Image Forming Apparatus Transport Speed Control for Timing Precision
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Solution Overview
Problem
Existing image forming apparatuses face challenges in precisely timing the transport of media to a transfer portion due to a single speed-change control point, leading to variations in transport speed and timing.
Innovation Solution
An image forming apparatus is designed with a positioning portion upstream of the transfer portion, a detector downstream, and a controller that adjusts the transport speed based on the elapsed time since transport started, ensuring precise timing and minimizing speed differences between the medium and the driving source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single speed-change control point is used in the sheet transport path, then the device complexity is reduced, but the manufacturing precision of sheet transport timing deteriorates
Solution Approach 1:
The transport path is divided into multiple sections with different speed control characteristics. A first speed control section operates upstream of the transfer position while a second speed control section operates downstream, allowing independent optimization of timing precision in different zones without requiring complete redesign of the entire transport system.
Solution Approach 2:
The first speed control section performs preliminary speed adjustment upstream of the transfer position, preparing the sheet for precise positioning before it reaches the critical transfer zone. This preliminary action allows the second speed control section to focus on fine-tuning the timing, improving overall precision without proportionally increasing complexity.
2Ease of operation
If the transport speed is changed at a single control point, then the ease of operation is improved, but the reliability of image transfer deteriorates due to speed variations
Solution Approach 1:
The system dynamically adjusts transport speed at two different control points rather than using a static single-point control. The first dynamic speed control section adjusts speed upstream while the second dynamic speed control section adjusts speed downstream, allowing the system to adapt to varying sheet conditions and maintain reliable image transfer.
Solution Approach 2:
The controller monitors sheet transport timing and speed at multiple points, using feedback from sheet position detection to adjust speeds in both control sections. This feedback mechanism ensures that speed variations are corrected in real-time, maintaining reliable image transfer while keeping operation straightforward through automated control.
3Device complexity
If a single speed control point is used from transport start to transfer portion, then the device complexity is reduced, but the precision of transport timing to transfer portion deteriorates
Solution Approach 1:
The control system is segmented into two independent speed control sections: a first speed control section for the upstream portion and a second speed control section for the downstream portion. This segmentation allows each section to be optimized for its specific function, improving timing precision at the transfer portion without requiring a completely complex unified control system.
Solution Approach 2:
The first speed control section performs preliminary timing adjustment during the upstream transport phase, establishing a foundation for precise transfer timing. The second speed control section then refines this timing as the sheet approaches the transfer portion, achieving high precision through staged control actions rather than a single complex control point.
Data Source
AI summary
Provided is an image forming apparatus including a positioning portion provided upstream of a transfer portion in a transport direction of a recording medium. The positioning portion positions the medium using a leading end of the medium. Additionally included is a detector that is disposed downstream of the positioning portion in the transport direction, and that detects passage of the leading end of the medium; and a controller that controls a transport speed in a period from when the leading end of the medium passes through the detector to when the leading end of the medium passes through a target position situated downstream of the detector in the transport direction, in accordance with a time since transport of the medium is started from the positioning portion until the leading end of the medium passes through the detector.