Coating Roller Power-Off Drain Sequence for Uniform Sheet Coating

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Solution Overview

Problem

Existing coating devices suffer from the issue of coating liquid adhering to the coating roller when the device is turned off, leading to variations in the amount of coating applied and deterioration of image quality on sheets.

Innovation Solution

A coating device with a reservoir, coating roller, pressure roller, separator, supply unit, drain unit, and liquid level detector, controlled by circuitry to manage the power-off process, ensuring the pressure roller contacts the coating roller for idle rotation to remove residual coating liquid.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the coating device is turned off and the coating liquid drain unit drains the coating liquid from the reservoir, then the coating liquid in the reservoir is removed, but the coating liquid adhering to the coating roller becomes fixed onto the coating roller

Engineering Contradiction:
Improvecoating liquid in reservoirVSAvoidcoating liquid application consistency
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent applies preliminary action by performing idle rotation of the coating roller and pressure roller before the coating liquid becomes completely fixed on the coating roller. The controller rotates the coating roller and pressure roller for a predetermined time after power-off detection, which removes residual coating liquid from the coating roller surface before it can adhere firmly, thereby preventing coating quality deterioration in subsequent operations

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent maintains continuity of useful action by keeping the coating roller and pressure roller in contact during idle rotation. The separator maintains contact between the rollers while the controller rotates them, ensuring continuous mechanical action to remove residual coating liquid. This continuous contact and rotation prevents the coating liquid from settling and fixing on the roller surface

Inventive Principle:
Principle #20Continuity of useful action

2Ease of operation

If the pressure roller is separated from the coating roller, then the coating roller can rotate freely, but the coating liquid adhering to the coating roller remains fixed and causes variation in coating amount

Engineering Contradiction:
Improvecoating roller rotation freedomVSAvoidcoating liquid application uniformity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent performs preliminary action by executing idle rotation with the pressure roller and coating roller in contact before separation. This preliminary contact rotation removes residual coating liquid from the coating roller surface, ensuring that when the rollers are subsequently separated, the coating roller does not have fixed coating liquid that would cause variation in subsequent coating applications

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent maintains continuity of useful action by keeping the pressure roller and coating roller in contact during the idle rotation phase. This continuous contact enables effective mechanical removal of residual coating liquid through rotation, whereas separation would allow the coating liquid to remain fixed on the coating roller surface

Inventive Principle:
Principle #20Continuity of useful action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Prevents coating liquid from being fixed on the coating roller, maintaining consistent application and image quality by reducing variations in coating liquid amount and ensuring even distribution.

Implementation Method 1

a pressure roller to contact the coating roller to form a nip between the coating roller and the pressure roller to nip and convey the sheet

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the pressure roller into contact with the coating roller to form the nip after a detection of the liquid level below the non-supply position

Methodology Applied
Scientific EffectPressure: Pressure Increase

Data Source

PatentEP4670991A1Coating device and image forming system
Publication Date: 2025.12.31 RICOH CO LTD
  • EP4670991A1 patent drawingFigure 1
  • EP4670991A1 patent drawingFigure 2~3
  • EP4670991A1 patent drawingFigure 4~5B

AI summary

A coating device (50) includes a reservoir (57) to store a coating liquid, a coating roller (52) to coat a sheet, a pressure roller (66) to contact the coating roller (52), a separator (71) to bring and separate the pressure roller (66) into contact with and from the coating roller (52), a supply unit to supply the coating liquid, a drain unit to drain the coating liquid, a liquid level detector (58) to detect that a liquid level is below a non-supply position, and circuitry (70) to control the drain unit to drain the coating liquid after a power-off of the coating device (50), control the separator (71) to bring the pressure roller (66) into contact with the coating roller (52) after a detection of the liquid level below the non-supply position, and rotate the pressure roller (66) and the coating roller (52) for a predetermined time.