Sheet Feeding Device Variable Resistor Lift Shaft Detection
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Solution Overview
Problem
Existing sheet feeding devices have a large and complex mechanism for detecting the remaining amount of sheets, which results in rough detection and poor user awareness of the sheet levels, especially due to the placement of indicating pieces on the side face of the cassette.
Innovation Solution
A sheet feeding device incorporating a rotary variable resistor that changes electric resistance values based on the rotating angle of the lift member's shaft, allowing for precise calculation and display of sheet amounts on an operation panel, enabling detailed detection and display of remaining sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mechanism using an actuator and two sensors is used to detect the rotating angle of the rotating shaft, then the remaining amount of sheets can be detected, but the mechanism becomes large in size and the number of parts increases
Solution Approach 1:
The invention extracts the detection function from a complex mechanical mechanism and integrates it directly into the rotating shaft itself by forming a conductive pattern on an insulating coating layer. This eliminates the need for separate actuators and sensors, reducing part count while maintaining detection capability.
Solution Approach 2:
The invention replaces the mechanical detection system (actuator and sensors) with an electrical detection system using a variable resistor formed by a conductive pattern on an insulating coating. This substitution simplifies the mechanism while enabling precise measurement of the rotating shaft's angular position.
2Device complexity
If an indicating piece is provided on a side face of the sheet feeding cassette, then the structure is simple, but the user hardly recognizes the remaining amount of sheets
Solution Approach 1:
The invention introduces an intermediary system (operation panel with display) between the detection mechanism and the user. The variable resistor detects the sheet level, and this information is transmitted through the control unit to the operation panel, which clearly displays the remaining sheet amount to the user, ensuring accurate information delivery.
3Measurement precision
If two sensors are used to detect the actuator at predetermined intervals, then the rotating angle can be detected at multiple steps, but the mechanism becomes complex and detection precision is limited
Solution Approach 1:
The invention segments the detection function into multiple conductive patterns arranged at different angular positions on the insulating coating layer. Each conductive pattern corresponds to a specific angular position, allowing the system to detect the rotating shaft's angle at multiple discrete steps by determining which conductive pattern is currently contacting the variable resistor element.
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 allows for finer step detection of sheet amounts with a simpler and more compact structure, improving user awareness and operational efficiency.
Implementation Method 1
a variable resistor which changes an electric resistance value depending on a rotating angle of the rotating shaft
Data Source
AI summary
A sheet feeding device (4) includes a placing plate (34) on which a sheet is placed; a pickup roller (71) which feeds the sheet to a conveying path (25); a lift member (36) which is turned around a rotating shaft (46) to elevate the placing plate (34) and to make an downstream side end portion of an uppermost sheet in a conveying direction come into contact with the pickup roller (71); a drive unit (37) which rotates the rotating shaft (46); a variable resistor (54) which changes an electric resistance value depending on a rotating angle of the rotating shaft (46); and a control part (77) which calculates the rotating angle of the rotating shaft (46) using the electric resistance value measured by the variable resistor (54) and detects an amount of the sheets based on the calculated rotating angle.