Image Scanner Motor Current Control for Variable Sheet Thickness
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Solution Overview
Problem
Conventional image scanning devices struggle to automatically adjust feeding speeds for sheets of varying thicknesses, especially under limited power supplies like USB, leading to inefficiencies and user inconvenience.
Innovation Solution
An image scanning device equipped with a feeding roller, a sensing roller, a contact image sensor, and springs, which automatically detects sheet thickness by measuring intervals between the rollers and adjusts feeding speeds based on recorded image read values to ensure successful scanning of sheets with different thicknesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant current value is provided to the motor to ensure sufficient torque for thicker sheets, then the feeding reliability for thick sheets is improved, but the feeding speed decreases and energy consumption increases
Solution Approach 1:
The patent applies dynamics by transitioning from constant current control to variable current control based on detected sheet thickness. The motor controller adjusts current dynamically: providing higher current for thick sheets to ensure reliable feeding, and lower current for thin sheets to maintain speed and reduce energy consumption. This resolves the contradiction by making the system adaptive rather than static.
Solution Approach 2:
The patent changes the electrical parameter (motor current) based on the physical parameter (sheet thickness). By detecting thickness first and then adjusting current accordingly, the system optimizes both feeding reliability and speed. Thick sheets receive increased current for reliable feeding, while thin sheets receive reduced current to maintain higher feeding speeds.
2Measurement precision
If manual adjustment of feeding speeds is implemented for different sheet thicknesses, then feeding accuracy is improved, but operation complexity increases
Solution Approach 1:
The patent implements self-service by enabling the system to automatically detect sheet thickness and adjust feeding parameters without user intervention. The thickness detection device and motor controller work together to autonomously optimize feeding accuracy for different sheet types, eliminating the need for manual adjustment while maintaining high precision.
Solution Approach 2:
The patent uses feedback by detecting sheet thickness and using this information to automatically adjust motor current and feeding speed. The system forms a closed-loop control where thickness measurement feeds back to the controller, which then optimizes feeding parameters, achieving high accuracy without increasing operational complexity.
3Ease of operation
If the device size is reduced for portability, then ease of carrying is improved, but the power supply capacity decreases
Solution Approach 1:
The patent optimizes power parameter usage by adjusting motor current based on actual sheet thickness requirements. Instead of providing constant high power, the system dynamically scales power consumption to match the task at hand, enabling adequate performance for thick sheets while maintaining portability through reduced average power consumption and smaller battery capacity requirements.
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
Enables efficient and automatic adjustment of feeding speeds according to sheet thickness, ensuring successful scanning even under limited power conditions, enhancing usability and scanning efficiency.
Implementation Method 1
a contact image sensor (30) mounted to the plurality of the springs. A top surface of the contact image sensor (30) faces to lower portions of outer surfaces of the feeding roller (12) and the sensing roller (13)
Data Source
AI summary
An image scanning device includes an upper shell, a feeding shaft pivotally connected to the upper shell, a feeding roller mounted around the feeding shaft, a sensing roller, a motor, a lower shell pivotally covered to the upper shell, a plurality of springs and a contact image sensor. The sensing roller is mounted around the feeding shaft. The motor is connected with the feeding shaft. The motor drives the feeding shaft to rotate in different speeds. The plurality of the springs are mounted to the lower shell. The contact image sensor is mounted to the plurality of the springs. A top surface of the contact image sensor is capable of abutting against lower portions of outer surfaces of the feeding roller and the sensing roller by virtue of the plurality of the springs elastically abutting against a bottom surface of the contact image sensor.