Error marking, test marking & inspection marking

Labelling devices for error marking and test marking

Even in modern production, rejects cannot always be avoided. The higher the quality and durability of a part or product, the higher the demands on quality and accuracy. Defect marking and inspection marking are therefore an integral part of such production processes and serve to mark the rejects or parts for reworking. Defect marking and inspection marking are usually very simple marking processes, mostly consisting of only a small coloured marking (coloured dot). With the help of special inks, however, it is also possible to create largely invisible defect (error) markings and test markings. Special black light inks then only become visible under UV light.

The surface to be marked is of decisive importance for the suitable type of error marking and test marking. The material, the size and whether the surface is flat or curved all play a role here. Inkjet solutions are therefore particularly well suited here. Their non-contact printing and fast processing speed make them easy to integrate into existing production processes. The large selection of special inks makes the type of defect marking and inspection marking very flexible.

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In today’s competitive manufacturing landscape, product quality is directly tied to brand reputation, regulatory compliance, and operational efficiency. One of the most effective yet often underestimated tools in quality control is defect marking and inspection marking using TIJ (Thermal Inkjet) marking systems.

From automotive components to food packaging and electronics, TIJ marking systems provide precise, high-resolution printing that enables manufacturers to identify, track, and control non-conforming products in real time. This article explores why defect marking and inspection marking are essential and how TIJ technology enhances quality assurance processes.

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What Is Defect Marking?

Defect marking is the process of clearly identifying products that fail quality checks during manufacturing. These marks can include:

• “Rejected” labels
• X marks or colored indicators
• Special symbols or codes
• Machine-readable barcodes
• Internal tracking numbers

The purpose of defect marking is simple: prevent faulty products from progressing further in the production line or reaching customers.

Without reliable marking, defective products may be accidentally mixed with approved items—leading to costly recalls, warranty claims, and reputational damage.

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What Is Inspection Marking?

Inspection marking confirms that a product has passed a specific quality control checkpoint. These markings may indicate:

• Visual inspection completed
• Electrical testing passed
• Weight verification approved
• Packaging integrity confirmed
• Compliance validation achieved

Inspection marks create a documented trail of quality verification throughout the production process.

When integrated with digital systems, inspection marking becomes a powerful traceability tool within a broader quality management system (QMS).

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NasaJet® NJ-1000 und NJ-2000 for test, error and inspection marking

The NasaJet® NJ-1000 and NJ-2000 models are suitable for retrofitting into existing production lines. These two proven marking systems consist of a control unit with built-in touch screen and a print head connected by cable. The print head can then be mounted accordingly on existing assembly lines. External sensors can be used to trigger the printing process. This allows any other system to check for faults and trigger the print. The printing speed can be up to a maximum of 50m per minute. The units are therefore particularly suitable for marking objects in rapid succession.

With the proven TIJ principle, almost any surface (smooth, curved, rough,...) can be printed. Inks and special inks for a wide range of materials are available from various suppliers. Even special applications (invisible UV ink, waterproof,...) can be realised.

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Hand printer for error marking and test marking

In addition to their mobility and flexibility, the big plus points of hand printers are their cost-effectiveness. Modern hand printers today have moderate purchase costs, low energy consumption and allow variable use of the amount of ink required. Hand printers can be used for error marking and inspection marking of very large or bulky objects - such as building materials or prefabricated house parts.