I. Core Testing Logic: Design Essence and Advantages of 16-Level Grayscale Patches (A) Structural Design of 16-Level Grayscale Patches Gradient Division Standard The 16-level grayscale is designed according to the principle of “uniform luminance increment,” covering the full grayscale range from 0% (pure white, no ink coverage) to 100% (pure black, maximum ink coverage). Each grayscale step theoretically differs by 6.25% (100% ÷ 16), with coverage ratios (percentage of ink coverage area) increasing incrementally from 0%, 6.25%, 12.5%, … up to 100%. The standard size of each patch is 15mm × 15mm, with a spacing of 2mm to avoid ink bleeding between adjacent patches. The design refers to the ISO 19751-2 digital printing grayscale testing standard. Differences Compared with Other Grayscale Testing Tools Testing Tool Number of Gradients Core Test Objective Advantageous Scenarios Limitations 16-Level Grayscale Patch 16 (0%-100% full coverage) Grayscale discernibility, density deviation from theoretical value Routine quality control, density calibration Gradient interval slightly wide, cannot capture subtle luminance differences 256-Level Grayscale Image 256 (0-255 grayscale values) Smooth gradient transitions, micro-scale grayscale transitions High-end image print calibration Visual inspection difficult; requires professional instruments Photo Area Grayscale Background Continuous gradient (no clear division) Visual gray balance, scene-specific grayscale performance Comprehensive effect verification Cannot quantify density differences Core Conclusion: The primary value of the 16-level grayscale patch lies in its “balance of intuitiveness and quantifiability”—it allows for rapid visual inspection while enabling precise density calibration via instruments, making it a standard module for grayscale performance testing in digital inkjet systems.

1. Polarization Direction and Piezoelectric Response The polarization direction of piezoelectric materials such as PZT (Lead Zirconate Titanate) determines their electromechanical coupling characteristics. When the direction of the applied electric field is aligned with the polarization direction, the material undergoes direct mode deformation (longitudinal strain) along the polarization axis, manifested as axial expansion (d33 effect). At the same time, due to the Poisson effect, contraction occurs in the transverse directions while the overall volume remains approximately constant. If the electric field is applied perpendicular to the polarization direction, it induces shear mode deformation (transverse strain). In this case, the rotation of dipoles dominates the motion, resulting in pure shear deformation (d31/d15 effects). 2. Physical Mechanism of Direct Mode Electric field parallel to the polarization direction: The electric field drives dipoles to align along the polarization direction, causing lattice distortion (such as the displacement of Pb²⁺ ions), which produces axial strain (ε33). Volume conservation: Transverse contraction (ε11 = ε22) balances axial expansion, resulting in minimal macroscopic volume change. Application scenarios: Devices requiring axial deformation, such as: Ultrasonic transducers Precision displacement actuators 3. Physical Mechanism of Shear Mode Electric field perpendicular to the polarization direction: Dipoles rotate under the influence of the transverse electric field (90° domain wall motion), generating shear strain (γ15). Domain wall motion: Non-intrinsic effects (domain wall movement) dominate the response. This significantly increases the dielectric constant but introduces noticeable hysteresis effects. Application scenarios: Devices requiring transverse deformation, such as: Shear wave sensors Vibration energy harvesters 4. Mode Comparison

Analysis of the “Air Blockage” Issue in Thermal Inkjet Printheads The “air blockage” issue in thermal inkjet printheads is usually caused by gas entering the liquid channel or pressure imbalance within the ink system. The following outlines the main causes and corresponding solutions. I. Analysis of Common Causes 1. Gas Ingress After the equipment stops operating, if the pipeline is not purged in time, residual gas mixes with the liquid and forms air blockages in the ink path. 2. Insufficient Ink Defoaming Performance If the defoaming agent in the ink becomes ineffective or the formulation is improper, bubbles may accumulate in the ink path and enter the printhead, causing air blockage. Bubbles may also be drawn into the printhead due to pressure fluctuations in the ink circulation system, such as air leakage in the negative pressure system or pressure imbalance. 3. Improper Operation Frequent start-stop operation of the equipment or failure to clean the printhead according to specifications may cause residual bubbles to remain in the system. If the printhead is not installed vertically (for example, with excessive tilt), bubbles may become trapped inside. 4. Environmental and Maintenance Issues In high-temperature environments, ink may deteriorate or decompose, generating gas or impurities. Long-term inactivity may cause the ink to dry out, and when the equipment is restarted, air bubbles may enter the system. 5. Pressure Abnormalities Air leakage or pressure fluctuations in the pressure system may cause uneven mixing, allowing gas to remain trapped in the printhead. Two-Dimensional X-ray Imaging of

I. Core Testing Logic: The Design Essence and Coverage Dimensions of CMYK Full Color Patch (A) Structural Design Specifications of Full Color Patch 1. Patch Composition The test chart contains two core types of patches, each single patch ≥50mm × 50mm, with spacing ≥10mm to avoid ink bleed interference:   Single-color full patches: Independent full patches of C (Cyan), M (Magenta), Y (Yellow), K (Black), without any pattern interference, focusing on density and uniformity of a single color. Overlaid color full patches: Five groups of multi-color overlaid full patches—CM (Blue), MY (Red), CY (Green), CMY (Light Black), CMYK (Pure Black)—used to verify color mixing accuracy and registration precision. Some high-end test charts include gradient overlay patches (e.g., gradient from C to CM full patch) to assess the smoothness of color transitions. 2. Core Difference from Single-color Patch Tests   Test Module Size Specification Core Testing Goal Advantageous Scenarios Limitation Single CMYK Patch 10-20mm × 10-20mm Preliminary density check of a single color, visual color reproduction Quick QC, start-up calibration Cannot reflect uniformity in large-area prints or registration issues in multi-color overlays CMYK Full Color Patch ≥50mm × 50mm full patch Large-area density uniformity, multi-color overlay accuracy, registration precision, ink compatibility Equipment acceptance, pre-batch production calibration Higher material consumption, longer testing time than single-color patches Key Conclusion: The main value of CMYK full color patches lies in “point-to-area performance verification” — single-color patches validate local color accuracy, while full color patches assess large-area printing stability and multi-color collaboration accuracy, serving as

The core characteristics of piezoelectric Drop-on-Demand (DOD) inkjet technology are closely related to fluid dynamic behavior. Factors such as nozzle shear rate, dynamic viscosity, polymer molecular weight, and solid loading significantly influence droplet formation and print quality. The following is a comprehensive analysis. I. Nozzle Shear Rate and Dynamic Viscosity 1. Shear Rate Characteristics The shear rate of piezoelectric DOD printheads is significantly lower than that of Continuous Inkjet (CIJ) technology, as it relies on pulsed pressure rather than a continuous jet stream. A low shear rate (typically <10⁴ s⁻¹) can reduce the shear-thinning effect of high-viscosity inks, but dynamic viscosity adjustment is still required to ensure stable droplet break-up. 2. Jet Break-Up Control Droplet formation depends on the rate of change of shear rate (dγ/dt), which must match the deformation speed of the piezoelectric crystal. Experimental results show that when dγ/dt exceeds a critical threshold (approximately 10⁵ s⁻²), the jet breaks into uniform microdroplets due to inertial forces dominating the process. II. Polymer Molecular Weight and Print Quality 1. Influence of Molecular Weight Ligament Length: High molecular weight polymers (such as PVA) can increase ligament length (L ∝ √(η/ρ)). However, excessively high molecular weight (>100 kDa) may cause droplet tailing. Throw Distance: Increasing molecular weight reduces droplet kinetic energy (E ∝ 1/η), which shortens the droplet throw distance. This effect must be compensated by adjusting the piezoelectric driving voltage. 2. Print Resolution Optimization Low molecular weight binders (<5 kDa) can improve droplet positioning accuracy, but a balance must be

I. Installation Adaptation and Hardware Compatibility Control (1) Mechanical Installation Accuracy Assurance 1. Positioning and Distance Calibration The Emerald series printhead adopts a high-precision nozzle array design. During installation, a micron-level adjustment platform (repeat positioning accuracy ≤0.01 mm) must be used to ensure the distance between the nozzle surface and the printing substrate is controlled within 1.2–2.0 mm. The distance should be slightly adjusted according to ink type: Water-based ink: 1.5–2.0 mm UV ink: 1.2–1.8 mm Parallelism deviation must be < 0.02 mm/m. The mounting bracket should be made of rigid aluminum alloy (load capacity ≥3 kg), and shock-absorbing pads should be installed (thickness 2 mm, hardness Shore 70°) to reduce the impact of machine vibration on jetting accuracy. 2. Heat Dissipation and Protection Design A heat dissipation clearance of ≥30 mm must be reserved on the side of the printhead. The nozzle surface should be installed with a 1° downward tilt (±0.1°). This angle reduces the probability of UV ink curing residues and also lowers the risk of ink accumulation with eco-solvent inks. For outdoor printing environments, an additional dust-proof protective cover should be installed (protection level IP54). Moisture-absorbing cotton strips should be attached inside the cover (replaced every 24 hours) to prevent dust and moisture from entering the nozzle chamber. (2) Electrical Connection Anti-Interference Specifications 1. Cable and Connector Compatibility The driver signal cable must use original dual-layer shielded cables: Outer layer: tinned copper mesh Inner layer: aluminum foil Cable length must not exceed 1.8 m. Connectors should

Among the influencing factors of ink buildup on inkjet printer printheads, the printhead waveform, temperature, and humidity are often overlooked but critically important aspects. The printhead waveform directly determines the ink ejection behavior, while temperature and humidity indirectly aggravate or alleviate ink accumulation problems by affecting the physical properties of ink and the working environment of the printhead. The following provides a systematic analysis of the core mechanisms by which these three major factors lead to ink buildup and corresponding solutions, complementing the previous discussion. I. Causes and Solutions of Ink Buildup Caused by Abnormal Printhead Waveforms The printhead waveform refers to the driving voltage curve used by the printer to control ink ejection from the printhead (including parameters such as voltage peak, duration, and waveform frequency). Its stability directly affects ink ejection velocity, droplet size, and residual ink, and abnormalities can easily cause ink buildup. 1. Core Cause: Waveform Parameters Deviating from Standards Leading to Ink Residue or Incomplete Ejection Low Voltage Peak If the driving voltage peak is lower than the standard value (typically 20–40V, depending on the printer model), the ink receives insufficient ejection force and cannot completely detach from the nozzle. Part of the ink remains at the nozzle edge. This residual ink quickly dries in the air and gradually accumulates, forming ink buildup. Subsequent ink droplets may adhere to the residue, worsening nozzle blockage. Excessive Waveform Duration The duration of the driving voltage determines the time the ink is “compressed” within the nozzle. If the

Analysis of Surface Tension Effects on Inkjet Printing   The following is a comprehensive analysis of how surface tension affects inkjet printing, integrating key points on pigment dispersion, surface energy, and inkjet processes: 1. Physicochemical Basis of Surface Tension and Pigment Dispersion Gibbs Free Energy and New Surface Formation: When dispersing pigments, particle breakup must overcome intermolecular forces (e.g., van der Waals forces). The energy required equals the Gibbs free energy of creating a new surface (ΔG=γ⋅ΔA\Delta G = \gamma \cdot \Delta AΔG=γ⋅ΔA), where surface tension (γ\gammaγ) is the work per unit area. Dynamic Equilibrium: During grinding, mechanical shear breaks pigment aggregates. However, if the new surface is not rapidly wetted (e.g., with low-surface-tension dispersants), the high surface energy causes spontaneous re-aggregation. 2. Influence of Surface Tension on Inkjet Processes Wetting and Flow: In inkjet printing, ink must spread on the substrate surface (wetting). Excessively high surface tension causes droplet contraction, leading to “coffee ring” effects or poor adhesion. Wet film leveling relies on surface tension gradients (solvent evaporates faster in thin areas, increasing local surface tension, driving coating flow toward high-tension regions). Satellite Droplet Control: During ink breakup, surface tension combined with viscoelasticity determines filament breakage behavior. High surface tension tends to elongate filaments, increasing satellite formation (e.g., mineral oil-based binders are more prone to satellite droplets than resin-based). Adding surfactants (e.g., “wetting” agents) reduces the surface tension of water-based inks, improving jetting stability. 3. Pigment Surface Treatment and Dispersant Selection Surface Polarity Control: Organic pigments (hydrophobic) and inorganic

Technical Characteristics of Piezoelectric Printheads   1. High Manufacturing Cost, Not Designed as Disposable Reason: Piezoelectric printheads use precision ceramic piezoelectric elements and complex ink channel structures. The materials and manufacturing processes result in significantly higher costs compared with thermal inkjet printheads. Advantage: The non-disposable design (for example, Kyocera printheads can reach hundreds of millions of firing cycles) reduces long-term operating costs and is suitable for industrial high-duty applications. 2. High Printhead Cost Leads to Higher Product Cost Cost Structure: The unit price of a piezoelectric printhead is typically 3–5 times higher than that of a thermal inkjet printhead. This is mainly due to the ceramic materials, driver circuits, and high-precision manufacturing processes. Market Impact: High-end equipment (such as UV flatbed printers) has a significantly higher overall machine price because the printhead represents a large portion of the total cost. However, the use of compatible inks can help reduce consumable costs. 3. Very High Printhead Reliability Technical Assurance: Ceramic materials provide strong corrosion resistance. Printheads from brands such as Kyocera can maintain stable ink ejection even under 60 kHz high-frequency driving, and their failure rate is lower than that of thermal inkjet printheads. Maintenance Cost: Regular cleaning is required (such as using dedicated cleaning solutions), but due to the stable structure, the maintenance frequency is relatively low during long-term operation. 4. Greater Freedom in Ink Development Compatibility Advantage: Piezoelectric printheads have higher tolerance for ink parameters such as viscosity and conductivity. They support various ink types including water-based inks, UV

I. Core Principle: The Working Logic of the Waveform Ink Path A waveform is essentially a voltage timing signal that drives the piezoelectric ceramic (PZT) in the printhead. It controls the state of the ink path through the slope of the ramp section (rate of voltage change) and the holding time (duration of voltage stabilization): Ink Path Pressure Regulation: Voltage changes cause the PZT to expand and contract, altering the volume of the ink chamber. When the voltage decreases, the chamber expands and draws in ink; when the voltage increases, the chamber contracts and ejects ink droplets. This process relies on the precise transmission of pressure waves. Ink Motion Synchronization: Waveform pulses must match the pressure resonance of the ink inside the chamber, similar to controlling the timing of “pushing a swing.” Correct timing enhances droplet momentum, while incorrect timing causes impact disturbances. Multi-Pulse Coordination: Complex waveforms adjust droplet size through multi-pulse superposition, but this must strictly match the resonance cycle of pressure waves; otherwise, abnormal nozzle pressure will occur. II. Three Major Mechanisms by Which Abnormal Waveform Ink Paths Cause Needle Breakage Needle breakage (including nozzle clogging and fatigue fracture of needle-like structures) is directly caused by ink path pressure imbalance or mechanical impact, while mismatched waveform parameters are the core root cause. 1. Pulse Timing Mismatch: Pressure Resonance Conflict Principle: The ink chamber can be regarded as a “damped resonator.” The cycle of pressure wave propagation inside the chamber is determined by the chamber length and the sound