Stepping Motor Control for Jam Ejection in Sheet Conveyance
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Solution Overview
Problem
In tandem image forming systems, rapid load application to stepping motors during sheet ejection at jamming can cause out-of-step issues, compromising the efficiency of sheet removal and motor performance.
Innovation Solution
A sheet conveying device with multiple conveying roller pairs and a movable guide portion, where the downstream-side conveying roller pair is stopped, and the upstream-side pair continuously rotates, with the control portion ensuring a higher conveying force for the stepping motor driving the upstream-side roller pair, preventing rapid load-induced out-of-step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the downstream-side conveying roller is stopped immediately at jamming to eject sheets efficiently, then sheet ejection efficiency is improved, but a rapid load is applied to the upstream-side conveying motor causing out-of-step
Solution Approach 1:
The control unit increases the conveying force of the upstream-side conveying motor in advance before the rapid load occurs. By detecting the jamming state and proactively boosting the motor output, the system prevents out-of-step without waiting for the load shock to manifest, thus maintaining both efficient sheet ejection and motor synchronization
Solution Approach 2:
The control unit prepares a higher conveying force state for the upstream-side conveying motor before the rapid load application. This preemptive cushioning of motor capability ensures that when the downstream roller stops and the sheet exerts backward force, the motor already has the reserves to handle the shock without losing step
2Productivity
If the upstream-side conveying roller continuously rotates at high speed to maintain conveying force, then sheet ejection capability is maintained, but energy consumption increases
Solution Approach 1:
The control unit operates the upstream-side conveying motor in a periodic manner: during normal operation it rotates continuously to maintain conveying capability, but during jamming handling it maintains high speed only temporarily while the downstream roller is stopped. After sheet ejection, the motor speed is reduced. This periodic high-speed operation balances sheet conveying capability with energy consumption
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 efficient sheet ejection without causing stepping motor out-of-step, improving jam handling and motor reliability in tandem image forming systems.
Implementation Method 1
a force in a direction opposite to a conveying direction of the sheet is applied by the sheet to the upstream-side conveying roller
Implementation Method 2
The movable guide portion opens the sheet conveying path by moving one of rollers of at least the downstream-side conveying roller pair in the plurality of conveying roller pairs in a direction away from the sheet conveying path
Implementation Method 3
a conveying force for conveying a sheet of a stepping motor driving the upstream-side conveying roller pair is larger than the conveying force before the downstream-side conveying roller pair is stopped
Data Source
AI summary
At occurrence of jamming, a downstream-side conveying roller pair is stopped, while an upstream-side conveying roller pair continuously rotates, whereby a sheet between the downstream-side conveying roller pair and the upstream-side conveying roller pair is ejected from a sheet conveying path opened by a movable guide portion. At this time, a conveying force of a stepping motor driving the upstream-side conveying roller pair is made larger than the conveying force before the occurrence of jamming.