Reaction Force Observer for Sheet Transport Positioning
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Solution Overview
Problem
Conventional image forming systems face inaccuracies in positioning sheets at target locations due to errors between roller rotation counts and actual paper transport, especially caused by paper slip and indirect measurement methods.
Innovation Solution
An image forming system with a first and second motor, roller, and a controller that includes a motor control unit and a reaction-force estimating observer, where the controller controls the second roller's rotation based on estimated reaction forces to accurately position sheets downstream of the nip position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the paper transport amount is indirectly measured by the position count operation of the paper feed roller, then the sheet can be supplied to the transport roller, but the measurement precision deteriorates due to errors between count value and actual transport amount
Solution Approach 1:
The patent replaces the mechanical position count measurement method with a reaction force detection method. A reaction force detection unit directly measures the reaction force generated when the paper is nipped by the transport roller, substituting the indirect mechanical counting system with a direct force-based measurement system that accurately reflects actual paper transport.
Solution Approach 2:
The patent introduces a reaction force detection unit as an intermediary between the paper transport process and the control system. This intermediary directly senses the physical interaction (reaction force) at the nip point, providing accurate real-time feedback about paper transport status without relying on indirect roller position counting.
2Ease of operation
If the transport roller is stopped or reversely rotated to position the front end of paper at the nip position, then paper cueing can be performed, but the device complexity increases due to multiple rotation control modes
Solution Approach 1:
The patent employs feedback control by continuously detecting the reaction force during paper transport. The control unit monitors the reaction force signal and automatically adjusts the transport roller rotation to maintain optimal paper positioning, eliminating the need for complex manual control of multiple rotation modes while improving cueing accuracy.
Solution Approach 2:
The system performs self-adjustment through automatic reaction force-based control. The transport roller automatically positions the paper at the target location by responding to the reaction force feedback, without requiring complex external control interventions or manual switching between different rotation modes.
Data Source
AI summary
A sheet transport apparatus includes: a first motor and a second motor; a first roller configured to: rotate upon receiving motive power from the first motor; and transport a sheet in a predetermined transport direction; a second roller which is provided on a downstream side of the first roller in the transport direction and which is configured to: rotate upon receiving motive power from the second motor while nipping the sheet transported by the first roller at a nip position; and transport the sheet further downstream in the transport direction; and a controller. The controller includes a motor control unit configured to perform a first process for rotating the first roller and a second process for rotating the second roller; and a first reaction-force estimating observer configured to calculate a first estimated value which is an estimated value of a reaction force acting on the first motor.