Sheet Curl Correction Mechanism for Inkjet Printers
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Solution Overview
Problem
Existing methods for correcting curl in recording media, particularly the leading end portion, are either complex, increase apparatus size, or restrict curl correction power, leading to inefficiencies in maintaining the proper head-to-paper distance in recording apparatuses like ink jet printers.
Innovation Solution
A method and apparatus that utilize a curl correction mechanism with a decurl roller and pinch roller system, controlled by a unit that adjusts the position and curvature of the leading end portion of the recording medium separately from the rest, allowing for dedicated curl correction without compromising sheet conveying performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a special mechanism unit is added to correct curl in the leading end portion, then curl correction effectiveness is improved, but device complexity and size increase
Solution Approach 1:
The patent divides the sheet into two regions: the leading end portion and the remaining portion. Different curl correction strategies are applied to each region - the leading end portion receives dedicated curl correction treatment while the remaining portion uses conventional correction methods. This segmentation allows effective curl correction without requiring a completely separate special mechanism for the entire sheet.
Solution Approach 2:
The patent applies different curl correction properties to different parts of the sheet. The leading end portion is subjected to specific curl correction measures (such as applying force at specific locations or using specific roller configurations) that differ from the treatment applied to the remaining portion. This local quality approach ensures that the leading end portion, which has different curl characteristics, receives appropriate correction without over-complicating the entire system.
2Manufacturing precision
If the leading end portion is strongly curved to correct curl, then curl correction power is improved, but sheet conveying performance deteriorates
Solution Approach 1:
The patent employs dynamic control of the curl correction mechanism, allowing the curvature applied to the leading end portion to be adjusted based on real-time conditions. The system can vary the degree of curving, the position of applying force, and the duration of correction to achieve effective curl correction while maintaining the sheet's conveyability. This dynamic approach prevents excessive curving that would harm conveying performance.
Solution Approach 2:
The patent changes key parameters of the curl correction process, such as the position where force is applied, the magnitude of curving force, and the timing of correction, to optimize both curl correction effectiveness and sheet conveying performance. By adjusting these parameters, the system achieves strong enough curl correction power while avoiding excessive deformation that would compromise conveying reliability.
3Manufacturing precision
If the entire recording medium is curled downward, then head-to-paper distance management is improved, but recording surface contact with recording head increases
Solution Approach 1:
The patent applies different curving directions to different portions of the recording medium. The leading end portion is curled downward to prevent contact with the recording head and maintain proper head-to-paper distance, while the remaining portion is curled upward to prevent the recording surface from convexing toward the recording head. This local quality approach resolves the contradiction by applying opposite curving directions to different regions.
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
In a first step, a sheet (1) is conveyed in a direction for making recording, thereby feeding a leading end portion of the sheet to a position between a decurl roller (9) and a decurl pinch roller (11), which are in positions spaced apart from each other. In a second step, the leading end portion of the sheet is curved and held by causing the decurl pinch roller to come close to or press against the decurl roller. In a third step, the leading end portion of the sheet is withdrawn from between the decurl roller and the decurl pinch roller by conveying the sheet in a direction opposed to the conveying direction. After executing the first to third steps, the sheet is conveyed in the conveying direction through the first step while the sheet is curved by the decurl roller.