Ink-jet Head Drive Device Impedance Control
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Solution Overview
Problem
In ink-jet recording apparatuses, the steep change in voltage applied to piezoelectric members during simultaneous positive and negative direction potential changes leads to noise and erroneous operations, requiring additional detection circuits for each channel, resulting in increased IC size and cost.
Innovation Solution
The ink-jet head drive device employs a voltage selecting mechanism and drive waveform transition control to manage voltage output through low-impedance and high-impedance circuits, ensuring stable voltage transitions without the need for detection circuits, thereby reducing noise and IC size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If detection circuits are added to each channel drive circuit to detect when potential changes simultaneously in the same direction, then noise and erroneous operations are reduced, but IC size increases
Solution Approach 1:
The invention extracts the voltage change detection function from individual channel drive circuits and implements it at the voltage selecting mechanism level. By monitoring potential changes at the voltage selection point rather than at each channel output, the system achieves noise detection capability without replicating detection circuits across multiple channels, thus reducing overall IC area while maintaining operational reliability
Solution Approach 2:
The voltage selecting mechanism serves multiple functions: it selects appropriate voltages for different channels, monitors voltage changes across all channels, and controls the impedance switching based on detected changes. This multi-functional approach eliminates the need for separate detection circuits in each channel, reducing IC size while maintaining noise detection and prevention capabilities
2Reliability
If detection circuits are added to each channel drive circuit to detect when potential changes simultaneously in the same direction, then noise is reduced, but manufacturing cost increases
Solution Approach 1:
By extracting the detection function from individual channel circuits and implementing it centrally at the voltage selecting mechanism, the invention reduces the total number of detection circuits required. This reduction directly lowers manufacturing costs while maintaining the ability to detect and prevent noise caused by simultaneous potential changes
Solution Approach 2:
The invention merges the detection circuit functionality into the voltage selecting mechanism, combining voltage selection and voltage change detection into a single integrated unit. This consolidation reduces the total component count and simplifies manufacturing, lowering production costs while maintaining operational reliability
3Speed
If voltage changes steeply when piezoelectric member is unloaded, then response speed is fast, but noise is generated
Solution Approach 1:
The invention applies preliminary anti-action by detecting voltage changes that would cause the piezoelectric member to become unloaded and preemptively switching the connecting circuit to high-impedance mode. This prevents the steep voltage change and associated noise before it occurs, rather than attempting to correct it after the fact
Solution Approach 2:
The invention introduces an intermediary mechanism (the impedance switching circuit controlled by the voltage selecting mechanism) that mediates between the voltage source and the piezoelectric member. When unloading is detected, this intermediary switches to high-impedance mode, preventing direct voltage application and thus preventing noise-generating steep voltage changes while maintaining system responsiveness
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 effectively reduces noise and IC size by stabilizing voltage transitions across piezoelectric members, allowing for efficient ink ejection without the necessity of additional detection circuits, thereby lowering manufacturing costs.
Implementation Method 1
Piezoelectric members are used as the actuators. An electrode is attached to each piezoelectric member, and drive voltage with predetermined drive waveforms is applied to electrodes at both ends of the piezoelectric member arranged between a channel as a target of ink ejection and a channel adjacent to the channel. If the drive voltage is respectively applied to the electrodes at both ends, the piezoelectric member performs a deforming operation in accordance with a potential difference between the electrodes at both ends.
Data Source
AI summary
A drive device includes a circuit for selecting an arbitrary voltage among a plurality of kinds of voltages required for generating a drive signal for variably controlling potential applied to electrodes of channels. In the drive device, respective drive voltage input terminals and output terminals are respectively connected by a low-impedance connecting circuit which has low internal resistance, and a selected voltage input terminal and the output terminals are connected by a high-impedance connecting circuit which has high internal resistance. The drive device controls a drive waveform transition pattern of a drive signal such that the drive signal is output via the high-impedance connecting circuit while the potential applied to the respective electrode simultaneously changes in the same direction out of a positive direction and a negative direction and that the drive signal is output via the low-impedance connecting circuit in the other cases.