Carton Trigger For Date/Lot Code Printing

Carton Trigger for Date/Lot  Code Printing Image

Application: Detecting leading edge of carton

Challenges: Carton surface can be glossy and multi-colored and hard to detect

Solution: QS18LLP accurately detects the leading edge with no chatter

Benefits: Accurate timing for printing and inspection assures consistent quality


When packaging frozen dinners, the date/lot code must be printed on the package and then verified for quality assurance. Because of the cartons’ glossy, multi-color surface, finding a sensor that consistently detects the carton’s leading edge—signaling the precise time to print the date/lot code and capture the image for quality assurance—without excess chatter is challenging.


With a narrow beam that projects a small bright spot, the QS18LLP laser, polarized, retro-reflective sensors provide precise position control when triggering various devices. In this application, the QS18LLP is able to correctly detect the glossy carton as it travels down the conveyor—without proxing—and trigger the ink jet printer to print the date/lot code on the carton. The second sensor triggers the P4 OMNI to inspect the date/lot code and verify it is legible and correct.

By using the QS18LLP combined with the P4 OMNI, manufacturers are able to print date/lot codes at exactly the right moment, verify printing quality and confirm code use—ensuring identical, consistent packages and avoiding costly packaging errors—and reject packages with deformities or incorrect date/lot codes.

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