Printer Discharge Head Recess Geometry for Droplet Bending Control

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Solution Overview

Problem

Existing discharge heads in printers experience issues with droplet bending and white streaks due to varying airflow resistance at the ends of nozzle rows, leading to abnormal image formation.

Innovation Solution

Incorporation of recesses with varying wall face heights and orientations to stabilize airflow and reduce airflow resistance differences across nozzle rows, using recesses to guide airflow in a manner that minimizes droplet bending.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple nozzles are arrayed in a nozzle row to increase discharge capacity, then productivity is improved, but droplet bending and white streaks occur due to varying airflow resistance at the ends of nozzle rows

Engineering Contradiction:

Improvedischarge capacityVSAvoidimage quality

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies local quality by creating a recess structure specifically at the end portion of the nozzle row where airflow resistance is highest. The recess has a depth that varies along the nozzle row direction, being deeper at the end portion and shallower toward the center, thereby locally adjusting the airflow characteristics only where needed to prevent droplet bending without affecting the overall discharge capacity of the nozzle array.

Inventive Principle:

Principle #3Local quality

2Area of stationary object

If the nozzle row extends in the first direction to cover a wider area, then the area of stationary object is improved, but airflow resistance varies across the nozzle row causing droplet landing inconsistency

Engineering Contradiction:

Improvecoverage areaVSAvoiddroplet landing consistency

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The recess structure is designed with varying depth along the first direction (nozzle row direction), creating different local airflow conditions at different positions. The end portion has a greater recess depth to compensate for higher airflow resistance, while the center portion has a shallower depth, thereby maintaining consistent droplet landing across the entire extended nozzle row coverage area.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces a third dimension (depth direction) by creating a recess below the nozzle row plane. This dimensional addition allows control of airflow characteristics without changing the horizontal arrangement of nozzles, thereby maintaining coverage area while improving droplet landing consistency through vertical airflow modification.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Reliability

If a recess is added to stabilize airflow and reduce airflow resistance differences, then droplet bending is prevented, but device complexity increases

Engineering Contradiction:

Improveairflow stabilityVSAvoiddischarge head structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The recess structure is integrated into the discharge head body as a unified component rather than being added as a separate attachment. The varying-depth recess is formed as part of the discharge head's internal structure, merging the airflow control function with the existing nozzle support structure, thereby reducing overall device complexity while achieving airflow stabilization.

Inventive Principle:

Principle #5Merging (Combining)

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 droplet bending and improves image quality by stabilizing airflow, reducing white streaks and ensuring consistent droplet landing.

Implementation Method 1

Methodology Applied

Scientific EffectAirflow guidance:

Data Source

PatentUS12552165B2Discharge head, discharge head unit, discharge apparatus, and printer

Publication Date: 2026.02.17 RICOH CO LTD

AI summary

A discharge head includes multiple nozzles and a recess. The multiple nozzles are arrayed in a first direction. A liquid is dischargeable from the multiple nozzles in a discharge direction. The recess is recessed from the nozzle face in a second direction, is disposed at one side of a nozzle row in a third direction, and has a wall face extending in the first direction and the second direction. The wall face is disposed between the nozzle row and a side face of the discharge head. The discharge head has an inner region in which the multiple nozzles are arrayed and an outer region outside the inner region in the first direction. The recess covers a boundary region between the inner region and the outer region. The wall face has a first height in the outer region and a second height lower than the first height in the inner region.