Inkjet Recording Device Sub-Tank Ink Supply Control

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Solution Overview

Problem

Conventional inkjet recording devices face inefficiencies in ink supply management, leading to premature operation stops and decreased efficiency due to small allowances in ink storage tank capacity, which can be exacerbated by increased sensor usage or tank capacity, resulting in inadequate handling of ink storage abnormalities.

Innovation Solution

The implementation of an inkjet recording device with a sub-tank system that includes a main tank, a sub-tank, and a controller to manage ink supply based on sensors detecting standard, lower limit, and upper limit storage amounts, allowing for efficient ink distribution and preventing operation interruptions by adjusting the ink flow path and pump operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the capacity of the second tank is increased to provide larger allowance for ink storage abnormalities, then the reliability of continuous operation is improved, but the device complexity and space requirements increase

Engineering Contradiction:
Improvecontinuous operation capabilityVSAvoidtank capacity configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The ink storage system is divided into a first tank (main tank) and a second tank (sub tank), where the first tank serves as the primary ink source and the second tank acts as a buffer. This segmentation allows the second tank to be kept at a compact size while the first tank provides the necessary ink reserves, resolving the contradiction between reliability and device complexity.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If more sensors are added to detect ink storage abnormalities accurately, then the measurement precision is improved, but the device complexity increases

Engineering Contradiction:
Improveink storage amount detection accuracyVSAvoidsensor quantity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of uniformly distributing multiple sensors throughout the ink storage system, a single detection sensor is strategically placed in the second tank to monitor ink levels. This localized sensing approach achieves sufficient measurement precision for detecting ink storage abnormalities without the complexity of multiple sensors.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system proactively supplies ink from the first tank to the second tank before the second tank becomes empty, based on predetermined ink storage amounts. This preliminary action allows accurate detection of ink status with minimal sensing while maintaining continuous operation capability.

Inventive Principle:
Principle #10Preliminary action

3Loss of time

If the capacity of the second tank is increased to handle ink storage abnormalities, then the loss of time for operation interruption is reduced, but the volume of the device increases

Engineering Contradiction:
Improveoperation interruption timeVSAvoidsecond tank capacity
Core Design Contradiction:
Loss of timeVSVolume of stationary object

Solution Approach 1:

The ink storage function is segmented between two tanks with different roles: the first tank provides bulk ink storage, while the second tank maintains a minimal buffer capacity sufficient to prevent operation interruptions. This segmentation eliminates the need for a large single tank, reducing overall device volume while maintaining operational continuity.

Inventive Principle:
Principle #1Segmentation

4Ease of operation

If the ink supply control is based on empty/full detection only, then the ease of operation is improved, but the productivity decreases due to premature operation stops

Engineering Contradiction:
Improveink supply control simplicityVSAvoidoperation efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The control system proactively supplies ink from the first tank to the second tank when the ink level in the second tank reaches a predetermined threshold before complete depletion. This preliminary action prevents premature operation stops and maintains high productivity while keeping the control logic simple and easy to operate.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The detection sensor provides continuous feedback on the ink storage amount in the second tank, enabling the control unit to automatically adjust ink supply timing. This feedback mechanism optimizes productivity by preventing operation interruptions while maintaining ease of operation through automated control.

Inventive Principle:
Principle #23Feedback

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 solution enables more efficient handling of ink storage abnormalities, ensuring continuous operation by maintaining suitable ink levels in the sub-tank, reducing the need for excessive sensors or tank capacity, and allowing for timely notification and prevention of ink-related issues.

Implementation Method 1

an inkjet head (211) which ejects ink

Methodology Applied
Scientific EffectInkjet ejection:

Implementation Method 2

a supplying pump which sends ink from the main tank (31) to the sub-tank (251)

Methodology Applied
Scientific EffectPump: Pump

Implementation Method 3

one or a plurality of liquid sending pumps (253) which send ink from the sub-tank (251) to the inkjet head (211)

Methodology Applied
Scientific EffectPump: Pump

Data Source

PatentEP3437884B1Inkjet recording device
Publication Date: 2021.10.13 KONICA MINOLTA INC
  • EP3437884B1 patent drawingFigure 1
  • EP3437884B1 patent drawingFigure 2
  • EP3437884B1 patent drawingFigure 3

AI summary

Provided is an inkjet recording device capable of supplying ink to a head while responding to abnormalities in the ink storage level with more appropriate operation efficiency. The present invention is provided with: an inkjet head 211; a main tank 31; a sub-tank 251 for storing supply ink from the main tank 31; a supplying pump 32 for sending ink from the main tank 31 to the sub-tank 251; a liquid delivery pump 253 for sending ink from the sub-tank 251 to the inkjet head 211; a reference sensor 251a, maximum sensor 251c, and minimum sensor 251b for determining whether ink of a prescribed reference storage amount, ma ximum storage amount, and minimum storage amount, respectively, are stored in the sub-tank 251; and a control unit 40 for determining whether to operate the supplying pump 32 in accordance with the detection result of the reference sensor 251a, and performing a prescribed abnormality response operation in accordance with the detection results of the maximum sensor 251c and the minimum sensor 251b.