Switchable Discharge Unit for Scratch-Free Sheet Conveyance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Large format inkjet printers face issues with sheet conveyance accuracy and scratches when handling sheets of different lengths due to varying numbers of roller pairs and discharge path configurations, leading to inefficiencies in conveyance mechanisms.
Innovation Solution
A printing apparatus with a switchable discharge unit that can alternate between a nip state and a nip released state, allowing for adjustable conveyance force based on sheet length, and a path switching mechanism to select between different discharge paths, ensuring accurate and scratch-free conveyance of sheets of varying lengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of roller pairs is increased to improve conveyance accuracy for short sheets, then conveyance accuracy improves, but the risk of scratches increases due to multiple nipping points
Solution Approach 1:
The separation distance between roller pairs is made dynamically adjustable based on sheet length. For short sheets, rollers are positioned closer together or some are deactivated, reducing the number of simultaneous nipping points and preventing scratches. For long sheets, rollers are positioned farther apart or all are activated, ensuring adequate conveyance accuracy throughout the sheet length.
Solution Approach 2:
Different roller pairs are configured with different separation distances appropriate for different sheet lengths. The system applies localized adjustment to specific roller pairs rather than uniformly configuring all rollers, allowing optimal conveyance for each sheet length while minimizing scratches by reducing active nipping points for short sheets.
2Object-affected harmful factors
If the separation between roller pairs is increased to reduce scratches on short sheets, then scratch prevention improves, but conveyance accuracy decreases for long sheets
Solution Approach 1:
The roller pair separation is dynamically adjusted based on detected sheet length. When a short sheet is detected, the separation is increased or certain roller pairs are deactivated to prevent scratches. When a long sheet is detected, the separation is optimized to maintain conveyance accuracy throughout the extended sheet length, ensuring all rollers remain engaged appropriately.
Solution Approach 2:
The system changes the separation parameter between roller pairs based on sheet length classification. For short sheets, larger separation or reduced active roller pairs prevents scratches. For long sheets, optimized separation maintains conveyance accuracy. This parameter adaptation resolves the contradiction between scratch prevention and conveyance precision.
3Adaptability or versatility
If multiple discharge paths with different path lengths are provided to handle various sheet lengths, then adaptability improves, but device complexity increases due to additional switching mechanisms
Solution Approach 1:
Multiple discharge paths are configured with different lengths to serve different sheet length requirements. Each path is optimized for specific sheet length ranges, providing universal handling capability. The switching mechanism selects the appropriate path based on sheet length, making the system versatile while managing complexity through intelligent routing decisions.
Solution Approach 2:
The discharge system is segmented into multiple independent paths with different characteristics. Each path can be independently controlled and optimized for specific sheet lengths. This segmentation allows the system to handle various sheet lengths effectively while the switching mechanism manages complexity by routing sheets through the most appropriate path based on detected length.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A printing apparatus (1) includes: printing means (4); first conveyance means (3) arranged to convey a sheet to the printing means; second conveyance means (7) provided on a downstream side of the first conveyance means in a conveyance direction of the sheet, and arranged to convey the sheet with nipping the sheet; third conveyance means (8) provided on a downstream side of the second conveyance means in the conveyance direction, and arranged to convey the sheet; and switching means (DU1) arranged to switch a nip state of the second conveyance means and a released state in which the nip state is released. When the sheet is conveyed by the third conveyance means, the switching means switches the nip state and the released state in accordance with a length of the sheet.