Sheet Conveyance Control for Edge Print Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional printing techniques experience a decline in print quality near the edges of sheets due to distortion and positional deviations, leading to ink smudges and reduced precision during the transition from double-held to single-held states in sheet conveyance.
Innovation Solution
A printing device with a conveying mechanism and control system that includes a print head, rollers, and a supporting unit, which executes specific conveyance processes to maintain sheet stability and precision by adjusting the conveyance amounts and support states, ensuring consistent ink deposition and edge alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the sheet is conveyed using only one pair of rollers during edge printing, then the conveyance mechanism is simplified, but the sheet stability deteriorates causing edge movement and distortion
Solution Approach 1:
The conveying mechanism is segmented into multiple roller pairs positioned at different locations (upstream, center, downstream) relative to the print head. This segmentation allows different roller pairs to be activated selectively based on the printing location, providing stable sheet support during edge printing while maintaining mechanism simplicity through modular operation
Solution Approach 2:
A third roller pair is introduced as an intermediary support element between the upstream and downstream roller pairs. This intermediary roller provides additional support during edge printing operations, preventing sheet distortion and movement without requiring complete redesign of the entire conveying system
2Productivity
If the conveyance amount is increased during single-held state, then the printing speed is improved, but the sheet distortion increases causing positional deviation
Solution Approach 1:
The conveyance amount is dynamically adjusted based on the printing location and sheet holding state. During single-held state at sheet edges, a smaller conveyance amount is used to prevent distortion. During double-held state at sheet center, a larger conveyance amount is used to maximize printing speed. This dynamic adjustment resolves the contradiction between speed and precision
3Stability of the object's composition
If the sheet is held by both roller pairs during edge printing, then the sheet stability is improved, but the conveyance control complexity increases
Solution Approach 1:
The conveying system operates in periodic cycles, alternating between different roller pair configurations based on print head position. During certain phases, upstream and downstream rollers are both active; during other phases, only one pair is active. This periodic switching provides stable sheet support when needed while keeping control complexity manageable through systematic operation patterns
Data Source
AI summary
A printing device executes processes (a)-(c). In the process (a), first and second rollers convey a sheet a first amount, and a print head executes a printing operation while the sheet is in a state where the sheet is supported by the first and second rollers and a supporting unit disposed between the first and second rollers. In the process (b), the second roller conveys the sheet a second amount that is no larger than the first amount, and the print head executes a printing operation while the sheet is in a state where the sheet is supported by the supporting unit and the second roller. In the process (c), the second roller conveys the sheet a third amount that is larger than the first amount, and the print head executes a printing operation while the sheet is in a state where the sheet is supported by the second roller.