Image Forming Sheet Feed Position Feedback Control
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Solution Overview
Problem
Existing image forming apparatuses face limitations in shortening the intervals of sheet feed operations due to the need to stop the stepping motor until the next sheet feed timing arrives, which can lead to motor instability and longer cycle times.
Innovation Solution
Implementing a detection and drive control system that detects the sheet position upstream of the feed position and controls the stepping motor to adjust its speed accordingly, allowing the sheet to reach the feed position at the next timing without stopping, thereby stabilizing motor operation and reducing cycle times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stepping motor is stopped until the next sheet feed timing arrives, then the sheet feed timing is accurate, but the interval between sheet feed operations becomes longer and motor stability deteriorates
Solution Approach 1:
The patent applies dynamics by transitioning the stepping motor from a static stop-and-start operation to a continuous dynamic operation. The motor maintains continuous rotation at variable speeds, eliminating idle stop periods while using real-time sheet position detection and adaptive speed control to ensure accurate sheet feed timing. This dynamic approach reduces the sheet feed interval while maintaining motor stability through continuous operation.
Solution Approach 2:
The patent implements feedback control by detecting the actual sheet position during conveyance and using this information to adjust the stepping motor speed in real-time. The sheet position detection unit provides continuous feedback about sheet location, and the control unit modifies motor speed accordingly to ensure the sheet arrives at the feed position at the precise next sheet feed timing, enabling shorter intervals without sacrificing accuracy.
2Loss of time
If the stepping motor runs continuously without stopping, then the sheet feed interval is shortened, but it becomes difficult to control precise sheet feed timing
Solution Approach 1:
The patent uses dynamic speed adjustment of the stepping motor during continuous operation. Instead of running at constant speed, the motor speed is continuously adapted based on real-time sheet position feedback, allowing precise control of sheet arrival timing while maintaining continuous rotation to minimize feed intervals.
Solution Approach 2:
Real-time feedback from the sheet position detection unit enables precise control of sheet feed timing during continuous motor operation. The control unit processes detection timing information and adjusts motor speed dynamically to ensure the sheet reaches the feed position exactly at the next sheet feed timing, achieving high precision without stopping the motor.
3Productivity
If the sheet is detected at an upstream position, then the sheet feed timing can be optimized, but additional detection processing is required
Solution Approach 1:
The patent applies preliminary action by detecting the sheet at an upstream position during its conveyance path, before it reaches the feed position. This early detection allows the control system to calculate and adjust the motor speed in advance, optimizing the timing for the next sheet feed operation and improving overall productivity.
Data Source
AI summary
An image forming apparatus includes a sheet feed portion and a drive control portion. The sheet feed portion includes a conveying member which is provided more on an upstream side of a conveying direction of a sheet than a transfer position of a toner image on a conveying path of the sheet that passes through the transfer position, and feeds the sheet from a sheet feed position that is more on a downstream side of the conveying direction than the conveying member on the conveying path. The drive control portion drives a stepping motor used for driving the conveying member such that the sheet reaches the sheet feed position at a time a next sheet feed timing by the sheet feed portion arrives.