Capsule Printing and Inkjet Coding Procedure SOP

Standard operating procedure for qualifying inks and controlling on-capsule printing or inkjet coding, including print quality checks, legibility verification, and adhesion inspection.

Steps

• Verify the work order and approved ink status
  The QA technician verifies that the work order lot number matches the approved ink batch code exactly, confirms the product and code specification are current, and records the reconciliation in the batch record before release.
• Inspect the equipment and print station
  The equipment technician verifies nozzle pressure is 20–25 bar (±2 bar tolerance), nozzle temperature is 45–50 °C, and no visible ink residue or blockage is present; record readings on the Daily Equipment Log; if pressure deviates >2 bar, escalate to maintenance and do not proceed.
• Prepare and identify the ink sample
  The QA technician retrieves the approved ink batch, confirms the batch number, expiry date, and container label against the work order, and stages the sample in a clean tray away from other inks. Acceptance criteria: the ink container is intact, clearly labeled, within expiry, and matches the approved batch record exactly.
• Set the print parameters
  The equipment technician enters the approved code content, print location, font or pattern, and line speed settings into the capsule printing or inkjet coding equipment, then saves the setup record before starting the run. Acceptance criteria: the displayed parameters match the approved specification and are recorded in the setup log.
• Run the initial print sample
  The production operator prints a small sample of capsules using the approved setup and places the sample in the inspection tray without mixing it with released product. Acceptance criteria: the sample is representative of the run and clearly identified for inspection.
• Inspect print legibility and placement
  The QA technician inspects the sample under adequate lighting using a magnifier or inspection loupe, confirms the code is readable, correctly oriented, and within the approved placement tolerance, and records the result on the inspection log. Acceptance criteria: the code is legible, complete, correctly positioned, and matches the approved content with no blur, skip, or misalignment.
• Perform the adhesion check
  The QA technician performs the approved adhesion test on the printed sample, such as rubbing the code with 70% isopropyl alcohol for 10 seconds or using the site-approved equivalent method, and documents the result. Acceptance criteria: the print does not smear, flake, transfer, or lift during the test.
• Release the run or escalate a deviation
  The line supervisor reviews the inspection and adhesion results and determines whether the run may continue or must be escalated. Acceptance criteria: if both checks pass, the run is released; if any defect, legibility issue, or adhesion failure is present, the process is escalated and affected product is held.
• Continue production and monitor at defined intervals
  The production operator continues the run and performs periodic checks at the defined batch interval, confirming print quality, placement, and adhesion remain within specification. Acceptance criteria: all scheduled checks are documented and remain within the approved limits throughout production.
• Quarantine affected product and notify supervision
  The quality technician or line supervisor immediately segregates all affected capsules, applies quarantine identification, and notifies supervision and quality for deviation review. Acceptance criteria: affected product is clearly labeled, physically separated from conforming product, and a deviation report is initiated.