Drive Controller Stabilizes Liquid Discharge via Dynamic Pulse Timing

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Solution Overview

Problem

Existing liquid discharge systems face variations in discharge state and image quality due to differences in discharge conditions such as droplet size and external factors like temperature, leading to instability in liquid discharge from the liquid discharge head.

Innovation Solution

A drive controller generates specific drive pulses with varying displacement amounts and holding times to stabilize the discharge, including a first drive pulse with a longer holding time and a second drive pulse with a shorter holding time but larger displacement average, and multiple drive pulses for different droplet sizes and frequencies to maintain consistent discharge velocity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single drive pulse with fixed holding time is used, then the discharge process is simple, but the discharge state varies due to differences in droplet size and external conditions

Engineering Contradiction:

Improvedischarge state stabilityVSAvoiddrive pulse control complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The drive controller dynamically selects between a first drive pulse with a longer holding time and a second drive pulse with a shorter holding time based on the discharge conditions. This dynamic adaptation allows the system to maintain stable discharge state across varying droplet sizes and external conditions without requiring a fundamentally more complex hardware architecture.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the holding time parameter of the drive pulse based on discharge conditions. By adjusting this temporal parameter, the system optimizes the discharge state for different droplet sizes and environmental conditions, resolving the contradiction between maintaining simple control and achieving reliable discharge.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If the holding time is extended to ensure complete discharge, then smaller droplets are properly discharged, but larger droplets overshoot and cause liquid to remain outside the discharge port

Engineering Contradiction:

Improvedischarge position accuracyVSAvoiddischarge cycle efficiency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The system applies different holding times tailored to specific discharge conditions - a longer holding time for smaller droplets requiring complete discharge, and a shorter holding time for larger droplets that move faster. This localized optimization of the holding time parameter ensures each droplet type achieves accurate positioning without overshooting, while maintaining overall discharge cycle efficiency.

Inventive Principle:

Principle #3Local quality

3Speed

If the holding time is shortened to improve discharge speed, then larger droplets are discharged quickly, but smaller droplets do not complete their discharge and remain in the discharge port

Engineering Contradiction:

Improvedischarge velocityVSAvoidcomplete discharge reliability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The drive controller dynamically adjusts the holding time based on droplet size and discharge conditions. For smaller droplets that require more time to complete discharge, a longer holding time is applied to ensure complete ejection. For larger droplets that discharge faster, a shorter holding time prevents overshooting. This dynamic parameter adjustment resolves the contradiction between discharge speed and complete discharge reliability.

Inventive Principle:

Principle #15Dynamics

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

The drive controller stabilizes the discharge state and improves image quality by ensuring consistent discharge velocity and amount regardless of droplet size, effectively addressing variations in discharge conditions.

Implementation Method 1

a voltage is applied to a piezoelectric element to expand and contract the piezoelectric element, and thus a movable body is moved to open and close a discharge port

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS20250091342A1Drive controller, head device, and liquid discharge apparatus

Publication Date: 2025.03.20 RICOH CO LTD

AI summary

A drive controller includes: circuitry configured to: drive a liquid discharge head, including a discharge port and a valve to open and close the discharge port, to discharge a liquid from the discharge port, generate a drive pulse to drive the valve to open and close the discharge port; and the drive pulse including: a first drive pulse to hold the valve at a first displacement amount for a first holding time; and a second drive pulse to hold the valve at a second displacement amount for a second holding time, wherein the second holding time is shorter than the first holding time, and a second average value of the second displace amount is larger than a first average value of the first displace amount.