Piezoelectric Head Positioning via Dual-Actuator Segmentation
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Solution Overview
Problem
Existing liquid droplet discharging apparatuses, such as ink jet printers, face challenges in accurately adjusting the position of the recording head due to the hysteresis and creep characteristics of piezoelectric elements, leading to errors in liquid droplet discharge positions on the medium.
Innovation Solution
A liquid droplet discharging apparatus that utilizes two piezoelectric elements moving in opposite directions, with a drive control unit that adjusts which element to drive based on the difference between the target and actual movement amounts, allowing for precise correction of discharge positions without being influenced by hysteresis and creep characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single piezoelectric element is used to adjust head position, then the device complexity is reduced, but the manufacturing precision deteriorates due to hysteresis and creep characteristics causing displacement errors
Solution Approach 1:
The single piezoelectric element is segmented into two separate piezoelectric elements (first and second piezoelectric elements) that operate in opposite directions. This segmentation allows the system to select which element to drive based on the correction direction needed, thereby avoiding the hysteresis and creep errors that would accumulate in a single element that must repeatedly expand and contract.
Solution Approach 2:
Instead of using one piezoelectric element that expands and contracts repeatedly (which causes hysteresis and creep), the invention uses two piezoelectric elements that push in opposite directions. By selecting which element to drive based on the sign of the position error, the system avoids the degradation associated with repeated cycling of a single element.
2Measurement precision
If the piezoelectric element is driven to correct position errors, then the head position accuracy is improved, but the reliability deteriorates due to fluctuation in displacement amount caused by hysteresis and creep characteristics
Solution Approach 1:
The piezoelectric actuation system is segmented into two independent elements, allowing the control system to select the optimal element based on the required correction direction. This prevents the reliability issues that arise from repeatedly driving a single element through expansion and contraction cycles, which cause hysteresis and creep-induced displacement fluctuations.
Solution Approach 2:
The invention changes the operational parameter from a single piezoelectric element cycling through expansion and contraction to two elements that can be selectively activated. This parameter change eliminates the hysteresis and creep effects that cause displacement amount fluctuation, thereby improving the reliability of the position correction mechanism.
3Device complexity
If a single piezoelectric element is used for position correction, then the device complexity is reduced, but the manufacturing precision deteriorates due to errors in liquid droplet discharge position
Solution Approach 1:
The single piezoelectric element is divided into two separate elements that can be selectively activated. This segmentation enables the system to correct discharge position errors without the hysteresis and creep effects that plague single-element systems, thereby improving liquid droplet discharge position accuracy while maintaining relatively simple device architecture.
Solution Approach 2:
Instead of using one piezoelectric element that must reverse its action (expand then contract), the invention uses two elements that can be selectively driven in their primary expansion direction. This inversion of the operational approach eliminates the hysteresis and creep effects that cause discharge position errors, improving manufacturing precision.
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 accurate adjustment of the head position relative to the medium, reducing errors in liquid droplet discharge and improving print quality by minimizing the displacement amount of the piezoelectric elements and reducing the fluctuation caused by hysteresis and creep characteristics.
Implementation Method 1
a first piezoelectric element that moves the head in a first direction; a second piezoelectric element that moves the head in a second direction opposite to the first direction
Data Source
AI summary
A liquid droplet discharging apparatus includes: a first piezoelectric element that moves a head in a first direction; a second piezoelectric element that moves the head in a second direction opposite to the first direction; a movement unit that moves a medium in the first direction in accordance with a predetermined target movement amount; a transport amount measurement unit as a movement amount measurement unit that measures a movement amount of the medium in the first direction; and a drive control unit that controls driving of the first piezoelectric element and the second piezoelectric element. The drive control unit drives either one of the first piezoelectric element or the second piezoelectric element according to a difference B−A between a target transport amount A as the target movement amount and a transport amount B as the movement amount measured from the transport amount measurement unit.