Dynamic Phase Shifts for Continuous Inkjet Print Quality
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Solution Overview
Problem
Existing continuous inkjet printing technologies face challenges in maintaining high print quality at low and medium speeds, as closely spaced small drops lead to aerodynamic interactions causing 'splay' errors, which are not effectively addressed by previous methods like those described in US Published Patent Application US 20080231669, which only improve quality at high speeds.
Innovation Solution
A method involving a liquid drop emitter with nozzles arranged in groups, where each nozzle is interleaved with others, and drop forming energy pulses are applied to create drops of different sizes with specific timing sequences to form non-print and print drops according to liquid pattern data, including a delay time that dynamically adjusts based on print speed to minimize aerodynamic interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If closely spaced small drops are used to achieve high resolution printing, then manufacturing precision is improved, but aerodynamic interactions cause splay errors that worsen reliability
Solution Approach 1:
The nozzle array is divided into multiple independently controllable groups, allowing selective activation of nozzles to reduce drop density and aerodynamic interactions while maintaining print quality through coordinated operation of grouped nozzles
Solution Approach 2:
The system dynamically adjusts the operation of individual nozzles or nozzle groups based on real-time printing conditions, enabling adaptive control of drop ejection timing and patterns to minimize aerodynamic interference and optimize placement accuracy across varying print speeds
2Reliability
If phase shifting is applied to reduce splay errors at low speeds, then reliability is improved, but device complexity increases due to additional control mechanisms
Solution Approach 1:
The existing nozzle grouping infrastructure is extended to incorporate phase shifting functionality, allowing the same hardware architecture to serve multiple purposes: standard operation mode and phase-shifted operation mode for low-speed printing, thereby avoiding additional dedicated hardware complexity
Solution Approach 2:
The system changes operational parameters (phase shifts between nozzle groups) rather than modifying physical hardware, allowing dynamic adjustment of drop ejection timing relationships to reduce splay errors through software-controlled parameter variation instead of mechanical complexity
3Reliability
If multiple nozzle groups with phase shifts are used to improve low-speed printing, then reliability is improved, but productivity decreases due to coordinated timing requirements
Solution Approach 1:
The system employs periodic phase shifting patterns between nozzle groups, creating rhythmic coordination that simplifies timing calculations and enables predictable, repeatable drop placement sequences, thereby maintaining productivity while improving reliability through systematic phase management
Solution Approach 2:
Phase shift values and timing relationships are pre-calculated and stored for different printing conditions, allowing the control system to simply retrieve and execute predetermined timing sequences rather than performing complex real-time calculations, thus maintaining high processing speed while achieving improved drop placement reliability
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 improves image quality across all print speeds except maximum speed by optimizing drop placement and reducing splay errors, enhancing the reliability and precision of the printing process.
Implementation Method 1
closely spaced small drops lead to aerodynamic interactions causing 'splay' errors
Data Source
AI summary
A method of forming print drops includes forming drops of a first size by applying drop forming energy pulses during a unit time period, τ0; forming drops of a second size by applying drop forming energy pulses during a second drop time period, τm, wherein the second drop time period is a multiple, m, of the unit time period, τm=m*τ0, m≧2; providing timing between drops for printing consecutive pixels is τi=a*τ0 where a is an integer≧m; forming non-print drops and print drops according to the liquid pattern data; delaying the timing of the pulses for the drop forming energy pulses sent to the drop forming transducers of group number g relative to the drop forming energy pulses sent to the transducers of a first group by a delay time τL, where τL=g*(INT(a/n)+1/n)*τ0+τb where g is an integer<n.