Media Stack Height Sensor Assembly Tolerance Reduction
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Solution Overview
Problem
Existing media stack height sensors in staplers have large stack up tolerance and delays in operation, and are unable to accurately determine the number of media sheets to be stapled, as they rely on rotating links and optical beam sensors which are prone to errors and uncertainties.
Innovation Solution
A stack height sensor assembly with a support, drive assembly, and insertion assembly, featuring a reversible motor, a plunger with a sensor, and a probe biased by a spring, which extends and retracts to measure the media stack height accurately and provide a signal to the controller, allowing for precise determination of the media stack height and sheet count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rotating link driven by a solenoid is used for height measurement, then the device can detect media stack height, but the system experiences large stack up tolerance and delays in operation
Solution Approach 1:
The patent replaces the mechanical rotating link and solenoid system with an optical sensor system. The optical sensor detects media stack height by measuring the reflection of light from the media surface, eliminating mechanical moving parts and solenoid actuation delays. This substitution provides faster response time and eliminates operation delays while improving measurement precision through optical detection capabilities.
2Reliability
If a rotating link with optical beam sensor is used, then media stack height can be detected, but the system has large stack up tolerance and uncertainty in operation
Solution Approach 1:
The patent replaces the mechanical rotating link system with a direct optical sensor assembly that maintains a fixed optical path. This eliminates mechanical tolerance accumulation and uncertainty associated with rotating link positioning. The optical sensor provides reliable and precise measurements by directly detecting light reflection from the media surface without mechanical intermediate components.
3Loss of information
If a rotating link system is used for height measurement, then basic height detection is possible, but the actual number of media sheets cannot be determined
Solution Approach 1:
The patent implements a feedback system where the optical sensor continuously monitors media stack height and provides real-time information to the control system. By measuring the optical path length and light reflection characteristics, the system can calculate both the height of the media stack and infer the number of sheets. This feedback mechanism eliminates information loss about media sheet count while maintaining high measurement precision through continuous optical detection.
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
The solution minimizes stack up tolerance, eliminates uncertainties in stapler operation, and enables accurate measurement of the media stack height and sheet count, ensuring reliable stapling without jamming or damage to the stapler head.
Implementation Method 1
a biasing member connected the probe and to the plunger wherein the probe is biased such that a portion of the probe at the bottom end thereof extends a predefined distance below the bottom end of the plunger
Data Source
AI summary
A translateable media height sensor assembly for measuring a media stack height in an imaging forming device. The assembly includes a support and drive and insertion assemblies mounted thereon. The insertion assembly includes a translateable plunger having mounted thereon a sensor and a translateable probe. At a home position the sensor is actuated by a flag on the support placing sensor output in a first state. During measurement, the drive assembly translates the insertion assembly toward a media stack and the sensor output changes to a second state and a counter is started. The probe encounters the media stack and stops while the plunger and the sensor continue to translate with the probe engaging the sensor causing the sensor output to again change state and stop the counter. The insertion assembly retracts back to the home position where the flag actuates the sensor causing the sensor output to change state.