Rollstock Eye Marks: Approve the Sensor Track Before Printing

A snack-film or personal-care sachet project can have an attractive repeat layout and an incomplete registration specification. Ask the co-packer for the intended machine, sensor requirement, mark side, web direction, repeat and position relative to the cut or sealing reference. Keep this information on a drawing rather than resolving orientation through informal descriptions.

The rollstock specification guide covers the complete supply brief. This review focuses on what the sensor encounters as the web moves. It is not a procedure for installing, tuning or bypassing machine controls.

SICK’s registration-mark design guidance shows how other artwork in the sensor’s path can create false triggers. Its examples also show why the mark’s color and position need to be evaluated together. Those examples concern particular contrast and color-sensing approaches; they are not a universal black-mark rule or a standard mark dimension.

On the artwork drawing, trace the route that passes the sensing point through one full repeat. Include text, background changes, decorative blocks and any area where the surface changes. Ask the machine owner to confirm that the proposed path and the final film finish are appropriate for the actual sensor. A visual review is the start of that handoff, not proof of reliable machine detection.

The following original worksheet assigns the missing decisions to the people who can confirm them. Attach the same revision of the drawing to each response.

A loose film strip can be shown from either side or rotated on a desk. Label the sample’s printed side, web direction and mark edge so that the review maps to the roll the co-packer will receive. Have the machine owner reconcile the sample with the unwind drawing before approving the order.

Use a sample that represents the relevant printed background and surface. If only a digital proof is available, record the machine trial as pending. A proof can settle artwork location while leaving the optical response of the finished film unverified. Keep those two decisions visible rather than treating artwork approval as blanket line approval.

If a trial misses the intended mark or triggers on another feature, identify where in the repeat that happened. Record the sample revision and the operating context with the equipment owner. A supplier should not be asked to move the mark until the parties know which layout or equipment requirement the change must satisfy.

A change to the read path, print background, finish or sensor setup can change the question being tested. Review the affected evidence when one of those changes. Keep rollstock splice requirements separate: an approved eye mark does not establish splice detection or handling.

For custom printed rollstock, provide the product, intended construction, web width, repeat, roll format and quantities by artwork. Attach the machine requirement, unwind drawing and annotated sensor track. Identify who can approve a trial at the filling site.

Ask P&M to review the packaging specification and identify the available sample route, cost and timing. Confirm any unresolved machine requirement with the co-packer before production. This process does not prescribe one mark size, contrast value or guaranteed reject reduction for every line.