How to troubleshoot ink leakage in a CIJ printer

CIJ Inkjet Ink Selection Guide for Harsh Industrial Environments In harsh industrial environments (extreme temperature and humidity, strong corrosion, high abrasion, special substrates, etc.), the selection of CIJ inks directly determines the labeling durability, equipment failure rate, and production line stability. The selection process must be completed in four steps: "Scenario Anchoring → Indicator Matching → Specific Adaptation → Implementation Verification." The core requirements are as follows:

Step 1: Identify Core Harsh Scenarios Before selecting a system, it's necessary to analyze the extreme operating conditions throughout the entire production and usage process. These typically include the following five types of harsh scenarios:

Step 2: Core General Selection Criteria (Applicable to All Scenarios) Regardless of the harsh environment, the following four key indicators must be prioritized to avoid compatibility issues later:

1.Environmental Compatibility Criteria: Prioritize inks with a wide viscosity window, ensuring viscosity fluctuations do not exceed 15% within the 0-60℃ range. This prevents abnormal droplet splitting, ink line breaks, or ink leakage caused by temperature changes. For high-humidity environments, choose fast-drying inks with a drying speed of 1-3 seconds to avoid ink smudging. For high-temperature environments, choose inks with high-boiling-point solvent formulations to reduce the risk of nozzle drying due to rapid solvent evaporation.

2.Adhesion and Durability Criteria: Prioritize formulations with a resin system of "vinyl chloride-vinyl acetate copolymer + hydrogenated rosin ester tackifier." These inks exhibit over 40% higher adhesion to difficult-to-adhere substrates such as HDPE and PP compared to ordinary solvent inks. They can pass basic tests such as 10 rubs on kraft paper without blurring and no transfer when applied with tape. For outdoor scenarios, select inks with a weather resistance rating of ≥3 to ensure no fading of markings after 6 months of outdoor exposure.

3.Ink Compatibility Indicators: CIJ inks are designed for recyclability, so compatibility between the ink and the equipment's ink path components (pump, seals, tubing) must be confirmed: MEK-based inks must be compatible with PTFE membranes and FFKM valves to prevent long-term corrosion and leakage; models with a nozzle residual redissolution rate of ≥50% should be prioritized, allowing residual ink to dissolve quickly after shutdown, reducing the probability of nozzle clogging in high-dust environments.

4.Compliance and Environmental Indicators: Ink must comply with relevant industry standards. For example, inks for the ceramic industry must meet the standard "Solvent-Based Ceramic Inkjet Printing Inks" (T/CBMF 16-2016), which prohibits the use of 27 banned solvents; inks for food contact applications must comply with GB 4806.1 to avoid the risk of hazardous substance migration.

Step 3: Specialized Ink Selection Solutions for Typical Harsh Scenarios

For different harsh operating conditions, corresponding specialized ink solutions can be directly matched:

• Extreme Temperature and Humidity/High Dust Scenarios: Select wide-temperature weather-resistant, fast-drying inks with an applicable temperature range of -10℃ to 65℃ and a drying time of ≤2 seconds. These inks also possess low volatility to prevent ink from failing to dry under high humidity or excessive viscosity at low temperatures, which could lead to printing abnormalities. A representative model is the Videojet V421 series.
  
• Strong Corrosion/Solvent Contact Scenarios: Select solvent-resistant specialty inks, such as the Videojet V484-C model. These inks can withstand wiping with common organic solvents even without a coating and have good compatibility with polyurethane, epoxy, and UV surface coatings. After coating, there will be no ink dissolution or blurring of markings, making them suitable for marking requirements in aerospace and chemical components.
  

• High-abrasion/heavy-transport scenarios: Choose high-abrasion-resistant pigment inks, such as EBS-specific pigment inks, which contain modified terpene resin abrasion-resistant components. They withstand ≥20 abrasions on kraft paper and do not peel off even when scratched with a fingernail, enduring bumps and abrasions during long-distance transportation. Suitable for building materials, auto parts, and logistics packaging.
  
• Difficult-to-adhere substrate scenarios: Choose specialized tackifying inks. These contain approximately 10% hydrogenated rosin ester tackifier in the formula, allowing direct printing on substrates such as HDPE, PP, and stainless steel without pretreatment. Adhesion is improved by over 60% compared to ordinary inks, preventing label peeling.
  
• Food/pharmaceutical compliance scenarios: Prioritize food-grade/pharmaceutical-grade inks certified by the corresponding industry. Food industry inks require a GB 4806.1 test report, while pharmaceutical industry inks must comply with GMP regulations to avoid ink contamination of the product.
  

Step 4: On-the-ground Verification and Pitfall Avoidance Process

To avoid inaccurate parameter claims, three practical tests must be completed during the selection phase:

Field Trial Spray Test: Using actual production substrates and under real-world operating conditions, conduct trial spraying to confirm drying speed, label clarity, and a QR code scanning rate of ≥95%;

Aging Simulation Test: Simulate the product's entire lifecycle environment, completing high and low temperature cycling, abrasion resistance, and solvent resistance tests to confirm label durability meets requirements;

Long-Term Operation Test: Load the ink into the equipment and run it continuously for 72 hours, checking for corrosion, ink leakage, and frequent printhead clogging in the ink path components to confirm compatibility with the equipment.

If you have specific operating scenarios, please let me know, and I can provide you with more precise ink selection advice.