Overlapping Sheet Conveyance for Duplex Printing Speed
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Solution Overview
Problem
Conventional printing apparatuses experience reduced printing speed when performing two-sided printing, as they do not efficiently manage the conveyance of sheets to maintain continuous and overlapping overlap of trailing and leading edges during the printing process.
Innovation Solution
A printing apparatus with a control method that coordinates the conveyance of sheets to ensure the trailing edge of one sheet overlaps with the leading edge of the next, utilizing a control unit to manage the feeding, conveying, and inversion mechanisms to optimize sheet alignment and movement, allowing for simultaneous printing on both sides while maintaining a predetermined overlap for increased speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If successive overlapped conveyance is used to improve printing speed, then printing speed is improved, but coordination complexity between feeding, conveying, and inversion mechanisms increases
Solution Approach 1:
The control unit starts conveyance of the succeeding sheet in advance before the preceding sheet has finished printing. By predicting when the trailing edge will reach the conveyance position and calculating the appropriate timing, the system prepares the next sheet's position beforehand, enabling seamless overlapping conveyance without waiting for complete printing cycles.
Solution Approach 2:
The control unit continuously monitors the position of sheets during conveyance and dynamically adjusts the timing and speed of feeding and conveying mechanisms. By tracking the actual position of trailing edges and leading edges in real-time, the system optimizes the overlap coordination to maintain precise alignment while maximizing printing speed.
2Productivity
If sheets are conveyed continuously with narrow gaps to improve speed, then printing speed is improved, but alignment precision between sheets deteriorates
Solution Approach 1:
The system performs preliminary positioning of the succeeding sheet by conveying it to a predetermined position where the leading edge is aligned with the trailing edge of the preceding sheet before printing begins. This advance positioning ensures that even with continuous conveyance and narrow gaps, the sheets maintain proper alignment throughout the printing process.
Solution Approach 2:
The control unit replaces manual or simple mechanical alignment methods with automated computational control. By calculating the exact conveyance distances and timings based on sheet size, printing speed, and overlap requirements, the system achieves precise alignment automatically, eliminating the need for physical alignment mechanisms or manual intervention.
3Productivity
If the succeeding sheet is fed before the preceding sheet printing ends to improve speed, then printing speed is improved, but sheet overlap control becomes more difficult
Solution Approach 1:
The control unit implements continuous feedback monitoring of sheet positions during the overlapping conveyance process. By detecting the actual positions of both the preceding and succeeding sheets in real-time, the system dynamically adjusts conveyance speed and timing to maintain the desired overlap, making the control process easier despite the complexity of feeding sheets before printing completes.
Solution Approach 2:
The control unit acts as an intermediary that coordinates between the feeding mechanism, conveying mechanism, and inversion mechanism. It translates the requirement for overlapping conveyance into specific control signals for each subsystem, managing the timing and speed adjustments needed to maintain proper sheet overlap while enabling faster printing.
Data Source
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AI summary
A printing apparatus includes: feeding means (3,4) feeding a sheet; conveying means (5,6) conveying the sheet fed by the feeding means; printing means (7) printing the sheet conveyed by the conveying means; an inversion path inverting the sheet printed on a first surface by the printing means and conveying the sheet to the conveying means; and conveyance control means performing conveyance control of overlapping a trailing edge of a preceding sheet conveyed through the inversion path and a leading edge of a succeeding sheet fed following the preceding sheet.