Application Roller Liquid Feed Control for Uniform Coating
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Solution Overview
Problem
The roller application method for applying liquid to recording media results in uneven application due to the return liquid issue, where the application quantity on a single recording medium changes, leading to thick and thin liquid layers, and requires multiple rollers for different sheet sizes, increasing tool replacement time and complexity.
Innovation Solution
An application apparatus with a medium conveying device, an application roller, a measuring roller, and movement controlling devices that adjust the relative positions of the rollers to prevent return liquid by ensuring the measuring roller abuts the application roller only when the medium is ready, thus preventing liquid feed during non-application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the measuring roller continuously feeds liquid to the application roller, then the application roller is always supplied with liquid, but the liquid accumulates as return liquid causing uneven application thickness
Solution Approach 1:
The measuring roller is controlled to perform periodic contact and separation cycles with the application roller. During the contact phase, liquid is measured and fed to the application roller. During the separation phase, liquid supply is stopped, preventing return liquid accumulation. This periodic action converts continuous supply into controlled intermittent supply, ensuring uniform application thickness while maintaining adequate liquid availability.
2Adaptability or versatility
If multiple application rollers are used for different sheet sizes, then each roller can be optimized for specific sizes, but the device complexity and tool replacement time increase
Solution Approach 1:
The system employs dynamic control of the measuring roller's contact position and timing with the application roller. By adjusting when and how the measuring roller contacts the application roller during the rotation cycle, the system can adapt to different sheet sizes without physical roller changes. This dynamic adjustment mechanism provides versatility for multiple sheet sizes while maintaining a single roller configuration, reducing device complexity.
3Productivity
If the application roller rotates at high speed, then productivity increases, but the liquid application uniformity deteriorates due to centrifugal forces and return liquid
Solution Approach 1:
The harmful return liquid is extracted from the system by controlling the measuring roller to separate from the application roller at appropriate times. This prevents the accumulation and redistribution of return liquid that would otherwise occur at high rotation speeds. By removing the source of unevenness, the system can maintain liquid application uniformity even when operating at higher speeds for increased productivity.
Data Source
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AI summary
An application apparatus includes: a medium conveying device (34) which holds and conveys a medium (14) in a predetermined conveyance direction; an application roller (210) which applies a liquid to the medium (14) held by the medium conveying device (34); an application roller rotating device (30) which rotates the application roller (210) at a predetermined rotational speed; a measuring roller (216) which feeds a predetermined measured amount of the liquid to the application roller (210); a measuring roller rotating device (30) which rotates the measuring roller (216) at a predetermined rotational speed; a first moving device (212) which causes relative movement between the application roller (210) and the medium conveying device (34) to change a distance between the application roller (210) and the medium conveying device (34); a second moving device (218) which causes relative movement between the application roller (210) and the measuring roller (216) to change a distance between the application roller (210) and the measuring roller (216); and a movement controlling device (160) which controls the second moving device (218) in such a manner that, when the application roller (210) and the medium (14) are brought into abutment with each other from a state in which the application roller (210) and the medium (14) are separated from each other, a front end part (14A) of the medium (14) in terms of the conveyance direction abuts with an abutment position on a circumferential surface of the application roller (210) when the application roller (210) and the measuring roller (216) are brought into abutment with each other from a state in which the application roller (210) and the measuring roller (216) are separated from each other.