Parallel Flushing and Printing in Inkjet Print Heads

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Solution Overview

Problem

Conventional printing apparatuses elongate the printing time due to separate timing of flushing and printing operations, which can lead to inefficiencies and potential clogging of nozzles.

Innovation Solution

A printing apparatus with a print head having both first and second type nozzles, where the second type nozzles are positioned to eject ink towards an ink receiver during flushing, allowing for simultaneous flushing and printing by controlling the nozzles to perform these functions in parallel during main scanning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If flushing and printing are performed separately at different timings, then the flushing operation can be completed thoroughly, but the total printing time becomes elongated

Engineering Contradiction:

Improveflushing completenessVSAvoidprinting time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent combines flushing and printing operations into a single main scanning cycle by positioning second type nozzles (flushing nozzles) and first type nozzles (printing nozzles) at different locations on the print head. During one main scanning movement, the print head simultaneously performs flushing at the ink receiver position and printing at the printing sheet position, merging two previously separate operations into one coordinated action.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The print head is segmented into two distinct nozzle types with different functions: first type nozzles for printing and second type nozzles for flushing. This segmentation allows each nozzle type to operate independently during the same main scanning cycle, enabling parallel execution of flushing and printing without interference.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the print head moves to position the nozzles for flushing, then flushing can be performed, but printing progress is delayed

Engineering Contradiction:

Improvenozzle maintenanceVSAvoidprinting throughput

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent merges flushing and printing into a single main scanning operation. The print head moves once along the main scanning direction, and during this single movement, it simultaneously performs flushing when positioned over the ink receiver and printing when positioned over the printing sheet, eliminating the need for separate movements and improving productivity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The system maintains continuous useful action by ensuring that the print head is productively engaged throughout the entire main scanning cycle. While second type nozzles perform flushing, first type nozzles simultaneously perform printing, ensuring that no time is wasted and the printing process continues without interruption or delay.

Inventive Principle:

Principle #20Continuity of useful action

3Area of stationary object

If multiple nozzles are distributed in both main scanning and sub-scanning directions, then printing coverage is improved, but the distance from some nozzles to the ink receiver increases

Engineering Contradiction:

Improveprinting coverage areaVSAvoidnozzle to ink receiver distance

Core Design Contradiction:

Area of stationary objectVSLength of stationary object

Solution Approach 1:

The patent segments the nozzle array into two functional groups: first type nozzles (printing nozzles) positioned to face the printing sheet, and second type nozzles (flushing nozzles) positioned to face the ink receiver. This segmentation allows nozzles to be distributed across both main scanning and sub-scanning directions for comprehensive coverage, while each nozzle type maintains an optimized distance to its respective target.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the print head are assigned different functional qualities: the region facing the printing sheet contains first type nozzles optimized for printing, while the region facing the ink receiver contains second type nozzles optimized for flushing. This local differentiation allows each nozzle type to operate at optimal distance and angle for its specific function.

Inventive Principle:

Principle #3Local quality

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 reduces printing time by enabling parallel execution of flushing and printing, thereby preventing nozzle clogging and improving overall printing efficiency.

Implementation Method 1

a print head 110 which ejects ink Ik in the form of ink droplets

Methodology Applied

Scientific EffectInkjet ejection:

Data Source

PatentUS11254133B2Printing apparatus and non-transitory computer-readable recording medium for printing apparatus

Publication Date: 2022.02.22 BROTHER KOGYO KK

AI summary

A printing apparatus is provided with a print head having at least a first type nozzles and a second type nozzles positioned on a first direction side with respect to the first type of nozzles and a controller. The controller is configured to perform a first ejection control with performing a main scanning. The first ejection control includes a control of performing flushing when the print head is in a first state where the second type of nozzles are located at a position corresponding to an ink receiver and the first type of nozzles are located at a position corresponding to the medium range, and a control of causing the first type nozzles to eject the ink toward the printing medium during a period where the ink is ejected from the second type of nozzles toward the ink receiver when the print head is in the first state.