Recognise the symptom before changing settings
Describe what changes, where it first appears and whether it follows a product batch, packaging batch, filling head, lane, speed, temperature or time in the run. Typical observations include:
- characters are faint, broken or blurred
- code position moves
- ink rubs off or never dries
- the printer misses packs intermittently
Likely causes to separate
A symptom can have several unrelated causes. Treat the following as hypotheses to test rather than a list of settings to change at once.
- dirty printhead or incorrect maintenance state
- print distance or angle outside the operating window
- product speed or trigger variation
- wet, cold, oily or incompatible substrate
- ink, make-up or message settings unsuitable
Check in this order
Check 1
Print on the real moving pack at production speed.
Check 2
Inspect printhead condition and diagnostics.
Check 3
Measure throw distance and alignment.
Check 4
Check trigger repeatability and conveyor slip.
Check 5
Test adhesion after the real cooling, condensation and handling process.
Corrective actions to evaluate
After the cause is demonstrated, select the least disruptive correction that returns the process to a safe, repeatable and approved state.
- clean and service the printer to its approved procedure
- restore print distance, angle and encoder/trigger control
- select compatible ink and substrate preparation
- move coding to a dry stable surface where possible
- use code verification for critical readability requirements
Prevent the problem returning
- include print samples in start-up approval
- control message selection and permissions
- maintain printhead cleaning schedules
- retain substrate and ink compatibility records
Record evidence, not only the final setting
Capture the product and packaging batches, machine recipe, head or lane, speed, temperature, vessel level, symptom frequency, intervention and post-correction results. This creates a usable centreline and allows recurring loss to be prioritised through OEE or downtime analysis.
Common questions
What is the first check for poor date-code and batch-code print quality?
Print on the real moving pack at production speed.
What commonly causes poor date-code and batch-code print quality?
Common causes include dirty printhead or incorrect maintenance state, print distance or angle outside the operating window, product speed or trigger variation.
Should the machine be adjusted immediately?
Change one controlled variable at a time after the measurement method, product condition, packaging and safety state are confirmed.
When should production be stopped?
Stop and follow the site safe-isolation and escalation procedure when there is risk of injury, contamination, fire or explosion, uncontrolled product release, damaged guards, unsafe pressure or an unverified quality result.
What information should be recorded?
Record product and pack batch, recipe, machine settings, filling head or lane, time, temperature, speed, symptom, corrective action and the evidence that performance returned to the approved condition.