Image Forming Apparatus Roller Speed Control
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Solution Overview
Problem
Existing image forming apparatuses face challenges in dynamically adjusting the rotation speed of rollers for sheet conveyance, requiring additional drive trains and clutches, which complicates conveyance control and makes handling issues like paper jams difficult.
Innovation Solution
The apparatus includes a motor driving both the paper feed roller and conveying roller, with encoders to detect rotation and sensors to control the motor based on the sheet's position, allowing for dynamic adjustment of rotation speed through a control unit using PID control and electromagnetic clutches to manage power transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed gear ratio is used to drive the roller from another roller's motor, then the device complexity is reduced, but the adaptability of rotation speed adjustment is worsened
Solution Approach 1:
The patent applies dynamics by making the transmission ratio variable instead of fixed. The transmission mechanism includes a movable component that can change the gear ratio dynamically, allowing the driven roller's rotation speed to be adjusted independently while maintaining a simple overall drive train structure. This resolves the contradiction by enabling adaptability without significantly increasing device complexity.
2Adaptability or versatility
If another drive train and electromagnetic clutch are added to change roller rotation speed, then the adaptability of rotation speed adjustment is improved, but the device complexity is worsened
Solution Approach 1:
The patent merges the speed adjustment function into the existing drive train by integrating a variable transmission mechanism directly into the roller drive system. Instead of adding a separate drive train and electromagnetic clutch, the invention combines speed variation capability within the current mechanical linkage, thereby improving adaptability while minimizing the increase in device complexity.
3Ease of operation
If the roller is driven by another roller's motor with fixed gear ratio, then the conveyance control becomes simpler, but the ability to handle conveyance failures is worsened
Solution Approach 1:
The variable transmission mechanism allows the system to dynamically adjust the driven roller's rotation speed independently of the driving roller. This enables the control system to respond to conveyance failures by adjusting speed ratios, improving reliability while maintaining relatively simple conveyance control through the unified drive train architecture.
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 enables high-accuracy sheet conveyance by adjusting the rotation speed of rollers based on actual measured values, simplifying control and reducing the need for complex motor designs, thus improving conveyance accuracy and reducing costs.
Implementation Method 1
A first clutch is provided to switch between connecting and disconnecting the paper feed roller to the motor. A second clutch is provided to switch between connecting and disconnecting the motor to the conveying roller.
Data Source
AI summary
An image forming apparatus includes a sheet accommodation unit, a feed roller to feed a sheet along a conveyance path, a first encoder to detect rotation of the feed roller, a conveying roller downstream of the feed roller, a second encoder to detect rotation of the conveying roller, and a motor to drive the feed roller and the conveying roller. A first clutch switches between connecting and disconnecting the paper feed roller to the motor. A second clutch switches between connecting and disconnecting the motor to the conveying roller. A first sensor detects the sheet at a first position. A second sensor detects the sheet at a second position. A control unit controls the motor based on output from the first encoder when the sheet is at the first position and output from the second encoder when the sheet is at the second position.