Inkjet Sheet Conveyance Control for Trailing End Positioning
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Solution Overview
Problem
Ink-jet recording apparatuses face challenges in maintaining conveying accuracy and image quality due to the trailing end of sheets stopping in unstable stop areas, leading to reduced throughput and image quality issues.
Innovation Solution
A recording apparatus with a conveyance control unit that adjusts the conveying operation based on the position of the trailing end of the sheet, ensuring it stops within a predetermined range by controlling the conveying roller's drive and the number of nozzles used by the recording head, thereby avoiding unstable stop areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the conveying amount per conveying operation is reduced to avoid unstable stop areas, then the trailing end position stability is improved, but the number of conveying operations increases resulting in reduced throughput
Solution Approach 1:
The system performs preliminary conveying operations to position the trailing end of the sheet in a stable stop area before the main recording operation. By anticipating the sheet position and making advance adjustments, the system ensures stable positioning without requiring excessive conveying operations during the actual recording process, thus maintaining throughput.
Solution Approach 2:
The conveying amount is dynamically adjusted based on the detected position of the trailing end. The system varies the conveying amount between different conveying operations rather than using a fixed small value, allowing the sheet to be positioned accurately in stable areas while minimizing the total number of conveying operations required.
2Productivity
If the conveying amount is increased to improve throughput, then the productivity is improved, but the trailing end stops in unstable stop areas resulting in reduced image quality
Solution Approach 1:
The system uses a trailing end sensor to detect the actual position of the sheet and provides feedback to the control unit. Based on this feedback, the control unit adjusts the conveying amount in subsequent operations to ensure the trailing end is positioned in stable stop areas, thereby maintaining image quality while allowing for efficient throughput.
Solution Approach 2:
The system changes the conveying amount parameter dynamically based on the sheet position feedback. By adjusting this critical parameter, the system can achieve both high throughput and accurate positioning, resolving the contradiction between productivity and manufacturing precision.
3Manufacturing precision
If the number of nozzles used is reduced during trailing end recording, then the conveying accuracy is improved, but the recording time increases resulting in reduced throughput
Solution Approach 1:
The system performs preliminary conveying operations to position the trailing end in stable stop areas before recording begins. This preliminary positioning eliminates the need to reduce nozzle count during recording, as the sheet is already properly positioned, thus maintaining both conveying accuracy and throughput.
Solution Approach 2:
The problem of unstable positioning is extracted and solved separately from the recording process. By handling the positioning issue through preliminary conveying operations and feedback control, the recording process itself can proceed normally with full nozzles engaged, maintaining throughput while ensuring accuracy.
Data Source
AI summary
A recording apparatus for forming images using a recording head includes a feeding roller, a conveying roller, a conveyance control unit, and a recording control unit. The conveyance control unit performs a conveying operation a number of times after the trailing end of a sheet reaches a predetermined position defined between the feeding roller and the conveying roller such that the trailing end of the sheet is disposed in a predetermined range upstream of the conveying roller in a sheet conveying direction after the conveying operations. At least one of the conveying operations performed a number of times is performed based on a distance from the position of the trailing end of the sheet to the position of the conveying roller.