Printing Apparatus Double-Sided Detection Control
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Solution Overview
Problem
Existing printing apparatuses incorrectly determine the end of a medium during double-sided printing due to low reflectance on the back surface, leading to unnecessary stopping of the printing process.
Innovation Solution
A printing apparatus with a detection unit that emits light on the back surface and a control unit that continues printing based on a predefined range corresponding to the image printed on the back surface, reducing incorrect end detection by using a second detection unit to determine the printing range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the paper end sensor emits light to detect the rolled sheet in the transport guide unit, then the existence of the medium can be detected, but when the reflectance on the back surface is low, the reflected light cannot be detected correctly, leading to incorrect determination that no medium exists
Solution Approach 1:
The system performs preliminary detection of the medium's back surface by emitting light through the transport guide unit before the medium reaches the printing unit. This preliminary action allows the control unit to determine whether the medium exists in advance, preventing incorrect stoppage when the medium is present but has low reflectance on its back surface.
Solution Approach 2:
The transport guide unit acts as an intermediary medium between the light source and the medium being detected. By emitting light through the transport guide unit, the system can detect the medium's presence without directly contacting or illuminating the low-reflectance back surface, thus avoiding detection failures.
2Reliability
If the printing apparatus stops printing when the paper end sensor detects no rolled sheet, then printing can be prevented on missing medium, but incorrect determination leads to unnecessary stopping during double-sided printing
Solution Approach 1:
The control unit performs preliminary detection of the medium's presence through the transport guide unit before initiating or continuing the printing process. This preliminary action allows the system to distinguish between actual medium absence (requiring stoppage) and false detection due to low reflectance (where printing should continue), thereby preventing unnecessary stopping while maintaining printing reliability.
Solution Approach 2:
The system uses feedback from the light detection through the transport guide unit to continuously monitor medium presence. When the detection indicates no medium, the control unit verifies this feedback against the expected printing state (particularly for double-sided printing), and only stops printing if the absence is confirmed, preventing premature termination due to false feedback.
3Device complexity
If the control unit determines the second range based on the length of the first image, then control load is reduced, but the detection accuracy may be affected by reflectance variations
Solution Approach 1:
The control unit performs preliminary determination of the second range based on the stored length information of the first image before actual detection occurs. This preliminary action pre-calculates the expected detection range, allowing the system to compare actual detection results against this pre-established boundary, thereby maintaining detection accuracy while reducing real-time control complexity.
Solution Approach 2:
The system creates a virtual copy of the first image's spatial characteristics (its length and position) to define the second range on the front surface. This copied information allows the control unit to determine the expected detection area without physically measuring or complexly processing the actual medium, simplifying control while maintaining precision through the copied geometric data.
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 reduces unnecessary stopping of the printing process by continuing to print irrespective of the detection result when the second image is within the defined range on the front surface, improving detection accuracy and reducing control load.
Implementation Method 1
a detection unit that receives reflected light of light emitted on a back surface of the medium transported in a detecting position
Data Source
AI summary
A printing apparatus includes a printing unit that prints on a front surface of a medium, a detection unit that receives reflected light of light emitted on a back surface of the medium, and a control unit that stops printing based on a detection result of the detection unit. In a case in which a second image is to be printed on the front surface of the medium of which back surface a first image being printed, when a range in which the first image is printed on the back surface of the medium is defined as a first range and a range corresponding to the first range on the front surface of the medium is defined as a second range, when printing the second image in the second range, the control unit continues printing irrespective of the detection result of the detection unit.