Variable Page Feed Velocity Control for Print Media Ejection Alignment
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Solution Overview
Problem
High-speed printers face challenges in maintaining the alignment and quality of the output stack due to varying print speeds, which results in pages being ejected at high velocities, leading to a lack of control over the gap between sheets, causing misalignment and increased manual alignment time.
Innovation Solution
The implementation of a variable page feed velocity detection system that calculates acceleration and deceleration values for print media in the output zone, allowing for a 'boost' phase to create a larger gap between pages by accelerating the first page and then decelerating it just before ejection, ensuring proper alignment and separation of sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If print media is ejected at high velocity to maintain high print throughput, then productivity is improved, but manufacturing precision deteriorates due to misalignment and poor stack quality
Solution Approach 1:
The system performs preliminary detection of page feed velocity before ejection, calculates required acceleration and deceleration values, and prepares the output zone media movement component accordingly. This preliminary action allows the system to control ejection precision without compromising throughput, as the adjustments are made in advance based on detected velocities.
Solution Approach 2:
The output zone media movement component operates dynamically by adjusting its velocity based on detected page feed velocities. The system accelerates or decelerates the output zone relative to the feed zone to compensate for variations in page ejection speed, maintaining consistent gap control and alignment even at high throughput speeds.
2Productivity
If variable print speeds are used to accommodate different page coverage requirements, then productivity is improved, but manufacturing precision deteriorates due to inconsistent gap control between pages
Solution Approach 1:
The system implements feedback by detecting the actual page feed velocity and using this information to adjust the output zone media movement component's velocity. This closed-loop control ensures that gap control is maintained even when print speeds vary to accommodate different page coverage requirements, resolving the contradiction between productivity and precision.
Solution Approach 2:
The system changes operational parameters by adjusting the output zone media movement component's velocity based on detected page feed velocities. This dynamic parameter adjustment allows the system to maintain consistent gap control across pages with varying coverage requirements while preserving high print throughput.
3Productivity
If high ejection velocity is used to maintain small gaps between pages for high throughput, then productivity is improved, but manufacturing precision deteriorates due to loss of control over page separation
Solution Approach 1:
The system dynamically adjusts the output zone media movement component's velocity to match and control the ejection of pages. By making the output zone velocity variable rather than fixed, the system can maintain small gaps for high throughput while simultaneously controlling page separation and alignment, resolving the contradiction between productivity and precision.
Data Source
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AI summary
According to an example, to eject print media from an image forming apparatus, a variable page feed velocity of a first page of print media exiting a feed zone is detected. An acceleration value and a deceleration value based on the variable page feed velocity of the first page is calculated. The calculated acceleration is applied to a media movement component in the output zone when the entire first page has cleared a media sensor in the front of the output zone, and the deceleration is applied when the tail end of the first page is in a brake zone. In some examples, a second page of print media and a variable page feed velocity of the second page exiting the feed zone is detected, and the media movement component in the output zone is accelerated to match the variable page feed velocity of the second page.