A poorly specified eye mark can make correct artwork cut or seal in the wrong place. I define the machine reference before approving the print file.

I specify an eye mark from the machine sensor, web direction, repeat length, mark track, contrast, size, and cutoff offset. Buyers should get the machine maker's written requirements, place the mark on the approved dieline, and test printed film at production speed before bulk release.

An eye mark is small, but it connects artwork to machine movement. The following checks turn that small graphic into a controlled production parameter.

What Information Must Come From the Packing Machine?

An eye mark copied from another film may look familiar but remain unreadable on a different line. The sensor and control logic must lead the specification.

Buyers should request the accepted mark size, color or contrast range, sensor type, sensing side, track position, web direction, repeat length, cutoff offset, and required clear area from the machine maker, operator, or co-packer. I use those values rather than a generic template.

I begin with a machine data sheet

The packing machine uses a sensor to detect a predictable change in the moving web. That detection gives the control system a reference for the package cycle. The machine may then use an offset from the detected mark to coordinate film advance, sealing, or cutting. The mark therefore does not always sit exactly on the finished cut line.

I ask the buyer to get the requirement from the person who owns the line setup. That person may be the machine manufacturer, maintenance team, production engineer, or contract packer. A screenshot of an old bag is not enough because it does not define the sensor path, mark dimensions, background, or direction of travel.

I also confirm whether the roll will run on one machine or several. If several lines must share the film, the buyer should identify a mark specification that every intended sensor can read. That compatibility must be demonstrated on the lines, not assumed from drawings.

How Should Buyers Choose Eye-Mark Contrast and a Clear Track?

A dark mark is not automatically a readable mark. The sensor sees contrast against its immediate background, while nearby artwork can create competing signals.

I choose the mark and background as a tested pair. The mark needs stable contrast for the specified sensor, and its travel track should remain free from logos, text, color blocks, varnish changes, metallic effects, windows, or other features that could trigger or weaken detection.

I evaluate the complete printed surface

Buyers sometimes request a black rectangle because black is commonly visible. That choice can work, but the actual question is whether the sensor distinguishes the mark from the material and every other printed feature in the sensing path. A dark mark over a dark design may offer little useful difference. A clear or reflective area can also behave differently from an opaque printed background.

I ask the buyer to provide the machine maker's guidance on accepted colors, reflectance or contrast, mark dimensions, and required quiet zone. I do not invent universal values because sensor technologies, mounting, web surfaces, and line conditions differ. The production team may need to teach or tune the sensor for the approved film.

I protect the sensor track in the artwork

The artwork file should show a dedicated path running in the direction of film travel. I keep uncontrolled graphics out of that path. I also check whether a matte or gloss finish, metallic layer, transparent window, white ink, or design change passes beneath the sensor. These features can change the optical background even when the eye mark itself remains unchanged.

XINYUAN provides free artwork and typesetting service, so I can place the confirmed mark and protected track on the production layout. If the design requires printing plates, a plate fee may apply. The fee is paid to the plate-making factory. When the same printing pattern is reused later, a new plate fee is normally unnecessary, subject to the confirmed quotation. This is another reason to settle the machine specification before plates are made.

Where Should the Eye Mark Sit Relative to Repeat Length and Unwind Direction?

Correct color in the wrong location still fails. The eye mark must arrive at the sensor on the correct web edge, face, and point in each printed repeat.

I position the eye mark only after confirming the finished package orientation, web width, repeat length, sealant side, unwind direction, sensing side, and cutoff offset. The approved drawing should dimension the mark from stable web and repeat references rather than from a movable artwork element.

I connect three drawings

I compare the finished package view, the flat print layout, and the roll-unwind diagram. The finished front panel may appear upright to a buyer, while the artwork enters the machine from a different direction. Without these three views, “left side” or “top edge” can become ambiguous.

The repeat length defines how often the printed package design and eye mark recur along the web. The sensor detects the mark, and the machine applies its programmed relationship to the sealing and cutoff cycle. I therefore ask the operator to confirm whether the mark leads or trails the relevant package reference and how the offset is entered on the machine.

I document the mark with fixed references

The approved file should show the web width, repeat length, print direction, unwind direction, sealant orientation, mark size, distance from the selected web edge, position within the repeat, clear track, and intended cutoff relationship. A roll sketch should show which face is visible from outside and which edge reaches the sensor.

XINYUAN visibly offers film rolls within our packaging range. Buyers can review our broader product scope on the XINYUAN packaging homepage. I still request the exact line data for every film-roll project because an eye-mark layout cannot be transferred safely from one machine setup to another without confirmation.

What Should Buyers Test Before Releasing Bulk Film?

A static proof can confirm placement but cannot prove reliable detection. Only a representative printed roll running on the intended equipment tests the complete system.

Buyers should test web loading, sensor teaching, mark detection, registration stability, seal and cut position, acceleration, normal speed, stops, restarts, and roll changes. They should approve the printed result, record machine settings, and define an incoming inspection method before bulk production.

I recommend a controlled line trial

The test film should represent the intended material structure, surface finish, background, printing, web width, repeat, and unwind direction as closely as the project requires. A blank film test cannot prove that the final optical contrast will work. Likewise, a hand-held sensor check does not reproduce web speed, tension, vibration, or changing ambient conditions on the line.

The operator should load the roll using the approved unwind diagram, align the sensor with the mark track, and follow the machine maker's setup procedure. The trial should start slowly, then cover the intended operating range. I ask the buyer to inspect consecutive packs for print-to-cut and print-to-seal position, while also watching for missed marks or false triggers.

I freeze the approved data for reorders

After acceptance, I recommend keeping the signed artwork, print layout, roll diagram, machine identification, approved sample, settings record, and inspection criteria together. Any change in machine, sensor, artwork background, film finish, web width, repeat, unwind direction, or mark can justify another review and trial.

Our integrated production system covers raw-material production through finished products, and our organization supports large orders and long-term supply. I present stable execution as our operating focus, not an unconditional guarantee. A buyer's strongest reorder control is still a complete, versioned specification that connects the printed roll to the actual packing line.

Conclusion

I specify eye marks from verified machine data, protect their contrast and track, dimension their roll position, and confirm performance through a representative production-speed trial.