Spectral Characteristic Acquisition Apparatus Stable Sheet Positioning

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Solution Overview

Problem

Conventional spectral-characteristic acquisition apparatuses face challenges in maintaining a stable stop position for the recording medium during measurement, especially when the sheet type or thickness varies, leading to misalignment and reduced precision in color data acquisition.

Innovation Solution

The apparatus employs a conveyance system with multiple sheet conveyors and sensors that control the sheet's movement and tension, ensuring stable positioning by stopping the sheet conveyor as soon as the leading end is detected and applying pressure to smooth out wrinkles, while using a transformation matrix to calculate spectral characteristics based on color data from multiple spectral sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional sheet conveyance method is used, then the apparatus structure is simple, but the stop position of the measurable area shifts when sheet type or thickness varies

Engineering Contradiction:
Improvestop position accuracyVSAvoidconveyance control system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements a feedback control mechanism where the position of the measurable area is continuously monitored and the conveyance system automatically adjusts to maintain the correct position. When sheet type or thickness variations occur, the system detects the position shift and compensates by adjusting the conveyance speed or position of the measurable area, ensuring accurate spectral measurement despite material variations.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent employs dynamic adjustment capabilities in the conveyance system, allowing real-time modification of conveyance parameters based on detected sheet properties. The system can dynamically change the speed, position, or tension of the sheet during conveyance to maintain optimal measurement conditions, transforming a static conveyance system into an adaptive one that responds to varying sheet characteristics.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If the sheet conveyor continues rotating during measurement, then the measurement process is continuous, but the sheet cannot be in full contact with the reference plane

Engineering Contradiction:
Improvecontact quality with reference planeVSAvoidmeasurement continuity
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent implements periodic stopping and resuming of the sheet conveyor during the measurement process. The conveyor stops momentarily to allow the sheet to achieve full contact with the reference plane for accurate measurement, then resumes operation. This periodic action ensures high-quality contact during measurement while maintaining overall measurement continuity through rapid stop-start cycles that minimize interruption to the measurement workflow.

Inventive Principle:
Principle #19Periodic 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

This approach allows for precise and stable acquisition of spectral characteristics across different sheet types and thicknesses, reducing misalignment and improving measurement accuracy without damaging the sheet.

Implementation Method 1

measures the colors of an image in a measurable area

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

spectral sensor that receives the light and outputs color data

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 3

The frictional force that acts on the sheet 100 varies depending on the sheet type or the thickness of the sheet 100

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 4

applying pressure to smooth out wrinkles

Methodology Applied
Scientific EffectPressure: Pressure Increase

Data Source

PatentEP4161042B1Spectral-characteristic acquisition apparatus and method of obtaining spectral characteristics
Publication Date: 2025.03.26 RICOH CO LTD
  • EP4161042B1 patent drawingFigure 1
  • EP4161042B1 patent drawingFigure 2~3
  • EP4161042B1 patent drawingFigure 4

AI summary

A spectral-characteristic acquisition apparatus (10) and a method of obtaining spectral characteristics. The spectral-characteristic acquisition apparatus (10) includes a conveyor (30, 31, 32) including a first conveyance roller pair disposed in a conveyance direction in which an object (100) is conveyed and a second conveyance roller pair disposed downstream from the first conveyance roller pair in the conveyance direction, a sensor (42) configured to detect that the object (100) has reached the second conveyance roller pair, a controller (300) configured to control the second conveyance roller pair to drive by a predetermined amount with a driving force greater than a driving force of the first conveyance roller pair upon detecting that the object (100) has reached the second conveyance roller pair by the sensor (42), and to stop driving, a color data obtainer (20) configured to obtain color data from the object (100) at a position where the object (100) stops moving, and a spectral-characteristic computing unit (113) configured to estimate a spectral characteristic of the object (100) based on the color data obtained by the color data obtainer (20).