Dual-Motor Image Scanner with Torque-Limited Reverse Roller
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Solution Overview
Problem
Conventional image reading apparatuses face inefficiencies in sheet separation and reading speed, leading to decreased image reading efficiency due to limitations in the ratio of circumferential speeds of separation and feed rollers, resulting in potential unloaded feed and delayed start of subsequent sheet reading.
Innovation Solution
The image reading apparatus employs separate motors for the feed and conveyance rollers, with a reverse roller using a torque limiter to maintain optimal separation performance by varying circumferential speeds during different operational phases, ensuring the feed roller operates at sufficient speed to prevent unloaded feed and allowing for simultaneous sheet separation and conveyance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single motor drives both feed roller and conveyance roller with clutch, then device complexity is reduced, but sheet separation performance deteriorates due to limited speed ratio control
Solution Approach 1:
The single motor system is segmented into two independent motors: first motor driving feed roller and second motor driving conveyance roller. This segmentation allows independent control of each roller's speed, enabling optimal speed ratio control for sheet separation while maintaining separate drive functions.
Solution Approach 2:
The system dynamically adjusts the circumferential speeds of feed roller and conveyance roller independently through separate motor control. The feed roller can operate at high speed for feeding while conveyance roller operates at controlled speed for reading, with dynamic speed ratio adjustment based on reading resolution requirements.
2Productivity
If feed roller operates at high speed to prevent unloaded feed, then productivity is improved, but reading speed must be reduced requiring slower conveyance roller speed
Solution Approach 1:
The drive system is segmented into independent first motor for feed roller and second motor for conveyance roller, allowing simultaneous optimization of feed speed and reading speed without mutual constraint. Feed roller can run at high speed while conveyance roller maintains appropriate reading speed.
Solution Approach 2:
The system changes operational parameters by independently controlling the circumferential speeds of feed roller and conveyance roller. Different speed combinations are applied based on reading resolution requirements, with feed roller speed optimized for preventing unloaded feed and conveyance roller speed optimized for reading performance.
3Reliability
If reverse roller speed is increased to improve sheet separation, then separation performance is improved, but energy consumption increases
Solution Approach 1:
The system optimizes the circumferential speed parameter of reverse roller based on operational phase. During sheet feeding, reverse roller operates at speed optimized for separation; during conveyance, speed is adjusted to maintain separation performance while reducing energy consumption. The second motor dynamically adjusts speed to match operational requirements.
Solution Approach 2:
The reverse roller speed is dynamically adjusted rather than maintained at constant high speed. The system transitions between different speed levels based on whether sheet separation or energy efficiency is the primary requirement, with the second motor providing dynamic speed control.
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 configuration enhances sheet separation performance and reading efficiency by maintaining the required speed ratios between rollers, preventing unloaded feed and enabling faster processing of multiple sheets while maintaining uniform reading resolution.
Implementation Method 1
The reverse roller is configured to rotate in the rotational direction by torque received from the second motor via a torque limiter
Data Source
AI summary
In an image reading apparatus, in a first process, first and second motor rotate feed and conveyance rollers with circumferential speeds of first and second speeds, respectively. In the first process, the reverse roller has a first separation performance for separating a sheet from another sheet. In a second process, after a detector detects a leading edge of the sheet, the controller stops the first motor, and decelerates the second motor, and the reverse roller has a second separation performance lower than the first separation performance. In a third process, after a trailing edge of the sheet reaches a specific position, the first motor starts rotating the feed roller with the circumferential speed of the first speed. In a fourth process, after the trailing edge of the sheet passes through a reading end position, the controller accelerates the second motor.