A common task in the food processing industry is to weigh and label items. The instruments used in such a process are subject to regulatory control. Specifically the weighing means, e.g. any type of weighing device, is subject to examination and certification by official authorities. When the weight data obtained from such an instrument is printed on a label that is to be affixed to the weighed item the printed weight is by the letter of the regulation (if not always in practice) also subject to regulatory control in the sense that the printed weight must be the same weight as is recorded by the scale.
If a label printer is directly connected to the weighing means the label printer is considered to be under full control of the scale and is therefore covered by the certification of the scale.
In many cases however the weight data is passed from the scale to a computer system which formats the label information before sending it to the label printer. In such instances the label printer is not considered to be under full control of the scale and is therefore not covered by the certification of the scale.
There can be many reasons why such an arrangement is used instead of printing the label directly from the scale. The most common one is that it's impractical to convey all the information that needs to be on such a label to the scale. Label designs can be quite complex and have multiple variable items of information on them, e.g. a barcode, expiry date, price per kg, net weight, total price, packing date, lot number, storing information, content information etc.
Another reason could be that the label is to be printed at a later stage, such as shortly before the item is to be palletized. This may be because the time from where the weighing takes place until the item is e.g. palletized can be few seconds or even few minutes (or even longer) but during this time the items may e.g. be damaged or even accidentally drop from a conveyor conveying the items and thus get lost in the system. It is thus preferred not to assign the items to e.g. a given pallet until it is ensured that the items are actually there, i.e. as close to the pallet as possible.
Another reason could be that the item requires a customer-specific label but has not been sold to a customer at the time it is weighed. Thus, it may be preferred to produce items in one location, ship them to a distribution centre and label them when they are shipped to final customers.
In current solutions that exist today, in the above mentioned scenarios it cannot be guaranteed to the satisfaction of the authorities that weighing data has not been manipulated with when the actual labelling takes place.