Printer Paper Width Detection Using Light Intensity Thresholds
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Solution Overview
Problem
Image forming apparatuses, such as inkjet printers, face printing failures due to false paper width detection caused by foreign objects like paper dust, leading to image offset or contamination.
Innovation Solution
An image forming apparatus that includes a detection unit emitting light on a recording medium or platen, a width calculation unit comparing light intensity with a threshold to determine the medium's width, and an image formation control unit halting operations if the detected width is less than a predefined value, preventing incorrect image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a paper detection sensor is used to detect paper edge position, then image positioning accuracy is improved, but false detection caused by foreign objects like paper dust leads to printing failures
Solution Approach 1:
The system changes the detection parameter from simple presence/absence to measuring the width of the detected object. By calculating the width of the paper based on detection positions and comparing it with expected paper width ranges, the system can distinguish between actual paper edges and foreign objects like paper dust, thereby resolving the contradiction between detection precision and reliability
Solution Approach 2:
The system implements feedback by using the detected paper width information to verify detection validity. When the calculated paper width falls outside the expected range, the system identifies this as a false detection and takes corrective action, thus improving detection reliability while maintaining the precision of edge position detection
2Measurement precision
If the detection unit scans the entire width to accurately measure paper width, then measurement precision is improved, but the detection time increases
Solution Approach 1:
The system performs preliminary detection by scanning from one edge of the paper to identify the first detection position, then scans to the other edge to identify the second detection position. By stopping the scan at these critical points rather than continuously scanning the entire width, the system achieves accurate width measurement while minimizing detection time
Solution Approach 2:
The detection process is segmented into distinct phases: scanning from the first edge to find the detection start position, scanning to the second edge to find the detection end position, and then calculating width based on these positions. This segmentation allows the system to obtain precise width measurements without requiring continuous scanning of the entire paper width, thus reducing detection time
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
Prevents printing failures by accurately determining the paper width and halting image formation when foreign objects are detected, ensuring proper image positioning and avoiding contamination.
Implementation Method 1
a detection unit that emits light on a recording medium or a platen and detects light reflected from the recording medium or the platen
Data Source
AI summary
An image forming apparatus includes a detection unit that emits light on a recording medium or a platen and detects reflected light while the detection unit moves in a direction perpendicular to a transportation direction of the recording medium; a width calculation unit that compares a value indicative of light intensity responsive to the reflected light with a threshold, and calculates a width of the recording medium measured from a position of the detection unit where the value indicative of light intensity responsive to the reflected light becomes greater than or equal to the threshold; an image formation unit that performs an operation of forming an image based on the calculated width of the recording medium; and an image formation control unit that halts the operation of forming the image upon detecting that the calculated width is less than or equal to a predefined value.