Printing Apparatus Sheet Type Detection Using Multi-Reflectance Member
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Solution Overview
Problem
Existing printing apparatuses face challenges in accurately determining the type of printing sheets, particularly when multiple types of plain paper with similar base weights but different surface natures are used.
Innovation Solution
The printing apparatus employs a light source, a sensor to detect reflected light, a reflection member with distinct reflectance areas, and a control unit to determine the printing sheet type based on feature amounts obtained from multiple positions of the sheet during conveyance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If only transmissive optical sensor measuring quantity of transmitted light is used, then the device complexity is low, but the measurement precision for distinguishing different printing sheet types is insufficient
Solution Approach 1:
The reflection member is divided into multiple areas with different reflectance characteristics (high reflectance area and low reflectance areas). This segmentation allows the sensor to detect multiple distinct reflectance values from a single printing sheet, providing more differentiation capability for identifying different sheet types without adding multiple sensors.
Solution Approach 2:
A reflection member is introduced as an intermediary element between the printing sheet and the sensor. This reflection member with its specific multi-area reflectance pattern serves as a reference standard, enabling the sensor to indirectly determine printing sheet properties by comparing the reflected light characteristics.
2Measurement precision
If multiple sensor positions are used to detect light from different positions of the printing sheet, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
Multiple detection positions are merged into a single sensor by using a reflection member that presents multiple reflectance areas. The sensor remains stationary while the reflection member's multi-area structure provides the equivalent information that would otherwise require multiple sensors at different positions.
Solution Approach 2:
The system uses the relative motion between the conveyance mechanism and the reflection member to dynamically present different areas of the reflection member to the sensor during sheet conveyance, enabling multi-position detection capability without physically moving the sensor.
3Measurement precision
If a reflection member with multiple reflectance areas is introduced, then the measurement precision for distinguishing plain paper types improves, but the device complexity increases
Solution Approach 1:
Different areas of the reflection member are given different local qualities in terms of reflectance (high reflectance area vs. low reflectance areas). This local differentiation in reflectance properties enables the sensor to detect multiple distinct signal levels from a single sheet, providing the differentiation capability needed for identifying various plain paper types.
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 solution enables accurate determination of various printing sheet types, including detailed types of plain paper, by analyzing the reflectance patterns and opaqueness, thereby improving print control and quality.
Implementation Method 1
a light source configured to emit light to a first surface of a printing sheet; a sensor configured to detect the light reflected from the printing sheet
Implementation Method 2
a reflection member located at a position facing the sensor and coming into contact with a second surface opposite to the first surface of the printing sheet, wherein a first area and a second area whose reflectance is lower than that of the first area are included in the reflection member
Data Source
AI summary
The printing apparatus includes a light source that emits light to a first surface of a printing sheet; a sensor that detects the light reflected from the printing sheet; a reflection member located at a position facing the sensor and coming into contact with a second surface opposite to the first surface of the printing sheet; and a control unit configured to determine a type of the printing sheet based on a feature amount obtained by the sensor detecting the light from a plurality of positions of the printing sheet being conveyed, wherein a first area and a second area whose reflectance is lower than that of the first area are included in the reflection member and a position corresponding to the first area and a position corresponding to the second area are included in the plurality of positions.