comparison between detected positions and stored convexity positions, enabling adaptation to various paper positioning scenarios including skewing and displacement.
Solution Approach 2:
The system changes parameters by using predetermined relationships between convexity positions and actual end positions to adjust detection results. When detection parameters indicate coincidence with convexity positions, the control unit modifies the end position parameters based on the stored convexity position data and known spatial relationships, thereby correcting false detections caused by paper position variations.
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 configuration allows for more accurate determination of the print medium's end positions, reducing detection time and preventing false positives, thereby improving the reliability and efficiency of the printing process.
Implementation Method 1
a non-contact sensor (for example, an optical sensor) provided to the carriage to sense ends (side ends) of the paper in the direction of scanning by receiving reflected light of light that has been irradiated towards the paper side by the sensor during the scanning of the carriage
Data Source
AI summary
A print apparatus includes a conveyance unit configured to convey a print medium over a plurality of convexities that are arranged along a direction of scanning and the control unit. When one end position of the print medium has been detected by a detection unit, in a case where the one end position is a position that overlaps with position of the convexities stored in a storage unit, the control unit is configured to control a detection of the other end position of the print medium and determine the one end position on the basis of the other end position.