Swingable Feeding Roller Optical Sensor for Sheet Detection
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Solution Overview
Problem
Existing recording apparatuses face challenges in accurately detecting the presence or absence of sheets in sheet feeding trays due to varying sheet numbers, leading to inconsistent detection accuracy and increased costs from using separate sensors for cassette and sheet detection.
Innovation Solution
A recording apparatus with a swingable feeding member that incorporates a medium detection unit, allowing for adjustable detection based on the number of sheets, using an optical sensor with adjustable light intensity and angle to maintain optimal detection regardless of sheet position, and a shared feeding roller and detection unit to reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an optical sensor is arranged at a fixed position to detect sheet presence by reflectivity change, then the detection structure is simple, but detection accuracy varies due to changing distance between sensor and sheet depending on sheet number
Solution Approach 1:
The optical sensor is mounted on the feeding roller assembly that swings between upper and lower positions. This dynamic positioning allows the sensor to automatically adjust its distance from the sheet based on the sheet stack height, maintaining optimal detection conditions regardless of whether the tray is full or nearly empty. The sensor's position changes from fixed to variable, resolving the contradiction between structural simplicity and detection accuracy.
Solution Approach 2:
The invention changes the detection parameter by making the sensor-position variable rather than fixed. By allowing the optical sensor to move with the feeding roller assembly, the system adapts the detection distance parameter to match the actual sheet position, ensuring consistent reflectivity-based detection across different sheet quantities.
2Reliability
If separate sensors are used to detect cassette mounting and sheet presence, then detection reliability is improved, but cost increases
Solution Approach 1:
The invention merges the sheet presence detection function into the existing feeding roller assembly. The optical sensor that was originally separate for sheet detection is now integrated with the feeding roller mechanism, combining multiple detection functions into a single integrated system. This reduces component count and cost while maintaining reliable detection through the dynamic positioning capability.
Solution Approach 2:
The feeding roller assembly is given multi-functionality: it serves both as the mechanical feeding mechanism and as the mounting structure for the optical sensor. This universal design allows a single assembly to perform both feeding and detection functions, eliminating the need for separate dedicated sensor mounts and reducing overall system cost.
3Measurement precision
If the light amount of reflection light is determined based on the case where number of sheets is small, then detection is accurate for empty trays, but light receiving unit may be progressively degraded when number of sheets is large
Solution Approach 1:
The optical sensor dynamically adjusts its position along with the feeding roller assembly. When sheets are present, the sensor moves to a position closer to the sheet stack, increasing the light amount received from the sheet surface. This dynamic adjustment compensates for the varying light reflection conditions across different sheet quantities, preventing degradation of detection reliability.
Solution Approach 2:
The system uses the actual light amount received from the sheet as feedback to adjust the detection threshold or sensor position. By monitoring the light reflection intensity and adapting the sensor's operational parameters accordingly, the system maintains accurate detection across varying sheet conditions without progressive degradation.
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 ensures accurate detection of sheets in both upper and lower trays by adjusting the detection angle and light intensity, reducing costs by using a single feeding member for both feeding and detection, and preventing user contact with signal lines during jam processing.
Implementation Method 1
the presence or absence of the sheet is detected by using a change in reflectivity
Data Source
AI summary
A printer includes a lower tray and an upper tray disposed above the lower tray. An optical sensor which detects the presence or absence of a sheet is disposed above the upper tray. The optical sensor is disposed in a roller support member which supports a feeding roller and serves as a swingable swing member. A distance between the optical sensor and the sheet is adjusted by swing of the roller support member according to the number of sheets.