Liquid Discharge Apparatus Encoder Timing Control

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Solution Overview

Problem

Existing liquid discharge apparatuses face challenges in accurately controlling the discharge timing of liquid onto a sheet material being conveyed on a rotator, particularly due to inaccuracies in rotation and movement tracking, which affect printing quality and precision.

Innovation Solution

A liquid discharge apparatus that incorporates a rotator, a liquid discharger, a sheet-material position detector, and encoders to determine and generate precise discharge timing signals based on the rotation and movement of the sheet material, ensuring accurate liquid application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a rotary encoder is used to detect rotation amount of the rotator, then the discharge timing can be controlled, but detection inaccuracies occur due to rotation fluctuations affecting printing precision

Engineering Contradiction:

Improvedischarge timing accuracyVSAvoiddetection accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

A scale is attached to the circumferential surface of the rotator as an intermediary element. Instead of directly detecting rotator rotation, the linear encoder detects the position of this scale, which moves linearly with the rotator's rotation. This intermediary scale converts rotational motion into linear position detection, allowing accurate tracking of sheet material position without being affected by rotator rotation fluctuations.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the rotary encoder (mechanical rotation detection) with a linear encoder (linear position detection). By attaching a scale to the rotator's circumferential surface and using a linear encoder to read its position, the system substitutes a mechanical rotation detection mechanism with a linear position measurement system, eliminating the impact of rotational instability on detection accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If only a rotary encoder is used for discharge timing control, then the system is simple, but printing precision deteriorates due to accumulation of detection errors

Engineering Contradiction:

Improveencoder system complexityVSAvoidprinting precision

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent merges two detection approaches: a rotary encoder for determining discharge start timing and a linear encoder for generating discharge timing during liquid discharge. This combination allows the system to use the rotary encoder's simplicity for initial timing while leveraging the linear encoder's accuracy for maintaining precision throughout the discharge process, achieving both simplicity and high precision.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The discharge timing control is segmented into two phases: discharge start timing determination using the rotary encoder, and discharge timing generation during the actual discharge process using the linear encoder. This segmentation allows each encoder to be used for the phase where it performs best, reducing overall error accumulation while maintaining system simplicity.

Inventive Principle:

Principle #1Segmentation

3Ease of operation

If the discharge timing is determined only from rotary encoder signals, then the control system is simple, but errors accumulate affecting liquid discharge accuracy

Engineering Contradiction:

Improvecontrol system simplicityVSAvoidliquid discharge accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The scale attached to the rotator serves as an intermediary that enables the linear encoder to accurately track the position of the sheet material on the rotator's circumferential surface. This intermediary mechanism allows the system to maintain simplicity while achieving high discharge accuracy by using linear position detection instead of direct rotational detection.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent substitutes direct rotational detection (prone to error accumulation) with linear position detection along the circumferential surface. By reading the position of the scale attached to the rotator with a linear encoder, the system replaces a mechanically complex and error-prone rotational measurement system with a more accurate linear measurement approach.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS10792912B2Liquid discharge apparatus

Publication Date: 2020.10.06 RICOH CO LTD

AI summary

A liquid discharge apparatus includes a rotator, a liquid discharger, a sheet-material position detector, a first signal output device, a second signal output device, and circuitry. The rotator carries a sheet material on a circumferential surface and conveys the sheet material. The liquid discharger discharges liquid onto the sheet material. The sheet-material position detector detects a position of the sheet material. The first signal output device outputs a first signal corresponding to a rotation amount of the rotator. The second signal output device outputs a second signal correlated with a movement amount of the sheet material on the circumferential surface of the rotator. The circuitry determines a discharge start timing of the liquid discharger from a detection result of the sheet-material position detector and the first signal, and generates a discharge timing of the liquid discharger from the second signal.