Technology comparison

technologY COMPARISON

The extensive use of bar codes for automatic product identification has brought about major advances for the whole of industry in terms of logistics and traceability.

One of the main requirements is the zero-tolerance of printing errors. A spelling mistake in a word does not necessarily change its meaning; however, a poorly printed bar code renders it unusable.

Different technologies exist for printing variable label information: which one is best suited to different operational demands ?

The term "direct thermal" applies to a printing technique which does not use any inked consumables. The chemically-treated print media turns black when passed under heating elements in the printhead of the thermal printer.

Advantages :

Thermal printers are well-suited to the industrial environment,
A single consumable to deal with: the thermal label,
Robust equipment with low maintenance requirements,
Good, sharp print quality: suitable for bar code printing,
Acceptable print speed for industrial demands.

Disadvantages :

Poor label longevity due to sensitivity to heat, UV, friction and solvents,
Black is practically the only available colour,
Choice of print media limited to paper,
Label in direct contact with printhead, thereby necessitating frequent replacement.

Conclusion :
A good solution for printing variable information to last for just a short period of time (from a few days to a few weeks) such as on till receipts and airport luggage labels. Not suitable for bar code printing which requires a long shelf life.

Inkjet printers are widely used for home printing and sometimes by businesses. Printing is carried out by spraying micro-drops of ink onto the print medium.

Advantages :

Ability to print in colour,
Affordable printers which are readily interchangeable and often already present in companies,
Label sheets are available from standard distribution outlets.

Disadvantages :

The low resistance to heat and solvents reduces the longevity of the print,
Limited range of suitable print media,
Inability to print rolls of labels, just sheets which require more handling and generate waste,
Low print speed,
Very high printing costs,
Long drying time,
Printer mechanisms are not suitable for the industrial environment: humidity, dust, high temperatures, vibration etc.

Conclusion
A suitable technique for printing small quantities of box labels, but of limited use for high volume printing which requires speed, reliability and low cost.

Just as with inkjet, laser printers are very widespread in companies and also in home printing. The technique consists of using the electrostatic properties of powdered ink (toner) to transfer it onto the print medium. The ink is then fused by the application of heat.

Advantages :

High print quality,
Ability to print in colour,
Large numbers of printers used by companies,
Label sheets available in the shops or by office equipment mail order/e-commerce outlets.

Disadvantages :

Limited label choice,
Inability to print rolls of labels, just sheets,
Low print speed, incompatible with some production lines,
Very high cost of consumables (cartridges + drums). Ink consumption for a bar code is higher than for straightforward text,
Unsuitable for use in the industrial environment.

Conclusion :
In companies, laser can be used for occasional label printing but the technique is unsuitable for printing in the industrial environment due to cost and technical constraints.

Printing by "thermal transfer" works by combining a printer with thermal head, an inked ribbon and a print medium. The ribbon’s ink is transferred onto the label when it passes under the printhead.

Advantages :

Printers ideally suited to the industrial environment,
Ability to print on numerous print media: paper, synthetics or textiles,
Very low printer maintenance thanks to robustness of materials used and the TT ribbon "backcoating" which provides the printhead with longer-lasting protection,
Excellent print quality (high resolution, sharpness and blackness of characters), even at very high speed,
Depending on the ribbon selected, TT offers excellent levels of resistance: abrasion, light, temperature, and solvents.

Disadvantages :

2 consumables to handle, the print medium and the ribbon,
Impossible to print more than one colour at the same time,
Printed information is legible on the leftover inked ribbon which can give rise to issues of confidentiality.

Conclusion :
A particularly suitable technology for label printing in the industrial environment. TT meets the demands of very different applications: from the low-cost solution with a short shelf-life to the long-lasting and high resistance solution. Where quality and reliability are indispensable, TT is the solution.

Continuous inkjet uses ink and a set of electrostatically charged plates to spray drops of ink onto the print medium to form letters or numbers.

Advantages :

No direct contact with print medium, thereby enabling printing to be made on uneven surfaces,
The ink can be set onto several types of media: cardboard, paper, glass, plastic, metal, eggshell etc,
A suitable technique for package identification thanks to high print speed,
Coloured ink available,
Collection and reuse of non-printed ink,
Rapid ink drying time (1 second).

Disadvantages :

Low resistance of the print in hostile environments: friction, solvents etc,
Not suitable when the print medium is dusty, hot or wet,
Regular maintenance due to clogged nozzles caused by certain impurities in the salvaged ink,
Modifications to work station required (solvent extraction system, for example).

Conclusion :
Continuous inkjet is a particularly well-suited technology for printing small characters on numerous media, but has weaknesses for printing traceability information such as bar codes.

Identification by radio-frequency enables the information contained in a label to be read remotely via the presence of an electronic chip. The information is received by a sensor which reads and transmits data.

Advantages :

Information read remotely,
Ability to read several chips at the same time,
RFID tags can also be used as anti-theft and anti-counterfeiting devices,
Available in many sizes and shapes, RFID tags are compatible with numerous different applications.

Disadvantages :

High installation costs: chips and RFID readers,
Level of errors still high,
As of yet, no worldwide standard regarding frequencies to be used,
The information contained on the chip is also printed on the label to compensate for the unreliable technology and the lack of chip readers.

Conclusion :
RFID currently complements other automatic identification technologies. Its development depends on the cost savings it is able to make and the improvement in its reliability.

The heat produced by a laser beam generates a mark on the targeted medium. This technique is widely used for marking plastic bottles and metal items.

Advantages :

No inked consumables are used, thereby dispensing with some maintenance operations,
Lasers do not require a flat print medium,
Ideally suited to variable information and therefore to IT data management,
Etching gives marking which is durable and resistant to abrasion and solvents,
Laser operation speeds are compatible with production lines.

Disadvantages :

The technology requires extremely precise pre-setting before carrying out a print run,
The laser can melt over-delicate print media (paper labels, plastic film, food packaging etc.),
Laser technology must be used in a safe environment due to the risk to users,
Risk of emission of toxic fumes depending on the type of print medium used,
Lack of colour poses readability problems on some coloured media,
High equipment cost.

Conclusion :
Printing using laser etching is particularly well-suited to printing on certain thick media but remains of limited use due to relative lack of compatible media.

Printing by hot stamping requires the use of an inked ribbon which is struck by a heated stamp, causing the ink to be transferred onto the product.

Advantages :

Good resistance of the printed message thanks to the quality of the ink and the impression,
Straightforward printing technique due to the relative lack of technology employed,
Ability to use different types of consumables: coloured ribbons, holograms, decoration, metallisation etc,
Simpler technology requiring little maintenance.

Disadvantages :

The stamp is an engraved item and cannot therefore print variable information,
The use of a heated press (stamp) can alter the print medium, thereby significantly limiting its use for printing on paper.

Conclusion :
Printing by hot stamping is a simple technology to use and presents few difficulties. However, it does not offer sufficient print flexibility to be more widely used in the field of automatic identification.