SOP for Cleaning of Overprinting Machine (Example Template)

In short: This example SOP describes how packing staff clean an inkjet overprinting (batch-coding) machine between products and batches so that no ink cartridge residue, dust or previously printed batch details remain. It covers labels, hold times and records. Adapt the machine names, times and forms to your own quality system before use.

Why this cleaning matters

An overprinting machine prints the batch number, manufacturing and expiry dates and price on cartons, labels or foils. If the previous batch’s coding data, printed material or dust stays on the machine, a wrong batch number or date can reach the market. Two GMP expectations apply:

• 21 CFR 211.67 (US FDA, Equipment cleaning and maintenance) requires written cleaning procedures that cover responsibility, schedules, detailed methods, removal or obliteration of previous batch identification, protection of clean equipment before use, and inspection for cleanliness immediately before use. Cleaning and inspection records must be kept (§211.67(c), with §§211.180 and 211.182).
• EU GMP Part I, Chapter 5 (Production), paragraph 5.50 expects that, before packaging starts, the work area, packaging lines, printing machines and other equipment are clean and free from products, materials or documents from the earlier operation, and that line clearance follows a checklist.

1. Objective

To describe the procedure for cleaning an inkjet overprinting machine and effectively removing residue of the previous product or batch.

2. Scope

This example SOP applies to cleaning of inkjet overprinting machines (for example HSAJET TCU or Minitouch type units) in the packing area of the manufacturing facility. Replace the placeholders with your own site and equipment details.

3. Responsibility

• Packing officer / executive: clean the machine as per this procedure and record it.
• Head of Packing: ensure the procedure is implemented and followed.
• Quality Assurance: verify line clearance and review the cleaning records.

4. Procedure

4.1 Health, safety and environment

Switch off the electrical supply before starting cleaning.

4.2 Product-to-product and batch-to-batch cleaning

1. Switch off the mains of the overprinting machine.
2. Remove the “USE FOR” (in use) status label and affix a “TO BE CLEANED” label on the machine.
3. Remove the ink cartridge from the cartridge holder, following the machine manual or the diagram in your site SOP.
4. Clean the cartridge head with clean tissue paper. Take care not to damage the circuit contacts while removing or refitting the cartridge.
5. Clean the conveyor belt and the printing unit with a clean, dry, lint-free duster.
6. Check that no printed material, cartons, labels or coding data of the previous batch remain on or in the machine. Clear the print message of the previous batch from the controller, as defined in your coding procedure.
7. Remove the “TO BE CLEANED” label and affix a “CLEANED” label showing the equipment code, previous product, SOP number, cleaned by (signature), date, and the date until which the cleaning remains valid (“CLEANED VALID UP TO”).
8. Record the cleaning in the area and equipment usage and cleaning log.

4.3 Hold time after cleaning (example in-house criteria)

• If the cleaned machine stays unused for 48 hours, or if dust or powder is visible on its outer surfaces, wipe it with a damp lint-free duster followed by a clean dry lint-free duster.
• If the machine stays unused for more than 72 hours after cleaning, clean it again before use.

5. Records

Keep the cleaning log and status labels’ records as part of the packaging documentation. Records must be retained for at least 1 year after the expiry date of the respective product batch (EU GMP Part I, Chapter 4, paragraph 4.11; 21 CFR 211.180(a)), or longer if local law or the marketing authorisation requires.

6. Training

• Trainer: Head of Packaging.
• Trainees: Packing department staff who clean the machine.

7. Distribution

Controlled copies to Head of Quality Assurance and Head of Packaging; original with Quality Assurance.

8. Abbreviations

• SOP: Standard Operating Procedure
• QA: Quality Assurance
• GMP: Good Manufacturing Practice

Frequently asked questions

Is cleaning the overprinting machine the same as line clearance?

No. Line clearance checks that the packing line and area are free of previous materials and documents before a new batch starts (EU GMP Chapter 5, paragraph 5.50). Cleaning of the machine is one of the steps that supports it. Both are recorded.

Do we need to validate this cleaning?

Overprinters are non-product-contact equipment, so visual checks and a defined routine are normally used. Whether any further verification is needed depends on your own risk assessment. See the general principles in Principles of Cleaning Validation.

Why remove the previous batch message from the controller?

A stored message can be printed by mistake on the next batch. Clearing it and checking the first printed sample against the batch packaging record prevents wrong batch numbers or dates.

See also

• SOP for Cleaning of Blister Pack Machine
• SOP on Cleaning Validation
• Cleaning Validation Protocol Format

References

• US FDA, 21 CFR Part 211, §211.67 Equipment cleaning and maintenance (current eCFR text), §211.180 and §211.182.
• European Commission, EudraLex Volume 4, EU GMP Part I, Chapter 5: Production, paragraph 5.50 (revision in operation from 1 March 2015).
• European Commission, EudraLex Volume 4, EU GMP Part I, Chapter 4: Documentation, paragraph 4.11.