Image Reading Device Carriage Wake-Up Time Reduction
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Solution Overview
Problem
Image reading devices take a long time to return to an active mode from an energy-saving mode due to the need for homing and slow movement of carriages, which is not effectively addressed by existing techniques.
Innovation Solution
An image reading device with a control unit that switches carriage movement directions based on a home position sensor output and counts pulses to detect movement distance, allowing for efficient positioning of carriages when returning to an active mode, thereby reducing the time required to complete homing and enter the active mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the image reading device enters energy-saving mode to reduce power consumption, then power savings are achieved, but the wake-up time to return to active mode increases
Solution Approach 1:
The carriage is moved to a predetermined position (under the reference whiteboard) before entering energy-saving mode. This preliminary positioning action enables the device to skip the homing operation when waking up, thereby reducing wake-up time while maintaining energy-saving benefits
2Measurement precision
If the carriage is moved slowly to ensure precise positioning at home position, then positioning accuracy is improved, but the time required for homing operation increases
Solution Approach 1:
The carriage is preliminarily positioned under the reference whiteboard before energy-saving mode activation. This preliminary action eliminates the need for subsequent homing operations, reducing positioning time while maintaining accuracy through pulse counting for distance detection
Solution Approach 2:
The homing operation is extracted and eliminated from the wake-up sequence by using preliminary positioning. The system directly resumes operation from the predetermined position without performing the traditional homing routine, significantly reducing wake-up time
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 approach significantly reduces the time needed to return the image reading device to an active mode from an energy-saving mode by eliminating the need for homing and ensuring accurate carriage positioning, even when the carriage is not under the reference whiteboard, while maintaining adjusted gain and offset values for further speed improvements.
Implementation Method 1
a pulse motor to move the first and second carriages
Implementation Method 2
a home position sensor to detect a home position of the first carriage
Implementation Method 3
a first carriage including optical elements for reading an image of a document
Data Source
AI summary
An image reading device including a first carriage including optical elements; a second carriage including optical elements; a carriage driving unit including a pulse motor to move the first and second carriages; a home position sensor to detect a home position of the first carriage; a reference whiteboard to generate shading data and adjust a reference level to be read by the optical elements; a control unit to control the above-described components to read an image of a document through the optical elements; and a counter to count a pulse of a pulse signal driving the pulse motor. The control unit switches directions of movement of the first carriage based on a result output from the home position sensor when the image reading device is returned to an active mode from an energy-saving mode, and detects a distance of movement of the first carriage based on the pulse.